WorldWideScience

Sample records for underhand longwall stope

  1. Longwall mining

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-03-14

    As part of EIA`s program to provide information on coal, this report, Longwall-Mining, describes longwall mining and compares it with other underground mining methods. Using data from EIA and private sector surveys, the report describes major changes in the geologic, technological, and operating characteristics of longwall mining over the past decade. Most important, the report shows how these changes led to dramatic improvements in longwall mining productivity. For readers interested in the history of longwall mining and greater detail on recent developments affecting longwall mining, the report includes a bibliography.

  2. Uranium Extraction by stope leaching

    International Nuclear Information System (INIS)

    Quan Aiguo; Li Yu; Li Congkui; Ouyang Jiangong

    1996-01-01

    The stope leaching is an effective way to extract uranium from hard rock deposit. On the basis of test results of uranium extracting by stope leaching at ore body number 30 in deposit 101 with combination of technological features of stope leaching, the analysis and comprehensive summary are emphasized on three key techniques-ore stacking in-place after blasting in stope, sprinkling of lixiviant and uranium recovery as well. These techniques will play an active role in developing stope leaching in China

  3. Algorithm of probabilistic assessment of fully-mechanized longwall downtime

    Science.gov (United States)

    Domrachev, A. N.; Rib, S. V.; Govorukhin, Yu M.; Krivopalov, V. G.

    2017-09-01

    The problem of increasing the load on a long fully-mechanized longwall has several aspects, one of which is the improvement of efficiency in using available stoping equipment due to the increase in coefficient of the machine operating time of a shearer and other mining machines that form an integral part of the longwall set of equipment. The task of predicting the reliability indicators of stoping equipment is solved by the statistical evaluation of parameters of downtime exponential distribution and failure recovery. It is more difficult to solve the problems of downtime accounting in case of accidents in the face workings and, despite the statistical data on accidents in mine workings, no solution has been found to date. The authors have proposed a variant of probability assessment of workings caving using Poisson distribution and the duration of their restoration using normal distribution. The above results confirm the possibility of implementing the approach proposed by the authors.

  4. Stope and Gully Support: Final report

    CSIR Research Space (South Africa)

    Roberts, MKC

    1995-12-01

    Full Text Available This project had two objectives namely: Develop a rationale for the design of stope support systems. Determine support resistance criteria for the support of stope gullies for both static and dynamic loading and develop improved support systems...

  5. Effective roof support for tabular stopes.

    CSIR Research Space (South Africa)

    Ottermann, RW

    2002-09-01

    Full Text Available on surface in the laboratory and in a mock-up stope. A risk analysis, in which technical, logistical and economical aspects were assessed, was done to determine the critical areas of the system. The tests and risk assessment of the roof support system... IN MOCK-UP STOPE............................................................................. 29 5.2.1 University of Pretoria mock-up stope......................................................29 5.2.2 Kloof mine mock-up stope...

  6. Alternative support systems for mechanized stopes

    CSIR Research Space (South Africa)

    Roberts, DP

    2005-05-01

    Full Text Available , it is not envisaged that such machines will cut in-stope pillars. This paper describes the alternative support systems that will replace the pillars and the stope geometries that will be required for this type of mining. The paper describes how the support resistance...

  7. Realistic dynamic stope support testing

    CSIR Research Space (South Africa)

    Ortlepp, WD

    2000-08-01

    Full Text Available mass of 10 000kg from a height of 3 metres to impact at a velocity of 7.7 m/s upon the target ‘rock mass’. The target mass was represented by a discontinuous but compact arrangement of steel-clad concrete blocks which would transmit and disperse... the concentrated impact load downward on to a collapsible roof. Carefully designed, shaped concrete blocks would represent the fractured hangingwall layer of the stope, the stability of which would be determined largely by the support system under test...

  8. Shrink stope design using an inventory model

    Directory of Open Access Journals (Sweden)

    D. Taylor

    2003-12-01

    Full Text Available This paper addresses the fact that current practice in shrink-stoping in hard rock mining invariably ignores the inventory holding cost of the blasted ore. We believe, and show by example, that ignoring this cost could make the difference between profit and loss in an industry that, at present, needs all the help it can get.

  9. Surface Mines, Other - Longwall Mining Panels

    Data.gov (United States)

    NSGIC Education | GIS Inventory — Coal mining has occurred in Pennsylvania for over a century. A method of coal mining known as Longwall Mining has become more prevalent in recent decades. Longwall...

  10. The new technology of dividing wall in stope

    International Nuclear Information System (INIS)

    Li Zhiguo

    1999-01-01

    The author analyzes advantages and disadvantages of the ordinary separating methods between stopes at deep mine, points out the main problems of the original projects constructing dividing wall, presents an idea of new technology which can overcome the main problems, predicts effect adopting the new technology, and analyzes that feasibility applying the new technology to construct mortar pad in stope and dyke-dam

  11. Application of short rockbolts in ultradeep tabular stoping

    CSIR Research Space (South Africa)

    Roberts, MKC

    2004-04-01

    Full Text Available Most rock related fatalities and injuries in South African gold mines occur in the stope face area. These mines generally do not use rockbolts to support this area. This paper describes short rockbolt applications in the stope face area in a narrow...

  12. Longwall top coal caving. The next challenge in longwall mining?

    Energy Technology Data Exchange (ETDEWEB)

    Humphries, P.; Kelly, M.; Poulsen, B. [CSIRO Exploration and Mining (Australia)

    2005-08-01

    This paper outlines the major challenges involved in implementing longwall top coal caving (LTCC) into Australian mines and provides a direction for tackling these issues through the use of proven scientific techniques and technological applications. Chinese knowledge and research on LTCC including ACARP project outcomes is used as a foundation for comparisons of Australian conditions and for highlighting the areas of required work for moving forward with an Australian LTCC operation. 6 refs., 10 figs., 1 tab.

  13. Longwall mining of thin seams

    Energy Technology Data Exchange (ETDEWEB)

    Curth, E A

    1981-01-01

    Thin seam operations pose a challenge to the ingenuity of mining engineers to overcome the factor of human inconvenience in the restricted environment and associated high cost production. Surprisingly, low seam longwalls in the Federal Republic of Germany in an average thickness of 35 in. and dipping less than 18/sup 0/ come close to achieving the average production rate of all German longwall operations. They are all plow faces, and a consistent production of 3300 tons per day and a productivity of 40 tons per man shift are reported from one of the thin seam longwalls. These results were attained by reliable high-capacity equipment and roof support by shields that can be collapsed to as low as 22 inches. Maximum mining height for plow operated faces lies at 31.5 inches. Technology for mechanized mining of flat lying coalbeds less than 31.5 inches in thickness without rock cutting is not available, and firmness of coal, undulation of the strata, coalbed thickness variation, and the necessity of cutting rock, particularly through faults, set limits to plow application. The in-web shearer can be used in firm coal to a minimum mining height of 40 inches, and a daily production of 1650 to 2200 tons is reported from a longwall in the Saar district of Germany equipped with such a shearer and shields. Numerous in-web shearers are employed in the United Kingdom; reports as to their success are contradictory. Also, experience in the United States, though limited, has been negative. The steady increase in output from single drum shearer faces in Pennsylvania is a remarkable achievement, and occasional record breaking peaks in production indicate the potential of such mining. Technology development for the future is discussed.

  14. Rock Mechanics Aspects of Stoping Without Back-area Support

    CSIR Research Space (South Africa)

    King, RG

    1989-06-01

    Full Text Available The report describes an experiment carried out at Hartebeesfontein Gold Mine, No. 6 Shaft, 77 N 25 Stope between October 1985 and November 1986, which involved mining two panels without back-area support and with different support resistances...

  15. Marie Stopes International Child Spacing Clinics in Malawi

    African Journals Online (AJOL)

    programme, male involvement has the following basic aspects: Initiation of dialogue on child spacing within the ... that men feel that child spacing is also their concern and service providers feel men are not outsiders. ... pioneering work of Marie Stopes in caring for women in the poor communities of London by extending the ...

  16. Impact of longwall mining on groundwater above the longwall panel in shallow coal seams

    Directory of Open Access Journals (Sweden)

    Yang Li

    2015-06-01

    Full Text Available Since longwall mining causes subsidence through the overlying strata to the ground surface, the surface water and groundwater above the longwall panels may be affected and drained into the lower levels. Therefore, loss or interruption of streams and overburden aquifers is a common concern in coal industry. This paper analyzed the potential effects of longwall mining on subsurface water system in shallow coal seam. In order to monitor different water level fluctuations throughout the mining period, three water wells were drilled down to the proposed deformation zone above the longwall panel. A GGU-SS-FLOW3D model was used to predict water table contours for the periods of pre- and post-mining conditions. The field data from the three water wells were utilized to calibrate the model. The field test and numerical model can help to better understand the dewatering of shallow aquifers and surface waters related to ground subsidence from longwall mining in shallow coal seam.

  17. Analysis of longwall face-to-face transfers

    International Nuclear Information System (INIS)

    Patrick, C.; Topuz, E.

    1992-01-01

    A non-producing longwall costs the mine owner from $45 to over $100 per minute in lost production time. Face-to-face equipment transfers, which involve disassembling longwall equipment in a panel, transporting, and then reassembling it in a new longwall panel, are second only to system availability as a source of longwall non-productive time. This, in addition to a move cost of over $100,000, makes reduction and control of face transfer times essential. This paper will report a segment of on-going VPI research to analyze and model longwall transfers through the use of operations research techniques. The purpose is to reduce overall transfer time and the variation of transfer times among U.S. longwall operations. This research is expected to contribute to the longwall mining industry by offering an objective approach that can be used in the prediction, planning, preparation, and implementation of longwall face equipment transfers

  18. Prism adaptation of underhand throwing: rotational inertia and the primary and latent aftereffects.

    Science.gov (United States)

    Blau, Julia J C; Stephen, Damian G; Carello, Claudia; Turvey, M T

    2009-06-05

    The effect of prism adaptation on movement is typically reduced when movement at test (with prisms removed) is different from movement at training. Previous research [J. Fernández-Ruiz, C. Hall-Haro, R. Díaz, J. Mischner, P. Vergara, J. C. Lopez-Garcia, Learning motor synergies makes use of information on muscular load, Learning & Memory 7 (2000) 193-198] suggests, however, that some adaptation is latent and only revealed through further testing in which the movement at training is fully reinstated. Movement in their training trials was throwing overhand to a vertical target with a mass attached to the arm. The critical test trials involved the same act initially without the attached mass and then with the attached mass. In replication, we studied throwing underhand to a horizontal target with left shifting prisms and a dissociation of the throwing arm's mass and moment of inertia. The two main results were that the observed latent aftereffect (a) depended on the similarity of training and test moments of inertia, and (b) combined with the primary aftereffect to yield a condition-independent sum. Discussion focused on a parallel between prism adaptation and principles governing recall highlighted in investigations of implicit memory: whether given training (study) conditions lead to good or poor persistence of adaptation (memory performance) at test depends on the conditions at test relative to the conditions at training (study).

  19. 30 CFR 75.813 - High-voltage longwalls; scope.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage longwalls; scope. 75.813 Section... AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution High-Voltage Longwalls § 75.813 High-voltage longwalls; scope. Sections 75.814 through 75.822 of this...

  20. 30 CFR 75.215 - Longwall mining systems.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Longwall mining systems. 75.215 Section 75.215... MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Roof Support § 75.215 Longwall mining systems. For each longwall mining section, the roof control plan shall specify— (a) The methods that will be used to maintain...

  1. Design of longwall mining system

    Energy Technology Data Exchange (ETDEWEB)

    Curth, E. A.

    1979-01-01

    A premining investigation includes core drill holes, seismic studies, satellite imagery and, where the underground is accessible, bearing strength tests of roof and floor, and residual stress determination. Longwall retreat is the preferred method in the USA. Exceptions are few. The objective of panel design is to maintain ground stability and to provide optimum resource recovery with the most cost-effective panel configuration. Environmental considerations, such as surface utilization, hydrology, oil and gas wells, affect panel location and layout. Roof support selection criteria stem from premining data. Prototype roof supports must satisfy an intensive testing program. Mining equipment, such as cutter loaders, face conveyors and stage loaders, is designed to match the production goal and anticipated face conditions. Coal clearance, power supply, men and supply transportation, communications, and equipment maintenance programs must be commensurate with the extraction potential. Face lighting must comply with mandatory standards. Operational monitoring and analysis include operational data extracted and summarized from shift and monthly records, and from ground control and subsidence observations.

  2. Mine safety sensors: Test results in a simulated test stope

    CSIR Research Space (South Africa)

    Dickens, J

    2013-10-01

    Full Text Available of the field of view of a thermal camera for identifying the entire extent of a loose rock in a narrow mine stope. Due to the field of view limitations of even wide-angle thermal cameras it is necessary to stitch together multiple image to get a full view... that are colder due to a fracture. To do this we compute: (1) a measure of flatness within a fixed radius, and (2) the coefficient of variation of temperature (CVT) within the same neighbourhood. The Fig. 5. The un-mounted 3D-thermal scanner flatness and the CVT...

  3. Top coal caving longwall maximizes thick seam recovery

    Energy Technology Data Exchange (ETDEWEB)

    Duncan, G.; Sobey,. G.; Clarke, T.

    2007-07-15

    Austar's longwall system offers opportunities in coal seams thicker than 4.5 meters. The Longwall Top Coal Caving (LTCC) method was recently launched in Australia at Yancoal Australia's Austar mines in Hunter Valley, although 90 such longwalls already operate in China. The article describes the method and its installation at Austar. In September 2006 the LTCC face commenced production. The operation is described and measures to prevent spontaneous combustion are outlined. Future work on the longwall is mentioned. 11 figs.

  4. Effects of Longwall subsidence on escarpment stability

    International Nuclear Information System (INIS)

    Shea-Albin, V.R.

    1992-01-01

    Increasing pressure from State and Federal agencies to mitigate mining-induced subsidence damage to overlying structures has presented a unique problem to the coal industry in the western United States. Because sandstone escarpments are an environmental issue, millions of tons of coal reserves that underlie these escarpments risk being classified as unminable by regulatory agencies. At this time, the effect of subsidence on escarpments has not been well documented or characterized. The Bureau of Mines is using numerical modeling techniques to analyze escarpment response to longwall mining. Two- and three-dimensional finite element models have been constructed for a study area near Price, Utah, where longwall panels were mined near an escarpment. This paper includes preliminary results showing that the pattern of subsidence surrounding the escarpment can be simulated through numerical modeling

  5. Special considerations for vibration analysis on longwall equipment

    Energy Technology Data Exchange (ETDEWEB)

    Towles, B.

    1996-12-31

    West Elk Mine has included vibration analysis as a part of the longwall maintenance program since 1993. Longwall equipment presents several special problems which are not common to most vibration analysis applications: (1) Heavy construction of equipment damps some signals making machine condition determinations difficult, and (2) Complexity of longwall equipment; (3) Difficulty in isolating spectrum frequencies to individual machinery components; (4) Flexing of equipment frames and housings due to longwall face advance affects vibration spectrums; (5) Difficulty of obtaining necessary information on internal machinery components from longwall equipment suppliers; (6) Permissibility of data collection instruments. In spite of these difficulties, West Elk has had positive results in preventing catastrophic failures, predicting life expectancy of failing components, making general machinery improvements in cooperation with manufacturers and determining rebuild quality.

  6. Numerical modeling for longwall pillar design: a case study from a typical longwall panel in China

    Science.gov (United States)

    Zhang, Guangchao; Liang, Saijiang; Tan, Yunliang; Xie, Fuxing; Chen, Shaojie; Jia, Hongguo

    2018-02-01

    This paper presents a new numerical modeling procedure and design principle for longwall pillar design with the assistance of numerical simulation of FLAC3D. A coal mine located in Yanzhou city, Shandong Province, China, was selected for this case study. A meticulously validated numerical model was developed to investigate the stress changes across the longwall pillar with various sizes. In order to improve the reliability of the numerical modeling, a calibration procedure is undertaken to match the Salamon and Munro pillar strength formula for the coal pillar, while a similar calibration procedure is used to estimate the stress-strain response of a gob. The model results demonstrated that when the coal pillar width was 7-8 m, most of the vertical load was carried by the panel rib, whilst the gateroad was overall in a relatively low stress environment and could keep its stability with proper supports. Thus, the rational longwall pillar width was set as 8 m and the field monitoring results confirmed the feasibility of this pillar size. The proposed numerical simulation procedure and design principle presented in this study could be a viable alternative approach for longwall pillar design for other similar projects.

  7. Stress analysis of longwall top coal caving

    Energy Technology Data Exchange (ETDEWEB)

    Alehossein, H.; Poulsen, B.A. [CSIRO Exploration & Mining, Brisbane, Qld. (Australia)

    2010-01-15

    Longwall top coal caving (LTCC) is a relatively new method of mining thick coal seams that is currently achieving high productivity and efficiency. The technique is similar to traditional longwall mining in that a cutting head slices coal from the lower section of the coal seam onto a conveyor belt installed in front of the hydraulic support near the cutting face. In modern LTCC an additional rear conveyor belt is located behind the support, to which the flow of the caved coal from the upper part of the seam can be controlled by a moveable flipper attached to the canopy of the support. The mining method relies on the fracturing of the top coal by the front abutment pressure to achieve satisfactory caving into the rear conveyor. This paper develops a yield and caveability criterion based on in situ conditions in the top coal in advance of the mining face (yield) and behind the supports (caveability). Yielding and caving effects are combined into one single number called caving number (CN), which is the multiplication result of caving factor (CF) and yield factor (YF). Analytical derivations are based on in situ stress conditions, Mohr-Coulomb and/or Hoek-Brown rock failure criteria and an on-associated elastoplastic strain softening material behaviour. The yield and caveability criteria are in agreement with results from both numerical studies and mine data. The caving number is normalised to mining conditions of a reference Chinese mine (LMX mine) and is used to assess LTCC performance at fourteen other Chinese working longwalls that have had varying success with the LTCC technology. As a predictive model, results of this analytical/numerical study are useful to assess the potential success of caving in new LTCC operations and in different mining conditions.

  8. Rock mechanics of crown pillars between cut-and-fill stopes at the Mount Isa mine

    Energy Technology Data Exchange (ETDEWEB)

    Lee, M.F.; Bridges, M.C.

    1980-05-15

    At both levels, the leading stopes experienced bad ground conditions due to high stresses in the stope's backs when the crown pillars were about 35 m high. At 9 level, cut-and-fill mining stopped and most of the crown pillars were extracted by a slot-and-massfire method. At 11 level, cut-and-fill mining continued. Shear displacement along bedding planes began within and around the crown pillars of the leading stopes at 11 level, and spread through other crown pillars and to the hangingwall of the stoping system. Destressing and good ground conditions occurred where shear occurred, with further concentrations of stress in other areas. Crown pillars are being extracted to leave minimal 1:2 height to width diaphragms under the stopes above. Ground behavior of the 11 level crown pillars was investigated by observation, stress measurement, regional surveying of displacement and finite element models. An explanation of the ground behavior has evolved from this work. Bedding planes with an estimated angle of sliding friction of 10/sup 0/ were the main factor determining the behavior of this area.

  9. Equipment for broken ore transport from stopes, mainly for radioactive ore transport

    International Nuclear Information System (INIS)

    Hejlik, V.; Strnadel, M.; Dostal, O.

    1975-01-01

    Equipment is described for the transport of broken ore from stopes, mainly of radioactive ores. The equipment is made from steel or plastics. It consists of a baseplate and of one or more centerings; it does not capture radioactive broken ores which improves the working environment in mines and increases safety of work. (Oy)

  10. Mapping seismic vulnerability in stopes in deep South African gold mines

    CSIR Research Space (South Africa)

    Durrheim, RJ

    2013-09-01

    Full Text Available mapping of faults, joints and mining-induced fractures; observations of mining practice and support performance; and mapping of rock falls and ejections. New technologies that are being developed for in-stope monitoring include an electronic sounding...

  11. Evaluate fundamental approaches to longwall dust control. Phase III report

    Energy Technology Data Exchange (ETDEWEB)

    Babbitt, C.; Bartlett, P.; Kelly, J.; Ludlow, J.; Mangolds, A.; Rajan, S.; Ruggieri, S.; Varga, E.

    1984-03-31

    The overall objective of the contract is to evaluate the effectiveness of available dust control technology for double-drum shearer longwall sections in a coordinated, systematic program at a few longwall test sections and to make the results available to the entire coal mining industry. This program is investigating nine different dust control techniques. These nine subprograms encompass a broad range of dust control measures ranging from administrative controls to new hardware. They span not only presently employed methods but also those recently adopted in the United States and those proposed for the future. This report documents the Phase III effort on each of the subprograms. For clarity, the report is divided in sections by subprogram as follows: Section 2, Subprogram A - passive barriers/spray air movers for dust control; Section 3, Subprogram B - practical aspects of deep cutting; Section 4, Subprogram C - stage loader dust control; Section 5, Subprogram D - longwall automation technology; Section 6, Subprogram E - longwall application of ventilation curtains; Section 7, Subprogram F - reversed drum rotation; Section 8, Subprogram G - reduction of shield generated dust; Section 9, Subprogram H - air canopies for longwalls; and Section 10, Subprogram I - mining practices. 43 figures, 11 tables.

  12. Subsidence interactions related to longwall mining of the upper and lower Kittanning coalbeds

    International Nuclear Information System (INIS)

    Chekan, G.J.; Bauer, E.R.

    1992-01-01

    The U.S. Bureau of Mines, in an effort to improve coal conservation and utilization, is currently investigating longwall panel layouts to maximize coal recovery and minimize interactive problems in multiple-seam operations. When longwalling coalbeds in ascending order, subsidence of the overlying strata is an interactive problem that may influence the stability of the gate roads and longwall panels in the upper mine. To control interactive problems, two fundamental design approaches involved either offsetting of superimposing the gate roads and longwall panels. This paper involves analytical predictions and underground observations of longwall development ground control problems at a south-central Pennsylvania coal mine where gate road superpositioning was practiced

  13. Control technique of spontaneous combustion in fully mechan ized stope during period of end caving under complex mining influence

    Science.gov (United States)

    Yuan, Benqing

    2018-01-01

    In view of the phenomenon of spontaneous combustion of coal seam occurring during the period of end caving under complex mining conditions, taking the 1116 (3) stope of Guqiao mine as the object of study, the causes of spontaneous combustion during the period of end caving are analyzed, according to the specific geological conditions of the stope to develop corresponding fire prevention measures, including the reduction of air supply and air leakage in goaf, reduce the amount of coal left, reasonable drainage, nitrogen injection for spontaneous combustion prevention, grouting for spontaneous combustion prevention and permanent closure, fundamentally eliminates the potential for spontaneous combustion during the period of 1116(3) stope end caving. The engineering practice shows that this kind of measure has reference value for the prevention and control of spontaneous combustion during the period of stope end caving.

  14. Optimization long hole blast fragmentation techniques and detonating circuit underground uranium mine stope

    International Nuclear Information System (INIS)

    Li Qin; Yang Lizhi; Song Lixia; Qin De'en; Xue Yongshe; Wang Zhipeng

    2012-01-01

    Aim at high rate of large blast fragmentation, a big difficulty in long hole drilling and blasting underground uranium mine stope, it is pointed out at the same time of taking integrated technical management measures, the key is to optimize the drilling and blasting parameters and insure safety the act of one that primes, adopt 'minimum burden' blasting technique, renew the stope fragmentation process, and use new process of hole bottom indirect initiation fragmentation; optimize the detonating circuit and use safe, reliable and economically rational duplex non-electric detonating circuit. The production practice shows that under the guarantee of strictly controlled construction quality, the application of optimized blast fragmentation technique has enhanced the reliability of safety detonation and preferably solved the problem of high rate of large blast fragments. (authors)

  15. A fuzzy approach to selecting roof supports in longwall mining

    Directory of Open Access Journals (Sweden)

    Yetkin, M. E.

    2016-05-01

    Full Text Available As a decision-making problem, selecting proper machines and equipment plays a key role for mining sites and companies. Many factors affect this decision, and values belonging to these factors can be expressed numerically and/or non-numerically. In order to make the most appropriate decision, engineers must carry out an evaluation process that comprises all criteria that might affect decision-making. To achieve this, multi-criteria decision-making tools are used. As a result of technological developments, coal outputs in longwall mining have risen tremendously over the last decades, and longwall mechanisation has become unavoidable. The significance of powered roof supports in particular increases day- by-day, since the rate of roof support has to be in accordance with the rate of face advance in longwalls. In this study, an integrated fuzzy analytic hierarchy process and fuzzy goal programming model is used to select the most suitable powered roof supports. The procedure is applied to a real-life underground coal mine that is operated using the longwall method. Seven alternative powered roof supports are compared with each other, taking a total of 24 decision criteria under four main topics into account. In conclusion, the most suitable roof supports for the mine under study are determined and recommended to the decision-makers of the system.

