Incoherent SSI Analysis of Reactor Building using 2007 Hard-Rock Coherency Model

International Nuclear Information System (INIS)

Kang, Joo-Hyung; Lee, Sang-Hoon

2008-01-01

Many strong earthquake recordings show the response motions at building foundations to be less intense than the corresponding free-field motions. To account for these phenomena, the concept of spatial variation, or wave incoherence was introduced. Several approaches for its application to practical analysis and design as part of soil-structure interaction (SSI) effect have been developed. However, conventional wave incoherency models didn't reflect the characteristics of earthquake data from hard-rock site, and their application to the practical nuclear structures on the hard-rock sites was not justified sufficiently. This paper is focused on the response impact of hard-rock coherency model proposed in 2007 on the incoherent SSI analysis results of nuclear power plant (NPP) structure. A typical reactor building of pressurized water reactor (PWR) type NPP is modeled classified into surface and embedded foundations. The model is also assumed to be located on medium-hard rock and hard-rock sites. The SSI analysis results are obtained and compared in case of coherent and incoherent input motions. The structural responses considering rocking and torsion effects are also investigated

Modelling of nuclear explosions in hard rock sites

International Nuclear Information System (INIS)

Brunish, W.M.; App, F.N.

1993-01-01

This study represents part of a larger effort to systematically model the effects of differing source region properties on ground motion from underground nuclear explosions at the Nevada Test Site. In previous work by the authors the primary emphasis was on alluvium and both saturated and unsaturated tuff. We have attempted to model events on Pahute Mesa, where either the working point medium, or some of the layers above the working point, or both, are hard rock. The complex layering at these sites, however, has prevented us from drawing unambiguous conclusions about modelling hard rock

Aespoe Hard Rock Laboratory Annual report 2003

Energy Technology Data Exchange (ETDEWEB)

NONE

2004-09-01

The Aespoe Hard Rock Laboratory (HRL) constitutes an important part of SKB's work to design and construct a deep geological repository for spent nuclear fuel and to develop and test methods for characterisation of a suitable site for a deep repository. One of the fundamental reasons behind SKB's decision to construct an underground laboratory was to create an opportunity for research, development and demonstration in a realistic and undisturbed rock environment down to repository depth. Aespoe HRL has been in operation since 1995 and the associated research, development, and demonstration tasks, have so far attracted considerable interest. A summary of work performed at Aespoe HRL during 2003 is given below. Seven organisations from six countries participated in the co-operation at Aespoe HRL during 2003 in addition to SKB. Most of the organisations are interested in groundwater flow, radionuclide transport and rock characterisation. Several of the organisations are participating in the experimental work as well as in the Aespoe Task Force on Modelling of Groundwater Flow and Transport of Solutes. SKB is through Repository Technology co-ordinating three EC contracts and takes part in several EC projects of which the representation in five projects is channelled through Repository Technology. SKB takes also part in work within the IAEA framework.

Aespoe Hard Rock Laboratory Annual report 2003

International Nuclear Information System (INIS)

2004-09-01

The Aespoe Hard Rock Laboratory (HRL) constitutes an important part of SKB's work to design and construct a deep geological repository for spent nuclear fuel and to develop and test methods for characterisation of a suitable site for a deep repository. One of the fundamental reasons behind SKB's decision to construct an underground laboratory was to create an opportunity for research, development and demonstration in a realistic and undisturbed rock environment down to repository depth. Aespoe HRL has been in operation since 1995 and the associated research, development, and demonstration tasks, have so far attracted considerable interest. A summary of work performed at Aespoe HRL during 2003 is given below. Seven organisations from six countries participated in the co-operation at Aespoe HRL during 2003 in addition to SKB. Most of the organisations are interested in groundwater flow, radionuclide transport and rock characterisation. Several of the organisations are participating in the experimental work as well as in the Aespoe Task Force on Modelling of Groundwater Flow and Transport of Solutes. SKB is through Repository Technology co-ordinating three EC contracts and takes part in several EC projects of which the representation in five projects is channelled through Repository Technology. SKB takes also part in work within the IAEA framework

MANAGEMENT AND TREATMENT OF WATER FROM HARD-ROCK MINES {ENGINEERING ISSUE}

Science.gov (United States)

This Engineering Issue document on treatment of mining waters is a practical guide to understanding and selecting technologies for the environmental management of waste materials and effluents at hard-rock mines. For the purposes of this discussion, hard-rock mining primarily ref...

Aespoe Hard Rock Laboratory. Annual Report 2006

Energy Technology Data Exchange (ETDEWEB)

NONE

2006-06-15

The Aespoe Hard Rock Laboratory (HRL) is an important part of SKB's work with the design and construction of a deep geological repository for the final disposal of spent nuclear fuel. Aespoe HRL is located in the Simpevarp area in the municipality of Oskarshamn. One of the fundamental reasons behind SKB's decision to construct an underground laboratory was to create opportunities for research, development and demonstration in a realistic and undisturbed rock environment down to repository depth. The underground part of the laboratory consists of a tunnel from the Simpevarp peninsula to the southern part of Aespoe where the tunnel continues in a spiral down to a depth of 460 m. Aespoe HRL has been in operation since 1995 and considerable international interest has been shown in its research, as well as in the development and demonstration tasks. The work performed at Aespoe HRL during 2006 is in this report described in six chapters: Geo-science - experiments, analysis and modelling to increase the knowledge of the surrounding rock; Natural barriers - experiments, analysis and modelling to increase the knowledge of the repository barriers under natural conditions; Engineered barriers - demonstration of technology for and function of important engineered parts of the repository barrier system; Aespoe facility - operation, maintenance, data management, monitoring, public relations etc; Environmental research; and finally, International co-operation.

Aespoe Hard Rock Laboratory. Annual Report 2006

International Nuclear Information System (INIS)

2006-06-01

The Aespoe Hard Rock Laboratory (HRL) is an important part of SKB's work with the design and construction of a deep geological repository for the final disposal of spent nuclear fuel. Aespoe HRL is located in the Simpevarp area in the municipality of Oskarshamn. One of the fundamental reasons behind SKB's decision to construct an underground laboratory was to create opportunities for research, development and demonstration in a realistic and undisturbed rock environment down to repository depth. The underground part of the laboratory consists of a tunnel from the Simpevarp peninsula to the southern part of Aespoe where the tunnel continues in a spiral down to a depth of 460 m. Aespoe HRL has been in operation since 1995 and considerable international interest has been shown in its research, as well as in the development and demonstration tasks. The work performed at Aespoe HRL during 2006 is in this report described in six chapters: Geo-science - experiments, analysis and modelling to increase the knowledge of the surrounding rock; Natural barriers - experiments, analysis and modelling to increase the knowledge of the repository barriers under natural conditions; Engineered barriers - demonstration of technology for and function of important engineered parts of the repository barrier system; Aespoe facility - operation, maintenance, data management, monitoring, public relations etc; Environmental research; and finally, International co-operation

In Situ Observation of Hard Surrounding Rock Displacement at 2400-m-Deep Tunnels

Science.gov (United States)

Feng, Xia-Ting; Yao, Zhi-Bin; Li, Shao-Jun; Wu, Shi-Yong; Yang, Cheng-Xiang; Guo, Hao-Sen; Zhong, Shan

2018-03-01

This paper presents the results of in situ investigation of the internal displacement of hard surrounding rock masses within deep tunnels at China's Jinping Underground Laboratory Phase II. The displacement evolution of the surrounding rock during the entire excavation processes was monitored continuously using pre-installed continuous-recording multi-point extensometers. The evolution of excavation-damaged zones and fractures in rock masses were also observed using acoustic velocity testing and digital borehole cameras, respectively. The results show four kinds of displacement behaviours of the hard surrounding rock masses during the excavation process. The displacement in the inner region of the surrounding rock was found to be greater than that of the rock masses near the tunnel's side walls in some excavation stages. This leads to a multi-modal distribution characteristic of internal displacement for hard surrounding rock masses within deep tunnels. A further analysis of the evolution information on the damages and fractures inside the surrounding rock masses reveals the effects of excavation disturbances and local geological conditions. This recognition can be used as the reference for excavation and supporting design and stability evaluations of hard-rock tunnels under high-stress conditions.

Aespoe hard rock laboratory. Annual report 1992

International Nuclear Information System (INIS)

1993-04-01

The Aespoe hard rock laboratory is being constructed in preparation for the deep geological repository of spent fuel in Sweden. This Annual report 1992 for the Aespoe hard rock laboratory contains an overview of the work conducted. Present work is focused on verification of pre-investigation methods and development of the detailed investigation methodology. Construction of the facility and investigation of the bedrock are being carried out in parallel. December 1992 1925 m of the tunnel has been excavated to a depth of 255 m below surface. An important and integrated part of the work is further refinement of conceptual and numerical models for groundwater flow and radionuclide migration. This work is carried out in cooperation with seven organizations from six countries that participate in the project. (25 refs.)

Experimental Study of Bilinear Initiating System Based on Hard Rock Pile Blasting

Directory of Open Access Journals (Sweden)

Yusong Miao

2017-01-01

Full Text Available It is difficult to use industrial explosives to excavate hard rock and achieve suitable blasting effect due to the low energy utilization rate resulting in large rocks and short blasting footage. Thus, improving the utilization ratio of the explosive energy is important. In this study, a novel bilinear initiation system based on hard rock blasting was proposed to improve the blasting effects. Furthermore, on the basis of the detonation wave collision theory, frontal collision, oblique reflection, and Mach reflection during detonation wave propagation were studied. The results show that the maximum detonation pressure at the Mach reflection point where the incident angle is 46.9° is three times larger than the value of the explosive complete detonation. Then, in order to analyze the crack propagation in different initiation forms, a rock fracture test slot was designed, and the results show that bilinear initiating system can change the energy distribution of explosives. Finally, field experiment was implemented at the hard rock pile blasting engineering, and experimental results show that the present system possesses high explosive energy utilization ratio and low rock fragments size. The results of this study can be used to improve the efficiency in hard rock blasting.

Dynamic design method for deep hard rock tunnels and its application

Directory of Open Access Journals (Sweden)

Xia-Ting Feng

2016-08-01

Full Text Available Numerous deep underground projects have been designed and constructed in China, which are beyond the current specifications in terms of scale and construction difficulty. The severe failure problems induced by high in situ stress, such as rockburst, spalling, damage of deep surrounding rocks, and time-dependent damage, were observed during construction of these projects. To address these problems, the dynamic design method for deep hard rock tunnels is proposed based on the disintegration process of surrounding rocks using associated dynamic control theories and technologies. Seven steps are basically employed: (i determination of design objective, (ii characteristics of site, rock mass and project, and identification of constraint conditions, (iii selection or development of global design strategy, (iv determination of modeling method and software, (v preliminary design, (vi comprehensive integrated method and dynamic feedback analysis, and (vii final design. This dynamic method was applied to the construction of the headrace tunnels at Jinping II hydropower station. The key technical issues encountered during the construction of deep hard rock tunnels, such as in situ stress distribution along the tunnels, mechanical properties and constitutive model of deep hard rocks, determination of mechanical parameters of surrounding rocks, stability evaluation of surrounding rocks, and optimization design of rock support and lining, have been adequately addressed. The proposed method and its application can provide guidance for deep underground projects characterized with similar geological conditions.

Experiments at the Aespoe Hard Rock Laboratory

International Nuclear Information System (INIS)

2004-12-01

A dress rehearsal is being held in preparation for the construction of a deep repository for spent nuclear fuel at SKB's underground Hard Rock Laboratory (HRL) on Aespoe, outside Oskarshamn. Here we can test different technical solutions on a full scale and in a realistic environment. The Aespoe HRL is also used for field research. We are conducting a number of experiments here in collaboration with Swedish and international experts. In the Zedex experiment we have compared how the rock is affected around a drill-and-blast tunnel versus a bored tunnel. In a new experiment we will investigate how much the rock can take. A narrow pillar between two boreholes will be loaded to the point that the rock's ultimate strength is exceeded (Aespoe Pillar Stability Experiment). In the Demo Test we are demonstrating emplacement of the copper canisters and the surrounding bentonite in the deposition holes. In the Prototype Repository we study what long-term changes occur in the barriers under the conditions prevailing in a deep repository. Horizontal deposition: Is it possible to deposit the canisters horizontally without compromising safety? Backfill and Plug Test: The tunnels in the future deep repository for spent nuclear fuel will be filled with clay and crushed rock and then plugged. Canister Retrieval Test: If the deep repository should not perform satisfactorily for some reason, we want to be able to retrieve the spent fuel. The Lot test is intended to show how the bentonite behaves in an environment similar to that in the future deep repository. The purpose of the TBT test is to determine how the bentonite clay in the buffer is affected by high temperatures. Two-phase flow means that liberated gas in the groundwater flows separately in the fractures in the rock. This reduces the capacity of the rock to conduct water. Lasgit: By pressurizing a canister with helium, we can measure how the gas moves through the surrounding buffer. Colloid Project: Can very small particles

Appraisal of hard rock for potential underground repositories of radioactive wastes. LBL-7004

International Nuclear Information System (INIS)

Cook, N.G.W.

1978-01-01

Underground burial of radioactive wastes in hard rock may be an effective and safe means of isolating them from the environment and from man. The mechanical safety and stability of such an underground repository depends largely on the virgin state of stress in the rock, groundwater pressures, the strengths of the rocks, heating by the decay of the radioactive wastes, and the layout of the excavations and the disposition of waste cannisters within them. A large body of pertinent data exists in the literature, and each of these factors has been analyzed in the light of this information. The results indicate that there are no fundamental geological nor mechanical reasons why repositories capable of storing radioactive wastes should not be excavated at suitable sites in hard rock. However, specific tests to determine the mechanical and thermal properties of the rocks at a site would be needed to provide the data for the engineering design of a repository. Also, little experience exists of the effects on underground excavations of thermal loads, so that this aspect requires theoretical study and experimental validation. The depths of these potential repositories would lie in the range from 0.5 km to 2.0 km below surface, depending upon the strength of the rock. Virgin states of stress have been measured at such depths which would retard the ingress of groundwater and obviate the incidence of faulting. A typical repository comprising three horizons each with a total area of 5 km 2 would have the capacity to store wastes with thermal output of 240 MW

Geotechnical issues and guidelines for storage of compressed air in excavated hard rock caverns

Energy Technology Data Exchange (ETDEWEB)

Allen, R.D.; Doherty, T.J.; Fossum, A.F.

1982-04-01

The results of a literature survey on the stability of excavated hard rock caverns are presented. The objective of the study was to develop geotechnical criteria for the design of compressed air energy storage (CAES) caverns in hard rock formations. These criteria involve geologic, hydrological, geochemical, geothermal, and in situ stress state characteristics of generic rock masses. Their relevance to CAES caverns, and the identification of required research areas, are identified throughout the text. This literature survey and analysis strongly suggests that the chief geotechnical issues for the development and operation of CAES caverns in hard rock are impermeability for containment, stability for sound openings, and hydrostatic balance.

Research on definition of hard rock shear wave velocity of site for nuclear power plant

International Nuclear Information System (INIS)

Ding Zhenkun; Xia Zufeng

2013-01-01

Background: The definition of hard rock shear wave velocity is one of the most critical issues in the work of site selection. Purpose: To make a definition of hard rock site on which the model can be assumed as fixed-base condition, a series of research had been done. Several possible hard rock site soil models were developed. Methods: Shear wave velocity of hard rock had been assumed from 1100 m/s to 3200 m/s. For each case, free field analysis and soil structure analysis had been performed. And responses in soil and key nodes of structure were compared. Results: In free field analysis, responses of models that shear wave velocity below 2400 m/s decreased a lot. In SSI analysis, structure responses didn't change much when shear wave velocity was above 2400 m/s. Conclusions: 2400 m/s was the lowest shear wave velocity for hard rock site for fixed-base assumption. (authors)

Evaluation of Rock Bolt Support for Polish Hard Rock Mines

Science.gov (United States)

Skrzypkowski, Krzysztof

2018-03-01

The article presents different types of rock bolt support used in Polish ore mining. Individual point resin and expansion rock bolt support were characterized. The roof classes for zinc and lead and copper ore mines were presented. Furthermore, in the article laboratory tests of point resin rock bolt support in a geometric scale of 1:1 with minimal fixing length of 0.6 m were made. Static testing of point resin rock bolt support were carried out on a laboratory test facility of Department of Underground Mining which simulate mine conditions for Polish ore and hard coal mining. Laboratory tests of point resin bolts were carried out, especially for the ZGH Bolesław, zinc and lead "Olkusz - Pomorzany" mine. The primary aim of the research was to check whether at the anchoring point length of 0.6 m by means of one and a half resin cartridge, the type bolt "Olkusz - 20A" is able to overcome the load.The second purpose of the study was to obtain load - displacement characteristic with determination of the elastic and plastic range of the bolt. For the best simulation of mine conditions the station steel cylinders with an external diameter of 0.1 m and a length of 0.6 m with a core of rock from the roof of the underground excavations were used.

Experimental Investigation of the Influence of Confining Stress on Hard Rock Fragmentation Using a Conical Pick

Science.gov (United States)

Li, Xibing; Wang, Shaofeng; Wang, Shanyong

2018-01-01

High geostress is a prominent condition in deep excavations and affects the cuttability of deep hard rock. This study aims to determine the influence of confining stress on hard rock fragmentation as applied by a conical pick. Using a true triaxial test apparatus, static and coupled static and dynamic loadings from pick forces were applied to end faces of cubic rock specimens to break them under biaxial, uniaxial and stress-free confining stress conditions. The cuttability indices (peak pick force, insertion depth and disturbance duration), failure patterns and fragment sizes were measured and compared to estimate the effects of confining stress. The results show that the rock cuttabilities decreased in order from rock breakages under stress-free conditions to uniaxial confining stress and then to biaxial confining stress. Under biaxial confining stress, only flake-shaped fragments were stripped from the rock surfaces under the requirements of large pick forces or disturbance durations. As the level of uniaxial confining stress increased, the peak pick force and the insertion depth initially increased and then decreased, and the failure patterns varied from splitting to partial splitting and then to rock bursts with decreasing average fragment sizes. Rock bursts will occur under elastic compression via ultra-high uniaxial confining stresses. There are two critical uniaxial confining stress levels, namely stress values at which peak pick forces begin to decrease and improve rock cuttability, and those at which rock bursts initially occur and cutting safety decreases. In particular, hard rock is easiest to split safely and efficiently under stress-free conditions. Moreover, coupled static preloading and dynamic disturbance can increase the efficiency of rock fragmentation with increasing preloading levels and disturbance amplitudes. The concluding remarks confirm hard rock cuttability using conical pick, which can improve the applicability of mechanical excavation in

Evaluation of dynamic characteristics of hard rock based on numerical simulations of in situ rock tests

International Nuclear Information System (INIS)

Yamagami, Yuya; Ikusada, Koji; Jiang, Yujing

2009-01-01

In situ rock tests of hard rock of conglomerate in which discontinuities in high angle are dominant were conducted. In this study, in order to confirm the validity of the test results and the test condition, and in order to elucidate the deformation behaviour and the mechanism of shear strength of the rock mass, the numerical simulations of the in situ rock tests by using distinct element method were performed. As a result, it was clarified that the behaviour of the rock mass strongly depends on both geometrical distribution of discontinuities and those mechanical properties. It is thought that a series of evaluation processes showed in this study contribute to improve the reliability of the dynamic characteristic evaluation of the rock mass. (author)

Aespoe Hard Rock Laboratory Annual Report 1999

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-08-01

The Aespoe Hard Rock Laboratory has been constructed as part of the preparations for the deep geological repository for spent nuclear fuel in Sweden. The Tracer Retention Understanding Experiments are made to gain a better understanding of radionuclide retention in the rock and create confidence in the radionuclide transport models that are intended to be used in the licensing of a deep repository for spent fuel. The TRUE -1 experiment including tests with sorbing radioactive tracers in a single fracture over a distance of about 5 m has been completed. Diffusion and sorption in the rock matrix is the dominant retention mechanism over the time scales of the experiments. The main objective of the TRUE Block Scale Experiment is to increase understanding and our ability to predict tracer transport in a fracture network over spatial scales of 10 to 50 m. In total six boreholes have been drilled into the experimental volume located at the 450 m level. The Long-Term Diffusion Experiment is intended as a complement to the dynamic in-situ experiments and the laboratory experiments performed in the TRUE Programme. Diffusion from a fracture into the rock matrix will be studied in situ. The REX project focuses on the reduction of oxygen in a repository after closure due to reactions with rock minerals and microbial activity. Results show that oxygen is consumed within a few days both for the field and laboratory experiments. A new site for the CHEMLAB experiments was selected and prepared during 1999. All future experiment will be conducted in the J niche at 450 m depth. The Prototype Repository Test is focused on testing and demonstrating repository system function. A full-scale prototype including six deposition holes with canisters with electric heaters surrounded by highly compacted bentonite will be built and instrumented. Characterisation of the rock mass in the area of the Prototype repository is completed and the six deposition holes have been drilled. The Backfill and

Aespoe Hard Rock Laboratory Annual Report 1999

International Nuclear Information System (INIS)

2000-08-01

The Aespoe Hard Rock Laboratory has been constructed as part of the preparations for the deep geological repository for spent nuclear fuel in Sweden. The Tracer Retention Understanding Experiments are made to gain a better understanding of radionuclide retention in the rock and create confidence in the radionuclide transport models that are intended to be used in the licensing of a deep repository for spent fuel. The TRUE -1 experiment including tests with sorbing radioactive tracers in a single fracture over a distance of about 5 m has been completed. Diffusion and sorption in the rock matrix is the dominant retention mechanism over the time scales of the experiments. The main objective of the TRUE Block Scale Experiment is to increase understanding and our ability to predict tracer transport in a fracture network over spatial scales of 10 to 50 m. In total six boreholes have been drilled into the experimental volume located at the 450 m level. The Long-Term Diffusion Experiment is intended as a complement to the dynamic in-situ experiments and the laboratory experiments performed in the TRUE Programme. Diffusion from a fracture into the rock matrix will be studied in situ. The REX project focuses on the reduction of oxygen in a repository after closure due to reactions with rock minerals and microbial activity. Results show that oxygen is consumed within a few days both for the field and laboratory experiments. A new site for the CHEMLAB experiments was selected and prepared during 1999. All future experiment will be conducted in the J niche at 450 m depth. The Prototype Repository Test is focused on testing and demonstrating repository system function. A full-scale prototype including six deposition holes with canisters with electric heaters surrounded by highly compacted bentonite will be built and instrumented. Characterisation of the rock mass in the area of the Prototype repository is completed and the six deposition holes have been drilled. The Backfill and

Failure mechanism and coupled static-dynamic loading theory in deep hard rock mining: A review

Directory of Open Access Journals (Sweden)

Xibing Li

2017-08-01

Full Text Available Rock failure phenomena, such as rockburst, slabbing (or spalling and zonal disintegration, related to deep underground excavation of hard rocks are frequently reported and pose a great threat to deep mining. Currently, the explanation for these failure phenomena using existing dynamic or static rock mechanics theory is not straightforward. In this study, new theory and testing method for deep underground rock mass under coupled static-dynamic loading are introduced. Two types of coupled loading modes, i.e. “critical static stress + slight disturbance” and “elastic static stress + impact disturbance”, are proposed, and associated test devices are developed. Rockburst phenomena of hard rocks under coupled static-dynamic loading are successfully reproduced in the laboratory, and the rockburst mechanism and related criteria are demonstrated. The results of true triaxial unloading compression tests on granite and red sandstone indicate that the unloading can induce slabbing when the confining pressure exceeds a certain threshold, and the slabbing failure strength is lower than the shear failure strength according to the conventional Mohr-Column criterion. Numerical results indicate that the rock unloading failure response under different in situ stresses and unloading rates can be characterized by an equivalent strain energy density. In addition, we present a new microseismic source location method without premeasuring the sound wave velocity in rock mass, which can efficiently and accurately locate the rock failure in hard rock mines. Also, a new idea for deep hard rock mining using a non-explosive continuous mining method is briefly introduced.

Mining technology development for hard rock excavation

International Nuclear Information System (INIS)

Hustrulid, W.; Cudnick, R.; Trent, R.; Holmberg, R.

1980-01-01

A research facility has been established in the granitic gneiss of the CSM Experimental Mine at Idaho Springs, Colorado, for the purpose of evaluating/developing mining, geologic and geotechnical procedures appropriate for use in establishing nuclear waste repositories in hard rock. An experimental room has been excavated using careful blasting procedures. The extent and magnitude of blast damage is being evaluated. Structural geology is being mapped to assess continuity

Application of Confined Blasting in Water-Filled Deep Holes to Control Strong Rock Pressure in Hard Rock Mines

Directory of Open Access Journals (Sweden)

Jingxuan Yang

2017-11-01

Full Text Available In extra-thick coal seams, mining operations can lead to large-scale disturbances, complex overburden structures, and frequent and strong strata behavior in the stope, which are serious threats to mine safety. This study analyzed the overburden structure and strata behavior and proposed the technique of confined blasting in water-filled deep holes as a measure to prevent strong rock pressure. It found that there are two primary reasons for the high effectiveness of the proposed technique in presplitting hard coal and rock. First, the fracture water enables much more efficient transfer of dynamic load due to its incompressibility. Second, the subsequent expansion of water can further split the rock by compression. A mechanical model was used to reveal how the process of confined blasting in water-filled deep holes presplit roof. Moreover, practical implementation of this technique was found to improve the structure of hard, thick roof and prevent strong rock pressure, demonstrating its effectiveness in roof control.

Modelling of nuclear explosions in hard rock sites

International Nuclear Information System (INIS)

Brunish, W.M.; App, F.N.

1993-01-01

This study represents part of a larger effort to systematically model the effects of differing source region properties on ground motion from underground nuclear explosions at the Nevada Test Site. In previous work by the authors the primary emphasis was on alluvium and both saturated and unsaturated tuff. We have attempted to model events on Pahute Mesa, where either the working point medium, or some of the layers above the working point, or both, are hard rock. The complex layering at these sites, however, has prevented us from drawing unambiguous conclusions about modelling hard rock. In order to learn more about the response of hard rock to underground nuclear explosions, we have attempted to model the PILEDRIVER event. PILEDRIVER was fired on June 2, 1966 in the granite stock of Area 15 at the Nevada Test Site. The working point was at a depth of 462.7 m and the yield was determined to be 61 kt. Numerous surface, sub-surface and free-field measurements were made and analyzed by SRI. An attempt was made to determine the contribution of spall to the teleseismic signal, but proved unsuccessful because most of the data from below-shot-level gauges was lost. Nonetheless, there is quite a bit of good quality data from a variety of locations. We have been able to obtain relatively good agreement with the experimental PILEDRIVER waveforms. In order to do so, we had to model the granodiorite as being considerably weaker than ''good quality'' granite, and it had to undergo considerable weakening due to shock damage as well. In addition, the near-surface layers had to be modeled as being weak and compressible and as have a much lower sound speed than the material at depth. The is consistent with a fractured and jointed material at depth, and a weathered material near the surface

Water - rock interaction in different rock environments

International Nuclear Information System (INIS)

Lamminen, S.

1995-01-01

The study assesses the groundwater geochemistry and geological environment of 44 study sites for radioactive waste disposal. Initially, the study sites were divided by rock type into 5 groups: (1) acid - intermediate rocks, (2) mafic - ultramafic rocks, (3) gabbros, amphibolites and gneisses that contain calc-silicate (skarn) rocks, (4) carbonates and (5) sandstones. Separate assessments are made of acid - intermediate plutonic rocks and of a subgroup that comprises migmatites, granite and mica gneiss. These all belong to the group of acid - intermediate rocks. Within the mafic -ultramafic rock group, a subgroup that comprises mafic - ultramafic plutonic rocks, serpentinites, mafic - ultramafic volcanic rocks and volcanic - sedimentary schists is also evaluated separately. Bedrock groundwaters are classified by their concentration of total dissolved solids as fresh, brackish, saline, strongly saline and brine-class groundwaters. (75 refs., 24 figs., 3 tabs.)

IMPACT OF ROCK HARDNESS ON FRAGMENTATION BY HYDRAULIC HAMMER AND CRUSHING IN JAW CRUSHER

Directory of Open Access Journals (Sweden)

Trpimir Kujundžić

2008-12-01

Full Text Available The physical and mechanical characteristics of intact rocks depend on the way of their formation, sustained deformations and the process of wearing a specific rock has been exposed to. These characteristics have a rather high influence on the technological process of extraction and dressing of mineral raw materials. However, the mechanical characteristics of rocks due to use of explosives for their extraction in the open pit have a more significant impact. The rock blocks extracted by blasting which are larger than the opening of the primary crusher are usually fragmented by hydraulic hammer. The paper presents the results of the testing of impact of rock hardness on fragmentation of rocks by means of hydraulic hammer and during crushing in jaw crusher. The testing was carried out on the rock samples from five quarries. According to the obtained results the hardness has a considerably larger impact on the fragmentation energy by hydraulic hammer than on the crushing energy in jaw crusher.

Retractable Robotic Anchor for Hard Rock and Granular Soils, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — ProtoInnovations, LLC, is developing an innovative retractable robotic anchor that works in hard rock and granular soils permitting anchoring and subsequent...

Retractable Robotic Anchor for Hard Rock and Granular Soils, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — ProtoInnovations proposes to research, develop, and validate an innovative retractable robotic anchoring mechanism that works both in hard rock and granular soils...

Aespoe Hard Rock Laboratory. Annual report 1997

International Nuclear Information System (INIS)

1998-05-01

The Aespoe Hard Rock Laboratory has been constructed as part of the preparations for the deep geological repository for spent nuclear fuel in Sweden. The surface and borehole investigations and the research work performed in parallel with construction have provided a thorough test of methods for investigation and evaluation of bedrock conditions for construction of a deep repository. The Tracer Retention Understanding Experiments are made to gain a better understanding of radionuclide retention in the rock and create confidence in the radionuclide transport models that are intended to be used in the licensing of a deep repository for spent fuel. The experimental results of the first tracer test with sorbing radioactive tracers have been obtained. These tests have been subject to blind predictions by the Aespoe Task Force on groundwater flow and transports of solutes. The manufacturing of the CHEMLAB probe was completed during 1996, and the first experiments were started early in 1997. During 1997 three experiments on diffusion in bentonite using 57 Co, 114 Cs, 85 Sr, 99 Tc, and 131 I were conducted. The Prototype Repository Test is focused on testing and demonstrating repository system function. A full scale prototype including six deposition holes with canisters with electric heaters surrounded by highly compacted bentonite will be built and instrumented. The characterization of the rock mass in the area of the prototype repository is in progress. The objectives of the Demonstration of Repository Technology are to develop, test, and demonstrate methodology and equipment for encapsulation and deposition of spent nuclear fuel. The demonstration of handling and deposition will be made in a new drift. The Backfill and Plug Test includes tests of backfill materials and emplacement methods and a test of a full scale plug. The backfill and rock will be instrumented with about 230 transducers for measuring the thermo-hydro-mechanical processes. The Retrieval Test is

Heat-energy storage through semi-opened circulation into low-permeability hard-rock aquifers

Science.gov (United States)

Pettenati, Marie; Bour, Olivier; Ausseur, Jean-Yves; de Dreuzy, Jean-Raynald; de la Bernardie, Jérôme; Chatton, Eliot; Lesueur, Hervé; Bethencourt, Lorine; Mougin, Bruno; Aquilina, Luc; Koch, Florian; Dewandel, Benoit; Boisson, Alexandre; Mosser, Jean-François; Pauwels, Hélène

2016-04-01

In low-permeability environments, the solutions of heat storage are still limited to the capacities of geothermal borehole heat exchangers. The ANR Stock-en-Socle project explores the possibilities of periodic storage of sensitive heat1 in low-permeability environments that would offer much better performance than that of borehole heat exchangers, especially in terms of unit capacity. This project examines the storage possibilities of using semi-open water circulation in typically a Standing Column Well (SCW), using the strong heterogeneity of hard-rock aquifers in targeting the least favorable areas for water resources. To solve the main scientific issues, which include evaluating the minimum level of permeability required around a well as well as its evolution through time (increase and decrease) due to water-rock interaction processes, the study is based on an experimental program of fieldwork and modelling for studying the thermal, hydraulic and geochemical processes involved. This includes tracer and water-circulation tests by injecting hot water in different wells located in distinct hard-rock settings (i.e. granite and schist) in Brittany, Ploemeur (H+ observatory network) and Naizin. A numerical modelling approach allows studying the effects of permeability structures on the storage and heat-recovery capacities, whereas the modelling of reactive transfers will provide an understanding of how permeability evolves under the influence of dissolution and precipitation. Based on the obtained results, technical solutions will be studied for constructing a well of the SCW type in a low-permeability environment. This work will be completed by a technical and economic feasibility study leading to an investment and operations model. This study aims to describe the suitability of SCW storage for shallow geothermal energy. In order to reach these objectives, Stock-en-Socle is constructed around a public/private partnership between two public research organizations, G�

Geophysical Properties of Hard Rock for Investigation of Stress Fields in Deep Mines

Science.gov (United States)

Tibbo, M.; Young, R. P.; Schmitt, D. R.; Milkereit, B.

2014-12-01

A complication in geophysical monitoring of deep mines is the high-stress dependency of the physical properties of hard rocks. In-mine observations show anisotropic variability of the in situ P- and S-wave velocities and resistivity of the hard rocks that are likely related to stress field changes. As part of a comprehensive study in a deep, highly stressed mine located in Sudbury, Ontario, Canada, data from in situ monitoring of the seismicity, conductivity, stress, and stress dependent physical properties has been obtain. In-laboratory experiments are also being performed on borehole cores from the Sudbury mines. These experiments will measure the Norite borehole core's properties including elastic modulus, bulk modulus, P- and S-wave velocities, and density. Hydraulic fracturing has been successfully implemented in industries such as oil and gas and enhanced geothermal systems, and is currently being investigated as a potential method for preconditioning in mining. However, further research is required to quantify how hydraulic fractures propagate through hard, unfractured rock as well as naturally fractured rock typically found in mines. These in laboratory experiments will contribute to a hydraulic fracturing project evaluating the feasibility and effectiveness of hydraulic fracturing as a method of de-stressing hard rock mines. A tri-axial deformation cell equipped with 18 Acoustic Emission (AE) sensors will be used to bring the borehole cores to a tri-axial state of stress. The cores will then be injected with fluid until the the hydraulic fracture has propagated to the edge of the core, while AE waveforms will be digitized continuously at 10 MHz and 12-bit resolution for the duration of each experiment. These laboratory hydraulic fracture experiments will contribute to understanding how parameters including stress ratio, fluid injection rate, and viscosity, affect the fracturing process.

Use of variations in unit cell length, reflectance and hardness for determining the origin of Fe disulphides in sedimentary rocks

Science.gov (United States)

Dill, H. G.; Eberhard, E.; Hartmann, B.

1997-01-01

Fe disulphides are common opaque accessories in sedimentary rocks. Both marcasite and pyrite may shed some light on the depositional environment and help determine the diagenesis of their host rocks. Quantitative ore microscopy (reflectance measurements, Vickers hardness numbers) and X-ray diffraction methods, supplemented with scanning electron microscopy and chemical analyses, were applied to pyrite (and some marcasite) hosted by sedimentary rocks spanning the interval from the Devonian to the Pliocene, and formed in various marine and continental environments. Quantitative ore microscopy of pyrites of sedimentary origin does not seem to be an efficient tool for analyzing the environment owing to the inhomogeneous nature of sulphide aggregates when viewed under the ore microscope, and the variable amounts of minor elements (e.g., As, Ni, and Co) that control the reflectance values (RV) and Vickers hardness numbers (VHN) of the host sulphides. However, such parameters as crystal habit and unit cell length of pyrite, which correlate with FeS x, are useful for environmental analysis. The redox conditions and the presence of organic remains during formation are the main factors determining these crystallographic parameters. Differences in these parameters from those of pure, ideal FeS 2 can be related to substitution of, e.g., wustite in the pyrite lattice, reflecting moderate oxidation (i.e. in the microenvironment). As far as crystal habit and length of the cell edge are concerned, late stage diagenesis is obviously less important than the microenvironment attending initial formation. The environment of deposition (i.e. the macroenvironment) of pyrite-bearing rocks has no influence on the crystal morphology or the length of the unit cell of Fe disulphide. X-ray diffraction measurements demonstrate that this method provides useful evidence on the microenvironment of sulphide precipitation around a single, equant pyrite, as well as around pyritized fossils.

Centennial- to millennial-scale hard rock erosion rates deduced from luminescence-depth profiles

DEFF Research Database (Denmark)

Sohbati, Reza; Liu, Jinfeng; Jain, Mayank

2018-01-01

to quantify hard rock erosion rates at centennial to millennial timescales. Here we propose a novel technique, based on the solar bleaching of luminescence signals with depth into rock surfaces, to bridge this analytical gap. We apply our technique to glacial and landslide boulders in the Eastern Pamirs...

Hard-rock GMPEs versus Vs30-Kappa Host-to-Target Adjustment Techniques : Why so Large Differences in High Frequency Hard-Rock Motion ?

Science.gov (United States)

Bard, P. Y.; Laurendeau, A.; Hollender, F.; Perron, V.; Hernandez, B.; Foundotos, L.

2016-12-01

Assessment of local seismic hazard on hard rock sites (1000 processing of the Japanese KiK-net recordings from stiff sites (500 deep, within-motion to outcropping motion, or on a deconvolution of surface recordings using the velocity profile and 1D simulation, which has been performed both in the response spectrum and Fourier domains. Each of these virtual "outcropping hard-rock motion" data sets has then been used to derive GMPEs with simple functional forms, using as site condition proxy the S-wave velocity at depth (VSDH), ranging from 1000 to 3000 m/s. Both sets provide very similar predictions, which are much smaller at high frequencies (f > 10 Hz) than those estimated with the traditional HTTA technique - by a factor up to 3-4,. These differences decrease for decreasing frequency, and become negligible at low frequency (f shallow, moderate velocity layers. Not only this resonant amplification is not correctly accounted for by the quarter-wavelength approach used in the traditional HTTA adjustment techniques, but it may also significantly impact and bias the κ measurements, and the (VS30- κ0) relationships implicitly used in HTTA techniques.

Fracturing of hard rocks by microwave treatment and potential applications in mechanised tunnelling

OpenAIRE

YANLONG ZHENG

2018-01-01

Extremely hard and abrasive rocks have posed great challenges to mechanical excavators such as tunnel boring machines and roadheaders by increasing the cutter wear and decreasing the penetration rates. Microwave treatment prior to mechanical rock breakage has been recognised as a promising technology. This PhD project measures/derives the dielectric properties of commonly encountered rocks and minerals and investigates the effect of microwave treatment on the physical and mechanical propertie...

Geomechanics in hard rock mining-Lessons from two case histories

International Nuclear Information System (INIS)

Heuze, F.E.

1982-01-01

This paper summarizes the geomechanics programs conducted in two hard rock underground mining operations in the Western United States, between 1966 and 1981. The two projects were directed towards understanding the behavior of the rock masses, at the scale of the caverns. To this end, the emphasis was put on large scale field measurements, complemented by limited laboratory testing. The results of these observations were used to build realistic finite element models of the underground chambers. In the marble mine, at Crestmore, California, the models were applied to the structural optimization of the room-and-pillar pattern. In the granite mining, at Climax, Nevada Test Site, the models explained some unusual stress changes observed during excavation. Based on the large number of geomechanical techniques employed, specific conclusions and recommendations are offered regarding the quality, applicability, and usefulness of the various methods. The two case histories clearly indicate that numerical models are extremely useful for a detailed understanding of the structural behavior of mine openings. To be realistic, these models must be based first and foremost on large scale field observations. The lessons learned on these two projects also are directly applicable to the design and analysis of nuclear waste repositories in hard rocks such as basalt, granite, and welded tuff

Aespoe Hard Rock Laboratory. Annual report 1997

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-05-01

The Aespoe Hard Rock Laboratory has been constructed as part of the preparations for the deep geological repository for spent nuclear fuel in Sweden. The surface and borehole investigations and the research work performed in parallel with construction have provided a thorough test of methods for investigation and evaluation of bedrock conditions for construction of a deep repository. The Tracer Retention Understanding Experiments are made to gain a better understanding of radionuclide retention in the rock and create confidence in the radionuclide transport models that are intended to be used in the licensing of a deep repository for spent fuel. The experimental results of the first tracer test with sorbing radioactive tracers have been obtained. These tests have been subject to blind predictions by the Aespoe Task Force on groundwater flow and transports of solutes. The manufacturing of the CHEMLAB probe was completed during 1996, and the first experiments were started early in 1997. During 1997 three experiments on diffusion in bentonite using {sup 57}Co, {sup 114}Cs,{sup 85}Sr, {sup 99}Tc, and {sup 131}I were conducted. The Prototype Repository Test is focused on testing and demonstrating repository system function. A full scale prototype including six deposition holes with canisters with electric heaters surrounded by highly compacted bentonite will be built and instrumented. The characterization of the rock mass in the area of the prototype repository is in progress. The objectives of the Demonstration of Repository Technology are to develop, test, and demonstrate methodology and equipment for encapsulation and deposition of spent nuclear fuel. The demonstration of handling and deposition will be made in a new drift. The Backfill and Plug Test includes tests of backfill materials and emplacement methods and a test of a full scale plug. The backfill and rock will be instrumented with about 230 transducers for measuring the thermo-hydro-mechanical processes. The

Micro-computer cards for hard industrial environment

Energy Technology Data Exchange (ETDEWEB)

Breton, J M

1984-03-15

Approximately 60% of present or future distributed systems have, or will have, operational units installed in hard environments. In these applications, which include canalization and industrial motor control, robotics and process control, systems must be easily applied in environments not made for electronic use. The development of card systems in this hard industrial environment, which is found in petrochemical industry and mines is described. National semiconductor CIM card system CMOS technology allows the real time micro computer application to be efficient and functional in hard industrial environments.

On the Dynamics of Rocking Motion of the Hard-Disk Drive Spindle Motor System

Science.gov (United States)

Wang, Joseph

Excessive rocking motion of the spindle motor system can cause track misregistration resulting in poor throughput or even drive failure. The chance of excessive disk stack rocking increases as a result of decreasing torsional stiffness of spindle motor bearing system due to the market demand for low profile hard drives. As the track density increases and the vibration specification becomes increasingly stringent, rocking motion of a spindle motor system deserves even more attention and has become a primary challenge for a spindle motor system designer. Lack of understanding of the rocking phenomenon combined with misleading paradox has presented a great difficulty in the effort of avoiding the rocking motion in the hard-disk drive industry. This paper aims to provide fundamental understanding of the rocking phenomenon of a rotating spindle motor system, to clarify the paradox in disk-drive industry and to provide a design guide to an optimized spindle system. This paper, theoretically and experimentally, covers a few important areas of industrial interest including the prediction of rocking natural frequencies and mode shape of a rotating spindle, free vibration, and frequency response under common forcing functions such as rotating and fixed-plane forcing functions. The theory presented here meets with agreeable experimental observation.

New Rock Abrasivity Test Method for Tool Life Assessments on Hard Rock Tunnel Boring: The Rolling Indentation Abrasion Test (RIAT)

Science.gov (United States)

Macias, F. J.; Dahl, F.; Bruland, A.

2016-05-01

The tunnel boring machine (TBM) method has become widely used and is currently an important presence within the tunnelling industry. Large investments and high geological risk are involved using TBMs, and disc cutter consumption has a great influence on performance and cost, especially in hard rock conditions. Furthermore, reliable cutter life assessments facilitate the control of risk as well as avoiding delays and budget overruns. Since abrasive wear is the most common process affecting cutter consumption, good laboratory tests for rock abrasivity assessments are needed. A new abrasivity test method by rolling disc named Rolling Indentation Abrasion Test (RIAT) has been developed. The goal of the new test design and procedure is to reproduce wear behaviour on hard rock tunnel boring in a more realistic way than the traditionally used methods. Wear by rolling contact on intact rock samples is introduced and several rock types, covering a wide rock abrasiveness range, have been tested by RIAT. The RIAT procedure indicates a great ability of the testing method to assess abrasive wear on rolling discs. In addition and to evaluate the newly developed RIAT test method, a comprehensive laboratory testing programme including the most commonly used abrasivity test methods and the mineral composition were carried out. Relationships between the achieved results from conventional testing and RIAT results have been analysed.

Aespoe Hard Rock Laboratory. Annual report 1998

International Nuclear Information System (INIS)

1999-05-01

The Aespoe Hard Rock Laboratory has been constructed as part of the preparations for the deep geological repository for spent nuclear fuel in Sweden. The Tracer Retention Understanding Experiments are made to gain a better understanding of radionuclide retention in the rock and create confidence in the radionuclide transport models that are intended to be used in the licensing of a deep repository for spent fuel. Experiments with sorbing radioactive tracers have been completed in a single fracture over a distance of about 5 m. These tests have been subject to blind predictions by the Aespoe Task Force on groundwater flow and transports of solutes. Breakthrough of sorbing tracers in the TRUE-I tests is retarded more strongly than would be expected based on laboratory data alone. Results are consistent for all tracers and tracer tests. The main objective of the TRUE Block Scale Experiment is to increase understanding and our ability to predict tracer transport in a fracture network over spatial scales of 10 to 50 m. The total duration of the project is approximately 4.5 years with a scheduled finish at the end of the year 2000. The REX project focuses on the reduction of oxygen in a repository after closure due to reactions with rock minerals and microbial activity. Results show that oxygen is consumed within a few days both for the field and laboratory experiments. The project Degassing of groundwater and two phase flow was initiated to improve our understanding of observations of hydraulic conditions made in drifts and interpretation of experiments performed close to drifts. The analysis performed so far shows that the experimentally observed flow reductions indeed are consistent with the degassing hypothesis. The Prototype Repository Test is focused on testing and demonstrating repository system function. A full-scale prototype including six deposition holes with canisters with electric heaters surrounded by highly compacted bentonite will be built and

Aespoe Hard Rock Laboratory. Annual report 1998

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-05-01

The Aespoe Hard Rock Laboratory has been constructed as part of the preparations for the deep geological repository for spent nuclear fuel in Sweden. The Tracer Retention Understanding Experiments are made to gain a better understanding of radionuclide retention in the rock and create confidence in the radionuclide transport models that are intended to be used in the licensing of a deep repository for spent fuel. Experiments with sorbing radioactive tracers have been completed in a single fracture over a distance of about 5 m. These tests have been subject to blind predictions by the Aespoe Task Force on groundwater flow and transports of solutes. Breakthrough of sorbing tracers in the TRUE-I tests is retarded more strongly than would be expected based on laboratory data alone. Results are consistent for all tracers and tracer tests. The main objective of the TRUE Block Scale Experiment is to increase understanding and our ability to predict tracer transport in a fracture network over spatial scales of 10 to 50 m. The total duration of the project is approximately 4.5 years with a scheduled finish at the end of the year 2000. The REX project focuses on the reduction of oxygen in a repository after closure due to reactions with rock minerals and microbial activity. Results show that oxygen is consumed within a few days both for the field and laboratory experiments. The project Degassing of groundwater and two phase flow was initiated to improve our understanding of observations of hydraulic conditions made in drifts and interpretation of experiments performed close to drifts. The analysis performed so far shows that the experimentally observed flow reductions indeed are consistent with the degassing hypothesis. The Prototype Repository Test is focused on testing and demonstrating repository system function. A full-scale prototype including six deposition holes with canisters with electric heaters surrounded by highly compacted bentonite will be built and

Aespoe Hard Rock Laboratory. Planning Report for 2011

International Nuclear Information System (INIS)

2011-02-01

This report presents the planned activities for the year 2011. The report is revised annually and details the programme carried out in the Aespoe Hard Rock Laboratory as described in SKB's Research, Development and Demonstration Programme 2010, and serves as a basis for the management of the laboratory. The role of the Planning Report is to present the plans and scope of work for each project. Background information on the projects is given in the Annual Report as well as findings and results

The Fracture Influence on the Energy Loss of Compressed Air Energy Storage in Hard Rock

Directory of Open Access Journals (Sweden)

Hehua Zhu

2015-01-01

Full Text Available A coupled nonisothermal gas flow and geomechanical numerical modeling is conducted to study the influence of fractures (joints on the complex thermohydromechanical (THM performance of underground compressed air energy storage (CAES in hard rock caverns. The air-filled chamber is modeled as porous media with high porosity, high permeability, and high thermal conductivity. The present analysis focuses on the CAES in hard rock caverns at relatively shallow depth, that is, ≤100 m, and the pressure in carven is significantly higher than ambient pore pressure. The influence of one discrete crack and multiple crackson energy loss analysis of cavern in hard rock media are carried out. Two conditions are considered during each storage and release cycle, namely, gas injection and production mass being equal and additional gas injection supplemented after each cycle. The influence of the crack location, the crack length, and the crack open width on the energy loss is studied.

Evaluating the Relationships Between NTNU/SINTEF Drillability Indices with Index Properties and Petrographic Data of Hard Igneous Rocks

Science.gov (United States)

Aligholi, Saeed; Lashkaripour, Gholam Reza; Ghafoori, Mohammad; Azali, Sadegh Tarigh

2017-11-01

Thorough and realistic performance predictions are among the main requisites for estimating excavation costs and time of the tunneling projects. Also, NTNU/SINTEF rock drillability indices, including the Drilling Rate Index™ (DRI), Bit Wear Index™ (BWI), and Cutter Life Index™ (CLI), are among the most effective indices for determining rock drillability. In this study, brittleness value (S20), Sievers' J-Value (SJ), abrasion value (AV), and Abrasion Value Cutter Steel (AVS) tests are conducted to determine these indices for a wide range of Iranian hard igneous rocks. In addition, relationships between such drillability parameters with petrographic features and index properties of the tested rocks are investigated. The results from multiple regression analysis revealed that the multiple regression models prepared using petrographic features provide a better estimation of drillability compared to those prepared using index properties. Also, it was found that the semiautomatic petrography and multiple regression analyses provide a suitable complement to determine drillability properties of igneous rocks. Based on the results of this study, AV has higher correlations with studied mineralogical indices than AVS. The results imply that, in general, rock surface hardness of hard igneous rocks is very high, and the acidic igneous rocks have a lower strength and density and higher S20 than those of basic rocks. Moreover, DRI is higher, while BWI is lower in acidic igneous rocks, suggesting that drill and blast tunneling is more convenient in these rocks than basic rocks.

Aespoe Hard Rock Laboratory. Annual Report 2009

International Nuclear Information System (INIS)

2010-12-01

The Aespoe Hard Rock Laboratory (HRL) is an important part of SKB's work with the design and construction of a deep geological repository for the final disposal of spent nuclear fuel. Aespoe HRL is located in the Simpevarp area in the municipality of Oskarshamn. One of the fundamental reasons behind SKB's decision to construct an underground laboratory was to create opportunities for research, development and demonstration in a realistic and undisturbed rock environment down to repository depth. The underground part of the laboratory consists of a tunnel from the Simpevarp peninsula to the southern part of Aespoe where the tunnel continues in a spiral down to a depth of 460 m. Aespoe HRL has been in operation since 1995 and considerable international interest has been shown in its research, as well as in the development and demonstration tasks. A summary of the work performed at Aespoe HRL during 2009 is given below. Geoscience Geoscientific research is a basic activity at Aespoe HRL. The aim of the current studies is to develop geoscientific models of the Aespoe HRL and increase the understanding of the rock mass properties as well as knowledge of applicable methods of measurement. A main task within the geoscientific field is the development of the Aespoe Site Descriptive Model (SDM) integrating information from the different fields. The main activities in the geoscientific fields have been: (1) Geology evaluation of geological mapping techniques leading to the decision to develop a SKB mapping system and finalization of the mapping of rock surfaces in the new tunnel, (2) Hydrogeology monitoring and storage of data in the computerised Hydro Monitoring System, (3) Geochemistry sampling of groundwater in the yearly campaign and for specific experiments and (4) Rock Mechanics finalised the field tests on thermally-induced spalling in deposition holes and evaluated the effect of counterforce in the deposition holes. Natural barriers At Aespoe HRL, experiments are

Aespoe Hard Rock Laboratory. Annual Report 2009

Energy Technology Data Exchange (ETDEWEB)

2010-12-15

The Aespoe Hard Rock Laboratory (HRL) is an important part of SKB's work with the design and construction of a deep geological repository for the final disposal of spent nuclear fuel. Aespoe HRL is located in the Simpevarp area in the municipality of Oskarshamn. One of the fundamental reasons behind SKB's decision to construct an underground laboratory was to create opportunities for research, development and demonstration in a realistic and undisturbed rock environment down to repository depth. The underground part of the laboratory consists of a tunnel from the Simpevarp peninsula to the southern part of Aespoe where the tunnel continues in a spiral down to a depth of 460 m. Aespoe HRL has been in operation since 1995 and considerable international interest has been shown in its research, as well as in the development and demonstration tasks. A summary of the work performed at Aespoe HRL during 2009 is given below. Geoscience Geoscientific research is a basic activity at Aespoe HRL. The aim of the current studies is to develop geoscientific models of the Aespoe HRL and increase the understanding of the rock mass properties as well as knowledge of applicable methods of measurement. A main task within the geoscientific field is the development of the Aespoe Site Descriptive Model (SDM) integrating information from the different fields. The main activities in the geoscientific fields have been: (1) Geology evaluation of geological mapping techniques leading to the decision to develop a SKB mapping system and finalization of the mapping of rock surfaces in the new tunnel, (2) Hydrogeology monitoring and storage of data in the computerised Hydro Monitoring System, (3) Geochemistry sampling of groundwater in the yearly campaign and for specific experiments and (4) Rock Mechanics finalised the field tests on thermally-induced spalling in deposition holes and evaluated the effect of counterforce in the deposition holes. Natural barriers At Aespoe HRL

Aespoe Hard Rock Laboratory. Planning Report for 2011

Energy Technology Data Exchange (ETDEWEB)

2011-02-15

This report presents the planned activities for the year 2011. The report is revised annually and details the programme carried out in the Aespoe Hard Rock Laboratory as described in SKB's Research, Development and Demonstration Programme 2010, and serves as a basis for the management of the laboratory. The role of the Planning Report is to present the plans and scope of work for each project. Background information on the projects is given in the Annual Report as well as findings and results.

Thermal aspects of radioactive waste disposal in hard rock

International Nuclear Information System (INIS)

Beale, H.; Bourke, P.J.; Hodgkinson, D.P.

1980-01-01

Buried heat emitting radioactive waste will appreciably raise the temperature of the surrounding rock over distances of several hundred metres for many centuries. This paper describes continuing research at Harwell aimed at understanding how this heating affects the design of hard rock depositories for the waste. It also considers how water-borne leakage of radionuclides from a depository to the surface might be increased by thermal convection currents through the rock mass and by thermally induced changes in its permeability and porosity. A conceptual design for a three-dimensional depository with an array of vitrified waste blocks placed in vertical boreholes is described. The maximum permissible power outputs of individual blocks and the minimum permissible separations between blocks to limit the local and bulk average rock temperatures will be determined by heat transfer through the rock and are reviewed. Interim results of a field heating experiment to study transient heat transfer through granite are discussed subsequently. Field experiments are now being started to measure the fracture permeability and porosity over large distances in virgin granite and to investigate their variation on heating and cooling the rock. Theoretical estimates of the temperatures, thermal stresses and thermal convection currents around a depository are next presented. The implications for water-borne leakage are that the induced stresses could change the fracture permeability and porosity, and thermal convection could cause substantial water movement vertically towards the surface. Finally some conclusions from the work are presented. (author)

Measurements of copper corrosion in the LOT Project at the Aespoe Hard Rock Laboratory

International Nuclear Information System (INIS)

Rosborg, B.; Karnland, O.; Quirk, G.; Werme, L.

2003-01-01

Real-time monitoring, of corrosion by means of electrochemical noise and other electrochemical techniques may offer interesting possibilities to estimate the kind and degree of corrosion in a sample or component, and further visualize the corrosion resistance of pure copper in repository environments. As a pilot effort, three cylindrical copper electrodes for such measurements, each of about 100 cm 2 surface area, have been installed in a test parcel in the Aespoe Hard Rock Laboratory and electrochemical measurements using InterCorr's SmartCET system were initiated in May 2001. The first results from real-time monitoring of copper corrosion in the Aespoe HRL under actual repository environment conditions by means of linear polarisation resistance, harmonic distortion analysis and electrochemical noise techniques are presented, and compared with the results obtained from one of the retrieved test parcels. (authors)

The Leeb Hardness Test for Rock: An Updated Methodology and UCS Correlation

Science.gov (United States)

Corkum, A. G.; Asiri, Y.; El Naggar, H.; Kinakin, D.

2018-03-01

The Leeb hardness test (LHT with test value of L D ) is a rebound hardness test, originally developed for metals, that has been correlated with the Unconfined Compressive Strength (test value of σ c ) of rock by several authors. The tests can be carried out rapidly, conveniently and nondestructively on core and block samples or on rock outcrops. This makes the relatively small LHT device convenient for field tests. The present study compiles test data from literature sources and presents new laboratory testing carried out by the authors to develop a substantially expanded database with wide-ranging rock types. In addition, the number of impacts that should be averaged to comprise a "test result" was revisited along with the issue of test specimen size. Correlation for L D and σ c for various rock types is provided along with recommended testing methodology. The accuracy of correlated σ c estimates was assessed and reasonable correlations were observed between L D and σ c . The study findings show that LHT can be useful particularly for field estimation of σ c and offers a significant improvement over the conventional field estimation methods outlined by the ISRM (e.g., hammer blows). This test is rapid and simple, with relatively low equipment costs, and provides a reasonably accurate estimate of σ c .

Experiments at the Aespoe Hard Rock Laboratory[Information for the general public

Energy Technology Data Exchange (ETDEWEB)

NONE

2004-12-01

A dress rehearsal is being held in preparation for the construction of a deep repository for spent nuclear fuel at SKB's underground Hard Rock Laboratory (HRL) on Aespoe, outside Oskarshamn. Here we can test different technical solutions on a full scale and in a realistic environment. The Aespoe HRL is also used for field research. We are conducting a number of experiments here in collaboration with Swedish and international experts. In the Zedex experiment we have compared how the rock is affected around a drill-and-blast tunnel versus a bored tunnel. In a new experiment we will investigate how much the rock can take. A narrow pillar between two boreholes will be loaded to the point that the rock's ultimate strength is exceeded (Aespoe Pillar Stability Experiment). In the Demo Test we are demonstrating emplacement of the copper canisters and the surrounding bentonite in the deposition holes. In the Prototype Repository we study what long-term changes occur in the barriers under the conditions prevailing in a deep repository. Horizontal deposition: Is it possible to deposit the canisters horizontally without compromising safety? Backfill and Plug Test: The tunnels in the future deep repository for spent nuclear fuel will be filled with clay and crushed rock and then plugged. Canister Retrieval Test: If the deep repository should not perform satisfactorily for some reason, we want to be able to retrieve the spent fuel. The Lot test is intended to show how the bentonite behaves in an environment similar to that in the future deep repository. The purpose of the TBT test is to determine how the bentonite clay in the buffer is affected by high temperatures. Two-phase flow means that liberated gas in the groundwater flows separately in the fractures in the rock. This reduces the capacity of the rock to conduct water. Lasgit: By pressurizing a canister with helium, we can measure how the gas moves through the surrounding buffer. Colloid Project: Can very small

Aespoe Hard Rock Laboratory. Planning Report for 2009

Energy Technology Data Exchange (ETDEWEB)

2009-02-15

This report presents the planned activities for the year 2009. The report is revised annually and details the programme carried out in the Aespoe Hard Rock Laboratory as described in SKB's Research, Development and Demonstration Programme 2007, and serves as a basis for the management of the laboratory. The role of the Planning Report is to present the plans and scope of work for each project. Thereby the Status Reports may concentrate on work in progress and refers to this Planning Report for scope of work over the year. Background information on the projects is given in the Annual Report as well as findings and results.

Aespoe Hard Rock Laboratory. Planning Report for 2010

Energy Technology Data Exchange (ETDEWEB)

2010-05-15

This report presents the planned activities for the year 2010. The report is revised annually and details the programme carried out in the Aespoe Hard Rock Laboratory as described in SKB's Research, Development and Demonstration Programme 2007, and serves as a basis for the management of the laboratory. The role of the Planning Report is to present the plans and scope of work for each project. Thereby the Status Reports may concentrate on work in progress and refers to this Planning Report for scope of work over the year. Background information on the projects is given in the Annual Report as well as findings and results

Aespoe Hard Rock Laboratory. Planning Report for 2009

International Nuclear Information System (INIS)

2009-02-01

This report presents the planned activities for the year 2009. The report is revised annually and details the programme carried out in the Aespoe Hard Rock Laboratory as described in SKB's Research, Development and Demonstration Programme 2007, and serves as a basis for the management of the laboratory. The role of the Planning Report is to present the plans and scope of work for each project. Thereby the Status Reports may concentrate on work in progress and refers to this Planning Report for scope of work over the year. Background information on the projects is given in the Annual Report as well as findings and results

Aespoe Hard Rock Laboratory. Planning Report for 2010

International Nuclear Information System (INIS)

2010-05-01

This report presents the planned activities for the year 2010. The report is revised annually and details the programme carried out in the Aespoe Hard Rock Laboratory as described in SKB's Research, Development and Demonstration Programme 2007, and serves as a basis for the management of the laboratory. The role of the Planning Report is to present the plans and scope of work for each project. Thereby the Status Reports may concentrate on work in progress and refers to this Planning Report for scope of work over the year. Background information on the projects is given in the Annual Report as well as findings and results

Deciphering groundwater potential zones in hard rock terrain using geospatial technology.

Science.gov (United States)

Dar, Imran A; Sankar, K; Dar, Mithas A

2011-02-01

Remote sensing and geographical information system (GIS) has become one of the leading tools in the field of groundwater research, which helps in assessing, monitoring, and conserving groundwater resources. This paper mainly deals with the integrated approach of remote sensing and GIS to delineate groundwater potential zones in hard rock terrain. Digitized vector maps pertaining to chosen parameters, viz. geomorphology, geology, land use/land cover, lineament, relief, and drainage, were converted to raster data using 23 m×23 m grid cell size. Moreover, curvature of the study area was also considered while manipulating the spatial data. The raster maps of these parameters were assigned to their respective theme weight and class weights. The individual theme weight was multiplied by its respective class weight and then all the raster thematic layers were aggregated in a linear combination equation in Arc Map GIS Raster Calculator module. Moreover, the weighted layers were statistically modeled to get the areal extent of groundwater prospects with respect to each thematic layer. The final result depicts the favorable prospective zones in the study area and can be helpful in better planning and management of groundwater resources especially in hard rock terrains.

