Advances in microbial leaching processes for nickel extraction from lateritic minerals - A review

International Nuclear Information System (INIS)

Behra, Sunil Kumar; Mulaba-Bafubiandi, Antoine Floribert

2015-01-01

Lateritic nickel minerals constitute about 80% of nickel reserves in the world, but their contribution for nickel production is about 40%. The obstacles in extraction of nickel from lateritic minerals are attributed to their very complex mineralogy and low nickel content. Hence, the existing metallurgical techniques are not techno-economically feasible and environmentally sustainable for processing of such complex deposits. At this juncture, microbial mineral processing could be a benevolent approach for processing of lateritic minerals in favor of nickel extraction. The microbial mineral processing route offers many advantages over conventional metallurgical methods as the process is operated under ambient conditions and requires low energy input; thus these processes are relatively simple and environment friendly. Microbial processing of the lateritic deposits still needs improvement to make it industrially viable. Microorganisms play the pivotal role in mineral bio-processing as they catalyze the extraction of metals from minerals. So it is inevitable to explore the physiological and bio-molecular mechanisms involved in this microbe-mineral interaction. The present article offers comprehensive information about the advances in microbial processes for extraction of nickel from laterites.

Advances in microbial leaching processes for nickel extraction from lateritic minerals - A review

Energy Technology Data Exchange (ETDEWEB)

Behra, Sunil Kumar; Mulaba-Bafubiandi, Antoine Floribert [Faculty of Engineering and the Built Environment, University of Johannesburg, (South Africa)

2015-08-15

Lateritic nickel minerals constitute about 80% of nickel reserves in the world, but their contribution for nickel production is about 40%. The obstacles in extraction of nickel from lateritic minerals are attributed to their very complex mineralogy and low nickel content. Hence, the existing metallurgical techniques are not techno-economically feasible and environmentally sustainable for processing of such complex deposits. At this juncture, microbial mineral processing could be a benevolent approach for processing of lateritic minerals in favor of nickel extraction. The microbial mineral processing route offers many advantages over conventional metallurgical methods as the process is operated under ambient conditions and requires low energy input; thus these processes are relatively simple and environment friendly. Microbial processing of the lateritic deposits still needs improvement to make it industrially viable. Microorganisms play the pivotal role in mineral bio-processing as they catalyze the extraction of metals from minerals. So it is inevitable to explore the physiological and bio-molecular mechanisms involved in this microbe-mineral interaction. The present article offers comprehensive information about the advances in microbial processes for extraction of nickel from laterites.

Nature and Properties of Lateritic Soils Derived from Different Parent Materials in Taiwan

Directory of Open Access Journals (Sweden)

Tzu-Hsing Ko

2014-01-01

Full Text Available The objective of this study was to investigate the physical, chemical, and mineralogical composition of lateritic soils in order to use these soils as potential commercial products for industrial application in the future. Five lateritic soils derived from various parent materials in Taiwan, including andesite, diluvium, shale stone, basalt, and Pleistocene deposit, were collected from the Bt1 level of soil samples. Based on the analyses, the Tungwei soil is an alfisol, whereas other lateritic soils are ultisol. Higher pH value of Tungwei is attributed to the large amounts of Ca2+ and Mg2+. Loupi and Pingchen soils would be the older lateritic soils because of the lower active iron ratio. For the iron minerals, the magnetic iron oxides such as major amounts of magnetite and maghemite were found for Tamshui and Tungwei lateritic soils, respectively. Lepidocrocite was only found in Soka soil and intermediate amounts of goethite were detected for Loupi and Pingchen soils. After Mg-saturated and K-saturated processes, major amounts of mixed layer were observed in Loupi and Soka soils, whereas the montmorillonite was only detected in Tungwei soil. The investigation results revealed that the parent materials would play an important role during soil weathering process and physical, chemical, and mineralogy compositions strongly affect the formation of lateritic soils.

Nature and Properties of Lateritic Soils Derived from Different Parent Materials in Taiwan

Science.gov (United States)

2014-01-01

The objective of this study was to investigate the physical, chemical, and mineralogical composition of lateritic soils in order to use these soils as potential commercial products for industrial application in the future. Five lateritic soils derived from various parent materials in Taiwan, including andesite, diluvium, shale stone, basalt, and Pleistocene deposit, were collected from the Bt1 level of soil samples. Based on the analyses, the Tungwei soil is an alfisol, whereas other lateritic soils are ultisol. Higher pH value of Tungwei is attributed to the large amounts of Ca2+ and Mg2+. Loupi and Pingchen soils would be the older lateritic soils because of the lower active iron ratio. For the iron minerals, the magnetic iron oxides such as major amounts of magnetite and maghemite were found for Tamshui and Tungwei lateritic soils, respectively. Lepidocrocite was only found in Soka soil and intermediate amounts of goethite were detected for Loupi and Pingchen soils. After Mg-saturated and K-saturated processes, major amounts of mixed layer were observed in Loupi and Soka soils, whereas the montmorillonite was only detected in Tungwei soil. The investigation results revealed that the parent materials would play an important role during soil weathering process and physical, chemical, and mineralogy compositions strongly affect the formation of lateritic soils. PMID:24883366

Effect on physical properties of laterite soil with difference percentage of sodium bentonite

Science.gov (United States)

Kasim, Nur Aisyah; Azmi, Nor Azizah Che; Mukri, Mazidah; Noor, Siti Nur Aishah Mohd

2017-08-01

This research was carried out in an attempt to know the physical properties of laterite soil with the appearance of difference percentage of sodium bentonite. Lateritic soils usually develop in tropical and other regions with similar hot and humid climate, where heavy rainfall, warm temperature and well drainage lead to the formation of thick horizons of reddish lateritic soil profiles rich in iron and aluminium. When sodium predominates, a large amount of water can be absorbed in the interlayer, resulting in the remarkable swelling properties observed with hydrating sodium bentonite. There are some basic physical properties test conducted in this research which are Specific Gravity Test, pH Test, Sieve Analysis, Hydrometer Test, Shrinkage Limit and Atterberg Limit. The test will be conducted with 0%, 5%, 10%, 15% and 20% of sodium bentonite. Each test will be repeated three times for the accuracy of the result. From the physical properties test the soil properties characteristic react with the sodium bentonite can be determine. Therefore the best percentage of sodium bentonite admixture can be determined for laterite soil. The outcomes of this study give positive results due to the potential of sodium bentonite to improve the laterite soil particle.

Analysis of ASTER data for mapping bauxite rich pockets within high altitude lateritic bauxite, Jharkhand, India

Science.gov (United States)

Guha, Arindam; Singh, Vivek Kr.; Parveen, Reshma; Kumar, K. Vinod; Jeyaseelan, A. T.; Dhanamjaya Rao, E. N.

2013-04-01

Bauxite deposits of Jharkhand in India are resulted from the lateritization process and therefore are often associated with the laterites. In the present study, ASTER (Advanced Space borne Thermal Emission and Reflection Radiometer) image is processed to delineate bauxite rich pockets within the laterites. In this regard, spectral signatures of lateritic bauxite samples are analyzed in the laboratory with reference to the spectral features of gibbsite (main mineral constituent of bauxite) and goethite (main mineral constituent of laterite) in VNIR-SWIR (visible-near infrared and short wave infrared) electromagnetic domain. The analysis of spectral signatures of lateritic bauxite samples helps in understanding the differences in the spectral features of bauxites and laterites. Based on these differences; ASTER data based relative band depth and simple ratio images are derived for spatial mapping of the bauxites developed within the lateritic province. In order to integrate the complementary information of different index image, an index based principal component (IPC) image is derived to incorporate the correlative information of these indices to delineate bauxite rich pockets. The occurrences of bauxite rich pockets derived from density sliced IPC image are further delimited by the topographic controls as it has been observed that the major bauxite occurrences of the area are controlled by slope and altitude. In addition to above, IPC image is draped over the digital elevation model (DEM) to illustrate how bauxite rich pockets are distributed with reference to the topographic variability of the terrain. Bauxite rich pockets delineated in the IPC image are also validated based on the known mine occurrences and existing geological map of the bauxite. It is also conceptually validated based on the spectral similarity of the bauxite pixels delineated in the IPC image with the ASTER convolved laboratory spectra of bauxite samples.

SAND-LATERITE MIXTURES FOR ROAD CONSTRUCTION (A ...

African Journals Online (AJOL)

Dr Obe

costs in the construction of roads carrying medium density traffic and in the ... East Asia (1) but for reasons given later, their results ... that laterites are good materials for road and air-field ... countries like South Africa, this method of soil-.

Mechanistic and Kinetic Analysis of Na2SO4-Modified Laterite Decomposition by Thermogravimetry Coupled with Mass Spectrometry.

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Song Yang

Full Text Available Nickel laterites cannot be effectively used in physical methods because of their poor crystallinity and fine grain size. Na2SO4 is the most efficient additive for grade enrichment and Ni recovery. However, how Na2SO4 affects the selective reduction of laterite ores has not been clearly investigated. This study investigated the decomposition of laterite with and without the addition of Na2SO4 in an argon atmosphere using thermogravimetry coupled with mass spectrometry (TG-MS. Approximately 25 mg of samples with 20 wt% Na2SO4 was pyrolyzed under a 100 ml/min Ar flow at a heating rate of 10°C/min from room temperature to 1300°C. The kinetic study was based on derivative thermogravimetric (DTG curves. The evolution of the pyrolysis gas composition was detected by mass spectrometry, and the decomposition products were analyzed by X-ray diffraction (XRD. The decomposition behavior of laterite with the addition of Na2SO4 was similar to that of pure laterite below 800°C during the first three stages. However, in the fourth stage, the dolomite decomposed at 897°C, which is approximately 200°C lower than the decomposition of pure laterite. In the last stage, the laterite decomposed and emitted SO2 in the presence of Na2SO4 with an activation energy of 91.37 kJ/mol. The decomposition of laterite with and without the addition of Na2SO4 can be described by one first-order reaction. Moreover, the use of Na2SO4 as the modification agent can reduce the activation energy of laterite decomposition; thus, the reaction rate can be accelerated, and the reaction temperature can be markedly reduced.

chemical and mineralogical characterization of lateritic iron ore

African Journals Online (AJOL)

DJFLEX

2010-04-22

Apr 22, 2010 ... The laterite iron ore deposit at Auchi, Edo State, Nigeria was studied chemically and mineralogically. The results of the chemical ... SAMPLE PREPARATION. The samples .... 2µm) and were subjected to X-ray diffraction using.

geometric models for lateritic soil stabilized with cement

African Journals Online (AJOL)

user

stabilized lateritic soil and also to develop geometric models. The compaction, California .... on how effective limited field data are put to use in decision-making. ..... silicates was described as the most important phase of cement and the ...

The contribution of lateritization processes to the formation of the kaolin deposits from eastern Amazon

Science.gov (United States)

da Costa, Marcondes Lima; Sousa, Daniel José Lima; Angélica, Rômulo Simões

The eastern region of the Amazon is home to the most important kaolin bauxite producing district in Brazil, referred to as the Paragominas-Capim kaolin bauxite district, which has a reserve of at least 1.0 billion tons of high-quality kaolin used in the paper coating industry. The kaolin deposits are closely related to sedimentary rocks of the Parnaíba basin and their lateritic cover. Two large deposits are already being mined: IRCC (Ipixuna) and PPSA (Paragominas). The geology of the IRCC mine is comprised of the kaolin-bearing lower unit (truncated mature laterite succession derived from the Ipixuna/Itapecuru formation) and the upper unit (immature lateritized Barreiras formation). The lower kaolin unit is characterized by a sandy facies at the bottom and a soft (ore) with flint facies at the top. It is formed by kaolinite, quartz, some iron oxi-hydroxides, mica and several accessories and heavy minerals. The mangrove covering; and immature lateritization - partial kaolin ferruginization during the Pleistocene.

Potential for cobalt recovery from lateritic ores in Europe

Science.gov (United States)

Herrington, R.

2012-04-01

Cobalt is one of the 'critical metals' identified under the EU Raw Materials Initiative. Annually the global mine production of cobalt is around 55,000 tonnes,with Europe's industries consuming around 30% of that figure. Currently Europe produces around 27 tonnes of cobalt from mines in Finland although new capacity is planned. Co-bearing nickel laterite ores being mined in Greece, Macedonia and Kosovo where the cobalt is currently not being recovered (ores have typical analyses of 0.055% Co and >1% Ni,). These ores are currently treated directly in pyrometallurgical plants to recover the contained nickel and this process means there is no separate cobalt product produced. Hydrometallurgical treatment of mineralogically suitable laterite ores can recover the cobalt; for example Cuba recovers 3,500 tonnes of cobalt from its laterite mining operations, which are of a similar scale to the current European operations. Implementation of hydrometallurgical techniques is in its infancy in Europe with one deposit in Turkey planning to use atmospheric heap leaching to recover nickel and copper from oxide-dominated ores. More widespread implementation of these methods to mineralogically suitable ore types could unlock the highly significant undeveloped resources (with metal contents >0.04% Co and >1% Ni), which have been defined throughout the Balkans eastwards into Turkey. At a conservative estimate, this region has the potential to supply up to 30% of the EU cobalt requirements.

Mineralogical and geochemical trends in lateritic weathering profiles ...

African Journals Online (AJOL)

The absence of bauxite minerals like gibbsite and diaspora in the profiles shows that the trend of weathering is towards iron enrichment (ferralitization) and not aluminum accumulation (bauxitization). The CIA values of the lateritic layers shows that the weathering process is matured and has reached advanced stage.

Dating Amazonian laterites through the novel geochronometers kaolinite and iron oxides

Science.gov (United States)

Allard, Thierry; Bressan Riffel, Silvana; Gautheron, Cécile; Fernandes Soares, Bruna; Pinna-Jamme, Rosella; Morin, Guillaume

2016-04-01

Soils on Earth's surface are in constant interaction with climate. As a matter of fact, soils cannot only produce greenhouse effect gases, such as NO2 and CH4, but also behave as sinks for CO2, especially by silicate weathering. Major processes of silicate weathering are known and exhibit climatic zonation at the global scale. Laterites are particularly relevant because they are ancient and deeply weathered soils of major significance. They occupy 30 % of the continental surface and can keep records of past climates and landscape modifications (paleosurface) through specific mineral markers. These formations reach several tens of meters and are mainly composed of kaolinite, iron and aluminium oxides as well as relicts of parent minerals such as quartz and ancillary minerals. Once the major processes of laterite formation are known, their age will allow a growth of researches, owing to the implementation of various chronometers. Moreover, it is fundamental to date laterites in order to improve our understanding of soil formation related to paleoclimates, and to build predictive models of their evolution. In this study, we focus on comparing kaolinite ages with the still unknown ages of lateritic duricrusts from the central Amazon region (Brazil), where strong weathering processes were developed from the early Tertiary, after the Andean uplift. The central Amazon region displays flat areas and dissected plateaus (100-180 m a.s.l.) sustained by weathered clastic sedimentary rocks and latosols. The region contains horizons of duricrusts, relatively continuous layers of Fe-cuirasses, stratified lateritic profiles, and kaolin deposits. Here we employed two methods to date ubiquitous secondary minerals of laterite, which are consistent with geological time-scale. The corresponding geochronometers are the following: (i) radiation-induced defects in kaolinite (trapped in duricrusts) analysed by electron paramagnetic resonance spectroscopy (EPR) (Balan et al., 2005), and (ii

stabilization of ikpayongo laterite with cement and calcium carbide

African Journals Online (AJOL)

PROF EKWUEME

Laterite obtained from Ikpayongo was stabilized with 2-10 % cement and 2-10 % Calcium Carbide waste, for use .... or open dumping which have effect on surface and ... Table 1: Chemical Composition of Calcium Carbide Waste and Cement.

ESR dating of laterite from Ban Tha Ta Suea, Kanchanaburi, Thailand

International Nuclear Information System (INIS)

Limsuwan, S.; Vichaidid, T.; Limsuwan, P.

2011-01-01

Electron spin resonance (ESR) dating was carried out on laterite samples collected from Ban Tha Ta Suea, the original deposit of the laterite used in the construction of Muang Sing Historical Park. Ban Tha Ta Suea is about 6 km east of Muang Sing Historical Park in Kanchanaburi province (181 km far from Bangkok). The dose response of the g=2.0028 ESR signal was found to be suitable for age determination. An exponential saturation function was fitted to the ESR signal growth on additional γ-irradiation. Extrapolation of this function resulted in the accumulated dose 144±5 Gy. Gamma spectroscopy and neutron activation analysis (NAA) were used to determine concentrations of 238 U, 232 Th and 40 K in the samples from which the annual dose rate 16±2 mGy was calculated. In addition, the dose rate of cosmic rays was taken into account. The ESR age of laterite samples was found to be 9.0±0.9 ka. This age falls within the Holocene epoch of the Quaternary on the geological time scale. Samples from Muang Sing Historical Park were assigned to the same epoch. Both results agree with the geological map.

Effects of Periwinkle Shell Ash on Lime-Stabilized Lateritic Soil ...

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ADOWIE PERE

Keywords: atterberg limits, lateritic soil, lime stabilization, periwinkle shell ash .... specimen were prepared by carefully and completely ..... Fourth Edition. Canada: CENGAGE Learning. Holtz, RD; Kovacs, WD (1981). ... Potentials of Sugar cane.

Improvement of strength characteristics of lateritic sub-grade soil ...

African Journals Online (AJOL)

Journal of Applied Sciences and Environmental Management ... Abstract. This paper presents the results of investigation of the behavior of pavement subgrade soil stabilized with shredded polyethylene waste. ... Keywords: Lateritic soil, High density polyethylene (HDPE) waste, Pavement thickness, Sub-grade soil ...

Modeling of heat and mass transfer in lateritic building envelopes

International Nuclear Information System (INIS)

Meukam, Pierre

2004-10-01

The aim of the present work is to investigate the behavior of building envelopes made of local lateritic soil bricks subjected to different climatic conditions. The analysis is developed for the prediction of the temperature, relative humidity and water content behavior within the walls. The building envelopes studied in this work consist of lateritic soil bricks with incorporation of natural pozzolan or sawdust in order to obtain small thermal conductivity and low-density materials, and limit the heat transfer between the atmospheric climate and the inside environment. In order to describe coupled heat and moisture transfer in wet porous materials, the coupled equations were solved by the introduction of diffusion coefficients. A numerical model HMtrans, developed for prediction of beat and moisture transfer in multi-layered building components, was used to simulate the temperature, water content and relative humidity profiles within the building envelopes. The results allow the prediction of the duration of the exposed building walls to the local weather conditions. They show that for any of three climatic conditions considered, relative humidity and water content do not exceed 87% and 5% respectively. There is therefore minimum possibility of water condensation in the materials studied. The durability of building envelopes made of lateritic soil bricks with incorporation of natural pozzolan or sawdust is not strongly affected by the climatic conditions in tropical and equatorial regions. (author)

Growing Eremanthus erythropappus in crushed laterite: A promising alternative to topsoil for bauxite-mine revegetation.

Science.gov (United States)

Machado, Naiara Amaral de Miranda; Leite, Mariangela Garcia Praça; Figueiredo, Maurílio Assis; Kozovits, Alessandra Rodrigues

2013-11-15

Topsoil is the preferred substrate for areas requiring rehabilitation after bauxite mining. However, topsoil is sometimes lacking and so there is a need to test the suitability of other, locally available substrates. In an abandoned bauxite mine in Southeastern Brazil, small patches of native vegetation spontaneously established in shallow depressions over weathered laterite, suggesting that granulometric reduction may have facilitated the establishment of plants. To test this hypothesis, blocks of laterite collected in the area were crushed to simulate texture observed in the vegetation patches. Topsoil collected in a preserved ferruginous field near to the extraction area was also used as a substrate in which Eremanthus erythropappus seedlings, a native woody species, were grown. Seedlings were cultivated without fertilizers in these two substrates and also directly over the exposed and uncrushed laterite. The species proved to be very promising for the revegetation, showing a high survival rate in all substrates. Higher annual growth rates and higher final biomass values were observed in topsoil, but the granulometric reduction of laterite doubled plant growth rate in comparison to the exposed laterite. This result was likely due to the increased availability of essential nutrients to plants and to the improvement in physical conditions for root growth and functioning. Moreover, seedling allometry was not altered by the type of substrate, suggesting that the species was highly tolerant to the new substrate conditions, a fundamental characteristic for success of revegetation of bauxite extraction degraded areas. Copyright © 2013 Elsevier Ltd. All rights reserved.

Arsenic adsorption of lateritic soil, limestone powder, lime and fly ash on arsenic-contaminated soil

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Wuthiphun, L.

2007-05-01

Full Text Available Arsenic adsorption efficiency of soil covering materials (lateritic soil, limestone powder, lime and fly ash on arsenic-contaminated soil obtained from Ronpiboon District, Nakhon Sri Thammarat Province tosolve arsenic air pollution problem was investigated using batch experiments. The four types of the aforementioned soil covering materials were examined to determine their arsenic adsorption efficiency, equilibriumtime as well as adsorption isotherms.The results revealed that among soil covering materials mixed with arsenic-contaminated soil at 10% w/w, the efficiency of arsenic adsorption of fly ash, lateritic soil, lime and limestone powder were 84, 60,38 and 1% respectively. The equilibrium time for lateritic soil at pH 4 was achieved within 4 hrs, whereas pH 7 and 12, the equilibrium time was 6 hrs. For fly ash, 2 hrs were required to reach the equilibrium at pH 12, while the equilibrium time was attained within 6 hrs at pH 4 and 7. Furthermore, lateritic soil possessedhigh arsenic adsorption efficiency at pH 7 and 4 and best fit with the Langmuir isotherm. The fly ash showing high arsenic adsorption efficiency at pH 12 and 7 fit the Freundlich isotherm at pH 12 and Langmuirisotherm at pH 7.This indicated that lateritic soil was suitable for arsenic adsorption at low pH, whilst at high pH,arsenic was well adsorbed by fly ash. The Freundlich and Langmuir isotherm could be used to determine quantities of soil covering materials for arsenic adsorption to prevent arsenic air pollution from arseniccontaminated soils.

Compositional and structural characterisation of Ni-phyllosilicates in hydrous silicate type Ni-laterite deposits

OpenAIRE

Villanova de Benavent, Cristina

2015-01-01

Ni-bearing Mg-phyllosilicates (commonly known as garnierites) are significant ore minerals in many Ni-laterite deposits worldwide. However, the characterisation of these mineral phases is complex, as well as their classification and nomenclature, due to their fine-grained nature, low crystallinity and frequent occurrence as mixtures. The aim of this study is to shed some light to the nature of the Ni-bearing Mg-phyllosilicates occurring at the Falcondo Ni-laterite. In this deposit, these ...

Thermodynamic Analysis of the Selective Reduction of a Nickeliferous Limonitic Laterite Ore by Hydrogen

Science.gov (United States)

Elliott, R.; Pickles, C. A.

2017-09-01

Nickeliferous limonitic laterite ores are becoming increasingly attractive as a source of metallic nickel as the costs associated with recovering nickel from the sulphide ores increase. Unlike the sulphide ores, however, the laterite ores are not amenable to concentration by conventional mineral processing techniques such as froth flotation. One potential concentrating method would be the pyrometallurgical solid state reduction of the nickeliferous limonitic ores at relatively low temperatures, followed by beneficiation via magnetic separation. A number of reductants can be utilized in the reduction step, and in this research, a thermodynamic model has been developed to investigate the reduction of a nickeliferous limonitic laterite by hydrogen. The nickel recovery to the ferronickel phase was predicted to be greater than 95 % at temperatures of 673-873 K. Reductant additions above the stoichiometric requirement resulted in high recoveries over a wider temperature range, but the nickel grade of the ferronickel decreased.

Effect of Lime Stabilization on Vertical Deformation of Laterite Halmahera Soil

Science.gov (United States)

Saing, Zubair; Djainal, Herry

2018-04-01

In this paper, the study was conducted to determine the lime effect on vertical deformation of road base physical model of laterite Halmahera soil. The samples of laterite soil were obtained from Halmahera Island, North Maluku Province, Indonesia. Soil characteristics were obtained from laboratory testing, according to American Standard for Testing and Materials (ASTM), consists of physical, mechanical, minerals, and chemical. The base layer of physical model testing with the dimension; 2m of length, 2m of width, and 1.5m of height. The addition of lime with variations of 3, 5, 7, an 10%, based on maximum dry density of standard Proctor test results and cured for 28 days. The model of lime treated laterite Halmahera soil with 0,1m thickness placed on subgrade layer with 1,5m thickness. Furthermore, the physical model was given static vertical loading. Some dial gauge is placed on the lime treated soil surface with distance interval 20cm, to read the vertical deformation that occurs during loading. The experimentals data was analyzed and validated with numerical analysis using finite element method. The results showed that the vertical deformation reduced significantly on 10% lime content (three times less than untreated soil), and qualify for maximum deflection (standard requirement L/240) on 7-10% lime content.

stabilization of ikpayongo laterite with cement and calcium carbide

African Journals Online (AJOL)

PROF EKWUEME

the stabilization of soil will ensure economy in road construction, while providing an effective way of disposing calcium carbide waste. KEYWORDS: Cement, Calcium carbide waste, Stabilization, Ikpayongo laterite, Pavement material. INTRODUCTION. Road building in the developing nations has been a major challenge to ...

Effects of fines content on hydraulic conductivity and morphology of laterite soil as hydraulic barrier

Science.gov (United States)

Bello Yamusa, Yamusa; Yunus, Nor Zurairahetty Mohd; Ahmad, Kamarudin; Rahman, Norhan Abd; Sa'ari, Radzuan

2018-03-01

Laterite soil was investigated to find out the effects of fines content and to identify the micro-structural and molecular characteristics to evaluate its potentiality as a compacted soil landfill liner material. Tests were carried out on natural soil and reconstituted soil by dry weight of soil samples to determine the physical and engineering properties of the soil. All tests were carried out on the samples by adopting the British Standard 1377:1990. The possible mechanisms that contributed to the clay mineralogy were analyzed using spectroscopic and microscopic techniques such as field emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX) and X-ray diffractometry (XRD). The laterite soil was found to contain kaolinite as the major clay minerals. A minimum of 50% fines content of laterite soil met the required result for hydraulic barriers in waste containment facilities.

Lateritinga project: a geochemical orientation study for Amazon lateritic

International Nuclear Information System (INIS)

Costa, M.L. da

1990-01-01

The aim of this project is the development of systematic geochemical orientation survey in lateritic weathered terrain, like those form Amazon Region. The main selected targets (sheets) are: Turiacu, Cajuapara and Serra dos Carajas, with 690 samples collected (soils and lateritic rocks). For the Aurizona-Serra do Pirocaua target (Turiacu sheet), within the purpose of this work, 49 samples were collected in a 100x 200m regular grid. From all samples the fraction minor than 200 mesh was taken to analyses (by XRF, AA, OES, ICP and fire assay) for SiO sub(2), Fe sub(2) O sub(3), TiO sub(2), P sub(2) O sub(5), Sr, Ba, Y, Nb, Zr, Ga, Sc, Ni, Co, Cr, Cu, Mn, V, As, Bi, Pt, Pd, Th, Au and REE, as well for their mineralogy by XRD. The chemical results were submitted to statistical treatment with the Geoquant-software for IBM-compatible microcomputer. (author)

Effect of Rice Husk Ash on Cement Stabilized Laterite

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Musa ALHASSAN

2007-09-01

Full Text Available Laterite soil collected from Maikunkele area of Minna, classified as an A-7-6 on AASHTO classification, was stabilized with 2-8% cement by weight of the dry soil. Using British Standard Light (BSL compaction energy, the effect of Rice Husk Ash (RHA on the soil was investigated with respect to compaction characteristics, California Bearing Ratio (CBR and Unconfined Compressive Strength (UCS tests. Results obtained, indicate a general decrease in Maximum Dry Density (MDD and increase in Optimum Moisture Content (OMC, all with increase in RHA Content (2-8% at specified cement contents. There was also a tremendous improvement in the CBR and UCS with increase in the RHA content at specified cement contents to their peak values at between 4-6% RHA. The UCS values also improved with curing age. This indicates the potentials of using 4-6% RHA admixed with less cement contents for laterite soil stabilization.

Effect of clay minerals on the stabilization of black cotton and lateritic soils

International Nuclear Information System (INIS)

Nyambok, I.O.

1986-01-01

The problem associated with black cotton and lateritic soils because of the swelling-shrinkage property of their constituent clay minerals were investigated. Samples of black cotton lateritic soils were collected from different parts of Kenya. The samples were analysed for their mineral compositions and later treated with hydrated lime in order to eliminate the swelling shrinkage behaviour. The samples were subsequently tested for their engineering properties in a soil mechanics laboratory using shear box and Casagrande apparatus. It was found that the chemical treatment of the soils with hydrated lime removes their plastic property and improves their shear strength. (author)

GEOTECHNICAL CHARACTERISTICS OF LATERITIC SOIL STABILIZED WITH SAWDUST ASH-LIME MIXTURES

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Emeka Segun Nnochiri

2017-04-01

Full Text Available This study assesses the geotechnical characteristics of lateritic soil and sawdust ash lime (SDAL mixtures. Preliminary tests were carried out on the natural soil sample for identification and classification purposes. The sawdust was mixed with lime for stabilization in the ratio 2:1. This mixture was thereafter added to the lateritic soil in varying proportions of 2, 4, 6, 8 and 10% by weight of soil. Addition of SDAL increased values of Optimum Moisture Content (OMC from 17.0% at 0% SDAL to 26.5% at 10% SDAL by weight of soil, also, values of Maximum Dry Density (MDD decreased from 2040 kg/m3 at 0% SDAL to 1415 kg/m3 at 10% SDAL. Values of Unconfined Compressive Strength (UCS increased from 38.58 kN/m2 at 0% SDAL to highest value of 129.63 kN/m2 at 6% SDAL. The values of liquid limits and plasticity index of the soil were effectively reduced with the addition of the SDAL, from 54.0% at 0% SDAL to 49.0% at 10% SDAL and from 13.7% at 0% SDAL to 12.5% at 10% SDAL respectively. It was therefore concluded that the sawdust ash lime (SDAL mixture can serve as a cheap soil stabilizing agent for poor lateritic soil.

Multivariate erosion risk assessment of lateritic badlands of Birbhum

Indian Academy of Sciences (India)

Each geomorphic hazard involves a degree of risk which incorporates quantification of the probability that a hazard will be harmful. At present, the categorization of sub-watersheds into erosion risk is considered as the fundamental step to conserve the soil loss. Development of badlands over the laterites of Birbhum district ...

estimation of shear strength parameters of lateritic soils using

African Journals Online (AJOL)

user

... a tool to estimate the. Nigerian Journal of Technology (NIJOTECH). Vol. ... modeling tools for the prediction of shear strength parameters for lateritic ... 2.2 Geotechnical Analysis of the Soils ... The back propagation learning algorithm is the most popular and ..... [10] Alsaleh, M. I., Numerical modeling for strain localization in ...

Geological interpretation of Eastern Cuba Laterites from an airborne magnetic and radioactive isotope survey

Energy Technology Data Exchange (ETDEWEB)

Batista, J.A; Blanco, J [Departamento de Geologia, Instituto Superior Minero Metalurgico de Moa, (Cuba); Perez-Flores, M.A [Centro de Investigacion Cientifica y Educacion Superior de Ensenada, Baja California (Mexico)

2008-04-15

In eastern Cuba area several geophysical techniques have been applied to distinguish the main geological characteristics of the laterites which are of economical importance for the extraction of iron, nickel and chrome. The geophysical measurements include an aeromagnetic survey and thorium (eTh), potassium (K) and uranium (eU) isotope measurements. The results of gamma spectrometer measurements make a distinction between laterite reservoirs. The application of the magnetic and isotope methods allowed the determination of the distribution and development of the laterite crust, as well as the determination of hydrothermal alterations affecting the laterites, which is very useful for mining exploration and exploitation. Such alterations indicate the presence of silicates, which have negative effects on the metallurgic process. It is known that laterite crust has a high content of eU and eTh. [Spanish] Se han utilizado varias tecnicas geofisicas en la region oriental de Cuba para distinguir las principales caracteristicas geologicas de las lateritas, que poseen importancia economica para la extraccion de hierro, niquel y cobalto. Las mediciones geofisicas incluyen un estudio aeromagnetico y mediciones de isotopos de torio (eTh), potasio (K) y uranio (eU). Los resultados de las mediciones espectrometricas establecen diferencias entre los yacimientos de lateritas. De la aplicacion del metodo magnetico e isotopico se determino la distribucion y desarrollo de las cortezas lateriticas, asi como la ubicacion de alteraciones hidrotermales que afectan a las lateritas, lo cual es muy util durante la exploracion y explotacion minera. Esas alteraciones indican la presencia de silicatos, que tienen un efecto negativo en el proceso metalurgico. Se conoce que las cortezas lateriticas tienen altos contenidos de eU y eTh. De los contenidos de eU y eTh se infiere que las lateritas de la region de Moa se formaron antes que las de Mayari. De estas mediciones fue posible inferir el

Extraction of nickel from Ramu laterite by sulphation roasting-water leaching

Science.gov (United States)

Wang, Weiwei; Du, Shangchao; Liu, Guo; Tang, Jianwen; Lu, Yeda; Lv, Dong

2017-08-01

Recovery of nickel from a PNG nickel laterite with high content of iron by a sulphation roasting-water leaching has been studied. The influences of sulfuric acid/ore ratio, temperature of roasting and water on recovery efficiency were investigated. The effective separation of nickel over the co-existed elements including iron was achieved by the process with mixing, curing, roasting and leaching stages. Near 100% of nickel was leached from the roasted laterite by water at 80°C in an atmospheric air, while co-leaching of about 2% of iron, under the optimal pre-treatment conditions with the ratio of acid: ore around 0.45:1 and the roasting temperature about 650°C. The advantages and disadvantages of sulphation atmospheric leaching are compared with pressure acid leaching with engineering consideration.

Effects of corn cob ash on lime stabilized lateritic soil

Science.gov (United States)

Nnochiri, Emeka Segun

2018-03-01

This study assesses the effects of Corn Cob Ash (CCA) on lime-stabilized lateritic soil. Preliminary tests were carried out on the natural soil sample for purpose of identification and classification. Lime being the main stabilizing material was thoroughly mixed with the soil sample to determine the optimum lime requirement of the sample as a basis for evaluating the effects of the CCA. The optimum lime requirement was 10%. The CCA was thereafter added to the lime stabilized soil in varying proportions of 2, 4, 6, 8 and 10%. Unsoaked CBR increased from 83% at 0% CCA to highest value of 94% at 4% CCA. Unconfined Compressive Strength (UCS) values increased from 1123kN/m2 at 0% CCA to highest value of 1180kN/m2 at 4% CCA. It was therefore concluded that CCA can serve as a good complement for lime stabilization in lateritic soil.

Bio-extraction of metal ions from laterite ore by Penicillium ...

African Journals Online (AJOL)

Administrator

2011-09-19

Sep 19, 2011 ... prolonged weathering, laterite soil is produced. Plentiful oxygen .... to wet digestion process by using nitric acid and hydrogen peroxide as described by ... between 1.9 and 3.1, oxalic acid pH ranges from 1.2 to. 2.9, tartaric ...

Effect of rice husk ash on some geotechnical properties of lateritic

African Journals Online (AJOL)

hp

Keywords: Rice Husk Ash (RHA), Lateritic soil, Sub-grade, Maximum Dry ... stabilizing agent (cement or lime) included ... soil and then with distilled water. The clay mineral identification was done using ... California Bearing Ratio (CBR). 22.05.

COMPARATIVE ASSESSMENT OF RICE HUSK ASH, POWDERED GLASS AND CEMENT AS LATERITIC SOIL STABILIZERS

Directory of Open Access Journals (Sweden)

Adebisi Ridwan

2016-10-01

Full Text Available This paper compares the stabilizing effects of three different materials, namely: rice husk ash, powdered glass, and cement on the properties of lateritic soil. The basic properties of the lateritic soil were first obtained through colour, moisture content determination, specific gravity, particle size distribution and Atterberg limits tests. Each of the stabilizing materials was then mixed with the lateritic soil in varying percentages of 2.5%, 5%, 7.5%, 10%, 12.5% and 15% by weight of the soil. Thereafter, compaction and California bearing ratio (CBR tests were carried out on the sample mixes to determine the effects of the materials on the lateritic soil. Chemical tests were also carried out on the samples to determine their percentage oxides composition. The compaction test showed that the highest maximum dry densities (MDD obtained for the mixed samples were 2.32 g/cm3 (at 2.5% cement addition, 2.28g/cm3 (at 5% powdered glass (PG addition and 2.18 g/cm3 (at 5% rice husk ash (RHA addition with corresponding optimum moisture contents (OMC of 10.06%, 14.3% and 12.31% respectively. The CBR tests showed that the CBR values increased in all cases as the materials were added with those of the cement and powdered glass giving the highest values and showing close semblance under unsoaked conditions. The chemical test showed that the significant oxides present in the cement, powdered glass and rice husk ash were CaO (53.60%, SiO2 (68.45% and SiO2 (89.84% respectively.

effect of compactive effort on strength indices of laterite treated

African Journals Online (AJOL)

PROF. BARTH EKWEME

Atterberg's limits test, compaction test, California bearing ratio (CBR) and unconfined ... size, highclay content, and the degree to which the soils have been ... in the stabilization of Ikpayongo laterite with cement. However lime which seems to be the conventional ... as soil modification or stabilization, depending on treatment ...

evaluation of lateritic soil using 2-d electrical resistivity methods at ...

African Journals Online (AJOL)

Global Journal

The purpose of this study is to search for laterite which is of immense economic ... African and South American lithospheric plates (Burke,. 1971). It is bounded on the ... a number of boreholes (Omatsola and Adegoke 1980,. 1981). During the ...

Ferronickel Preparation from Nickeliferous Laterite by Rotary Kiln-Electric Furnace Process

Science.gov (United States)

Li, Guanghui; Jia, Hao; Luo, Jun; Peng, Zhiwei; Zhang, Yuanbo; Jiang, Tao

Nickel is an important strategic metal, which is mainly used for stainless steel production. In the recent years, ferronickel has been used as a substitute for electrolytic nickel for alleviating the cost of stainless steel production. Rotary kiln-electric furnace (RKEF) smelting is currently the world-wide mainstreaming process for ferronickel production from nickeliferous laterite ore, in spite of the high power consumption. In this study, aiming to provide some meaningful guidance for ferronickel production of RKEF smelting, reductive roasting followed by smelting process was carried out. The conditions including reducing parameters (roasting temperature and time) and smelting parameters (coke dosage, CaO dosage, melting temperature and time) were ascertained. The metal recovery ratios, as well as Ni, Fe, S and P content of ferronickel were considered. The results showed that a ferronickel containing 10. 32 wt. % Ni was obtained from a laterite with 1. 85 wt. % Ni, the nickel recovery ratio was about 99%.

Evaluation of Changes in Index Properties of Lateritic Soil Stabilized with Fly Ash

Directory of Open Access Journals (Sweden)

Agapitus AMADI

2010-12-01

Full Text Available For soils to be suitable in civil engineering projects, they must meet existing local requirements for index properties in addition to certain strength criteria. Typically, specifications limit these properties to some threshold values which in most cases are project specific. Some lateritic soils in their natural state need some treatment/modification to meet these specification requirements. The objective of this study was to evaluate changes in the index properties (i.e., particle size distribution, Atterberg limits and compaction characteristics of a residually derived lateritic soil following fly ash application. Lateritic soil – fly ash mixtures with up to 20% fly ash by dry weight of soil were tested and specimens for compaction characteristics were prepared at different compaction states (optimum, dry and wet of optimum moisture content and compacted using British Standard Light (BSL compactive effort. While soil – fly ash mixtures containing up to 15% fly ash classify as CL according to USCS classification system and plotted above A-line in the plasticity chart, it was observed that changes in the gradation characteristics of soil sample treated with 20% fly ash resulted in the alteration of its classification to ML as well as the crossing of the A- line to the silty region. The liquid limit (LL varied from 42.2 to 29.53% representing 70% reduction while the plasticity index (PI of specimen treated with 20% fly ash was 16% lower than that of natural soil. The optimum moisture content (OMC ranged from 17.36% for the natural soil to 18.34% for soil mixtures containing 20% fly ash which yielded dry unit weight of 17.2kN/m3 for the natural soil and 16.1kN/m3 for samples treated with 20% fly ash. From the study, useful data were obtained showing substantial and desirable changes in the properties of lateritic soil as a civil engineering material on application of fly ash.

Nickel distribution and isotopic fractionation in a Brazilian lateritic regolith: Coupling Ni isotopes and Ni K-edge XANES

Science.gov (United States)

Ratié, G.; Garnier, J.; Calmels, D.; Vantelon, D.; Guimarães, E.; Monvoisin, G.; Nouet, J.; Ponzevera, E.; Quantin, C.

2018-06-01

Ultramafic (UM) rocks are known to be nickel (Ni) rich and to weather quickly, which makes them a good candidate to look at the Ni isotope systematics during weathering processes at the Earth's surface. The present study aims at identifying the Ni solid speciation and discussing the weathering processes that produce Ni isotope fractionation in two deep laterite profiles under tropical conditions (Barro Alto, Goiás State, Brazil). While phyllosilicates and to a lower extent goethite are the main Ni-bearing phases in the saprolitic part of the profile, iron (Fe) oxides dominate the Ni budget in the lateritic unit. Nickel isotopic composition (δ60Ni values) has been measured in each unit of the regolith, i.e., rock, saprock, saprolite and laterite (n = 52). δ60Ni varies widely within the two laterite profiles, from -0.10 ± 0.05‰ to 1.43 ± 0.05‰, showing that significant Ni isotope fractionation occurs during the weathering of UM rocks. Overall, our results show that during weathering, the solid phase is depleted in heavy Ni isotopes due to the preferential sorption and incorporation of light Ni isotopes into Fe oxides; the same mechanisms likely apply to the incorporation of Ni into phyllosilicates (type 2:1). However, an isotopically heavy Ni pool is observed in the solid phase at the bottom of the saprolitic unit. This feature can be explained by two hypotheses that are not mutually exclusive: (i) a depletion in light Ni isotopes during the first stage of weathering due to the preferential dissolution of light Ni-containing minerals, and (ii) the sorption or incorporation of isotopically heavy Ni carried by percolating waters (groundwater samples have δ60Ni of 2.20 and 2.27‰), that were enriched in heavy Ni isotopes due to successive weathering processes in the overlying soil and laterite units.

Effects of Palm Kernel Shell Ash on Lime-Stabilized Lateritic Soil

Science.gov (United States)

Nnochiri, Emeka Segun; Ogundipe, Olumide M.; Oluwatuyi, Opeyemi E.

2017-09-01

The research investigated the effects of palm kernel shell ash (PKSA) on lime-stabilized lateritic soil. Preliminary tests were performed on three soil samples, i.e., L1, L2 and L3 for identification; the results showed that L1 was A-7-6, L2 was A-7-6, and L3 was A-7-6. The optimum amount of lime for each of the soil samples was achieved. The optimum amount for L1 was 10%, for L2, 8% and for L3, 10%; at these values they recorded the lowest plasticity indexes. The further addition of PKSA was performed by varying the amount of PKSA and lime added to each of the soil samples. The addition of 4% PKSA+ 6% lime, the addition of 4% PKSA + 4% lime, and the addition of 4% PKSA + 6% lime increased the California Bearing Ratio (CBR) to the highest values for L1, L2 and L3 from 8.20%. It was concluded that PKSA can be a suitable complement for lime stabilization in lateritic soil.

Mobility of gamma-emitting fission products in typical black and laterite soils

International Nuclear Information System (INIS)

D'Souza, T.J.; Mistry, K.B.

1981-01-01

Studies on the movement of the gamma-emitting fission products 106 Ru, 125 Sb, 137 Cs and 144 Ce, surface deposited on columns of the black and laterite soils revealed that the mobility of these nuclides in the two soils depended mainly on the ionic form of the nuclide, soil reaction and predominant clay mineral type in the soil. Results showed a rapid breakthrough of 106 Ru in the black soil and considerable migration to the lower layers in the laterite soil on leaching with rain water, or moderately high calcium or sodium irrigation waters. While near complete fixation of 144 Ce and 137 Cs in the top contaminated layer of both soils was observed, a slight movement of 125 Sb only in the black soil was noticed. Incorporation of organic matter had no effects on the movement of fission products in both soil types, whereas ethylenediaminetraacetic acid (EDTA) induced variable movement of the different radionuclides in the two soil types. (author)

Effect of Rice Husk Ash on Cement Stabilized Laterite

OpenAIRE

Musa ALHASSAN; Alhaji Mohammed MUSTAPHA

2007-01-01

Laterite soil collected from Maikunkele area of Minna, classified as an A-7-6 on AASHTO classification, was stabilized with 2-8% cement by weight of the dry soil. Using British Standard Light (BSL) compaction energy, the effect of Rice Husk Ash (RHA) on the soil was investigated with respect to compaction characteristics, California Bearing Ratio (CBR) and Unconfined Compressive Strength (UCS) tests. Results obtained, indicate a general decrease in Maximum Dry Density (MDD) and increase in Op...

Contribution from coastal laterites to the nearshore placers of central west coast of India

Digital Repository Service at National Institute of Oceanography (India)

Gujar, A.R.; Srinivas, K.

and basalts. The pebbles show genetic relation with the coastal laterites and Deccan trap basalts indicating their derivation from them before the last Holocene transgression. The petrography, mineralogical and geochemical analyses suggest that the minerals...

The effect of smelting time and composition of palm kernel shell charcoal reductant toward extractive Pomalaa nickel laterite ore in mini electric arc furnace

Science.gov (United States)

Sihotang, Iqbal Huda; Supriyatna, Yayat Iman; Ismail, Ika; Sulistijono

2018-04-01

Indonesia is a country that is rich in natural resources. Being a third country which has a nickel laterite ore in the world after New Caledonia and Philippines. However, the processing of nickel laterite ore to increase its levels in Indonesia is still lacking. In the processing of nickel laterite ore into metal, it can be processed by pyrometallurgy method that typically use coal as a reductant. However, coal is a non-renewable energy and have high enough levels of pollution. One potentially replace is the biomass, that is a renewable energy. Palm kernel shell are biomass that can be used as a reductant because it has a fairly high fix carbon content. This research aims to make nickel laterite ores become metal using palm kernel shell charcoal as reductant in mini electric arc furnace. The result show that the best smelting time of this research is 60 minutes with the best composition of the reductant is 2,000 gram.

Elementary and isotopic geochemistry of vein goethite in laterite-gossanic crusts from the Igarape Bahia gold mine (Carajas, Brazil)

International Nuclear Information System (INIS)

Costa, Marcondes Lima da; Schumann, Thomas; Poellmann, Herbert

1996-01-01

The lateritic crusts of the gold mine from the Igarape Bahia, in Carajas, situated at Para state, Brazil, present themselves frequently sectioned by the goethite sub-vertical veins. The veins have the following measures: until 10 cm of thickness and more than 6 m of length. This work aims to characterize the textural, mineralogical and chemical aspects of these veins, in order to understand its evolution, mainly the relation with the laterites and its geological importance, including the aspects referents to the mineral prospecting. (author)

Thermodynamic analysis of the reduction process of Colombian lateritic nickel ore

International Nuclear Information System (INIS)

Diaz, S. C.; Garces, A.; Restrepo, O. J.; Lara, M. A.; Camporredondo, J. E.

2015-01-01

The Colombian nickeliferous laterites are minerals used for the nickel extraction by hydrometallurgical and pyrometallurgical processes. In this work the thermodynamic behaviour of three Colombian lateritic mineral samples are described, with contents of 1.42%, 1.78% y 2.04% of nickel, when they are subjected to the calcination and reduction processes. The mineral was characterized using X Rays Diffraction and X Rays Fluorescence, giving evidence of the presence of mineralogical species such as nepouite (Ni 3 Si 2 O 5 (OH) 4 ), goethite (Fe 2 O 3 .H 2 O), silica (SiO 2 ), antigorite (Mg 3 Si 2 O 5 (OH) 4 ) and fosferite (Mg 2 SiO 4 ). The thermodynamic analysis was conducted using the software HSC Chemistry for Windows 5.1 and was focused in the quantitative determination of the chemical evolution of the mixture of these minerals with variable quantities of coal, in function of temperature. The results produced by the program showed, in the equilibrium, the feasibility of complete reduction of the nickel, and additionally, a considerable high percentage of reduction of iron oxides (up to 99%) using ratio C/O .1 at temperatures close to 1100 degree centigrade. (Author)

Chemical-mineralogical study of the ferrosialitic lateritic profiles in the Teneme, Farallones and Cayo Guam sectors in north east Cuba

International Nuclear Information System (INIS)

Njila, Tendai; Diaz Martinez, Roberto

2016-01-01

The results of a chemical-mineralogical study on the ferrosialitic lateritic weathering profile are presented. Analysis was done using x Ray Fluorescence and Diffraction. The chemical composition of these profile reflects a typical pattern normally observed within such weathering crusts. The sesquioxides of aluminium, iron are concentrated in the upper parts of the profiles as a result of the leaching of alkalis, alkaline-earth elements, and to a lesser extent, silica. Ferrosialitic lateritic profiles formed on Cretaceous and Paleogene islands arcs consist of secondary minerals such as gibbsite, kaolinite, goethite, hematite and montmorillonite, while those associated with basic and volcanogenic-sedimentary rocks of ophiolitic affinity in Cayo Guam are composed of gibbsite and iron oxides. Brings new chemical-mineralogical information on the ferrosialitic lateritic profiles associated with rocks of oceanic nature in north-eastern Cuba, which will help in the exploration for industrial minerals and rocks and their application in industry. (author) [es

Carbothermic Reduction of Nickeliferous Laterite Ores for Nickel Pig Iron Production in China: A Review

Science.gov (United States)

Rao, Mingjun; Li, Guanghui; Jiang, Tao; Luo, Jun; Zhang, Yuanbo; Fan, Xiaohui

2013-11-01

Both the consumption and production of crude stainless steel in China rank first in the world. In 2011, the nickel production in China amounted to 446 kilotons, with the proportion of electrolytic nickel and nickel pig iron (NPI) registering 41.5% and 56.5%, respectively. NPI is a low-cost feedstock for stainless steel production when used as a substitute for electrolytic nickel. The existing commercial NPI production processes such as blast furnace smelting, rotary kiln-electric furnace smelting, and Krupp-Renn (Nipon Yakin Oheyama) processes are discussed. As low-temperature (below 1300°C) reduction of nickeliferous laterite ores followed by magnetic separation could provide an alternative avenue without smelting at high temperature (~1500°C) for producing ferronickel with low cost, the fundamentals and recent developments of the low-temperature reduction of nickeliferous laterite ores are reviewed.

Uranium laterite from Ipora/Amorinopolis region- Goias, Brazil

International Nuclear Information System (INIS)

Fernandes, S.M.

1983-01-01

The present study gives an account of the uranium bearing laterite in the district of Amorinopolis, GO. Emphasis is given in the study of its mineralogy and of the mineralization controls. The uranium mineralization is chiefly found within the arkosic sandstones at the base of the Devonian Ponta Grossa Formation. The ore is tabular and concordant with the bedding, the controls being simultaneously litho-stratigraphic and biochemical. Narrow permeable horizons of arkosic sandstone lie between impermeable shale an siltstone layers. Within the permeable horizon fossil remains (probably brachiopods) are replaced by uranium minerals. The oxidized iron minerals may have acted to insulate and preserve the secondary soluble uranium minerals. (author)

Perilaku Kuat Tekan Tanah Laterit dengan Stabilisasi Kapur dan Semen

OpenAIRE

febriani, fitri

2017-01-01

Laterite soil is a soil that looks like rust color because it contains high iron oxidation. This is not good for infrastructure development, so it needs an innovation as a method of land improvement, that is stabilization. The reinforcement of soil is generally used in a construction to increase the bearing capacity, so it can hold the construction load. The method that frequently used is soil stabilization by the addition of limestone and cement. In this research, the stabilization of clay i...

Improved removal of iodine-125 from effluents by the soil column method using a laterite soil

Energy Technology Data Exchange (ETDEWEB)

Sakuma, S H [Malaysian Inst. for Nuclear Technology Research, Bangi, Selangor (Malaysia)

1997-02-01

The soil column experiments were conducted to treat the liquid wastes from hospitals containing {sup 125}I. Three sorbent samples of laterite clay materials with different content of iron oxides (geothite, {alpha}-FeOOH) and hydroxides were used to sorb anionic iodate. Post-treatment of the liquid wastes with sodium hypochlorite (redox reagent) oxidized the iodide to the desirable iodate ion. pH after treatment ranges between 4.8 to 5.8 that is not very much different from the initial value pH4.5. The results show that 90 to 97% sorption of iodine with the decontamination factor between 10-32 could be obtained after the first two hours of experiments. The concentration has decreased from an initial value of 10 Bq{center_dot}mL{sup -1} to the concentration ranges 0.3 to 0.9 Bq{center_dot}mL{sup -1}. For the soil at pH between 4.5 to 6.0, positive charges predominated on the kaolinite, geothite and aluminum hydroxides. The negative {sup 125}I anions were electrostatically held by the positive charges on the mineral components of the laterite clay materials. The treated effluents could be released to the environment safely after further dilution and decay. The storage period will decrease tremendously providing better management for the disposal of the wastes by generators. The batch experiments conducted using different sorbent masses of soils, show that there was a drop in sorption where the mass of soils falls below approximately between 0 to 0.25 g. The sorption remains constant with the soil mass above 0.25 g. Another batch experiment using different concentration, shows that adsorption capacity of the laterite soil was 1.1 {mu}Ci/g. The adsorption is about 96% with a distribution coefficient of 1170. The experiments conducted show that anionic iodate in the liquid wastes can be removed by the laterite soil material. The column treatment method was more effective, easy to handle, and has low a capital and maintenance cost. (author). 9 refs, 10 figs, 2 tabs.

Interfacial reactions between humic-like substances and lateritic clay: application to the preparation of "geomimetic" materials.

Science.gov (United States)

Goure-Doubi, Herve; Martias, Céline; Lecomte-Nana, Gisèle Laure; Nait-Ali, Benoît; Smith, Agnès; Thune, Elsa; Villandier, Nicolas; Gloaguen, Vincent; Soubrand, Marilyne; Konan, Léon koffi

2014-11-15

The aim of this study was to understand the mechanisms responsible for the strengthening of "geomimetic" materials, especially the chemical bonding between clay and humic substances. The mineral matter is lateritic clay which mainly consists in kaolinite, goethite, hematite and quartz. The other starting products are fulvic acid (FA) and lime. The preparation of these geomimetic materials is inspired from the natural stabilization of soils by humic substances occurring over thousands of years. The present process involves acidic and alkaline reactions followed by a curing period of 18days at 60°C under a water saturated atmosphere. The acceleration of the strengthening process usually observed in soils makes this an original process for treatment of soils. The consolidation of the "geomimetic" materials could result from two major phenomena: (i) chemical bonding at the interface between the clay particles and iron compounds and the functional groups of the fulvic acid, (ii) a partial dissolution of the clay grains followed by the precipitation of the cementitious phases, namely calcium silicate hydrates, calcium aluminate hydrates and mixed calcium silicum and aluminum hydrates. Indeed, the decrease of the BET specific area of the lateritic clay after 24 h of reaction with FA added to the structural reorganization observed between 900 and 1000°C in the "geomimetic" material, and to the results of adsorption measurements, confirm the formation of organo-ferric complexes. The presence of iron oxides in clay, in the form of goethite, appears to be another parameter in favor of a ligand exchange process and the creation of binding bridges between FA and the mineral matter. Indeed all faces of goethite are likely to be involved in complexation reactions whereas in lateritic clay only lateral faces could be involved. The results of the adsorption experiments realized at a local scale will improve our understandings about the process of adsorption of FA on lateritic

Critical metals (REE, Sc, PGE) in Ni laterites from Cuba and the Dominican Republic

Czech Academy of Sciences Publication Activity Database

Aiglsperger, T.; Proenza, J. A.; Lewis, J. F.; Labrador, M.; Svojtka, Martin; Rojas-Purón, A.; Longo, F.; Ďurišová, Jana

2016-01-01

Roč. 73, March 01 (2016), s. 127-147 ISSN 0169-1368 Institutional support: RVO:67985831 Keywords : Caribbean * Cuba * Dominican Republic * Falcondo mining area * Moa Bay mining area * Ni laterite * Platinum Group Elements * Rare Earth Elements * Scandium Subject RIV: DB - Geology ; Mineralogy Impact factor: 3.095, year: 2016

Inorganic polymers from laterite using activation with phosphoric acid and alkaline sodium silicate solution: Mechanical and microstructural properties

Energy Technology Data Exchange (ETDEWEB)

Lassinantti Gualtieri, Magdalena, E-mail: magdalena.gualtieri@unimore.it [Dipartimento di Ingegneria " Enzo Ferrari" , Università degli studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41125 Modena (Italy); Romagnoli, Marcello [Dipartimento di Ingegneria " Enzo Ferrari" , Università degli studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41125 Modena (Italy); Pollastri, Simone; Gualtieri, Alessandro F. [Dipartimento di Scienze Chimiche e Geologiche, Università degli studi di Modena e Reggio Emilia, Via S. Eufemia 19I, I-41121 Modena (Italy)

2015-01-15

Geopolymers from laterite, an iron-rich soil available in developing countries, have great potential as building materials. In this work, laterite from Togo (Africa) was used to prepare geopolymers using both phosphoric acid and alkaline sodium silicate solution. Microstructural properties were investigated by scanning electron microscopy, X-ray powder diffraction and mercury porosimetry, whereas thermal properties were evaluated by thermal analyses. The local environment of iron was studied by X-ray Absorption Spectroscopy (XANES region). The mechanical properties were determined. Modulus of Rupture and Young's modulus fell in the ranges 3.3–4.5 MPa and 12–33 GPa, respectively, rendering the materials good candidates for construction purposes. Heating above 900 °C results in weight-gain, presumably due to iron redox reactions. X-ray Absorption Spectroscopy data evidence changes in the chemical and structural environments of iron following thermal treatment of geopolymers. These changes indicate interaction between the geopolymer structure and iron during heating, possibly leading to redox properties. -- Highlights: •Geopolymerization of laterite is promising for fabrication of building materials. •Both phosphoric acid and alkaline sodium silicate solution can be used for activation. •Thermally activated redox properties of the inorganic polymers were observed.

Inorganic polymers from laterite using activation with phosphoric acid and alkaline sodium silicate solution: Mechanical and microstructural properties

International Nuclear Information System (INIS)

Enzo Ferrari, Università degli studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41125 Modena (Italy))" data-affiliation=" (Dipartimento di Ingegneria Enzo Ferrari, Università degli studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41125 Modena (Italy))" >Lassinantti Gualtieri, Magdalena; Enzo Ferrari, Università degli studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41125 Modena (Italy))" data-affiliation=" (Dipartimento di Ingegneria Enzo Ferrari, Università degli studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41125 Modena (Italy))" >Romagnoli, Marcello; Pollastri, Simone; Gualtieri, Alessandro F.

2015-01-01

Geopolymers from laterite, an iron-rich soil available in developing countries, have great potential as building materials. In this work, laterite from Togo (Africa) was used to prepare geopolymers using both phosphoric acid and alkaline sodium silicate solution. Microstructural properties were investigated by scanning electron microscopy, X-ray powder diffraction and mercury porosimetry, whereas thermal properties were evaluated by thermal analyses. The local environment of iron was studied by X-ray Absorption Spectroscopy (XANES region). The mechanical properties were determined. Modulus of Rupture and Young's modulus fell in the ranges 3.3–4.5 MPa and 12–33 GPa, respectively, rendering the materials good candidates for construction purposes. Heating above 900 °C results in weight-gain, presumably due to iron redox reactions. X-ray Absorption Spectroscopy data evidence changes in the chemical and structural environments of iron following thermal treatment of geopolymers. These changes indicate interaction between the geopolymer structure and iron during heating, possibly leading to redox properties. -- Highlights: •Geopolymerization of laterite is promising for fabrication of building materials. •Both phosphoric acid and alkaline sodium silicate solution can be used for activation. •Thermally activated redox properties of the inorganic polymers were observed

Co-reduction of Copper Smelting Slag and Nickel Laterite to Prepare Fe-Ni-Cu Alloy for Weathering Steel

Science.gov (United States)

Guo, Zhengqi; Pan, Jian; Zhu, Deqing; Zhang, Feng

2018-02-01

In this study, a new technique was proposed for the economical and environmentally friendly recovery of valuable metals from copper smelting slag while simultaneously upgrading nickel laterite through a co-reduction followed by wet magnetic separation process. Copper slag with a high FeO content can decrease the liquidus temperature of the SiO2-Al2O3-CaO-MgO system and facilitate formation of liquid phase in a co-reduction process with nickel laterite, which is beneficial for metallic particle growth. As a result, the recovery of Ni, Cu, and Fe was notably increased. A crude Fe-Ni-Cu alloy with 2.5% Ni, 1.1% Cu, and 87.9% Fe was produced, which can replace part of scrap steel, electrolytic copper, and nickel as the burden in the production of weathering steel by an electric arc furnace. The study further found that an appropriate proportion of copper slag and nickel laterite in the mixture is essential to enhance the reduction, acquire appropriate amounts of the liquid phase, and improve the growth of the metallic alloy grains. As a result, the liberation of alloy particles in the grinding process was effectively promoted and the metal recovery was increased significantly in the subsequent magnetic separation process.

Discovery of Ni-smectite-rich saprolite at Loma Ortega, Falcondo mining district (Dominican Republic): geochemistry and mineralogy of an unusual case of "hybrid hydrous Mg silicate - clay silicate" type Ni-laterite

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Tauler, Esperança; Lewis, John F.; Villanova-de-Benavent, Cristina; Aiglsperger, Thomas; Proenza, Joaquín A.; Domènech, Cristina; Gallardo, Tamara; Longo, Francisco; Galí, Salvador

2017-10-01

Hydrous Mg silicate-type Ni-laterite deposits, like those in the Falcondo district, Dominican Republic, are dominated by Ni-enriched serpentine and garnierite. Recently, abundant Ni-smectite in the saprolite zone have been discovered in Loma Ortega, one of the nine Ni-laterite deposits in Falcondo. A first detailed study on these Ni-smectites has been performed (μXRD, SEM, EPMA), in addition to a geochemical and mineralogical characterisation of the Loma Ortega profile (XRF, ICP-MS, XRD). Unlike other smectite occurrences in laterite profiles worldwide, the Loma Ortega smectites are trioctahedral and exhibit high Ni contents never reported before. These Ni-smectites may be formed from weathering of pyroxene and olivine, and their composition can be explained by the mineralogy and the composition of the Al-depleted, olivine-rich parent ultramafic rock. Our study shows that Ni-laterites are mineralogically complex, and that a hydrous Mg silicate ore and a clay silicate ore can be confined to the same horizon in the weathering profile, which has significant implications from a recovery perspective. In accordance, the classification of "hybrid hydrous Mg silicate - clay silicate" type Ni-laterite deposit for Loma Ortega would be more appropriate.

Understanding the residence of Co in ore minerals - towards the development of novel Co extraction strategies for laterite deposits

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Dybowska, Agnieszka; Norman, Rachel; Schofield, Paul; Herrington, Richard

2017-04-01

Cobalt has unique properties highly valued for many applications essential to the green economy. It has been classified as a critical raw material due to the particularly high risk of supply shortage and its importance for the value chain. Despite low crustal abundance (25ppm), Co is concentrated by various geological processes to concentrations suitable for mining, however the majority of Co is recovered as a by-product of Cu and Ni processing in three principal geological settings: hydrothermal, magmatic and lateritic. Cobalt-rich laterites, which provide 20% of the world's Co, are mainly processed using energy-inefficient pyrometallurgical techniques or high-pressure acid leaching technologies often optimised for extraction of other elements, which can leave between 50 and 80% of the Co unrecovered. In order to develop more efficient Co extraction strategies, understanding the residence of Co in ore minerals is essential. To this end, we are undertaking a detailed mineralogical, chemical and atomistic-scale characterization of Co in samples from a range of laterite deposits. Bulk samples representative of the average ore material were sourced from a variety of undeveloped laterite deposits: Shevchenko (Kazakhstan), Acoje (Philippines), Nkamouna (Cameroon) and Piauí (Brazil). Bulk chemical and mineralogical characterisation was undertaken with ICP-OES/MS and XRD, followed by spatially resolved chemical and mineralogical imaging at the micron scale using µXRD, EPMA, SEM and synchrotron-based µXRF. The chemical state and local environment of Co were determined using X ray spectroscopy (μXANES and μEXAFS). The total concentrations of Co ranged from 630 to 2780 mg/kg. The ore mineral assemblage in the various samples includes goethite, maghemite, hematite, quartz, talc, serpentines, chlorites, smectites, kaolinite and chromites. Manganese oxide minerals are present but, due to their poor crystallinity and low concentration, are not routinely detectable with bulk

EFFECTS OF COMPACTIVE EFFORTS ON GEOTECHNICAL PROPERTIES OF SPENT ENGINE OIL CONTAMINATED LATERITE SOIL

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OLUREMI, J. ROTIMI

2017-03-01

Full Text Available Investigation of the effects of compactive efforts and spent engine oil (SEO contamination on the geotechnical properties of lateritic soils was made. Contaminated specimens were prepared by mixing lateritic soil with up to 10 % SEO by dry weight of the soil in step concentration of 2 % and subjected to geotechnical tests. Results indicated a decrease in the fine content, decrease in liquid limit, maximum dry density (MDD and unconfined compressive strength (UCS with up to 10 % SEO content. No general trend was observed in the optimum moisture content (OMC with increasing SEO content. The MDD, OMC and UCS values increased with increase in the compactive effort. Regression analysis of the results showed that optimum moisture content, fine content and compactive effort significantly influence the soils UCS values. Analysis of variance showed that SEO and compactive effort has significant effect on the parameters with the exception in one case. The results of laboratory tests showed that geotechnical properties of the SEO contaminated soil were immensely impaired.

Effect of pulp density and particle size on indirect bioleaching of Pomalaa nickel laterite using metabolic citric acid

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Petrus, H. B. T. M.; Wanta, K. C.; Setiawan, H.; Perdana, I.; Astuti, W.

2018-01-01

Nickel laterite ore contains oxide of iron, aluminum or both with nickel, cobalt and chromium which can be leached out using hydrometallurgical process. For the purpose of meeting the world’s increasing demand of nickel, there is a need to invent environmentally friendly process to efficiently leach nickel. This experiment used nickel laterite ore obtained from Pomalaa, South Sulawesi. The leaching agent is metabolic citric acid produced by Aspergillus niger under optimum condition. Leaching process was done in three-necked flask in atmospheric temperature and constant stirring speed of 200 rpm. The variable examined in the experiment was pulp density and particle size of nickel laterite ore. Samples were taken at 3, 7, 10, 14, and 17 minutes and then filtered and diluted to be analyzed using ICP-AES. The result of the experiment showed the maximum recovery of metals increase with the decrease of the pulp density. The maximum recovery for varying pulp density were at 5% solid/liquid ratio and the recovery were Ni at 1.63%, Al at 0.47%, Fe at 0.23% and Mg at 1.09%. The effect of particle size on leaching process showed that the leaching process follows the shrinking core model. The maximum recovery of metals at particle size were at 100-120 mesh with Ni at 1.37%, Fe at 0.10%, Al at 0.72% and Mg at 0.62%.

Evaluation of Digital Classification of Polarimetric SAR Data for Iron-Mineralized Laterites Mapping in the Amazon Region

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Cleber G. Oliveira

2013-06-01

Full Text Available This study evaluates the potential of C- and L-band polarimetric SAR data for the discrimination of iron-mineralized laterites in the Brazilian Amazon region. The study area is the N1 plateau located on the northern border of the Carajás Mineral Province, the most important Brazilian mineral province which has numerous mineral deposits, particularly the world’s largest iron deposits. The plateau is covered by low-density savanna-type vegetation (campus rupestres which contrasts visibly with the dense equatorial forest. The laterites are subdivided into three units: chemical crust, iron-ore duricrust, and hematite, of which only the latter two are of economic interest. Full polarimetric data from the airborne R99B sensor of the SIVAM/CENSIPAM (L-band system and the RADARSAT-2 satellite (C-band were evaluated. The study focused on an assessment of distinct schemes for digital classification based on decomposition theory and hybrid approach, which incorporates statistical analysis as input data derived from the target decomposition modeling. The results indicated that the polarimetric classifications presented a poor performance, with global Kappa values below 0.20. The accuracy for the identification of units of economic interest varied from 55% to 89%, albeit with high commission error values. In addition, the results using L-band were considered superior compared to C-band, which suggest that the roughness scale for laterite discrimination in the area is nearer to L than to C-band.

Silicate bonded ceramics of laterites

International Nuclear Information System (INIS)

Wagh, A.S.; Douse, V.