  16. Application of combined shrinkage stoping and pillarless sublevel caving mining method to a uranium deposit

    International Nuclear Information System (INIS)

    Fan Changjun

    2012-01-01

    Pillarless sublevel caving mining method was used to mining ores in a uranium mine. Because ore-rock interface changed greatly, this part of ores can not be recovered effectively in the mining process, resulting in the permanent loss of these ores. Aimed at the problem, a combined shrinkage stoping and pillarless sublevel caving mining method is presented. Practices show that the ore recovery is increased, dilution rate is declined, and mining safety is improved greatly by using the combined method. (authors)

  17. Development of subsidence profile functions for longwall mining associated with weak floor strata considering time effects

    International Nuclear Information System (INIS)

    Yu, Z.; Chugh, Y.P.; Yang, G.

    1994-01-01

    Subsidence profile functions for longwall mining in the Illinois Coal Basin were developed for both the headgate and tailgate sides based on field observations of surface subsidence over several longwall panels. One function was applied to predict the subsidence profile for a longwall panel in another Illinois Coal Basin mine, where a good correlation between the predicted and measured results was achieved. Attempts were also made to develop subsidence profile functions including time effect. 4 refs., 9 figs., 1 tab

  18. Subsidence resulting from multiple-seam longwall mining in the western United States

    International Nuclear Information System (INIS)

    Dyni, R.C.

    1991-01-01

    This paper details the investigation of multiple-seam longwall subsidence conducted by the U.S. Bureau of Mines from 1978 to 1989. A field investigation monitored ground surface movements over four upper seam longwall panels and six lower seam panels. The characteristics of the subsidence occurring as a result of mining these panels are examined: in particular, the angle of draw, subsidence development, total magnitude and areal extent, and critical width are evaluated and discussed. comparisons are also made between the characteristics of multiple-seam longwall subsidence and single-seam longwall subsidence that occurred at the same site

  19. How productive are Australia's longwalls?

    Energy Technology Data Exchange (ETDEWEB)

    Baird, G. [McAlpine-B (Australia)

    2002-06-01

    The Australian longwall industry is experiencing record growth in longwall output. But just how productive are Australian mines? One way of finding out is to compare the productivity of Australian mines with that of US mines. A 'US composite' mine (based on 19 mines) was compared with a five-day and a seven-day 'Australian composite' mine (based on 17 mines). In 2000, the US composite produced 4.8 Mt compared to 3.6 Mt and 4.5 Mt for Australian 5-day and 7-day composites respectively. An attempt is made to analyse reasons for these productivity gaps. The author concludes that Australian mines must achieve best practice utilization to match productivity of US mines. One step in achieving this is the successful implementation of techniques such as Total Quality Management (TQM), Reliability Centred Maintenance (RCM), Six Sixma, etc. 3 tabs.

  20. Application of longwall top coal caving to Australian operations

    Energy Technology Data Exchange (ETDEWEB)

    Y. Cai; Bruce Hebblewhite; U. Onder; B. Xu; Mick Kelly; Barry Wright [CSIRO Exploration & Mining (Australia)

    2004-02-15

    The aim of this project was to provide the Australian underground coal mining industry with an up to date, state of the art summary of the Longwall Top Coal Caving (LTCC) mining system and its potential for application in Australia. This project final report addresses the following issues: Update of previously developed Australian thick seam database. Provision of a literature review on the method and a critical evaluation of current published information on both the technology and the operational performance data for the method. The critical issues associated with the method, identified through a risk assessment approach, are highlighted and evaluated in terms of defining the problems and evaluating appropriate elimination or control strategies. The relative economics of an LTCC operation compared to a 4.5m high single pass longwall are developed through an operational and economic model. In terms of equipment innovation, the more recent Chinese developments have relocated the top coal draw points to the rear of the longwall supports. The Chinese equipment has a pivoting supplementary goaf or tail canopy behind the support. Beneath this is a retractable second AFC. With the rear AFC extended and the rear canopy lowered/retracted, caved top coal can be loaded onto the rear AFC, whilst production continues conventionally in front of the supports. In the retracted rear AFC position with the rear canopy raised, the supports and face operation can function conventionally. The Chinese industry reports averages of 15,000 to 20,000 tpd from an LTCC face; up to 75% recovery of 8m+ thick seams using a 3m operating height longwall; and +5 MTPA face production. There are now over 70 LTCC faces in China. A new semi-automated 300m long LTCC face installed at the Xinglongzhuang Colliery. This is heading towards producing 7 MTPA in 2002/2003.

  1. Experimental study on foam coverage on simulated longwall roof

    Science.gov (United States)

    Reed, W.R.; Zheng, Y.; Klima, S.; Shahan, M.R.; Beck, T.W.

    2018-01-01

    Testing was conducted to determine the ability of foam to maintain roof coverage in a simulated longwall mining environment. Approximately 27 percent of respirable coal mine dust can be attributed to longwall shield movement, and developing controls for this dust source has been difficult. The application of foam is a possible dust control method for this source. Laboratory testing of two foam agents was conducted to determine the ability of the foam to adhere to a simulated longwall face roof surface. Two different foam generation methods were used: compressed air and blower air. Using a new imaging technology, image processing and analysis utilizing ImageJ software produced quantifiable results of foam roof coverage. For compressed air foam in 3.3 m/s (650 fpm) ventilation, 98 percent of agent A was intact while 95 percent of agent B was intact on the roof at three minutes after application. At 30 minutes after application, 94 percent of agent A was intact while only 20 percent of agent B remained. For blower air in 3.3 m/s (650 fpm) ventilation, the results were dependent upon nozzle type. Three different nozzles were tested. At 30 min after application, 74 to 92 percent of foam agent A remained, while 3 to 50 percent of foam agent B remained. Compressed air foam seems to remain intact for longer durations and is easier to apply than blower air foam. However, more water drained from the foam when using compressed air foam, which demonstrates that blower air foam retains more water at the roof surface. Agent A seemed to be the better performer as far as roof application is concerned. This testing demonstrates that roof application of foam is feasible and is able to withstand a typical face ventilation velocity, establishing this technique’s potential for longwall shield dust control. PMID:29563765

  2. Development of a high capacity longwall conveyor. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Sparks, C

    1982-05-01

    The objectives of this program were to develop, fabricate, and demonstrate a longwall conveying system capable of transporting coal at a rate of 9000 tons/day (1000 tons/hr) and capable of accommodating a surge rate of 20 tons/min. The equipment was required to have the structural durability to perform with an operating availability of 90%. A review of available literature and discussions with longwall operators identified the problem areas of conveyor design that required attention. The conveyor under this contract was designed and fabricated with special attention given to these areas, and also to be easily maintainable. The design utilized twin 300 hp drives and twin inboard 26-mm chain at 270 ft/min; predictions of capacity and reliability based on the design indicating that it would satisfy the program requirements. Conveyor components were critically tested and the complete conveyor was surface-tested, the results verifying the design specifications. In addition, an instrumentation system was developed with analysis by computer techniques to monitor the performance of the conveyor. The conveyor was installed at a selected mine site, and it was the intention to monitor its performance over the entire longwall panel. Monitoring of the conveyor performance was conducted over approximately one-third of the longwall panel, at which point further effort was suspended. However, during the monitored period, data collected from various sources showed the conveyor to have exhibited its capability of transporting coal at the desired rate, and also to have conformed to the program requirements of reliability and availability.

  3. Stress Ratios in Entire Mine Stopes with Cohesionless Backfill: A Numerical Study

    Directory of Open Access Journals (Sweden)

    Pengyu Yang

    2017-10-01

    Full Text Available Evaluation of stress states in backfilled mine stopes (or similar openings, using arching theory, can be largely impacted by the value selected for the earth pressure coefficient, K = σ′h/σ′v. Recently, the current study’s authors addressed the debate about the value of K near the opening center, based on Rankine’s active coefficient (Ka and at-rest coefficient (K0. Here, stress ratios in vertical backfilled stopes are numerically assessed (in two dimension, 2D, considering both the independent and related backfill internal friction angle (ϕ′ and Poisson’s ratio (ν. Emphasis is placed on the backfill state near stope walls, where local rotation of stresses occurs, so the coefficient (K and principal stress ratio, Kps (= σ′3/σ′1, should be distinguished. Parametric analyses indicate that values of K and Kps depend on the position and the relationship between ϕ′ and ν. Near the opening center, K (= Kps is close to Ka when ν or ϕ′ is below a critical value; otherwise the value approaches K0, defined from ν. Near both walls, Kps is always close to Ka, while K is near K0 for related ν − ϕ′ cases and depends on their respective values for independent ν and ϕ′. Additional simulations conducted with interface elements indicate that the stress ratios near the opening center line are insensitive to interface roughness and are almost identical to values obtained without interfaces, but the stress ratios near walls may change for less rough or smooth interfaces.

  4. Longwall Mining Stability in Take-Off Phase

    Directory of Open Access Journals (Sweden)

    María-Belén Prendes-Gero

    2013-01-01

    Full Text Available Mechanised longwall mining is one of the more commonly employed exploitation methods in underground mines in the north of Spain as well as in the rest of the world. It is continuously changing and evolving, with new techniques, technology, equipment, and face management practices and systems appearing for the purposes of improving aspects such as operational and financial performances and, above all, the safety of the miners. Despite its importance, there are no regulations for the mining of longwall coal seams. This work aims to contribute to an advance in the design and optimisation of the roof support in longwall mining, analysing the stability of the roof using a method based on the resistance of materials, which considers the characteristics of the properties of the roof materials. The influence of not only the individual elements of support but also the coalface, which is considered one more supporting element, is investigated. The longitudinal and transverse spacings of the support and the number of walkways constituting the exploitation panel are analysed. The proposed formulation is validated by information gathered in a mine located in the region of Castilla-Leon.

  5. Influence of Blasted Uranium Ore Heap on Radon Concentration in Confined Workspaces of Shrinkage Mining Stope

    Science.gov (United States)

    Ye, Y. J.; Liang, T.; Ding, D. X.; Lei, B.; Su, H.; Zhang, Y. F.

    2017-07-01

    A calculation model for radon concentration in shrinkage mining stopes under various ventilation conditions was established in this study. The model accounts for the influence of permeability and area of the blasted ore heap, ventilation air quantity, and airflow direction on radon concentration in a confined workspace; these factors work together to allow the engineer to optimize the ventilation design. The feasibility and effectiveness of the model was verified by applying it to mines with elevated radon radiation exposure. The model was found to accurately changes in radon concentration according to the array of influence factors in underground uranium mines.

  6. 30 CFR 18.53 - High-voltage longwall mining systems.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage longwall mining systems. 18.53..., EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Construction and Design Requirements § 18.53 High-voltage longwall mining systems. (a) In each high-voltage motor...

  7. Analysis of Availability of Longwall-Shearer Based On Its Working Cycle

    Science.gov (United States)

    Brodny, Jaroslaw; Tutak, Magdalena

    2017-12-01

    Effective use of any type of devices, particularly machines has very significant meaning for mining enterprises. High costs of their purchase and tenancy cause that these enterprises tend to the best use of own technical potential. However, characteristics of mining production causes that this process not always proceeds without interferences. Practical experiences show that determination of objective measure of utilization of machine in mining company is not simple. In the paper methodology allowing to solve this problem is presented. Longwall-shearer, as the most important machine between longwall mechanical complex. Also it was assumed that the most significant meaning for determination of effectiveness of longwall-shearer has its availability, i.e. its effective time of work related to standard time. Such an approach is conforming to OEE model. However, specification of mining branch causes that determined availability do not give actual state of longwall-shearer’s operation. Therefore, this availability was related to the operation cycle of longwall-shearer. In presented example a longwall-shearer works in unidirectional cycle of mining. It causes that in one direction longwall-shearer mines, moving with operating velocity, and in other direction it does not mine and moves with manoeuvre velocity. Such defined working cycle became a base for determinate availability of longwall-shearer. Using indications of industrial automatic system for each of working shift there were determined number of cycles of longwall-shearer and availability of each one. Accepted of such way of determination of availability of longwall-shearer enabled to perform accurate analysis of losses of its availability. These losses result from non-planned shutdowns of longwall-shearer. Thanks to performed analysis based on the operating cycle of longwall-shearer time of its standstill for particular phase of cycle were determined. Presented methodology of determination of longwall

  8. A study of the relationship between saturated zone response and longwall mining-induced ground strain

    International Nuclear Information System (INIS)

    Trevits, M.A.; Matetic, R.J.

    1992-01-01

    The effects of longwall mining operations on near-surface water are not well understood. The sparse information that is available indicates a correlation between the proximity of the approaching longwall face and fluctuations in observation water wells. Furthermore, the magnitude of mining-induced subsidence appears to coincide with the degree of water level fluctuation. To provide additional information about these effects, the US Bureau of Mines has been installing well arrays over select longwall operations and observing the change as mining progresses through the area. Studies have been conducted at mine sites located in Pennsylvania and Ohio. The results of the research suggest that a relationship exists between water level fluctuations and the ground strain developed by the approaching longwall face. This paper explores research conducted at three mine sites and explains both the magnitude and timing of the observed water level fluctuations as a function of longwall mining-induced ground movement

  9. Sub level open stoping mining method for the Remaja type deposits, Kalan, West Kalimantan, Indonesia

    International Nuclear Information System (INIS)

    Sumaryanto, A.

    2014-01-01

    and compared respectively as part of Vertical Crater Retreat and Sub Level Stoping mining methods. Actually the latter method is not strictly Sub Level Stoping, because in order to minimize the risk of collapse of the hanging wall, which dips at 65°, the major part of the depleted stope is back filled with the waste and could be called Sub Level Open Stoping. This method has been considered as the more convenient but might be do more for the feasibility study, and slightly modified it in order to make the loading of the broken ore at the bottom of the stope easier and allow earlier back filling in order to increase the hanging wall stability. (author)

  10. Improved understanding of the use of short tendons for stope support under rockfall and rockburst conditions, (Phase I).

    CSIR Research Space (South Africa)

    Roberts, DP

    2002-03-01

    Full Text Available The aim of this project was to determine whether the introduction of short bolts into a stope hangingwall would increase the stability of the hangingwall beam. A simple physical 1/10th hangingwall model was constructed out of concrete...

  11. Genesis and geomorphic evolution of the Velké pinky stopes in the Zlatohorská Highlands, Eastern Sudetes

    Science.gov (United States)

    Lenart, Jan; Tichavský, Radek; Večeřa, Josef; Kapustová, Veronika; Šilhán, Karel

    2017-11-01

    Montanogenic landforms are commonly viewed as hazards by society, but they are also holders of specific and uncommon morphology with unique dynamics that act as remarks on landscape history. The Velké pinky stopes in the Zlatohorská Highlands, Eastern Sudetes, are naturally revitalized post-mining landforms with long-term geoecological succession. Their genetic origin is diverse but recent processes, such as deep-seated slope deformations, rockfalls and ground subsidence, have resulted in a distinct morphology dominated by rock walls and the accumulation of blocks and debris wedges. This morphology predisposes the stopes to become the core area of the most recent dynamic geomorphic activity within the wider, relatively homogenous area. By dendrogeomorphic techniques, we identified more than 20 rockfall events within three of the stopes with increased activity since the 1980s. Only the 1991 and 2006 events were identical for all three stopes. We obtained the years of exposures from 10 roots, revealing the ground subsidence and opening of tension cracks or even the lateral retreat of the flanks of minor depressions. The Schmidt hammer test revealed the most recent and fresh gravitational activity in one of the stopes. A relationship between the superficial morphology and underground structure was proven by electrical resistivity profiling. Compared to the previous studies engaged with the abandoned mines, we presented how complex their evolution can be. Our study brings new information about the historical development of anthropogenic relief forms. Moreover, our results suggest that standard research approaches can be successfully applied for development analysis of these specific forms.

  12. Hydrogeologic impacts of underground (Longwall) mining in the Illinois basin

    International Nuclear Information System (INIS)

    Booth, C.J.

    1992-01-01

    This paper reports that hydrogeological impacts of active longwall mining were studied at two sites in Illinois. At the site with the more transmissive sandstone aquifer, aquifer permeabilities increased an order of magnitude due to subsidence. Piezometric levels declined with subsidence due to increased porosity, and ahead of mining due to a transmitted drawdown. Levels recovered rapidly at first and fully over two years. At the site with the less transmissive aquifer, impacts were similar except that recovery has been limited. Local aquifer enhancement through increased yield can occur, but only where the aquifer is transmissive enough for recovery

  13. Analysis and Assessment of Parameters Shaping Methane Hazard in Longwall Areas

    Directory of Open Access Journals (Sweden)

    Eugeniusz Krause

    2013-01-01

    Full Text Available Increasing coal production concentration and mining in coal seams of high methane content contribute to its growing emission to longwall areas. In this paper, analysis of survey data concerning the assessment of parameters that influence the level of methane hazard in mining areas is presented. The survey was conducted with experts on ventilation and methane hazard in coal mines. The parameters which influence methane hazard in longwall areas were assigned specific weights (numerical values. The summary will show which of the assessed parameters have a strong, or weak, influence on methane hazard in longwall areas close to coal seams of high methane content.

  14. Electromechanical dynamic analysis for the drum driving system of the long-wall shearer

    Directory of Open Access Journals (Sweden)

    Changzhao Liu

    2015-10-01

    Full Text Available The drum driving system is one of the weakest parts of the long-wall shearer, and some methods are also needed to monitor and control the long-wall shearer to adapt to the important trend of unmanned operation in future mining systems. Therefore, it is essential to conduct an electromechanical dynamic analysis for the drum driving system of the long-wall shearer. First, a torsional dynamic model of planetary gears is proposed which is convenient to be connected to the electric motor model for electromechanical dynamic analysis. Next, an electromechanical dynamic model for the drum driving system is constructed including the electric motor, the gear transmission system, and the drum. Then, the electromechanical dynamic characteristics are simulated when the shock loads are acted on the drum driving system. Finally, some advices are proposed for improving the reliability, monitoring the operating state, and choosing the control signals of the long-wall shearer based on the simulation.

  15. Development of an illumination system for longwall coal mines. Report for 1973--1975

    Energy Technology Data Exchange (ETDEWEB)

    Friedline, G.; Gartley, M.; Ketler, A.; Pellmann, R.

    1975-11-06

    The report describes the development of a lighting system beginning with a prototype longwall mockup followed by the design, fabrication, and testing of the system in an operating coal mine. Details of the design, installation, operation, and performance are given. The results have provided the basic technology needed to illuminate longwall sections. The existence of the technology is part of the prerequisite to promulgation of illumination standards as required by the Coal Mine Health and Safety Act of 1969. (GRA)

  16. Methodological details of determining maximum single concentration of dust along scraper longwalls of coal mines

    Energy Technology Data Exchange (ETDEWEB)

    Rubanov, G.P.; Grebtsov, E.M.; Kurnosov, V.K.; Tolstoi, G.I.

    1988-06-01

    Recommendations of 'Instructions on determining pneumoconiosis danger of mine work in coal mines' for choice of a basic point for measuring maximum single concentration of dust along scraper longwalls do not make it possible to objectively evaluate dust load at working places. In the Instructions, a point at 10 to 15 m from exit of longwall on the ventilation drift with an emergent stream of air is proposed for the dust probe. This designated point does not take into account the influence of the scheme of ventilation of the walls on formation of dust currents. Investigations of probes taken at different places along the longwall (at the beginning, 15 m from the begining, 15 m from the end, at the niche and transfer point of the longwal) using direct and reverse flow schemes of ventilation showed that the best point for determining maximum single concentratin of dust is a point in the middle of the longwall where dust currents are the same for both systems of ventilation, and use of a new method of calculating the dust load by testing at many different positions along the scraper longall makes it possible to determine the category of pneumonoconiosis danger for workers at scraper longwalls.

  17. Does longwall mining have a detrimental effect on shallow ground water sources?

    International Nuclear Information System (INIS)

    Matetic, R.J.; Trevits, M.A.

    1992-01-01

    Longwall mining typically affects the entire overburden rock mass from the unit immediately above the coalbed being mined to the ground surface. It is natural to assume that any water-bearing zones contained within this interval may be influenced to some degree. In some cases, a complete loss of water may be experienced and in others an increase in the hydrologic properties may occur. To address this apparent dichotomy, the US Bureau of Mines is conducting a comprehensive program of subsidence research in select mining areas of the United States. One such site was located in Vinton County, Ohio where two contiguous longwall panels were designated as a study area. The two longwall panels measured approximately 900 ft wide and 9,000 ft long. The thickness of the extracted coal was about 55 inches. The longwall panels were separated by five entries or approximately 350 ft. Overburden thickness in the study area varied from 200 to 350 ft. To evaluate the effects of mining, seven, 8 5/8-inch diameter observation wells were drilled at critical positions above the longwall panels. Water level fluctuations, surface subsidence and hydrologic properties were measured as mining progressed through the study area. Results of this study show mining of both longwall panels did not interrupt the hydrologic regime. This paper provides a detailed case study delineating the timing and effects of mining on local shallow ground water sources

  18. Survey and assessment of support for non-standard (anomalous) stope areas in the gold and platinum industry.

    CSIR Research Space (South Africa)

    Leach, AR

    2002-12-01

    Full Text Available those due to stress and stress damage and possibly increased rock deformation, geological conditions, mining considerations, and human factors. This permits a clearer identification of specific hazards and to highlight the consequences and severity....1 Classification of stress intensity Table 6.2 Definitions of standard stopes Table 6.3 Definitions of non-standard conditions categorised by stress, geological, mining practice and human factors Table 6.4 Key roles to aid in mine planning and operations Table...

  19. A new cavability assessment criterion for longwall top coal caving

    Energy Technology Data Exchange (ETDEWEB)

    Vakili, A.; Hebblewhite, B.K. [University of New South Wales, Sydney, NSW (Australia)

    2010-12-15

    This paper describes the main results of project aimed at developing a new cavability assessment criterion for top-coal, and improving the overall understanding of the caving mechanism in Longwall Top Coal Caving (LTCC) technology. The research methodology for this study incorporated a combination of analytical, observational and empirical engineering methods. The two major outcomes of the study were an improved understanding of the caving mechanics, and a new cavability assessment system, the Top-Coal Cavability Rating (TCCR). New conceptual models were introduced for better understanding of top coal caving mechanism. The results of the conceptual investigations suggest that six major parameters can influence the cavability of a typical coal seam, i.e. deformation modulus; vertical pre-mining stress; 3-sub-horizontal pre-mining stress; 4-seam thickness; spacing of sub-horizontal joints; and spacing of sub-vertical joints. The applicability of TCCR system was investigated by back analysing the cavability in earlier LTCC practices.

  20. Surface movement above an underground coal longwall mine after closure

    Science.gov (United States)

    Vervoort, André

    2016-09-01

    The surface movement in an area of about 22 km2 above the underground coal mine of Houthalen was analyzed based on Interferometry with Synthetic Aperture Radar (InSAR) measurements. After its closure in 1992, a residual subsidence was observed over a period of several years, followed by an uplift of the surface above and around the past longwall panels, whereby the rate of movement was, in absolute terms, of the same order for the two types of movements. The processes behind these movements are different. The process of subsidence is caused by the caving of the roof above the mined-out area and is mainly a mechanical stress-deformation process, including time-dependent aspects. However, the process of uplift is most probably caused by the swelling of the clay minerals in the argillaceous rocks in the coal strata after the flooding of the underground workings. Hence, the areas in which there is the greatest risk of damage to the surface infrastructure are not the same for the hazards linked to subsidence and uplift. For example, the zone in which the maximum uplift occurs clearly is at a different location from that of the zone with the maximum residual subsidence. There is no clear sign that the amount of mining underneath affects the residual subsidence, and there is no indication that the process of uplift is linked directly to the mining characteristics. It is more likely that uplift as the result of flooding is initiated at, or close to, the vertical shafts.

  1. Mechanised apparatus comprising two ploughs for cutting ore in a stope. Dispositif mecanise comportant deux rabots pour l'abbatage de mineral dans une taille

    Energy Technology Data Exchange (ETDEWEB)

    David, H.

    1988-05-25

    A mechanised apparatus for cutting ore in a stope comprising at least one walking support chock, a service conveyor, a first plough associated with said conveyor and a second plough characterised in that it further comprises an assembly of elements forming a metal plate disposed between the base member and the cap of the chock at the front of said apparatus, over the entire length of the stope, said second plough being disposed at the front of said plate and each of the plates forming the metal plate being connected to the base member which corresponds thereto by means of at least one jack.