Initial assessment of the thermal stresses around a radioactive waste depository in hard rock

International Nuclear Information System (INIS)

Hodgkinson, D.P.; Bourke, P.J.

1980-01-01

The disposal of heat emitting radioactive waste into hard rock should result in temperature rises and thermal gradients over distances of several hundred metres for several centuries. The consequent constrained thermal expansion of the rock would induce stresses which have important implications for possible water-borne leakage of radionuclides and for depository design. These problems are assessed by considering a simplified mathematical model for which analytic solutions to the temperature and stress fields are derived. (author)

Hydrogeophysics and remote sensing for the design of hydrogeological conceptual models in hard rocks - Sardón catchment (Spain)

OpenAIRE

Francés, Alain; Lubczynski, Maciek W.; Roy, Jean; Santos, Fernando A. Monteiro; Ardekani, Mohammad R. Mahmoudzadeh

2014-01-01

Hard rock aquifers are highly heterogeneous and hydrogeologically complex. To contribute to the design of hydrogeological conceptual models of hard rock aquifers, we propose a multi-techniques methodology based on a downward approach that combines remote sensing (RS), non-invasive hydrogeophysics and hydrogeological field data acquisition. The proposed methodology is particularly suitable for data scarce areas. It was applied in the pilot research area of Sardón catchment (80 km2)...

Aespoe Hard Rock Laboratory. Status Report May - August 2009

International Nuclear Information System (INIS)

2009-11-01

The Aespoe Hard Rock Laboratory (HRL) constitutes an important part of SKB's work to design and construct a geological repository for spent nuclear fuel and to develop and test methods for characterisation of a suitable site. The plans for SKB's research and development of technique during the period 2008-2013 are presented in SKB's RDandD-Programme 2007 /SKB 2007/. The information given in the RDandD-Programme related to Aespoe HRL is annually detailed in the Aespoe HRL Planning Report /SKB 2009/. This Aespoe HRL Status Report is a collection of the main achievements obtained during the period May to August 2009

Aespoe Hard Rock Laboratory. Status Report October - December 2008

International Nuclear Information System (INIS)

2009-03-01

The Aespoe Hard Rock Laboratory (HRL) constitutes an important part of SKB's work to design and construct a geological repository for spent nuclear fuel and to develop and test methods for characterisation of a suitable site. The plans for SKB's research and development of technique during the period 2008-2013 are presented in SKB's RDandD-Programme 2007 /SKB 2007/. The information given in the RDandD-Programme related to Aespoe HRL is annually detailed in the Aespoe HRL Planning Report /SKB 2008/. This Aespoe HRL Status Report is a collection of the main achievements obtained during the fourth quarter of 2008

Aespoe Hard Rock Laboratory. Status Report. September - December 2009

International Nuclear Information System (INIS)

2010-05-01

The Aespoe Hard Rock Laboratory (HRL) constitutes an important part of SKB's work to design and construct a geological repository for spent nuclear fuel and to develop and test methods for characterisation of a suitable site. The plans for SKB's research and development of technique during the period 2008-2013 are presented in SKB's RDandD Programme 2007 /SKB 2007/. The information given in the RDandD-Programme related to Aespoe HRL is annually detailed in the Aespoe HRL Planning Report /SKB 2009/. This Aespoe HRL Status Report is a collection of the main achievements obtained during the period September to December 2009

Aespoe Hard Rock Laboratory. Status Report January - April 2009

International Nuclear Information System (INIS)

2009-09-01

The Aespoe Hard Rock Laboratory (HRL) constitutes an important part of SKB's work to design and construct a geological repository for spent nuclear fuel and to develop and test methods for characterisation of a suitable site. The plans for SKB's research and development of technique during the period 2008-2013 are presented in SKB's RDandD-Programme 2007 /SKB 2007/. The information given in the RDandD-Programme related to Aespoe HRL is annually detailed in the Aespoe HRL Planning Report /SKB 2009/. This Aespoe HRL Status Report is a collection of the main achievements obtained during the period January to April 2009

Aespoe Hard Rock Laboratory. Status Report. April - June 2007

Energy Technology Data Exchange (ETDEWEB)

2007-07-01

The Aespoe Hard Rock Laboratory (HRL) constitutes an important part of SKB's work to design and construct a geological repository for spent nuclear fuel and to develop and test methods for characterisation of a suitable site. The plans for SKB's research and development of technique during the period 2005- 2010 are presented in SKB's RDandD-Programme 2004 /SKB 2004/. The information given in the RDandD-Programme related to Aespoe HRL is annually detailed in the Aespoe HRL Planning Report /SKB 2007/. This Aespoe HRL Status Report is a collection of the main achievements obtained during the second quarter 2007

Aespoe Hard Rock Laboratory. Status Report. April - June 2007

International Nuclear Information System (INIS)

2007-01-01

The Aespoe Hard Rock Laboratory (HRL) constitutes an important part of SKB's work to design and construct a geological repository for spent nuclear fuel and to develop and test methods for characterisation of a suitable site. The plans for SKB's research and development of technique during the period 2005- 2010 are presented in SKB's RDandD-Programme 2004 /SKB 2004/. The information given in the RDandD-Programme related to Aespoe HRL is annually detailed in the Aespoe HRL Planning Report /SKB 2007/. This Aespoe HRL Status Report is a collection of the main achievements obtained during the second quarter 2007

Aespoe Hard Rock Laboratory. Status Report. July - September 2008

International Nuclear Information System (INIS)

2008-01-01

The Aespoe Hard Rock Laboratory (HRL) constitutes an important part of SKB's work to design and construct a geological repository for spent nuclear fuel and to develop and test methods for characterisation of a suitable site. The plans for SKB's research and development of technique during the period 2008-2013 are presented in SKB's RDandD-Programme 2007 /SKB 2007/. The information given in the RDandD-Programme related to Aespoe HRL is annually detailed in the Aespoe HRL Planning Report /SKB 2008/. This Aespoe HRL Status Report is a collection of the main achievements obtained during the third quarter of 2008

Aespoe Hard Rock Laboratory. Status Report. January - April 2010

International Nuclear Information System (INIS)

2010-10-01

The Aespoe Hard Rock Laboratory (HRL) constitutes an important part of SKB's work to design and construct a geological repository for spent nuclear fuel and to develop and test methods for characterisation of a suitable site. The plans for SKB's research and development of technique during the period 2008-2013 are presented in SKB's RDandD Programme 2007 /SKB 2007/. The information given in the RDandD-Programme related to Aespoe HRL is annually detailed in the Aespoe HRL Planning Report /SKB 2009/. This Aespoe HRL Status Report is a collection of the main achievements obtained during the period January to April 2010

Aespoe Hard Rock Laboratory. Annual Report 2002

Energy Technology Data Exchange (ETDEWEB)

NONE

2006-06-15

The Aespoe Hard Rock Laboratory (HRL), in the Simpevarp area in the municipality of Oskarshamn constitutes an important part of SKB's work with the design and construction of a deep geological repository for final disposal of spent nuclear fuel. One of the fundamental reasons behind SKB's decision to construct an underground laboratory was to create an opportunity for research, development and demonstration in a realistic and undisturbed rock environment down to repository depth. The underground part of the laboratory consists of a tunnel from the Simpevarp peninsula to the southern part of Aespoe where the tunnel continues in a spiral down to a depth of 460 m. Aespoe HRL has been in operation since 1995 and considerable international interest has been shown in its associated research, as well as in the development and demonstration tasks. Most of the research is focused on processes of importance for the long-term safety of a final repository for spent nuclear fuel. Demonstration addresses the performance of the engineered barriers and practical means of constructing and operating a repository for spent fuel. To meet the overall time schedule for SKB's RD and D work, the following stage goals were initially defined for the work at the Aespoe HRL: 1. Verify pre-investigation methods. Demonstrate that investigations on the ground surface and in boreholes provide sufficient data on essential safety-related properties of the rock at repository level. 2. Finalise detailed investigation methodology. Refine and verify the methods and the technology needed for characterisation of the rock in the detailed site investigations. 3. Test models for description of the barrier functions at natural conditions. Further develop, and at repository depth, test methods and models for description of groundwater flow, radionuclide migration and chemical conditions during operation of a repository and after closure. 4. Demonstrate technology for and function of important

Aespoe Hard Rock Laboratory. Annual Report 2005

International Nuclear Information System (INIS)

2006-06-01

The Aespoe Hard Rock Laboratory (HRL), in the Simpevarp area in the municipality of Oskarshamn constitutes an important part of SKB's work with the design and construction of a deep geological repository for final disposal of spent nuclear fuel. One of the fundamental reasons behind SKB's decision to construct an underground laboratory was to create an opportunity for research, development and demonstration in a realistic and undisturbed rock environment down to repository depth. The underground part of the laboratory consists of a tunnel from the Simpevarp peninsula to the southern part of Aespoe where the tunnel continues in a spiral down to a depth of 460 m. Aespoe HRL has been in operation since 1995 and considerable international interest has been shown in its associated research, as well as in the development and demonstration tasks. Most of the research is focused on processes of importance for the long-term safety of a final repository for spent nuclear fuel. Demonstration addresses the performance of the engineered barriers and practical means of constructing and operating a repository for spent fuel. To meet the overall time schedule for SKB's RD and D work, the following stage goals were initially defined for the work at the Aespoe HRL: 1. Verify pre-investigation methods. Demonstrate that investigations on the ground surface and in boreholes provide sufficient data on essential safety-related properties of the rock at repository level. 2. Finalise detailed investigation methodology. Refine and verify the methods and the technology needed for characterisation of the rock in the detailed site investigations. 3. Test models for description of the barrier functions at natural conditions. Further develop, and at repository depth, test methods and models for description of groundwater flow, radionuclide migration and chemical conditions during operation of a repository and after closure. 4. Demonstrate technology for and function of important parts of the

Recent development in the design of hard rock tunnel boring machines for the mining industry

International Nuclear Information System (INIS)

Snyder, L.L.; Williams, R.I.

1991-01-01

Underground development for nuclear waste storage will possibly require tunnels to be excavated in a variety of rock conditions and configurations. Recent innovations in Tunnel Boring Machine (TBM) design have allowed for an evolved style of TBM which has distinct advantages over the standard machines. Present day conventional hard rock TBM's were developed primarily for the long, relatively straight tunnels of the civil construction industry, thereby making them for the most part, unsuitable for the sharp curves, turnouts, declines, inclines and ramps required in many underground environments. The five foot to 36 foot (1.52 to 11 m) diameter machines are capable of boring tunnels with curve radiuses as small as 40 to 90 feet (12.2 to 27.5 m) depending on size. These short turning radiuses can be accomplished while gripping the tunnel walls horizontally in the traditional manner or vertically as required when intersecting existing tunnels, or making turnouts from the tunnel that the machine has just bored. The machine's length is approximately half of a traditional machine's length while still employing a full measure of thrust, horsepower and rock cutting ability. The machine's short length, combined with a patented machine structure allows it to steer while boring without causing harmful eccentric loads on the cutterhead and main bearing assembly. The machine configuration is versatile and can be easily modified to operate in a wide variety of conditions

Aespoe Hard Rock Laboratory. Overview of the investigations 1986-1990

International Nuclear Information System (INIS)

Stanfors, R.; Erlstroem, M.; Markstroem, I.

1991-06-01

In order to prepare for the siting and licensing of a spent fuel repository SKB has decided to construct a new underground research laboratory. The pre-investigations for the Aespoe Hard Rock Laboratory started in late 1986. This report gives a comprehensive compilation of the different investigations performed during the pre-investigation phase (1986-1990). The information is mainly compiled in CAD-generated maps and illustrations in which the reader can gather information concerning the scope of work as well as references to more detailed reports for further study. (au)

The automation of the "making safe" process in South African hard-rock underground mine

CSIR Research Space (South Africa)

Teleka, SR

2011-07-01

Full Text Available In South African hard-rock mines, best practice dictates that the hanging-walls be inspected after blasting. This process is known as ‘making safe’ and although intended to save lives, it is laborious and subjective. Pressure is placed on the barrer...

Coupled Hydro-Economic Dynamics of Groundwater Irrigated Agriculture in a Hard Rock Region of India

Science.gov (United States)

Modi, V.; Fishman, R.; Siegfried, T. U.; Raj, P.; Vasquez, V.; Narula, K.; Lall, U.

2009-12-01

We analyze the dynamics of groundwater and irrigated agriculture in a semi-arid, hard rock region of India, which is characterized by low-yield, limited storativity aquifers. Telengana, in western Andhra Pradesh has witnessed a relentless expansion of the total irrigated area. Total crop irrigation water requirements have increased by more than 50 percent over the last 30 years. Nowadays, more than 80 percent of the net irrigated area in the region is irrigated from groundwater. Given limited, period monsoonal recharge to the aquifers, it can be estimated that groundwater irrigation intensity is surpassing sustainable allocation levels by a factor of 3. It is not further surprising that the region is increasingly affected by widespread groundwater depletion, with negative consequences for farmers and the energy sector as well as the natural environment. Using data on water tables, precipitation and agricultural land use, we show how both rainfall and farmers’ choices effect water tables and how these, in turn, re-effect farmers choices and agricultural outcomes in a dynamic relationship that allows us to model the interaction between the natural hydrological and agricultural-social dynamics. We use the model to elucidate and quantify the meaning of groundwater mining in this hard rock environment. In contrast to deep alluvial aquifers, excessive extraction does not lead to sustained long term deepening of the water table, but to increased fluctuations in the supply of groundwater for irrigation and the loss of the buffering capacity. For the farmers, this potentially translates into increasingly perilous agricultural production outcomes during monsoonal failures. Furthermore, the dry season agricultural production that entirely depends on the availability of sufficient amounts of irrigation water is progressively threatened under the current allocation scenario. Alternative management practices to address the aquifer depletion issues are discussed. We show that

Aespoe Hard Rock Laboratory. Status Report January - April 2009

Energy Technology Data Exchange (ETDEWEB)

2009-09-15

The Aespoe Hard Rock Laboratory (HRL) constitutes an important part of SKB's work to design and construct a geological repository for spent nuclear fuel and to develop and test methods for characterisation of a suitable site. The plans for SKB's research and development of technique during the period 2008-2013 are presented in SKB's RDandD-Programme 2007 /SKB 2007/. The information given in the RDandD-Programme related to Aespoe HRL is annually detailed in the Aespoe HRL Planning Report /SKB 2009/. This Aespoe HRL Status Report is a collection of the main achievements obtained during the period January to April 2009.

Aespoe Hard Rock Laboratory. Status Report October - December 2008

Energy Technology Data Exchange (ETDEWEB)

2009-03-15

The Aespoe Hard Rock Laboratory (HRL) constitutes an important part of SKB's work to design and construct a geological repository for spent nuclear fuel and to develop and test methods for characterisation of a suitable site. The plans for SKB's research and development of technique during the period 2008-2013 are presented in SKB's RDandD-Programme 2007 /SKB 2007/. The information given in the RDandD-Programme related to Aespoe HRL is annually detailed in the Aespoe HRL Planning Report /SKB 2008/. This Aespoe HRL Status Report is a collection of the main achievements obtained during the fourth quarter of 2008.

Aespoe Hard Rock Laboratory. Status Report. September - December 2009

Energy Technology Data Exchange (ETDEWEB)

2010-05-15

The Aespoe Hard Rock Laboratory (HRL) constitutes an important part of SKB's work to design and construct a geological repository for spent nuclear fuel and to develop and test methods for characterisation of a suitable site. The plans for SKB's research and development of technique during the period 2008-2013 are presented in SKB's RDandD Programme 2007 /SKB 2007/. The information given in the RDandD-Programme related to Aespoe HRL is annually detailed in the Aespoe HRL Planning Report /SKB 2009/. This Aespoe HRL Status Report is a collection of the main achievements obtained during the period September to December 2009

Aespoe Hard Rock Laboratory. Status Report. January - April 2010

Energy Technology Data Exchange (ETDEWEB)

2010-10-15

The Aespoe Hard Rock Laboratory (HRL) constitutes an important part of SKB's work to design and construct a geological repository for spent nuclear fuel and to develop and test methods for characterisation of a suitable site. The plans for SKB's research and development of technique during the period 2008-2013 are presented in SKB's RDandD Programme 2007 /SKB 2007/. The information given in the RDandD-Programme related to Aespoe HRL is annually detailed in the Aespoe HRL Planning Report /SKB 2009/. This Aespoe HRL Status Report is a collection of the main achievements obtained during the period January to April 2010

Aespoe Hard Rock Laboratory. Status Report May - August 2009

Energy Technology Data Exchange (ETDEWEB)

2009-11-15

The Aespoe Hard Rock Laboratory (HRL) constitutes an important part of SKB's work to design and construct a geological repository for spent nuclear fuel and to develop and test methods for characterisation of a suitable site. The plans for SKB's research and development of technique during the period 2008-2013 are presented in SKB's RDandD-Programme 2007 /SKB 2007/. The information given in the RDandD-Programme related to Aespoe HRL is annually detailed in the Aespoe HRL Planning Report /SKB 2009/. This Aespoe HRL Status Report is a collection of the main achievements obtained during the period May to August 2009.

Aespoe Hard Rock Laboratory. Status Report May - August 2010

Energy Technology Data Exchange (ETDEWEB)

2011-02-15

The Aespoe Hard Rock Laboratory (HRL) constitutes an important part of SKB's work to design and construct a geological repository for spent nuclear fuel and to develop and test methods for characterisation of a suitable site. The plans for SKB's research and development of technique during the period 2008-2013 are presented in SKB's RDandD-Programme 2007 /SKB 2007/. The information given in the RD and D-Programme related to Aespoe HRL is annually detailed in the Aespoe HRL Planning Report /SKB 2010/. This Aespoe HRL Status Report is a collection of the main achievements obtained during the period May to August 2010.

Aespoe Hard Rock Laboratory. Status Report. April - June 2007

Energy Technology Data Exchange (ETDEWEB)

2007-07-01

The Aespoe Hard Rock Laboratory (HRL) constitutes an important part of SKB's work to design and construct a geological repository for spent nuclear fuel and to develop and test methods for characterisation of a suitable site. The plans for SKB's research and development of technique during the period 2005- 2010 are presented in SKB's RDandD-Programme 2004 /SKB 2004/. The information given in the RDandD-Programme related to Aespoe HRL is annually detailed in the Aespoe HRL Planning Report /SKB 2007/. This Aespoe HRL Status Report is a collection of the main achievements obtained during the second quarter 2007

Aespoe Hard Rock Laboratory. Status Report May - August 2010

International Nuclear Information System (INIS)

2011-02-01

The Aespoe Hard Rock Laboratory (HRL) constitutes an important part of SKB's work to design and construct a geological repository for spent nuclear fuel and to develop and test methods for characterisation of a suitable site. The plans for SKB's research and development of technique during the period 2008-2013 are presented in SKB's RDandD-Programme 2007 /SKB 2007/. The information given in the RD and D-Programme related to Aespoe HRL is annually detailed in the Aespoe HRL Planning Report /SKB 2010/. This Aespoe HRL Status Report is a collection of the main achievements obtained during the period May to August 2010

Aespoe Hard Rock Laboratory. Status Report. July - September 2008

Energy Technology Data Exchange (ETDEWEB)

2008-07-01

The Aespoe Hard Rock Laboratory (HRL) constitutes an important part of SKB's work to design and construct a geological repository for spent nuclear fuel and to develop and test methods for characterisation of a suitable site. The plans for SKB's research and development of technique during the period 2008-2013 are presented in SKB's RDandD-Programme 2007 /SKB 2007/. The information given in the RDandD-Programme related to Aespoe HRL is annually detailed in the Aespoe HRL Planning Report /SKB 2008/. This Aespoe HRL Status Report is a collection of the main achievements obtained during the third quarter of 2008.

Aespoe Hard Rock Laboratory. BIPS logging in borehole KAS09

Energy Technology Data Exchange (ETDEWEB)

Gustafsson, Jaana; Gustafsson, Christer (Malaa Geoscience AB (Sweden))

2010-01-15

This report includes the data gained in BIPS logging performed at the Aespoe Hard Rock Laboratory. The logging operation presented here includes BIPS logging in the core drilled borehole KAS09. The objective for the BIPS logging was to observe the condition of KAS09 in order to restore the borehole in the hydrogeological monitoring programme.All measurements were conducted by Malaa Geoscience AB on October 9th 2009. The objective of the BIPS logging is to achieve information of the borehole including occurrence of rock types as well as determination of fracture distribution and orientation. This report describes the equipment used as well as the measurement procedures and data gained. For the BIPS survey, the result is presented as images. The basic conditions of the BIPS logging for geological mapping and orientation of structures are satisfying for borehole KAS09, although induced affects from the drilling on the borehole walls limit the visibility

Aespoe Hard Rock Laboratory. BIPS logging in borehole KAS09

International Nuclear Information System (INIS)

Gustafsson, Jaana; Gustafsson, Christer

2010-01-01

This report includes the data gained in BIPS logging performed at the Aespoe Hard Rock Laboratory. The logging operation presented here includes BIPS logging in the core drilled borehole KAS09. The objective for the BIPS logging was to observe the condition of KAS09 in order to restore the borehole in the hydrogeological monitoring programme.All measurements were conducted by Malaa Geoscience AB on October 9th 2009. The objective of the BIPS logging is to achieve information of the borehole including occurrence of rock types as well as determination of fracture distribution and orientation. This report describes the equipment used as well as the measurement procedures and data gained. For the BIPS survey, the result is presented as images. The basic conditions of the BIPS logging for geological mapping and orientation of structures are satisfying for borehole KAS09, although induced affects from the drilling on the borehole walls limit the visibility

Aespoe Hard Rock Laboratory. Prototype Repository. Acoustic emission and ultrasonic monitoring results from deposition hole DA3545G01 in the Prototype Repository between October 2007 and March 2008

Energy Technology Data Exchange (ETDEWEB)

Duckworth, D.; Haycox, J.; Pettitt, W.S. (Applied Seismology Consultants, Shrewsbury (United Kingdom))

2008-12-15

This report describes results from acoustic emission (AE) and ultrasonic monitoring around a canister deposition hole (DA3545G01) in the Prototype Repository Experiment at SKB's Hard Rock Laboratory (HRL), Sweden. The experiment has been designed to simulate a disposal tunnel in a real deep repository environment for storage of high-level radioactive waste. The test consists of a 90 m long, 5 m diameter subhorizontal tunnel excavated in dioritic granite. The monitoring aims to examine changes in the rock mass caused by an experimental repository environment, in particular due to thermal stresses induced from canister heating and pore pressures induced from tunnel sealing.

Aespoe Hard Rock Laboratory. Prototype Repository. Acoustic emission and ultrasonic monitoring results from deposition hole DA3545G01 in the Prototype Repository between October 2007 and March 2008

International Nuclear Information System (INIS)

Duckworth, D.; Haycox, J.; Pettitt, W.S.

2008-12-01

This report describes results from acoustic emission (AE) and ultrasonic monitoring around a canister deposition hole (DA3545G01) in the Prototype Repository Experiment at SKB's Hard Rock Laboratory (HRL), Sweden. The experiment has been designed to simulate a disposal tunnel in a real deep repository environment for storage of high-level radioactive waste. The test consists of a 90 m long, 5 m diameter subhorizontal tunnel excavated in dioritic granite. The monitoring aims to examine changes in the rock mass caused by an experimental repository environment, in particular due to thermal stresses induced from canister heating and pore pressures induced from tunnel sealing

The use of magnetic resonance sounding for quantifying specific yield and transmissivity in hard rock aquifers: The example of Benin

Science.gov (United States)

Vouillamoz, J. M.; Lawson, F. M. A.; Yalo, N.; Descloitres, M.

2014-08-01

Hundreds of thousands of boreholes have been drilled in hard rocks of Africa and Asia for supplying human communities with drinking water. Despite the common use of geophysics for improving the siting of boreholes, a significant number of drilled holes does not deliver enough water to be equipped (e.g. 40% on average in Benin). As compared to other non-invasive geophysical methods, magnetic resonance sounding (MRS) is selective to groundwater. However, this distinctive feature has not been fully used in previous published studies for quantifying the drainable groundwater in hard rocks (i.e. the specific yield) and the short-term productivity of aquifer (i.e. the transmissivity). We present in this paper a comparison of MRS results (i.e. the water content and pore-size parameter) with both specific yield and transmissivity calculated from long duration pumping tests. We conducted our experiments in six sites located in different hard rock groups in Benin, thus providing a unique data set to assess the usefulness of MRS in hard rock aquifers. We found that the MRS water content is about twice the specific yield. We also found that the MRS pore-size parameter is well correlated with the specific yield. Thus we proposed two linear equations for calculating the specific yield from the MRS water content (with an uncertainty of about 10%) and from the pore-size parameter (with an uncertainty of about 20%). The later has the advantage of defining a so-named MRS cutoff time value for indentifying non-drainable MRS water content and thus low groundwater reserve. We eventually propose a nonlinear equation for calculating the specific yield using jointly the MRS water content and the pore-size parameters, but this approach has to be confirmed with further investigations. This study also confirmed that aquifer transmissivity can be estimated from MRS results with an uncertainty of about 70%. We conclude that MRS can be usefully applied for estimating aquifer specific yield and

Appraisal of hard rock for potential underground repositories of radioactive wastes

International Nuclear Information System (INIS)

Cook, N.G.W.

1977-10-01

The mechanical safety and stability of such an underground repository depends largely on the virgin state of stress in the rock, groundwater pressures, the strengths of the rocks, heating by the decay of the radioactive wastes, and the layout of the excavations and the disposition of waste cannisters within them. A large body of pertinent data exists in the literature, and each of these factors has been analyzed in the light of this information. The results indicate that there are no fundamental geological nor mechanical reasons why repositories capable of storing radioactive wastes should not be excavated at suitable sites in hard rock. However, specific tests to determine the mechanical and thermal properties of the rocks at a site would be needed to provide the data for the engineering design of a repository. Also, little experience exists of the effects on underground excavations of thermal loads, so that this aspect requires theoretical study and experimental validation. The depths of these potential repositories would lie in the range from 0.5 to 2.0 km below surface, depending upon the strength of the rock. Virgin states of stress have been measured at such depths which would retard the ingress of groundwater and obviate the incidence of faulting. A typical repository comprising three horizons each with a total area of 5 km 2 would have the capacity to store wastes with thermal output of 240 MW

Aespoe Hard Rock Laboratory Annual Report 1994

International Nuclear Information System (INIS)

1995-04-01

The Aespoe Hard Rock Laboratory is being constructed as part of the preparations for the deep geological repository of spent nuclear fuel in Sweden. The annual report 1994 contains an overview of the work conducted. Present work is focused on verification of pre-investigation methods and development of detailed investigation methodology which is applied during tunnel construction. Construction of the facility and detailed characterization of the bedrock are performed in parallel. Excavation of the main access tunnel was completed during 1994 and at the end of the year only minor excavation work remained. The last 400 m of the main tunnel, which has a total length of 3600 m, was excavated by a 5 m diameter boring machine. The tunnel reaches a depth of 450 m below ground. Preparations for the operating phase have started and detailed plans have been prepared for several experiments. Nine organizations, including SKB, from eight countries are now participating in the work at the laboratory. 50 refs, 28 figs

Aespoe Hard Rock Laboratory Annual Report 1994

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-04-01

The Aespoe Hard Rock Laboratory is being constructed as part of the preparations for the deep geological repository of spent nuclear fuel in Sweden. The annual report 1994 contains an overview of the work conducted. Present work is focused on verification of pre-investigation methods and development of detailed investigation methodology which is applied during tunnel construction. Construction of the facility and detailed characterization of the bedrock are performed in parallel. Excavation of the main access tunnel was completed during 1994 and at the end of the year only minor excavation work remained. The last 400 m of the main tunnel, which has a total length of 3600 m, was excavated by a 5 m diameter boring machine. The tunnel reaches a depth of 450 m below ground. Preparations for the operating phase have started and detailed plans have been prepared for several experiments. Nine organizations, including SKB, from eight countries are now participating in the work at the laboratory. 50 refs, 28 figs.

Joint ANDRA/Nirex/SKB zone of excavation disturbance experiment (ZEDEX) at the Aspo hard rock laboratory

International Nuclear Information System (INIS)

Hooper, A.J.; Olsson, O.

1995-01-01

The excavation of access shafts and tunnels and of the disposal areas of a waste repository will cause a disturbance in the surrounding rock mass with possible alterations to rock mass stability and hydraulic properties. For a number of disposal concepts this disturbance may be important for the operational and/or post-closure safety of the repository. Furthermore the disturbance may extend over time as a consequence of processes such as stress relaxation. The sponsors of ZEDEX, namely ANDRA, Nirex and SKB, are interested in developing the ability to produce reliable models of the disturbed zone that will develop around large cross-section excavations in fractured hard rock masses that are initially water saturated. Various models have been developed to calculate the important characteristics of the disturbed zone in such rock masses as a function of parameters related to the rock mass quality and the geometric description of the excavation. ZEDEX was initiated in the Aspo Hard Rock Laboratory in April 1994 with drilling and instrumentation of boreholes running alongside the planned extension of the spiral access ramp and a planned parallel experimental tunnel. ZEDEX has been designed to generate information for alternative methods of excavation. The extension to the spiral ramp is to be made by tunnel boring whereas the parallel experimental tunnel will be excavated in part by ''normal'' basting and in part by smooth blasting. The objective is to build confidence in the modelling of the disturbed zone to support the selection of excavation methods for repository construction. (authors). 3 figs

Assessment of fluoride contaminations in groundwater of hard rock aquifers in Madurai district, Tamil Nadu (India)

Science.gov (United States)

Thivya, C.; Chidambaram, S.; Rao, M. S.; Thilagavathi, R.; Prasanna, M. V.; Manikandan, S.

2017-05-01

The fluoride contamination in drinking water is already gone to the alarming level and it needs the immediate involvement and attention of all people to solve this problem. Fluoride problem is higher in hard rock terrains in worldwide and Madurai is such type of hard rock region. Totally 54 samples were collected from the Madurai district of Tamilnadu with respect to lithology. The samples collected were analysed for major cations and anions using standard procedures. The higher concentration of fluoride is noted in the Charnockite rock types of northern part of the study area. 20 % of samples are below 0.5 ppm and 6 % of samples are above 1.5 ppm exceeding the permissible limit. The affinity between the pH and fluoride ions in groundwater suggests that dissolution of fluoride bearing minerals in groundwater. The higher concentration of fluoride ions are observed in the lower EC concentration. The isotopic study suggests that fluoride is geogenic in nature. In factor scores, fluoride is noted in association with pH which indicates the dissolution process.

Aespoe Hard Rock Laboratory. Status Report. September - December 2010

International Nuclear Information System (INIS)

2011-04-01

The Aespoe Hard Rock Laboratory (HRL) constitutes an important part of SKB's work to design and construct a geological repository for spent nuclear fuel and to develop and test methods for characterisation of a suitable site. In September 2010, the plans for SKB's research and development of technique during the period 2011-2016 were presented in SKB's RDandD-Programme 2010 /SKB 2010a/. The information given in the RDandD-Programme related to Aespoe HRL is annually detailed in the Aespoe HRL Planning Report and the information valid for 2010 is given in /SKB 2010b/. This Aespoe HRL Status Report is a collection of the main achievements obtained during the period September to December 2010

Rocks and Other Hard Places: Tracing Ethical Thinking in Korean and English Dialog

Science.gov (United States)

Kim, Yong-Ho; Kellogg, David

2015-01-01

Researchers into moral education, and ethics educators too, often find themselves between a rock and a hard place. On the one hand, we wish to know what the child will do beyond the narrow range of communicative functions carried out in a classroom, and to do this, we employ purely hypothetical problems, that is, problems that from the child's…

Treatment and final disposal of nuclear waste. Aespoe hard rock laboratory

International Nuclear Information System (INIS)

1992-09-01

The scientific investigations within SBK's research programme are a part of the work of designing a deep repository and identifying and investigating a suitable site. A balanced appraisal of the facts, requirements and assessments presented in connection with the preparation of R and D-programme 86 led to the proposal to construct an underground research laboratory. This proposal was presented in the aforementioned research programme and was very positively recived by the reviewing bodies. In the autumn of 1986, SKB initiated the field work for the siting of an underground laboratory, the Aespoe hard rock laboratory, in the Simpevarp area in the municipality of Oskarshamn. At the end of 1988, SKB arrived at a decision in principle to site the facility on southern Aespoe about 2 km north of the Oskarshamn nuclear power station. After regulatory review, SKB ordered the excavation of the access tunnel to the Aespoe hard rock laboratory to commence in the autumn of 1990. In conjunction with the tunneling work, which has now (September 1992) reached a depth of more than 200 m, a large number of investigations have been carried out. This background report to SKB's RD and D-programme 92 is based on the previous and 89 /2/. The report provides a general background and presents goals, projects results obtained to date and future work. Compared to the previous background reports, more space is devoted here to experiment planning and the future demonstration programme. (au)

Quiet tunneling method in hard rock mass by cutting grooves and fracturing rock; Mizo wo hori, iwa wo wari, katai tonneru wo shizukani kussaku

Energy Technology Data Exchange (ETDEWEB)

Noma, T. [Fujita Corp., Tokyo (Japan)

1998-08-15

Where blasting cannot be applied due to large vibration and noise, adoption of mechanical tunneling is essential to tunneling of hard rock. In tunneling of hard rock, the existing of free surface is important. The free surface means a surface which does not restrict destruction on fracturing and it is important to form a continuous free surface efficiently and economically. The development of a new free surface forming engineering method is described. It requires no exclusive machines and all drilling works can be operated with general drill jumbo machine. In this new engineering method, the free surface is formed by continuous drilling of a single hole. Spinning anti-bend (SAB) rod is inserted into the existing drilled hole and a drill bit generates the free surface by contact with and blow the SAB rod. The procedure of the continuous drilling, an application example and the features of the procedure are described. This method has an ability to form a free surface more than 3.5m{sup 2}h even for rock bed wit compression strength more than 200MPa. 2 refs., 8 figs.

Surface-groundwater interactions in hard rocks in Sardon Catchment of western Spain: an integrated modeling approach

NARCIS (Netherlands)

Tanvir Hassan, S.M.; Lubczynski, M.; Niswonger, R.G.; Su, Zhongbo

2014-01-01

The structural and hydrological complexity of hard rock systems (HRSs) affects dynamics of surface–groundwater interactions. These complexities are not well described or understood by hydrogeologists because simplified analyses typically are used to study HRSs. A transient, integrated hydrologic

Aespoe Hard Rock Laboratory. Status Report. September - December 2010

Energy Technology Data Exchange (ETDEWEB)

2011-04-15

The Aespoe Hard Rock Laboratory (HRL) constitutes an important part of SKB's work to design and construct a geological repository for spent nuclear fuel and to develop and test methods for characterisation of a suitable site. In September 2010, the plans for SKB's research and development of technique during the period 2011-2016 were presented in SKB's RDandD-Programme 2010 /SKB 2010a/. The information given in the RDandD-Programme related to Aespoe HRL is annually detailed in the Aespoe HRL Planning Report and the information valid for 2010 is given in /SKB 2010b/. This Aespoe HRL Status Report is a collection of the main achievements obtained during the period September to December 2010

Abrasiveness and hardness of rocks of Cretaceous deposits of Chechen-Ingushetiya. Ob abrazivnosti i tverdosti gornykh porod melovykh otlozhenii Checheno-Ingushetii

Energy Technology Data Exchange (ETDEWEB)

Trofimenko, Yu.P.

1981-01-01

Presented are results of studies of the abrasiveness and hardness of core material taken from Upper Cretaceous deposits in the process of drilling deep boreholes in the areas of Chechen-Ingushetiya. Based on the studies it is established that the abrasiveness of rock is mainly influenced by the coarseness of the mineral grains in the rock, their mineralogical composition, and the composition of the cement. Given is a system of clasification of the investigated core material with respect to abrasiveness and hardness.

Release consequence analysis for a hypothetical geologic radioactive waste repository in hard rock

International Nuclear Information System (INIS)

1979-12-01

This report makes an evaluation of the long-term behaviour of the wastes placed in a hard rock repository. Impacts were analyzed for the seven reference fuel cycles of WG 7. The reference repository for this study is for granitic rock or gneiss as the host rock. The descriptions of waste packages and repository facilities used in this study represent only one of many possible designs based on the multiple barriers concept. The repository's size is based on a nuclear economy producing 100 gigawatts of electricity per year for 1 year. The objective of the modeling efforts presented in this study is to predict the rate of transport of radioactive contaminants from the repository through the geosphere to the biosphere and thus determine an estimate of the potential dose to humans so that the release consequence impacts of the various fuel cycles can be compared. Currently available hydrologic, leach, transport, and dose models were used in this study

Groundwater-quality data in the Santa Cruz, San Gabriel, and Peninsular Ranges Hard Rock Aquifers study unit, 2011-2012: results from the California GAMA program

Science.gov (United States)

Davis, Tracy A.; Shelton, Jennifer L.

2014-01-01

Groundwater quality in the 2,400-square-mile Santa Cruz, San Gabriel, and Peninsular Ranges Hard Rock Aquifers (Hard Rock) study unit was investigated by the U.S. Geological Survey (USGS) from March 2011 through March 2012, as part of the California State Water Resources Control Board (SWRCB) Groundwater Ambient Monitoring and Assessment (GAMA) Program’s Priority Basin Project (PBP). The GAMA-PBP was developed in response to the California Groundwater Quality Monitoring Act of 2001 and is being conducted in collaboration with the SWRCB and Lawrence Livermore National Laboratory (LLNL). The Hard Rock study unit was the 35th study unit to be sampled as part of the GAMA-PBP.

Aespoe hard rock laboratory. Field investigation methodology and instruments used in the preinvestigation phase, 1986-1990

International Nuclear Information System (INIS)

Almen, K.E.; Zellman, O.

1991-12-01

The Aespoe hard rock laboratory project started in 1986. The pre-investigation phase, 1986-1990, involved extensive field measurements from the surface as well as from boreholes, aimed at characterizing the rock formation with regard to geology, geohydrology, hydrochemistry and rock mechanics. The field investigation methodology used in the project was based on experience from and developments during the previous SKB study site investigation programme. However, in some respects the techniques were changed or modified. Major changes have been possible due to a new drilling technique, telescope-type drilling. This report describes the logistics of the investigation programme, characterized to a large extent by multi-purpose planning and performance of the activities in order to optimize the use of available resources; time, personnel and equipment. Preliminary hydraulic testing and groundwater sampling were conducted during the drilling of each borehole. When the drilling was completed an extensive set of singlehole investigations were carried out: geophysical logging, borehole radar, hydraulic tests of different kinds, water sampling and rock stress measurements. Multipackers were installed in the boreholes as soon as possible after the borehole investigations. The system enables monitoring of groundwater pressure, water sampling and groundwater flow measurements to be performed by means of dilution tests and tracer injection. Boreholes with such equipment were used as observation holes during interference pumping tests and long term hydraulic and tracer tests. The monitoring programme will continue during the subsequent phases of construction and operation of the Aespoe hard rock laboratory. (83 refs., 94 figs.) (au)

Influence of different geological structures on stress–strain state of hard rock mass

Science.gov (United States)

Kuznetzov, NN; Fedotova, YuV

2018-03-01

The results of numerical simulation of stress–strain state in a hard rock mass area with the complex geological structures are presented. The variants of the stress value change are considered depending on the boundary conditions and physical properties of the model blocks. Furthermore, the possibility of in-situ stress formation under the influence of energy coming from the deeper Earth’s layers is demonstrated in terms of the Khibiny Massif.

A Coupled Thermo-Hydro-Mechanical Model of Jointed Hard Rock for Compressed Air Energy Storage

Directory of Open Access Journals (Sweden)

Xiaoying Zhuang

2014-01-01

Full Text Available Renewable energy resources such as wind and solar are intermittent, which causes instability when being connected to utility grid of electricity. Compressed air energy storage (CAES provides an economic and technical viable solution to this problem by utilizing subsurface rock cavern to store the electricity generated by renewable energy in the form of compressed air. Though CAES has been used for over three decades, it is only restricted to salt rock or aquifers for air tightness reason. In this paper, the technical feasibility of utilizing hard rock for CAES is investigated by using a coupled thermo-hydro-mechanical (THM modelling of nonisothermal gas flow. Governing equations are derived from the rules of energy balance, mass balance, and static equilibrium. Cyclic volumetric mass source and heat source models are applied to simulate the gas injection and production. Evaluation is carried out for intact rock and rock with discrete crack, respectively. In both cases, the heat and pressure losses using air mass control and supplementary air injection are compared.

Assessment of site-scale hydrogeological modelling possibilities in crystalline hard rock for safety appraisal

Energy Technology Data Exchange (ETDEWEB)

Geier, J. [Cleanwater Hardrock Consulting, Corvallis, OR (United States); Luukkonen, A.

2012-09-15

This review describes the state-of-the-art in hydrogeological modelling for safety-case studies related to spent-fuel repositories in crystalline hard rock, focusing on issues of relevance for the KBS-3 disposal concept in Nordic environments. The review includes a survey of model capabilities and assumptions regarding groundwater flow processes, geological and excavation-related features, and boundary conditions for temperate, periglacial, and glacial climates. Modelling approaches are compared for research sites including the Stripa mine (Sweden), the Grimsel Test Site (Switzerland), the Whiteshell Underground Research Laboratory (Canada), the Aspo Hard Rock Laboratory and Simpevarp-Laxemar site (Sweden), the Forsmark site (Sweden), the Waste Isolation Pilot Plant site (USA), and Olkiluoto (Finland). Current hydrogeological models allow realistic representations, but are limited by availability of data to constrain their properties. Examples of calibrations of stochastic representations of heterogeneity are still scarce. Integrated models that couple flow and non-reactive transport are now well established, particularly those based on continuum representations. Models that include reactive transport are still mainly in the realm of research tools. Thus far, no single software tool allows fully coupled treatment of all relevant thermal, hydraulic, mechanical, and chemical transport processes in the bedrock, together with climate-related physical processes at the ground surface, and with explicit treatment of bedrock heterogeneity. Hence practical applications require combinations of models based on different simplifications. Key improvements can be expected in treatment of the unsaturated zone, simulation of heterogeneous infiltration at the surface, and hydromechanical coupling. Significant advances have already been made in the amounts and types of data that can be used in site-scale models, including large datasets to define topography and other surface

A study on variation in dissolved silica concentration in groundwater of hard rock aquifers in Southeast coast of India

International Nuclear Information System (INIS)

Pradeep, K; Nepolian, M; Anandhan, P; Chandran; Kaviyarasan, R; Chidambaram, S; Prasanna, M V

2016-01-01

Ground water of hard rock aquifers due to its lesser permeability results in the increased residence time, which leads to the higher concentration of ions. Hence in order to understand the hydro-geochemistry of the groundwater of a hard rock aquifer in India, 23 groundwater samples were collected from different locations of the study area and subjected to analysis of major cations and anions. The results of silica showed different range of concentration and was plotted in different groups. In order to understand the reason for this variation, different techniques like Thermodynamics, Statistics and GIS were adopted and it was inferred that the concentration was mainly governed by lithology and land use pattern of the study area. (paper)

Importance of creep failure of hard rock in the near field of a nuclear-waste repository

International Nuclear Information System (INIS)

Blacic, J.D.

1981-01-01

Potential damage resulting from slow creep deformation intuitively seems unlikely for a high-level nuclear waste repository excavated in hard rock. However, recent experimental and modeling results indicate that the processes of time-dependent microcracking and water-induced stress corrosion can lead to significant reductions in strength and alteration of other key rock properties in the near-field region of a repository. We review the small data base supporting these conclusions and stress the need for an extensive laboratory program to obtain the new data that will be required for design of a repository

Importance of creep failure of hard rock in the near field of a nuclear waste repository

Energy Technology Data Exchange (ETDEWEB)

Blacic, J D [Los Alamos National Laboratory, NM, (USA)

1982-12-31

Potential damage resulting from slow creep deformation intuitively seems unlikely for a high-level nuclear waste repository excavated in hard rock. However, recent experimental and modeling results indicate that the processes of time-dependent microcracking and water-induced stress corrosion can lead to significant reductions in strength and alteration of other key rock properties in the near-field region of a repository. We review the small data base supporting these conclusions and stress the need for an extensive laboratory program to obtain the new data that will be required for design of a repository.

Aespoe hard rock laboratory. Annual report 2000

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-06-01

The Aespoe Hard Rock Laboratory constitutes an important component of SKB's work to design, construct, and implement a deep geological repository for spent nuclear fuel and to develop and test methods for characterisation of selected repository sites. The retention effect of the rock has been studied by tracer tests in the Tracer Retention Understanding Experiments (TRUE) and the TRUE Block Scale (TRUE BS). These tests are supplemented by the new Long Term Diffusion Experiment (LTDE). During year 2000 the field experiments of TRUE BS (50 m scale) were completed and preparations made for the LTDE (migration through a fracture wall and into the rock), including boring of approximately 10 m deep hole with 300 mm diameter. Laboratory investigations have difficulties in simulating natural conditions and need supplementary field studies to support validation exercises. A special borehole probe, CHEMLAB, has therefore been designed for different kinds of validation experiments where data can be obtained representative for the in-situ properties of groundwater at repository depth. During 2000 migration experiments were made with actinides (Am, Np and Pu) in CHEMLAB 2, the simplified supplement to CHEMLAB 1. Colloids of nuclides as well as of bentonite might affect the migration of released radionuclides and a separate project was planned during 2000 to assess the existence, stability and mobility of colloids. The development of numerical modelling tools continues with the general objective to improve the numerical models in terms of flow and transport and to update the site-scale and laboratory scale models for the Aespoe HRL. The Matrix Fluid Chemistry project aims at determining the origin and age of matrix fluids and the experiment has been designed to sample matrix fluids from predetermined, isolated borehole sections by specialised equipment. The Aespoe HRL also has the task to demonstrate and perform full scale tests of the function of different components of

Identification of a Suitable 3D Printing Material for Mimicking Brittle and Hard Rocks and Its Brittleness Enhancements

Science.gov (United States)

Zhou, T.; Zhu, J. B.

2018-03-01

Three-dimensional printing (3DP) is a computer-controlled additive manufacturing technique which is able to repeatedly and accurately fabricate objects with complicated geometry and internal structures. After 30 years of fast development, 3DP has become a mainstream manufacturing process in various fields. This study focuses on identifying the most suitable 3DP material from five targeted available 3DP materials, i.e. ceramics, gypsum, PMMA (poly(methyl methacrylate)), SR20 (acrylic copolymer) and resin (Accura® 60), to simulate brittle and hard rocks. Firstly, uniaxial compression tests were performed to determine the mechanical properties and failure patterns of the 3DP samples fabricated by those five materials. Experimental results indicate that among current 3DP techniques, the resin produced via stereolithography (SLA) is the most suitable 3DP material for mimicking brittle and hard rocks, although its brittleness needs to be improved. Subsequently, three methods including freezing, incorporation of internal macro-crack and addition of micro-defects were adopted to enhance the brittleness of the 3DP resin, followed by uniaxial compression tests on the treated samples. Experimental results reveal that 3DP resin samples with the suggested treatments exhibited brittle properties and behaved similarly to natural rocks. Finally, some prospective improvements which can be used to facilitate the application of 3DP techniques to rock mechanics were also discussed. The findings of this paper could contribute to promoting the application of 3DP technique in rock mechanics.

Disc cutter wear and rock texture in hard rock TBM tunneling

International Nuclear Information System (INIS)

Koizumi, Yu; Tsusaka, Kimikazu; Tanimoto, Chikaosa; Nakagawa, Shigeo; Fujita, Naoya

2008-01-01

Disc cutter wear in TBM tunneling is caused by initial fragmentation of a solid rock face (the primary fragmentation) and fragmentation of residual rock pieces between a cutterhead and the face (the secondary fragmentation). In two projects through sedimentary and granitic rocks, the authors investigated the relationships between the rate of cutter wear caused by the primary fragmentation, point load index and the grain size and contents of abrasive minerals. As a result, it was found that the tensile strength and the mineral contents of rocks significantly influenced the cutter wear in both projects and thus it is necessary to take into account of rock type. (author)

Swedish Hard Rock Laboratory first evaluation of preinvestigations 1986-87 and target area characterization

International Nuclear Information System (INIS)

Gustafson, G.; Stanfors, R.; Wikberg, P.

1988-06-01

SKB plans to site an underground research laboratory in the Simpevarp area. A regional survey started in 1986 and an extensive programme for geology, geohydrology and hydrochemistry was carried through. This report gives an evaluation of all available data gathered from the start of the project up to the drilling of core boreholes in some target areas in the autumn of 1987. A descriptive geological-tectonic model on a regional scale is presented that is intended to constitute a basis for the hydrogeological modelling work. Preliminary rock mass descriptions are also presented on a more detailed scale for some minor parts of the area. It is recommended that the island Aespoe is the principal target area for the continued work on the Swedish Hard Rock Laboratory. (orig.)

Aespoe hard rock laboratory. Annual report 2000

International Nuclear Information System (INIS)

2001-06-01

The Aespoe Hard Rock Laboratory constitutes an important component of SKB's work to design, construct, and implement a deep geological repository for spent nuclear fuel and to develop and test methods for characterisation of selected repository sites. The retention effect of the rock has been studied by tracer tests in the Tracer Retention Understanding Experiments (TRUE) and the TRUE Block Scale (TRUE BS). These tests are supplemented by the new Long Term Diffusion Experiment (LTDE). During year 2000 the field experiments of TRUE BS (50 m scale) were completed and preparations made for the LTDE (migration through a fracture wall and into the rock), including boring of approximately 10 m deep hole with 300 mm diameter. Laboratory investigations have difficulties in simulating natural conditions and need supplementary field studies to support validation exercises. A special borehole probe, CHEMLAB, has therefore been designed for different kinds of validation experiments where data can be obtained representative for the in-situ properties of groundwater at repository depth. During 2000 migration experiments were made with actinides (Am, Np and Pu) in CHEMLAB 2, the simplified supplement to CHEMLAB 1. Colloids of nuclides as well as of bentonite might affect the migration of released radionuclides and a separate project was planned during 2000 to assess the existence, stability and mobility of colloids. The development of numerical modelling tools continues with the general objective to improve the numerical models in terms of flow and transport and to update the site-scale and laboratory scale models for the Aespoe HRL. The Matrix Fluid Chemistry project aims at determining the origin and age of matrix fluids and the experiment has been designed to sample matrix fluids from predetermined, isolated borehole sections by specialised equipment. The Aespoe HRL also has the task to demonstrate and perform full scale tests of the function of different components of the

Experience gained from the site characterisation strategy used at the Aespoe hard rock laboratory

Energy Technology Data Exchange (ETDEWEB)

Baeckblom, G. [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)

1998-09-01

The Aespoe Hard Rock Laboratory is a `dress-rehearsal` facility to test, develop and demonstrate technology and models prior to applications at the actual deep repository site in Sweden. Site characterisation methodology has for more than a decade been a main issue at the Aespoe Hard Rock Laboratory (HRL). At the start of site investigations in 1987 the following strategy was adopted: Comprehensive surface and surface-based investigations; Multi-disciplinary data collection in batches; Staged integrated evaluations on selected key issues closely tied to existing knowledge of the geology of the site; Iterative modelling on several geometrical scales based on existing (scarce) data; `Predictive approach` to model updating. During the construction phase of the Aespoe HRL (1990 - 1995), a multitude of data was collected to test and to increase the details of the models made prior to construction. Several things have been learned regarding the appropriateness of the adopted approach to site characterisation. These findings concern e.g. data collection methods from surface and underground, construction/test-integration, choice of useful and feasible model concepts, data flow and document management. The acquired understanding, knowledge, skill and know-how are very valuable for planning useful and feasible site characterisation for the deep repository in Sweden

Experience gained from the site characterisation strategy used at the Aespoe hard rock laboratory

International Nuclear Information System (INIS)

Baeckblom, G.

1998-01-01

The Aespoe Hard Rock Laboratory is a 'dress-rehearsal' facility to test, develop and demonstrate technology and models prior to applications at the actual deep repository site in Sweden. Site characterisation methodology has for more than a decade been a main issue at the Aespoe Hard Rock Laboratory (HRL). At the start of site investigations in 1987 the following strategy was adopted: Comprehensive surface and surface-based investigations; Multi-disciplinary data collection in batches; Staged integrated evaluations on selected key issues closely tied to existing knowledge of the geology of the site; Iterative modelling on several geometrical scales based on existing (scarce) data; 'Predictive approach' to model updating. During the construction phase of the Aespoe HRL (1990 - 1995), a multitude of data was collected to test and to increase the details of the models made prior to construction. Several things have been learned regarding the appropriateness of the adopted approach to site characterisation. These findings concern e.g. data collection methods from surface and underground, construction/test-integration, choice of useful and feasible model concepts, data flow and document management. The acquired understanding, knowledge, skill and know-how are very valuable for planning useful and feasible site characterisation for the deep repository in Sweden

Application of deep hole blasting to shaft sinking in a hard rock-type uranium mine in south china

International Nuclear Information System (INIS)

Feng Haisheng; Zeng Lingguo; Ding Dexin

2009-01-01

The shaft for backfilling in the 43 exploratory line on the 200 m level in the Mianhuakang mining area in a hard rock uranium mine in South China could not be excavated by using conventional shaft sinking methode since it was near the fault zone and the rock around it was broken and water-bearing. Therefore, the shaft was excavated by using deep hole blasting. This paper presented the design for the blasting and the construction. (authors)

A study on the U speciation in groundwater of a hard rock aquifer in South India

International Nuclear Information System (INIS)

Thivya, C.; Chidambaram, S.; Thilagavathi, R.; Nepolian, M.; Adithya, V.S.; Tirumalesh, K.; Prasanna, M.V.

2015-01-01

Speciation of uranium indicates the contribution of this ion into different species. An attempt has been made to study the spatial and temporal variations of U speciation in the hard rock aquifer of South India. The major rock types have granulite facies with high grade metamorphic rocks and younger intrusive. It also comprises of Fissile hornblende biotite gneiss, Charnockite, Quartzite, Granite and Flood Plain Alluvium. A total of 108 samples were collected from the handpumps of the study area for two seasons (Pre monsoon and South West monsoon). The groundwater samples were analysed for U and other ions like Ca 2+ , Mg 2+ , Na + and K + , HCO 3 - , Cl - , SO 4 2- , PO 4 3- , NO 3 - , F - , H 4 SiO 4 , pH, EC and TDS using standard procedures

Rock disposal problems identified

Energy Technology Data Exchange (ETDEWEB)

Knox, R

1978-06-01

Mathematical models are the only way of examining the return of radioactivity from nuclear waste to the environment over long periods of time. Work in Britain has helped identify areas where more basic data is required, but initial results look very promising for final disposal of high level waste in hard rock repositories. A report by the National Radiological Protection Board of a recent study, is examined.

Aespoe Hard Rock Laboratory. The TASS-tunnel. Geological mapping

Energy Technology Data Exchange (ETDEWEB)

Hardenby, Carljohan (Vattenfall Power Consultant AB (Sweden)); Sigurdsson, Oskar (HAskGeokonsult AB (Sweden))

2010-12-15

The project entitled 'Sealing of tunnel at great depth' (Fintaetning av tunnel paa stort djup) needed a new tunnel in an area as undisturbed as possible and with cross-cutting water-bearing structures. The new tunnel, which was given the name TASS, was excavated on the -450 m level of SKB's Aespoe Hard Rock Laboratory (Aespoe HRL). The length of the tunnel is approximately 80 m and the theoretical tunnel area 19 m2. As is the case with all the other tunnels of the Aespoe HRL, the new tunnel has been geologically mapped. In addition, laser scanning combined with digital photography has been carried out. The tunnel was also used to test various types of explosives, borehole layouts and drilling techniques. The geological mapping of tunnel floor, walls and roof took place on four major occasions when a halt was made in tunnel excavation to allow for various tests. Before the mapping started on these occasions, laser scanning took place. The tunnel faces were mapped after each round (drilling, blasting and unloading). The present report describes the geological features of the tunnel and briefly how the laser scanning was performed. Water-bearing structures have been compared to similar structures in the neighbouring tunnels. The rock type names used here follow the old established Aespoe HRL nomenclature. Narrow (<0.1 m wide) dykes are normally mapped as fracture fillings. The dominating rock type is Aespoe diorite, which constitutes some 90 % of the rock mass. It is mostly mapped as fresh rock. . Minor constituents of the rock mass are fine-grained granite, hybrid rock, pegmatite, quartz veins/lenses and undifferentiated mafic rock. The mapping of fractures and deformation zones considers a number of parameters such as number of fractures, open/healed, width, length, description of fracture surfaces (roughness, planarity, etc), fracture filling, alteration and water. The deformation zones are discriminated into two main categories (&apos

Aespoe Hard Rock Laboratory. The TASS-tunnel. Geological mapping

International Nuclear Information System (INIS)

Hardenby, Carljohan; Sigurdsson, Oskar

2010-12-01

The project entitled 'Sealing of tunnel at great depth' (Fintaetning av tunnel paa stort djup) needed a new tunnel in an area as undisturbed as possible and with cross-cutting water-bearing structures. The new tunnel, which was given the name TASS, was excavated on the -450 m level of SKB's Aespoe Hard Rock Laboratory (Aespoe HRL). The length of the tunnel is approximately 80 m and the theoretical tunnel area 19 m 2 . As is the case with all the other tunnels of the Aespoe HRL, the new tunnel has been geologically mapped. In addition, laser scanning combined with digital photography has been carried out. The tunnel was also used to test various types of explosives, borehole layouts and drilling techniques. The geological mapping of tunnel floor, walls and roof took place on four major occasions when a halt was made in tunnel excavation to allow for various tests. Before the mapping started on these occasions, laser scanning took place. The tunnel faces were mapped after each round (drilling, blasting and unloading). The present report describes the geological features of the tunnel and briefly how the laser scanning was performed. Water-bearing structures have been compared to similar structures in the neighbouring tunnels. The rock type names used here follow the old established Aespoe HRL nomenclature. Narrow (<0.1 m wide) dykes are normally mapped as fracture fillings. The dominating rock type is Aespoe diorite, which constitutes some 90 % of the rock mass. It is mostly mapped as fresh rock. . Minor constituents of the rock mass are fine-grained granite, hybrid rock, pegmatite, quartz veins/lenses and undifferentiated mafic rock. The mapping of fractures and deformation zones considers a number of parameters such as number of fractures, open/healed, width, length, description of fracture surfaces (roughness, planarity, etc), fracture filling, alteration and water. The deformation zones are discriminated into two main categories ('increased fracturing' and

Hydrogeophysics and remote sensing for the design of hydrogeological conceptual models in hard rocks - Sardón catchment (Spain)

Science.gov (United States)

Francés, Alain P.; Lubczynski, Maciek W.; Roy, Jean; Santos, Fernando A. M.; Mahmoudzadeh Ardekani, Mohammad R.

2014-11-01

Hard rock aquifers are highly heterogeneous and hydrogeologically complex. To contribute to the design of hydrogeological conceptual models of hard rock aquifers, we propose a multi-techniques methodology based on a downward approach that combines remote sensing (RS), non-invasive hydrogeophysics and hydrogeological field data acquisition. The proposed methodology is particularly suitable for data scarce areas. It was applied in the pilot research area of Sardón catchment (80 km2) located west of Salamanca (Spain). The area was selected because of hard-rock hydrogeology, semi-arid climate and scarcity of groundwater resources. The proposed methodology consisted of three main steps. First, we detected the main hydrogeological features at the catchment scale by processing: (i) a high resolution digital terrain model to map lineaments and to outline fault zones; and (ii) high-resolution, multispectral satellite QuickBird and WorldView-2 images to map the outcropping granite. Second, we characterized at the local scale the hydrogeological features identified at step one with: i) ground penetrating radar (GPR) to assess groundwater table depth complementing the available monitoring network data; ii) 2D electric resistivity tomography (ERT) and frequency domain electromagnetic (FDEM) to retrieve the hydrostratigraphy along selected survey transects; iii) magnetic resonance soundings (MRS) to retrieve the hydrostratigraphy and aquifer parameters at the selected survey sites. In the third step, we drilled 5 boreholes (25 to 48 m deep) and performed slug tests to verify the hydrogeophysical interpretation and to calibrate the MRS parameters. Finally, we compiled and integrated all acquired data to define the geometry and parameters of the Sardón aquifer at the catchment scale. In line with a general conceptual model of hard rock aquifers, we identified two main hydrostratigraphic layers: a saprolite layer and a fissured layer. Both layers were intersected and drained by

Review on the prevailing methods for the prediction of potential rock burst / rock spalling in tunnels

OpenAIRE

Panthi, Krishna Kanta

2017-01-01

Rock burst / rock spalling is among the prevailing stability challenges, which can be met while tunneling through hard rock mass. Especially, this is very relevant for the mountainous country like Norway where hard rock is dominating and many road, railway and hydropower tunnels have to be aligned deep into the mountain with steep valley slope topography. Tunnels passing beneath deep rock cover (overburden), in general, are subjected to high in-situ stresses. If the rock mass is relatively un...

Friction of hard surfaces and its application in earthquakes and rock slope stability

Science.gov (United States)

Sinha, Nitish; Singh, Arun K.; Singh, Trilok N.

2018-05-01

In this article, we discuss the friction models for hard surfaces and their applications in earth sciences. The rate and state friction (RSF) model, which is basically modified form of the classical Amontons-Coulomb friction laws, is widely used for explaining the crustal earthquakes and the rock slope failures. Yet the RSF model has further been modified by considering the role of temperature at the sliding interface known as the rate, state and temperature friction (RSTF) model. Further, if the pore pressure is also taken into account then it is stated as the rate, state, temperature and pore pressure friction (RSTPF) model. All the RSF models predict a critical stiffness as well as a critical velocity at which sliding behavior becomes stable/unstable. The friction models are also used for predicting time of failure of the rock mass on an inclined plane. Finally, the limitation and possibilities of the proposed friction models are also highlighted.

Direct fault dating trials at the Aespoe Hard Rock Laboratory

International Nuclear Information System (INIS)

Maddock, R.H.; Hailwood, E.A.