1989-05-01

Sodium silicate is vacuum impregnated in bauxite waste (red mud) at room temperature to develop ceramics of mechanical properties comparable to the sintered ceramics. For a concentration up to 10% the fracture toughness increases from 0.12 MNm -3/2 to 0.9 MNm -3/2 , and the compressive strength from 7 MNm -2 to 30 MNm -2 . The mechanical properties do not deteriorate, when soaked in water for an entire week. The viscosity and the concentration of the silicate solution are crucial, both for the success of the fabrication and the economics of the process. Similar successful results have been obtained for bauxite and lime stone, even though the latter has poor weathering properties. With scanning electron microscopy and energy dispersive analysis, an attempt is made to identify the crystals formed in the composite, which are responsible for the strength. The process is an economic alternative to the sintered ceramics in the construction industry in the tropical countries, rich in lateritic soils and poor in energy. Also the process has all the potential for further development in arid regions abundant in limestone. (author). 6 refs, 20 figs, 3 tabs

Reconstruction of Post-Deccan topographies from mapping of relict lateritic paleosurfaces: Implications for long-term denudation of Peninsular India

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Jean, Amandine; Beauvais, Anicet; Chardon, Dominique; Bonnet, Nicolas; Mudlappa, Jayananda; Janwari, Shazia; Mathé, Pierre-Etienne

2017-04-01

Cenozoic topographic rejuvenation of divergent continental margins and their cratonic hinterland is a matter of debate. For instance, continental scale tilt has been advocated as a cause of Late Cenozoic relief growth of the Indian Peninsula. Our work aims at providing independent geomorphological constraints to test such assertions. The western margin of the Peninsula bears the Western Ghats Escarpment (WGE), which carves both Precambrian rocks and 65 Ma old Deccan Traps. The escarpment separates a narrow coastal lowland plain drained to the Arabian Sea from a highland plateau drained towards the Bengal Sea. Alternating and coupled chemical weathering and erosion led to formation and dissection of lateritic paleolandscapes preserved both sides of the WGE. In the highland, the relicts of three distinctive lateritic surfaces are recognized. They formed successively from 53 Ma to 23 Ma on the basis of ages obtained by Ar-Ar dating of K-rich manganese oxides [1]. The first surface is topped by a duricrust rich in Al (bauxite) forming mesas at altitudes of 960 to 1400 m. The second surface called "Intermediate" is mantled by a ferricrete, whose relicts remain 100 m below the bauxite at altitudes of 850 to 1250 m. The third surface corresponds to the relicts of a lateritic pediment, which may be capped by a ferricrete at altitudes of 600 to 900 m. Three lateritic surfaces have been documented in the lowland. The Ar-Ar ages obtained indicate common lateritic weathering in both the highland and the lowland between at 53-45 Ma, then a divergence later on [1]. The oldest remnants of lateritic surface in the lowland are preserved at maximum elevation of 400-500 m close to the WGE and correspond to a pediment. This ancient landform was re-altered at 24-19 Ma to form residual hills of the "Intermediate" relief (ca. 350-200 m). A younger pediment formed around the residual hills and is preserved at ca. 150-50 m elevation. Relicts' elevations of the three surfaces have been

Mineralogical and geochemical aspects of nickeliferous laterite of Vermelho region, Serra dos Carajas (State of Para)

International Nuclear Information System (INIS)

Almeida Correa, S.L. de.

1982-01-01

Mineralogical and geochemical studies were carried out on the nickeliferous laterite of Vermelho region (Serra of Carajas, state of Para). A total of 64 samples were analysed by X-ray fluorescence analysis and atomic absorption, spectrophotometry, including bed-rock specimens. The laterite is derived from ultramafic rocks (serpentinites) and there horizons were recognized towards the top: saprolitic horizon with a thickness of more than 4 meters, clay horizon 6,1 meters thick and limonitic horizon with a thickness of 8,3 meters. The process of weathering affected both major and trace elements which were bleached, transported and reprecipitated. This caused variations in the concentration of the elements with depth, except for magnesium which was extensively bleached. Nickel concentrations in the clay horizon probably was a result of ion exchange between smectite and Ni-bearing solutions, the source of this Ni being goethite. Cobalt and zinc were also strongly enriched during the process of laterization, although maximum concentrations of these elements are found in different horizons. (author)

Strength Performance Based on Flexibility from Laterite Soil Using Tire Powder and Micro Silica

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Behrouz Gordan

2015-01-01

Full Text Available In terms of environmental issues and human health, one of the advisable techniques to improve soil behavior is the use of scrap tires for soil structures. According to the literature, Tire-Derived Aggregates (TDA are one of the valuable materials in different field of Geotechnical that can be used. TDA properties correspond to some important factors such as high level of flexible, lightweight, high permeability and economic material comparing with sand. Strength performance based on increasing flexibility from laterite soil is the main goal of this study. For this purpose, tropical laterite soil was mixed using TDA and micro silica (MS. As a research method, unconfined tests were carried for thirteen samples based on different percentage of the additives. As a result, the significant reduction for elasticity modulus and strength was observed when soil mixed just using TDA. In addition, the rate of strain at the peak of the curve was dramatically increased. The best performance was found using 6% additives when the ratio was 3% MS and 3% TDA. In fact, the effect of MS was more to increase strength. To recommend, the seepage controlling will investigate at next.

Reactive transport model of the formation of oxide-type Ni-laterite profiles (Punta Gorda, Moa Bay, Cuba)

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Domènech, Cristina; Galí, Salvador; Villanova-de-Benavent, Cristina; Soler, Josep M.; Proenza, Joaquín A.

2017-10-01

Oxide-type Ni-laterite deposits are characterized by a dominant limonite zone with goethite as the economically most important Ni ore mineral and a thin zone of hydrous Mg silicate-rich saprolite beneath the magnesium discontinuity. Fe, less soluble, is mainly retained forming goethite, while Ni is redeposited at greater depth in a Fe(III) and Ni-rich serpentine (serpentine II) or in goethite, where it adsorbs or substitutes for Fe in the mineral structure. Here, a 1D reactive transport model, using CrunchFlow, of Punta Gorda oxide-type Ni-laterite deposit (Moa Bay, Cuba) formation is presented. The model reproduces the formation of the different laterite horizons in the profile from an initial, partially serpentinized peridotite, in 106 years, validating the conceptual model of the formation of this kind of deposits in which a narrow saprolite horizon rich in Ni-bearing serpentine is formed above peridotite parent rock and a thick limonite horizon is formed over saprolite. Results also confirm that sorption of Ni onto goethite can explain the weight percent of Ni found in the Moa goethite. Sensitivity analyses accounting for the effect of key parameters (composition, dissolution rate, carbonate concentration, quartz precipitation) on the model results are also presented. It is found that aqueous carbonate concentration and quartz precipitation significantly affects the laterization process rate, while the effect of the composition of secondary serpentine or of mineral dissolution rates is minor. The results of this reactive transport modeling have proven useful to validate the conceptual models derived from field observations.

Uranium isotope composition of a laterite profile during extreme weathering of basalt in Guangdong, South China

Science.gov (United States)

Huang, J.; Zhou, Z.; Gong, Y.; Lundstrom, C.; Huang, F.

2015-12-01

Rock weathering and soil formation in the critical zone are important for material cycle from the solid Earth to superficial system. Laterite is a major type of soil in South China forming at hot-humid climate, which has strong effect on the global uranium cycle. Uranium is closely related to the environmental redox condition because U is stable at U(Ⅳ) in anoxic condition and U(Ⅵ) as soluble uranyl ion (UO22+) under oxic circumstance. In order to understand the behavior of U isotopes during crust weathering, here we report uranium isotopic compositions of soil and base rock samples from a laterite profile originated from extreme weathering of basalt in Guangdong, South China. The uranium isotopic data were measured on a Nu Plasma MC-ICP-MS at the University of Illinois at Urbana-Champaign using the double spike method. The δ238U of BCR-1 is -0.29±0.03‰ (relative to the international standard CRM-112A), corresponding to a 238U/235U ratio of 137.911±0.004. Our result of BCR-1 agrees with previous analyses (e.g., -0.28‰ in Weyer et al. 2008) [1]. U contents of the laterite profile decrease from 1.9 ppm to 0.9 ppm with depth, and peak at 160 - 170 cm (2.3 ppm), much higher than the U content of base rocks (~0.5 ppm). In contrary, U/Th of laterites is lower than that of base rock (0.27) except the peak at the depth of 160-170 cm (0.38), indicating significant U loss during weathering. Notably, U isotope compositions of soils show a small variation from -0.38 to -0.28‰, consistent with the base rock within analytical error (0.05‰ to 0.08‰, 2sd). Such small variation can be explained by a "rind effect" (Wang et al., 2015) [2], by which U(Ⅳ) can be completely oxidized to U(VI) layer by layer during basalt weathering by dissolved oxygen. Therefore, our study indicates that U loss during basalt weathering at the hot-humid climate does not change U isotope composition of superficial water system. [1] Weyer S. et al. (2008) Natural fractionation of 238U/235

Concentration and Separation of Scandium from Ni Laterite Ore Processing Streams

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Şerif Kaya

2017-12-01

Full Text Available The presence of a considerable amount of scandium in lateritic nickel-cobalt ores necessitates the investigation of possible processing alternatives to recover scandium as a byproduct during nickel and cobalt production. Therefore, in this study, rather than interfering with the main nickel-cobalt production circuit, the precipitation-separation behavior of scandium during a pH-controlled precipitation process from a synthetically prepared solution was investigated to adopt the Sc recovery circuit into an already existing hydrometallurgical nickel-cobalt hydroxide processing plant. The composition of the synthetic solution was determined according to the hydrometallurgical nickel laterite ore processing streams obtained from a HPAL (high-pressure sulphuric acid leaching process. In order to selectively precipitate and concentrate scandium with minimum nickel and cobalt co-precipitation, the pH of the solution was adjusted by CaCO3, MgO, Na2CO3, and NaOH. It was found that precipitation with MgO or Na2CO3 is more advantageous to obtain a precipitate containing higher amounts of scandium with minimum mass when compared to the CaCO3 route, which makes further processing more viable. As a result of this study, it is proposed that by a simple pH-controlled precipitation process, scandium can be separated from the nickel and cobalt containing process solutions as a byproduct without affecting the conventional nickel-cobalt hydroxide production. By further processing this scandium-enriched residue by means of leaching, SX (solvent extraction, and precipitation, an intermediate (NH42NaScF6 product can be obtained.

Clay mineral facies and lateritization in basalts of the southeastern Parana Basin, Brazil

International Nuclear Information System (INIS)

Oliveira, M.T.G. de; Formoso, M.L.L.; Trescases, J.J.; Meunier, A.

1998-01-01

Seventeen samples from two lateritic profiles, each with five facies, were studied. These profiles occur on the old planation surface of the plateau basalts of the southern part of ParanáBasin, Brazil. Optical microscopy, X-ray diffraction, electron microprobe, Mössbauer spectroscopy and Fourier Transform Infrared Spectra were used to obtain information about the nature and chemical composition of each weathering facies. In addition, scanning electron microscopy and analyses of clay minerals were performed to detect microcrystalline environmental changes. Both profiles have two major parts: a loose red-clay latosol separated from an underlying mottled clay and an alterite facies; a stone line may or may not be present between the latosol and the underlying units. In both profiles the latosol consists principally of kaolinite, hematite and goethite. Two alterite facies, shaped by differential weathering, are also present in the lower profile: a halloysite–nontronite clayey matrix with a well developed fissure system occurs in the argillaceous alterite and a network of Al–goethite aggregates is typical of the highly porous cortex of the boulder alterite that is found in the stone line and below it. Gibbsite has crystallized in the large pores of porphyritic boulder alterite but is absent in the small pores of the subaphyric boulder alterite. Clay minerals observed in fissures include halloysite associated with goethite and manganese oxides. The basalt has hydrothermal green-clays (mixed layers and trioctahedral smectites) that formed between primary plagioclase, pyroxene and Ti–magnetite crystals while fresh corestones of the boulder alterite have cryptocrystalline iron-rich material. The study of these profiles shows one principal evolutionary trend for clay minerals. This trend is from smectite and mixed layers that form green clays in altered bedrock at the base of the profile to an intermediate association of nontronite and halloysite in the argillaceous

Effects of Density and Moisture Variation on Dynamic Deformation Properties of Compacted Lateritic Soil

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Weizheng Liu

2016-01-01

Full Text Available A series of repeated load triaxial tests were conducted in this study to investigate the influences of compaction density and postcompaction moisture variation on the dynamic elastic modulus (Ed and plastic permanent strain (PPS of compacted lateritic soil. Specimens were compacted at optimum moisture content (OMC and three degrees of compaction (90%, 93%, and 96%. Then the specimens were dried or wetted to different moisture contents (OMC, OMC±3%, OMC±6%, and OMC+9% prior to testing for Ed and PPS. Results show that moisture content has greater influence on the Ed and PSS than compaction degree, and the increase in moisture content leads to a decrease of Ed and an increase of PPS. Furthermore, an empirical relationship between Ed and applied cyclic stress (σd is developed that incorporates density and moisture variations. Three different evolution types of PPS with number of load cycles, plastic stable, plastic creep, and incremental collapse, are identified as the increase of moisture content. In addition, the critical dynamic stress (σdc separating stable and unstable deformation is determined based on the shakedown concept. The envelope curves of σdc-moisture of lateritic soil with different degrees of compaction are also determined to provide reference for the pavement design.

Degradação das paisagens de solos lateríticos e uso da terra no distrito de Birbhum, Bengala Ocidental, Índia / Degraded lateritic soils cape and land uses in Birbhum District, West Bengal, India

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V. C. Jha

2011-12-01

Full Text Available Degradation of lateritic environment as found in the south western and eastern Birbhum district can be considered as irresistible. Inherently poor physical and chemical status of existing lateritic soil profileand radical conversion of land uses as observed at cadastral level are the key factors of land degradation.Lateritic soilscapes are mostly affected by water erosion induced, vegetal and anthropogenic degradation attaining severe and very severe degradation status. Degraded lands in sample mouzas like Ballabhpur, Shyambati, Chawpahari Jungle, Bodakuri and Pachami account for 60.33%, 71.42%, 72.99%, 87.31% and 79.66% respectively out of their total lateritic exposures. In other words about 36.98%, 71.42%, 61.73%, 56.70% and 76.02% out of their total village areas and mostly non agricultural land use areaffected by it. Four degraded villages get the higher priority for friendly landscape conservation actions.

Effects of reduction temperature to Ni and Fe content and the morphology of agglomerate of reduced laterite limonitic nickel ore by coal-bed method

Science.gov (United States)

Abdul, Fakhreza; Pintowantoro, Sungging; Kawigraha, Adji; Nursidiq, Ahlidin

2018-04-01

As the current drop of nickel sulfide ore on earth, the attention to nickel laterite ore processing was inscreased in order to fulfill the future nickel demand needs. This research aims to optimized the process of nickel laterite ore extraction using coal bed method. This research was conducted by reducing low grade nickel laterite ore (limonitic) with nickel content of 1.25 %. The reduction process was carried out using CO gas which formed by the reaction of coal and dolomite. The Briquette of nickel ore, coal, Na2SO4 mixtures incorporated in the crucible with bed, then reduced for 6 hours at the temperature of 1200 °C. 1400 °C, and 1400 °C. The result of the research shown that the highest increase of Ni content and Ni recovery value was in the reduction temperature of 1400 °C with the increase of 3.44 %, and the recovery value of Ni equal to 86.75 %. While the highest increase of Fe content and Fe recovery value, respectively, was in the reduction temperature of 1300 °C with the increase of 22.67 % and 1200 °C with Fe recovery value of 89.41 %.

Analysis of holding time variations to Ni and Fe content and morphology in nickel laterite limonitic reduction process by using coal-dolomite bed

Science.gov (United States)

Abdul, Fakhreza; Pintowantoro, Sungging; Yuwandono, Ridwan Bagus

2018-04-01

With the depletion of nickel sulfide ore resources, the nickel laterit processing become an attention to fulfill nickel world demans. Reducing laterite nickel by using a low cost carbonaceous reductan has proved produces high grade ferronickel alloy. In this research, reduction was carried out to low grade laterite nickel (limonite) with 1.25% nikel content by using CO gas reductant formed by reaction between coal and dolomite. Reduction process preceded by forming brickets mixture from limonit ore, coal, and Na2SO4, then the brickets placed inside crucible bed together with dolomit and reduced at temperature 1400 °C with holding time variations 4, 6, and 8 hours. EDX, XRD, and SEM test were carried out to find out the Ni and nickel grade after reduced, the phases that formed, and the morphology brickets after reduced. The reduction results shows that the highest increase on nickel grade was obtained by 8 hours holding time increasing 5.84 % from initial grade, and the highest recovery was obtained by 6 hours holding time with recovery 88.51 %. While the higest increase on Fe grade was obtained by 4 hours holding time, and the highest recovery Fe was obtained by 4 hours holding time with recovery 85.41%.

Strontium isotopes reveal weathering processes in lateritic covers in southern China with implications for paleogeographic reconstructions

Science.gov (United States)

Wei, Xiao; Wang, Shijie; Ji, Hongbing; Shi, Zhenhua

2018-01-01

The isotope ratios of Sr are useful tracers for studying parent material sources, weathering processes, and biogeochemical cycling. Mineralogical and geochemical investigations of two lateritic weathering covers, in an area close to the Tropic of Cancer (Guangxi Province, southern China), were undertaken to study the regional weathering processes and Sr isotopic sources. We found that weathering and decomposition of Rb- and Sr-bearing minerals change the Sr isotopic composition in weathering products (lateritic soils). Weathering of illite lowered the 87Sr/86Sr ratio whereas dissolving and leaching of carbonate minerals increased the 87Sr/86Sr ratio. An Fe nodular horizon is widely developed on the top of the weathering covers in the studied area and it differs from the lateritic soil horizon in mineral composition, construction, and elemental concentration. Furthermore, both Fe2O3 and P2O5 (concentrations) are negatively correlated with the 87Sr/86Sr ratios, suggesting fixation of apatite by Fe oxides is a controlling factor of the Sr isotopic composition in the Fe nodular horizon. The 87Sr/86Sr and Nb/Sr ratios imply the contents and proportions of Fe nodules and clay are critical in controlling the changes of Sr isotopic composition in the Fe nodular horizon. The two stages of the weathering process of carbonate rocks are revealed by the87Sr/86Sr versus Nb/Sr diagram. The 87Sr/86Sr and Rb/Sr ratios suggest that Sr isotopes in the weathering covers within the studied area are derived mainly from parent rock weathering and that the contributions from allothogenic Sr isotopes are limited. A comparison of Sr isotopic composition signatures in the weathering covers of the studied area and Guizhou Province provided insight into the Sr isotopic source and paleogeographic evolution of southern China. From the Permian to the Triassic, the continental fragment sources of the South China sedimentary basin changed significantly. In the Permian, Southern China presented the

Strontium isotopes reveal weathering processes in lateritic covers in southern China with implications for paleogeographic reconstructions.

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Xiao Wei

Full Text Available The isotope ratios of Sr are useful tracers for studying parent material sources, weathering processes, and biogeochemical cycling. Mineralogical and geochemical investigations of two lateritic weathering covers, in an area close to the Tropic of Cancer (Guangxi Province, southern China, were undertaken to study the regional weathering processes and Sr isotopic sources. We found that weathering and decomposition of Rb- and Sr-bearing minerals change the Sr isotopic composition in weathering products (lateritic soils. Weathering of illite lowered the 87Sr/86Sr ratio whereas dissolving and leaching of carbonate minerals increased the 87Sr/86Sr ratio. An Fe nodular horizon is widely developed on the top of the weathering covers in the studied area and it differs from the lateritic soil horizon in mineral composition, construction, and elemental concentration. Furthermore, both Fe2O3 and P2O5 (concentrations are negatively correlated with the 87Sr/86Sr ratios, suggesting fixation of apatite by Fe oxides is a controlling factor of the Sr isotopic composition in the Fe nodular horizon. The 87Sr/86Sr and Nb/Sr ratios imply the contents and proportions of Fe nodules and clay are critical in controlling the changes of Sr isotopic composition in the Fe nodular horizon. The two stages of the weathering process of carbonate rocks are revealed by the87Sr/86Sr versus Nb/Sr diagram. The 87Sr/86Sr and Rb/Sr ratios suggest that Sr isotopes in the weathering covers within the studied area are derived mainly from parent rock weathering and that the contributions from allothogenic Sr isotopes are limited. A comparison of Sr isotopic composition signatures in the weathering covers of the studied area and Guizhou Province provided insight into the Sr isotopic source and paleogeographic evolution of southern China. From the Permian to the Triassic, the continental fragment sources of the South China sedimentary basin changed significantly. In the Permian, Southern

In situ neutron moisture meter calibration in lateritic soils

International Nuclear Information System (INIS)

Ruprecht, J.K.; Schofield, N.J.

1990-01-01

An in situ calibration procedure for complex lateritic soils of the jarrah forest of Western Australia is described. The calibration is based on non-destructive sampling of each access tube and on a regression of change in water content on change in neutron count ratio at 'wet' and 'dry' times of the year. Calibration equations with adequate precision were produced. However, there were high residual errors in the calibration equations which were due to a number of factors including soil water variability, the presence of a duricrust layer, soil sampling of gravelly soils and the variability of the cement slurry annulus surrounding each access tube. The calibration equations derived did not compare well with those from other studies in south-west Western Australia, but there was reasonable agreement with the general equations obtained by the Institute of Hydrology, U.K. 15 refs., 6 figs., 2 tabs

Macrofungi in the lateritic scrub jungles of southwestern India

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A. A. Greeshma

2015-09-01

Full Text Available A pilot study on macrofungi in scrub jungles (with and without fire-impact in lateritic region of southwestern coast of India was carried out.  Out of 11 species in 10 genera recovered, six and five species were confined to scrub jungle and fire-impacted scrub jungle, respectively.  An ectomycorrhizal Amanita sp. was the most frequent in scrub jungle associated with exotic (Acacia auriculiformis and A. mangium and plantation (Anacardium occidentale trees.  Based on traditional knowledge, it is a highly edible and nutritional delicacy in the coastal regions.  Astraeus odoratus was another common ectomycorrhizal fungus in native trees Hopea ponga, which was recovered from the fire-impacted scrub jungle and is possibly edible.  Edible termite mound mushroom Termitomyces striatus was also common in the fire-impacted scrub jungle.  Chlorophyllum molybdites was the most frequent mushroom in the fire-impacted scrub jungle.  

The removal of fluoride from aqueous solution by a lateritic soil adsorption: Kinetic and equilibrium studies.

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Iriel, Analia; Bruneel, Stijn P; Schenone, Nahuel; Cirelli, Alicia Fernández

2018-03-01

The use of natural sorbents to remove fluoride from drinking water is a promising alternative because of its low-cost and easy implementation. In this article, fluoride adsorption on a latosol soil from Misiones province (Argentina) was studied regarding kinetic and equilibrium aspects. Experiments were conducted in batch at room temperature under controlled conditions of pH 4-8) and ionic strength (1-10mM KNO 3 ). Experimental data indicated that adsorption processes followed a PSO kinetic where initial rates have showed to be influenced by pH solution. The necessary time to reach an equilibrium state had resulted approximately 30min. Equilibrium adsorption studies were performed at pH 8 which is similar to the natural groundwater. For that, fluoride adsorption data were successfully adjusted to Dubinin-Ataskhov model determining that the fluoride adsorption onto soil particles mainly followed a physical mechanism with a removal capacity of 0.48mgg -1 . Finally, a natural groundwater was tested with laterite obtaining a reduction close to 30% from initial concentration and without changing significantly the physicochemical properties of the natural water. Therefore, it was concluded that the use of lateritic soils for fluoride removal is very promising on a domestic scale. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of Rice Husk Ash on Some Geotechnical Properties of Lateritic Soil

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Fidelis O. OKAFOR

2009-12-01

Full Text Available The study is an investigation into the effect of RHA on some geotechnical properties of a lateritic soil classified as A-2-6 (0 or SW for sub-grade purposes. The investigation includes evaluation of properties such as compaction, consistency limits and strength of the soil with RHA content of 5%, 7.5%, 10% and 12.5% by weight of the dry soil. The results obtained show that the increase in RHA content increased the OMC but decreased the MDD. It was also discovered that increase in RHA content, reduced plasticity and increased volume stability as well as the strength of the soil. 10% RHA content was also observed to be the optimum content.

Genesis of a mottled horizon by Fe-depletion within a laterite cover in the Amazon Basin.

OpenAIRE

Rosolen , Vania; Lamotte , Mathieu; Boulet , René; Trichet , Jean; Rouer , Olivier; José Melfi , Adolpho

2002-01-01

A mottled horizon in a laterite cover (without any duricrust) was studied by microscopy and quantitative chemical microanalysis. Apart from the voids, light red spots consisting of Fe-rich particles (≈2 μm) are set in clayey plasma. Dark red spots consisted of concentrations of Fe-rich particles. These patterns are inherited. On the border of structural or biological voids, where Fe-depletion features are systematic, gray or yellow spots result from dissolution of the Fe-rich particles and im...

Effect of hydrated lime on compressive strength mortar of fly ash laterite soil geopolymer mortar

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Wangsa, F. A.; Tjaronge, M. W.; Djamaluddin, A. R.; Muhiddin, A. B.

2017-11-01

This paper explored the suitability of fly ash, hydrated lime, and laterite soil with several activator (sodium hydroxide and sodium tiosulfate) to produce geopolymer mortar. Furthermore, the heat that released by hydrated lime was used instead of oven curing. In order to produce geopolymer mortar without oven curing, three variations of curing condition has been applied. Based on the result, all the curing condition showed that the hardener mortar can be produced and exhibited the increasing of compressive strength of geopolymer mortar from 3 days to 7 days without oven curing.

Partition of rare-earths in phosphates laterites from Maicuru, Brazil - PA

International Nuclear Information System (INIS)

Lemos, V.P.; Costa, M.L. da.

1987-01-01

The phosphatic laterites of Maicuru-Para are formed of aluminium phosphates, mainly of the crandallite group, followed by wardite, augellite and senegallite. The crandallite group is represented in the form of the solid solution goyazite-florencite-crandallite, in variable proportions. In three samples, the florencite occurs as the predominant member, while in the others crandallite is the main mineral. The unit-cell dimension of florencites, in two samples, measured are the same as those of the florencites from other deposits. The rare earths occur mainly in this mineral group with predominance of the light rare earth elements. This is well observed in the condrite normalized REE patterns. These enrichments are not regular. The geochemical characteristics of the rare earth distribution in the crandallites of Maicuru, leads tho suggest this mineral was formed from distinct lithologies. (author) [pt

Geochemical behaviour of U3O8, Mo, Y, Ga, V and Zr in laterite - bauxitic sequence of the ''Croanta-Paragominas''

International Nuclear Information System (INIS)

Ferraioli, R.N.M.; Ferreira, Z.C.A.

1987-10-01

Fifteen samples are studied, analyzed for U 3 O 8 (delayed neutrons), ThO 2 (X-ray fluorescence spectrometry) and Mo, Y, Ga, V and Zr (optical emission spectrography) in laterite - bauxitic sequence of the Paragominas, Brazil. Generical datas about the arrangements of thorium, uranium and zirconium are also presented. (C.G.C.) [pt

Mineralized lateritic profile in Sn, Zr, Th, Nb, Y and ETR (Serra do Madeira - Pitinga - AM): mineralogical characteristics and geochemical evolution

International Nuclear Information System (INIS)

Horbe, Adriana M.C.; Costa, Marcondes L. da

1997-01-01

The Pitinga region is located in the north 250 km far from Manaus, in the Amazonas State, Brazil. The Serra do Madeira is the local name of one hill located in the Madeira granite with important primary and supergenic mineralizations of Sn (cassiterite), Zr (zircon), Th (thorite), Nb (columbite and pyroclore), Y and REE (xenotime). The Serra do Madeira was constituted by a lateritic profile with 20 m of thickness where were identified seven horizons: parent rock, saprolite, clayey, bauxitic, concretionary, coluvion and latosol. The lateritization promoted the chemistry instability of the parent-rock forming a clayey material where Al 2 O 3 , Fe 2 O 3 , Sn, Th and Nb were enriched as kaolinite, gibbsite, hematite, goethite, cassiterite, zircon, thorite and columbite; SiO 2 , FeO, CaO, Na 2 O, K 2 O, F, Pb, Rb, and U were leached as quartz, K-feldspar, plagioclase, riebeckite/arfvedsonite, biotite, and iron sulfides; Y, P and ETR were enriched and leached correlated to xenotime, bastnaesite, fluorcerite and probably churchite and ytriofluorite

Modeling thermal performance of exterior walls retrofitted from insulation and modified laterite based bricks materials

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Wati, Elvis; Meukam, Pierre; Damfeu, Jean Claude

2017-12-01

Uninsulated concrete block walls commonly found in tropical region have to be retrofitted to save energy. The thickness of insulation layer used can be reduced with the help of modified laterite based bricks layer (with the considerably lower thermal conductivity than that of concrete block layer) during the retrofit building fabrics. The aim of this study is to determine the optimum location and distribution of different materials. The investigation is carried out under steady periodic conditions under the climatic conditions of Garoua in Cameroon using a Simulink model constructed from H-Tools (the library of Simulink models). Results showed that for the continuous air-conditioned space, the best wall configuration from the maximum time lag, minimum decrement factor and peak cooling transmission load perspective, is dividing the insulation layer into two layers and placing one at the exterior surface and the other layer between the two different massive layers with the modified laterite based bricks layer at the interior surface. For intermittent cooling space, the best wall configuration from the minimum energy consumption depends on total insulation thickness. For the total insulation thickness less than 8 cm approximately, the best wall configuration is placing the half layer of insulation material at the interior surface and the other half between the two different massive layers with the modified earthen material at the exterior surface. Results also showed that, the optimum insulation thickness calculated from the yearly cooling transmission (estimated only during the occupied period) and some economic considerations slightly depends on the location of that insulation.

Validity of using modified capillary column with larger diameter to study the Cs diffusion in local Taiwan laterite

International Nuclear Information System (INIS)

Tsing-Hai Wang; National Tsing Hua University, Hsinchu, Taiwan; Wen-Chun Yeh; Shih-Chin Tsai; Yi-Lin Jan; Shi-Ping Teng

2008-01-01

We have examined the working diameter of capillary columns with diameter of 5, 7, 10 and 20 mm. These modified capillary columns were carefully filled with local Taiwan laterite (LTL). The porosity and density of these packed columns was 0.51±0.02 g/g and 1.27±0.05 g/cm 3 , respectively. The diffusion experiments were then carried out in synthetic groundwater with Cs loading of 0.1mM at room temperature. Experimental results have shown that the diffusion profiles of modified capillary columns fit Fick's second law very well. This result revealed that the working diameter of a capillary column can be expanded to at least to 20 mm without affecting the validity of the derived diffusion coefficients. Among these columns, the ones with 5 mm diameter show the most consistent results of the derived K d , apparent and effective diffusion coefficients. Although the derived distribution and effective diffusion coefficients slightly decrease as the diameter of these columns increases due to the increase of the solid/liquid ratio. These values are still informative of the Cs diffusion in local Taiwan laterite. Moreover, our results clearly demonstrate the potential of using 'modified capillary method' to study the diffusion behaviors of concerned radionuclide because columns with large diameter enable the filling with more versatile geological substances. (author)

Morphology and composition of gold in a lateritic profile, Fazenda Pison “Garimpo”, Amazon, Brazil

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Larizzatti, J. H.; Oliveira, S. M. B.; Butt, C. R. M.

2008-05-01

This study describes the morphological evolution of gold grains in a lateritic weathering profile in an equatorial rainforest climate. Primary sources of gold are quartz veins associated with shallow granophyric intrusion. Gold grains were found in fresh ore, saprolite, transition zones, ferruginous duricrust, red latosol, and yellow latosol. Irregularly shaped grains predominate, with smaller proportions of dendritic and prismatic forms. Gold grains are weathered in the uppermost 10 m of the regolith. Mean gold grain size is maximum in the duricrust (>125 μm) and decreases progressively upward into the yellow latosol (duricrust formation may preserve some grains as large aggregates, but subsequent transformation into latosol further modifies them.

Moessbauer study of the evolution of a laterite iron mineral based catalyst: effect of the activation treatment

International Nuclear Information System (INIS)

Cubeiro, M.L.; Goldwasser, M.R.; Perez Zurita, M.J.; Franco, C.; Gonzalez-Jimenez, F.; Jaimes, E.

1994-01-01

The syngas reaction has been studied using a laterite iron mineral, promoted with K and Mn. In situ activation under syngas, as well as pre-treatment with H 2 followed by CO under mild and more severe conditions were tested. These activation procedures led to different iron phase compositions and to different catalytic selectivities. The C 2 -C 4 /CH 4 ratio was significantly lower for those catalysts which after reaction showed the presence of hexagonal carbide and magnetite compared to the solid, which showed the highest proportion of Haegg carbide. (orig.)

Effect of the use nickeliferous laterite and pumice as additives in the performance and durability of the Portland cement

OpenAIRE

Rueda-Gualdrón, María Carolina; Vega-Nuñez, Karen Milena; Ríos-Reyes, Carlos Alberto

2016-01-01

This work evaluated the pozzolanic behavior of the niqueliferous laterite of Cerromatoso (Córdoba) and the pumice of Cemex (Boyacá), based on the NTC standards for fine aggregates. The mortars were prepared with additions of 2.5%, 5% and 10% as substitutes of type I Portland cement, which tested to extreme environments (high temperatures and chemical attacks with H2SO4 y MgSO4). Results demonstrates how these alternative materials increase or decrease their puzolanic degree, as well as the ef...

Existing Versus Added Soil Organic Matter in Relation to Phosphorus Availability on Lateritic Soils

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Fadly Hairannoor Yusran

2008-01-01

Full Text Available Lateritic soils (Ultisols and Oxisols are commonly characterised by high phosphate sorbing capacity due to the type of clay and present high content of aluminium (Al and iron (Fe oxides. Addition of fresh organic matter (OM may contribute to management of these soils by releasing more bicarbonate-extractable phosphorus (BP through organic phosphorus (OP transformation, or by the soluble component of OM additions desorbing phosphate by ligand exchange. It is not known, however, whether BP results solely from addition of new OM (by either mineralisation or desorption or from transformation of inherent or pre-existing in soil. We considered that removing the existing soil OM and replacing it with an equivalent amount of new OM may help to resolve this issue, especially with respect to P transformation after OM additions. Three lateritic soils of Western Australia (including a deep regolith material with very low inherent soil OM (SOM were used, and sub-samples of the three soils were combusted (450° C to obtain soils effectively free from existing OM. A further sub-sample of the soils was not combusted. Both soil groups, receiving the same amount of organic carbon (OC, from 80 ton ha-1 biomass + soil OM or biomass equal to soil OM from peat, wheat straw (Triticum aestivum L. and lucerne hay (Medicago sativa L., were incubated for nine months. Soil bicarbonate-extractable P as well as non-extractable P (NP, measured as Total-P (TP-BP increased due to new OM application in the order lucerne hay>peat>wheat straw. The correlation between BP with soil organic carbon (SOC became more positive over time. Microbial biomass phosphorus (MBP was not well correlated with the increase of NP content and phosphatase was not related to the increase in BP. Overall, freshly applied (new OM not only contributed to the increased level of P compared with the existing OM treatment.

Hydrogeologic and hydraulic characterization of aquifer and nonaquifer layers in a lateritic terrain (West Bengal, India)

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Biswal, Sabinaya; Jha, Madan K.; Sharma, Shashi P.

2018-02-01

The hydrogeologic and hydraulic characteristics of a lateritic terrain in West Bengal, India, were investigated. Test drilling was conducted at ten sites and grain-size distribution curves (GSDCs) were prepared for 275 geologic samples. Performance evaluation of eight grain-size-analysis (GSA) methods was carried out to estimate the hydraulic conductivity (K) of subsurface formations. Finally, the GSA results were validated against pumping-test data. The GSDCs indicated that shallow aquifer layers are coarser than the deeper aquifer layers (uniformity coefficient 0.19-11.4). Stratigraphy analysis revealed that both shallow and deep aquifers of varying thickness exist at depths 9-40 and 40-79 m, respectively. The mean K estimates by the GSA methods are 3.62-292.86 m/day for shallow aquifer layers and 0.97-209.93 m/day for the deeper aquifer layers, suggesting significant aquifer heterogeneity. Pumping-test data indicated that the deeper aquifers are leaky confined with transmissivity 122.69-693.79 m2/day, storage coefficient 1.01 × 10-7-2.13 × 10-4 and leakance 2.01 × 10-7-34.56 × 10-2 day-1. Although the K values yielded by the GSA methods are generally larger than those obtained from the pumping tests, the Slichter, Harleman and US Bureau Reclamation (USBR) GSA methods yielded reasonable values at most of the sites (1-3 times higher than K estimates by the pumping-test method). In conclusion, more reliable aquifers exist at deeper depths that can be tapped for dependable water supply. GSA methods such as Slichter, Harleman and USBR can be used for the preliminary assessment of K in lateritic terrains in the absence of reliable field methods.

Uptake, distribution and metabolic fate of 59Fe, 58Co, 54Mn and 65Zn in plants and their mobility and availability to crops in typical black and laterite soils

International Nuclear Information System (INIS)

D'Souza, T.J.; Mistry, K.B.

1979-01-01

Studies were undertaken on typical soils of India. Nutrient culture experiments indicated that with identical plant growth periods the accumulation in aerial tissues of 65 Zn and 54 Mn was greater than that of 58 Co and 59 Fe. The distribution of 59 Fe, 58 Co and 65 Zn in the various aerial organs of bean plants was generally uniform whereas the distribution of 54 Mn followed an acropetal gradient. The chemical association of 59 Fe, 58 Co and 65 Zn in the edible bean pods was predominantly with lipids and ionic forms whereas 54 Mn association was mainly with ionic forms. The plant uptake of these radionuclides from typical black and laterite soils showed maximum accumulation of 54 Mn followed by 65 Zn, 59 Fe and 58 Co in both soil types and the uptake was greater from the laterite soil than from the black soil. Flooding treatment of rice, while showing a reduction of 59 Fe uptake, showed an increase in plant uptake of 58 Co, 54 Mn and 65 Zn in both soil types. Organic matter addition resulted in a significant reduction of 59 Fe and 58 Co in the laterite soil and of 65 Zn in the black soil. All the four nuclides were completely immobile in the two soil types when leached with rain water or irrigation waters or when treated with organic matter. However, leaching with 10 -2 M EDTA solution induced a rapid breakthrough of all the four radionuclides. (author)

Corrigendum to “Comparing activated alumina with indigenous laterite and bauxite as potential sorbents for removing fluoride from drinking water in Ghana” [Appl. Geochem. 56 (2015) 50–66

Science.gov (United States)

Craig, Laura; Stillings, Lisa; Decker, David L.; Thomas, James M.

2015-01-01

The authors regret that the application of the t-plot to determine the presence of micropores in the three sorbents needs the following corrections: (1) Fig. 1a, c, e are N2(g) adsorption and desorption isotherms” (remove “BET”). This correction applies to descriptions in the text as well. (2) Table 2, the column titled “Micropores” is mislabelled, and should be labelled “Film thickness”, which may not equal the pore width. The column titled “Micropore volume” is a correct description for laterite volume 0.0022 cm3 g−1 (t = 0.3–0.5 nm), but the other pore volumes listed cannot be identified as corresponding to micropores. They likely comprise both micropores and mesopores in laterite, while the presence of micropores in activated alumina is not clear. The positive y-intercept for the lowest linear portion of the laterite t-plot curve indicates micropores (Fig. 1f), and the shape of the t-plot curve suggests the presence of both micropores and mesopores. The shape of the activated alumina t-plot curve suggests the presence of micropores and mesopores, but the zero intercept for the lowest linear portion of the curve (Fig. 1b) creates uncertainty regarding the presence of micropores. Also see Storck et al., 1998; Hay et al. 2011 and references therein. (Additional note: analytical instrument Micromeritics® was misspelled as “Micrometrics”).The authors would like to apologise for any inconvenience caused.

Fe-Ni-bearing serpentines from the saprolite horizon of Caribbean Ni-laterite deposits: new insights from thermodynamic calculations

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Villanova-de-Benavent, Cristina; Domènech, Cristina; Tauler, Esperança; Galí, Salvador; Tassara, Santiago; Proenza, Joaquín A.

2017-10-01

Fe-Ni-bearing serpentine from the saprolite horizon is the main Ni ores in hydrous silicate-type Ni laterites and formed by chemical weathering of partially serpentinized ultramafic rocks under tropical conditions. During lateritization, Mg, Si, and Ni are leached from the surface and transported downwards. Fe2+ is oxidized to Fe3+ and fixed as insoluble Fe-oxyhydroxides (mostly goethite) that incorporate Ni. This Ni is later leached from goethite and incorporated in secondary serpentine and garnierite. As a result, a serpentine-dominated saprolite horizon forms over the ultramafic protolith, overlapped by a Fe-oxyhydroxide-dominated limonite horizon. The serpentine from the protolith (serpentine I) is of hydrothermal origin and yields similar Ni (0.10-0.62 wt.% NiO) and lower Fe (mostly 1.37-5.81 wt.% FeO) concentrations than the primary olivine. In contrast, Fe-Ni-bearing serpentine from the saprolite (serpentine II) shows significantly higher and variable Fe and Ni contents, typically ranging from 2.23 to 15.59 wt.% Fe2O3 and from 1.30 to 7.67 wt.% NiO, suggesting that serpentine get enriched in Fe and Ni under supergene conditions. This study presents detailed mineralogical, textural, and chemical data on this serpentine II, as well as new insights by thermodynamic calculations assuming ideal solution between Fe-, Ni- and Mg-pure serpentines. The aim is to assess if at atmospheric pressure and temperature Fe-Ni-bearing serpentine can be formed by precipitation. Results indicate that the formation of serpentine II under atmospheric pressure and temperature is thermodynamically supported, and pH, Eh, and the equilibrium constant of the reaction are the parameters that affect the results more significantly.

Biocatalytic and chemical leaching of a low-grade nickel laterite ore

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Ciftci, Hasan; Atik, Suleyman; Gurbuz, Fatma

2018-04-01

Nickel and cobalt recovery from a low-grade nickel laterite ore, supplied from Çaldağ deposit (Manisa, Turkey) were investigated by bio and chemical leaching processes. The fungus, Aspergillus niger was used for biocatalytic leaching experiments. The effects of parameters (solid ratio and sucrose concentration) on the biocatalytic leaching of the ore were initially tested in flasks to obtain the optimum conditions for the A. niger. Then chemical leaching was applied as a comparison to bioleaching, using organic acids (citric, oxalic, acetic and gluconic acids) as well as a mixture of acids. According the results, the maximum dissolution yield of nickel, cobalt and iron were detected respectively as 95.3%, 74.3% and 50.0% by biocatalytic processes which containing 25% (w/v) sucrose and 1% (w/v) solids. The increase in the solid ratio adversely influenced the biocatalytic activity of A. niger. Finally, further tests in reactors (v = 1 and 10 L) were performed using the optimum conditions from the flask tests. The difference in metals recovery between biocatalytic and chemical leaching was significantly important. Bioleaching produced higher Ni and Co extractions (34.3-75.6%) than chemical process.

Assessing the 2D Models of Geo-technological Variables in a Block of a Cuban Laterite Ore Body. Part IV Local Polynomial Method

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Arístides Alejandro Legrá-Lobaina

2016-10-01

Full Text Available The local polynomial method is based on assuming that is possible to estimate the value of a U variable in any of the P coordinate through local polynomials estimated based on approximate data. This investigation analyzes the probability of modeling in two dimensions the thickness and nickel, iron and cobalt concentrations in a block of Cuban laterite ores by using the mentioned method. It was also analyzed if the results of modeling these variables depend on the estimation method that is used.

Rare earth element mineralogy and geochemistry in a laterite profile from Madagascar

International Nuclear Information System (INIS)

Berger, Alfons; Janots, Emilie; Gnos, Edwin; Frei, Robert; Bernier, Felix

2014-01-01

Highlights: • Secondary REE-mineralogy depend on redox conditions inside a laterite. • Detailed mineralogy in different layers of a laterite is given. • A Gd-sulfate is described. • Change in bulk rock chemistry control REE mineralogy. - Abstract: In this study, rare earth element (REE) distribution has been investigated in a weathering profile from central Madagascar. Combination of bulk rock geochemical data (elements and isotopes) with mineral characterization reveals a remarkable evolution of the REE abundances and REE-minerals in the vertical weathering profile. In the fresh tonalite (bedrock), REE + Y concentrations are typical of granitoids (299–363 ppm) and the main REE-minerals are allanite and chevkinite. In the C-horizon (saprolite), primary REE-minerals disappear and REEs are transported via fluid to precipitate rhabdophane group minerals in cracks and pores. The presence of sulfate ligands, produced by sulfide oxidation, may be responsible for the REE speciation, as suggested by the composition of the secondary REE-minerals. Rhabdophane group minerals contain up to 9 wt% SO 3 and 7 wt% CaO, indicating a mixture between rhabdophane sensu stricto, (REE)PO 4 ·H 2 O, and tristamite, (Ca,U,Fe (III) )(PO 4 ,SO 4 )·2H 2 O. Due to intense Ca-leaching, rhabdophane disappears and Al-phosphates (alunite–jarosite group) are found in the soil. Cerianite (Ce (IV) O 2 ) also precipitates in the B-horizon of the soil. Mass transfer calculations based on immobile Ti indicate significant REE leaching in A-horizon with preferential leaching of the heavy REE. REEs accumulate partly in the B-horizon. The uniform Nd isotope compositions and the constant proportion of immobile elements do not reveal external input. In the B-horizon, total REE + Y reach 2194 ppm with high Ce concentrations (1638 ppm; 9 * Ce bedrock ) compared to other REE (3–4 * REE bedrock ). Tetravalent Ce state is dominant in the B-horizon and requires oxidizing conditions that likely

Platinum-Group Minerals in Chromitites of the Niquelândia Layered Intrusion (Central Goias, Brazil: Their Magmatic Origin and Low-Temperature Reworking during Serpentinization and Lateritic Weathering

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Nelson Angeli

2012-10-01

Full Text Available A variety of platinum-group-minerals (PGM have been found to occur associated with the chromitite and dunite layers in the Niquelândia igneous complex. Two genetically distinct populations of PGM have been identified corresponding to phases crystallized at high temperatures (primary, and others formed or modified during post-magmatic serpentinization and lateritic weathering (secondary. Primary PGM have been found in moderately serpentinized chromitite and dunite, usually included in fresh chromite grains or partially oxidized interstitial sulfides. Due to topographically controlled lateritic weathering, the silicate rocks are totally transformed to a smectite-kaolinite-garnierite-amorphous silica assemblage, while the chromite is changed into a massive aggregate of a spinel phase having low-Mg and a low Fe3+/Fe2+ ratio, intimately associated with Ti-minerals, amorphous Fe-hydroxides, goethite, hematite and magnetite. The PGM in part survive alteration, and in part are corroded as a result of deep chemical weathering. Laurite is altered to Ru-oxides or re-crystallizes together with secondary Mg-ilmenite. Other PGM, especially the Pt-Fe alloys, re-precipitate within the altered chromite together with kaolinite and Fe-hydroxides. Textural evidence suggests that re-deposition of secondary PGM took place during chromite alteration, controlled by variation of the redox conditions on a microscopic scale.

Bioleaching of nickel by Aspergillus humicola SKP102 isolated from Indian lateritic overburden

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Suchhanda Ghosh

2016-01-01

Full Text Available The lateritic deposits spread over the Eastern Ghats of Sukinda Valley, Odisha, India, produce a huge amount of overburden annually as a byproduct of chromite mining. This chromite mining overburden contains nickel, the only source of the metal in the country. During this study Aspergillus humicola SKP102, an indigenous fungus isolated from the mining overburden was employed for the leaching of nickel. About 53.89% of the nickel could be leached by the fungus when grown in batch mode using a Czapek dox medium containing 2% (w/v of the mining overburden. The parameters affecting bioleaching were optimized in order to grow the fungus and leach the metal. Of the different options of cheap carbon sources, straw infusion and molasses emerged as viable options for the growth of the fungus and the leaching of nickel. Two-step and indirect techniques were also used for this purpose, and they resulted in 53.09% and 65.04% Ni leaching respectively. Adding diluted sulfuric acid to the leaching medium resulted in 97.05% nickel recovery from the overburden pulp. A. humicola SKP102 could be a potential tool for leaching nickel from the mining overburden.

The potential use of rainwater as alternative source of drinking water by using laterite soil as natural adsorbent

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Omar, Khairunnisa Fakhriah Mohd; Palaniandy, Puganeshwary; Adlan, Mohd Nordin; Aziz, Hamidi Abdul; Subramaniam, Ambarasi

2017-10-01

Generally, the rainwater has low concentration of pollutants, whereby it is applicable for domestic water supply. Due to the low concentration of pollutants, further treatment such as adsorption is necessary to treat the harvested rainwater as an alternative source of drinking water supply. Therefore, this research has been carried out to determine the quality of rainwater from different types of locations, which are; rural residential area, urban residential area, agricultural area, industrial area, and open surface. The rainwater sampling was carried out from September 2014 to December 2015. The parameters that have been analysed during the sampling process are chemical oxygen demand (COD), turbidity, heavy metals, and Escherichia coli (E.coli). The sampling results show that the rainwater provides low concentration of contaminants. Thus, it has high potential to be used as alternative source of potable and non potable water supply with a suitable treatment. Due to that, an experimental work contained of 86 of designated experiments for a batch study has been carried out to determine the performance of laterite soil as an adsorbent to remove pollutants that present in the rainwater (i.e. zinc, manganese, and E.coli). The operating factors involved in the experimental works are pH, mass of adsorbents, contact time, initial concentration of zinc, manganese, and E.coli. In this study, the experimental data of the batch study was analysed by developing regression model equation and analysis of variance. Perturbation plots were analysed to determine the effectiveness of the operating factors by developing response surface model, resulting that the high removals of zinc, manganese, and E.coli are 95.8%, 94.05% and 100%, respectively. Overall, this research works found out that the rainwater has a good quality as alternative source of drinking water by providing a suitable treatment. The application of laterite soil as natural adsorbent shows that it has potential to be

Effect of nonwoven jute agrotextile mulch on soil health and productivity of broccoli (Brassica oleracea L.) in lateritic soil.

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Manna, Koushik; Kundu, Manik Chandra; Saha, Biplab; Ghosh, Goutam Kumar

2018-01-16

A field experiment was conducted in winter season of 2015-2016 in the dry lateritic soil of Eastern India to study the effect of different thicknesses of nonwoven jute agrotextile mulches (NJATM) along with other mulches on soil health, growth and productivity of broccoli (Brassica oleracea L.). The experiment was conducted in randomized block design with six treatments viz., T 1 (control, i.e. no mulching), T 2 (300 gsm NJATM), T 3 (350 gsm NJATM), T 4 (400 gsm NJATM), T 5 (rice straw) and T 6 (black polythene mulch), each of which was replicated four times. The highest average curd weight (355.25 g) and yield (8.53 t ha -1 ) of broccoli were recorded in T 3 treatment. The lowest density of broad leaved weed, sedges and grasses were recorded in T 6 treatment which was statistically at par with T 4 . All the treatments composing of NJATM increased the population of all the soil microbes except bacteria in the root rhizosphere of broccoli from their initial population. On average, the highest population of fungi (54.0 × 10 3  cfu per g) and actinomycetes (134.75 × 10 3  cfu per g) was recorded with T 3 and T 4 treatments respectively in the post-harvest soil. The soil moisture was conserved in all treatments compared to control showing highest moisture content in T 4 treatment. Organic carbon and available N, P and K contents of soil were increased in all mulch treated plots compared to control, and their initial value and their highest value were recorded in T 3 . The NJATM of 350 gsm thickness was very effective compared to other mulches in increasing the growth and productivity of broccoli by suppressing weeds, increasing moisture, microbial population and nutrient content of the lateritic soil.

Effects of simulated acid rain on microbial characteristics in a lateritic red soil.

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Xu, Hua-qin; Zhang, Jia-en; Ouyang, Ying; Lin, Ling; Quan, Guo-ming; Zhao, Ben-liang; Yu, Jia-yu

2015-11-01

A laboratory experiment was performed to examine the impact of simulated acid rain (SAR) on nutrient leaching, microbial biomass, and microbial activities in a lateritic red soil in South China. The soil column leaching experiment was conducted over a 60-day period with the following six SAR pH treatments (levels): 2.5, 3.0, 3.5, 4.0, 4.5, and 5.0 and one control treatment (pH = 7). Compared with the control treatment, the concentrations of soil organic matter, total nitrogen, total phosphorus, total potassium, soil microbial biomass carbon (MBC), soil microbial biomass nitrogen (MBN), and average well color density (AWCD) in the Ecoplates were all significantly decreased by leaching with SAR at different pH levels. The decrease in MBC and MBN indicated that acid rain reduced the soil microbial population, while the decrease in AWCD revealed that acid rain had a negative effect on soil bacterial metabolic function. Soil basal respiration increased gradually from pH 4.0 to 7.0 but decreased dramatically from pH 2.5 to 3.0. The decrease in soil nutrient was the major reason for the change of soil microbial functions. A principal component analysis showed that the major carbon sources used by the bacteria were carbohydrates and carboxylic acids.

Development and application of an instrument for analysis of iron in laterite ore with the characteristics needed for use in nickel production. Part of a coordinated programme on on-line X-ray and neutron techniques for industrial process control

International Nuclear Information System (INIS)

Vizoso, J.R.

1980-06-01

This document describes the performance testing of an instrument for the analysis of iron laterite ore used in the production of nickel. It proved to give satisfactory results with an error less or equal to 1% under working conditions (20 0 C - 40 0 C, 80% - 85% relative humidity)

On the Origin of Bastnaesite-(La,Nd,Y in the Nissi (Patitira Bauxite Laterite Deposit, Lokris, Greece

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Sofia Kalatha

2017-03-01

Full Text Available A detailed geochemical study and a thorough mineralogical description of the rare-earth elements (REE-minerals and associated minerals were carried out in two vertical profiles of approximately 4 m length, from the Nissi (Patitira bauxite laterite deposit, Lokris, Greece, characterized by the presence of goethite in small sizes resembling bacterial cell coated by goethite and a significant REE enrichment. The enrichment of the REE concentrated in bastnaesite-group minerals, the intergrowths between REE-minerals and Al–Ni–silicates with significant sulfur contents and their association with goethite microtextures interpreted as bacteriomorphic, indicate REE remobilization along with iron bio-leaching and re-precipitation on karstified limestone. In addition to the previous-reported hydroxylbastnaesites, a (La,Nd,Y(CO3F member of the bastnaesite-group associated with Al–Ni–silicates were identified, the stability of which may reflect the dependence on the source rocks and the local variations of pH-Eh. Interaction between downward percolating water and carbonate rocks seems to be a very effective mechanism for REE fluorocarbonates deposition under alkaline and reducing conditions.

Phosphorus runoff from sewage sludge applied to different slopes of lateritic soil.

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Chen, Yan Hui; Wang, Ming Kuang; Wang, Guo; Chen, Ming Hua; Luo, Dan; Ding, Feng Hua; Li, Rong

2011-01-01

Sewage sludge (SS) applied to sloping fields at rates that exceed annual forest nutrient requirements can be a source of phosphorus (P) in runoff. This study investigates the effects of different slopes (18, 27, 36, and 45%) on P in runoff from plots amended with SS (120 Mg ha). Lateritic soil (pH 5.2) was exposed to five simulated rainfalls (90 mm h) on outdoor plots. When sludge was broadcast and mixed with surface soils, the concentrations and loss in runoff of total P in the mixed sample (MTP), total P in the settled sample (STP), total particulate P (TPP), total suspended P (TSP), and total dissolved P (TDP) were highest at 1 or 18 d after application. Initially, pollution risks to surface waters generally increased to different degrees with steeper slopes, and then diminished gradually with dwindling differences between the slopes. The runoff losses coefficient of MTP increased in the order 36 > 45 > 27 > 18%. The initial event (1 and 18 d) accounted for 67.0 to 83.6% of total runoff P losses. Particulate fraction were dominant carriers for P losses, while with the lower slopes there was higher content of P per unit particulate fraction in runoff. Phosphorus losses were greatly affected by the interaction of sludge-soil-runoff and the modification of soil properties induced by sludge amendment. It is recommended to choose lower slopes (soils should be studied further in the field under a wider diversity of conditions. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

The distribution pattern of main and trace elements in phosphatic laterites from Pirocaua Plateau (MA)

International Nuclear Information System (INIS)

Siqueira, N.V.M. de.

1982-01-01

The phosphate-laterite of Pirocaua (state of Maranhao) was studied with basis on several lines of evidence, namely, structure of the deposit, mineral distribution, variations in chemical composition and chemistry of ground waters in the region. The distribution of elements during the formation of the deposit is interpreted and the conditioning factors analysed. Air and water samples were studied respectively by X-ray diffraction and atomic absorption spectroscopy. The results show that fluctuations of the hydrostatic level were important during the formation of the phosphate horizon. When the deposit was formed there was also a decrease of the activity of the silicic acid and a parallel increase of acidity towards the top of the cross-section studied. In these conditions, Fe sup(2+) migrated towards the top of the deposit and was precipitated as Fe sup(3+) in the oxidizing zone. Migration of phosphate was in part due to its affinities to clay minerals, in which mechanism ground water played a major role. Mass balance calculations indicate that of the parent-rock is a phyllite, it is necessary an extreme enrichment in P and Sr to give the composition of the phosphate horizon. With basis on these observations we conclude that: 1) the parent-rock must have contents of P and Sr higher than the average for phyllites; or 2) the phosphate has some other source. (author)

Role of phosphate solubilizing Burkholderia spp. for successful colonization and growth promotion of Lycopodium cernuum L. (Lycopodiaceae) in lateritic belt of Birbhum district of West Bengal, India.

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Ghosh, Ranjan; Barman, Soma; Mukherjee, Rajib; Mandal, Narayan C

2016-02-01

Profuse growth of Lycpodium cernuum L. was found in phosphate deficient red lateritic soil of West Bengal, India. Interaction of vesicular-arbuscular mycorrhiza (VAM) with Lycopodium rhizoids were described earlier but association of PGPR with their rhizoids were not studied. Three potent phosphate solubilizing bacterial strains (P4, P9 and P10) associated with L. cernuum rhizoids were isolated and identified by 16S rDNA homologies on Ez-Taxon database as Burkholderia tropica, Burkholderia unamae and Burkholderia cepacia respectively. Day wise kinetics of phosphate solubilization against Ca3(PO4)2 suggested P4 (580.56±13.38 μg ml(-1)) as maximum mineral phosphate solubilizer followed by P9 (517.12±17.15 μg ml(-1)) and P10 (485.18±14.23 μg ml(-1)) at 28 °C. Release of bound phosphates by isolated strains from ferric phosphate (FePO4), aluminum phosphate (AlPO4) and four different complex rock phosphates indicated their very good phosphate solubilizng efficacy. Nitrogen independent solubilizition also supports their nitrogen fixing capabilities. Inhibition of P solubilization by calcium salts and induction by EDTA suggested pH dependent chelation of metal cations by all of the isolates. Rhizoidal colonization potentials of Burkholderia spp. were confirmed by in planta experiment and also using scanning electron microscope (SEM). Increases of total phosphate content in Lycopodium plants upon soil treatment with these isolates were also recorded. In addition siderophore production on CAS agar medium, tryptophan dependent IAA production and antifungal activities against pathogenic fungi by rhizospheric isolates deep-rooted that they have definite role in nutrient mobilization for successful colonization of L. cernuum in nutrient deficient lateritic soil. Copyright © 2015 Elsevier GmbH. All rights reserved.

Synthesis and characterization of Co3O4 prepared from atmospheric pressure acid leach liquors of nickel laterite ores

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Meng, Long; Guo, Zhan-cheng; Qu, Jing-kui; Qi, Tao; Guo, Qiang; Hou, Gui-hua; Dong, Peng-yu; Xi, Xin-guo

2018-01-01

A chemical precipitation-thermal decomposition method was developed to synthesize Co3O4 nanoparticles using cobalt liquor obtained from the atmospheric pressure acid leaching process of nickel laterite ores. The effects of the precursor reaction temperature, the concentration of Co2+, and the calcination temperature on the specific surface area, morphology, and the electrochemical behavior of the obtained Co3O4 particles were investigated. The precursor basic cobaltous carbonate and cobaltosic oxide products were characterized and analyzed by Fourier transform infrared spectroscopy, thermogravimetric differential thermal analysis, X-ray diffraction, field-emission scanning electron microscopy, specific surface area analysis, and electrochemical analysis. The results indicate that the specific surface area of the Co3O4 particles with a diameter of 30 nm, which were obtained under the optimum conditions of a precursor reaction temperature of 30°C, 0.25 mol/L Co2+, and a calcination temperature of 350°C, was 48.89 m2/g. Electrodes fabricated using Co3O4 nanoparticles exhibited good electrochemical properties, with a specific capacitance of 216.3 F/g at a scan rate of 100 mV/s.

Fibrous Platinum-Group Minerals in “Floating Chromitites” from the Loma Larga Ni-Laterite Deposit, Dominican Republic

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Thomas Aiglsperger

2016-11-01

Full Text Available This contribution reports on the observation of enigmatic fibrous platinum-group minerals (PGM found within a chromitite body included in limonite (“floating chromitite” from Ni-laterites in the Dominican Republic. Fibrous PGM have a Ru-Os-Ir-Fe dominated composition and are characterized by fibrous textures explained by grain-forming fibers which are significantly longer (1–5 µm than they are wide (~100 nm. Back-scattered electron (BSE images suggest that these nanofibers are platinum-group elements (PGE-bearing and form <5 µm thick layers of bundles which are oriented orthogonal to grains’ surfaces. Trace amounts of Si are most likely associated with PGE-bearing nanofibers. One characteristic fibrous PGM was studied in detail: XRD analyses point to ruthenian hexaferrum. However, the unpolished fibrous PGM shows numerous complex textures on its surface which are suggestive for neoformation processes: (i features suggesting growth of PGE-bearing nanofibers; (ii occurrence of PGM nanoparticles within film material (biofilm? associated with PGE-bearing nanofibers; (iii a Si-rich and crater-like texture hosting PGM nanoparticles and an Ir-rich accumulation of irregular shape; (iv complex PGM nanoparticles with ragged morphologies, resembling sponge spicules and (v oval forms (<1 µm in diameter with included PGM nanoparticles, similar to those observed in experiments with PGE-reducing bacteria. Fibrous PGM found in the limonite may have formed due to supergene (bio-weathering of fibrous Mg-silicates which were incorporated into desulphurized laurite during stages of serpentinization.

A socio-economic study along with impact assessment for laterite based technology demonstration for arsenic mitigation.

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Mondal, Sourav; Roy, Anirban; Mukherjee, Raka; Mondal, Mrinmoy; Karmakar, Sankha; Chatterjee, Somak; Mukherjee, Munmun; Bhattacharjee, Saikat; De, Sirshendu

2017-04-01

Arsenic contamination mitigation technologies have been adsorption-based, but the most widely-used and traditionally available adsorbents suffered inherent limitations, including cost infeasibility and problems associated with regeneration and disposal of the spent adsorbent. The present technology is based on indigenously developed activated laterite prepared from the naturally and abundantly available material, and can hence easily be scaled up for community usage and large scale implementation. The total arsenic removal capacity is 32.5mg/g, which is the highest among all naturally occurring arsenic adsorbents. A major issue in earlier adsorbents was that during regeneration, the adsorbed arsenic would be released back into the environment (leaching), and would eventually contaminate the groundwater again. But the adsorbent in this filter does not require regeneration during its five-year lifespan and does not leach upon disposal. An attempt is made to test and demonstrate the practical implementation of the technology - its effectiveness and viability in three community (primary schools - one in Malda and two in north 24 Parganas, West Bengal, India) and 20 household filters, catering to over 5000 people in different areas of West Bengal exposed to high arsenic contamination of groundwater (ranging from 0.05 to 0.5mg/l). The work also focuses on the social impact of the real life technological solution on the lives on the affected people in the worst hit arsenic affected communities, perhaps the greatest public health risk emergency of the decade. Copyright © 2017 Elsevier B.V. All rights reserved.

High calcium fly ash geopolymer stabilized lateritic soil and granulated blast furnace slag blends as a pavement base material.

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Phummiphan, Itthikorn; Horpibulsuk, Suksun; Rachan, Runglawan; Arulrajah, Arul; Shen, Shui-Long; Chindaprasirt, Prinya

2018-01-05

Granulated Blast Furnace Slag (GBFS) was used as a replacement material in marginal lateritic soil (LS) while class C Fly Ash (FA) was used as a precursor for the geopolymerization process to develop a low-carbon pavement base material at ambient temperature. Unconfined Compression Strength (UCS) tests were performed to investigate the strength development of geopolymer stabilized LS/GBFS blends. Scanning Electron Microscopy and X-ray Diffraction analysis were undertaken to examine the role of the various influencing factors on UCS development. The influencing factors studied included GBFS content, Na 2 SiO 3 :NaOH ratio (NS:NH) and curing time. The 7-day soaked UCS of FA geopolymer stabilized LS/GBFS blends at various NS:NH ratios tested was found to satisfy the specifications of the Thailand national road authorities. The GBFS replacement was found to be insignificant for the improvement of the UCS of FA geopolymer stabilized LS/GBFS blends at low NS:NH ratio of 50:50. Microstructural analysis indicated the coexistence of Calcium Silicate Hydrate (CSH) and Sodium Alumino Silicate Hydrate products in FA geopolymer stabilized LS/GBFS blends. This research enables GBFS, which is traditionally considered as a waste material, to be used as a replacement and partially reactive material in FA geopolymer pavement applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Unraveling climatic changes from intra-profile variation in oxygen and hydrogen isotopic composition of goethite and kaolinite in laterites: An integrated study from Yaou, French Guiana

Science.gov (United States)

Girard, Jean-Pierre; Freyssinet, Philippe; Chazot, Gilles

2000-02-01

An integrated study of O and H isotopes in the lateritic profile of Yaou, French Guiana, was undertaken to investigate the usefulness of stable isotopes as tracers of climatic changes in continental environments. The studied profile is composed of a 27 m thick saprolite, mostly developed in the past under wet-and-dry tropical climate in association with a duricrust, overlain by a 3 m thick yellow latosol formed more recently under present equatorial hot and humid climate. δ 18O-δD values determined for weathering goethite (pseudomorphs after pyrite) and kaolinite (microcrystalline clay groundmass) throughout the 30 m deep profile reflect formation temperatures consistent with present (25°C) and realistic past climatic temperatures (20°C-30°C), indicating that weathering minerals formed in isotopic equilibrium with their genetic environment and were not subjected to significant isotope exchange after formation. A distinct shift downward (2‰ for δ 18O, 15‰ for δD) from low to high δ 18O-δD values occurs around 20 m depth in the saprolite. It is interpreted as recording the change from the past tropical to the present equatorial climate. Goethite and kaolinite in the 5-10 m thick saprolite interval immediately above the active basement weathering front are in isotopic equilibrium with modern water and must have formed under present equatorial-humid conditions. In contrast, goethite and kaolinite found higher up in the saprolite and in the duricrust formed in the past under tropical wet and dry climate from waters distinctly depleted in 18O and D relative to modern water. The marked depletion of paleo-meteoric water at Yaou most likely reflects a more contrasted or "monsoonal" character of the ancient tropical climate. The present study shows that ancient weathering minerals in lateritic profiles preserve their δ 18O-δD values and carry a time signal. The time signal is best expressed in minerals formed rapidly at the weathering front and not subjected

Mechanical Properties of Millet Husk Ash Bitumen Stabilized Soil Block

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M. T. Abdulwahab

2017-06-01

Full Text Available This study presents an investigation into the improvement of strength and durability properties of lateritic soil blocks using Millet Husk Ash (MHA and Bitumen as additives so as to reduce its high cost and find alternative disposal method for agricultural waste. The lateritic soil samples were selected and treated with 0%, 10%, 15%, 20%, 30%, 40% and 50% of MHA by weight of laterite. The lateritic soil-MHA mixture was later admixed with 0%, 2%, 4%, 6%, 8%, 10%, 12% and 14% cut-back bitumen solution by weight of laterite. Both the natural lateritic soil, lateritic and MHA, and the blend of Soil, MHA and Bitumen were first subjected to physical and chemical analysis using X-Ray Fluorescence (XRF and Scanning Electromagnetic Machine (SEM to determine their engineering properties followed by the performance test on bricks cast with varying quantities of the additives. A total of one hundred and ninety two (192 cubes were tested for moisture absorption, erodability and compressive strength tests. The result of the test showed that MHA and Bitumen acted as pozzolana in performance test on the soil blocks. Up to 30% MHA – laterite and 20% MHA admixed with 8% laterite were found to give optimum compressive strength of 10.8N/mm2 and 10.9N/mm2 for the bricks produced. The result also showed that about 50% MHA blended with 14% Bitumen solution ensured water tight bricks. Thus the use of MHA as partial replacement of cement will provide an economic use of by-product and consequently produce a cheaper soil block construction without comprising its strength.

Effects of wood saw dust ash admixed with treated sisal fibre on the geotechnical properties of lateritic soil

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John Engbonye SANI

2017-12-01

Full Text Available The preliminary investigation conducted on the lateritic soil collected at Shika, Zaria shows that it falls under A-7-6 (10 classification for AASHTO (1986 and CL according to unified soil classification system USCS (ASTM 1992. The soil was treated with both wood saw dust ash (WSDA and treated sisal fiber, in stepped concentration of 0,2,4,6, and 8% for WSDA and 0, 0.25, 0.5, 0.75 and 1% treated sisal fibre by dry weight of soil using Standard proctor. The Sisal Fibre was treated with Sodium Borohydride (NaBH4 (1% wt/vol for 60 minutes at room temperature to remove the cellulose content present in the Fibre. Statistical analysis was carried out on the obtained results using XLSTART 2017 software and analysis of variance with the Microsoft Excel Analysis Tool Pak Software Package. The liquid limit (LL of the soil was found to be 48% while the plastic limit(PL is 21.27%. The maximum dry density(MDDhowever, decreases generally from a value of 1.85 Mg/m3 to 1.68Mg/m3 at 0.25% sisal fiber content/0% WSDA. It has its least value of 1.57Mg/m3 at 1% sisal fiber and 8% WSDA. The OMC increased from 18 % of the natural soil to 23.7% at 0.75% sisal fiber / 6% WSDA content. There was a general increase in the value of UCS of the soil-sisal fibre mixture with WSDA content from 100 kN/m2 of the natural soil to 696 kN/m2 at 0.75 % sisal fibre content / 6% WSDA. The UCS value met the standard of 687-1373 kN/m2 requirements of sub base for adequate lime and cement stabilization, respectively (Ingas and Metcalf 1972.