  2. Numerical Simulation of Aerogasdynamics Processes in A Longwall Panel for Estimation of Spontaneous Combustion Hazards

    Science.gov (United States)

    Meshkov, Sergey; Sidorenko, Andrey

    2017-11-01

    The relevance of a solution of the problem of endogenous fire safety in seams liable to self-ignition is shown. The possibilities of numerical methods of researches of gasdynamic processes are considered. The analysis of methodical approaches with the purpose to create models and carry out numerical researches of aerogasdynamic processes in longwall panels of gas mines is made. Parameters of the gob for longwall mining are considered. The significant influence of geological and mining conditions of conducting mining operations on distribution of air streams on longwall panels and effective management of gas emission is shown. The aerogasdynamic model of longwall panels for further research of influence of parameters of ventilation and properties of gob is presented. The results of numerical researches including distribution of air streams, fields of concentration of methane and oxygen at application of various schemes of airing for conditions of perspective mines of the Pechora basin and Kuzbass are given. Recommendations for increase of efficiency of the coal seams mining liable to selfignition are made. The directions of further researches are defined.

  3. Analysis of Influence of Goaf Sealing from Tailgate On the Methane Concentration at the Outlet from the Longwall

    Science.gov (United States)

    Tutak, Magdalena; Brodny, Jaroslaw

    2017-12-01

    One of the most common and most dangerous gas hazards in underground coal mine is methane hazard. Formation of dangerous, explosive concentrations of methane occurs the most often in the region of crossing of longwall with the ventilation gallery. Particularly it applies to longwalls ventilated in „U from bounds” system. Outflow of gases from the goaf to the tailgate takes place through the boundary surfaces of this sidewalk with goaf. Main cause of this process is a phenomenon of air filtration through the goaf with caving. This filtration is a result of migration of the part of ventilation air stream supplied to the longwall. This air is released into the goaf on the entire longwall length; however, its greater amount gets to the goaf with caving space at the crossing of maingate with exploitation longwall. Albeit, the biggest outflow of air mixture and gases from the goaf occurs in top gate in upper corner of the longwall. This is a result of pressure difference in this region. This phenomenon causes that to the space of heading besides the air also other gases present in the goaf, mainly methane, are released. Methane is an explosive gas. Most often boundaries of explosive mixtures of methane, air and inert gases are described by the so-called Coward triangle explosion. Within the limits of the occurrence of the concentration of explosive methane explosion initials may be endogenous fire, blasting or sparks arising from friction of moving lumps of rock. Therefore, in order to decrease its concertation in this region, by limiting its outflow from the goaf with caving different actions are taken. One of such action is sealing of goaf from top gate side. Analysis of impact of sealing of these goaf on the methane concentration at the outlet of longwall is main aim of studies researches. Model of tested region, together with boundary conditions (including parameters of flowing air and the methane content) was developed on the base of real data from one of the

  4. Surface structural damage associated with longwall mining near Tuscaloosa, Alabama: a case history

    International Nuclear Information System (INIS)

    Isphording, W.C.

    1992-01-01

    Initially the paper examines the frequency of coal mine subsidence and the influence on surface subsidence of subsurface mining methods, i.e. room and pillar and longwall mining. A case study of the subsidence damage caused to a log house near Tuscaloosa, Alabama (USA), when a longwall panel passed beneath it is presented. The damage resulted in the homeowners suing the mining company for negligence. The article discusses information provided to the plaintiffs attorneys by the author. Aspects covered are: the subsidence and damage to the property; prediction of subsidence; the monitoring of subsidence; and the prevention of subsidence. An out-of-court settlement was agreed by the two parties. 15 refs., 5 figs

  5. Simulation of longwall top coal caving sequence and coal clearance system

    Energy Technology Data Exchange (ETDEWEB)

    Xu, B.; Hebblewhite, B.; Cai, Y. [University of New South Wales, Sydney, NSW (Australia). School of Mining Engineering

    2003-07-01

    The Longwall Top Coal Caving (LTCC) system of mining thick coal seams offers productivity and safety benefits, compared to the single pass operations used in Australia. The application of simulation modelling (AutoMod) to optimize caving sequences, predict throughput of a LTCC system, find and minimize slow-downs, and predict peak loading capacity of each conveyor section is described. Data sampled from an operating LTCC face in China is used to verify the model. 9 refs., 11 figs., 1 tab.

  6. An Innovative Approach for Gob-Side Entry Retaining in Thick Coal Seam Longwall Mining

    OpenAIRE

    Manchao He; Yubing Gao; Jun Yang; Weili Gong

    2017-01-01

    Gob-side entry retaining (GER) is a popular non-pillar mining technique regarding how to reserve a gateroad for the use of next panel mining. When used in thick coal seams, the conventional entry retaining method requires a huge amount of filling materials and may cause entry (gateroad) accidents. Thus, an innovative non-pillar longwall mining approach is introduced. First, structural and mechanical models were built to explore the mechanism of the new approach. The modeling results indicate ...

  7. Modeling the effects of longwall mining on the ground water system

    International Nuclear Information System (INIS)

    Matetic, R.J.; Liu, J.; Elsworth, D.

    1995-01-01

    The objective of this US Bureau of Mines hydrologic-subsidence investigation was to evaluate the effects of longwall mining on the local ground water regime through field monitoring and numerical modeling. Field data were obtained from multiple-position borehole extensometers (MPBXs) that were used to measure subsurface displacements. Survey monuments were installed to measure mining-induced surface deformations. Numerous drawdown and recovery tests were performed to characterized hydrologic properties of the overburden strata. Coreholes were drilled above the study area to determine lithologic and strength characteristics of the overburden strata using the rock samples collected. Electronic recorders were installed on all monitoring wells to continuously monitor ground water levels in coordination with mining of the longwall panels. A combined finite element model of the deformation of overlying strata, and its influence on ground water flow was used to define the change in local and regional water budgets. The predicted effects of the postmining ground water system determined by the model correlated well with field data collected from the fieldsite. Without an infiltration rate added to the model, a static decrease of 3.0 m (10 ft) in water level would occur due to mining of both longwall panels and if an infiltration rate was inputted in the model, no predicted long-term effects would occur to the ground water system

  8. Foam property tests to evaluate the potential for longwall shield dust control.

    Science.gov (United States)

    Reed, W R; Beck, T W; Zheng, Y; Klima, S; Driscoll, J

    2018-01-01

    Tests were conducted to determine properties of four foam agents for their potential use in longwall mining dust control. Foam has been tried in underground mining in the past for dust control and is currently being reconsidered for use in underground coal longwall operations in order to help those operations comply with the Mine Safety and Health Administration's lower coal mine respirable dust standard of 1.5 mg/m 3 . Foams were generated using two different methods. One method used compressed air and water pressure to generate foam, while the other method used low-pressure air generated by a blower and water pressure using a foam generator developed by the U.S. National Institute for Occupational Safety and Health. Foam property tests, consisting of a foam expansion ratio test and a water drainage test, were conducted to classify foams. Compressed-air-generated foams tended to have low expansion ratios, from 10 to 19, with high water drainage. Blower-air-generated foams had higher foam expansion ratios, from 30 to 60, with lower water drainage. Foams produced within these ranges of expansion ratios are stable and potentially suitable for dust control. The test results eliminated two foam agents for future testing because they had poor expansion ratios. The remaining two foam agents seem to have properties adequate for dust control. These material property tests can be used to classify foams for their potential use in longwall mining dust control.

  9. Modeling the effect of seal leakage on spontaneous heating in a longwall gob area

    Energy Technology Data Exchange (ETDEWEB)

    Smith, A.C.; Yuan, L. [National Inst. for Occupational Safety and Health, Pittsburgh, PA (United States). Office of Mine Safety and Health Research

    2010-07-01

    Three coal mines in the United States with a history of spontaneous combustion use a bleederless ventilation system as a control measure. In a bleederless system, one of the headgate entries is used as the tailgate entry of the succeeding panel and is isolated from the gob of the active panel by gob seals that are installed in the headgate entry as the face advances. An active longwall panel using a Y-type bleederless ventilation system was simulated in this study. As longwall mining progresses, some seals are known to leak. Computational fluid dynamics (CFD) simulations were performed to study the effect of seal leakage on spontaneous heating of coal in the longwall gob area. The simulation results showed that under typical bleederless ventilation conditions, the maximum temperature in the gob increased with an increase in leakage rate. The maximum temperature occurred at the headgate side corner at the back end of the panel. When only 1 or 2 seals were leaking, the maximum temperature occurred around the seal. The results demonstrate that complex interactions between pressure differential and gob permeability at different locations in the gob cause ventilation pathways. The interactions depend greatly on gob permeability and seal leakage rates. 8 refs., 1 tab., 14 figs.

  10. Estimation of the Change in Storage Capacity above Mined Longwall Panels.

    Science.gov (United States)

    Tammetta, Paul

    2016-09-01

    Accurate estimation of the change in groundwater storage capacity (S) above mined longwall panels is vital for analysis of postmining void water level recovery in coal mines, and assessment of water quality impacts. At present, there is no generalized representation of the spatial distribution of changes in S around a panel. Current estimates are generally bulk averages with high uncertainty, precluding calculation of groundwater velocities in various parts of the subsurface. In this work, a recently published hydrogeological conceptual model of longwall caving is used in conjunction with observations from borehole extensometers, goaf height measurements, and pumping/drawdown records for mine pools to develop a subsurface spatial distribution of changes in S following longwall caving, with reduced uncertainty in their magnitudes. The assumption of saturation in the disturbed zone proved critical for obtaining accurate results and in reconciling widely varying published estimates of S. Results indicate that the goaf and collapsed zones each absorb over 30% of the mined volume, and about 20% is absorbed by the surface subsidence trough. The increase in S in the collapsed zone is inversely proportional to the amount of surface subsidence. The conceptual model is updated with these results to present the spatial distribution of S after caving. The results allow calculation of water velocities in various zones, and may provide greater accuracy in estimation of water level rebound and water quality processes. Most of the S participating in groundwater flows is provided by defects rather than the matrix. © 2016, National Ground Water Association.

  11. Voussoir beam model for lower strong roof strata movement in longwall mining – Case study

    Directory of Open Access Journals (Sweden)

    Chuang Liu

    2017-12-01

    Full Text Available The paper presents the influence of varying immediate roof thickness on the lower strong roof strata movement and failure pattern in longwall coal mining with large mining height. The investigation is based on 58 geological drill holes and hydraulic shield pressure measurements around the longwall Panel 42105 of the Buertai Mine in Inner Mongolia Autonomous Region, China. The longwall Panel 42105 is characterized by relatively soft immediate roof strata of varying thickness superposed by strong strata, herein defined as lower strong roof. A voussoir beam model is adopted to interpret the structural movement of the lower strong roof strata and shield pressure measurements. It is shown that when the immediate roof is relatively thick, the broken overlying lower strong roof tends to form a stable voussoir beam with previously broken layer, thus not exerting high pressure on the hydraulic shield and working face. When the immediate roof is relatively thin, the broken overlying lower strong roof tends to behave as a cantilever beam, thus exerting higher pressure on the hydraulic shield and working face. Comparison of model predictions with measured time-weighted average shield pressure (TWAP shows good agreement.

  12. Characterization of airborne float coal dust emitted during continuous mining, longwall mining and belt transport.

    Science.gov (United States)

    Shahan, M R; Seaman, C E; Beck, T W; Colinet, J F; Mischler, S E

    2017-09-01

    Float coal dust is produced by various mining methods, carried by ventilating air and deposited on the floor, roof and ribs of mine airways. If deposited, float dust is re-entrained during a methane explosion. Without sufficient inert rock dust quantities, this float coal dust can propagate an explosion throughout mining entries. Consequently, controlling float coal dust is of critical interest to mining operations. Rock dusting, which is the adding of inert material to airway surfaces, is the main control technique currently used by the coal mining industry to reduce the float coal dust explosion hazard. To assist the industry in reducing this hazard, the Pittsburgh Mining Research Division of the U.S. National Institute for Occupational Safety and Health initiated a project to investigate methods and technologies to reduce float coal dust in underground coal mines through prevention, capture and suppression prior to deposition. Field characterization studies were performed to determine quantitatively the sources, types and amounts of dust produced during various coal mining processes. The operations chosen for study were a continuous miner section, a longwall section and a coal-handling facility. For each of these operations, the primary dust sources were confirmed to be the continuous mining machine, longwall shearer and conveyor belt transfer points, respectively. Respirable and total airborne float dust samples were collected and analyzed for each operation, and the ratio of total airborne float coal dust to respirable dust was calculated. During the continuous mining process, the ratio of total airborne float coal dust to respirable dust ranged from 10.3 to 13.8. The ratios measured on the longwall face were between 18.5 and 21.5. The total airborne float coal dust to respirable dust ratio observed during belt transport ranged between 7.5 and 21.8.

  13. An Innovative Approach for Gob-Side Entry Retaining in Thick Coal Seam Longwall Mining

    Directory of Open Access Journals (Sweden)

    Manchao He

    2017-11-01

    Full Text Available Gob-side entry retaining (GER is a popular non-pillar mining technique regarding how to reserve a gateroad for the use of next panel mining. When used in thick coal seams, the conventional entry retaining method requires a huge amount of filling materials and may cause entry (gateroad accidents. Thus, an innovative non-pillar longwall mining approach is introduced. First, structural and mechanical models were built to explore the mechanism of the new approach. The modeling results indicate that effective bulking of the gob roof and reasonable support of the entry roof were key governing factors in improving entry stabilities and reducing roof deformations. Accordingly, a directional roof fracturing technique was proposed to contribute to gob roof caving, and a constant resistance and large deformation anchor (CRLDA cable was used to stabilize the entry roof. Subsequently, the evolutionary laws of the roof structure and stresses were explored using numerical simulation. It was found that the structure of the surrounding rocks around the retained entry changed significantly after roof fracturing. The stress-bearing center was transferred to the gob area, and the entry roof was in a low stress environment after adopting the approach. Finally, the approach was tested on a thick coal seam longwall mining panel. Field monitoring indicates that the retained entry was in a stable state and the index of the retained entry met the requirement of the next mining panel. This work provides an effective and economical approach to non-pillar longwall mining in thick coal seams.

  14. Reducing dust at longwall shearers by confining the dust cloud to the face

    Energy Technology Data Exchange (ETDEWEB)

    Kissell, F.; Jayaraman, N.; Taylor, C.; Jankowski, R.

    1981-02-01

    The Bureau of Mines has developed the shearer-clearer dust control system for longwall shearers. The system partitions the airflow around the shearer into a clean split and a contaminated split. The dust cloud is confined to the vicinity of the coal face, while the shearer operators remain in the clean split on the gob side of the machine. The shearer-clearer operates on the principle that each water spray moves air like a small fan and can be positioned to direct the dustry air toward the face. The hardware is inexpensive and can be installed in a single shift. It consists of several strategically mounted water sprays and one or more passive barriers. Laboratory testing indicates reductions in shearer operator dust exposure as high as 97%. Preliminary results indicate that considerable dust reductions at the shearer may also be obtained. In conjunction with the development of the shearer-clearer, dust surveys were conducted in three other mines to determine if some shearer spray systems currently in use partition the flow in a manner similar to the shearer-clearer, and if so, whether this partially accounts for markedly cleaner conditions on some longwalls. Results indicate this to be the case: a feature of the cleaner longwalls was a downwind orientation of their water sprays, which is a key element of the shearer-clearer system. The shearer-clearer system described was designed for an Eickhoff EDW 300 shearer working a 7-foot coal seam. Testing to date has concentrated on cutting directions counter to the primary airflow. It is expected that different systems will be required to accommodate the range of conditions occurring underground. Application to conditions different than those described is not likely to produce the same results.

  15. Effect of the distance between disruptive disturbances on the output of powered longwall equipment sets

    Energy Technology Data Exchange (ETDEWEB)

    Kozel, K.K.; Seredyuk, V.L. (L' vovsko-Volynskaya GRE (USSR))

    1991-09-01

    Presents a statistical analysis of data on tectonic disturbances in the L'vovsk-Volynsk black coal basin and their effect on productivity. The effect of disjunctive disturbances on working face advance rate was analyzed on the basis of data on disturbances with stratigraphic amplitudes of 0.9{+-}0.21 m. Dependence of the coefficient of maintained production level on the distance between disjunctive disturbances is shown in graphs for the 1K-101 and GSh-68 longwall equipment sets. Recommendations are made for increasing the advance rate when crossing tectonic disturbances.

  16. Establishing and Scaling-Up Clinical Social Franchise Networks: Lessons Learned From Marie Stopes International and Population Services International

    Science.gov (United States)

    Thurston, Sarah; Chakraborty, Nirali M; Hayes, Brendan; Mackay, Anna; Moon, Pierre

    2015-01-01

    In many low- and middle-income countries, a majority of people seek health care from the private sector. However, fragmentation, poor economies of scale, inadequate financing, political opposition, a bias toward curative services, and weak regulatory and quality control systems pose serious challenges for the private sector. Social franchising addresses a number of these challenges by organizing small, independent health care businesses into quality-assured networks. Global franchisors Marie Stopes International (MSI) and Population Services International (PSI) have rapidly scaled their family planning social franchising programs in recent years, jointly delivering over 10.8 million couple-years of protection (CYPs) in 2014—up 26% from 8.6 million CYPs just 1 year prior. Drawing on experience across MSI’s 17 and PSI’s 25 social franchise networks across Africa, Asia, and Latin America and the Caribbean, this article documents the organizations’ operational approaches, challenges faced, and solutions implemented. The organizations provide intensive capacity building and support for private-sector providers, including clinical training, branding, monitoring quality of franchised services, and commodity support. In addition, franchising programs engage providers and clients through behavior change communication (BCC) and demand generation activities to raise awareness and to attract clients, and they implement initiatives to ensure services are affordable for the lowest-income clients. Social franchise programs offer the private sector a collective platform to better engage government in health policy advocacy and for integrating into new public health care financing and procurement mechanisms. The future of social franchising will require developing approaches to scale-up and sustain the model cost-effectively, selectively integrating other health services into the franchise package, and being responsive to evolving health care financing approaches with the

  17. Increasing Access to Family Planning Choices Through Public-Sector Social Franchising: The Experience of Marie Stopes International in Mali.

    Science.gov (United States)

    Gold, Judy; Burke, Eva; Cissé, Boubacar; Mackay, Anna; Eva, Gillian; Hayes, Brendan

    2017-06-27

    Mali has one of the world's lowest contraceptive use rates and a high rate of unmet need for family planning. In order to increase access to and choice of quality family planning services, Marie Stopes International (MSI) Mali introduced social franchising in public-sector community health centers (referred to as CSCOMs in Mali) in 3 regions under the MSI brand BlueStar. Potential franchisees are generally identified from CSCOMs who have worked with MSI outreach teams; once accredited as franchisees, CSCOMs receive training, supervision, family planning consumables and commodities, and support for awareness raising and demand creation. To ensure availability and affordability of services, franchisees are committed to providing a wide range of contraceptive methods at low fixed prices. The performance of the BlueStar network from inception in March 2012 until December 2015 was examined using information from routine monitoring data, clinical quality audits, and client exit interviews. During this period, the network grew from 70 to 135 franchisees; an estimated 123,428 clients received voluntary family planning services, most commonly long-acting reversible methods of contraception. Franchisee efficiency and clinical quality of services increased over time, and client satisfaction with services remained high. One-quarter of clients in 2015 were under 20 years old, and three-quarters were adopters of family planning (that is, they had not been using a modern method during the 3 months prior to their visit). Applying a social franchising support package, originally developed for for-profit private-sector providers, to public-sector facilities in Mali has increased access, choice, and use of family planning in 3 regions of Mali. The experience of BlueStar Mali suggests that interventions that support quality supply of services, while simultaneously addressing demand-side barriers such as service pricing, can successfully create demand for a broad range of family

  18. Increasing Access to Family Planning Choices Through Public-Sector Social Franchising: The Experience of Marie Stopes International in Mali

    Science.gov (United States)

    Gold, Judy; Burke, Eva; Cissé, Boubacar; Mackay, Anna; Eva, Gillian; Hayes, Brendan

    2017-01-01

    Background: Mali has one of the world's lowest contraceptive use rates and a high rate of unmet need for family planning. In order to increase access to and choice of quality family planning services, Marie Stopes International (MSI) Mali introduced social franchising in public-sector community health centers (referred to as CSCOMs in Mali) in 3 regions under the MSI brand BlueStar. Program Description: Potential franchisees are generally identified from CSCOMs who have worked with MSI outreach teams; once accredited as franchisees, CSCOMs receive training, supervision, family planning consumables and commodities, and support for awareness raising and demand creation. To ensure availability and affordability of services, franchisees are committed to providing a wide range of contraceptive methods at low fixed prices. Methods and Results: The performance of the BlueStar network from inception in March 2012 until December 2015 was examined using information from routine monitoring data, clinical quality audits, and client exit interviews. During this period, the network grew from 70 to 135 franchisees; an estimated 123,428 clients received voluntary family planning services, most commonly long-acting reversible methods of contraception. Franchisee efficiency and clinical quality of services increased over time, and client satisfaction with services remained high. One-quarter of clients in 2015 were under 20 years old, and three-quarters were adopters of family planning (that is, they had not been using a modern method during the 3 months prior to their visit). Conclusion: Applying a social franchising support package, originally developed for for-profit private-sector providers, to public-sector facilities in Mali has increased access, choice, and use of family planning in 3 regions of Mali. The experience of BlueStar Mali suggests that interventions that support quality supply of services, while simultaneously addressing demand-side barriers such as service pricing

  19. Scaling up delivery of contraceptive implants in sub-Saharan Africa: operational experiences of Marie Stopes International

    Science.gov (United States)

    Duvall, Susan; Thurston, Sarah; Weinberger, Michelle; Nuccio, Olivia; Fuchs-Montgomery, Nomi

    2014-01-01

    Contraceptive implants offer promising opportunities for addressing the high and growing unmet need for modern contraceptives in sub-Saharan Africa. Marie Stopes International (MSI) offers implants as one of many family planning options. Between 2008 and 2012, MSI scaled up voluntary access to implants in 15 sub-Saharan African countries, from 80,041 implants in 2008 to 754,329 implants in 2012. This 9-fold increase amounted to more than 1.7 million implants delivered cumulatively over the 5-year period. High levels of client satisfaction were attained alongside service provision scale up by using existing MSI service delivery channels—mobile outreach, social franchising, and clinics—to implement strategies that broadened access for underserved clients and maintained service quality. Use of adaptive and context-specific service delivery models and attention to key operational components, including sufficient numbers of trained providers, strong supply chains, diverse financing mechanisms, and implant removal services, underpinned our service delivery efforts. Accounting for 70% of the implants delivered by MSI in 2012, mobile outreach services through dedicated MSI provider teams played a central role in scale-up efforts, fueled in part by the provision of free or heavily subsidized services. Social franchising also demonstrated promise for future program growth, along with MSI clinics. Continued high growth in implant provision between 2011 and 2012 in all sub-Saharan African countries indicates the region's capacity for further service delivery expansion. Meeting the expected rising demand for implants and ensuring long-term sustainable access to the method, as part of a comprehensive method mix, will require continued use of appropriate service delivery models, effective operations, and ongoing collaboration between the private, public, and nongovernmental sectors. MSI's experience can be instructive for future efforts to ensure contraceptive access and

  20. Demonstration of shield-type longwall supports at York Canyon Mine of Kaiser Steel Corporation. Final technical report A

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, R.G.; King, R.

    1980-04-01

    This report represents work on a program that was originated by the USBM of the Department of the Interior and was transferred to the Department of Energy on October 1, 1977. A demonstration with the Government funded Hemscheidt 320 HSL caliper type shield supports was conducted at three longwall panels of Kaiser Steel Corporation's York Canyon Mine. The purpose of this longwall demonstration was to provide the US coal industry with information on all aspects of shield longwall mining in high seams. The demonstration provided a working model for the coal industry and during the project, 350 people from the industry, schools, and government agencies visited the demonstration. They were provided with a first hand knowledge of a working shield longwall. The demonstration showed that the control of large coal lumps may be a problem in the mining of coal seam thicker than 8 feet. Mining with shield type supports provided good working conditions and a safe working environment. The shield requires very little maintenance and has a high mechanical availability.

  1. Implementation of state-of-art mining knowledge and technologies in design and operation of a safe and efficient deep gold mine stope for 21st Century.