1993-10-01

Over seventy rock samples were collected from fault and fracture zones in the Aespoe Hard Rock Laboratory tunnel for a study of direct fault dating techniques. Following microstructural and mineralogical analysis, isotopic, palaeomagnetic and electron spin resonance (ESR) methods were employed in an attempt to determine the age of the most recent movements on the sampled faults. The larger fracture zones contain faultrock assemblages and microstructures which are consistent with a prolonged and polyphase movement history, although the cumulative displacements involved formation of fault gouge cemented by authigenic 'illite'. Dating studies were targeted particularly at the gouge but also at older fault rock and vein phases. ESR dating of quartz graines, separated from gouge from fracture zones NE-4 and NE-3, strongly indicates that the ESR signals have not been reset by fault movements for a minimum time period of several hundred thousand to one million years. Palaeomagnetic dating of gouge from fracture zone NE-4 shows that a stable component of magnetisation overlaps both Precambrian and Permo-Triassic parts of the apparent polar wander curve. The younger age of magnetisation is preferred on geological grounds and by comparison with the isotopic dating results. The magnetisation may correspond to a diagenetic event following fault movement. Palaeomagnetic ages determined on countryrock and epidote vein samples are largely consistent with independent age constraints. K-Ar dating of clay fractions (<2 to <0.05μm) separated from gouge from four faults, including fracture zones NE-4 and NE-3, gave model ages in the range 706-301Ma. Accounting for the effects of contamination by potassium-bearing porphyroclasts, it is likely that authigenic 'illite' was formed at least 250 million years ago, after the most recent significant fault movements. 100 refs., 60 figs., 26 tabs

Proceedings of the fifth international groundwater conference on the assessment and management of groundwater resources in hard rock systems with special reference to basaltic terrain

International Nuclear Information System (INIS)

Thangarajan, M.; Mayilswami, C.; Kulkarni, P.S.; Singh, V.P.

2012-01-01

Groundwater resources in hard rock regions with limited renewable potential have to be managed judiciously to ensure adequate supplies of dependable quantity and quality. It is a natural resource with economic, strategic and environmental value, which is under stress both due to changing climatic and anthropogenic factors. Therefore the management strategies need to be aimed at sustenance of this limited resource. In India, and also elsewhere in the world major parts of the semi-arid regions are characterized by hard rocks and it is of vital importance to understand the nature of the aquifer systems and its current stress conditions. Though the achievements through scientific development in exploration and exploitation are commendable, it has adversely affected the hard rock aquifer system, both in terms of quantity and quality; which is of major concern today. In order to reverse the situation, better management strategy of groundwater resources needs to be devised for prevention of further degradation of quality and meeting out the future demand of quantity. This necessitates: understanding the flow mechanism, evaluating the potential and evolving optimal utilization schemes, and assessing and monitoring quality in the changing scenario of anthropogenically induced agricultural, urban, industrial and climatic change. The groundwater flow mechanism through fractures in hard rocks is yet to be fully understood in terms of fracture geometry and its relation to groundwater flow. The characterization of flow geometry in basaltic aquifer is yet to be fully explored. Groundwater pollution due to anthropogenic factors is very slow process with long-term impacts on carbon cycle and global climatic change on one hand and quality on the other. It is generally recognized that the prevention of groundwater pollution is cheaper than its remedial measures in the long run. Furthermore, because of the nature of groundwater flow and the complexity and management uncertainty of

Seismic activity and environment protection in rock burst areas

International Nuclear Information System (INIS)

Travnicek, L.; Holecko, J.; Knotek, S.

1993-01-01

The significance is pointed out of seismic activity caused by mining activities in rock burst areas of the Ostrava-Karvinna district. The need is emphasized of the monitoring of the seismic activity at the Czech-Poland border as needed by the Two-party international committee for exploitation of coal supplies on the common border. The adverse effect of rock burst on the surface is documented by examples provided by the Polish party. The technique is described of investigating the DPB seismic polygon, allowing to evaluate the adverse impact of rock burst on the environment. (author) 1 fig., 8 refs

Theoretical analysis and design of hydro-hammer with a jet actuator: An engineering application to improve the penetration rate of directional well drilling in hard rock formations.

Science.gov (United States)

He, Jiang-Fu; Liang, Yun-Pei; Li, Li-Jia; Luo, Yong-Jiang

2018-01-01

Rapid horizontal directional well drilling in hard or fractured formations requires efficient drilling technology. The penetration rate of conventional hard rock drilling technology in horizontal directional well excavations is relatively low, resulting in multiple overgrinding of drill cuttings in bottom boreholes. Conventional drilling techniques with reamer or diamond drill bit face difficulties due to the long construction periods, low penetration rates, and high engineering costs in the directional well drilling of hard rock. To improve the impact energy and penetration rate of directional well drilling in hard formations, a new drilling system with a percussive and rotary drilling technology has been proposed, and a hydro-hammer with a jet actuator has also been theoretically designed on the basis of the impulse hydro-turbine pressure model. In addition, the performance parameters of the hydro-hammer with a jet actuator have been numerically and experimentally analyzed, and the influence of impact stroke and pumped flow rate on the motion velocity and impact energy of the hydro-hammer has been obtained. Moreover, the designed hydro-hammer with a jet actuator has been applied to hard rock drilling in a trenchless drilling program. The motion velocity of the hydro-hammer ranges from 1.2 m/s to 3.19 m/s with diverse flow rates and impact strokes, and the motion frequency ranges from 10 Hz to 22 Hz. Moreover, the maximum impact energy of the hydro-hammer is 407 J, and the pumped flow rate is 2.3 m3/min. Thus, the average penetration rate of the optimized hydro-hammer improves by over 30% compared to conventional directional drilling in hard rock formations.

Attenuation characteristics of seismic motion based on earthquake observation records. Identification of damping factor at hard rock sites and its influences on ground stability evaluation

International Nuclear Information System (INIS)

Sato, Hiroaki; Kanatani, Mamoru; Ohtori, Yasuki

2005-01-01

In this report, we examined validity of currently available ground stability evaluation method by applying commonly used damping factor which was invariant for frequency. First, we conducted a survey of the actual conditions of damping factors, which were used in ground stability evaluation, on 10 existing nuclear power plants. As a result, we found that damping factor of 0.03(3%) was used in of 80 percent investigated plants. Next, a spectral inversion method using very fast simulated annealing was proposed for identifying damping factor and its lower limit. Here, the lower limit of damping factor means intrinsic damping factor. The developed inversion method was applied to borehole array data recorded at hard rock ground. From the inversion, it was found that intrinsic damping factor of hard rock ground distributed between about 0.03(3%) and 0.06(3%) at a depth of less than 100m, and between about 0.003(0.3%) and 0.01(1%) at a depth of more than 100m. Furthermore, we indicated that scattering damping factor with in a depth of less than 100m was in proportion to the almost -1.0 power of the frequency, and the factor in a depth of more than 100m had a peak in a frequency range from about 1.0 to 5.0 Hz. Therefore, it was recognized that commonly used damping of 0.03(3%) expressed intrinsic damping factor of shallower hard rock ground. Finally, we estimated the influences of damping factor on ground stability evaluation by 2D dynamic FEM analyses of hard rock foundation ground considering 8 slipping lines using 6 combinations of damping factor. It was demonstrated that the variation of damping factor was not so decisive on the results of ground stability evaluation. This suggests present ground stability evaluation method by applying commonly used damping factor is reasonable for hard rock sites. (author)

3D laser scanning techniques applying to tunnel documentation and geological mapping at Aespoe hard rock laboratory, Sweden

International Nuclear Information System (INIS)

Feng, Q.; Wang, G.; Roeshoff, K.

2008-01-01

3D terrestrial laser scanning is nowadays one of the most attractive methods to applying for 3D mapping and documentation of rock faces and tunnels, and shows the most potential to improve the data quality and provide some good solutions in rock engineering projects. In this paper, the state-of-the-art methods are described for different possibility to tunnel documentation and geological mapping based on 3D laser scanning data. Some results are presented from the case study performed at the Hard Rock Laboratory, Aespoe run by SKB, Swedish Nuclear Fuel and Waste Management Co. Comparing to traditional methods, 3D laser scanning techniques can not only provide us with a rapid and 3D digital way for tunnel documentation, but also create a potential chance to achieve high quality data, which might be beneficial to different rock engineering project procedures, including field data acquisition, data processing, data retrieving and management, and also modeling and design. (authors)

Enculturating environments: rock art and the archaeology of interior south-central California

OpenAIRE

Sturt, Fraser C.; Robinson, David; Bernard, Julienne

2010-01-01

The disarticulation of rock art from the archaeological record and its changing environment remains a primary obstacle facing many rock art researchers across the globe, but particularly in the American Far West, and California specifically (Robinson & Sturt 2009). A schism, so to speak, exists between the archaeological record and rock art as well as 'dirt' archaeologists and rock art specialists. This is because, in California, and particularly in the rock art rich area of south-central...

Hard Rock Café Colombia, ejemplo de una franquicia exitosa

Directory of Open Access Journals (Sweden)

Julian Besedicheck Prieto

2008-11-01

Full Text Available La incursión y expansión de restaurantes y cadenas hoteleras en Colombia ha generado distintas oportunidades de negocio; por lo tanto, es importante analizar desde distintas ópticas este fenómeno, porque éste puede ser una solución empresarial para muchas compañías, inversionistas y personas. Con el auge del comercio internacional y la apertura económica en Colombia han ingresado un gran número de empresas al mercado nacional bajo distintas figuras, dentro de éstas se encuentra la franquicia, que ha permitido el ingreso de compañías de la industria de restaurantes como McDonald’s, Burger King, TGI Fridays, entre otras.En el siguiente artículo se observará una breve muestra del funcionamiento y desarrollo del restaurante Hard Rock Café Bogotá, desde su primer contacto con la casa matriz hasta su apertura y sus eventos durante los últimos 6 años.

Hard Rock Café Colombia, ejemplo de una franquicia exitosa

Directory of Open Access Journals (Sweden)

Julián Besedicheck Prieto

2008-11-01

Full Text Available La incursión y expansión de restaurantes y cadenas hoteleras en Colombia ha generado distintas oportunidades de negocio; por lo tanto, es importante analizar desde distintas ópticas este fenómeno, porque éste puede ser una solución empresarial para muchas compañías, inversionistas y personas. Con el auge del comercio internacional y la apertura económica en Colombia han ingresado un gran número de empresas al mercado nacional bajo distintas figuras, dentro de éstas se encuentra la franquicia, que ha permitido el ingreso de compañías de la industria de restaurantes como McDonald’s, Burger King, TGI Fridays, entre otras. En el siguiente artículo se observará una breve muestra del funcionamiento y desarrollo del restaurante Hard Rock Café Bogotá, desde su primer contacto con la casa matriz hasta su apertura y sus eventos durante los últimos 6 años.

Develop guidelines for the design of pillar systems for shallow and intermediate depth, tabular, hard rock mines and provide a methodology for assessing hangingwall stability and support requirements for the panels between pillars

CSIR Research Space (South Africa)

York, G

1998-12-01

Full Text Available The design of hard rock pillars, in shallow to intermediate depth hard rock mines, has been redefined as the determination of the pillar system load bearing capacity. This entails the ability to design each of the components of the pillar system...

Near-field thermal transient and thermomechanical stress analysis of a disposal vault in crystalline hard rock

International Nuclear Information System (INIS)

Tsui, K.K.; Tsai, A.; Lee, C.F.

1981-01-01

The Canadian Nuclear Fuel Waste Management Program currently focuses on the development of a disposal vault in crystalline hard rock at a reference depth of 1 km below the surface in a suitable pluton in the Canadian Shield. As part of Ontario Hydro's technical assistance to the Atomic Energy of Canada Limited in this program, studies are being carried out to determine the effects of radiogenic heat on the near-field behaviour of a disposal vault. This paper presents the study results obtained to date. Temperature and stress fields were computed and cross-checked by several finite element codes. A comparison between vertical and horizontal borehole emplacement concepts is made. The effects of material non-linearity (temperature dependence) and three-dimensionality on the thermomechanical response are evaluated. Case histories of thermal spalling or fracturing in rock were summarized and discussed to illustrate the possible mechanisms and processes involved in thermal fracturing. An assessment of the thermomechanical stability of the rock mass around a disposal vault under a state of high horizontal in-situ stress is also presented

The influence of environment on the inelastic behavior of rocks

International Nuclear Information System (INIS)

Heard, Hugh C.

1970-01-01

The mechanical response of earth materials are demonstrably dependent upon the environment during deformation as well as the physical properties of the rock masses themselves. Among the most important of these environmental parameters are mean pressure, pore fluid pressure, temperature, strain rate, and the relative magnitude of the intermediate principal stress (σ 2 ) compared to the maximum (σ 1 ) and minimum (σ 3 ) stresses. Important inherent properties of rocks include anisotropy, homogeneity, porosity, permeability, grain size, and mineral composition. Calculation of the response of rocks to a nearby nuclear detonation requires knowledge of the deviatoric stress-strain behavior as well as the resulting mechanisms of deformation: fracture or flow. For calculations beginning at times of the order of 10 -3 sec after detonation, that is, when peak pressures are ∼10 6 bars and lasting to ∼10 2 sec when cavity pressures have decayed to ∼10 2 bars, broad limitations may be imposed on the possible deformation environment. Here, mean pressures range from 10 6 to 10 2 bars, pore pressures from 10 6 to 1 bar, temperatures from 1500 deg. to 50 deg. C, and strain rates from 10 6 to 10 -3 per sec; σ 2 may range in value from that of σ 3 on loading to that of σ 1 on unloading. Using present technology, it is virtually impossible to measure the mechanical behavior of rock materials under controlled conditions over much of the above range. This behavior must be largely inferred from data gathered at less extreme conditions. Quantitative data illustrating the effect of the deformation environment upon the strength and brittle-ductile behavior are presented for a suite of rocks of interest to the Plowshare program; among these are limestone, quartzite, granite, sandstone and 'oil-shale'. More limited results are also presented illustrating the effect of planar anisotropies as well as of grain size upon mechanical properties. The available data then may be used to

Taking into Account the Role of the Weathering Profile in Determining Hydrodynamic Properties of Hard Rock Aquifers

Directory of Open Access Journals (Sweden)

Mahamadou Koïta

2017-09-01

Full Text Available The present study aims at understanding the role of the structure and the geometry of the weathering profile on the hydrodynamic behavior of hard rock aquifers. We first described 2D geophysical cross sections of weathering profiles realized and validated on an experimental site. Next, we implemented five long-term pumping tests in wells drilled at various locations of these cross sections. Finally, we chose the appropriate analytical solutions to determine the hydrodynamic parameters in consistence with the structure and the geometry of the weathering profile. Results reveal that land covers, weathering type and thickness, presence of no flow boundaries, etc. are all factors that explain the flow regime, which appears therefore much less unpredictable. In other words, the 2D geophysical data are enough to locate the best permeable areas, or the areas where the structure of the aquifer without impervious boundaries and with leakage favor a good long-term behavior of the well. The values of aquifer’s transmissivity vary between 5.10−3 and 4.10−5 m2/s. The storage varies between 0.06 and 7.10−7. The variability of these parameters from site to site reflects the high heterogeneity of hard rock aquifers.

Why 1D electrical resistivity techniques can result in inaccurate siting of boreholes in hard rock aquifers and why electrical resistivity tomography must be preferred: the example of Benin, West Africa

Science.gov (United States)

Alle, Iboukoun Christian; Descloitres, Marc; Vouillamoz, Jean-Michel; Yalo, Nicaise; Lawson, Fabrice Messan Amen; Adihou, Akonfa Consolas

2018-03-01

Hard rock aquifers are of particular importance for supplying people with drinking water in Africa and in the world. Although the common use of one-dimensional (1D) electrical resistivity techniques to locate drilling site, the failure rate of boreholes is usually high. For instance, about 40% of boreholes drilled in hard rock aquifers in Benin are unsuccessful. This study investigates why the current use of 1D techniques (e.g. electrical profiling and electrical sounding) can result in inaccurate siting of boreholes, and checks the interest and the limitations of the use of two-dimensional (2D) Electrical Resistivity Tomography (ERT). Geophysical numerical modeling and comprehensive 1D and 2D resistivity surveys were carried out in hard rock aquifers in Benin. The experiments carried out at 7 sites located in different hard rock groups confirmed the results of the numerical modeling: the current use of 1D techniques can frequently leads to inaccurate siting, and ERT better reveals hydrogeological targets such as thick weathered zone (e.g. stratiform fractured layer and preferential weathering associated with subvertical fractured zone). Moreover, a cost analysis demonstrates that the use of ERT can save money at the scale of a drilling programme if ERT improves the success rate by only 5% as compared to the success rate obtained with 1D techniques. Finally, this study demonstrates, using the example of Benin, that the use of electrical resistivity profiling and sounding for siting boreholes in weathered hard rocks of western Africa should be discarded and replaced by the use of ERT technique, more efficient.

Influence of Subjectivity in Geological Mapping on the Net Penetration Rate Prediction for a Hard Rock TBM

Science.gov (United States)

Seo, Yongbeom; Macias, Francisco Javier; Jakobsen, Pål Drevland; Bruland, Amund

2018-05-01

The net penetration rate of hard rock tunnel boring machines (TBM) is influenced by rock mass degree of fracturing. This influence is taken into account in the NTNU prediction model by the rock mass fracturing factor ( k s). k s is evaluated by geological mapping, the measurement of the orientation of fractures and the spacing of fractures and fracture type. Geological mapping is a subjective procedure. Mapping results can therefore contain considerable uncertainty. The mapping data of a tunnel mapped by three researchers were compared, and the influence of the variation in geological mapping was estimated to assess the influence of subjectivity in geological mapping. This study compares predicted net penetration rates and actual net penetration rates for TBM tunneling (from field data) and suggests mapping methods that can reduce the error related to subjectivity. The main findings of this paper are as follows: (1) variation of mapping data between individuals; (2) effect of observed variation on uncertainty in predicted net penetration rates; (3) influence of mapping methods on the difference between predicted and actual net penetration rate.

Aespoe Hard Rock Laboratory. Annual Report 2001

Energy Technology Data Exchange (ETDEWEB)

NONE

2002-09-01

The Aespoe Hard Rock Laboratory (HRL) constitutes an important part of SKB's work to design and construct a deep geological repository for spent nuclear fuel and to develop and test methods for characterisation of a suitable site for a deep repository. One of the fundamental reasons behind SKB's decision to construct an underground laboratory was to create an opportunity for research, development and demonstration in a realistic and undisturbed rock environment down to repository depth. The bedrock with available fractures and fracture zones, its properties and on-going physical, chemical and biological processes which affect the integrity of the engineered barriers and the transport of radionuclides are denoted the natural barriers of a deep repository. Experiments are performed at Aespoe HRL at conditions that are expected to prevail at repository depth, with the aim to increase the knowledge of the long term function of the repository barriers. Another aim with the Aespoe HRL is testing of models for groundwater flow, radionuclide migration, chemical and biological processes. The programme for the testing of models includes evaluation of the usefulness and reliability of different models and the development and testing of methods for determination of parameters required as input to conceptual and numerical models. Ongoing projects are Tracer Retention Understanding Experiments, Long Term Diffusion Experiment, Radionuclide Retention Experiment, Microbial Project, Colloid Project, and Matrix Water Chemistry Experiments. The activities at Aespoe HRL include the evaluation of the usefulness and reliability of different calculation models and the development and testing of methods for determination of parameters required as input to the models. An important part of this work is performed in the Aespoe Task Force on Modelling of Groundwater Flow and Transport of Solutes, an international co-operation project. The work within the Tasks 4 and 5 were reported

Aespoe Hard Rock Laboratory. Annual Report 2001

International Nuclear Information System (INIS)

2002-09-01

The Aespoe Hard Rock Laboratory (HRL) constitutes an important part of SKB's work to design and construct a deep geological repository for spent nuclear fuel and to develop and test methods for characterisation of a suitable site for a deep repository. One of the fundamental reasons behind SKB's decision to construct an underground laboratory was to create an opportunity for research, development and demonstration in a realistic and undisturbed rock environment down to repository depth. The bedrock with available fractures and fracture zones, its properties and on-going physical, chemical and biological processes which affect the integrity of the engineered barriers and the transport of radionuclides are denoted the natural barriers of a deep repository. Experiments are performed at Aespoe HRL at conditions that are expected to prevail at repository depth, with the aim to increase the knowledge of the long term function of the repository barriers. Another aim with the Aespoe HRL is testing of models for groundwater flow, radionuclide migration, chemical and biological processes. The programme for the testing of models includes evaluation of the usefulness and reliability of different models and the development and testing of methods for determination of parameters required as input to conceptual and numerical models. Ongoing projects are Tracer Retention Understanding Experiments, Long Term Diffusion Experiment, Radionuclide Retention Experiment, Microbial Project, Colloid Project, and Matrix Water Chemistry Experiments. The activities at Aespoe HRL include the evaluation of the usefulness and reliability of different calculation models and the development and testing of methods for determination of parameters required as input to the models. An important part of this work is performed in the Aespoe Task Force on Modelling of Groundwater Flow and Transport of Solutes, an international co-operation project. The work within the Tasks 4 and 5 were reported during 2001

Geomass: geological modelling analysis and simulation software for the characterisation of fractured hard rock environments

International Nuclear Information System (INIS)

White, M.J.; Humm, J.P.; Todaka, N.; Takeuchi, S.

1998-01-01

This paper presents the development and functionality of a suite of applications which are being developed to support the geological investigations in the Tono URL. GEOMASS will include 3D geological modelling, 3D fluid flow and solute transport and 3D visualisation capabilities. The 3D geological modelling in GEOMASS will be undertaken using a commercially available 3D geological modelling system, EarthVision. EarthVision provides 3D mapping, interpolation, analysis and well planning software. It is being used in the GEOMASS system to provide the geological framework (structure of the tectonic faults and stratigraphic and lithological contacts) to the 3D flow code. It is also being used to gather the geological data into a standard format for use throughout the investigation programme. The 3D flow solver to be used in GEOMASS is called Frac-Affinity. Frac-Affinity models the 3D geometry of the flow system as a hybrid medium, in which the rock contains both permeable, intact rock and fractures. Frac-Affinity also performs interpolation of heterogeneous rock mass property data using a fractal based approach and the generation of stochastic fracture networks. The code solves for transient flow over a user defined sub-region of the geological framework supplied by EarthVision. The results from Frac-Affinity are passed back to EarthVision so that the flow simulation can be visualized alongside the geological structure. This work-flow allows rapid assessment of the role of geological features in controlling flow. This paper will present the concepts and approach of GEOMASS and illustrate the practical application of GEOMASS using data from Tono

The influence of environment on the inelastic behavior of rocks

Energy Technology Data Exchange (ETDEWEB)

Heard, Hugh C [Lawrence Radiation Laboratory, University of California, Livermore, CA (United States)

1970-05-01

The mechanical response of earth materials are demonstrably dependent upon the environment during deformation as well as the physical properties of the rock masses themselves. Among the most important of these environmental parameters are mean pressure, pore fluid pressure, temperature, strain rate, and the relative magnitude of the intermediate principal stress ({sigma}{sub 2}) compared to the maximum ({sigma}{sub 1}) and minimum ({sigma}{sub 3}) stresses. Important inherent properties of rocks include anisotropy, homogeneity, porosity, permeability, grain size, and mineral composition. Calculation of the response of rocks to a nearby nuclear detonation requires knowledge of the deviatoric stress-strain behavior as well as the resulting mechanisms of deformation: fracture or flow. For calculations beginning at times of the order of 10{sup -3} sec after detonation, that is, when peak pressures are {approx}10{sup 6} bars and lasting to {approx}10{sup 2} sec when cavity pressures have decayed to {approx}10{sup 2} bars, broad limitations may be imposed on the possible deformation environment. Here, mean pressures range from 10{sup 6} to 10{sup 2} bars, pore pressures from 10{sup 6} to 1 bar, temperatures from 1500 deg. to 50 deg. C, and strain rates from 10{sup 6} to 10{sup -3} per sec; {sigma}{sub 2} may range in value from that of {sigma}{sub 3} on loading to that of {sigma}{sub 1} on unloading. Using present technology, it is virtually impossible to measure the mechanical behavior of rock materials under controlled conditions over much of the above range. This behavior must be largely inferred from data gathered at less extreme conditions. Quantitative data illustrating the effect of the deformation environment upon the strength and brittle-ductile behavior are presented for a suite of rocks of interest to the Plowshare program; among these are limestone, quartzite, granite, sandstone and 'oil-shale'. More limited results are also presented illustrating the effect

Subcritical crack growth and other time- and environment-dependent behavior in crustal rocks

Science.gov (United States)

Swanson, P. L.

1984-01-01

Stable crack growth strongly influences both the fracture strength of brittle rocks and some of the phenomena precursory to catastrophic failure. Quantification of the time and environment dependence of fracture propagation is attempted with the use of a fracture mechanics technique. Some of the difficulties encountered when applying techniques originally developed for simple synthetic materials to complex materials like rocks are examined. A picture of subcritical fracture propagation is developed that embraces the essential ingredients of the microstructure, a microcrack process zone, and the different roles that the environment plays. To do this, the results of (1) fracture mechanics experiments on five rock types, (2) optical and scanning electron microscopy, (3) studies of microstructural aspects of fracture in ceramics, and (4) exploratory tests examining the time-dependent response of rock to the application of water are examined.

Inclusion of Radiation Environment Variability in Total Dose Hardness Assurance Methodology

Science.gov (United States)

Xapsos, M. A.; Stauffer, C.; Phan, A.; McClure, S. S.; Ladbury, R. L.; Pellish, J. A.; Campola, M. J.; LaBel, K. A.

2016-01-01

Variability of the space radiation environment is investigated with regard to parts categorization for total dose hardness assurance methods. It is shown that it can have a significant impact. A modified approach is developed that uses current environment models more consistently and replaces the radiation design margin concept with one of failure probability during a mission.

Depositional environment and source rock potential of Cenomanian and Turonian sedimentary rocks of the Tarfaya Basin, Southwest Morocco

Energy Technology Data Exchange (ETDEWEB)

Ghassal, B.I.; Littke, R.; Sachse, V.; Sindern, S.; Schwarzbauer, J.

2016-07-01

Detailed organic and inorganic geochemical analyses were used to assess the depositional environment and source rock potential of the Cenomanian and Turonian oil shale deposits in the Tarfaya Basin. This study is based on core samples from the Tarfaya Sondage-4 well that penetrated over 300m of Mid Cretaceous organic matter-rich deposits. A total of 242 samples were analyzed for total organic and inorganic carbon and selected samples for total sulfur and major elements as well as for organic petrology, Rock-Eval pyrolysis, Curie-Point-pyrolysis-gaschromatography-Mass-Spectrometry and molecular geochemistry of solvent extracts. Based on major elements the lower Cenomanian differs from the other intervals by higher silicate and lower carbonate contents. Moreover, the molecular geochemistry suggests anoxic bottom marine water conditions during the Cenomanian-Turonian Boundary Event (CTBE; Oceanic Anoxic Event 2: OAE2). As a proxy for the Sorg/Corg ratio, the ratio total thiophenes/total benzenes compounds was calculated from pyrolysate compositions. The results suggest that Sorg/ Corg is low in the lower Cenomanian, moderate in the upper Cenomanian, very high in the CTBE (CenomanianTuronian Boundary Event) and high in the Turonian samples. Rock-Eval data reveal that the lower Cenomanian is a moderately organic carbon-rich source rock with good potential to generate oil and gas upon thermal maturation. On the other hand, the samples from the upper Cenomanian to Turonian exhibit higher organic carbon content and can be classified as oil-prone source rocks. Based on Tmax data, all rocks are thermally immature. The microscopic investigations suggest dominance of submicroscopic organic matter in all samples and different contents of bituminite and alginite. The lower Cenomanian samples have little visible organic matter and no bituminite. The upper Cenomanian and CTBE samples are poor in bituminite and have rare visible organic matter, whereas the Turonian samples change

Rock excavation by pulsed electron beams

International Nuclear Information System (INIS)

Avery, R.T.; Keefe, D.; Brekke, T.L.; Finnie, I.

1976-03-01

If an intense short pulse of megavolt electrons is deposited in a brittle solid, dynamic spalling can be made to occur with removal of material. Experiments were made on several types of hard rock; results are reproducible and well-described theoretically. An accelerator with a rapidly-pulsed scanning electron beam was designed that could tunnel in hard rock about ten times faster than conventional drill/blast methods

Studies on the recovery of REEY from a hard-rock deposit of Rajasthan

International Nuclear Information System (INIS)

Karan, Ram; Giri, Nitai; Anand Rao, K.; Sreenivas, T.

2017-01-01

Dantala area in Banner district of Rajasthan is endowed with poly metallic mineralization hosted in tuffaceous rocks consisting of REE, Zr, Nb, U Th, Zn and Ag. The region has potential to become a hardrock rare earth resource in India. The chemical and XRF analysis of a representative borehole sample revealed that the ore has about 68% SiO_2, 7.7% Al_2O_3, 7.4% Fe_2O_3, 4.75% CaO along with 305 ppm Nb, 109 ppm Th, 3738 ppm TREE of which, 2580 ppm is LREE and 1158 ppm is HREE including 777 ppm Y. The deportment profile of REEY in the sample determined by sequential chemical extraction technique. Major distribution of REEY is dissolvable only under highly acidic conditions as the REEY are bound to iron oxides and are associated with refractory phases (zircon?). Heavy media separation of coarsely crushed material showed presence of about 90% of REEY values in specific gravity d'' 2.8. Therefore, the REEY values could not be preconcentrated by conventional physical beneficiation techniques. Direct 'whole ore' leaching using HCL and H_2SO_4 in 'pug cure leaching' mode with H_2SO_4 yielded about 50% dissolution of REEY values. The paper discusses the process complexities in the recovery of REEY from this hard rock ore sample

Aespoe Hard Rock Laboratory. Prototype Repository. Acoustic emission and ultrasonic monitoring results from deposition hole DA3545G01 in the Prototype Repository between April 2008 and September 2008

Energy Technology Data Exchange (ETDEWEB)

Duckworth, D.; Haycox, J.; Pettitt, W.S. (Applied Seismology Consultants, Shrewsbury (United Kingdom))

2009-03-15

This report describes results from acoustic emission (AE) and ultrasonic monitoring around a canister deposition hole (DA3545G01) in the Prototype Repository Experiment at SKB's Hard Rock Laboratory (HRL), Sweden. The monitoring aims to examine changes in the rock mass caused by an experimental repository environment, in particular due to thermal stresses induced from canister heating and pore pressures induced from tunnel sealing. Monitoring of this volume has previously been performed during excavation [Pettitt et al., 1999], and during stages of canister heating and tunnel pressurisation [Haycox et al., 2005a and 2005b; Haycox et al., 2006a and 2006b; Zolezzi et al., 2007 and Duckworth et al., 2008]. Further information on this monitoring can be found in Appendix I. This report covers the period between 1st April 2008 and 30th September 2008 and is the seventh instalment of the 6-monthly processing and interpretation of the results from the experiment.

Aespoe Hard Rock Laboratory. Prototype Repository. Acoustic emission and ultrasonic monitoring results from deposition hole DA3545G01 in the Prototype Repository between April 2008 and September 2008

International Nuclear Information System (INIS)

Duckworth, D.; Haycox, J.; Pettitt, W.S.

2009-03-01

This report describes results from acoustic emission (AE) and ultrasonic monitoring around a canister deposition hole (DA3545G01) in the Prototype Repository Experiment at SKB's Hard Rock Laboratory (HRL), Sweden. The monitoring aims to examine changes in the rock mass caused by an experimental repository environment, in particular due to thermal stresses induced from canister heating and pore pressures induced from tunnel sealing. Monitoring of this volume has previously been performed during excavation [Pettitt et al., 1999], and during stages of canister heating and tunnel pressurisation [Haycox et al., 2005a and 2005b; Haycox et al., 2006a and 2006b; Zolezzi et al., 2007 and Duckworth et al., 2008]. Further information on this monitoring can be found in Appendix I. This report covers the period between 1st April 2008 and 30th September 2008 and is the seventh instalment of the 6-monthly processing and interpretation of the results from the experiment

Hydraulic fracture monitoring in hard rock at 410 m depth with an advanced fluid-injection protocol and extensive sensor array

Science.gov (United States)

Zang, Arno; Stephansson, Ove; Stenberg, Leif; Plenkers, Katrin; Specht, Sebastian; Milkereit, Claus; Schill, Eva; Kwiatek, Grzegorz; Dresen, Georg; Zimmermann, Günter; Dahm, Torsten; Weber, Michael

2017-02-01

In this paper, an underground experiment at the Äspö Hard Rock Laboratory (HRL) is described. Main goal is optimizing geothermal heat exchange in crystalline rock mass at depth by multistage hydraulic fracturing with minimal impact on the environment, that is, seismic events. For this, three arrays with acoustic emission, microseismicity and electromagnetic sensors are installed mapping hydraulic fracture initiation and growth. Fractures are driven by three different water injection schemes (continuous, progressive and pulse pressurization). After a brief review of hydraulic fracture operations in crystalline rock mass at mine scale, the site geology and the stress conditions at Äspö HRL are described. Then, the continuous, single-flow rate and alternative, multiple-flow rate fracture breakdown tests in a horizontal borehole at depth level 410 m are described together with the monitoring networks and sensitivity. Monitoring results include the primary catalogue of acoustic emission hypocentres obtained from four hydraulic fractures with the in situ trigger and localizing network. The continuous versus alternative water injection schemes are discussed in terms of the fracture breakdown pressure, the fracture pattern from impression packer result and the monitoring at the arrays. An example of multistage hydraulic fracturing with several phases of opening and closing of fracture walls is evaluated using data from acoustic emissions, seismic broad-band recordings and electromagnetic signal response. Based on our limited amount of in situ tests (six) and evaluation of three tests in Ävrö granodiorite, in the multiple-flow rate test with progressively increasing target pressure, the acoustic emission activity starts at a later stage in the fracturing process compared to the conventional fracturing case with continuous water injection. In tendency, also the total number and magnitude of acoustic events are found to be smaller in the progressive treatment with

Rock excavation by pulsed electron beams

International Nuclear Information System (INIS)

Avery, R.T.; Keefe, D.; Brekke, T.L.; Finnie, I.

1976-01-01

If an intense short pulse of megavolt electrons is deposited in a brittle solid, dynamic spalling can be made to occur with removal of material. Experiments have been made on several types of hard rock; results are reproducible and well-described theoretically. An accelerator with a rapid-pulsed scanning electron-beam has been designed that could tunnel in hard rock about ten times faster than conventional drill/blast methods. (author)

Case histories of roller cone core bit application in crystalline rock

International Nuclear Information System (INIS)

Dahlem, J.S.

1988-01-01

The increased interest in deep crystalline rock drilling projects has resulted in a requirement for premium coring bits which are effective in such a harsh and abrasive environment. Hard formation roller cone insert bits have traditionally and constantly performed well in crystalline rock. As a result, the application of state of the art roller cone rock bit technology to the design and development of core bits has made crystalline coring projects more viable than ever before. This paper follows the development of roller cone core bits by examining their use on project such as HDR (Hot Dry Rock, Los Alamos); NAGRA (Nuclear Waste Disposal Wells in Switzerland); Camborne School of Mines Geothermal Project in Cornwall, UK; Deep Gas Project in Sweden; and the KTB Deep Drilling Project in West Germany

Aespoe Hard Rock Laboratory. Hydro Monitoring Program. Report for 2008

Energy Technology Data Exchange (ETDEWEB)

Wass, Eva; Nyberg, Goeran (GEOSIGMA, Uppsala (Sweden))

2009-08-15

The Aespoe island is situated close to the nuclear power plant of Simpevarp in southeastern Sweden. As part of the pre-investigations preceding excavation of the Aespoe Hard Rock Laboratory, registrations of the groundwater levels and electrical conductivity in packed-off borehole sections and levels in open boreholes started in 1987. The investigations are still ongoing and are planned to continue for a long period of time. As the tunnel excavation went on from the autumn 1990 and onwards, new boreholes were drilled in the tunnel and instrumented to enable groundwater pressure monitoring in packed-off sections. In addition, other hydro-related measurements such as water flow in the tunnel, electrical conductivity of tunnel water and inflow and outflow of water through tunnel pipes have been performed. This report is a summary of the monitoring during 2008. In order to allow for comparison with factors that may influence the groundwater level/pressure and flow, meteorological data are also presented in the report. From the end of 1991, the disturbance from the tunnel is the dominating factor influencing groundwater levels in the area. In one chapter, activities that may have an influence on the ground water situation are listed and briefly discussed.

Aespoe Hard Rock Laboratory. Hydro Monitoring Program. Report for 2009

Energy Technology Data Exchange (ETDEWEB)

Wass, Eva; Nyberg, Goeran (GEOSIGMA, Uppsala (Sweden))

2010-05-15

The Aespoe island is situated close to the nuclear power plant of Simpevarp in southeastern Sweden. As part of the pre-investigations preceding excavation of the Aespoe Hard Rock Laboratory, registrations of the groundwater levels and electrical conductivity in packed-off borehole sections and levels in open boreholes started in 1987. The investigations are still ongoing and are planned to continue for a long period of time. As the tunnel excavation went on from the autumn 1990 and onwards, new boreholes were drilled in the tunnel and instrumented to enable groundwater pressure monitoring in packed-off sections. In addition, other hydro-related measurements such as water flow in the tunnel, electrical conductivity of tunnel water and inflow and outflow of water through tunnel pipes have been performed. This report is a summary of the monitoring during 2009. In order to allow for comparison with factors that may influence the groundwater level/pressure and flow, meteorological data are also presented in the report. From the end of 1991, the disturbance from the tunnel is the dominating factor influencing groundwater levels in the area. In one chapter, activities that may have an influence on the ground water situation are listed and briefly discussed

Aespoe Hard Rock Laboratory. Hydro Monitoring Program. Report for 2008

International Nuclear Information System (INIS)

Wass, Eva; Nyberg, Goeran

2009-08-01

The Aespoe island is situated close to the nuclear power plant of Simpevarp in southeastern Sweden. As part of the pre-investigations preceding excavation of the Aespoe Hard Rock Laboratory, registrations of the groundwater levels and electrical conductivity in packed-off borehole sections and levels in open boreholes started in 1987. The investigations are still ongoing and are planned to continue for a long period of time. As the tunnel excavation went on from the autumn 1990 and onwards, new boreholes were drilled in the tunnel and instrumented to enable groundwater pressure monitoring in packed-off sections. In addition, other hydro-related measurements such as water flow in the tunnel, electrical conductivity of tunnel water and inflow and outflow of water through tunnel pipes have been performed. This report is a summary of the monitoring during 2008. In order to allow for comparison with factors that may influence the groundwater level/pressure and flow, meteorological data are also presented in the report. From the end of 1991, the disturbance from the tunnel is the dominating factor influencing groundwater levels in the area. In one chapter, activities that may have an influence on the ground water situation are listed and briefly discussed

Aespoe Hard Rock Laboratory. Hydro Monitoring Program. Report for 2009

International Nuclear Information System (INIS)

Wass, Eva; Nyberg, Goeran

2010-05-01

The Aespoe island is situated close to the nuclear power plant of Simpevarp in southeastern Sweden. As part of the pre-investigations preceding excavation of the Aespoe Hard Rock Laboratory, registrations of the groundwater levels and electrical conductivity in packed-off borehole sections and levels in open boreholes started in 1987. The investigations are still ongoing and are planned to continue for a long period of time. As the tunnel excavation went on from the autumn 1990 and onwards, new boreholes were drilled in the tunnel and instrumented to enable groundwater pressure monitoring in packed-off sections. In addition, other hydro-related measurements such as water flow in the tunnel, electrical conductivity of tunnel water and inflow and outflow of water through tunnel pipes have been performed. This report is a summary of the monitoring during 2009. In order to allow for comparison with factors that may influence the groundwater level/pressure and flow, meteorological data are also presented in the report. From the end of 1991, the disturbance from the tunnel is the dominating factor influencing groundwater levels in the area. In one chapter, activities that may have an influence on the ground water situation are listed and briefly discussed

Rock burst governance of working face under igneous rock

Science.gov (United States)

Chang, Zhenxing; Yu, Yue

2017-01-01

As a typical failure phenomenon, rock burst occurs in many mines. It can not only cause the working face to cease production, but also cause serious damage to production equipment, and even result in casualties. To explore how to govern rock burst of working face under igneous rock, the 10416 working face in some mine is taken as engineering background. The supports damaged extensively and rock burst took place when the working face advanced. This paper establishes the mechanical model and conducts theoretical analysis and calculation to predict the fracture and migration mechanism and energy release of the thick hard igneous rock above the working face, and to obtain the advancing distance of the working face when the igneous rock fractures and critical value of the energy when rock burst occurs. Based on the specific conditions of the mine, this paper put forward three kinds of governance measures, which are borehole pressure relief, coal seam water injection and blasting pressure relief.

An Analysis of a Hard Real-Time Execution Environment Extension for FreeRTOS

Directory of Open Access Journals (Sweden)

STANGACIU, C.

2015-08-01

Full Text Available FreeRTOS is a popular real-time operating system, which has been under a significant attention in the last years due to its main advantages: it is open source, portable, well documented and implemented on more than 30 architectures. FreeRTOS execution environment is dynamic, preemptive and priority based, but it is not suitable for hard real-time tasks, because it provides task execution determinism only to a certain degree and cannot guarantee the absence of task execution jitter. As a solution to this problem, we propose a hard real time execution extension to FreeRTOS in order to support a particular model of HRT tasks, called ModXs, which are executed with no jitter. This article presents a detailed analysis, in terms of scheduling, task execution and memory usage of this hard real time execution environment extension. The article is concluding with the advantages this extension brings to the system compared to the small memory and timing overhead introduced.

Swedish-German actinide migration experiment at ÄSPÖ hard rock laboratory

Science.gov (United States)

Kienzler, B.; Vejmelka, P.; Römer, J.; Fanghänel, E.; Jansson, M.; Eriksen, T. E.; Wikberg, P.

2003-03-01

Within the scope of a bilateral cooperation between Svensk Kärnbränslehantering (SKB) and Forschungszentrum Karlsruhe, Institut für Nukleare Entsorgung (FZK-INE), an actinide migration experiment is currently being performed at the Äspö Hard Rock Laboratory (HRL) in Sweden. This paper covers laboratory and in situ investigations on actinide migration in single-fractured granite core samples. For the in situ experiment, the CHEMLAB 2 probe developed by SKB was used. The experimental setup as well as the breakthrough of inert tracers and of the actinides Am, Np and Pu are presented. The breakthrough curves of inert tracers were analyzed to determine hydraulic properties of the fractured samples. Postmortem analyses of the solid samples were performed to characterize the flow path and the sorbed actinides. After cutting the cores, the abraded material was analyzed with respect to sorbed actinides. The slices were scanned optically to visualize the flow path. Effective volumes and inner surface areas were measured. In the experiments, only breakthrough of Np(V) was observed. In each experiment, the recovery of Np(V) was ≤40%. Breakthrough of Am(III) and Pu(IV) as well as of Np(IV) was not observed.

Comparison of thermally induced and naturally occurring water-borne leakages from hard rock depositories for radioactive waste

International Nuclear Information System (INIS)

Bourke, P.J.; Robinson, P.C.

1981-01-01

The relative importance of thermally induced and naturally occurring flows of water as causes of leakage from hard rock depositories for radioactive wastes is assessed. Separate analyses are presented for involatile, high level waste from reprocessing of fuel and for plutonium contaminated waste from fabrication of fuel. The effects of varying the quantities of wastes, pre-burial storage and the shapes and depths of depositories are considered. It is concluded that for representative values of these variables, thermal flow will remain the major cause of leakage for long times after the burial of both types of waste. (Auth.)

Rock index properties for geoengineering in underground development

International Nuclear Information System (INIS)

O'Rourke, J.E.

1989-01-01

This paper describes the use of index testing to obtain rock properties that are useful in the design and construction planning of an underground development for civil engineering or mining projects. The index properties discussed include: point load; Schmidt hammer hardness; abrasion hardness; and total hardness. The first two index properties correlate to uniaxial compressive strength (UCS) and Young's modulus. Discussions are given on empirical, normalized relationships of UCS to rock mass properties and the integrated use with semi-empirical, geotechnical design methods. The hardness property indices correlate to construction performance parameters and some relevant experience is cited. Examples of data are presented from an index testing program carried out primarily on siltstone, sandstone and limestone rock core samples retrieved from depths up to 1005 m (3300 ft) in a borehole drilled in the Paradox Basin in eastern Utah. The borehole coring was done for a nuclear waste repository site investigation

Sampling and treatment of rock cores and groundwater under reducing environments of deep underground

International Nuclear Information System (INIS)

Ebashi, Katsuhiro; Yamaguchi, Tetsuji; Tanaka, Tadao

2005-01-01

A method of sampling and treatment of undisturbed rock cores and groundwater under maintained reducing environments of deep underground was developed and demonstrated in a Neogene's sandy mudstone layer at depth of GL-100 to -200 m. Undisturbed rock cores and groundwater were sampled and transferred into an Ar gas atmospheric glove box with minimized exposure to the atmosphere. The reducing conditions of the sampled groundwater and rock cores were examined in the Ar atmospheric glove box by measuring pH and Eh of the sampled groundwater and sampled groundwater contacting with disk type rock samples, respectively. (author)

Extremely environment-hard and low work function transfer-mold field emitter arrays

Energy Technology Data Exchange (ETDEWEB)

Nakamoto, Masayuki, E-mail: m-nakamoto@rie.shizuoka.ac.jp [Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu, Shizuoka 432-8011 (Japan); Moon, Jonghyun [Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu, Shizuoka 432-8011 (Japan)

2013-06-15

Extremely environment-hard and low work function field-emitter arrays (FEAs) were fabricated by a transfer-mold emitter fabrication method to produce highly reliable vacuum nanoelectronic devices able to operate stably at low voltage in highly oxidizing atmospheres. Amorphous carbon (a-C) having a work function of 3.6 eV and sp{sup 3} fraction of 85.6% prepared by plasma-enhanced chemical vapor deposition was used as the emitter material. The field-emission characteristics of the obtained transfer-mold FEAs strongly depended on their work function and morphology. The environment-hard characteristics of the transfer-mold a-C FEAs were compared with those of the transfer-mold titanium nitride FEAs and nickel FEAs. X-ray photoelectron spectroscopy was used to confirm the stable chemical states of the FEAs after oxygen radical treatment. The small amount of material oxidized (6.3%) at the surface of the a-C FEAs compared with 11.8% for the TiN-FEAs and 39.0% for Ni FEAs after oxygen radical treatment explained their almost constant work function in oxidizing atmospheres. The emission fluctuation rates of transfer-mold a-C FEAs without resistive layers under in situ radical treatment were as low as ±5.0%, compared with 5–100% for conventional FEAs with resistive layers not under highly oxidizing atmospheres. Therefore, the present environment-hard and low work function transfer-mold a-C FEAs are expected to be useful for reliable vacuum nanoelectronic devices.

GaN-Based High Temperature and Radiation-Hard Electronics for Harsh Environments

Science.gov (United States)

Son, Kyung-ah; Liao, Anna; Lung, Gerald; Gallegos, Manuel; Hatakeh, Toshiro; Harris, Richard D.; Scheick, Leif Z.; Smythe, William D.

2010-01-01

We develop novel GaN-based high temperature and radiation-hard electronics to realize data acquisition electronics and transmitters suitable for operations in harsh planetary environments. In this paper, we discuss our research on metal-oxide-semiconductor (MOS) transistors that are targeted for 500 (sup o)C operation and >2 Mrad radiation hardness. For the target device performance, we develop Schottky-free AlGaN/GaN MOS transistors, where a gate electrode is processed in a MOS layout using an Al2O3 gate dielectric layer....

A Rock Mechanics and Coupled Hydro mechanical Analysis of Geological Repository of High Level Nuclear Waste in Fractured Rocks

International Nuclear Information System (INIS)

Min, Kibok

2011-01-01

This paper introduces a few case studies on fractured hard rock based on geological data from Sweden, Korea is one of a few countries where crystalline rock is the most promising rock formation as a candidate site of geological repository of high level nuclear waste. Despite the progress made in the area of rock mechanics and coupled hydro mechanics, extensive site specific study on multiple candidate sites is essential in order to choose the optimal site. For many countries concerned about the safe isolation of nuclear wastes from the biosphere, disposal in a deep geological formation is considered an attractive option. In geological repository, thermal loading continuously disturbs the repository system in addition to disturbances a recent development in rock mechanics and coupled hydro mechanical study using DFN(Discrete Fracture Network) - DEM(Discrete Element Method) approach mainly applied in hard, crystalline rock containing numerous fracture which are main sources of deformation and groundwater flow

Characterization and differentiation of rock varnish types from different environments by microanalytical techniques

Energy Technology Data Exchange (ETDEWEB)

Macholdt, D. S. [Max Planck Society, Mainz (Germany). Max Planck Inst. for Chemistry; Jochum, K. P. [Max Planck Society, Mainz (Germany). Max Planck Inst. for Chemistry; Pöhlker, C. [Max Planck Society, Mainz (Germany). Max Planck Inst. for Chemistry; Arangio, A. [Max Planck Society, Mainz (Germany). Max Planck Inst. for Chemistry; Förster, J. -D. [Max Planck Society, Mainz (Germany). Max Planck Inst. for Chemistry; Stoll, B. [Max Planck Society, Mainz (Germany). Max Planck Inst. for Chemistry; Weis, U. [Max Planck Society, Mainz (Germany). Max Planck Inst. for Chemistry; Weber, B. [Max Planck Society, Mainz (Germany). Max Planck Inst. for Chemistry; Müller, M. [Max Planck Inst. for Polymer Research, Mainz (Germany); Kappl, M. [Max Planck Inst. for Polymer Research, Mainz (Germany); Shiraiwa, M. [Max Planck Society, Mainz (Germany). Max Planck Inst. for Chemistry; Kilcoyne, A. L. D. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Weigand, M. [Max Planck Inst. for Intelligent Systems, Stuttgart (Germany); Scholz, D. [Johannes Gutenberg Univ., Mainz (Germany); Haug, G. H. [Max Planck Society, Mainz (Germany). Max Planck Inst. for Chemistry; Al-Amri, A. [King Saud Univ., Riyadh (Saudi Arabia); Andreae, M. O. [Max Planck Society, Mainz (Germany). Max Planck Inst. for Chemistry; King Saud Univ., Riyadh (Saudi Arabia)

2017-04-13

We investigated rock varnishes collected from several locations and environments worldwide by a wide range of microanalytical techniques. These techniques were selected to address the challenges posed by the chemical and structural complexity within the micrometer- to nanometer-sized structures in these geological materials. Femtosecond laser ablation-inductively coupled plasma-mass spectrometry (fs LA-ICP-MS), scanning transmission X-ray microscopy-near edge X-ray adsorption fine structure spectroscopy (STXM-NEXAFS) in combination with scanning electron microscopy (SEM) of focused ion beam (FIB) ultra-thin (100–200 nm) sections, conventional and polarization microscopy, as well as electron paramagnetic resonance (EPR) measurements were used to obtain information about these rock varnishes. Rock varnishes from different environments, which cannot readily be distinguished based on their macroscopic appearance, differ significantly in their constituent elemental mass fractions, e.g., of Mn, Fe, Ni, Co, Ba, and Pb, and their rare earth element (REE) patterns. Structural characteristics such as the particle sizes of embedded dust grains, internal structures such as layers of Mn-, Fe-, and Ca -rich material, and structures such as cavities varied between varnishes from different environments and regions in the world. The EPR spectra were consistent with aged biogenic Mn oxides in all samples, but showed subtle differences between samples of different origin. Our observations allow us to separate rock varnishes into different types, with differences that might be indicators of distinct geneses. Five different types of rock varnish could be distinguished, Type I–V, of which only Type I might be used as potential paleoclimate archive. Each varnish type has specific characteristics in terms of their elemental composition, element distribution, and structures. The combination of element ratios (Mn/Ba, Al/Ni, Mn/REY, Mn/Ce, Mn/Pb, La N /Yb N , and Ce/Ce*), total REE

Aespoe Hard Rock Laboratory. Annual Report 2008

International Nuclear Information System (INIS)

2009-07-01

The Aespoe Hard Rock Laboratory (HRL) is an important part of SKB's work with the design and construction of a deep geological repository for the final disposal of spent nuclear fuel. The main activities in the geoscientific fields have been: (1) Geology - completion of the feasibility study concerning geological mapping techniques and mapping of rock surfaces in the new tunnel, (2) Hydrogeology - monitoring and storage of data in the computerised Hydro Monitoring System, (3) Geochemistry - sampling of groundwater in the yearly campaign and for specific experiments and (4) Rock Mechanics - field tests to evaluate the counterforce needed to prevent thermally-induced spalling in deposition holes. At Aespoe HRL, experiments are performed under the conditions that are expected to prevail at repository depth. The aim is to provide information about the long-term function of natural and repository barriers. Experiments are performed to develop and test methods and models for the description of groundwater flow, radionuclide migration, and chemical conditions at repository depth. The programme includes projects which aim to determine parameter values that are required as input to the conceptual and numerical models. A number of large-scale field experiments and supporting activities concerning Engineered barriers are carried out at Aespoe HRL. The experiments focus on different aspects of engineering technology and performance testing: The Prototype Repository is a demonstration of the integrated function of the repository and provides a full-scale reference for tests of predictive models concerning individual components as well as the complete repository system; The Long Term Test of Buffer Material (Lot-experiment) aims at validating models and hypotheses concerning physical properties in a bentonite buffer material and of related processes regarding microbiology, radionuclide transport, copper corrosion and gas transport; The objective of the project Alternative Buffer

Aespoe Hard Rock Laboratory. Annual Report 2008

Energy Technology Data Exchange (ETDEWEB)

2009-07-15

The Aespoe Hard Rock Laboratory (HRL) is an important part of SKB's work with the design and construction of a deep geological repository for the final disposal of spent nuclear fuel. The main activities in the geoscientific fields have been: (1) Geology - completion of the feasibility study concerning geological mapping techniques and mapping of rock surfaces in the new tunnel, (2) Hydrogeology - monitoring and storage of data in the computerised Hydro Monitoring System, (3) Geochemistry - sampling of groundwater in the yearly campaign and for specific experiments and (4) Rock Mechanics - field tests to evaluate the counterforce needed to prevent thermally-induced spalling in deposition holes. At Aespoe HRL, experiments are performed under the conditions that are expected to prevail at repository depth. The aim is to provide information about the long-term function of natural and repository barriers. Experiments are performed to develop and test methods and models for the description of groundwater flow, radionuclide migration, and chemical conditions at repository depth. The programme includes projects which aim to determine parameter values that are required as input to the conceptual and numerical models. A number of large-scale field experiments and supporting activities concerning Engineered barriers are carried out at Aespoe HRL. The experiments focus on different aspects of engineering technology and performance testing: The Prototype Repository is a demonstration of the integrated function of the repository and provides a full-scale reference for tests of predictive models concerning individual components as well as the complete repository system; The Long Term Test of Buffer Material (Lot-experiment) aims at validating models and hypotheses concerning physical properties in a bentonite buffer material and of related processes regarding microbiology, radionuclide transport, copper corrosion and gas transport; The objective of the project Alternative

Simulating Hydraulic Fracturing: Failure in soft versus hard rocks

Science.gov (United States)

Aleksans, J.; Koehn, D.; Toussaint, R.

2017-12-01

In this contribution we discuss the dynamic development of hydraulic fractures, their evolution and the resulting seismicity during fluid injection in a coupled numerical model. The model describes coupling between a solid that can fracture dynamically and a compressible fluid that can push back at the rock and open fractures. With a series of numerical simulations we show how the fracture pattern and seismicity change depending on changes in depth, injection rate, Young's Modulus and breaking strength. Our simulations indicate that the Young's Modulus has the largest influence on the fracture dynamics and also the related seismicity. Simulations of rocks with a Young's modulus smaller than 10 GPa show dominant mode I failure and a growth of fracture aperture with a decrease in Young's modulus. Simulations of rocks with a higher Young's modulus than 10 GPa show fractures with a constant aperture and fracture growth that is mainly governed by a growth in crack length and an increasing amount of mode II failure. We propose that two distinct failure regimes are observed in the simulations, above 10 GPa rocks break with a constant critical stress intensity factor whereas below 10 GPa they break reaching a critical cohesion, i.e. a critical tensile strength. These results are very important for the prediction of fracture dynamics and seismicity during fluid injection, especially since we see a transition from one failure regime to another at around 10 GPa, a Young's modulus that lies in the middle of possible values for natural shale rocks.

The Rock Cycle or It's Hard When You're a Rock.

Science.gov (United States)

Pugsley, David C.

Produced for primary grades, this booklet provides study of the mineral or rock cycle in nature. Line drawings, a minimum amount of narrative, and a glossary of terms make up its content. The booklet is designed to be used as reading material, a coloring book, or for dramatic arts with students acting out parts of the cycle. This work was prepared…

Progress in 1988 1990 with computer applications in the ``hard-rock'' arena: Geochemistry, mineralogy, petrology, and volcanology

Science.gov (United States)

Rock, Nicholas M. S.

This review covers rock, mineral and isotope geochemistry, mineralogy, igneous and metamorphic petrology, and volcanology. Crystallography, exploration geochemistry, and mineral exploration are excluded. Fairly extended comments on software availability, and on computerization of the publication process and of specimen collection indexes, may interest a wider audience. A proliferation of both published and commercial software in the past 3 years indicates increasing interest in what traditionally has been a rather reluctant sphere of geoscience computer activity. However, much of this software duplicates the same old functions (Harker and triangular plots, mineral recalculations, etc.). It usually is more efficient nowadays to use someone else's program, or to employ the command language in one of many general-purpose spreadsheet or statistical packages available, than to program a specialist operation from scratch in, say, FORTRAN. Greatest activity has been in mineralogy, where several journals specifically encourage publication of computer-related activities, and IMA and MSA Working Groups on microcomputers have been convened. In petrology and geochemistry, large national databases of rock and mineral analyses continue to multiply, whereas the international database IGBA grows slowly; some form of integration is necessary to make these disparate systems of lasting value to the global "hard-rock" community. Total merging or separate addressing via an intelligent "front-end" are both possibilities. In volcanology, the BBC's videodisk Volcanoes and the Smithsonian Institution's Global Volcanism Project use the most up-to-date computer technology in an exciting and innovative way, to promote public education.

The typology of Irish hard-rock aquifers based on an integrated hydrogeological and geophysical approach

Science.gov (United States)

Comte, Jean-Christophe; Cassidy, Rachel; Nitsche, Janka; Ofterdinger, Ulrich; Pilatova, Katarina; Flynn, Raymond

2012-12-01

Groundwater flow in hard-rock aquifers is strongly controlled by the characteristics and distribution of structural heterogeneity. A methodology for catchment-scale characterisation is presented, based on the integration of complementary, multi-scale hydrogeological, geophysical and geological approaches. This was applied to three contrasting catchments underlain by metamorphic rocks in the northern parts of Ireland (Republic of Ireland and Northern Ireland, UK). Cross-validated surface and borehole geophysical investigations confirm the discontinuous overburden, lithological compartmentalisation of the bedrock and important spatial variations of the weathered bedrock profiles at macro-scale. Fracture analysis suggests that the recent (Alpine) tectonic fabric exerts strong control on the internal aquifer structure at meso-scale, which is likely to impact on the anisotropy of aquifer properties. The combination of the interpretation of depth-specific hydraulic-test data with the structural information provided by geophysical tests allows characterisation of the hydrodynamic properties of the identified aquifer units. Regionally, the distribution of hydraulic conductivities can be described by inverse power laws specific to the aquifer litho-type. Observed groundwater flow directions reflect this multi-scale structure. The proposed integrated approach applies widely available investigative tools to identify key dominant structures controlling groundwater flow, characterising the aquifer type for each catchment and resolving the spatial distribution of relevant aquifer units and associated hydrodynamic parameters.

Investigation of the THM behaviour of the buffer and rock-buffer interaction during the canister retrieval test performed in the ASPÖ Hard Rock Laboratory

International Nuclear Information System (INIS)

Millard, A.; Barnichon, J.D.