REE Comparison Between Muncung Granite Samples and their Weathering Products, Lingga Regency, Riau Islands

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Ronaldo Irzon

2016-11-01

Full Text Available DOI:10.17014/ijog.3.3.149-161The increasing demand for Rare Earth Elements (REE is related to the continous development of technology, and these elements are used in modern equipments. REE can occur in igneous and sedimentary rocks in significant amounts as primary deposits, whereas the secondary REE deposit can be produced by intensive lateritic weathering of bedrocks under the tropical or subtropical climate. Lateritic process can increase REE concentration from sub-economic levels in host rocks to be more valuable. Muncung Granite is located in a tropical area of Lingga Regency, Riau Islands Province. REE occurs in the Muncung Granite and in weathered layers (saprolite, laterite, and soil. ICP-MS was applied to measure the REE content in all samples of this study. The average REE content of the Muncung Granite is 265 ppm with Eu anomaly in REE’s spider diagrams. Lateritization process has increased REE content by more than four times compared to that in the Muncung Granite. Ce and Eu anomalies in weathered layers can be associated with weathering process and initial REE contents in the host rock. Ce anomaly in a laterite layer is found to have a negative correlation to REE total enrichment. The REE level in the Muncung Granite is higher than the content in the soil and saprolite layers, but lower than that in the laterite.

The Effect of Sample Preparation and Testing Procedure

African Journals Online (AJOL)

School of Civil & Environmental Engineering, Addis Ababa Institute of Technology,. 3. Murray Rix ... the application of laboratory testing and ... clay, tropical red clay, lateritic clay and laterite, ..... grading curves using mass and modified mass.

characterization of soil and sediments parameters of oguta – izombe

African Journals Online (AJOL)

Prof

where the clayey lateritic soil with iron oxide cementation of soil particles provides an appreciable degree of ... need for groundwater protection against pollution. Geological ..... consists of clayey laterite with iron oxide coating and cementation ...

All rights reserved Evaluation of the Layering of Rock Strata and ...

African Journals Online (AJOL)

PROF HORSFALL

correlates with the observed dry and consolidated lateritic clay ... of consolidated laterite, gravel, sand, silt and clay having a high ... from the original hydrogeologic assessment report of ... the AGRL, provision of financial and material support.

[Effects of slopes on nitrogen transport along with runoff from sloping plots on a lateritic red soil amended with sewage sludge].

Science.gov (United States)

Chen, Yan-Hui; Chen, Ming-Hua; Wang, Guo; Chen, Wen-Xiang; Yang, Shun-Cheng; Chai, Peng

2010-10-01

The effects of different slopes on nitrogen transport along with runoff from sloping plots amended with sewage sludge on a lateritic red soil were studied under simulated rainfall conditions. When the sludge was broadcasted and mixed with surface soils (BM), the MTN (total nitrogen of mixing sample), STN (total nitrogen of settled sample), TPN (total particulate nitrogen), TSN (total suspended nitrogen), TDN (total dissolved nitrogen) and NH4(+) -N concentrations and nitrogen loss amounts in runoff of all treatments were highest at 1 day or 18 days after application. The highest concentrations and the loss amounts of MTN and STN in the slope runoff for the BM treatment increased with slope degree, showing increasing pollution risks to the surface waters. The STN concentration and loss amounts from the 25 degrees plots were 126.1 mg x L(-1) and 1788.6 mg x m(-2), respectively, being 4.6 times and 5.8 times of the corresponding values from the 10 degrees plots, respectively. Then the concentrations and the loss amounts of nitrogen (except NO3(-) -N) from the BM plots diminished rapidly first and then tended to be stable with dwindling differences between the slopes. The loss of MTN and STN in early runoff (1 day and 18 days) accounted for 68.6% -73.4% and 62.3% -66.7% of the cumulative loss amounts during the experimental period for all the broadcasted treatments. Runoff loss coefficients of MTN increased in the order of 20 degrees > 25 degrees > 15 degrees > 10 degrees. Nitrogen was largely lost in dissolved species while large portion of NH4(+) -N was lost with particulates.

Author Details

African Journals Online (AJOL)

Abstract PDF · Vol 28, No 2 (2009) - Research papers. Effects of Compaction Delay on the Properties of Cement-Bound Lateritic Soils Abstract PDF · Vol 35, No 3 (2016) - Building, Civil & Geotechical Engineering CLASSICAL OPTIMIZATION OF BAGASSE ASH CONTENT IN CEMENT-STABILIZED LATERITIC SOIL

Absorption of gamma-emitting fission products and activation products by rice under flooded and unflooded conditions from two tropical soils

International Nuclear Information System (INIS)

D'Souza, T.J.; Mistry, K.B.

1980-01-01

The absorption of gamma-emitting fission products 106 Ru, 125 Sb, 137 Cs and 144 Ce and activation products 59 Fe, 58 Co, 54 Mn and 65 Zn by rice plants grown on two contrasting tropical soils, namely, a blak soil (pellustert) and a laterite (oxisol), and the effects of flooding were studied under controlled conditions. Results indicated greater uptake of 106 Ru and 125 Sb from the black soil than from the laterite. In contrast, the uptake of 144 Ce and 137 Cs was greater in the laterite than in the black soil. Flooding treatment enhanced the uptake of all these fission products by rice plants in the laterite soil whereas this effect was observed only for 125 Sb and 137 Cs in the black soil. The plant uptake of activation products from the two soil types showed maximum accumulation of 65 Zn followed by 54 Mn, 59 Fe and 58 Co in both soil types. Besides, uptake of these nuclides was greater from the laterite soil than from the black soil. Flooding treatment for rice while showing a reduction of 59 Fe uptake showed an increase in plant uptake of 58 Co, 54 Mn and 65 Zn in both soil types. (orig.)

Growing Periandra mediterranea on post-mining substrate: native Fabaceae with potential for revegetation of degraded rupestrian grasslands in Brazil

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Maurilio Assis Figueiredo

2018-01-01

Full Text Available ABSTRACT Recovery of degraded areas of rupestrian grasslands is hampered mainly by the limited knowledge regarding substrate management and the biology of native species suitable for revegetation of these areas. The aim of our study was to examine the establishment and growth of Periandra mediterranea in different textures of lateritic substrate from a mining-degraded area. The growth of P. mediterranea was evaluated using fine and coarse laterite, both with and without the addition of topsoil. Survival, dry biomass, content of chemical elements and nodulation were evaluated in ten individuals per treatment sixteen months after planting. Although the substrate has low nutrient content, yet high metal concentrations, all plants survived. Plants growing on coarse laterite had 140 % greater biomass than those growing on fine laterite. The addition of topsoil increased biomass in coarse and fine laterite by 46 and 151 %, respectively, and doubled the number of nodulated plants, regardless of grain size. The biomass accumulation of P. mediterranea to a dystrophic substrate revealed its potential for use in the revegetation of degraded areas of rupestrian grasslands. Furthermore, the addition of topsoil facilitated the association of P. mediterranea with nitrogen-fixing bacteria, and increased its growth and capacity to improve substrate fertility.

Author Details

African Journals Online (AJOL)

Geotechnical properties of lateritic soil developed over quartz schist in Ishara area, south western Nigeria Details · Vol 44, No 1 (2008) - Articles Comparative study of the influence of cement and lime stabilization on geotechnical properties of lateritic soil derived from pegmatite in Ago-Iwoye area, southwestern Nigeria

De invloed van den kalktoestand van juvenielen Merapi-aschgrond op eenige kwaliteitseigenschappen van Vorstenlandsche tabak

NARCIS (Netherlands)

Middelburg, H.A.

1932-01-01

The influence of lime status of volcanic-ash soil was examined by pot trials in conditions as similar as possible to those of the plantation. Soils used were fine juvenile Merapi ash, the most important soil for tobacco growing, and, as a contrast, weathered laterite. In laterite artificial

Nd and Sr isotopes: implications of provenance and geological mapping; Isotopos de Nd e Sr: implicacoes de proveniencia e mapeamento geologico

Energy Technology Data Exchange (ETDEWEB)

Albuquerque, Marcio Fernando dos Santos; Horbe, Adriana Maria Coimbra; Dantas, Elton Luiz, E-mail: mgeoroots@gmail.com, E-mail: ahorbe@unb.br, E-mail: elton@unb.br [Universidade de Brasilia (UnB), DF (Brazil). Instituto de Geociencias

2015-07-01

XRD, Nd and Sr isotopes, major, minor and traces elements quantification were applied to rocks, lateritic crusts and soils from Sumauma Supergroup and Alto Tapajos Group, in order to indicate provenance of the rocks and using lateritic products as geologic mapping tool. For the rocks, the results showed sources related to provinces Tapajos Parima, Rondonia Juruena, Sunsas, Carajas and Amazonia Central. However, the incision of Cachimbo graben allowed which the Sumauma Supergroup erosion also were source for the Alto Tapajos Group, allied to contribution of volcanics from Colider Group. Lateritic crusts and soils are correlates to bedrocks, allowing the use as geologic mapping tool. (author)

Nd and Sr isotopes: implications of provenance and geological mapping

International Nuclear Information System (INIS)

Albuquerque, Marcio Fernando dos Santos; Horbe, Adriana Maria Coimbra; Dantas, Elton Luiz

2015-01-01

XRD, Nd and Sr isotopes, major, minor and traces elements quantification were applied to rocks, lateritic crusts and soils from Sumauma Supergroup and Alto Tapajos Group, in order to indicate provenance of the rocks and using lateritic products as geologic mapping tool. For the rocks, the results showed sources related to provinces Tapajos Parima, Rondonia Juruena, Sunsas, Carajas and Amazonia Central. However, the incision of Cachimbo graben allowed which the Sumauma Supergroup erosion also were source for the Alto Tapajos Group, allied to contribution of volcanics from Colider Group. Lateritic crusts and soils are correlates to bedrocks, allowing the use as geologic mapping tool. (author)

Absorption of gamma-emitting fission products and activation products by rice under flooded and unflooded conditions from two tropical soils

Energy Technology Data Exchange (ETDEWEB)

D' Souza, T J; Mistry, K B [Bhabha Atomic Research Centre, Bombay (India). Biology and Agriculture Div.

1980-01-01

The absorption of gamma-emitting fission products /sup 106/Ru, /sup 125/Sb, /sup 137/Cs and /sup 144/Ce and activation products /sup 59/Fe, /sup 58/Co, /sup 54/Mn and /sup 65/Zn by rice plants grown on two contrasting tropical soils, namely, a blak soil (pellustert) and a laterite (oxisol), and the effects of flooding were studied under controlled conditions. Results indicated greater uptake of /sup 106/Ru and /sup 125/Sb from the black soil than from the laterite. In contrast, the uptake of /sup 144/Ce and /sup 137/Cs was greater in the laterite than in the black soil. Flooding treatment enhanced the uptake of all these fission products by rice plants in the laterite soil whereas this effect was observed only for /sup 125/Sb and /sup 137/Cs in the black soil. The plant uptake of activation products from the two soil types showed maximum accumulation of /sup 65/Zn followed by /sup 54/Mn, /sup 59/Fe and /sup 58/Co in both soil types. Besides, uptake of these nuclides was greater from the laterite soil than from the black soil. Flooding treatment for rice while showing a reduction of /sup 59/Fe uptake showed an increase in plant uptake of /sup 58/Co, /sup 54/Mn and /sup 65/Zn in both soil types.

Mechanical properties of millet husk ash bitumen stabilized soil block

African Journals Online (AJOL)

This study presents an investigation into the improvement of strength and durability properties of lateritic soil blocks using Millet Husk Ash (MHA) and Bitumen as additives so as to reduce its high cost and find alternative disposal method for agricultural waste. The lateritic soil samples were selected and treated with 0%, ...

Efficiency of Syrian and Indian rock phosphates for maize in two soils amended with sulphur

International Nuclear Information System (INIS)

Kanacri, S.

1995-01-01

A greenhouse pot experiment was conducted to evaluate the fertilizer use efficiency of three Syrian rock phosphates in comparison to Mussoorie rock phosphate from India for maize grown in a laterite (ultisol) and an alluvial (entisol) soil amended with sulphur, and using sup 3 sup 2 P-labelled triple superphosphate (TSP). Results showed that application of rock phosphates (RPs) to laterite soil significantly increased the dry matter yields of maize shoots, whereas, in alluvial soil, RPs were not found effective in increasing the yields. Data further indicated that all the three Syrian RPs were equally efficient in increasing dry matter yields in laterite soil and were superior to Mussoorie rock phosphate (MRP). Sulphur added in combination with RPs significantly enhanced the dry matter production as well as 'A' value of alluvial soil. Application of sulphur in conjunction with RPs significantly increased the 'A' value of laterite soil however, sulphur did not contribute to any significant increase in the yields. Syrian RPs were more reactive in soils than Mussoorie RP. (author). 7 refs., 6 tabs

Efficiency of Syrian and Indian rock phosphates for maize in two soils amended with sulphur

International Nuclear Information System (INIS)

Kanacri, Saloi; Bhujbal, B.M.

1993-01-01

A greenhouse pot experiment was conducted to evaluate the fertilizer use efficiency of three Syrian rock phosphates in comparison to Mussoorie rock phosphate from India for maize grown in a laterite (ultisol) and an alluvial (entisol) soil amended with sulphur, and using 32 P-labelled triple superphosphate (TSP). Results showed that application of rock phosphates (RPs) to laterite soil significantly increased the dry matter yields of maize shoots, whereas, in alluvial soil, RPs were not found effective in increasing the yields. Data further indicated that all the three Syrian RPs were equally efficient in increasing dry matter yields in laterite soil and were superior to Mussoorie rock phosphate (MRP). Sulphur added in combination with RPs significantly enhanced the dry matter production as well as 'A'value of alluvial soil. Application of sulphur in conjunction with RPs significantly increased the 'A' value of laterite soil, however, sulphur did not contribute to any significant increase in the yields. Syrian RPs were more reactive in soils than Mussoorie RP. (author). 7 refs., 6 tabs

Summary of a Situation from Laboratory Investigation of Yugoslav Nickel Bearing Ores by Segregation-Flotation-Magnetic Separation

OpenAIRE

Krstev, Boris; Ilic, Ilija

1988-01-01

A huge list of current laterite operations or laterites processing is following: Fe - ni smelting, Matte smelting, Reduction roasting-ammonia leaching and HPA leaching. Apart from the above mentioned process routes, there have been many attempts to develop processes know as alternative processes, which have included: Sulphuric, Nitric acid leaching, Chlorine leaching, Acid pugging and sulphating roast, especially Segregation Process etc.

Temperature effect on water absorption in an improved periwinkle ...

African Journals Online (AJOL)

Studies have been carried out on the water absorption of the improved periwinkle reinforced cement stabilized lateritic bricks. These bricks were produced at different cement to laterite to periwinkle ratio of 1:3:1, 2:3:1, 3:3:1, 3:2:1, 3:1:1, and fired at an elevated temperature of 10000C and 11500C, respectively. From the ...

Requerimientos tecnológicos del transportador de laterita hacia el molino de bolas, de la Empresa Productora de Níquel Comandante Ernesto Guevara; Technological Requirements of the Conveyor Belt which Carries Laterite to the Balls Mill in Nickel Producer

Directory of Open Access Journals (Sweden)

Javier Muñoz Álvarez

2011-02-01

Full Text Available Se describe el flujo productivo existente en la Empresa Productora del Níquel Comandante Ernesto Guevara,hasta la etapa de la molienda seca, con énfasis en los detalles técnicos de mayor relevancia en el proceso.Se analiza la influencia de la cantidad de mineral en el sistema sobre el comportamiento energético de lamolienda. Finalmente se determinan los requerimientos tecnológicos impuestos por el transportador delaterita 215 - TR - 201 al accionamiento eléctrico, en función de las características y las necesidades delproceso. In the paper, the productive flow existing in the nickel producer enterprise Commandant Ernesto Guevarawas described until the stage of dry milling, with an emphasis on the technical details of greater relevancy inthe process. There was analyzed the influence of the amount of mineral in the system over the energyconsumption performance of the milling. Finally it were identified the technological requirements imposed bythe 215 - TR - 201 laterite carrier to the electric drive, according to the characteristics and needs of theprocess.

Speciation of rare earth elements in different types of soils in China

International Nuclear Information System (INIS)

Wang Lijun; Zhang Shen; Gao Xiaojiang; Liu Shujuan

1997-01-01

Contents, distribution patterns, physical and chemical speciation of rare earth elements (REEs) in laterite (tropical zone), red earth (middle subtripical earth), yellow brown soil (Northern subtripical earth), cinnamon soil (warm temperature zone), leached chernozem (temperate zone) and albic bleached soil (temperate zone) in China were determined with instrumental neutron activation analysis (INAA). Content and distribution patterns of ERRs are closely related to soil mechanical composition. In laterite, red earth, yellow brown soil and leached chernozem, REEs mainly enrich in fine grain particles or coarser grain partials while in clay particles no such enrichment was found. The distribution patterns of REEs in these soils are consistent with the REE features of their parent rocks. In all the six soils, REEs mainly exist in residual form, and with the increase of atomic number, intermediate REEs (IRRE) have lower proportions of residual form than light REEs (LREE) and heavy REEs (HREE). For the six unstable forms, water soluble form has the lowest proportion. The proportions of exchangeable form, carbonate and specific adsorption form are lower. The proportions of Fe-Min oxides form in different types of soils decrease gradually from Southern China to Northern China following the order: laterite > red earth > yellow brown soil > cinnamon soil, leached chernozem, albic bleached soil. Proportions of bound organic matters are higher and follow the order: Albic bleached soil > leached chernozem > red earth > laterite > yellow brown soil > cinnamon soil. The albic bleached soil has higher proportion of softly bound organic matter form. The leached chernozem has higher proportion of tightly bound organic matter form. Form of bound to organic matter in laterite is almost totally made up of form of softly bound to organic matter

Distribution of rare-earths in solid solution crandalita- goyazita of Sapucaia (Bonito-Para)

International Nuclear Information System (INIS)

Costa, M.L. da; Melo Costa, W.A. de

1987-01-01

The Crandallite are predominant in the lateritic phosphates of Sapucaia, in the form of the solid solution Crandallite (Cn)- Goyazite (Gz)-Florencite (Fl). The Crandallite-Goyazite is predominant, where the maximum proportion of Florencite is Cn 60 Cz 34.8 Fl 5.2 - This proportion of Florencite is relatively high for laterites, and for this case having up to 1,374% weight of TR 2 O 3 in the total sample. The light rare elements are predominant over the heavy ores, and are illustrated in the distribution curve normalized for the chondrites. This curve is partially comparable with the curve for Apatite presents slight negative anomaly for the element Europium, and slight positive anomaly for The elements Thulium. The geochemical caracteristics for the rare earths in this group allow the prediction for the original rock for the laterites. (author) [pt

Comportement des sols latéritiques compactés dans les remblais et digues de retenue des rejets miniers du Katanga (RDC)

OpenAIRE

Mukoko Kalenda, Gustave

2014-01-01

The use of laterites as building materials in the tropical countries, in particular in the road embankments and restraint dikes of mining discharge is strongly increased. After their implementation in tailings sites to dyke the mining discharges to avoid diffuse pollution in the environment, these lateritic materials are submitted to complex solicitation which can influence in a very important way their hydromechanical properties. In most of the cases of breaks of dikes, hydraulic fracturing ...

Exploration for uranium in a tropical country: a case history in the Central African Republic

International Nuclear Information System (INIS)

Molina, P.

1983-01-01

A total-count aerial radiometric survey carried out in the Central African Republic, in a wet tropical environment, led to the discovery of several anomalies, which were found to be bound to laterites overlying in Archean, quarzite-micaschist metamorphic series. Ground verification included several techniques: regional photogeology, radiometry and stream sediment geochemistry. Each anomalous spot was studied in detail by radiometric and geochemical grids, local topographic study and trenching through the lateritic profile. (author)

Preliminary Study of Compositional Analysis in Stone Sanctuaries by Nuclear Method

International Nuclear Information System (INIS)

Fungklin, Ratchai; Wonglee, Poonsuk; Khaweerat, Sasiphan; Pimjun, Surapong; Chongkum, Somporn

2003-10-01

Ten Sandstone and laterite samples were collected from stone sanctuaries at the northeast of Thailand. Neutron activation analysis (NAA) using Thai-Research Reactor (TRR-1/M1) at Office of Atoms for Peace was employed to investigate the samples. The result shows that elemental composition in samples can be used to classify the type of sandstone and laterite from their different formations. Moreover the elemental composition in the older stone monastery has lower level than the younger one

Compressive Strength of Volcanic Ash/Ordinary Portland Cement Laterized Concrete

Directory of Open Access Journals (Sweden)

Olusola K. O.

2010-01-01

Full Text Available This study investigates the effect of partial replacement of cement with volcanic ash (VA on the compressive strength of laterized concrete. A total of 192 cubes of 150mm dimensions were cast and cured in water for 7, 14, 21, and 28 days of hydration with cement replacement by VA and sand replacement by laterite both ranging from 0 to 30% respectively, while a control mix of 28-day target strength of 25 N/mm2 was adopted. The results show that the density and compressive strength of concrete decreased with increase in volcanic ash content. The 28-day, density dropped from 2390 kg/m3 to 2285 kg/m3 (i.e. 4.4% loss and the compressive strength from 25.08 N/mm2 to 17.98 N/mm2 (i.e. 28% loss for 0-30% variation of VA content with no laterite introduced. The compressive strength also decreased with increase in laterite content; the strength of the laterized concrete however increases as the curing age progresses.

Combinatorial Optimization for Energy Saving in Nickel Industry Non-Newtonian Fluid Pumping System

International Nuclear Information System (INIS)

Hernández Ramírez, Gabriel; Legra Lobaina, Aristides; Columbié Navarro, Angel; Marcos Aníbal León Segovia

2017-01-01

In the present work a study of the influence of the rheological parameters of the lateritic hydromixtures with the energetic ones of the pumping systems that guarantee the productivity of nickel company 'Commander Pedro Sotto Alba' is carried out. From an experimental study and through an estimator, the rheological parameters are modeled as a function of the factors: temperature, solids content, chemical and granulometric composition. From an appropriate discretization of the model of the lateritic hydrometer pumping system and the application of a Discrete Combination Optimization Double Sequencing procedure, the operating parameters of this system were obtained, in order to guarantee a flow rate of 1600 m3 / h and one Adequate solids concentration. It is concluded that the use of a mathematical model that relates the rheological parameters of the lateritic pulp and the energy parameters of the pumping system, guarantee the metallurgical and energy efficiency in the acid leaching process with an average increase in production between 1000-1500 T Ni + Co / y and an energy saving of 30 MWh /year. (author)

Determination of Barium and selected rare-earth elements in geological materials employing a HpGe detector by radioisotope excited x-ray fluorescence

International Nuclear Information System (INIS)

LaBrecque, J.J.; Preiss, I.L.

1984-01-01

The laterite material (geological) from Cerro Impacto was first studied by air radiometric techniques in the 1970's and was found to have an abnormally high radioactive background. Further studies showed this deposit to be rich in thorium, columbium, barium and rare-earth elements (mostly La, Ce, Pr and Nd). A similar work has been reported for the analysis of Brazil's lateritic material from Morro do Ferro to determine elemental compositions (including barium and rare-earth elements) and its relationship to the mobilization of thorium from the deposit using a Co-57 radioisotope source. The objective of this work was to develop an analytical method to determine barium and rare-earth element present in Venezuelan lateritic material from Cerro Impacto. We have employed a method before, employing a Si(Li) detector, but due to the low detection efficiencies in the rare-earth K-lines region (about 30 KeV - 40 KeV), we have decided to study the improvement in sensitivities and detection limits using an hyperpure germanium detector

Nitrogen fixation by free-living organisms in rice soils. Studies with 15N

International Nuclear Information System (INIS)

Rao, V.R.; Charyulu, P.B.B.N.; Nayak, D.N.; Ramakrishna, C.

1979-01-01

Heterotrophic nitrogen fixation as influenced by water regime, organic matter, combined nitrogen and pesticides was investigated in several Indian rice soils by means of the 15 N 2 tracer technique. Soil submergence accelerated nitrogen fixation. Addition of cellulose to both non-flooded and flooded soils enhanced nitrogen fixation. Under submerged conditions, addition of sucrose, glucose and malate in that order stimulated nitrogen fixation in alluvial soil, while only sucrose enhanced nitrogen fixation in laterite soil. Nitrogen fixation in flooded alluvial and laterite soils decreased with increasing concentration of combined nitrogen. Nitrogen fixation was appreciable in acid sulphate and saline soils under both flooded and non-flooded conditions, despite high salinity and acidity. Application of certain pesticides at rates equivalent to recommended field level greatly influenced nitrogen fixation in flooded rice soils. Additions of benomyl (carbamate fungicide) and carbofuran (methyl carbamate insecticide) to alluvial and laterite soils resulted in significant stimulation of nitrogen fixation. Gamma-BHC stimulated nitrogen fixation only in alluvial soil, with considerable inhibition in a laterite soil. Nitrogen fixation by Azospirillum lipoferum was investigated by 15 N 2 . Large variations in 15 N 2 incorporation by A. lipoferum isolated from the roots of several rice cultivars was observed. Specific lines of rice harbouring A. lipoferum with high nitrogenase activity might be selected. Nitrogen fixed by heterotrophic organisms in a complex system such as soil could not be evaluated precisely. Indigenous nitrogen fixation in a flooded soil would be in the range of 5-10 kg N/ha, increasable 3 to 4-fold by appropriate fertilizers and cultural practices

Unraveling climatic changes from intraprofile variation in oxygen and hydrogen isotopic composition of goethite and kaolinite in laterites: An integrated study from Yaou, French Guiana

Energy Technology Data Exchange (ETDEWEB)

Girard, J.P.; Freyssinet, P.; Chazot, G.

2000-02-01

An integrated study of O and H isotopes in the latertic profile of Yaou, French Guiana, was undertaken to investigate the usefulness of stable isotopes as tracers of climatic changes in continental environments. The studied profile is composed of a 27 m thick saprolite, mostly developed in the past under wet-and-dry tropical climate in association with a duricrust, overlain by a 3 m thick yellow latosol formed more recently under present equatorial hot and humid climate. {delta}{sup 18}O-{delta}D values determined for weathering goethite (pseudomorphs after pyrite) and kaolinite (microcrystalline clay groundmass) throughout the 30 m deep profile reflect formation temperatures consistent with present (25 C) and realistic past climatic temperatures (20 C--30 C), indicating that weathering minerals formed in isotopic equilibrium with their genetic environment and were not subjected to significant isotope exchange after formation. A distinct shift downward from low to high {delta}{sup 18}O-{delta}D values occurs around 20 m depth in the saprolite. It is interpreted as recording the change from the past tropical to the present equatorial climate. Goethite and kaolinite in the 5--10 m thick saprolite interval immediately above the active basement weathering front are in isotopic equilibrium with modern water and must have formed under present equatorial-humid conditions. In contrast, goethite and kaolinite found higher up on the saprolite and in the duricrust formed in the past under tropical wet and dry climate from waters distinctly depleted in {sup 18}O and D relative to modern water. The marked depletion of paleo-meteoric water at Yaou most likely reflects a more contrasted or monsoonal character of the ancient tropical climate. The present study shows that ancient weathering minerals in lateritic profiles preserve their {delta}{sup 18}O-{delta}D values and carry a time signal. The time signal is best expressed in minerals formed rapidly at the weathering front and

Geochemical and mineralogical constraints on the distribution and enrichment of the rare earth elements during pedogenesis and tropical weathering

Science.gov (United States)

Hardy, Liam; Smith, Martin; Moles, Norman; Marsellos, Antonios

2015-04-01

Current European manufacturing relies heavily on imports from the USA & China for unprocessed rare earth elements (REEs) and rare earth oxides (REOs). It has been suggested that the EU holds viable reserves of REEs that, with adequate research, could satisfy 10% of EU industrial demand, by the recycling of mine waste from bauxite production (red muds) alone (Deady, E. (BGS), 2014). Focus has been turned to the potential for Mount Weld type laterite deposits being exploited in the EU, but limited exploration and understanding of EU laterite (& paleo laterite) formations currently makes them unattractive to investment. Although previously researched, the full range of factors influencing the transition of rare earth (primarily lanthanide series, Y & Sc) elements between mineral and clay phases in allochthonous soils, saprolites and laterites is not fully understood, especially in present and Paleo-European environments (Herrington, Boni, Skarpelis, & Large, 2007) (Deady, E. (BGS), 2014) but several deposits globally are suggested to have formed at economically viable concentrations due to this secondary remobilisation & transition from mineral to clay phase and subsequent seasonal leaching and evaporation system, to form depositional buffer zones other than the soil base. (Hoatson, Jaireth, & Miezitis, 2011) (Berger, Janots, Gnos, Frei, & Bernier, 2014). This project intends to use new techniques in sequential extractions, ICP-MS, Quantitative XRD & SEM analysis to expand current knowledge around lateritic & allochtonous ore forming, & weathering processes. Heavy REE content and mineralogical variations in clays will be examined, with examples from a selection of profiles across Southern Europe (and potentially paleo soils from Scandinavia) to define the main influencing factors on REE concentration. Are the specific sites enriched simply by the nature of their source rock (protolith), by the soil formation (pedogenesis), or by biogenic & meteorological factors

Efficiency of ammonium nitrate phosphates of varying water-soluble phosphorus content for rice and succeeding maize crop on contrasting soil types. [/sup 32/P-labelled fertilizers

Energy Technology Data Exchange (ETDEWEB)

Bhujbal, B M; Mistry, K B [Bhabha Atomic Research Centre, Bombay (India). Biology and Agriculture Div.; Chapke, V G; Mutatkar, V K [Fertilizer Corp. of India Ltd., Bombay

1977-09-01

Efficiency of ammonium nitrate phosphates (ANP) containing 30 and 50 percent of water-soluble phosphorus (W.S.P.) vis-a-vis that of entirely water-soluble monoammonium orthophosphate (MAP) for rice and succeeding maize crop on phosphate responsive laterite, red sandy loam (Chalka) and calcareous black soils was examined in greenhouse experiments. Data on dry matter yield, uptake of phosphorus, utilization of applied fertilizer, 'Effective Rate of Application' and 'Relative Efficiency percent' at flowering stage of rice indicated no significant differences between ammonium nitrate phosphate (30 percent and 50 percent water-soluble ohosphorus) and monoammonium orthophosphate (MAP) on laterits and natural red sandy loam soils. MAP was significantly superior to the two ANP fertilizers on calcareous black soil; no significant differences were observed between ANP (30 percent W.S.P.) and ANP (50 percent W.S.P.) on this soil. The succeeding maize crop grown up to flowering in the same pots indicated that the residual value of ANP (30 percent W.S.P.) was equal or superior to that of MAP on the laterits as well as calcareous black soil. No significant differences were detected between the residual values of the two water-solubility grades of ANP. Incubation under submerged conditions for periods upto 60 days showed that 0.5 M NaHCO/sub 3/ (pH 8.5) extractable phosphorus (plant-available phosphate) in the ANP (30 percent W.S.P.) treatment was, in general, equal to those in the MAP treatments in the laterite and red sandy loam but was significantly lower in the calcareous black soil. No marked differences were observed between the effects of the two ANP fertilizers.

Efficiency of ammonium nitrate phosphates of varying water-soluble phosphorus content for rice and succeeding maize crop on contrasting soil types

International Nuclear Information System (INIS)

Bhujbal, B.M.; Mistry, K.B.; Chapke, V.G.; Mutatkar, V.K.

1977-01-01

Efficiency of ammonium nitrate phosphates (ANP) containing 30 and 50 percent of water-soluble phosphorus (W.S.P.) vis-a-vis that of entirely water-soluble monoammonium orthophosphate (MAP) for rice and succeeding maize crop on phosphate responsive laterite, red sandy loam (Chalka) and calcareous black soils was examined in greenhouse experiments. Data on dry matter yield, uptake of phosphorus, utilization of applied fertilizer, 'Effective Rate of Application' and 'Relative Efficiency percent' at flowering stage of rice indicated no significant differences between ammonium nitrate phosphate (30 percent and 50 percent water-soluble ohosphorus) and monoammonium orthophosphate (MAP) on laterits and natural red sandy loam soils. MAP was significantly superior to the two ANP fertilizers on calcareous black soil; no significant differences were observed between ANP (30 percent W.S.P.) and ANP (50 percent W.S.P.) on this soil. The succeeding maize crop grown up to flowering in the same pots indicated that the residual value of ANP (30 percent W.S.P.) was equal or superior to that of MAP on the laterits as well as calcareous black soil. No significant differences were detected between the residual values of the two water-solubility grades of ANP. Incubation under submerged conditions for periods upto 60 days showed that 0.5 M NaHCO 3 (pH 8.5) extractable phosphorus (plant-available phosphate) in the ANP (30 percent W.S.P.) treatment was, in general, equal to those in the MAP treatments in the laterite and red sandy loam but was significantly lower in the calcareous black soil. No marked differences were observed between the effects of the two ANP fertilizers. (author)

Hydrometallurgical processing of nickel lateritic ores / Гидрометаллургическая обработка латеритных руд никеля / Hidrometalurško tretiranje lateritnih ruda nikla

Directory of Open Access Journals (Sweden)

Srećko R. Stopić

2016-10-01

Full Text Available Nickel production is a very important activity for the European Union because nickel is a unique constituent of stainless steel. Europe has lateritic (oxidic ore deposits along a very well-known belt starting from the Alps and ending to the Himalayas. The lateritic belt passes through western Balkans and Greece and continues through Turkey to Asia. The known lateritic deposits in Serbia are located in three different areas called: Zapadna Morava (Rudjinci, Veluce, Ba, Sumadija (Lipovac, Kolarevici, Bucje and Mokra Gora, which have many natural resources such as forests, rivers, etc. Therefore, it is very important to understand and show hydrometallurgical treatments of lateritic ores via mining and metallurgy in different parts of the world. In this paper, several exploitation scenarios for hydrometallurgical treatment and benefication of lateritic ores will be shown: Direct Nickel Process, Ravensthorpe and Murrin Murrin in Australia and Meta Cobalt Nickel in Turkey. / Производство никеля представляет важную отрасль промышленности в Евросоюзе, так как никель является составляющим элементом в производстве нержавеющей стали. Европа обладает ресурсами оксидных руд, находящихся на большой территории от Альп до Гималаев, охватывая западную часть Балкан и Грецию, простилаясь через Турцию до Азии. Известные резервы латеритных руд находятся в Сербии, располагаясь в трех зонах: Западная Морава (Руждинцы, Велуце, Ба, Шумадия (Липовац, Коларевичи, Бучье и Мокра Гора, представляющих собой природные ресурсы, �

Utilization of fertilizer phosphorus in rice wheat cropping sequence on different soils

International Nuclear Information System (INIS)

Singhania, R.A.; Goswami, N.N.

1975-01-01

Uptake and utilization of fertilizer phosphorus was studied in a rice-wheat cropping pattern on alluvial, black, red and laterite soils from representative model agronomic centres. Phosphorus was applied as 32 P-tagged superphosphate to rice at varying doses, depending upon the phosphorus fixing capacity of the soil, and to wheat at 30 kg P 2 O 5 /ha. Results showed that rice responded to phosphorus in all soils, but to higher doses only in black and laterite soils which had higher P-fixation capacity. Phosphorus applied to rice had little residual effect on the suceeding crop of wheat but the latter showed higher uptake and utilization of fertilizer phosphorus directly applied to it as compared to that by rice. Wheat responded to P only in red and laterite soils. Results on the transformation of applied P was converted to Fe-P which was of lower availability. These findings suggest that phosphorus in a rice-wheat sequence should preferably be applied to wheat primarily because of (1) greater uptake of fertilizer P by wheat (2) under flooded conditions in which rice is grown most of the applied P is transformed into Fe-P and (3) rice can utilize Fe-P better. (author)

Mineralogical and geochemical characterization of supergene Cu-Pb-Zn-V ores in the Oriental High Atlas, Morocco

Science.gov (United States)

Verhaert, Michèle; Bernard, Alain; Dekoninck, Augustin; Lafforgue, Ludovic; Saddiqi, Omar; Yans, Johan

2017-10-01

In the Moroccan High Atlas, two sulfide deposits hosted by Jurassic dolostones underwent significant weathering. In the Cu deposit of Jbel Klakh, several stages of supergene mineralization are distinguished: (1) the replacement of hypogene sulfides in the protolith (chalcopyrite) by secondary sulfides in the cementation zone (bornite, digenite, chalcocite, covellite), (2) the formation of oxidized minerals in the saprolite (malachite, azurite, brochantite) where the environment becomes more oxidizing and neutral, and (3) the precipitation of late carbonates (calcite) and iron (hydr-)oxides in the laterite. The precipitation of carbonates is related to the dissolution of dolomitic host rocks, which buffers the fluid acidity due to the oxidation of sulfides. In the Jbel Haouanit Pb-Zn deposit, the mineral assemblage is dominated by typical calamine minerals, Cu minerals (chalcocite, covellite, malachite), and a Cu-Pb-Zn vanadate (mottramite). Galena is successively weathered in anglesite and cerussite. Sphalerite is weathered in smithsonite, which is rapidly replaced by hydrozincite. Late iron (hydr-)oxides are mainly found at the top of both deposits (laterite). Both deposits are thus characterized by specific mineral zoning, from laterite to protolith, related to variations in the mineralogy and ore grades and probably caused by varying Eh-pH conditions.

Genèse d'un horizon tacheté par déferruginisation dans une couverture à latérite du Bassin amazonien

Science.gov (United States)

Rosolen, Vania; Lamotte, Mathieu; Boulet, René; Trichet, Jean; Rouer, Olivier; José Melfi, Adolpho

A mottled horizon in a laterite cover (without any duricrust) was studied by microscopy and quantitative chemical microanalysis. Apart from the voids, light red spots consisting of Fe-rich particles (≈2 μm) are set in clayey plasma. Dark red spots consisted of concentrations of Fe-rich particles. These patterns are inherited. On the border of structural or biological voids, where Fe-depletion features are systematic, gray or yellow spots result from dissolution of the Fe-rich particles and impregnation of the plasma by iron, respectively. The present Fe-depletion is the dominant process that explains the mottled differentiation and the absence of lateritic duricrust. To cite this article: V. Rosolen et al., C. R. Geoscience 334 (2002) 187-195.

SOUTHERN WELO, ETHIOPIA

African Journals Online (AJOL)

geomorphic processes control the formation and distribution of most soils .... minerals were determined on a graduated mechanical stage using a point counter .... clasts (fresh); Vcw, Volcanic clasts (weathered); Lat, laterite; Ox, oxides.

Laboratory investigation of TerraZyme as a soil stabilizer

Science.gov (United States)

Yusoff, Siti Aimi Nadia Mohd; Azmi, Mastura; Ramli, Harris; Bakar, Ismail; Wijeyesekera, D. C.; Zainorabidin, Adnan

2017-10-01

In this study, a laboratory investigation was conducted to examine the performance of TerraZyme on different soil types. Laterite and kaolin were treated with 2% and 5% TerraZyme to determine changes in the soils' geotechnical properties. The obtained results were analysed and investigated in terms of compaction, Unconfined Compressive Strength (UCS) and California Bearing Ratio (CBR). The changes in geotechnical properties of the stabilised and unstabilised soils were monitored after curing periods of 0, 7, 15, 21 and 30 days. Changes in compaction properties, UCS and CBR were observed. It was found that laterite with 5% TerraZyme gave a higher maximum dry density (MDD) and decreased the optimum moisture content (OMC). For kaolin, a different TerraZyme percentage did not show any effect on both MDD and OMC. For strength properties, it was found that 2% TerraZyme showed the greatest change in UCS over a 30-day curing period. The CBR value of stabilised kaolin with 2% TerraZyme gave a higher CBR value than the kaolin treated with 5% TerraZyme. It was also found that laterite treated with TerraZyme gave a higher CBR value. Lastly, it can be concluded that TerraZyme is not suitable for stabilising kaolin; TerraZyme requires a cohesive soil to achieve a better performance.

Adsorption-desorption behavior of atrazine on agricultural soils in China.

Science.gov (United States)

Yue, Lin; Ge, ChengJun; Feng, Dan; Yu, Huamei; Deng, Hui; Fu, Bomin

2017-07-01

Adsorption and desorption are important processes that affect atrazine transport, transformation, and bioavailability in soils. In this study, the adsorption-desorption characteristics of atrazine in three soils (laterite, paddy soil and alluvial soil) were evaluated using the batch equilibrium method. The results showed that the kinetics of atrazine in soils was completed in two steps: a "fast" adsorption and a "slow" adsorption and could be well described by pseudo-second-order model. In addition, the adsorption equilibrium isotherms were nonlinear and were well fitted by Freundlich and Langmuir models. It was found that the adsorption data on laterite, and paddy soil were better fitted by the Freundlich model; as for alluvial soil, the Langmuir model described it better. The maximum atrazine sorption capacities ranked as follows: paddy soil>alluvial soil>laterite. Results of thermodynamic calculations indicated that atrazine adsorption on three tested soils was spontaneous and endothermic. The desorption data showed that negative hysteresis occurred. Furthermore, lower solution pH value was conducive to the adsorption of atrazine in soils. The atrazine adsorption in these three tested soils was controlled by physical adsorption, including partition and surface adsorption. At lower equilibrium concentration, the atrazine adsorption process in soils was dominated by surface adsorption; while with the increase of equilibrium concentration, partition was predominant. Copyright © 2016. Published by Elsevier B.V.

Journal of Applied Science and Technology - Vol 17, No 1-2 (2012)

African Journals Online (AJOL)

... as partial replacement of portland cement in stabilizing laterites for road construction ... Synergetic effect of sulphur and nitrogen oxides on corrosion of galvanized ... Determination of radionuclides in discharged water from gold processing ...

Evaluation of Mercury Contamination in Fungi Boletus Species from Latosols, Lateritic Red Earths, and Red and Yellow Earths in the Circum-Pacific Mercuriferous Belt of Southwestern China.

Directory of Open Access Journals (Sweden)

Jerzy Falandysz

Full Text Available For the first time, highly elevated levels of mercury (Hg have been documented for several species of the edible Fungi genus Boletus growing in latosols, lateritic red earths, and red and yellow earths from the Yunnan province of China. Analysis of Hg concentrations in the genus suggests that geogenic Hg is the dominant source of Hg in the fungi, whereas anthropogenic sources accumulate largely in the organic layer of the forest soil horizon. Among the 21 species studied from 32 locations across Yunnan and 2 places in Sichuan Province, the Hg was found at elevated level in all samples from Yunnan but not in the samples from Sichuan, which is located outside the mercuriferous belt. Particularly abundant in Hg were the caps of fruiting bodies of Boletus aereus (up to 13 mg kg-1 dry matter, Boletus bicolor (up to 5.5 mg kg-1 dry matter, Boletus edulis (up to 22 mg kg-1 dry matter, Boletus luridus (up to 11 mg kg-1 dry matter, Boletus magnificus (up to 13 mg kg-1 dry matter, Boletus obscureumbrinus (up to 9.4 mg kg-1 dry matter, Boletus purpureus (up to 16 mg kg-1 dry matter, Boletus sinicus (up to 6.8 mg kg-1 dry matter, Boletus speciosus (up to 4.9mg kg-1 dry matter, Boletus tomentipes (up to 13 mg kg-1 dry matter, and Boletus umbriniporus (up to 4.9 mg kg-1 dry matter. Soil samples of the 0-10 cm topsoil layer from the widely distributed locations had mercury levels ranging between 0.034 to 3.4 mg kg-1 dry matter. In Yunnan, both the soil parent rock and fruiting bodies of Boletus spp. were enriched in Hg, whereas the same species from Sichuan, located outside the mercuriferous belt, had low Hg concentrations, suggesting that the Hg in the Yunnan samples is mainly from geogenic sources rather than anthropogenic sources. However, the contribution of anthropogenically-derived Hg sequestered within soils of Yunnan has not been quantified, so more future research is required. Our results suggest that high rates of consumption of Boletus spp. from

Evaluation of Mercury Contamination in Fungi Boletus Species from Latosols, Lateritic Red Earths, and Red and Yellow Earths in the Circum-Pacific Mercuriferous Belt of Southwestern China.

Science.gov (United States)

Falandysz, Jerzy; Zhang, Ji; Wang, Yuan-Zhong; Saba, Martyna; Krasińska, Grażyna; Wiejak, Anna; Li, Tao

2015-01-01

For the first time, highly elevated levels of mercury (Hg) have been documented for several species of the edible Fungi genus Boletus growing in latosols, lateritic red earths, and red and yellow earths from the Yunnan province of China. Analysis of Hg concentrations in the genus suggests that geogenic Hg is the dominant source of Hg in the fungi, whereas anthropogenic sources accumulate largely in the organic layer of the forest soil horizon. Among the 21 species studied from 32 locations across Yunnan and 2 places in Sichuan Province, the Hg was found at elevated level in all samples from Yunnan but not in the samples from Sichuan, which is located outside the mercuriferous belt. Particularly abundant in Hg were the caps of fruiting bodies of Boletus aereus (up to 13 mg kg-1 dry matter), Boletus bicolor (up to 5.5 mg kg-1 dry matter), Boletus edulis (up to 22 mg kg-1 dry matter), Boletus luridus (up to 11 mg kg-1 dry matter), Boletus magnificus (up to 13 mg kg-1 dry matter), Boletus obscureumbrinus (up to 9.4 mg kg-1 dry matter), Boletus purpureus (up to 16 mg kg-1 dry matter), Boletus sinicus (up to 6.8 mg kg-1 dry matter), Boletus speciosus (up to 4.9mg kg-1 dry matter), Boletus tomentipes (up to 13 mg kg-1 dry matter), and Boletus umbriniporus (up to 4.9 mg kg-1 dry matter). Soil samples of the 0-10 cm topsoil layer from the widely distributed locations had mercury levels ranging between 0.034 to 3.4 mg kg-1 dry matter. In Yunnan, both the soil parent rock and fruiting bodies of Boletus spp. were enriched in Hg, whereas the same species from Sichuan, located outside the mercuriferous belt, had low Hg concentrations, suggesting that the Hg in the Yunnan samples is mainly from geogenic sources rather than anthropogenic sources. However, the contribution of anthropogenically-derived Hg sequestered within soils of Yunnan has not been quantified, so more future research is required. Our results suggest that high rates of consumption of Boletus spp. from Yunnan can

Geotechnical Properties of Clayey Soil Stabilized with Cement ...

African Journals Online (AJOL)

ADOWIE PERE

2017-12-31

Dec 31, 2017 ... ... to investigate the different effects of cement-sawdust ash and cement on a ... Keywords: Cement, Saw dust, strength test subgrade material, highway construction ... characteristics of lateritic soil stabilized with sawdust ash.

investigation of shear strength parameters and effect of different

African Journals Online (AJOL)

HOD

Keywords: Coconut husk ash; Compaction; Lateritic soil; Lime; Shear strength; Stabilization. 1. INTRODUCTION ... the cementation or interlocking of the soil particles [5]. Furthermore, it is ... of its siliceous, aluminous and iron oxide content [8].

Erosion rates and landscape evolution of the lowlands of the Upper Paraguay river basin (Brazil) from cosmogenic 10Be

Science.gov (United States)

Pupim, Fabiano do Nascimento; Bierman, Paul R.; Assine, Mario Luis; Rood, Dylan H.; Silva, Aguinaldo; Merino, Eder Renato

2015-04-01

The importance of Earth's low sloping areas in regard to global erosion and sediment fluxes has been widely and vigorously debated. It is a crucial area of research to elucidate geologically meaningful rates of land-surface change and thus the speed of element cycling on Earth. However, there are large portions of Earth where erosion rates have not been well or extensively measured, for example, the tropical lowlands. The Cuiabana lowlands are an extensive low-altitude and low-relief dissected metamorphic terrain situated in the Upper Paraguay river basin, central-west Brazil. Besides exposures of highly variable dissected metamorphic rocks, flat residual lateritic caps related to a Late Cenozoic planation surface dominate interfluves of the Cuiabana lowlands. The timescale over which the lowlands evolved and the planation surface developed, and the rate at which they have been modified by erosion, are poorly known. Here, we present measurements of in situ produced cosmogenic 10Be in outcropping metamorphic bedrock and clastic-lateritic caps to quantify rates of erosion of the surface and associated landforms in order to better understand the Quaternary landscape evolution of these lowlands. Overall, slow erosion rates (mean 10 m/Ma) suggest a stable tectonic environment in these lowlands. Erosion rates vary widely between different lithologies (range 0.57 to 28.3 m/Ma) consistent with differential erosion driving regional landform evolution. The lowest erosion rates are associated with the low-relief area (irregular plains), where clastic-laterite (mean 0.67 m/Ma) and quartzite (mean 2.6 m/Ma) crop out, whereas the highest erosion rates are associated with dissection of residual hills, dominated by metasandstone (mean 11.6 m/Ma) and phyllite (mean 27.6 m/Ma). These data imply that the Cuiabana lowland is comprised of two dominant landform sets with distinct and different dynamics. Because the planation surface (mostly lowlands) is lowering and losing mass more

Very low frequency electromagnetic (VLF-EM) and electrical resistivity (ER) investigation for groundwater potential evaluation in a complex geological terrain around the Ijebu-Ode transition zone, southwestern Nigeria

International Nuclear Information System (INIS)

Osinowo, Olawale O; Olayinka, A Idowu

2012-01-01

Groundwater exploration in either a basement or sedimentary environment is often fairly well defined and focuses on delineating weathered/fractured rocks or saturated formations, respectively. Conversely, unique geological structures, the complex coexistence of different rock types and poorly defined basal/lateral contacts between basement and sedimentary rocks make groundwater development in a geological transition environment very challenging. Ijebu-Ode and its environs lie within such a problematic transition zone, between the Precambrian basement rocks and Cretaceous sediments of the Dahomey Basin, in southwestern Nigeria, where associated acute groundwater development challenges require adequate subsurface information to maximize its groundwater resource potential. This study integrated very low frequency electromagnetic (VLF-EM) and electrical resistivity (ER) geophysical prospecting techniques for a detailed terrain study of Ijebu-Ode in order to establish the reasons for the low groundwater resource potential in the area. Thirty five VLF-EM profiles, 140 vertical electrical soundings (VES) and relevant hydrogeological data were acquired along grids and profiles. Data were filtered, inverted and enhanced using appropriate software packages. The current density and geoelectric parameters of the VLF-EM and VES data were employed to generate terrain maps, the conductivity distribution and a subsurface basement model of the study area. Current density plots and geoelectric parameters identified up to three layers in the basement complex terrain which comprised lateritic topsoil, weathered basement and fresh basement rocks. The five layers encountered in the sedimentary terrain were topsoil, a lateritic unit, a dry sandy unit, a saturated sandy unit and fresh basement rocks. The hydraulic conductivity of the thick (3–18 m) lateritic unit was determined to be 1.32 × 10 −5 mm s −1 , while that of the underlying sandy units ranged from 2.65 × 10 −4 to 1

Geochemical and Geophysical Study in a Degraded Area Used for Disposal of Sludge from a Water Treatment Plant

International Nuclear Information System (INIS)

Moreira, R.C.A.; Nunes, S.A.; Da Silva, D.R.; Lira, C.P.; Boaventura, G.R.; Do Nascimento, C.T.C.; Moreira, R.C.A.; Pinheiro, L.A.

2011-01-01

The effects of disposal of sludge from water treatment plant (WTS) in area damaged by laterite extraction and its consequences to soil and groundwater were investigated. Therefore, the presence and concentration of anthropogenic elements and chemical compounds were determinated. WTS disposal's influence was characterized by electroresistivity method. The WTS's geochemical dispersion was noticed in the first meters of the non saturated zone from the lending area. Lateritic profiles were characterized due to the large variation in chemical composition between the horizons. Infiltration and percolation of rainwater through the WTS have caused migration of total dissolved solids to the groundwater. WTS's disposing area has more similarities to local preserved vegetation than to gravel bed area. WTS can be considered a noninert residue if disposed in degraded areas located in regions with similar geological and hydrochemical characteristics.

Land-surface evolution at the continental time-scale: An example from interior Western Australia

Science.gov (United States)

Mabbutt, J. A.

1988-12-01

The interior plateau of Western Australia in the Wiluna—Meekatharra area is in part an exhumed pre-Permian surface of low relief and to that extent of Gondwana age. A lateritic duricrust on interfluvial remnants of an Old Plateau surface is probably the outcome of several cycles of weathering and stripping, rather than of a single geomorphic episode. Landforms above the Old Plateau have maintained their relief during this circumdenudation and there is no regional evidence of their isolation by major escarpment retreat. A New Plateau surface has extended by stripping of saprolite and is an etchplain, as also is the Old Plateau under the genesis postulated. The New Plateau cycle was initiated by general drainage rejuvenation whilst lateritic weathering still continued, but its extension was halted through increasing climatic aridity, probably during the Miocene.

Global Journal of Engineering Research - Vol 14, No 1 (2015)

African Journals Online (AJOL)

Compressive and flexural strength of cement mortar stabilized with raffia palm fruit ... Effect of compactive effort on strength indices of laterite treated with calcium ... Engineering properties of scoria concrete as a construction material · EMAIL ...

Global Journal of Pure and Applied Sciences - Vol 20, No 1 (2014)

African Journals Online (AJOL)

Effects of abattoir wastes on benthic macroinvertebrates of the Elechi creek, Port ... Stabilization of Ikpayongo laterite with cement and calcium carbide waste ... husk ash and termite hill types on the physical and mechanical properties of burnt ...

mathematical model for the optimization of compressive strength

African Journals Online (AJOL)

ES Obe

cement and sand either wholly or partially without adverse effect on the strength properties of the ... sandcrete block, compressive strength, laterite, scheffe's theory. 1. Introduction ... that for the properties of a q-component mix- ture which ...

Phosphate acquisition efficiency and phosphate starvation tolerance ...

Indian Academy of Sciences (India)

3Department of Genetics and Plant Breeding, College of Agriculture, Lembucherra, Tripura 799 ... vated in soil like red and lateritic or acid, with low soluble phosphate content. ..... activation of genes involved in the adaptation of Arabidopsis to.

The Influence of Unusual Materials as Prospective Fillers in the Hot Mix Asphalt

Science.gov (United States)

Cavalcate Ferrão, Wallace; Moizinho, Joel Carlos

2017-10-01

Among the factors that influence directly the durability of the asphaltic layer on pavements, the type and percentage of filler in the hot mix asphalt pavement (HMA) is a great player. The most traditional fillers, the Portland cement and the hydrated lime, are well known for resisting to weather variations and adding extra features to the hot mixtures. The glass powder, the cladding waste (gotten from clay bricks), the ashes of rice husks and laterite powder are proposed as substitutes to the traditional ones. The materials have been sieved and classified by fitting the powder on the filler grain size required by Brazilian Rules, eventually they have been tested with asphalt 50/70. The glass powder performed a Thermic Susceptibility Index (IST) of -0.69 for 5% in weight of filler and -0.75 for 10% in weight of filler, proving that this material satisfies the Brazilian specification DNIT-EM 095/2006; on the other hand, the laterite powder presented an IST of -0.61 for 5% and 0.32 for 10%. After executing the Softening Point, Penetration and Flash Point tests, it has been confirmed that the glass and laterite powder are recommended materials as potential substitutes to the Portland cement, however the first one performs better under balmy temperatures due to its negative IST; the cladding powder and the rice husks turns the mixtures too rigid and breakable on percentages close to 10%.

Browse Title Index

African Journals Online (AJOL)

Vol 6, No 3 (2000), Software development and intellectual property laws in Nigeria. .... serum bilirubin in Calabar, a tropical region: time, light and temperature effect. ... Vol 20, No 1 (2014), Stabilization of Ikpayongo laterite with cement and ...

Immobilization of As, Cr and Cu in CCA Contaminated soil using ...

African Journals Online (AJOL)

HP USER

with increase in the level of amendment application, was higher for termitaria than for laterite and was Cu ... Heavy metal uptake by maize generally reflected the soluble/mobile pool and ..... thesis, University of Benin, Benin City (2009). 11.

models for predicting compressive strength and water absorption

African Journals Online (AJOL)

user

presents a mathematical model for predicting the compressive strength and water absorption of laterite-quarry dust cement block using ... building and construction of new infrastructure and .... In (6), R is a vector containing the real ratios of the.

Preservation and concentration of uranium mineralization in the crust of weathering

International Nuclear Information System (INIS)

Ashikhmin, A.A.; Kuznetsov, S.V.; Shmarovich, E.M.

1983-01-01

Inprecision of the concept on indispensable evacuation of U from ores during formation of the crust of weathering of lateritic or kaolinitic profile due to the existence of oxidative situation in the crusts is established. At hydrothermal uranium deposit in Eocambrian sandy-shaly and Paleozoic volcanogenous-sedimentary rocks a high degree of mineralization preservation in lower and medium horizons of Mesozoic-Cenozoic hydro-micaceous-kaolinitic crust of weathering, characterized by reductive situation, presence of carbonaceous substance, pyrite and siderite, is established. Mineralization attained there black composition and was additionally enriched with uranium. A supposition is made that the case is specific for the development of lateritic and kaolinitic crust formation according to ore-bearing rocks, rich in reducing agents-carbonaceous substances, sulfides and minerals of protoxidic iron. The data obtained should be taken into account during prediction and prospecting activities

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Items 301 - 350 of 1011 ... ... Model of Lateritic Hollow Block With 4% Mound Soil Inclusion, Abstract PDF ... Vol 31, No 3 (2012), Digital Control of External Devices through the ... Vol 35, No 2 (2016), DURABILITY OF FLEXIBLE PAVEMENTS: A ...

Assessment of Bagasse Ash Effect on the California Bearing Ratio of ...

African Journals Online (AJOL)

Laboratory tests were performed on the natural and bagasse ash treated soil samples ... on the natural lateritic soil shows that it falls under Silt-Clay material of Group A-6 ... by the Nigerian general specification (1997) for cement stabilization.

Author Details

African Journals Online (AJOL)

Comparative Analysis of the Compressive Strength of Concrete with Gravel and Crushed Over Burnt Bricks as Coarse Aggregates ... Stratification in Waste Stabilization Ponds I: Effects on Pond Parameters ... Engineering CLASSICAL OPTIMIZATION OF BAGASSE ASH CONTENT IN CEMENT-STABILIZED LATERITIC SOIL

Provenance Studies Through Petrography and Heavy Mineral

African Journals Online (AJOL)

USER

are also cement and voids. These four parameters make up the bulk textural properties of any ..... tidal effect held sway.The field work ... Laterites.Geol.Surv. Nigeria Rept. No. 1027. nd. Folk, R. L. 1974.Petrology of Sedimentary Rocks (2.

Ghana Mining Journal - Vol 14 (2013)

African Journals Online (AJOL)

Understanding Lateritic Ore Agglomeration Behaviour as a Precursor to Enhanced Heap Leaching · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. J Addai-Mensah, I Quaicoe, A Nosrati, DJ Robinson, 41-50 ...

influence of superplasticizer and varying aggregate size

African Journals Online (AJOL)

HOD

The research findings presented show that laterite .... results support the research findings of Neville(13); ... Design of Concrete Structures 14th Edition, NY, McGraw-. Hill. [3] Neville, A.M.. ... [13] Neville, A. M. Properties of Concrete, 4th Edition,.

temperature effect on water absorption in an improved periwinkle ...

African Journals Online (AJOL)

Nwokem et al.

Adding a reinforcement into a laterite soil as a building material is one of the ... meet building standard. Omubo-Pepple et al .... Journal of Issues in Professional Teachers Education. 3: 151-160. ... Journal of Applied Physics, 70, 1160-1165. 3.

Modes, tempo and spatial variability of Cenozoic cratonic denudation: morphoclimatic constraints from West Africa

Science.gov (United States)

Beauvais, Anicet; Chardon, Dominique

2010-05-01

After the onset of Gondwana break-up in the Early Mesozoic, the emerged part of the African plate underwent long Greenhouse effect climatic periods and epeirogeny. The last Greenhouse effect period in the Early Cenozoic and the alternation of wet and dry climatic periods since the Eocene enhanced episodes of rock chemical weathering and laterite production, forming bauxites and ferricretes, interrupted by drier periods of dominantly mechanical denudation, shaping glacis [1]. In Sub-Saharan West Africa, this evolution resulted in pulsate and essentially climatically-forced denudation that has shaped an ubiquitous sequence of five stepped lateritic paleosurfaces that synchronously developed over Cenozoic times. The modes, timing and spatial variability of continental denudation of the region are investigated by combining geomorphologic and geochronological data sets. The geomorphologic data set comprises the altitudinal distribution of the lateritic paleosurfaces relicts and their differential elevation from 42 locations in Sub-Saharan West Africa where the sequence (or part of it) has been documented. The geochronological data set consists in the age ranges of each paleosurface tackled by radiometric 39Ar-40Ar dating of the neoformed oxy-hydroxides (i.e., cryptomelane, K1-2Mn8O16, nH2O, [4]) carried by their laterites at the Tambao reference site, Burkina Faso [1, 3]. Five groups of 39Ar-40Ar ages, ~ 59 - 45 Ma, ~ 29 - 24 Ma, ~ 18 - 11.5 Ma, ~ 7.2 - 5.8 Ma, and ~ 3.4 - 2.9 Ma, characterize periods of chemical weathering whereas the time laps between these groups of ages correspond to episodes of mechanical denudation that reflect physical shaping of the paleosurfaces. For the last 45 Ma, the denudation rate estimates (3 to 8 m Ma-1) are comparable with those derived on shorter time scale (103 to 106 y.) in the same region by the cosmogenic radionuclide method [2]. Combined with the geomorphologic data set, these age ranges allow the visualization of the regional

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Items 51 - 100 of 299 ... Vol 1, No 1 (1996), Chemical properties of some indigenous building ... shell ashes as partial replacement of portland cement in stabilizing laterites for .... Vol 20, No 1-2 (2015), Effect of irregularity and inhomogenity on the ...

prediction of flexural strength of chikoko pozzolana blended cement

African Journals Online (AJOL)

user

optimize the flexural strength of chikoko pozzolana blended cement concrete using Osadebe's regression function. The ... such as cement [1-3]. Nigeria is blessed with abundance of local building and construction materials such as stones, sand, laterite and timber. However ...... Soil Stabilization”, International Journal of.

Bauxite formation on Tertiary sediments and Proterozoic bedrock in Suriname

NARCIS (Netherlands)

Monsels, D.A.

2018-01-01

The lateritic bauxite deposits in Suriname are traditionally distinguished into Coastal plain bauxites and Plateau bauxites, a subdivision that is primarily based on their topographic and geographic position. The first group is located in the lowlands of the coastal plain, while the second group is

Studies on the Effect of Rice Husk Ash as Cement Admixture * M.U ...

African Journals Online (AJOL)

acer

Studies on the Effect of Rice Husk Ash as Cement Admixture. *. 1. M.U Dabai,. 1 ... production of durable concrete and at the same time it is a ... indigenous and waste, materials in concrete. One .... (4.08%). The Iron oxide may be from laterite.

Mechanical Properties of Millet Husk Ash Bitumen Stabilized Soil ...

African Journals Online (AJOL)

Akorede

lateritic soil blocks using Millet Husk Ash (MHA) and Bitumen as additives so as to reduce its high cost and find ... eliminating the need for air-conditioning and are warm during the cold ... The mix properties were used in producing soil bricks of ...

Mineralogy and Sr–Nd isotopes of SPM and sediment from the Mandovi and Zuari estuaries: Influence of weathering and anthropogenic contribution

Digital Repository Service at National Institute of Oceanography (India)

Rao, V.P.; Shynu, R.; Singh, S.K.; Naqvi, S.W.A.; Kessarkar, P.M.

downstream in both estuaries. Smectite contents were much higher in Zuari than in Mandovi estuary. The ⁸⁷Sr/⁸⁶Sr ratios and _{error terms}Nd of SPM were higher than those in hinterland rocks and laterite soils. The Sr ratios were...

Author Details

African Journals Online (AJOL)

Modelling of California Bearing Ratio with Unconfined Compressive Strength for Cement Stabilized Laterite Soil Abstract · Vol 30 (2015) - Articles A Mathematical Model for the Comparative Study of the Blast Response of Aluminium and Steel Panels Abstract · Vol 30 (2015) - Articles Modelling Convergence of Finite ...

Utilisation of rice husk ash for improvement of deficient soils in Nigeria

African Journals Online (AJOL)

The studies generally showed improvement in the geotechnical properties of soils, either modified or stabilised with the ash, thus indicating the potentials of using this agricultural waste for improvement of geotechnical properties of ... Keywords: Black cotton soil, Deficient soil, Laterite, Rice husk ash, Soil improvement ...

Integrated geophysical investigation of the Igbara-Oke – Igbaraodo ...

African Journals Online (AJOL)

Along the failed segments, relatively thin (< 1.5 m) or non existing lateritic subgrade; low resistivity weathered layer(< 151 ohm-m);H type curve starting with decreasing resistivity typical of incompetent substratum and subsurface geological structures suspected to be faults, fractures, joints or lithologic boundaries ...

Cocoa pod and palm kernel shell ashes as partial replacement of ...

African Journals Online (AJOL)

The laterites exhibited plasticity indices < 12 % and liquid limits < 45 %, thereby conforming to UK Transport Research Laboratory and Nigerian Federal Ministry of Works Specifications for Roads and Bridges. The additives could serve as partial replacement of cement because of the strength and durability properties, and ...

L'or, le zircon et la tourmaline : Traceurs de l'origine des materiaux ...

African Journals Online (AJOL)

The thick lateritic cover of tropical zones are often considered as old soils which have undergone several evolutionary cycles throughout time. Nevertheless, they contain some resistant minerals like gold, zircon and tourmaline which remain after surficial processes.These residual minerals, used as tracers of the genesis ...

Author Details

African Journals Online (AJOL)

Onyelowe, KC. Vol 31, No 3 (2012) - Articles Technical Note: Geotechnical Examination of the Geophysical Properties of Olokoro Borrow Site Lateritic Soil for Road Works Abstract PDF · Vol 34, No 3 (2015) - Agricultural, Bioresources, Biomedical, Food, Environmental & Water Resources Engineering Modeling the Effect of ...

The alpha activity of soils in relation to landscape development

Energy Technology Data Exchange (ETDEWEB)

Pepper, R G; Quirk, J P [Western Australia Univ., Nedlands. Dept. of Soil Science and Plant Nutrition

1976-02-01

The alpha activity of soils and the degree of the equilibrium of the thorium series has been related to the age of soils developed on a truncated laterite landscape in southwestern Australia. The uplift of the old lateritic plateau has formed a sequence of erosional and depositional surfaces which form the parent materials of the present-day soils. These surfaces because of their different relative ages have been subjected to different degrees of weathering and leaching. The alpha activity of the soils formed on these different landscape surfaces is influenced firstly by the amount of weathering that the surface has undergone, and secondly by the degree of leaching that the soil has undergone as evidenced by profile development. It has been found that the younger soils have higher alpha activities with the thorium series tending more towards equilibrium when compared with older soils, where the alpha activity is lower due to the leaching of the daughter nuclides from the profile.

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Items 551 - 600 of 985 ... Vol 30 (2015), Modelling Monthly Mental Sickness Cases Using Principal Component Regression Method, Abstract. Patrick O Aye. Vol 18 (2011), Modelling of California Bearing Ratio with Unconfined Compressive Strength for Cement Stabilized Laterite Soil, Abstract. SD Iyeke, SO Osuji. Vol 12 (2008) ...

Nigerian Journal of Technology - Vol 28, No 1 (2009)

African Journals Online (AJOL)

Effects of Rice Husk Ash on Some Geotechnical Properties of Lateritic Soil · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL ... Formula for Forced Vibration Analysis of Structures Using Static Factored Response as Equivalent Dynamic Response · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT

AJET VOL. 9. NO. 1 arrangement Backup New Correction

African Journals Online (AJOL)

Ayodele Azeez A

Design Firms which identified major factors responsible for poor performance of the firms. Adedayo, Oyetola, Offiah and Adebayo ... A comparative study of compressive strength of cement laterite brick produced with rice husk and wood ash as partial replacements of cement was carried out by Dahiru, Mamman and Usman.

Nigerian Journal of Technology - Vol 28, No 2 (2009)

African Journals Online (AJOL)

Effects of Compaction Delay on the Properties of Cement-Bound Lateritic Soils · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL TEXT ... Stability of Axially Compressed Single-Cell Mono-Symmetric Thin-Walled Closed Column · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL ...

Models for predicting compressive strength and water absorption of ...

African Journals Online (AJOL)

This work presents a mathematical model for predicting the compressive strength and water absorption of laterite-quarry dust cement block using augmented Scheffe's simplex lattice design. The statistical models developed can predict the mix proportion that will yield the desired property. The models were tested for lack of ...

Contamination of boreholes water by 76 pesticides molecules in the ...