    CSIR Research Space (South Africa)

    Van der Merwe, JN

    2001-02-01

    Full Text Available Final Project Report Implementation of state-of-art mining knowledge and technologies in design and operation of a safe and efficient deep gold mine stope for 21st Century van der Merwe, J. N., Wojno, L. and Toper, A. Z. Research agency : Rock... total of 2 years involvement) ...........68 13 1 Introduction 1.1 Research problem Assess the potential for underground implementation of state-of-art mining knowledge and technologies in the design and operation of a safe and efficient deep gold...

  2. Mechanical Characteristics of Superhigh-Water Content Material Concretion and Its Application in Longwall Backfilling

    Directory of Open Access Journals (Sweden)

    Xufeng Wang

    2017-10-01

    Full Text Available Superhigh-water content material (SCM has been widely utilized for goaf backfilling, grouting, and fire prevention and extinguishing. In this paper, the engineering mechanical characteristics of superhigh-water content material concretion (SCMC were studied for two types of backfilling technologies in longwall mining—open-type and pocket-type backfilling. The mechanical properties and responses of the SCMC were assessed under different cementation states, varying loading conditions and at different scales. The results indicate that: (1 the compressive and tensile strengths of SCMC specimens in different cementation states increase as the curing time increases—the SCMC formed by a mixture of SCM and gangues has higher strength than that of pure SCM; (2 the SCMC is under different loading and confinement conditions when different backfilling technologies is applied; however the strength of SCMC increases with curing time and decreases with water volume percentage; and (3 large-size specimens of pure SCMC enter into an accelerated creep state at a leveled load of 1.4 MPa. The effects of SCM backfilling on subsidence control has been verified by field applications. The results presented in this paper can provide data support for the optimization of backfill mining technology using SCM, as well as for the design of hydraulic supports parameters at longwall faces.

  3. Forecasts of methane concentration at the outlet of the longwall with caving area - case study

    Science.gov (United States)

    Badura, Henryk; Bańka, Piotr; Musioł, Dariusz; Wesołowski, Marek

    2017-11-01

    This paper presents the characteristics of methane hazard and prevention undertaken in the N-6 longwall of seam 330/2 in “Krupiński" coal mine. On the basis of methane concentration measurements conducted with the use of telemetric system, time series of the average and maximum methane concentration at the outlet of the longwall area were generated. It was ascertained that they exhibit a strong autocorrelation. Based on a series of the average methane concentration, a time series of ventilation methane content was created and a total methane content was calculated with the use of methane flow rate measurements in the demethanization system. It was ascertained that dependence between methane concentration and output on the examined day and on the previous day is weak and also that the dependence between methane concentration and air flow rate is very weak. Dependencies between ventilation methane content, total methane content and demethanization efficiency were also investigated. Based on forecasting models [1] developed earlier by H. Badura, forecasts have been made to predict the average and maximum methane concentrations. The measured values f methane concentration show a high level of accordance with forecasted ones.

  4. Field trials of aquifer protection in longwall mining of shallow coal seams in China

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, D.S.; Fan, G.W.; Liu, Y.D.; Ma, L.Q. [State Key Laboratory of Coal Resource & Mine Safety, Xuzhou (China)

    2010-09-15

    The large-scale mining of shallow coal seams has a significant impact on the overlying aquifers and surface ecological environment. To protect the aquifers and maximize the coal resource recovery, field trials were undertaken during the operation of the LW32201 in Bulianta coal mine, Shendong, China. With a severely weathered rock (SWR) layer and two key strata (KS) in the overlying strata, aquifer protection in longwall mining (APLM) relies mainly on the rapid advance. In some localized zones, special measures should be taken to achieve the APLM, including lowering mining height, backfill and slurry injection. To further understand the mechanism and applicable conditions of the APLM and validate the effectiveness of the APLM, variation of the water table in the aquifer was observed as the longwall face passed through the zone. This paper also discusses the mechanism and basic requirements of the APLM and the relationship between the fall of the water table and the surface subsidence. The results of the field trials indicated that APLM in shallow coal seams could be successful under suitable conditions.

  5. Seismic monitoring of ground caving processes associated with longwall mining of coal

    International Nuclear Information System (INIS)

    Hatherly, P.; Luo, X.; Dixon, R.; McKavanagh, B.

    1997-01-01

    At the Gordonstone Coal Mine in Central Queensland, Australia, a microseismic monitoring study was undertaken to investigate the extent of ground failure caused by longwall mining. Twenty seven triaxial geophones were deployed in three vertical boreholes and over a six week period more than 1200 events were recorded. The seismicity correlated with periods of longwall production and occurred mainly within the 250 m wide mining panel. There was an arcuate zone of activity which extended from behind the face, at the sides of the panel and up to 70 m ahead of the face in the middle. There was lesser activity to a depth of about 30 m into the floor. The focal mechanisms show that reverse faulting was dominant. The presence of activity and reverse faulting ahead of the face was an unexpected result. However, piezometer readings at the time of the study and subsequent numerical modelling have supported this finding. This was the first detailed microseismic monitoring study of caving in an Australian underground coal mine. 9 refs., 6 figs

  6. Mine roof support and method in longwall mining of thick mineral seams

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, T.L.

    1978-01-03

    A bi-directional shearing machine mines a longwall face at the bottom of a thick mineral seam in a retreat operation under the protection of a row of adjacent powered roof supports each of which extends in a direction transverse to the solid face. Progressive advance of these roof supports allows the overlying mineral strata to cave. Each roof support is separated into articulated forward and aft units provided with separate sets of hydraulic props and having their solid canopies interfitted in end-to-end relation. The bases of the two units are interconnected with a push-pull hydraulic ram which enables relative longitudinal movement between the two units so that they may be advanced independently along a common axis toward the solid longwall face as the work progresses. During the advance of the forward units to provide face support, plowing and loading of carved mineral on the gob side may proceed without interruption. To accelerate caving, the aft units are independently advanced with an attached gob side chain conveyor and gob plow retracted beneath their canopies for protection. Starting from this retracted position, the gob conveyor and gob plow are allowed to load gradually out into the flushed coal.

  7. Establishing and Scaling-Up Clinical Social Franchise Networks: Lessons Learned From Marie Stopes International and Population Services International.

    Science.gov (United States)

    Thurston, Sarah; Chakraborty, Nirali M; Hayes, Brendan; Mackay, Anna; Moon, Pierre

    2015-06-17

    In many low- and middle-income countries, a majority of people seek health care from the private sector. However, fragmentation, poor economies of scale, inadequate financing, political opposition, a bias toward curative services, and weak regulatory and quality control systems pose serious challenges for the private sector. Social franchising addresses a number of these challenges by organizing small, independent health care businesses into quality-assured networks. Global franchisors Marie Stopes International (MSI) and Population Services International (PSI) have rapidly scaled their family planning social franchising programs in recent years, jointly delivering over 10.8 million couple-years of protection (CYPs) in 2014-up 26% from 8.6 million CYPs just 1 year prior. Drawing on experience across MSI's 17 and PSI's 25 social franchise networks across Africa, Asia, and Latin America and the Caribbean, this article documents the organizations' operational approaches, challenges faced, and solutions implemented. The organizations provide intensive capacity building and support for private-sector providers, including clinical training, branding, monitoring quality of franchised services, and commodity support. In addition, franchising programs engage providers and clients through behavior change communication (BCC) and demand generation activities to raise awareness and to attract clients, and they implement initiatives to ensure services are affordable for the lowest-income clients. Social franchise programs offer the private sector a collective platform to better engage government in health policy advocacy and for integrating into new public health care financing and procurement mechanisms. The future of social franchising will require developing approaches to scale-up and sustain the model cost-effectively, selectively integrating other health services into the franchise package, and being responsive to evolving health care financing approaches with the potential

  8. Stability assessment of the stopes and crown pillar of the S’Argentera abandoned mines (Ibiza, Spain) using geomechanical classifications, an empirical approach and numerical analysis focused on a possible tourist exploitation

    International Nuclear Information System (INIS)

    Jordá-Bordehore, L.; Jordá-Bordehore, R.; Durán Valsero, J.J.; Romero-Crespo, P.L.

    2017-01-01

    The argentiferous lead mines of S’Argentera in Ibiza (Balearic Islands, Spain) are some abandoned underground workings from the first decade of the 20th century. The stability of the main stopes and the crown pillar of the mines has been evaluated - part of which is located below the road between Santa Eulalia and San Carles de Peralta. The possibility of allowing public access to the surface of the mining area and setting up a project of a “show mine” on the underground stopes and galleries is analysed. The stability is assessed with an empirical approach using the O index, the scaled span method and a stability graph together with a numerical approach. Results show that the stopes of the mines are globally stable but some lack an adequate safety factor. Therefore some local reinforcements and monitoring are needed. The finite element modelling in two dimensions yields realistic results on the current stope stability and possible rock falls which have already occurred. [es

  9. Effects of longwall coal mining on the hydrology of two appalachian stream valleys

    International Nuclear Information System (INIS)

    Johnson, K.L.

    1992-01-01

    In an effort to quantify the effects of longwall mining on local hydrology, an intensive data collection program was undertaken at two sites in the Northern Appalachian coal field where the depth of mining is 500-600 feet. Wells were drilled prior to mining at both sites so that water level, water quality, and aquifer transmissivity data could be obtained before and after mining. Streamflow measurements were also taken before and after mining to evaluate effects of mining on surface water. Water levels in wells dropped a maximum of 15 feet during undermining and then recovered to levels at or above premining levels. Groundwater quality was not degraded as a result of mining at either site. Aquifer transmissivity increased an order of magnitude after mining at both sites. Impacts of mining on streamflow at both sites were minimal

  10. Determination of Elastic Parameters of Near-Surface Layers Over Subsidence Trough Development During Longwall Exploitation

    Science.gov (United States)

    Mendecki, Maciej J.; Jochymczyk, Krzysztof; Zuberek, Wacław M.; Tomaszewska, Radosława

    2017-12-01

    Seismic and geodetic studies were carried out before, during, and after underground exploitation of a coal bed in Katowice - Kleofas Coal Mine, located in the Upper Silesia Coal Basin, Poland. Development of a subsidence trough was completed approximately 3 months after passage of a longwall exploitation in the coal seam. This was the time required for the subsidence trough to appear on the surface, which was confirmed by levelling measurements. Sharp changes in the elastic parameters were observed on each profile during subsidence trough development. This observation can result from changing tension and compression forces caused by increase and/or decrease of the elastic parameters of the rock mass. After completion of subsidence trough development, the rock mass appeared to return to its isotropic state and the observed changes ceased. Some minor fluctuations were noted, but they probably resulted from changes in groundwater levels, which might have affected the measured parameters.

  11. Stope face support systems

    CSIR Research Space (South Africa)

    Daehnke, A

    1998-12-01

    Full Text Available stream_source_info GAP330_2.pdf.txt stream_content_type text/plain stream_size 538 Content-Encoding ISO-8859-1 stream_name GAP330_2.pdf.txt Content-Type text/plain; charset=ISO-8859-1 ...

  12. Longwall mining “cutting cantilever beam theory” and 110 mining method in China—The third mining science innovation

    OpenAIRE

    Manchao He; Guolong Zhu; Zhibiao Guo

    2015-01-01

    With the third innovation in science and technology worldwide, China has also experienced this marvelous progress. Concerning the longwall mining in China, the “masonry beam theory” (MBT) was first proposed in the 1960s, illustrating that the transmission and equilibrium method of overburden pressure using reserved coal pillar in mined-out areas can be realized. This forms the so-called “121 mining method”, which lays a solid foundation for development of mining science and technology in Chin...

  13. Comprehensive study on the deformation and failure characteristics of a mining-impacted deep double-longwall working face floor

    Science.gov (United States)

    Zhu, Shuyun; Lu, Liangliang; Wu, Yun; Zhang, Tingting

    2017-06-01

    The key solution to the safe mining of coal over a deep confined aquifer is to obtain and understand the deformation and failure characteristics of the working face’s floor strata. In this work, we took a typical fully mechanized mining deep double-longwall working face floor of Chengjiao Coal Mine as a study case. Through in situ tests we established a three-range partition model for mining-induced underground pressure propagation in the coalbed floor to reveal the behavior of pressure propagation in both the vertical and horizontal directions of the floor strata. We found that the floor experienced consecutively three quantitative deformation ranges, and showed three different underground pressure behavior ranges the measured failure depth in the mining-induced double-longwall working faces floor was less than 27 m. In addition, the groups of rock mass were divided for mining the coal roof and floor, and we constructed a 3D engineering geological numerical model for the double-longwall working faces, and numerically simulated the plastic zone distribution features and the maximum vertical stress at different floor depths, finding that there were three stages for vertical stress along the mining coalbed floor depth. We also found that the failure depth of the floor was not more than 27 m by numerical simulation, consistent with the in situ measured result. All these results are of significance for the prevention and control of water inrush out of the double-longwall working face floor and for the support of their related roadways.

  14. Study on gob-side entry retaining technique with roadside packing in longwall top-coal caving technology

    Energy Technology Data Exchange (ETDEWEB)

    Hua, X. [China University of Mining and Technology, Beijing (China). Dept. of Resource and Safety Engineering

    2004-06-01

    The article points out some technical difficulties of gob-side entry retaining with roadside packing in longwall top-coal caving technology (LTCT), and analyzes the function mechanism of roadside filling body. Theory analysis shows the mechanical properties of high water material fit the feature of deformation of gob-side entry retaining in LTCT, and gob-side entry retaining in LTCT face is one of effective ways to increase the recovery ratio of the mining district. 3 refs., 1 fig.

  15. Private-Sector Social Franchising to Accelerate Family Planning Access, Choice, and Quality: Results From Marie Stopes International

    Science.gov (United States)

    Munroe, Erik; Hayes, Brendan; Taft, Julia

    2015-01-01

    Background: To achieve the global Family Planning 2020 (FP2020) goal of reaching 120 million more women with voluntary family planning services, rapid scale-up of services is needed. Clinical social franchising, a service delivery approach used by Marie Stopes International (MSI) in which small, independent health care businesses are organized into quality-assured networks, provides an opportunity to engage the private sector in improving access to family planning and other health services. Methods: We analyzed MSI’s social franchising program against the 4 intended outputs of access, efficiency, quality, and equity. The analysis used routine service data from social franchising programs in 17 African and Asian countries (2008–2014) to estimate number of clients reached, couple-years of protection (CYPs) provided, and efficiency of services; clinical quality audits of 636 social franchisees from a subset of the 17 countries (2011–2014); and exit interviews with 4,844 clients in 14 countries (2013) to examine client satisfaction, demographics (age and poverty), and prior contraceptive use. The MSI “Impact 2” model was used to estimate population-level outcomes by converting service data into estimated health outcomes. Results: Between 2008 and 2014, an estimated 3,753,065 women cumulatively received voluntary family planning services via 17 national social franchise programs, with a sizable 68% choosing long-acting reversible contraceptives (LARCs). While the number of social franchisee outlets increased over time, efficiency also significantly improved over time, with each outlet delivering, on average, 178 CYPs in 2008 compared with 941 CYPs in 2014 (P = .02). Clinical quality audit scores also significantly improved; 39.8% of social franchisee outlets scored over 80% in 2011 compared with 84.1% in 2014. In 2013, 40.7% of the clients reported they had not been using a modern method during the 3 months prior to their visit (95% CI = 37.4, 44

  16. Private-Sector Social Franchising to Accelerate Family Planning Access, Choice, and Quality: Results From Marie Stopes International.

    Science.gov (United States)

    Munroe, Erik; Hayes, Brendan; Taft, Julia

    2015-06-17

    To achieve the global Family Planning 2020 (FP2020) goal of reaching 120 million more women with voluntary family planning services, rapid scale-up of services is needed. Clinical social franchising, a service delivery approach used by Marie Stopes International (MSI) in which small, independent health care businesses are organized into quality-assured networks, provides an opportunity to engage the private sector in improving access to family planning and other health services. We analyzed MSI's social franchising program against the 4 intended outputs of access, efficiency, quality, and equity. The analysis used routine service data from social franchising programs in 17 African and Asian countries (2008-2014) to estimate number of clients reached, couple-years of protection (CYPs) provided, and efficiency of services; clinical quality audits of 636 social franchisees from a subset of the 17 countries (2011-2014); and exit interviews with 4,844 clients in 14 countries (2013) to examine client satisfaction, demographics (age and poverty), and prior contraceptive use. The MSI "Impact 2" model was used to estimate population-level outcomes by converting service data into estimated health outcomes. Between 2008 and 2014, an estimated 3,753,065 women cumulatively received voluntary family planning services via 17 national social franchise programs, with a sizable 68% choosing long-acting reversible contraceptives (LARCs). While the number of social franchisee outlets increased over time, efficiency also significantly improved over time, with each outlet delivering, on average, 178 CYPs in 2008 compared with 941 CYPs in 2014 (P = .02). Clinical quality audit scores also significantly improved; 39.8% of social franchisee outlets scored over 80% in 2011 compared with 84.1% in 2014. In 2013, 40.7% of the clients reported they had not been using a modern method during the 3 months prior to their visit (95% CI = 37.4, 44.0), with 46.1% (95% CI = 40.9, 51.2) of

  17. Determination of Particular Endogenous Fires Hazard Zones in Goaf with Caving of Longwall

    Science.gov (United States)

    Tutak, Magdalena; Brodny, Jaroslaw

    2017-12-01

    Hazard of endogenous fires is one of the basic and common presented occupational safety hazards in coal mine in Poland and in the world. This hazard means possibility of coal self-ignition as the result of its self-heating process in mining heading or its surrounding. In underground coal-mining during ventilating of operating longwalls takes place migration of parts of airflow to goaf with caving. In a case when in these goaf a coal susceptible to selfignition occurs, then the airflow through these goaf may influence on formation of favourable conditions for coal oxidation and subsequently to its self-heating and self-ignition. Endogenous fire formed in such conditions can pose a serious hazard for the crew and for continuity of operation of mining plant. From the practical point of view, a very significant meaning has determination of the zone in the goaf with caving, in which necessary conditions for occurrence of endogenous fire are fulfilled. In the real conditions determination of such a zone is practically impossible. Therefore, authors of paper developed a methodology of determination of this zone basing on the results of modelling tests. This methodology includes a development of model of tested area, determination of boundary conditions and carrying out the simulation calculations. Based on the obtained results particular hazardous zone of endogenous fire is determined. A base for development of model of investigated region and selection of boundary conditions are the results of real tests. In the paper fundamental assumption of developed methodology, particularly in a range of assumed hazard criterion and sealing coefficient of goaf with caving were discussed. Also a mathematical model of gas flow through the porous media was characterized. Example of determination of a zone particularly endangered by endogenous fire for real system of mining heading in one of the hard coal mine was presented. Longwall ventilated in the „Y” system was subjected to the

  18. Reconciling longwall gob gas reservoirs and venthole production performances using multiple rate drawdown well test analysis

    Energy Technology Data Exchange (ETDEWEB)

    Karacan, C. Oezgen [National Institute for Occupational Safety and Health (NIOSH), Pittsburgh Research Laboratory, Pittsburgh 15236, PA (United States)

    2009-12-01

    Longwall mining is an underground mining method during which a mechanical shearer progressively mines a large block of coal, called a panel, in an extensive area. During this operation the roof of the coal seam is supported only temporarily with hydraulic supports that protect the workers and the equipment on the coal face. As the coal is extracted, the supports automatically advance and the roof strata cave behind the supports. Caving results in fracturing and relaxation of the overlying strata, which is called ''gob.'' Due its highly fractured nature, gob contains many flow paths for gas migration. Thus, if the overlying strata contain gassy sandstones or sandstone channels, gas shales or thinner coal seams which are not suitable for mining, then the mining-induced changes can cause unexpected or uncontrolled gas migration into the underground workplace. Vertical gob gas ventholes (GGV) are drilled into each longwall panel to capture the methane within the overlying fractured strata before it enters the work environment. Thus, it is important, first to understand the properties of the gas reservoir created by mining disturbances and, second, to optimize the well parameters and placement accordingly. In this paper, the production rate-pressure behaviors of six GGVs drilled over three adjacent panels were analyzed by using conventional multi-rate drawdown analysis techniques. The analyses were performed for infinite acting and pseudo-steady state flow models, which may be applicable during panel mining (DM) and after mining (AM) production periods of GGVs. These phases were analyzed separately since the reservoir properties, due to dynamic subsidence, boundary conditions and gas capacity of the gob reservoir may change between these two stages. The results suggest that conventional well test analysis techniques can be applicable to highly complex gob reservoirs and GGVs to determine parameters such as skin, permeability, radius of investigation

  19. Optimization of daily output from a mechanized longwall face at the Bana Cigel mine

    Energy Technology Data Exchange (ETDEWEB)

    Horvath, F.

    1988-11-01

    Briefly reviews history of mechanized longwall coal mining in Slovakia, where daily face output grew from 329 t in 1965 to 563 t in 1986, while average number of faces fell from 84.1 to 36.1. Discusses various mathematical models which may be used for calculating daily output from mechanized faces (IGD Skochinskii model) and output per shift (Konikevich and Moiseev model) and a model of mechanized extraction equipment developed by E.I. Rogov, and lists main steps in the method applied to the Bana Cigel mine: selection of suitable monitoring method, measuring time and speed of operation, writing a BASIC computer program to process data, calculation of basic statistical information, regression and correlation analysis and evaluation of results. Data were processed on a KRS-4200 computer (GDR) and results showed that the most useful relationship for determining optimum daily output was that between amount of daily output and total time of operation of mining machinery. Small dispersion variance of regression curves also meant that daily output could be determined in relation to geological and technical mine parameters. 1 ref.

  20. Probabilistic modeling using bivariate normal distributions for identification of flow and displacement intervals in longwall overburden

    Energy Technology Data Exchange (ETDEWEB)

    Karacan, C.O.; Goodman, G.V.R. [NIOSH, Pittsburgh, PA (United States). Off Mine Safety & Health Research

    2011-01-15

    Gob gas ventholes (GGV) are used to control methane emissions in longwall mines by capturing it within the overlying fractured strata before it enters the work environment. In order for GGVs to effectively capture more methane and less mine air, the length of the slotted sections and their proximity to top of the coal bed should be designed based on the potential gas sources and their locations, as well as the displacements in the overburden that will create potential flow paths for the gas. In this paper, an approach to determine the conditional probabilities of depth-displacement, depth-flow percentage, depth-formation and depth-gas content of the formations was developed using bivariate normal distributions. The flow percentage, displacement and formation data as a function of distance from coal bed used in this study were obtained from a series of borehole experiments contracted by the former US Bureau of Mines as part of a research project. Each of these parameters was tested for normality and was modeled using bivariate normal distributions to determine all tail probabilities. In addition, the probability of coal bed gas content as a function of depth was determined using the same techniques. The tail probabilities at various depths were used to calculate conditional probabilities for each of the parameters. The conditional probabilities predicted for various values of the critical parameters can be used with the measurements of flow and methane percentage at gob gas ventholes to optimize their performance.

  1. Mechanism and Prevention of a Chock Support Failure in the Longwall Top-Coal Caving Faces: A Case Study in Datong Coalfield, China

    OpenAIRE

    Zhu Li; Jialin Xu; Shengchao Yu; Jinfeng Ju; Jingmin Xu

    2018-01-01

    Longwall chock support failures seriously restrain the safety and high-efficiency of mining of extra thick coal seams, as well as causing a great waste of coal resources. During longwall top-coal caving (LTCC), the influential effect of the properties and the movement regulation of top-coal on strata behavior cannot be ignored, since the top-coal is the medium through which the load of the overlying strata is transferred to the chock supports. Taking Datong coalfield as an example, the mechan...

  2. Satellite radar interferometry for monitoring subsidence induced by longwall mining activity using Radarsat-2, Sentinel-1 and ALOS-2 data

    Science.gov (United States)

    Ng, Alex Hay-Man; Ge, Linlin; Du, Zheyuan; Wang, Shuren; Ma, Chao

    2017-09-01

    This paper describes the simulation and real data analysis results from the recently launched SAR satellites, ALOS-2, Sentinel-1 and Radarsat-2 for the purpose of monitoring subsidence induced by longwall mining activity using satellite synthetic aperture radar interferometry (InSAR). Because of the enhancement of orbit control (pairs with shorter perpendicular baseline) from the new satellite SAR systems, the mine subsidence detection is now mainly constrained by the phase discontinuities due to large deformation and temporal decorrelation noise. This paper investigates the performance of the three satellite missions with different imaging modes for mapping longwall mine subsidence. The results show that the three satellites perform better than their predecessors. The simulation results show that the Sentinel-1A/B constellation is capable of mapping rapid mine subsidence, especially the Sentinel-1A/B constellation with stripmap (SM) mode. Unfortunately, the Sentinel-1A/B SM data are not available in most cases and hence real data analysis cannot be conducted in this study. Despite the Sentinel-1A/B SM data, the simulation and real data analysis suggest that ALOS-2 is best suited for mapping mine subsidence amongst the three missions. Although not investigated in this study, the X-band satellites TerraSAR-X and COSMO-SkyMed with short temporal baseline and high spatial resolution can be comparable with the performance of the Radarsat-2 and Sentinel-1 C-band data over the dry surface with sparse vegetation. The potential of the recently launched satellites (e.g. ALOS-2 and Sentinel-1A/B) for mapping longwall mine subsidence is expected to be better than the results of this study, if the data acquired from the ideal acquisition modes are available.