2014-01-01

In the framework of the THERESA European project, numerical modelling of coupled thermo-hydro-mechanical (THM) and thermo-hydro-mechanical-chemical (THMC) behaviour of buffer (bentonite) and buffer-rock interfaces for deep underground nuclear waste repositories has been undertaken, with focus on the performance assessments. A major step of the project was the analysis of a large scale test, called the Canister Retrieval test, which has been performed in Aspö Hard Rock Laboratory. It consists in a full scale test of the emplacement of a canister with the surrounding buffer material. A deposition hole was first bored, and then the canister with heaters was installed together with bentonite blocks. The gap between the rock and the bentonite blocks was filled with bentonite pellets. The whole set was artificially wetted from its external boundary in order to accelerate the expected natural rehydration by the surrounding rock. The evolution of the THM processes was recorded over 5 years. Before analysing the whole CRT experiment, a preliminary simpler problem has been defined, which consisted in modelling a disc of buffer at canister mid-height. Thanks to the available experimental recorded measurements, it has been possible to numerically investigate the respective influence of the various THM parameters involved in the modelling of the physical processes. The theoretical model is based on one hand on the Richard's approximation for the flow calculation, and on the other hand on a Biot's type model for the hydro-mechanical behaviour. It has revealed the large influence of the liquid relative permeability, which is unfortunately in general not directly available from experiments and must be determined through inverse analysis techniques. Then, in a second stage, the whole CRT experiment has been analysed. For simplicity reasons, an axisymetrical model has been adopted, although the presence of a neighbouring experiment did influence the CRT results. The comparisons of

Investigation of the THM behaviour of the buffer and rock-buffer interaction during the canister retrieval test performed in the ASPÖ Hard Rock Laboratory

Energy Technology Data Exchange (ETDEWEB)

Millard, A., E-mail: alain.millard@cea.fr [CEA, DEN, DANS, DM2S, SEMT, LM2S, F91191 Gif sur Yvette (France); Barnichon, J.D. [IRSN/DEI/SARG/LR2S, F-92260 Fontenay-aux-Roses (France)

2014-04-01

In the framework of the THERESA European project, numerical modelling of coupled thermo-hydro-mechanical (THM) and thermo-hydro-mechanical-chemical (THMC) behaviour of buffer (bentonite) and buffer-rock interfaces for deep underground nuclear waste repositories has been undertaken, with focus on the performance assessments. A major step of the project was the analysis of a large scale test, called the Canister Retrieval test, which has been performed in Aspö Hard Rock Laboratory. It consists in a full scale test of the emplacement of a canister with the surrounding buffer material. A deposition hole was first bored, and then the canister with heaters was installed together with bentonite blocks. The gap between the rock and the bentonite blocks was filled with bentonite pellets. The whole set was artificially wetted from its external boundary in order to accelerate the expected natural rehydration by the surrounding rock. The evolution of the THM processes was recorded over 5 years. Before analysing the whole CRT experiment, a preliminary simpler problem has been defined, which consisted in modelling a disc of buffer at canister mid-height. Thanks to the available experimental recorded measurements, it has been possible to numerically investigate the respective influence of the various THM parameters involved in the modelling of the physical processes. The theoretical model is based on one hand on the Richard's approximation for the flow calculation, and on the other hand on a Biot's type model for the hydro-mechanical behaviour. It has revealed the large influence of the liquid relative permeability, which is unfortunately in general not directly available from experiments and must be determined through inverse analysis techniques. Then, in a second stage, the whole CRT experiment has been analysed. For simplicity reasons, an axisymetrical model has been adopted, although the presence of a neighbouring experiment did influence the CRT results. The

Depositional environments and oil potential of Jurassic/Cretaceous source rocks within the Seychelles microcontinent

Energy Technology Data Exchange (ETDEWEB)

Plummer, P.S.; Joseph, P.R.; Samson, P.J. [Seychelles National Oil Co., Mahe (Seychelles)

1998-12-31

The Seychelles microcontinent became isolated between the Somali, Mascarene and Arabian basins of the Indian Ocean as a result of the Mesozoic fragmentation of Gondwana. Major rifting events occurred during the Triassic-Middle Jurassic and Late Cretaceous (Cenomanian-Santonian and Maastrichtian) during which shaly source rock facies accumulated in principally marginal marine/deltaic environments. Between these times, post-rift passive margin deposition within restricted to open marine environments produced shaly source rocks during late Middle Jurasic-Early Cretaceous, Campanian-Maastrichtian and Paleocene times. Recent geochemical analysis of cuttings from the Seagull Shoals-1 well has identified an oil-prone liptinitic (Type II) coaly shale within early Middle Jurassic abandoned deltaic deposits. This coaly source rock is regionally developed, having also been identified in the Majunja and Morondava basins of Madagascar. Oil-prone Type II organic matter has also been identified in the Owen Bank A-1 well within restricted marine shales of late Middle Jurassic age. These shales are part of a thick post-rift source rock sequence that extends into the Early Cretaceous and is in part correlative with the proven Late Jurassic Uarandab Shale of Somalia. Analysis of Campanian marine shales from Reith Bank-1 well identified significant dilution of total organic carbon content in composite, compared to picked, well cuttings samples. This finding supports a published inference that these post-rift shales have source rock potential. (author)

Biodiversity in intertidal rock pools: informing engineering criteria for artificial habitat enhancement in the built environment.

Science.gov (United States)

Firth, Louise B; Schofield, Meredith; White, Freya J; Skov, Martin W; Hawkins, Stephen J

2014-12-01

Coastal defence structures are proliferating to counter rising and stormier seas. With increasing concern about the ecological value of built environments, efforts are being made to create novel habitat to increase biodiversity. Rock pools are infrequent on artificial structures. We compared biodiversity patterns between rock pools and emergent rock and assessed the role of pool depth and substratum incline in determining patterns of biodiversity. Rock pools were more taxon rich than emergent substrata. Patterns varied with depth and incline with algal groups being more positively associated with shallow than deeper habitats. Substratum incline had little influence on colonising epibiota, with the exception of canopy algae in deeper habitats where vertical surfaces supported greater taxon richness than horizontal surfaces. The creation of artificial rock pools in built environments will have a positive effect on biodiversity. Building pools of varying depths and inclines and shore heights will provide a range of habitats, increase environmental heterogeneity, therefore creating more possible ecological niches, promoting local biodiversity. Copyright © 2014 Elsevier Ltd. All rights reserved.

Integration of rock physical signatures with depositional environments: A case study from East Coast of India

Science.gov (United States)

Mondal, Samit; Yadav, Ashok; Chatterjee, Rima

2018-01-01

Rock physical crossplots from different geological setup along eastern continental margin of India (ECMI) represent diversified signatures. To characterize the reservoirs in rock physics domain (velocity/modulus versus porosity) and then connecting the interpretation with geological model has been the objectives of the present study. Petrophysical logs (total porosity and volume of shale) from five wells located at sedimentary basins of ECMI have been analyzed to quantify the types of shale such as: laminated, dispersed and structural in reservoir. Presence of various shale types belonging to different depositional environments is coupled to define distinct rock physical crossplot trends for different geological setup. Wells from three different basins in East Coast of India have been used to capture diversity in depositional environments. Contact model theory has been applied to the crossplot to examine the change in rock velocity with change in reservoir properties like porosity and volume of shale. The depositional and diagenetic trends have been shown in the crossplot to showcase the prime controlling factor which reduces the reservoir porosity. Apart from that, the effect of geological factors like effective stress, sorting, packing, grain size uniformity on reservoir properties have also been focused. The rock physical signatures for distinct depositional environments, effect of crucial geological factors on crossplot trends coupled with established sedimentological models in drilled area are investigated to reduce the uncertainties in reservoir characterization for undrilled potentials.

Measurements of cutter forces and cutter temperature of boring machine in Aespoe Hard Rock Laboratory

Energy Technology Data Exchange (ETDEWEB)

Zhang, Z.X.; Kou, S.Q.; Lindqvist, P.-A. [Luleaa Univ. of Technology (Sweden)

2001-04-01

This report presents both the testing methods used and the testing results obtained for cutter forces and cutter temperature during field boring in Aespoe Hard Rock Laboratory. In order to estimate the strains induced by cutter forces in the cutter shaft and choose proper transducers, first a numerical simulation was performed. The simulation results indicated that the cutter forces should be measurable by ordinary strain gauges. Furthermore, an independent three-direction loading system for laboratory calibration was set up to solve force-coupling problems appearing in field measurements. By means of the established measuring system, which was proved successfully in the laboratory, the normal forces, tangential forces, and side forces of two button cutters in the boring machine were measured in the field. In addition, the temperature in the shaft of the front cutter was measured. After the measurements of the cutter forces and cutter temperature, rock core samples were taken from the bottom and the wall of the testing borehole. Then the samples were cut, polished, and examined by means of the Scanning Electron Microscope (SEM). After that, the lengths of major cracks induced by the cutters in the rock samples were measured, and an approximate relationship between the length of the medium cracks and the relevant cutter forces was obtained. This relationship was compared with the theoretical relationship established before. Finally, according to the measured results, the cracked zones around the borehole were described. The results show that: (1) there are two kinds of cracked zones: one in the borehole wall and the other in the bottom of the borehole. The depth of the cracked zone in the borehole bottom is much larger than that in the borehole wall because the maximum normal force of the front cutter is always much larger than that of the gauge cutter. (2) Each cracked zone includes a densely cracked zone and all the longest medium cracks caused by mechanical

Using DC electrical resistivity tomography to quantify preferential flow in fractured rock environments

CSIR Research Space (South Africa)

May, F

2011-09-01

Full Text Available . This investigation aims to identify preferential flow paths in fractured rock environments. Time-lapse Electrical Resistivity Tomography (TLERT, Lund Imaging System), is regarded as a suitable method for identifying preferential water flow....

The Aespoe Hard Rock Laboratory: Final evaluation of the hydrogeochemical pre-investigations in relation to existing geologic and hydraulic conditions

International Nuclear Information System (INIS)

Smellie, J.; Laaksoharju, M.

1992-11-01

The Swedish Nuclear Fuel and Management Company (SKB) is currently excavating the access tunnel to an underground experimental laboratory, the Aespoe Hard Rock Laboratory, planned to be located some 500 m below the island of Aespoe which is located in the Simpevarp area, southeast Sweden. The construction of an underground laboratory forms part of the overall SKB strategy to test, not only the construction techniques for deep excavation, but also the various methods and protocols required to obtain a three-dimensional model of the geology and groundwater flow and chemistry, within a fractured crystalline bedrock similar to that envisaged for the final disposal of spent fuel. Aespoe was chosen because it geologically represents a variety of typical crystalline bedrock environments. The hydrogeochemical activities described and interpreted in this report form part of the initial pre-investigation phase (from the surface to around 1000 metres depth) aimed at siting the laboratory, describing the natural hydrogeological and hydrogeochemical conditions in the bedrock and predicting the changes that will occur during excavation and construction of the laboratory. Hydrogeochemical interpretation has therefore been closely integrated with the hydrogeological investigations and other disciplines of major influence, in particular, bedrock geology and geochemistry and fracture mineralogy and chemistry. A large section of this report has been devoted to the detailed investigation of each individual zone hydraulically selected, tested and sampled for hydrogeochemical characterization. The data have been used to describe the chemistry and origin of the Aespoe groundwaters, models have been developed to illustrate groundwater mixing and standard geochemical modelling approaches have been employed to understand rock/water interaction processes. An attempt has been made to integrate the hydrogeochemical information with known geological and hydrogeological parameters to construct a

Effects of cutting parameters and machining environments on surface roughness in hard turning using design of experiment

Science.gov (United States)

Mia, Mozammel; Bashir, Mahmood Al; Dhar, Nikhil Ranjan

2016-07-01

Hard turning is gradually replacing the time consuming conventional turning process, which is typically followed by grinding, by producing surface quality compatible to grinding. The hard turned surface roughness depends on the cutting parameters, machining environments and tool insert configurations. In this article the variation of the surface roughness of the produced surfaces with the changes in tool insert configuration, use of coolant and different cutting parameters (cutting speed, feed rate) has been investigated. This investigation was performed in machining AISI 1060 steel, hardened to 56 HRC by heat treatment, using coated carbide inserts under two different machining environments. The depth of cut, fluid pressure and material hardness were kept constant. The Design of Experiment (DOE) was performed to determine the number and combination sets of different cutting parameters. A full factorial analysis has been performed to examine the effect of main factors as well as interaction effect of factors on surface roughness. A statistical analysis of variance (ANOVA) was employed to determine the combined effect of cutting parameters, environment and tool configuration. The result of this analysis reveals that environment has the most significant impact on surface roughness followed by feed rate and tool configuration respectively.

Aespoe Hard Rock Laboratory. Annual Report 2002

International Nuclear Information System (INIS)

2003-06-01

The Aespoe HRL was opened in 1994 as a research centre and underground laboratory. The experiments performed in Aespoe HRL are related to the rock, its properties, and in situ environmental conditions. Tests of models for groundwater flow, radionuclide migration and chemical/biological processes are some of the main purposes of the Aespoe HRL. The programme includes projects with the aim to evaluate the usefulness and reliability of different models and to develop and test methods for determination of parameters required as input to conceptual and numerical models. The retardation in rock is studied at different experiment scales in a programme called Tracer Retention Understanding Experiments (TRUE). The Long Term Diffusion Experiment constitutes a complement to performed diffusion and sorption laboratory experiments, and is a natural extension of the experiments conducted as part of the TRUE experiments. Radionuclide retention experiments are carried out with the aim to confirm result from laboratory experiments in situ, where conditions representative for the properties of groundwater at repository depth prevail. In CHEMLAB 1 two kinds of experiments to study the influence of radiolysis on the mobility of technetium in bentonite were started in the end of 2002. Experiments to study migration of actinides in natural fractures in drill cores are being carried out in CHELMAB 2. The findings of potential transport of solutes by colloids and access to more sensitive instruments for colloid measurements motivated a Colloid Project at Aespoe HRL. There are presently four specific microbial process areas identified that are of importance for proper repository functions and that are studied in the Microbe Project. The process areas are; biomobilisation of radionuclides, bioimmobilisation of radionuclides, microbial effects on the chemical stability, and microbial corrosion of copper. The main objectives of the Matrix Fluid Chemistry experiment are to understand the

Aespoe Hard Rock Laboratory. Annual Report 2002

Energy Technology Data Exchange (ETDEWEB)

NONE

2003-06-01

The Aespoe HRL was opened in 1994 as a research centre and underground laboratory. The experiments performed in Aespoe HRL are related to the rock, its properties, and in situ environmental conditions. Tests of models for groundwater flow, radionuclide migration and chemical/biological processes are some of the main purposes of the Aespoe HRL. The programme includes projects with the aim to evaluate the usefulness and reliability of different models and to develop and test methods for determination of parameters required as input to conceptual and numerical models. The retardation in rock is studied at different experiment scales in a programme called Tracer Retention Understanding Experiments (TRUE). The Long Term Diffusion Experiment constitutes a complement to performed diffusion and sorption laboratory experiments, and is a natural extension of the experiments conducted as part of the TRUE experiments. Radionuclide retention experiments are carried out with the aim to confirm result from laboratory experiments in situ, where conditions representative for the properties of groundwater at repository depth prevail. In CHEMLAB 1 two kinds of experiments to study the influence of radiolysis on the mobility of technetium in bentonite were started in the end of 2002. Experiments to study migration of actinides in natural fractures in drill cores are being carried out in CHELMAB 2. The findings of potential transport of solutes by colloids and access to more sensitive instruments for colloid measurements motivated a Colloid Project at Aespoe HRL. There are presently four specific microbial process areas identified that are of importance for proper repository functions and that are studied in the Microbe Project. The process areas are; biomobilisation of radionuclides, bioimmobilisation of radionuclides, microbial effects on the chemical stability, and microbial corrosion of copper. The main objectives of the Matrix Fluid Chemistry experiment are to understand the

The Spatial Assessment of the Current Seismic Hazard State for Hard Rock Underground Mines

Science.gov (United States)

Wesseloo, Johan

2018-06-01

Mining-induced seismic hazard assessment is an important component in the management of safety and financial risk in mines. As the seismic hazard is a response to the mining activity, it is non-stationary and variable both in space and time. This paper presents an approach for implementing a probabilistic seismic hazard assessment to assess the current hazard state of a mine. Each of the components of the probabilistic seismic hazard assessment is considered within the context of hard rock underground mines. The focus of this paper is the assessment of the in-mine hazard distribution and does not consider the hazard to nearby public or structures. A rating system and methodologies to present hazard maps, for the purpose of communicating to different stakeholders in the mine, i.e. mine managers, technical personnel and the work force, are developed. The approach allows one to update the assessment with relative ease and within short time periods as new data become available, enabling the monitoring of the spatial and temporal change in the seismic hazard.

Thermal effects in disposal of radioactive waste in hard rock

International Nuclear Information System (INIS)

Bourke, P.J.; Hodgkinson, D.P.; Batchelor, A.S.

1978-01-01

The first objective of the UKAEA programme of field heating experiments is to study any variations in thermal conductivity of granite over long (10 - 100m) distances heated to high (100's 0 C) temperatures for about a year. A description is given of the first tests with an 18 kW heater at 50 m depth and 72 thermocouples in the surrounding 25m radius sphere of rock. The reasons for choice of this scale of experiment are presented and the problems encountered and initial results are described. The further objectives of these experiments are to investigate thermal stresses and any cracking of the granite so that thermally induced movement of water through rock with both its natural and any increased permeability can be quantified. Measurements to be made of the mechanical and permeable properties as the rock heats are described

Ore-forming environment and ore-forming system of carbonaceous-siliceous-pelitic rock type uranium deposit in China

International Nuclear Information System (INIS)

Qi Fucheng; Zhang Zilong; Li Zhixing; He Zhongbo; Wang Wenquan

2012-01-01

It is proposed that there are four types of ore-forming systems about carbonaceous-siliceous-pelitic rock type uranium deposit in China based on systematic study on structural environment and distribution regularity of uraniferous construction of marine carbonaceous-siliceous-pelitic rock in China: continental margin rift valley ore-forming systems, continental margin rifting deep fracture zone ore-forming systems, landmass boundary borderland basin ore-forming systems and epicontinental mobile belt downfaulted aulacogen ore-forming systems. It is propounded definitely that it is controlled by margin rift valley ore-forming systems and continental margin rifting deep fracture zone ore-forming systems for large-scale uranium mineralization of carbonaceous-siliceous-pelitic rock type uranium deposit in China, which is also controlled by uraniferous marine carbonaceous-siliceous-pelitic rock construction made up of silicalite, siliceous phosphorite and carbonaceous-siliceous-pelitic rock, which settled down accompany with submarine backwash and sub marine volcanic eruption in margin rift valley and continental margin rifting mineralizing environment. Continental mar gin rift valley and continental margin rifting thermal sedimentation or exhalation sedimentation is the mechanism of forming large-scale uraniferous marine carbonaceous-siliceous-pelitic rock construction Early Palaeozoic Era in China or large-scale uranium-polymetallic mineralization. (authors)

Processes and mechanisms governing hard rock cliff erosion in western Brittany, France

Science.gov (United States)

Laute, Katja; Letortu, Pauline; Le Dantec, Nicolas

2017-04-01

The evolution of rocky coasts is controlled by the interplay between subaerial, marine as well as biological processes, and the geological context. In times of ongoing climate change it is difficult to predict how these erosional landscapes will respond for example to anticipated sea-level rise or to an increase in storminess. However, it can be expected that changes in the morphodynamics of rocky coasts will have a noticeable effect on society and infrastructure. Recent studies have proven that monitoring cliff micro-seismic ground motion has been very effective in exploring both marine and atmospheric actions on coastal cliffs. But only few studies have focused so far on the effects of wave loading and water circulation (runoff, infiltration, water table variations) on cliff stability and subsequent erosion, considering the interaction between subaerial and marine processes. This project focuses on the identification and quantification of environmental controls on hard rock cliff erosion with an emphasis on discriminating the relative contributions of subaerial and marine processes. We aim at relating different sources of mechanical stress (e.g. wave loading, direct wave impact, hydrostatic pressure, thermal expansion) to cliff-scale strain (cliff-top swaying and shaking) and micro-fracturing (generation, expansion and contraction of micro-cracks) with the objective to unravel and discriminate triggering mechanisms of cliff failure. A four-month monitoring field experiment during the winter period (February-May) of 2017 is carried out at a cliff face located in Porsmilin beach (western Brittany, France). The selected cliff section is exposed to Atlantic swell from the south/southwest with a significant wave height of ca. 1.5 m on average and, reaching up to 4 m during storm events. The cliff rises ca. 20 m above the beach and is mainly formed of orthogneiss with intrusions of granodiorite. The entire cliff is highly fractured and altered, which can promote slope

Hard-rock tunneling using pulsed electron beams

International Nuclear Information System (INIS)

Avery, R.T.; Keefe, D.; Brekke, T.L.; Finnie, I.

1975-01-01

Intense sub-microsecond bursts of energetic electrons cause significant pulverization and surface spalling of a variety of rock types. The spall debris generally consists of sand, dust, and small flakes. If carried out at rapid repetition rate, this technique appears promising for increasing the speed and reducing the cost of underground excavation of tunnels, mines, and storage spaces. The conceptual design features of a pulsed electron tunnel excavator, capable of tunneling approximately ten times faster than conventional drill/blast methods, is presented. (auth)

Molluscan assemblages on coral reefs and associated hard substrata in the northern Red Sea

Science.gov (United States)

Zuschin, M.; Hohenegger, J.; Steininger, F.

2001-09-01

Information on spatial variability and distribution patterns of organisms in coral reef environments is necessary to evaluate the increasing anthropogenic disturbance of marine environments (Richmond 1993; Wilkinson 1993; Dayton 1994). Therefore different types of subtidal, reef-associated hard substrata (reef flats, reef slopes, coral carpets, coral patches, rock grounds), each with different coral associations, were investigated to determine the distribution pattern of molluscs and their life habits (feeding strategies and substrate relations). The molluscs were strongly dominated by taxa with distinct relations to corals, and five assemblages were differentiated. The Dendropoma maxima assemblage on reef flats is a discrete entity, strongly dominated by this encrusting and suspension-feeding gastropod. All other assemblages are arranged along a substrate gradient of changing coral associations and potential molluscan habitats. The Coralliophila neritoidea- Barbatia foliata assemblage depends on the presence of Porites and shows a dominance of gastropods feeding on corals and of bivalves associated with living corals. The Chamoidea- Cerithium spp. assemblage on rock grounds is strongly dominated by encrusting bivalves. The Drupella cornus-Pteriidae assemblage occurs on Millepora- Acropora reef slopes and is strongly dominated by bivalves associated with living corals. The Barbatia setigera- Ctenoides annulata assemblage includes a broad variety of taxa, molluscan life habits and bottom types, but occurs mainly on faviid carpets and is transitional among the other three assemblages. A predicted degradation of coral coverage to rock bottoms due to increasing eutrophication and physical damage in the study area (Riegl and Piller 2000) will result in a loss of coral-associated molluscs in favor of bivalve crevice dwellers in dead coral heads and of encrusters on dead hard substrata.

A sampling study on rock properties affecting drilling rate index (DRI)

Science.gov (United States)

Yenice, Hayati; Özdoğan, Mehmet V.; Özfırat, M. Kemal

2018-05-01

Drilling rate index (DRI) developed in Norway is a very useful index in determining the drillability of rocks and even in performance prediction of hard rock TBMs and it requires special laboratory test equipment. Drillability is one of the most important subjects in rock excavation. However, determining drillability index from physical and mechanical properties of rocks is very important for practicing engineers such as underground excavation, drilling operations in open pit mining, underground mining and natural stone production. That is why many researchers have studied concerned with drillability to find the correlations between drilling rate index (DRI) and penetration rate, influence of geological properties on drillability prediction in tunneling, correlations between rock properties and drillability. In this study, the relationships between drilling rate index (DRI) and some physico-mechanical properties (Density, Shore hardness, uniaxial compressive strength (UCS, σc), Indirect tensile strength (ITS, σt)) of three different rock groups including magmatic, sedimentary and metamorphic were evaluated using both simple and multiple regression analysis. This study reveals the effects of rock properties on DRI according to different types of rocks. In simple regression, quite high correlations were found between DRI and uniaxial compressive strength (UCS) and also between DRI and indirect tensile strength (ITS) values. Multiple regression analyses revealed even higher correlations when compared to simple regression. Especially, UCS, ITS, Shore hardness (SH) and the interactions between them were found to be very effective on DRI values.

Hard rock tunneling using pulsed electron beams

International Nuclear Information System (INIS)

Avery, R.T.; Brekke, T.L.; Finnie, I.

1974-01-01

Intense submicrosecond bursts of energetic electrons cause significant pulverization and surface spalling of a variety of rock types, the spall debris generally consisting of sand, dust, and small flakes. If carried out at rapid repetition rate this can lead to a promising technique for increasing the speed and reducing the cost of underground excavation of tunnels, mines, and storage spaces. The conceptual design features of a Pulsed Electron Tunnel Excavator capable of tunneling approximately ten times faster than conventional drill/blast methods were studied. (auth)

Mechanisms controlling rock coast evolution in paraglacial landscapes - examples from Arctic, Antarctic and Scandinavian regions

Science.gov (United States)

Strzelecki, M. C.; Lim, M.; Kasprzek, M.; Swirad, Z. M.; Rachlewicz, G.; Migoń, P.; Pawlowski, L.; Jaskolski, M.

2017-12-01

This paper presents the results of an investigation into the processes controlling development of paraglacial rock coast systems in Hornsund, Svalbard, Admiralty Bay, South Shetland Islands and Gotland Island, Scandinavia. A suite of nested geomorphological and geophysical methods have been applied to characterize the functioning of rock cliffs, shore platforms and stacks influenced by lithological control and geomorphic processes driven by paraglacial coast environments - both in glaciated and deglaciated study sites. Rock hardness, quantified by Schmidt hammer rebound tests, demonstrate strong spatial control on the degree of rock weathering (rock strength) along studied rock coasts. Elevation controlled geomorphic zones are identified and linked to distinct processes and mechanisms, transitioning from peak hardness values at the icefoot/sea-ice through the wave and storm dominated scour zones to the lowest values on the cliff tops, where the effects of periglacial weathering dominate. Observations of rock surface change using a traversing micro-erosion meter (TMEM) indicate that significant changes in erosion rates occur at the junction between shore platform and the cliff toe, where rock erosion is facilitated by frequent wetting and drying and operation of nivation and sea ice processes (formation and melting of snow patches and icefoot complexes). Electrical resistivity tomography (ERT) surveys have been used to investigate frozen ground control on rock coast dynamics and reveal the strong interaction with marine processes in polar coastal settings. In Gotland, Scandinavia the morphology of rocky coastal landforms (rauks) bear traces of numerous environmental changes that occurred in Baltic region over the Holocene including salinity, temperature, ice-cover/storminess and relative sea-level. The results are synthesised to propose a new conceptual model of paraglacial rock coast systems, with the aim of contributing towards a unifying concept of cold region

A self propelled drilling system for hard-rock, horizontal and coiled tube drilling

Energy Technology Data Exchange (ETDEWEB)

Biglin, D.; Wassell, M.

1997-12-31

Several advancements are needed to improve the efficiency and reliability of both hard rock drilling and extended reach drilling. This paper will present a Self Propelled Drilling System (SPDS) which can grip the borehole wall in order to provide a stable platform for the application of weight on bit (WOB) and resisting the reactive torque created by the downhole drilling motor, bit and formation interaction. The system will also dampen the damaging effects of drill string vibration. This tool employs two hydraulically activated anchors (front and rear) to grip the borehole wall, and a two-way thrust mandrel to apply both the drilling force to the bit, and a retraction force to pull the drill string into the hole. Forward drilling motion will commence by sequencing the anchor pistons and thrust mandrel to allow the tool to walk in a stepping motion. The SPDS has a microprocessor to control valve timing, sensing and communication functions. An optional Measurement While Drilling (MWD) interface can provide two-way communication of critical operating parameters such as hydraulic pressure and piston location. This information can then be telemetered to the surface, or used downhole to autonomously control system parameters such as anchor and thrust force or damping characteristics.

Mechanism of Rock Burst Occurrence in Specially Thick Coal Seam with Rock Parting

Science.gov (United States)

Wang, Jian-chao; Jiang, Fu-xing; Meng, Xiang-jun; Wang, Xu-you; Zhu, Si-tao; Feng, Yu

2016-05-01

Specially thick coal seam with complex construction, such as rock parting and alternative soft and hard coal, is called specially thick coal seam with rock parting (STCSRP), which easily leads to rock burst during mining. Based on the stress distribution of rock parting zone, this study investigated the mechanism, engineering discriminant conditions, prevention methods, and risk evaluation method of rock burst occurrence in STCSRP through setting up a mechanical model. The main conclusions of this study are as follows. (1) When the mining face moves closer to the rock parting zone, the original non-uniform stress of the rock parting zone and the advancing stress of the mining face are combined to intensify gradually the shearing action of coal near the mining face. When the shearing action reaches a certain degree, rock burst easily occurs near the mining face. (2) Rock burst occurrence in STCSRP is positively associated with mining depth, advancing stress concentration factor of the mining face, thickness of rock parting, bursting liability of coal, thickness ratio of rock parting to coal seam, and difference of elastic modulus between rock parting and coal, whereas negatively associated with shear strength. (3) Technologies of large-diameter drilling, coal seam water injection, and deep hole blasting can reduce advancing stress concentration factor, thickness of rock parting, and difference of elastic modulus between rock parting and coal to lower the risk of rock burst in STCSRP. (4) The research result was applied to evaluate and control the risk of rock burst occurrence in STCSRP.

Service-Oriented Architecture (SOA) Instantiation within a Hard Real-Time, Deterministic Combat System Environment

Science.gov (United States)

Moreland, James D., Jr

2013-01-01

This research investigates the instantiation of a Service-Oriented Architecture (SOA) within a hard real-time (stringent time constraints), deterministic (maximum predictability) combat system (CS) environment. There are numerous stakeholders across the U.S. Department of the Navy who are affected by this development, and therefore the system…

State-of-the-Art Report for the Deep URL Facility Development : Aspo Hard Rock Laboratory, Grimsel Test Site

International Nuclear Information System (INIS)

Kim, Kyung Su; Bae, Dae Seok; Kim, Geon Young

2012-01-01

This report analysed the development status on the SKB's Hard Rock Laboratory and Nagra's Grimsel Test Site facilities to investigate their facility overview, operation system, site condition, project history and procedure, and current experiment programmes of underground research laboratory. SKB and Nagra had launched high level radioactive waste disposal project around 1970's. Actual site investigation activities were initiated since 1990's and the time schedule for siting programmes to determine the final disposal site were taken fifteen to thirty years. Furthermore, ten to twenty years will be needed to site characterization, facility design, construction, and operation commissioning. Nagra had constructed Grimsel Test Site facility in southern Switzerland Apls with the collaboration of KWO electrical company in early 1980's. This facility is characterized of a centre of excellence for underground Research and Development (R and D) to support projects for the disposal of radioactive and chemo-toxic waste and not a potential repository site. The SKB's Aspo HRL constructed in outside Oskarshamn is a unique PBG-URL facility. SKB is conducting full-scale research and development here in preparation for the construction of a final repository for spent nuclear fuel. The research programmes for the development of disposal technologies is performed over thirty to fifty years prior to repository operation. In 2000's, research on long-term phenomena, i.e., optimization of disposal concept, understanding of coupling process, validation of mathematical model, test and development of safety assessment models, characterization of deep geochemical environment, and long-term demonstration experiments have been leading the issues of research and development

Structural and neural network analyses of fracture systems at the Aespoe Hard Rock Laboratory, SE Sweden

International Nuclear Information System (INIS)

Sirat, M.

1999-01-01

The > 10,000 fractures documented in the 450 m deep Aespoe Hard Rock Laboratory (HRL) provide a unique opportunity to study brittle deformation of a Swedish bedrock mass. The fracture population consists of six major sets, one sub-horizontal and five sub-vertical. A classical structural analysis explored the interrelations between geometry and frequency of both dry and wet fractures with respect to depth and in-situ stresses. Three main findings are: In-situ stresses govern frequency distributions of dilated, hence water-bearing fractures. About 68.5% of sub-horizontal fractures are dilated in the thrust regime above a depth of ca. 230 m while 53% of sub-vertical fractures are dilated in the underlying wrench regime. Fractures curve both horizontally and vertically, a finding confirmed by the application of artificial neural networks that included Back-Propagation and Self-Organizing (Kohonen) networks. The asymmetry of the total fracture population and tilts of the sub-Cambrian peneplain demonstrates that multiple reactivations of fractures have tilted the Aespoe rock mass 6 deg to the west. The potential space problem raised by this tilt is negated by systematic curvature of steep fractures, some of which sole out to gently dipping fracture zones. Fractures probably developed their curvature when they formed deep in crystalline crust in Precambrian times but have since reactivated at shallow depths. These findings add significantly to the conceptual model of Aespoe and should be taken into account in future studies regarding the isolation of Sweden's high-grade radioactive waste in crystalline bedrock

Hydrofracturing water boreholes in hard rock aquifers in Scotland

CSIR Research Space (South Africa)

Cobbing, J

2007-01-01

Full Text Available rural areas of the UK, low-productivity aquifers are an important resource for small public water supplies. Where a borehole in low-productivity crystalline rocks proves too low yielding for its designed purpose, hydrofracturing is a cost-effective means...

Microwave propagation and absorption and its thermo-mechanical consequences in heterogeneous rocks.

Science.gov (United States)

Meisels, R; Toifl, M; Hartlieb, P; Kuchar, F; Antretter, T

2015-02-10

A numerical analysis in a two-component model rock is presented including the propagation and absorption of a microwave beam as well as the microwave-induced temperature and stress distributions in a consistent way. The analyses are two-dimensional and consider absorbing inclusions (discs) in a non-absorbing matrix representing the model of a heterogeneous rock. The microwave analysis (finite difference time domain - FDTD) is performed with values of the dielectric permittivity typical for hard rocks. Reflections at the discs/matrix interfaces and absorption in the discs lead to diffuse scattering with up to 20% changes of the intensity in the main beam compared to a homogeneous model rock. The subsequent thermo-mechanical finite element (FE) analysis indicates that the stresses become large enough to initiate damage. The results are supported by preliminary experiments on hard rock performed at 2.45 GHz.

Aespoe Hard Rock Laboratory. Annual report 1996

International Nuclear Information System (INIS)

1997-04-01

The Aespoe HRL has been constructed as part of the preparations for the deep geological repository for spent nuclear fuel in Sweden. Geoscientific investigations on Aespoe and nearby islands began 1986. Since then, bedrock conditions have been investigated by several deep boreholes. The Aespoe research village has been built and extensive underground construction work has been undertaken in parallel with comprehensive research. This has resulted in a thorough test of methods for investigation and evaluation of bedrock conditions for construction of a deep repository. The objective of the ZEDEX project is to compare the mechanical disturbance to the rock for excavation by tunnel boring and blasting. The results indicate that the role of the EDZ as a preferential pathway to radionuclide transport is limited to the damaged zone. The tracer retention understanding experiments are made to gain a better understanding of radionuclide retention in the rock and create confidence in the radionuclide transport models. During 1996 a series of tracer experiments in radially converging and dipole flow configuration have been performed. A special borehole probe has been designed for different kinds of retention experiments where data can be obtained representative for the in situ properties of groundwater at repository depth. The prototype repository test is focused on testing and demonstrating repository system function, and includes backfill and plug tests and demonstration of methods for deposition and retrieval of canisters in a new tunnel at the 420 m level. The long term tests of buffer material aim to validate models of buffer performance and at quantifying clay buffer alteration processes at adverse conditions. 80 refs, 53 figs, 16 tabs

Aespoe Hard Rock Laboratory. Annual report 1996

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-04-01

The Aespoe HRL has been constructed as part of the preparations for the deep geological repository for spent nuclear fuel in Sweden. Geoscientific investigations on Aespoe and nearby islands began 1986. Since then, bedrock conditions have been investigated by several deep boreholes. The Aespoe research village has been built and extensive underground construction work has been undertaken in parallel with comprehensive research. This has resulted in a thorough test of methods for investigation and evaluation of bedrock conditions for construction of a deep repository. The objective of the ZEDEX project is to compare the mechanical disturbance to the rock for excavation by tunnel boring and blasting. The results indicate that the role of the EDZ as a preferential pathway to radionuclide transport is limited to the damaged zone. The tracer retention understanding experiments are made to gain a better understanding of radionuclide retention in the rock and create confidence in the radionuclide transport models. During 1996 a series of tracer experiments in radially converging and dipole flow configuration have been performed. A special borehole probe has been designed for different kinds of retention experiments where data can be obtained representative for the in situ properties of groundwater at repository depth. The prototype repository test is focused on testing and demonstrating repository system function, and includes backfill and plug tests and demonstration of methods for deposition and retrieval of canisters in a new tunnel at the 420 m level. The long term tests of buffer material aim to validate models of buffer performance and at quantifying clay buffer alteration processes at adverse conditions. 80 refs, 53 figs, 16 tabs.

Innovaciones tecnológicas en la atención al cliente: Ushuaïa Ibiza Beach Hotel y Hard Rock Hotel Ibiza

OpenAIRE

Ramón Cardona, José; Jiménez Caballero, José Luis (Coordinador)

2016-01-01

Palladium Hotel Group es la octava cadena hotelera de España y ha centrado sus objetivos en generar valor añadido para los clientes, siendo la experiencia emocional la línea central de su producto. El Ushuaïa Ibiza Beach Hotel y el Hard Rock Hotel Ibiza han sido el campo de pruebas de varias innovaciones tecnológicas para la atención al cliente: integración de las redes sociales en la experiencia del cliente (Social Presence); implantación de tecnología biométrica; uso de ...

Aespoe Hard Rock Laboratory. Sensor Data Report No 23

Energy Technology Data Exchange (ETDEWEB)

Goudarzi, Reza; Johannesson, Lars-Erik (Clay Technology AB (Sweden))

2010-11-15

The Prototype Repository Test consists of two sections. The installation of the first Section of Prototype Repository was made during summer and autumn 2001 and Section 2 was installed in spring and summer 2003. This report presents data from measurements in the Prototype Repository during the period 20010917-20100601. The report is organized so that the actual measured results are shown in Appendix 1-10, where Appendix 8 deals with measurements of canister displacements (by AITEMIN), Appendix 9 deals with geo-electric measurements in the backfill (by GRS), Appendix 10 deals with stress and strain measurement in the rock (by AaF) and Appendix 11 deals with measurement of water pressure in the rock (by VBB/VIAK). The main report and Appendix 1-7 deal with the rest of the measurements. Section 1. The following measurements are made in the bentonite in each of the two instrumented deposition holes in Section 1 (1 and 3): Temperature is measured in 32 points, total pressure in 27 points, pore water pressure in 14 points and relative humidity in 37 points. Temperature is also measured by all relative humidity gauges. Every measuring point is related to a local coordinate system in the deposition hole. The following measurements are made in the backfill in Section 1. Temperature is measured in 20 points, total pressure in 18 points, pore water pressure in 23 points and relative humidity in 45 points. Temperature is also measured by all relative humidity gauges. Furthermore, water content is measured by an electric chain in one section. Every measuring point is related to a local coordinate system in the tunnel. The following measurements are made on the surface of the canisters in Section 1: Temperature is measured every meter along two fiber optic cables. Furthermore, displacements of the canister in hole 3 are measured with 6 gauges. The following measurements are made in the rock in Section 1: Temperature is measured in 37 points in boreholes in the floor. Water

DEPOSITIONAL ENVIRONMENT AND ORGANIC GEOCHEMICAL CHARACTERISTICS OF LOWER EOCENE BITUMINOUS ROCKS, IN THE KÜRNÜÇ/GÖYNÜK-BOLU AREA

Directory of Open Access Journals (Sweden)

Ali SARI

2016-12-01

Full Text Available In this study, dark gray and dark brown colored, organic-carbon rich bituminous rocks (bituminous marl and bituminous shale exposing around the Kürnüç area (Göynük, Bolu are investigated by means of or- ganic geochemical characteristics. In this respect, rock lithologies, depositional environments, rock source potential, kerogen and organic maturity types and hydrocarbon generation potentials of bituminous rocks were determined. For this reason, pyrolysis (Rock Eval–VI analysis, gas chromatography (GC and gas chromatography-mass spectrometer (GC-MS analyses were carried out. In addition, spore color index (SCI was determined with organic petrographic method and stable carbon analysis (δ13C of the samples were also conducted. Lithology of the studied samples is of clastic source and the depositional environ- ment is a lagoon with a partial connection to the sea. In bituminous rocks with excellent source rock potential TOC values are in the range of 2.52-8.38 wt % (average 6.08 wt %. With the exception of two samples (Type II kerogen type of all samples is Type I. According to pyrolysis, GC and GC-MS organic maturity results, all the samples are in immature stage. Organic geochemical data indicate that bituminous rocks have an excellent oil generation potential and there is no organic contamination.

Aespoe Hard Rock Laboratory. Sensor Data Report No 23

International Nuclear Information System (INIS)

Goudarzi, Reza; Johannesson, Lars-Erik

2010-11-01

The Prototype Repository Test consists of two sections. The installation of the first Section of Prototype Repository was made during summer and autumn 2001 and Section 2 was installed in spring and summer 2003. This report presents data from measurements in the Prototype Repository during the period 20010917-20100601. The report is organized so that the actual measured results are shown in Appendix 1-10, where Appendix 8 deals with measurements of canister displacements (by AITEMIN), Appendix 9 deals with geo-electric measurements in the backfill (by GRS), Appendix 10 deals with stress and strain measurement in the rock (by AaF) and Appendix 11 deals with measurement of water pressure in the rock (by VBB/VIAK). The main report and Appendix 1-7 deal with the rest of the measurements. Section 1. The following measurements are made in the bentonite in each of the two instrumented deposition holes in Section 1 (1 and 3): Temperature is measured in 32 points, total pressure in 27 points, pore water pressure in 14 points and relative humidity in 37 points. Temperature is also measured by all relative humidity gauges. Every measuring point is related to a local coordinate system in the deposition hole. The following measurements are made in the backfill in Section 1. Temperature is measured in 20 points, total pressure in 18 points, pore water pressure in 23 points and relative humidity in 45 points. Temperature is also measured by all relative humidity gauges. Furthermore, water content is measured by an electric chain in one section. Every measuring point is related to a local coordinate system in the tunnel. The following measurements are made on the surface of the canisters in Section 1: Temperature is measured every meter along two fiber optic cables. Furthermore, displacements of the canister in hole 3 are measured with 6 gauges. The following measurements are made in the rock in Section 1: Temperature is measured in 37 points in boreholes in the floor. Water

Aespoe Hard Rock Laboratory. Evaluation of scaling records for TASA access tunnel

International Nuclear Information System (INIS)

Ittner, Henrik

2009-01-01

This report presents the result of a project accomplished during the summer 2009. It introduces a method to estimate the magnitude, mass distribution and cause of scaled blocks by tunnel mapping and evaluation of scaling data records. These issues are important for understanding the impact of the excavation method on the surrounding rock mass during excavation of the planned underground repository for spent nuclear fuel. The project includes mapping of the 3120 m drill and blast excavated part of the TASA access tunnel in the Aespoe Hard Rock Laboratory (HRL). In addition it includes development of a method for evaluation of the collected material together with scaling data records from the Site Characterization Database (SICADA). An interview has also been held with Erik Gabrielsson, who has been in charge of tunnel maintenance at Aespoe for many years. The mapping focused on to identify size and cause of areas with significant overbreaks in the tunnel roof. By distributing documented scaled volume in a tunnel section on several mapped overbreak areas in the same section it is possible to reconstruct the size of scaled blocks. The observed overbreak areas have been categorized in five different area types, depending on the cause of scaling: two geologically induced, one blast induced, one induced from a combination of geology and blasting and one unable to place in any category. For the calculated mass distribution the number of observations is declining with increasing block mass. 11% of the total blocks exceeding 400 Kg and 75% of the scaled blocks weights under 200 Kg. Most of the blocks are however lighter with 34% weighting 50 Kg or less. There is a relation between the mapped area type and the size distribution among the mapped overbreak areas. For example the areas caused by the end of blasting rounds are more frequently appearing then the other types but most of them are small in relation to the others The impression achieved from the tunnel mapping is

Aespoe Hard Rock Laboratory. Evaluation of scaling records for TASA access tunnel

Energy Technology Data Exchange (ETDEWEB)

Ittner, Henrik (Chalmers Univ. of Technology, Goeteborg (Sweden))

2009-07-01

This report presents the result of a project accomplished during the summer 2009. It introduces a method to estimate the magnitude, mass distribution and cause of scaled blocks by tunnel mapping and evaluation of scaling data records. These issues are important for understanding the impact of the excavation method on the surrounding rock mass during excavation of the planned underground repository for spent nuclear fuel. The project includes mapping of the 3120 m drill and blast excavated part of the TASA access tunnel in the Aespoe Hard Rock Laboratory (HRL). In addition it includes development of a method for evaluation of the collected material together with scaling data records from the Site Characterization Database (SICADA). An interview has also been held with Erik Gabrielsson, who has been in charge of tunnel maintenance at Aespoe for many years. The mapping focused on to identify size and cause of areas with significant overbreaks in the tunnel roof. By distributing documented scaled volume in a tunnel section on several mapped overbreak areas in the same section it is possible to reconstruct the size of scaled blocks. The observed overbreak areas have been categorized in five different area types, depending on the cause of scaling: two geologically induced, one blast induced, one induced from a combination of geology and blasting and one unable to place in any category. For the calculated mass distribution the number of observations is declining with increasing block mass. 11% of the total blocks exceeding 400 Kg and 75% of the scaled blocks weights under 200 Kg. Most of the blocks are however lighter with 34% weighting 50 Kg or less. There is a relation between the mapped area type and the size distribution among the mapped overbreak areas. For example the areas caused by the end of blasting rounds are more frequently appearing then the other types but most of them are small in relation to the others The impression achieved from the tunnel mapping is

Close encounter with the hard-discounter : A multiple-store shopping perspective on the impact of local hard-discounter entry

NARCIS (Netherlands)

Vroegrijk, M.J.J.; Gijsbrechts, E.; Campo, K.

2013-01-01

“Hard discounters” (HDs) have become a considerable force in grocery retailing. With rock-bottom prices and minimal assortments, they differ greatly from “large discounters” such as Wal-Mart, constituting complements to, rather than substitutes for, more traditional supermarkets. Therefore, the

Utilization of hard rock dust with red clay to produce roof tiles

Directory of Open Access Journals (Sweden)

Mst. Shanjida Sultana

2015-03-01

Full Text Available Utilization of rock dust to produce roof tiles and its effects on properties of tiles, mixed with red clay collected from Naogaon district of Bangladesh were investigated. After proper characterization of the raw materials, tiles were prepared with different percentages of rock dust (10-50% mixed with clay sintered from 850-1100 °C temperature. Rock dust has been found good for using as fluxing material after XRF study. The samples were tested for different properties such as water absorption, porosity, mechanical strength, linear shrinkage, and bulk density. The strength values have exceeded the minimum standard requirement for roof tiles with low water absorption in most samples. The results obtained made it possible to conclude about the possibility of producing roof tiles incorporating up to 40% of rock dust having better properties (lower water absorption 6.5%, strength value 31.97 MPa fired at 900 °C. Therefore these dust acts as a fluxing agent and reducing the sinteringtemperature of the clay material.

Towards mapping of rock walls using a UAV-mounted 2D laser scanner in GPS denied environments

Science.gov (United States)

Turner, Glen

In geotechnical engineering, the stability of rock excavations and walls is estimated by using tools that include a map of the orientations of exposed rock faces. However, measuring these orientations by using conventional methods can be time consuming, sometimes dangerous, and is limited to regions of the exposed rock that are reachable by a human. This thesis introduces a 2D, simulated, quadcopter-based rock wall mapping algorithm for GPS denied environments such as underground mines or near high walls on surface. The proposed algorithm employs techniques from the field of robotics known as simultaneous localization and mapping (SLAM) and is a step towards 3D rock wall mapping. Not only are quadcopters agile, but they can hover. This is very useful for confined spaces such as underground or near rock walls. The quadcopter requires sensors to enable self localization and mapping in dark, confined and GPS denied environments. However, these sensors are limited by the quadcopter payload and power restrictions. Because of these restrictions, a light weight 2D laser scanner is proposed. As a first step towards a 3D mapping algorithm, this thesis proposes a simplified scenario in which a simulated 1D laser range finder and 2D IMU are mounted on a quadcopter that is moving on a plane. Because the 1D laser does not provide enough information to map the 2D world from a single measurement, many measurements are combined over the trajectory of the quadcopter. Least Squares Optimization (LSO) is used to optimize the estimated trajectory and rock face for all data collected over the length of a light. Simulation results show that the mapping algorithm developed is a good first step. It shows that by combining measurements over a trajectory, the scanned rock face can be estimated using a lower-dimensional range sensor. A swathing manoeuvre is introduced as a way to promote loop closures within a short time period, thus reducing accumulated error. Some suggestions on how to

The need for sustainable technology diffusion in mining: Achieving the use of belt conveyor systems in the German hard-rock quarrying industry

Directory of Open Access Journals (Sweden)

Tobias Braun

2017-01-01

Full Text Available The movement of raw materials can be one of the most challenging tasks in open pit mining, with truck transportation representing the largest factor in mining costs and resulting in major greenhouse gas (GHG emissions. In this study, the transportation methods of bulk materials within German hard-rock open pit mines were investigated. Approximately 450 quarries were studied for their production tonnage, lease areas, mined rock type as well as mining methods and processing equipment. The results demonstrate that 90% of the operations use truck-based transportation methods, with the remainder relying partly or completely on continuous conveyor-based systems. The installation of continuous conveyors compared to trucks represents a real alternative because of reduced dead load, reduced GHG emissions and in many cases even reduced costs. Thus, for in-pit haulage in quarries sustainable technology substitutions exist that are yet to be adopted by the German quarrying industry. As this study shows, in the future the diffusion of sustainable technologies requires site champions and large-scale case studies that demonstrate their successful introduction in the mining value chain.

Creep in crystalline rock with application to high level nuclear waste repository

International Nuclear Information System (INIS)

Eloranta, P.; Simonen, A.

1992-06-01

The time-dependent strength and deformation properties of hard crystalline rock are studied. Theoretical models defining the phenomena which can effect these properties are reviewed. The time- dependent deformation of the openings in the proposed nuclear waste repository is analysed. The most important factors affecting the subcritical crack growth in crystalline rock are the stress state, the chemical environment, temperature and microstructure of the rock. There are several theoretical models for the analysis of creep and cyclic fatigue: deformation diagrams, rheological models thermodynamic models, reaction rate models, stochastic models, damage models and time-dependent safety factor model. They are defective in describing the three-axial stress condition and strength criteria. In addition, the required parameters are often too difficult to determine with adequate accuracy. Therefore these models are seldom applied in practice. The effect of microcrack- driven creep on the stability of the work shaft, the emplacement tunnel and the capsulation hole of a proposed nuclear waste repository was studied using a numerical model developed by Atomic Energy of Canada Ltd. According to the model, the microcrack driven creep progresses very slowly in good quality rock. Poor rock quality may accelerate the creep rate. The model is very sensitive to the properties of the rock and secondary stress state. The results show that creep causes no stability problems on excavations in good rock. The results overestimate the effect of the creep, because the analysis omitted the effect of support structures and backfilling

The destabilizing influence of heat flow on the geological environment during underground nuclear explosions

International Nuclear Information System (INIS)

Politikov, M.I.; Kamberov, I.M.; Krivchenko, V.F.; Lukashenko, S.N.; Solodukhin, V.P.

2001-01-01

The study has determined the fact that the processes of gas-radioactive ectoplasm intrusion from nuclear cavities in the geological environment bring the significant contribution in bosom destabilizing besides the mechanical rock destruction as affected by underground nuclear explosions. Not only heat field forming that reduces the rock resistance and increases its porosity is related to it, but also the forming, on the way, of man-caused contamination aureoles of the geological environment, including the underground water bearing horizon. Unfortunately, this problem is hardly studied, mainly for the lack of reliable apparatus and methods. Judging by the results of information search, the best way to solve the problem is not yet known. (author)

Establishment of land model at the Shika Nuclear Power Plant. Mainly, on rock board classification

International Nuclear Information System (INIS)

Katagawa, Hideki; Hashimoto, Toru; Hirano, Shuji

1999-01-01

In order to grasp engineering properties of basic land of constructions, there is rock board classification as a method to classify whole of rock board to some groups considerable to be nearly equal on its properties. Among the method, various methods in response to its aim and characteristics are devised, and for a classification to hard rock board, the Denken type rock board classification considering degree of weathering to its main element and so forth are well known. The basic rock board of the Shika Nuclear Power Plant is composed of middle and hard types of rock, and its weathering is limited to its shallow portion, most of which are held at fresh condition. For such land, a new classification standard in response to characteristics of land was established. Here were introduced on a progress to establish a new classification standard, its application results and rock board properties. (G.K.)

Aespoe Hard Rock Laboratory. Annual Report 2007

International Nuclear Information System (INIS)

2008-04-01

The main activities in the geoscientific fields have been: (1) Geology - besides mapping of rock surfaces and drill cores a feasibility study concerning geological mapping techniques is performed, (2) Hydrogeology - completion of the modelling work for the detailed hydro-structural model for the -450 m level and monitoring/storage of data in the computerised Hydro Monitoring System, (3) Geochemistry - sampling of groundwater in the yearly campaign and for specific experiments and (4) Rock Mechanics - field work to determine the stress levels at which core disking occur followed by numerical modelling. Experiments are performed to develop and test methods and models for the description of groundwater flow, radionuclide migration, and chemical conditions at repository depth. The programme includes projects which aim to determine parameter values that are required as input to the conceptual and numerical models. At Aespoe HRL, experiments are performed under the conditions that are expected to prevail at repository depth. The experiments are related to the rock, its properties and in situ environmental conditions. The aim is to provide information about the long-term function of natural and repository barriers. Experiments are performed to develop and test methods and models for the description of groundwater flow, radionuclide migration, and chemical conditions at repository depth. The programme includes projects which aim to determine parameter values that are required as input to the conceptual and numerical models. An important goal is to demonstrate technology for and the function of important parts of the repository system. This implies translation of current scientific knowledge and state-of- the-art technology into engineering practice applicable in a real repository. It is important that development, testing and demonstration of methods and procedures are conducted under realistic conditions and at an appropriate scale. A number of large-scale field

Aespoe Hard Rock Laboratory. Annual Report 2007

Energy Technology Data Exchange (ETDEWEB)

2007-04-15

The main activities in the geoscientific fields have been: (1) Geology - besides mapping of rock surfaces and drill cores a feasibility study concerning geological mapping techniques is performed, (2) Hydrogeology - completion of the modelling work for the detailed hydro-structural model for the -450 m level and monitoring/storage of data in the computerised Hydro Monitoring System, (3) Geochemistry - sampling of groundwater in the yearly campaign and for specific experiments and (4) Rock Mechanics - field work to determine the stress levels at which core disking occur followed by numerical modelling. Experiments are performed to develop and test methods and models for the description of groundwater flow, radionuclide migration, and chemical conditions at repository depth. The programme includes projects which aim to determine parameter values that are required as input to the conceptual and numerical models. At Aespoe HRL, experiments are performed under the conditions that are expected to prevail at repository depth. The experiments are related to the rock, its properties and in situ environmental conditions. The aim is to provide information about the long-term function of natural and repository barriers. Experiments are performed to develop and test methods and models for the description of groundwater flow, radionuclide migration, and chemical conditions at repository depth. The programme includes projects which aim to determine parameter values that are required as input to the conceptual and numerical models. An important goal is to demonstrate technology for and the function of important parts of the repository system. This implies translation of current scientific knowledge and state-of- the-art technology into engineering practice applicable in a real repository. It is important that development, testing and demonstration of methods and procedures are conducted under realistic conditions and at an appropriate scale. A number of large-scale field

Constitutive relationships for elastic deformation of clay rock: Data Analysis

Energy Technology Data Exchange (ETDEWEB)

Liu, H.H.; Rutqvist, J.; Birkholzer, J.T.

2011-04-15

Geological repositories have been considered a feasible option worldwide for storing high-level nuclear waste. Clay rock is one of the rock types under consideration for such purposes, because of its favorable features to prevent radionuclide transport from the repository. Coupled hydromechanical processes have an important impact on the performance of a clay repository, and establishing constitutive relationships for modeling such processes are essential. In this study, we propose several constitutive relationships for elastic deformation in indurated clay rocks based on three recently developed concepts. First, when applying Hooke's law in clay rocks, true strain (rock volume change divided by the current rock volume), rather than engineering strain (rock volume change divided by unstressed rock volume), should be used, except when the degree of deformation is very small. In the latter case, the two strains will be practically identical. Second, because of its inherent heterogeneity, clay rock can be divided into two parts, a hard part and a soft part, with the hard part subject to a relatively small degree of deformation compared with the soft part. Third, for swelling rock like clay, effective stress needs to be generalized to include an additional term resulting from the swelling process. To evaluate our theoretical development, we analyze uniaxial test data for core samples of Opalinus clay and laboratory measurements of single fractures within macro-cracked Callovo-Oxfordian argillite samples subject to both confinement and water reduced swelling. The results from this evaluation indicate that our constitutive relationships can adequately represent the data and explain the related observations.

Constitutive relationships for elastic deformation of clay rock: Data Analysis

International Nuclear Information System (INIS)

Liu, H.H.; Rutqvist, J.; Birkholzer, J.T.

2011-01-01

Geological repositories have been considered a feasible option worldwide for storing high-level nuclear waste. Clay rock is one of the rock types under consideration for such purposes, because of its favorable features to prevent radionuclide transport from the repository. Coupled hydromechanical processes have an important impact on the performance of a clay repository, and establishing constitutive relationships for modeling such processes are essential. In this study, we propose several constitutive relationships for elastic deformation in indurated clay rocks based on three recently developed concepts. First, when applying Hooke's law in clay rocks, true strain (rock volume change divided by the current rock volume), rather than engineering strain (rock volume change divided by unstressed rock volume), should be used, except when the degree of deformation is very small. In the latter case, the two strains will be practically identical. Second, because of its inherent heterogeneity, clay rock can be divided into two parts, a hard part and a soft part, with the hard part subject to a relatively small degree of deformation compared with the soft part. Third, for swelling rock like clay, effective stress needs to be generalized to include an additional term resulting from the swelling process. To evaluate our theoretical development, we analyze uniaxial test data for core samples of Opalinus clay and laboratory measurements of single fractures within macro-cracked Callovo-Oxfordian argillite samples subject to both confinement and water reduced swelling. The results from this evaluation indicate that our constitutive relationships can adequately represent the data and explain the related observations.

White Rock

Science.gov (United States)

2002-01-01

(Released 19 April 2002) The Science 'White Rock' is the unofficial name for this unusual landform which was first observed during the Mariner 9 mission in the early 1970's. As later analysis of additional data sets would show, White Rock is neither white nor dense rock. Its apparent brightness arises from the fact that the material surrounding it is so dark. Images from the Mars Global Surveyor MOC camera revealed dark sand dunes surrounding White Rock and on the floor of the troughs within it. Some of these dunes are just apparent in the THEMIS image. Although there was speculation that the material composing White Rock could be salts from an ancient dry lakebed, spectral data from the MGS TES instrument did not support this claim. Instead, the White Rock deposit may be the erosional remnant of a previously more continuous occurrence of air fall sediments, either volcanic ash or windblown dust. The THEMIS image offers new evidence for the idea that the original deposit covered a larger area. Approximately 10 kilometers to the southeast of the main deposit are some tiny knobs of similarly bright material preserved on the floor of a small crater. Given that the eolian erosion of the main White Rock deposit has produced isolated knobs at its edges, it is reasonable to suspect that the more distant outliers are the remnants of a once continuous deposit that stretched at least to this location. The fact that so little remains of the larger deposit suggests that the material is very easily eroded and simply blows away. The Story Fingers of hard, white rock seem to jut out like icy daggers across a moody Martian surface, but appearances can be deceiving. These bright, jagged features are neither white, nor icy, nor even hard and rocky! So what are they, and why are they so different from the surrounding terrain? Scientists know that you can't always trust what your eyes see alone. You have to use other kinds of science instruments to measure things that our eyes can

Electric resistivity and seismic refraction tomography: a challenging joint underwater survey at Äspö Hard Rock Laboratory

Directory of Open Access Journals (Sweden)

M. Ronczka

2017-06-01

Full Text Available Tunnelling below water passages is a challenging task in terms of planning, pre-investigation and construction. Fracture zones in the underlying bedrock lead to low rock quality and thus reduced stability. For natural reasons, they tend to be more frequent at water passages. Ground investigations that provide information on the subsurface are necessary prior to the construction phase, but these can be logistically difficult. Geophysics can help close the gaps between local point information by producing subsurface images. An approach that combines seismic refraction tomography and electrical resistivity tomography has been tested at the Äspö Hard Rock Laboratory (HRL. The aim was to detect fracture zones in a well-known but logistically challenging area from a measuring perspective. The presented surveys cover a water passage along part of a tunnel that connects surface facilities with an underground test laboratory. The tunnel is approximately 100 m below and 20 m east of the survey line and gives evidence for one major and several minor fracture zones. The geological and general test site conditions, e.g. with strong power line noise from the nearby nuclear power plant, are challenging for geophysical measurements. Co-located positions for seismic and ERT sensors and source positions are used on the 450 m underwater section of the 700 m profile. Because of a large transition zone that appeared in the ERT result and the missing coverage of the seismic data, fracture zones at the southern and northern parts of the underwater passage cannot be detected by separated inversion. Synthetic studies show that significant three-dimensional (3-D artefacts occur in the ERT model that even exceed the positioning errors of underwater electrodes. The model coverage is closely connected to the resolution and can be used to display the model uncertainty by introducing thresholds to fade-out regions of medium and low resolution. A structural

Electric resistivity and seismic refraction tomography: a challenging joint underwater survey at Äspö Hard Rock Laboratory

Science.gov (United States)

Ronczka, Mathias; Hellman, Kristofer; Günther, Thomas; Wisén, Roger; Dahlin, Torleif

2017-06-01

Tunnelling below water passages is a challenging task in terms of planning, pre-investigation and construction. Fracture zones in the underlying bedrock lead to low rock quality and thus reduced stability. For natural reasons, they tend to be more frequent at water passages. Ground investigations that provide information on the subsurface are necessary prior to the construction phase, but these can be logistically difficult. Geophysics can help close the gaps between local point information by producing subsurface images. An approach that combines seismic refraction tomography and electrical resistivity tomography has been tested at the Äspö Hard Rock Laboratory (HRL). The aim was to detect fracture zones in a well-known but logistically challenging area from a measuring perspective. The presented surveys cover a water passage along part of a tunnel that connects surface facilities with an underground test laboratory. The tunnel is approximately 100 m below and 20 m east of the survey line and gives evidence for one major and several minor fracture zones. The geological and general test site conditions, e.g. with strong power line noise from the nearby nuclear power plant, are challenging for geophysical measurements. Co-located positions for seismic and ERT sensors and source positions are used on the 450 m underwater section of the 700 m profile. Because of a large transition zone that appeared in the ERT result and the missing coverage of the seismic data, fracture zones at the southern and northern parts of the underwater passage cannot be detected by separated inversion. Synthetic studies show that significant three-dimensional (3-D) artefacts occur in the ERT model that even exceed the positioning errors of underwater electrodes. The model coverage is closely connected to the resolution and can be used to display the model uncertainty by introducing thresholds to fade-out regions of medium and low resolution. A structural coupling cooperative inversion

Selected elements of rock burst state assessment in case studies from the Silesian hard coal mines

Energy Technology Data Exchange (ETDEWEB)

Jozef Kabiesz; Janusz Makowka [Central Mining Institute, Katowice (Poland)

2009-09-15

Exploitation of coal seams in the Upper Silesian Coal Basin is conducted in complex and difficult conditions. These difficulties are connected with the occurrence of many natural mining hazards and limitations resulting from the existing in this area surface infrastructure. One of the most important problems of Polish mining is the rock burst hazard and reliable evaluation of its condition. During long-years' mining practice in Poland a comprehensive system of evaluation and control of this hazard was developed. In the paper the main aspects of rock burst hazard state evaluation will be presented, comprising: 1) rock mass inclination for rock bursts, i.e., rock strength properties investigation, comprehensive parametric evaluation of rock mass inclination for rock bursts, prognosis of seismic events induced by mining operations, methods of computer-aided modelling of stress and rock mass deformation parameters distribution, strategic rock mass classification under rock burst degrees; 2) immediate seismic and rock burst hazard state evaluation, i.e., low diameter test drilling method, seismologic and seismoacoustic method, comprehensive method of rock burst hazard state evaluation, non-standard methods of evaluation; 3) legal aspects of rock burst hazard state evaluation. Selected elements of the hazard state evaluation system are illustrated with specific practical examples of their application. 11 refs., 14 figs.