African Journals Online (AJOL)

user2

to be the cause of the degradation of the quality of sur- face and ground waters ... network and the nature of the soil generally clay lateritic with high permeability. .... 0.006 0.008 0.004 0.004 0.004 0.007 0.008 0.004 0.004 0.004 Malathion.

Journal of Applied Science, Engineering and Technology - Vol 3, No ...

African Journals Online (AJOL)

Some geotechnical properties of a cement-stabilized granite-gneiss-derived lateritic soil from Ile-Ife, Southwestern Nigeria · EMAIL FULL TEXT EMAIL FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. GO Adeyemi, RA Owosanya, FC Anokwu, 8-12. http://dx.doi.org/10.4314/jaset.v3i2.38243 ...

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Items 51 - 100 of 132 ... Vol 39, No 2 (2003), Geophysical investigation for groundwater around ... Vol 38, No 1 (2002), Geotechnical properties of lateritic soil ... Vol 42, No 1 (2006), Hydrocarbon charge in petroleum systems of the Niger Delta, Nigeria, Abstract ... Vol 40, No 2 (2004), Mineralogical, chemical and industrial ...

Aspects of Geophysical Exploration for Groundwater Using Vertical ...

African Journals Online (AJOL)

MICHAEL HORSFALL

3666.4m); wet laterite, (44.017-2201m); anomalous soil, (601.03-. 1450m); clayed/silty sand, (2712.38-11741m); dry sand, and (2909.7-12423m); as aquifer. The results reveal depth to water table ranges of 31.2-65.5m. The range of values of.

The use of agricultural waste materials for concrete making ...

African Journals Online (AJOL)

This paper presents laterite as fine aggregate and agricultural waste materials such as periwinkle shell, (PS) and palm kernel shell (PKS) as coarse aggregate for making concrete. Saturated surface dry (SSD) bulk density and compressive cube strength tests of concrete made from these were carried at the concrete age of ...

YOUTH EMPLOYMENTin Rwanda

International Development Research Centre (IDRC) Digital Library (Canada)

For more information, please refer to Laterite Ltd. (2015) Youth employment in Rwanda: A scoping paper, commissioned by IDRC and the MasterCard Foundation. 13.5% of Rwandans with a university degree are unemployed– 7 times the national unemployment rate. Among the economically inactive, more than 1 in 5 ...

Journal of Mining and Geology - Vol 41, No 1 (2005)

African Journals Online (AJOL)

Mineralogy and geochemistry of lateritic weathering profiles on ultramafic rock bodies around Mokuro in Ile-Ife area, southwestern Nigeria · EMAIL FULL TEXT EMAIL FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. OA Ige, B Durotoye, AE Oluyemi, 11-18. http://dx.doi.org/10.4314/jmg.v41i1.18825 ...

Journal of Earth System Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

In the Deccan region of western India ferricrete duricrusts,usually described as laterites,cap some basalt summits east of the Western Ghats escarpment,basalts of the low-lying Konkan Plain to its west,as well as some sizeable isolated basalt plateaus rising from the Plain. The duricrusts are iron-cemented saprolite with ...

Author Details

African Journals Online (AJOL)

Addai-Mensah, J. Vol 14 (2013) - Articles Understanding Lateritic Ore Agglomeration Behaviour as a Precursor to Enhanced Heap Leaching Abstract PDF. ISSN: 0855-210X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms ...

Lithology and economic potential resource of Igumale-Nsukka area ...

African Journals Online (AJOL)

The sandstones are used in the manufacturing of glass while laterites are used for various construction purposes such as roads, buildings and bridges. The clays are for pottery, glazed tiles, in ceramics industry. The coal has a future prospect for industries, such as iron and steel industry as cooking coal, cement industries ...

Effect of selected factors on the current flow and voltage loss at ...

African Journals Online (AJOL)

In this paper, laboratory scale study was conducted to investigate the current flow and voltage loss at the electrodes in the electrochemical treatment of a tropical laterite. Three different tests using calcium chloride (CC) as anolyte and sodium chloride (SC) as catholyte (NC); SC as anolyte and Phosphoric acid (PA) as ...

Magnetic fabrics and fluid flow directions in hydrothermal systems. A case study in the Chaillac Ba-F-Fe deposits (France)

Science.gov (United States)

Sizaret, Stanislas; Chen, Yan; Chauvet, Alain; Marcoux, Eric; Touray, Jean Claude

2003-02-01

This study presents a possible use of anisotropy of magnetic susceptibility (AMS) to describe the mineralizing process in hydrothermal systems. Ba-F-Fe-rich deposits within the Chaillac Basin are on the southern border of the Paris Basin. In these deposits hydrothermal textures and tectonic structures have been described in veins, sinters, and sandstone cemented by hydrothermal goethite. 278 oriented cores from 24 sites have been collected in these formations. In addition, a lateritic duricrust superimposed on the hydrothermal formation has been sampled. Rock magnetic investigations show that the principal magnetic carrier is goethite for the hydrothermal mineralization and for the laterite level. The AMS measurements show distinguishable behaviors in the different mineralogical and geological contexts. The K1 magnetic lineation (maximum axis) is strongly inclined for the vertical veins. For the horizontally mineralized sinters, the magnetic lineation is almost horizontal with an azimuth similar to the sedimentary flow direction. The AMS of goethite-rich sandstone close to the veins shows strongly inclined K1 as they are probably influenced by the vertical veins; however, when the distance from the vein is larger than 1 m, the AMS presents rather horizontal K1 directions, parallel to the sedimentary flow. The laterite has a foliation dominance of AMS with vertically well-grouped K3 axes and scattered K1 and K2 axes. Field structural observations suggest that the ore deposit is mainly controlled by EW extension tectonics associated with NS trending normal faults. Combining the AMS results on the deposit with vein textures and field data a model is proposed in which AMS results are interpreted in terms of hydrothermal fluid flow. This work opens a new investigation field to constrain hydrodynamic models using the AMS method. Textural study combined with efficient AMS fabric measurements should be used for systematic investigation to trace flow direction in fissures

Evaluation of Strength Characteristics of Laterized Concrete with Corn Cob Ash (CCA) Blended Cement

Science.gov (United States)

Ikponmwosa, E. E.; Salau, M. A.; Kaigama, W. B.

2015-11-01

Agricultural wastes are dumped in landfills or left on land in which they constitute nuisance. This study presents the results of investigation of strength characteristics of reinforced laterized concrete beams with cement partially replaced with corn cob (agricultural wastes) ash (CCA). Laterized concrete specimen of 25% laterite and 75% sharp sand were made by blending cement with corn cob ash at 0 to 40% in steps of 10%. A concrete mix ratio of 1:2:4 was used to cast 54 cubes of 150×150×150mm size and 54 beams of dimension 750×150×150mm. The results show that the consistency and setting time of cement increased as the percentage replacement of cement with CCA increased while the workability and density of concrete decreased as the percentage of CCA increased. There was a decrease in compressive strength when laterite was introduced to the concrete from 25.04 to 22.96N/mm2 after 28 days and a continual reduction in strength when CCA was further added from 10% to 40% at steps of 10%. Generally, the beam specimens exhibited majorly shear failure with visible diagonal cracks extending from support points to the load points. The corresponding central deflection in beams, due to two points loading, increased as the laterite was added to the concrete mix but reduced and almost approaching that of the control as 10% CCA was added. The deflection then increased as the CCA content further increased to 20%, 30% and 40% in the mix. It was also noted that the deflection of all percentage replacement including 40% CCA is less than the standard recommended maximum deflection of the beam. The optimal flexural strength occurred with 10% CCA content.

Geochemical evidences for palaeoclimatic fluctuations at the Triassic-Jurassic boundary: southwestern margin of the Neotethys in the Salt Range, Pakistan

Science.gov (United States)

Iqbal, Shahid; Wagreich, Michael; Jan, Irfanullah; Kürschner, Wolfram Michael; Gier, Susanne

2017-04-01

The Triassic-Jurassic boundary interval reveals a change from warm-arid to a warm and humid climate in the Tethyan domain. Sea-level reconstruction records across the European basins during this interval reveal an end-Triassic global regression event and is linked to the Central Atlantic Magmatic Province (CAMP) activity and Pangaea breakup. In the Tethyan Salt Range of Pakistan a succession of Upper Triassic dolomites/green-black mudstones (Kingriali Formation), overlying quartzose sandstone, mudstones, laterites and Lower Jurassic conglomerates/pebbly sandstones (Datta Formation) provides information on the palaeoclimatic evolution of the area. Preliminary palynological results from the mudstones indicate a Rhaetian age for the Kingriali Formation and a Hettangian age for the Datta Formation. X-ray diffraction (XRD) analysis of the mudstones (upper part of the Kingriali Formation) indicates the presence of mainly illite while kaolinite is a minor component. The kaolinite content, a reflection of the advanced stage of chemical weathering and hence warm-humid conditions, increases up-section in the overlying sandstone-mudstone succession. The overlying laterite-bauxite horizons lack illite/smectite and are entirely composed of kaolinite, boehmite and haematite. At places these kaolinite rich horizons are mined in the area (Western Salt Range). The bulk rock geochemistry of the succession confirms a similar trend. The Chemical Index of Alteration (CIA) displays an increasing trend from the Upper Triassic shales (CIA 75-80) through the overlying sandstones/mudstones-laterites to the overlying quartz rich sandstones and mudstones (CIA 90-97). The overall results for the succession reveal an increasing chemical maturity trend (increase in the intensity of chemical weathering) from Rhaetian to Hettangian thereby supporting a change from warm-arid to a warm-humid palaeoclimate, probably extreme greenhouse conditions.

Browse Title Index

African Journals Online (AJOL)

Items 101 - 150 of 228 ... Vol 5, No 1 (2007), Laboratory modelling of the electrical resistivity response of Near-surface geological contacts, Abstract. H O Ogundipe, A I Idornigie, M O Olorunfemi. Vol 9, No 1 (2011), Lateritic weathering of granite-gneiss in Obudu Plateau, south eastern Nigeria, Abstract PDF. FA Ushie, OL Anike.

Modeling of 1-D nitrate transport in single layer soils | Dike | Journal ...

African Journals Online (AJOL)

The transport of nitrate in laboratory single soil columns of sand, laterite and clay were investigated after 21 days. The 1-D contaminant transport model by Notodarmojo et al (1991) for single layer soils were calibrated and verified using field data collected from a refuse dump site at avu, owerri, Imo state. The experimental ...

Browse Title Index

African Journals Online (AJOL)

Items 1 - 50 of 289 ... Vol 1, No 3 (2001), Basic home range characteristics for the conservation of the African grey parrot in the Korup national park, Cameroon, Details PDF. SA Tamungang, IA Ayodele, ZE Akum. Vol 7, No 3 (2008), Behaviour of palladium in three lateritic profiles developed on serpentinites of the Lomie ...

Understanding Lateritic Ore Agglomeration Behaviour as a ...

African Journals Online (AJOL)

Processing such ores through cost-competitive heap (4-10 m high) leaching as an alternative, requires successful agglomeration of the feed into robust and porous granules. To date, produc-ing of granules with desirable attributes poses a major geotechnical challenge to industry. In the present work, we investigate ...

compaction and consolidation characteristics of lateritic soil

African Journals Online (AJOL)

user

SOIL OF A SELECTED SITE IN IKOLE EKITI, SOUTHWEST NIGERIA. A. Bolarinwa1,*, J. B. ... various locally available materials for stabilization/ improvement of some .... attempted but futile as some of the clays were too sandy to stay in the ...

Mineralogical aspects of the laterites of Maicuru

International Nuclear Information System (INIS)

Lemos, V.P.; Costa, M.C. da

1989-01-01

This paper presents the prelimary mineralogical data of the weathering materials derived from the alkaline-ultramafic-carbonatitic Maicuru complex, State of Para. These material include several minerals species: iron, titanium and aluminium oxides/hydroxides as aluminous goethite, geothite, hematite, maghemite, lepidocrocite, anatase; and gibbsite; clay minerals of the smectite, chlorite, vermiculite and kaolinite groups and interstratified chlorite-smectite, mica-vermiculite, vermiculite-chlorite and Kaolinite-smectite; and aluminous phosphates of the crandalite group, wardite, augelite, senegalite, wavelite and variscite. The principal characteristics of these minerals were obtained by X-ray diffraction, optical methods, electron probe microanalysis, energy dispersive scanning electron microscope, X-ray fluorescence, atomic absorption, inductively coupled plasma-ICP source spectrometry and colorimetric methods. (author) [pt

A New Direction for Biomining: Extraction of Metals by Reductive Dissolution of Oxidized Ores

Directory of Open Access Journals (Sweden)

Kevin B. Hallberg

2013-01-01

Full Text Available Biomining, the biotechnology that uses microorganisms to extract metals from ores and concentrates, is currently used exclusively for processing reduced ores and mine wastes. Metals of economic value also occur extensively in oxidized ores, such as nickel laterites. While these are not amenable to oxidative dissolution, the ferric iron minerals they contain can, in theory, be disrupted by iron reduction, causing associated metals to be released. We have harnessed the ability of the facultatively anaerobic, acidophilic bacterium Acidithiobacillus ferroooxidans to couple the oxidation of elemental sulphur to the reduction of ferric iron in the goethite fraction of a limonitic nickel ore at 30 °C. Nickel and other metals (Co, Cr and Mn were effectively solubilised and maintained in solution due to the low pH (1.8 of the leach liquor. The results highlight the potential for the bioprocessing of oxidized, iron-rich ores using an approach that is energy-saving and environmentally-benign compared with metallurgical processes currently applied to the extraction of Ni from lateritic ores.

Isotopic tracer studies to evaluate relative efficiency of different forms of P for growing rice on different soil types

Energy Technology Data Exchange (ETDEWEB)

Dash, R N; Mohanty, S K; Patnaik, S [Central Rice Research Inst., Cuttack (India)

1977-12-01

The relative efficiency of different forms of P in relation to their time of application for growing rice on different soil types has been studied by using /sup 32/P tagged mono-, di-, and tri-calcium phosphate, ammonium nitrate phosphate containing all the P in the citrate-soluble form and potassium meta-phosphate. P-deficient acid laterite soil from Burdwan, red loam soil from Peramanpur and calcareous black soil from Hyderabad were used in the study. The different P forms were found to be compatible in the acid, red and laterite soils when the phosphorus forms were primed to moist acid soils 2 weeks prior to flooding. On application at flooding, fertilizers containing citrate-soluble phosphate were found to be less effective as compared to those containing water-soluble phosphate. In the calcareous black soil, however, the fertilizers, containing insoluble or citrate-soluble phosphates were not as efficient as the water-soluble forms, possibly because of lack of dissolution process. Potassium meta-phosphate was found to be effective in all the soil types whether applied at flooding or primed to the moist soil.

Nigerian Journal of Technology - Vol 34, No 1 (2015)

African Journals Online (AJOL)

Development of Optimized Strength Model of Lateritic Hollow Block With 4% Mound Soil Inclusion · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT ... http://dx.doi.org/10.4314/njt.v34i1.4 ... Performance of Jatropha Oil Blends in RD270 Two Cylinders Four Stroke Diesel Engine. GA Duvuna, AA ...

Journal of Earth System Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Earth System Science; Volume 117; Issue 5. Volume 117, Issue 5. October 2008, pages 537-645. pp 537-551. The High Deccan duricrusts of India and their significance for the 'laterite' issue · Cliff D Ollier Hetu C Sheth · More Details Abstract Fulltext PDF. In the Deccan region of western India ...

Comparative uptake of gamma-emitting fission product nuclides by plants

International Nuclear Information System (INIS)

D'souza, T.J.; Mistry, K.B.

1974-01-01

The comparative uptake of long-lived gamma-emitting fission product nuclides 106 Ru, 125 Sb, 137 Cs and 144 Ce, present in global fallout from nuclear explosions, by maize (Zea mays L) plants was examined in water culture experiments. Over identical duration of plant growth, the extent of accumulation of the radionuclides in aerial tissues was in the following decreasing order: 137 Cs >, 125 Sb >, 106 Ru > and 144 Ce. In roots, however, the retention of 144 Ce and 106 Ru was greater than that of 137 Cs and 125 Sb. Complementary studies with maize and rice (Oryza sativa L) grown on two contrasting soil types, namely, laterite and black clay loam indicated that 137 Cs uptake by plants was markedly greater than that of the other radionuclides in both soil types. Plant uptake of 106 Ru and 125 Sb was significantly higher than that of 144 Ce in the black soil. In the laterite, however, 144 Ce uptake far exceeded that of 106 Ru and 125 Sb. In general, maize removed higher amounts of the radionuclides than rice from both soil types. (author)

The Elemental content of Niue Island soils as an indicator of their origin

International Nuclear Information System (INIS)

Whitehead, N.E.

1993-01-01

The major and trace element contents of 241 Niue Island lateritic soils were determined, mainly by X-ray fluorescence, to deduce soil origins. The analyses showed very low SiO 2 content, and a high content of Mg, P, V, Cr, Sr, Y, Hg, and α-counts, compared with other laterites worldwide. The distribution patterns are consistent with derivation by weathering from calcite and dolomite rather then from deposted volcanic ash. Weathering is a particularly novel explanation for the origin of the relatively high content of P in these soils. The soils contain a negative Ce anomly, consistent with an origin from seawater or coral, but not volcanic ash. If recent results showing in situ formation of magnetite in soils are applicable, the soil mineralogy is wholly from calcite is also consistent with the relative lack of volcanic ash on the seabed nearby, and very low deposition of aeolian dust. The radioactivity content is consistent neither with calcite/dolomite wathering, nor volcanic ash orgin, but may have originated, like a few of the stable elements, from rising hydrothermal solutions. (authors). 67 refs.; 8 figs.; 6 tabs

Preparation of Silver Nano-Particles and Use as a Material for Water Sterilization

Directory of Open Access Journals (Sweden)

Tran Hong Con

2011-01-01

Full Text Available High dispersed nanodimensional silver metal (nanosilver solution of concentration ranging from 40 to 400 mg/L was prepared from silver nitrate in water media with and without dispersing reagent. The reduction process was initiated by ammonium hydroxide and glucose was used as a reductive reagent. The nanosilver solution was characterized by color changing from light-yellow to yellow, brown, red-brown, brown-green, dark-green, blue, dark-blue and those were depending on silver concentration and dimension of silver metal particles. The nanosilver solution was possibly used as a direct sterilizing reagent or coating on calcinated laterite grains to create sterilizing material in bacterial removing filter. Direct sterilization ability of nanosilver solution and nanosilver coated material was investigated. The results showed that with 10 ppb nanosilver in supplied water, all bacteria will be removed within 25–30 min. 10 mm thick layer of silica gel or 20 mm of calcinated laterite coated nanosilver could remove all bacteria in water flowed though with maximum flow rate of 100 L.m2/min. Moreover, sterilizing material was nontoxic and applicable for drinking water production.

Influence of Curing Age and Mix Composition on Compressive Strength of Volcanic Ash Blended Cement Laterized Concrete

Directory of Open Access Journals (Sweden)

Babafemi A.J.

2012-01-01

Full Text Available This study investigates the influence of curing age and mix proportions on the compressive strength of volcanic ash (VA blended cement laterized concrete. A total of 288 cubes of 100mm dimensions were cast and cured in water for 3, 7, 28, 56, 90 and 120 days of hydration with cement replacement by VA and sand replacement by laterite both ranging from 0 to 30% respectively while a control mix of 28-day target strength of 25N/mm2 (using British Method was adopted. The results show that the compressive strength of the VA-blended cement laterized concrete increased with the increase in curing age but decreased as the VA and laterite (LAT contents increased. The optimum replacement level was 20%LAT/20%VA. At this level the compressive strength increased with curing age at a decreasing rate beyond 28 days. The target compressive strength of 25N/mm2 was achieved for this mixture at 90 days of curing. VA content and curing age was noted to have significant effect (α ≤ 0.5 on the compressive strength of the VA-blended cement laterized concrete.

Mineralogical and technology characterization of raw materials of clay used for ceramic blocks fabrication

International Nuclear Information System (INIS)

Campos, N.Q.; Tapajos, N.S.

2012-01-01

In the state of Para, the red ceramic industry has several segments highly generators of jobs and a strong social appeal. With so many companies focused on this productive sector emerge, but many without any administration quality. Therefore, this study focused the technological and mineralogical characterization of the raw material used in the manufacture of ceramic blocks, by Ceramica Vermelha Company, located in the district of Inhangapi-PA. The raw material was obtained by the techniques of X-ray diffraction (XRD) to determine the present crystalline phases through an accurate and efficient procedure, where it was possible to identify the peaks relating to montmorillonite, illite and kaolinite clay in the sample, and kaolinite and quartz in the sample laterite. Another important result was the absorption of water, with average satisfactory according to the standards. According to a sieve analysis, the laterite the sand fraction showed a greater extent compared to the other, while the clay silt exceeding 80% was found to be too plastic material. The resistance to compression, the results were below the required by the standard, suggesting more accurate test methods. (author)

Isotopic tracer studies to evaluate relative efficiency of different forms of P for growing rice on different soil types

International Nuclear Information System (INIS)

Dash, R.N.; Mohanty, S.K.; Patnaik, S.

1977-01-01

The relative efficiency of different forms of P in relation to their time of application for growing rice on different soil types has been studied by using 32 P tagged mono-, di-, and tri-calcium phosphate, ammonium nitrate phosphate containing all the P in the citrate-soluble form and potassium meta-phosphate. P-deficient acid laterite soil from Burdwan, red loam soil from Peramanpur and calcareous black soil from Hyderabad were used in the study. The different P forms were found to be compatible in the acid, red and laterite soils when the phosphorus forms were primed to moist acid soils 2 weeks prior to flooding. On application at flooding, fertilizers containing citrate-soluble phosphate were found to be less effective as compared to those containing water-soluble phosphate. In the calcareous black soil, however, the fertilizers, containing insoluble or citrate-soluble phosphates were not as efficient as the water-soluble forms, possibly because of lack of dissolution process. Potassium meta-phosphate was found to be effective in all the soil types whether applied at flooding or primed to the moist soil. (M.G.B.)

Determination of noble metals in geological materials by radiochemical neutron-activation analysis

International Nuclear Information System (INIS)

Ahmad, I.; Ahmad, S.; Morris, D.F.C.

1977-01-01

A method for the determination of platinum, palladium, gold and iridium in geological materials following activation with thermal neutrons is described. Radionuclides formed from the elements are separated by a scheme based largely on liquid-liquid extractions. The procedure has been applied to the analysis of US Geological Survey standard rocks and to studies of the distribution of the noble metals in lateritic nickel ores. (author)

Hydro Geo-Electrical Investigation in Gombe Town and Environs ...

African Journals Online (AJOL)

The sandy clay and sandstone constitute the aquifer zones with resistivity range of 28 ohm-m to 84 ohm-m for clay, 240 ohm-m to 501 ohm-m for sandstone, 967 ohm-m to 1008 ohm-m for sandy clay. Others are 2069 ohm-m to 9607 ohm-m for the calcareous and the laterite units and 17456 0hm-m for the compacted sands.

Gold grade variation and particle microchemistry in exploration pits of the Batouri gold district, SE Cameroon

Science.gov (United States)

Vishiti, A.; Suh, C. E.; Lehmann, B.; Egbe, J. A.; Shemang, E. M.

2015-11-01

The Batouri area hosts lode-gold mineralization under several-m-thick lateritic cover. Pitting to bed rock on a geochemical Au anomaly defined from previous reconnaissance soil sampling identified five horizons ranging from saprock at the base to laterite at the top. Analysis of bulk samples from each horizon by fire assay shows that most of the horizons are barren although 119 ppb and 48 ppb Au values were obtained from one laterite horizon and one saprolite horizon, respectively, from two separate pits. All the horizons were panned and particulate gold was also recovered only from these two horizons. The gold grains from both horizons are morphologically and compositionally indistinguishable with rare quartz, pyrite and galena inclusions. The grains have irregular, sub-rounded, bean to elongated shapes and they show a remarkable core-rim zonation. Electron microprobe analysis of the grains recorded high gold content in the rims (86.3-100 wt%) and along fissures within the grains (95.1-100 wt%). The cores are relatively Ag rich (11.8-14 wt% Ag) while the rims (0.63-13.7 wt% Ag, most of the values fall within the lower limit of this range) and fissures (0.03-5.02 wt% Ag) are poor in Ag. The low Ag concentration in the rims and along fissures is attributed to preferential leaching of Ag; a process recognized in gold grains and platiniferous alloys from alluvia. The core composition of the grains is similar to that of primary gold composition in the bedrock. These results show that gold in the soil is relic particulate gold derived from the primary source with no evidence of secondary gold precipitation in the weathering cycle. In all the pits no horizon was systematically enriched in gold suggesting there has been no chemical remobilization of gold in this environment. Rather the dispersion of gold here is in the particulate form. Therefore combining particulate gold features with assay data is relevant to exploration in such tropical environments.

Mineral resources of parts of the Departments of Antioquia and Caldas, Zone II, Colombia

Science.gov (United States)

Hall, R.B.; Feininger, Tomas; Barrero, L.; Dario, Rico H.; ,; Alvarez, A.

1970-01-01

The mineral resources of an area of 40,000 sq km, principally in the Department of Antioquia, but including small parts of the Departments of Caldas, C6rdoba, Risaralda, and Tolima, were investigated during the period 1964-68. The area is designated Zone II by the Colombian Inventario Minero Nacional(lMN). The geology of approximately 45 percent of this area, or 18,000 sq km, has been mapped by IMN. Zone II has been a gold producer for centuries, and still produces 75 percent of Colombia's gold. Silver is recovered as a byproduct. Ferruginous laterites have been investigated as potential sources of iron ore but are not commercially exploitable. Nickeliferous laterite on serpentinite near Ure in the extreme northwest corner of the Zone is potentially exploitable, although less promising than similar laterites at Cerro Matoso, north of the Zone boundary. Known deposits of mercury, chromium, manganese, and copper are small and have limited economic potentia1. Cement raw materials are important among nonmetallic resources, and four companies are engaged in the manufacture of portland cement. The eastern half of Zone II contains large carbonate rock reserves, but poor accessibility is a handicap to greater development at present. Dolomite near Amalfi is quarried for the glass-making and other industries. Clay saprolite is abundant and widely used in making brick and tiles in backyard kilns. Kaolin of good quality near La Union is used by the ceramic industry. Subbituminous coal beds of Tertiary are an important resource in the western part of the zone and have good potential for greater development. Aggregate materials for construction are varied and abundant. Deposits of sodic feldspar, talc, decorative stone, and silica are exploited on a small scale. Chrysotils asbestos deposits north of Campamento are being developed to supply fiber for Colombia's thriving asbestos-cement industry, which is presently dependent upon imported fiber. Wollastonite and andalusite are

characterization of geotechnical properties of lateritic soil-bentonite

African Journals Online (AJOL)

2013-03-01

Mar 1, 2013 ... cilities should ensure minimum fluid flow through or into the repository ... were evaluated using the rigid wall permeameter un- der falling ... cell pressure [22]. 3. Results .... them to retain a portion of water (double layer water) that may ... water in the pore space. ... The effect of bentonite content on volumetric.

Groundwater exploitation in the Abakaliki metropolis (southeastern ...

African Journals Online (AJOL)

While the uppermost layer has an apparent resistivity value of range 240 to 1120 ohm-m and a thickness of range 1.0 to 1.2 m, and is interpreted as lateritic overburden. The 2nd to 5th layers have apparent resistivity values that range from of 25 to 1025 ohm-m, with depth that range from 0.8 to 25 m. The 6th layer has mean ...

Nickel production in Serbia-technological and environmental aspects

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Željko Kamberović

2014-12-01

Full Text Available Demand for nickel is constantly growing due to the versatility of its application, at the first place for stainless steel production. Ore reserves and possibility of nickel production of today’s Serbia and in neighboring countries were thoroughly investigated, and presented work is part of a wider project of sublimation of scientific and professional experience in the field of nickel extractive metallurgy on domestic raw materials. Presented research explores the possibility of high pressure sulfuric acid leaching of Serbian lateritic ores from localities Rudjinci, Ba and Lipovac. All three investigated ore deposits behaved differently both during preparation and during hydrometallurgical treatment. As optimal method for ore preparation proved to be crushing-milling-sieving route, but without possibility of concentrate production. Only for Rudjinci ore deposit achieved leaching efficiency reached satisfactory level of 95%. Within presented paper flow-sheet is proposed for processing high-magnesium laterite ores, with iron and magnesium oxide Both could be recirculated and used again in technological process; MgO for iron precipitation and SO2 for production of leaching agent, sulfuric acid. Final decision on the sustainability of the process will be made according to techno-economic and environmental evaluation. Estimated overall impact of the project implementation on the environment is negative.

Unravelling regolith material types using Mg/Al and K/Al plot to support field regolith identification in the savannah regions of NW Ghana, West Africa

Science.gov (United States)

Arhin, Emmanuel; Zango, Saeed M.

2015-12-01

The XRF analytical method was used to measure the weight % of the major oxides in regolith samples. The metal weight % of Mg, K and Al were calculated from their oxides and were normalised relative to immobile Al calculated from its oxide. The plot of Mg/Al and K/Al identified the regolith of the study area to consist of 137 transported clays, 4 ferruginous sediments or ferricrete, 2 lateritic duricrust and 4 saprolites. Surface regolith that had undergone secondary transformation and shows compositional overlaps were 4 transported clays with Fe-oxide impregnation may be referred to as nodular laterite and 5 ferruginous saprolites. The variable regolith materials features identified from the 154 samples enabled the characterisation and identification of the different sample materials because an overprint of bedrock geochemistry is reflected in the regolith. Plot of Mg/Al and K/Al highlighted the compositional variability of the regolith samples and refute the notion of the homogeneity of all the sampled materials in the area. The study thus recognized Mg/Al versus K/Al plots to be used in supporting field identification of regolith mapping units particularly in complex regolith terrains of savannah regions of Ghana and in similar areas where geochemical exploration surveys are being carried out under cover.

Rehabilitating acid soils for increasing crop productivity through low-cost liming material.

Science.gov (United States)

Bhat, Javid Ahmad; Kundu, Manik Chandra; Hazra, Gora Chand; Santra, Gour Hari; Mandal, Biswapati

2010-09-15

Productivity of red and lateritic soils is low because of their acidity and deficiencies in few essential nutrients viz., nitrogen, phosphorus, calcium, zinc, boron, molybdenum etc. We compared the effectiveness of basic slag, a low-cost liming material, with that of calcite as an ameliorant for these soils using mustard followed by rice as test crops. Experiments were conducted with three levels of each of basic slag and calcite along with a control on farmers' fields at 14 different locations. Influence of farmyard manure (FYM) and poultry manure (PM) on the effectiveness of the slag was also tested. On an average, basic slag performed better than calcite in increasing yields of both mustard and rice and left over higher amounts of available Ca, Si and Zn in residual soils. The slag also improved N, P, K and Ca nutrition of mustard and Si and Zn nutrition of rice with a favorable benefit:cost (B:C) ratio over the calcite (4.82 vs. 1.44). Effectiveness of the basic slag improved when it was applied in combination with FYM or PM (B:C, 5.83 and 6.27). Basic slag can, therefore, be advocated for use in the acidic red and lateritic soils for economically improving their productivity. Copyright 2010 Elsevier B.V. All rights reserved.

Rehabilitating acid soils for increasing crop productivity through low-cost liming material

International Nuclear Information System (INIS)

Bhat, Javid Ahmad; Kundu, Manik Chandra; Hazra, Gora Chand; Santra, Gour Hari; Mandal, Biswapati

2010-01-01

Productivity of red and lateritic soils is low because of their acidity and deficiencies in few essential nutrients viz., nitrogen, phosphorus, calcium, zinc, boron, molybdenum etc. We compared the effectiveness of basic slag, a low-cost liming material, with that of calcite as an ameliorant for these soils using mustard followed by rice as test crops. Experiments were conducted with three levels of each of basic slag and calcite along with a control on farmers' fields at 14 different locations. Influence of farmyard manure (FYM) and poultry manure (PM) on the effectiveness of the slag was also tested. On an average, basic slag performed better than calcite in increasing yields of both mustard and rice and left over higher amounts of available Ca, Si and Zn in residual soils. The slag also improved N, P, K and Ca nutrition of mustard and Si and Zn nutrition of rice with a favorable benefit:cost (B:C) ratio over the calcite (4.82 vs. 1.44). Effectiveness of the basic slag improved when it was applied in combination with FYM or PM (B:C, 5.83 and 6.27). Basic slag can, therefore, be advocated for use in the acidic red and lateritic soils for economically improving their productivity.

Rehabilitating acid soils for increasing crop productivity through low-cost liming material

Energy Technology Data Exchange (ETDEWEB)

Bhat, Javid Ahmad [Directorate of Research, Bidhan Chandra Krishi Viswavidyalaya, Kalyani - 741 235, West Bengal (India); Kundu, Manik Chandra, E-mail: mckundu@rediffmail.com [Directorate of Research, Bidhan Chandra Krishi Viswavidyalaya, Kalyani - 741 235, West Bengal (India); Hazra, Gora Chand [Directorate of Research, Bidhan Chandra Krishi Viswavidyalaya, Kalyani - 741 235, West Bengal (India); Santra, Gour Hari [Department of Soil Science and Agril. Chemistry, Orissa University of Agriculture and Technology, Bhubaneswar - 751003, Orissa (India); Mandal, Biswapati [Directorate of Research, Bidhan Chandra Krishi Viswavidyalaya, Kalyani - 741 235, West Bengal (India)

2010-09-15

Productivity of red and lateritic soils is low because of their acidity and deficiencies in few essential nutrients viz., nitrogen, phosphorus, calcium, zinc, boron, molybdenum etc. We compared the effectiveness of basic slag, a low-cost liming material, with that of calcite as an ameliorant for these soils using mustard followed by rice as test crops. Experiments were conducted with three levels of each of basic slag and calcite along with a control on farmers' fields at 14 different locations. Influence of farmyard manure (FYM) and poultry manure (PM) on the effectiveness of the slag was also tested. On an average, basic slag performed better than calcite in increasing yields of both mustard and rice and left over higher amounts of available Ca, Si and Zn in residual soils. The slag also improved N, P, K and Ca nutrition of mustard and Si and Zn nutrition of rice with a favorable benefit:cost (B:C) ratio over the calcite (4.82 vs. 1.44). Effectiveness of the basic slag improved when it was applied in combination with FYM or PM (B:C, 5.83 and 6.27). Basic slag can, therefore, be advocated for use in the acidic red and lateritic soils for economically improving their productivity.

Adsorption and desorption behavior of herbicide diuron on various Chinese cultivated soils.

Science.gov (United States)

Liu, Yihua; Xu, Zhenzhen; Wu, Xiaoguang; Gui, Wenjun; Zhu, Guonian

2010-06-15

The adsorption-desorption behaviors of diuron were investigated in six cultivated soils of China. The effect of system pH and temperature were also studied. The data fitted the Freundlich equation very well. The adsorption K(F) values indicated the adsorption of diuron in the six soils was in the sequence of black soil (D)>yellow earth (F)>paddy soil (B)>yellow-brown soil (C)>yellow-cinnamon soil (A)>lateritic red earth (E). The adsorption K(F) and Freundlich exponents n were decreased when temperature was increased from 298 K to 318 K. However, the Gibb's free energy values were found less negative with the increasing temperature. Meanwhile, the extent of diuron adsorption on soil was at rather high level under low pH value conditions and decreased with increasing pH value. In addition, the desorption behavior of diuron in the six soils was in the sequence of lateritic red earth (E)>yellow-cinnamon soil (A)>paddy soil (B)>yellow earth (F)>yellow-brown soil (C)>black soil (D). At the same time, desorption hysteresis of diuron were observed in all of the tested soils. And the soil organic matter content may play an important role in the adsorption-desorption behavior. Copyright 2010 Elsevier B.V. All rights reserved.

Qualitative characterization by x-ray diffraction from soils: mineralogy conditions to benefit the environment

International Nuclear Information System (INIS)

Fujiyama, Bruna Sayuri; Tavares, Mauricio de Moraes

2010-01-01

Four samples were collected from four soil profiles located in the Rural Federal University of Amazonia. These, were analyzed parameters such as color, texture, consistency, granulometry, porosity and water absorption. We identified the following soil types: Distrofic Yellow Latosoil; Lateritic Concretionary; distrofic Low Humic Gley. The work was to continue the qualitative analysis by X-rays diffraction, identifying the mineralogical composition of each sample. Explaining the mineralogical conditions that affect or benefit the environment. (author)

Adaptação de métodos semi-empíricos para estimar capacidade de carga de estacas de pequeno diâmetro no solo de Londrina, Estado do Paraná = Adaptation of the semi-empiric methods to calculate small diameter piles bearing capacity in the soil of Londrina City, Paraná State

Directory of Open Access Journals (Sweden)

Miriam Gonçalves Miguel

2005-07-01

Full Text Available A cidade de Londrina, Estado do Paraná, possui um perfil geotécnicoconstituído de uma camada superficial de solo argilo-siltoso, poroso, laterítico e muitas vezes colapsível, que se estende até a profundidade máxima de 12 metros. As estacas utilizadas em obras de pequeno a médio porte se encontram totalmente embutidas nesta camada, sofrendo a influência de seu comportamento laterítico e colapsível. Os métodos clássicos brasileiros de estimativa de capacidade de carga de estacas tornam-se conservadores, frente aos resultados reais, quando aplicados em solos lateríticos e, contra a segurança, quando aplicados em solos colapsíveis, isto é, na condição crítica ao colapso. Este trabalho avalia os coeficientes de ajuste das resistências de ponta e ao atrito lateral para esses métodos, no caso de estacas apiloadas, sendo estes coeficientes obtidos pela retro-análise de resultados de provas de carga estática à compressão, realizadas no Campo Experimental de Engenharia Geotécnica da Universidade Estadual de Londrina.The city of Londrina, Paraná, has a typical geotechnical profile defined by a superficial layer of porous silty clay with maximum depth of about 12 meters, that shows lateritic characteristics, andmany times, collapsibility. Casts in place piles are often used for small buildings in the region and are fully embedded in this soil layer. Therefore, this type of foundation is subjected to the lateritic and occasionally collapsible influence of soil. Brazilian pile bearing capacity methods may yield conservative results when applied to tropical soils, as far as the lateritic origin in concerned. On the other hand, it can be unsafe if collapsibility prevails. This paper evaluates coefficients to adjust both point and lateral resistance of cast in place small diameter piles in the situation described. The work was carried out at the Londrina State University Geotechnical Experimental Site, and back analysis from static

Green and sustainable median on a divided multilane highway

Science.gov (United States)

Ambak, K.; Bajuri, F. A. A.; Yusoff, N. A.; Madun, A.; Prasetijo, J.

2017-11-01

The road system in Malaysia showed good growth with increasing number of vehicles on the road. However, statistic of road accident is still at an alarming rate. There are many factor can contribute to the occurrence of an accident. If the accident was caused by road facilities such as street furniture, it is shown that the street furniture was failed to improve the safety of the road users. In this study, a new concept of materials for the construction of road dividers was purpose. The sustainable materials such as laterite soil, Cow Grass, tires and PVC pipes was used to replace the cement and iron guardrails in road divider construction. The main objectives of this study is to design characteristics of a road divider using natural material such as laterite soil, sand, grass and recycle material like used a tyre. A series of experiments such as test liquid limit, plastic limit test, standard proctor test and observations of root growth in 30 days were conducted. The result shows that the plastic index value of 35% was obtained. From the proctor compaction test, the optimum water content was 23% and maximum dry density at 15.3 kN/m3. This value was used to build a prototype of green and sustainable raised road median. The suitability of sand used as the medium in irrigation system was approved. Permeability of sand is 10-2 mm/s to 10 mm/s which is having a high rate of flow. The growth of Cow Grass roots was increased by 4.9 cm in 30 days. This shows that, the grass is suitable to grow in laterite soil and can be used as vegetation material. Through the impact test conducted on a model with a scale of 1:7.5, indicate the initial damage occurred when a force reaches 10N. However, the condition of the model is still stable. From the impact test conducted, the prototype of green and sustainable raised road median has a good potential to be used as existing road divider as it can absorb the impact of an accident.

Long-term temporal variability of the radon-222 exhalation flux from a landform covered by low uranium grade waste rock

International Nuclear Information System (INIS)

Bollhöfer, Andreas; Doering, Che

2016-01-01

Radon-222 exhalation flux densities from two different substrates of several metres thickness, waste rock and waste rock mixed with approximately 30% lateritic material, were measured over a period of five years in the wet-dry tropics of Northern Australia. Fourteen measurement campaigns using activated charcoal canisters (n > 1000) covered both dry and wet seasons and showed differences in seasonal and long term trends of the "2"2"2Rn exhalation flux densities normalised to the "2"2"6Ra activity concentrations of the substrate. Dry season "2"2"2Rn exhalation was generally higher for the mixed substrate, due to the larger fraction of fines. Seasonality established within the first year of landform construction on the mixed substrate, due to the higher water holding capacity of the lateritic material. In contrast, waste rock only shows no seasonality until years four and five after construction, when average normalised dry season "2"2"2Rn exhalation flux densities from waste rock increase to values (0.47 ± 0.06 mBq m"−"2 s"−"1 per Bq kg"−"1) similar to the mixed substrate (0.64 ± 0.08 mBq m"−"2 s"−"1 per Bq kg"−"1), likely due to an increase in fines from rapid weathering of the schistose waste rock. Volumetric water content has been used to parametrize relative "2"2"2Rn exhalation and we determined that wet season "2"2"2Rn exhalation is about 40% of the dry season exhalation. - Highlights: • We determined "2"2"2Rn exhalation flux densities normalised to "2"2"6Ra activity concentrations (R_E_-_R) for two substrates. • R_E_-_R was lower for waste rock only compared to waste rock blended with 30% fine grained lateritic material. • Seasonality in waste rock "2"2"2Rn exhalation flux densities established 4 years after construction. • Wet season R_E_-_R was about 40% of the dry season R_E_-_R.

Seasonal variability of beach characteristics between Candoliam and Colva coast, Goa, India.

Digital Repository Service at National Institute of Oceanography (India)

Wilson, J.S.J.; Sujitha, S.B.; Shruti, V.C.; Shaeema, Z.A.; PrasannaKumar, S.; Chandrasekar, N.

and Aguada promontory and in the south by Cabo-da-Gama promontory, 3 locations were chosen to understand the temporal variability of beach morphology. 2.1. Physiography Physiographically, Goa can be broadly divided onto four distinct morphological.... Structural features like lineament, inselbergs, laterite mesas are also noticed in the study area. Near- shore morphological features like Shore Island and salt marsh are also seen around the study area. Fig. 1 Location map of the study area 35 3...

Assessment of bauxite, clay, and laterite deposits in Afghanistan

Science.gov (United States)

Renaud, Karine M.; Wardlaw, Bruce R.; Hubbard, Bernard E.

2015-01-01

Bauxite-bearing rocks are present in several regions of Afghanistan; specifically, the southeast segment of the North Afghanistan Platform, the eastern parts of South Afghanistan, and within the Afghanistan-North and -South Pamir Fold Regions. Bauxite-bearing rocks occur at various stratigraphic levels, in lithologically different sequences of sedimentary rocks. The bauxites are paleosols and represent previous, rather than recent, weathering events. Bauxites and bauxite-type horizons are most common at the base of carbonate rock units, where they form the basal horizons of sedimentary rock sequences separated by erosion and stratigraphic unconformity surfaces. Less common are zones in redeposited weathering developed on igneous rocks. At present there are five known stratigraphic intervals with significant bauxite and bauxite-type deposits and occurrences: the lower Permian, the upper Permian, the Upper Triassic, the Lower Jurassic, and the base of the Upper Jurassic.

characterization of terrain and biotite gneiss-derived lateritic soils

African Journals Online (AJOL)

DJFLEX

2010-04-08

Apr 8, 2010 ... from 23m above mean sea level in the lowlying areas to. 41m (msl) for the high rise area is decorated on the eastern part with Inselbergs of ..... through landfill liners Florida centre for solid and hazardous waste management ...

compaction delay versus properties of cement-bound lateritic soil

African Journals Online (AJOL)

hp

hour intervals on soil-cement mixes 3,5,8; and 1, 3, 5 percent cement contents by weight of dry soils, for ... stabilized soils were the Compaction test (Standard Proctor), the Unconfined Compressive. Strength .... Plastic limit (%). % passing BS ...

Multivariate erosion risk assessment of lateritic badlands of Birbhum ...

Indian Academy of Sciences (India)

Erosion risk; soil erosion; sediment yield; multivariate analysis; GIS. J. Earth Syst. Sci. 121, No. ... ers are threatened by excessive soil loss by water. To reach that goal the ... nacle erosion, bare soil cover, barren waste land, tunnels and ...

ERT and Well Data Tie for Nickel Laterite Characterization

Science.gov (United States)

Aswad, Sabrianto; Mamela Mais, Difar; Syamsuddin; Wanni

2018-03-01

The need of ERT method in nickel latentes exploration can’t be deny. This method have capability to make exploration more effective and efficient. In reality this method still remain ambiguity in its application, especially for geologist and mining expert. These ambiguity related with layer zone determination (limonite, saprolite and bedrock), the same resistivity values in the different zones and determination of bedrock. This paper try to expose interesting fact to overcome this ambiguity by using ERT data and drill data tie. This tie will show characteristic of nickel lateric based on resisitivity value and the contribution of chemistry element for resistivity value. Data ERT was collected by using gradient configuration and well data consist of mayor element and minor element. Tie result showed difference resistivity value in limonite layer influence by Fe, H2O and Ni, where resistivity value from saprolite layer influenced by Fe, H2O, Si02, MgO, Al, Cr, and Ni in certain accumulation. In bedrock layer, almost all drill data did not reach bedrock but only reached the boulder alone, it is supported by the value of the resistivity of rock unserpentinized peridotite which should show a relatively large resistivity value

Response of Haloalkaliphilic Archaeon Natronococcus Jeotgali RR17 to Hypergravity

Science.gov (United States)

Thombre, Rebecca S.; Bhalerao, Aniruddha R.; Shinde, Vinaya D.; Dhar, Sunil Kumar; Shouche, Yogesh S.

2017-06-01

The survival of archaeabacteria in extreme inhabitable environments on earth that challenge organismic survival is ubiquitously known. However, the studies related to the effect of hypergravity on the growth and proliferation of archaea are unprecedented. The survival of organisms in hypergravity and rocks in addition to resistance to cosmic radiations, pressure and other extremities is imperative to study the possibilities of microbial travel between planets and endurance in hyperaccelerative forces faced during ejection of rocks from planets. The current investigation highlights the growth of an extremophilic archaeon isolated from a rocky substrate in hypergravity environment. The haloalkaliphilic archaeon, Natronococcus jeotgali RR17 was isolated from an Indian laterite rock, submerged in the Arabian sea lining Coastal Maharashtra, India. The endolithic haloarchaeon was subjected to hypergravity from 56 - 893 X gusing acceleration generated by centrifugal rotation. The cells of N. jeotgali RR17 proliferated and demonstrated good growth in hypergravity (223 X g). This is the first report on isolation of endolithic haloarchaeon N. jeotgali RR17 from an Indian laterite rock and its ability to proliferate in hypergravity. The present study demonstrates the ability of microbial life to survive and proliferate in hypergravity. Thus the inability of organismic growth in hypergravity may no longer be a limitation for astrobiology studies related to habitability of substellar objects, brown dwarfs and other planetary bodies in the universe besides planet earth.

Clay minerals and Sr-Nd isotopes of the sediments along the western margin of India and their implication for sediment provenance

Digital Repository Service at National Institute of Oceanography (India)

Kessarkar, P.M.; Rao, V.P.; Ahmad, S; Babu, G.A.

- gion is occupied by Recent alluvium and the Warkala beds (ferruginised sand stones with inter- calated clays) of Tertiary age. Extensive laterisation of the parent rocks is a characteristic feature in western India. Bauxite- and laterite...^Nd isotopes of the sediments along the western margin of India and their implication for sediment provenance Pratima M. Kessarkar a , V. Purnachandra Rao a;C3 , S.M. Ahmad b , G. Anil Babu b a National Institute of Oceanography, Dona Paula, Goa 403 004, India...

Iron ore pollution in Mandovi and Zuari estuarine sediments and its fate after mining ban

Digital Repository Service at National Institute of Oceanography (India)

Kessarkar, P.M.; Suja, S.; Sudheesh, V.; Srivastava, S.; Rao, V.P.

). Another possibility could be formation of ferritized iron crust (Mathe et al. 1997) during lateritic weathering. Magnetic properties of upstream sediments of Ma-Zu estuaries Sediments from the upstream of Mandovi (M6-M9) and Zuari (Z6-Z9) estuaries... for late Quaternary climatic change. Marine Geology, 220, 59-82. Maher, B. A., & Taylor, R. M. (1988). Formation of ultrafine-grained magnetite in soils. Nature, 336, 368-370. Mathe, P. E., Rochette, P., & Colin, F. (1997). The origin of magnetic...

Arid processes in the SE-Brazilian relief evolution during the last glacial

International Nuclear Information System (INIS)

Lichte, M.

1991-01-01

The general index-plain Sulamericana can be found in vast areas of SE-Brazil. It is mainly conserved with the help of a duricrust and covered by laterite. The next younger element of relief-evolution, a level 40 to 60 m below the Sulamericana, is completely different: the weathered rock is covered by a stone line and a fine-textured sediment. This structure was examined with the help of granulometry, analyses of heavy minerals, thermoluminescence datings, pollen analyses and 14 C-datings. (author)

Surficial clay mineral distribution on the southwestern continental margin of India: Evidence of input from the Bay of Bengal

Digital Repository Service at National Institute of Oceanography (India)

Chauhan, O.S.; Gujar, A.R.

LATERITE 3922 MIOCENE SANDSTONE (~) ARCHEANS ( GRANITE GNEISS I' --J CHARNOKITES ~ KHONOALITES) ~J 3940 -t- -4- -t- -t- ~ .. t Jr -4- + + + + Jr -t- Jr + Jr -t- -t- 4- -t- 4- Jre" + -t- + 4- + -t-.. + + 4- WADGE BANK INDIA -~ + + + + *4 t... et al., 1990). In the southern region, the shelf is marked by a low gradient physiographic feature, i.e. Wadge Bank (gradient 1:756), which has considerably enhanced the width of the shelf. The shelf break is shallowest in this region...

Lichens of the Mahabaleshwar Panchgani Ecosensitive zone (MPESZ, Maharashtra, India

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G.S. Pandit

2014-05-01

Full Text Available Mahabaleshwar Panchgani Ecosensitive Zone located in the Northern Western Ghats of India is well known for its rich biodiversity. Rocky plateaus of laterite are a prominent feature of this region along with a mosaic landscape of forest and shrub-savannah vegetation. A checklist of 129 lichen species reported from this region has been compiled based upon primary and secondary data. They are categorized as per forms and substrates. The need for further studies and protection of this rich lichen diversity is emphasized.

Nest architecture of Oxaea austera (Andrenidae, Oxaeinae and its significance for the interpretation of Uruguayan fossil bee cells

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Laura Sarzetti

2014-09-01

Full Text Available Oxaea austera nests in hard, red lateritic soils with dense grass cover. Some characters of Oxaea austera nests conform to the known architecture of the oxaeine nests such as the long, vertical shaft and the radiating, horizontal tunnels connected to vertical cells. The presence of more than one cell per lateral, cells at different depths containing larvae at different stages, and discrete walls in the main and laterals are described for the first time for Oxaeinae. One cell was located at the end of each lateral with others (2–4 near them, in some cases arranged in a row just beneath the lateral. Cells are oriented vertically and consist of a chamber, a spiral closure and an antechamber connected with a lateral. The chamber and antechamber are surrounded by a thick discrete wall. Each nest was occupied by at least two active females indicating communal nesting. They also contained older cells, suggesting the reutilization of the nests by successive generations. Both behaviors may be a response to the difficulties of excavation in hard soils. Communal nesting may be also a defensive behavior against nest cleptoparasites. The shape, size, discrete walls of lateritic soil material, spiral closure, and antechamber of O. austera cells closely resemble the fossil bee cells included in the ichnogenus Palmiraichnus from the early Eocene Asencio Formation of Uruguay. This new evidence reinforces the proposal of extinct representatives of Oxaeinae as it constructor.

Metal recovery via geobiotechnology

International Nuclear Information System (INIS)

Hedrich, Sabrina; Schippers, Axel

2017-01-01

Specialized acidophilic bacteria and archaea are able to extract valuable metals such as copper, gold, cobalt, nickel, zinc, and uranium from sulfide ores. This process is known as bioleaching and its application in the mining industry as biomining. Laboratory studies also demonstrated bioleaching of oxide ores such as laterites and of mining residues such as mine tailings as well as metal recycling from waste (secondary mining). Metals being leached have to be recovered from acidic polymetallic solutions (mine and process waters) which is possible via biosorption or biomineralisation.

Metal recovery via geobiotechnology; Metallgewinnung mittels Geobiotechnologie

Energy Technology Data Exchange (ETDEWEB)

Hedrich, Sabrina; Schippers, Axel [Bundesanstalt fuer Geowissenschaften und Rohstoffe (BGR), Hannover (Germany). Fachbereich Geochemie der Rohstoffe

2017-02-15

Specialized acidophilic bacteria and archaea are able to extract valuable metals such as copper, gold, cobalt, nickel, zinc, and uranium from sulfide ores. This process is known as bioleaching and its application in the mining industry as biomining. Laboratory studies also demonstrated bioleaching of oxide ores such as laterites and of mining residues such as mine tailings as well as metal recycling from waste (secondary mining). Metals being leached have to be recovered from acidic polymetallic solutions (mine and process waters) which is possible via biosorption or biomineralisation.

Sapling growth of Eucalyptus tereticornis under various edapho-climatic regions of Tamil Nadu

Energy Technology Data Exchange (ETDEWEB)

Krishnaswami, S; Rai, R S.V.; Srinivasan, V M

1982-01-01

Girth at b.h. (o.b.) was measured in 2-4 yr old plantations at 6 sites on various soil types with annual rainfalls of 70-100 cm. Best average growth at 2x2-m spacing (over 29 cm girth at 4 yr old) was on sandy river banks with 90 cm rainfall and the worst (20-21 cm at 4 yr old) on poor gravelly and lateritic soils with low rainfall. It is suggested that strains should be selected to suit different local soil and climatic conditions. (Refs. 8).

Chromium stable isotope fractionation in modern biogeochemical cycling

DEFF Research Database (Denmark)

Paulukat, Cora Stefanie

oxygen in the Earth’s atmosphere. Oxidative rock weathering on land induces oxidation of immobile Cr(III) to mobile Cr(VI). Isotopically relatively heavy Cr(VI) is released to runoff, and transported by rivers to the oceans, where it is incorporated into chemical sediments and carbonate shells...... laterite soils from India, formed on ultramafic rocks, indicates extensive leaching of isotopically heavy Cr(VI). Transferring this knowledge to ancient weathering profiles, negatively fractionated Cr is clear evidence for the presence of free oxygen in the atmosphere. The second part demonstrates...

Influence of Stockpile Angle in Natural Drying of Laterite Ore

Directory of Open Access Journals (Sweden)

Yoalbys Retirado-Mediaceja

2016-10-01

Full Text Available Natural drying is performed at Cuban nickel plants by depositing bulk ore in the open. The ore is currently being stockpiled without much consideration for the impact of the drying surface angle on the process power behavior. Simulations were carried out in this investigation, which prove that an increased triangular stockpile angle considerably reduces natural drying efficiency. A 45 sexagesimal degree angle to the horizontal plane results in exposure of a large volume of ore to natural drying and guarantees adequate energy performance.

Fluoride adsorption onto an acid treated lateritic mineral from Kenya ...

African Journals Online (AJOL)

1) from Kenya was studied by batch experiments. The effect of acid-treatment of adsorbent and change in temperature, mass of LM-1, pH and selected competing ions was evaluated. The adsorption process was strongly influenced by ...

Fluoride adsorption onto an acid treated lateritic mineral from Kenya ...

African Journals Online (AJOL)

Wambu

adsorption on commercial activated carbons and alumina. (Chaturvedi et al., 1990), ion-exchange ... chemical composition showed that the adsorbent had a ..... fixed bed packed with granular calcite Water Res., 33: 3395–3402. Onyango MS ...

Effects of Periwinkle Shell Ash on Lime-Stabilized Lateritic Soil ...

African Journals Online (AJOL)

Journal of Applied Sciences and Environmental Management. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 21, No 6 (2017) >. Log in or Register to get access to full text downloads.

Mineralogy, geochemistry, and palynology of modern and late Tertiary mangrove deposits in the Barreiras Formation of Mosqueiro Island, northeastern Pará state, eastern Amazonia

Science.gov (United States)

Behling, Hermann; da Costa, Marcondes Lima

2004-12-01

A coastal environment has been interpreted from 110 cm thick mudstone deposits found at the base of a 10 m immature laterite profile, which forms the modern coastal cliff on Mosqueiro Island in northeastern Pará state, northern Brazil. The late Tertiary sediment deposits of the Barreiras Formation are studied by multi-element geochemistry and pollen analyses. The mineralogical and geochemical results show that the gray, organic-rich deposits are composed of kaolinite, quartz, and illite/muscovite, as well as pyrite and anatase. They are rich in SiO 2, Al 2O 3, and some FeO. The composition is homogenous, indicating that the detritus source area is formed of lateritic soils derived from acid rock composition. Their chemical composition, including trace elements, is somewhat comparable to continental shale, and the values are below the upper continental Earth crust composition. The pollen analytical data document that the mudstone deposits were formed by an ancient mangrove ecosystem. Mineralogical, geochemical, and pollen analytical data obtained from late Tertiary mangrove deposits are compared with modern mangrove deposits from the Bragança Peninsula of the northeastern coast of Pará state. Although the pollen composition of the deposits is very similar to the modern one, the geochemical and mineralogical composition is different. Smectite was only found in the modern deposit; illite/mica occurs in the ancient deposit, along with Mg, K, and Na. The pollen signature and detrital minerals (kaolinite, quartz and anatase) found in both mangrove deposits show that during the Miocene, a humid tropical climate condition prevailed, similar to modern conditions.

The fate of chromium during tropical weathering

DEFF Research Database (Denmark)

Berger, Alfons; Frei, Robert

2014-01-01

We performed a mineral, geochemical and Cr–Sr–Pb isotope study on a laterite profile developed on ca. 540 Ma old tonalitic bedrock in Madagascar with special emphasis on the behavior of chromium during tropical weathering. The observed strong depletions of Ca, Si, and P, and enrichment of Fe and Al...... of a former, positively fractionated and mobile chromium pool has been experimentally constrained in circumneutral and basic leachates of powdered tonalite bedrock where δ53Cr of + 0.21 to + 0.48‰ was measured. Our results show that mobilization of chromium is effective under highly oxidative conditions...

Analysis of nickel industrial wastes by nuclear techniques and its pollution assessment

International Nuclear Information System (INIS)

Diaz Rizo, O.; Coto Hernandez, I.; Lopez Pino, N.; D'Alessandro Rodriguez, K.; Arado Lopez, J.O.; Diaz Arado, O.; Reyes Perez, H.

2011-01-01

The concentration of some heavy metal (Mn, Fe, Co, Ni, Cu and Zn) in nickel industrial wastes from Moa, northeastern Cuba, is determined. The analysis was performed by External Standard method of ED-XRF, using 238 Pu (1.11 GBq) excitation source and laterite certified reference material as standards. The capability of INAA using neutrons from a Pu-Be (10 7 n/s) source and Low-Background Gamma Spectrometer (LBGS) at InSTEC is studied. The determined concentration values for Ni, Co, Cu and Zn shows a different pollution degree according to Dutch regulations and US NOAA guidelines. (Author)

Occurrence model for magmatic sulfide-rich nickel-copper-(platinum-group element) deposits related to mafic and ultramafic dike-sill complexes: Chapter I in Mineral deposit models for resource assessment

Science.gov (United States)

Schulz, Klaus J.; Woodruff, Laurel G.; Nicholson, Suzanne W.; Seal, Robert R.; Piatak, Nadine M.; Chandler, Val W.; Mars, John L.

2014-01-01

Magmatic sulfide deposits containing nickel (Ni) and copper (Cu), with or without (±) platinum-group elements (PGE), account for approximately 60 percent of the world’s nickel production. Most of the remainder of the Ni production is derived from lateritic deposits, which form by weathering of ultramafic rocks in humid tropical conditions. Magmatic Ni-Cu±PGE sulfide deposits are spatially and genetically related to bodies of mafic and/or ultramafic rocks. The sulfide deposits form when the mantle-derived mafic and/or ultramafic magmas become sulfide-saturated and segregate immiscible sulfide liquid, commonly following interaction with continental crustal rocks.

soil loss estimation through usle and mmf methods in the lateritic

African Journals Online (AJOL)

Osondu

relative comparison and suitability of both methods in the precise estimation of ... district, West Bengal and eastern Shikaripara ... the cartographic works, ranging from ... crop cover management factor; combines the C and P factors of USLE.

soil loss estimation through usle and mmf methods in the lateritic

African Journals Online (AJOL)

Osondu

soil moisture content at field capacity (wt%). BD bulk density of the ... slope steepness (o). A proportion (between 0 and 1) of the rainfall intercepted by the ... H = annual rate of soil particle detachment by runoff (Kg m-2). J = annual rate of total ...

Utilization of Agricultural Wastes in Stabilization of Landfill Soil

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Nidzam Rahmat Mohamad

2014-01-01

Full Text Available Palm Oil Fuel Ash (POFA and Rice Husk Ash (RHA are local agricultural waste material from Palm Oil Industry and from Paddy Industry in Malaysia. Currently, the disposal of these ashes from a burning process is a problem to both industries, and hence leads to environmental pollution. The main aim of this research was to investigate the potential of utilizing POFA and RHA as sustainable stabilizer material as partial replacement of traditional one which is lime and Portland Cement (PC. Laboratory investigations were carried out to establish the potential utilization of Malaysian Agricultural wastes POFA and RHA in stabilizing Teluk Kapas Landfill soil. Landfill soil on its own and combination with laterite clay soil were stabilized using POFA or RHA either on its own or in combination with Lime or Portland Cement (PC. The traditional stabilizers of lime or Portland Cement (PC were used as controls. Compacted cylinder test specimens were made at typical stabilizer contents and moist cured for up to 60 days prior to testing for compressive and water absorption tests. The results obtained showed that landfill soil combined with laterite clay (50:50 stabilized with 20% RHA:PC (50:50and POFA: PC (50:50 recorded the highest values of compressive strength compared to the other compositions of stabilizers and soils. However, when the amount of POFA and RHA increased in the system the compressive strength values of the samples tends to increase. These results suggest technological, economic as well as environmental advantages of using POFA and RHA and similar industrial by-products to achieve sustainable infrastructure development with near zero industrial waste.

Mineralogy, petrology and geochemistry of the Pocos de Caldas analogue study sites, Minas Gerais, Brazil

International Nuclear Information System (INIS)

Waber, M.

1991-01-01

The thorium-rare-earth element deposit at Morro do Ferro is of supergene origin and was formed under lateritic weathering conditions. The ore body forms shallow NW-SE elongated argillaceous lenses that extend from the top of the hill downwards along its south-eastern slope. The deposit is capped by a stockwork of magnetite veins which have protected the underlying, highly argillaceous host rock from excessive erosion. The surrounding country rocks comprise a sequence of subvolcanic phonolite intrusions that have been strongly altered by hydrothermal and supergene processes. From petrological, mineralogical and geochemical studies and mass balance calculations, it is inferred that the highly weathered host rock was originally carbonatic in composition and was initially enhanced in thorium and rare-earth elements compared to the surrounding silicate rocks. Intrusion of the carbonatite produced fenitic alteration of the surrounding phonolites, consisting of an early potassic alteration followed by a vein-type Th-REE mineralization with associated fluorite, carbonate, pyrite and zircon. Subsequent lateritic weathering has completely destroyed the carbonatite, forming a residual supergene enrichment of Th and REEs. Initial weathering of the carbonatite leading to solutions enriched in carbonate and phosphate may have appreciably restricted the dissolution of the primary Th-REE phases. Strongly oxidic weathering has resulted in a fractionation between cerium and the other light rare-earth elements. Ce 3+ is oxidized to Ce 4+ and retained together with thorium by secondary mineral formation and adsorption on poorly crystalline iron- and aluminium-hydroxides. In contrast, the trivalent LREEs are retained to a lesser degree and are thus more available for secondary mineral formation and adsorption at greater depths down the weathering column. (author) figs., tabs., 60 refs

Geology, mineralogy, geochemistry and origin of phosphates from Jandia, Cansa Perna, Itacupim (Para) and Pirocaua and Trauira (Maranhao)

International Nuclear Information System (INIS)

Costa, M. L. da.

1980-01-01

The phosphate occurrences of Northeastern Para and Northwestern Maranhao were formed by strong lateritic weathering of phosphorus-rich Precambrian rocks. The rock formation affected by those processes were phyllites and schists of the Gurupi Group in Cansa Perna and Pirocaua, a complex of felsic to mafic and ultramafic rocks metamorphosed in the greenschist facies in Itacupim and Trauira and probably phosphoritic sandstone in Jandia. The geology, the mineralogy of phosphates, oxides, hydroxides and silicates, the geochemistry of element distribution (aluminium, silicon, iron, calcium, etc) and trace elements distribution (strontium, rubidium, barium, rare earths, zirconium, niobium uranium, thorium, etc) and the phosphates origin are studied. (C.G.C.)

Strength and Absorption Rate of Compressed Stabilized Earth Bricks (CSEBs Due to Different Mixture Ratios and Degree of Compaction

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Abdullah Abd Halid

2017-01-01

Full Text Available Compressed Stabilized Earth Brick (CSEB is produced by compressing a mixture of water with three main materials such as Ordinary Portland Cement (OPC, soil, and sand. It becomes popularfor its good strength, better insulation properties, and a sustainable product due to its easy production with low carbon emission and less skilled labour required. Different types of local soils usedwill produce CSEB of different physical properties in terms of its strength, durability, and water absorption rate. This study focuses on laterite soil taken from the surrounding local area in Parit Raja, Johor, and CSEB samples are produced based on prototype brick size 100×50×30 mm. The investigations are based on four different degree of compactions (i.e. 1500, 2000, 2500, and 3000 Psi and three different mix proportion ratios of cement:sand:laterite soil (i.e. 1:1:9, 1:2:8, 1:3:7. A total of 144 CSEB samples have been tested at 7 and 28 days curing periods to determine the compressive strength (BS 3921:1985 and water absorption rate (MS 76:1972. It was found that maximum compressive strength of CSEB was 14.68 N/mm2 for mixture ratio of 1:3:7 at 2500 Psi compaction. Whereas, the minimum strengthis 6.87 N/mm2 for 1:1:9mixture ratio at 1500 Psi. Meanwhile, the lowest water absorption was 12.35% for mixture ratio of 1:2:8 at 3000 Psi; while the 1:1:9 mixture ratio at 1500 Psi gave the highest rate of 16.81%. This study affirms that the sand content in the mixture and the degree of compaction would affect the value of compressive strength and water absorption of CSEB.

Relief inversion in the geomorphological evolution of sub-Saharan West Africa

Science.gov (United States)

Butt, C. R. M.; Bristow, A. P. J.

2013-03-01

The geomorphology of much of sub-Saharan West Africa is dominated by the presence of plateaux and plains with ferruginous and, locally, aluminous (bauxitic) duricrusts. The plateaux occur at different elevations and have been correlated as two or more palaeosurfaces across much of the region. The duricrusts have generally been considered to be residual, formed by conformable erosion and chemical wasting of immediately underlying bedrock. This concept has been central to interpretations as diverse as the formation and evolution of the landscape and the development of geochemical exploration models. Recent regolith landform mapping, field observations and experience from mineral exploration in southern Mali and Burkina Faso, however, demonstrate that the duricrusts are mainly ferricretes, i.e., Fe oxide-cemented sediments. These observations require a re-interpretation of the geomorphological evolution of the region during the Cenozoic. The landscape has evolved by several cycles of weathering and erosion-deposition, triggered by climatic, tectonic or other environmental changes. It is proposed that an initial bauxitic/lateritic regolith was partly eroded following uplift and/or a change to a more arid climate, and that the detritus, rather than being removed, was deposited on slopes and valleys. During a subsequent humid period of lateritic weathering, Fe oxide cementation of this detritus formed ferricrete. Dehydration and hardening of the ferricrete after further uplift or aridity increased its resistance to erosion, resulting in relief inversion, with the detritus, in turn, being deposited downslope. This too has been weathered and cemented, to form a younger ferricrete. The occurrence of ferricrete landforms in adjacent countries, noted by field observation and inferred from satellite imagery, demonstrates that relief inversion is a very widespread and important phenomenon in southern Mali, Burkina Faso and adjacent countries in semi-arid West Africa.

Environmental drivers of soil microbial community structure and function at the Avon River Critical Zone Observatory.