  3. The Effect of Power Protection Equipment on Explosion Hazards and on the Reliability of Power Supply to Longwall Systems

    Science.gov (United States)

    Boron, Sergiusz

    2017-06-01

    Operational safety of electrical machines and equipment depends, inter alia, on the hazards resulting from their use and on the scope of applied protective measures. The use of insufficient protection against existing hazards leads to reduced operational safety, particularly under fault conditions. On the other hand, excessive (in relation to existing hazards) level of protection may compromise the reliability of power supply. This paper analyses the explosion hazard created by earth faults in longwall power supply systems and evaluates existing protection equipment from the viewpoint of its protective performance, particularly in the context of explosion hazards, and also assesses its effect on the reliability of power supply.

  4. Three-dimensional experimental study of loose top-coal drawing law for longwall top-coal caving mining technology

    OpenAIRE

    Wang, Jiachen; Zhang, Jinwang; Song, Zhengyang; Li, Zhaolong

    2015-01-01

    Based on the loose medium flow field theory, the loose top-coal drawing law of longwall top-coal caving (LTCC) mining technology is studied by using self-developed three-dimensional (3D) test device. The loose top-coal drawing test with shields and the controlled test without shields are performed in the condition without any boundary effect. Test results show that shields will cause reduction in drawing volume of coal in the LTCC mining. The deflection phenomenon of drawing body is also obse...

  5. Supporting technology of roadside in gob-side entry in 110 longwall mining method

    Science.gov (United States)

    He, Manchao; Guo, Pengfei; Chen, Shangyuan; Gao, Yubing; Wang, Yajun

    2017-05-01

    To get better results of shaping roadside in 110 longwall mining method, the roadside support can be reasonably choose and designed through theoretical analysis, engineering test and other methods. The roadway support need to be designed based on the mining height and influence of mining pressure, and it is necessary to consider the "limited deformation" but also "given deformation". Because of the small mining high and short time under mining pressure effect in thin coal seam, roadside support can meet the requirements of block rock from gob using I-steel, but I-steel can't satisfy the deformation of roadway roof and easily lead to I-steel flexural buckling. In that condition we should use the U-steel that can compatible deformation with subsidence of roadway roof and enough torque in overlapping part between tow U-steel should be given when the U-steel is used to support gangue from gob and the U steel assembling two cards can coordinal deformation in dynamic pressure area keeping constant resistance with the deformation of roadway roof and can get a good effect. Through field test, due to the great impact force of the gangue from gob, single props and I-steel and U-steel are easily knocked down when the mining height is more than 4m. For large mining height, gangue blocking hydraulic support is designed and developed which can guarantee the stability and integrity of the roadway roof in the dynamic pressure area and can prevent the impact of gangue from gob. So it has better effect of forming roadway side using gangue from gob. According to above classification, the field experiments were carried out and obtained satisfactory results.

  6. Tactical and technological scheme of fire fighting in goaf left after longwall mining under conditions of methane combustion

    Energy Technology Data Exchange (ETDEWEB)

    Romanchuk, A.L.; Zrelyi, N.D.; Privalov, N.I.; Aleinikova, G.M.

    1981-07-01

    Presents recommendations on fire fighting in underground black coal mines. Situation when fire center is located in the goaf area left after longwall mining is analyzed. Fire fighting operations are divided into three stages: 1. fire fighting in the initial stage (installation of additional methane degassing means such as pipelines and pumps, pumping water, fire extinguishing foams or powders into fire center, ventilation, determining composition of the air in fire center), 2. intensification of fire fighting (increasing efficiency of degassing and fire extinguishing, improving ventilation of zone affected by the fire), 3. stage three occurs when fire extinguishing operations have been successful and consists in complete separation of the fire zone from the rest of the mine and from the ventilation system (changes in composition of fire gases and air are determined by automated instruments, injection of carbon dioxide or other inert gases, continuous deatatssing of the separated fire zone). Recommendations are listed in a detailed table. (In Russian)

  7. The design of a mechanical referencing system for the rear drum of the Longwall Shearer Coal Miner

    Science.gov (United States)

    Jones, E. W.; Yang, T. C. H.

    1981-01-01

    The design of two systems which reference the position of a longwall shearer coal miner to the mine roof of the present cut and of the last cut are presented. This system is part of an automation system that will guide the rear cutting drum in such a manner that the total depth of cut remains constant even though the front drum may be following an undulating roof profile. The rear drum referencing mechanism continually monitors the distance from the mine roof to the floor for the present cut. This system provides a signal to control a constant depth of cut. The last cut follower mechanism continually monitors the distance from the mine roof of the prior cut to the cutting drum. This latter system provides a signal to minimize the step height in the roof between cuts. The dynamic response of this hydraulic-pneumatic and mechanical system is analyzed to determine accumulator size and precharge pressure.

  8. Application of MASW method in studies on changes of soil elastic parameters over subsidence trough development during longwall exploitation

    Science.gov (United States)

    Mendecki, Maciej; Jochymczyk, Krzysztof

    2015-04-01

    The MASW method interpretation was applied to analyze 37 measurements which had been carried out to investigate spatial and temporal changes of elastic parameters in subsurface layers during extracting the coal bed. The seismic measurements were performed using the Terraloc apparatus containing 12 channels connected with 10 Hz geophones. 5 survey profiles were formed into a rosette with arms arranged relative about 45 degrees to each other. The research area was located in the Main Anticline, Upper Silesian Coal Basin, Southern Poland. The rosette was placed over the 201 longwall belonged to "Katowice - Kleofas" Coal Mine. Shallow geological structure consisted of subsurface soft layer (several meters) covered consolidated Carboniferous complex. Data interpretation were executed in winMASW software using the genetic algorithms to invert observed Rayleigh dispersion curve into S-wave velocity vertical profiles. In addition, the inversion allowed to determine parameters such as: density, thickness, shear modulus. The seismic study were carried out during total exploitation of the coal bed and for next 8 month after completion of mining works. Longer seismic observations than the mining works were due to a subsidence trough development over coal bed because the longwall face passage and subsidence trough development were shifted in time and it reached about 3 month. This time was needed to appear the subsidence trough on surface what was confirmed by leveling measurements. The longwall face had passed beneath the rosette in December, 1999 and in March, 2000 a sharp velocity drop on each profile was noticed. Next, a sudden velocity increase appeared in subsurface layer after the velocity drop. The changes of density and shear modulus was also remarked during the same period. At the beginning the sudden drop in velocity and other elastic parameters was associated with tension appeared on borders of subsidence trough. Then the geophysical profiles were in the compressive

  9. Powered supports for longwall mining systems using hydraulic or pneumatic stowing. Obudowy zmechanizowane do systemow wybierania scian z zastosowaniem podsadzki hydraulicznej i pneumatycznej

    Energy Technology Data Exchange (ETDEWEB)

    Pretor, W.; Sroka, H.; Trembaczewski, H. (Centrum Mechanizacji Gornictwa (Poland))

    1990-01-01

    Reviews Polish powered supports intended for equipment sets used at longwalls mined with hydraulic or pneumatic stowing. Specifications of powered supports of the FAZOS series are presented. Technical considerations and requirements met during development of subsequent modifications of the FAZOS supports are described. The first longwalls equipped with supports designed for mining with pneumatic stowing were put into operation in Poland in 1985. The supports used were the Polish FAZOS-17/277-POp, Hemscheidt BV-4700-13,5/26,5 and Czechoslovak MV-1 supports. The FAZOS supports developed in 1987 are also discussed. Stowing equipment used together with the various types of supports is described. Future developments are considered. Diagrammatic drawings of supports are presented.

  10. Observation measurement and analysis on strata pressure of fully mechanized longwall caving face in special thick seam

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.; Wu, J.; Li, B.; Liu, S.; Liang, J. [China University of Mining and Technology (China). Beijing Graduate School

    1997-09-01

    This paper introduces a fully mechanized longwall caving mining face in Weijiadi Mine, Gansu Province. The seam to be mined was a special thick seam with potential outbursts of coal and gas and spontaneous combustion. The average thickness of the seam was 12 m. The seam was mined with a one-pass method. Due to the softness of the coal body and the roof and floor, the strata support and bearing area of the coal face had to be moved in advance, slowly when the gateways became seriously deformed. The slow advancing had provided a condition for the spontaneous combustion of the residual coal in the goaf. Through observation, measurement and analysis of the strata in the coal face; the results revealed a rational support with hydraulic powered supports mainly to control the roof and the coal face, the distance of the periodical strata pressure was 20 to 35 m. The support resistance of the one-pass caving face was higher than the slicing mining face. The conveyor gateway of the caving face was seriously deformed and an advanced support of the gateway should have been made. 6 figs.

  11. Three-dimensional experimental study of loose top-coal drawing law for longwall top-coal caving mining technology

    Directory of Open Access Journals (Sweden)

    Jiachen Wang

    2015-06-01

    Full Text Available Based on the loose medium flow field theory, the loose top-coal drawing law of longwall top-coal caving (LTCC mining technology is studied by using self-developed three-dimensional (3D test device. The loose top-coal drawing test with shields and the controlled test without shields are performed in the condition without any boundary effect. Test results show that shields will cause reduction in drawing volume of coal in the LTCC mining. The deflection phenomenon of drawing body is also observed in the controlled test, which is verified that the deflection of drawing body is caused by shield. It is found that the deflection angle decreases with increasing caving height, with the maximum value of αtail and the minimum value of 0. In addition, the formula to calculate the drawing volume is proposed subsequently. The deflection of drawing body is numerically simulated using particle flow code PFC3D and the proposed formula to calculate drawing volume in LTCC is also verified.

  12. POSSIBILITIES OF EFFECTIVE INERTISATION OF SELF-HEATING PLACES IN GOAF OF LONGWALL IN HARD COAL MINES

    Directory of Open Access Journals (Sweden)

    Nikodem SZLĄZAK

    2016-10-01

    Full Text Available Underground fires in coal mines belong to the most common hazards, the exposure to which frequently requires long term and costly rescue operations. It is mainly connected with the specific character of underground excavations which have limited volume. This makes the maximum permissible concentration of harmful gases rapidly exceeded and may also cause changes in air flow direction. The most certain way of improving a safety situation in Polish coal mining indus-try is taking early prevention steps. One of the prevention methods is inertisation of the atmosphere in longwall goaf. These activities rely on partial or total replacement of air or combustible atmosphere by inert gas. Thanks to them the risk of spontaneous fires hazard and gas explosion decreases. The main reason for the use of inert gases is to reduce the oxygen content to a limit which prevents further development of fire. This article presents methods for assessing inert gas to replace oxygen in the atmosphere in goaf.

  13. Evaluation of the rockburst potential in longwall coal mining using passive seismic velocity tomography and image subtraction technique

    Science.gov (United States)

    Hosseini, Navid

    2017-09-01

    Rockburst is a typical dynamic disaster in underground coal mines which its occurrences relate to the mechanical quality of coal seam and surrounding rock mass and also the condition of stress distribution. The main aim of this paper is to study the potential of rockburst in a longwall coal mine by using of passive seismic velocity tomography and image subtraction technique. For this purpose, first by mounting an array of receivers on the surface above the active panel, the mining-induced seismic data as a passive source for several continuous days were recorded. Then, the three-dimensional tomograms using simultaneous iteration reconstruction technique (SIRT) for each day are created and by employing the velocity filtering, the overstressed zones are detected. In addition, the two-dimensional seismic velocity tomograms in coal seam level by slicing the three-dimensional tomograms are obtained. Then the state of stress changes in successive days by applying the image subtraction technique on these two-dimensional tomograms is considered. The results show that the compilation of filtered three-dimensional tomograms and subtracted images is an appropriate approach for detecting the overstressed zones around the panel and subsequent evaluation of rockburst potential. The research conclusion proves that the applied approach in this study in combination with field observations of rock mass status can effectively identify the rockburst-prone areas during the mining operation and help to improve the safety condition.

  14. Evaluate fundamental approaches to longwall dust control: Subprogram A, Passive barriers/spray air movers for dust control

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, J.; Ruggieri, S.

    1990-05-01

    One method to control shearer-generated dust on longwall faces is to confine the dust cloud to the face area and keep it away from face personnel as it travels downstream over the shearer body and beyond. Passive barriers can help this process by partitioning the airflow around the shearer into a clean split and a contaminated split. In addition, water sprays used as air movers (such as the Shearer Clearer developed on another USBM contract) aid the air partitioning process. A variety of passive barrier designs were developed and evaluated in the laboratory, tested in conjunction with the Shearer Clearer. The results showed that a headgate splitter arm'' to begin the airsplitting process is a vital part of a passive barrier system, whether or not a spray air moving system is also used on the shearer. A simple gob-side passive barrier along the edge of the shearer was also shown to help partition the airflow. Underground evaluations were conducted on a combination passive barrier/spray air moving system. The results confirmed the importance of the headgate splitter arm and showed that a gob-side barrier was very effective when used on shearers with ineffective external spray systems. The gob-side barrier was unnecessary, however, on shearers equipped with effective external air moving systems such as the Shearer Clearer. 32 figs., 14 tabs.

  15. Application of underground microseismic monitoring for ground failure and secure longwall coal mining operation: A case study in an Indian mine

    Science.gov (United States)

    Ghosh, G. K.; Sivakumar, C.

    2018-03-01

    Longwall mining technique has been widely used around the globe due to its safe mining process. However, mining operations are suspended when various problems arise like collapse of roof falls, cracks and fractures propagation in the roof and complexity in roof strata behaviors. To overcome these colossal problems, an underground real time microseismic monitoring technique has been implemented in the working panel-P2 in the Rajendra longwall underground coal mine at South Eastern Coalfields Limited (SECL), India. The target coal seams appears at the panel P-2 within a depth of 70 m to 76 m. In this process, 10 to 15 uniaxial geophones were placed inside a borehole at depth range of 40 m to 60 m located over the working panel-P2 with high rock quality designation value for better seismic signal. Various microseismic events were recorded with magnitude ranging from -5 to 2 in the Richter scale. The time-series processing was carried out to get various seismic parameters like activity rate, potential energy, viscosity rate, seismic moment, energy index, apparent volume and potential energy with respect to time. The used of these parameters helped tracing the events, understanding crack and fractures propagation and locating both high and low stress distribution zones prior to roof fall occurrence. In most of the cases, the events were divided into three stage processes: initial or preliminary, middle or building, and final or falling. The results of this study reveal that underground microseismic monitoring provides sufficient prior information of underground weighting events. The information gathered during the study was conveyed to the mining personnel in advance prior to roof fall event. This permits to take appropriate action for safer mining operations and risk reduction during longwall operation.

  16. A methodology for determining the evolution law of gob permeability and its distributions in longwall coal mines

    International Nuclear Information System (INIS)

    Zhang, Cun; Tu, Shihao; Zhang, Lei; Bai, Qingsheng; Yuan, Yong; Wang, Fangtian

    2016-01-01

    In order to understand the permeability evolution law of the gob by mining disturbances and obtain the permeability distribution of the fully compacted gob, comprehensive methods including theoretical analyses of monitoring data and numerical simulation are used to determine the permeability of gobs in the mining process. Based on current research, three zones of the vertical stress and permeability in the gob are introduced in this article, which are the caving rock mass accumulation zone, the gradually compacted zone and the fully compacted zone. A simple algorithm is written by using FISH language to be imported into the reservoir model. FISH language is an internal programming language in FLAC3D. It is possible to calculate the permeability at each zone with this algorithm in the mining process. Besides, we analyze the gas flow rates from seven gob gas ventholes (GGV) located on a longwall face operated in a mine of a Huainan coalfield in Huainan City, China. Combined with Darcy’s law, a calculation model of permeability around GGV in the gob is proposed. Using this model, the evolution law of permeability in the gob is deduced; the phases of permeability evolution are the decline stage and the stable stage. The result of the vertical stress monitoring data and good fitting effect of the permeability to the experimental data show that the permeability decline caused by the compaction of the gob is the principal reason for the decline stage. The stable stage indicates that the gob has been fully compacted, and the average period of full gob compaction is 47.75 d. The permeability in the middle of the compacted gob is much smaller than the permeability on the edge of the gob which presents an O shape trend. Besides, the little difference among the results of the numerical simulation, the permeability calculation model and other commonly used calculation models validate the correctness of the permeability calculation model and numerical simulation results

  17. Stochastic modeling of gob gas venthole production performances in active and completed longwall panels of coal mines

    Energy Technology Data Exchange (ETDEWEB)

    Karacan, C. Oezgen [NIOSH, Office of Mine Safety and Health Research, Pittsburgh, PA (United States); Luxbacher, Kray [Virginia Tech, Dept. of Mining and Minerals Engineering, Blacksburg, VA (United States)

    2010-11-01

    Gob gas ventholes (GGVs) are an integral part of longwall coal mining operations, enhancing safety by controlling methane in underground workings. As in many disciplines in earth sciences, uncertainties due to the heterogeneity of geologic formations exist. These uncertainties, and the wide range of mining and venthole operation parameters, lead to performance variability in GGVs. Random variations in parameters affecting GGV performance and influencing parameters that cannot be quantified sufficiently due to lack of information limit deterministic GGV models and even introduce error in severe cases. Therefore, evaluation of GGV performance data and the uncertainty in input parameters is valuable for understanding the variability in GGV production and for designing them accordingly. This paper describes a practical approach for implementing stochastic determination of GGV production performances and for generalizing the prediction capability of deterministic models. Deterministic site-specific models were derived by using the GGV module in the recently developed MCP (Methane Control and Prediction) software suite. These models were generated using multi-parameter regression techniques and were then improved by inclusion of extra input parameters that eliminated the site dependency and improved the predictions. Statistical distributions of input parameters in these models were quantified and tested with the Kolmogorov-Smirnov goodness-of-fit technique. Next, Monte Carlo simulations were performed using these distributions and generalized results for GGV performances were generated. The results of this work indicate that this approach is a promising method of representing the variability in GGV performances and to improve the limited and site-specific character of the deterministic models. (author)

  18. DETERMINATION OF THE ZONE ENDANGERED BY METHANE EXPLOSION IN GOAF WITH CAVING OF LONGWALLS VENTILATED ON „Y” SYSTEM

    Directory of Open Access Journals (Sweden)

    Jarosław BRODNY

    2016-10-01

    Full Text Available One of the most dangerous and most commonly present risks in hard coal mines is methane hazard. During exploitation by longwall system with caving, methane is emitted to mine heading from the mined coal and coal left in a pile. A large amount of methane also flows from neighboring seams through cracks and fissures formed in rock mass. In a case of accumulation of explosive methane concentration in goaf zone and with appropriate oxygen concentration and occur-rence of initials (e.g. spark or endogenous fire, it may come to the explosion of this gas. In the paper there are present-ed results of numerical analysis of mixture of air and methane streams flow through the real heading system of a mine, characterized by high methane hazard. The aim of the studies was to analyze the ventilation system of considered head-ing system and determination of braking zones in goaf zone, in which dangerous and explosive concertation of methane can occur with sufficient oxygen concentration equal to at least 12%. Determination of position of these zones is neces-sary for the selection of appropriate parameters of the ventilation system to ensure safety of the crew. Analysis of the scale of methane hazard allows to select such a ventilation system of exploitation and neighboring headings that ensures chemical composition of mining atmosphere required by regulation, and required efficiency of methane drainage. The obtained results clearly show that numerical methods, combined with the results of tests in real conditions can be suc-cessfully used for the analysis of variants of processes related to ventilation of underground mining, and also in the anal-ysis of emergency states.

  19. Blocking Underhand Attacks by Hidden Coalitions (Extended Version)

    OpenAIRE

    Cristani, Matteo; Karafili, Erisa; Viganò, Luca

    2010-01-01

    Similar to what happens between humans in the real world, in open multi-agent systems distributed over the Internet, such as online social networks or wiki technologies, agents often form coalitions by agreeing to act as a whole in order to achieve certain common goals. However, agent coalitions are not always a desirable feature of a system, as malicious or corrupt agents may collaborate in order to subvert or attack the system. In this paper, we consider the problem of hidden coalitions, wh...

  20. The Detection and Characterization of Urbanization, Industrialization, and Longwall Mining Impacts on Forest Ecosystems Through the Use of GiS and Remote Sensing Techniques

    Science.gov (United States)

    Pfeil-McCullough, Erin Kathleen

    Urbanization has far reaching and significant effects on forest ecosystems, directly through urban development and indirectly through supportive processes such as coal mining and agriculture. Urban processes modify the landscape leading to altered hillslope hydrology, increased disturbance, and the introduction of non-native forest pathogens. This dissertation addresses several challenges in our ability to detect these urbanization impacts on forests via geospatial analyses. The role of forests in urban hydrological processes has been extensively studied, but the impacts of urbanized hydrology on forests remain poorly examined. This dissertation documented impacts to hydrology and forests at variety of temporal and spatial scales: 1) A geospatial comparison of the historic and contemporary forests of Allegheny County, Pennsylvania revealed substantial shifts in tree species, but less change in the species soil moisture preference. These results document additional evidence that increased heterogeneity in urban soil moisture alters forest structure. 2) To examine soil moisture changes, impacts of longwall mine subsidence were assessed by using a Landsat based canopy moisture index and hot spot analysis tools at the forest patch scale. Declines in forest canopy moisture were detected over longwall mines as mining progressed through time, and results contradicted assumptions that the hydrological impacts overlying LMS recover within 4-5 years following subsidence of undermined land. 3) Utilizing a landslide susceptibility model (SINMAP), increases in landslide susceptibility were predicted in Pittsburgh, PA based on several scenarios of ash tree loss to the emerald ash borer (EAB), a bark beetle that rapidly kills ash trees. This model provides a tool to predict changes in landslide susceptibility following tree loss, increasing the understanding of urban forest function and its role in slope stability. Detecting how urbanized hydrology impacts forest health, function

  1. Mechanism and Prevention of a Chock Support Failure in the Longwall Top-Coal Caving Faces: A Case Study in Datong Coalfield, China

    Directory of Open Access Journals (Sweden)

    Zhu Li

    2018-01-01

    Full Text Available Longwall chock support failures seriously restrain the safety and high-efficiency of mining of extra thick coal seams, as well as causing a great waste of coal resources. During longwall top-coal caving (LTCC, the influential effect of the properties and the movement regulation of top-coal on strata behavior cannot be ignored, since the top-coal is the medium through which the load of the overlying strata is transferred to the chock supports. Taking Datong coalfield as an example, the mechanism of a chock support failure in the LTCC face was investigated. Research findings indicated that the hard top-coal and insufficient chock support capacity were primary reasons for chock support failure accidents. On account of the field-measured results, a new method to determine support capacity was proposed, which fully took the impact of the top-coal strength into consideration. The calculation revealed that the required support capacity had exceeded the existing production maximum, at about 22,000 KN. Since it was unrealistic to simply increase chock support capacity, other approaches, according to the theoretical analysis, were proposed, such as lowering the integrity and strength of the top-coal, and upgrading its crushing effect to weaken the support load effectively during the weighting period, which reduces the likelihood of chock support accidents occurring. Based on this, hydraulic fracturing for hard top-coal and optimization of the caving process (chock supports raised up and down repeatedly by manual operation before moving forward were presented. The proposed solutions were successfully applied in LTCC-west8101 for subsequent mining and achieved substantial benefits. The above research provides valuable references and ideas for the control of strata behavior to ensure safe and highly efficient mining in extremely thick and hard coal seams with the LTCC method.

  2. CMI and the simulated test stope

    CSIR Research Space (South Africa)

    Teleka, R

    2013-09-01

    Full Text Available The South African mining industry is plagued by accidents ranging from vehicle incidents to roof/rock falls. In the attempt to carry out its mandate of improving the quality of life of South African citizens, the Council for Scientific...