Scale of seismic and rock burst hazard in the Silesian companies in Poland

Energy Technology Data Exchange (ETDEWEB)

Renata Patynska; Jozef Kabiesz [Central Mining Institute, Katowice (Poland)

2009-09-15

Presently the seismic and rock burst hazard appears still to be important in most of hard coal mines in Poland. Recently, there was a significant increase of seismic activity of the Silesian rock massive, when compared with the previous years. In the period 1999-2008 the hard coal mines experienced 34 rock bursts. The causes of rockburst occurrence are presented based on the analysis of the rockbursts occurring in the Polish hard coal mines. The scale of the rockburst hazard has been characterized with respect to the mining and geological conditions of the existing exploitation. Of the factors influencing the state of rockburst hazard, the most essential one is considered the depth interval ranging from 600 m to 900 m. The basic factors that promote the rockburst occurrence are as follows: seismogenic strata, edges and remnants, goaf, faults, pillars and excessive paneling. 5 refs., 3 figs., 2 tabs.

The colloid investigations conducted at the Aespoe Hard Rock Laboratory during 2000-2004

Energy Technology Data Exchange (ETDEWEB)

Laaksoharju, Marcus [Geopoint AB, Stockholm (Sweden); Wold, Susanna [Royal Inst. of Tech., Stockholm (Sweden). School of Chemical Science and Engineering, Nuclear Chemistry] (eds.)

2005-12-15

In 2000, SKB decided to initiate an international colloid project at the Aespoe Hard Rock Laboratory in Sweden. The objectives of the colloid project are to: (i) study the role of bentonite as a colloid source, (ii) verify the background colloid concentration at Aespoe HRL and, (iii) investigate the potential for colloid formation/transport in natural groundwater concentrations. The experimental concepts for the colloid project are: laboratory experiments with bentonite, background field measurements of natural colloids, borehole specific bentonite colloid stability experiments and a fracture specific transport experiment. The activities concerning the laboratory experiments and background field measurements are described in this work; the other activities are ongoing or planned. The following conclusions were made: The bentonite colloid stability is strongly dependent on the groundwater ionic strength. Natural colloids are organic degradation products such as humic and fulvic acids, inorganic colloids (clay, calcite, iron hydroxide) and microbes. Microbes form few but large particles and their concentration increase with increasing organic carbon concentrations. The small organic colloids are present in very low concentrations in deep granitic groundwater. The concentrations can be rather high in shallow waters. The colloid concentration decreases with depth and salinity, since colloids are less stable in saline waters. The colloid content at Aespoe is less than 300 ppb. The colloid content at repository level is less than 50 ppb. The groundwater variability obtained in the boreholes reflects well the natural groundwater variability along the whole HRL tunnel.

The colloid investigations conducted at the Aespoe Hard Rock Laboratory during 2000-2004

International Nuclear Information System (INIS)

Laaksoharju, Marcus; Wold, Susanna

2005-12-01

In 2000, SKB decided to initiate an international colloid project at the Aespoe Hard Rock Laboratory in Sweden. The objectives of the colloid project are to: (i) study the role of bentonite as a colloid source, (ii) verify the background colloid concentration at Aespoe HRL and, (iii) investigate the potential for colloid formation/transport in natural groundwater concentrations. The experimental concepts for the colloid project are: laboratory experiments with bentonite, background field measurements of natural colloids, borehole specific bentonite colloid stability experiments and a fracture specific transport experiment. The activities concerning the laboratory experiments and background field measurements are described in this work; the other activities are ongoing or planned. The following conclusions were made: The bentonite colloid stability is strongly dependent on the groundwater ionic strength. Natural colloids are organic degradation products such as humic and fulvic acids, inorganic colloids (clay, calcite, iron hydroxide) and microbes. Microbes form few but large particles and their concentration increase with increasing organic carbon concentrations. The small organic colloids are present in very low concentrations in deep granitic groundwater. The concentrations can be rather high in shallow waters. The colloid concentration decreases with depth and salinity, since colloids are less stable in saline waters. The colloid content at Aespoe is less than 300 ppb. The colloid content at repository level is less than 50 ppb. The groundwater variability obtained in the boreholes reflects well the natural groundwater variability along the whole HRL tunnel

Study on investigation and evaluation methods of deep seated sedimentary rocks. Chemical weathering, pore water squeezing and relationships of physical properties of sedimentary rocks

International Nuclear Information System (INIS)

Oyama, Takahiro; Suzuki, Koichi

2006-01-01

Chemical weathering, porewater squeezing and physical properties for the sedimentary rocks were examined. Chemical weathering potential of rocks was described by the sulfur as a acceleration factor of weathering and carbonate contents as a neutralization factor of it. The carbonate contents in the rocks were measured accurately by the gas pressure measurement method. Pore water squeezing method was applied for the semi-hard sedimentary rocks (Opalinusclay). The chemical change of extracted pore water under high pressure conditions was estimated. Physical property of sedimentary rocks have relationship among the porosity and permeability and resistivity coefficient in the same rock types. It is possible to estimate the water permeability from the geophysical tests. (author)

The Galaxy Hosts And Large-Scale Environments of Short-Hard Gamma-Ray Bursts

International Nuclear Information System (INIS)

Prochaska, Jason X.; Bloom, J.S.; Chen, H.-W.; Foley, R.J.; Perley, D.A.; Ramirez-Ruiz, E.; Granot, J.; Lee, W.H.; Pooley, D.; Alatalo, K.; Hurley, K.; Cooper, M.C.; Dupree, A.K.; Gerke, B.F.; Hansen, B.M.S.; Kalirai, J.S.; Newman, J.A.; Rich, R.M.; Richer, H.; Stanford, S.A.; Stern, D.

2005-01-01

The rapid succession of discovery of short-duration hard-spectrum GRBs has led to unprecedented insights into the energetics of the explosion and nature of the progenitors. Yet short of the detection of a smoking gun, like a burst of coincident gravitational radiation or a Li-Paczynski mini-supernova, it is unlikely that a definitive claim can be made for the progenitors. As was the case with long-duration soft-spectrum GRBs, however, the expectation is that a systematic study of the hosts and the locations of short GRBs could begin to yield fundamental clues about their nature. We present the first aggregate study of the host galaxies of short-duration hard-spectrum GRBs. In particular, we present the Gemini-North and Keck discovery spectra of the galaxies that hosted three short GRBs and a moderate-resolution (R ∼ 6000) spectrum of a fourth host. We find that these short-hard GRBs originate in a variety of low-redshift (z # circle d ot# yr -1 ) or recent star formation. Two of these galaxies are located within a cluster environment. These observations support an origin from the merger of compact stellar remnants, such as double neutron stars of a neutron star-black hole binary. The fourth event, in contrast, occurred within a dwarf galaxy with a star formation rate exceeding 0.5 M # circle d ot# yr -1 . Therefore, it appears that like supernovae of Type Ia, the progenitors of short-hard bursts are created in all galaxy types, suggesting a corresponding class with a wide distribution of delay times between formation and explosion

Phosphine from rocks: mechanically driven phosphate reduction?

Science.gov (United States)

Glindemann, Dietmar; Edwards, Marc; Morgenstern, Peter

2005-11-01

Natural rock and mineral samples released trace amounts of phosphine during dissolution in mineral acid. An order of magnitude more phosphine (average 1982 ng PH3 kg rock and maximum 6673 ng PH3/kg rock) is released from pulverized rock samples (basalt, gneiss, granite, clay, quartzitic pebbles, or marble). Phosphine was correlated to hardness and mechanical pulverization energy of the rocks. The yield of PH3 ranged from 0 to 0.01% of the total P content of the dissolved rock. Strong circumstantial evidence was gathered for reduction of phosphate in the rock via mechanochemical or "tribochemical" weathering at quartz and calcite/marble inclusions. Artificial reproduction of this mechanism by rubbing quartz rods coated with apatite-phosphate to the point of visible triboluminescence, led to detection of more than 70 000 ng/kg PH3 in the apatite. This reaction pathway may be considered a mechano-chemical analogue of phosphate reduction from lightning or electrical discharges and may contribute to phosphine production via tectonic forces and processing of rocks.

'Between a rock and a hard place': applied anthropology and AIDS research on a commercial farm in Zambia.

Science.gov (United States)

Bond, V

1997-01-01

Fieldwork on a commercial farm in southern Zambia, which was aimed at designing an HIV prevention program for farm workers, gradually exposed the nature of sexual liaisons between young girls, coming to work on the farm from the surrounding villages, and older migrant men workers. Before completing fieldwork, the anthropologist voiced her concern about the implications of these liaisons for the spread of STDs and HIV with the local rural community, farm management and farm workers. The immediate outcome of her intercessions was the decision by management to sack under-age workers. Although some members of the local community, including local research assistants, and some managers and workers welcomed this decision, others were angered by it. Caught between interest groups and conflicting guidelines, the anthropologist, it is argued, was in a no-win situation, 'between a rock and a hard place'. The paper proposes that the application of anthropological ethics in AIDS research needs some re-evaluation.

Standard hardness conversion tables for metals relationship among brinell hardness, vickers hardness, rockwell hardness, superficial hardness, knoop hardness, and scleroscope hardness

CERN Document Server

American Society for Testing and Materials. Philadelphia

2007-01-01

1.1 Conversion Table 1 presents data in the Rockwell C hardness range on the relationship among Brinell hardness, Vickers hardness, Rockwell hardness, Rockwell superficial hardness, Knoop hardness, and Scleroscope hardness of non-austenitic steels including carbon, alloy, and tool steels in the as-forged, annealed, normalized, and quenched and tempered conditions provided that they are homogeneous. 1.2 Conversion Table 2 presents data in the Rockwell B hardness range on the relationship among Brinell hardness, Vickers hardness, Rockwell hardness, Rockwell superficial hardness, Knoop hardness, and Scleroscope hardness of non-austenitic steels including carbon, alloy, and tool steels in the as-forged, annealed, normalized, and quenched and tempered conditions provided that they are homogeneous. 1.3 Conversion Table 3 presents data on the relationship among Brinell hardness, Vickers hardness, Rockwell hardness, Rockwell superficial hardness, and Knoop hardness of nickel and high-nickel alloys (nickel content o...

Insight into subdecimeter fracturing processes during hydraulic fracture experiment in Äspö hard rock laboratory, Sweden

Science.gov (United States)

Kwiatek, Grzegorz; Martínez-Garzón, Patricia; Plenkers, Katrin; Leonhardt, Maria; Zang, Arno; Dresen, Georg; Bohnhoff, Marco

2017-04-01

We analyze the nano- and picoseismicity recorded during a hydraulic fracturing in-situ experiment performed in Äspö Hard Rock Laboratory, Sweden. The fracturing experiment included six fracture stages driven by three different water injection schemes (continuous, progressive and pulse pressurization) and was performed inside a 28 m long, horizontal borehole located at 410 m depth. The fracturing process was monitored with two different seismic networks covering a wide frequency band between 0.01 Hz and 100000 Hz and included broadband seismometers, geophones, high-frequency accelerometers and acoustic emission sensors. The combined seismic network allowed for detection and detailed analysis of seismicity with moment magnitudes MW<-4 (source sizes approx. on cm scale) that occurred solely during the hydraulic fracturing and refracturing stages. We relocated the seismicity catalog using the double-difference technique and calculated the source parameters (seismic moment, source size, stress drop, focal mechanism and seismic moment tensors). The physical characteristics of induced seismicity are compared to the stimulation parameters and to the formation parameters of the site. The seismic activity varies significantly depending on stimulation strategy with conventional, continuous stimulation being the most seismogenic. We find a systematic spatio-temporal migration of microseismic events (propagation away and towards wellbore injection interval) and temporal transitions in source mechanisms (opening - shearing - collapse) both being controlled by changes in fluid injection pressure. The derived focal mechanism parameters are in accordance with the local stress field orientation, and signify the reactivation of pre-existing rock flaws. The seismicity follows statistical and source scaling relations observed at different scales elsewhere, however, at an extremely low level of seismic efficiency.

Biogeochemical Reactive Transport Model of the Redox Zone Experiment of the sp Hard Rock Laboratory in Sweden

International Nuclear Information System (INIS)

Molinero-Huguet, Jorge; Samper-Calvete, F. Javier; Zhang, Guoxiang; Yang, Changbing

2004-01-01

Underground facilities are being operated by several countries around the world for performing research and demonstration of the safety of deep radioactive waste repositories. The ''sp'' Hard Rock Laboratory is one such facility launched and operated by the Swedish Nuclear Fuel and Waste Management Company where various in situ experiments have been performed in fractured granites. One such experiment is the redox zone experiment, which aimed at evaluating the effects of the construction of an access tunnel on the hydrochemical conditions of a fracture zone. Dilution of the initially saline groundwater by fresh recharge water is the dominant process controlling the hydrochemical evolution of most chemical species, except for bicarbonate and sulfate, which unexpectedly increase with time. We present a numerical model of water flow, reactive transport, and microbial processes for the redox zone experiment. This model provides a plausible quantitatively based explanation for the unexpected evolution of bicarbonate and sulfate, reproduces the breakthrough curves of other reactive species, and is consistent with previous hydrogeological and solute transport models

New developments of the Integrated Stress Determination Method and application to the Aespoe Hard Rock Laboratory, Sweden

International Nuclear Information System (INIS)

Ask, Daniel

2004-04-01

This thesis presents new developments of the Integrated Stress Determination Method (ISDM) with application to the Aespoe Hard Rock Laboratory (HRL), Oskarshamn, Sweden. The new developments involve a 12-parameter representation of the regional stress field in the rock mass. The method is applicable to data from hydraulic fracturing, hydraulic tests on pre-existing fractures (HTPF), and overcoring data from CSIR- and CSIRO-type of devices. When hydraulic fracturing/HTPF data are combined with overcoring data, the former may be used to constrain the elastic parameters, i.e. the problem involves 14 model parameters. The Swedish Nuclear Fuel and Waste Management Co. (SKB), have conducted a vast amount of rock stress measurements at the Aespoe HRL since the late 1980s. However, despite the large number of stress measurement data collected in this limited rock volume, variability in the stress field exists. Not only does the result vary depending on measuring technique, e.g. overcoring data indicated larger stress magnitudes compared to hydraulic fracturing data; the results are also affected by existing discontinuities, indicated by non-linear stress magnitudes and orientations versus depth. The objectives for this study are therefore threefold: (1) find explanations to the observed differences between existing hydraulic and overcoring stress data at the Aspo HRL; (2) explain the non-linear stress distribution indicated by existing stress data; and (3) apply the ISDM, including the new developments, based on the results obtained in step 1 and 2. To evaluate the observed differences between existing hydraulic and overcoring stress data, a detailed re-interpretation was conducted. Several measurement-related uncertainties were identified and corrected for when possible, which effectively reduced the discrepancies between the hydraulic and overcoring measuring results. Modeling studies managed by SKB have shown that the redistribution of the stresses at Aespoe HRL to a

Study of the Peak Shear Strength of a Cement-Filled Hard Rock Joint

Science.gov (United States)

She, Cheng-Xue; Sun, Fu-Ting

2018-03-01

The peak shear strength of a cement-filled hard rock joint is studied by theoretical analysis and laboratory testing. Based on the concept of the shear resistance angle, by combining the statistical method and fractal theory, three new parameters are proposed to characterize the three-dimensional joint morphology, reflecting the effects of the average roughness, multi-scale asperities and the dispersion degree of the roughness distribution. These factors are independent of the measurement scale, and they reflect the anisotropy of the joint roughness. Compressive shear tests are conducted on cement-filled joints. Because joints without cement can be considered special cement-filled joints in which the filling degree of cement is zero, they are also tested. The cement-filled granite joint fails primarily along the granite-cement interfaces. The filling degree of cement controls the joint failure and affects its mechanical behaviour. With a decrease in the filling degree of cement, the joint cohesion decreases; however, the dilatancy angle and the basic friction angle of the interface increase. As the filling degree approaches zero, the cohesion approaches zero, while the dilatancy angle and the basic friction angle increase to those of the joint without cement. A set of formulas is proposed to evaluate the peak shear strength of the joints with and without cement. The formulas are shown to be reasonable by comparison with the tested peak shear strength, and they reflect the anisotropy of the strength. This research deepens the understanding of cement-filled joints and provides a method to evaluate their peak shear strength.

Geological disposal of high-level radioactive waste. Conceptual repository design in hard rock

International Nuclear Information System (INIS)

Beale, H.; Griffin, J.R.; Davies, J.W.; Burton, W.R.

1980-01-01

The paper gives an interim report on UK studies on possible designs for a repository for vitrified high-level radioactive waste in crystalline rock. The properties of the waste are described and general technical considerations of consequences of disposal in the rock. As an illustration, two basic designs are described associated with pre-cooling in an intermediate store. Firstly, a 'wet repository' is outlined wherein canisters are sealed up closely in boreholes in the rock in regions of low groundwater movement. Secondly, a 'dry repository' above sea level is described where emplacement in tunnels is followed by a loose backfill containing activity absorbers. A connection to deep permeable strata maintains water levels below emplacement positions. Variants on the two basic schemes (tunnel emplacement in a wet repository and in situ cooling) are also assessed. It is concluded that all designs discussed produce a size of repository feasible for construction in the UK. Further, (1) a working figure of 100 0 C per maximum rock temperature is not exceeded, (2) no insuperable engineering problems have so far been found, though rock mechanics studies are at an early stage; (3) it is not possible to discount the escape of a few long-lived 'man-made' isotopes. A minute increment to natural activity in the biosphere may occur from traces of uranium and its decay chains; (4) at this stage, all the designs are still possible candidates for the construction of a UK repository. (author)

Chemical buffering capacity of clay rock

International Nuclear Information System (INIS)

Beaucaire, C.; Pearson, F.J.; Gautschi, A.

2004-01-01

The long-term performance of a nuclear waste repository is strongly dependent on the chemical properties of the host rock. The host rock establishes the chemical environment that determines such important performance attributes as radionuclide solubilities from the waste and the transport rates from the repository to the accessible environment. Clay-rich rocks are especially favourable host rocks because they provide a strong buffering capacity to resist chemical changes prompted either internally, by reactions of the waste itself and emplacement materials, or externally, by changes in the hydrologic systems surrounding the host rock. This paper will focus on three aspects of the stability of clay-rich host rocks: their ability to provide pCO 2 and redox buffering, and to resist chemical changes imposed by changes in regional hydrology and hydro-chemistry. (authors)

Rock and drugs: multiliteracies and an aesthetics of violence for teenagers in school

Directory of Open Access Journals (Sweden)

Vera Helena Gomes Wielewicki

2014-08-01

Full Text Available Current study discusses an approach of hard rock, in English, for high school students, from a multimodal perspective. The songs are analyzed in terms of their musicality and literariness and hard rock is considered a historically constituted complex cultural movement. The aesthetics of violence, present in the rock’n’roll scenario, specifically focused on the themes of drugs and alcohol abuse, is analyzed from the perspective of multiliteracies, for the development of teenagers’ critical education. The paper is theoretically based on theory by Lévy (2010, Kress (2000 and Kalantzis and Cope (2000 for multiliteracy concepts and on Walser (1993 for the criticism on the musical language. Songs by the USA rock bands Metallica and Guns N’Roses are discussed.

Electron accelerator for tunneling through hard rock

International Nuclear Information System (INIS)

Avery, R.T.; Keefe, D.

1975-10-01

Earlier work demonstrated that intense sub-microsecond bursts of energetic electrons cause significant pulverization and spalling of a variety of rock types. The spall debris generally consists of sand, dust, and small flakes. If carried out at rapid repetition rate, this can lead to a promising technique for increasing the speed and reducing the cost of underground excavation of tunnels, mines, and storage spaces. The conceptual design features of a Pulsed Electron Tunnel Excavator capable of tunneling approximately ten times faster than conventional drill/blast methods are presented, with primary emphasis on the electron accelerator and only a brief description of the tunneling aspects. Of several candidate types of accelerators, a linear induction accelerator producing electron pulses (5 MV, 5 kA, 1.0 μs = 25 kJ) at a 360 Hz rate was selected for the conceptual example. This provides the required average electron beam power output of 9 MW. The feasibility of such an accelerator is discussed

Electron accelerator for tunneling through hard rock

International Nuclear Information System (INIS)

Avery, R.T.; Keefe, D.

1975-01-01

Earlier work demonstrated that intense sub-microsecond bursts of energetic electrons cause significant pulverization and spalling of a variety of rock types. The spall debris generally consists of sand, dust, and small flakes. If carried out at rapid repetition rate, this can lead to a promising technique for increasing the speed and reducing the cost of underground excavation of tunnels, mines, and storage spaces. The conceptual design features of a Pulsed Electron Tunnel Excavator capable of tunneling approximately ten times faster than conventional drill/blast methods are presented with primary emphasis on the electron accelerator and only a brief description of the tunneling aspects. Of several candidate types of accelerators, a linear induction accelerator producing electron pulses (5 MV, 5 kA, 1.0 μs = 25 kJ) at a 360 Hz rate was selected for the conceptual example. This provides the required average electron beam power output of 9 MW. The feasibility of such an accelerator is discussed

Size fraction assaying of gold bearing rocks (for gold extraction) by ...

African Journals Online (AJOL)

A novel method has been developed for processing and extraction of gold from gold bearing rocks for use by small-scale gold miners in Ghana. The methodology involved crushing of gold bearing hard rocks to fine particles to form a composite sample and screening at a range of sizes. Gold distribution in the composite ...

Assessment of groundwater potential based on aquifer properties of hard rock terrain in the Chittar-Uppodai watershed, Tamil Nadu, India

Science.gov (United States)

Kumar, T. Jeyavel Raja; Balasubramanian, A.; Kumar, R. S.; Dushiyanthan, C.; Thiruneelakandan, B.; Suresh, R.; Karthikeyan, K.; Davidraju, D.

2016-06-01

Aquifer performance was tested in 24 locations to assess the groundwater potential of the hard rock terrain in the Chittar-Uppodai watershed of the Tambaraparani River basin. Geologically, the area consists of biotite gneiss, charnockite, and quartzite. The aquifer characteristics, such as transmissivity ( T), the storage coefficient, specific capacity, optimum yield, and the recovery rate were calculated. The drawdown transmissivity was determined using Jacob's straight-line method, while the recovery transmissivity was determined by the Theis method. The drawdown transmissivity was low in the western areas, particularly at Kadayanallur, and was higher in the other areas. The recovery transmissivity was high in the western area, and, with the exception of Gangaikondan, was low at other locations. The assessment indicates that there is groundwater potential in the western part of the study area because of favorable results for recovery drawdown, aquifer thickness, and specific capacity.

Predicting the Performance of Chain Saw Machines Based on Shore Scleroscope Hardness

Science.gov (United States)

Tumac, Deniz

2014-03-01

Shore hardness has been used to estimate several physical and mechanical properties of rocks over the last few decades. However, the number of researches correlating Shore hardness with rock cutting performance is quite limited. Also, rather limited researches have been carried out on predicting the performance of chain saw machines. This study differs from the previous investigations in the way that Shore hardness values (SH1, SH2, and deformation coefficient) are used to determine the field performance of chain saw machines. The measured Shore hardness values are correlated with the physical and mechanical properties of natural stone samples, cutting parameters (normal force, cutting force, and specific energy) obtained from linear cutting tests in unrelieved cutting mode, and areal net cutting rate of chain saw machines. Two empirical models developed previously are improved for the prediction of the areal net cutting rate of chain saw machines. The first model is based on a revised chain saw penetration index, which uses SH1, machine weight, and useful arm cutting depth as predictors. The second model is based on the power consumed for only cutting the stone, arm thickness, and specific energy as a function of the deformation coefficient. While cutting force has a strong relationship with Shore hardness values, the normal force has a weak or moderate correlation. Uniaxial compressive strength, Cerchar abrasivity index, and density can also be predicted by Shore hardness values.

Numerical analysis of control of hard roof's stepped cantilever structure for longwall mining with sublevel caving

Energy Technology Data Exchange (ETDEWEB)

Wei, J.; Jin, Z.; Tang, Y. [Taiyuan University of Technology, Taiyuan (China)

2002-12-01

Based on the field monitoring and simulation test of strata movement, the hard roof's stepped cantilever structure and its mechanics model are presented. The finite element method is used to analyse the effect of hard coal cracking under the abutment pressure of hard roof, so the rational pre-treatment span of hard roof is determined, and the rational working resistance of support is selected also. According to the mechanics model, the transient balance conditions of the hard roof's stepped cantilever structure are studied, and the support-rock relation is theoretically explained. As a result, the basic theory and technique of surrounding rocks control for fully mechanised longwall mining with sub-level caving is formed under the hard roof and hard coal conditions, and the hard roof is effectively controlled not only to protect the working face but also to promote the caving of hard top-coal to increase the recovery rate of coal, thus to realise safe and highly efficient and productive fully mechanised longwall mining with sub-level caving in extra-thick seam. Finally, the successfully practice of hard roof control in 8914 and 8911 working face is presented in this paper. 10 refs., 5 figs., 4 tabs.

Large scale gas injection test (Lasgit) performed at the Aespoe Hard Rock Laboratory. Summary report 2008

International Nuclear Information System (INIS)

Cuss, R.J.; Harrington, J.F.; Noy, D.J.

2010-02-01

This report describes the set-up, operation and observations from the first 1,385 days (3.8 years) of the large scale gas injection test (Lasgit) experiment conducted at the Aespoe Hard Rock Laboratory. During this time the bentonite buffer has been artificially hydrated and has given new insight into the evolution of the buffer. After 2 years (849 days) of artificial hydration a canister filter was identified to perform a series of hydraulic and gas tests, a period that lasted 268 days. The results from the gas test showed that the full-scale bentonite buffer behaved in a similar way to previous laboratory experiments. This confirms the up-scaling of laboratory observations with the addition of considerable information on the stress responses throughout the deposition hole. During the gas testing stage, the buffer was continued to artificially hydrate. Hydraulic results, from controlled and uncontrolled events, show that the buffer continues to mature and has yet to reach full maturation. Lasgit has yielded high quality data relating to the hydration of the bentonite and the evolution in hydrogeological properties adjacent to the deposition hole. The initial hydraulic and gas injection tests confirm the correct working of all control and data acquisition systems. Lasgit has been in successful operation for in excess of 1,385 days

Large scale gas injection test (Lasgit) performed at the Aespoe Hard Rock Laboratory. Summary report 2008

Energy Technology Data Exchange (ETDEWEB)

Cuss, R.J.; Harrington, J.F.; Noy, D.J. (British Geological Survey (United Kingdom))

2010-02-15

This report describes the set-up, operation and observations from the first 1,385 days (3.8 years) of the large scale gas injection test (Lasgit) experiment conducted at the Aespoe Hard Rock Laboratory. During this time the bentonite buffer has been artificially hydrated and has given new insight into the evolution of the buffer. After 2 years (849 days) of artificial hydration a canister filter was identified to perform a series of hydraulic and gas tests, a period that lasted 268 days. The results from the gas test showed that the full-scale bentonite buffer behaved in a similar way to previous laboratory experiments. This confirms the up-scaling of laboratory observations with the addition of considerable information on the stress responses throughout the deposition hole. During the gas testing stage, the buffer was continued to artificially hydrate. Hydraulic results, from controlled and uncontrolled events, show that the buffer continues to mature and has yet to reach full maturation. Lasgit has yielded high quality data relating to the hydration of the bentonite and the evolution in hydrogeological properties adjacent to the deposition hole. The initial hydraulic and gas injection tests confirm the correct working of all control and data acquisition systems. Lasgit has been in successful operation for in excess of 1,385 days

Effects of gas overpressurisation on the geological environment of a deep repository

International Nuclear Information System (INIS)

Nash, P.J.; Rodwell, W.R.

1990-04-01

The effect of gas generated from the deep burial of low and intermediate level radioactive wastes is being assessed. Significant volumes of gas are expected to be produced by anaerobic corrosion of metals and microbial degradation of organic materials. Work is being carried out to determine how easily the gas generated can move away from the repository, since if its flow were impeded the pressure in the repository would rise. If the flow were sufficiently impeded then the pressure rise could ultimately lead to fracturing of the vault or the flow field environment, possibly providing pathways that could accelerate the movement of radionuclides to the surface. This study considers the effects of such an overpressurisation on the integrity of the geological environment containing the repository. It attempts to quantify the pore fluid pressures at which fracturing of hard rock masses may occur by investigating a number of models of rock failure in homogeneously stressed rock and the effects of the presence of an idealised vault on the stress field. A crack opening model has also been developed which considers the effect of the overpressurisation on the dimensions of existing cracks within the rock and hence on the value of its permeability. (Author)

Immobilization of uranium and neptunium by microorganisms in subsurface crystalline rock environments

Energy Technology Data Exchange (ETDEWEB)

Krawczyk-Baersch, Evelyn; Schmeide, Katja; Bok, Frank [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, P.O. Box 51 01 19, D-01314 Dresden (Germany); Pedersen, Karsten [Department of Civil and Environmental Engineering, Chalmers University of Technology, SE-412 96 Goeteborg (Sweden)

2014-07-01

In crystalline rock, the dominant transport medium for radionuclides is groundwater flowing through subsurface fractures. Since groundwater is containing microorganisms, fracture surfaces support biological growth of microbial communities, the so-called bio-films. The microbial diversity of these bio-films depends on the microbial consortia and the chemical composition of the fracture water. Subsurface bio-films have a significant effect on the adsorption capacity of host rock formations by forming a barrier between the rock surface and the groundwater. They can significantly affect subsurface biogeochemical interactions, leading to the immobilization and adsorption of radionuclides. Microbial studies were performed to evaluate the relevance of microbial processes for the immobilization of radionuclides in a deep crystalline repository for high-level radioactive waste. Studies were performed in Olkiluoto, in the rock characterization facility ONKALO in Finland, and in the Aespoe Hard Rock Laboratory (HRL) in Sweden. Massive 5-10-mm thick bio-films were observed in both sites attached to tunnel walls where groundwater was seeping from bedrock fractures. In experiments the effect of uranium on bio-films was studied on site in the ONKALO tunnel by adding UO{sub 2}(ClO{sub 4}){sub 2} with a final U-concentration of 1.0x10{sup -5} M to the fracture water in a self-constructed flow cell by using detached bio-film samples. bio-film specimens collected for transmission electron microscopy studies indicated that uranium in the bio-film was immobilized intracellularly in microorganisms as needle-shaped uranyl phosphate minerals, similar to meta-Autunite (Ca[UO{sub 2}]{sub 2}[PO{sub 4}]{sub 2}.10-12H{sub 2}O). In contrast, thermodynamic calculation of the theoretical predominant fields of uranium species and time-resolved laser fluorescence spectroscopy showed that the formation of aqueous uranium carbonate species Ca{sub 2}UO{sub 2}(CO{sub 3}){sub 3} and Mg{sub 2}UO{sub 2

Response characteristics of reactor building on weathered soft rock ground

International Nuclear Information System (INIS)

Hirata, Kazuta; Tochigi, Hitoshi

1991-01-01

The purpose of this study is to investigate the seismic stability of nuclear power plants on layered soft bedrock grounds, focusing on the seismic response of reactor buildings. In this case, the soft bedrock grounds refer to the weathered soft bedrocks with several tens meter thickness overlaying hard bedrocks. Under this condition, there are two subjects regarding the estimation of the seismic response of reactor buildings. One is the estimation of the seismic response of surface ground, and another is the estimation of soil-structure interaction characteristics for the structures embedded in the layered grounds with low impedandce ratio between the surface ground and the bedrock. Paying attention to these subjects, many cases of seismic response analysis were carried out, and the following facts were clarified. In the soft rock grounds overlaying hard bedrocks, it was proved that the response acceleration was larger than the case of uniform hard bedrocks. A simplified sway and rocking model was proposed to consider soil-structure interaction. It was proved that the response of reactor buildings was small when the effect of embedment was considered. (K.I.)

Depositional environment of the Onverwacht sedimentary rocks Barberton greenstone belt, South Africa

Science.gov (United States)

Paris, I. A.

The Onverwacht Group is the basal part of the ca 3.5 Ga succession forming the Barberton greenstone belt. It comprises a volcanic pile overlain by a thin layer of volcaniclastic sediments which, due to silicification, are extremely well preserved. There has been a controversy as to how and in what environment these sediments were formed, different sets of data being presented to reach opposite conclusions. The Onverwacht Group has been extensively repeated tectonically and here for the first time, sediments from different structural levels are studied together. Three separate facies have been recognised, a distal and proximal turbidite facies and a subaerial facies. Deposition of Onverwacht Group sedimentary rocks occurred in an oceanic basin characterised by the presence of emergent volcanic islands. After eruption, material was deposited both subaerially and in a shallow submarine environment on the volcanic slopes and, as a result of pyroclastic flow, in the deeper parts of the basin.

Rock engineering in Finland

Energy Technology Data Exchange (ETDEWEB)

1986-01-01

Contains a large collection of short articles concerned with tunnels and underground caverns and their construction and use. The articles are grouped under the following headings: use of the subsurface space; water supply; waste water services; energy management (includes articles on power stations, district heating and oil storage and an article on coal storage); multipurpose tunnels; waste disposal; transport; shelters; sporting and recreational amenities located in rock caverns; storage facilities; industrial, laboratory, and service facilities; rock foundations; tourism and culture; utilization of rock masses; research on the disposal of nuclear waste; training and research in the field of rock engineering; site investigation techniques; design of structures in rock; construction; the environment and occupational safety; modern equipment technology; underground space in Helsinki.

The far field heating effects of a radioactive waste depository in hard rock

International Nuclear Information System (INIS)

Hodgkinson, D.P.; Bourke, P.J.

1978-01-01

Fission product heating of the rock surrounding a depository for high level radioactive waste, will result in high temperatures and high thermal gradients over distances of several hundred metres for many centuries. The consequent thermal expansion of the rock leads to stresses which could alter the fracture pattern and therefore the permeability of the rock. These problems are assessed by considering an idealised model of a depository for which analytic solutions to the temperature and stress fields are derived. A related problem is that any water present in the fissures will tend to rise because of its decrease in density on heating. If the water had previously leached away some of the radionuclides in the waste, then this convective transport constitutes a possible leakage path back to the biosphere. For the low permeabilities expected at a depository site, it is possible to linearise the resulting equations and derive analytic solutions for the flow velocities. This procedure has been carried out for the idealised depository model, in order to estimate the magnitude of these effects

Integrating geospatial and ground geophysical information as guidelines for groundwater potential zones in hard rock terrains of south India.

Science.gov (United States)

Rashid, Mehnaz; Lone, Mahjoor Ahmad; Ahmed, Shakeel

2012-08-01

The increasing demand of water has brought tremendous pressure on groundwater resources in the regions were groundwater is prime source of water. The objective of this study was to explore groundwater potential zones in Maheshwaram watershed of Andhra Pradesh, India with semi-arid climatic condition and hard rock granitic terrain. GIS-based modelling was used to integrate remote sensing and geophysical data to delineate groundwater potential zones. In the present study, Indian Remote Sensing RESOURCESAT-1, Linear Imaging Self-Scanner (LISS-4) digital data, ASTER digital elevation model and vertical electrical sounding data along with other data sets were analysed to generate various thematic maps, viz., geomorphology, land use/land cover, geology, lineament density, soil, drainage density, slope, aquifer resistivity and aquifer thickness. Based on this integrated approach, the groundwater availability in the watershed was classified into four categories, viz. very good, good, moderate and poor. The results reveal that the modelling assessment method proposed in this study is an effective tool for deciphering groundwater potential zones for proper planning and management of groundwater resources in diverse hydrogeological terrains.

Rock pushing and sampling under rocks on Mars

Science.gov (United States)

Moore, H.J.; Liebes, S.; Crouch, D.S.; Clark, L.V.

1978-01-01

Viking Lander 2 acquired samples on Mars from beneath two rocks, where living organisms and organic molecules would be protected from ultraviolet radiation. Selection of rocks to be moved was based on scientific and engineering considerations, including rock size, rock shape, burial depth, and location in a sample field. Rock locations and topography were established using the computerized interactive video-stereophotogrammetric system and plotted on vertical profiles and in plan view. Sampler commands were developed and tested on Earth using a full-size lander and surface mock-up. The use of power by the sampler motor correlates with rock movements, which were by plowing, skidding, and rolling. Provenance of the samples was determined by measurements and interpretation of pictures and positions of the sampler arm. Analytical results demonstrate that the samples were, in fact, from beneath the rocks. Results from the Gas Chromatograph-Mass Spectrometer of the Molecular Analysis experiment and the Gas Exchange instrument of the Biology experiment indicate that more adsorbed(?) water occurs in samples under rocks than in samples exposed to the sun. This is consistent with terrestrial arid environments, where more moisture occurs in near-surface soil un- der rocks than in surrounding soil because the net heat flow is toward the soil beneath the rock and the rock cap inhibits evaporation. Inorganic analyses show that samples of soil from under the rocks have significantly less iron than soil exposed to the sun. The scientific significance of analyses of samples under the rocks is only partly evaluated, but some facts are clear. Detectable quantities of martian organic molecules were not found in the sample from under a rock by the Molecular Analysis experiment. The Biology experiments did not find definitive evidence for Earth-like living organisms in their sample. Significant amounts of adsorbed water may be present in the martian regolith. The response of the soil

Aespoe Hard Rock Laboratory. Studies of factors that affect and controls the Excavation Damaged/Disturbed Zone

International Nuclear Information System (INIS)

Jonsson, Martin; Baeckstroem, Ann; Quanhong Feng; Berglund, Johan; Johansson, Malin; Mas Ivars, Diego; Olsson, Mats

2009-05-01

A tunnel was developed at the Aespoe Hard Rock Laboratory (HRL) in 2003 purposely for a large in-situ rock mechanics experiment, the Aespoe Pillar Stability Experiment (APSE). The tunnel had a large height/width ratio with a circular floor, primarily to control the stress situation around the tunnel and concentrate the stresses under the floor. An extensive set of data for understanding the Excavation Damaged Zone (EDZ) was collected within section 47 of the tunnel. It consist of the blast design, blast sequences, convergence measurements during excavation, geological mapping of tunnel and cores, 3D-laser scanning of the tunnel geometry etc. Furthermore, in 2006, ultrasonic measurements along eight boreholes were carried out in order to estimate the extent of the EDZ in the tunnel. The collection of all these different information provides an opportunity to evaluate the mechanical damages caused by the excavation work. The overall aim with this project is to give feed-back to future planning of tunnelling on issues of importance for requirements with respect to minimising the EDZ in crystalline rock from the drill and blast method. A combination of the mapped geological features (tunnel and cores) and the geometry of the blasted tunnel obtained from the 3D-laser scanning were used to build a 3D model of the geology with emphasis on the geometry of the natural fractures. The rock mechanic response to the tunnelling was evaluated in a numerical model including the as-built geometry in combination with the 3D model of the geology. The modelling of the rock mechanical processes of importance for the EDZ could be calibrated against actual measurements. From observed changes in the ultrasonic wave velocity along the boreholes it was found that the locations of the velocity changes corresponded well with the location of the mapped fractures in the drill cores. This indicates that EDZ can be detected using the ultrasonic method with high accuracy. Furthermore, the

Aespoe Hard Rock Laboratory. Studies of factors that affect and controls the Excavation Damaged/Disturbed Zone

Energy Technology Data Exchange (ETDEWEB)

Jonsson, Martin; Baeckstroem, Ann; Quanhong Feng (AaF - Berg och Maetteknik, Stockholm (Sweden)); Berglund, Johan (Vattenfall Power Consultant, Stockholm (Sweden)); Johansson, Malin; Mas Ivars, Diego (Itasca Geomekanik AB, Solna (Sweden)); Olsson, Mats (SweBefo, Stockholm (Sweden))

2009-07-15

A tunnel was developed at the Aespoe Hard Rock Laboratory (HRL) in 2003 purposely for a large in-situ rock mechanics experiment, the Aespoe Pillar Stability Experiment (APSE). The tunnel had a large height/width ratio with a circular floor, primarily to control the stress situation around the tunnel and concentrate the stresses under the floor. An extensive set of data for understanding the Excavation Damaged Zone (EDZ) was collected within section 47 of the tunnel. It consist of the blast design, blast sequences, convergence measurements during excavation, geological mapping of tunnel and cores, 3D-laser scanning of the tunnel geometry etc. Furthermore, in 2006, ultrasonic measurements along eight boreholes were carried out in order to estimate the extent of the EDZ in the tunnel. The collection of all these different information provides an opportunity to evaluate the mechanical damages caused by the excavation work. The overall aim with this project is to give feed-back to future planning of tunnelling on issues of importance for requirements with respect to minimising the EDZ in crystalline rock from the drill and blast method. A combination of the mapped geological features (tunnel and cores) and the geometry of the blasted tunnel obtained from the 3D-laser scanning were used to build a 3D model of the geology with emphasis on the geometry of the natural fractures. The rock mechanic response to the tunnelling was evaluated in a numerical model including the as-built geometry in combination with the 3D model of the geology. The modelling of the rock mechanical processes of importance for the EDZ could be calibrated against actual measurements. From observed changes in the ultrasonic wave velocity along the boreholes it was found that the locations of the velocity changes corresponded well with the location of the mapped fractures in the drill cores. This indicates that EDZ can be detected using the ultrasonic method with high accuracy. Furthermore, the

In situ heating experiments in hard rock: their objectives and design

International Nuclear Information System (INIS)

Cook, N.G.W.; Witherspoon, P.A.; California Univ., Berkeley

1978-01-01

Of the many alternatives that are being considered for the disposal of nuclear wastes, deep underground burial is favored. The wealth of experience concerning the design and construction of underground excavations does not include the unique effects of heating excavations by radioactive decay, nor the issue of long-term isolation. The effects of heating are important in establishing the feasibility of this method of disposal and are essential for the design of an underground repository. Near-field phenomena around individual canisters can be studied by full-scale experiments, using electrical heaters. The thermal diffusivity of rock is so low that information concerning the interaction between full-scale heaters and of the effects of heating a large volume of rock cannot be measured in full-scale experiments lasting less than a few decades. To overcome this difficulty, a time-scaled heating experiment has been developed in which a reduction in linear scale is accompanied by an acceleration of the time scale to the second power. In this experiment, the linear scale is about a third, so that the time scale is about ten fold

In situ heating experiments in hard rock: their objectives and design

International Nuclear Information System (INIS)

Cook, N.G.W.; Witherspoon, P.A.

1978-01-01

Of the many alternatives that are being considered for the disposal of nuclear wastes, deep underground burial is favored. The wealth of experience concerning the design and construction of underground excavations does not include the unique effects of heating excavations by radioactive decay, nor the issue of long-term isolation. The effects of heating are important in establishing the feasibility of this method of disposal, and are essential for the design of an underground repository. Near-field phenomena around individual canisters can be studied by full-scale experiments, using electrical heaters. The thermal diffusivity of rock is so low that information concerning the interaction between full-scale heaters and of the effects of heating a large volume of rock cannot be measured in full-scale experiments lasting less than a few decades. To overcome this difficulty, a time-scaled heating experiment has been developed in which a reduction in linear scale is accompanied by an acceleration of the time scale to the second power. In this experiment, the linear scale is about a third, so that the time scale is about ten fold

Precambrian evolution and the rock record

Science.gov (United States)

Awramik, S.

1985-01-01

The Precambrian time which refers to geological time prior to the first appearance of animals with mineralized hard parts was investigated. Best estimates for this event are around 570 million years ago. Because the rock record begins some 3,800 million years ago the Precambrian encompasses about 84% of geologic time. The fossil record for this immense span of time is dominated by prokaryotes and the sedimentary structures produced by them. The first fossil remains that are considered eukaryotic are found in 1,000 million year old rocks. The first animals may be as old as 700 million years. The fossil records of the first 84% of the Earth's history are collected and described.

Apparatus and method for large tunnel excavation in hard rock

International Nuclear Information System (INIS)

Altseimer, J.H.; Hanold, R.J.

1975-01-01

A tunneling machine is described for producing large tunnels in rock by progressive detachment of the tunnel core by thermal melting a boundary kerf into the tunnel face and simultaneously forming an initial tunnel wall support by deflecting the molten materials against the tunnel walls to provide, when solidified, a continuous liner; and fragmenting the tunnel core circumscribed by the kerf by thermal stress fracturing and in which the heat required for such operations is supplied by a compact nuclear reactor. (U.S.)

Simulating the time-dependent behaviour of excavations in hard rock

CSIR Research Space (South Africa)

Malan, DF

2002-10-01

Full Text Available (1993) estimated the rock disintegration of the roof of the Swedish repository at Forsmark where the excavation is intersected by a fracture zone. By generalising the structure to be one of regular layers of blocks and applying a log- time creep law, he... and secondary closure in squeezing tunnels. Tertiary movements can be considered by providing suitable laws relating the values of the mechanical parameters (such as viscosity) to the irreversible part of the time-dependent strain. These rheological models...

Rock shape, restitution coefficients and rockfall trajectory modelling

Science.gov (United States)

Glover, James; Christen, Marc; Bühler, Yves; Bartelt, Perry

2014-05-01

Restitution coefficients are used in rockfall trajectory modelling to describe the ratio between incident and rebound velocities during ground impact. They are central to the problem of rockfall hazard analysis as they link rock mass characteristics to terrain properties. Using laboratory experiments as a guide, we first show that restitution coefficients exhibit a wide range of scatter, although the material properties of the rock and ground are constant. This leads us to the conclusion that restitution coefficients are poor descriptors of rock-ground interaction. The primary problem is that "apparent" restitution coefficients are applied at the rock's centre-of-mass and do not account for rock shape. An accurate description of the rock-ground interaction requires the contact forces to be applied at the rock surface with consideration of the momentary rock position and spin. This leads to a variety of rock motions including bouncing, sliding, skipping and rolling. Depending on the impact configuration a wide range of motions is possible. This explains the large scatter of apparent restitution coefficients. We present a rockfall model based on newly developed hard-contact algorithms which includes the effects of rock shape and therefore is able to reproduce the results of different impact configurations. We simulate the laboratory experiments to show that it is possible to reproduce run-out and dispersion of different rock shapes using parameters obtained from independent tests. Although this is a step forward in rockfall trajectory modelling, the problem of parametersing real terrain remains.

Superhard nanophase cutter materials for rock drilling applications; FINAL

International Nuclear Information System (INIS)

Voronov, O.; Tompa, G.; Sadangi, R.; Kear, B.; Wilson, C.; Yan, P.

2000-01-01

The Low Pressure-High Temperature (LPHT) System has been developed for sintering of nanophase cutter and anvil materials. Microstructured and nanostructured cutters were sintered and studied for rock drilling applications. The WC/Co anvils were sintered and used for development of High Pressure-High Temperature (HPHT) Systems. Binderless diamond and superhard nanophase cutter materials were manufactured with help of HPHT Systems. The diamond materials were studied for rock machining and drilling applications. Binderless Polycrystalline Diamonds (BPCD) have high thermal stability and can be used in geothermal drilling of hard rock formations. Nanophase Polycrystalline Diamonds (NPCD) are under study in precision machining of optical lenses. Triphasic Diamond/Carbide/Metal Composites (TDCC) will be commercialized in drilling and machining applications

Aespoe Hard Rock Laboratory Annual Report 2004

International Nuclear Information System (INIS)

2005-08-01

At Aespoe HRL, methods for characterising a suitable site for a deep repository are being developed and tested. The underground part of the laboratory consists of a tunnel from the Simpevarp peninsula to the southern part of Aespoe where the tunnel continues in a spiral down to a depth of 460 m. Aespoe HRL has been in operation since 1995. Most of the research is focused on processes of importance for the long-term safety of a future deep repository. To meet the overall time schedule for SKB's RDandD work, the following stage goals were initially defined for the work at the Aespoe HRL. 1. Verify pre-investigation methods. Demonstrate that investigations on the ground surface and in boreholes provide sufficient data on essential safety-related properties of the rock at repository level. 2. Finalise detailed investigation methodology. Refine and verify the methods and the technology needed for characterisation of the rock in the detailed site investigations. 3. Test models for description of the barrier functions at natural conditions. Further develop and at repository depth test methods and models for description of groundwater flow, radionuclide migration, and chemical conditions during operation of a repository and after closure. 4. Demonstrate technology for and function of important parts of the repository system. Test, investigate and demonstrate on full-scale different components of importance for the long-term safety of a deep repository and to show that high quality can be achieved in design, construction, and operation of repository components. Stage goals 1 and 2 have been concluded at Aespoe HRL and the tasks have been transferred to the Site Investigation Department of SKB which performs site investigations at two sites, Simpevarp/Laxemar in the municipality of Oskarshamn and Forsmark in the municipality of Oesthammar. In order to reach present goals the following important tasks are performed at the Aespoe HRL: Develop, test, evaluate and demonstrate

Aespoe Hard Rock Laboratory Annual Report 2004

Energy Technology Data Exchange (ETDEWEB)

NONE

2005-08-01

At Aespoe HRL, methods for characterising a suitable site for a deep repository are being developed and tested. The underground part of the laboratory consists of a tunnel from the Simpevarp peninsula to the southern part of Aespoe where the tunnel continues in a spiral down to a depth of 460 m. Aespoe HRL has been in operation since 1995. Most of the research is focused on processes of importance for the long-term safety of a future deep repository. To meet the overall time schedule for SKB's RDandD work, the following stage goals were initially defined for the work at the Aespoe HRL. 1. Verify pre-investigation methods. Demonstrate that investigations on the ground surface and in boreholes provide sufficient data on essential safety-related properties of the rock at repository level. 2. Finalise detailed investigation methodology. Refine and verify the methods and the technology needed for characterisation of the rock in the detailed site investigations. 3. Test models for description of the barrier functions at natural conditions. Further develop and at repository depth test methods and models for description of groundwater flow, radionuclide migration, and chemical conditions during operation of a repository and after closure. 4. Demonstrate technology for and function of important parts of the repository system. Test, investigate and demonstrate on full-scale different components of importance for the long-term safety of a deep repository and to show that high quality can be achieved in design, construction, and operation of repository components. Stage goals 1 and 2 have been concluded at Aespoe HRL and the tasks have been transferred to the Site Investigation Department of SKB which performs site investigations at two sites, Simpevarp/Laxemar in the municipality of Oskarshamn and Forsmark in the municipality of Oesthammar. In order to reach present goals the following important tasks are performed at the Aespoe HRL: Develop, test, evaluate and

Hydrological and geochemical investigation on the volcanic rock and gneissic rock area

Energy Technology Data Exchange (ETDEWEB)

Koh, Yong Kwon; Jeong, Chan Ho; Ryu, Kun Seok; Kim, Byoung Yeop; Park, Hyung Kun; Yu, Sang Woo; Jang, Hyu Kun; Lee, Suk Chi; Choi, Ki Young; Jeon, Hyu Woong; Kim, Do Hyoung [Daejong University, Daejeon (Korea, Republic of)

2010-01-15

The purpose of this study is to supply the basic data and optimum study site among volcanic rock area and gneissic rock area for high-level radioactive waste disposal. For this purpose, geological, hydrogeological and geochemical data from previously published literatures were collected and analyzed. In this study, we selected 36 volcanic rock sites and 26 gneissic sites as the candidate sites for high level radwaste disposal. Finally, for four sites(M-1, M-13, V-1 and V-13 sites) were selected as the study sites. The geochemical characteristics of groundwaters of each study site were statistically analyzed. The nitrate contamination and the sea water mixing will be important factors on the assessment of behaviour of radionuclides under groundwater environment. From the deep geothermal study, alkaline and sodium-bicarbonate chemical environment, and sea water mixing should be considered as the key factors for the deep disposal of high-level radioactive waste

Uranium mineralization by ground water in sedimentary rocks, Japan

International Nuclear Information System (INIS)

Doi, K.; Hirono, S.; Sakamaki, Y.

1975-01-01

To solve the mechanism of uranium concentration in stratabound uranium deposits occurring in the basal part of Neogene sediments overlying granite basement, attention was paid to uranium leaching from weathered granite by circulating carbonated fissure waters, to effective adsorbents for fixing uranium from uraniferous ground waters, to structural features controlling the ground-water circulation, and other relevant factors. The evidence for uranium transportation by hydothermal solutions, including hot spring waters, is hard to observe. Conclusions are summarized as follows: Uranium in the deposits is supplied from surrounding source rocks, mostly from granite. Uranium is transported by circulating ground-water solutions. The uranium dissolved in ground water is fixed in minerals in various ways, the most important being adsorption by carbonaceous matter. Ore-grade uranium concentrated from very dilute solutions occurs by multiple repetition of a leaching-and-fixation cycle between minerals or adsorbents and circulating uraniferous ground water. Important factors for uranium mineralization are sufficient uranium, supplied mostly from granite, the existence of effective adsorbents such as carbonaceous matter in the host rocks, and favorable geological, geochemical, and geophysical environments. The last seem to require not only physical and chemical conditions but also correct flow and volume of ground water. (U.S.)

Whole-body Vibration Exposure of Drill Operators in Iron Ore Mines and Role of Machine-Related, Individual, and Rock-Related Factors

Directory of Open Access Journals (Sweden)

Dhanjee Kumar Chaudhary

2015-12-01

Conclusion: Prevention should include using appropriate machines to handle rock hardness, rock uniaxial compressive strength and density, and seat improvement using ergonomic approaches such as including a suspension system.

Alteration of Lunar Rock Surfaces through Interaction with the Space Environment

Science.gov (United States)

Frushour, A. M.; Noble, S. K; Christoffersen, R.; Keller, L P.

2014-01-01

Space weathering occurs on all ex-posed surfaces of lunar rocks, as well as on the surfaces of smaller grains in the lunar regolith. Space weather-ing alters these exposed surfaces primarily through the action of solar wind ions and micrometeorite impact processes. On lunar rocks specifically, the alteration products produced by space weathering form surface coatings known as patina. Patinas can have spectral reflectance properties different than the underlying rock. An understanding of patina composition and thickness is therefore important for interpreting re-motely sensed data from airless solar system bodies. The purpose of this study is to try to understand the physical and chemical properties of patina by expanding the number of patinas known and characterized in the lunar rock sample collection.

P-wave velocity changes in freezing hard low-porosity rocks: a laboratory-based time-average model

Directory of Open Access Journals (Sweden)

D. Draebing

2012-10-01

Full Text Available P-wave refraction seismics is a key method in permafrost research but its applicability to low-porosity rocks, which constitute alpine rock walls, has been denied in prior studies. These studies explain p-wave velocity changes in freezing rocks exclusively due to changing velocities of pore infill, i.e. water, air and ice. In existing models, no significant velocity increase is expected for low-porosity bedrock. We postulate, that mixing laws apply for high-porosity rocks, but freezing in confined space in low-porosity bedrock also alters physical rock matrix properties. In the laboratory, we measured p-wave velocities of 22 decimetre-large low-porosity (< 10% metamorphic, magmatic and sedimentary rock samples from permafrost sites with a natural texture (> 100 micro-fissures from 25 °C to −15 °C in 0.3 °C increments close to the freezing point. When freezing, p-wave velocity increases by 11–166% perpendicular to cleavage/bedding and equivalent to a matrix velocity increase from 11–200% coincident to an anisotropy decrease in most samples. The expansion of rigid bedrock upon freezing is restricted and ice pressure will increase matrix velocity and decrease anisotropy while changing velocities of the pore infill are insignificant. Here, we present a modified Timur's two-phase-equation implementing changes in matrix velocity dependent on lithology and demonstrate the general applicability of refraction seismics to differentiate frozen and unfrozen low-porosity bedrock.

Modeling of Micro Deval abrasion loss based on some rock properties

Science.gov (United States)

Capik, Mehmet; Yilmaz, Ali Osman

2017-10-01

Aggregate is one of the most widely used construction material. The quality of the aggregate is determined using some testing methods. Among these methods, the Micro Deval Abrasion Loss (MDAL) test is commonly used for the determination of the quality and the abrasion resistance of aggregate. The main objective of this study is to develop models for the prediction of MDAL from rock properties, including uniaxial compressive strength, Brazilian tensile strength, point load index, Schmidt rebound hardness, apparent porosity, void ratio Cerchar abrasivity index and Bohme abrasion test are examined. Additionally, the MDAL is modeled using simple regression analysis and multiple linear regression analysis based on the rock properties. The study shows that the MDAL decreases with the increase of uniaxial compressive strength, Brazilian tensile strength, point load index, Schmidt rebound hardness and Cerchar abrasivity index. It is also concluded that the MDAL increases with the increase of apparent porosity, void ratio and Bohme abrasion test. The modeling results show that the models based on Bohme abrasion test and L type Schmidt rebound hardness give the better forecasting performances for the MDAL. More models, including the uniaxial compressive strength, the apparent porosity and Cerchar abrasivity index, are developed for the rapid estimation of the MDAL of the rocks. The developed models were verified by statistical tests. Additionally, it can be stated that the proposed models can be used as a forecasting for aggregate quality.

Rock breaking methods to replace blasting

Science.gov (United States)

Zhou, Huisheng; Xie, Xinghua; Feng, Yuqing

2018-03-01

The method of breaking rock by blasting has a high efficiency and the cost is relatively low, but the associated vibration, flyrock, production of toxic gases since the 1970’s, the Western developed countries began to study the safety of breaking rock. This paper introduces different methods and their progress to safely break rock. Ideally, safe rock breaking would have little vibration, no fly stone, and no toxic gases, which can be widely used in municipal engineering, road excavation, high-risk mining, quarrying and complex environment.

Rock properties data base

Energy Technology Data Exchange (ETDEWEB)

Jackson, R.; Gorski, B.; Gyenge, M.

1991-03-01

As mining companies proceed deeper and into areas whose stability is threatened by high and complex stress fields, the science of rock mechanics becomes invaluable in designing underground mine strata control programs. CANMET's Mining Research Laboratories division has compiled a summary of pre- and post-failure mechanical properties of rock types which were tested to provide design data. The 'Rock Properties Data Base' presents the results of these tests, and includes many rock types typical of Canadian mine environments. The data base also contains 'm' and 's' values determined using Hoek and Brown's failure criteria for both pre- and post-failure conditions. 7 refs., 3 tabs., 9 figs., 1 append.

Time-lapse electrical surveys to locate infiltration zones in weathered hard rock tropical areas

Science.gov (United States)

Wubda, M.; Descloitres, M.; Yalo, N.; Ribolzi, O.; Vouillamoz, J. M.; Boukari, M.; Hector, B.; Séguis, L.

2017-07-01

In West Africa, infiltration and groundwater recharge processes in hard rock areas are depending on climatic, surface and subsurface conditions, and are poorly documented. Part of the reason is that identification, location and monitoring of these processes is still a challenge. Here, we explore the potential for time-lapse electrical surveys to bring additional information on these processes for two different climate situations: a semi-arid Sahelian site (north of Burkina and a humid Sudanian site (north of Benin), respectively focusing on indirect (localized) and direct (diffuse) recharge processes. The methodology is based on surveys in dry season and rainy season on typical pond or gully using Electrical Resistivity Tomography (ERT) and frequency electromagnetic (FEM) apparent conductivity mapping. The results show that in the Sahelian zone an indirect recharge occurs as expected, but infiltration doesn't takes place at the center of the pond to the aquifer, but occurs laterally in the banks. In Sudanian zone, the ERT survey shows a direct recharge process as expected, but also a complicated behavior of groundwater dilution, as well as the role of hardpans for fast infiltration. These processes are ascertained by groundwater monitoring in adjacent observing wells. At last, FEM time lapse mapping is found to be difficult to quantitatively interpreted due to the non-uniqueness of the model, clearly evidenced comparing FEM result to auger holes monitoring. Finally, we found that time-lapse ERT can be an efficient way to track infiltration processes across ponds and gullies in both climatic conditions, the Sahelian setting providing results easier to interpret, due to significant resistivity contrasts between dry and rain seasons. Both methods can be used for efficient implementation of punctual sensors for complementary studies. However, FEM time-lapse mapping remains difficult to practice without external information that renders this method less attractive for

Rock fracture processes in chemically reactive environments

Science.gov (United States)

Eichhubl, P.

2015-12-01

Rock fracture is traditionally viewed as a brittle process involving damage nucleation and growth in a zone ahead of a larger fracture, resulting in fracture propagation once a threshold loading stress is exceeded. It is now increasingly recognized that coupled chemical-mechanical processes influence fracture growth in wide range of subsurface conditions that include igneous, metamorphic, and geothermal systems, and diagenetically reactive sedimentary systems with possible applications to hydrocarbon extraction and CO2 sequestration. Fracture processes aided or driven by chemical change can affect the onset of fracture, fracture shape and branching characteristics, and fracture network geometry, thus influencing mechanical strength and flow properties of rock systems. We are investigating two fundamental modes of chemical-mechanical interactions associated with fracture growth: 1. Fracture propagation may be aided by chemical dissolution or hydration reactions at the fracture tip allowing fracture propagation under subcritical stress loading conditions. We are evaluating effects of environmental conditions on critical (fracture toughness KIc) and subcritical (subcritical index) fracture properties using double torsion fracture mechanics tests on shale and sandstone. Depending on rock composition, the presence of reactive aqueous fluids can increase or decrease KIc and/or subcritical index. 2. Fracture may be concurrent with distributed dissolution-precipitation reactions in the hostrock beyond the immediate vicinity of the fracture tip. Reconstructing the fracture opening history recorded in crack-seal fracture cement of deeply buried sandstone we find that fracture length growth and fracture opening can be decoupled, with a phase of initial length growth followed by a phase of dominant fracture opening. This suggests that mechanical crack-tip failure processes, possibly aided by chemical crack-tip weakening, and distributed solution-precipitation creep in the

Quantification of the specific yield in a two-layer hard-rock aquifer model

Science.gov (United States)

Durand, Véronique; Léonardi, Véronique; de Marsily, Ghislain; Lachassagne, Patrick

2017-08-01

Hard rock aquifers (HRA) have long been considered to be two-layer systems, with a mostly capacitive layer just below the surface, the saprolite layer, and a mainly transmissive layer underneath, the fractured layer. Although this hydrogeological conceptual model is widely accepted today within the scientific community, it is difficult to quantify the respective storage properties of each layer with an equivalent porous medium model. Based on an HRA field site, this paper attempts to quantify in a distinct manner the respective values of the specific yield (Sy) in the saprolite and the fractured layer, with the help of a deterministic hydrogeological model. The study site is the Plancoët migmatitic aquifer located in north-western Brittany, France, with piezometric data from 36 observation wells surveyed every two weeks for eight years. Whereas most of the piezometers (26) are located where the water table lies within the saprolite, thus representing the specific yield of the unconfined layer (Sy1), 10 of them are representative of the unconfined fractured layer (Sy2), due to their position where the saprolite is eroded or unsaturated. The two-layer model, based on field observations of the layer geometry, runs with the MODFLOW code. 81 values of the Sy1/Sy2 parameter sets were tested manually, as an inverse calibration was not able to calibrate these parameters. In order to calibrate the storage properties, a new quality-of-fit criterion called ;AdVar; was also developed, equal to the mean squared deviation of the seasonal piezometric amplitude variation. Contrary to the variance, AdVar is able to select the best values for the specific yield in each layer. It is demonstrated that the saprolite layer is about 2.5 times more capacitive than the fractured layer, with Sy1 = 10% (7% < Sy1 < 15%) against Sy2 = 2% (1% < Sy2 < 3%), in this particular example.