Science.gov (United States)

Gleeson, Deirdre; Mathes, Falko; Farrell, Mark; Leopold, Matthias

2016-11-15

The Critical Zone is defined as the thin, permeable layer from the tops of the trees to the bottom of the bedrock that sustains terrestrial life on Earth. The geometry and shape of the various weathering zones are known as the critical zone architecture. At the centre of the Critical Zone are soils and the microorganisms that inhabit them. In Western Australia, the million-year-old stable weathering history and more recent lateral erosion during the past hundreds of thousands of years have created a geomorphic setting where deep weathering zones are now exposed on the surface along the flanks of many lateritic hills. These old weathering zones provide diverse physical and chemical properties that influence near surface pedologic conditions and thus likely shape current surface microbiology. Here, we present data derived from a small lateritic hill on the UWA Farm Ridgefield. Spatial soil sampling revealed the contrasting distribution patterns of simple soil parameters such as pH (CaCl2) and electric conductivity. These are clearly linked with underlying changes of the critical zone architecture and show a strong contrast with low values of pH3.3 at the top of the hill to pH5.3 at the bottom. These parameters were identified as major drivers of microbial spatial variability in terms of bacterial and archaeal community composition but not abundance. In addition, we used sensitive (14)C labelling to assess turnover of three model organic nitrogen compounds - an important biogeochemical functional trait relating to nutrient availability. Though generally rapid and in the order of rates reported elsewhere (t½10h). In conclusion, we have shown that the weathering and erosion history of ancient Western Australia affects the surface pedology and has consequences for microbial community structure and function. Copyright © 2016 Elsevier B.V. All rights reserved.

Alkaline coal fly ash amendments are recommended for improving rice-peanut crops

Energy Technology Data Exchange (ETDEWEB)

Swain, D.K.; Ghosh, B.C. [Agricultural and Food Engineering Department, Indi an Inst. of Technology, Kharagpur, West Bengal (India); Rautaray, S.K. [RRLRRS, Gerua Via-Hajo, Dist-Kamrup, Assam (India)

2007-05-15

A field experiment investigating amendments of organic material including farmyard manure, paper factory sludge and crop residues combined with fly ash, lime and chemical fertilizer in a rice-peanut cropping system was conducted during 1997-98 and 1998-99 at the Indian Institute of Technology, Kharagpur, India. The soil was an acid lateritic (Halustaf) sandy loam. For rice, an N:P:K level of 90:26.2:33.3 kg/ha was supplied through the organic materials and chemical fertilizer to all the treatments except control and fly ash alone. The required quantities of organic materials were added to supply 30 kg N/ha and the balance amount of N, P and K was supplied through chemical fertilizer. Amendment materials as per fertilization treatments were incorporated to individual plots 15 days before planting of rice during the rainy season. The residual effects were studied on the following peanut crop with application of N:P:K at 30:26.2:33.3 kg/ha through chemical fertilizer alone in all treatments, apart from the control. An application of fly ash at 10 t/ha in combination with chemical fertilizer and organic materials increased the grain yield of rice by 11% compared to chemical fertilizer alone. The residual effect of both lime and fly ash applications combined with direct application of chemical fertilizer increased peanut yields by 30% and 24%, respectively, compared to chemical fertilizer alone. Treatments with fly ash or lime increased P and K uptake in both the crops and oil content in peanut kernel compared to those without the amendments. Alkaline coal fly ash proved to be a better amendment than lime for improving productivity of an acid lateritic soil and enriching the soil with P and K.

Rochas-mater da "terra roxa"

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M. Gutmans

1943-09-01

Full Text Available Physico-chemical and mineralogical studies of the soils of the São Paulo State by the Soil Division of The Agronomical Institute proved the existence of different violet soils in South-Brasil and its origin from basaltic rocks. The Brasilian denomination "terra roxa" is already many times translated to "red soil", which is inexact, because the colour "roxa" corresponds to "violet" in English. We must insist on the perfection of Brasilian expression, which gives the shortest and the best characteristic of the true violet soil, derived through the decomposition of basalts and diabases in the São Paulo State. The term "red soil" originated much confusion, because there are in this state many "red soils" of different origins, but the true violet soil is quite unique. The violet colour of this soil appears very beautifully on the clean fields above the diabase hills at the distance of some hundreds of meters. In the state of complete dryness the violet soil becomes coffee brown, but never gets a red colour. The violet soil is the best soil of South America, on the contrary the red soils, which are mostly lateritic, are bad soils. Some exceptions, do exist, of course. The basalts produce laterites and other red soils of better qualities. With the purpose to contribute to the study of the violet and the red soils the present essay was made, describing the basic rocks of South-Brasil, as mother rocks of soils. The basic monograph of Djalma Guimarães "Magmatic Province of South-Brasil" (5, many times mentioned in the petrographic literature, definitively established the principal types and the mineral-components of triassic basic rocks in South-Brasil. We have found some varieties of basic rocks, not ye

The Effects of Eggshell Ash on Strength Properties of Cement-stabilized Lateritic

OpenAIRE

Okonkwo U. N; Odiong I. C; Akpabio E. E

2012-01-01

Eggshell ash obtained by incinerating Fowls’ eggshells to ash has been established to be a good accelerator for cement-bound materials and this would be useful for road construction work at the peak of rainy seasons for reducing setting time of stabilized road pavements. However this should be achieved not at the expense of other vital properties of the stabilized matrix. This is part of the effort in adding value to agricultural materials which probably cause disposal problems. Thus this stu...

Rare earth element mineralogy and geochemistry in a laterite profile from Madagascar

DEFF Research Database (Denmark)

Berger, Alfons; Janots, Emilie; Gnos, Edwin

2014-01-01

. The discovery of this new mineral demonstrates that a natural process exists that that can fractionate REE to such an extent to produce a pure gadolinium end-member mineral. An understanding of such a mechanisms is crucial for the REE geochemistry of low temperature alteration processes as well...

A Study on L-Asparaginase of Nocardia levis MK-VL_113

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Alapati Kavitha

2012-01-01

Full Text Available An enzyme-based drug, L-asparaginase, was produced by Nocardia levis MK-VL_113 isolated from laterite soils of Guntur region. Cultural parameters affecting the production of L-asparaginase by the strain were optimized. Maximal yields of L-asparaginase were recorded from 3-day-old culture grown in modified asparagine-glycerol salts broth with initial pH 7.0 at temperature 30∘C. Glycerol (2% and yeast extract (1.5% served as good carbon and nitrogen sources for L-asparaginase production, respectively. Cell-disrupting agents like EDTA slightly enhanced the productivity of L-asparaginase. Ours is the first paper on the production of L-asparaginase by N. levis.

Application of Moessbauer spectroscopy to iron-57 bauxite

International Nuclear Information System (INIS)

Hill, V.G.; Wynter, C.

1978-01-01

Five different samples from bauxite and related terrains in Jamaica were selected for Moessbauer analysis. Sample 1 is lithiophorite, a lithium aluminum manganese oxide, present as an impurity in Jamaican bauxite; sample 2 is a common red bauxite ore, from Kirkvine, Manchester; sample 3 is a pisolitic bauxite from Reynolds, St. Ann; sample 4 is a red bauxite with pisolites from Mocho; and sample 5 is a shaly material containing some lateritic material which characterizes mining areas. Whereas sample 1 contains fine particles of goettite and/or aluminium substituted goettite, samples 2,3,4,5 contain mixtures of haematite and goettite and/or aluminium substituted goettite in varying concentrations. The findings are consistent with Hill's bauxitization process

A PIXE/PIGE study of gold mineralisation in lateritic terrain, Tanami Desert, Australia

International Nuclear Information System (INIS)

Van Moort, J.C.; Li, X.

1997-01-01

Proton induced X-ray and γ-ray emission (PIXE/PIGE) have been used to analyze major and trace elements in a suite of 140 core samples from around of the Jim's Find South gold anomaly in the Tanami desert, located in heavily weathered terrain. Simultaneous analyses were obtained for 30 elements, ranging in atomic number from 3 Li to 90 Th. The method was chosen because of its speed and the wide range of determination, its flexibility, precision and low detection limits. The regolith powder samples were treated by hot aqua regia before making them into pills. The PIXE/PIGE data of the acid insoluble residue give three factor analysis clusters. The first cluster comprises the elements F, Al, K, V, Mn, Fe, Ga, Rb, W and Au and is essentially related to sericitic wallrock alteration. The second cluster consists of Ti, As, Y, Zr, and Nb and is largely related to resistant minerals. The third cluster consists of Na, Ca and Sr and is interpreted to comprise elements in weatherable minerals such as feldspar and thus represents weathering intensity. While the Rb/K ratio and the product of As x Cu x Ni provide the best surface expression of the gold mineralisation, the Rb/AI ratio provides the best expression of the sericitic alteration around the ore body

Bacterial bioleaching of low grade nickel limonite and saprolite ores by mixotrophic bacteria

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Chaerun Siti Khodijah

2016-01-01

Full Text Available Utilization of indigenous bacteria should be considered to establish a successful biohydrometallurgical process. In this study, mixrotrophic iron-oxidizing bacterial consortia consisting of Comamonas testosteroni, Alicyclobacillus ferrooxydans and Pantoea septic which were isolated from Indonesian mineral ores were examined to determine their abilities to recover nickel from limonite and saprolite ores in the bioleaching experiments using stirred tank reactors. The nickel bioleaching experiments inoculated with the bacterial consortia were carried out using coarse limonite ores and weathered saprolite ores with pulp density of 10% w/v. Abiotic controls were also carried out replacing the inocula by the sterile medium. The bioleaching processes were monitored by measuring Ni and Fe contents and pH of the leaching solution as well as the total bacterial enzymatic activity measured as FDA hydrolytic activity. The effect of leaching on the mineralogy of laterite ores was investigated by the scanning electron microscope equipped with energy-dispersive spectroscopy (SEM-EDS and X-ray powder diffraction (XRD. After 28 days of incubation, the FDA hydrolytic activity was observed in both bioleaching experiments containing limonite (17.2 μg fluorescein/mL and saprolite ores (16.9 μg fluorescein/mL. The leached Ni and Fe in the bioleaching experiments containing limonite ores (30% Ni and 5.6% Fe was greater than that in abiotic controls (1% Ni and 0.1% Fe with the pH range of 2.5 to 3.5. However, the bacterial consortia were less capable of bioleaching of Ni (2.5% with the similar leached Fe (6% from the saprolite ores. In abiotic controls, the medium pH remained relatively constant (pH 6. It was concluded that these bacterial isolated as the consortium were capable of nickel bioleaching (precious metal more effectively than iron (gangue metal, thus being applicable to the commercial processing of the difficult-to-process low-grade nickel laterite ores

Slope Stability Analysis for Shallow Landslides using TRIGRS: A Case Study for Sta. Cruz, Zambales, Philippines

Science.gov (United States)

Mendoza, J. P. A.

2016-12-01

The Philippines, being located in the circum-Pacific, bounded by multiple subduction zones, open seas and ocean, is one of the most hazard-prone countries in the world (Benson, 1997). This widespread recurrence of natural hazards in the country requires much attention for disaster management (Aurelio, 2006). On the average, 21 typhoons enter the Philippine area of responsibility annually with 6-9 making a landfall. Several rainfall-induced landslide events are reported annually particularly during and after the inundation of major typhoons which imposes hazards to communities and causes destruction of properties due to the moving mass and possible flash floods it may induce. Shallow landslides are the most commonly observed failure involving soil-mantled slopes and are considered major geohazards, often causing property damage and other economic loss. Hence numerous studies on landslide susceptibility including numerical models based on infinite slope equation are used in order to identify slopes prone to occurrences of shallow landslides. The study aims to determine the relationships between the slope and elevation to the factor of safety for laterite-mantled topography by incorporating precipitation values in the determination of landslide susceptibility. Using a DEM, flow direction map and slope map of the Sta Cruz (Zambales, Philippines), the FORTRAN based program TRIGRS, was used to generate the values for the factors of safety in the study area. Overlays with a generated slope map and elevation map were used to determine relationships of the mentioned factors and the factors of safety. A slope in a topography mantled with lateritic soil will fail at a slope angle higher than 20 degrees. Generally, the factor of safety decreases as the slope angle increases; this increases the probability and risk of slope failure. Elevation has no bearing on the computation for the factor of safety. The factor of safety is heavily dependent on the slope angle. The value of

Storm event-scale nutrient attenuation in constructed wetlands experiencing a Mediterranean climate: A comparison of a surface flow and hybrid surface-subsurface flow system.

Science.gov (United States)

Adyel, Tanveer M; Oldham, Carolyn E; Hipsey, Matthew R

2017-11-15

Among different Water Sensitive Urban Design options, constructed wetlands (CWs) are used to protect and restore downstream water quality by attenuating nutrients generated by stormwater runoff. This research compared the nutrient attenuation ability during a diverse population of storm events of two CWs: (a) a hybrid CW with multiple alternating surface flow (SF) and laterite-based subsurface flow (SSF) compartments, and (b) a single stage SF CW. Within-storm variability, nutrient concentrations were assessed at 2 to 3-h intervals at both the main inlet and outlet of each CW. Dissolved oxygen concentrations of the surface waters were also monitored at 10-min intervals using high frequency in situ sensors. Nutrient loads into the CWs were observed to be higher when a high rainfall event occurred, particularly after longer antecedent dry conditions. Longer hydraulic retention times promoted higher attenuation at both sites. However, the relative extent of nutrient attenuation differed between the CW types; the mean total nitrogen (TN) attenuation in the hybrid and SF CW was 45 and 48%, respectively. The hybrid CW attenuated 67% total phosphorus (TP) loads on average, while the SF CW acted as a net TP source. Periodic storm events transitioned the lentic CW into a lotic CW and caused riparian zone saturation; it was therefore hypothesized that such saturation of organic matter rich-riparian zones led to release of TP in the system. The hybrid CW attenuated the released TP in the downstream laterite-based SSF compartments. Diel oxygen metabolism calculated before and after the storm events was found to be strongly correlated with water temperature, solar exposure and antecedent dry condition during the pre-storm conditions. Furthermore, the SF CW showed a significant relationship between overall nutrient load attenuation and the change in oxygen metabolism during the storm perturbation, suggesting oxygen variation could be a useful proxy indicator of CW function

/sup 32/P tracer studies on the efficiency of ammonium nitrate phosphates and polyphosphates for growing rice on different soil types

Energy Technology Data Exchange (ETDEWEB)

Sadanandan, A K; Mohanty, S K; Patnaik, S [Central Rice Research Inst., Cuttack (India); Mistry, K B [Bhabha Atomic Research Centre, Bombay (India). Biology and Agriculture Div.

1980-12-01

A pot experiment was conducted with /sup 32/P tagged phosphates to evaluate the efficiency of ammonium nitrate phosphate containing 30, 50 and 70 percent of P in the water soluble form, tri- and tetra-ammonium pyrophosphate, as compared with mono-ammonium ortho-phosphate (MAP) for growing rice on red, laterite and black soils, with regard to recovery of applied P in soil, dry matter production and utilization of applied P by crop at flowering and grain and straw yield at harvest. Ammonium nitrate phosphates containing 50 percent or more of P in the water soluble form could be used for growing rice on all soil types. The pyrophosphates were as efficient as MAP on soils having pH 6.2 and above but less efficient in soils of lower pH.

Progress report to Atomic Energy Commission, January 1, 1970-March 31, 1971

International Nuclear Information System (INIS)

Kaplan, I.R.

Studies were conducted on the following problems: (1) Metal sulfide formation in sediments as a means of trapping heavy metals. (2) Extraction of authigenic U 234 /U 238 from recent sediments as a method of determining rate of sediment accumulation and age dating. (3) Collection of water, sediments and coral from New Caledonia, to determine effective capture of transition metals from weathering of lateritic soil. (4) Transformation and mobilization of uranium in recent reducing sediments. (5) Distribution of transition and base metals in the interstitial water and sediments of near-shore environments. (6) Transformation of organic matter in the sediments and interstitial water of coastal marine environments. (7) Origin and degradation of organic matter in the sediments of the Dead Sea. (8) Composition of interstitial water from JOIDES project from deep ocean cores

32P tracer studies on the efficiency of ammonium nitrate phosphates and polyphosphates for growing rice on different soil types

International Nuclear Information System (INIS)

Sadanandan, A.K.; Mohanty, S.K.; Patnaik, S.; Mistry, K.B.

1980-01-01

A pot experiment was conducted with 32 P tagged phosphates to evaluate the efficiency of ammonium nitrate phosphate containing 30, 50 and 70 percent of P in the water soluble form, tri- and tetra-ammonium pyrophosphate, as compared with mono-ammonium ortho-phosphate (MAP) for growing rice on red, laterite and black soils, with regard to recovery of applied P in soil, dry matter production and utilization of applied P by crop at flowering and grain and straw yield at harvest. Ammonium nitrate phosphates containing 50 percent or more of P in the water soluble form could be used for growing rice on all soil types. The pyrophosphates were as efficient as MAP on soils having pH 6.2 and above but less efficient in soils of lower pH. (author)

Thermal and Infrared Studies of Garnierite from the Soroako Nickeliferous Laterite Deposit, Sulawesi, Indonesia

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Sufriadin Sufriadin

2014-06-01

Full Text Available DOI: 10.17014/ijog.v7i2.137Mineralogical characterization of some garnierite samples from Soroako have been conducted using X-ray diffraction, thermal analysis, and infrared spectroscopy methods. XRD patterns reveal the samples mainly containing the mixture of kerolite (talc-like phase and serpentine with minor smectite, sepiolite, and silica. Thermal analyses of garnierite samples indicated by DTA curves are in good agreement with patterns that have been reported in literature. Three endothermic peaks normally occur in the ranges between 58º C and <800º C illustrating three steps of weight losses: adsorbed, bound, and hydroxyl/crystal water. One additional weight loss in low temperature region of sepiolite is corresponding to the lost of zeolitic water. Infrared spectra appeared in 3800 - 3200 cm-1 region generally exhibit broad absorption bands, indicating low crystallinities of studied samples and can be assigned to the presence of hydroxyl group bonded to octahedral coordination mainly Mg atom. The bands observed at 1660 cm-1, 1639 cm-1, 1637 cm-1, and 1633 cm-1 in all samples indicate water molecules. FTIR spectra displaying the strong bands at 1045 cm-1, 1038 cm-1, and 1036 cm-1 could be related to the presence of Si-O-Si bonds linking to tetrahedral coordination. The strong absorption bands appeared at 511 cm-1, 505 cm-1, 499 cm-1, and 496 cm-1 in respective samples are attributed to divalent cation bonds (e.g. Mg, Ni-O. Both TG/DTA and FTIR seem to be the powerful tool in diagnosing the crystal chemistry of garnierite which is mainly composed of phyllosilicate minerals.

Effect of industrial, municipal and agricultural wastes on peanut in lateritic sandy loam soil

International Nuclear Information System (INIS)

Sarkar, S.; Khan, A.R.

2002-06-01

Modern agriculture, worldwide, depends upon the external application of plant nutrients supplied mostly through chemical fertilizer to meet the crop needs. The natural recycling cannot provide the very large amount of nutrients needed year after year in an intensive cropping system and nutrients being a major constraint harvesting the nutrient energy from biological and industrial waste are of prime importance for maximizing the food grain production in the world. A number of industrial wastes like fly ash from thermal power plants, paper factory sludge from paper factory, sewage sludge from municipal source and farmyard manure from livestock farming are the important waste resources, having potentiality in recycling in agricultural land. When these wastes are recycled through soil for crop production, due to the degradative and assimilative capacity of soil, the pollution hazards of these wastes can be minimized to a greater extent as compared to direct disposing of at the site. Fly ash is a waste product residue resulting from the combustion of pulverised coal in coal-fired power generating station. Physico - chemical analysis of fly ash has revealed the presence of both macro-micro nutrients, which can sustain plant growth. Its application in the agricultural land acts as a liming material and improves crop growth by neutralizing the soil acidity, increasing the water availability for the plants and supplement of nutrients (Adriano et al, 1980, Molliner and Street, 1982, Schnappinger et al, 1975). Application of paper factory sludge has been reported to increase the organic carbon content in soil and nutrient content like P, K, Ca, Mg and micronutrients (Guerini et al, 1994, Muse and Mitchell, 1995). Sludge application also improves the organic carbon content of the soil and availability of nutrients like Ca, K and Mg besides improvement of physical properties (Pitchel and Hayes, 1990). Much is known regarding crop performance and changes in physical and chemical properties of soil due to the application of such organic wastes. However, little is explored regarding the influence of various wastes on soil microbiology and its impact on nodulation and yield of leguminous crop like peanut. Soil biology is a significant component of soil quality and is the catalytic agent responsible for many transformations occurring in soil, most notably the reactions involved in nutrient cycling (Karlen et al, 1997). Thus it is meaningful to evaluate the physical, chemical and biological aspects of soil quality by addition of such organic wastes. The aim of the study was to evaluate the influence of industrial, municipal and agricultural waste on the performance of a leguminous crop like peanut and on the total microbial and Rhizobium population in soil rhizosphere

World production and possible recovery of cobalt from the Kupferschiefer stratiform copper ore

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Pazik Paulina M.

2016-01-01

Full Text Available Cobalt is recognized as a strategic metal and also E-tech element, which is crucial for worlds development. An increasing demand for cobalt forces for searching of new resources that could be explored in European countries. There are many examples of cobalt recoveries, mostly from laterite and sulphide deposits. However, the accurate choice of the technology depends on many factors. The Kupferschiefer stratiform copper ore located in Poland is the biggest deposit of cobalt in Europe. Although KGHM Polska Miedz S.A. recovers many precious metals from this ore, cobalt is not recovered yet. This metal occurs as an accompanying element, mostly in the form of cobaltite (CaAsS, with the average content of 50–80 g/Mg. In this paper a possible recovery of cobalt from the Kupferschiefer ore, with the use of hydrometallurgical methods, was investigated.

Estimation of radiological dose from radon, thoron and their progeny levels in the dwellings of Shivamogga district, Karnataka, India

International Nuclear Information System (INIS)

Rangaswamvi, D.R.; Sannappa, J.; Srinivasa, E.

2018-01-01

Among all natural radiation exposure to man, inhalation of radon, thoron and their progenies are the major contributor (50 %) to the dose from ionizing radiation received by the general population. Based on the results of epidemiological studies in Europe and North America, the World Health Organization (WHO) has recommended reducing the indoor radon reference level from 200 to 100 Bq.m -3 . In view of this, focus has now been given for simultaneous measurement of radon, thoron and their progeny concentration in indoor air and also to estimate radiological dose in the dwellings of the Shivamogga district. The geology of the Shivamogga district comprises different types of rock formation such as granites, schists, magnetites and gneisses, Meta basalt, laterites, quartz and chlorite schist, Graywacke etc. Present study was concentrating more in granite bed rock regions along with their surrounding regions

Development of kenaf mat for slope stabilization

Science.gov (United States)

Ahmad, M. M.; Manaf, M. B. H. Ab; Zainol, N. Z.

2017-09-01

This study focusing on the ability of kenaf mat to act as reinforcement to laterite compared to the conventional geosynthetic in term of stabilizing the slope. Kenaf mat specimens studied in this paper are made up from natural kenaf fiber with 3mm thickness, 150mm length and 20mm width. With the same size of specimens, geosynthetic that obtain from the industry are being tested for both direct shear and tensile tests. Plasticity index of the soil sample used is equal to 13 which indicate that the soil is slightly plastic. Result shows that the friction angle of kenaf mat is higher compared to friction between soil particles itself. In term of resistance to tensile load, the tensile strength of kenaf mat is 0.033N/mm2 which is lower than the tensile strength of geosynthetic.

The Seis Lagos Carbonatite Complex

International Nuclear Information System (INIS)

Issler, R.S.; Silva, G.G. da.

1980-01-01

The Seis Lagos Carbonatite Complex located about 840 Km from Manaus, on the northwestern part of the Estado do Amazonas, Brazil is described. Geological reconnaissance mapping by Radam Project/DNPM, of the southwestern portion of the Guianes Craton, determined three circular features arranged in a north-south trend and outcroping as thick lateritic radioactive hills surrounded by gneisses and mignatites of the peneplained Guianense Complex. Results of core drilling samples analysis of the Seis Lagos Carbonatite Complex are compared with some igneous rocks and limestones of the world on the basis of abundance of their minor and trace elements. Log-log variation diagram of strontium and barium in carbonatite and limestone, exemplifield by South Africa and Angola carbonatites, are compared with the Seis Lagos Carbonatite Complex. The Seis Lagos Carbonatite Complex belongs to the siderite-soevite type. (E.G.) [pt

Geology and mineral resources of central Antioquia Department (Zone IIA), Colombia

Science.gov (United States)

Hall, R.B.; Alvarez A., Jairo; Rico H., Hector

1973-01-01

Antioquian batholith. Displacement along the great Romeral wrench fault may have begun in the Cretaceous. Plutonism continued into the Cenozoic, exemplified by the hornblende-diorite Sabanalarga pluton. Intermontane basins were filled with molasse derived from the erosion of adjacent highlands; Tertiary sedimentation in marshy areas included organic carboniferous matter subsequently converted to lignite or subbituminous coal. The Sabanalarga fault system originated in the Late Tertiary; intermittent displacement continued on the older wrench faults such as the Romeral. Epeirogenic uplift, which probably began in the Pliocene and continued through the Pleistocene and Holocene, brought on renewed erosion which has sculptured the mountains into their present form. Mineral resources in subzone IIA are varied but not of outstanding importance. Gold and silver mining, significant in past centuries, is minor today. Ferruginous laterite on serpentinite once considered as a potential source of iron ore is not economically exploitable. IMN has explored nickeliferous laterite at the extreme northwest corner of subzone IIA; this is a potential resource, exploitable only after exhaustion of the larger and richer nickel laterite deposit at Cerro Matoso, farther to the north and outside the boundaries of Zone If. Known deposits of mercury, chromium, manganese, and copper are small, with limited economic potential. Nonmetallic resources include raw materials for cement, including portland cement. Saprolite clay is widely used in making common red brick and tile, still a dominant construction material in all but the most modern multistory buildings. Aggregate materials are varied and abundant. Kaolin of good quality near La Union is important as a ceramic raw mineral filler. Tertiary subbituminous coal beds are an important energy resource in western subzone IIA, and have a good potential for greater development. Deposits of sodic feldspar, talc, decorative stone, and silica a

Recuperación del cobalto mediante la lixiviación con ácido tartárico de una mena laterítica fuera de balance cubana

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Ballester Pérez, A.

2005-12-01

Full Text Available With the knowledge accumulated today on the perspectives of the bioleaching in the treatment of the lateritic ores of low law and the main limitations of the conventional technologies for treating these minerals, the leaching process is evaluated with organic acid for the recovery of the cobalt present in minerals of low law in nickel. This is an option to keep in mind for the solution of the main socio-environmental and economic problems in the nickel Cuban industry today. In this work it is demonstrated that it is possible to recover around 90 % of the cobalt contained in the lateritic ores of low law in nickel in four days by means of the leaching with tartaric acid. Also the main physical-chemical parameters that influence this process are determined. The perspectives of the organic leaching in the treatment of out-of-balance minerals generated in the nickel. Cuban industry are analyzed.

Mediante la conjugación de los conocimientos acumulados hasta el momento sobre las perspectivas de la biolixiviación en el tratamiento de los minerales lateríticos de baja ley y las principales limitaciones de las tecnologías convencionales de tratamiento de estos minerales, se evalúa el proceso de lixiviación en medio orgánico para la recuperación del cobalto presente en minerales de baja ley en níquel. Esta, constituye una opción a tener en cuenta para la solución de los principales problemas socioambientales y económicos existentes hoy de forma latente en la industria cubana del níquel. En el trabajo se demuestra que es posible recuperar alrededor del 90 % del cobalto contenido en éstas menas fuera de balance, en cuatro días, mediante la lixiviación con el ácido tartárico. Se determinan los principales parámetros físico-químicos que inciden en dicho proceso. Se evalúan las perspectivas de la lixiviación orgánica en el tratamiento de los minerales fuera de balance generados en la industria cubana del níquel.

Potencial de utilização do estrato superior do solo laterítico da cidade de Londrina, Estado do Paraná, como material e apoio de aterros sanitários = Utilization potential of the soil layer in the city of Londrina, Parana State, as material and support for landfill solid wastes

Directory of Open Access Journals (Sweden)

Raquel Souza Teixeira

2006-01-01

Full Text Available Este trabalho apresenta uma avaliação do potencial de utilização da camada de solo laterítico, do perfil característico, da cidade de Londrina, Estado do Paraná, para o uso como material e apoio de aterros sanitários. Neste sentido fez-se necessária uma brevediscussão conceitual sobre resíduos sólidos, tipos de aterros e interação solo-contaminante. Em seguida foi feita uma descrição da localização da área de estudo e das características da camada do solo investigada. A avaliação do solo foi baseada em critérios geotécnicos a partir das características físicas, químicas e mineralógicas do solo, obtidas em ensaio de laboratório e em resultados publicados, em artigos técnicos, tomando-se por base uma pontuação e uma classificação, feitas a partir de atributos sugeridos por Zuquette (1993. A avaliação final, a respeito da utilização da camada de solo laterítico, para a implantação de um aterro sanitário, foi positiva.This paper shows an evaluation of the utilization potential of laterite soil layer, characteristic of the city of Londrina, Paraná State, as material and support for landfill solid wastes. At first, weprovided a brief definition of the solid residue, types of embankments, soil-contaminating interaction and contaminating processes. Then, we described the study area location and the layer characteristics of the soil under investigation. The soil evaluation was based on geotechnical criteria regarding physical, chemical and mineralogical characteristics of the soil, which were obtained from a laboratory experiment and from results published in technical articles. Grading and classification were done according to the attributes suggested by Zuquette (1993. The final evaluation on the use of the layer of laterite soil for the implantation of the sanitary bank was positive.

Past and Present Weathering Recorded in Cretaceous Shale Samples from Colombia - Implications for Paleoenvironmental Reconstructions

Science.gov (United States)

Mahoney, C.; März, C.; Wagner, T.

2016-12-01

It is well known that for geochemical studies on ancient rocks, outcrop samples can be compromised by present-day weathering. This raises the fundamental question, if only outcrop samples are available, how reliable can paleoenvironmental reconstructions be? To answer this question, shale samples have been gathered from Cretaceous outcrops of the Eastern Cordillera of Colombia, and analysed by XRF and Fe speciation in order to investigate paleo-redox conditions in this margin basin of the Proto-Atlantic. The samples are consistently depleted (relative to average shale) in redox-related trace metals and in total Fe indicating oxic conditions, whereas Fe speciation (highly reactive over total Fe) indicates anoxic conditions. We ask if this depletion in trace metals and total Fe is due to a lack of primary supply from the depositional environment, or if is it caused by modern oxidative outcrop weathering in this tropical mountainous setting? Our results from artificial weathering experiments confirm that certain trace metals U, Zn and Mo are easily leached from the samples, whereas Fe is quantitatively retained in the samples due to conversion of pyrite and siderite to Fe oxides. Pristine samples from wells in the adjacent Middle Magdalena Valley Basin (MMV) also exhibit total Fe depletion, but are up to 2000-fold enriched in Mo. This combined evidence indicates that the depletion of trace metals may be due to contemporary weathering, but there has to be a paleoenvironmental reason behind the low total Fe signature. The Guiana Shield was the probable source of sediment to the Cretaceous basin. The Chemical Index of Alteration suggest the source of detrital material was initially highly weathered (average 83, maximum 95). Ancient laterites have been identified on the Guiana Shield, and retention of Fe in these laterites may explain the low Fe input into the Eastern Cordillera basin. These results confirm that trace metal-based redox proxies may be seriously affected by

TRANSITION FROM CARBONATE PLATFORM TO PELAGIC DEPOSITION (MID JURASSIC- LATE CRETACEOUS, VOURINOS MASSIF, NORTHERN GREECE

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NICOLAOS CARRAS

2004-03-01

Full Text Available A Jurassic- Cretaceous carbonate succession crops out along the Zyghosti Rema, Kozani (Northern Greece. The substratum consists of the ophiolitic succession of the Vourinos Massif (Pelagonian Domain: serpentinites tectonically overlain by basalts, with thin lenses of radiolarian cherts of middle Bathonian age. The contact with the overlying Jurassic limestones is tectonic. Eight informal units have been distinguished within the Mesozoic limestones, from the base upwards. (A bioclastic, intraclastic and oolitic packstone (Callovian- Oxfordian. (B bioclastic packstone and coral boundstone (Oxfordian . (C bioclastic and oncoidal wackestone with Clypeina jurassica (Oxfordian- Upper Kimmeridgian. (D (Upper Kimmeridgian- Portlandian: oncoidal packstone and rudstone (facies D1; intraclastic and bioclastic grainstone and packstone (facies D2; neptunian dykes with intraclastic and bioclastic wackestone and packstone filling (facies D3; neptunian dykes with Fe-Mn rich laterite filling and with pink silty filling of early Late Cretaceous age. An unconformity surface, due to emersion and erosion of the platform during the latest Jurassic- Early Cretaceous, is overlain by (E intraclastic, bioclastic packstone and grainstone (Cenomanian. (F massive body of debrites with coral, echinoderm, algae and rudist large clasts (facies F1 (Cenomanian; turbiditic beds of bioclastic, intraclastic and lithoclastic rudstone and grainstone (facies F2. (G thin bedded bioclastic mudstone and wackestone with planktonic foraminifers and radiolarians, alternating with turbiditic beds of bioclastic, intraclastic packstone and rudstone and with conglomeratic levels and slumped beds of the previous turbidites (upper Santonian- lower Campanian. (H: bioclastic packstone with planktonic foraminifers (facies H1 (lower Campanian - ?Maastrichtian; amalgamated turbiditic beds of bioclastic wackestone and packstone with planktonic foraminifers (facies H2; turbiditic beds of bioclastic

Organic complexation and translocation of ferric iron in podzols of the Negro River watershed. Separation of secondary Fe species from Al species

Science.gov (United States)

Fritsch, E.; Allard, Th.; Benedetti, M. F.; Bardy, M.; do Nascimento, N. R.; Li, Y.; Calas, G.

2009-04-01

The development of podzols in lateritic landscapes of the upper Amazon basin contributes to the exportation of organic carbon and associated metals in the black waters of the Negro River watershed. We have investigated the distribution of Fe III in the clay-size fraction of eight organic-rich horizons of waterlogged plateau podzols, to unravel the weathering conditions and mechanisms that control its transfer to the rivers. The speciation and amount of Fe III stored in residual mineral phases of laterites, or bound to organic compounds of weakly and well-expressed podzols, were determined by electron paramagnetic resonance spectroscopy combined with chemical analyses. Reducing conditions restrict the production of organo-Fe complexes in the subsoil B-horizons of waterlogged podzols and most of the Fe 2+ released from the dissolution of Fe-oxides is exported to the rivers via the perched groundwater. However, significant amounts of diluted Fe III bound to organic ligands (Fe IIIOM) and nano Fe-oxides are produced at the margin of the depression in the topsoil A horizons of weakly expressed podzols due to shorter periods of anoxia. The downward translocation of organically bound metals from topsoil A to subsoil B-horizons of podzols occurs in shorter distances for Fe than it does for Al. This separation of secondary Fe species from Al species is attributed to the physical fractionation of their organic carriers in texture contrasted B-horizons of podzols, as well as to the effect of pH on metal speciation in soil solutions and metal binding onto soil organic ligands (mostly for Al). This leads us to consider the topsoil A horizons of weakly expressed podzols, as well as the subsoil Bh horizon of better-expressed ones, as the main sources for the transfer of Fe IIIOM to the rivers. The concentration of Fe IIIOM rises from soil sources to river colloids, suggesting drastic biogeochemical changes in more oxygenated black waters of the Negro River watershed. The

Studies on the mobility of some heavy metals and transuranic radionuclides in major Indian soil types

International Nuclear Information System (INIS)

D'Souza, T.J.; Vyas, B.N.; Athalye, V.V.; Ramachandran, V.; Mistry, K.B.

1983-01-01

Studies on the mobility of the heavy metals, chromium, lead, zinc and transuranic radionuclides plutonium and americium in three major Indian soils, namely a vertisol-pellustert (black soil), an oxisol (laterite soil) and an entisol-haplaquent (alluvial soil), indicated that more than 98% of the surface-deposited pollutants were retained in the top 0 to 2.5 cm layer when leached with rain-water. In general, the mobility of these elements was either unaffected or marginally reduced at high doses of added organic matter as compared with controls. However, leaching with dilute solutions of (10 -4 M-bar) EDTA, EDDHA and DTPA resulted in enhancement of the mobility of all these pollutants with a high degree of chelate specificity for individual ions, depending upon the soil type. Rapid formation of stable soluble Cr-EDDHA, Pu-DTPA and Am-DTPA complexes facilitated the leaching of these pollutants from the contaminated soils. (author)

Chromium isotope fractionation during oxidative weathering of a modern basaltic weathering profile

DEFF Research Database (Denmark)

D'Arcy, Joan Mary; Døssing, Lasse Nørbye; Frei, Robert

Chromium can be used as a tracer of redox sensitive environmental processes. In soils Cr (III) is inert, immobile and resides predominantly in minerals, clays and oxides. Cr (VI) is toxic, soluble and mobile and is usually lost from the soil to local run off. Chromium isotopes have been shown...... to fractionate under both reducing and oxidizing conditions [1, 2]. Recent studies on d53Cr isotopes in laterite soils show that oxidative weathering of Cr-bearing rocks is accompanied by an isotopic fractionation, where by the lighter isotopes are retained in the residual soil and the heavier isotope...... is enriched in local runoff [1]. This study aims to quantify the stable Cr isotope composition of two modern basaltic weathering profiles, to help better understand the processes that oxidize inert Cr (III) to toxic Cr (VI). We sampled basaltic weathering profiles and associated river waters from areas of two...

Ion exchange for treatment of industrial effluents

International Nuclear Information System (INIS)

Moreno Daudinot, Aurora Maria; Ge Leyva, Midalis

2016-01-01

The acid leaching and ammoniacal carbonate technologies of laterite respectively, are responsible for the low quality of life of the local population, the big deforested areas due to the mining tilling, the elevated contents of solids in the air and waters, as well as the chemical contamination by metals presence, the acidity or basicity of the effluents of both industries, that arrive through the river and the bay to aquifer's mantle. The ion exchange resins allow ions separation contained in low concentrations in the solutions, where the separation of these elements for solvents, extraction or another chemical methods would be costly. Technological variants are proposed in order to reduce the impact produced on the flora and the fauna, by the liquid effluents of nickel industry, by means of ion exchange resins introduction as well as the recuperation of metals and their re incorporation to the productive process. (Author)

Nickel recovery from electric arc furnace slag by magnetic separation

Directory of Open Access Journals (Sweden)

Sakaroglou Marianna

2017-01-01

Full Text Available During the pyrometallurgical treatment of the nickel-bearing laterite in the plant of G.M.M. S.A. LARCO, slag is produced after treatment in electric-arc furnace (EAF that contains 0.10 to 0.20 % Ni. Taking into account the great quantity of slag produced per year, the recovery of nickel from the EAF slag will add benefits to the entire process. The target of the current work is to investigate the possibility of nickel recovery from EAF slag by magnetic separation. To meet the target, the effect of the following parameters was studied: grain size, magnetic field intensity, thickness of slag layer, moisture content, and re-grinding of the coarser slag particles. The results show that it is possible to obtain a magnetic product with nickel grade close to that of the primary raw material or even better, with sufficient nickel recovery.

The application of U-isotopes to assess weathering in contrasted soil-water regime in Brazil.

Science.gov (United States)

Rosolen, Vania; Bueno, Guilherme Taitson; Bonotto, Daniel Marcos

2018-02-01

This paper presents the use of U-series radionuclides 238 U and 234 U to evaluate the biogeochemical disequilibrium in soil cover under a contrasted soil-water regime. The approach was applied in three profiles located in distinct topographical positions, from upslope ferralitic to downslope hydromorphic domain. The U fractionation data was obtained in the samples representing the saprolite and the superficial and subsuperficial soil horizons. The results showed a significant and positive correlation between U and the Total Organic Carbon (TOC). Soil organic matter has accumulated in soil due to hydromorphy. There is no evidence of positive correlation between U and Fe, as expected in lateritic soils. The advance of the hydromorphy on Ferralsol changes the weathering rates, and the ages of weathering are discussed as a function of the advance of waterlogged soil conditions from downslope. Also, the bioturbation could represent the other factor responsible to construct a more recent soil horizon. Copyright © 2017 Elsevier Ltd. All rights reserved.

Investigation of electro-kinetic methods for soil decontamination

International Nuclear Information System (INIS)

Shabanova, A.N.

2000-01-01

The choices of effective methods for ecological system decontamination, their perfection and introduction into practical use have been actual tasks for the Ural region. The objective of this work has been to study the potentials of electrical kinetics method of ISOTRON Corporation (US) for decontamination of the Urals soils. Results obtained have shown the method proposed to be usable for decontaminating some types of soils from strontium and plutonium; it is low effective for decontamination in the area of South-Urals radioactive plume. Thus, a low effectiveness can be expected in podsolic and leached laterite characterized by a high content of loamy sand and sandy soils, as well as for sobby-podsolic ones. The method can be promising for decontamination of soils and wastes from chemical contaminants, such as Zn, Ni, Cu, Pb, Hg, and others. Important advantages of this method compared to others have been its simplicity, small amount of wastes, and feasibility of decontamination in areas difficult to access. (authors)

Diversity and community structure of dung beetles (Coleoptera: Scarabaeinae associated with semi-urban fragmented agricultural land in the Malabar coast in southern India

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K.S. Venugopal

2012-07-01

Full Text Available An evaluation of the diversity and community structure of dung beetles associated with semiurban agricultural land in the Malabar coast of southern India revealed that urbanization has led to decreased diversity compared to regional forests, and has affected the community status of dung beetles. However, contrary to expectations, species richness was observed to be equivalent to rural agricultural fields in the region. Low abundance of prominent agricultural habitat species indicates that the study area has changed as a result of habitat modification/urbanization, and the prevailing conditions are not ideal for the establishment of the most common species in agriculture belts. Prominence of two less common species, Tiniocellus spinipes and Caccobius vulcanus, indicates these generalist urban adaptable (synanthropic species have become increasingly widespread and locally abundant. The low abundance of tunnelers and rollers is attributed to fragmentation of the urban agricultural belt, low mammalian diversity and dung availability, and the hard nature of the laterite soil in the Malabar coast region.

Distribution and assemblages of large branchiopods (Crustacea: Branchiopoda of northern Western Ghats, India

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Sameer M. Padhye

2015-01-01

Full Text Available The present study is a report on the distribution and assemblages of large branchiopods from the Western Ghats of Maharashtra. Different types of water bodies were sampled including pools on lateritic outcrops. Eight species of large branchiopods were found in 72 samples collected over a period of 4 years. We found 7 large branchiopod species in rock pools, while the cyclestheriid Cyclestheria hislopi was observed only in rivers and water reservoirs. In twenty-five percent of the samples multiple species co-occurred with a maximum of 4 species in a single sample. Streptocephalus dichotomus was the most commonly observed species while Streptocephalus sahyadriensis was noted only in rock pools. Altitude and aquatic vegetation were identified as important factors for the distribution of large branchiopods in the studied area. Triops granarius was the species most commonly found to be co-occurring with other species, followed by S. sahyadriensis. Cyclestheria hislopi and Eulimnadia indocylindrova always occurred alone. 

Chromium isotope fractionation during oxidative weathering of the Antrim Basalts: An insight into the global Cr geochemical cycle

DEFF Research Database (Denmark)

D'Arcy, Joan Mary; Døssing, Lasse Nørbye; Frei, Robert

in this area has focused on laterites, a unique soil type produced by intense tropical weathering. To evaluate if this phenomenon is unique to tropical regions we have measured the Cr isotope composition (d53/52Cr ‰) of soils and river water from the Antrim Plateau, Northern Ireland, a marine temperate climate....... Cr is enriched in the soil horizon relative to basaltic bedrock. Cr isotope fractionation is minimal with d53/52Cr values (-0.27 + 0.02 ‰ to -0.15 + 0.03‰) near to bedrock values (-0.25 + 0.04 ‰) indicating a lack of oxidative weathering. However, local river waters are enriched in isotopically heavy...... Cr as immobile Cr (III). The Cr (VI) lost from the system is insufficient to effect the isotopic composition of the soils. This study together with Cr data from other basaltic river catchments has found that the d53/52Cr of river water is catchment specific [1] and is controlled by local soil forming...

Placer mineral resources of Tamil Nadu

International Nuclear Information System (INIS)

Anil Kumar, V.

2016-01-01

Tamil Nadu, the southernmost state with second longest coast line in India has many placer heavy mineral deposits. These deposits contain economically important light heavy minerals like ilmenite, rutile, leucoxene, monazite, zircon, garnet, sillimanite, kyanite and non-economic minerals like pyroxenes, amphiboles and magnetite along with associated accessory minerals like staurolite, epidote, spinel, biotite and tourmaline. Geologically, granulitic rocks, principally Khondalites (garnet-sillimanite-graphite gneisses), charnockites and granitic gneisses bordered by sedimentary rocks are exposed along the eastern coastal plains of the Tamil Nadu. The principal highland areas, as for example, Shavaroys, Nilgiris, Palni-Kodaikanal Hills and Cardomom hills consists primarily of Charnockites. The margins of highland show a gradation into less metamorphosed rocks generally of amphibolite facies. The khondalites are found south of Kodaikanal massif. Anorthosites and layered mafic complexes occur at Sittampundi, Kadavur areas. Alkaline rocks and carbonatites are prominent at Simalpatti, Sevattur and Sivamalai. Coastal sedimentaries include, Gondwanas, Cretaceous, Tertiary and Quaternary rocks along with lateritic soils and beach sands

Stagnation of the exploitation of Al ores and the depression of world prices of Al

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Slavkovský Jozef

1999-03-01

Full Text Available In the contribution, data on Al – a metal of the 20th century are compiled together with the problems of genesis of the Al mineral raw ma-terials as well as types of bauxite and Al-laterite deposits. Furthermore, an overview of the world exploitation of bauxite during 1935-1980 is given along with the prognoses to 2000 and present situation (1992-1996. Overviews of the production of Al follows, providing its rela-tion to the bauxite exploitation. Contrary to the prognoses, a stabilization or stagnation has been observed in the exploitation of bauxite and production of Al during nineties, which a tendency is directly reflected in the world price of this commodity. When analyzing the Al prices for a longer period, some serious deviations can be noticed, that however presently represent a long-term minimum. We hope the stagnation of the production and the price decline are only temporary and new possibilities of the utilization of Al will be found soon.

Plant-associated fluorescent Pseudomonas from red lateritic soil: Beneficial characteristics and their impact on lettuce growth.

Science.gov (United States)

Maroniche, Guillermo A; Rubio, Esteban J; Consiglio, Adrián; Perticari, Alejandro

2016-11-25

Fluorescent Pseudomonas are ubiquitous soil bacteria that usually establish mutualistic associations with plants, promoting their growth and health by several mechanisms. This makes them interesting candidates for the development of crop bio-inoculants. In this work, we isolated phosphate-solubilizing fluorescent Pseudomonas from the rhizosphere and inner tissues of different plant species growing in red soil from Misiones, Argentina. Seven isolates displaying strong phosphate solubilization were selected for further studies. Molecular identification by rpoD genotyping indicated that they belong to different species within the P. fluorescens and P. putida phylogenetic groups. Screening for in vitro traits such as phosphate solubilization, growth regulators synthesis or degradation, motility and antagonism against phytopathogens or other bacteria, revealed a unique profile of characteristics for each strain. Their plant growth-promoting potential was assayed using lettuce as a model for inoculation under controlled and greenhouse conditions. Five of the strains increased the growth of lettuce plants. Overall, the strongest lettuce growth promoter under both conditions was strain ZME4, isolated from inner tissues of maize. No clear association between lettuce growth promotion and in vitro beneficial traits was detected. In conclusion, several phosphate solubilizing pseudomonads from red soil were isolated that display a rich array of plant growth promotion traits, thus showing a potential for the development of new inoculants.

Geochemical behavior under tropical weathering of the Barama-Mazaruni greenstone belt at Omai gold mine, Guiana Shield

Energy Technology Data Exchange (ETDEWEB)

Voicu, G. [Universite du Quebec a Montreal (Canada). Dept. des Sciences de la Terre et de l' Atmosphere; Omai Gold Mines, Georgetown (Guyana); Bardoux, M. [Universite du Quebec a Montreal (Canada). Dept. des Sciences de la Terre et de l' Atmosphere

2002-07-01

Mineralogical, petrographical, and geochemical studies of the weathering profile have been carried out at Omai Au mine, Guyana. The area is underlain by felsic to mafic volcanic and sedimentary rocks of the Barama-Mazaruni Supergroup, part of the Paleoproterozoic greenstone belts of the Guiana Shield. Tropical rainy climate has favoured extensive lateritization processes and formation of a deeply weathered regolith. The top of the weathering profile consists of lateritic gravel or is masked by the Pleistocene continental-deltaic Berbice Formation. Mineralogical composition of regolith consists mainly of kaolinite, goethite and quark, and subordinately sericite, feldspar, hematite, pyrite, smectite, heavy minerals, and uncommon mineral phases (nacrite, ephesite, corrensite, guyanaite). A specific feature of the weathering profile at Omai is the preservation of fresh hydrothermal pyrite in the saprolith horizon. Chemical changes during the weathering processes depend on various physicochemical and structural parameters. Consequently, the depth should not be the principal criterion for comparison purposes of the geochemical behavior within the weathering profile, but rather an index that measures the degree of supergene alteration that has affected each analyzed sample, independently of the depth of sampling. Thus, the mineralogical index of alteration (MIA) can provide more accurate information about the behavior of major and trace elements in regolith as opposed to unweathered bedrock. It can also aid in establishing a quantitative relationship between intensity of weathering and mobility (leaching or accumulation) of each element in each analyzed sample. At Omai, some major and trace elements that are commonly considered as immobile (ex: TiO{sub 2}, Zr, etc.) during weathering could become mobile in several rock types and cannot be used to calculate the mass and volume balance. In addition, due to higher ''immobile element'' ratios, the

Morphology and morphometry of upland lakes over lateritic crust, Serra dos Carajás, southeastern Amazon region.

Science.gov (United States)

Silva, Marcio S DA; Guimarães, José T F; Souza Filho, Pedro W M; Nascimento Júnior, Wilson; Sahoo, Prafulla K; Costa, Francisco R DA; Silva Júnior, Renato O; Rodrigues, Tarcísio M; Costa, Marlene F DA

2018-05-17

High-resolution satellite images, digital elevation models, bathymetric and sedimentological surveys coupled with statistical analysis were used to understand the physical environment and discuss their influence on water quality of the five upland lakes of Serra Sul dos Carajás, southeast Amazonia. The lakes have mid-altitude ranges (elevation), very small (catchment) and shallow to very shallow (central basins). Based on the length, area and volume, Violão and TI (Três Irmãs)-3 lakes may present large vertical movements of the water due to wind action and weakly stratified waters. Trophic conditions based on depth and shore development (Ld) parameters must be used with caution, since Amendoim Lake is relatively deep, but it is oligotrophic to ultra-oligotrophic. Ld values suggest that the lakes are circular to subcircular and are likely formed by solution process, as also suggested by volume development. TI-2 Lake is only presenting convex central basin and has highest dynamic ratio (DR), thus it may have high sedimentation and erosion rates. Based on the relationship between studied parameters, morphometric index and DR likely influence temperature and dissolved oxygen of waters of TI-2 Lake due to its depth profile and wind-induced surface mixing. Nevertheless, water quality parameters are controlled by catchment characteristics of the lakes.

Soil Stabilization with Lime for the Construction of Forest Roads

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Reginaldo Sérgio Pereira

2018-02-01

Full Text Available ABSTRACT The mechanical performance of soil stabilization using lime to improve forest roads was assessed. This study was conducted with lateritic soil (LVAd30 using lime content of 2% in the municipality of Niquelândia, Goiás state, Brazil. Geotechnical tests of soil characterization, compaction, and mechanical strength were performed applying different compaction efforts and curing periods. The results showed that lime content significantly changed the mechanical performance of natural soil, increasing its mechanical strength and load-carrying capacity. Compaction effort and curing time provided different responses in the unconfined compressive strength (UCS and California Bearing Ratio (CBR tests. The best UCS value (786.59 kPa for the soil-lime mixture was achieved with modified compaction effort and curing time of 28 days. In the CBR test, soil-lime mixtures compacted at intermediate and modified efforts and cured for 28 days were considered for application as subbase material of flexible road pavements, being a promising alternative for use in layers of forest roads.

Microbial leaching of chromite overburden from Sukinda mines, Orissa, India using Aspergillus niger

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Biswas, Supratim; Samanta, Saikat; Dey, Rajib; Mukherjee, Siddhartha; Banerjee, Pataki C.

2013-08-01

Leaching of nickel and cobalt from two physical grades (S1, 125-190 μm, coarser and S3, 53-75 μm, finer) of chromite overburden was achieved by treating the overburden (2% pulp density) with 21-d culture filtrate of an Aspergillus niger strain grown in sucrose medium. Metal dissolution increases with ore roasting at 600°C and decreasing particle size due to the alteration of microstructural properties involving the conversion of goethite to hematite and the increase in surface area and porosity as evident from X-ray diffraction (XRD), thermogravimetry-differential thermal analysis (DT-TGA), and field emission scanning electron microscopy (FESEM). About 65% Ni and 59% Co were recovered from the roasted S3 ore employing bioleaching against 26.87% Ni and 31.3% Co using an equivalent amount of synthetic oxalic acid under identical conditions. The results suggest that other fungal metabolites in the culture filtrate played a positive role in the bioleaching process, making it an efficient green approach in Ni and Co recovery from lateritic chromite overburden.

Groundwater vulnerability assessment using hydrogeologic and geoelectric layer susceptibility indexing at Igbara Oke, Southwestern Nigeria

Science.gov (United States)

Oni, T. E.; Omosuyi, G. O.; Akinlalu, A. A.

2017-12-01

Groundwater vulnerability assessment was carried out at Igbara Oke Southwestern Nigeria, with a view to classify the area into vulnerability zones, by applying the electrical resistivity method, using Schlumberger electrode arrays with maximum electrode separation (AB/2) of 65 m in (41) different locations for data acquisition. Geoelectric parameters (layer resistivity and thickness) were determined from the interpreted data. The study area comprises four geoelectric layers (topsoil, lateritic layer, weathered/fractured layer and fresh basement). The geoelectric parameters of the overlying layers across the area were used to assess the vulnerability of the underlying aquifers to near-surface contaminants with the aid of vulnerability maps generated. Three models were compared by maps using geo-electrically derived models; longitudinal conductance, GOD (groundwater occurrence, overlying lithology and depth to the aquifer) and GLSI (geoelectric layer susceptibility indexing). The total longitudinal conductance map shows the north central part of the study area as a weakly protected (0.1-0.19) area, while the northern and southern parts have poor protective capacity (septic tank, refuse dump should be cited far from groundwater development area.

Progress in bioleaching: part B: applications of microbial processes by the minerals industries.

Science.gov (United States)

Brierley, Corale L; Brierley, James A

2013-09-01

This review presents developments and applications in bioleaching and mineral biooxidation since publication of a previous mini review in 2003 (Olson et al. Appl Microbiol Biotechnol 63:249-257, 2003). There have been discoveries of newly identified acidophilic microorganisms that have unique characteristics for effective bioleaching of sulfidic ores and concentrates. Progress has been made in understanding and developing bioleaching of copper from primary copper sulfide minerals, chalcopyrite, covellite, and enargite. These developments point to low oxidation-reduction potential in concert with thermophilic bacteria and archaea as a potential key to the leaching of these minerals. On the commercial front, heap bioleaching of nickel has been commissioned, and the mineral biooxidation pretreatment of sulfidic-refractory gold concentrates is increasingly used on a global scale to enhance precious metal recovery. New and larger stirred-tank reactors have been constructed since the 2003 review article. One biooxidation-heap process for pretreatment of sulfidic-refractory gold ores was also commercialized. A novel reductive approach to bioleaching nickel laterite minerals has been proposed.

Ni, Co recovery study and Fe by acid leaching in columns; Estudio de la extraccion de Ni, Co y Fe en lateritas por medio de lixiviacion acida en columnas

Energy Technology Data Exchange (ETDEWEB)

Yorio, C. di; Betancourt, E.; Vivas, R.; Rus, J.

2006-07-01

In the following work the possibility of the mic kel recovery by hydrometallurgy extraction for nickeliferous laterite is studied. The work looks for to study the technical viability of the extraction of nickel and cobalt by means of the application of heap leaching. The ore is chemically and physically characterized with the purpose of analyzes its composition and mineral phase, by means of x-rays diffraction, quantitative chemical analysis and elementary chemical analysis by electronic microscopy. One the ore is characterized, it is mixed with sulfuric acid to relations 0.05; 0.1 and 0.2 g acid/g to agglomerated pellets and paste, with the aim to improve the percolation in column, due to the argillaceous nature of the ore leaching rate ranged from 0.305 to 1.06 x 10 l/h m''2 and in the agglomerate condition of the percolation l/h m''2 improves at interval 3.05 to 6.11 x 100 l/h m''2. (Author)

The Effects of Different Curing Methods on the Compressive Strength of Terracrete

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O. Alake

2009-01-01

Full Text Available This research evaluated the effects of different curing methods on the compressive strength of terracrete. Several tests that included sieve analysis were carried out on constituents of terracrete (granite and laterite to determine their particle size distribution and performance criteria tests to determine compressive strength of terracrete cubes for 7 to 35 days of curing. Sand, foam-soaked, tank and open methods of curing were used and the study was carried out under controlled temperature. Sixty cubes of 100 × 100 × 100mm sized cubes were cast using a mix ratio of 1 part of cement, 1½ part of latrite, and 3 part of coarse aggregate (granite proportioned by weight and water – cement ratio of 0.62. The result of the various compressive strengths of the cubes showed that out of the four curing methods, open method of curing was the best because the cubes gained the highest average compressive strength of 10.3N/mm2 by the 35th day.

[Spatiotemporal variation of soil pH in Guangdong Province of China in past 30 years].

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Guo, Zhi-Xing; Wang, Jing; Chai, Min; Chen, Ze-Peng; Zhan, Zhen-Shou; Zheng, Wu-Ping; Wei, Xiu-Guo

2011-02-01

Based on the 1980s' soil inventory data and the 2002-2007 soil pH data of Guangdong Province, the spatiotemporal variation of soil pH in the Province in past 30 years was studied. In the study period, the spatial distribution pattern of soil pH in the Province had less change (mainly acidic), except that in Pearl River Delta and parts of Qingyuan and Shaoguan (weak alkaline). The overall variation of soil pH was represented as acidification, with the average pH value changed from 5.70 to 5.44. Among the soil types in the Province, alluvial soil had an increased pH, lateritic red soil, paddy soil, and red soil had a large decrement of pH value, and lime soil was most obvious in the decrease of pH value and its area percentage. The soil acidification was mainly induced by soil characteristics, some natural factors such as acid rain, and human factors such as unreasonable fertilization and urbanization. In addition, industrialization and mining increased the soil pH in some areas.

Utilization of soil and fertilizer zinc by maize (Zea mays) and moong (Phaseolus aureus Roxb.) from some Indian soils

International Nuclear Information System (INIS)

Iyengar, B.R.V.; Deb, D.L.

1977-01-01

Utilization of soil and fertilizer zinc by maize (Zea mays) and moong (Phaseolus aureus Roxb.) was studied under greenhouse conditions in ten soils belonging to three important soil groups of India viz. alluvial, red and laterite using two levels of labelled zinc sulphate. The efficiency of utilization of fertilizer zinc was found to be higher at 10 ppm level of application in both the crops as compared with 20 ppm level of applied zinc. The total utilization of fertilizer zinc by both the crops in different soils ranged from 0.47 to 1.34 percent and 0.41 to 0.95 percent at 10 and 20 ppm level of applied zinc, respectively. Application of fertilizer zinc resulted in a decrease in the uptake of soil zinc. The utilization of fertilizer zinc was found to be negatively correlated with soil pH but the interaction of different soil characters seemed to have determined the efficiency of fertilizer use by both the crops. The efficiency of fertilizer zinc utilization was found to be low in moong as compared with maize. (author)

Constitutive mass balance relations between chemical composition, volume, density, porosity, and strain in metasomatic hydrochemical systems: Results on weathering and pedogenesis

Science.gov (United States)

Brimhall, George H.; Dietrich, William E.

1987-03-01

Relations characterizing the chemical, physical, and mechanical changes resulting from metasomatic hydrochemical processes are developed using mass balance models which formally link chemical composition to bulk density, mineral density, volumetric properties, porosity, and amount of deformation (strain). Rigorous analysis of aqueous solute transport effects is then made possible in a variety of porous media flow environments including chemical weathering, pedogenesis (soil formation), diagenesis, ore deposition and enrichment, and metamorphism. Application of these linear constitutive relations to chemical weathering profiles shows that immobile and locally mobile chemical elements, with masses conserved on the scale of soil profiles, can be accurately identified from analysis of appropriate data arrays and then used as natural geochemical tracers to infer the nature and extent of hydrochemical weathering processes and volume changes during pedogenesis. Assumptions commonly made in the past about the supposed immobility of certain elements, e.g., Ti and Zr, become unnecessary. Quantitative differentiation between the effects of residual and supergene fractionation is then easily made. These methods are applied to Ni-rich laterites developed by weathering of ultramafic rocks, showing that during ordinary residual enrichment, Ni is concentrated by as much as 4× protolith peridotite concentrations. This occurs simply by silicate mineral dissolution and removal of chemical elements other than Ni ( e.g., Mg) with a corresponding reduction in saprolite density and increase in bulk porosity without significant deformation. In contrast, laterites with mineable concentrations of Ni which are similarly undeformed (such as the Nickel Mountain Mine in Riddle, Oregon) have experienced, in addition to residual enrichment, strong supergene enrichment by fractionation of ore elements between a leached zone from which Ni is extracted and a complementary enriched zone positioned

Bamboo as Soil Reinforcement: A Laboratory Trial

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Alhaji Mohammed MUSTAPHA

2008-12-01

Full Text Available A lateritic soil classified as A-6 under AASHTO soil classification system was reinforced with 0, 1, 2 and 3 bamboo specimens at laboratory trial level to evaluate its unconfined compressive strength (UCS and modulus of rigidity. The soil specimens were molded in cylindrical form of 38mm diameter and 76mm height while the bamboo specimens were trimmed in to circular plates of 34mm diameter and 3mm thickness. The trial soil specimens are: soil specimen without bamboo specimen (0 bamboo, soil specimen with one bamboo specimen in the center (1 bamboo, soil specimen with one bamboo specimen on top and one at the bottom (2 bamboos and soil specimen with one bamboo specimen on top, center and bottom (3 bamboos. Though, the dry density of the molded soil specimen decreased from 1.638Mg/m3 at 0 bamboo to 1.470Mg/m2 at 3 bamboos, the UCS increased from 226KN/m2 at 0 bamboo to 621KN/m2 at 3 bamboos. Also, for each of the 3 percentage strains (0.5, 1.0 and 1.5% considered, the modulus of rigidity increased with bamboo specimens.

Physical-chemical study of hydroxi-phosphates and associated minerals occurring in the Pirocaua Plateau (MA) and Jandia hill (PA)

International Nuclear Information System (INIS)

Reymao, M. de F.F.

1983-01-01

A lateritic profile rich in alumino-calcic and aluminum hidroxi-phosphates (Pirocaua, MA), and another also rich in alumino-calcic and containning iron and calcium hidroxi-phosphates (Jandia, PA) has been investigated in order to elucidate the formation of the secondary minerals and the trace element behaviour during tropical weathering. For such purposes it was decided to use X-ray diffractometry and chemical analysis and it was pointed out the applicability of infrared absorption spectroscopy and differential thermal analysis for the mineral characterization. In order to relate the geochemical alterations it was included a theoretical thermodynamic study. Infrared absorption spectroscopy and differential thermal analysis have been demonstrated to be valuables methods for studying minerals. Results are presented which demonstrate the usefullness of these techniques. These studies show that it is now possible to correlate differential thermal analysis and infrared data with that from other techniques (chemical analysis, X-ray diffraction patterns) and that the methods yields valuable supplemental information. Theoretical calculations and the use of thermodynamic data (standard free energie and solubility products) reveal some important conclusions about chemical equilibria, mineral formation, solubility and stability relations. (Author) [pt

Different depth intermittent sand filters for laboratory treatment of synthetic wastewater with concentrations close to measured septic tank effluent.

Science.gov (United States)

Rodgers, M; Walsh, G; Healy, M G

2011-01-01

The objective of this study was to apply hydraulic and chemical oxygen demand (COD) loading rates at the upper limits of the design criteria for buried sand filters to test the sand filter depth design criteria. Over a 274-day study duration, synthetic effluent with a strength of domestic wastewater was intermittently dosed onto two sand filters of 0.2 m diameter, with depths of 0.3 and 0.4 m. Hydraulic and organic carbon loading rates of 105 L m(-2) d(-1) and 40 g COD m(-2) d(-1), respectively, were applied to the filters. The filters did not clog and had good effluent removal capabilities for 274 and 190 days, respectively. However, the 0.3 m-deep filter did experience a reduced performance towards the end of the study period. In the 0.3 and 0.4 m-deep filters, the effluent COD and SS concentrations were less than 86 and 31 mg L(-1), respectively, and nitrification was nearly complete in both these columns. Ortho-phosphorus (PO(4)-P) removal in fine sand and laterite 'upflow' filters, receiving effluent from the 0.3 m-deep filter, was 10% and 44%, respectively.

An avifaunal case study of a plateau from Goa, India: an eye opener for conservation of plateau ecosystems

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Minal Desai

2012-03-01

Full Text Available The lateritic plateaux typical of the midlands between the Western Ghats and the coastal plains of the Arabian Sea are known to be a unique ecosystem with a sizeable endemic flora. However, there is a total lack of studies on the faunal diversity of these plateaux, which are currently experiencing enormous anthropogenic pressures. We conducted a year-long study on the avifauna of the Taleigao Plateau, Goa. The Taleigao Plateau harbours 114 species of birds, accounting for 37% of the avifaunal diversity of the state. The resident bird population did not vary significantly through the seasons. Among the migrant birds, Rosy Starling Sturnus roseus was particularly partial to the plateau. Besides, five species of larks, grassland specialists were also recorded on the plateau. However, the absence of forest birds like the Malabar Pied Hornbill and the Indian Grey Hornbill (recorded earlier and the predominance of habitat generalists like the House Crow and the Jungle Myna seemed to be the offshoot of heavy anthropogenic pressures on the plateau. It is recommended that at least some plateaux in the belt deserve to be protected from the impact of unsustainable developmental process

First record of Annonaceae wood for the Neogene of South America, Amazon Basin, Brazil

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Emilio Alberto Amaral Soares

Full Text Available ABSTRACT: The relief of the regions of Manaus and Itacoatiara, Central Amazon, is supported by Neogene siliciclastic rocks, bounded at the base and top by lateritic paleosols and covered by quaternary sedimentary deposits from the Solimões-Amazon river system. This unit is informally assigned to the Novo Remanso Formation, consists of usually reddish and ferruginized sandstones, conglomerates and pelites, with few identified fossil records, a fact that has hindered its stratigraphic position, and the paleoenvironmental reconstruction of the last phase of the Amazon Basin settling. This study describes, for the first time, the occurrence of fossil wood in outcroppings of the left bank of the Amazon River, where anatomical and morphological data has enabled its characterization to the species level. Thus, the data marks the record of the Annonaceae in South America, as well as the depositional processes related to incorporation of organic material in the sandy layer and the fossilization processes that allowed its preservation. In an unprecedented way, this study has described Duguetiaxylon amazonicum nov. gen and sp. and provided information on the anatomical and systematic character, as well as data on plant-insect interaction, and a better understanding of the family.

Identification of areas of recharge and discharge using Landsat-TM satellite imagery and aerial photography mapping techniques

Science.gov (United States)

Salama, R. B.; Tapley, I.; Ishii, T.; Hawkes, G.

1994-10-01

Aerial photographs (AP) and Landsat (TM) colour composites were used to map the geomorphology, geology and structures of the Salt River System of Western Australia. Geomorphic features identified are sand plains, dissected etchplain, colluvium, lateritic duricrust and rock outcrops. The hydrogeomorphic units include streams, lakes and playas, palaeochannels and palaeodeltas. The structural features are linear and curvilinear lineaments, ring structures and dolerite dykes. Suture lines control the course of the main river channel. Permeable areas around the circular granitic plutons were found to be the main areas of recharge in the uplands. Recharge was also found to occur in the highly permeable areas of the sandplains. Discharge was shown to be primarily along the main drainage lines, on the edge of the circular sandplains, in depressions and in lakes. The groundwater occurrence and hydrogeological classification of the recharge potential of the different units were used to classify the mapped areas into recharge and discharge zones. The results also show that TM colour composites provide a viable source of data comparable with AP for mapping and delineating areas of recharge and discharge on a regional scale.

Fluorescent and X-ray diffraction analysis for industrial wastes of the Comandante Pedro Soto Alba plant

International Nuclear Information System (INIS)

Herrera, V.