  3. Development of ZL400 Mine Cooling Unit Using Semi-Hermetic Screw Compressor and Its Application on Local Air Conditioning in Underground Long-Wall Face

    Science.gov (United States)

    Chu, Zhaoxiang; Ji, Jianhu; Zhang, Xijun; Yan, Hongyuan; Dong, Haomin; Liu, Junjie

    2016-12-01

    Aiming at heat injuries occurring in the process of deep coal mining in China, a ZL400 mine-cooling unit employing semi-hermetic screw compressor with a cooling capacity of 400 kW is developed. This paper introduced its operating principle, structural characteristics and technical indexes. By using the self-built testing platform, some parameters for indication of its operation conditions were tested on the ground. The results show that the aforementioned cooling unit is stable in operation: cooling capacity of the unit was 420 kW underground-test conditions, while its COP (coefficient of performance) reached 3.4. To address the issue of heat injuries existing in No. 16305 U-shaped long-wall ventilation face of Jining No. 3 coal mine, a local air conditioning system was developed with ZL400 cooling unit as the system's core. The paper presented an analysis of characteristics of the air current flowing in the air-mixing and cooling mode of ZL400 cooling unit used in air intake way. Through i-d patterns we described the process of the airflow treatment, such as cooling, mixing and heating, etc. The cooling system decreased dry bulb temperature on working face by 3°C on average and 3.8°C at most, while lowered the web bulb temperature by 3.6°C on average and 4.8°C at most. At the same time, it reduced relative humidity by 5% on average and 8.6% at most. The field application of the ZL400 cooling unit had gain certain effects in air conditioning and provided support for the solution of mine heat injuries in China in terms of technology and equipment.

  4. Modelling the behaviour of caving by the distinct element method: the case of longwall mining face. Modelisation du comportement du foudroyage par la methode des elements distincts: cas d'une longue taille

    Energy Technology Data Exchange (ETDEWEB)

    Al Heib, M.M.; Piguet, J.P.; Slimane, K.B. (INERIS, Nancy (France). Ecole des Mines de Nancy)

    1993-01-01

    The model simulates a longwall mining face. The behaviour of rock mass can be studied by using the distinct element methods. The authors are using numerical models for studying the interaction between the rock mass and the mining zone. The model particularly analyses the processes of the goaf phenomena but not the complete mechanism. The blocks' movement and the consequences to the environment (subsidence, stresses modification, etc...) are studied. The conditions for the first movement of goaf, the evolution and the concerned volume of rock are analysed. The methodology adopted follows three main steps: a consolidation phase without excavation in which the induced joints have a very high friction angle; simulation of longwall mining excavation; and the goaf processes. The joints of the goaf zone have a very small friction angle. The validation of the results is set up between the curve of in situ subsidence measurements and the values of a subsidence model. Thus, a comparison has been achieved between the results of finite element models and distinct element models. The results are encouraging for planification problems. 10 refs., 7 figs., 2 tabs.

  5. Inference of strata separation and gas emission paths in longwall overburden using continuous wavelet transform of well logs and geostatistical simulation

    Science.gov (United States)

    Karacan, C. Özgen; Olea, Ricardo A.

    2014-06-01

    Prediction of potential methane emission pathways from various sources into active mine workings or sealed gobs from longwall overburden is important for controlling methane and for improving mining safety. The aim of this paper is to infer strata separation intervals and thus gas emission pathways from standard well log data. The proposed technique was applied to well logs acquired through the Mary Lee/Blue Creek coal seam of the Upper Pottsville Formation in the Black Warrior Basin, Alabama, using well logs from a series of boreholes aligned along a nearly linear profile. For this purpose, continuous wavelet transform (CWT) of digitized gamma well logs was performed by using Mexican hat and Morlet, as the mother wavelets, to identify potential discontinuities in the signal. Pointwise Hölder exponents (PHE) of gamma logs were also computed using the generalized quadratic variations (GQV) method to identify the location and strength of singularities of well log signals as a complementary analysis. PHEs and wavelet coefficients were analyzed to find the locations of singularities along the logs. Using the well logs in this study, locations of predicted singularities were used as indicators in single normal equation simulation (SNESIM) to generate equi-probable realizations of potential strata separation intervals. Horizontal and vertical variograms of realizations were then analyzed and compared with those of indicator data and training image (TI) data using the Kruskal-Wallis test. A sum of squared differences was employed to select the most probable realization representing the locations of potential strata separations and methane flow paths. Results indicated that singularities located in well log signals reliably correlated with strata transitions or discontinuities within the strata. Geostatistical simulation of these discontinuities provided information about the location and extents of the continuous channels that may form during mining. If there is a gas

  6. Stability assessment of the stopes and crown pillar of the S’Argentera abandoned mines (Ibiza, Spain) using geomechanical classifications, an empirical approach and numerical analysis focused on a possible tourist exploitation; Evaluación de la estabilidad de las labores y pilar corona en las minas abandonadas de S’Argentera (Ibiza, España) combinando clasificaciones geomecánicas, métodos empíricos y análisis numérico - enfocado a su posible aprovechamiento turístico.

    Energy Technology Data Exchange (ETDEWEB)

    Jordá-Bordehore, L.; Jordá-Bordehore, R.; Durán Valsero, J.J.; Romero-Crespo, P.L.

    2017-09-01

    The argentiferous lead mines of S’Argentera in Ibiza (Balearic Islands, Spain) are some abandoned underground workings from the first decade of the 20th century. The stability of the main stopes and the crown pillar of the mines has been evaluated - part of which is located below the road between Santa Eulalia and San Carles de Peralta. The possibility of allowing public access to the surface of the mining area and setting up a project of a “show mine” on the underground stopes and galleries is analysed. The stability is assessed with an empirical approach using the O index, the scaled span method and a stability graph together with a numerical approach. Results show that the stopes of the mines are globally stable but some lack an adequate safety factor. Therefore some local reinforcements and monitoring are needed. The finite element modelling in two dimensions yields realistic results on the current stope stability and possible rock falls which have already occurred. [Spanish] Las minas de S’Argentera en Ibiza (Islas Baleares, España) son unas labores subterráneas de plomo argentífero abandonadas desde la primera década del siglo XX. Se ha analizado la estabilidad geotécnica de las cámaras y del pilar corona de las minas (sobre parte del cual pasa la carretera entre Santa Eulalia y San Carles de Peralta), dado que se está contemplando en un futuro permitir el acceso a la parte superior del conjunto de minas e iniciar un proyecto de rehabilitación turística de las labores subterráneas. Se ha evaluado la estabilidad combinando un enfoque empírico mediante el índice Q, método gráfico de estabilidad y ancho escalado, y métodos numéricos de elementos finitos para análisis tensodeformacional. El resultado del análisis muestra que las cámaras de las minas son estables pero algunas no poseen un adecuado factor de seguridad. Por lo tanto son necesarios algunos refuerzos y monitoreo puntuales. La modelización tensodeformacional en dos

  7. Chasing U-Boats and Hunting Insurgents: Lessons from an Underhand Way of War

    National Research Council Canada - National Science Library

    Breemer, Jan S

    2006-01-01

    .... Winston Churchill, then the Royal Navy's political head, was not willing to go quite that far, yet at one point during World War I, he ordered that captured U-boat crews be treated as criminals, not prisoners of war...

  8. Marie Stopes International Child Spacing Clinics in Malawi

    African Journals Online (AJOL)

    in child spacing is going to succeed. Some attitudes both among the men themselves and the service providers must change so that men feel that child spacing is also their concern and service providers feel men are not outsiders. Male medical staff should in particular pick up the challenge to start talking to their fellow.

  9. Ground motion studies in a backfilled stope at West Driefontein

    CSIR Research Space (South Africa)

    Goldbach

    1991-10-01

    Full Text Available stream_source_info Goldbach_1991.pdf.txt stream_content_type text/plain stream_size 24 Content-Encoding ISO-8859-1 stream_name Goldbach_1991.pdf.txt Content-Type text/plain; charset=ISO-8859-1 ...

  10. Unique Project of Single-Cutting Head Longwall Shearer Used for Thin Coal Seams Exploitation / Projekt Jednoorganowego Kombajnu ŚCIANOWEGO O Specjalnej Konstrukcji Przeznaczonego do Eksploatacji POKŁADÓW Cienkich

    Science.gov (United States)

    Bołoz, Łukasz

    2013-12-01

    Problem of thin hard coal seams exploitation, including chosen data related with their resources in Poland, has been discussed in the introduction of the present study. On the basis of actually operated machines the assumptions, which should be satisfied by the longwall shearer used for exploitation of thin hard coal seams, have been made. A project of such longwall shearer combined with band conveyor and mechanized longwall support, including description of the machine operation technology and analysis of possible day output achievement, have been presented. Polska dysponuje stosunkowo dużymi zasobami surowców energetycznych, a ciągle rosnące zapotrzebowanie na energię skłania do ich racjonalnego wykorzystywania. Jedną z możliwości takiego racjonalnego gospodarowania zasobami naturalnymi jest eksploatacja węgla kamiennego z pokładów cienkich. W związku z wybieraniem coraz cieńszych pokładów węgla, zalegających bardzo głęboko, w trudnych warunkach górniczo-geologicznych napotyka się na duże problemy związane z uzyskaniem wymaganej wydajności wydobycia przy użyciu stosowanych aktualnie metod. Przyjmuje się, ze pokłady cienkie to takie o miąższości od 1.0 m do 1.5 m i właśnie ta niewielka wysokość wyrobiska ścianowego powoduje szereg ograniczeń związanych z efektywną eksploatacją węgla. Na podstawie dostępnych danych określono, że ilości węgla kamiennego w cienkich pokładach wynosi około 600 mln Mg. Znaczna część pokładów cienkich w ostatnich latach została przeklasyfikowana na nieprzemysłowe, co pozwala stwierdzić, że rzeczywista ilość węgla w pokładach cienkich jest znacznie większa. Na podstawie analizy wad i zalet jak i danych technicznych produkowanych obecnie maszyn, określono wytyczne i założenia do nowego rozwiązania maszyny urabiającej przeznaczonej do wydobywania węgla w ścianach niskich. Kombajn do eksploatacji cienkich pokładów powinien spełniać następujące wymagania (Bołoz, 2012

  11. Geostatistical coal quality control in longwall mining

    Energy Technology Data Exchange (ETDEWEB)

    Hindistan, Mehmet Ali; Tercan, Abdullah Erhan; Uenver, Bahtiyar [Hacettepe University, Dept. of Mining Engineering, Beytepe, 06800 Ankara (Turkey)

    2010-03-01

    The coal quality is an important aspect of coal mine planning. This paper presents a case study in which an underground coal mine is faced with severe penalty cost because it does not consider in situ coal quality control at all. To help short term planning of the coal production the mean calorific values of the blocks inside the production panels are estimated by kriging. The estimated calorific values are compared with those obtained from actual production. The ratio of the calorific values of actual production to estimated values is found to be 0.73 in average due to adverse effect of dilution on the quality of run-of-mine coal. This study reveals the importance of geostatistical block modelling in short term mine planning. (author)

  12. An under-hand steering wheel grasp produces significant injury risk to the upper extremity during airbag deployment

    NARCIS (Netherlands)

    Hoof, J.F.A.M. van; Atkinson, P.; Telehowski, P.; Bir, C.

    2002-01-01

    Recent laboratory investigations suggest that a deploying airbag may fracture the forearm. These studies positioned the arm in an overhand grasp placing the forearm over the airbag module. However, there is little published data on how drivers grip the steering wheel and the general proximity of the

  13. Interaction between stope support and ground motion in the hangingwall and footwall Project.

    CSIR Research Space (South Africa)

    Cichowicz, A

    2002-07-01

    Full Text Available and limitations were verified by detailed testing with the strong ground motion data. The support response may be simulated using SDOF model when PGA is in the range 18 - 100 m/s2 ; for this data model shows that the maximal value of the stiffness is 120,000 k...

  14. Development of an effective face area support system for tabular stopes.

    CSIR Research Space (South Africa)

    Acheampong, E

    2002-03-01

    Full Text Available This report is an interim report of a two-year project, the first phase of which ended at the end of March 2002. The report therefore highlights progress made to date only.In SIMRAC project GAP708, eleven innovative means of reducing the rock...

  15. Stope gully support and sidings geometry at all depths and at varying dip.

    CSIR Research Space (South Africa)

    Naidoo, K

    2002-08-01

    Full Text Available gullies 201 References 203 Appendix 1 208 vii List of tables Table 2.1 Tendon support requirements to restrain falls over gullies (Roberts,1995) Table 2.2 Proportion of industry wide rock related fatalities that are gully related Table 2... pattern for Follow Behind Gully configuration (after Squelch & Roberts, 1995) Figure 2.18 A plan of a lead, or north side, between two panels showing the face shape (solid line) which it is usually tried to maintain by blasting and the shape (dashed...

  16. CSIR Center for Mining Innovation and the simulated test stope: Paper

    CSIR Research Space (South Africa)

    Teleka, R

    2013-01-01

    Full Text Available The South African mining industry is plagued by accidents ranging from vehicle incidents to roof/rock falls. In the attempt to carry out its mandate of improving the quality of life of South African citizens, the Council for Scientific...

  17. Review of the stoping problem - GS Review of past work rockbreaking

    CSIR Research Space (South Africa)

    Pickering, RGB

    1988-03-01

    Full Text Available Rockbreaking is the most basic of the operations required in mining and over the years has been subject of extensive research and development. This document is a summary of the work carried out by the Chamber of Mines Research Organization...

  18. New technology for real-time in-stope safety management

    CSIR Research Space (South Africa)

    Vogt, D

    2009-09-01

    Full Text Available working place, it then becomes possible for a team leader to monitor the state of the whole team, which should differentiate between individuals who are susceptible, and high effort or hot workplace. Additional sensors would confirm workplace... that knowledge to manage their heat stress programmes and ventilation. For example, PSI measured together with location may reveal areas where miners spend time that should be cooler to lower PSI, such as waiting places or stations. If PSI and workplace...

  19. Analysis and Optimization of Entry Stability in Underground Longwall Mining

    Directory of Open Access Journals (Sweden)

    Yubing Gao

    2017-11-01

    Full Text Available For sustainable utilization of limited coal resources, it is important to increase the coal recovery rate and reduce mine accidents, especially those occurring in the entry (gateroad. Entry stabilities are vital for ventilation, transportation and other essential services in underground coal mining. In the present study, a finite difference model was built to investigate stress evolutions around the entry, and true triaxial tests were carried out at the laboratory to explore entry wall stabilities under different mining conditions. The modeling and experimental results indicated that a wide coal pillar was favorable for entry stabilities, but oversize pillars caused a serious waste of coal resources. As the width of the entry wall decreased, the integrated vertical stress, induced by two adjacent mining panels, coupled with each other and experienced an increase on the entry wall, which inevitably weakened the stability of the entry. Therefore, mining with coal pillars always involves a tradeoff between economy and safety. To address this problem, an innovative non-pillar mining technique by optimizing the entry surrounding structures was proposed. Numerical simulation showed that the deformation of the entry roof decreased by approximately 66% after adopting the new approach, compared with that using the conventional mining method. Field monitoring indicated that the stress condition of the entry was significantly improved and the average roof pressure decreased by appropriately 60.33% after adopting the new technique. This work provides an economical and effective approach to achieve sustainable exploitation of underground coal resources.

  20. The peculiarities of structurizing enclosing rock massif while developing a coal seam

    Science.gov (United States)

    Kozyreva, E. N.; Shinkevich, M. V.

    2017-09-01

    Different concepts of the development of geo-mechanical processes during longwall mining of a seam which are fundamentally different from the conventional ones are introduced in the article. Fundamental principles of the model for structurizing enclosing rock mass while longwall mining along the strike are described. The model was developed on the bases of non-linear geomechanical laws. According to the model, rock mass in the area of mining operation is organized as rock geomechanical layers with shifting arches. And the formation period of shifting arches in disintegrated rock mass is divisible by the length of the stope. Undulate characteristic of a massif as a peculiarity of man-made structurization of a massif is defined. It is shown that structuring the broken massif causes the formation of block-structured system and it can be detected while monitoring the ground pressure in powered support props. The results of the research allow decreasing the negative influence of a ground pressure and can be applied to specify parameters for controlling the roof, defining geometrical dimensions of a mining section and positioning of holing chute (face entry).

  1. Functional specifications for in-stope support based on seismic and rockburst observations in South African mines

    CSIR Research Space (South Africa)

    Durrheim, RJ

    2012-03-01

    Full Text Available , such as prestressed elongates, roofbolts and nets. However, seismic theory and observations present several characteristics of seismically-induced ground motion that are not taken explicitly into account in the functional specifications for support design, i.e. multi...

  2. Extended use of the Savuka dynamic test facility to improve material and analytical technology in deep-level stope support.

    CSIR Research Space (South Africa)

    Ortlepp, WD

    2002-11-01

    Full Text Available .................................................. 17 Figure 5.1 Diagrammatic view of load-distribution pyramid and Voussoir beam showing position of Ebenhaeser timber elongates ............................... 18 Figure 5.2 View of pyramid and Voussoir beam showing the 3-prop spacing of test # 5...-dimensional load-distribution pyramid before impact................................................................................................... 48 9 Photograph 5.29 Test # 13, shortly after impact of first impulse of 88,4 kJ at velocity of 4,2 ms-1...

  3. Meaningful use of peak particle velocities at excavation surfaces for the optimisation of the rockburst criteria for tunnels and stopes.

    CSIR Research Space (South Africa)

    Milev, AM

    2002-03-01

    Full Text Available designed for recording strong ground motion was developed and manufactured. The instrument, a Peak Velocity Detector (PVD), is a portable battery powered stand-alone device with backed-up memory capable of storing up to 512 peak particle velocities... and manufactured: a Peak Velocity Detector (PVD). The instrument measures the peak particle velocity of a seismic wave propagating underground. The PVD is a portable battery powered stand-alone device with backed-up memory capable of storing up to 512 peak...

  4. Meaningful use of peak particle velocities at excavation surfaces for the optimisation of the rockburst criteria for tunnels and stopes

    CSIR Research Space (South Africa)

    Cichowicz, A

    2001-03-01

    Full Text Available '2$%#'(#$911'.\!&$#92)%.#$%!$/!,#-'*):#;8%#/'$&#!/1'.&*2&#*,,'/1-!$8/%2&#'(#/'2!&'.!23#!$#&8% /%*$9.%/%2&#'(#1%*<#3.'92)#*,,%-%.*&!'2#,*9$%)#=>#$&.'23#3.'92)#/'&!'2#!2#&8%#8*23!237*--+#(''&7*-- *2)#$911'.\!&$:#;8%#$&.'23%$&#/'2!&'.%)#1%*<#3.'92)#*,,%-%.*&!'2$#*.%#!2#&8%#.*23%#'(#?@#A#BBC/D$E 78...!,8+#*(&%.#!2&%3.*&!'2+#.%-*&%#&'#1%*<#3.'92)#6%-',!&>#!2#&8%#.*23%#'(#@:FG#A#@:GH#/D$:#;8%$%#1*.*/%&%.$ '(#$&.'23#3.'92)#/'&!'2#*.%#,*9$%)#=>#$%!$/!,#%6%2&$#'(#/*32!&9)%#B:E#A#E:G#'=$%.6%)#(.'/#)!$&*2,%$#'( C@#A#BG@/:##;8%#$&.'23%$.'92)#/'&!'2#7*$#/'2!&'.%)#=>#8'.!I'2&*-#*,,%-%.'/%&%.$#*2)#2'&+#*$#,'9-) =%#%J1...

  5. Particle velocity generated by rockburst during exploitation of the longwall and its impact on the workings

    Czech Academy of Sciences Publication Activity Database

    Holub, Karel; Rušajová, Jana; Holečko, J.

    2011-01-01

    Roč. 48, č. 6 (2011), s. 942-949 ISSN 1365-1609 Institutional research plan: CEZ:AV0Z30860518 Keywords : Ostrava-Karviná Coal Basin * rockburst * particle velocity * working damage Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 1.272, year: 2011 http://www.sciencedirect.com/science/article/pii/S1365160911000876

  6. Single-chip microcomputer based protection, diagnostic and recording system for longwall shearers

    Energy Technology Data Exchange (ETDEWEB)

    Heyduk, A.; Krasucki, F. (Politechnika Slaska, Gliwice (Poland). Katedra Elektryfikacji i Automatyzacji Gornictwa)

    1993-05-01

    Presents a concept of microcomputer-aided operation, protection, diagnostics and recording for shearer loaders. A two-stage mathematical model is suggested and explained. The model represents the thermal processes that determine the overcurrent protection of drive motors. Circuits for monitoring fuses, supply voltages, contacts, relays, contactors and electro-hydraulic distributors with the use of transoptors are shown. Recording characteristic operation parameters of a shearer loader during the 5 minutes before a failure is proposed. Protection, diagnosis and control functions are suggested as additional functions to the microcomputer-aided system of shearer loader control being developed at the Silesian Technical University. The system is based on the NECmicroPD 78310 microprocessor. 10 refs.

  7. Longwall mining and surface deformation – lessons learned from dInSAR measurements

    CSIR Research Space (South Africa)

    Engelbrecht, Jeanine

    2016-08-01

    Full Text Available including 1) subsidence related to mining and groundwater abstraction, 2) deformation following earthquake events, 3) monitoring of landslides and slope stability, 4) monitoring the stability of infrastructure and large engineering works, and 5) monitoring...

  8. Measurement and prediction of cutting forces and vibrations on longwall shearers

    Energy Technology Data Exchange (ETDEWEB)

    Bulent Tiryaki [CRCMining (Australia)

    2006-12-15

    CRCMining has developed the Cutting Head Performance Analysis Software (CPAS) to predict cutter motor power, ranging arm reaction forces, and vibrations for different drum designs, coal seams, and shearer operational conditions. This project describes the work on THE DBT EL3000 shearer at Beltana to validate/update CPAS by measuring the cutter motor power, ranging arm vibrations, and reaction forces through an online data acquisition system called Cutting Head Performance Monitoring System (CPMS). This system records the outputs of six strain gauge bridges, six accelerometers, and two pressure transducers on ranging arms during underground coal production. CPAS2 has then been developed in order to eliminate the needs for performing coal cutting tests for the target coal seam. CPAS2 simulations for cutter motor power, vertical reaction force, and vibrations were also close to those measured in the trials. CRCMining will release the CPAS code including fully functioning software code on CD to Australian coal mining industry.

  9. Comparison of coarse coal dust sampling techniques in a laboratory-simulated longwall section.

    Science.gov (United States)

    Patts, Justin R; Barone, Teresa L

    2017-05-01

    Airborne coal dust generated during mining can deposit and accumulate on mine surfaces, presenting a dust explosion hazard. When assessing dust hazard mitigation strategies for airborne dust reduction, sampling is done in high-velocity ventilation air, which is used to purge the mining face and gallery tunnel. In this environment, the sampler inlet velocity should be matched to the air stream velocity (isokinetic sampling) to prevent oversampling of coarse dust at low sampler-to-air velocity ratios. Low velocity ratios are often encountered when using low flow rate, personal sampling pumps commonly used in underground mines. In this study, with a goal of employing mine-ready equipment, a personal sampler was adapted for area sampling of coarse coal dust in high-velocity ventilation air. This was done by adapting an isokinetic nozzle to the inlet of an Institute of Occupational Medicine (Edinburgh, Scotland) sampling cassette (IOM). Collected dust masses were compared for the modified IOM isokinetic sampler (IOM-MOD), the IOM without the isokinetic nozzle, and a conventional dust sampling cassette without the cyclone on the inlet. All samplers were operated at a flow rate typical of personal sampling pumps: 2 L/min. To ensure differences between collected masses that could be attributed to sampler design and were not influenced by artifacts from dust concentration gradients, relatively uniform and repeatable dust concentrations were demonstrated in the sampling zone of the National Institute for Occupational Safety and Health experimental mine gallery. Consistent with isokinetic theory, greater differences between isokinetic and non-isokinetic sampled masses were found for larger dust volume-size distributions and higher ventilation air velocities. Since isokinetic sampling is conventionally used to determine total dust concentration, and isokinetic sampling made a difference in collected masses, the results suggest when sampling for coarse coal dust the IOM-MOD may improve airborne coarse dust assessments over "off-the-shelf" sampling cassettes.