Hard rock excavation at the CSM/OCRD test site using Swedish blast design techniques

International Nuclear Information System (INIS)

Holmberg, R.

1983-09-01

This report is the third in a series describing research conducted by the Colorado School of Mines for the Office of Crystalline Repository Development (OCRD) to determine the extent of blast damage in rock surrounding an underground opening. A special room, called the CSM/OCRD room, was excavated at the CSM experimental mine for the purpose of assessing blast damage in the rock around the room. Even though this mine is not proposed as a nuclear waste repository site, the instrumentation and methods of blast damage assessment developed in this project are applicable to proposed repository sites. This report describes the application of Swedish blasting technology for the excavation of the test room. The design of the blasting patterns including the selection of explosives, hole sizes and location, explosive loading densities, and delay intervals is based upon the theories of Langefors and Kihlstrom in combination with methods used at the Swedish Detonic Research Foundation for minimizing unwanted rock damage. The practical application of the design procedures to seven rounds and the achieved results is discussed

Experimental investigation on hard turning using mixed ceramic insert under accelerated cooling environment

Directory of Open Access Journals (Sweden)

Ramanuj Kumar

2018-05-01

Full Text Available The present study reports on the application of accelerated cooling environment (ACE in hard turning of AISI D2 steel (55 ± 1HRC using mixed ceramic insert (Al2O3 + TiCN which is rarely being investigated and to address the major problems of brittle fracture of tool tip that arises through cutting forces and friction at tool-work and chip-tool interface. In spraying process, some portion of spraying coolant vaporize due to heat when it reaches to cutting zone where as remaining portion of coolant easily penetrate in cutting zone through capillary action and reduces friction as well as heat in cutting zone. Abrasion and chipping are noticed to be dominant wear mechanism. Cutting speed and depth of cut are significant for flank wear as well as cutting temperature whereas feed is significant for average surface roughness. Serrated chips have been identified at higher cutting speed and higher feeds. Optimal parametric combination is found to be d1-f1-v2 (0.1mm-0.04 m/min-108 m/min and tool life and machining cost per part are 70 minutes and Rs 76.76 respectively. Investigation shows the worthy of application of ACE in hard turning in industrial sectors ecologically and economically. Empirical models reveal statistically significance due to higher coefficient of correlations.

Clay club catalogue of characteristics of argillaceous rocks

International Nuclear Information System (INIS)

2005-01-01

The OECD/NEA Working Group on the Characterisation, the Understanding and the Performance of Argillaceous Rocks as Repository Host Formations, namely the Clay Club, examines the various argillaceous rocks that are being considered for the deep geological disposal of radioactive waste, i.e. from plastic, soft, poorly indurated clays to brittle, hard mud-stones or shales. The Clay Club considered it necessary and timely to provide a catalogue to gather in a structured way the key geo-scientific characteristics of the various argillaceous formations that are - or were - studied in NEA member countries with regard to radioactive waste disposal. The present catalogue represents the outcomes of this Clay Club initiative. (author)

Solid as a rock

International Nuclear Information System (INIS)

Pincus, H.J.

1984-01-01

Recent technologic developments have required a more comprehensive approach to the behavior of rock mass or rock substance plus discontinuities than was adequate previously. This work considers the inherent problems in such operations as the storage of hot or cold fluids in caverns and aquifers, underground storage of nuclear waste, underground recovery of heat from hydrocarbon fuels, tertiary recovery of oil by thermal methods, rapid excavation of large openings at shallow to great depths and in hostile environments, and retrofitting of large structures built on or in rock. The standardization of methods for determining rock properties is essential to all of the activities described, for use not only in design and construction but also in site selection and post-construction monitoring. Development of such standards is seen as a multidisciplinary effort

Sedimentary environments and hydrocarbon potential of cretaceous rocks of indus basin, Pakistan

International Nuclear Information System (INIS)

Sheikh, S.A.; Naseem, S.

1999-01-01

Cretaceous rocks of Indus Basin of Pakistan are dominated by clastics with subordinate limestone towards the top. These rocks represent shelf facies and were deposited in deltaic to reducing marine conditions at variable depths. Indications of a silled basin with restricted circulation are also present. Cretaceous fine clastics/carbonates have good source and reservoir qualities. Variable geothermal gradients in different parts of basin have placed these rocks at different maturity levels; i.e. from oil to condensate and to gas. The potential of these rocks has been proved by several oil and gas discoveries particularly in the Central and Southern provinces of Indus Basin. (author)

Convergent evidence for widespread rock nitrogen sources in Earth’s surface environment

Science.gov (United States)

Houlton, B. Z.; Morford, S. L.; Dahlgren, R. A.

2018-04-01

Nitrogen availability is a pivotal control on terrestrial carbon sequestration and global climate change. Historical and contemporary views assume that nitrogen enters Earth’s land-surface ecosystems from the atmosphere. Here we demonstrate that bedrock is a nitrogen source that rivals atmospheric nitrogen inputs across major sectors of the global terrestrial environment. Evidence drawn from the planet’s nitrogen balance, geochemical proxies, and our spatial weathering model reveal that ~19 to 31 teragrams of nitrogen are mobilized from near-surface rocks annually. About 11 to 18 teragrams of this nitrogen are chemically weathered in situ, thereby increasing the unmanaged (preindustrial) terrestrial nitrogen balance from 8 to 26%. These findings provide a global perspective to reconcile Earth’s nitrogen budget, with implications for nutrient-driven controls over the terrestrial carbon sink.

Hard-Rock Stability Analysis for Span Design in Entry-Type Excavations with Learning Classifiers

Directory of Open Access Journals (Sweden)

Esperanza García-Gonzalo

2016-06-01

Full Text Available The mining industry relies heavily on empirical analysis for design and prediction. An empirical design method, called the critical span graph, was developed specifically for rock stability analysis in entry-type excavations, based on an extensive case-history database of cut and fill mining in Canada. This empirical span design chart plots the critical span against rock mass rating for the observed case histories and has been accepted by many mining operations for the initial span design of cut and fill stopes. Different types of analysis have been used to classify the observed cases into stable, potentially unstable and unstable groups. The main purpose of this paper is to present a new method for defining rock stability areas of the critical span graph, which applies machine learning classifiers (support vector machine and extreme learning machine. The results show a reasonable correlation with previous guidelines. These machine learning methods are good tools for developing empirical methods, since they make no assumptions about the regression function. With this software, it is easy to add new field observations to a previous database, improving prediction output with the addition of data that consider the local conditions for each mine.

Hard-Rock Stability Analysis for Span Design in Entry-Type Excavations with Learning Classifiers.

Science.gov (United States)

García-Gonzalo, Esperanza; Fernández-Muñiz, Zulima; García Nieto, Paulino José; Bernardo Sánchez, Antonio; Menéndez Fernández, Marta

2016-06-29

The mining industry relies heavily on empirical analysis for design and prediction. An empirical design method, called the critical span graph, was developed specifically for rock stability analysis in entry-type excavations, based on an extensive case-history database of cut and fill mining in Canada. This empirical span design chart plots the critical span against rock mass rating for the observed case histories and has been accepted by many mining operations for the initial span design of cut and fill stopes. Different types of analysis have been used to classify the observed cases into stable, potentially unstable and unstable groups. The main purpose of this paper is to present a new method for defining rock stability areas of the critical span graph, which applies machine learning classifiers (support vector machine and extreme learning machine). The results show a reasonable correlation with previous guidelines. These machine learning methods are good tools for developing empirical methods, since they make no assumptions about the regression function. With this software, it is easy to add new field observations to a previous database, improving prediction output with the addition of data that consider the local conditions for each mine.

Distribution coefficient of radionuclides on rocks for performance assessment of high-level radioactive waste repository

International Nuclear Information System (INIS)

Shibutani, Tomoki; Shibata, Masahiro; Suyama, Tadahiro

1999-11-01

Distribution coefficients of radionuclides on rocks are selected for safety assessment in the 'Second Progress Report on Research and Development for the geological disposal of HLW in Japan (H12 Report)'. The categorized types of rock are granitic rocks (crystalline and acidic rocks), basaltic rocks (crystalline and basic rocks), psammitic rocks (neogene sedimentary (soft)), and tuffaceous-pelitic rocks (pre-neogene sedimentary rocks (hard)). The types of groundwater are FRHP (fresh reducing high-pH), FRLP (fresh reducing low-pH), SRHP (saline reducing high-pH), SRLP (saline reducing low-pH), MRNP (mixing reducing neutral-pH) and FOHP (fresh oxidizing high-pH) groundwater. The elements to be surveyed are Ni, Se, Zr, Nb, Tc, Pd, Sn, Cs, Sm, Pb, Ra, Ac, Th, Pa, U, Np, Pu, Am and Cm. Distribution coefficients are collected from literatures describing batch sorption experimental results, and are selected under consideration of conservativity. (author)

Aespoe Hard Rock Laboratory. Prototype Repository. Analyses of microorganisms, gases and water chemistry in buffer and backfill, 2009

Energy Technology Data Exchange (ETDEWEB)

Lydmark, Sara (Microbial Analytics Sweden AB (Sweden))

2010-09-15

The Prototype repository is an international project to build and study a full-scale model of the planned Swedish final repository for spent nuclear fuel. The Prototype repository differs from a real storage in that it is drained. For example, this makes the swelling pressure lower in the Prototype repository compared with a real storage. The project is being conducted at the Aespoe Hard Rock Laboratory (HRL) in crystalline rock at a depth of approximately 450 m. A monitoring programme is investigating the evolution of the water chemistry, gas, and microbial activity at the site, and one of the specific aims is to monitor the microbial consumption of oxygen in situ in the Prototype repository. This document describes the results of the analyses of microbes, gases, and chemistry inside and outside the Prototype in 2009. Hydrogen, helium, nitrogen, oxygen, carbon monoxide, carbon dioxide, methane, ethane, and ethene were analysed in the following sampling points in the Prototype repository: KBU10001, KBU10002, KBU10004, KBU10006, KBU10008, KFA01 and KFA04. Where the sampling points in the Prototype delivered pore water, the water was analysed for amount of ATP (i.e., the biovolume), cultivable heterotrophic aerobic bacteria (CHAB), sulphate-reducing bacteria (SRB), methane-oxidizing bacteria (MOB), autotrophic acetogens (AA) and in some cases iron-reducing bacteria (IRB). Cultivation methods were also compared with qPCR molecular techniques to evaluate these before next year's decommission of the Prototype repository. The collected pore water from the Prototype repository was subject to chemistry analysis (as many analyses were conducted as the amount of water allowed). In addition, groundwater from two borehole sections in the rock surrounding the Prototype was analysed regarding its gas composition, microbiology and redox. Chemistry data from a previous investigation of the groundwater outside the Prototype repository were compared with the pore water

Aespoe Hard Rock Laboratory. Prototype Repository. Analyses of microorganisms, gases and water chemistry in buffer and backfill, 2009

International Nuclear Information System (INIS)

Lydmark, Sara

2010-09-01

The Prototype repository is an international project to build and study a full-scale model of the planned Swedish final repository for spent nuclear fuel. The Prototype repository differs from a real storage in that it is drained. For example, this makes the swelling pressure lower in the Prototype repository compared with a real storage. The project is being conducted at the Aespoe Hard Rock Laboratory (HRL) in crystalline rock at a depth of approximately 450 m. A monitoring programme is investigating the evolution of the water chemistry, gas, and microbial activity at the site, and one of the specific aims is to monitor the microbial consumption of oxygen in situ in the Prototype repository. This document describes the results of the analyses of microbes, gases, and chemistry inside and outside the Prototype in 2009. Hydrogen, helium, nitrogen, oxygen, carbon monoxide, carbon dioxide, methane, ethane, and ethene were analysed in the following sampling points in the Prototype repository: KBU10001, KBU10002, KBU10004, KBU10006, KBU10008, KFA01 and KFA04. Where the sampling points in the Prototype delivered pore water, the water was analysed for amount of ATP (i.e., the biovolume), cultivable heterotrophic aerobic bacteria (CHAB), sulphate-reducing bacteria (SRB), methane-oxidizing bacteria (MOB), autotrophic acetogens (AA) and in some cases iron-reducing bacteria (IRB). Cultivation methods were also compared with qPCR molecular techniques to evaluate these before next year's decommission of the Prototype repository. The collected pore water from the Prototype repository was subject to chemistry analysis (as many analyses were conducted as the amount of water allowed). In addition, groundwater from two borehole sections in the rock surrounding the Prototype was analysed regarding its gas composition, microbiology and redox. Chemistry data from a previous investigation of the groundwater outside the Prototype repository were compared with the pore water chemistry

A New Method for Determination of Joint Roughness Coefficient of Rock Joints

Directory of Open Access Journals (Sweden)

Shigui Du

2015-01-01

Full Text Available The joint roughness coefficient (JRC of rock joints has the characteristic of scale effect. JRC measured on small-size exposed rock joints should be evaluated by JRC scale effect in order to obtain the JRC of actual-scale rock joints, since field rock joints are hardly fully exposed or well saved. Based on the validity analysis of JRC scale effect, concepts of rate of JRC scale effect and effective length of JRC scale effect were proposed. Then, a graphic method for determination of the effective length of JRC scale effect was established. Study results show that the JRC of actual-scale rock joints can be obtained through a fractal model of JRC scale effect according to the statistically measured results of the JRC of small-size partial exposed rock joints and by the selection of fractal dimension of JRC scale effect and the determination of effective length of JRC scale effect.

Relationship between the rock mass deformation and places of occurrence of seismological events

Energy Technology Data Exchange (ETDEWEB)

Janusz Makowka; Jozef Kabiesz; Lin-ming Ddou [Central Mining Institute, Katowice (Poland)

2009-09-15

Static effort of rock mass very rarely causes of rock burst in Polish coal mines. Rock bursts with source in the seismic tremor within the roof rock layers are prevailing. A seismic tremor is an effect of rupture or sliding in roof layers above the exploited panel in coal seam, sometime in a distance from actual exploitation. Sliding, as a rule occurs in fault zone and tremors in it are expected, but monolithic layer rupture is very hard to predict. In a past few years a practice of analyzing state of deformation in high energy seismic tremors zones has been employed. It let gathering experience thanks to witch determination of dangerous shape of reformatted roof is possible. In the paper some typical forms of roof rocks deformations leading to seismic tremor occurrence will be presented. In general these are various types of multidirectional rock layers bending. Real examples of seismic events and rock bursts in the Czech Republic will be shown. 5 refs., 6 figs.

Dome-shaped PDC cutters drill harder rock effectively

International Nuclear Information System (INIS)

Moran, D.P.

1992-01-01

This paper reports that rock mechanics and sonic travel time log data indicate that bits with convex-shaped polycrystalline diamond compact (PDC) cutters can drill harder rock formations than comparable bits with flat PDC cutters. The Dome-shaped cutters have drilled carbonate formations with sonic travel times as small as 50 μsec/ft, compared to the standard cutoff of 75 μsec/ft for flat PCD cutters. Recent field data from slim hole wells drilled in the Permian basin have shown successful applications of the 3/8-in. Dome cutter in the Grayburg dolomite with its sonic travel times as low as 50-55 μsec/ft and compressive strengths significantly greater than the standard operating range for PDC bit applications. These field data indicate that the Dome cutters can successfully drill hard rock. The convex cutter shape as good impact resistance, cuttings removal, heat dissipation, and wear resistance

Dynamic deformation and failure characteristic of rock foundation by means of effect of cyclic shear loading

International Nuclear Information System (INIS)

Fujiwara, Yoshikazu; Hibino, Satoshi; Kanagawa, Tadashi; Komada, Hiroya; Nakagawa, Kameichiro

1984-01-01

The main structures of nuclear power plants are built on hard and soft rocks. The rock-dynamic properties used for investigating the stability of the structures have been determined so far by laboratory tests for soft rocks. In hard rocks, however, joints and cracks exist, and the test including these effects is not able to be performed in laboratories at present. Therefore, a dynamic repeating shearing test equipment to be used under the condition including the joints and cracks of actual ground has been made for a base rock of tuff breccia. In this paper, the test results are reported as follows. The geological features of the testing site and the arrangement of tested rocks, the preparation for tests, test equipment, loading method, measuring method, analysis, and the result and the examination. The results of dynamic deformation and failure characteristics were as follows: (1) the dynamic shear-elasticity-modulus Gd of the base rock showed greater values as the normal stress increased, while Gd decreased and showed the strain dependence as the dynamic shear strain amplitude γ increased; (2) the relationship between Gd and γ was well represented with the equation proposed by Hardin-Drnevich; (3) damping ratio increased as γ increased, and decreased as normal stress increased; (4) When a specimen was about to break, γ suddenly increased, and the dynamic shear strain amplitude at yield point was in the range of approximately (3.4 to 4.1) x 10 -3 . (Wakatsuki, Y.)

Influence of Rock Mineralogy on Subsurface Water in Ado-Ekiti ...

African Journals Online (AJOL)

Nekky Umera

Physical test were carried out on hardness, colour, odour, conductivity, pH, and turbidity. Chemical test for sodium (Na+) and potassium (K2+) was also done using experimental scientific set standard. The analysis of the sodium, potassium ions, and the conductivity of the water indicate that dissolved mineral from rocks.

Quantitative Estimates of Bio-Remodeling on Coastal Rock Surfaces

Directory of Open Access Journals (Sweden)

Marta Pappalardo

2016-05-01

Full Text Available Remodeling of rocky coasts and erosion rates have been widely studied in past years, but not all the involved processes acting over rocks surface have been quantitatively evaluated yet. The first goal of this paper is to revise the different methodologies employed in the quantification of the effect of biotic agents on rocks exposed to coastal morphologic agents, comparing their efficiency. Secondly, we focus on geological methods to assess and quantify bio-remodeling, presenting some case studies in an area of the Mediterranean Sea in which different geological methods, inspired from the revised literature, have been tested in order to provide a quantitative assessment of the effects some biological covers exert over rocky platforms in tidal and supra-tidal environments. In particular, different experimental designs based on Schmidt hammer test results have been applied in order to estimate rock hardness related to different orders of littoral platforms and the bio-erosive/bio-protective role of Chthamalus ssp. and Verrucariaadriatica. All data collected have been analyzed using statistical tests to evaluate the significance of the measures and methodologies. The effectiveness of this approach is analyzed, and its limits are highlighted. In order to overcome the latter, a strategy combining geological and experimental–computational approaches is proposed, potentially capable of revealing novel clues on bio-erosion dynamics. An experimental-computational proposal, to assess the indirect effects of the biofilm coverage of rocky shores, is presented in this paper, focusing on the shear forces exerted during hydration-dehydration cycles. The results of computational modeling can be compared to experimental evidence, from nanoscopic to macroscopic scales.

Work Hard / Play Hard

OpenAIRE

Burrows, J.; Johnson, V.; Henckel, D.

2016-01-01

Work Hard / Play Hard was a participatory performance/workshop or CPD experience hosted by interdisciplinary arts atelier WeAreCodeX, in association with AntiUniversity.org. As a socially/economically engaged arts practice, Work Hard / Play Hard challenged employees/players to get playful, or go to work. 'The game changes you, you never change the game'. Employee PLAYER A 'The faster the better.' Employer PLAYER B

Convergent evidence for widespread rock nitrogen sources in Earth's surface environment.

Science.gov (United States)

Houlton, B Z; Morford, S L; Dahlgren, R A

2018-04-06

Nitrogen availability is a pivotal control on terrestrial carbon sequestration and global climate change. Historical and contemporary views assume that nitrogen enters Earth's land-surface ecosystems from the atmosphere. Here we demonstrate that bedrock is a nitrogen source that rivals atmospheric nitrogen inputs across major sectors of the global terrestrial environment. Evidence drawn from the planet's nitrogen balance, geochemical proxies, and our spatial weathering model reveal that ~19 to 31 teragrams of nitrogen are mobilized from near-surface rocks annually. About 11 to 18 teragrams of this nitrogen are chemically weathered in situ, thereby increasing the unmanaged (preindustrial) terrestrial nitrogen balance from 8 to 26%. These findings provide a global perspective to reconcile Earth's nitrogen budget, with implications for nutrient-driven controls over the terrestrial carbon sink. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Hard rock tunnel boring machine penetration test as an indicator of chipping process efficiency

Directory of Open Access Journals (Sweden)

M.C. Villeneuve

2017-08-01

Full Text Available The transition from grinding to chipping can be observed in tunnel boring machine (TBM penetration test data by plotting the penetration rate (distance/revolution against the net cutter thrust (force per cutter over the full range of penetration rates in the test. Correlating penetration test data to the geological and geomechanical characteristics of rock masses through which a penetration test is conducted provides the ability to reveal the efficiency of the chipping process in response to changing geological conditions. Penetration test data can also be used to identify stress-induced tunnel face instability. This research shows that the strength of the rock is an important parameter for controlling how much net cutter thrust is required to transition from grinding to chipping. It also shows that the geological characteristics of a rock will determine how efficient chipping occurs once it has begun. In particular, geological characteristics that lead to efficient fracture propagation, such as fabric and mica contents, will lead to efficient chipping. These findings will enable a better correlation between TBM performance and geological conditions for use in TBM design, as a basis for contractual payments where penetration rate dominates the excavation cycle and in further academic investigations into the TBM excavation process.

The Impact of Host Rock Geochemistry on Bacterial Community Structure in Oligotrophic Cave Environments.

Directory of Open Access Journals (Sweden)

Hazel A. Barton

2007-07-01

Full Text Available Despite extremely starved conditions, caves contain surprisingly diverse microbial communities. Our research is geared toward understanding what ecosystems drivers are responsible for this high diversity. To asses the effect of rock fabric and mineralogy, we carried out a comparative geomicrobiology study within Carlsbad Cavern, New Mexico, USA. Samples were collected from two different geologic locations within the cave: WF1 in the Massive Member of the Capitan Formation and sF88 in the calcareous siltstones of the Yates Formation. We examined the organic content at each location using liquid chromatography mass spectroscopy and analyzed microbial community structure using molecular phylogenetic analyses. In order to assess whether microbial activity was leading to changes in the bedrock at each location, the samples were also examined by petrology, X-ray diffraction (XRD and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX. Our results suggest that on the chemically complex Yates Formation (sF88, the microbial community was significantly more diverse than on the limestone surfaces of the Capitan (WF1, despite a higher total number of cells on the latter. Further, the broader diversity of bacterial species at sF88 reflected a larger range of potential metabolic capabilities, presumably due to opportunities to use ions within the rock as nutrients and for chemolithotrophic energy production. The use of these ions at sF88 is supported by the formation of a corrosion residue, presumably through microbial scavenging activities. Our results suggest that rock fabric and mineralogy may be an important driver of ecosystem function and should be carefully reviewed when carrying out microbial community analysis in cave environments.

Geotechnical properties of rock

Energy Technology Data Exchange (ETDEWEB)

Jackson, R.; Gorski, B.; Gyenge, M.

1995-12-31

The manual is a compilation of the geotechnical properties of many types of rock that are typical of Canadian mining environments. Included are values for density, porosity, compressive and shear wave velocity, uniaxial compressive strength, Young`s modulus, and Poisson`s ratio. The data base contains material constants that were determined using the Hoek and Brown failure criteria for both before and after failure conditions. 76 data sheets of rock properties in Canadian mines are included. 7 refs., 85 figs., 3 tabs.

Choosing between a rock and a hard place: Camouflage in the round-tailed horned lizard Phrynosoma modestum

Directory of Open Access Journals (Sweden)

William E. COOPER, Jr., Wade C. SHERBROOKE

2012-08-01

Full Text Available The round-tailed horned lizard Phrynosoma modestum is cryptically colored and resembles a small stone when it draws legs close to its body and elevates its back. We investigated effectiveness of camouflage in P. modestum and its dependence on stones by placing a lizard in one of two microhabitats (uniform sand or sand with surface rocks approximately the same size as lizards. An observer who knew which microhabitat contained the lizard was asked to locate the lizard visually. Latency to detection was longer and probability of no detection within 60 s was higher for lizards on rock background than on bare sand. In arenas where lizards could choose to occupy rock or bare sand, much higher proportions selected rocky backgrounds throughout the day; at night all lizards slept among stones. A unique posture gives P. modestum a rounded appearance similar to many natural stones. Lizards occasionally adopted the posture, but none did so in response to a nearby experimenter. Stimuli that elicit the posture are unknown. That P. modestum is better camouflaged among rocks than on bare sand and prefers to occupy rocky areas suggests that special resemblance to rocks (masquerade enhances camouflage attributable to coloration and immobility [Current Zoology 58 (4: 541–548, 2012].

Acoustic emission and ultrasonic-velocity methods used to characterise the excavation disturbance associated with deep tunnels in hard rock

Science.gov (United States)

Falls, Stephen D.; Young, R. Paul

1998-04-01

Acoustic emission (AE) and ultrasonic-velocity monitoring studies have been undertaken at both the Atomic Energy of Canada Limited (AECL) Underground Research Laboratory (URL) and at the Swedish Nuclear Fuel Waste Management Company (SKB) Hard Rock Laboratory (HRL). At both locations the excavations were tunnels in granitic material at approximately 420 m depth. However, the stress regime was more severe at the URL Mine-by tunnel site than the HRL ZEDEX tunnel. Different parts of the ZEDEX tunnel were created using different excavation techniques. Using AE and ultrasonic techniques to study these tunnels we have been able to examine the nature of the excavation-disturbed zone around the tunnel, as well as examining the effects of different stress regimes and excavation techniques. Studies were undertaken both during and after the Mine-by tunnel excavation and during excavation in the ZEDEX tunnel. AE monitoring in the wall of the Mine-by tunnel during excavation showed that some activity occurred in the sidewall regions, but the spatial density of AE hypocentres increased toward the regions in the floor and roof of the tunnel where breakout notches formed. This sidewall activity was clustered primarily within 0.5 m of the tunnel wall. AE monitoring in the floor of the tunnel showed that small numbers of AE continued to occur in the notch region in the floor of the tunnel over 2 years after excavation was completed. This activity became more acute as the rock was heated, imposing thermally induced stresses on the volume. Ultrasonic-velocity studies both in the floor and the wall of the tunnel showed that the velocity is strongly anisotropic with the direction of slowest velocity orthogonal to the tunnel surface. The velocity increased with distance into the rock from the tunnel surface. In the floor, this effect was seen up to 2 m from the tunnel surface. Most of the change occurred within the first 0.5 m from the tunnel perimeter. At the lower-stress HRL, most of

Material constitutive model for jointed rock mass behavior

International Nuclear Information System (INIS)

Thomas, R.K.

1980-11-01

A material constitutive model is presented for jointed rock masses which exhibit preferred planes of weakness. This model is intended for use in finite element computations. The immediate application is the thermomechanical modelling of a nuclear waste repository in hard rock, but the model seems appropriate for a variety of other static and dynamic geotechnical problems as well. Starting with the finite element representations of a two-dimensional elastic body, joint planes are introduced in an explicit manner by direct modification of the material stiffness matrix. A novel feature of this approach is that joint set orientations, lengths and spacings are readily assigned through the sampling of a population distribution statistically determined from field measurement data. The result is that the fracture characteristics of the formations have the same statistical distribution in the model as is observed in the field. As a demonstration of the jointed rock mass model, numerical results are presented for the example problem of stress concentration at an underground opening

Save or (over-)spend? : The impact of hard-discounter shopping on consumers' grocery outlay

NARCIS (Netherlands)

Gijsbrechts, Els; Campo, K.; Vroegrijk, M.J.J.

An increasing number of consumers have come to patronize a hard discounter (HD) to save on their grocery budget. Given the HDs' rock-bottom prices, a complete switch from the traditional supermarket (TS) to the HD format would, indeed, substantially reduce grocery spending. However, consumers

Environmental aspects of hard coal mines closure in Poland

International Nuclear Information System (INIS)

Chaber, M.; Krogulski, K.; Gawlik, L.

1998-01-01

The environmental problems that arise during the closure processes of hard coal mines in Poland are undertaken in the paper. The problems of changes in water balance in rock mass are described with a stress put on underground water management. Regulation concerning ground reclamation and utilisation and removal of existing heat and power plants which after the mines closure will continue to supply surrounding consumers are stressed and the possible solutions are shown. 13 refs

Diffusion in the matrix of granitic rock

International Nuclear Information System (INIS)

Birgersson, L.; Neretnieks, I.

1982-07-01

A migration experiment in the rock matrix is presented. The experiment has been carried out in undisturbed rock, that is rock under its natural stress environment. Since the experiment was performed at the 360 m-level (in the Stripa mine), the rock had nearly the same conditions as the rock surrounding a nuclear waste storage. The results show that all three tracers (Uranine, Cr-EDTA and I - ) have passed the disturbed zone from the injection hole and migrated into undisturbed rock. At the distance of 11 cm from the injection hole 5-10 percent of the injection concentration was found. The results also indicate that the tracer have passed through fissure filling material. These results indicate that it is possible for tracers (and therefore radionuclides) to migrate from a fissure, through fissure filling material, and into the undisturbed rock matrix. (Authors)

Carbonate rock depositional models: A microfacies approach

Energy Technology Data Exchange (ETDEWEB)

Carozzi, A.V.

1988-01-01

Carbonate rocks contain more than 50% by weight carbonate minerals such as calcite, dolomite, and siderite. Understanding how these rocks form can lead to more efficient methods of petroleum exploration. Micofacies analysis techniques can be used as a method of predicting models of sedimentation for carbonate rocks. Micofacies in carbonate rocks can be seen clearly only in thin sections under a microscope. This section analysis of carbonate rocks is a tool that can be used to understand depositional environments, diagenetic evolution of carbonate rocks, and the formation of porosity and permeability in carbonate rocks. The use of micofacies analysis techniques is applied to understanding the origin and formation of carbonate ramps, carbonate platforms, and carbonate slopes and basins. This book will be of interest to students and professionals concerned with the disciplines of sedimentary petrology, sedimentology, petroleum geology, and palentology.

Hard electronics; Hard electronics

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

Hard material technologies were surveyed to establish the hard electronic technology which offers superior characteristics under hard operational or environmental conditions as compared with conventional Si devices. The following technologies were separately surveyed: (1) The device and integration technologies of wide gap hard semiconductors such as SiC, diamond and nitride, (2) The technology of hard semiconductor devices for vacuum micro- electronics technology, and (3) The technology of hard new material devices for oxides. The formation technology of oxide thin films made remarkable progress after discovery of oxide superconductor materials, resulting in development of an atomic layer growth method and mist deposition method. This leading research is expected to solve such issues difficult to be easily realized by current Si technology as high-power, high-frequency and low-loss devices in power electronics, high temperature-proof and radiation-proof devices in ultimate electronics, and high-speed and dense- integrated devices in information electronics. 432 refs., 136 figs., 15 tabs.

Modelling of excavation depth and fractures in rock caused by tool indentation

International Nuclear Information System (INIS)

Kou Shaoquan; Tan Xiangchun; Lindqvist, P.A.

1997-10-01

The hydraulic regime after excavation in the near-field rock around deposition holes and deposition tunnels in a spent nuclear fuel repository is of concern for prediction of the saturation process of bentonite buffer and tunnel backfill. The hydraulic condition of main interest in this context is a result of the fracture network that is caused by the excavation. Modelling of the excavation disturbed zone in hard rocks caused by mechanical excavation has been carried out in the Division of Mining Engineering since 1993. This report contains an overview of the work conducted. The mechanical excavation is reasonably simplified as an indentation process of the interaction between rigid indenters and rocks. A large number of experiments have been carried out in the laboratory, and the results used for identifying crushed zones and fracture systems in rock under indentation are presented based on these experiments. The indentation causes crushing and damage of the rock and results in a crushed zone and a cracked zone. The indenter penetrates the rock with a certain depth when the force is over a threshold value relevant to the rock and tool. Outside the cracked zone there are basically three systems of cracks: median cracks, radial cracks, and side cracks. Fully developed radial cracks on each side of the indented area can connect with each other and join with median crack. This forms the so-called radial/median crack system. The influence of the mechanical properties of the rock is discussed based on our conceptual model, and the main factors governing the indentation event are summarised. The cracked zone is dealt with by an analytical fracture model. The side crack is simulated by applying the boundary element method coupled with fracture mechanics. Functional relationships are established relating either the indentation depth or the length of radial/median cracks to the various quantities characterising the physical event, namely the shape and the size of the

Modelling of excavation depth and fractures in rock caused by tool indentation

Energy Technology Data Exchange (ETDEWEB)

Kou Shaoquan; Tan Xiangchun; Lindqvist, P.A. [Luleaa Univ. of Technology (Sweden)

1997-10-01

The hydraulic regime after excavation in the near-field rock around deposition holes and deposition tunnels in a spent nuclear fuel repository is of concern for prediction of the saturation process of bentonite buffer and tunnel backfill. The hydraulic condition of main interest in this context is a result of the fracture network that is caused by the excavation. Modelling of the excavation disturbed zone in hard rocks caused by mechanical excavation has been carried out in the Division of Mining Engineering since 1993. This report contains an overview of the work conducted. The mechanical excavation is reasonably simplified as an indentation process of the interaction between rigid indenters and rocks. A large number of experiments have been carried out in the laboratory, and the results used for identifying crushed zones and fracture systems in rock under indentation are presented based on these experiments. The indentation causes crushing and damage of the rock and results in a crushed zone and a cracked zone. The indenter penetrates the rock with a certain depth when the force is over a threshold value relevant to the rock and tool. Outside the cracked zone there are basically three systems of cracks: median cracks, radial cracks, and side cracks. Fully developed radial cracks on each side of the indented area can connect with each other and join with median crack. This forms the so-called radial/median crack system. The influence of the mechanical properties of the rock is discussed based on our conceptual model, and the main factors governing the indentation event are summarised. The cracked zone is dealt with by an analytical fracture model. The side crack is simulated by applying the boundary element method coupled with fracture mechanics. Functional relationships are established relating either the indentation depth or the length of radial/median cracks to the various quantities characterising the physical event, namely the shape and the size of the

Paradise regained: older adult rock climbers turning space into place in the natural environment

Directory of Open Access Journals (Sweden)

Mark Hickman

2015-12-01

Full Text Available At the time of writing there are over 10 million people aged over 65 living in the UK, and by 2050 the number is predicted to rise to 19 million. This expansion of the ageing population is mirrored worldwide, and over the past ten years has stimulated a growth in age-related studies. However, the idea of a social gerontology of the outdoors is yet to take root. Yet, with the maturing of those born between the years 1946 and 1964, and increased participation in adventurous activities, we suggest that the time is right for scholarship in this specific direction. Accordingly, the aim of this study was to discover how older adult rock climbers perceived their relationship with the natural environment to have changed over the period of their involvement with rock climbing. The investigation used a purposive sample of rock climbers in the north-west of England (n=10 aged between 65 and 74 years (av=69.6 identifying them as ‘young-old’ adults. Oral testimony was collected over two phases, the first with interview-questionnaires, and the second with targeted semi-structured interviews. In order to give a clear voice to participants, manual data handling using was used to establish raw data that were then sorted into themes and verified against internal and external checkers. These were then organized around Peace, Wahl, Mollenkopf and Oswald’s (2014 concept of an ‘environment’ considered within three dimensions: the physical/material, including the natural landscape; the psychological, and the meaning attributed to the place, its evolution across the life course, and how it makes people feel about themselves; and the social/cultural, involving the engagement of people to places, including how the space is used and remembered.

Strengthening carbonate roof rock of workings by the use of resins in Karst disturbance zones

Energy Technology Data Exchange (ETDEWEB)

Timofeev, O.V.; Gerovich, E.G.

1977-12-01

Test results are given for a proposed method of injection strengthening of rock in sinkhole areas in order to stabilize the rock of mining areas. Tests were made of appropriately selected NaOH solutions to act as catalysts in the injection of resins. Relationships are given between the hardening time of the aqueous resin solutions and the concentration of the NaOH catalyst, the relationship between the viscosity of the resin solutions and the temperature at specific ratios, between the hardness of the polymer materials and age, and between the resinous mixture compression strength and its age at specific temperatures. A diagram is presented of the injection equipment, and data are presented on the number of boreholes receiving the injected resin in relation to physical measurements. The tests of the resinated areas indicate that the rock hardness of the treated zones approaches that of the fissured zones so that props with less supporting power can be used, and work safety is increased. 3 references, 6 figures, 1 table.

Introduction to numerical modeling of thermohydrologic flow in fractured rock masses

International Nuclear Information System (INIS)

Wang, J.S.Y.

1980-01-01

More attention is being given to the possibility of nuclear waste isolation in hard rock formations. The waste will generate heat which raises the temperature of the surrounding fractured rock masses and induces buoyancy flow and pressure change in the fluid. These effects introduce the potential hazard of radionuclides being carried to the biosphere, and affect the structure of a repository by stress changes in the rock formation. The thermohydrological and thermomechanical responses are determined by the fractures as well as the intact rock blocks. The capability of modeling fractured rock masses is essential to site characterization and repository evaluation. The fractures can be modeled either as a discrete system, taking into account the detailed fracture distributions, or as a continuum representing the spatial average of the fractures. A numerical model is characterized by the governing equations, the numerical methods, the computer codes, the validations, and the applications. These elements of the thermohydrological models are discussed. Along with the general review, some of the considerations in modeling fractures are also discussed. Some remarks on the research needs in modeling fractured rock mass conclude the paper

40 CFR 422.40 - Applicability; description of the defluorinated phosphate rock subcategory.

Science.gov (United States)

2010-07-01

... defluorinated phosphate rock subcategory. 422.40 Section 422.40 Protection of Environment ENVIRONMENTAL... Defluorinated Phosphate Rock Subcategory § 422.40 Applicability; description of the defluorinated phosphate rock... phosphate rock by application of high temperature treatment along with wet process phosphoric acid, silica...

SITE-94. Geochemical characterization of Simpevarp ground waters near the Aespoe Hard Rock Laboratory

International Nuclear Information System (INIS)

Glynn, P.D.; Voss, C.I.

1999-09-01

The present report analyzes the geochemical data in order to evaluate collection and interpretation techniques that will be used to site the repository and to assess its safety. Ground waters near the Aespoe Hard Rock Laboratory (HRL) may be grouped into five chemically and isotopically distinct water types, on the basis of their deuterium and chloride contents: 1) recent waters, 2) 5 g/L chloride waters, 3) deep waters, 4) seawater imprint waters, and 5) glacial melt waters. The sampled ground waters show a progressive change from a predominantly NaHCO 3 composition at shallow depth to a CaCl 2 -rich composition at depth. Despite the proximity of the Baltic, relatively few of the sampled ground waters contain any evidence of a seawater component. This finding, together with the rather shallow depths at which saline waters were found, indicates that Aespoe island is presently in a regional ground-water discharge area. The chemical and isotopic composition of the sampled waters also indicates that local recharge of dilute recent waters occurs only down to shallow depths (generally less than 100 in). The Aespoe ground waters are sulfidic and do not presently contain any dissolved oxygen. Measured E H values are generally near -300 mV, and on average are only about 50 mV lower than E H values calculated from the sulfide/sulfate couple. Maintenance of reducing conditions, such as presently found at the Aespoe HRL, is an important consideration in assessing the performance of nuclear waste disposal sites. Measurements of dissolved radon and of uranium concentrations in fracture-fill materials were used to calculate an average effective flow-wetted surface area of 3.1 m 2 per liter of water for the Aespoe site. Estimation of flow-wetted surface areas is essential in determining the importance of matrix diffusion and surface sorption processes for radionuclide release calculations. The Rn calculation technique shows promise in helping narrow the possible range of values

Site investigations: Strategy for rock mechanics site descriptive model

International Nuclear Information System (INIS)

Andersson, Johan; Christiansson, Rolf; Hudson, John

2002-05-01

As a part of the planning work for the Site Investigations, SKB has developed a Rock Mechanics Site Descriptive Modelling Strategy. Similar strategies are being developed for other disciplines. The objective of the strategy is that it should guide the practical implementation of evaluating site specific data during the Site Investigations. It is also understood that further development may be needed. This methodology enables the crystalline rock mass to be characterised in terms of the quality at different sites, for considering rock engineering constructability, and for providing the input to numerical models and performance assessment calculations. The model describes the initial stresses and the distribution of deformation and strength properties of the intact rock, of fractures and fracture zones, and of the rock mass. The rock mass mechanical properties are estimated by empirical relations and by numerical simulations. The methodology is based on estimation of mechanical properties using both empirical and heroretical/numerical approaches; and estimation of in situ rock stress using judgement and numerical modelling, including the influence of fracture zones. These approaches are initially used separately, and then combined to produce the required characterisation estimates. The methodology was evaluated with a Test Case at the Aespoe Hard Rock Laboratory in Sweden. The quality control aspects are an important feature of the methodology: these include Protocols to ensure the structure and coherence of the procedures used, regular meetings to enhance communication, feedback from internal and external reviewing, plus the recording of an audit trail of the development steps and decisions made. The strategy will be reviewed and, if required, updated as appropriate

Site investigations: Strategy for rock mechanics site descriptive model

Energy Technology Data Exchange (ETDEWEB)

Andersson, Johan [JA Streamflow AB, Aelvsjoe (Sweden); Christiansson, Rolf [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Hudson, John [Rock Engineering Consultants, Welwyn Garden City (United Kingdom)

2002-05-01

As a part of the planning work for the Site Investigations, SKB has developed a Rock Mechanics Site Descriptive Modelling Strategy. Similar strategies are being developed for other disciplines. The objective of the strategy is that it should guide the practical implementation of evaluating site specific data during the Site Investigations. It is also understood that further development may be needed. This methodology enables the crystalline rock mass to be characterised in terms of the quality at different sites, for considering rock engineering constructability, and for providing the input to numerical models and performance assessment calculations. The model describes the initial stresses and the distribution of deformation and strength properties of the intact rock, of fractures and fracture zones, and of the rock mass. The rock mass mechanical properties are estimated by empirical relations and by numerical simulations. The methodology is based on estimation of mechanical properties using both empirical and heroretical/numerical approaches; and estimation of in situ rock stress using judgement and numerical modelling, including the influence of fracture zones. These approaches are initially used separately, and then combined to produce the required characterisation estimates. The methodology was evaluated with a Test Case at the Aespoe Hard Rock Laboratory in Sweden. The quality control aspects are an important feature of the methodology: these include Protocols to ensure the structure and coherence of the procedures used, regular meetings to enhance communication, feedback from internal and external reviewing, plus the recording of an audit trail of the development steps and decisions made. The strategy will be reviewed and, if required, updated as appropriate.

Rock Directed Breaking Under the Impulse Load

Science.gov (United States)

Khomeriki, Sergo; Mataradze, Edgar; Chikhradze, Nikoloz; Losaberidze, Marine; Khomeriki, Davit; Shatberashvili, Grigol

2016-10-01

In the work the problem of directed chipping of facing stone material by means of managing of explosion process is considered. The technology of the mining of decorative stone by the use of explosion energy means the very rapid transfer of potential energy of elastic deformations to kinetic energy. As a result, the explosion impulse, in the expanse of the inertia of rock massive, does not cause the increase of existing cracks. In the course of explosion, the shock wave is propagated by ultrasonic velocity and in this case the medium parameters (pressure, density, temperature, velocity) increase in spurts. In spite of this fact the all three conservation laws of mechanics remain valid on basis of three laws the equations are derived by which the parameters of shock wave may be defined by means of the rock physical-mechanical properties. The load on the body volume at breaking under explosion acts over very small period of the time. Therefore, stressed-deformed state of the rock was studied when the impulse load acts on the boundary. It was considered that the mining of the blocks of facing stone is performed from the hard rocks. This means that the breaking proceeds in the zone of elastic deformation. In the conditions of mentioned assumptions, the expression of the stress tensor and displacement of vector components initiated by stressed-deformed state in the rock are written.

VIRTUAL HERITAGE ARCHIVES: BUILDING A CENTRALIZED AUSTRALIAN ROCK ART ARCHIVE

Directory of Open Access Journals (Sweden)

R. A. Haubt

2013-07-01

Full Text Available This paper examines use of multi-media in the curation, presentation and promotion of rock art. It discusses the construction of a centralised Australian rock art database and explores new technologies available for looking at rock art. In 2011, Prof. Taçon Chair in Rock Art Research and Director of PERAHU (Place, Evolution and Rock Art Heritage Unit called for a national rock art database raising awareness of the importance of preserving rock art as part of Australia's valuable Indigenous heritage (Taçon, 2011. Australia has over 100,000 rock art sites, important heritage places for Indigenous and non-Indigenous Australians and a testament to over 10,000 years of human activity, including interactions with other peoples and the environment. Many of these sites have not been documented or recorded and are threatened by natural and cultural agents. It is becoming increasingly important to develop conservation models for the protection and preservation of sites. Indigenous cultural heritage is difficult to manage on a local government level due to complex human / time / environment relationships and the importance of intangible cultural heritage (SoE SEWPAC, 2011. Currently no centralised database system exists in Australia to curate, present and promote rock art.

Modelling the effect of diffusion into the rock matrix on radionuclide migration

International Nuclear Information System (INIS)

Lever, D.A.; Bradbury, M.H.; Hemingway, S.J.

1983-01-01

Diffusion into the rock matrix is potentially an important retardation mechanism for nuclides leached from an underground radioactive waste repository in a fractured hard rock. Models of this diffusion process are discussed and incorporated into three-dimensional radionuclide migration models. Simple solutions to these models are derived for two regions: the region near to the repository where the nuclide is diffusing into effectively infinite rock, and that much further downstream where the concentrations in the rock and fractures are almost in equilibrium. These solutions are used to evaluate the possible impact on migration. It is shown that retardation factors in excess of 100 and reductions in the peak concentration at a given point on the flow path by three or four orders of magnitude are possibe for non-sorbed ions, which would otherwise be carried by the flow and not retarded at all. (author)

Boring of full scale deposition holes at the Aespoe Hard Rock Laboratory. Operational experiences including boring performance and a work time analysis

Energy Technology Data Exchange (ETDEWEB)

Andersson, Christer [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Johansson, Aasa [SWECO, Stockholm (Sweden)

2002-12-01

Thirteen experimental deposition holes similar to those in the present KBS-3 design have been bored at the Aespoe Hard Rock Laboratory, Oskarshamn, Sweden. The objective with the boring program was to test and demonstrate the current technique for boring of large vertical holes in granitic rock. Conclusions and results from this project is used in the planning process for the deposition holes that will be bored in the real repository for spent nuclear fuel. The boreholes are also important for three major projects. The Prototype Repository, the Canister Retrieval Test and the Demonstration project will all need full-scale deposition holes for their commissioning. The holes are bored in full scale and have a radius of 1.75 m and a depth of 8.5 m. To bore the holes an existing TBM design was modified to produce a novel type Shaft Boring Machine (SBM) suitable for boring 1.75 m diameter holes from a relatively small tunnel. The cutter head was equipped with two types of roller cutters: two row carbide button cutters and disc cutters. Removal of the cuttings was made with a vacuum suction system. The boring was monitored and boring parameters recorded by a computerised system for the evaluation of the boring performance. During boring of four of the holes temperature, stress and strain measurements were performed. Acoustic emission measurements were also performed during boring of these four holes. The results of these activities will not be discussed in this report since they are reported separately. Criteria regarding nominal borehole diameter, deviation of start and end centre point, surface roughness and performance of the machine were set up according to the KBS-3 design and were fulfilled with a fair margin. The average total time for boring one deposition hole during this project was 105 hours.

Boring of full scale deposition holes at the Aespoe Hard Rock Laboratory. Operational experiences including boring performance and a work time analysis

International Nuclear Information System (INIS)

Andersson, Christer; Johansson, Aasa

2002-12-01

Thirteen experimental deposition holes similar to those in the present KBS-3 design have been bored at the Aespoe Hard Rock Laboratory, Oskarshamn, Sweden. The objective with the boring program was to test and demonstrate the current technique for boring of large vertical holes in granitic rock. Conclusions and results from this project is used in the planning process for the deposition holes that will be bored in the real repository for spent nuclear fuel. The boreholes are also important for three major projects. The Prototype Repository, the Canister Retrieval Test and the Demonstration project will all need full-scale deposition holes for their commissioning. The holes are bored in full scale and have a radius of 1.75 m and a depth of 8.5 m. To bore the holes an existing TBM design was modified to produce a novel type Shaft Boring Machine (SBM) suitable for boring 1.75 m diameter holes from a relatively small tunnel. The cutter head was equipped with two types of roller cutters: two row carbide button cutters and disc cutters. Removal of the cuttings was made with a vacuum suction system. The boring was monitored and boring parameters recorded by a computerised system for the evaluation of the boring performance. During boring of four of the holes temperature, stress and strain measurements were performed. Acoustic emission measurements were also performed during boring of these four holes. The results of these activities will not be discussed in this report since they are reported separately. Criteria regarding nominal borehole diameter, deviation of start and end centre point, surface roughness and performance of the machine were set up according to the KBS-3 design and were fulfilled with a fair margin. The average total time for boring one deposition hole during this project was 105 hours

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

Directory of Open Access Journals (Sweden)

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.

Surface-groundwater interactions in hard rocks in Sardon Catchment of western Spain: an integrated modeling approach

Science.gov (United States)

Hassan, S.M. Tanvir; Lubczynski, Maciek W.; Niswonger, Richard G.; Zhongbo, Su

2014-01-01

The structural and hydrological complexity of hard rock systems (HRSs) affects dynamics of surface–groundwater interactions. These complexities are not well described or understood by hydrogeologists because simplified analyses typically are used to study HRSs. A transient, integrated hydrologic model (IHM) GSFLOW (Groundwater and Surface water FLOW) was calibrated and post-audited using 18 years of daily groundwater head and stream discharge data to evaluate the surface–groundwater interactions in semi-arid, ∼80 km2 granitic Sardon hilly catchment in Spain characterized by shallow water table conditions, relatively low storage, dense drainage networks and frequent, high intensity rainfall. The following hydrological observations for the Sardon Catchment, and more generally for HRSs were made: (i) significant bi-directional vertical flows occur between surface water and groundwater throughout the HRSs; (ii) relatively large groundwater recharge represents 16% of precipitation (P, 562 mm.y−1) and large groundwater exfiltration (∼11% of P) results in short groundwater flow paths due to a dense network of streams, low permeability and hilly topographic relief; deep, long groundwater flow paths constitute a smaller component of the water budget (∼1% of P); quite high groundwater evapotranspiration (∼5% of P and ∼7% of total evapotranspiration); low permeability and shallow soils are the main reasons for relatively large components of Hortonian flow and interflow (15% and 11% of P, respectively); (iii) the majority of drainage from the catchment leaves as surface water; (iv) declining 18 years trend (4.44 mm.y−1) of groundwater storage; and (v) large spatio-temporal variability of water fluxes. This IHM study of HRSs provides greater understanding of these relatively unknown hydrologic systems that are widespread throughout the world and are important for water resources in many regions.

Igneous Rocks

Science.gov (United States)

Doe, Bruce R.

“Igneous Rocks was written for undergraduate geology majors who have had a year of college-level chemistry and a course in mineralogy … and for beginning graduate students. Geologists working in industry, government, or academia should find this text useful as a guide to the technical literature up to 1981 and as an overview of topics with which they have not worked but which may have unanticipated pertinence to their own projects.” So starts the preface to this textbook.As one who works part time in research on igneous rocks, especially as they relate to mineral deposits, I have been looking for such a book with this avowed purpose in a field that has a choking richness of evolving terminology and a bewildering volume of interdisciplinary literature. In addition to the standard topics of igneous petrology, the book contains a chapter on the role of igneous activity in the genesis of mineral deposits, its value to geothermal energy, and the potential of igneous rocks as an environment for nuclear waste disposal. These topics are presented rather apologetically in the preface, but the author is to be applauded for including this chapter. The apology shows just how new these interests are to petrology. Recognition is finally coming that, for example, mineral deposits are not “sports of nature,” a view held even by many economic geologists as recently as the early 1960's; instead they are perfectly ordinary geochemical features formed by perfectly ordinary geologic processes. In fact, the mineral deposits and their attendant alteration zones probably have as much to tell us about igneous rocks as the igneous rocks have to tell us about mineral deposits.

Disposal of radioactive waste in Swedish crystalline rocks

International Nuclear Information System (INIS)

Greis Dahlberg, Christina; Wikberg, Peter

2015-01-01

SKB, Swedish Nuclear Fuel and Waste Management Company is tasked with managing Swedish nuclear and radioactive waste. Crystalline rock is the obvious alternative for deep geological disposal in Sweden. SKB is, since 1988, operating a near surface repository for short-lived low and intermediate-level waste, SFR. The waste in SFR comprises operational and decommissioning waste from nuclear plants, industrial waste, research-related waste and medical waste. Spent nuclear fuel is currently stored in an interim facility while waiting for a license to construct a deep geological repository. The Swedish long-lived low and intermediate-level waste consists mainly of BWR control rods, reactor internals and legacy waste from early research in the Swedish nuclear programs. The current plan is to dispose of this waste in a separate deep geological repository, SFL, sometimes after 2045. Understanding of the rock properties is the basis for the design of the repository concepts. Swedish crystalline rock is mechanical stable and suitable for underground constructions. The Spent Fuel Repository is planned at approximately 500 meters depth in the rock at the Forsmark site. The host rock will keep the spent fuel isolated from human and near-surface environment. The rock will also provide the stable chemical and hydraulic conditions that make it possible to select suitable technical barriers to support the containment provided by the rock. A very long lasting canister is necessary to avoid release and transport of radionuclides through water conducting fractures in the rock. A canister designed for the Swedish rock, consists of a tight, 5 cm thick corrosion barrier of copper and a load-bearing insert of cast iron. To restrict the water flow around the canister and by that prevent fast corrosion, a bentonite buffer will surround the canister. Secondary, the bentonite buffer will retard a potential release by its strong sorption of radionuclides. The SFR repository is situated in

Disposal of radioactive waste in Swedish crystalline rocks

Energy Technology Data Exchange (ETDEWEB)

Greis Dahlberg, Christina; Wikberg, Peter [Svensk Kaernbraenslehantering AB, Stockholm (Sweden)

2015-07-01

SKB, Swedish Nuclear Fuel and Waste Management Company is tasked with managing Swedish nuclear and radioactive waste. Crystalline rock is the obvious alternative for deep geological disposal in Sweden. SKB is, since 1988, operating a near surface repository for short-lived low and intermediate-level waste, SFR. The waste in SFR comprises operational and decommissioning waste from nuclear plants, industrial waste, research-related waste and medical waste. Spent nuclear fuel is currently stored in an interim facility while waiting for a license to construct a deep geological repository. The Swedish long-lived low and intermediate-level waste consists mainly of BWR control rods, reactor internals and legacy waste from early research in the Swedish nuclear programs. The current plan is to dispose of this waste in a separate deep geological repository, SFL, sometimes after 2045. Understanding of the rock properties is the basis for the design of the repository concepts. Swedish crystalline rock is mechanical stable and suitable for underground constructions. The Spent Fuel Repository is planned at approximately 500 meters depth in the rock at the Forsmark site. The host rock will keep the spent fuel isolated from human and near-surface environment. The rock will also provide the stable chemical and hydraulic conditions that make it possible to select suitable technical barriers to support the containment provided by the rock. A very long lasting canister is necessary to avoid release and transport of radionuclides through water conducting fractures in the rock. A canister designed for the Swedish rock, consists of a tight, 5 cm thick corrosion barrier of copper and a load-bearing insert of cast iron. To restrict the water flow around the canister and by that prevent fast corrosion, a bentonite buffer will surround the canister. Secondary, the bentonite buffer will retard a potential release by its strong sorption of radionuclides. The SFR repository is situated in

Site Classification using Multichannel Channel Analysis of Surface Wave (MASW) method on Soft and Hard Ground

Science.gov (United States)

Ashraf, M. A. M.; Kumar, N. S.; Yusoh, R.; Hazreek, Z. A. M.; Aziman, M.

2018-04-01

Site classification utilizing average shear wave velocity (Vs(30) up to 30 meters depth is a typical parameter. Numerous geophysical methods have been proposed for estimation of shear wave velocity by utilizing assortment of testing configuration, processing method, and inversion algorithm. Multichannel Analysis of Surface Wave (MASW) method is been rehearsed by numerous specialist and professional to geotechnical engineering for local site characterization and classification. This study aims to determine the site classification on soft and hard ground using MASW method. The subsurface classification was made utilizing National Earthquake Hazards Reduction Program (NERHP) and international Building Code (IBC) classification. Two sites are chosen to acquire the shear wave velocity which is in the state of Pulau Pinang for soft soil and Perlis for hard rock. Results recommend that MASW technique can be utilized to spatially calculate the distribution of shear wave velocity (Vs(30)) in soil and rock to characterize areas.

Rock cavern storage of spent fuel

Energy Technology Data Exchange (ETDEWEB)

Cho, Won Jin; Kim, Kyung Soo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kwon, Sang Ki [Inha University, Incheon (Korea, Republic of)

2015-12-15

The rock cavern storage for spent fuel has been assessed to apply in Korea with reviewing the state of the art of the technologies for surface storage and rock cavern storage of spent fuel. The technical feasibility and economic aspects of the rock cavern storage of spent fuel were also analyzed. A considerable area of flat land isolated from the exterior are needed to meet the requirement for the site of the surface storage facilities. It may, however, not be easy to secure such areas in the mountainous region of Korea. Instead, the spent fuel storage facilities constructed in the rock cavern moderate their demands for the suitable site. As a result, the rock cavern storage is a promising alternative for the storage of spent fuel in the aspect of natural and social environments. The rock cavern storage of spent fuel has several advantages compared with the surface storage, and there is no significant difference on the viewpoint of economy between the two alternatives. In addition, no great technical difficulties are present to apply the rock cavern storage technologies to the storage of domestic spent fuel.

Radionuclide fixation mechanisms in rocks

International Nuclear Information System (INIS)

Nakashima, S.

1991-01-01

In the safety evaluation of the radioactive waste disposal in geological environment, the mass balance equation for radionuclide migration is given. The sorption of radionuclides by geological formations is conventionally represented by the retardation of the radionuclides as compared with water movement. In order to quantify the sorption of radionuclides by rocks and sediments, the distribution ratio is used. In order to study quantitatively the long term behavior of waste radionuclides in geological environment, besides the distribution ratio concept in short term, slower radionuclide retention reaction involving mineral transformation should be considered. The development of microspectroscopic method for long term reaction path modeling, the behavior of iron during granite and water interaction, the reduction precipitation of radionuclides, radionuclide migration pathways, and the representative scheme of radionuclide migration and fixation in rocks are discussed. (K.I.)

Depositional environments, provenance and paleoclimatic implications of Ordovician siliciclastic rocks of the Thango Formation, Spiti Valley, Tethys Himalaya, northern India

Science.gov (United States)

Rashid, Shaik A.; Ganai, Javid A.

2018-05-01

Recently published findings indicate that the Ordovician period has been much more dynamic than previously anticipated thus making this period significant in geological time. The Ordovician of India can best be studied in the Spiti region because the Spiti basin records the complete uninterrupted history of excellent marine sedimentary rocks starting from Cambrian to Paleogene which were deposited along the northern margin of India. Due to these reasons the geochemical data on the Ordovician rocks from the Spiti region is uncommon. The present geochemical study on the Ordovician Thango Formation (Sanugba Group) is mainly aimed to understand the provenance and the paleoclimatic conditions. The sandstones are the dominant lithology of the Thango Formation with intercalations of minor amount of shales. Detailed petrographic and sedimentological analysis of these rocks suggest that three major depositional environments, viz., fluvial, transitional and marine prevailed in the basin representing transgressive and regressive phases. The major and trace element ratios such as SiO2/Al2O3, K2O/Na2O and La-Th- Sc discrimination diagram suggest that these rocks were deposited in passive margin tectonic settings. Various geochemical discriminants and elemental ratios such as K2O/Na2O, Al2O3/TiO2, La/Sc, Th/Sc, Cr/Th, Zr/Sc, (Gd/Yb)N and pronounced negative Eu anomalies indicate the rocks to be the product of weathering of post-Archean granites. The striking similarities of the multi-elemental spider diagrams of the studied sediments and the Himalayan granitoids indicate that sediments are sourced from the Proterozoic orogenic belts of the Himalayan region. Chemical index of alteration (CIA) values of the studied sediments (55-72) suggest that the source rocks underwent low to moderate degree of chemical weathering. The span of the CIA values (55-72) recorded in the sediments from the Spiti region may have resulted from varying degrees of weathering conditions in the source area

No Reprieve for Tasmanian Rock Art

Directory of Open Access Journals (Sweden)

Peter C. Sims

2013-10-01

Full Text Available The Australian State of Tasmania, at latitude 42 degrees south, became an island about 8,000 years ago when the sea rose to its present level, following the melting of polar and glacial ice that covered much of the land mass. After that time, the Tasmanian Aboriginal rock art developed independently of mainland Australia, with its form being basically linear with some naturalistic figures and a predominance of cupules. The petroglyphs with one lithophone site occur on various rock substrates varying in hardness from granite to sandstone. Many sites exist along the western coastline that borders the Southern Ocean where the landscape in some places has changed little since the arrival of Europeans in 1803. The significance of this Tasmanian Aboriginal cultural heritage along what is now known as the Tarkine Coast, named after an Aboriginal band that once inhabited this area, was recognised by the Australian Government in February 2013 when a 21,000 ha strip, 2 km wide, was inscribed on its National Heritage Register, being one of 98 special places listed in the country. However, politics and racism hamper its management. This paper is based on the results of 40 years of field recording of the Tasmanian Aboriginal rock art sites, many of which remain unpublished.