1980-05-01

It is presented a qualitative X-ray elemental fluorescence and diffraction analysis of the low-nickel portion (deands) of Cuban lateritic ores from Moa and Nicaro, the tailings of the Cuba nickel plant Comandante Pedro Soto Alba (in Moa) and its magnetic concentrated fractions (results of enrichment test in magnetizing roasting and wet magnetic separation). In all samples as main phase hematite (α-Fe 2 O 3 ) is observed. In all deands samples there were also high concentrations of goethite (α-FeOOH) and aluminium hydroxide (Al(OH) 3 ). In the Nicaro deands, in addition to name above phases, a modification of delta-iron hydroxide, with Ni and/or Co substitutions in the forms delta-(Fesub(0,67)Nisub(0,33))OOH, delta-(Fesub(0,67)Cosub(0,33))OOH or delta-(Fesub(0,67)Nisub(x)Cosub(0,33-x))OOH seems possible. In Moa tailings besides the hematite, the more abundant phases are a basic hydrated aluminium sulphate and gypsum. The magnetic enriched fractions are practically by a spinel of the maghemite type, and chromium seems to be included into the spinel lattice. (author)

Quaternary tectonic control on channel morphology over sedimentary low land: A case study in the Ajay-Damodar interfluve of Eastern India

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Suvendu Roy

2015-11-01

Full Text Available The style of active tectonic on the deformation and characterization of fluvial landscape has been investigated on three typical skrike-slip fault zones of the Ajay-Damodar Interfluve (ADI in Eastern India through field mapping, structural analysis and examination of digital topography (ASTER-30 m, multi-spectral imageries, and Google Earth images. Channel morphology in Quaternary sediment is more deformed than Cenozoic lateritic tract and igneous rock system by the neotectonic activities. The structural and lithological controls on the river system in ADI region are reflected by distinct drainage patterns, abrupt change in flow direction, offset river channels, straight river lines, ponded river channel, marshy lands, sag ponds, palaeo-channels, alluvial fans, meander cutoffs, multi-terrace river valley, incised compressed meander, convexity of channel bed slope and knick points in longitudinal profile. Seven morphotectonic indices have been used to infer the role of neotectonic on the modification of channel morphology. A tectonic index map for the ADI region has been prepared by the integration of used morphotectonic indices, which is also calibrated by Bouguer gravity anomaly data and field investigation.

The genesis of surficial uranium deposits

International Nuclear Information System (INIS)

Boyle, D.R.

1984-01-01

Surficial uranium deposits can form in such diverse environments as calcareous-dolomitic-gypsiferous fluvial and aeolian valley sediments in hot arid and semi-arid regions, oxidizing and reducing alkaline and saline playas, highly organic and/or clay-rich wetland areas, calcareous regoliths in arid terranes, laterites, lake sediments, and highly fractured zones in igneous and metamorphic basement complexes. Formation of ore is governed by the interrelationships between source of ore-forming elements, mechanisms of migration, environment of deposition, climate, preservation, tectonic history and structural framework. The principal factors controlling mobilization of ore-forming elements from source to site of deposition are the availability of elements in source rocks, presence of complexing agents, climate, nature of source rock regolith and structure of source rock terrane. The major processes governing precipitation of uranium in the surficial environment are reduction mechanisms, sorption processes, dissociation of uranyl complexes, change in redox states of ore-forming constituents, evaporation of surface and groundwaters, change in partial pressure of dissolved carbon dioxide, changes in pH, colloidal precipitation, and mixing of two or more surface and groundwaters. One or a number of these processes may be actively involved in ore formation. (author)

Groundwater exploration using 2D Resistivity Imaging in Pagoh, Johor, Malaysia

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Kadri, Muhammad; Nawawi, M. N. M.

2010-12-01

Groundwater is a very important component of water resources in nature. Since the demand of groundwater increases with population growth, it is necessary to explore groundwater more intensively. In Malaysia only less than 2% of the present water used is developed from groundwater. In order to determine the existence of usable groundwater for irrigation and drinking purposes in Pagoh, 2D resistivity imaging technique was utilized. The 2-D resistivity imaging technique utilized the Wenner—Schlumberger electrode array configuration because this array is moderately sensitive to both horizontal and vertical structures. Three lines were surveyed for groundwater delineation purpose The length for each survey lines are 400 meters. At Pagoh, the survey site shows the existence of groundwater. It is indicated by the resistivity values about 10-100 ohm-m. The maximum depth of investigation survey is 77 meters. In general the results show that the subsurface is made up of alluvium and clay and the high resistivity values of more than 1000 ohm-m near the surface is due laterite and the end of the depth can be interpreted as mixture of weathered material or bedrock.

PRODUCTIVITY OF MAIZE (ZEA MAYS) BASED INTERCROPPING SYSTEM DURING KHARIF SEASON UNDER RED AND LATERITIC TRACT OF WEST BENGAL

OpenAIRE

M K MANDAL; M BANERJEE; H BANERJEE; A ALIPATRA; G C MALIK

2014-01-01

A FIELD EXPERIMENT WAS CARRIED OUT DURING KHARIF SEASON OF 2010 AND 2011 AT SRINIKETAN RESEARCH FARM, VISVA BHARTI, WEST BENGAL. THE GRAIN YILED AND STOVER YIELD OF MAIZE WERE SIGNIFICANTLY HIGHER IN CASE OF PURE STAND OF MAIZE THAN EITHER OF ITS INTERCROPPING SYSTEMS WITH LEGUMES, WHILE THE COB YILED WAS HIGHEST IN THE MAIZE WITH SOYBEAN (1:2) INTERCROPPING SYSTEM AND IT WAS STATISTICALLY AT PAR WITH THE YIELD OBTAINED IN SOLE MAIZE. THE GRAIN YIELD OF LEGUMES WAS HIGHEST IN MAIZE WITH GROUN...

A PIXE/PIGE study of lateritic gold mineralization from the regolith of the Mystery Zone, Mt Percy, Western Australia

International Nuclear Information System (INIS)

Li, X.; Van Moort, J.C.

1998-01-01

PIXE/PIGE have been utilized extensively in the search for gold and volcanic hosted massive sulphide deposits, using rock powders from relatively fresh rock. The present study uses regolith samples, from which weathering products (oxides, hydroxides, carbonates, sulphates and clay) have been removed by sequential treatment with aqua regia and sulphuric acid. The samples come from the Mystery Zone, Mt Percy, Kalgoorlie, comprising both mineralized and barren samples. The acid insoluble residue consist essentially of quartz with minor sericite. The PlXE/PIGE data from the acid insoluble residue shows that the geochemical character of W, Al, K, Ca, V, Ga, Rb, Rb/K and Rb/Al could correctly define the location of underlying mineralization at depth. The ratio of Ti/Zr remained relatively constant in different geological units and can be used to distinguish lithologies. (authors)

A PIXE/PIGE study of lateritic gold mineralization from the regolith of the Mystery Zone, Mt Percy, Western Australia

Energy Technology Data Exchange (ETDEWEB)

Li, X.; Van Moort, J.C. [Tasmania Univ., Sandy Bay, TAS (Australia). Dept. of Geology

1998-06-01

PIXE/PIGE have been utilized extensively in the search for gold and volcanic hosted massive sulphide deposits, using rock powders from relatively fresh rock. The present study uses regolith samples, from which weathering products (oxides, hydroxides, carbonates, sulphates and clay) have been removed by sequential treatment with aqua regia and sulphuric acid. The samples come from the Mystery Zone, Mt Percy, Kalgoorlie, comprising both mineralized and barren samples. The acid insoluble residue consist essentially of quartz with minor sericite. The PlXE/PIGE data from the acid insoluble residue shows that the geochemical character of W, Al, K, Ca, V, Ga, Rb, Rb/K and Rb/Al could correctly define the location of underlying mineralization at depth. The ratio of Ti/Zr remained relatively constant in different geological units and can be used to distinguish lithologies. (authors). Extended abstract. 5 refs.

Effect of the use nickeliferous laterite and pumice as additives in the performance and durability of the Portland cement

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María Carolina Rueda-Gualdrón

2016-01-01

Full Text Available En este trabajo se evalúa el comportamiento puzolánico de la laterita niquelífera de Cerromatoso (Córdoba y la pumita de Cemex (Boyacá en la preparación de morteros según normas NTC para agregados finos. Los morteros se prepararon con adiciones de 2,5%, 5% y 10% como sustitutos del cemento Portland tipo I, los cuales fueron sometidos a ensayos de resistencia mecánica antes y después de ser sometidos a ambientes extremos (altas temperaturas y ataques químicos como H2 SO4 y MgSO4 . Los resultados demuestran cómo estos materiales alternativos incrementan o disminuyen su grado de puzolanidad, así como el efecto de estos aditivos al interior de las mezclas de mortero en el tiempo, demostrando propiedades similares con relación a los morteros preparados con cemento Portland tipo I. Por lo tanto, los morteros tienen una respuesta aceptable ante las condiciones evaluadas, aunque es posible mejorar su desempeño y durabilidad, colaborando no solo con el ahorro energético en la producción del cemento Portland tipo I sino también en el uso de aditivos alternativos que permitan mitigar el impacto ambiental provocado por la industria cementera.

Effect of the use nickeliferous laterite and pumice as additives in the performance and durability of the Portland cement

OpenAIRE

María Carolina Rueda-Gualdrón; Karen Milena Vega-Nuñez; Carlos Alberto Ríos-Reyes

2016-01-01

En este trabajo se evalúa el comportamiento puzolánico de la laterita niquelífera de Cerromatoso (Córdoba) y la pumita de Cemex (Boyacá) en la preparación de morteros según normas NTC para agregados finos. Los morteros se prepararon con adiciones de 2,5%, 5% y 10% como sustitutos del cemento Portland tipo I, los cuales fueron sometidos a ensayos de resistencia mecánica antes y después de ser sometidos a ambientes extremos (altas temperaturas y ataques químicos como H2 SO4 y MgSO4 ). Los resu...

Cobalt mineral exploration and supply from 1995 through 2013

Science.gov (United States)

Wilburn, David R.

2011-01-01

The global mining industry has invested a large amount of capital in mineral exploration and development over the past 15 years in an effort to ensure that sufficient resources are available to meet future increases in demand for minerals. Exploration data have been used to identify specific sites where this investment has led to a significant contribution in global mineral supply of cobalt or where a significant increase in cobalt production capacity is anticipated in the next 5 years. This report provides an overview of the cobalt industry, factors affecting mineral supply, and circumstances surrounding the development, or lack thereof, of key mineral properties with the potential to affect mineral supply. Of the 48 sites with an effective production capacity of at least 1,000 metric tons per year of cobalt considered for this study, 3 producing sites underwent significant expansion during the study period, 10 exploration sites commenced production from 1995 through 2008, and 16 sites were expected to begin production by 2013 if planned development schedules are met. Cobalt supply is influenced by economic, environmental, political, and technological factors affecting exploration for and production of copper, nickel, and other metals as well as factors affecting the cobalt industry. Cobalt-rich nickel laterite deposits were discovered and developed in Australia and the South Pacific and improvements in laterite processing technology took place during the 1990s and early in the first decade of the 21st century when mining of copper-cobalt deposits in Congo (Kinshasa) was restricted because of regional conflict and lack of investment in that country's mining sector. There was also increased exploration for and greater importance placed on cobalt as a byproduct of nickel mining in Australia and Canada. The emergence of China as a major refined cobalt producer and consumer since 2007 has changed the pattern of demand for cobalt, particularly from Africa and

Application of persistent scatterers interferometry for surface displacements monitoring in N5E open pit iron mine using TerraSAR-X data, in Carajás Province, Amazon region

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Filipe Altoé Temporim

Full Text Available ABSTRACT: Carajás Mineral Province, Amazon region, is the most important one in Brazil. Vale S.A. Company has the right to operate in the area of the N5E mine. The work is conducted on rock alteration products of low geomechanical quality related to sandstones, siltstones, and a lateritic cover. In order to monitor ground deformation, 33 TerraSAR-X images covering the period of March 2012-April 2013 were used in the investigation. An interferometric synthetic aperture radar (InSAR approach based on permanent scatterer interferometry (PSI using an interferometric point target analysis algorithm was applied. Results demonstrated that most of the area was considered stable during the time span of the image acquisition. However, persistent scatterers (PSs with high deformation rates were mapped over a landfill probably related to settlements. To validate the PSI data, graphs were generated with the displaced information based on topographic measurements in the field. The graphs showed that the surface deformations during TSX-1 runway coverage are within the miner’s safety threshold and do not present a risk of major problems. The PSI data provided a synoptic and detailed view of the deformation process that affects the mining complex without the need of field campaign or instrumentation.

Soil characterization using patterns of magnetic susceptibility versus effective radium concentration

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F. Girault

2011-08-01

Full Text Available Low-field magnetic susceptibility χ_m and effective radium concentration EC_Ra, obtained from radon emanation, have been measured in the laboratory with 129 soil samples from Nepal. Samples along horizontal profiles in slope debris or terrace scarps showed rather homogeneous values of both χ_m and EC_Ra. One sample set, collected vertically on a lateritic terrace scarp, had homogeneous values of EC_Ra while χ_m increased by a factor of 1 to 10 for residual soils and topsoils. However, for a set of samples collected on three imbricated river terraces, values of EC_Ra, homogeneous over a given terrace, displayed a gradual increase from younger to older terraces. By contrast, χ_m showed more homogeneous mean values over the three terraces, with a larger dispersion, however, for the younger one. Similarly, Kathmandu sediments exhibited a large increase in EC_Ra from sand to clay layers, while χ_m increased moderately. The combination of χ_m and EC_Ra, thus, provides a novel tool to characterize quantitatively various soil groups and may be of interest to distinguish modes of alteration or deposition histories.

Land application of waste waters in the Alligator Rivers region, Northern Territory - environmental constraints on design and operation

International Nuclear Information System (INIS)

Kearns, A.

1986-01-01

The existing uranium mines in the Alligator River Region presently operate under a no release water management regime for water stored within the designated restricted release zones (RRZ). This water is of variable quality ranging from rainwater influenced by runoff from the mill sites and ore stockpiles to mill process water stored within the trailings repositories. There is a pressing need to reduce the volume of stored RRZ water at Nabarlek as a prerequisite to decommissioning. There is also a requirement at Ranger to rapidly reduce the volume of stored water in the mine pit at the end of the season to allow the mining of ore. Land application of RRZ water by spray irrigation has been investigated at both sites because it offers the benefits of applying chemical constituents in the wastewater within a clearly defined irrigation area. the environmental planning for the design of a land application system involves calculations of the chemical load in the wastewater and evaluation of the assimilative capacity of the soil-plant system. The monsoon climate, lateritic soil and fluctuating water table creates a unique set of environmental constraints and conditions in which to design and operate a successful land application system for the treatment of stored water at minesites within ecologically sensitive areas

The influence of grain size, grain color, and suspended-sediment concentration on light attenuation: why fine-grained terrestrial sediment is bad for coral reef ecosystems

Science.gov (United States)

Storlazzi, Curt; Norris, Benjamin; Rosenberger, Kurt

2015-01-01

Sediment has been shown to be a major stressor to coral reefs globally. Although many researchers have tested the impact of sedimentation on coral reef ecosystems in both the laboratory and the field and some have measured the impact of suspended sediment on the photosynthetic response of corals, there has yet to be a detailed investigation on how properties of the sediment itself can affect light availability for photosynthesis. We show that finer-grained and darker-colored sediment at higher suspended-sediment concentrations attenuates photosynthetically active radiation (PAR) significantly more than coarser, lighter-colored sediment at lower concentrations and provide PAR attenuation coefficients for various grain sizes, colors, and suspended-sediment concentrations that are needed for biophysical modeling. Because finer-grained sediment particles settle more slowly and are more susceptible to resuspension, they remain in the water column longer, thus causing greater net impact by reducing light essential for photosynthesis over a greater duration. This indicates that coral reef monitoring studies investigating sediment impacts should concentrate on measuring fine-grained lateritic and volcanic soils, as opposed to coarser-grained siliceous and carbonate sediment. Similarly, coastal restoration efforts and engineering solutions addressing long-term coral reef ecosystem health should focus on preferentially retaining those fine-grained soils rather than coarse silt and sand particles.

Critical parameters in the production of ceramic pot filters for household water treatment in developing countries.

Science.gov (United States)

Soppe, A I A; Heijman, S G J; Gensburger, I; Shantz, A; van Halem, D; Kroesbergen, J; Wubbels, G H; Smeets, P W M H

2015-06-01

The need to improve the access to safe water is generally recognized for the benefit of public health in developing countries. This study's objective was to identify critical parameters which are essential for improving the performance of ceramic pot filters (CPFs) as a point-of-use water treatment system. Defining critical production parameters was also relevant to confirm that CPFs with high-flow rates may have the same disinfection capacity as pots with normal flow rates. A pilot unit was built in Cambodia to produce CPFs under controlled and constant conditions. Pots were manufactured from a mixture of clay, laterite and rice husk in a small-scale, gas-fired, temperature-controlled kiln and tested for flow rate, removal efficiency of bacteria and material strength. Flow rate can be increased by increasing pore sizes and by increasing porosity. Pore sizes were increased by using larger rice husk particles and porosity was increased with larger proportions of rice husk in the clay mixture. The main conclusions: larger pore size decreases the removal efficiency of bacteria; higher porosity does not affect the removal efficiency of bacteria, but does influence the strength of pots; flow rates of CPFs can be raised to 10-20 L/hour without a significant decrease in bacterial removal efficiency.

Assessing the geo-electric characteristics of Basement Complex rocks and its implication for groundwater prospecting in Ilorin Metropolis, Nigeria

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I. P. Ifabiyi

2016-12-01

Full Text Available In Basement Complex rocks where rainfall is seasonal, water provision in dry season depends on regolith aquifer. For effective exploitation of groundwater resources, it is reasonable that geophysical investigation be conducted before development of well. In many instances, geophysical surveys may be expensive or nonexistent. Hence, there is a need for spatial analysis which might advise water engineers within such environments. Vertical Electrical Soundings (VES data of 53 locations conducted with ABEM SAS-1000 terrameter using Schlumberger electrode configuration were obtained from the hydrogeology Department of Kwara state Ministry of Water Resources and Lower Niger River Basin and Rural Development Authority, Ilorin. VES locational coordinates were recorded using handheld GPS device. Sound curves were evaluated by partial curve matching approach and computer iteration using WinResist. The results depict six geo-electric regional successions, namely: top soil, lateritic clay, weathered basement, fairly-hard basement, thin fractured and hard basement. The geo-electric succession identified was plotted in Surfer 12 environment, using kriging interpolation method to show spatial distribution pattern of this zone. The spatial pattern is expected to give an insight to the nature of spatial variability of geo-electric layers and assist drillers as well as water resources policy makers in their operations.

Soil-vegetation relationships on a banded ironstone 'island', Carajás Plateau, Brazilian Eastern Amazonia.

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Nunes, Jaquelina A; Schaefer, Carlos E G R; Ferreira Júnior, Walnir G; Neri, Andreza V; Correa, Guilherme R; Enright, Neal J

2015-01-01

Vegetation and soil properties of an iron-rich canga (laterite) island on the largest outcrop of banded-iron formation in Serra de Carajás (eastern Amazonia, Brazil) were studied along a topographic gradient (738-762 m asl), and analyzed to test the hypothesis that soil chemical and physical attributes play a key role in the structure and floristic composition of these plant communities. Soil and vegetation were sampled in eight replicate plots within each of the four vegetation types. Surface (0-10 cm) soil samples from each plot were analyzed for basic cations, N, P and plant species density for all species was recorded. CCA ordination analysis showed a strong separation between forest and non-forest sites on the first axis, and between herbaceous and shrubby campo rupestre on the second axis. The four vegetation types shared few plant species, which was attributed to their distinctive soil environments and filtering of their constituent species by chemical, physical and hydrological constraints. Thus, we can infer that Edaphic (pedological) factors are crucial in explaining the types and distributions of campo rupestre vegetation associated with ferruginous ironstone uplands (Canga) in Carajás, eastern Amazonia, therefore the soil properties are the main drivers of vegetation composition and structure on these ironstone islands.

Cassava; African perspective on space agriculture

Science.gov (United States)

Katayama, Naomi; Njemanze, Philip; Nweke, Felix; Space Agriculture Task Force, J.; Katayama, Naomi; Yamashita, Masamichi

Looking on African perspective in space agriculture may contribute to increase diversity, and enforce robustness for advanced life support capability. Cassava, Manihot esculentaand, is one of major crop in Africa, and could be a candidate of space food materials. Since resource is limited for space agriculture in many aspects, crop yield should be high in efficiency, and robust as well. The efficiency is measured by farming space and time. Harvest yield of cassava is about 41 MJ/ m2 (70 ton/ha) after 11 months of farming. Among rice, wheat, potato, and sweet potato, cassava is ranked to the first place (40 m2 ) in terms of farming area required to supply energy of 5 MJ/day, which is recommended for one person. Production of cassava could be made under poor condition, such as acidic soil, shortage of fertilizer, draught. Laterite, similar to Martian regolith. Propagation made by stem cutting is an advantage of cassava in space agriculture avoiding entomophilous or anemophilous process to pollinate. Feature of crop storage capability is additional factor that determines the efficiency in the whole process of agriculture. Cassava root tuber can be left in soil until its consumption. Cassava might be an African contribution to space agriculture.

Natural history of the narrow endemics Ipomoea cavalcantei and I. marabaensis from Amazon Canga savannahs.

Science.gov (United States)

Babiychuk, Elena; Kushnir, Sergei; Vasconcelos, Santelmo; Dias, Mariana Costa; Carvalho-Filho, Nelson; Nunes, Gisele Lopes; Dos Santos, Jorge Filipe; Tyski, Lourival; da Silva, Delmo Fonseca; Castilho, Alexandre; Fonseca, Vera Lucia Imperatriz; Oliveira, Guilherme

2017-08-08

Amazon comprises a vast variety of ecosystems, including savannah-like Canga barrens that evolved on iron-lateritic rock plateaus of the Carajás Mountain range. Individual Cangas are enclosed by the rain forest, indicating insular isolation that enables speciation and plant community differentiation. To establish a framework for the research on natural history and conservation management of endemic Canga species, seven chloroplast DNA loci and an ITS2 nuclear DNA locus were used to study natural molecular variation of the red flowered Ipomoea cavalcantei and the lilac flowered I. marabaensis. Partitioning of the nuclear and chloroplast gene alleles strongly suggested that the species share the most recent common ancestor, pointing a new independent event of the red flower origin in the genus. Chloroplast gene allele analysis showed strong genetic differentiation between Canga populations, implying a limited role of seed dispersal in exchange of individuals between Cangas. Closed haplotype network topology indicated a requirement for the paternal inheritance in generation of cytoplasmic genetic variation. Tenfold higher nucleotide diversity in the nuclear ITS2 sequences distinguished I. cavalcantei from I. marabaensis, implying a different pace of evolutionary changes. Thus, Canga ecosystems offer powerful venues for the study of speciation, multitrait adaptation and the origins of genetic variation.

Use of a 55Fe radioisotope for the determination of titanium in laterite samples via energy dispersive X-ray fluorescence

International Nuclear Information System (INIS)

La Brecque, J.J.

1978-01-01

A rapid method for the determination of titanium in geochemical samples using a 55 Fe radioisotope at the extraction source coupled to a Si(Li) detector and a PDP-11/05 computer is described. A representative sample of about 200 g is ground in a large mortar and pestle before it is passed through a 20 mesh sieve. The 20 mesh sample is mixed thoroughly and quartered, then a 5 g subsample is passed completely through a 150 mesh sieve. Both the sample and internal standard K 2 Cr 2 O 7 are dried at 105 deg C before a 250 mg portion of each is weighed and thoroughly mixed. Three 50-100 mg portions are placed in separate sample holders. The sample holder is a simple card with a 1.5 cm diameter opening in which the sample is inserted between two layers of Magic Scotch tape. The relative standard deviation for a thin sample about 100 mg in weight is less than 4% and it is achieved in a fluorescent time of 100 sec. Data are given for the use of two different internal standards, KBrO 2 and K 2 Cr 2 O 7 , the latter being more precise. The values for five international reference standards determined by this method are in agreement with the reported values. (T.G.)

Applications of Moessbauer spectroscopy to the structural characterization of minerals and products of the country 's mining - metallurgical industry

International Nuclear Information System (INIS)

Herrera Palma, Victoria; Cruz Inclan, Carlos Manuel

2016-01-01

Since the seventies of the past century Moessbauer Spectroscopy (MS) has been systematically and successfully applied at CEADEN in the study and characterization of lateritic and other iron-rich ores, and different products of their industrial processing as well. Due to their high iron and chrome content these materials seemed to be attractive as raw material for the production of several enriched fractions in metallurgical applications. Such studies showed that the systematic application of MS combined with X- Ray Diffraction and other techniques like neutron Diffraction, Thermal and Calorimetric analysis and Optical and Electron Microscopies, has allowed a higher level of accuracy in the crystallographic characterization, and the phase composition and other specific properties assessment. As examples in this direction, in the present paper results of the study on two different iron-bearing materials are reported: a) magnetite of Mina Grande (in Santiago de Cuba), and b) Monitoring of a proposed process using concentration tables for chrome enrichment from tailings of the nickel plant 'Hector Ramos Latour' at Holguin, both areas located in the east of Cuba. It is evidenced that a right combination of 57 Fe Moessbauer Spectroscopy with other mentioned methods is nowadays the wisest and most efficient way for a thorough identification and characterization of iron-bearing mineral ores and products in mining and metallurgical industry. (Author)

Symbiotic N fixation and fertilizer nitrogen use efficiency in legume-cereal intercropping systems

International Nuclear Information System (INIS)

Jena, D.; Misra, C.

1990-01-01

On a lateritic soil at Bhubaneswar short duration rice, finger millet, maize, groundnut, pigeon pea, black gram were grown alone or as intercrop in microplots (1mx1m). Thirty days after germination, 15 N tagged urea (3% a.e.) solutions was applied to all the treatments so as to provide 40 kg N ha -1 for the cereals, 10 kg n ha -1 for the legumes and 20 kg N ha -1 for cereal plus legumes. The results show the fertilizer efficiency values to be nearly 62 to 69 per cent for rice, 53 per cent for maize and 22 percent for finger millet. These values were 12 to 17 per cent for pigeon pea, 18 percent for black gram and 23 percent for groundnut. Averaged over the cropping system and fertilizer doses, the nitrogen fixed by legumes, viz,pigeon-pea, black gram and groundnut were 16.3, 15.5 and 17.5 kg ha -1 , respectively, within 60 days of crop growth. Horse gram grown as a sequence crop during the dry season (after the harvest of wet season crops) using the residual soil water and nutrients appears to utilize the residual 15 N better when it follows the non-legumes compared with that when it follows the legumes. (author). 5 refs., 5 tabs

Nitrogen fixation by free-living microorganisms in tropical rice soils using labelled fertilizer. Part of a coordinated programme on isotope techniques in studies of biological nitrogen fixation for the dual purpose of increasing crop production and decreasing nitrogen fertilizer use to conserve the environment

International Nuclear Information System (INIS)

Rao, V.R.

1981-11-01

Both acetylene-reduction and 15 N techniques were used to study heterotrophic N fixation in the rhizosphere of rice plants. Soils subjected to flooding in 4 soil types in both greenhouse and the field were found to stimulate greater heterotrophic nitrogen fixation than moist soils. The addition of organic materials, in particular, cellulose and rice straw, in general, enhanced nitrogen fixed by heterotrophic organisms living in the rhizosphere of rice plants. The highest amount of N fixed was 38 kg N/ha, and was obtained in a flooded lateritic soil to which had been added cellulose. Heterotrophic nitrogen fixation was influenced by soil type. In this study, the lowest value for fixed N was recorded in an acid sulphate soil of low pH. The addition of increasing amounts of inorganic nitrogen fertilizer in the form of ammonium sulphate suppressed rhizospheric nitrogen fixation in all soils, but the extent of suppression differed in the different soils. Benomyl fungicide and methyl carbamate insecticide had a stimulatory effect on heterotrophic nitrogen fixation in soils under rice roots. Different rice cultivars stimulated strains of Azospirillum to varying extent, and thus did not fix nitrogen to the same extent. It is thus possible that varieties of rice could be selected on the basis of their ability to support non-symbiotic N fixation in their rhizosphere

Seroepidemiology of bluetongue in South Bengal

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Arkendu Halder

2016-01-01

Full Text Available Aim: With the aim of revealing the epidemiological intricacies of bluetongue (BT in the southern part of West Bengal state, the present study was undertaken to assess seroprevalence of BT along with identification of the vector of the disease, i.e., Culicoides midges available in the region in their breeding season with conducive environmental factors, if any. Materials and Methods: A total of 1509 (sheep-504, goat-1005 samples were collected from three different agroclimatic zones of South Bengal viz. new alluvial, red laterite and coastal saline. To detect anti-BT antibodies in the collected serum samples, indirect-enzyme-linked immunosorbent assay (i-ELISA was performed. Culicoides midges were collected from those agro-climatic zones of South Bengal for species identification. The meteorological parameters, viz. temperature (maximum and minimum, rainfall and relative humidity of three agro-climatic zones of South Bengal were analyzed for the months of July to December during 2010-2013. Results: The overall seropositivity was 33.13% and 30.24% in sheep and goat, respectively as assessed by i-ELISA. In South Bengal, the predominant species of Culicoides found were Culicoides schultzei, Culicoides palpifer and Culicoides definitus. Conclusion: Since virus transmitting species of Culicoides midges could be detected in South Bengal, besides high seropositivity in ruminants, the possibility of circulating BT virus in South Bengal is quite imminent.

Safety Assessment of a Hypothetical Near Surface Disposal at PPTN Serpong Site: Near-Field Modeling

International Nuclear Information System (INIS)

Lubis, Erwansyah

2000-01-01

The near field modeling of a hypothetical surface disposal at Serpong site has been performed. Considering a realistic downward water flux of 10 -1 0 m/s through the conditioned waste zone and the concrete barriers, transport of radionuclide by advection and dispersion below the bottom of the repository was calculated using PORFLOW computer code. The result shows that the highest fluxes were observed H-3, Cs-135, Nb-94 and Ni-59, all about 10 4 Bq/a/m 2 . Intermediate fluxes were obtained for Cs-137, I-129 and Co-60. Lowest were due to Ni-63 and C-14. The effect on radionuclide fluxes by having an unsaturated soil of 1.0-m depth below the bottom of the repository also was investigated. The results indicate that the highest fluxes are due to Cs-135, Nb-94 and Ni- 59, approximately 10 4 Bq/a/m 2 . The fluxes owing to H-3 has decreased to 10 -9 Bq/a/m 2 owing to decay. Radionuclides that are not absorbed onto lateritic clay soil, C-14 and I-129 are not decreased in flux. All other radionuclides has significantly smaller fluxes compared to the ones calculated at the bottom of the repository. This indicates that the lateric clay soil at Serpong site plays an important role in retarding and dispersing the radionuclide migration towards the ground water. (author)

Regolith-geology mapping with support vector machine: A case study over weathered Ni-bearing peridotites, New Caledonia

Science.gov (United States)

De Boissieu, Florian; Sevin, Brice; Cudahy, Thomas; Mangeas, Morgan; Chevrel, Stéphane; Ong, Cindy; Rodger, Andrew; Maurizot, Pierre; Laukamp, Carsten; Lau, Ian; Touraivane, Touraivane; Cluzel, Dominique; Despinoy, Marc

2018-02-01

Accurate maps of Earth's geology, especially its regolith, are required for managing the sustainable exploration and development of mineral resources. This paper shows how airborne imaging hyperspectral data collected over weathered peridotite rocks in vegetated, mountainous terrane in New Caledonia were processed using a combination of methods to generate a regolith-geology map that could be used for more efficiently targeting Ni exploration. The image processing combined two usual methods, which are spectral feature extraction and support vector machine (SVM). This rationale being the spectral features extraction can rapidly reduce data complexity by both targeting only the diagnostic mineral absorptions and masking those pixels complicated by vegetation, cloud and deep shade. SVM is a supervised classification method able to generate an optimal non-linear classifier with these features that generalises well even with limited training data. Key minerals targeted are serpentine, which is considered as an indicator for hydrolysed peridotitic rock, and iron oxy-hydroxides (hematite and goethite), which are considered as diagnostic of laterite development. The final classified regolith map was assessed against interpreted regolith field sites, which yielded approximately 70% similarity for all unit types, as well as against a regolith-geology map interpreted using traditional datasets (not hyperspectral imagery). Importantly, the hyperspectral derived mineral map provided much greater detail enabling a more precise understanding of the regolith-geological architecture where there are exposed soils and rocks.

South-East Asian Fortified Stone Walls: Angkor Thom (Cambodia, Ho Citadel (Vietnam and Ratu Boko (Indonesia

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Víctor Lluís Pérez Garcia

2017-02-01

Full Text Available This article aims to analyze three significant examples of defensive walls from South-East Asia made of solid stone blocks (both rock as well as stone-like laterite and provided with different but equivalent functions –a fortified imperial capital-city (Angkor Thom, in Cambodia, a fortified royal citadel (Ho Citadel, in the North of Vietnam and a royal palace with a partly fortified appearance (Ratu Boko, in Java Island, Indonesia–, focusing on their constructive and technical characteristics and establishing parallels between them and their closest counterparts, from China and India. We will see how their design and structure can be closely related to the fortifications of neighbouring empires, as places of origin of their strong cultural influences and, at the same time, we will try to identify the local particularities. We will pay special attention to the form of the fortified enceintes, considering the long tradition of the quadrangular plan in the walls of royal capitals, inspired in the ideal model of Chinese and Indian cities. Our research also make us think that the walls of Ratu Boko, despite their functions as symbolic limits or for retaining the soil, could also have had a defensive purpose, no matter if secondary, or at least they could be used to provide protection to the complex in case of external menace.

Adsorption Mechanisms of Trivalent Gold onto Iron Oxy-Hydroxides: From the Molecular Scale to the Model

International Nuclear Information System (INIS)

Cances, Benjamin; Benedetti, Marc; Farges, Francois; Brown, Gordon E. Jr.

2007-01-01

Gold is a highly valuable metal that can concentrate in iron-rich exogenetic horizons such as laterites. An improved knowledge of the retention mechanisms of gold onto highly reactive soil components such as iron oxy-hydroxides is therefore needed to better understand and predict the geochemical behavior of this element. In this study, we use EXAFS information and titration experiments to provide a realistic thermochemical description of the sorption of trivalent gold onto iron oxy-hydroxides. Analysis of Au LIII-edge XAFS spectra shows that aqueous Au(III) adsorbs from chloride solutions onto goethite surfaces as inner-sphere square-planar complexes (Au(III)(OH,Cl)4), with dominantly OH ligands at pH > 6 and mixed OH/Cl ligands at lower pH values. In combination with these spectroscopic results, Reverse Monte Carlo simulations were used to constraint the possible sorption sites on the surface of goethite. Based on this structural information, we calculated sorption isotherms of Au(III) on Fe oxy-hydroxides surfaces, using the CD-MUSIC (Charge Distribution - MUlti SIte Complexation) model. The various Au(III)-sorbed species were identified as a function of pH, and the results of these EXAFS+CD-MUSIC models are compared with titration experiments. The overall good agreement between the predicted and measured structural models shows the potential of this combined approach to better model sorption processes of transition elements onto highly reactive solid surfaces such as goethite and ferrihydrite

Evaluation of the Addition liquor with high ammonia and Carbon Dioxide contentin the still 208 of the “Comandante Che Guevara” industry (ECG

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María Elena Magaña-Haynes

2015-12-01

Full Text Available Adding fresh liquor through the 5th ring in still 208 of distilling liquor product (liquor obtained as a result of ammonium carbonate leaching of lateritic ore in the “Comandante Che Guevara” industry, were evaluated with the objective of reducing the dissolved nickel content of the effluent there from, as well as to improve the characteristics of the nickel carbonate which is delivered to the calcinations process. For the development of the survey, the same methodology used in 2001 for the test was applied. The results showed that by adding fresh liquor, it is possible to reduce the dissolved nickel content at the exit of the distillation column, so that the need for precipitation is minimized, thereby reducing the consumption of reagents and the and the cost for their acquisition. It was possible to corroborate the relationship between the content of NH3 at the discharge and the nickel dissolved therein appreciating that to achieve these results it is necessary to maintain the ammonia in the discharge between 1,0-1,8 g/L. The carbonate obtained in the column where liquor is added with high CO2 and NH3 reached high values of this last element in its composition and to the extent that increased sulphur content decreased. It was also seen an increase in the size of the coarse carbonates particles, which will influence in a decrease of energy consumption.

Geo-Electrical Exploration for Groundwater within the Premises of University of Ilorin Teaching Hospital, Ilorin, Kwara State, Nigeria

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A. K. Olawuyi

2012-12-01

Full Text Available Schlumberger Vertical Electrical Soundings for groundwater search within the premises of University of Ilorin Teaching Hospital (UITH situated along Ilorin- Jebba road in Kwara State, were carried out with a view to establishing the different subsurface geoelectric layers, the aquifer units and their hydrogeologic properties. Data were collected from 12 VES stations over an area of about 500 m x 650 m. From the quantitative interpretation of the data collected, using the usual method of curve matching with the Orellana-Mooney Master curves and 1-D forward modeling with WinResist 1.0 version software, four Hthologic units were identified. These include: the topsoil, the lateritic layer, the weathered layer/fractured layer and the fresh basement. The weathered and fractured basement constitutes the main aquifer units. The 2-D resistivity structure has elicited 2 lobes of low resistivity which constitutes the prospective zone for water in the area. The first lobe exists below stations 3 and 4 at about 5-15 m depth, with resistivity between 80- 147 ohm-m and over 300m wide, while the other lobe of low resistivity which also signifies a possible borehole location exists below stations 7,8 and 9 at a depth of about 2-14 m, with resistivity between 141-200 ohm-m and over 550 m wide. The study concluded that the area investigated contains two lobes of low resistivity which could be explored for water supply.

Studies of mineralogy and geochemistry of Rare Earth Elements in permo-Triassic Bauxite deposit, Northeast of Bukan, North West of Iran

International Nuclear Information System (INIS)

Abedini, A.; Calagari, A. A.; Hadjalilu, B.; Jahangiri, A.

2008-01-01

Bauxite deposit of Permo-Triassic age in northeast of Bukan was developed stratiformly along the boundary between Ruteh and Elika formations, and includes four distinct rock units. This deposit was affected by tectonic and morphological processes. Mineralogical and geochemical investigations showed that during weathering processes, two mechanisms of ferrugenization and deferrugenization played crucial role in formation of minerals such as Diaspora, boehmite, hematite, goethite, kaolinite, pyrophyllite, clinochlore, illite, montmorillonite, anatase, rutile, albite, sanidine, quartz, and calcite in this deposit. By taking notice of field evidence and of mineralogical and geochemical data, the basalts (whose remnants are still present along the contact of this deposit with carbonate bedrock) are the potential parent rock of this deposit. The distribution pattern of rare earth elements (normalized to chondrite and basaltic parent rock) along with anomaly variations of Eu, Ce, and (La/Yb) N indicates differentiation of LREEs from HREEs during bauxitization processes. Further geochemical considerations indicate that the concentrations of LREEs were occurred by hematite, goethite, manganese oxides, cerianite, and secondary phosphates (rhabdophane, vitusite, gorceixite, monazite) and of HREEs by clay minerals; rutile, anatase, zircon, euxenite, and fergusonite. Incorporation of the results obtained from mineralogical and geochemical investigations suggests that in addition to factors such as p H of weathering solutions, ionic potential, composition of the parent rock, and fixation by residual minerals, adsorption processes also played crucial role in enrichment of rare earth elements during moderate to intense lateritization in the study area

Soil micronutrients and its uptake by rice plant. Part of a coordinated programme on isotope-aided micronutrient studies in rice production with special reference to zinc deficiencies

International Nuclear Information System (INIS)

Kim, T.S.

1980-02-01

A series of field and greenhouse experiments with flooded rice was carried out on contrasting soil types of Korea to study the zinc status of soils, evaluate the chemical methods for extracting zinc from soils in terms of ability to identify zinc deficiency, perform 65 Zn-aided experiments including the residual effects of zinc fertilizers to evaluate the efficiency of zinc sources and methods of zinc application to rice, and associated studies on factors affecting zinc nutrition in rice such as effect of organic matter and chelates. The results show that i) 0.05 N HCl solution for extracting available zinc in soil was effective to separating the soils which require zinc fertilizer application. The proposed zinc value to identify is 2.4 ppm. Among rice soils surveyed, the red-yellow podsolic soil derived from basalt, the reddish-brown lateritic soil of calcareous material and newly reclaimed saline soils were shown to be below this limit; ii) 5 kg Zn/ha as zinc sulphate introduced the highest response in terms of % Zndff, total zinc yield in rice plant, and the fertilizer zinc use efficiency. Applying higher zinc amounts, in case of 20 kg Zn/ha, retarded nitrogen uptake by the plant and as a result the rice grain yield was decreased; iii) Significant yields increases due to the residual effects of zinc fertilizers were obtained on the second and third crops; iv) On the zinc-deficient calcareous soil the use of chelated zinc sources is recommended

New geological and tectonic map of Paleoproterozoic basement in western Burkina Faso: integrated interpretation of airborne geophysical and field data

Science.gov (United States)

Metelka, Vaclav; Baratoux, Lenka; Jessell, Mark; Naba, Seta

2010-05-01

The recent acquisition of regional scale airborne datasets over most of the West African craton sparked off a number of studies concentrating on their litho-tectonic interpretation. In such polydeformed terrains, where outcrop is very sparse or virtually nonexistent due to the presence of thick lateritic cover, geophysics and specifically geomagnetic surveying provide a wealth of information that facilitates the deciphering of regional litho-structural hierarchies. A revised geological and tectonic map of the Houndé and Boromo greenstone belts was derived by interpretation of aeromagnetic and gamma-ray spectrometric data constrained by field observations where available. Medium resolution geophysical data gridded at 250 meters acquired during the SYSMIN project served as a basis for the interpretation. This dataset was integrated with the SRTM digital elevation model and over 600 field observations. Furthermore, the BRGM/BUMIGEB SYSMIN project outcrops database (Castaing et al., 2003) as well as older outcrop maps, maintained by BUMIGEB, were used. Locally, outcrop maps and high resolution geophysics provided by mining companies (Orezone, SEMAFO, Volta Resources, Wega Mining) were employed. 2-D geophysical inversion modeling in GM-sys software using the ground gravity and airborne magnetic data was applied to three selected E-W profiles. Principal component analysis (PCA) of magnetic and radiometric data was a powerful tool for distinguishing different lithological units, in particular tholeiitic suites of basalts and gabbros and various volcano-sedimentary units. Some of the granite pluton limits can be traced as well using the PCA; however thick lateritic cover substantially hinders precise mapping. Magnetic data used on its own gave better results not only for granite limits but also for determining internal structures such as shear zones and concentric compositional zoning. Several major N-S to NNE-SSW oriented shear zones, representing most probably deep

Responses and Remediating Effects of Pennisetum hydridum to Application of Heavy-Metals-Contaminated Chicken Manures and Sewage Sludges

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WANG Xi-na

2015-10-01

Full Text Available Pennisetum hydridum is a rapid growth, large biomass and multi-stress resistant plant. A pot experiment was carried out to investigate the bioremediation effects of P. hydridum by 2 kg heavy metal (Cd, Cu, Pb, and Zn contaminated chicken manure or sewage sludge mixing with 18 kg of lateritic red soil. The growth and heavy metal uptake of P. hydridum were measured in order to assess the phytoremediation potential. Results showed that P. hydridum growed well in all treatments and the best appeared in chicken manure. The biomass of plant in treatments with chicken manure, sewage sludge, and the control was 736.56±29.21, 499.99±32.01 g·pot-1, and 466.89±37.08 g·pot-1, respectively. The heavy metals in the soils were reduced significantly at the 200 d after planting P. hydridum in fall. The removing percentage of total Zn, Cu, Pb, and Cd in soil was 1.90%~4.52%, 3.96%~5.72%, 0.53%~1.24% and 10.34%~17.14% respectively. The best effect of removing Zn, Cd and Pb appeared in chicken manure treatment was 89.74, 0.68 mg and 19.18 mg. The best effect of removing Cu appeared in sludge treatment was 16.84 mg. The results indicated that P. hydridum could be used for removement of the heavy metals from the heavy metal contaminated soils which could be considered as an potential plant for bioremediation of heavy metals.

Alteration mineral mapping for iron prospecting using ETM+ data, Tonkolili iron field, northern Sierra Leone

Science.gov (United States)

Mansaray, Lamin R.; Liu, Lei; Zhou, Jun; Ma, Zhimin

2013-10-01

The Tonkolili iron field in northern Sierra Leone has the largest known iron ore deposit in Africa. It occurs in a greenstone belt in an Achaean granitic basement. This study focused mainly on mapping areas with iron-oxide and hydroxyl bearing minerals, and identifying potential areas for haematite mineralization and banded iron formations (BIFs) in Tonkolili. The predominant mineral assemblage at the surface (laterite duricrust) of this iron field is haematitegoethite- limonite ±magnetite. The mineralization occurs in quartzitic banded ironstones, layered amphibolites, granites, schists and hornblendites. In this study, Crosta techniques were applied on Enhanced Thematic Mapper (ETM+) data to enhance areas with alteration minerals and target potential areas of haematite and BIF units in the Tonkolili iron field. Synthetic analysis shows that alteration zones mapped herein are consistent with the already discovered magnetite BIFs in Tonkolili. Based on the overlaps of the simplified geological map and the remote sensing-based alteration mineral maps obtained in this study, three new haematite prospects were inferred within, and one new haematite prospect was inferred outside the tenement boundary of the Tonkolili exploration license. As the primary iron mineral in Tonkolili is magnetite, the study concludes that, these haematite prospects could also be underlain by magnetite BIFs. This study also concludes that, the application of Crosta techniques on ETM+ data is effective not only in mapping iron-oxide and hydroxyl alterations but can also provide a basis for inferring areas of potential iron resources in Algoma-type banded iron formations (BIFs), such as those in the Tonkolili field.

Classifying zones of suitability for manual drilling using textural and hydraulic parameters of shallow aquifers: a case study in northwestern Senegal

Science.gov (United States)

Fussi, F. Fabio; Fumagalli, Letizia; Fava, Francesco; Di Mauro, Biagio; Kane, Cheik Hamidou; Niang, Magatte; Wade, Souleye; Hamidou, Barry; Colombo, Roberto; Bonomi, Tullia

2017-12-01

A method is proposed that uses analysis of borehole stratigraphic logs for the characterization of shallow aquifers and for the assessment of areas suitable for manual drilling. The model is based on available borehole-log parameters: depth to hard rock, depth to water, thickness of laterite and hydraulic transmissivity of the shallow aquifer. The model is applied to a study area in northwestern Senegal. A dataset of boreholes logs has been processed using a software package (TANGAFRIC) developed during the research. After a manual procedure to assign a standard category describing the lithological characteristics, the next step is the automated extraction of different textural parameters and the estimation of hydraulic conductivity using reference values available in the literature. The hydraulic conductivity values estimated from stratigraphic data have been partially validated, by comparing them with measured values from a series of pumping tests carried out in large-diameter wells. The results show that this method is able to produce a reliable interpretation of the shallow hydrogeological context using information generally available in the region. The research contributes to improving the identification of areas where conditions are suitable for manual drilling. This is achieved by applying the described method, based on a structured and semi-quantitative approach, to classify the zones of suitability for given manual drilling techniques using data available in most African countries. Ultimately, this work will support proposed international programs aimed at promoting low-cost water supply in Africa and enhancing access to safe drinking water for the population.

Effect of alteration processes on the distribution of radionuclides in uraniferous sedimentary rocks and their environmental impact, southwestern Sinai, Egypt

International Nuclear Information System (INIS)

El Aassy, I.E.; El Galy, M.M.; El Feky, M.G.; Ibrahim, E.M.; Nada, A.A.; Abd El Maksoud, T.M.; Talaat, S.M.

2011-01-01

The contents of natural radionuclides in various types of sedimentary rocks in Um Bogma Formation and base of El Hashash Formation were determined by gamma-ray spectrometry. Three types of lower Carboniferous sedimentary rocks were investigated; sandstone (El Hashash Formation), dolostone and argillaceous sediments (Um Bogma Formation). The alteration processes are dolomitization, dedolomitization, karstification and lateritization. The specific radioactivity of 238 U, 226 Ra, 232 Th and 40 K determined in different samples, indicate that 238 U and its decay products contribute primarily to the high natural radioactivity of rocks. The maximum concentration of 238 U reached up to 2129.36 ppm in argillaceous sediments. The average concentrations of determined radionuclides ( 238 U, 226 Ra, 232 Th and 40 K) are 8.34 ppm, 7.88 ppm, 4.68 ppm and 0.3%, respectively in sandstone. In dolostones the average concentrations are 418.69 ppm, 808.75 ppm, 3.14 ppm and 0.29%, respectively. For argillaceous sediments are 276.88 ppm, 419.49 ppm, 11.47 ppm and 0.93%, respectively. The 238 U/ 226 Ra ratio in sandstone ranges between 0.89 and 1.25, while in dolostones and argillaceous sediments are 0.27-2.63 and 0.27-1.83, respectively. These variations in the concentrations of radioelements and their ratios are due to the action of the alteration processes affected these different sedimentary rocks in different times. Environmentally, the Raeq in dolostones and argillaceous sediments exceeds the permitted limits, while in the sandstone samples; it is within the permissible levels. (author)

A review of nickel toxicity to marine and estuarine tropical biota with particular reference to the South East Asian and Melanesian region.

Science.gov (United States)

Gissi, Francesca; Stauber, Jennifer L; Binet, Monique T; Golding, Lisa A; Adams, Merrin S; Schlekat, Christian E; Garman, Emily R; Jolley, Dianne F

2016-11-01

The South East Asian Melanesian (SEAM) region contains the world's largest deposits of nickel lateritic ores. Environmental impacts may occur if mining operations are not adequately managed. Effects data for tropical ecosystems are required to assess risks of contaminant exposure and to derive water quality guidelines (WQG) to manage these risks. Currently, risk assessment tools and WQGs for the tropics are limited due to the sparse research on how contaminants impact tropical biota. As part of a larger project to develop appropriate risk assessment tools to ensure sustainable nickel production in SEAM, nickel effects data were required. The aim of this review was to compile data on the effects of nickel on tropical marine, estuarine, pelagic and benthic species, with a particular focus on SEAM. There were limited high quality chronic nickel toxicity data for tropical marine species, and even fewer for those relevant to SEAM. Of the data available, the most sensitive SEAM species to nickel were a sea urchin, copepod and anemone. There is a significant lack of high quality chronic data for several ecologically important taxonomic groups including cnidarians, molluscs, crustaceans, echinoderms, macroalgae and fish. No high quality chronic nickel toxicity data were available for estuarine waters or marine and estuarine sediments. The very sparse toxicity data for tropical species limits our ability to conduct robust ecological risk assessment and may require additional data generation or read-across from similar species in other databases (e.g. temperate) to fill data gaps. Recommendations on testing priorities to fill these data gaps are presented. Copyright © 2016 Elsevier Ltd. All rights reserved.

Mineral potential for nickel, copper, platinum group elements(PGE), and chromium deposits hosted in ultramafic rocks in the Islamic Republic of Mauritania (phase V, deliverable 67): Chapter G in Second projet de renforcement institutionnel du secteur minier de la République Islamique de Mauritanie (PRISM-II)

Science.gov (United States)

Taylor, Cliff D.; Marsh, Erin; Anderson, Eric D.

2015-01-01

PRISM-I summary documents mention the presence of mafic-ultramafic igneous intrusive rocks in several areas of Mauritania and a number of chromium (Cr) and copper-nickel (Cu-Ni (±Co, Au)) occurrences associated with them. Permissive geologic settings generally include greenstone belts of any age, layered mafic-ultramafic and unlayered gabbro-anorthosite intrusive complexes in cratonic settings, ophiolite complexes, flood basalt provinces, and fluid-rich shear zones cutting accumulations of mafic-ultramafic rocks. Regions of Mauritania having these characteristics that are discussed in PRISM-I texts include the Mesoarchean greenstone belts of the TasiastTijirit terrane in the southwestern Rgueïbat Shield, two separate layered ultramafic complexes in the Amsaga Complex west of Atar, serpentinized metadunites in Mesoarchean rocks of the Rgueïbat Shield in the Zednes map sheet, several lateritized annular mafic-ultramafic complexes in the Paleoproterozoic northwestern portion of the Rgueïbat Shield, and the serpentinized ophiolitic segments of the Gorgol Noir Complex in the axial portion of the southern Mauritanides. Bureau de Recherches Géologiques et Minières (BRGM) work in the “Extreme Sud” zone also suggests that small copper occurrences associated with the extensive Jurassic microgabbroic intrusive rocks in the Taoudeni Basin of southeastern Mauritania could have potential for magmatic Cu-Ni (PGE, Co, Au) sulfide mineralization. Similarly, Jurassic mafic intrusive rocks in the northeastern Taoudeni Basin may be permissive. Known magmatic Cu-Ni deposits of these types in Mauritania are few in number and some uncertainty exists as to the nature of several of the more important ones.

Radiotracer study of the fate and persistence of organic fungicides used as seed dressing on grain. Part of a coordinated programme of isotopic tracer aided studies of foreign chemical residues in food

International Nuclear Information System (INIS)

Raghu, K.

1976-12-01

Radiotracer-aided studies were made of the fate and persistence of Thiram, used as a seed dresser and Ziram used as a foliar spray and their effects on soil fertility and plant growth. Thiram applied as a seed dresser had no inhibitory effect on (a) seedling height and rhizosphere microflora of barley, (b) soil microflora, (c) nodulation of cowpea plants. The uptake of 35 S radioactivity at 20-day stage was 0.3% of the total applied as 35 S thiram. Thiram as such was not present in barley or maize plants at any of the growth stages up to grain formulation but was converted into DDC-glucoside, DDC-alamine, fungicide X and TTCA. The quantity of these decreased in barley and maize with time and were in negligible amounts at grain stage. The sulphur from thiram found its way into sulphur-containing metabolites like protein, amino acids, sulfolipids, etc. Ziram, a foliar spray fungicide was also converted into DDC-conjugates and the amounts of residue were negligible at harvest time both in rice and groundnut. Thiram degraded more rapidly in unsterilized soils than in sterilized soil, thus indicating biodegradation. The fungicide is more persistent in sandy than in laterite and alluvial soils. Microbial degradation of thiram was shown by comparing persistence of 35 S thiram in sterilized and unsterilized soils. A Pseudomonas sp. isolated from soil was capable of degrading thiram and ziram and DDC-aminobutyric acid was the major polar metabolite. The appearance of similar degradation products with these dialkyl dithiocarbamates indicated that they have some common metabolic pathway

Material and energy flows in rotary kiln-electric furnace smelting of ferronickel alloy with energy saving

International Nuclear Information System (INIS)

Liu, Peng; Li, Baokuan; Cheung, Sherman C.P.; Wu, Wenyuan

2016-01-01

Highlights: • Establish the synergy relationship of material and energy in key RKEF processes. • Develop an analysis model to study energy saving with internal cycling of energy. • Analyze material and energy flow parameters and assess its associated synergy effect. • A methodology to evaluate the synergy and design indices of RKEF processes. - Abstract: An energy saving strategy with two energy saving measures has been proposed for reducing energy loss in the rotary kiln-electric furnace (RKEF) for the smelting of ferronickel alloy. One of the measures is to recover the waste heat of exhaust gas from the rotary kiln for preheating and dehydrating the wet laterite ores in the rotary dryer. Another measure is to recycle the furnace gas from the electric furnace into the rotary kiln as fuel. Based on the mass conservation and energy conservation laws, an analysis model of material and energy flows has been developed to understand the potential energy saving with the internal cycling of material and energy in the RKEF process. The analysis model not only considers the energy efficiency but also assess the synergy degree of system. Furthermore, the model also predicts the ratio of raw materials and the energy flow distribution to investigate residual heat and energy and analyze the effects of nickel content on energy flow. Finally, the evaluation methodology of synergy and the technic indices are also presented. Through the investigation of the synergy effect, the performance of the RKEF process can be evaluated and quantified for performance optimization in future.

Absorption and translocation of 32P through root feeding by root (Wilt) affected coconut palms

International Nuclear Information System (INIS)

Beena George, S.; Moossa, P.P.; Sureshkumar, P.

2017-01-01

An investigation was carried out during 2015-16 to study the absorption and translocation of 32 P by root (wilt) affected coconut palms through root feeding in the Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara. Root (wilt) is one of the major diseases affecting coconut production in India. Etiology of the disease has been examined from several angles and it was found that nutrition imbalance in association with root (wilt) and it remains so even if integrated nutrient management practices are applied to diseased palms. Absorption and translocation of nutrients in three different types of coconut palms (healthy, apparently healthy and diseased palms) were studied using radioactive phosphorusin laterite soil. Ten morphologically uniform palms of same age were selected from each type of palms. Four active young roots were excavated from each palm and 32 P was applied by root feeding and index leaves were radio assayed for 32 P count at 24 hours, 15 and 30 days after application. The results revealed that healthy palms recorded significantly higher count rate(581 to 25158.66 cpm g -1 ) with root feeding compared to diseased palms(263 to 1068.38 cpm g - 1 ). From the present study it was clear that root (wilt) disease cannot be managed by soil application of nutrients because roots of the diseased palms are not able to translocate these nutrients. Since nutrient imbalance was one of the major problems noticed in root (wilt) affected palms, further study is required to find out proper method of nutrient application. (author)

NW Oregon radon potential based on soil radionuclides

International Nuclear Information System (INIS)

Ashbaugh, S.G.; Burns, S.F.

1993-01-01

Analysis of soil by gamma spectroscopy for Bi-214 (Ra-226) suggests low to moderate radon potentials for northwest Oregon in areas with low to moderate soil permeabilities. Very low radon potential zones (0.2 to 0.7 pCi/g) comprise 58% of the study area. These zones are frequently associated with soils developed from undifferentiated basalts and andesites of the Cascade Range, and basalts and undifferentiated mafic intrusives of the Coast Range. Low radon potential zones (0.7 to 1.2 pCi/g) comprise 28% of the study area. These zones are generally associated with Missoula Flood sediments, pre-Holocene loess in the Portland area, and Eocene/Oligocene marine sediments low in mica and/or tuff along the foothills of the Willamette Valley. Moderate radon potential zones (1.2 to 3.0 pCi/g) comprise 14% of the study area. These zones are often associated with the lateritic soils derived from Columbia River Basalts and Eocene/Oligocene marine sediments high in mica and/or tuff along the western edges of the Willamette Valley. A closer examination of soils in the Portland and Salem areas shows that: (1) Bi-214/K-40 ratios increase from 0.07 to 0.35 with respect to solid development, indicating K-40 to be preferentially leached over Ra-226; (2) clay development within B-horizons does not reflect a significant increase in Ra-226 mobility; and (3) elevated indoor radon within the Portland and Salem areas can be attributed to high soil permeabilities rather than soil chemistry

Short-lived U and Th isotope distribution in a tropical laterite derived from granite (Pitinga river basin, Amazonia, Brazil): Application to assessment of weathering rate

Science.gov (United States)

Mathieu, D.; Bernat, M.; Nahon, D.

1995-12-01

We have analyzed samples of a 15 m thick profile weathered from the Madeira granite, located in the Pitinga basin river, north of Manaus, in the state of Amazonia, Brazil. This profile consists essentially of a yellow-red saprolite covered by a soil. U and Th concentrations are particularly high in the granite (20 and 80 μg/g respectively). Normalized element to Th concentrations indicate that Th is most resistant to chemical weathering, except to some extent in the top soil. Higher concentrations in the saprolite compared to the granite comprise a relative enrichment, resulting from a loss of mass. The saprolites are initially generated by a descending weathering front which alters the granite to a yellow-red saprolite, a second front, close to the top, turns the saprolite into a soil. Weathering has led to leaching of U. The 234U/ 238U and 230Th/ 238U isotopic ratios are in radioactive disequilibrium. Numerous nodules are present and apparently started to form at the base of the saprolite. These nodules achieve more developed form during their relative ascent until they are reached by the descending top front where they undergo dissolution. The Th and Pb are concentrated in the nodules close to the top front. The U, being more mobile, is strongly leached by the first front, and most of the remainder, freed by the second, engages in a descending flux which supplies the underlying saprolite. Using the data an attempt is made to model the isotopic distribution in the profile. We conclude that the first front has descended at a rate of 5 cm/1000 yt, and that the time needed to create the saprolite must have been around 300,000 yr.

Geochemical characterization of the largest upland lake of the Brazilian Amazonia: Impact of provenance and processes

Science.gov (United States)

Sahoo, Prafulla Kumar; Guimarães, José Tasso Felix; Souza-Filho, Pedro Walfir Martins; da Silva, Marcio Sousa; Nascimento, Wilson, Júnior; Powell, Mike A.; Reis, Luiza Santos; Pessenda, Luiz Carlos Ruiz; Rodrigues, Tarcísio Magevski; da Silva, Delmo Fonseca; Costa, Vladimir Eliodoro

2017-12-01

Lake Três Irmãs (LTI), the largest upland lake in the Brazilian Amazonia, located in Serra dos Carajás, was characterized using multi-elemental and isotope geochemistry (δ13C and δ15N) to understand the significance of organic and inorganic sources, weathering and sedimentary processes on the distribution of elements in lake bottom (surficial) sediments. Carbon and nitrogen isotopes from sedimentary organic matter suggest C3 terrestrial plants (forests > canga vegetation), macrophytes and freshwater DOC as the main sources. Sediments are depleted in most of the major oxides (except Fe2O3 and P2O5) when compared to upper continental crust (UCC) and their spatial distribution is highly influenced by catchment lithology. Principal Component Analysis revealed that most of the trace elements (Ba, Sr, Rb, Sc, Th, U, Zr, Hf, Nb, Y, V, Cr, Ga, Co, Ni) and REEs are closely correlated with Al and Ti (PC1; Group-1), so their redistribution is less influenced by post-depositional process. This is due to their relative immobility and being hosted by Al-bearing minerals during laterization. High Chemical Index of Alteration (CIA), Mafic Index of Alteration (MIA) and Index of Laterization (IOL) values indicate intense chemical weathering at source areas, but the weathering transformation was better quantified by IOL. A-CN-K plot along with elemental ratios (Al/K, Ti/K, Ti/Zr, La/Al, Cr/Th, Co/Th, La/Sm, La/Gd, Zr/Y, and Eu/Eu*) as well as chondrite-normalized REE patterns show that the detritic sediments are mainly sourced from ferruginous laterites and soils in the catchment, which may have characteristics similar to mafic rocks.

Iso-Naakkima, a circular structure filled with Neoproterozoic sediments, Pieksämäki, southeastern Finland

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Elo, S.

1993-06-01

Full Text Available A circular Bouguer gravity anomaly with a minimum of -4.0 mGal and halfamplitude width of 2 km was recognized at Lake Iso-Naakkima (62°11'N, 27°09'E, southeastern Finland. The gravity low is associated with subdued aeromagnetic signature and notable airborne and ground electromagnetic anomalies that indicate low bedrock resistivity. The drilling record beneath the recent (Quaternary glacial sediments, 25-40 m thick, reveals a 100 m thick sequence of unmetamorphosed shale, siltstone, quartz sandstone, kaolinitic clay and conglomeratic sandstone that rest on a weathered mica gneiss basement. The upward fining sequence is characterized by red colour, high kaolinite content, and tilted, distorted and brecciated beds. According to the geophysical modelling the diameter of the whole basin is 3 km and that of the sedimentary rocks 2 km, and the depth is 160 m. Shock lamellas in quartz clasts of the basal conglomeratic sandstone, almost omnipresent kink banding in micas of the rocks beneath the basin floor and the occurrence of polymictic dike breccia in the underlying mica gneiss suggest shock metamorphism. It was concluded that the basin originated by a meteorite impact. However, the impact-generated rocks were subsequently eroded before the sedimentation and only minor marks of shock metamorphism were preserved. Lateritic weathering took place prior to deposition of the sediments. Quartz sandstone and siltstone are interpreted as fluvial deposits and the thinly laminated shales as transgressi ve lacustrine or lagoonal deposits. The microfossil assemblage in the shale includes sphaeromorphs of acritarchs from Late Riphean (Neoproterozoic. Postdepositional subsidence of the Iso-Naakkima basin, shown by tilted sediments, preserved the sequence from further erosion.

Applying persistent scatterer interferometry for surface displacement mapping in the Azul open pit manganese mine (Amazon region) with TerraSAR-X StripMap data

Science.gov (United States)

Athayde Pinto, Carolina de; Paradella, Waldir Renato; Mura, José Claudio; Gama, Fabio Furlan; Ribeiro dos Santos, Athos; Silva, Guilherme Gregório; Hartwig, Marcos Eduardo

2015-01-01

The Azul mining complex, located in the Carajás Mineral Province, Amazon region, encompasses the most important manganese mine in Brazil. Vale S.A. company operates three simultaneous open pit excavations (mines 1, 2, and 3) in the area, which are conducted on rock alteration products of low geomechanical quality related to sandstones, siltstones, and a lateritic cover. In order to monitor ground deformation, 33 TerraSAR-X (TSX-1) StripMap images covering the period of March 2012-April 2013 were used in the investigation. An advanced differential interferometric synthetic aperture radar (A-DInSAR) approach based on persistent scatterer interferometry (PSI) using an interferometric point target analysis algorithm was applied, and the results showed that most of the area was considered stable during the time span of the synthetic aperture radar acquisitions. However, persistent scatterers (PS) with high deformation rates were mapped over a waste pile, probably related to settlements, and also along the north flank of mine 1, indicative of cut slope movements toward the center of the pit. A spatial relationship of geological structures with PS was observed for this sector of the mine, given by PS showing deformation rates concentrated along a structural corridor with faults, fractures, and folds related to the Carajás fault system. Though only ground-based radar measurements for wall benches of mine 1 were available for a short time period of the TSX-1 coverage, the PS movement patterns showed concordance with geotechnical field measurements. The investigation emphasized the important role that satellite-based A-DInSAR can play for deformation monitoring and risk assessment in this kind of mining area.

Isotope tracer-aided studies on the date and significance of insecticides used for the control of rice pests under conditions of Indian agriculture. Coordinate programme on isotopic-tracer-aided studies on the origin and fate of foreign chemical residues in the agricultural environment

International Nuclear Information System (INIS)

Sethunathan, N.

1976-01-01

Radiotracer-aided studies were made of the fate of insecticides: parathion, benzenehexachloride (BHC) and endrin in rice soils under flooded conditions and the effect of a fungicide benomyl on heterotrophic nitrification. BHC, known for its stability in non-flooded soils and other aerobic environments, decomposed rapidly in microbially-active flooded soils, capable of obtaining Eh of -40 to -100 mV. Moreover the addition of rice straw (a common cultural practice) further accelerated the Eh drop due to enhanced microbial activity and, thereby, BHC degradation. Substantial loss of gamma-BHC also occurred by volatilization from the standing water of flooded soils. The fate of endrin was studied in 8 rice-flooded soils. Endrin decomposed rapidly in most soils, except in a sandy one. Endrin was converted to 6 metabolites in non-sterile samples of laterite, alluvial and pokkali soils as compared to 3 compounds in sterile samples indicating microbial participation. In sandy soils also only 3 compounds were detected and in kari soil 4. The degradation of parathion in flooded soils proceeds by nitrogroup reduction to amino-parathion and by hydrolysis of the P-O-C linkage to P-nitrophenol and diethylthiophosphoric acid. Microorganisms, Penicillium waksmani Zoleski, Pseudomonas sp. and Bacillus sp. are involved in both reactions. Organic sources inhibited the parathion hydrolysis but it is unlikely to cause any residue hazards since at the same time nitrogroup reduction is enhanced. Applications of benomyl to the simulated oxidized zone of flooded soils favoured heterotrophic nitrification due to stimulating the proliferation of heterotrophic nitrifying bacteria. This may pose an indirect environmental pollution hazard in addition to the direct toxicity of the fungicide

SEDIMENTOLOGICAL CHARACTERIZATION OF THE PEDOLOGICAL COVER OF CAMAÇARI ECOLOGICAL RESERVATION, CABO DE SANTO AGOSTINHO, PE, NORTHEASTERN BRAZIL

Directory of Open Access Journals (Sweden)

Danielle Gomes da Silva

2005-05-01

Full Text Available This paper deals with the issues of environmental impacts derived from the continuousprocess of metropolitan growth, and aims at identifying and analysing the erosive processesoccurring in an area that has been legally designated as an environmental reservation,therefore said to be of strict permanent preservation. This research is focused on theunderstanding of causal relationships that unleash events of environmental disequilibrium,following the illegal systematic removal of the regolith for providing building materials tolocal civil construction entrepreneurs. It was possible to demonstrate the links between thespatial distribution of superficial materials (soils, sediments and regolith and the level ofstability of distinct geomorphic units, through the use of a morphostratigraphic approach. Thearea portrays a dissected hilly topography, lying within the limits of “Recife MetropolitanArea”, and therefore suffering the consequence of rapid changes in land use, epitomized bythe extensive removal of natural vegetation and exploitation of its deeply lateritized regolith,in spite of being protected by State laws. Deforestation allied to the removal of the deeplyweathered regolith has caused a rearrangement of the area’s morphodynamic units (Tricart,m1977, as shown by both field and lab-work. However, it was found that the diversity of thepedological cover in the area, as a dynamic response of the lithology to the east coasttradewinds tropical climate, commands the distribution of superficial processes, favoring theocurrence of mass movements, intense linear erosion, damming of superficial waterflow,reworking of sub-recent Aeolian sediments and building of coalescing alluvial fans. Finallythe research threw light on the understanding of the linkages between rates ofgemorphological dynamics and soil cover in a costal humid tropical environment.