  10. A Study of Mining-induced seismicity in Czech Mines with longwall coal exploitation

    Czech Academy of Sciences Publication Activity Database

    Holub, Karel

    2007-01-01

    Roč. 43, č. 1 (2007), s. 32-39 ISSN 1062-7391 R&D Projects: GA ČR GA205/03/0999 Institutional research plan: CEZ:AV0Z30860518 Keywords : induced seismicity * rockburst hazard * coal mines Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 0.293, year: 2007

  11. Effect of longwall face advance rate on spontaneous heating process in the gob area - CFD modelling

    Czech Academy of Sciences Publication Activity Database

    Taraba, B.; Michalec, Zdeněk

    2011-01-01

    Roč. 90, č. 8 (2011), s. 2790-2797 ISSN 0016-2361 R&D Projects: GA ČR GA105/06/0630 Grant - others:GA ČR(CZ) GA105/08/1414 Institutional research plan: CEZ:AV0Z30860518 Keywords : coal oxidation * spontaneous heating * CFD modelling * Fluent Subject RIV: DH - Mining, incl. Coal Mining Impact factor: 3.248, year: 2011 http://www.sciencedirect.com/science/article/pii/S0016236111001724

  12. Analysis of rockburst and rockfall accidents in relation to class of stope support, regional support, energy of seismic events and mining layout

    CSIR Research Space (South Africa)

    Cichowicz, A

    1994-01-01

    Full Text Available This report discusses the assessment of safety risk and the analysis of Falls Of Ground (FOG) in mines due to seismic events and mining layout during the period of 1991-1992 on a single mine. The multivariate analysis was used to obtain a...

  13. Detection of mining-induced fractures around a stope in Ezulwini gold mine, South Africa, by using AE events with similar waveforms

    CSIR Research Space (South Africa)

    Moriya, H

    2012-11-01

    Full Text Available The ability to predict rock failure is desirable for the prevention of disasters in mines. The acoustic emission (AE) method is a well-known tool for monitoring fracture growth in rock masses that is used to help ensure safety during excavations...

  14. Stability Control of Retained Goaf-Side Gateroad under Different Roof Conditions in Deep Underground Y Type Longwall Mining

    Directory of Open Access Journals (Sweden)

    Zhiyi Zhang

    2017-09-01

    Full Text Available Stability of the retained goaf-side gateroad (RGSG is influenced mainly by the movements of the roof strata near coal seam after coalface passes by. To make effective controlling technology for the stability of the RGSG, we analyze the roof structure over the RGSG to illustrate the mechanism causing the RGSG instability under different roof conditions. We then examine the dynamic evolution of the deformation and abutment stress in the rock surrounding the RGSG during coal seam mining, using the FLAC3D numerical software to reveal the instability characteristics of the RGSG under different roof conditions. Next, corresponding stability controlling technologies for the RGSGs are proposed and tested in three typical deep underground coalmines. Results show that: sink and rotation of the roof cantilever over the RGSG impose severer influence on the stability of the RGSG. The RGSG suffers disturbances three times during the coal-seam mining, and the deformation and abutment stress in the rock surrounding the RGSG increase significantly when the main roof becomes thicker and the immediate roof becomes thinner. Staged support technology involving grout cable bolts has better controlling results of the RGSG stability than that composed of conventional rock bolts, when the RGSG is beneath weak immediate roof with large thickness. Roof structure optimizing technology involving pre-split technology can improve the stability of the RGSG effectively when the RGSG is covered by hard main roof with large thickness directly.

  15. Design of Merensky Reef crush pillars

    CSIR Research Space (South Africa)

    Watson, BP

    2010-10-01

    Full Text Available variation of planar open stoping. Pillars are widely employed to support the open stopes. In the deeper levels, in-stope pillars are required to fail in a stable manner soon after being cut, and the residual pillar strength is used to stabilize the hanging...

  16. Stress–strain state of adjacent rock mass under slice mining of steeply dipping ore bodies

    Science.gov (United States)

    Baryshnikov, VD; Gakhova, LN

    2018-03-01

    Under analysis is the stress state of rock mass surrounding stopes in the initial cutting layer displaced in plan relative to the above-lying extracted layer in the overcut rock mass. The authors determine the boundaries of the post-limiting deformation zones during stoping advance using the Mohr–Coulomb criterion. The sequence of stoping to ensure better support conditions is proposed.

  17. 10th international conference on ground control in mining - proceedings

    International Nuclear Information System (INIS)

    Peng, S.S.

    1991-01-01

    36 papers are presented covering topics that include longwall pillar design, assessment of underground structural design, load and convergence measurements in longwall faces, shield strata interaction, longwall shield recovery, roof control in longwall mining, anchor resin system, thrust bolting, roof bolts, cable slings, roof support in retreat mining, coal bump prediction, delineation of abandoned workings, stability of coal mine openings, mining under rivers, rock strength determination, subsidence prediction and measurement, drag picks, measuring roof convergence, and finite element modelling of subsidence

  18. Impact of high-performance longwalls on the strata and on the surface; Der Einfluss von Hochleistungsstreben auf das Gebirge und die Tagesoberflaeche

    Energy Technology Data Exchange (ETDEWEB)

    Sroka, A. [Technische Univ. Bergakademie Freiberg, Freiberg (Germany)

    2003-09-01

    In this article is presented an influence of high-performance long wall on the earth's surface and on the rock mass. The phenomenon of the mining-damage on the buildings, unsteady rock mass reaction and of mining-induced microseismics was described and analyzed. (orig.) [German] Im Beitrag wird der Einfluss der Hochleistungstreben auf die Objekte der Tagesoberflaeche und auf das Gebirge dargestellt. Es werden die Phaenomene der Bergschaeden an Gebaeuden, der unstetigen Bodenreaktionen und der abbauinduzierten Seismik beschrieben und analysiert.

  19. Estimating of aquifer parameters from the single-well water-level measurements in response to advancing longwall mine by using particle swarm optimization

    Science.gov (United States)

    Buyuk, Ersin; Karaman, Abdullah

    2017-04-01

    We estimated transmissivity and storage coefficient values from the single well water-level measurements positioned ahead of the mining face by using particle swarm optimization (PSO) technique. The water-level response to the advancing mining face contains an semi-analytical function that is not suitable for conventional inversion shemes because the partial derivative is difficult to calculate . Morever, the logaritmic behaviour of the model create difficulty for obtaining an initial model that may lead to a stable convergence. The PSO appears to obtain a reliable solution that produce a reasonable fit between water-level data and model function response. Optimization methods have been used to find optimum conditions consisting either minimum or maximum of a given objective function with regard to some criteria. Unlike PSO, traditional non-linear optimization methods have been used for many hydrogeologic and geophysical engineering problems. These methods indicate some difficulties such as dependencies to initial model, evolution of the partial derivatives that is required while linearizing the model and trapping at local optimum. Recently, Particle swarm optimization (PSO) became the focus of modern global optimization method that is inspired from the social behaviour of birds of swarms, and appears to be a reliable and powerful algorithms for complex engineering applications. PSO that is not dependent on an initial model, and non-derivative stochastic process appears to be capable of searching all possible solutions in the model space either around local or global optimum points.

  20. The project of the mining method for the exploatation

    Directory of Open Access Journals (Sweden)

    Bauer Viliam

    1998-12-01

    Full Text Available This part of monography in a short form deals with the project of the block stoping mining - Open chamber stoping from sublevel drifts. In the paper is described the needs of mining method for tetrahedrite ores in Rožňava – Strieborná vein. The proposal block mining method is a very efficient, because use the LHD –system mechanization. The putting of this mechanization in the block enable relative high stope output achieve.

  1. Blasting forward in underground work; Voladuras de camara de la mina de Aguas Tenidas

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Maneiro, C. H.; Maqueda Jimenez, S.; Pazos Perez, L.; Carnero Ortiz, F.

    2012-11-01

    This paper explains the drilling and blasting techniques of stopes in Aguas Tenidas Mine (Huelva, Spain), including slot raises and slots. Highights are: application of electronic detonators and a 30'' hole in slot raise blasts, ANFO uphole chrging of 89 mm holes and high productive fan drillin, in order to maintain stoping production of 150.000 t/month. (Author)

  2. Feasibility of a mine-wide continuous closure monitoring system for gold mines.

    CSIR Research Space (South Africa)

    Malan, DF

    2000-09-01

    Full Text Available at Driefontein Consolidated Mine for the period 15/3/2000 to 22/3/2000. 20 3.1.2 Operating height (stoping width) In 1980 the average stoping width in the South African gold mining industry was estimated to be 1.33 m (Gay and Jager, 1980). Quite a significant...

  3. Merensky pillar strength formulae based on back-analysis of pillar failures at Impala Platinum

    CSIR Research Space (South Africa)

    Watson, BP

    2008-08-01

    Full Text Available variation of planar open stoping. Pillars are widely used to support the open stopes. Little work has been done in the past to determine pillar strength and pillars have been designed using experience and formulae developed for other hard-rock mines...

  4. Technological patterns of preventive relaxation of workings

    Energy Technology Data Exchange (ETDEWEB)

    Kaufman, L.L.; Bakhtin, A.F.; Zel' vyanskii, M.Sh. (Donetskaya Proektnaya Kontora (USSR))

    1991-09-01

    Presents stress relaxation patterns of workings. The patterns are used at horizon layouts and panel development of mine-take in stone inclines, boundary entries, mine drainage galleries and main galleries. The stress relaxation variants are: stress relaxing longwalls with complete mining with two or three winning galleries, longwalls worked by long pillars on the strike, and longwalls worked with advance mining on the strike. The individual variants differ by the ventilation system adopted.

  5. 30 CFR 75.817 - Cable handling and support systems.

    Science.gov (United States)

    2010-07-01

    ... High-Voltage Longwalls § 75.817 Cable handling and support systems. Longwall mining equipment must be provided with cable-handling and support systems that are constructed, installed and maintained to minimize... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Cable handling and support systems. 75.817...

  6. Experimental validation of a mine-wide continuous closure monitoring system as a decision making tool for gold mines.

    CSIR Research Space (South Africa)

    Malan, DF

    2003-03-01

    Full Text Available Previous fundamental research projects have indicated the value of continuous closure measurements for improved support design and hazard assessment and for quantifying the effect of seismicity on stope closure. This project examined the feasibility...

  7. Integrating cervical cancer screening and preventive therapy into ...

    African Journals Online (AJOL)

    CCS&PT) partnership brings together Marie Stopes International, Population Services International, the International Planned Parenthood Federation, and Society for Family Health to integrate CCS&PT services into existing Reproductive Health ...

  8. Develop a quantitative understanding of rockmass behaviour near excavations in deep mines, part 1

    CSIR Research Space (South Africa)

    Napier, JAL

    1995-12-01

    Full Text Available Control of the rock mass deformation near deep level stopes and the avoidance of damaging incidents of violent rock failure require a fundamental understanding of rock failure mechanisms. Research work to gain this understanding has been undertaken...

  9. Exploration on means and ways about increasing heap leaching rate

    International Nuclear Information System (INIS)

    Zhong Yongming

    2001-01-01

    The means and ways about increasing heap leaching (stope leaching and surface leaching) rate in the heap leaching process such as heap construction, lixiviant sprinkling, pregnant solution collecting and strengthened leaching etc. are explored

  10. Coal mining equipment

    International Nuclear Information System (INIS)

    Stein, R.R.; Martin, T.W.

    1991-01-01

    The word in longwall components is big, and these larger components have price tags to match. The logic behind the greater investment is that it will yield high production rates and good uptime statistics. This is true in most cases. More important than single-shift tonnage records, average shift production continues to climb upwards. This paper reports on the quality, and more significantly, the quantity of service supplied for long-wall equipment, which has reached levels that would have been seen as unachievable when longwall mining was first introduced in the U.S. The school of thought then was that longwall would increase productivity in part by reducing the number of production units and thus reducing the number of personnel employed underground. The expectation of fewer employees turned out to be unrealistic. That was probably one reason that some early attempts to install longwall system looked more like failures than vision of the future

  11. Remotely Piloted Aircraft and War in the Public Relations Domain

    Science.gov (United States)

    2014-10-01

    underhanded or de- ceitful. This article concerns itself with the genus of information, within which propaganda is a species, and therefore addresses all in... network may overlap (regarding a specific RPA strike, for example), that news network is not participating in al-Qaeda’s PR campaign. (Indeed, if it...the number of lives lost or the economic and social damage inflicted, but in the amount of media attention they are able to garner.”11 In what has

  12. Rock mechanics and the economics of cut-and-fill mining

    Energy Technology Data Exchange (ETDEWEB)

    Almgren, G.

    1980-05-15

    The application of rock mechanics to mining has great economic potential. Factors such as loss of ore, rock-dilution, possibilities of machanization and rock support are all influenced by the degree of rock mechanics involvement. In particular loss of ore is limited by the correct dimensioning of pillars and remnants. Rock-dilution, depending upon caving, can in the same way be mastered by the right dimensions of stopes and pillars and of rock supporting. Possibilities of mechanization depend upon sizes of drifts and stopes, stope availabilities and access to the stopes, all depending upon a considered rock mechanic investigation. Also shut-downs in the stopes owing to caving can be affected in the same way. Consequences on the mining economy for cut-and-fil mining are illustrated concerning loss of ore, rock-dilution, mechanization levels and rock support. The biggest influence can be made on rock-dilution and mechanization. Under special circumstances loss of ore can be of the same magnitude, namely if the ore production per year is directly influenced by the loss of ore and can not be compensated by other mining activities. Rock support is of less economic importance compared with rock-dilution and mechanization, presupposed no less of ore-production.

  13. 75 FR 34486 - Petitions for Modification

    Science.gov (United States)

    2010-06-17

    ... setting will also be sealed or locked; (4) replacement instantaneous trip units, used to protect pump... and de-energize the longwall mining machine at 1.5% methane. Methane levels will also be monitored by...

  14. Mining machinery - bigger and better

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-15

    The article describes the latest mining equipment available to meet the global demand for coal from some major manufacture - Atlas Copco, Caterpillar Global Mining, Joy Mining Machinery, Liebherr Great Britain Ltd., Longwall Associates and Sandvik. 6 photos.

  15. The possibilites of coal seam underground excavation in Republic of Macedonia with high productive excavation methods

    OpenAIRE

    Despodov, Zoran; Doneva, Nikolinka; Mijalkovski, Stojance

    2008-01-01

    The paper presents mining and geology properties of coal deposits in R.Macedonia predetermined for underground exploitation. Also it will be shown the way of coal seams preparation and development for underground excavation with longwall mining methods. Based on mining and geology properties of coal and it’s caloric value it will be observed the possibilities for application on the longwall mining which is among excavation methods with highest production and capacity applied in the contemp...

  16. Schemes for development and mining of level coal seams without leaving support coal pillars

    Energy Technology Data Exchange (ETDEWEB)

    Bakhtin, A.F.; Batmanov, Yu.K.; Taratuta, N.K.

    1982-07-01

    Methods are illustrated for longwall mining without leaving support pillars for strata control. Comparative evaluations in Soviet coal mines show that with increasing mining depth coal losses associated with support pillars increase. Use of support pillars also increases rock burst hazard and increases cost of support repairs in mine roadways. Proportion of coal from longwall mining without leaving coal support pillars increased from 36 % in 1976 to 52% in 1980. Two variants of longwall mining without support pillars are analyzed: with repeated use of longwall gate roads and without their repeated use. Comparative investigations show that longwall mining with the repeated use of the gates (one of the gate roads) is used in coal seams with the most convenient mining and geological conditions, whereas the second system is used under more difficult conditions. Schemes with repeated use are designed for thin coal seams, at a depth not exceeding 600 m, under conditions of stable roof and floor (when the floor consists of less stable rocks absence of water influx is the condition). Repeated use of gate roads is economical when, in spite of repeated gate road use, cost of support repair and maintenance is low. Fifteen schemes for longwall mining with and without repeated use of gateroads are compared. The results of evaluations are shown in a table. Recommendations on the most economical mining schemes are made.

  17. Neandertal humeri may reflect adaptation to scraping tasks, but not spear thrusting.

    Directory of Open Access Journals (Sweden)

    Colin N Shaw

    Full Text Available Unique compared with recent and prehistoric Homo sapiens, Neandertal humeri are characterised by a pronounced right-dominant bilateral strength asymmetry and an anteroposteriorly strengthened diaphyseal shape. Remodeling in response to asymmetric forces imposed during regular underhanded spear thrusting is the most influential explanatory hypothesis. The core tenet of the "Spear Thrusting Hypothesis", that underhand thrusting requires greater muscle activity on the right side of the body compared to the left, remains untested. It is unclear whether alternative subsistence behaviours, such as hide processing, might better explain this morphology. To test this, electromyography was used to measure muscle activity at the primary movers of the humerus (pectoralis major (PM, anterior (AD and posterior deltoid (PD during three distinct spear-thrusting tasks and four separate scraping tasks. Contrary to predictions, maximum muscle activity (MAX and total muscle activity (TOT were significantly higher (all values, p<.05 at the left (non-dominant AD, PD and PM compared to the right side of the body during spear thrusting tasks. Thus, the muscle activity required during underhanded spearing tasks does not lend itself to explaining the pronounced right dominant strength asymmetry found in Neandertal humeri. In contrast, during the performance of all three unimanual scraping tasks, right side MAX and TOT were significantly greater at the AD (all values, p<.01 and PM (all values, p<.02 compared to the left. The consistency of the results provides evidence that scraping activities, such as hide preparation, may be a key behaviour in determining the unusual pattern of Neandertal arm morphology. Overall, these results yield important insight into the Neandertal behavioural repertoire that aided survival throughout Pleistocene Eurasia.

  18. A law of removing radon by ventilation and air requirement calculation for eliminating radon daughters in uranium mines

    International Nuclear Information System (INIS)

    Wu Gang

    1988-06-01

    In accordance with testing data of removing radon and its daughters by ventilation from shrinkage and filling stopes of uranium mines, a law of removing radon by ventilation from the stopes is analyzed and summed. According to the decay law of radon and its daughters, an accumulation equation of potential alpha energy from radon daughters is presented with hyperbolic regression equation. the calculating formulae of ventilation flow are derived from the accumulation equation for eliminating radon daughters in inlet flow with or without contamination. It has been proved that the amount of ventilation air calcuated could meet the requirements of radiation safety rationally and economically

  19. The Coast Artillery Journal. Volume 91, Number 2, March-April 1948

    Science.gov (United States)

    1948-04-01

    the globe and, by devious under- gr ?und and ’underhand methods, to penetrate and under- nune the established social systems of manv lands " In a...Mexican Garrison at Juarez, Mexico, Gen- eral Enrique Diaz Gonzalez. The second was a review and presentation of colors and awards on 13 February. On this...34is one more fact of life, and a decisive one." It seems to him that "the \\;talitv of our Western culture will receive its gr ~t test in the use it

  20. Results of a backfill monitoring programme at Vaal Reefs 5 Shaft

    CSIR Research Space (South Africa)

    Squelch, AP

    1990-08-01

    Full Text Available This report documents the results of the in situ measurements carried out in the 68-52 stope at Vaal Reefs 5 Shaft. The in situ stress-strain behaviour of classified tailing backfill has been measured in panel P3. There is good agreement between...

  1. Report on the heat stroke position at the end of 1964

    CSIR Research Space (South Africa)

    Wyndham, CH

    1965-01-01

    Full Text Available The aim of this study for the Transvaal and Orange Free State Chamber of Mines Research Organization was to examine the heat stroke position at the end of 1964 in terms of the trends in the numbers of stopes and development ends and also...

  2. Numerical modelling approach for mine backfill

    Indian Academy of Sciences (India)

    Muhammad Zaka Emad

    2017-07-24

    Jul 24, 2017 ... Abstract. Numerical modelling is broadly used for assessing complex scenarios in underground mines, including mining sequence and blast-induced vibrations from production blasting. Sublevel stoping mining methods with delayed backfill are extensively used to exploit steeply dipping ore bodies by ...

  3. An acoustic sensor for prediction of the structural stability of rock

    CSIR Research Space (South Africa)

    Brink, S

    2016-05-01

    Full Text Available . The rock fall risks in deep rock mining are related to the behaviour of the rock surrounding excavations under high confining pressures. This is a particular concern in South African gold mines, where tunnels and stopes are excavated at depths of up to 4000...

  4. Can mine tremors be predicted? Observational studies of earthquake nucleation, triggering and rupture in South African mines

    CSIR Research Space (South Africa)

    Durrheim, RJ

    2012-05-01

    Full Text Available -related stresses are likely to induce significant seismic activity; (2) to learn more about earthquake rupture and damage phenomena by deploying strong ground motion sensors close to potential rupture zones and on the walls of stopes; and (3) to upgrade the South...

  5. Impact of soft loading conditions on the performance of elongate support elements.

    CSIR Research Space (South Africa)

    Daehnke, A

    2000-03-01

    Full Text Available rotating block and the resultant reaction force from the support units are brought closer together by increasing the support density (i.e. reducing the support spacing). The probability of blocks failing by rotating out of the hangingwall of a stope depends...

  6. Effect of face fracturing on shear wave coda quality factor estimated from acoustic emission events

    CSIR Research Space (South Africa)

    Kgarume, T

    2013-10-01

    Full Text Available The dependency of the quality factor derived from S wave coda (Q(subc)) on frequency is analysed in order to understand the effect of fracturing ahead of a mining stope. Micro seismic events recorded using acoustic emission sensors in a mining...

  7. Pain relief using paraceevical block in patients undergoing manual ...

    African Journals Online (AJOL)

    Objective: To evaluate pain relief using paracervical nerve block with 1% lignocaine injection in patients undergoing uterine evacuation by Manual Vacuum Aspiration (MVA) for the treatment of incomplete abortion. Design: A randomized double blind clinical trial. Setting: Marie Stopes Health Centre, Nairobi. Methods: One ...

  8. Geology and Environmental Impact Assessment and Benefit of ...

    African Journals Online (AJOL)

    Nigeria basement complex has shown that the older granites are high level intrusions emplaced by stoping and diapiric process and include spectrum of rocks varying in composition from tonalite through granodiorite to granite. The intense regional deformation which accompanied and preceded the emplacement of the ...

  9. REBOUND OF THE ROMANIAN CARD MARKET AFTER THE CRISIS AND ITS IMPACT ON THE BANKING PROFITABILITY

    Directory of Open Access Journals (Sweden)

    Magdalena RADULESCU

    2017-07-01

    Full Text Available The Romanian cards market relaunched after the crisis period, because the credit diminished or even stoped during 2008-2013, so the banks had to rely on the fees granted by issued cards or by banking payments operations. So, the total issued banking cards increased a lot during the last years and the electronic banking services developed.

  10. 40 CFR 146.5 - Classification of injection wells.

    Science.gov (United States)

    2010-07-01

    ... geothermal energy for heating, aquaculture and production of electric power. (13) Wells used for solution... conventionally mined. Solution mining of conventional mines such as stopes leaching is included in Class V. (3) Solution mining of salts or potash. (d) Class IV. (1) Wells used by generators of hazardous waste or of...

  11. 'bra, sɛn, yɛnkↄ... that is all i know in akan': how female migrants

    African Journals Online (AJOL)

    Dr. Obadele Kambon

    we discuss the incipient bilingualism as a major coping strategy among female migrants from Northern Ghana who work as Kayayei in three urban markets in Accra. The. Kayayei are popularly known as head porters in the literature on Ghanaian migration. (GHAFUP 2010, Alvin 2012, Osei-Boateng 2012, Marie Stopes ...

  12. Study of rockburst source mechanism

    CSIR Research Space (South Africa)

    Ortlepp, WD

    2000-06-01

    Full Text Available The research project comprising GAP 524 involved detailed examination of a group of 3 rockburst ruptures or burst-fractures discovered in a VCR stope panel on a peninsular remnant on Mponeng Mine at a depth of 2550m below surface. A careful visual...

  13. Effect of fly ash on the hydration process in cemented paste backfill at early stages

    Energy Technology Data Exchange (ETDEWEB)

    Simon, D.; Grabinsky, M.W. [Toronto Univ., ON (Canada). Dept. of Civil Engineering

    2009-07-01

    Cemented paste backfill (CPB) is a sustainable backfilling technique used in underground mining operations that ensures ground stabilization. The technique uses mine waste for filling the voids created by underground mining. Compared to conventional backfilling technologies, CPB has the advantage of rapid transport to the stopes; shorter turn-around cycle time; elimination of the drainage barricades in the CPB-filled stopes; and diversion of mine waste from surface disposal sites to underground stopes. Partial replacement of Portland cement with fly ash or ground blast furnace slag, can significantly reduce production costs and improve the performance of typical CPBs. This paper studied the effect of fly ash on the hydration process in CPB during the early stages of hydration using non-destructive, electromagnetic (EM) wave-based techniques. The study showed that the use of fly ash in Portland cement delayed the hydration process, and that the delay was proportional to the replacement level. At later onset times, the fly ash particles enhanced the hydration process by providing additional ions that contributed to the formation of hydration products and ultimately increased the mechanical strength of CPB. The EM test results on CPB obtained in the controlled laboratory environment were compared with in situ test results obtained in an actual backfilled test stope. The EM-wave based techniques were found to be sensitive to paste composition, including binder content, binder type and water content of the paste. 16 refs., 3 tabs., 6 figs.