Numerical Analyses of the Influence of Blast-Induced Damaged Rock Around Shallow Tunnels in Brittle Rock

Science.gov (United States)

Saiang, David; Nordlund, Erling

2009-06-01

Most of the railway tunnels in Sweden are shallow-seated (rock cover) and are located in hard brittle rock masses. The majority of these tunnels are excavated by drilling and blasting, which, consequently, result in the development of a blast-induced damaged zone around the tunnel boundary. Theoretically, the presence of this zone, with its reduced strength and stiffness, will affect the overall performance of the tunnel, as well as its construction and maintenance. The Swedish Railroad Administration, therefore, uses a set of guidelines based on peak particle velocity models and perimeter blasting to regulate the extent of damage due to blasting. However, the real effects of the damage caused by blasting around a shallow tunnel and their criticality to the overall performance of the tunnel are yet to be quantified and, therefore, remain the subject of research and investigation. This paper presents a numerical parametric study of blast-induced damage in rock. By varying the strength and stiffness of the blast-induced damaged zone and other relevant parameters, the near-field rock mass response was evaluated in terms of the effects on induced boundary stresses and ground deformation. The continuum method of numerical analysis was used. The input parameters, particularly those relating to strength and stiffness, were estimated using a systematic approach related to the fact that, at shallow depths, the stress and geologic conditions may be highly anisotropic. Due to the lack of data on the post-failure characteristics of the rock mass, the traditional Mohr-Coulomb yield criterion was assumed and used. The results clearly indicate that, as expected, the presence of the blast-induced damage zone does affect the behaviour of the boundary stresses and ground deformation. Potential failure types occurring around the tunnel boundary and their mechanisms have also been identified.

Hydrologic properties of shale and related argillaceous rocks

International Nuclear Information System (INIS)

Moiseyev, A.N.

1979-01-01

This report is the result of a bibliographic study designed primarily to collect hydrologic data on American clay-rich rocks. The following information was also sought: stratigraphy, environment of deposition, mineralogic composition, and diagenetic changes. The collected numerical data are presented in tables which contain densities, porosities, and/or hydraulic conductivities of approximately 360 samples. Additional data include hydraulic diffusivities, resistivities, flow rates, and rock strengths. Geologic information suggests that large deposits of shale which may be suited for waste repository belong to all ages and were formed in both marine and continental environments. Of the studied units, the most promising are Paleozoic in the eastern half of the country, Mesozoic in the central part, and Cenozoic in the Gulf Coast area and the West. Less widespread units locally present some additional possibilities. Mineralogic investigations suggest that the smectite content in rocks shows a decrease in time (70% in Recent rocks; 35% in pre-Mesozoic rocks). Because of this predominance of smectite in younger rocks, the modeling of repositories in post-Paleozoic formations might require knowledge of additional and poorly known parameters. Results of investigations into the mathematical relationships between porosity and permeability (or hydralic conductivity) suggest that in situ permeabilities could be estimated from sonic logs and fluid pressure changes at depth. 16 figures, 8 tables

Granite-repository - geochemical environment

International Nuclear Information System (INIS)

1979-04-01

Some geochemical data of importance for a radioactive waste repository in hard rock are reviewed. The ground water composition at depth is assessed. The ground water chemistry in the vicinity of uranium ores is discussed. The redox system in Swedish bedrock is described. Influences of extreme climatic changes and of repository mining and construction are also evaluated

Theoretical Investigations on the Influence of Artificially Altered Rock Mass Properties on Mechanical Excavation

Science.gov (United States)

Hartlieb, Philipp; Bock, Stefan

2018-03-01

This study presents a theoretical analysis of the influence of the rock mass rating on the cutting performance of roadheaders. Existing performance prediction models are assessed for their suitability for forecasting the influence of pre-damaging the rock mass with alternative methods like lasers or microwaves, prior to the mechanical excavation process. Finally, the RMCR model was chosen because it is the only reported model incorporating a range of rock mass properties into its calculations. The results show that even very tough rocks could be mechanically excavated if the occurrence, orientation and condition of joints are favourable for the cutting process. The calculated improvements in the cutting rate (m3/h) are up to 350% for the most favourable cases. In case of microwave irradiation of hard rocks with an UCS of 200 MPa, a reasonable improvement in the performance by 120% can be achieved with as little as an extra 0.7 kWh/m3 (= 1% more energy) compared to cutting only.

Aespoe Hard Rock Laboratory. Prototype Repository. Sensors data report (Period 010917-091201) Report No: 22

International Nuclear Information System (INIS)

Goudarzi, Reza; Johannesson, Lars-Erik

2009-12-01

The Prototype Repository Test consists of two sections. The installation of the first Section of Prototype Repository was made during summer and autumn 2001 and Section 2 was installed in spring and summer 2003. This report presents data from measurements in the Prototype Repository during the period 010917-091201. The report is organized so that the actual measured results are shown in Appendix 1-10, where Appendix 8 deals with measurements of canister displacements (by AITEMIN), Appendix 9 deals with geo-electric measurements in the backfill (by GRS), Appendix 10 deals with stress and strain measurement in the rock (by AaF) and Appendix 11 deals with measurement of water pressure in the rock (by VBB/VIAK). The main report and Appendix 1-7 deal with the rest of the measurements

Aespoe Hard Rock Laboratory. Prototype Repository. Sensors data report (Period 010917-090601) Report No: 21

International Nuclear Information System (INIS)

Goudarzi, Reza; Johannesson, Lars-Erik

2009-07-01

The Prototype Repository Test consists of two sections. The installation of the first Section of Prototype Repository was made during summer and autumn 2001 and Section 2 was installed in spring and summer 2003. This report presents data from measurements in the Prototype Repository during the period 010917-090601. The report is organized so that the actual measured results are shown in Appendix 1-10, where Appendix 8 deals with measurements of canister displacements (by AITEMIN), Appendix 9 deals with geo-electric measurements in the backfill (by GRS), Appendix 10 deals with stress and strain measurement in the rock (by BBK) and Appendix 11 deals with measurement of water pressure in the rock (by VBB/VIAK). The main report and Appendix 1-7 deal with the rest of the measurements

Aespoe Hard Rock Laboratory. Prototype Repository. Sensors data report (Period 010917-081201) Report No: 20

International Nuclear Information System (INIS)

Goudarzi, Reza; Johannesson, Lars-Erik

2009-03-01

The Prototype Repository Test consists of two sections. The installation of the first Section of Prototype Repository was made during summer and autumn 2001 and Section 2 was installed in spring and summer 2003. This report presents data from measurements in the Prototype Repository during the period 010917-081201. The report is organized so that the actual measured results are shown in Appendix 1-10, where Appendix 8 deals with measurements of canister displacements (by AITEMIN), Appendix 9 deals with geo-electric measurements in the backfill (by GRS), Appendix 10 deals with stress and strain measurement in the rock (by BBK) and Appendix 11 deals with measurement of water pressure in the rock (by VBB/VIAK). The main report and Appendix 1-7 deal with the rest of the measurements

Aespoe Hard Rock Laboratory. Prototype Repository. Sensors data report (Period 010917-090601) Report No: 21

Energy Technology Data Exchange (ETDEWEB)

Goudarzi, Reza; Johannesson, Lars-Erik (Clay Technology AB, Lund (Sweden))

2009-07-15

The Prototype Repository Test consists of two sections. The installation of the first Section of Prototype Repository was made during summer and autumn 2001 and Section 2 was installed in spring and summer 2003. This report presents data from measurements in the Prototype Repository during the period 010917-090601. The report is organized so that the actual measured results are shown in Appendix 1-10, where Appendix 8 deals with measurements of canister displacements (by AITEMIN), Appendix 9 deals with geo-electric measurements in the backfill (by GRS), Appendix 10 deals with stress and strain measurement in the rock (by BBK) and Appendix 11 deals with measurement of water pressure in the rock (by VBB/VIAK). The main report and Appendix 1-7 deal with the rest of the measurements.

Aespoe Hard Rock Laboratory. Prototype Repository. Sensors data report (Period 010917-081201) Report No: 20

Energy Technology Data Exchange (ETDEWEB)

Goudarzi, Reza; Johannesson, Lars-Erik (Clay Technology AB, Lund (Sweden))

2009-03-15

The Prototype Repository Test consists of two sections. The installation of the first Section of Prototype Repository was made during summer and autumn 2001 and Section 2 was installed in spring and summer 2003. This report presents data from measurements in the Prototype Repository during the period 010917-081201. The report is organized so that the actual measured results are shown in Appendix 1-10, where Appendix 8 deals with measurements of canister displacements (by AITEMIN), Appendix 9 deals with geo-electric measurements in the backfill (by GRS), Appendix 10 deals with stress and strain measurement in the rock (by BBK) and Appendix 11 deals with measurement of water pressure in the rock (by VBB/VIAK). The main report and Appendix 1-7 deal with the rest of the measurements.

Aespoe Hard Rock Laboratory. Prototype Repository. Sensors data report (Period 010917-091201) Report No: 22

Energy Technology Data Exchange (ETDEWEB)

Goudarzi, Reza; Johannesson, Lars-Erik (Clay Technology AB, Lund (Sweden))

2009-12-15

The Prototype Repository Test consists of two sections. The installation of the first Section of Prototype Repository was made during summer and autumn 2001 and Section 2 was installed in spring and summer 2003. This report presents data from measurements in the Prototype Repository during the period 010917-091201. The report is organized so that the actual measured results are shown in Appendix 1-10, where Appendix 8 deals with measurements of canister displacements (by AITEMIN), Appendix 9 deals with geo-electric measurements in the backfill (by GRS), Appendix 10 deals with stress and strain measurement in the rock (by AaF) and Appendix 11 deals with measurement of water pressure in the rock (by VBB/VIAK). The main report and Appendix 1-7 deal with the rest of the measurements.

Using hardness to model yield and tensile strength

Energy Technology Data Exchange (ETDEWEB)

Hawk, Jeffrey A.; Dogan, Omer N.; Schrems, Karol K.

2005-02-01

The current direction in hardness research is towards smaller and smaller loads as nano-scale materials are developed. There remains, however, a need to investigate the mechanical behavior of complex alloys for severe environment service. In many instances this entails casting large ingots and making numerous tensile samples as the bounds of the operating environment are explored. It is possible to gain an understanding of the tensile strength of these alloys using room and elevated temperature hardness in conjunction with selected tensile tests. The approach outlined here has its roots in the work done by Tabor for metals and low alloy and carbon steels. This research seeks to extend the work to elevated temperatures for multi-phase, complex alloys. A review of the approach will be given after which the experimental data will be examined. In particular, the yield stress and tensile strength will be compared to their corresponding hardness based values.

Strategy for a Rock Mechanics Site Descriptive Model. Development and testing of the theoretical approach

Energy Technology Data Exchange (ETDEWEB)

Staub, Isabelle; Fredriksson, Anders; Outters, Nils [Golder Associates AB, Uppsala (Sweden)

2002-05-01

In the purpose of studying the possibilities of a Deep Repository for spent fuel, the Swedish Nuclear and Fuel Management Company (SKB) is currently planning for Site Investigations. Data collected from these Site Investigations are interpreted and analysed to achieve the full Site Description, which is built up of models from all the disciplines that are considered of importance for the Site Description. One of these models is the Rock Mechanical Descriptive Model,which would be developed for any site in hard crystalline rock, and is a combination and evaluation of the characterisation of rock mass by means of empirical relationships and a theoretical approach based on numerical modelling. The present report describes the theoretical approach. The characterisation of the mechanical properties of the rock mass, viewed as a unit consisting of intact rock and fractures, is achieved by numerical simulations with following input parameters: initial stresses, fracture geometry, distribution of rock mechanical properties, such as deformation and strength parameters, for the intact rock and for the fractures. The numerical modelling was performed with the two-dimensional code UDEC, and the rock block models were generated from 2D trace sections extracted from the 3D Discrete Fracture Network (DFN) model. Assumptions and uncertainties related to the set-up of the model are considered. The numerical model was set-up to simulate a plain strain-loading test. Different boundary conditions were applied on the model for simulating stress conditions (I) in the undisturbed rock mass, and (II) at the proximity of a tunnel. In order to assess the reliability of the model sensitivity analyses have been conducted on some rock block models for defining the dependency of mechanical properties to in situ stresses, the influence of boundary conditions, rock material and joint constitutive models used to simulate the behaviour of intact rock and fractures, domain size and anisotropy. To

Strategy for a Rock Mechanics Site Descriptive Model. Development and testing of the theoretical approach

International Nuclear Information System (INIS)

Staub, Isabelle; Fredriksson, Anders; Outters, Nils

2002-05-01

In the purpose of studying the possibilities of a Deep Repository for spent fuel, the Swedish Nuclear and Fuel Management Company (SKB) is currently planning for Site Investigations. Data collected from these Site Investigations are interpreted and analysed to achieve the full Site Description, which is built up of models from all the disciplines that are considered of importance for the Site Description. One of these models is the Rock Mechanical Descriptive Model,which would be developed for any site in hard crystalline rock, and is a combination and evaluation of the characterisation of rock mass by means of empirical relationships and a theoretical approach based on numerical modelling. The present report describes the theoretical approach. The characterisation of the mechanical properties of the rock mass, viewed as a unit consisting of intact rock and fractures, is achieved by numerical simulations with following input parameters: initial stresses, fracture geometry, distribution of rock mechanical properties, such as deformation and strength parameters, for the intact rock and for the fractures. The numerical modelling was performed with the two-dimensional code UDEC, and the rock block models were generated from 2D trace sections extracted from the 3D Discrete Fracture Network (DFN) model. Assumptions and uncertainties related to the set-up of the model are considered. The numerical model was set-up to simulate a plain strain-loading test. Different boundary conditions were applied on the model for simulating stress conditions (I) in the undisturbed rock mass, and (II) at the proximity of a tunnel. In order to assess the reliability of the model sensitivity analyses have been conducted on some rock block models for defining the dependency of mechanical properties to in situ stresses, the influence of boundary conditions, rock material and joint constitutive models used to simulate the behaviour of intact rock and fractures, domain size and anisotropy. To

Uniaxial experimental study of the acoustic emission and deformation behavior of composite rock based on 3D digital image correlation (DIC)

Science.gov (United States)

Cheng, Jian-Long; Yang, Sheng-Qi; Chen, Kui; Ma, Dan; Li, Feng-Yuan; Wang, Li-Ming

2017-12-01

In this paper, uniaxial compression tests were carried out on a series of composite rock specimens with different dip angles, which were made from two types of rock-like material with different strength. The acoustic emission technique was used to monitor the acoustic signal characteristics of composite rock specimens during the entire loading process. At the same time, an optical non-contact 3D digital image correlation technique was used to study the evolution of axial strain field and the maximal strain field before and after the peak strength at different stress levels during the loading process. The effect of bedding plane inclination on the deformation and strength during uniaxial loading was analyzed. The methods of solving the elastic constants of hard and weak rock were described. The damage evolution process, deformation and failure mechanism, and failure mode during uniaxial loading were fully determined. The experimental results show that the θ = 0{°}-45{°} specimens had obvious plastic deformation during loading, and the brittleness of the θ = 60{°}-90{°} specimens gradually increased during the loading process. When the anisotropic angle θ increased from 0{°} to 90{°}, the peak strength, peak strain, and apparent elastic modulus all decreased initially and then increased. The failure mode of the composite rock specimen during uniaxial loading can be divided into three categories: tensile fracture across the discontinuities (θ = 0{°}-30{°}), sliding failure along the discontinuities (θ = 45{°}-75{°}), and tensile-split along the discontinuities (θ = 90{°}). The axial strain of the weak and hard rock layers in the composite rock specimen during the loading process was significantly different from that of the θ = 0{°}-45{°} specimens and was almost the same as that of the θ = 60{°}-90{°} specimens. As for the strain localization highlighted in the maximum principal strain field, the θ = 0{°}-30{°} specimens appeared in the rock

Assessment of radiological significance of naturally occurring radionuclides in soil and rock matrices around Kakrapar environment

International Nuclear Information System (INIS)

Patra, A.K.; Jaison, T.J.; Baburajan, A.; Hegde, A.G.

2008-01-01

The activity and gamma-absorbed dose rate due to the naturally occurring radionuclides in the terrestrial environment such as 238 U, 232 Th and 40 K were determined in soil and rock samples collected around Kakrapar Atomic Power Plant site, using gamma-ray spectrometry. The mean concentration levels measured in Kakrapar soil from naturally occurring radioisotopes such as 238 U, 232 Th and 40 K are lower than the corresponding global average values obtained in worldwide soil. The external hazard index (Hex) and absorbed gamma dose rate in air outdoors is observed to be 0.04-0.18 and 3.1-14.1 nGy h -1 , respectively. (authors)

Mechanical weathering and rock erosion by climate-dependent subcritical cracking

Science.gov (United States)

Eppes, Martha-Cary; Keanini, Russell

2017-06-01

This work constructs a fracture mechanics framework for conceptualizing mechanical rock breakdown and consequent regolith production and erosion on the surface of Earth and other terrestrial bodies. Here our analysis of fracture mechanics literature explicitly establishes for the first time that all mechanical weathering in most rock types likely progresses by climate-dependent subcritical cracking under virtually all Earth surface and near-surface environmental conditions. We substantiate and quantify this finding through development of physically based subcritical cracking and rock erosion models founded in well-vetted fracture mechanics and mechanical weathering, theory, and observation. The models show that subcritical cracking can culminate in significant rock fracture and erosion under commonly experienced environmental stress magnitudes that are significantly lower than rock critical strength. Our calculations also indicate that climate strongly influences subcritical cracking—and thus rock weathering rates—irrespective of the source of the stress (e.g., freezing, thermal cycling, and unloading). The climate dependence of subcritical cracking rates is due to the chemophysical processes acting to break bonds at crack tips experiencing these low stresses. We find that for any stress or combination of stresses lower than a rock's critical strength, linear increases in humidity lead to exponential acceleration of subcritical cracking and associated rock erosion. Our modeling also shows that these rates are sensitive to numerous other environment, rock, and mineral properties that are currently not well characterized. We propose that confining pressure from overlying soil or rock may serve to suppress subcritical cracking in near-surface environments. These results are applicable to all weathering processes.

Rock index properties for geoengineering in the Paradox Basin

International Nuclear Information System (INIS)

O'Rourke, J.E.; Rey, P.H.; Alviti, E.; Capps, C.C.

1986-02-01

Previous researchers have investigated the use of a number of rapid index tests that can be used on core samples, or in situ, to determine rock properties needed for geoengineering design, or to predict construction performance in these rock types. Selected research is reviewed, and the correlations of index tests with laboratory tests of rock properties found by the earlier investigators are discussed. The selection and testing of rock core samples from the Gibson Dome No. 1 borehole in Paradox Basin are described. The samples consist primarily of non-salt rock above salt cycle 6, but include some samples of anhydrite and salt cycle 6. The index tests included the point load test, Schmidt hammer rebound test, and abrasion hardness test. Statistical methods were used to analyze the correlations of index test data with laboratory test data of rock properties for the same core. Complete statistical results and computer-generated graphics are presented; these results are discussed in relation to the work of earlier investigations for index testing of similar rock types. Generally, fair to good correlations were obtained for predicting unconfined compressive strength and Young's modulus for sandstone and siltstone, while poorer correlations were found for limestone. This may be due to the large variability of limestone properties compared to the small number of samples. Overall, the use of index tests to assess rock properties at Paradox Basin appears to be practial for some conceptual and preliminary design needs, and the technique should prove useful at any salt repository site. However, it is likely that specific correlations should be demonstrated separately for each site, and the data base for establishing the correlations should probably include at least several hundred data points for each type

Pore Type Classification on Carbonate Reservoir in Offshore Sarawak using Rock Physics Model and Rock Digital Images

International Nuclear Information System (INIS)

Lubis, L A; Harith, Z Z T

2014-01-01

It has been recognized that carbonate reservoirs are one of the biggest sources of hydrocarbon. Clearly, the evaluation of these reservoirs is important and critical. For rigorous reservoir characterization and performance prediction from geophysical measurements, the exact interpretation of geophysical response of different carbonate pore types is crucial. Yet, the characterization of carbonate reservoir rocks is difficult due to their complex pore systems. The significant diagenesis process and complex depositional environment makes pore systems in carbonates far more complicated than in clastics. Therefore, it is difficult to establish rock physics model for carbonate rock type. In this paper, we evaluate the possible rock physics model of 20 core plugs of a Miocene carbonate platform in Central Luconia, Sarawak. The published laboratory data of this area were used as an input to create the carbonate rock physics models. The elastic properties were analyzed to examine the validity of an existing analytical carbonate rock physics model. We integrate the Xu-Payne Differential Effective Medium (DEM) Model and the elastic modulus which was simulated from a digital carbonate rock image using Finite Element Modeling. The results of this integration matched well for the separation of carbonate pore types and sonic P-wave velocity obtained from laboratory measurement. Thus, the results of this study show that the integration of rock digital image and theoretical rock physics might improve the elastic properties prediction and useful for more advance geophysical techniques (e.g. Seismic Inversion) of carbonate reservoir in Sarawak

Computer modeling of inelastic wave propagation in porous rock

International Nuclear Information System (INIS)

Cheney, J.A.; Schatz, J.F.; Snell, C.

1979-01-01

Computer modeling of wave propagation in porous rock has several important applications. Among them are prediction of fragmentation and permeability changes to be caused by chemical explosions used for in situ resource recovery, and the understanding of nuclear explosion effects such as seismic wave generation, containment, and site hardness. Of interest in all these applications are the distance from the source to which inelastic effects persist and the amount of porosity change within the inelastic region. In order to study phenomena related to these applications, the Cam Clay family of models developed at Cambridge University was used to develop a similar model that is applicable to wave propagation in porous rock. That model was incorporated into a finite-difference wave propagation computer code SOC. 10 figures, 1 table

Radionuclide Geomicrobiology of the Deep Biosphere

DEFF Research Database (Denmark)

Anderson, Craig; Johnsson, Anna; Moll, Henry

2011-01-01

aerobic bacterial metabolism, microbial proliferation, biofilm development, and iron oxide formation. In these environments, the stalk-forming bacterium Gallionella may act as a scaffold for iron oxide precipitation on biological material. In situ work in the Aspo Hard Rock Laboratory tunnel indicated......This review summarizes research into interactions between microorganisms and radionuclides under conditions typical of a repository for high-level radioactive waste in deep hard rock environments at a depth of approximately 500 m. The cell-radionuclide interactions of strains of two bacterial...

Influence of convective-energy transfer on calculated temperature distributions in proposed hard-rock nuclear waste repositories

Energy Technology Data Exchange (ETDEWEB)

Eaton, R R; Reda, D C [Sandia National Labs., Albuquerque, NM (USA)

1982-06-01

This study assesses the relative influence of convective-energy transfer on predicted temperature distributions for a nuclear-waste repository located in water-saturated rock. Using results for energy transfer by conduction only (no water motion) as a basis of comparison, it is shown that a considerable amount of energy can be removed from the repository by pumping out water that migrates into the drift from regions adjacent to the buried waste canisters. Furthermore, the results show that the influence of convective-energy transfer on mine drift cooling requirements can be significant for cases where the in-situ permeability of the rock is greater than one millidarcy (a regime potentially encountered in repository scenarios).

On the dual nature of lichen-induced rock surface weathering in contrasting micro-environments.

Science.gov (United States)

Marques, Joana; Gonçalves, João; Oliveira, Cláudia; Favero-Longo, Sergio E; Paz-Bermúdez, Graciela; Almeida, Rubim; Prieto, Beatriz

2016-10-01

Contradictory evidence from biogeomorphological studies has increased the debate on the extent of lichen contribution to differential rock surface weathering in both natural and cultural settings. This study, undertaken in Côa Valley Archaeological Park, aimed at evaluating the effect of rock surface orientation on the weathering ability of dominant lichens. Hyphal penetration and oxalate formation at the lichen-rock interface were evaluated as proxies of physical and chemical weathering, respectively. A new protocol of pixel-based supervised image classification for the analysis of periodic acid-Schiff stained cross-sections of colonized schist revealed that hyphal spread of individual species was not influenced by surface orientation. However, hyphal spread was significantly higher in species dominant on northwest facing surfaces. An apparently opposite effect was noticed in terms of calcium oxalate accumulation at the lichen-rock interface; it was detected by Raman spectroscopy and complementary X-ray microdiffraction on southeast facing surfaces only. These results suggest that lichen-induced physical weathering may be most severe on northwest facing surfaces by means of an indirect effect of surface orientation on species abundance, and thus dependent on the species, whereas lichen-induced chemical weathering is apparently higher on southeast facing surfaces and dependent on micro-environmental conditions, giving only weak support to the hypothesis that lichens are responsible for the currently observed pattern of rock-art distribution in Côa Valley. Assumptions about the drivers of open-air rock-art distribution patterns elsewhere should also consider the micro-environmental controls of lichen-induced weathering, to avoid biased measures of lichen contribution to rock-art deterioration. © 2016 by the Ecological Society of America.

The influence of microwave irradiation on rocks for microwave-assisted underground excavation

Directory of Open Access Journals (Sweden)

Ferri Hassani

2016-02-01

Full Text Available Demand is growing for explosive-free rock breakage systems for civil and mining engineering, and space industry applications. This paper highlights the work being undertaken in the Geomechanics Laboratory of McGill University to make a real application of microwave-assisted mechanical rock breakage to full-face tunneling machines and drilling. Comprehensive laboratory tests investigated the effect of microwave radiation on temperature profiles and strength reduction in hard rocks (norite, granite, and basalt for a range of exposure times and microwave power levels. The heating rate on the surface of the rock specimens linearly decreased with distance between the sample and the microwave antenna, regardless of microwave power level and exposure time. Tensile and uniaxial compressive strengths were reduced with increasing exposure time and power level. Scanning electron micrographs (SEMs highlighted fracture development in treated basalt. It was concluded that the microwave power level has a strong positive influence on the amount of heat damage induced to the rock surface. Numerical simulations of electric field intensity and wave propagation conducted with COMSOL Multiphysics® software generated temperature profiles that were in close agreement with experimental results.

SITE 94. Modelling of groundwater chemistry at Aespoe Hard Rock Laboratory

Energy Technology Data Exchange (ETDEWEB)

Emren, A.T. [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Nuclear Chemistry

1999-02-01

In this report a model is described, which has been able to give agreement between observed and modelled values for more than ten element concentrations (including pH and pE values). The model makes use of a number of steady state waters which are mixed naturally after which the mixtures react with minerals in the fractures. The end member waters are supposed to have been present in the fracture system during a time interval which is long enough for the rock groundwater system to have reached a steady state. Some elements, e.g. chlorine, is modelled as conservative (inert with respect to the rock). Most element concentrations cannot be explained from mixing alone. Rather reactions with the fracture walls have to be taken into account. The situation is complicated by the fact that a system comprised of groundwater and a number of fracture minerals may violate Gibb`s phase rule. In such a system, no global equilibrium state exists, and thus the water can never reach equilibrium with respect to all the fracture minerals. The end member waters eventually formed can be expected to be in a steady state condition rather than equilibrium with respect to the fracture minerals. It should be noted that such a steady state is not an equilibrium state. Rather, the water chemistry has to fluctuate as a result of spatial variability in the local mineral set. In most cases when an end member water is sampled, a large number of local waters are mixed causing the fluctuations to cancel out. The CRACKER is a program which has been developed to handle this complicated chemical situation. It couples chemistry and transport, using elaborate chemical modelling in combination with a simplified transport model. The program simulates chemical reactions of groundwater flowing through a plane fracture. The simulation results show that although the end member waters are far from equilibrium with respect to most of the minerals, they are in a steady state with respect to the rock. The chemistry

SITE 94. Modelling of groundwater chemistry at Aespoe Hard Rock Laboratory

International Nuclear Information System (INIS)

Emren, A.T.

1999-02-01

In this report a model is described, which has been able to give agreement between observed and modelled values for more than ten element concentrations (including pH and pE values). The model makes use of a number of steady state waters which are mixed naturally after which the mixtures react with minerals in the fractures. The end member waters are supposed to have been present in the fracture system during a time interval which is long enough for the rock groundwater system to have reached a steady state. Some elements, e.g. chlorine, is modelled as conservative (inert with respect to the rock). Most element concentrations cannot be explained from mixing alone. Rather reactions with the fracture walls have to be taken into account. The situation is complicated by the fact that a system comprised of groundwater and a number of fracture minerals may violate Gibb's phase rule. In such a system, no global equilibrium state exists, and thus the water can never reach equilibrium with respect to all the fracture minerals. The end member waters eventually formed can be expected to be in a steady state condition rather than equilibrium with respect to the fracture minerals. It should be noted that such a steady state is not an equilibrium state. Rather, the water chemistry has to fluctuate as a result of spatial variability in the local mineral set. In most cases when an end member water is sampled, a large number of local waters are mixed causing the fluctuations to cancel out. The CRACKER is a program which has been developed to handle this complicated chemical situation. It couples chemistry and transport, using elaborate chemical modelling in combination with a simplified transport model. The program simulates chemical reactions of groundwater flowing through a plane fracture. The simulation results show that although the end member waters are far from equilibrium with respect to most of the minerals, they are in a steady state with respect to the rock. The chemistry

Underground large scale test facility for rocks

International Nuclear Information System (INIS)

Sundaram, P.N.

1981-01-01

This brief note discusses two advantages of locating the facility for testing rock specimens of large dimensions in an underground space. Such an environment can be made to contribute part of the enormous axial load and stiffness requirements needed to get complete stress-strain behavior. The high pressure vessel may also be located below the floor level since the lateral confinement afforded by the rock mass may help to reduce the thickness of the vessel

Boring and Sealing Rock with Directed Energy Millimeter-Waves

Science.gov (United States)

Woskov, P.; Einstein, H. H.; Oglesby, K.

2015-12-01

Millimeter-wave directed energy is being investigated to penetrate into deep crystalline basement rock formations to lower well costs and to melt rocks, metals, and other additives to seal wells for applications that include nuclear waste storage and geothermal energy. Laboratory tests have established that intense millimeter-wave (MMW) beams > 1 kW/cm2 can melt and/ or vaporize hard crystalline rocks. In principle this will make it possible to create open boreholes and a method to seal them with a glass/ceramic liner and plug formed from the original rock or with other materials. A 10 kW, 28 GHz commercial (CPI) gyrotron system with a launched beam diameter of about 32 mm was used to heat basalt, granite, limestone, and sandstone specimens to temperatures over 2500 °C to create melts and holes. A calibrated 137 GHz radiometer view, collinear with the heating beam, monitored real time peak rock temperature. A water load surrounding the rock test specimen primarily monitored unabsorbed power at 28 GHz. Power balance analysis of the laboratory observations shows that the temperature rise is limited by radiative heat loss, which would be expected to be trapped in a borehole. The analysis also indicates that the emissivity (absorption efficiency) in the radiated infrared range is lower than the emissivity at 28 GHz, giving the MMW frequency range an important advantage for rock melting. Strength tests on one granite type indicated that heating the rock initially weakens it, but with exposure to higher temperatures the resolidified black glassy product regains strength. Basalt was the easiest to melt and penetrate, if a melt leak path was provided, because of its low viscosity. Full beam holes up to about 50 mm diameter (diffraction increased beam size) were achieved through 30 mm thick basalt and granite specimens. Laboratory experiments to form a seal in an existing hole have also been carried out by melting rock and a simulated steel casing.

Total-dose hardness assurance for low earth orbit

International Nuclear Information System (INIS)

Maurer, R.H.; Suter, J.J.

1987-01-01

The Low Earth Orbit radiation environment has two significant characteristics that make laboratory simulation exposures difficult: (1) a low dose rate and (2) many cycles of low dose accumulation followed by dose-free annealing. Hardness assurance considerations for this environment are discussed and related to data from the testing of Advanced Low Power Schottky and High-speed CMOS devices

Dynamic Mechanical Behavior of Dry and Water Saturated Igneous Rock with Acoustic Emission Monitoring

Directory of Open Access Journals (Sweden)

Jun Guo

2018-01-01

Full Text Available The uniaxial cyclic loading tests have been conducted to study the mechanical behavior of dry and water saturated igneous rock with acoustic emission (AE monitoring. The igneous rock samples are dried, naturally immersed, and boiled to get specimens with different water contents for the testing. The mineral compositions and the microstructures of the dry and water saturated igneous rock are also presented. The dry specimens present higher strength, fewer strains, and rapid increase of AE count subjected to the cyclic loading, which reflects the hard and brittle behavior and strong burst proneness of igneous rock. The water saturated specimens have lower peak strength, more accumulated strains, and increase of AE count during the cyclic loading. The damage of the igneous rocks with different water contents has been identified by the Felicity Ratio Analysis. The cyclic loading and unloading increase the dislocation between the mineral aggregates and the water-rock interactions further break the adhesion of the clay minerals, which jointly promote the inner damage of the igneous rock. The results suggest that the groundwater can reduce the burst proneness of the igneous rock but increase the potential support failure of the surrounding rock in igneous invading area. In addition, the results inspire the fact that the water injection method is feasible for softening the igneous rock and for preventing the dynamic disasters within the roadways and working faces located in the igneous intrusion area.

Modeling of Principal Flank Wear: An Empirical Approach Combining the Effect of Tool, Environment and Workpiece Hardness

Science.gov (United States)

Mia, Mozammel; Al Bashir, Mahmood; Dhar, Nikhil Ranjan

2016-10-01

Hard turning is increasingly employed in machining, lately, to replace time-consuming conventional turning followed by grinding process. An excessive amount of tool wear in hard turning is one of the main hurdles to be overcome. Many researchers have developed tool wear model, but most of them developed it for a particular work-tool-environment combination. No aggregate model is developed that can be used to predict the amount of principal flank wear for specific machining time. An empirical model of principal flank wear (VB) has been developed for the different hardness of workpiece (HRC40, HRC48 and HRC56) while turning by coated carbide insert with different configurations (SNMM and SNMG) under both dry and high pressure coolant conditions. Unlike other developed model, this model includes the use of dummy variables along with the base empirical equation to entail the effect of any changes in the input conditions on the response. The base empirical equation for principal flank wear is formulated adopting the Exponential Associate Function using the experimental results. The coefficient of dummy variable reflects the shifting of the response from one set of machining condition to another set of machining condition which is determined by simple linear regression. The independent cutting parameters (speed, rate, depth of cut) are kept constant while formulating and analyzing this model. The developed model is validated with different sets of machining responses in turning hardened medium carbon steel by coated carbide inserts. For any particular set, the model can be used to predict the amount of principal flank wear for specific machining time. Since the predicted results exhibit good resemblance with experimental data and the average percentage error is <10 %, this model can be used to predict the principal flank wear for stated conditions.

Aespoe Hard Rock Laboratory. Analysis of fracture networks based on the integration of structural and hydrogeological observations on different scales

Energy Technology Data Exchange (ETDEWEB)

Bossart, P. [Geotechnical Inst. Ltd., Bern (Switzerland); Hermanson, Jan [Golder Associates, Stockholm (Sweden); Mazurek, M. [Univ. of Bern (Switzerland)

2001-05-01

Fracture networks at Aespoe have been studied for several rock types exhibiting different degrees of ductile and brittle deformation, as well as on different scales. Mesoscopic fault systems have been characterised and classified in an earlier report, this report focuses mainly on fracture networks derived on smaller scales, but also includes mesoscopic and larger scales. The TRUE-1 block has been selected for detailed structural analysis on a small scale due to the high density of relevant information. In addition to the data obtained from core materials, structural maps, BIP data and the results of hydro tests were synthesised to derive a conceptual structural model. The approach used to derive this conceptual model is based on the integration of deterministic structural evidence, probabilistic information and both upscaling and downscaling of observations and concepts derived on different scales. Twelve fracture networks mapped at different sites and scales and exhibiting various styles of tectonic deformation were analysed for fractal properties and structural and hydraulic interconnectedness. It was shown that these analysed fracture networks are not self-similar. An important result is the structural and hydraulic interconnectedness of fracture networks on all scales in the Aespoe rocks, which is further corroborated by geochemical evidence. Due to the structural and hydraulic interconnectedness of fracture systems on all scales at Aespoe, contaminants from waste canisters placed in tectonically low deformation environments would be transported - after having passed through the engineered barriers -from low-permeability fractures towards higher permeability fractures and may thus eventually reach high-permeability features.

Aespoe Hard Rock Laboratory. Analysis of fracture networks based on the integration of structural and hydrogeological observations on different scales

International Nuclear Information System (INIS)

Bossart, P.; Hermanson, Jan; Mazurek, M.

2001-05-01

Fracture networks at Aespoe have been studied for several rock types exhibiting different degrees of ductile and brittle deformation, as well as on different scales. Mesoscopic fault systems have been characterised and classified in an earlier report, this report focuses mainly on fracture networks derived on smaller scales, but also includes mesoscopic and larger scales. The TRUE-1 block has been selected for detailed structural analysis on a small scale due to the high density of relevant information. In addition to the data obtained from core materials, structural maps, BIP data and the results of hydro tests were synthesised to derive a conceptual structural model. The approach used to derive this conceptual model is based on the integration of deterministic structural evidence, probabilistic information and both upscaling and downscaling of observations and concepts derived on different scales. Twelve fracture networks mapped at different sites and scales and exhibiting various styles of tectonic deformation were analysed for fractal properties and structural and hydraulic interconnectedness. It was shown that these analysed fracture networks are not self-similar. An important result is the structural and hydraulic interconnectedness of fracture networks on all scales in the Aespoe rocks, which is further corroborated by geochemical evidence. Due to the structural and hydraulic interconnectedness of fracture systems on all scales at Aespoe, contaminants from waste canisters placed in tectonically low deformation environments would be transported - after having passed through the engineered barriers -from low-permeability fractures towards higher permeability fractures and may thus eventually reach high-permeability features

Aespoe Hard Rock Laboratory. Backfill and Plug test. Hydraulic testing of core drilled boreholes in the ZEDEX drift

Energy Technology Data Exchange (ETDEWEB)

Ludvigson, Jan-Erik; Nordqvist, Rune; Ekman, Lennart; Hansson, Kent (GEOSIGMA AB, Uppsala (Sweden))

2009-07-01

The present report documents the performance and results of hydraulic testing in selected core boreholes in the Zedex drift. The holes will be used as rock instrumentation boreholes during the Backfill and Plug Test at Aespoe HRL. The testing involves both 1 m long boreholes with 56 mm diameter as well as longer boreholes c. 5 m, 8 m and 25 m long with 56 mm or 76 mm diameter. Only single-hole tests were performed. The tests were carried out as short-time constant head injection tests since all boreholes tested (except one) were non-flowing before tests. The injection phase was followed by a pressure recovery phase. Furthermore, the tests were carried out as single-packer tests. A specially designed test system was used for the tests. The main evaluation of the tests was performed on data from the recovery phase by a new approach based on a non-linear regression technique combined with a flow simulation model (SUTRA). The tests in the 1 m-holes (testing the interval c. 0.3-0.7 m in the rock perpendicular to the tunnel face) show that the hydraulic conductivity of the superficial rock around the Zedex drift in general is low. However, during testing in some boreholes, visible leakage in the rock occurred through superficial fractures into the tunnel. These fractures were mainly located in the floor of the Zedex drift and are probably blast-induced. These fractures have a high hydraulic conductivity. The tests in the longer boreholes show that the hydraulic conductivity further into the rock in general is below c. 1x10-10 m/s. Increased hydraulic conductivity (c.1.5x10-8 m/s) was only observed in the flowing borehole KXZSD8HL.

Characteristics and genesis of porphyroclastic lava rock in Xiangshan

International Nuclear Information System (INIS)

Zhou Xiaohua; Wang Zhuning

2012-01-01

Due to the transitional characteristics of porphyroclastic lava rock in Xiangshan of Jiangxi province, there are a variety of views on its genesis, petrographic attribution. This is because the marginal facies of the porphyroclastic lava is with ignimbrite and tuff characteristics, its transition phase has the characteristics of lava, and its intermediate phase has the feature of sub-volcanic rocks, further more, different texture of the rocks bears transition relationship. By the study of mineral composition, REE pattern, trace elements, isotopes, we put forward that the porphyroclastic lava is formed by the remelting of basement metamorphic rocks. The rocks was believed to be formed in the environment similar to volcanics and subvolcanics, and quite different to plutonic rocks due to the features of low-structure of potassium feldspar phenocrysts and solution mechanism, because the porphyroclastic lava phenocrysts occurs as fragments and maybe related to cryptoexplosion. Therefore the rocks was believed to belong to the volcano extrusive facies. (authors)

Geochemical modelling of grout-groundwater-rock interactions at the seal-rock interface

International Nuclear Information System (INIS)

Alcorn, S.; Christian-Frear, T.

1992-02-01

Theoretical investigations into the longevity of repository seals have dealt primarily with the development of a methodology to evaluate interactions between portland cement-based grout and groundwater. Evaluation of chemical thermodynamic equilibria among grout, groundwater, and granitic host rock phases using the geochemical codes EQ3NR/EQ6 suggests that a fracture filled with grout and saturated with groundwater will tend to fill and 'tighten' with time. These calculations predict that some grout and rock phases will dissolve, and that there will be precipitation of secondary phases which collectively have a larger overall volume than that of the material dissolved. Model assumptions include sealing of the fracture in a sluggish hydrologic regime (low gradient) characterized by a saline groundwater environment. The results of the calculations suggest that buffering of the fracture seals chemical system by the granitic rock may be important in determining the long-term fate of grout seals and the resulting phase assemblage in the fracture. The similarity of the predicted reaction product phases to those observed in naturally filled fractures suggests that with time equilibrium will be approached and grouted fractures subject to low hydrologic gradients will continue to seal. If grout injected into fractures materially reduces groundwater flux, the approach to chemical equilibrium will likely be accelerated. In light of this, even very thin or imperfectly grouted fractures would tighten in suitable hydrogeologic environments. In order to determine the period of time necessary to approach equilibrium, data on reaction rates are required. (au)

Genesis of Soils Formed from Mafic Igneous Rock in the Atlantic Forest Environment

Directory of Open Access Journals (Sweden)

Adailde do Carmo Santos

2016-01-01

Full Text Available ABSTRACT Different parent materials participate in the formation of soils in the hilly landscape of “Mar de Morros” in the Atlantic Forest environment. Those derived from mafic igneous rock (gabbro frequently show erosion problems because of land use, which is aggravated by the mountainous relief and soil attributes. This study evaluated the main pedogenic processes of soils formed from mafic igneous rock (gabbro in a toposequence in Pinheiral (RJ by characterizing physical, chemical, mineralogical and micromorphological attributes. The profiles are located at different sections in the toposequence: summit (P1, shoulder (P2, backslope (P3 and footslope (P4.They were classified according to the Brazilian System of Soil Classification (SiBCS and correlated to Soil Taxonomy. The soil morphology of profiles P2, P3 and P4 is expressed by a brownish-red color, blocky structure with high to moderate development, clay films and clay loam to clay texture, with a textural B horizon. P1 shows less development, with a shallow profile and the sequence of horizons A-C-Cr. The soils have a slightly low degree of weathering, identified by the presence of pyroxenes and feldspars in the sand fraction and montorillonite in the clay fraction; the sum of bases is from 15 to 24 cmolc kg-1; and cation exchange capacity (CEC is from 12 to 22 cmolc kg-1. A significant presence of clay skins was observed in the field and was confirmed by thin section analysis, which showed features such as argillans, ferriargillans and iron nodules. The soil profile at the summit (P1 was classified as Neossolo Regolítico Órtico (Typic Udorthents, and the other profiles as Chernossolo Argilúvicos Órticos (Typic Argiudolls.

In-situ rock melting applied to lunar base construction and for exploration drilling and coring on the moon

International Nuclear Information System (INIS)

Rowley, J.C.; Neudecker, J.W.

1984-01-01

An excavation technology based upon melting of rock and soil has been extensively developed at the prototype hardware and conceptual design levels for terrestrial conditions. Laboratory and field tests of rock-melting penetration have conclusively indicated that this excavation method is insensitive to rock, soil types, and conditions. Especially significant is the ability to form in-place glass linings or casings on the walls of boreholes, tunnels, and shafts. These factors indicate the unique potential for in situ construction of primary lunar base facilities. Drilling and coring equipment for resource exploration on the moon can also be devised that are largely automated and remotely operated. It is also very likely that lunar melt-glasses will have changed mechanical properties when formed in anhydrous and hard vacuum conditions. Rock melting experiments and prototype hardware designs for lunar rock-melting excavation applications are suggested

The role of major forest fires on rock physical decay in a Mediterranean environment

Science.gov (United States)

Shtober-Zisu, Nurit; Tessler, Naama; Tsatskin, Alexander; Greenbaum, Noam

2017-04-01

Massive destruction of carbonate rocks occurred on the slopes of Mt. Carmel (Israel), during a severe forest fire in 2010. The bedrock surfaces exhibited extensive exfoliation into flakes and spalls covering up to 80%-100% of the exposed rocks; detached boulders were totally fractured or disintegrated. The fire affected six carbonate units—various types of chalk, limestone, and dolomite. The burned flakes show a consistent tendency towards flatness, in all lithologies, as 85%-95% of the flakes were detached in the form of blades, plates, and slabs. The extent of the physical disruption depends on rock composition: the most severe response was found in the chalk formations which are covered by calcrete (Nari crusts). These rocks reacted by extreme exfoliation, at an average depth of 7.7 to 9.6 cm and a maximum depth of 20 cm. Scorched and blackened faces under the upper layer of spalls provide strong evidence that chalk breakdown took place at an early stage of the fire. The extreme response of the chalks can be explained by the laminar structure of the Nari, which served as planes of weakness for the rock destruction. Three years after the fire, the rocks continue to exfoliate and break down internally. As the harder surface of the Nari was removed, the more brittle underlying chalk is exposed to erosion. These flakes seem to play an important role in reforming the soil after the fire, especially by increasing the coarse particles percentage. These, in spite of the absence of vegetation cover, improve soil infiltration and percolation rates and cause long-term changes to the hydrological regime. It is difficult to estimate the frequency of high-intensity fires in the Carmel region over the past 2-3 million years, as well as the extension and density of the vegetation. It is even harder to assess the frequency of fires (and the destruction) of a single rock outcrop. Our findings show that rock outcrop may lose even 20 cm of its thickness in a single fire. This

Laboratory testing of a long expansion rock bolt support for energy-absorbing applications

Directory of Open Access Journals (Sweden)

Skrzypkowski Krzysztof

2018-01-01

Full Text Available The main purpose of rock support and reinforcement in underground mining is to maintain excavations safe and open for their intended lifespan. The basic type of rock mass reinforcement method both in ore and hard coal mining is rock bolt support. Very often, existing bolt support systems are not always capable of providing a reliable controlled performance. Therefore, in recent years energy-absorbing bolts which are exposed to dynamic loading, for example from rock burst caused by high rock stresses, earthquakes, or blasting have appeared. In this article particular attention was paid to short and long expansion bolts. Quasi-static tests of expansion bolts were carried out at the laboratory test facility in simulated mining conditions, especially for the KGHM Polska Miedź S.A. mines. In the underground mines of the Legnica-Głogów Copper District (LGOM the main way to protect the room excavation is rock bolt support with a length from 1.2 m to 2.6 m. Rock bolt support longer than 2.6 m is considered as additional support of excavations and is increasingly being used to reinforce the roofs. The comparisons of energy-absorbing short and long expansion bolts with a length of 1.8m, 3.6m and 5.2m were presented. In addition, for elastic and plastic range of each bolts were determined.

Laboratory testing of a long expansion rock bolt support for energy-absorbing applications

Science.gov (United States)

Skrzypkowski, Krzysztof

2018-01-01

The main purpose of rock support and reinforcement in underground mining is to maintain excavations safe and open for their intended lifespan. The basic type of rock mass reinforcement method both in ore and hard coal mining is rock bolt support. Very often, existing bolt support systems are not always capable of providing a reliable controlled performance. Therefore, in recent years energy-absorbing bolts which are exposed to dynamic loading, for example from rock burst caused by high rock stresses, earthquakes, or blasting have appeared. In this article particular attention was paid to short and long expansion bolts. Quasi-static tests of expansion bolts were carried out at the laboratory test facility in simulated mining conditions, especially for the KGHM Polska Miedź S.A. mines. In the underground mines of the Legnica-Głogów Copper District (LGOM) the main way to protect the room excavation is rock bolt support with a length from 1.2 m to 2.6 m. Rock bolt support longer than 2.6 m is considered as additional support of excavations and is increasingly being used to reinforce the roofs. The comparisons of energy-absorbing short and long expansion bolts with a length of 1.8m, 3.6m and 5.2m were presented. In addition, for elastic and plastic range of each bolts were determined.

Geological disposal of high-level radioactive waste and the role of rock engineering

International Nuclear Information System (INIS)

Sugihara, Kozo

2008-01-01

Japan Atomic Energy Agency (JAEA) and its predecessors have been conducting an extensive geoscientific research program since the 1970's in order to contribute to the formation of a firm scientific and technological basis for the geological disposal of high level radioactive waste in Japan. As a part of this program, in situ experiments have been performed at the Tono Mine in soft sedimentary rocks and at the Kamaishi Mine in hard crystalline rocks. An experiment on excavation disturbance has been one of these experiments and has revealed the extent and properties of the excavation disturbed zone (EDZ) and the applicability of available measurement methods. It is suggested that mechanical excavation and controlled excavation have reduced excavation damage of the rock mass around a drift, although some improvements in the currently available methods for measuring and simulating the EDZ are essential to understand excavation disturbance in more detail. JAEA is now promoting two underground research laboratory projects in Japan; the Mizunami Underground Research Laboratory (MIU) project for crystalline rocks and the Horonobe Underground Research Laboratory (Horonobe URL) project for sedimentary rocks. From a rock mechanical point of view, the major interest in these projects will be paid to failure phenomenon deep underground, rock stress estimation at larger scales and long-term physical stability of underground structure. These projects are open for international collaboration. (author)

Development of soda-lime glasses from ornamental rock wastes

International Nuclear Information System (INIS)

Babisk, Michelle Pereira

2009-01-01

During the ornamental rocks production, among other steps, one saw the rock blocks in order to transform them into semi-finished plates. In this step, expressive amounts of residues are generated, which are not properly discharged in nature, without any programmed utilization. The residues of silicide rocks present, in their compositions, oxides which are raw materials employed to fabricate soda-lime type glasses (containing SiO_2, Al_2O_3, CaO, Na_2O and K_2O). On the other hand the residues of carbonatic rocks are constituted of glass net modifier oxides, like CaO and MgO. In this work it was developed four types of soda-lime glasses using ornamental rock residues, where the glasses compositions were adjusted by adding sand, as silica source, as well as sodium and calcium carbonates as sources of Na_2O and CaO, respectively. The obtained glasses were characterized by means of Archimed's method for densities measurements, microstructure by using optical and electronic microscopy, phases by means of X-ray diffraction (XRD), hardness by Vickers indentation, spectroscopy (UV/VIS), and hydrolytic resistance according to ISO 719. The XRD analyses confirmed the compositions total vitrification, where the greened aspect of the samples was due to the presence of the iron oxides. The produced glasses properties were compared with those of commercial glasses aiming their industrial employment. The main difference between the produced glasses and those commercials varied primarily regarding the amount of carbonates incorporated. The results showed that the ornamental rocks residues may be used as raw materials for glasses fabrication, and they found a useful economic destination rather than discharge which promotes undesirable environmental impact. (author)

Radioactive waste repositories in hard rock aquifers--hydrodynamic aspects

International Nuclear Information System (INIS)

Thunvik, R.; Braester, C.

1984-01-01

A mathematical model for mass and heat flow and a computer program have been developed to demonstrate the effect of heat released from a hypothetical radioactive waste repository on the groundwater flow regime. The model, based on the continuum approach, conceptualizes the fracture pattern and the solid blocks as two overlapping continua and consists of a set of coupled nonlinear partial differential equations. The general form of the model is three-dimensional and can treat the fluid and rock either as two separate media with a quasi-steady exchange of heat between them or as a single equivalent medium with instantaneous thermal equilibrium. Numerical solutions have been obtained by the Galerkin finite element method. Examples have been presented for topographically different locations of the repository: below a horizontal ground surface, below a hill crest, below a hillside, and close to major fractures. The effects of constant permeability and porosity or downward decreasing with depth as well as the effect of anisotropic permeability have been investigated. Solutions include the velocity field, path lines, and traveling times of water particles passing the repository and the temperature distribution. The examples have been worked out for a two-dimensional flow domain, assuming that instantaneous thermal equilibrium takes place. This assumption was found to be justified by the relatively low flow velocities that occurred in the examples. Except for the location close to a major draining fracture, heat released from the radioactive waste repository may have a significant influence on the flow regime around the repository

Application of air hammer drilling technology in igneous rocks of Junggar basin

Science.gov (United States)

Zhao, Hongshan; Feng, Guangtong; Yu, Haiye

2018-03-01

There were many technical problems such as serious well deviation, low penetration rate and long drilling cycle in igneous rocks because of its hardness, strong abrasive and poor drillability, which severely influenced the exploration and development process of Junggar basin. Through analyzing the difficulties of gas drilling with roller bits in Well HS 2, conducting the mechanics experiments about igneous rock, and deeply describing the rock-breaking mechanism of air hammer drilling and its adaptability in igneous rocks, air hammer drilling can realize deviation control and fast drilling in igneous rocks of piedmont zone and avoid the wear and fatigue fracture of drilling strings due to its characteristics of low WOB, low RPM and high frequency impact. Through firstly used in igneous rocks of Well HS 201, compared with gas drilling with cone bit, the average penetration rate and one-trip footage of air hammer drilling respectively increased by more than 2.45 times and 6.42 times while the well deviation was always controlled less than 2 degrees. Two records for Block HS were set up such as the fastest penetration rate of 14.29m/h in Φ444.5mm well hole and the highest one-trip footage of 470.62m in Φ311.2mm well hole. So air hammer drilling was an effective way to realize optimal and fast drilling in the igneous rock formation of Junggar basin.

How did the ball of rock we live on get so nice?

Science.gov (United States)

Armstrong, K.

2017-12-01

We want to understand how the big ball of rock, water, and air we live on got to be as nice as it is. Some of the things that made our world so nice are what it's made of, and what happened to those things after they were all put together. When our home ball of rock was little, it got bigger by grabbing some of the other stuff that was close by in space. So our world is made of all that space stuff, which was rocks, and that stuff that turns red if you let it get wet. Most of that red stuff is deep down in the middle of the world, covered up by a lot of rocks. But there is a lot of it inside the rocks, too. That red stuff does a lot of cool stuff when it touches other things, especially the kind of air we like to breathe- that is what makes it turn red. Just one very tiny piece of the red stuff can join up with the breathing air in different ways: it can team up with none at all, or a little bit, or a lot, or even more. If we look at how much of the breathing air is teamed up with the red stuff inside the rocks, we can learn about how the rocks got there and what happened to them a long time ago. In the rocks that we can look at, there is more of the breathing air teamed up with the red stuff than we might have thought. We think that maybe that is because when more and more stuff tries to fit in the same small space, and gets pressed down, like it does deep down in our world, it can change in ways we do not expect. When our world was almost as big as it is now, it probably grabbed some space stuff that was almost as big as it was. The space stuff would have run into our world really hard, and that would have made everything really hot, hot enough to make all the rocks in the world move like water. We have an idea that maybe, when all the rocks on the world were really hot and moved around like water, deep down the red stuff and the breathing air might have got all pressed together very hard, so that more of the breathing air would team up with the red stuff than it

Cobalt allergy in hard metal workers

Energy Technology Data Exchange (ETDEWEB)

Fischer, T; Rystedt, I

1983-03-01

Hard metal contains about 10% cobalt. 853 hard metal workers were examined and patch tested with substances from their environment. Initial patch tests with 1% cobalt chloride showed 62 positive reactions. By means of secondary serial dilution tests, allergic reactions to cobalt were reproduced in 9 men and 30 women. Weak reactions could not normally be reproduced. A history of hand eczema was found in 36 of the 39 individuals with reproducible positive test reactions to cobalt, while 21 of 23 with a positive initial patch test but negative serial dilution test had never had any skin problems. Hand etching and hand grinding, mainly female activities and traumatic to the hands, were found to involve the greatest risk of cobalt sensitization. 24 individuals had an isolated cobalt allergy. They had probably been sensitized by hard metal work, while the individuals, all women, who had simultaneous nickel allergy had probably been sensitized to nickel before their employment and then became sensitized to cobalt by hard metal work. A traumatic occupation, which causes irritant contact dermatitis and/or a previous contact allergy or atopy is probably a prerequisite for the development of cobalt allergy.

Do Bare Rocks Exist on the Moon?

Science.gov (United States)

Allen, Carlton; Bandfield, Joshua; Greenhagen, Benjamin; Hayne, Paul; Leader, Frank; Paige, David

2017-01-01

Astronaut surface observations and close-up images at the Apollo and Chang'e 1 landing sites confirm that at least some lunar rocks have no discernable dust cover. However, ALSEP (Apollo Lunar Surface Experiments Package) measurements as well as astronaut and LADEE (Lunar Atmosphere and Dust Environment Explorer) orbital observations and laboratory experiments possibly suggest that a fine fraction of dust is levitated and moves across and above the lunar surface. Over millions of years such dust might be expected to coat all exposed rock surfaces. This study uses thermal modeling, combined with Diviner (a Lunar Reconnaissance Orbiter experiment) orbital lunar eclipse temperature data, to further document the existence of bare rocks on the lunar surface.

Hydrocarbon potential of Ordovician and Silurian rocks. Siljan Region (Sweden)

Energy Technology Data Exchange (ETDEWEB)

Berner, U. [Bundesanstalt fuer Geowissenschaften und Rohstoffe (BGR), Hannover (Germany); Lehnert, O. [Erlangen-Nuernberg Univ., Erlangen (Germany); Meinhold, G. [Goettingen Univ. (Germany)

2013-08-01

Hydrocarbon exploration in the vicinity of Europe's largest impact structure (Siljan, Central Sweden) focused for years on abiogenic concepts and largely neglected state of the art knowledge on hydrocarbon generation via thermal decomposition of organic matter. In our study we use sedimentary rocks obtained from three drill sites (Mora001, Stumsnaes 1 and Solberga 1) within the ring structure around the central uplift to investigate the hydrocarbon potential of Ordovician and Silurian strata of the region and also for comparison with the shale oil and gas potential of age equivalent rocks of the Baltic Sea. Elemental analyses provided information on concentrations of carbonate and organic carbon, total sulfur as well as on the composition of major and minor elements of the sediments. The data has been used to evaluate the depositional environment and possible diagenetic alterations of the organic matter. RockEval pyrolysis and solvent hydrocarbon extraction gave insight into the hydrocarbon generation potential and the type and thermal maturity of the sediments. From the geochemistry data of the studied wells it is obvious that changes of depositional environments (lacustrine - marine) have occurred during Ordovician and Silurian times. Although, the quality of the organic matter has been influenced in marine and brackish environments through sulfate reduction, we observe for a number of marine and lacustrine sediments a good to excellent preservation of the biological precursors which qualify the sediments as hydrocarbon source rocks (Type II kerogens). Lacustrine source rocks show a higher remaining hydrocarbon potential (up to {proportional_to}550 mg HC per g C{sub org}) than those of marine or brackish environments. Our investigations indicate that the thermal maturity of organic matter of the drill sites has reached the initial stage of oil generation. However, at Mora001 some of the sediments were stained with oil indicating that hydrocarbons have

The effects of bacteria on crystalline rock

International Nuclear Information System (INIS)

Brown, D.A.

1994-01-01

Many reactions involving inorganic minerals at water-rock interfaces have now been recognized to be bacterially mediated; these reactions could have a significant effect in the excavation of vaults for toxic and radioactive waste disposal. To investigate the role that bacteria play in the natural aqueous environment of crystalline rock the microbial growth factors of nutrition, energy and environment are described. Microbial activity has been investigated in Atomic Energy of Canada's Underground Research Laboratory (URL), situated in the Archean granitic Lac du Bonnet Batholith, Winnipeg, Manitoba. Faults, initiated in the Early Proterozoic, and later-formed fractures, provide ground-water pathways. Planktonic bacteria, free-swimming in the groundwater, have been observed in over 100 underground borehole samples. The number of bacteria varied from 10 3 to 10 5 mL -1 and appeared to decrease with depth and with increased salinity of the water. However, in the natural environment of deep (100-500 m) crystalline rocks, where nutrition is limited, formation of biofilms by sessile bacteria is a successful survival strategy. Natural biofilms at the URL and biofilms grown in bioreactors have been studied. The biofilms can accumulate different elements, depending upon the local environment. Precipitates of iron have been found in all the biofilms studied, where they are either passively accumulated or utilized as an energy source. Within the biofilm active and extensive biogeochemical immobilization of dissolved elements is controlled by distinct bacterial activities which are sufficiently discrete for hematite and siderite to be precipitated in close proximity

Sinkhole susceptibility in carbonate rocks of the Apulian karst (southern Italy)

Science.gov (United States)

Di Santo, Antonio; Fazio, Nunzio L.; Fiore, Antonio; Lollino, Piernicola; Luisi, Michele; Miccoli, Maria N.; Pagliarulo, Rosa; Parise, Mario; Perrotti, Michele; Pisano, Luca; Spalluto, Luigi; Vennari, Carmela; Vessia, Giovanna

2016-04-01

modelling the instability processes, and the development of charts for a preliminary evaluation of the stability of underground caves. Two distinct approaches were established to take into account the different petrographic, structural and geotechnical features of both the hard and soft carbonate rocks. The approach dealing with hard carbonate rocks (where natural karst caves develop) is based on speleological and geometrical surveys of the caves and on an integrated geological and geomechanical characterization of the carbonate rock mass, aimed at individuating the main critical aspects of the karst caves in terms of likely effects on the society. On the other hand, the approach to verify the stability of soft rocks where artificial cavities have been excavated is mostly dependent upon the peculiar petrographic and geomechanical characteristics of the calcarenite rock mass, typically massive and unaffected by tectonic discontinuities. As a consequence, the traditional analytical methods of rock mass classification fail in these materials, since the rock strength of soft calcarenites is mostly dependent upon sediment texture, porosity type and distribution and degree of cementation. The fluid circulation into the rock mass is also important because the removal of the rock matrix may induce a rapid deterioration of the mechanical behaviour of the rock mass. The approach to the calcarenite is mostly based on the characterization of petrographic and geotechnical parameters by means of direct sampling from the rock walls and in situ surveys (wells, trenches, etc.). Through implementation of the two approaches, our goal is to reconstruct accurate geometrical, geological and geotechnical models for both natural caves and artificial cavities. These models will be useful also to plan specific monitoring activities in order to understand the development of underground instability, and the related evolution through the rock mass, possibly threatening the urban areas and

In Situ Experiment and Numerical Model Validation of a Borehole Heat Exchanger in Shallow Hard Crystalline Rock

Directory of Open Access Journals (Sweden)

Mateusz Janiszewski

2018-04-01

Full Text Available Accurate and fast numerical modelling of the borehole heat exchanger (BHE is required for simulation of long-term thermal energy storage in rocks using boreholes. The goal of this study was to conduct an in situ experiment to validate the proposed numerical modelling approach. In the experiment, hot water was circulated for 21 days through a single U-tube BHE installed in an underground research tunnel located at a shallow depth in crystalline rock. The results of the simulations using the proposed model were validated against the measurements. The numerical model simulated the BHE’s behaviour accurately and compared well with two other modelling approaches from the literature. The model is capable of replicating the complex geometrical arrangement of the BHE and is considered to be more appropriate for simulations of BHE systems with complex geometries. The results of the sensitivity analysis of the proposed model have shown that low thermal conductivity, high density, and high heat capacity of rock are essential for maximising the storage efficiency of a borehole thermal energy storage system. Other characteristics of BHEs, such as a high thermal conductivity of the grout, a large radius of the pipe, and a large distance between the pipes, are also preferred for maximising efficiency.