A magnetic survey of mineral resources in northeastern Cuba

Energy Technology Data Exchange (ETDEWEB)

Batista Rodriguez, Jose Alberto [Instituto Superior Minero Metalurgico de Moa (Cuba)

2006-01-15

Interpretation of the aeromagnetic survey of northeastern Cuba at scale 1 50 000 is presented. Mainly ophiolitic rocks are characterized by a high magnetic response. The aeromagnetic data was reduced to the pole and the horizontal and vertical gradients, as well as the upward continuation were calculated. To define areas of serpentinized ultrabasic rocks at surface and depth, the magnetic field transformations were interpreted. We discuss lateral extension of outcrops, thickness variation of the ophiolitic rocks, basement extension and fault zones. Hydrothermal alterations indicate associated precious metal secondary mineralization. Operations are planned to limit damage to mining by siliceous material in Fe+Ni laterites. [Spanish] Cuba, en la cual afloran fundamentalmente rocas ofioliticas caracterizadas por un alto grado de magnetizacion. Los datos aeromagneticos fueron reducidos al polo y luego se realizaron los calculos de gradientes horizontales y verticales y la continuacion analitica ascendente. A partir de los resultados de estas transformaciones se delimitaron zonas donde predominan las rocas ultrabasicas serpentinizadas tanto en superficie como en profundidad, definiendose la extension lateral de estas rocas por debajo de las rocas que afloran en superficie. Tambien se estimaron las variaciones de los espesores de las rocas ofioliticas, el basamento de las rocas que afloran, la presencia de estructuras disyuntivas, y se proponen nuevas estructuras de este tipo. Por ultimo se delimitan las zonas de alteracion hidrotermal, lo cual posee gran importancia, ya que con las mismas se pueden vincular mineralizaciones de metales preciosos. Ademas, su delimitacion en depositos lateriticos permite orientar los trabajos de explotacion minera, teniendo en cuenta el dano que causa al proceso metalurgico la presencia de material silicio en las lateritas Fe+Ni.

Internal dose assessment of 238U contaminated soils based on in-vitro gastrointestinal protocol

Science.gov (United States)

Perama, Yasmin Mohd Idris; Rashid, Nur Shahidah Abdul; Majid, Amran Ab.; Siong, Khoo Kok

2017-01-01

Human exposure to natural radioactive uranium has been a great interest as more industrial rapidly growing contributes to radiation risks. The aim of this case study was to determine the internal dose in humans incorporated with ingestion of 238U contaminated soils. A gastrointestinal analogue test was employed to simulate the human digestive tract. In-vitro approach via German DIN 19738 model was developed in order to estimate the internal exposure of 238U due to ingestion of different types of soils. Synthetic gastrointestinal fluids assay via in-vitro method were produced to determine the concentration of 238U in various soils using ICP-MS. Based on the results, concentration of 238U in BRIS, laterite, peat and alluvium soils were in ranged between (0.0061 ± 0.0057 - 0.0488 ± 0.0148) ppm and (0.0005 ± 0.0004 - 0.0046 ± 0.0007) ppm in gastric and gastrointestinal phase respectively. Types of soil compositions and pH medium were some of the factors that influence mobilization and solubility of 238U contaminanted soil into the digestive juices that resembles human gastrointestinal tract. For the purpose of internal dose assessment, the committed efective dose from 238U intake in soils ranged between 1.237 × 10-11 - 9.8993 × 10-11 Sv y-1 for gastric phase and 1.0184 × 10-12 - 9.3294 × 10-12 Sv y-1 for gastric-intestinal phase. The internal dose measurements from this study were much lower from the recommended values. Hence, ingestion of 238U contaminated soils would not be expected to pose major health risk to humans.

Effect of the application of ultrasonic waves on the leaching of nickel ore

International Nuclear Information System (INIS)

Reyes Padilla, Osniel; Castellanos Suarez, Jose; Hernandez Martinez, A. Naida; Cortes Miranda, Maritza; Abraham Islas, Osvel; Cardenas Merella, Rodnie; Trujillo, Maria Elena; Nicot, Yarisleydis; Calzada, Lidia; Sanabria de la Torre, Antonio; Echaide Hernandez, Marcos Julio

2016-01-01

The use of the ultrasonic waves (OU) he/she has been successful in some fields like: the medicine, in catalysts, treatments of foods and in the chemical procedures of laboratory. The applications of OU in the mining are not very well-known and it is not reported in detail in the literature. In the CIPIMM they have been carried out some test in the laboratory with positive results, for what the studies of this technique are continued. The objective of this work was to evaluate in a preliminary phase the application of ultrasonic waves in the process of lixiviation of nickel minerals. The prepared pulps with the mineral were treated in an ultrasonic bathroom at laboratory level. In the process of atmospheric lixiviation with H 2 SO 4 , the application of OU produced an increment in the nickel breakup between a 2 and 5%. The kinetics of breakup of Co was quicker than that of the nickel. The use of OU doesn't increase in a significant way the breakup of the iron, making that the process is selective. It was observed that the treatment with OU of 60 minutes during the lixiviation of the pulp of mineral lateritic (Serpentine of Nicaro) it was enough. The reported maximum recovery of Neither and Co was: 69% neither and 33% Co. The acid consumption (which represents 70% of the costs of industrial process) was between 11 to 20 t of acid per ton of nickel leached, being lower than the average reported consumption (26 ton acid / ton nickel) in the industrial plant acid pressure leaching in Moa. (Author)

Medical geology of endemic goiter in Kalutara, Sri Lanka; distribution and possible causes.

Science.gov (United States)

Fernando, G W A R; Liyanage, P L C L; Rajapaksha, Anushka Upamali; Vithanage, Meththika

2017-12-01

This study assesses the distribution of goiter in the Kalutara District, Sri Lanka in order to find causative factors for the occurrence of goiter even after the salt iodization. A questionnaire survey was conducted at the household level and at the same time iodine and selenium levels of the water sources were analyzed. Questionnaire survey results indicated the highest numbers of goiter patients in the northern part where the lowest were found in the southern sector which may be due to the presence of acid sulfate soils. Females were more susceptible and it even showed a transmittance between generations. Average iodine concentrations in subsurface water of goiter endemic regions are 28.25 ± 15.47 μg/L whereas non-goiter regions show identical values at 24.74 ± 18.29 μg/L. Surface water exhibited relatively high values at 30.87 ± 16.13 μg/L. Endemic goiter was reported in some isolated patches where iodine and selenium concentrations low, latter was <10 μg/L. The formation of acid sulfate soils in the marshy lands in Kalutara district may lead to transformation of biological available iodine oxidation into volatile iodine by humic substances, at the same time organic matter rich peaty soil may have strong held of iodine and selenium which again induced by low pH and high temperature were suggested as the instrumental factors in the endemic goiter in Kalutara district. Hence, geochemical features such as soil pH, organic matter and thick lateritic cap in the Kalutara goiter endemic area play a role in controlling the available selenium and iodine for food chain through plant uptake and in water.

Groundwater vulnerability assessment using hydrogeologic and geoelectric layer susceptibility indexing at Igbara Oke, Southwestern Nigeria

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T.E. Oni

2017-12-01

Full Text Available Groundwater vulnerability assessment was carried out at Igbara Oke Southwestern Nigeria, with a view to classify the area into vulnerability zones, by applying the electrical resistivity method, using Schlumberger electrode arrays with maximum electrode separation (AB/2 of 65 m in (41 different locations for data acquisition. Geoelectric parameters (layer resistivity and thickness were determined from the interpreted data. The study area comprises four geoelectric layers (topsoil, lateritic layer, weathered/fractured layer and fresh basement. The geoelectric parameters of the overlying layers across the area were used to assess the vulnerability of the underlying aquifers to near-surface contaminants with the aid of vulnerability maps generated. Three models were compared by maps using geo-electrically derived models; longitudinal conductance, GOD (groundwater occurrence, overlying lithology and depth to the aquifer and GLSI (geoelectric layer susceptibility indexing. The total longitudinal conductance map shows the north central part of the study area as a weakly protected (0.1–0.19 area, while the northern and southern parts have poor protective capacity (<0.1; this is in agreement with the GOD method which shows the northern part of the study area as less vulnerable (0–0.1 while the southern part has low/moderate (0.1–0.3 vulnerability to contamination. The longitudinal conductance exaggerates the degree of susceptibility to contamination than the GOD and GLSI models. From the models, vulnerability to contamination can be considered higher at the southern part than the northern part and therefore, sources of contamination like septic tank, refuse dump should be cited far from groundwater development area. Keywords: Aquifer vulnerability, Longitudinal conductance, GOD and GLSI

Oxidative release of chromium from Archean ultramafic rocks, its transport and environmental impact – A Cr isotope perspective on the Sukinda valley ore district (Orissa, India)

International Nuclear Information System (INIS)

Paulukat, Cora; Døssing, Lasse N.; Mondal, Sisir K.; Voegelin, Andrea R.; Frei, Robert

2015-01-01

Highlights: • Cr in lateritic soil profiles in Sukinda valley are partly highly negatively fractionated. • Oxidative weathering and mining operations affect the Cr isotope composition of the local surface water. • Isotopically heavy Cr from land is probably preserved during its transport to the sea. • The environmental impact of toxic Cr(VI) can potentially be diminished by microbial mats. - Abstract: This study investigates Cr isotope fractionation during soil formation from Archean (3.1–3.3 Ga) ultramafic rocks in a chromite mining area in the southern Singhbhum Craton (Orissa, India). The Cr-isotope signatures of two studied weathering profiles, range from non-fractionated mantle values to negatively fractionated values as low as δ 53 Cr = −1.29 ± 0.04‰. Local surface waters are isotopically heavy relative to the soils. This supports the hypothesis that during oxidative weathering isotopically heavy Cr(VI) is leached from the soils to runoff. The impact of mining pollution is observed downstream from the mine where surface water Cr concentrations are significantly increased, accompanied by a shift to less positive δ 53 Cr values relative to upstream unpolluted surface water. A microbial mat sample indicates that microbes have the potential to reduce and immobilize Cr(VI), which could be a factor in controlling the hazardous impact of Cr(VI) on health and environment. The positive Cr isotope signatures of the Brahmani estuary and coastal seawater collected from the Bay of Bengal further indicate that the positively fractionated Cr isotope signal from the catchment area is preserved during its transport to the sea. Isotopically lighter Cr(VI) downstream from the mine is probably back-reduced to Cr(III) during riverine transport leading to similar Cr-isotope values in the estuary as observed upstream from the mine

Assessment of radiological hazards of naturally occurring radioactive materials in cement industry

International Nuclear Information System (INIS)

Aslam, M.; Gul, R.; Ara, T.; Hussain, M.

2012-01-01

A study on the radiological hazard in Portland cement due to the presence of naturally occurring radioactive materials is being carried out. The Portland cement manufactured in the Islamabad/Rawalpindi region of Pakistan, intermediate products (clinker) and the various raw materials which compose the product have been analysed for 226 Ra, 232 Th and 40 K using a gamma spectrometry system with a N-type high-purity germanium detector of 80 % relative efficiency. From the measured gamma ray spectra, specific activities were determined. The mean values of the total specific activity of 226 Ra, 232 Th and 40 K are 34.2±11.9, 29.1±3.6 and 295.1±66.9 Bq kg -1 , respectively in Portland cement, 28.4±8.7, 11.3±1.7 and 63.1±17.3 Bq kg -1 , respectively in lime stone, 8.2±1.9, 16.2±3.9 and 187.7±53.2 Bq kg -1 , respectively in gypsum, 34.7±13.1, 41.2±6.7 and 187.6±17.2 Bq kg -1 , respectively in clay, 41.1±11.8, 39.3±6.9 and 195.1±29.2 Bq kg -1 , respectively in laterite and 51.1±18.2, 23.2±1.2 and 258.4±15.3 Bq kg -1 , respectively in clinker. The radium equivalent activities (Ra eq ), external hazard index (H ex ), internal hazard index (H in ), absorbed dose rate in air (D) and annual effective dose rate (E eff ) were also determined. The measured activity concentrations for these radio nuclides and radiological indices were compared with the reported national and international data. All these measured values are comparable with the worldwide data reported in UNSCEAR publications. (authors)

Impact of coal and rice husk ash on the quality and chemistry of cement clinker

International Nuclear Information System (INIS)

Nawaz, S.; Kanwal, S.; Rahim, U.; Sheikh, N.; Shahzad, K.

2012-01-01

Utilization of rice husk as an alternative fuel for coal is of interest due to its availability in huge quantities in Pakistan and also because its combustion is environmental pollution friendly as it generates much less SOX due to its much lower sulphur content (0.1-0.3%) compared to sulphur content in coals, particularly indeginous coals ranging from 0.6-14.8%. The purpose of present study was to examine the impact of co-firing of rice husk and coal on the quality of cement clinker so as to substitute expensive imported coal with the abundantly available cheaper rice husk to reduce the cost of production of the cement. For this investigation raw feed mix (mixture of limestone, clay, bauxite and laterite in predetermined proportions) used for cement manufacture was mixed with predetermined varying proportions of coal ash and rice husk ash and placed inside a muffle furnace at 1200 degree C - 1500 degree C i-e the temperatures prevailing in the industrial cement kilns, for various periods of time to obtain cement clinker. The quality and chemistry of cement clinker thus produced in the laboratory was experimentally studied to ensure the quality of cement clinker that would be obtained by co-firing of rice husk and coal in different proportions in industrial cement kilns as the coal ash and rice husk ash produced during combustion will get mixed with cement clinker in industrial kilns. The results indicated that there was decrease in the Lime Saturation Factor, Free Lime and Tricalcium Silicate (C3S) content and increase in the Dicalcium Silicate (C2S) content by increasing the rice husk ash and decreasing the coal ash proportion in the clinker. (author)

Risk assessment of drought disaster in southern China

Science.gov (United States)

Wang, Y.

2015-12-01

Abstract: Drought has become an increasing concern in southern China, but the drought risk has not been adequately studied. This study presents a method for the spatial assessment of drought risk in southern China using a conceptual framework that emphasizes the combined role of hazard, vulnerability, and exposure.A drought hazard map was retrieved with a compound index of meteorological drought method in a GIS environment. Normally, a large variation in the disaster-inducing factor implies a high probability of economic/social losses caused by a drought disaster. The map indicated that areas with a higher risk of drought hazard were mainly distributed in mid-east Yunnan and the basins in eastern Sichuan.The vulnerability indices were based on climate factors as well as land use, geomorphological types, soil properties, and drainage density. The water preserving capability of purple calcareous soil in the basins in Sichuan and mid-east Yunnan, and the lateritic red soil in northeastern Guangdong is relatively weak. The main geomorphological features in Guangxi and Guangdong are hills, which leads to a serious expectation of soil and water losses. Thus, the main areas with a high risk of drought vulnerability are mid-east Yunnan and the basins in eastern Sichuan.The exposure indices were based on population density and agricultural production because population and agriculture experience the main impacts of a drought disaster. Higher exposure indices mean higher economic/social losses due to drought disasters. Areas with high exposure indices were mainly distributed in Guangdong and southern Guangxi.The overall risk was then calculated as the product of the hazard, vulnerability, and exposure. The results indicated a higher risk of drought disaster in the basins in eastern Sichuan,, northeastern Yunnan, and northeastern Guangdong. The main factor influencing the risk of a drought disaster was the hazard, but the vulnerability and exposure also played important roles.

The pH-dependent leaching behavior of slags from various stages of a copper smelting process: Environmental implications.

Science.gov (United States)

Jarošíková, Alice; Ettler, Vojtěch; Mihaljevič, Martin; Kříbek, Bohdan; Mapani, Ben

2017-02-01

The leaching behaviors of primary copper (Cu) slags originating from Ausmelt, reverbatory, and converter furnaces operating under a single technological process were compared to a residual slag tailing obtained by slag re-processing via flotation and metal recovery. The EN 12457-2 leaching test, used for assessment of the hazardous properties, was followed by the CEN/TS 14997 pH-static leaching test (pH range 3-12). Both leaching experiments were coupled with a mineralogical investigation of the primary and secondary phases as well as geochemical modeling. Metals (Cd, Cu, Pb, Zn) exhibit the highest leaching at low pH. Under acidic conditions (pH 3-6), Ausmelt slag and slag tailing exhibited higher metal leaching compared to other slag types. Very low leaching of metals (far below EU limits for non-hazardous waste) was observed at natural pH (7.9-9.0) for all the studied slag samples. In contrast, relatively high leaching of As was observed over the entire pH range, especially for Ausmelt slag (exceeding the EU limit for hazardous waste by 1.7×). However, geochemical modeling and scanning electron microscopy indicated that formation of stable Ca-Cu-Pb arsenates and the binding of As to newly formed Fe (oxyhydr)oxides play an important role in efficient As immobilization at the slag-water interface. In contrast, no controls were predicted for Sb, whose leaching was almost pH-independent. Nevertheless Sb leached concentrations at natural pH were below EU limit for hazardous waste. Re-processing of primary Cu slags for metal recovery, and subsequent co-disposal of the resulting slag tailing with dolomite-rich mine tailing and local laterite is suitable for stabilizing the remaining contaminants (except Sb) and limiting their leaching into the environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Geochemical modelling of water-rock interactions at the Osamu Utsumi mine and Morro do Ferro analogue study sites, Pocos de Caldas, Brazil

International Nuclear Information System (INIS)

Nordstrom, D.K.; Puigdomenech, I.; McNutt, R.H.

1990-01-01

Geochemical processes involving water-rock interactions have been modelled using groundwater composition, mineralogical data, ion plots and computations of speciation, non-thermodynamic mass balance and thermodynamic mass transfer for two natural analogue sites near Pocos de Caldas, Brazil: the Osamu Utsumi mine and Morro do Ferro. The main rock type is an alkaline igneous complex composed of volcanic and sub-volcanic phonolites that have been hydrothermally altered and highly weathered. This altered rock mass grades from a laterite at the surface to a saprolite and finally to unweathered, hydrothermally altered bedrock at depth. The mine site contains high concentrations of uranium and Morro do Ferro contains high concentrations of thorium and rare-earths. The reaction models can reproduce the water chemistry and mineral occurences and they were validated by predicting the masses of minerals precipitated and the pH of the final water. The model computations can also reproduce the pH and iron concentrations of the water samples during CO 2 degassing and iron(II) oxidation from exposure to air. The results from the geochemical reaction models reveal that the dominant processes are production of CO 2 in the soil zone through aerobic decay of organic matter, dissolution of fluorite, calcite, K-feldspar, albite and manganese oxides, oxidation of pyrite and sphalerite and precipitation of ferric oxides, silica and kaolinite. Recharge waters are undersaturated with respect to barite and discharging waters and deeper groundwaters are saturated to supersaturated with respect to barite, demonstrating a strong equilibrium solubility control. Strontium isotope data demonstrate that sources other than calcium-bearing minerals are required to account for the dissolved strontium in the ground. These may include K-feldspar, smectite-chlorite mixed-layer clays and goyazite. (author) 24 figs., 4 tabs., 18 refs

Electrical Resistivity Studies Between Subarnarekha And Kansabati Rivers, Paschim Medinipur (W.B.), India: Implication To Groundwater Problems In The Area.

Science.gov (United States)

Panda, K. P.; Jha, M. K.; Sharma, S. P.

2017-12-01

Various parts of the world face acute shortage of groundwater. To solve groundwater problems various approaches are followed. Interlinking of the river is one of the approaches. The southern part of the West Bengal province of India receives huge amount of rainfall (annual 1200mm). Instead of huge amount of rainfall some parts of the area are problematic for groundwater occurrence. Characterization of aquifer in this area is very important for sustainable development of water supply and artificial recharge schemes. Electrical resistivity survey was performed at regular interval from Kharagpur (north) to Subarnrekha River (south) to map the lithological variations in this area. It covers around 25 kilometers distance from Kharagpur with latitude and longitude (22°19'7.3"N 87°18'40"E) to Subarnrekha River (22°15'49.4" N 87°16'45.1" E). To locating a suitable area for artificial recharge and for the characterization of aquifers vertical electrical sounding is a robust method. Resistivity soundings were carried out with an interval of 2 to 3 kilometers. Subsurface resistivity distribution has been interpreted by using very fast simulated annealing (VFSA) global optimization technique. The study reveals that northern part of the area is problematic and does not have suitable aquifer systems. Resistivity distribution is suitable in the southern part of area and corresponds to clayey sand. Interpreted resistivity in the northern part of the area is relatively high and reveals impervious laterite layer. In southern part of the area resistivity varies between 5-10 Ohm-m at depth below 80 m. Based on the resistivity model different types of geologic units are classified and the zone of interests for aquifer has been demarcated.

Misturas de um solo laterítico com cimento e bentonita para uso em cortinas verticais Mixtures of a lateritic soil with cement and bentonite for slurry wall purposes

OpenAIRE

Priscila Batista; Adilson do Lago Leite

2010-01-01

É crescente mundo afora o uso de cortinas verticais para contenção da contaminação em água subterrânea. Os solos lateríticos, pela sua ampla distribuição no Brasil, possuem grande potencial de aplicação nessas obras. Entretanto algumas questões ainda carecem de maior investigação, como a interação e compatibilidade desses solos com a bentonita e o cimento, principais aditivos usados para melhorar as propriedades das cortinas. O presente artigo avalia propriedades de um solo laterítico e suas ...

Grow your own REE deposits: Novel observations from the soils of Southern Portugal

Science.gov (United States)

Hardy, Liam; Smith, Martin; Boyce, Adrian; McDonald, Alison; Heller, Shaun; Bamberger, Axel; Blum, Astrid; Hood, Leo

2017-04-01

questions. Retrieved from European Parliamentary Records Nash, D., & Mclaren, S. (2007). Geochemical Sediments and Landscapes. London: Wiley-Blackwell. Tardy, Y. (1997). Petrology of Laterites & Tropical Soils. Rotterdam: A. A. Balkema.

Properties and application of magnetite-bearing leaching residuum in metals ions removal process

International Nuclear Information System (INIS)

Hredzak, S.; Vaclavikova, M.; Jakabsky, S.; Lovas, M.; Macasek, F.; Kufcakova, J.; Rajec, P.; Kopunec, R.

2003-01-01

The utility of magnetic sorbents is their potential application in heterogeneous systems like suspensions and body liquids, where they can be specifically removed in a magnetic field. Last not least, also the residues of leached iron-nickel laterite ores at the former Sered (Slovakia) hydrometallurgical plant were found to be a suitable magnetic sorbent for the removal of radionuclides and toxic elements from suspensions. Thus, the promising field of utilising of a stock of six million tons, which represents a local environmental problem because of the resulting spread of the so called black dusts, and the chromium contamination of underground waters, is the application in the decontamination of soils. The properties of the Sered residuum (further: SOR) are introduced. SOR, the raw and mechano-chemically activated by the grinding in potassium ferrocyanide solution in vibrating, ball or attrition mills, were used as a semi-natural magnetic sorbent. The parameters of raw and activated SOR are presented. The vibrating mill activation appears as the most efficient in respect of its activation, though the biggest increase of specific surface was achieved by attrition grinding. The soil in vicinity of nuclear facilities is generally contaminated by caesium-137, cobalt-60 and strontium-90 and should be decontaminated down the level of radiocaesium of about 1 kBq/kg. For this reason the sorption properties for Cs + , Sr 2+ , Pb 2+ and Eu 3+ ions were evaluated. The Toth sorption isotherm was used. Speciation by the Tessier and BCR standard leaching procedures indicates differences between the ions. Raw and activated SOR have convenient sorption properties for caesium, strontium, lead and partially also for trivalent lanthanides. That, together with SOR magnetic properties makes them promising for treatment of radioactive contaminated soils and sediments. Sorption of anions was demonstrated by TcO 4- sorption as a result of secondary ion-exchange mechanism. The results of

Geochemistry of organic-rich river waters in Amazonia: Insights on weathering processes of intertropical cratonic terrain

International Nuclear Information System (INIS)

Horbe, Adriana Maria Coimbra; Lages, Anderson da Silva; Moquet, Jean-Sébastien; Santos, Roberto Ventura; Seyler, Patrick

2016-01-01

In this study, eight organic-rich rivers that flow through the Brazilian craton in the southwestern Amazon rainforest are investigated. This investigation is the first of its type in this area and focuses on the effects of lithology, long-term weathering, thick soils, forest cover and hydrological period on the dissolved load compositions in rivers draining cratonic terrain. The major dissolved ion concentrations, alkalinity (TAlk), SiO 2 , trace element concentrations, and Sr isotope contents in the water were determined between April 2009 and January 2010. In addition, the isotopic values of oxygen and hydrogen were determined between 2011 and 2013. Overall, the river water is highly dilute and dominated by the major dissolved elements TAlk, SiO 2 and K + and the major dissolved trace elements Al, Fe, Ba, Mn, P, Zn and Sr, which exhibit large temporal and spatial variability and are closely correlated with the silicatic bedrock and hydrology. Additionally, rainwater and recycled water vapor and the size of the basin contribute to the geochemistry of the waters. The total weathering flux estimated from our results is 2–4 t km −2 .yr −1 , which is one of the lowest fluxes in the world. The CO 2 consumption rate is approximately 21–61 10 3  mol km −2  yr −1 , which is higher than expected given the stability of the felsic to basic igneous and metamorphic to siliciclastic basement rocks and the thick tropical soil cover. Thus, weathering of the cratonic terrain under intertropical humid conditions is still an important consumer of CO 2 . - Highlights: • Were studied rivers flowing the Brazilian craton covered by lateritic soils. • The river waters are highly diluted and dominated by TAlk, SiO 2 and K + . • There is spatial and temporal variability in the chemical composition. • The rain amount and recycled water vapor affect the O and D isotopes. • Geology, weathering, discharge and seasonality highlight a singular composition.

ENVIRONMENTAL IMPACT OF URBANIZATION ON SANTA EULÁLIA SMALL FARM, SÃO LUÍS-MA, BRAZIL

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Marina de Alcântara Rufino

2005-05-01

Full Text Available The small farm Santa Eulália occupies a privileged area in the landscape compositionof the city of São Luis, being situated in one of the vectors of urban expansion, the edges ofthe avenue Euclides Figueiredo, on the northwest of the island of Maranhão, next to thecenter. In the decade of 1980, the small farm was inserted in area of permanent environmentprotection and in the beginning of the decade of 1990, Santa Eulália received great landscapealteration for interest in creating the housing development Santa Eulália for an estimatedpopulation of 35 thousand inhabitants. The intervention was made aiming to organize thegrowth of the city, however the execution of the work generated a great controversy, as muchpolitical as environmental, but also social, with the argument that the area destined to theimplantation of the housing development would be of permanent preservation and placed onthe side of a garbage deposit that served as a deposit of solid residues for all the cities of theisland. After the deforestation of 107.32 hectares and the implantation of the primaryinfrastructure in the place that involved services of embankment, drainage and pavement, thework was seized by the Brazilian Institute of the Environment and Renewable NaturalResources (IBAMA, but the main environmental impacts had already occurred or wasoccurring. Due to the land filling, embankment, previous cut of palm trees and mangrove,some foci of erosion with the creation of several gullies had originated and had a consequentsanding of creeks due to the material carried by the rain, besides that, the exposed soil is poorand with lateritic concretions . These factors made it difficult to attempt the forest resetting ofthe area in study. Therefore, the recovery of all the area becomes necessary in order to leaveit with a profile similar to the original, mainly in the areas considered untouchable for theBrazilian environmental legislation.

Large Igneous Provinces, Their Giant Mafic Dyke Swarms, and Links to Metallogeny

Science.gov (United States)

Jowitt, S.; Ernst, R. E.

2017-12-01

The relationships between large igneous provinces (LIPs), their giant dyke swarms and differing metallogenic systems can be condensed into five distinct although partially overlapping classifications: (1) LIP magmas that directly generate mineral deposits such as orthomagmatic Ni-Cu-PGE sulfides. Many carbonatites (Nb, Ta REE deposits) and kimberlites (diamonds) are also often LIP related. On the other hand, LIP-related thermal pulses (from a mantle plume) can sometimes destroy diamond potential in the overlying lithosphere. A key locus for Ni-Cu-PGE mineralization is within a few hundred km of the plume center region and plume centers are best located using giant radiating dyke swarms. Dyke subswarms with chalcophile element depletions can also be tracked "upstream" toward the plume center to identify exploration targets. (2) LIP magmas that provide energy, fluids, and/or metals for ore types such as hydrothermal volcanogenic massive sulfide (VMS) and iron oxide-copper-gold (IOCG) deposits. Heat loss from the margins of dykes and sills can also generate local enrichments in key metals (e.g. Co) within the surrounding sedimentary rocks. (3) LIP rocks (particularly sills and dykes) can act barriers to fluid flow and/or as reaction zones that control mineralizing events, act as structural traps within hydrocarbon systems, and form impermeable barriers that control water flow and hence aquifer formation (4) surficial effects, such as the formation of Ni-Co laterites and Al bauxites from tropical weathering of LIP mafic-ultramafic rocks (including volcanics fed by radiating dykes as well as the dykes themselves). This category also includes LIP-related anoxia events that generate hydrocarbon source rocks; and (5) indirect links between LIPs and ore deposits, where continental breakup-related LIP events define a `barcode' record (usually dominated by dyke swarms) that can be used to correlate and reconstruct Precambrian supercontinents. This fifth classification type

Heat-flow and subsurface temperature history at the site of Saraya (eastern Senegal)

Science.gov (United States)

Lucazeau, F.; Rolandone, F.

2012-08-01

New temperature measurements from eight boreholes in the West African Craton (WAC) reveal superficial perturbations down to 100 m below the alteration zone. These perturbations are both related to a recent increase in the surface air temperature (SAT) and to the site effects caused by fluid circulations and/or the lower conduction in the alterites. The ground surface temperature (GST), inverted from the boreholes temperatures, increased slowly in the past (~0.4 °C from 1700 to 1940) and then, more importantly, in recent years (~1.5 °C from 1940 to 2010). This recent trend is consistent with the increase of the SAT recorded at two nearby meteorological stations (Tambacounda and Kedougou), and more generally in the Sahel with a coeval rainfall decrease. Site effects are superimposed to the climatic effect and interpreted by advective (circulation of fluids) or conductive (lower conductivity of laterite and of high-porosity sand) perturbations. We used a 1-D finite differences thermal model and a Monte-Carlo procedure to find the best estimates of these site perturbations: all the eight borehole temperature logs can be interpreted with the same basal heat-flow and the same surface temperature history, but with some realistic changes of thermal conductivity and/or fluid velocity. The GST trend observed in Senegal can be confirmed by two previous borehole measurements made in 1983 in other locations of West Africa, the first one in an arid zone of northern Mali and the second one in a sub-humid zone in southern Mali. Finally, the background heat-flow is low (31±2 mW m-2), which makes this part of the WAC more similar with the observations in the southern part (33±8 mW m-2) rather than with those in the northern part and in the Pan-African domains where the surface heat-flow is 15-20 mW m-2 higher.

Cobalt—Styles of deposits and the search for primary deposits

Science.gov (United States)

Hitzman, Murray W.; Bookstrom, Arthur A.; Slack, John F.; Zientek, Michael L.

2017-11-30

Cobalt (Co) is a potentially critical mineral. The vast majority of cobalt is a byproduct of copper and (or) nickel production. Cobalt is increasingly used in magnets and rechargeable batteries. More than 50 percent of primary cobalt production is from the Central African Copperbelt. The Central African Copperbelt is the only sedimentary rock-hosted stratiform copper district that contains significant cobalt. Its presence may indicate significant mafic-ultramafic rocks in the local basement. The balance of primary cobalt production is from magmatic nickel-copper and nickel laterite deposits. Cobalt is present in several carbonate-hosted lead-zinc and copper districts. It is also variably present in Besshi-type volcanogenic massive sulfide and siliciclastic sedimentary rock-hosted deposits in back arc and rift environments associated with mafic-ultramafic rocks. Metasedimentary cobalt-copper-gold deposits (such as Blackbird, Idaho), iron oxide-copper-gold deposits, and the five-element vein deposits (such as Cobalt, Ontario) contain different amounts of cobalt. None of these deposit types show direct links to mafic-ultramafic rocks; the deposits may result from crustal-scale hydrothermal systems capable of leaching and transporting cobalt from great depths. Hydrothermal deposits associated with ultramafic rocks, typified by the Bou Azzer district of Morocco, represent another type of primary cobalt deposit.In the United States, exploration for cobalt deposits may focus on magmatic nickel-copper deposits in the Archean and Proterozoic rocks of the Midwest and the east coast (Pennsylvania) and younger mafic rocks in southeastern and southern Alaska; also, possibly basement rocks in southeastern Missouri. Other potential exploration targets include—The Belt-Purcell basin of British Columbia (Canada), Idaho, Montana, and Washington for different styles of sedimentary rock-hosted cobalt deposits;Besshi-type VMS deposits, such as the Greens Creek (Alaska) deposit and

Persistence of Pathogenic and Non-Pathogenic Escherichia coli Strains in Various Tropical Agricultural Soils of India.

Directory of Open Access Journals (Sweden)

S Naganandhini

Full Text Available The persistence of Shiga-like toxin producing E. coli (STEC strains in the agricultural soil creates serious threat to human health through fresh vegetables growing on them. However, the survival of STEC strains in Indian tropical soils is not yet understood thoroughly. Additionally how the survival of STEC strain in soil diverges with non-pathogenic and genetically modified E. coli strains is also not yet assessed. Hence in the present study, the survival pattern of STEC strain (O157-TNAU was compared with non-pathogenic (MTCC433 and genetically modified (DH5α strains on different tropical agricultural soils and on a vegetable growing medium, cocopeat under controlled condition. The survival pattern clearly discriminated DH5α from MTCC433 and O157-TNAU, which had shorter life (40 days than those compared (60 days. Similarly, among the soils assessed, the red laterite and tropical latosol supported longer survival of O157-TNAU and MTCC433 as compared to wetland and black cotton soils. In cocopeat, O157 recorded significantly longer survival than other two strains. The survival data were successfully analyzed using Double-Weibull model and the modeling parameters were correlated with soil physico-chemical and biological properties using principal component analysis (PCA. The PCA of all the three strains revealed that pH, microbial biomass carbon, dehydrogenase activity and available N and P contents of the soil decided the survival of E. coli strains in those soils and cocopeat. The present research work suggests that the survival of O157 differs in tropical Indian soils due to varied physico-chemical and biological properties and the survival is much shorter than those reported in temperate soils. As the survival pattern of non-pathogenic strain, MTCC433 is similar to O157-TNAU in tropical soils, the former can be used as safe model organism for open field studies.

Geomorphological and hydrogeological features of the Pocos de Caldas caldera and the Osamu Utsumi mine and Morro do Ferro analogue study sites, Brazil

International Nuclear Information System (INIS)

Holmes, D.C.; Pitty, A.E.; Noy, D.J.

1990-01-01

The Osamu Utsumi mine and Morro do Ferro study sites lie within the Pocos de Caldas plateau which is roughly circular in outline with a diameter of 35 km and an area of approximately 800 km 2 . Its general altitude lies between 1300 and 1600 m. The plateau is the eroded form of a caldera which was initially intruded some 80 million years ago. Geomorphologically, both sites occupy watershed areas adjacent to small streams in the centre of the plateau. The climate of the area has a market wet season from November to April and is dry the rest of the year. The streams are ephemeral in their upper reaches, tending to dry up in the dry season as they are fed by a declining base flow. In the wet season they exhibit flash flood fed by high-intensity rainfall causing overland flow. The wet season also provides recharge to the groundwater. Natural slopes are steep and the original vegetation was thin forest cover which is now restricted to the valley bottoms; usable slopes have poor quality grass cover used for cattle grazing. The plateau is a stable feature and its surface has been eroding at an average rate of 12 m per million years over a period of 50 million years. The mine geology is dominantly volcanic to subvolcanic phonolites that have been hydrothermally altered. Fracturing of the rock is extensive. Downward diffusion of oxygen in groundwaters during deep weathering has produced a distinct redox zone seen as a colour change from green/grey to brown/yellow. Morro do Ferro has a more weathered version (laterite/clay) of the same geology penetrated by magnetite breccia dykes. Whilst the area surrounding Morro do Ferro remains untouched, that around the mine has been seriously disturbed by mining activity which has penetrated the water-table. The existing mine has modified groundwater flow patterns and disturbed the movement of oxidising and reducing waters. (au) (47 refs.)

Physical and Mechanical Properties of Compressed Earth Brick (CEB Containing Sugarcane Bagasse Ash

Directory of Open Access Journals (Sweden)

Ali Noorwirdawati

2016-01-01

Full Text Available The use of brick in construction is commonly used, especially in the construction of buildings and infrastructure. Various studies have been conducted to produce methods that can increase the strength of brick at the same time can reduce the cost of manufacturing bricks. In order to reduce cost of manufacturing, one of the solution applied was by using waste as part of bricks production materials. In this study, sugarcane bagasse (SuCaB ash was used as a part of compressed earth brick (CEB by replacing the quantity of cement for SuCaB ash. The study focused on the physical and mechanical properties of CEB containing SuCaB and the optimum percentage of SuCaB ash as partial cement replacement in CEB. There are 4 types of percentages used; 0%, 20%, 25% and 30% from cement content. All mixed use the same water content of 30% of cement content by weight and the ratio for cement: laterite soil used was 1: 6. A total of 72 specimen with size of 100mm × 50mm × 40mm was produced. The test conducted were Initial Rate Absorption Test (IRA, Density Test, Dimensions Test, Compression Test and Water Absorption Test. From the experimental results, the optimum SuCaB ash percentage as cement replacement in CEB was 20%. It recorded the highest compressive strength of 16.23 MPa at 28 days while for the Initial Rate Absorption test, it lies within the range specified. The density of CEB containing 20% of SuCaB shows slightly lower value where it decreased for about 0.4% from the control specimen. From this study, it can be concluded that waste materials such as sugarcane bagasse can be used as part of construction materials. However, further study needs to be conducted such as on the energy consumption, chemical properties and others to enhance the knowledge on this area before it can be applied into the brick production.

Joint application of ground penetrating radar and electrical resistivity measurements for characterization of subsurface stratigraphy in Southwestern Nigeria

International Nuclear Information System (INIS)

Adepelumi, A A; Fayemi, O

2012-01-01

The frequent building collapses in Nigeria have been attributed to a lack of pre-construction investigations, which assist engineers in obtaining in situ geotechnical information. Further, the structural subsurface settings are often ignored or investigation is haphazardly carried out. To address this issue and demonstrate the importance of such a survey, a combination of ground penetrating radar (GPR) and vertical electrical sounding (VES) data were acquired in a part of Southwestern Nigeria. A 200 MHz antenna was used for the data acquisition along four traverses. The data were subjected to standard GPR processing techniques, and attribute analysis such as instantaneous frequency, amplitude and phase. Also, for comparative and engineering characterization purposes, longitudinal conductance and coefficient of anisotropy were computed from the VES results and used for determining the competency of the bedrocks. From the GPR results, it was observed that the mapped subsurface is characterized as erosional truncated at a low angle, which is southerly dipping and includes tangential reflections. Further, stratified rocks dipping at an angle of 32° occur between 1.0 and 4.5 m depth in all of the GPR sections; these strata were truncated by topsoil at shallow depths. Also, some of the sections depict ancient channel structures that have a dimension of 70 m × 40 m. The resistivity data suggest that the study area is characterized by four distinct geoelectric sequences. These comprise topsoil which is composed of clay-like sand to lateritic clay whose thickness ranges between 0.25 and 8.12 m, weathered bedrock with a thickness between 3.84 and 12.61 m, stratified bedrock with a thickness between 0.33 and 7.51 m, and fresh bedrock. These results reveal a complex subsurface geology and this characterizes the study area. The area has low to moderate longitudinal conductance and coefficient of anisotropy values, which suggest that incompetent to semi-competent bedrock

Rare earth minerals and resources in the world

Energy Technology Data Exchange (ETDEWEB)

Kanazawa, Yasuo [Human Resource Department, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba 305-8568 (Japan)]. E-mail: y.kanazawa@aist.go.jp; Kamitani, Masaharu [Institute for Geo-Resources and Environment, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8567 (Japan)

2006-02-09

About 200 rare earth (RE) minerals are distributed in a wide variety of mineral classes, such as halides, carbonates, oxides, phosphates, silicates, etc. Due to the large ionic radii and trivalent oxidation state, RE ions in the minerals have large coordination numbers (c.n.) 6-10 by anions (O, F, OH). Light rare earth elements (LREEs) tend to occupy the larger sites of 8-10 c.n. and concentrate in carbonates and phosphates. On the other hand, heavy rare earth elements (HREEs) and Y occupy 6-8 c.n. sites and are abundant in oxides and a part of phosphates. Only a few mineral species, such as bastnaesite (Ce,La)(CO{sub 3})F, monazite (Ce,La)PO{sub 4}, xenotime YPO{sub 4}, and RE-bearing clay have been recovered for commercial production. Bayan Obo, China is the biggest RE deposit in the world. One of probable hypotheses for ore geneses is that the deposit might be formed by hydrothermal replacement of carbonate rocks of sedimentary origin. The hydrothermal fluid may be derived from an alkaline-carbonatite intrusive series. Following Bayan Obo, more than 550 carbonatite/alkaline complex rocks constitute the majority of the world RE resources. The distribution is restricted to interior and marginal regions of continents, especially Precambrian cratons and shields, or related to large-scale rift structures. Main concentrated areas of the complexes are East African rift zones, northern Scandinavia-Kola peninsula, eastern Canada and southern Brazil. Representative sedimentary deposits of REE are placer- and conglomerate-types. The major potential countries are Australia, India, Brazil, and Malaysia. Weathered residual deposits have been formed under tropical and sub-tropical climates. Bauxite and laterite nickel deposit are the representative. Ion adsorption clay without radioactive elements is known in southern China. Weathering processes concentrate REE in a particular clay mineral-layer in the weathered crusts whose source were originally REE-rich rocks like granite

Rare earth minerals and resources in the world

International Nuclear Information System (INIS)

Kanazawa, Yasuo; Kamitani, Masaharu

2006-01-01

About 200 rare earth (RE) minerals are distributed in a wide variety of mineral classes, such as halides, carbonates, oxides, phosphates, silicates, etc. Due to the large ionic radii and trivalent oxidation state, RE ions in the minerals have large coordination numbers (c.n.) 6-10 by anions (O, F, OH). Light rare earth elements (LREEs) tend to occupy the larger sites of 8-10 c.n. and concentrate in carbonates and phosphates. On the other hand, heavy rare earth elements (HREEs) and Y occupy 6-8 c.n. sites and are abundant in oxides and a part of phosphates. Only a few mineral species, such as bastnaesite (Ce,La)(CO 3 )F, monazite (Ce,La)PO 4 , xenotime YPO 4 , and RE-bearing clay have been recovered for commercial production. Bayan Obo, China is the biggest RE deposit in the world. One of probable hypotheses for ore geneses is that the deposit might be formed by hydrothermal replacement of carbonate rocks of sedimentary origin. The hydrothermal fluid may be derived from an alkaline-carbonatite intrusive series. Following Bayan Obo, more than 550 carbonatite/alkaline complex rocks constitute the majority of the world RE resources. The distribution is restricted to interior and marginal regions of continents, especially Precambrian cratons and shields, or related to large-scale rift structures. Main concentrated areas of the complexes are East African rift zones, northern Scandinavia-Kola peninsula, eastern Canada and southern Brazil. Representative sedimentary deposits of REE are placer- and conglomerate-types. The major potential countries are Australia, India, Brazil, and Malaysia. Weathered residual deposits have been formed under tropical and sub-tropical climates. Bauxite and laterite nickel deposit are the representative. Ion adsorption clay without radioactive elements is known in southern China. Weathering processes concentrate REE in a particular clay mineral-layer in the weathered crusts whose source were originally REE-rich rocks like granite and

The epidemiology of human and animal schistosomiasis in the Senegal River Basin.

Science.gov (United States)

Vercruysse, J; Southgate, V R; Rollinson, D

1985-09-01

The results of four field surveys in Senegal are reported. 1. A snail survey in various parts of the Senegal River Basin, including the Senegal River, temporary rain-fed pools, swamps, irrigation canals and drains, ricefields and Lac de Guier was carried out. Three species of snails were commonly found: Bulinus guernei was the most common, occurring in permanent habitats, Bulinus senegalensis occurring in laterite pools in the eastern part of the Middle Valley, and also in the ricefields of Guédé Chantier and Lampsar; B. forskalii was found in small numbers in Lac de Guier and Richard Toll. Three B. guernei were found to be naturally infected with S. bovis. Neither B. jousseaumei, B. globosus nor B. umbilicatus were found in our surveys. 2. A survey for urinary schistosomiasis was carried out in 100 villages (walo, near the Senegal River) and 11 villages (diéré, away from the river) by delivering questionnaires in schools and by direct examinations of haematuria samples. The prevalence of haematuria varied between 0 and 33%. Generally, walos showed low rates of haematuria with the exception of Lampsar and Guédé Chantier, and diérés showed higher rates of haematuria. 3. Examination of 400 cattle at the abattoir St. Louis, revealed a prevalence of 80% of schistosome infection. Two species were present, S. bovis and less commonly S. curassoni. Sometimes high worm burdens were seen, but lesions appeared to be minimal because of high ratio of male to female worms. 4. Examinations of 5722 sheep and 1752 goats in the abattoir, Dakar revealed an overall prevalence of 2.1%. Of the infected animals, 97.3% were infected with S. curassoni and 2.7% with S. curasonni and S. bovis. Laboratory snail infection experiments showed that S. curassoni is marginally compatible with B. senegalensis, but incompatible with B. guernei.

Emerging mitigation needs and sustainable options for solving the arsenic problems of rural and isolated urban areas in Latin America - a critical analysis.

Science.gov (United States)

Bundschuh, Jochen; Litter, Marta; Ciminelli, Virginia S T; Morgada, María Eugenia; Cornejo, Lorena; Hoyos, Sofia Garrido; Hoinkis, Jan; Alarcón-Herrera, Ma Teresa; Armienta, María Aurora; Bhattacharya, Prosun

2010-11-01

In this work, current information about the contamination of ground- and surface-water resources by arsenic from geogenic sources in Latin America is presented together with possible emerging mitigation solutions. The problem is of the same order of magnitude as other world regions, such as SE Asia, but it is often not described in English. Despite the studies undertaken by numerous local researchers, and the identification of proven treatment methods for the specific water conditions encountered, no technologies have been commercialized due to a current lack of funding and technical assistance. Emerging, low-cost technologies to mitigate the problem of arsenic in drinking water resources that are suitable for rural and urban areas lacking centralized water supplies have been evaluated. The technologies generally use simple and low-cost equipment that can easily be handled and maintained by the local population. Experiences comprise (i) coagulation/filtration with iron and aluminum salts, scaled-down for small community- and household-scale-applications, (ii) adsorption techniques using low-cost arsenic sorbents, such as geological materials (clays, laterites, soils, limestones), natural organic-based sorbents (natural biomass), and synthetic materials. TiO(2)-heterogeneous photocatalysis and zerovalent iron, especially using nanoscale particles, appear to be promising emergent technologies. Another promising innovative method for rural communities is the use of constructed wetlands using native perennial plants for arsenic rhizofiltration. Small-scale simple reverse osmosis equipment (which can be powered by wind or solar energy) that is suitable for small communities can also be utilized. The individual benefits of the different methods have been evaluated in terms of (i) size of the treatment device, (ii) arsenic concentration and distribution of species, chemical composition and grade of mineralization in the raw water, (iii) guidelines for the remaining As

Foundation integrity assessment using integrated geophysical and geotechnical techniques: case study in crystalline basement complex, southwestern Nigeria

Science.gov (United States)

Olayanju, G. M.; Mogaji, K. A.; Lim, H. S.; Ojo, T. S.

2017-06-01

The determination of parameters comprising exact depth to bedrock and its lithological type, lateral changes in lithology, and detection of fractures, cracks, or faults are essential to designing formidable foundations and assessing the integrity of civil engineering structures. In this study, soil and site characterization in a typical hard rock geologic terrain in southwestern Nigeria were carried out employing integrated geophysical and geotechnical techniques to address tragedies in civil engineering infrastructural development. The deployed geophysical measurements involved running both very low frequency electromagnetic (VLF-EM) and electrical resistivity methods (dipole-dipole imaging and vertical electrical sounding (VES) techniques) along the established traverses, while the latter technique entailed conducting geological laboratory sieve analysis and Atterberg limit-index tests upon the collected soil samples in the area. The results of the geophysical measurement, based on the interpreted VLF-EM and dipole-dipole data, revealed conductive zones and linear features interpreted as fractures/faults which endanger the foundations of public infrastructures. The delineation of four distinct geoelectric layers in the area—comprised of topsoil, lateritic/clayey substratum, weathered layer, and bedrock—were based on the VES results. Strong evidence, including high degree of decomposition and fracturing of underlying bedrock revealed by the VES results, confirmed the VLF-EM and dipole-dipole results. Furthermore, values in the range of 74.2%-77.8%, 55%-62.5%, 23.4%-24.5%, 7.7%-8.2%, 19.5%-22.4%, and 31.65%-38.25% were obtained for these geotechnical parameters viz soil percentage passing 0.075 mm sieve size, liquid limit, plasticity index, linear shrinkage, natural moisture content, and plastic limit, respectively, resulting from the geotechnical analysis of the soil samples. The comparatively analyzed geophysical and geotechnical results revealed a high

Trace metal geochemistry in mangrove sediments and their transfer to mangrove plants (New Caledonia)

International Nuclear Information System (INIS)

Marchand, C.; Fernandez, J.-M.; Moreton, B.

2016-01-01

Because of their physico-chemical inherent properties, mangrove sediments may act as a sink for pollutants coming from catchments. The main objective of this study was to assess the distribution of some trace metals in the tissues of various mangrove plants developing downstream highly weathered ferralsols, taking into account metals partitioning in the sediment. In New Caledonia, mangroves act as a buffer between open-cast mines and the world's largest lagoon. As a result of the erosion of lateritic soils, Ni and Fe concentrations in the sediment were substantially higher than the world average. Whatever the mangrove stand and despite low bioaccumulation and translocations factors, Fe and Ni were also the most abundant metals in the different plant tissues. This low bioaccumulation may be explained by: i) the low availability of metals, which were mainly present in the form of oxides or sulfur minerals, and ii) the root systems acting as barriers towards the transfer of metals to the plant. Conversely, Cu and Zn metals had a greater mobility in the plant, and were characterized by high bioconcentration and translocation factors compared to the other metals. Cu and Zn were also more mobile in the sediment as a result of their association with organic matter. Whatever the metal, a strong decrease of trace metal stock was observed from the landside to the seaside of the mangrove, probably as a result of the increased reactivity of the sediment due to OM enrichment. This reactivity lead to higher dissolution of bearing phases, and thus to the export of dissolved trace metals trough the tidal action. Cu and Zn were the less concerned by the phenomenon probably as a result of higher plant uptake and their restitution to the sediment with litter fall in stands where tidal flushing is limited. - Highlights: • Unusual high concentrations of Fe and Ni were measured in mangrove tissues. • Bioconcentration and translocation factors of Fe, Ni, Co and Mn were low. • Low

Trace metal geochemistry in mangrove sediments and their transfer to mangrove plants (New Caledonia)

Energy Technology Data Exchange (ETDEWEB)

Marchand, C., E-mail: cyril.marchand@ird.fr [Institut de Recherche pour le Développement (IRD), UR 206/UMR 7590 IMPMC, 98848 Nouméa, New Caledonia (France); Fernandez, J.-M.; Moreton, B. [AEL/LEA, 7 rue Loriot de Rouvray, 98800 Nouméa, New Caledonia (France)

2016-08-15

Because of their physico-chemical inherent properties, mangrove sediments may act as a sink for pollutants coming from catchments. The main objective of this study was to assess the distribution of some trace metals in the tissues of various mangrove plants developing downstream highly weathered ferralsols, taking into account metals partitioning in the sediment. In New Caledonia, mangroves act as a buffer between open-cast mines and the world's largest lagoon. As a result of the erosion of lateritic soils, Ni and Fe concentrations in the sediment were substantially higher than the world average. Whatever the mangrove stand and despite low bioaccumulation and translocations factors, Fe and Ni were also the most abundant metals in the different plant tissues. This low bioaccumulation may be explained by: i) the low availability of metals, which were mainly present in the form of oxides or sulfur minerals, and ii) the root systems acting as barriers towards the transfer of metals to the plant. Conversely, Cu and Zn metals had a greater mobility in the plant, and were characterized by high bioconcentration and translocation factors compared to the other metals. Cu and Zn were also more mobile in the sediment as a result of their association with organic matter. Whatever the metal, a strong decrease of trace metal stock was observed from the landside to the seaside of the mangrove, probably as a result of the increased reactivity of the sediment due to OM enrichment. This reactivity lead to higher dissolution of bearing phases, and thus to the export of dissolved trace metals trough the tidal action. Cu and Zn were the less concerned by the phenomenon probably as a result of higher plant uptake and their restitution to the sediment with litter fall in stands where tidal flushing is limited. - Highlights: • Unusual high concentrations of Fe and Ni were measured in mangrove tissues. • Bioconcentration and translocation factors of Fe, Ni, Co and Mn were low. �

Mining run-off gets a treatment

International Nuclear Information System (INIS)

Pichon, Max

2013-01-01

Full text: Engineering company GHD has implemented an innovative multi- barrier storm water treatment system for a major milling company at the Port of Townsville. The technology economically filters stormwater and is effective for a broad range of contaminants including oil, grease, soluble nutrients and heavy metals. GHD's industrial water and coal seam gas business development leader, Kostas Athanasiadis, created StormDMT, a configuration of inexpensive filter media in a cartridge that cost-effectively removes heavy metals and other dissolved contaminants. He said there was growing recognition of the need to protect receiving waterways and to address water scarcity through measures such as stormwater harvesting. “However, there are few stormwater treatment technologies currently available to effectively and economically remove these contaminants both in particulate and soluble forms, to desirable levels,” he said. GHD carried out a trial at the site in collaboration with the client's engineering, environmental and operational teams. The filter exceeded anticipated performance and the client has adopted a site-wide solution based on the technology. The StormDMT stormwater filter system design incorporates a filtering system (cartridge or other types of filtering configurations) that contains a combination of filter media, including polypropylene flakes to remove oil and grease and particulate-bound contaminants. It also features a zeolite named clinoptilolite to remove positive charged dissolved contaminants such as heavy metals and ammonium nitrogen. Clinoptilolite has been chemically conditioned to maximise its operational ion exchange capacity. Finally, laterite removes negative charged contaminants such as phosphate, nitrate and arsenic as well as heavy metals that have broken through the clinotpilolite layer. One of the key advantages of the StormDMT technology is the low discharge levels it is capable of achieving or dissolved nutrients and

Reevaluation of 1935 M 7.0 earthquake fault, Miaoli-Taichung Area, western Taiwan: a DEM and field study

Science.gov (United States)

Lin, Y. N.; Chen, Y.; Ota, Y.

2003-12-01

A large earthquake (M 7.0) took place in Miaoli area, western Taiwan on April 21st, 1935. Right to its south is the 1999 Chi-Chi earthquake fault, indicating it is not only tectonically but seismically active. As the previous study, the study area is located in the mature zone of a tectonic collision that occurred between Philippine sea Plate and Eurasia continental Plate. The associated surface ruptures of 1935 earthquake daylighted Tungtsichiao Fault, a tear fault trending NE in the south and Chihhu Fault, a back thrust trending N-S in the north, but no ruptures occurred in between. Strike-slip component was identified by the horizontal offset observed along Tungtsichiao Fault; however, there are still disputes on the reported field evidence. Our purposes are (1) to identify the structural behaviors of these two faults, (2) to find out what the seismogenic structure is, and (3) to reconstruct the regional geology by information given by this earthquake. By DEM interpretation and field survey, we can clearly recognize a lot of the 1935 associated features. In the west of Chihhu Fault, a series of N-S higher terraces can be identified with eastward tilted surfaces and nearly 200 m relative height. Another lower terrace is also believed being created during the 1935 earthquake, showing an east-facing scarp with a height of ca. 1.5~2 m. Outcrop investigation reveals that the late-Miocene bedrock has been easterly thrusted over the Holocene conglomerates, indicating a west-dipping fault plane. The Tungtsichiao Fault cuts through a lateritic terrace at Holi, which is supposed developed in Pleistocene. The fault scarp is only discernible in the northeastern ending. Other noticeable features are the fault related antiforms that line up along the surface rupture. There is no outcrop to show the fault geometry among bedrocks. We re-interpret the northern Chihhu Fault as the back thrust generated from a main subsurface detachment, which may be the actual seismogenic fault

Geomorphological and Geoelectric Techniques for Kwoi's Multiple Tremor Assessment

Science.gov (United States)

Dikedi, P. N.

2017-12-01

This work epicentres on geomorphological and geoelectric techniques for multiple tremor assessment in Kwoi, Nigeria. Earth tremor occurrences have been noted by Akpan and Yakubu (2010) within the last 70 years, in nine regions in Nigeria; on September 11,12,20,22, 23 and 24, 2016, additional earth tremors rocked the village of Kwoi eleven times. Houses cracked and collapsed, a rock split and slid and smoke evolved at N9027''5.909''', E800'44.951'', from an altitude of 798m. By employing the Ohmega Meter and Schlumberger configuration, four VES points are sounded for subsurface structure characterisation. Thereafter, a cylindrical steel ring is hammered into the ground at the first point (VES 1) and earth samples are scooped from this location; this procedure is repeated for other points (VES 2, 3 and 4). Winresist, Geo-earth, and Surfer version 12.0.626 software are employed to generate geo-sections, lithology, resistivity profile, Iso resistivity and Isopach maps, of the region. Outcome of results reveal some lithological formations of lateritic topsoil, fractured basement and fresh basement; additionally, results reveal 206.6m, 90.7m, 73.2m and 99.4m fractured basement thicknesses for four points. Scooped samples are transferred to the specimen stage of a Scanning Electron Microscope (SEM). SEM images show rounded inter-granular boundaries—the granular structures act like micro-wheels making the upper crustal mass susceptible to movement at the slightest vibration. Collapsed buildings are sited around VES1 location; samples from VES 1 are the most well fragmented sample owing to multiple microfractures—this result explains why VES 1 has the thickest fractured basement. Abrupt frictional sliding occurs between networks of fault lines; there is a likelihood that friction is most intense at the rock slide site on N9027'21.516'' and E800'44.9993'', VES 1 at N9027'5.819'' and E8005'3.1120'' and smoke sites—holo-centres are suspected below these locations. The

GPR para a verificação do nível d'água subterrânea em transição floresta amazônica e cerrado Ground Penetratin Radar (GPR water level monitoring study of a mature transitional tropical forest

Directory of Open Access Journals (Sweden)

Tânia Helena Marcelino

2005-09-01

Full Text Available Um estudo do monitoramento do nível de água foi realizado com medidas diretas e com Radar de Penetração no Solo (GPR em uma floresta tropical de transição para o cerrado. Três poços de monitoramento do nível de água foram instalados durante 2001/2002 em três locais diferentes: o primeiro em uma área de floresta permanente, outro em área de floresta manejada e outra em uma área de pasto. Os perfis de GPR mostram que o nível do topo do lençol freático aparece como um refletor horizontal forte em março e em agosto de 2002, e como um refletor fraco durante medidas em maio e outubro de 2001 com descontinuidades devido a diversas lentes de solo laterítico no solo. O topo do lençol de água é facilmente confundido com a presença de tais lentes. A umidade do solo teve uma influência nestes sinais da reflexão, mudando a constante dielétrica do solo. A profundidade do topo do lençol da água variou 1,8 m sob a floresta permanente, 0,9 m sob a floresta manejada e 3,7 m sob o pasto.A Ground Penetratin Radar (GPR water level monitoring study of a mature transitional tropical forest is presented. Three water tables monitoring wells were installed during 2001/2002 at three different sites: under permanent forest, under managed forest and pasture. The GPR profiles show that the water table appears as a strong horizontal reflector in March and August, 2002,and as a weak, discontinuous reflector during measurements in May and October 2001. Due to several laterite lenses in the soil, the water table can easily be mistaken in place of such lenses. Soil moisture had an influence on these reflection signals, changing the dielectric constant of soil. The depth of the water table varied 1.8 m under permanent forest, 0.9 m under management forest and 3.7 m under pasture.

Colours Convey Lanna Identity in Lamphun and Chiang Mai Area

Science.gov (United States)

Raksawin, Karuna; Wonglaksanapan, Arphaphon; Suthasupa, Supagtra

2017-10-01

Colour control is a specific tool to identify local environment. Especially in the historic area or conservation area, to promote colour control is very necessary. Therefore, there are many standards of colour to control such as Munsell, colour name, and L*a*b*. This research is aimed to analyze the appropriate colour control by using a Munsell standard colour which is suitable to visual perception. The study area is scoped in northern region of Lanna culture in Thailand which nowadays used names of colours to control. Chiang Mai and Lamphun are selected to be case study because they are in a center of Lanna Empire of Thailand and have many historic significant things such as city wall, temple, monastery, palace, and city moat. The mainly procedure conducts in this article is based on the analysis of material colour. The study chose local natural materials which are used in the historic significant things. Earthen clay tile, wooden roof tile, burnt clay brick, laterites, hard wood, bamboo, silver, and gold are evaluated. The procedure used the DIC application of android processor on smart phone. This application has a conversion data to switch a colour value from pick-up point in photo to many colour values such as RGB, CMYK which Munsell value is included. The photos were taken within the historic area of Chiang Mai and Lamphun by random. The result can scope a range of colours of Munsell standard of natural colour (N), red (R), yellow (Y), and yellow-red (YR). A natural colour (N) can be suggested a range 1.0-9.0 (N 1.0-9.0). Red can be ranged the value between 3.0-7.0 and chroma between 3.0-9.0 (R 3.0-7.0/3.0-9.0). Yellow can be ranged the value between 6.0-9.0 and chroma between 4.0-12.0 (Y 6.0-9.0/4.0-12.0). Yellow-red can be ranged the value between 2.0-8.0 and chroma between 2.0-11.0 (YR 2.0-8.0/2.0-11.0). The results can be revealed a process of colour analysis of historic colour control and may offer to be an ordinance in further.

Review of cenozoic ooidal ironstones

Science.gov (United States)

van Houten, Franklyn B.

1992-06-01

Cenozoic (Tertiary) ooidal ironstones (COI) in 20 districts (39 deposits) developed between the equatorial zone and 60° N, except for one Eocene district in mid-southern latitude. Stratigraphic distribution. Paleocene OI occur in northern Pakistan, western Siberia, southern Germany, northwestern Venezuela, and northeastern Colombia: Eocene OI in western Siberia, southern Germany, northwestern Romania, central North Africa, central-west Saudi Arabia, southwestern Central Africa, northwestern Venezuela, northeastern Colombia, south-central USA, and northwestern Australia; Oligocene OI in northwest and west-central Kazakhstan, central Denmark, and north-central Iran?; Miocene OI in northwestern Venezuela, northeastern Colombia, and southeastern Malaysia; Pliocene OI in southeastern Ukraine. Geotectonic framework. Ten districts developed in an interior or fractured craton: five along the south-trending Uralian Seaway, and one along the east-trending Northern European Seaway, the south-trending Trans-Saharan Seaway, in or near an early Red Sea embayment, in southeastern Malaysia, and in northwestern Australia. Ten districts lay near a eratonic margin: one along divergent margin and nine along the broad east-trending Caribbean and Tethyan seaways. Almost all COI accumulated during the Paleogene relatively high stand of sea level, especially in Early and Middle Eocene time. As sea level fell gradually in Neogene time COI developed in only three marginal districts (including the giant Pliocene Kerch-Taman deposit in southeastern Ukraine). Sedimentary environment. Almost all of the COI developed in deltaic to shallow marine facies. These are commonly associated with shoaling-upward siliciclastic sequences; a few are in mixed siliciclastic-carbonate sequences. A few COI apparently occurred in fluvial and lacustrine facies; some of these may have been reworked from laterite or from marine ironstones. Sedimentary petrology. Many COI are less than a few tens of centimeters

When did a Mediterranean-type climate originate in southwestern Australia?

Science.gov (United States)

Lamont, Byron B.; He, Tianhua

2017-09-01

Knowing the environments under which biota have evolved is essential for understanding the functional traits that they possess. Here, we ask when a Mediterranean-type climate (MTC) originated in Western Australia that might help to explain some of its special plant adaptations to summer drought and heat, mild wet winters and intense summer fires. Periodic drought and fire can be traced back to the Cretaceous in southwestern Australia (SWA) but its seasonality is unknown. Previous estimates of the origin of the MTC in SWA have varied from 30 to 3 million years ago (Ma). An early proposal was that it originated in northwestern Australia 30 Ma and migrated south to its present location for which we find independent support. We collated 47 cases of what is currently known about the time of origin of adaptive responses to summer drought and heat, wet winters and periodic intense fire among flowering plants in SWA. About 15% arose in the 40-30-million-year (My) period, 32% in the 30-20-My period and 47% in the 20-10-My period, suggesting that a MTC may have been widespread in SWA by the mid-Miocene, but there may have been local appearances (proto-MTC) up to 20 My earlier. Uncertainties remain about the location of lineages at various times, the fitness benefits of apparent adaptive traits and their confinement to a MTC, and the significance of the origin versus the onset of diversification of traits. The current dearth of C4 grasses in SWA is consistent with other indications of the absence of a prior history of a summer-dominant rainfall, suggesting that the current MTC arose from a uniform-rainfall climate. Other lines of evidence that might refine these findings include the chemical composition of, and application of geochronometers to, laterites, carbonates and corals that have been used with success elsewhere. We conclude by noting that there may have been a mixture of climates for much of the time, indicated by the persistence of a few rainforest species up to 3

Characterization of three Brazilian bauxites and the corresponding bayer liquors in regard to rare earth and other minor elements

International Nuclear Information System (INIS)

Ikeda Oba, C.A.; Avritscher, W.; Pini, R.A.; Abrao, A.; Chaves, A.P.

1998-01-01

Full text: In this paper the results of chemical analysis of representative Brazilian bauxites are presented and discussed. Analyses were made on original mother rocks, ores, tailings from washing plants, Bayer liquors produced from this ores and also from the red muds. Samples of the ores were submitted to size, magnetic and density separation and these fractions were also analysed. Minor elements of interest assayed were rare earth, gallium and vanadium. Atomic absorption spectroscopy, x-ray fluorescence and emission spectroscopy were applied for the minor elements and also conventional wet chemical analyses mainly for major elements. A special technique for a rapid identification and semi-quantitative analysis of gallium and a permanent file for the results are presented as well. Brazilian bauxites are all of lateritic origin, constituted essentially by gibbsite and formed by intense tropical weathering of different rocks. This paper presents the chemical characterization of three Brazilian bauxites, namely Porto Trombetas, Cataguazes and Pocos de Caldas and the behaviour of their minor elements during the industrial processing in the mines and alumina mills. The grades of rare earths elements, gallium and vanadium show significant variations. This is most probably due to mother rocks characteristics than to bauxitization processes. The review deposits have the following mother rocks: Porto Trombetas Sedimentary - Cataguazes Metamorphic - Pocos de Caldas Alkaline (sienite). The samples from Pocos de Caldas show high grade for La+Ce with an average over 800ppm, Cataguazes has an average of 76 ppm La+Ce and Porto Trombetas 6,5ppm. Gallium grades are higher for Pocos de Caldas (average 135 ppm), followed by Porto Trombetas (62 ppm) and Cataguazes (37ppm). Vanadium grades are higher for Porto Trombetas (243 ppm) then Pocos de Caldas (165 ppm). Pocos de Caldas shows 50% enrichment in Ce in the washed ore and in Porto Trombetas most of the Y goes to the fines (product

Rate of uptake and distribution of Hg in dissolved organic carbon compounds in darkwater ecosystems by ICP-MS and enriched stable isotope spiking

International Nuclear Information System (INIS)

Telmer, Kevin; Dario Bermudez, Rafael; Veiga, Marcello M.; Souza, Terezinha Cid da

2001-01-01

The role of natural organic acids on mercury binding, transportation, net uptake rates and possibly net methylation rates will be evaluated by tracing these processes with isotope enriched mercury and ICP-MS technology. The correlation between dissolved organic matter and Hg in waters is well documented. It appears that organic acids can react with mercury residing in or emitted from different sources such as soils (particularly hydromorphic soils), laterites, natural degassing, forest fires, fuel combustion, gold mining activities, etc. to form soluble Hg-organo-complexes. The formation of these complexes is believed to greatly enhance Hg transport and be an important preliminary step in the formation of Methyl-Hg and biological uptake. The rates of these reactions and the key organic compounds involved in mercury binding will be determined by reacting isotopically-enriched Hg with samples containing a variety of concentrations and types of organic acids and subsequently analysing both reactants and organisms exposed to the reactants (bioassays) for Hg isotopes by ICP-MS. The Hg spike will allow the precise determination of rates of uptake and the most active agents of uptake. Initially, the method will be used to examine total Hg uptake and distribution but if technological limitations are overcome, this same approach can be used to determine net rates of methylation and net MeHg uptake. After the method is validated the experimental design can be altered to test the relative effects of such things as the addition of CO 2 (pH change), or adding a substrate such as Fe-Mn oxyhydroxides. The addition of synthetic materials such as mulched automobile tires, can also be tested with the goal developing a pragmatic remedial method for Hg containment. Ultimately, this research should contribute to an understanding of mercury mobilization, transport and bio-concentration mechanisms, and provide a basis for developing management and treatment strategies. Emphasis will be

A Miocene wave-dominated estuarine system in the Paraíba Basin, northeastern Brazil

Science.gov (United States)

Gandini, Rosana; Rossetti, Dilce de Fátima; Netto, Renata Guimarães; Góes, Ana Maria

2017-11-01

level remained rising through the middle Miocene, the estuarine sedimentation in the study area was cut off, being replaced by a regional unconformity marked by lateritic paleosols. Thus, a relative sea-level fall is recorded in the Paraíba Basin while the eustatic sea level remained rising through the middle Miocene, before its fall in the Tortonian. It follows that other factors, such as tectonics, is proposed to explain the mid-Miocene fall in sea level along the Paraíba coast, while the eustatic sea level was rising.