Revisiting the definition of local hardness and hardness kernel.

Science.gov (United States)

Polanco-Ramírez, Carlos A; Franco-Pérez, Marco; Carmona-Espíndola, Javier; Gázquez, José L; Ayers, Paul W

2017-05-17

An analysis of the hardness kernel and local hardness is performed to propose new definitions for these quantities that follow a similar pattern to the one that characterizes the quantities associated with softness, that is, we have derived new definitions for which the integral of the hardness kernel over the whole space of one of the variables leads to local hardness, and the integral of local hardness over the whole space leads to global hardness. A basic aspect of the present approach is that global hardness keeps its identity as the second derivative of energy with respect to the number of electrons. Local hardness thus obtained depends on the first and second derivatives of energy and electron density with respect to the number of electrons. When these derivatives are approximated by a smooth quadratic interpolation of energy, the expression for local hardness reduces to the one intuitively proposed by Meneses, Tiznado, Contreras and Fuentealba. However, when one combines the first directional derivatives with smooth second derivatives one finds additional terms that allow one to differentiate local hardness for electrophilic attack from the one for nucleophilic attack. Numerical results related to electrophilic attacks on substituted pyridines, substituted benzenes and substituted ethenes are presented to show the overall performance of the new definition.

Reference waste package environment report

International Nuclear Information System (INIS)

Glassley, W.E.

1986-01-01

One of three candidate repository sites for high-level radioactive waste packages is located at Yucca Mountain, Nevada, in rhyolitic tuff 700 to 1400 ft above the static water table. Calculations indicate that the package environment will experience a maximum temperature of ∼230 0 C at 9 years after emplacement. For the next 300 years the rock within 1 m of the waste packages will remain dehydrated. Preliminary results suggest that the waste package radiation field will have very little effect on the mechanical properties of the rock. Radiolysis products will have a negligible effect on the rock even after rehydration. Unfractured specimens of repository rock show no change in hydrologic characteristics during repeated dehydration-rehydration cycles. Fractured samples with initially high permeabilities show a striking permeability decrease during dehydration-rehydration cycling, which may be due to fracture healing via deposition of silica. Rock-water interaction studies demonstrate low and benign levels of anions and most cations. The development of sorptive secondary phases such as zeolites and clays suggests that anticipated rock-water interaction may produce beneficial changes in the package environment

Fault Rock Zones Characterisation - Final report. TRUE-1 Continuation Project

International Nuclear Information System (INIS)

Winberg, Anders

2010-11-01

At the conclusion of the TRUE-1 and TRUE Block Scale experimental programmes at the Aespoe Hard Rock Laboratory one remaining identified uncertainty was the in situ internal structure of conductive structures, and in particular the in situ material properties of unconsolidated fault gouge of such conductive structures. With the aim of reducing these uncertainties an experimental program has been conducted at depth in the Aespoe Hard Rock Laboratory. Four conductive structures in the immediate vicinity of the Aespoe tunnel were identified for further study. Following basic geometrical and geological modelling based on tunnel observations, geological/ mineralogical and hydrogeological investigations in four boreholes at each site, epoxy resin was injected in selected packed off borehole sections containing the structure. Following a sufficient time for curing of the epoxy, the injected borehole 72 mm sections were overcored with a 300 mm core barrel. Customised techniques were employed to section the core in the borehole and for its retrieval out of the borehole. Following basic geological mapping, selected overcores were sectioned and were subject to image analysis to assess the pore structure using a variety of different descriptive geometrical attributes. In addition, an attempt was made to infer the porosity of the fault rock (including fault gouge) using binary images. Since analysis has been made on multiple slices of impregnated rock it is also possible to crudely map the 3D variability of a given entity. It was furthermore identified that porosity estimates, which range from some 10-70% are, apart from being dependent on the penetration of the epoxy, dependent on the resolution of the given image, the size of the averaging window, and the porosity components contained therein. The obtained quantifications of porosity can therefore only be regarded as ball-park relative porosities of a complete fault rock zones. It does not, however, provide firm

Fault Rock Zones Characterisation - Final report. TRUE-1 Continuation Project

Energy Technology Data Exchange (ETDEWEB)

Winberg, Anders (ed.) (Conterra AB (Sweden))

2010-11-15

At the conclusion of the TRUE-1 and TRUE Block Scale experimental programmes at the Aespoe Hard Rock Laboratory one remaining identified uncertainty was the in situ internal structure of conductive structures, and in particular the in situ material properties of unconsolidated fault gouge of such conductive structures. With the aim of reducing these uncertainties an experimental program has been conducted at depth in the Aespoe Hard Rock Laboratory. Four conductive structures in the immediate vicinity of the Aespoe tunnel were identified for further study. Following basic geometrical and geological modelling based on tunnel observations, geological/ mineralogical and hydrogeological investigations in four boreholes at each site, epoxy resin was injected in selected packed off borehole sections containing the structure. Following a sufficient time for curing of the epoxy, the injected borehole 72 mm sections were overcored with a 300 mm core barrel. Customised techniques were employed to section the core in the borehole and for its retrieval out of the borehole. Following basic geological mapping, selected overcores were sectioned and were subject to image analysis to assess the pore structure using a variety of different descriptive geometrical attributes. In addition, an attempt was made to infer the porosity of the fault rock (including fault gouge) using binary images. Since analysis has been made on multiple slices of impregnated rock it is also possible to crudely map the 3D variability of a given entity. It was furthermore identified that porosity estimates, which range from some 10-70% are, apart from being dependent on the penetration of the epoxy, dependent on the resolution of the given image, the size of the averaging window, and the porosity components contained therein. The obtained quantifications of porosity can therefore only be regarded as ball-park relative porosities of a complete fault rock zones. It does not, however, provide firm

Thermal Inertia of Rocks and Rock Populations

Science.gov (United States)

Golombek, M. P.; Jakosky, B. M.; Mellon, M. T.

2001-01-01

The effective thermal inertia of rock populations on Mars and Earth is derived from a model of effective inertia versus rock diameter. Results allow a parameterization of the effective rock inertia versus rock abundance and bulk and fine component inertia. Additional information is contained in the original extended abstract.

Phosphatic Permian rocks of the Adobe Range, Nevada, and their environment of deposition

Science.gov (United States)

Ketner, Keith Brindley

1979-01-01

Permian sedimentary rocks in the Adobe range, northern Nevada, are phosphatic, and although the particles of phosphate are relatively more disseminated, they closely resemble the rocks of the Phosphoria Formation. In the northern Adobe Range, where the entire Permian sequence is approximately correlative with the Phosphoria Formation, it is 200 m thick and averages 1.7 percent P2O5 . In the southern Adobe Range, the Permian sequence is more than 1,700 m thick, and the upper half which is roughly correlative with the Phosphoria Formation averages more than 2 percent P2O5. Some thin beds in rocks of Permian age contain more than 20 percent P2O5. Phosphatic rocks of the Adobe Range were deposited in shallow water among islands in the western part of the epicontinental Phosphoria sea. The continental margin and the open ocean lay far to the west. At the same time, the Phosphoria Formation was being deposited in the eastern and central parts of the Phosphoria sea. Theories based on the work of Kasakov done in 1937 relating phosphate deposition directly to sites of upwelling oceanic waters are questioned. Nondeposition of diluent materials such as detritus and carbonate is probably of more importance in producing phosphate in economic concentrations than is geographic position with respect to upwelling waters.

BEM-DDM modelling of rock damage and its implications on rock laboratory strength and in-situ stresses

International Nuclear Information System (INIS)

Matsui, Hiroya

2008-03-01

Within the framework of JAEA's Research and Development on deep geological environments for assessing the safety and reliability of the disposal technology for nuclear waste, this study was conducted to determine the effects of sample damage on the strength obtained from laboratory results (uniaxial compression and Brazilian test). Results of testing on samples of Toki granite taken at Shobasama and at the construction site for the Mizunami Underground Research Laboratory (MIU) at Mizunami, Gifu Pref., Japan, were analysed. Some spatial variation of the results along the boreholes suggested the presence of a correlation between the laboratory strength and the in-situ stresses measured by means of the hydro-fracturing method. To confirm this, numerical analyses of the drilling process in brittle rock by means of a BEM-DDM program (FRACOD 2D ) were carried out to study the induced fracture patterns. These fracture patterns were compared with similar results reported by other published studies and were found to be realistic. The correlation between strength and in-situ stresses could then be exploited to estimate the stresses and the location of core discing observed in boreholes where stress measurements were not available. A correction of the laboratory strength results was also proposed to take into account sample damage during drilling. Modelling of Brazilian tests shows that the calculated fracture patterns determine the strength of the models. This is different from the common assumption that failure occurs when the uniform tensile stress in the sample reaches the tensile strength of the rock material. Based on the modelling results, new Brazilian tests were carried out on samples from borehole MIZ-1 that confirmed the failure mechanism numerically observed. A numerical study of the fracture patterns induced by removal of the overburden on a large scale produces fracture patterns and stress distributions corresponding to observations in crystalline hard rock in

Cataclastic effects in rock salt laboratory and in situ measurements

International Nuclear Information System (INIS)

Gramberg, J.; Roest, J.P.A.

1984-01-01

The aim of the research is the determination of eventual cataclastic effects in environmental rock salt of a heated part of a vertical deep test bore hole, a model for HLW disposal. Known cataclastic systems from hard rock mining and rock salt mines will form the starting point for the explanation of convergence of underground cavity walls. In rock salt, however, different elements seem to prevail: crystal plasticity and micro-cataclasis. The environmental measurements at the deep bore hole have to be carried out from a distance. To this end the acoustic micro-seismic method will be a suitable one. The appropriate equipment for micro-seismic cross hole measurement is designed, constructed and tested in the laboratory as well as underground. Acoustic velocity data form a crucial point. A micro-seismic acoustic P-wave model, adapted to the process of structural changes, is developed. P-wave velocity measurements in rock salt cubes in the laboratory are described. An underground cross hole measurement in the wall of a gallery with semi-circular section is treated and analysed. A conclusion was that, in this case, no macro-cataclasis (systematic large fractures) will be involved in the process of gallery convergence, but that the mechanism proved to be a combination of crystal plasticity and micro-cataclasis. The same mechanism might be expected to be present in the environmental rock salt of the HLW-disposal deep bore hole. As a result this environmental rock salt might be expected to be impermeable. A plan for the application of the developed equipment during the heating test on the ECN-deep-bore-hole is shown. A theory on ''disking'' or ''rim cracks'' is presented in an annex

Compact rock material gas permeability properties

Energy Technology Data Exchange (ETDEWEB)

Wang, Huanling, E-mail: whl_hm@163.com [Key Laboratory of Coastal Disaster and Defence, Ministry of Education, Hohai University, Nanjing 210098 (China); LML, University of Lille, Cite Scientifique, 59655 Villeneuve d’Ascq (France); Xu, Weiya; Zuo, Jing [Institutes of Geotechnical Engineering, Hohai University, Nanjing 210098 (China)

2014-09-15

Natural compact rocks, such as sandstone, granite, and rock salt, are the main materials and geological environment for storing underground oil, gas, CO{sub 2,} shale gas, and radioactive waste because they have extremely low permeabilities and high mechanical strengths. Using the inert gas argon as the fluid medium, the stress-dependent permeability and porosity of monzonitic granite and granite gneiss from an underground oil storage depot were measured using a permeability and porosity measurement system. Based on the test results, models for describing the relationships among the permeability, porosity, and confining pressure of rock specimens were analyzed and are discussed. A power law is suggested to describe the relationship between the stress-dependent porosity and permeability; for the monzonitic granite and granite gneiss (for monzonitic granite (A-2), the initial porosity is approximately 4.05%, and the permeability is approximately 10{sup −19} m{sup 2}; for the granite gneiss (B-2), the initial porosity is approximately 7.09%, the permeability is approximately 10{sup −17} m{sup 2}; and the porosity-sensitivity exponents that link porosity and permeability are 0.98 and 3.11, respectively). Compared with moderate-porosity and high-porosity rocks, for which φ > 15%, low-porosity rock permeability has a relatively lower sensitivity to stress, but the porosity is more sensitive to stress, and different types of rocks show similar trends. From the test results, it can be inferred that the test rock specimens’ permeability evolution is related to the relative particle movements and microcrack closure.

UK modelling of thermal effects on leakage from hard rock depositories

International Nuclear Information System (INIS)

Bourke, P.J.

1980-01-01

Thermally induced stress through and around depositories have been calculated assuming the rock to have constant mechanical properties obtained from laboratory measurements and ignoring the effects of existing fractures. After allowing for probable values of the natural stress field, regions of net tension and high shear stress which might cause new fractures were found. This analysis is, however, not yet considered to be reliable because of uncertainty about the above assumptions. Further, even if it is accurate, it is incomplete because it is still not possible to relate quantitatively calculated stresses to changes in permeability and porosity due to changes in existing fractures or initiation of new ones. Accordingly, further theoretical work is being done to plan an underground study of the effects of heating on a well defined fracture. Measurements of strain and modulus will be made to investigate the validity of the mechanical assumptions and hydraulic data will be obtained to relate stress to resistance to flow. It is hoped that further analysis will then allow an assessment of the importance of thermal stress around a depository to be made

Underground nuclear explosion effects in granite rock fracturing

International Nuclear Information System (INIS)

Derlich, S.

1970-01-01

On the Saharan nuclear test site in Hoggar granite, mechanical properties of the altered zones were studied by in situ and laboratory measurements. In situ methods of study are drillings, television, geophysical and permeability measurements. Fracturing is one of the most important nuclear explosion effects. Several altered zones were identified. There are: crushed zone, fractured zone and stressed zone. Collapse of crushed and fractured zone formed the chimney. The extent of each zone can be expressed in terms of yield and of characteristic parameters. Such results are of main interest for industrial uses of underground nuclear explosives in hard rock. (author)

Underground nuclear explosion effects in granite rock fracturing

Energy Technology Data Exchange (ETDEWEB)

Derlich, S [Commissariat a l' Energie Atomique, Centre d' Etude de Bruyeres-le-Chatel (France)

1970-05-01

On the Saharan nuclear test site in Hoggar granite, mechanical properties of the altered zones were studied by in situ and laboratory measurements. In situ methods of study are drillings, television, geophysical and permeability measurements. Fracturing is one of the most important nuclear explosion effects. Several altered zones were identified. There are: crushed zone, fractured zone and stressed zone. Collapse of crushed and fractured zone formed the chimney. The extent of each zone can be expressed in terms of yield and of characteristic parameters. Such results are of main interest for industrial uses of underground nuclear explosives in hard rock. (author)

Aespoe Hard Rock Laboratory Canister Retrieval Test. Microorganisms in buffer from the Canister Retrieval Test - numbers and metabolic diversity

International Nuclear Information System (INIS)

Lydmark, Sara; Pedersen, Karsten

2011-03-01

'Canister Retrieval Test' (CRT) is an experiment that started at Aespoe Hard Rock Laboratory (HRL) 2000. CRT is a part of the investigations which evaluate a possible KBS-3 storage of nuclear waste. The primary aim was to see whether it is possible or not to retrieve a copper canister after storage under authentic KBS-3 conditions. However, CRT also provided a unique opportunity to investigate if bacteria survived in the bentonite buffer during storage. Therefore, in connection to the retrieval of the canister microbiological samples were extracted from the bentonite buffer and the bacterial composition was studied. In this report, microbiological analyses of a total of 66 samples at the C2, R10, R9 and R6 levels in the bentonite from CRT are presented and discussed. By culturing bacteria from the bentonite in specific media the following bacterial parameters were investigated: The total amount of culturable heterotrophic aerobic bacteria, sulphate-reducing bacteria, and bacteria that produce the organic compound acetate (acetogens). The biovolume in the bentonite was determined by detection of the ATP content. In addition, bacteria from the bentonite were cultured in different sulphate-reducing media. In these cultures, the presence of the biotic compounds sulphide and acetate was investigated, since these have potentially negative effect on the copper canister in a KBS-3 repository. The results were to some extent compared to density, water content, and temperature data provided by Clay Technology AB. The results showed that 10 0 -10 2 viable sulphate-reducing and acetogenic bacteria and 10 2 -10 4 heterotrophic aerobic bacteria g -1 bentonite were present after five years of storage in the rock. Bacteria with several morphologies could be found in the cultures with bentonite. The most bacteria were detected in the bentonite buffer close to the rock but in a few samples also in bentonite close to the copper canister. When the presence of bacteria in the bentonite

Aespoe Hard Rock Laboratory Canister Retrieval Test. Microorganisms in buffer from the Canister Retrieval Test - numbers and metabolic diversity

Energy Technology Data Exchange (ETDEWEB)

Lydmark, Sara; Pedersen, Karsten (Microbial Analytics Sweden AB (Sweden))

2011-03-15

'Canister Retrieval Test' (CRT) is an experiment that started at Aespoe Hard Rock Laboratory (HRL) 2000. CRT is a part of the investigations which evaluate a possible KBS-3 storage of nuclear waste. The primary aim was to see whether it is possible or not to retrieve a copper canister after storage under authentic KBS-3 conditions. However, CRT also provided a unique opportunity to investigate if bacteria survived in the bentonite buffer during storage. Therefore, in connection to the retrieval of the canister microbiological samples were extracted from the bentonite buffer and the bacterial composition was studied. In this report, microbiological analyses of a total of 66 samples at the C2, R10, R9 and R6 levels in the bentonite from CRT are presented and discussed. By culturing bacteria from the bentonite in specific media the following bacterial parameters were investigated: The total amount of culturable heterotrophic aerobic bacteria, sulphate-reducing bacteria, and bacteria that produce the organic compound acetate (acetogens). The biovolume in the bentonite was determined by detection of the ATP content. In addition, bacteria from the bentonite were cultured in different sulphate-reducing media. In these cultures, the presence of the biotic compounds sulphide and acetate was investigated, since these have potentially negative effect on the copper canister in a KBS-3 repository. The results were to some extent compared to density, water content, and temperature data provided by Clay Technology AB. The results showed that 100-102 viable sulphate-reducing and acetogenic bacteria and 102-104 heterotrophic aerobic bacteria g-1 bentonite were present after five years of storage in the rock. Bacteria with several morphologies could be found in the cultures with bentonite. The most bacteria were detected in the bentonite buffer close to the rock but in a few samples also in bentonite close to the copper canister. When the presence of bacteria in the

[The elemental composition of teeth hard tissues depending on the state of the environment].

Science.gov (United States)

Suladze, N; Shishniashvili, T; Margvelashvili, V; Kobakhidze, K

2014-01-01

At present, great attention is paid to the origin of man-made micro elemental anomalies. To monitor the state of the environment and its effects on the human body, of great importance is the determination of the amount and distribution of various chemical elements in the dentin and enamel of the teeth. To determine the essential (Ca, Zn, Mn, Ni), conditionally essential (Rb, Ni, Sr) and toxic (Pb, Hg) trace elements in the mineralized tissues of the teeth and to identify the relationship between the elemental composition of the tooth structure and the state of the general and dental health depending on the state of the environment, we have examined 29 children aged 3-4 years who have carried out analysis of hard tissue of teeth (teeth used for remote medical reasons) for the maintenance of nine chemical elements. Children living in a relatively environmentally favorable conditions essential value and conditionally essential elements in the mineralized tissues of the teeth were within normal limits, and toxic elements slightly increased limits that differ from those of children living in environmentally disadvantaged areas. In particular, these essential elements were significantly reduced (except for zinc), as indicators of toxic elements - mercury and lead, increased by 12.5% and 44.5%, respectively, which is clearly reflected on the state of dental health because noted decompensated form of tooth decay. Thus, deviations in a state of general and dental health of children associated with an imbalance of macro-and microelements in the mineralized tissues of the teeth.

Organic petrology and geochemistry of Eocene Suzak bituminous marl, north-central Afghanistan: Depositional environment and source rock potential

Science.gov (United States)

Hackley, Paul C.; Sanfilipo, John

2016-01-01

Organic geochemistry and petrology of Eocene Suzak bituminous marl outcrop samples from Madr village in north-central Afghanistan were characterized via an integrated analytical approach to evaluate depositional environment and source rock potential. Multiple proxies suggest the organic-rich (TOC ∼6 wt.%) bituminous marls are ‘immature’ for oil generation (e.g., vitrinite Ro  1) indicating organic input from marine algae and/or bacterial biomass, and sterane/hopane ratios are low (0.12–0.14). Monoaromatic steroids are dominated by C28clearly indicating a marine setting. High gammacerane index values (∼0.9) are consistent with anoxia stratification and may indicate intermittent saline-hypersaline conditions. Stable C isotope ratios also suggest a marine depositional scenario for the Suzak samples, consistent with the presence of marine foraminifera including abundant planktic globigerinida(?) and rare benthic discocyclina(?) and nummulites(?). Biomarker 2α-methylhopane for photosynthetic cyanobacteria implies shallow photic zone deposition of Madr marls and 3β-methylhopane indicates presence of methanotrophic archaea in the microbial consortium. The data presented herein are consistent with deposition of Suzak bituminous marls in shallow stratified waters of a restricted marine basin associated with the southeastern incipient or proto-Paratethys. Geochemical proxies from Suzak rock extracts (S content, high polar content, C isotopes, normal (αααR) C27–29 steranes, and C29/C30 and C26/C25 hopane ratios) are similar to extant data from Paleogene oils produced to the north in the Afghan-Tajik Basin. This observation may indicate laterally equivalent strata are effective source rocks as suggested by previous workers; however, further work is needed to strengthen oil-source correlations.

Design and Analysis of Shock and Random Vibration Isolation of Operating Hard Disk Drive in Harsh Environment

Directory of Open Access Journals (Sweden)

Hendri Harmoko

2009-01-01

Full Text Available An effective vibration isolation system is important for hard disk drives (HDD used in a harsh mechanical environment. This paper describes how to design, simulate, test and evaluate vibration isolation systems for operating HDD subjected to severe shock and random vibrations based on military specifications MIL-STD-810E. The well-defined evaluation criteria proposed in this paper can be used to effectively assess the performance of HDD vibration isolation system. Design concepts on how to achieve satisfactory shock and vibration isolation for HDD are described. The concepts are tested and further enhanced by the two design case studies presented here. It is shown that an effective vibration isolation system, that will allow a HDD to operate well when subjected to severe shock and random vibration, is feasible.

True Triaxial Strength and Failure Modes of Cubic Rock Specimens with Unloading the Minor Principal Stress

Science.gov (United States)

Li, Xibing; Du, Kun; Li, Diyuan

2015-11-01

True triaxial tests have been carried out on granite, sandstone and cement mortar using cubic specimens with the process of unloading the minor principal stress. The strengths and failure modes of the three rock materials are studied in the processes of unloading σ 3 and loading σ 1 by the newly developed true triaxial test system under different σ 2, aiming to study the mechanical responses of the rock in underground excavation at depth. It shows that the rock strength increases with the raising of the intermediate principal stress σ 2 when σ 3 is unloaded to zero. The true triaxial strength criterion by the power-law relationship can be used to fit the testing data. The "best-fitting" material parameters A and n ( A > 1.4 and n plastic deformation. The maximum extension strain criterion Stacey (Int J Rock Mech Min Sci Geomech Abstr 651 18(6):469-474, 1981) can be used to explain the change of failure mode from shear to slabbing for strong and hard rocks under true triaxial unloading test condition.

Biodiversity of Rock Varnish at Yungay, Atacama Desert, Chile

Science.gov (United States)

Kuhlman, K.; Venkat, P.; La Duc, M.; Kuhlman, G.; McKay, C.

2007-12-01

Rock varnish is a very slow-growing nanostratigraphic coating consisting of approximately 70% clay and 30% iron and manganese oxides of fine-grained clay minerals rich in manganese and iron oxides, which forms on the surfaces of rocks in most semi-arid to hyper-arid climates. Rock varnish has even been postulated to exist on Mars based on surface imagery from several landed missions, and is considered a potential biomarker. However, the mechanism of varnish nucleation and growth remains unknown. Whether or not microbes are involved in the nucleation and growth of rock varnish, the detection of microbes using cultivation or cultivation- independent techniques has demonstrated that varnish provides a microhabitat for microbes. We hypothesized that rock varnish in the Mars-like Yungay region of the Atacama Desert may provide such a microhabitat for microbial life where none has been found to date in the surface soil (< 1 cm). The presence of microbes was investigated using adenosine triphosphate (ATP) assay techniques and culture-independent biomolecular methods. High levels of both total and intracellular ATP were associated with the rock varnish while negligible ATP was found in the surrounding surface soil, suggesting that viable organisms were present. Total DNA was extracted from ground varnish and surrounding surface soil and subjected to trifurcate polymerase chain reactions (PCR). No DNA was recovered from the soil. Amplicons were used to generate ribosomal DNA (rDNA) clone libraries, which suggest the presence of numerous phylogenetically distinct microorganisms in eight Eubacterial clades, Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Cytophaga-Flavobacterium- Bacteroides (CFB), Chloroflexi (green non-sulfur bacteria (GNS)), Gemmatimonadetes, Actinobacteria and Cyanobacteria. The diversity of bacteria found and presence of cyanobacteria suggests that rock varnish provides a niche environment for a cryptoendolithic microbial community where

Rock stability considerations for siting and constructing a KBS-3 repository. Based on experiences from Aespoe HRL, AECL's URL, tunnelling and mining

Energy Technology Data Exchange (ETDEWEB)

Martin, C.D. [Univ. of Alberta, Edmonton (Canada); Christiansson, Rolf [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Soederhaell, J. [VBB VIAK AB, Stockholm (Sweden)

2001-12-01

Over the past 25 years the international nuclear community has carried out extensive research into the deep geological disposal of nuclear waste in hard rocks. In two cases this research has resulted in the construction of dedicated underground research facilities: SKB's Aespoe Hard Rock Laboratory, Sweden and AECL's Underground Research Laboratory, Canada. Both laboratories are located in hard rocks considered representative of the Fennoscandian and Canadian Shields, respectively. This report is intended to synthesize the important rock mechanics findings from these research programs. In particular the application of these finding to assessing the stability of underground openings. As such the report draws heavily on the published results from the SKB's ZEDEX Experiment in Sweden and AECL's Mine- by Experiment in Canada. The objectives of this report are to: 1. Describe, using the current state of knowledge, the role rock engineering can play in siting and constructing a KBS-3 repository. 2. Define the key rock mechanics parameters that should be determined in order to facilitate repository siting and construction. 3. Discuss possible construction issues, linked to rock stability, that may arise during the excavation of the underground openings of a KBS-3 repository. 4. Form a reference document for the rock stability analysis that has to be carried out as a part of the design works parallel to the site investigations. While there is no unique or single rock mechanics property or condition that would render the performance of a nuclear waste repository unacceptable, certain conditions can be treated as negative factors. Outlined below are major rock mechanics issues that should be addressed during the siting, construction and closure of a nuclear waste repository in Sweden in hard crystalline rock. During the site investigations phase, rock mechanics information will be predominately gathered from examination and testing of the rock core and

Between a rock and a hard place: Management and implementation teams’ expectations of project managers in an agile information systems delivery environment

Directory of Open Access Journals (Sweden)

Songezo Nkukwana

2017-08-01

Objectives: This case study investigated how project managers could adapt to agile IS implementation environments to remain relevant. Specifically, the views of their key stakeholders (the management and implementation teams were elicited to provide insights into what is expected from agile project managers. Method: A qualitative, inductive content analysis approach using purposive sampling was used to identify 13 participants (comprising management and implementation team members within a large South African insurance company. Semi-structured interviews were conducted with all participants. Results: The management and implementation teams agreed that PM remains highly relevant in an agile environment for ensuring project governance including delivery, risk management, reporting and budgeting. There was, however, disagreement between the management and implementation teams on project management interaction with the implementation team. Management preferred a command and control type project manager, while the implementation team favoured a more inclusive, facilitative PM style. Conclusion: To remain viable in an agile IS project implementation environment within large corporates, project managers need to be aware of what various stakeholders expect of them. They need to retain some of the classic PM functions while adapting to the interpersonal and collaborative requirements of the agile way.

A revised conceptual hydrogeologic model of a crystalline rock environment, Whiteshell research area, southeastern Manitoba, Canada

International Nuclear Information System (INIS)

Stevenson, D.R.; Brown, A.; Davison, C.C.; Gascoyne, M.; McGregor, R.G.; Ophori, D.U.; Scheier, N.W.; Stanchell, F.; Thorne, G.A.; Tomsons, D.K.

1996-04-01

A revised conceptual hydrogeologic model of regional groundwater flow in the crystalline rocks of the Whiteshell Research Area (WRA) has been developed by a team of AECL geoscientists. The revised model updates an earlier model developed in 1985, and has a much broader database. This database was compiled from Landsat and airborne radar images, geophysical surveys and surface mapping, and from analyses of fracture logs, hydraulic tests and water samples collected from a network of deep boreholes drilled across the WRA. The boundaries of the revised conceptual model were selected to coincide with the natural hydraulic boundaries assumed for the regional groundwater flow systems in the WRA. The upper and lower boundaries are the water table and a horizontal plane 4 km below ground surface. For modelling purposes the rocks below 4 km are considered to be impermeable. The rocks of the modelled region were divided on the basis of fracture characteristics into three categories: fractured zones (FZs); moderately fractured rock (MFR); and sparsely fractured rock (SFR). The FZs are regions of intensely fractured rock. Seventy-six FZs were selected to form the fault framework within the revised conceptual model. The physical rock/water properties of the FZs, MFR and SFR were selected by analysis of field data from hydraulic and tracer tests, laboratory test data and water quality data. These properties were used to define a mathematical groundwater flow model of the WRA using AECL's MOTIF finite element code (Ophori et al. 1995, 1996). (author). 29 refs., 4 tabs., 12 figs

Classification and Distribution of Mars Pathfinder Rocks Using Quantitative Morphologic Indices

Science.gov (United States)

Yingst, R. A.; Biederman, K. L.; Monhead, A. M.; Haldemann, A. F. C.; Kowalczyk, M. R.

2004-01-01

The Mars Pathfinder (MPF) landing site was predicted to contain a broad sampling of rock types varying in mineralogical, physical, mechanical and geochemical characteristics. Although rocks have been divided into several spectral categories based on Imager for Mars Pathfinder visible/near-infrared spectra, it has not been fully determined which of these stem from intrinsic mineralogical differences between rocks or rock surfaces, and which result from factors such as physical or chemical weathering. This has made isolation of unique mineralogy's difficult. Efforts in isolating and classifying spectral units among MPF rocks and soils have met with varying degrees of success, and the current understanding is such that many factors influencing spectral signatures cannot be quantified to a sufficient level so they may be removed. The result is that fundamental questions regarding information needed to reveal the present and past interactions between the rocks and rock surfaces and the Martian environment remain unanswered. But it is possible to approach the issue of identifying distinct rock and rock surface types from a different angle.

The application of positron emission tomography to the study of mass transfer in fractured rock

International Nuclear Information System (INIS)

Gilling, D.; Jefferies, N.L.; Fowles, P.; Hawkesworth, M.R.; Parker, D.J.

1991-06-01

Water flow in hard rocks takes place dominantly in fractures. In order to predict the transport of dissolved radioelements through a fractured rock it is necessary to determine both the geometry of the fracture network and the hydraulic properties of the individual fractures. This paper describes a technique for studying mass transfer in a single fracture. The technique is positron emission tomography (PET) and it offers the potential for visualising quantitatively the migration of dissolved tracers. Preliminary experiments have been undertaken involving the flow of Na-22 and F-18 labelled solutions through artificial fractures. The results demonstrate that PET is well suited to this application. (author)

Tungsten abundances in some volcanic rocks

International Nuclear Information System (INIS)

Helsen, J.N.; Shaw, D.M.; Crocket, J.H.

1978-01-01

A radiochemical N.A.A. method was used to obtain new values on W distribution in some 125 volcanic rocks, mainly basalts and andesites, from different petrotectonic environments. These W data are below previously reported abundances. New median values in various types of rocks are suggested (ppm W). Basalts: ocean floor, 0.15; ocean islands subalkaline, 0.28; ocean islands alkaline, 0.60; island arc, 0.19; continental margin, 0.40; continental subalkaline, 0.30; continental alkaline, 1.35. Andesites: island arc, 0.23; continental margin, 1.05. Median values for all 91 basalts and all 20 andesites are 0.36 and 0.29 ppm respectively. (author)

Rock support for nuclear waste repositories

International Nuclear Information System (INIS)

Abramson, L.W.; Schmidt, B.

1984-01-01

The design of rock support for underground nuclear waste repositories requires consideration of special construction and operation requirements, and of the adverse environmental conditions in which some of the support is placed. While repository layouts resemble mines, design, construction and operation are subject to quality assurance and public scrutiny similar to what is experienced for nuclear power plants. Exploration, design, construction and operation go through phases of review and licensing by government agencies as repositories evolve. This paper discusses (1) the various stages of repository development; (2) the environment that supports must be designed for; (3) the environmental effects on support materials; and (4) alternative types of repository rock support

Rock stability considerations for siting and constructing a KBS-3 repository. Based on experiences from Aespoe HRL, AECL's URL, tunnelling and mining

International Nuclear Information System (INIS)

Martin, C.D.; Christiansson, Rolf; Soederhaell, J.

2001-12-01

Over the past 25 years the international nuclear community has carried out extensive research into the deep geological disposal of nuclear waste in hard rocks. In two cases this research has resulted in the construction of dedicated underground research facilities: SKB's Aespoe Hard Rock Laboratory, Sweden and AECL's Underground Research Laboratory, Canada. Both laboratories are located in hard rocks considered representative of the Fennoscandian and Canadian Shields, respectively. This report is intended to synthesize the important rock mechanics findings from these research programs. In particular the application of these finding to assessing the stability of underground openings. As such the report draws heavily on the published results from the SKB's ZEDEX Experiment in Sweden and AECL's Mine- by Experiment in Canada. The objectives of this report are to: 1. Describe, using the current state of knowledge, the role rock engineering can play in siting and constructing a KBS-3 repository. 2. Define the key rock mechanics parameters that should be determined in order to facilitate repository siting and construction. 3. Discuss possible construction issues, linked to rock stability, that may arise during the excavation of the underground openings of a KBS-3 repository. 4. Form a reference document for the rock stability analysis that has to be carried out as a part of the design works parallel to the site investigations. While there is no unique or single rock mechanics property or condition that would render the performance of a nuclear waste repository unacceptable, certain conditions can be treated as negative factors. Outlined below are major rock mechanics issues that should be addressed during the siting, construction and closure of a nuclear waste repository in Sweden in hard crystalline rock. During the site investigations phase, rock mechanics information will be predominately gathered from examination and testing of the rock core and mapping of the

Potential Cement Phases in Sedimentary Rocks Drilled by Curiosity at Gale Crater, Mars

Science.gov (United States)

Rampe, E. B.; Morris, R. V.; Bish, D. L.; Chipera, S. J.; Ming, D. W.; Blake, D. F.; Vaniman, D. T.; Bristow, T. F.; Cavanagh, P.; Farmer, J. D.;

Aespoe Hard Rock Laboratory. Final report of the first stage of the tracer retention understanding experiments

Energy Technology Data Exchange (ETDEWEB)

Winberg, A. [Conterra AB, Uppsala (Sweden); Andersson, Peter [Geosigma AB, Uppsala (Sweden); Hermanson, Jan [Golder Grundteknik, Solna (Sweden); Byegaard, Johan [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Nuclear Chemistry; Cvetkovic, V. [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Water Resources Engineering; Birgersson, Lars [Kemakta Konsult AB, Stockholm (Sweden)

2000-03-15

The first stage of the Tracer Retention Understanding Experiments (TRUE) was performed as a SKB funded project. The overall objectives of TRUE are to develop the understanding of radionuclide migration and retention in fractured rock, to evaluate the realism in applied model concepts, and to assess whether the necessary input data to the models can be collected from site characterisation. Further, to evaluate the usefulness and feasibility of different model approaches, and finally to provide in situ data on radionuclide migration and retention. The strive for address with multiple approaches is facilitated through a close collaboration with the Aespoe Task Force on Modelling of Groundwater Flow and Transport of Solutes. The TRUE programme is a staged programme which addresses various scales from laboratory (< 0.5 m), detailed scale (< 10 m) and block scale (10-50 m). The First TRUE Stage was performed in the detailed scale with the specific objectives of providing data and conceptualising the investigated feature using conservative and sorbing tracers. Further, to improve methodologies for performing tracer tests, and to develop and test a methodology for obtaining pore volume/aperture data from epoxy resin injection, excavation and subsequent analyses. The experimental site is located at approximately 400 m depth in the northeastern part of the Aespoe Hard Rock Laboratory. The identification of conductive fractures and the target feature has benefited from the use of BIPS borehole TV imaging combined with detailed flow logging. The assessment of the conductive geometry has been further sustained by cross-hole pressure interference data. The investigated target feature (Feature A) is a reactivated mylonite which has later undergone brittle deformation. The feature is oriented northwest, along the principal horizontal stress orientation, and is a typical conductor for Aespoe conditions. Hydraulic characterisation shows that the feature is relatively well isolated

Creep in jointed rock masses. State of knowledge

Energy Technology Data Exchange (ETDEWEB)

Glamheden, Rune (Golder Associates AB (Sweden)); Hoekmark, Harald (Clay Technology AB, Lund (Sweden))

2010-06-15

To describe creep behaviour in hard rock masses in a physically realistic way, elaborate models including various combinations of dash pots, spring elements and sliders would be needed. According to our knowledge, there are at present no numerical tools available that can handle such a creep model. In addition, there are no records over sufficient long time periods of tunnel convergence in crystalline rock that could be used to determine or calibrate values for the model parameters. A possible method to perform bounding estimates of creep movements around openings in a repository may be to use distinct element codes with standard built-in elasto-plastic models. By locally reducing the fracture shear strength near the underground openings a relaxation of fracture shear loads is reached. The accumulated displacements may then represent the maximum possible effects of creep that can take place in a jointed rock mass without reference to the actual time it takes to reach the displacements. Estimates based on results from analyses where all shear stresses are allowed to disappear completely will, however, be over-conservative. To be able to set up and analyse reasonably realistic numerical models with the proposed method, further assumptions regarding the creep movements and the creep region around the opening have to be made. The purpose of this report is to present support for such assumptions as found in the literature.

Creep in jointed rock masses. State of knowledge

International Nuclear Information System (INIS)

Glamheden, Rune; Hoekmark, Harald

2010-06-01

To describe creep behaviour in hard rock masses in a physically realistic way, elaborate models including various combinations of dash pots, spring elements and sliders would be needed. According to our knowledge, there are at present no numerical tools available that can handle such a creep model. In addition, there are no records over sufficient long time periods of tunnel convergence in crystalline rock that could be used to determine or calibrate values for the model parameters. A possible method to perform bounding estimates of creep movements around openings in a repository may be to use distinct element codes with standard built-in elasto-plastic models. By locally reducing the fracture shear strength near the underground openings a relaxation of fracture shear loads is reached. The accumulated displacements may then represent the maximum possible effects of creep that can take place in a jointed rock mass without reference to the actual time it takes to reach the displacements. Estimates based on results from analyses where all shear stresses are allowed to disappear completely will, however, be over-conservative. To be able to set up and analyse reasonably realistic numerical models with the proposed method, further assumptions regarding the creep movements and the creep region around the opening have to be made. The purpose of this report is to present support for such assumptions as found in the literature

An in situ test of vibrating wire stressmeters in granitic rock

International Nuclear Information System (INIS)

Spinney, M.H.

1990-02-01

An in situ test was conducted to assess the ability of vibrating-wire stressmeters to measure stress changes in hard, unfractured granitic rock at the Underground Research Laboratory (URL). Twelve vibrating-wire stressmeters installed ahead of the face and below floor grade of Room 205 were monitored during the excavation of Room 205. The results were compared with results from CSIRO hollow inclusion triaxial strain cells, USBM boreholes deformation gauge overcore tests done before and after excavation, and a two-dimensional numerical model

Groundwater-quality data in the Bear Valley and Selected Hard Rock Areas study unit, 2010: Results from the California GAMA Program

Science.gov (United States)

Mathany, Timothy M.; Belitz, Kenneth

2013-01-01

Groundwater quality in the 112-square-mile Bear Valley and Selected Hard Rock Areas (BEAR) study unit was investigated by the U.S. Geological Survey (USGS) from April to August 2010, as part of the California State Water Resources Control Board (SWRCB) Groundwater Ambient Monitoring and Assessment (GAMA) Program’s Priority Basin Project (PBP). The GAMA-PBP was developed in response to the California Groundwater Quality Monitoring Act of 2001 and is being conducted in collaboration with the SWRCB and Lawrence Livermore National Laboratory (LLNL). The BEAR study unit was the thirty-first study unit to be sampled as part of the GAMA-PBP. The GAMA Bear Valley and Selected Hard Rock Areas study was designed to provide a spatially unbiased assessment of untreated-groundwater quality in the primary aquifer system and to facilitate statistically consistent comparisons of untreated groundwater quality throughout California. The primary aquifer system is defined as the zones corresponding to the perforation intervals of wells listed in the California Department of Public Health (CDPH) database for the BEAR study unit. Groundwater quality in the primary aquifer system may differ from the quality in the shallow or deep water-bearing zones; shallow groundwater may be more vulnerable to surficial contamination. In the BEAR study unit, groundwater samples were collected from two study areas (Bear Valley and Selected Hard Rock Areas) in San Bernardino County. Of the 38 sampling sites, 27 were selected by using a spatially distributed, randomized grid-based method to provide statistical representation of the primary aquifer system in the study unit (grid sites), and the remaining 11 sites were selected to aid in the understanding of the potential groundwater-quality issues associated with septic tank use and with ski areas in the study unit (understanding sites). The groundwater samples were analyzed for organic constituents (volatile organic compounds [VOCs], pesticides and

Development of radiation hardness components for ITER remote maintenance

Energy Technology Data Exchange (ETDEWEB)

Obara, Kenjiro; Kakudate, Satoshi; Oka, Kiyoshi; Ito, Akira [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Yagi, Toshiaki; Morita, Yousuke

1998-04-01

In the ITER, in-vessel remote handling is required to assemble and maintain in-vessel components in DT operations. Since in-vessel remote handling systems must operate under intense gamma ray radiation exceeding 30 kGy/h, their components must have sufficiently high radiation hardness to allow maintenance long enough in ITER in-vessel environments. Thus, extensive radiation tests and quality improvement, including optimization of material compositions, have been conducted through the ITER R and D program to develop radiation hardness components that meet radiation doses from 10 to 100 MGy at 10 kGy/h. This paper presents the latest on radiation hardness component development conducted by the Japan Home Team as a contribution to the ITER. The remote handling components tested are categorized for use in robotic or viewing systems, or as common components. Radiation tests have been conducted on commercially available products for screening, on modified products, and on new products to improve the radiation hardness. (author)

Development of radiation hardness components for ITER remote maintenance

International Nuclear Information System (INIS)

Obara, Kenjiro; Kakudate, Satoshi; Oka, Kiyoshi; Ito, Akira; Yagi, Toshiaki; Morita, Yousuke

1998-01-01

In the ITER, in-vessel remote handling is required to assemble and maintain in-vessel components in DT operations. Since in-vessel remote handling systems must operate under intense gamma ray radiation exceeding 30 kGy/h, their components must have sufficiently high radiation hardness to allow maintenance long enough in ITER in-vessel environments. Thus, extensive radiation tests and quality improvement, including optimization of material compositions, have been conducted through the ITER R and D program to develop radiation hardness components that meet radiation doses from 10 to 100 MGy at 10 kGy/h. This paper presents the latest on radiation hardness component development conducted by the Japan Home Team as a contribution to the ITER. The remote handling components tested are categorized for use in robotic or viewing systems, or as common components. Radiation tests have been conducted on commercially available products for screening, on modified products, and on new products to improve the radiation hardness. (author)

Intra-terrestrial Biosorption of Radionuclides and Analogous Trace Elements. Microbial Interference with the 'Water/Rock Interface'

International Nuclear Information System (INIS)

Anderson, Craig

2005-12-01

The Swedish nuclear fuel management company (SKB) has instigated final site investigations for a deep subsurface high level nuclear waste (HLW) repository in granitic rock. This facility will be situated 500 meters below ground level and will isolate the HLW from the environment using an engineered multi-barrier system with a supposed design life of 10 5 to 10 6 years. As microbial life is ubiquitous in intra-terrestrial environments, assessing the subsurface geochemical and geomicrobial influences is critical for predicting the safety and longevity of HLW storage. In the possible event of repository failure, the transport of radionuclides through water conducting rock fractures is the predominant concern but radionuclide migration can be retarded by abiotic and biotic sorption processes. In this study biofilms were grown under in situ pressures and conditions using groundwater sourced from boreholes 296 m to 450m below sea level at the Aespoe hard rock laboratory (IM) in Sweden. Purpose built biofilm reactors were installed and left to develop microbial communities for up to one year. The community genera were then analysed genetically along with the population characteristics. Scintillation, NaI Y-detection, ICP-MS and autoradiography were used to investigate the ability of these biofilms to absorb trace metals from fracture fluids and synthetic groundwater containing Co, Pm, Np, Am, Th, U and Mo. The concentrations of PGE (platinum group elements) and REE (rare earth elements) were also measured by ICP-MS for experiments conducted in aerobic conditions. Results indicate that aerobic biofilms grown in near neutral pH conditions, with low pressure (1 bar) and oxygen (<1.5 mg/l; Eh <190 mV), can rapidly attenuate metals to over 1000-fold higher than the levels within the groundwater. In anaerobic conditions biofilms in 1.5 % salt and near neutral pH tend to favour the adsorption of the 3+ valence state (Am, Pm) over other radionuclides such as Co, Th, Np, U and Mo

Aespoe Hard Rock Laboratory. Prototype repository. Analyses of microorganisms, gases, and water chemistry in buffer and backfill, 2010

International Nuclear Information System (INIS)

Lydmark, Sara

2011-06-01

The prototype repository (hereafter, 'Prototype') is an international project to build and study a fullscale model of the planned Swedish final repository for spent nuclear fuel. However, the Prototype differs from a real storage in that it is drained, which makes the swelling pressure lower in the Prototype than in a real storage facility. The heat from the radioactive decay is simulated by electrical heaters. The project is being conducted at the Aespoe Hard Rock Laboratory (HRL) in crystalline rock at a depth of approximately 450 m. A monitoring programme is investigating the evolution of the water chemistry, gas, and microbial activity at the site, and a specific aim is to monitor the microbial consumption of oxygen in situ in the Prototype. This document describes the results of the analyses of microbes, gases, and chemistry inside the Prototype in 2010. Hydrogen, helium, nitrogen, oxygen, carbon monoxide, carbon dioxide, methane, ethane, and ethene were analysed at the following sampling points in the Prototype: KBU10001, KBU10002, KBU10004, KBU10008, and KFA04. Where the sampling points in the Prototype delivered pore water, the water was analysed for amount of ATP (i.e. the biovolume), culturable heterotrophic aerobic bacteria (CHAB), sulphate-reducing bacteria (SRB), methane-oxidizing bacteria (MOB), and iron-reducing bacteria (IRB). The pore water collected from the Prototype was subject to as many chemical analyses as the amount of water allowed. Chemical analyses were also performed on pore water from two additional sampling points, KBU10005 and KBU10006. Chemical data from a previous investigation of the groundwater outside the Prototype were compared with the pore water chemistry. The improved sampling and analysis protocols introduced in 2007 worked very well. The International Progress Report (IPR) 08-01 (Eriksson 2008) revealed that many of the hydrochemical sampling points differ greatly from each other. The 16 sampling points were therefore

Aespoe Hard Rock Laboratory. Prototype repository. Analyses of microorganisms, gases, and water chemistry in buffer and backfill, 2010

Energy Technology Data Exchange (ETDEWEB)

Lydmark, Sara [Microbial Analytics Sweden AB, Moelnlycke (Sweden)

2011-06-15

The prototype repository (hereafter, 'Prototype') is an international project to build and study a fullscale model of the planned Swedish final repository for spent nuclear fuel. However, the Prototype differs from a real storage in that it is drained, which makes the swelling pressure lower in the Prototype than in a real storage facility. The heat from the radioactive decay is simulated by electrical heaters. The project is being conducted at the Aespoe Hard Rock Laboratory (HRL) in crystalline rock at a depth of approximately 450 m. A monitoring programme is investigating the evolution of the water chemistry, gas, and microbial activity at the site, and a specific aim is to monitor the microbial consumption of oxygen in situ in the Prototype. This document describes the results of the analyses of microbes, gases, and chemistry inside the Prototype in 2010. Hydrogen, helium, nitrogen, oxygen, carbon monoxide, carbon dioxide, methane, ethane, and ethene were analysed at the following sampling points in the Prototype: KBU10001, KBU10002, KBU10004, KBU10008, and KFA04. Where the sampling points in the Prototype delivered pore water, the water was analysed for amount of ATP (i.e. the biovolume), culturable heterotrophic aerobic bacteria (CHAB), sulphate-reducing bacteria (SRB), methane-oxidizing bacteria (MOB), and iron-reducing bacteria (IRB). The pore water collected from the Prototype was subject to as many chemical analyses as the amount of water allowed. Chemical analyses were also performed on pore water from two additional sampling points, KBU10005 and KBU10006. Chemical data from a previous investigation of the groundwater outside the Prototype were compared with the pore water chemistry. The improved sampling and analysis protocols introduced in 2007 worked very well. The International Progress Report (IPR) 08-01 (Eriksson 2008) revealed that many of the hydrochemical sampling points differ greatly from each other. The 16 sampling points were

Estimating the Wet-Rock P-Wave Velocity from the Dry-Rock P-Wave Velocity for Pyroclastic Rocks

Science.gov (United States)

Kahraman, Sair; Fener, Mustafa; Kilic, Cumhur Ozcan

2017-07-01

Seismic methods are widely used for the geotechnical investigations in volcanic areas or for the determination of the engineering properties of pyroclastic rocks in laboratory. Therefore, developing a relation between the wet- and dry-rock P-wave velocities will be helpful for engineers when evaluating the formation characteristics of pyroclastic rocks. To investigate the predictability of the wet-rock P-wave velocity from the dry-rock P-wave velocity for pyroclastic rocks P-wave velocity measurements were conducted on 27 different pyroclastic rocks. In addition, dry-rock S-wave velocity measurements were conducted. The test results were modeled using Gassmann's and Wood's theories and it was seen that estimates for saturated P-wave velocity from the theories fit well measured data. For samples having values of less and greater than 20%, practical equations were derived for reliably estimating wet-rock P-wave velocity as function of dry-rock P-wave velocity.

Towards Practical Whitebox Cryptography: Optimizing Efficiency and Space Hardness

DEFF Research Database (Denmark)

Bogdanov, Andrey; Isobe, Takanori; Tischhauser, Elmar Wolfgang

2016-01-01

Whitebox cryptography aims to provide security for cryptographic algorithms in an untrusted environment where the adversary has full access to their implementation. Typical security goals for whitebox cryptography include key extraction security and decomposition security: Indeed, it should...... the practical requirements to whitebox cryptography in real-world applications such as DRM or mobile payments. Moreover, we formalize resistance towards decomposition in form of weak and strong space hardness at various security levels. We obtain bounds on space hardness in all those adversarial models...... real-world applications with whitebox cryptography....

Hard Copy Market Overview

Science.gov (United States)

Testan, Peter R.

1987-04-01

A number of Color Hard Copy (CHC) market drivers are currently indicating strong growth in the use of CHC technologies for the business graphics marketplace. These market drivers relate to product, software, color monitors and color copiers. The use of color in business graphics allows more information to be relayed than is normally the case in a monochrome format. The communicative powers of full-color computer generated output in the business graphics application area will continue to induce end users to desire and require color in their future applications. A number of color hard copy technologies will be utilized in the presentation graphics arena. Thermal transfer, ink jet, photographic and electrophotographic technologies are all expected to be utilized in the business graphics presentation application area in the future. Since the end of 1984, the availability of color application software packages has grown significantly. Sales revenue generated by business graphics software is expected to grow at a compound annual growth rate of just over 40 percent to 1990. Increased availability of packages to allow the integration of text and graphics is expected. Currently, the latest versions of page description languages such as Postscript, Interpress and DDL all support color output. The use of color monitors will also drive the demand for color hard copy in the business graphics market place. The availability of higher resolution screens is allowing color monitors to be easily used for both text and graphics applications in the office environment. During 1987, the sales of color monitors are expected to surpass the sales of monochrome monitors. Another major color hard copy market driver will be the color copier. In order to take advantage of the communications power of computer generated color output, multiple copies are required for distribution. Product introductions of a new generation of color copiers is now underway with additional introductions expected

Rock stress orientation measurements using induced thermal spalling in slim boreholes

International Nuclear Information System (INIS)

Hakami, Eva

2011-05-01

In the planning and design of a future underground storage for nuclear waste based on the KBS-3 method, one of the aims is to optimize the layout of deposition tunnels such that the rock stresses on the boundaries of deposition holes are minimized. Previous experiences from heating of larger scale boreholes at the Aespoe Hard Rock Laboratory (AHRL) gave rise to the idea that induced borehole breakouts using thermal loading in smaller diameter boreholes, could be a possible way of determining the stress orientation. Two pilot experiments were performed, one at the Aespoe Hard Rock Laboratory and one at ONKALO research site in Finland. An acoustic televiewer logger was used to measure the detailed geometrical condition of the borehole before and after heating periods. The acoustic televiewer gives a value for each 0.7 mm large pixel size around the borehole periphery. The results from the loggers are presented as images of the borehole wall, and as curves for the maximum, mean and minimum values at each depth. Any changes in the borehole wall geometry may thus be easily detected by comparisons of the logging result images. In addition, using an optical borehole televiewer a good and detailed realistic colour picture of the borehole wall is obtained. From these images the character of the spalls identified may be evaluated further. The heating was performed in a 4 m long section, using a heating cable centred in an 8 m deep vertical borehole, drilled from the floor of the tunnels. For the borehole in the Q-tunnel of AHRL the results from the loggings of the borehole before the heating revealed that breakouts existed even before this pilot test due to previous heating experiments at the site (CAPS). Quite consistent orientation and the typical shape of small breakouts were observed. After the heating the spalling increased slightly at the same locations and a new spalling location also developed at a deeper location in the borehole. At ONKALO three very small changes

Rock stress orientation measurements using induced thermal spalling in slim boreholes

Energy Technology Data Exchange (ETDEWEB)

Hakami, Eva [Geosigma AB, Uppsala (Sweden)

2011-05-15

In the planning and design of a future underground storage for nuclear waste based on the KBS-3 method, one of the aims is to optimize the layout of deposition tunnels such that the rock stresses on the boundaries of deposition holes are minimized. Previous experiences from heating of larger scale boreholes at the Aespoe Hard Rock Laboratory (AHRL) gave rise to the idea that induced borehole breakouts using thermal loading in smaller diameter boreholes, could be a possible way of determining the stress orientation. Two pilot experiments were performed, one at the Aespoe Hard Rock Laboratory and one at ONKALO research site in Finland. An acoustic televiewer logger was used to measure the detailed geometrical condition of the borehole before and after heating periods. The acoustic televiewer gives a value for each 0.7 mm large pixel size around the borehole periphery. The results from the loggers are presented as images of the borehole wall, and as curves for the maximum, mean and minimum values at each depth. Any changes in the borehole wall geometry may thus be easily detected by comparisons of the logging result images. In addition, using an optical borehole televiewer a good and detailed realistic colour picture of the borehole wall is obtained. From these images the character of the spalls identified may be evaluated further. The heating was performed in a 4 m long section, using a heating cable centred in an 8 m deep vertical borehole, drilled from the floor of the tunnels. For the borehole in the Q-tunnel of AHRL the results from the loggings of the borehole before the heating revealed that breakouts existed even before this pilot test due to previous heating experiments at the site (CAPS). Quite consistent orientation and the typical shape of small breakouts were observed. After the heating the spalling increased slightly at the same locations and a new spalling location also developed at a deeper location in the borehole. At ONKALO three very small changes

'Escher' Rock

Science.gov (United States)

2004-01-01

[figure removed for brevity, see original site] Chemical Changes in 'Endurance' Rocks [figure removed for brevity, see original site] Figure 1 This false-color image taken by NASA's Mars Exploration Rover Opportunity shows a rock dubbed 'Escher' on the southwestern slopes of 'Endurance Crater.' Scientists believe the rock's fractures, which divide the surface into polygons, may have been formed by one of several processes. They may have been caused by the impact that created Endurance Crater, or they might have arisen when water leftover from the rock's formation dried up. A third possibility is that much later, after the rock was formed, and after the crater was created, the rock became wet once again, then dried up and developed cracks. Opportunity has spent the last 14 sols investigating Escher, specifically the target dubbed 'Kirchner,' and other similar rocks with its scientific instruments. This image was taken on sol 208 (Aug. 24, 2004) by the rover's panoramic camera, using the 750-, 530- and 430-nanometer filters. The graph above shows that rocks located deeper into 'Endurance Crater' are chemically altered to a greater degree than rocks located higher up. This chemical alteration is believed to result from exposure to water. Specifically, the graph compares ratios of chemicals between the deep rock dubbed 'Escher,' and the more shallow rock called 'Virginia,' before (red and blue lines) and after (green line) the Mars Exploration Rover Opportunity drilled into the rocks. As the red and blue lines indicate, Escher's levels of chlorine relative to Virginia's went up, and sulfur down, before the rover dug a hole into the rocks. This implies that the surface of Escher has been chemically altered to a greater extent than the surface of Virginia. Scientists are still investigating the role water played in influencing this trend. These data were taken by the rover's alpha particle X-ray spectrometer.

Free-face-Assisted Rock Breaking Method Based on the Multi-stage Tunnel Boring Machine (TBM) Cutterhead

Science.gov (United States)

Geng, Qi; Wei, Zhengying; Meng, Hao; Macias, Francisco Javier; Bruland, Amund

2016-11-01

In order to improve the rock breaking efficiency of hard rock tunnel boring, many innovative rock breaking methods have been proposed (e.g., the water jet cutting, the high-power laser cutting, the impact-rotary drilling, and the undercutting method). However, most of the methods are not applicable to TBMs due to some structural reasons. Aiming on this problem, a free-face-assisted rock breaking method based on the multi-stage TBM cutterhead has been proposed. Series of proof-of-concept tests includes (1) the static compression test with vertical free face and (2) the rotary cutting tests in different free surface conditions were designed and carried out. The results show that the rock breaking force and efficiency can be significantly reduced and improved, respectively, with the assistance of the free face, due to the failure of the rock close to the free face is tensile-dominated failure. The influencing distance of the free face in the radial direction is at least 330 mm which covers about 5 disk cutters. Finally, the general structure of a small two-stage cutterhead (4 m in diameter) was tentatively designed in order to provide a possible approach to apply the free-face effect to TBMs.

Conducting Rock Mass Rating for tunnel construction on Mars

Science.gov (United States)

Beemer, Heidi D.; Worrells, D. Scott

2017-10-01

Mars analogue missions provide researchers, scientists, and engineers the opportunity to establish protocols prior to sending human explorers to another planet. This paper investigated the complexity of a team of simulation astronauts conducting a Rock Mass Rating task during Analogue Mars missions. This study was conducted at the Mars Desert Research Station in Hanksville, UT, during field season 2015/2016 and with crews 167,168, and 169. During the experiment, three-person teams completed a Rock Mass Rating task during a three hour Extra Vehicular Activity on day six of their two-week simulation mission. This geological test is used during design and construction of excavations in rock on Earth. On Mars, this test could be conducted by astronauts to determine suitable rock layers for tunnel construction which would provide explorers a permanent habitat and radiation shielding while living for long periods of time on the surface. The Rock Mass Rating system derives quantitative data for engineering designs that can easily be communicated between engineers and geologists. Conclusions from this research demonstrated that it is feasible for astronauts to conduct the Rock Mass Rating task in a Mars simulated environment. However, it was also concluded that Rock Mass Rating task orientation and training will be required to ensure that accurate results are obtained.

Measurement of hydrogeologic parameters of Indian volcanic rocks by sub-surface hydronuclear techniques

International Nuclear Information System (INIS)

Bardhan, M.

1977-01-01

Sub-surface hydronuclear techniques namely neutron-neutron, gamma-gamma and tracer dilution logging and single and double well tracer methods were adopted to investigate the hitherto inadequately studied hydrophysical properties of the Deccan lava flows which constitute the principal Indian volcanic suit of rocks. The hydrogeologic parameters measured in the field pertain to hydrostratigraphy, hydrostorage properties and geohydraulic characteristics of these layered hard formations. Results of the studies are presented and discussed briefly. (author)

Developing a Virtual Rock Deformation Laboratory

Science.gov (United States)

Zhu, W.; Ougier-simonin, A.; Lisabeth, H. P.; Banker, J. S.