Planation surfaces as a record of medium to large wavelength deformation: the example of the Lake Albert Rift (Uganda) on the East African Dome

Science.gov (United States)

Brendan, Simon; François, Guillocheau; Cécile, Robin; Jean, Braun; Olivier, Dauteuil; Massimo, Dall'Asta

2016-04-01

African relief is characterized by planation surfaces, some of them of continental scale. These surfaces are slightly deformed according to different wavelengths (x10 km; x100 km, x1000 km) which record both mantle dynamics (very long wavelength, x 1000 km) and lithosphere deformation (long wavelength deformation, x 100 km). Different types of these planation surfaces are recognized: - Etchplains capped by iron-duricrust which correspond to erosional nearly flat weathered surfaces resulting from the growth of laterites under warm and humid conditions. - Pediments which define mechanical erosional surfaces with concave or rectilinear profiles delimited by upslope scarps connected upstream with the upper landforms. We here focused on the Lake Albert Rift at the northern termination of the western branch of the East African Rift System of which the two branches are surimposed on the East-African Dome. Different wavelengths of deformation were characterized based on the 3D mapping of stepped planation surfaces: (1) very long wavelength deformations resulting from the uplift of the East African Dome; (2) long wavelength deformations resulting from the opening of the eastern branch and (3) medium wavelength deformations represented by the uplift of rift shoulders like the Rwenzori Mountains. The paleo-landscape reconstruction of Uganda shows the existence of four generations of landforms dated according to their geometrical relationships with volcanic rocks. A four stepped evolution of the Ugandan landforms is proposed: • 70 - 22 Ma: generation of two weathered planation surfaces (etchplain Uw and Iw). The upper one (Uw) records a very humid period culminating at time of the Early Eocene Climatic Optimum (70-45 Ma). It corresponds to the African Surface. A first uplift of the East African Dome generates a second lower planation surface (Iw) connected to the Atlantic Ocean base level; • 17-2.7 Ma: planation of large pediplains connected to the local base level induced

Metallic elements and metalloids in Boletus luridus, B. magnificus and B. tomentipes mushrooms from polymetallic soils from SW China.

Science.gov (United States)

Falandysz, Jerzy; Zhang, Ji; Wiejak, Anna; Barałkiewicz, Danuta; Hanć, Anetta

2017-08-01

Yunnan Province in China is known for its high biodiversity of mushrooms and a diverse geochemistry of soil bedrock and polymetallic soils, but our knowledge of mineral compositions of mushrooms from Yunnan is scarce. The metallic trace elements, Ag, Ba, Co, Cd, Cs, Cu, Cr, Hg, Li, Mn, Ni, Pb, Rb, Sr, V, Tl, U and Zn, and the metalloids, As and Sb, have been investigated using validated methods with a dynamic reactive cell by mass spectroscopy - inductive coupled plasma and cold vapour - atomic absorption spectroscopy on three popular species of Boletus mushrooms from Southwestern China. The trace mineral profiles in caps and stipes of B. luridus (24 individuals), B. magnificus (29 individuals) and B. tomentipes (38 individuals) have been evaluated. The interspecific differences in the content of several trace elements could be attributed to known differences in the geochemistry of soils in Yunnan, but for copper a difference was observed within species. The mean values of concentrations in composite samples of caps for B. luridus, B. magnificus and B. tomentipes from three to four locations were at the ranges (mgkg -1 dry biomass): Ag (1.3-3.7), As (0.79-53), Ba (4.0-12), Co (0.68-1.2), Cd (0.79-2.2), Cs (0.67-55), Cu (37-77), Cr (5.0-7.6), Hg (2.1-5.4), Li (0.15-0.61), Mn (13-28), Ni (0.86-4.6), Pb (0.59-1.8), Rb (90-120), Sb (0.014-0.088), Sr (0.63-1.6), V (1.4-2.2), Tl (0.017-0.054), U (0.029-0.065) and Zn (130-180). Caps of Boletus mushrooms were richer in Ag, Cu, Hg and Zn than stipes, while other elements were distributed roughly equally between both morphological parts. B. luridus, B. magnificus and B. tomentipes grew in certain sites in Yunnan contained Ag, As, Ba, Cr, Hg, Ni, Sr or V at elevated concentration. A specific geochemistry of the soils type (latosols, lateritic red earths, and red and yellow earths in the Circum-Pacific Mercuriferous Belt of Southwestern China) can explain occurrence of some minerals at greater or elevated amount in mushrooms

Nanoparticles of noble metals in the supergene zone

Science.gov (United States)

Zhmodik, S. M.; Kalinin, Yu. A.; Roslyakov, N. A.; Mironov, A. G.; Mikhlin, Yu. L.; Belyanin, D. K.; Nemirovskaya, N. A.; Spiridonov, A. M.; Nesterenko, G. V.; Airiyants, E. V.; Moroz, T. N.; Bul'bak, T. A.

2012-04-01

Formation of noble metal nanoparticles is related to various geological processes in the supergene zone. Dispersed mineral phases appear during weathering of rocks with active participation of microorganisms, formation of soil, in aqueous medium and atmosphere. Invisible gold and other noble metals are incorporated into oxides, hydroxides, and sulfides, as well as in dispersed organic and inorganic carbonic matter. Sulfide minerals that occur in bedrocks and ores unaltered by exogenic processes and in cementation zone are among the main concentrators of noble metal nanoparticles. The ability of gold particles to disaggregate is well-known and creates problems in technological and analytical practice. When Au and PGE nanoparticles and clusters occur, these problems are augmented because of their unusual reactions and physicochemical properties. The studied gold, magnetite, titanomagnetite and pyrite microspherules from cementation zone and clay minerals of laterites in Republic of Guinea widen the knowledge of their abundance and inferred formation conditions, in particular, in the contemporary supergene zone. Morphology and composition of micrometer-sized Au mineral spherules were studied with SEM and laser microprobe. The newly formed segregations of secondary gold on the surface of its residual grains were also an object of investigation. The character of such overgrowths is the most indicative for nanoparticles. The newly formed Au particles provide evidence for redistribution of ultradispersed gold during weathering. There are serious prerequisites to state that microorganisms substantially control unusual nano-sized microspherical morphology of gold particles in the supergene zone. This is supported by experiments indicating active absorption of gold by microorganisms and direct evidence for participation of Ralstonia metallidurans bacteria in the formation of peculiar corroded bacteriomorphic surface of gold grains. In addition, the areas enriched in carbon

Tracing sediment sources in upstream agricultural catchments: contribution of elemental geochemistry, 87Sr/86Sr ratio and radionuclides measurements

International Nuclear Information System (INIS)

Le-Gall, Marion

2016-01-01

Soil erosion is recognized as one of the main processes of land degradation in agricultural environments. This study develops an original fingerprinting method to examine sediment source contributions in two contrasted agricultural catchments. Several properties were used to trace sediment lithological sources ( 87 Sr/ 86 Sr ratios, elemental concentrations), soil surface and subsurface sources ( 137 Cs) and to quantify their temporal dynamics ( 7 Be, 210 Pb xs ). In the Louroux catchment (24 km 2 , France), representative of drained areas of Northwestern Europe, results showed the dominant contribution of very fine particles (≤2 μm) transiting through the tile drainage system to suspended sediment. Sediment accumulated in the river channel was mainly exported during the two first floods investigated in 2013 whereas the next event was characterized by the transport of sediment eroded from the cultivated soil surface. Mixing models were used, and results indicated that surface sources contributed the majority of sediment deposited in the pond, at the outlet of the catchment. The two lithological sources, discriminated using 87 Sr/ 86 Sr ratios, contributed in similar proportions to downstream pond sediment. In contrast, significant variations were observed since the 1950's. These changes may be related to the progressive implementation of land consolidation schemes within the catchment. Results obtained in the Louroux catchment revealed the potential of 87 Sr/ 86 Sr ratios to trace sediment lithological sources. The methodology was then applied to the larger and steeper Guapore catchment (2000 km 2 , Brazil), exposed to a more erosive climate and characterized by contrasted laterite soils. 87 Sr/ 86 Sr ratios and elements that discriminated the five soil types found in the catchment were incorporated in mixing models. Results showed that the major part of sediment was supplied by soils located in lower catchment parts. This result suggests the higher

Geology of uranium in the Chadron area, Nebraska and South Dakota

Science.gov (United States)

Dunham, Robert Jacob

1961-01-01

The Chadron area covers 375 square miles about 25 miles southeast of the Black Hills. Recurrent mild tectonic activity and erosion on the Chadron arch, a compound anticlinal uplift of regional extent, exposed 1900 feet of Upper Cretaceous rocks, mostly marine shale containing pyrite and organic matter, and 600 feet of Oligocene and Miocene rocks, mostly terrestrial fine-grained sediment containing volcanic ash. Each Cretaceous formation truncated by the sub-Oligocene unconformity is stained yellow and red, leached, kaolinized, and otherwise altered to depths as great as 55 feet. The composition and profile of the altered material indicate lateritic soil; indirect evidence indicates Eocene(?) age. In a belt through the central part of the area, the Brule formation of Oligocene age is a sequence of bedded gypsum, clay, dolomite, and limestone more than 300 feet thick. Uranium in Cretaceous shale in 58 samples averages 0.002 percent, ten times the average for the earths crust. Association with pyrite and organic matter indicates low valency. The uranium probably is syngenetic or nearly so. Uranium in Eocene(?) soil in 43 samples averages 0.054 percent, ranging up to 1.12 percent. The upper part of the soil is depleted in uranium; enriched masses in the basal part of the soil consist of remnants of bedrock shale and are restricted to the highest reaches of the ancient oxidation-reduction interface. The uranium is probably in the from of a low-valent mineral, perhaps uraninite. Modern weathering of Cretaceous shale is capable of releasing as much as 0.780 ppm uranium to water. Eocene(?) weathering probably caused enrichment of the ancient soil through 1) leaching of Cretaceous shale, 2) downward migration of uranyl complex ions, and 3) reduction of hydrogen sulfide at the water table. Uranium minerals occur in the basal 25 feet of the gypsum facies of the Brule formation at the two localities where the gypsum is carbonaceous; 16 samples average 0.066 percent uranium and

Stages of weathering mantle formation from carbonate rocks in the light of rare earth elements (REE) and Sr-Nd-Pb isotopes

Science.gov (United States)

Hissler, Christophe; Stille, Peter

2015-04-01

Weathering mantles are widespread and include lateritic, sandy and kaolinite-rich saprolites and residuals of partially dissolved rocks. These old regolith systems have a complex history of formation and may present a polycyclic evolution due to successive geological and pedogenetic processes that affected the profile. Until now, only few studies highlighted the unusual high content of associated trace elements in weathering mantles originating from carbonate rocks, which have been poorly studied, compared to those developing on magmatic bedrocks. For instance, these enrichments can be up to five times the content of the underlying carbonate rocks. However, these studies also showed that the carbonate bedrock content only partially explains the soil enrichment for all the considered major and trace elements. Up to now, neither soil, nor saprolite formation has to our knowledge been geochemically elucidated. Therefore, the aim of this study was to examine more closely the soil forming dynamics and the relationship of the chemical soil composition to potential sources. REE distribution patterns and Sr-Nd-Pb isotope ratios have been used because they are particularly well suited to identify trace element migration, to recognize origin and mixing processes and, in addition, to decipher possible anthropogenic and/or "natural" atmosphere-derived contributions to the soil. Moreover, leaching experiments have been applied to identify mobile phases in the soil system and to yield information on the stability of trace elements and especially on their behaviour in these Fe-enriched carbonate systems. All these geochemical informations indicate that the cambisol developing on such a typical weathering mantle ("terra fusca") has been formed through weathering of a condensed Bajocian limestone-marl facies. This facies shows compared to average world carbonates important trace element enrichments. Their trace element distribution patterns are similar to those of the soil

CZO perspective in Central Africa : The Lopé watershed, Lopé National Park, Ogooué River basin, Gabon.

Science.gov (United States)

Braun, J. J.; Jeffery, K.; Koumba Pambo, A. F.; Paiz, M. C.; Richter, D., Jr.; John, P.; Jerome, G.

2015-12-01

Critical Zone Observatories (CZO) in equatorial regions are seldom (see e. g. http://www.czen.org/, USA and http://rnbv.ipgp.fr/, France). The equatorial zone of Central Africa is almost free of them with the exception of the CZO of the Upper Nyong river basin (organic-rich river on the lateritic plateau of South Cameroon; SO BVET, http://bvet.omp.obs-mip.fr/). On both sides of the Equator line, the Ogooué River Basin (215,000 km2) stretches on about 80% of the total area of Gabon and drains various geological and morpho-pedological contexts and feeds the sedimentation areas of the Central African passive margin (Guillochaux et al., 2014). The Upper Ogooué (up to Lambaréné) drains the stepped planation surface of the Congo craton while the Lower Ogooué drains Mesozoic and Cenozoic sedimentary terrains. The climate is equatorial (Pmean = 2500 mm/yr; Tmean = 26 °; %humidity > 80%). Continuous hydro-climatic chronicles exist for the period 1953-1974 (managed by ORSTOM, now IRD). The runoff at Lambaréné (92% of the basin area) is very high (714 mm/yr). With a rural density of 1 inhabitant/km2, it is one of the last largely pristine tropical forested ecosystems on the Planet. In addition, the basin will be, in the coming decades, the theatre of important anthropogenic changes (dams, agriculture, mining, urbanisation, …). However, a conservation plan with an ambitious sustainable development policy is set up. This plan articulates the environmental issues related to the emergence of the country. Because of these characteristics, the basin offers ideal conditions for studying the changes in equatorial region of hydro-climate, weathering/erosion regimes and regolith production based on morpho-pedological contexts and associated physical, chemical and biological processes. It is thus germane to launch an integrated CZO initiative at both regional scale and local scale. At the regional scale, we plan to reactivate some of the hydro-climatic stations located on the

Coastal landuse and land cover change and transformations of Kanyakumari coast, India using remote sensing and GIS

Directory of Open Access Journals (Sweden)

S. Kaliraj

2017-12-01

Full Text Available The coastal landuse and land cover features in the South West coast of Kanyakumari are dynamically regulated due to marine and terrestrial processes and often controlling by natural and anthropogenic activities. The primary objective of this study is to estimate the decadal changes and their transformations of landuse and land cover (LULC features under Level II category of USGS-LULC Classification System using Landsat ETM+ and TM images using Maximum Likelihood Classifier (MLC algorithm for the period 2000–2011. The classified LULC features are categorized as beachface land cover, cultivable lands, plantation and shrub vegetation, fallow land, barren land, settlements and built-ups, water bodies, and mining area, etc. The geo-database is prepared for LULC feature class with an attributes of name, location, area and spatial distribution, etc. It shows the larger area in beachface land cover (sandy beaches, foredunes, uplands, Teri dunes (laterite and associated nearshore landforms, plantations, cultivable lands, fallows, and barren lands are converted into built-ups and it increases more than twice in the period of 10 years. Using GIS techniques, the analysis of change detection matrix reveals that the total area of 45.90 km2 in different LULC features periodically shifted or transformed from one state to another one or more states, i.e. the beachface land cover area of 1.24 km2 is encroached for built-ups and 0.63 km2 for placer mining during the decade. Meanwhile, the area of 0.21 km2 in this cover is transformed into wetlands and saltwater bodies. During the past decade, the expansion of area in the built-ups and settlements are directly proportional to the growth of population, which produces severe threat to the coastal resources. Accuracy assessment of classified images shows the overall accuracy is estimated as 81.16% and 77.52% and overall Kappa coeffient statistical values of 0.83 and 0.76 for the year 2000 and 2011 respectively

Timing, tempo and paleoenvironmental influence of Deccan volcanism relative to the KT extinction

Science.gov (United States)

Adatte, Thierry; Keller, Gerta; Schoene, Blair; Khadri, Syed

2015-04-01

Deccan Traps erupted in three main phases with 6% total Deccan volume in phase-1 (base C30n), 80% in phase-2 (C29r) and 14% in phase-3 (C29n). Recent studies indicate that the bulk (80%) of Deccan trap eruptions (Phase-2) occurred over a relatively short time interval in magnetic polarity C29r (Chenet et al., 2008). Moreover, U-Pb zircon geochronology shows that the main Phase 2 began 250 ka before the Cretaceous-Tertiary (KT) mass extinction, suggesting a cause-and-effect relationship (Blair et al., 2015). In India a strong floral response is observed as a direct consequence of volcanic phase-2. In Lameta (infratrappean) sediments preceding the volcanic eruptions, palynoflora are dominated by gymnosperms and angiosperms (Samant and Mohabey, 2005). Shortly after the onset of Deccan phase-2, this floral association was decimated as indicated by a sharp decrease in pollen and spores coupled with the appearance of fungi, which mark increasing stress conditions apparently as a direct result of volcanic activity. The inter-trappean sediments corresponding to the Phases 2 and 3 are characterized by the highest alteration CIA index values suggesting increased acid rains due to SO2 emissions. Closer to the eruption center, the lava flows are generally separated by red weathered horizons known as red boles, marking a quiescent period between two basalt flows. Red boles consist mainly of red silty clays characterized by concentrations of immobile elements such as Al and Fe3+ ions, which provide indirect evidence of a primitive form of paleo-laterite that probably developed during the short periods of weathering between eruptions. There are at least 15 thick red bole layers in C29r below the KT boundary, and all were deposited in phase-2 volcanic eruptions that occurred over a time span of about 250 ky. These short duration exposures are reflected in the mineralogical and geochemical data that indicate rapid weathering (high CIA) but arid conditions. The arid conditions can

Characterization and genesis of waterfalls of the Presidente Figueiredo region, Northeast State of Amazonas, Brazil

Directory of Open Access Journals (Sweden)

AFONSO C. R. NOGUEIRA

2001-06-01

Full Text Available The waterfalls of the Presidente Figueiredo municipality represent a fascinating natural scenery of northeast state of Amazonas, northern Brazil. The falls, generally less than 10m high, are developed on siliciclastic rocks of the Nhamundá (Lower Silurian, and Manacapuru (Upper Silurian - Lower Devonian formations. Morphological and structural analyses of these features indicate that most of them originated through Quaternary neotectonics and are installed in NE-trending normal fault escarpments. Waterfalls also developed within pseudokarstic features, but are less frequent. The origin of the Presidente Figueiredo waterfalls probably goes back to the Neogene, when the region was submitted to laterization processes associated with a humid climate and a dense rainforest. These conditions favored the development of caves in quartzarenites of the Nhamundá Formation. During the Quaternary, the region was subjected to NE-trending normal faulting which displaced laterite layers, rivers and streams giving rise to waterfalls. These climatic and tectonic phenomena promoted intense relief dissection, as indicated by fault escarpment retreat and cave dismantlement, responsible for the present-day morphologic configuration.As cachoeiras da região de Presidente Figueiredo constituem um dos mais fascinantes cenários naturais do nordeste do Estado do Amazonas, norte do Brasil. As quedas, geralmente com menos de 10m de altura, são desenvolvidas em rochas siliciclásticas das formações Nhamundá (Siluriano inferior e Manacapuru (Siluriano superior-Devoniano inferior. Os estudos morfológico e estrutural dessas feições indicam que a maioria dessas quedas de água originaram-se por neotectônica quaternária e encontram-se instaladas em escarpas de falhas normais NE-SW. Ocorrem, ainda, com menor freqüência, cachoeiras evoluídas a partir de feições pseudocársticas. A origem das cachoeiras de Presidente Figueiredo provavelmente remonta ao Ne

Environmental transformation and distribution of mercury released from gold mining and its implications on human health in Tanzania, studied by nuclear techniques

International Nuclear Information System (INIS)

Ikingura, Justinian R.

2002-01-01

fall of mercury levels in the air away from the source of emission. The presence of the mercury gradient in the lichens around the mine, make the lichens suitable as a bioindicator for the assessment of air mercury pollution from gold-ore processing operations. Results of the laboratory experiments on mercury absorption by laterite and bauxite and mercury transformation and uptake by fish in an aquatic system contaminated by gold-ore tailings are also discussed. (author)

Characterization of diagenetic siderites formed in recent and ancient ferruginous sediments of Lake Towuti, Indonesia.

Science.gov (United States)

Vuillemin, Aurele; Kallmeyer, Jens; Wagner, Dirk; Kemnitz, Helga; Wirth, Richard; Luecke, Andreas; Mayr, Christoph

2016-04-01

Authigenic minerals in lacustrine settings can be formed in the water column and within the sediment, abiotically and/or triggered by biological activity. Such minerals have been used as paleosalinity and paleoproductivity proxies, reflecting trophic state, and/or early diagenetic conditions. They have also been considered as potential biosignatures of past and present microbial activity. Here we present a study from Lake Towuti, a deep tectonic basin in Sulawesi, Indonesia. Its geographic position makes it a prime location to record paleoclimatic changes in the tropical Western Pacific warm pool in its sedimentary sequence. The ultramafic rocks and surrounding lateritic soils in the catchment area supply considerable amounts of iron and other metals to the lake. These elements further restrain primary productivity along with the development of specific microbial metabolic pathways involved in early diagenesis. Lake Towuti is stratified with anoxic conditions below 130 m, allowing metal reduction processes to take place in the hypolimnion. The extreme scarcity of sulphate and nitrate/nitrite make Lake Towuti's bottom waters a modern analogue for the Archaean Ocean. It was therefore chosen as a drilling target by the International Continental Drilling Program (ICDP). In May to July 2015, the Towuti Drilling Project recovered a total >1000 m of sediment core from three drilling sites, including a 114 m long core drilled with a contamination tracer dedicated to geomicrobiological studies. Heavy mineral fractions were extracted from core catcher samples and siderite crystals (FeCO3) were selected from different depths. Characterization of their habitus was achieved via SEM and TEM imaging. Preliminary results show that siderites grow from amorphous into nanocrystalline phases and form twinned aggregates developing into mosaic monocrystals with depth. Gradual filling of vugs and microporosity were observed along with inclusions of magnetite nanocrystals. Work in

莫西沙星和左氧氟沙星致急性肾小管间质肾病%Acute interstitial nephritis caused by moxifloxacin and levofloxacin

Institute of Scientific and Technical Information of China (English)

李颖慧; 杭永付; 梁雁

2016-01-01

A 31-year-old male patient received an oral moxifloxacin 0. 4 g once daily for respiratory infection and after 3 days of treatment,his symptoms were not improved and appeared urine decrease. Moxifloxacin was stopped and changed into levofloxacin 0. 2 g twice daily by mouth. After 8 days of treatment,the patient's symptoms was not improved apparently and appeared urinary protein( + ),5-10 erythrocytes/ high magnification( HP),3-5 white blood cells/ HP,serum creatinine 419 μmol/ L. Renal biopsy showed acute tubular interstitial nephropathy. Drug-induced acute interstitial nephritis-induced by moxifloxacin and levofloxacin was considered. Levofloxacin was stopped and an IV infusion of methylpred-nisolone 250 mg once daily was given,and 3 days later,it was changed into oral prednison 40 mg once daily. After 7 days of treatment,the patient' s blood creatinine was 168 mol/ L,urea 13. 6 mmol/ L, glomerular filtration rate 45. 8 ml/ min/ 1. 73 m2 . The patient got better and was discharged. At 2 months of follow up,the patient's blood creatinine was 119 μmol/ L and urea was 6. 2 mmol/ L.%1例31岁男性患者因呼吸道感染给予莫西沙星0.4 g、1次/ d 口服，用药3 d 病情无改善并出现尿量减少；换用左氧氟沙星0.2 g、2次/ d 口服，用药8 d 病情仍无明显好转，且出现尿蛋白（+），5~10个红细胞/ HP，3~5个白细胞/ HP，Scr 419μmol/ L。肾活检示急性肾小管间质肾病。考虑可能为莫西沙星和左氧氟沙星引起的急性间质性肾炎。停用左氧氟沙星，给予甲泼尼龙250 mg、1次/ d 静脉滴注；3 d 后改为泼尼松40 mg、1次/ d 口服。治疗7 d 后患者 Scr 降至168μmol/ L，尿素13.6 mmol/ L，eGFR 45.8 ml·min-1·1.73 m-2。2个月后复查，患者 Scr 119μmol/ L，尿素6.2 mmol/ L。

Detrital and early chemical remanent magnetization in redbeds and their rock magnetic signature: Zicapa Formation, southern Mexico

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Sierra-Rojas, Maria Isabel; Molina-Garza, Roberto Stanley

2018-06-01

observations. The particle size of haematite ranges from approximately 10 to 300 μm for detrital haematite (martite, specularite and laterite), and from ca. 0.2 to 1 μm for pigmentary haematite flakes. The IRM of these rocks can be modelled with components of low coercivity (H1/2 between 5 and 10 mT interpreted as detrital magnetite), and components of a wide coercivity range (prevailing H1/2 from ˜400 to 600 mT interpreted as haematite). Hysteresis ratios show a systematic correlation with demagnetization behaviour, with lower Hcr/Hc values and higher Mrs/Ms values for samples with a dominant chemical component, than form samples with a significant (>40 per cent) depositional component.

Phanerozoic burial, uplift and denudation of the Equatorial Atlantic margin of South America

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Japsen, Peter; Bonow, Johan M.; Green, Paul F.; dall'Asta, Massimo; Roig, Jean-Yves; Theveniaut, Hervé

2017-04-01

onshore margin. References Green, Lidmar-Bergström, Japsen, Bonow & Chalmers 2013: Stratigraphic landscape analysis, thermochronology and the episodic development of elevated passive continental margins. GEUS Bulletin. Japsen, Green, Bonow & Erlström 2016: Episodic burial and exhumation of the southern Baltic Shield: Epeirogenic uplifts during and after break-up of Pangea. Gondwana Research. Japsen, Bonow, Green, Cobbold, Chiossi et al. 2012: Episodic burial and exhumation history of NE Brazil after opening of the South Atlantic. GSA Bulletin. Sapin, Davaux, dall'Asta et al. 2016: Post-rift subsidence of the French Guiana hyper-oblique margin: from rift-inherited subsidence to Amazon deposition effect. Geol. Soc. Spec. Publ. Theveniaut & Freyssinet 2002: Timing of lateritization on the Guiana Shield: synthesis of paleomagnetic results from French Guiana and Suriname. 3 x Palaeo.

Mineralogical and geochemical characteristics of the Noamundi-Koira basin iron ore deposits (India)

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Mirza, Azimuddin; Alvi, Shabbar Habib; Ilbeyli, Nurdane

2015-04-01

India is one of the richest sources of iron ore deposits in the world; and one of them is located in the Noamundi-Koira basin, Singhbhum-Orissa craton. The geological comparative studies of banded iron formation (BIF) and associated iron ores of Noamundi-Koira iron ore deposits, belonging to the iron ore group in eastern India, focus on the study of mineralogy and major elemental compositions along with the geological evaluation of different iron ores. The basement of the Singhbhum-Orissa craton is metasedimentary rocks which can be traced in a broadly elliptical pattern of granitoids, surrounded by metasediments and metavolcanics of Greenstone Belt association. The Singhbhum granitoid is intrusive into these old rocks and to younger, mid Archaean metasediments, including iron formations, schists and metaquartzites and siliciclastics of the Precambrian Iron Ore Group (Saha et al., 1994; Sharma, 1994). The iron ore of Noamundi-Koira can be divided into seven categories (Van Schalkwyk and Beukes 1986). They are massive, hard laminated, soft laminated, martite-goethite, powdery blue dust and lateritic ore. Although it is more or less accepted that the parent rock of iron ore is banded hematite jasper (BHJ), the presence of disseminated martite in BHJ suggests that the magnetite of protore was converted to martite. In the study area, possible genesis of high-grade hematite ore could have occurred in two steps. In the first stage, shallow, meteoric fluids affect primary, unaltered BIF by simultaneously oxidizing magnetite to martite and replacing quartz with hydrous iron oxides. In the second stage of supergene processes, deep burial upgrades the hydrous iron oxides to microplaty hematite. Removal of silica from BIF and successive precipitation of iron resulted in the formation of martite- goethite ore. Soft laminated ores were formed where precipitation of iron was partial or absent. The leached out space remains with time and the interstitial space is generally filled

Cobalt

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Slack, John F.; Kimball, Bryn E.; Shedd, Kim B.; Schulz, Klaus J.; DeYoung,, John H.; Seal, Robert R.; Bradley, Dwight C.

2017-12-19

Cobalt is a silvery gray metal that has diverse uses based on certain key properties, including ferromagnetism, hardness and wear-resistance when alloyed with other metals, low thermal and electrical conductivity, high melting point, multiple valences, and production of intense blue colors when combined with silica. Cobalt is used mostly in cathodes in rechargeable batteries and in superalloys for turbine engines in jet aircraft. Annual global cobalt consumption was approximately 75,000 metric tons in 2011; China, Japan, and the United States (in order of consumption amount) were the top three cobalt-consuming countries. In 2011, approximately 109,000 metric tons of recoverable cobalt was produced in ores, concentrates, and intermediate products from cobalt, copper, nickel, platinum-group-element (PGE), and zinc operations. The Democratic Republic of the Congo (Congo [Kinshasa]) was the principal source of mined cobalt globally (55 percent). The United States produced a negligible amount of byproduct cobalt as an intermediate product from a PGE mining and refining operation in southeastern Montana; no U.S. production was from mines in which cobalt was the principal commodity. China was the leading refiner of cobalt, and much of its production came from cobalt ores, concentrates, and partially refined materials imported from Congo (Kinshasa).The mineralogy of cobalt deposits is diverse and includes both primary (hypogene) and secondary (supergene) phases. Principal terrestrial (land-based) deposit types, which represent most of world’s cobalt mine production, include primary magmatic Ni-Cu(-Co-PGE) sulfides, primary and secondary stratiform sediment-hosted Cu-Co sulfides and oxides, and secondary Ni-Co laterites. Seven additional terrestrial deposit types are described in this chapter. The total terrestrial cobalt resource (reserves plus other resources) plus past production, where available, is calculated to be 25.5 million metric tons. Additional resources of

Effect of a Quaternary Meteoroid Impact in Indo-China on the Surface Sedimentary Record

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Carling, Paul; Songtham, Wickanet; Tada, Riuji; Tada, Toshihiro; Duangkrayon, Jaa

2017-04-01

to blast and are burnt. Fossil evidence for the local extirpations of Quaternary mammals within the region might also be related to the impact event. Tektites occur at the same level as occupation horizons of Palaeolithic people such that the impact would have had direct effects on hominins. The stratigraphy includes: erosional antidunes, blast-induced debris flow incorporating tektites, catastrophically-broken laterite pavements and mud layers with reversed magnetism. Sedimentological evidence in favour of impact includes: the presence of delicate thin translucent-tektites that must be in situ from initial fallout as reworking would destroy them, graded spherule distributions, highly-stressed quartz grains and microtektites. Grain size data, including X-ray and CT-scanning analysis, can be used to support the impact hypothesis but alone these data are not conclusive. XRD data is inconclusive. On balance the stratigraphy and sedimentology support the notion that the sediments represent the distal effects of a meteorite in the region.

Groundwater Quality Assessment in the Upper East Region of Ghana

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Apambire, W. B.

2001-05-01

concentrations of Al are associated with shallow wells and ponds. There is a highly positive correlation (r = +1) between Fe and Al, suggesting that dissolution of weathered lateritic material (e.g., Fe oxides, gibbsite, etc.) is the common source for these elements. Manganese concentrations are generally within acceptable limits, except for 11 wells that have concentrations above the guideline limit of 0.1 mg/L. These anomalous concentrations may be associated with manganiferous deposits in the study area. A majority of the samples contain very low concentrations of the trace elements Zn, Pb, Cd, Cr, As and Se; however, the highest concentrations occur in areas where small-scale mining is practiced.

Soil microbial population and nitrogen fixation in peanut under fly ash and sewage sludge

International Nuclear Information System (INIS)

Sarkar, S.; Khan, A.R.

2002-06-01

such as C, N, S, and P in the biosphere (Wong and Wong, 1986). Addition of such wastes to agricultural lands is likely to alter the nutrient cycling processes particularly for leguminous crops, where nodulation, N 2 fixation and N uptake is mainly governed by a group of microorganisms (McGrath et al., 1988). It is therefore imperative to study the effect of different doses and combination of wastes on changes in microbial population and its impact on overall performance of a crop. The objective of this study is thus, to investigate the implications of industrial wastes (Fly Ash) and urban sewage sludge (treated City Waste) application at different rates and frequencies of application on the total soil microbial population, Rhizobium population, nodulation, N-uptake, N-accumulation and yield of peanut crop in lateritic sandy loam soil of eastern India

Bauxite to eclogite: Evidence for late Permian supracontinental subduction at the Red River shear zone, northern Vietnam

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Nakano, Nobuhiko; Osanai, Yasuhito; Nam, Nguyen Van; Tri, Tran Van

2018-03-01

We have investigated the geological processes recorded in aluminous granulites from the Red River shear zone in northern Vietnam using mineral and whole-rock chemistries, fluid inclusions, metamorphic pressure-temperature paths, and geochronology. The granulites are extremely rich in Al2O3 (36.3-50.9 wt%), TiO2, and total Fe2O3, and poor in SiO2 (7.9-24.1 wt%), MgO, CaO, Na2O, and K2O. The granulites are enriched in high-field-strength elements and rare earth elements, and severely depleted in large-ion lithophile elements. These features strongly suggest the protolith was lateritic bauxite. Moreover, the other elemental concentrations and the Zr/Ti ratios point to basaltic rock as the precursor of the bauxite. Some of the aluminous granulites contain high-pressure mineral inclusions of kyanite, staurolite, siderite, and rutile, none of which are observed in the matrix. Abundant primary carbonic fluid inclusions are observed in garnet, corundum, and staurolite, but are rare in quartz and zircon. The average densities of fluid inclusions in garnet, corundum, staurolite, quartz, and zircon are 1.00 ± 0.06, 1.07 ± 0.04, 1.09 ± 0.03, 0.29 ± 0.07, and 1.15 ± 0.05 g/cm3, respectively. The mineral features not only in the matrix and but also in garnet from all rock types, isochemical phase diagrams obtained for each bulk rock composition, and Zr-in-rutile thermometry indicate an early eclogite-facies metamorphism ( 2.5 GPa at 650 °C) and a subsequent nearly isothermal decompression. Zircons yield a wide range of U-Pb ages from 265 to 36 Ma, whereas the dark luminescent cores of the zircons, which contain high-density CO2 inclusions, yield a concordia age of 257 ± 8 Ma. These observations suggest that the dark luminescent zircon cores were formed at the same time as the garnet, corundum, and staurolite that contain high-density CO2 fluid inclusions. Based on the carbonic fluid inclusion isochore and the densities as well as calculated phase diagram, the concordia

The influence of vegetation cover and soil physical properties on deflagration of shallow landslides - Nova Friburgo, RJ / Brazil

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de Oliveira Marques, Maria Clara; Silva, Roberta; Fraga, Joana; Luiza Coelho Netto, Ana; Mululo Sato, Anderson

2017-04-01

water in the depths in which they are terminal increasing the pore water pressure. Soil saturation in this area also occurred in heavy rains, but more deeply due to the rapid movement and redirection of water in depth by tree roots. This process was also responsible for the higher subsurface flows found in the forest, that is, the greater aggregation of the soil, the existence of interconnected macropores, ducts and roots facilitate the transmission of water in depth. Associated with the high rainfall and high relative humidity, these vegetation favoured the formation of saturation zones and increased pore pressures of the water, causing landslides on lands between 0.5 m and 2.0 m. The results of hydraulic conductivity show that the difference (lateritic = 10-4 cm/s; saprolitic = 10-5 cm/s) between the layers of the soil can generate zones of hydraulic discontinuity in extreme rainfall events, which would justify the predominance of shallow translational landslides at these same depths.

Tectonics and paleogeography of the Marajó Basin, northern Brazil

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JOÃO B. S. COSTA

2002-09-01

Full Text Available The Marajó Basin area presents geologic and geomorphologic features chiefly due to the Mesozoic extension and post-Miocene neotectonics. The extension event with an Early and a Late Cretaceous phases originated four sub-basins that constitutes the Marajó Basin, with a thick continental clastic sequence showing marine influence. NW and NNW normal faults and NE and ENE strike-slip faults controlled the basin geometry. The extension, related to the Equatorial Atlantic opening, propagated into the continent along crustal weakness zones of the Precambrian Tumucumaque, Amapá and Araguaia orogenic belts. The neotectonic event is a strike-slip regime which developed transtensional basins filled in by Upper Tertiary shallow marine (Pirabas Formation and transitional sequences (Barreiras Group, followed by Quaternary fluvial deposits and transitional sequences derived from the Amazon and Tocantins rivers and the Marajoara estuary. The current landscape has a typical estuarine morphology. The coast morphology presents sea-cliffs on transitional Upper Tertiary sequences, while inwards dominate hills sustained by Mid-Pleistocene lateritic crust, with a flat erosive surface at 70 m. In the eastern Marajó Island several generations of paleochannels associated with fluvial-estuarine sequences are recognized, while a fluvial-marine plain is widespread on its western side.A área da Bacia do Marajó apresenta feições geológicas e geomorfológicas devidas principamente à distensão Mesozóica e à neotectônica pós-miocênica. O evento de distensão, com fases do Cretáceo Inferior e Superior, originou quatro sub-bacias que contituem a Bacia do Marajó, com uma espessa seqüência clástica continental mostrando influência marinha. Falhas normais NW e NNW e direcionais NE e ENE controlaram a geometria da bacia. A distensão, relacionada com a abertura do Atlântico Equatorial, propagou-se continente adentro ao longo de zonas de fraqueza crustal dos

Origin of enormous trace metal enrichments in weathering mantles of Jurassic carbonates: evidence from Sr, Nd and Pb isotopes

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Hissler, C.; Stille, P.; Juilleret, J.; Iffly, J.; Perrone, T.; Morvan, G.

2013-12-01

Weathering mantels are widespread worldwide and include lateritic, sandy and kaolinite-rich saprolites and residuals of partially dissolved carbonate rocks. These old regolith systems have a complex history of formation and may present a polycyclic evolution due to successive geological and pedogenetic processes that affected the profile. Until now, only few studies highlighted the unusual content of associated trace elements in this type of weathering mantle. For instance, these enrichments can represent about five times the content of the underlying Bajocian to Oxfordian limestone/marl complexes, which have been relatively poorly studied compared to weathering mantle developed on magmatic bedrocks. Up to now, neither soil, nor saprolite formation has to our knowledge been geochemically elucidated. Therefore, the aim of this study was to examine more closely the soil forming dynamics and the relationship of the chemical soil composition to potential sources (saprolite, Bajocian silty marls and limestones, atmospheric particles deposition...). Of special interest has also been the origin of trace metals and the processes causing their enrichments. Especially Rare Earth Element (REE) distribution patterns and Sr, Nd and Pb isotope ratios are particularly well suited to identify trace element migration, to recognize origin and mixing processes and, in addition, to decipher possible anthropogenic and/or "natural" atmosphere-derived contributions to the soil. Moreover, leaching experiments shall help to identify mobile phases in the soil system. This may inform on the stability of trace elements and especially on their behaviour in these Fe-enriched carbonate systems. Trace metal migration and enrichments were studied on a cambisol developing on an underlying Jurassic limestone. The base is strongly enriched among others in rare earth elements (ΣREE: 2640ppm) or redox-sensitive elements such as Fe (44 wt.%), V (920ppm), Cr (700ppm), Zn (550ppm), As (260ppm), Co (45ppm

Sedimentology and arsenic pollution in the Bengal Basin: insight into arsenic occurrence and subsurface geology.

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Hills, Andrew; McArthur, John

2014-05-01

The Bengal delta system is a geologically recent feature overlying a deeply incised palaeo-surface formed during the Last Glacial Maximum. This surface is a series of terraces and valleys created by river incision (Goodbred & Kuehl 2003). The terraces were weathered, forming a thin, indurated laterite deposit (Goodbred & Kuehl 2000) at depths greater than 50 m. McArthur et al. (2008) define this as a palaeosol and have identified it at depths greater than 30 m though out Bangladesh and West Bengal. It has been observed that arsenic concentrations at these sites are lower than the rest of the delta. It has been assumed that the surface morphology at sites where there is a palaeosol are similar and can therefore be characterised by remote sensing, in the form of Google Earth images. Sites were selected in Bangladesh and West Bengal, from work by McArthur et al. (2011); Hoque et al. (2012), where groundwater chemistry and sedimentology data are available making it possible to determine if the subsurface is a palaeo-channel or palaeo-interfluve. Arsenic concentration data have been inputted into Google Earth and the palaeo-channels marked where the arsenic concentration is greater than 10 µg/L, and palaeo-interfluves where arsenic concentration is less than 10 µg/L. The surface morphologies in these domains have been examined for similarities, and it was shown that avulsion scars and abandoned river channels are found where arsenic concentrations are greater than 10 µg/L. Conversely the surrounding areas that are devoid of channel scars have arsenic concentrations less than 10 µg/L. Using the correlation between avulsion features being representative of palaeo-channels and high arsenic concentrations, sites were selected that had a similar surface morphology to the type localities. A comparison of these images and arsenic concentrations showed that the postulate is valid for over 80 percent of cases. Where this is not valid, this could indicate that the subsurface

Ground-water geology of Kordofan Province, Sudan

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Rodis, Harry G.; Hassan, Abdulla; Wahadan, Lutfi

1968-01-01

For much of Kordofan Province, surface-water supplies collected and stored in hafirs, fulas, and tebeldi trees are almost completely appropriated for present needs, and water from wells must serve as the base for future economic and cultural development. This report describes the results of a reconnaissance hydrogeologic investigation of the Province and the nature and distribution of the ground-water resources with respect to their availability for development. Kordofan Province, in central Sudan, lies within the White Nile-Nile River drainage basin. The land surface is largely a plain of low relief; jebels (hills) occur sporadically, and sandy soils are common in most areas except in the south where clayey soils predominate. Seasonal rainfall, ranging from less than 100 millimeters in the north to about 800 millimeters in the south, occurs almost entirely during the summer months, but little runoff ever reaches the Nile or White Nile Rivers. The rocks beneath the surficial depsits (Pleistocene to Recent) in the Province comprise the basement complex (Precambrian), Nawa Series (upper Paleozoic), Nubian Series (Mesozoic), laterite (lower to middle Tertiary), and the Umm Ruwaba Series (Pliocene to Pleistocene). Perennial ground-water supplies in the Province are found chiefly in five hydrologic units, each having distinct geologic or hydrologic characteristics. These units occur in Nubian or Umm Ruwaba strata or both, and the sandstone and conglomerate beds form the :principal aquifers. The water is generally under slight artesian head, and the upper surface of the zone of saturation ranges from about 50 meters to 160 meters below land surface. The surficial deposits and basement rocks are generally poor sources of ground water in most of the Province. Supplies from such sources are commonly temporary and may dissipate entirely during the dry season. Locally, however, perennial supplies are obtained from the surficial deposits and from the basement rocks. Generally

Geochemistry of Selected Coal Samples from Sumatra, Kalimantan, Sulawesi, and Papua, Indonesia

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Belkin, Harvey E.; Tewalt, Susan J.

2007-01-01

Introduction Indonesia is an archipelago of more than 17,000 islands that stretches astride the equator for about 5,200 km in southeast Asia (figure 1) and includes major Cenozoic volcano-plutonic arcs, active volcanoes, and various related onshore and offshore basins. These magmatic arcs have extensive Cu and Au mineralization that has generated much exploration and mining in the last 50 years. Although Au and Ag have been mined in Indonesia for over 1000 years (van Leeuwen, 1994), it was not until the middle of the nineteenth century that the Dutch explored and developed major Sn and minor Au, Ag, Ni, bauxite, and coal resources. The metallogeny of Indonesia includes Au-rich porphyry Cu, porphyry Mo, skarn Cu-Au, sedimentary-rock hosted Au, epithermal Au, laterite Ni, and diamond deposits. For example, the Grasberg deposit in Papua has the world's largest gold reserves and the third-largest copper reserves (Sillitoe, 1994). Coal mining in Indonesia also has had a long history beginning with the initial production in 1849 in the Mahakam coal field near Pengaron, East Kalimantan; in 1891 in the Ombilin area, Sumatra, (van Leeuwen, 1994); and in South Sumatra in 1919 at the Bukit Asam mine (Soehandojo, 1989). Total production from deposits in Sumatra and Kalimantan, from the 19thth century to World War II, amounted to 40 million metric tons (Mt). After World War II, production declined due to various factors including politics and a boom in the world-wide oil economy. Active exploration and increased mining began again in the 1980's mainly through a change in Indonesian government policy of collaboration with foreign companies and the global oil crises (Prijono, 1989). This recent coal revival (van Leeuwen, 1994) has lead Indonesia to become the largest exporter of thermal (steam) coal and the second largest combined thermal and metallurgical (coking) coal exporter in the world market (Fairhead and others, 2006). The exported coal is desirable as it is low sulfur

Hydrology and Soil Erosion in Tropical Rainforests and Pasture Lands on the Atherton Tablelands, North Queensland, Australia - a rainfall simulator study

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Joanne, Joanne; Ciesiolka, Cyril

2010-05-01

observed to be part of a drainage network and which were typical of the surrounding hillslopes. A 13 m long by 2 m wide portable rainfall simulator was used to produce rainfall associated with high intensity events. The simulator consisted of six A-frame modules with spray nozzles (equipped with pressure gauges) that operated in an oscillating movement. Rainfall from the simulator was measured using seven dynamically calibrated pluviometers (~0.1mm/tip) and 26 rain gauges (100mm diameter, muslin covered). Runoff volume was recorded using a tipping bucket mechanism. Samples were collected at three minute intervals and used to calculate soil loss using standard methods. At sites where there was a high rate of infiltration a catena effect on runoff could be discerned. Highest runoff volumes tended to be generated on the midslope, rectilinear segments of the hillslope. However some of the sites exhibited effects from indurated laterite layers, exfiltration areas, and small areas of unweathered basalt veneered by a surface ferrasol. All sites had high levels of vegetative cover but large differences in biomass. While runoff and soil erosion were not significantly correlated with vegetative cover, a useful relationship was found when cover was multiplied by biomass. The rate of soil loss from intensive dairying was less than from the intensive beef grazing sites and cattle tracks. However, because deposition from these point sources occurred it became difficult to verify whether contributions from overland flow to the stream were significant. Observations of farm dam overflows near to the simulation sites confirmed the significant subsurface flows that diluted sediment concentrations in the local waterways. Overall, the results indicated that to reduce sediment loss farms must be designed and managed according to landscape features. In order to better understand runoff and sediment delivery it would be necessary to measure volumes and rates through a 'nested' catchment approach

Kinetic stable Cr isotopic fractionation between aqueous Cr(III)-Cl-H2O complexes at 25 °C: Implications for Cr(III) mobility and isotopic variations in modern and ancient natural systems

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Babechuk, Michael G.; Kleinhanns, Ilka C.; Reitter, Elmar; Schoenberg, Ronny

2018-02-01

dissolution of two Cr(III)-Cl solids (dried NIST SRM979 standard and commercial CrCl3·6H2O salt) in 0.01 M HCl (pH ≈ 2). The ε53/52Cr(CrCl2+/CrCl2+) for the CrCl2+ to CrCl2+ reaction is -0.19‰ (SRM979) and -0.38‰ (salt) and the ε53/52Cr(Cr3+/CrCl2+) for the CrCl2+ to Cr3+ reaction is consistent for both experiments at -0.49‰ (SRM979) and -0.51‰ (salt). Experiments where SRM979 is dissolved in 0.1 and 1 M HCl for a longer aging period provide preliminary evidence that the Cr3+/CrCl2+ Cr(III) isotopic fractionation scales with HCl concentration (transformation rate). Chromium(III) dissolved in 6 M HCl and aged 5 months still yields an inter-species Cr isotope distribution that is apparently inherited from kinetic effects (light Cr isotopes in Cr3+), attesting to the slow development of inter-species isotopic equilibrium, which instead predicts progressively heavier Cr isotopes from CrCl2+ to CrCl2+ to Cr3+. The kinetic Cr(III) isotopic fractionation documented herein is proposed to be relevant to understanding systems where aqueous Cr(III)-Cl species may be temporarily stable (e.g., metamorphic and hydrothermal systems or lateritic weathering). Further, the complexation of Cr(III) with other ligands (e.g., CO32-, organics), combined with additional kinetic effects of Cr(III) potentially occurring in soils or sediment, must be explored prior to establishing the significance of empirical stable Cr isotope signatures in marine and continental environments. Further understanding of non-redox effects may lead to stable Cr isotopes developing as a proxy for system pH or ligand chemistry.

The limitations of seedling growth and drought tolerance to novel soil substrates in arid systems: Implications for restoration success

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Bateman, Amber; Lewandrowski, Wolfgang; Stevens, Jason; Muñoz-Rojas, Miriam

2016-04-01

resulting in seedling mortality at less negative soil water potential. Finally, no significant differences in drought tolerance were observed between the two leaf stages across the four species tested. Analysis of plant desiccation curves found the advanced leaf stage to be less tolerant of drought as shown by a decrease in soil water potential at the time of stomatal closure. Species possess a range of morphological traits, some of which are associated with drought tolerance. However, these traits on their own may not be main drivers for drought resilience and other factors play a role, for example soil nutrient availability. Materials tested in this study that may be available to create novel restoration substrates hinder plant growth but not necessarily plant responses to drought. These findings go a long way to defining some of the limitations of seedling growth and the degree of drought tolerance which will assist in the management of post-mining restoration. References James, J.J., Sheley, R.L., Erickson,T., Rollins, K.S., Taylor, M.H., Dixon, K.W. (2013) A systems approach to restoring degraded drylands. Journal of Applied Ecology 50:730-739. Machado, N. A. M., Leite, M. G. P., Figueiredo, M. A., Kozovits, A. R. (2013) Growing Ereman-thus erythropappus in crushed laterite: A promising alternative to topsoil for baux¬ite-mine revegetation. Journal of Environmental Management 129: 149-156. Muñoz-Rojas, M., Erickson, T., Merritt, D., Dixon, K. (2014) Optimising post-mining soil conditions to maximise restoration success in a biodiverse semiarid environment. Geophysical Research. Abstracts Vol. 16, EGU2014-2069-1, EGU General Assembly. Muñoz-Rojas, M., Erickson, T., Merritt, D., Dixon, K. (2015) Applying soil science for restoration of post mining degraded landscapes in semi-arid Australia: challenges and opportunities. Geophysical Research. Abstracts Vol. 17, EGU2015-3967-1, EGU General Assembly.

Paleoenvironments, Evolution, and Geomicrobiology in a Tropical Pacific Lake: The Lake Towuti Drilling Project (TOWUTI)

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Vogel, Hendrik; Russell, James M.; Bijaksana, Satria; Crowe, Sean; Fowle, David; Haffner, Douglas; King, John; Marwoto, Ristiyanti; Melles, Martin; von Rintelen, Thomas; Stevenson, Janelle; Watkinson, Ian; Wattrus, Nigel

2014-05-01

Lake Towuti (2.5°S, 121°E) is a, 560 km2, 200-m deep tectonic lake at the downstream end of the Malili lake system, a set of five, ancient (1-2 MYr) tectonic lakes in central Sulawesi, Indonesia. Lake Towuti's location in central Indonesia provides a unique opportunity to reconstruct long-term paleoclimate change in a crucially important yet understudied region- the Indo-Pacific warm pool (IPWP), heart of the El Niño-Southern Oscillation. The Malili Lakes have extraordinarily high rates of floral and faunal endemism, and the lakes are surrounded by one of the most diverse tropical forests on Earth. Drilling in Lake Towuti will identify the age and origin of the lake and the environmental and climatic context that shaped the evolution of this unique lacustrine and terrestrial ecosystem. The ultramafic (ophiolitic) rocks and lateritic soils surrounding Lake Towuti provide metal substrates that feed a diverse, exotic microbial community, analogous to the microbial ecosystems that operated in the Archean Oceans. Drill core will provide unique insight into long-term changes in this ecosystem, as well as microbial processes operating at depth in the sediment column. High-resolution seismic reflection data (CHIRP and airgun) combined with numerous long sediment piston cores collected from 2007-2013 demonstrate the enormous promise of Lake Towuti for an ICDP drilling campaign. Well-stratified sequences of up to 150 m thickness, uninterrupted by unconformities or erosional truncation, are present in multiple sub-basins within Towuti, providing ideal sites for long-term environmental, climatic, and limnological reconstructions. Multiproxy analyses of our piston cores document a continuous and detailed record of moisture balance variations in Lake Towuti during the past 60 kyr BP. In detail our datasets show that wet conditions and rainforest ecosystems in central Indonesia persisted during Marine Isotope Stage 3 (MIS3) and the Holocene, and were interrupted by severe

Vanadium

Science.gov (United States)

Kelley, Karen D.; Scott, Clinton T.; Polyak, Désirée E.; Kimball, Bryn E.; Schulz, Klaus J.; DeYoung,, John H.; Seal, Robert R.; Bradley, Dwight C.

2017-12-19

sands, and oil shales may be important future sources.Vanadium occurs in one of four oxidation states in nature: +2, +3, +4, and +5. The V3+ ion has an octahedral radius that is almost identical to that of (Fe3+) and (Al3+) and, therefore, it substitutes in ferromagnesian minerals. During weathering, much of the vanadium may partition into newly formed clay minerals, and it either remains in the +3 valence state or oxidizes to the +4 valence state, both of which are relatively insoluble. If erosion is insignificant but chemical leaching is intense, the residual material may be enriched in vanadium, as are some bauxites and laterites. During the weathering of igneous, residual, or sedimentary rocks, some vanadium oxidizes to the +5 valence state, especially in the intensive oxidizing conditions that are characteristic of arid climates.The average contents of vanadium in the environment are as follows: soils [10 to 500 parts per million (ppm)]; streams and rivers [0.2 to 2.9 parts per billion (ppb)]; and coastal seawater (0.3 to 2.8 ppb). Concentrations of vanadium in soils (548 to 7,160 ppm) collected near vanadium mines in China, the Czech Republic, and South Africa are many times greater than natural concentrations in soils. Additionally, if deposits contain sulfide minerals such as chalcocite, pyrite, and sphalerite, high levels of acidity may be present if sulfide dissolution is not balanced by the presence of acid-neutralizing carbonate minerals. Some of the vanadium-bearing deposit types, particularly some SSV and black-shale deposits, contain appreciable amounts of carbonate minerals, which lowers the acid-generation potential.Vanadium is a micronutrient with a postulated requirement for humans of less than 10 micrograms per day, which can be met through dietary intake. Primary and secondary drinking water regulations for vanadium are not currently in place in the United States. Vanadium toxicity is thought to result from an intake of more than 10 to 20 milligrams

Estudio de la extracción de Ni, Co y Fe en lateritas por medio de lixiviación ácida en columnas

Directory of Open Access Journals (Sweden)

di Yorio, C.

2006-02-01

Full Text Available In the following work the possibility of the nickel recovery by hydrometallurgy extraction for nickeliferous laterites is studied. The work looks for to study the technical viability of the extraction of nickel and cobalt by means of the application of heap leaching. The ore is chemically and physically characterized with the purpose of analyzes its composition and mineral phase, by means of x-rays diffraction, quantitative chemical analysis and elementary chemical analysis by electronic microscopy. Once the ore is characterized, it is mixed with sulfuric acid to relations 0.05; 0.1 and 0.2 g acid/g to agglomerated pellets and paste, with the aim to improve the percolation in column, due to the argillaceous nature of the ore leaching rate ranged from 0.305 to 1.06 x10 l/h*m2 and in the agglomerate condition of the percolation l/h*m2 improves at interval 3.05 to 6.11 x10 l/h*m2. Additionally the agglomerate ones are roasted with the purpose of consolidating them and chemically preparing the ore so that it is susceptible to the leaching, by means of oxides sulphation of the ore to high temperatures. This ore preparation is subject under diverse leaching tests like: dynamic tests and columns tests. The dynamic tests were made for different relations solid-liquid from 0.05 from 0.5 x103 g/l, different concentrations of the leaching solution and different reaction times from 24 to 168 h. As far as the columns tests showed, the variables studied were acid/ore mixture ratio, continuity of the leaching irrigation, reusability of the liquor of leaching and roasted temperature which was done from 673, 873 and 1023 K. With these tests times selectivity for nickel and cobalt versus iron were found, obtaining recovery 17 more times nickel than iron and up to 26 more times cobalt than iron and with an high process speed, where most of the recovery is made in the first 24 h.

En el siguiente trabajo se plantea la posibilidad de la extracción de n

Microfacies, Sedimentary Environment and Relative Sea Level Changes of the Ruteh Formation, Sangsar and Makaroud Sections, Central Alborz

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Leili Bastami

2016-12-01

Full Text Available Introduction According to different paleontological and paleomagnetic studies, Iran was part of the Gondwana during the Permian. The Permian lithostratigraphic units in the Alborz-Azerbaijan are introduced as Doroud, Ruteh and Nesen Formations. The Ruteh Formation, the second depositional cycle of the Permian in the Alborz Basin, have been studied at two stratigraphic sections in the Central Alborz. The Sangsar section located on the south flank of the Central Alborz, 1 km northwest of Mahdishahr city and the Makaroud section located on the north flank of the Central Alborz, about 37 km south of Chalous city. The thickness of the Ruteh Formation at the Sangsar section is 106 m and at the Makaroud section is 222 m. At the Sangsar section the Ruteh Formation is underlain by the Doroud Formation with gradual contact and is overlain by a lateritic horizon. At the Makaroud section the Ruteh Formation disconformably overlies the Doroud Formation and the upper boundary is faulted and the Chalous Formation overlies the Ruteh Formation at this section. The aim of this paper is to analysis microfacies, interpret depositional environments and delineate relative sea level changes of the Ruteh Formation. Other researchers studied the Ruteh Formation at different sections in the Alborz Basin believe that the carbonate sediments of this formation have been deposited in a homoclinal carbonate ramp and consist of two-three 3rd order depositional sequences. But no sedimentological studies have been done at the selected sections in this study.   Material & Methods Two stratigraphic sections of the Ruteh Formation have been selected, measuted and sampled. One hundred sixty three samples (fifty seven samples from Sangsar and one hundred six samples from Makaroud section  were collected and thin sections were prepared from all samples. Afew samples were collected from lower and upper formations. Thin sections were stained with potassium ferricyanide and alizarin

The use of soil quality indicators to assess soil functionality in restored semi-arid ecosystems

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Muñoz-Rojas, Miriam; Erickson, Todd E.; Dixon, Kingsley W.; Merritt, David J.

2016-04-01

Keywords: Pilbara, 1-day CO2 test, microbial activity, mine restoration, soil health, ecosystem services. Introduction Semi-arid and arid environments are highly vulnerable to land degradation and their restoration has commonly showed low rates of success (James et al., 2013). A systematic knowledge of soil functionality is critical to successful restoration of degraded ecosystems since approximately 80% of ecosystem services can be connected to soil functions. The assessment of soil functionality generally involves the evaluation of soil properties and processes as they relate to the ability of soil to function effectively as a component of a healthy ecosystem (Costantini et al., 2015) Using soil quality indicators may be a valuable approach to assess functionality of topsoil and novel substrates used in restoration (Muñoz-Rojas et al., 2014; 2015). A key soil chemical indicator is soil organic C, that has been widely used as an attribute of soil quality because of the many functions that it provides and supports (Willaarts et al., 2015). However, microbial indicators can be more sensitive to disturbances and could be a valuable addition in soil assessment studies in restoration programs. Here, we propose a set of soil quality indicators to assess the soil status in restored soils (topsoil and waste material) of semi-arid environments. The study was conducted during March 2015 in the Pilbara biogeographical region (northwestern Australia) at an iron ore mine site rehabilitated in 2011. Methods Soil samples were collected from two sub-areas with different soil materials used as growth media: topsoil retrieved from nearby stockpiles and a lateritic waste material utilised for its erosive stability and physical competence. An undisturbed natural shrub-grassland ecosystem dominated by Triodia spp. and Acacia spp. representative of the restored area was selected as the analogue reference site. Soil physicochemical analysis were undertaken according to standard methods

Groundwater contamination in the basement-complex area of Ile-Ife, southwestern Nigeria: A case study using the electrical-resistivity geophysical method

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Adepelumi, A. A.; Ako, B. D.; Ajayi, T. R.

2001-11-01

Hydrogeoenvironmental studies were carried out at the sewage-disposal site of Obafemi Awolowo University campus, Ile-Ife, Nigeria. The objective of the survey was to determine the reliability of the electrical-resistivity method in mapping pollution plumes in a bedrock environment. Fifty stations were occupied with the ABEM SAS 300C Terrameter using the Wenner array. The electrical-resistivity data were interpreted by a computer-iteration technique. Water samples were collected at a depth of 5.0 m in 20 test pits and analyzed for quality. The concentrations of Cr, Cd, Pb, Zn, and Cu are moderately above the World Health Organization recommended guidelines. Plumes of contaminated water issuing from the sewage ponds were delineated. The geoelectric sections reveal four subsurface layers, with increasing depth, lateritic clay, clayey sand/sand, and weathered/fractured bedrock, and fresh bedrock. The deepest layers, 3 and 4, constitute the main aquifer, which has a thickness of 3.1-67.1 m. The distribution of the elements in the sewage effluent confirms a hydrological communication between the disposal ponds and groundwater. The groundwater is contaminated, as shown by sampling and the geophysical results. Thus, the results demonstrate the reliability of the direct-current electrical-resistivity geophysical method in sensing and mapping pollution plumes in a crystalline bedrock environment. Résumé. Des études géo-environnementales ont été réalisées sur le site d'épandages du campus universitaire d'Obafemi Awolowo, à Ile-Ife (Nigeria). L'objectif de ce travail était de déterminer la fiabilité de la méthode des résistivités électriques pour cartographier les panaches de pollution dans un environnement de socle. Cinquante stations ont été soumises à mesures au moyen d'un ABEM SAS 300C Terrameter en utilisant le dispositif de Wenner. Les données de résistivité électrique ont été interprétées au moyen d'une technique de calcul itérative. Des �

Critical Zone Exploration in the Tropics: Clues from small experimental watersheds in South Cameroon and South India

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Braun, J.-J.; Riotte, J.; Audry, S.; Boeglin, J. L.; Descloitres, M.; Deschamps, P.; Maréchal, J. C.; Viers, J.; Ndam, J.-R.; Sekhar, M.

2009-04-01

characterized by a deep mature lateritic mantle and mean annual rainfall of 1600 mm. The second watershed, under investigation since 2003, is located at Mule Hole, South India. It belongs to the sub-humid zone of the climatic gradient of the Kabini River basin in the rain shadow of the Western Ghâts. It is characterized by an immature thick regolith and mean annual rainfall of 1100 mm. In both watersheds, the water balance was calculated from on time-series of hydrological and climatic data and then modelled for lean/normal/high rainfall years. The contemporary chemical weathering rates were established by coupling the water balance with geochemical time-series in groundwater, stream water and rainfall. The degree of weathering and the thickness of the regolith were achieved by combining investigations of geophysics (electrical resistivity logging and tomography), mineralogy, and bulk chemical analyses. This allowed us to assess the long-term chemical weathering mass balance at the watershed scale. In the Nsimi watershed, the contemporary chemical weathering rate, even though low (2.8 mm/kyr), predominates over the mechanical weathering rate (1.9 mm/kyr). Compared to the Rio Icacos watershed, the most studied tropical site, the chemical weathering fluxes of silica and sodium in the stream are 16 and 40 times lower, respectively. This is not only related to the protective role of the regolith, thick in both cases, but also to differences in the hydrological functioning. The carbon transfer occurs primarily in an organic form and essentially as colloids produced by the slow biodegradation of the swamp organic matter. These organic colloids contribute significantly to the mobilization and transfer of Fe, Al, Zr, Ti and Th in the uppermost first meter of the swamp regolith. In the Mule Hole watershed, the contemporary mechanical weathering rate (25 mm/kyr), predominates over the chemical weathering rate estimated for both stream (0.3 mm/kyr) and groundwater (3.0 mm/kyr). This

Surficial geology and geomorphology of Potter County, Pennsylvania

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Denny, C.S.

1956-01-01

summits are composed approximately of 25 species of trees. The northern hardwood region includes most of the county, with an oak-forest region near the borders, principally along its southern margin. Potter County is underlain by sandstone, siltstone, shale, conglomerate, and minor amounts of coal and calcareous rock that range in age from Late Devonian to Pennsylvanian. These rocks form broad open folds that strike northeast. South of the border of the Wisconsin drift, and possibly at two localities inside the drift border, are scattered remnants of ancient soils (here called paleosol), that were formed in preWisconsin time-probably during the Sangamon interglacial stage. This paleosol ranges in texture from clay loam to silt loam, ranges in color from yellowish red to red, includes a few percent to more than 25 percent of rock fragments, and apparently contains a small percentage of gibbsite and varying amounts of kaolinite. Known thicknesses range from 1 to 33 feet. Paleosol was developed on diverse kinds of parent material, such as till, stratified drift, colluvium, and residuum, at altitudes ranging from a few hundred to 2,400 feet. The climatic conditions under which the paleosol formed are uncertain; however, these ancient soils may record an episode of subtropical climatic conditions during which lateritic soils were formed. Perhaps these soils are analogous to the Red-Yellow Podzolic soils of southeastern United States. Except for one possible remnant, no pre-Wisconsin drift has been recognized in Potter County. The Wisconsin glacial deposits of Potter County belong to either the Iowan or Tazewell substages and are dominantly till with minor amounts of glaciofluvial deposits. Erratics of igneous or metamorphic rock comprise less than 0.1 percent of the total number of rock fragments. The till is slightly weathered to depths ranging from 3 to about 12 feet. The drift border is indefinite and has been drawn at the southern limit of erratics or well-rounded or

Geology and ground-water resources of the island of Oahu, Hawaii

Science.gov (United States)

Stearns, Harold T.; Vaksvik, Knute N.

1935-01-01

master streams are characterized by deep amphitheater-headed valleys. After this erosion cycle the island was submerged more than 1,200 feet, and these great valleys were drowned and alluviated. Besides this submergence, several strand lines, preserved up to 100 feet above present sea level occur, which may be due to world-wide changes in sea level in response to the withdrawal and restoration of water concurrent with the advances and recessions of the polar ice caps and to accompanying changes in the ocean floor. During this time of shifting ocean levels spasmodic eruptions occurred on the southeast end of the Koolau Range, producing numerous lava flows and tuff cones, most of which are nephelite basalt. The last of these eruptions occurred in Recent time. A description of the climate, rates of run-off, and results of experiments to determine evaporation and transpiration in the areas of high rainfall are given. It was found that the consumptive use decreases materially and becomes a very small percentage of the rainfall in the areas of high precipitation. The lava rocks of the island are very permeable and, because of a rainfall reaching a maximum of 300 inches a year, carry large amounts of ground water, confined and unconfined, basal and perched. The basal ground water floats on salt water because of its lower specific gravity. Consequently for each foot the water table stands above sea level, salt water lies about 42 feet below sea level, in accordance with the sea along the coast as basal ground water. In most places the lava rocks along the shore are overlain by an impermeable or nearly impermeable caprock consisting of submerged lateritic soils and marine noncalcareous sediments. These deposits retard the escape of basal ground water into the sea and give rise to artesian water, but unlike most other artesian systems, this one has no lower restraining formation. The artesian water is the principal source of domestic, municipal, and irrigation supplies. The

Projects of Earth Sciences Supported by National Natural Science Foundation of China

Institute of Scientific and Technical Information of China (English)

无

2001-01-01

-shou 40001019\tGenetic Algorithm Approach to Automation and Intelligence of Map Name Placement\tFAN Hong 40001020\tEnvironmental Magnetic Study of Sedimentary Iron Cycling during Early Diagnoses\tZHANG Wei-guo 40001021\tModeling of Nitrogen and Water Input-yield-leaching Loss Response and the Nitrogen Transformation and Transportation\tZHANG Guo-liang 40001022\tThe Study on the Regional Differentiation of Lake Environment Response to Southwest Monsoon Climate\tPENG Jin-lan 40001023\tCritical Loads of Acid Deposition for Ecosystems and Their Exceedance in Regions Suffered from Acid Deposition in China\tTAO Fu-lu 40031010\tRegional Environmental Processes of Typical Trace Organic Pollutants\tTAO Shu 40061001\tAnalysis on the Structure of Karst Watershed and the Characteristics of Low Flow\tLIANG Hong 40061002\tThe Development Feature, Dynamic Mechanism and Coordination Research of Urban Concentric Region in West of Yunnan Province and Its Demonstration to Undeveloped, Minority Concentric Region of China\tWU Qi-yan 40061003\tThe REE Background Value and Its Influence on Soil Fertility in Laterite in the Hainan Island\tBI Hua 40061004\tStudies on the Mechanism of Soil Fertility Degradation and Techniques of Fertilization Under Arable Soils Condition in the "One-Jiang River and Two-He River" Region in Tibet\tCAI Xiao-bu 40061005\tA Study on Major Factors, Countermeasures and Mechanism of Bahia Grass Later-stage Degeneration at Rare-earth Tailings\tDONG Wen-da 40061006\tStudy on Soil Erosion and Land Use Security Pattern in Jinsha River Basin of Yunnan\tYANG Zi-sheng 40061007\tA Study on Environment Dynamic Chart of Southern Mountain Area of Ningxia under Eco-Restoration and Wide Development in West China\tSUI Yu-zhu 40061008\tThe Site Study of Environment Carrying Capacity for Tourism in Bita Reserve, Northwestern Yunnan\tYANG Gui-hua 40071001\tResearch on Sedimentary Processes and Varve Records of Lake Environment for Meromictic Lake on the Qinghai-Xizang (Tibet) Plateau\tLI Shi