  14. Numerical modelling approach for mine backfill

    Indian Academy of Sciences (India)

    Muhammad Zaka Emad

    2017-07-24

    Jul 24, 2017 ... pulse is applied as a stress history on the CRF stope. Blast wave data obtained from the on-site monitoring are very complex. It requires processing before interpreting and using it for numerical models. Generally, mining compa- nies hire geophysics experts for interpretation of such data. The blast wave ...

  15. The influence of lead length on the fractures associated with leading corners and sidings

    CSIR Research Space (South Africa)

    Turner, PA

    1989-02-01

    Full Text Available Stopes on three reef horizons and at various depths were examined in the vicinity of inter-panel leads. The general geometry of fractures in the vicinity of inter-panels leads is outlined. The extend of fracturing parallel to the siding between...

  16. In situ measurements of Merensky pillar behaviour at Impala Platinum

    CSIR Research Space (South Africa)

    Watson, BP

    2009-12-01

    Full Text Available to stabilize the stoping excavations. This paper describes the in situ measurement, of stress within a Merensky pillar from Impala Platinum. These measurements were used to derive a stress-strain curve that includes pre and post failure behaviour. 2D FLAC...

  17. Growth vs. decline

    Energy Technology Data Exchange (ETDEWEB)

    Morey, M.T.; Eyster, J.M. [PHB Hagler Bailly (USA)

    2000-04-01

    Production of high quality, low sulphur coal from mines in the western USA is in over supply. This situation is the result of increased production capacity from installing longwall technology, poor demand in international markets and growing competition from Powder River Basin coals at many domestic customer outlets. These factors have driven prices down by 10% since the beginning of 1999. With more longwall systems coming on line, low prices are set to continue. This should allow western US producers to compete in the international market for thermal coal, but only for as long as exporters are willing to accept the resulting low margins. 2 figs., 5 tabs., 2 photos.

  18. Third symposium on underground mining

    Energy Technology Data Exchange (ETDEWEB)

    None

    1977-01-01

    The Third Symposium on Underground Mining was held at the Kentucky Fair and Exposition Center, Louisville, KY, October 18--20, 1977. Thirty-one papers have been entered individually into EDB and ERA. The topics covered include mining system (longwall, shortwall, room and pillar, etc.), mining equipment (continuous miners, longwall equipment, supports, roof bolters, shaft excavation equipment, monitoring and control systems. Maintenance and rebuilding facilities, lighting systems, etc.), ventilation, noise abatement, economics, accidents (cost), dust control and on-line computer systems. (LTN)

  19. 76 FR 9374 - Proposed Extension of Existing Information Collection; Examinations and Testing of Electrical...

    Science.gov (United States)

    2011-02-17

    ... Testing of Electrical Equipment, Including High Voltage Longwalls AGENCY: Mine Safety and Health... on the right of the homepage. On the next screen, select ``Paperwork Reduction Act Supporting...: Extension. Agency: Mine Safety and Health Administration. OMB Number: 1219-0116. Frequency: Daily, weekly...

  20. Personal gravimetric dust sampling and risk assessment.

    CSIR Research Space (South Africa)

    Unsted, AD

    1996-03-01

    Full Text Available installation. The first underground site was a highly mechanized, shallow mine, the second site was a shallow mine with conventional mini-longwalls and the third site was a deep mechanized mine. The fourth site was an assay and sample preparation laboratory...

  1. 78 FR 78390 - Petitions for Modification of Application of Existing Mandatory Safety Standards

    Science.gov (United States)

    2013-12-26

    ... breaker as being suitable for protecting the cables. (4) Replacement circuit breakers and/or instantaneous... methane monitor(s) on the continuous mining machine or the longwall shear and face on the shift prior to... detector at least every 10 minutes from the time that mining with the continuous mining machine is within...

  2. Remote mining for in-situ waste containment. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Martinelli, D.; Banta, L.; Peng, S. [and others

    1995-10-01

    This document presents the findings of a study conducted at West Virginia University to determine the feasibility of using a combination of longwall mining and standard landfill lining technologies to mitigate contamination of groundwater supplies by leachates from hazardous waste sites.

  3. 30 CFR 75.823 - Scope.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Scope. 75.823 Section 75.823 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution High-Voltage Longwalls § 75.823 Scope...

  4. 78 FR 66911 - Texas Eastern Transmission, LP; Notice of Intent To Prepare an Environmental Assessment for the...

    Science.gov (United States)

    2013-11-07

    ... discuss the environmental impacts of the Emerald Longwall Mine Panel D1 Project in Docket No. CP14-4-000...) requires the Commission to take into account the environmental impacts that could result from an action... effects, reasonable alternatives, and measures to avoid or lessen environmental impacts. The more specific...

  5. Browse Title Index

    African Journals Online (AJOL)

    Items 1 - 50 of 132 ... N Uddin. Vol 39, No 2 (2003), Actual phenomenon of surface subsidence and bulking factor of caved rockmass in longwall panels of some coal mines in India, Details. SK Das. Vol 42, No 2 (2006), Aeromagnetic imaging of the basement morphology in part of the middle Benue trough, Nigeria, Abstract.

  6. Long-hole destress blasting for rockburst control during deep underground coal mining

    Czech Academy of Sciences Publication Activity Database

    Koníček, Petr; Souček, Kamil; Staš, Lubomír; Singh, R.

    -, č. 61 (2013), s. 141-153 ISSN 1365-1609 R&D Projects: GA MŠk ED2.1.00/03.0082 Institutional support: RVO:68145535 Keywords : Ostrava - Karvina Coal basin * longwall mining * rockbursts * destress blasting Subject RIV: DH - Mining, incl. Coal Mining Impact factor: 1.424, year: 2013 http://www.sciencedirect.com/science/article/pii/S1365160913000348

  7. 30 CFR 75.819 - Motor-starter enclosures; barriers and interlocks.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Motor-starter enclosures; barriers and...-Voltage Distribution High-Voltage Longwalls § 75.819 Motor-starter enclosures; barriers and interlocks. Compartment separation and cover interlock switches for motor-starter enclosures must be maintained in...

  8. System principles and evaluation criteria of reliability for optimization of technological parameters of coal deposits

    Directory of Open Access Journals (Sweden)

    A.О. Khorolskiy

    2017-12-01

    Full Text Available The article deals with solving the scientific problem of select mining equipment for selection longwall faces of mining venture. The main goal of the paper is to study technology of coal extraction of mining venture. The paper proposes a new approach to solve a problem of mining equipment selection for longwall faces of mining venture. The article describes new method for selection of mining equipment based on theory graph. Special attention is given to technological aspects; they are lenght of longwall faces, depth of coal stratum. Predictions obtained for daily production of mining equipment are compared with design outputs. Conclusions regarding the main reason of instability of longwall faces workings are made. It is found that to be able to use standard algorithms find the shortest path between vertices, you must perform matrix description of the constructed graphs that illustrate the structure of the interaction of different types of control equipment. Using classical optimization of method of discrete mathematics and algorithms for finding the shortest path between two vertices of network models obtained from the formalization of graphs with maximum results of specific types of equipment production chains, solved the problem of rational choice cleaning equipment for the new site with the cost parameters of the mining equipment and cost of mining coal. The authors developed effective and appropriate variants for the mine development for different coal deposits of mining venture.

  9. 30 CFR 75.342 - Methane monitors.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Methane monitors. 75.342 Section 75.342 Mineral... SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.342 Methane monitors. (a)(1) MSHA approved methane monitors shall be installed on all face cutting machines, continuous miners, longwall face...

  10. 30 CFR 75.325 - Air quantity.

    Science.gov (United States)

    2010-07-01

    ... coal by simply energizing the equipment on the section. (c) In longwall and shortwall mining systems... utilizing diesel-powered equipment in underground coal mines shall submit to the appropriate MSHA district... SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.325 Air quantity. (a)(1) In bituminous and...

  11. 30 CFR 70.1900 - Exhaust Gas Monitoring.

    Science.gov (United States)

    2010-07-01

    ... Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY HEALTH STANDARDS-UNDERGROUND COAL MINES DIESEL EXHAUST GAS MONITORING § 70.1900 Exhaust Gas... equipment on the longwall or shortwall face when mining equipment is being installed or removed; and (4) In...

  12. Remote mining for in-situ waste containment. Final report

    International Nuclear Information System (INIS)

    Martinelli, D.; Banta, L.; Peng, S.

    1995-10-01

    This document presents the findings of a study conducted at West Virginia University to determine the feasibility of using a combination of longwall mining and standard landfill lining technologies to mitigate contamination of groundwater supplies by leachates from hazardous waste sites

  13. Causes of falls of hangingwall over gullies adjacent to stabilizing strike pillars

    CSIR Research Space (South Africa)

    Turner, PA

    1987-08-01

    Full Text Available This report discusses the occurrence of falls of ground in strike gullies. Falls of hangingwall over strike gullies on the up-dip side of strike stabilizing pillars in longwall mining systems were investigated. Gullies were examined in both...

  14. Miners' dictionary: English/Fanakalo

    CSIR Research Space (South Africa)

    Chamber of Mines, South Africa

    1978-01-01

    Full Text Available . daw-kaw-tehl dolo d knee n. aw-law donga, wol wall dawng-gah, wall dongan (stope car) dong-gahn dongan stope car(end-tipping car) dong-gahn dongan switsh single-blade switch dawng-gahn switch dontsa pub v. dawnt-sah dontsa drag v. dawnt...-bee-lee mabili (e.g. you two) pair mah-bee-lee madala two mah-bee-lee madala hol (blasting) old mah-dah-lah madevu socket mah-dah-lah hawl madolo beard nIah-deh-voo madolo knee guards mah-daw-law madumelan, leg guards n mah-daw-Iaw madumelan, jackhammer...

  15. The hazardous nature of small scale underground mining in Ghana

    Directory of Open Access Journals (Sweden)

    K.J. Bansah

    2016-01-01

    Full Text Available Small scale mining continues to contribute significantly to the growth of Ghana's economy. However, the sector poses serious dangers to human health and the environment. Ground failures resulting from poorly supported stopes have led to injuries and fatalities in recent times. Dust and fumes from drilling and blasting of ore present health threats due to poor ventilation. Four prominent small scale underground mines were studied to identify the safety issues associated with small scale underground mining in Ghana. It is recognized that small scale underground mining in Ghana is inundated with unsafe acts and conditions including stope collapse, improper choice of working tools, absence of personal protective equipment and land degradation. Inadequate monitoring of the operations and lack of regulatory enforcement by the Minerals Commission of Ghana are major contributing factors to the environmental, safety and national security issues of the operations.

  16. Older people's reasoning about age-related prioritization in health care.

    Science.gov (United States)

    Werntoft, Elisabet; Hallberg, Ingalill R; Edberg, Anna-Karin

    2007-05-01

    The aim of this study was to describe the reasoning of people aged 60 years and over about prioritization in health care with regard to age and willingness to pay. Healthy people (n = 300) and people receiving continuous care and services (n = 146) who were between 60 and 101 years old were interviewed about their views on prioritization in health care. The transcribed interviews were analysed using manifest and latent qualitative content analysis. The participants' reasoning on prioritization embraced eight categories: feeling secure and confident in the health care system; being old means low priority; prioritization causes worries; using underhand means in order to be prioritized; prioritization as a necessity; being averse to anyone having precedence over others; having doubts about the distribution of resources; and buying treatment requires wealth.

  17. Privacy with Public Access: Digital Memorials on QR Codes

    DEFF Research Database (Denmark)

    Gotved, Stine

    2015-01-01

    takes the departure in gravestones with QR-codes; objects at once physical and digital, underhandedly putting presumably private content within public reach. A plethora of issues of privacy and publicness are at play within the study's two connected but rather different empirical spaces: the physical......Digital memorials are part of a bigger picture of changing rituals for mourning, remembrance, and legacy. However, the focus of this presentation is how digital memorials perforate the (already uneasy) distinction between private and public, both in physical and emotional space. The ongoing study...... in the borderland between private and public is exemplified, and with the presentation, we are ensuring a continued discussion on privacy as well as legacy in our digital society....

  18. Impact of social franchising on contraceptive use when complemented by vouchers: a quasi-experimental study in rural Pakistan

    OpenAIRE

    Azmat, Syed Khurram; Shaikh, Babar Tasneem; Hameed, Waqas; Mustafa, Ghulam; Hussain, Wajahat; Asghar, Jamshaid; Ishaque, Muhammad; Ahmed, Aftab; Bilgrami, Mohsina

    2013-01-01

    Background: Pakistan has had a low contraceptive prevalence rate for the last two decades; with preference for natural birth spacing methods and condoms. Family planning services offered by the public sector have never fulfilled the demand for contraception, particularly in rural areas. In the private sector, cost is a major constraint. In 2008, Marie Stopes Society - a local NGO started a social franchise programme along with a free voucher scheme to promote uptake of IUCDs amongst the poor....

  19. Mining robotics sensors

    CSIR Research Space (South Africa)

    Green, JJ

    2012-04-01

    Full Text Available sources, and techniques such as surfel modeling and synthetic view generation are explored towards creating visualizations of the data that could be used by miners to monitor areas of risk in the stope. Further work will determine this potential.... Index Terms?underground mining robotics, perception sensors, sensor fusion, infrared camera, 3D laser scan. I. INTRODUCTION To date, robotics in the mining industry has seen much advancement in automation for above-ground applications where...

  20. Disposal of solid radioactive waste of nuclear power plant

    International Nuclear Information System (INIS)

    YU Shichen.

    1986-01-01

    The contaminations of marine enviroment by the disposal of radwastes should not been expected, then ocean disposal has been stoped in some countries, and land disposal of solid radwastes should been a better method for mankind and environment protection. Ground burial near the surface is currently considered to be feasible. Storage in spent pit or in plant area also should been adapted in several countries

  1. Point-cloud registration using 3D shape contexts

    CSIR Research Space (South Africa)

    Price, M

    2012-11-01

    Full Text Available by stitching multiple sets of locally registered scans. We have gathered data from several underground mine stopes and found that the sensors are well suited to the unlit dusty environment. III. REGISTRATION WITH DESCRIPTORS Computing a registered 3D... surface with descriptors is closely related to the method used to create panoramas from 2D photos, often called image stitching [6]. Interesting points (keypoints) are detected in each image; local descriptors are computed around each keypoint...

  2. Geotechnical applications of a two-dimensional elastodynamic displacement discontinuity method

    CSIR Research Space (South Africa)

    Siebrits, E

    1993-12-01

    Full Text Available horizontally, and assuming a Mohr-Coulomb failure criterion with cohesion 10 MPa and friction angle 30 ?. Static excess shear stress is the shear stress available to trigger a shear-based event \\[15\\]. The static excess shear... stopes and the fault, the driving force being the applied static excess shear stress obtained from the static calculation. The dynamic friction angle and dynamic cohesion are assumed to be zero along the fault, which...

  3. Delineation of rockburst fractures with ground penetrating radar in the Witwatersrand Basin, South Africa

    CSIR Research Space (South Africa)

    Grodner, M

    2001-09-01

    Full Text Available hypotheses on the change in the fracturing ahead of the stope with preconditioning and delineate the zone of influence of each precondition- ing hole. This allowed the design of a preconditioning methodology that has lead to a major reduction in the incidence.... This increased understanding of rockbursts, allows the rock mechanics practitioner to better design strategies for the alleviation of rockbursts. Acknowledgements The Safety in Mines Research Advisory Committee (SIMRAC) is thanked for permission to publish. All...

  4. Epigene and Hypogene Gypsum Karst Manifestations of the Castile Formation: Eddy County, New Mexico and Culberson County, Texas, USA

    OpenAIRE

    Stafford Kevin W.; Nance Raymond; Rosales-Lagarde Laura; Penelope J. Boston

    2008-01-01

    Permian evaporites of the Castile Formation crop out over ~1,800 km2 in the western Delaware Basin (Eddy County, New Mexico and Culberson County, Texas, USA) with abundant and diverse karst manifestations. Epigene karst occurs as well-developed karren on exposed bedrock, while sinkholes dominate the erosional landscape, including both solutional and collapse forms. Sinkhole analyses suggest that more than half of all sinks are the result of upward stoping of subsurface voids, while many solut...

  5. Method of gas emission control for safe working of flat gassy coal seams

    Science.gov (United States)

    Vinogradov, E. A.; Yaroshenko, V. V.; Kislicyn, M. S.

    2017-10-01

    The main problems at intensive flat gassy coal seam longwall mining are considered. For example, mine Kotinskaja JSC “SUEK-Kuzbass” shows that when conducting the work on the gassy coal seams, methane emission control by means of ventilation, degassing and insulated drain of methane-air mixture is not effective and stable enough. It is not always possible to remove the coal production restrictions by the gas factor, which leads to financial losses because of incomplete using of longwall equipment and the reduction of the technical and economic indicators of mining. To solve the problems, the authors used a complex method that includes the compilation and analysis of the theory and practice of intensive flat gassy coal seam longwall mining. Based on the results of field and numerical researches, the effect of parameters of technological schemes on efficiency of methane emission control on longwall panels, the non-linear dependence of the permissible according to gas factor longwall productivity on parameters of technological schemes, ventilation and degassing during intensive mining flat gassy coal seams was established. The number of recommendations on the choice of the location and the size of the intermediate section of coal heading to control gassing in the mining extracted area, and guidelines for choosing the parameters of ventilation of extracted area with the help of two air supply entries and removal of isolated methane-air mixture are presented in the paper. The technological scheme, using intermediate entry for fresh air intake, ensuring effective management gassing and allowing one to refuse from drilling wells from the surface to the mined-out space for mining gas-bearing coal seams, was developed.

  6. Stability Control of Underground Roadways Subjected to Stresses Caused by Extraction of a 10-m-Thick Coal Seam: A Case Study

    Science.gov (United States)

    Chen, Yong; Ma, Shuqi; Yu, Yang

    2017-09-01

    Extraction of a 10-m-thick coal seam in one single lift using the longwall top coal caving method caused severe deformations in underground roadways in Majialiang coal mine in Shanxi Province, China. Field monitoring of stress changes in the roof and in the coal pillar, and deformation of the 14202 tailgate, were carried out. The deformation monitoring found that the maximum floor heave of the 14202 tailgate was 1.85 m when the monitoring point was 250 m behind the longwall working face, while the maximum roof subsidence and the maximum rib-rib convergence was 0.93 and 1.14 m, respectively. The deformation rate of the 14202 tailgate increased dramatically when the monitoring point was at distances of 100-150 m behind the longwall working face, which reflected the fact that the tailgate underwent sharply increased loads within this range. Field monitoring of stress changes and the displacement of the 14202 tailgate revealed that the impact range of the mining-induced stresses in longitudinal direction (the same as the mining direction) was from 60 m ahead of the longwall face to 250 m behind the longwall face. Additionally, the mining impact range in transverse direction was more than 45 m, indicating that the coal pillar width should be larger than 45 m to avoid significant influences of mining-induced stresses. This finding was applied to the 14103 tailgate, which was subjected to similar mining and geological conditions as the 14202 tailgate. A coal pillar with width of 56 m was adopted in the 14103 tailgate, and displacement monitoring showed that large deformation was successfully controlled. The field investigations in this study provide a basis for design of a proper coal pillar width of underground roadways when subjected to large stresses induced by mining of thick coal seams in a single lift.

  7. STRUCTURE OF ISOLATED PRECISION FACTORS OF THE MALE STUDENT ON VOLLEYBALL

    Directory of Open Access Journals (Sweden)

    Bahri Gjinovci

    2015-06-01

    Full Text Available The aim of this study was to verify the current status of accuracy in volleyball for the students of the faculty of physical education and sports of the University of Prishtina, all the students have successfully passed the exam in volleyball. Also, another aim was to observe whether there are significant statistical differences between both generations of students. In the study were included 70 students (35 from the second academic year and 35 from the fourth academic year. To achieve the aim, were applied standard tests of accuracy in volleyball, such as the following: overhand pass, underhand pass, as well as underhand serve on the six positions and float (tactic serve on three positions. From the basic statistical parameters, it has been noticed that grouping of results from the students of forth academic year are more homogenous, and for this group showed that results are better than at students of first year of studying. While, in the variables is noticed that there are changes into the favour of students of fourth academic year, it has also been noticed that standard deviation is smaller with this group, which shows even more homogenous groups, for example, SFIP group 1 mean 21.65 ±6.48 SD, gr.2 mean 23.68 ±5.76 SD. The obtained results from T-test shows significant statistical changes in both applied tests. The best obtained results are a derivate of continuous professional work, as well as result of “selection”, due to continuous testing and completion of both exams of hand sports and volleyball as an elective subject.

  8. Methodology of simulation of underground working in metal mines. Application to a uranium deposit in Australia

    International Nuclear Information System (INIS)

    Deraisme, J.; de Fouquet, C.; Fraisse, H.

    1983-01-01

    For the Ben Lomond (Northern Queensland Australia) underground uranium mining project, studies were carried out to compare the feasibility of different mining methods according to their cost per ton and selectivity, i.e. cut and fill, sublevel stopping and both mixed. First, a geostatistical orebody model was built. The ore grade variability of this model results from the drillhole structural analysis. Working on two dimensional vertical cross sections, the usual hand drawing stope reserve estimate obtained with computer assisted design for each of the three different mining methods is compared with the results obtained with automatic algorithms allocated to the characteristics of each mining method. These algorithms use mathematical morphology to reproduce the geometrical constraints connected with each mining method and/or dynamic programmation. These techniques lead to fully automatic of optimal economical stope design. Comparison is positive: automatic stopes designs are in agreement with hand made drawings, but they can be defined faster through interactive questionning of the computer, and the total maximum profit obtained is a least as high as the best profit found through hand designed projects [fr

  9. Classification Identification of Acoustic Emission Signals from Underground Metal Mine Rock by ICIMF Classifier

    Directory of Open Access Journals (Sweden)

    Hongyan Zuo

    2014-01-01

    Full Text Available To overcome the drawback that fuzzy classifier was sensitive to noises and outliers, Mamdani fuzzy classifier based on improved chaos immune algorithm was developed, in which bilateral Gaussian membership function parameters were set as constraint conditions and the indexes of fuzzy classification effectiveness and number of correct samples of fuzzy classification as the subgoal of fitness function. Moreover, Iris database was used for simulation experiment, classification, and recognition of acoustic emission signals and interference signals from stope wall rock of underground metal mines. The results showed that Mamdani fuzzy classifier based on improved chaos immune algorithm could effectively improve the prediction accuracy of classification of data sets with noises and outliers and the classification accuracy of acoustic emission signal and interference signal from stope wall rock of underground metal mines was 90.00%. It was obvious that the improved chaos immune Mamdani fuzzy (ICIMF classifier was useful for accurate diagnosis of acoustic emission signal and interference signal from stope wall rock of underground metal mines.

  10. THE METHOD OF ASSESSING ROCK BURSTING HAZARD IN MINING

    Directory of Open Access Journals (Sweden)

    Anna MANOWSKA

    2015-04-01

    Full Text Available The article discusses a concept of forecasting accident risk during longwall extraction in crump-risk conditions. In Polish mines rock burst hazard can be described as high compared to other mines around the world. It's related to increase of depth of longwall field operation, preparation works, including drilling of mine face pavements which leads to systematic deterioration of geological and mining conditions. Depletion of coal is also the reason why mines operate in high mining tremor risk conditions. Mines more and more often operate in decks, where there is large number of edges and remains of older decks. Rocks bursts still remain one of the most dangerous natural hazards and therefore are fundamental prob-lem and have the greatest impact on safety in mining industry. The proposed method for forecasting accidents and loss-es in people and goods can contribute to improvement of work organization methods and mine safety management system.

  11. Continuous lift piers: Damage repair and response during subsidence

    International Nuclear Information System (INIS)

    Drumm, E.C.; Bennett, R.M.; Raaf, D.B.; Daugherty, D.

    1994-01-01

    A series of test foundations damaged during a longwall mining operation were left with permanent tilt, curvature, and substantial cracking. Two of the foundations were releveled using continuous lift piers. The continuous lift piers removed the tilt and curvature and significantly reduced the width of the foundation cracks. Following the releveling of the foundations, an adjacent longwall panel was mined, resulting in additional subsidence, although of smaller magnitude. The response of the releveled foundations was monitored and compared with the response of a footing that was not releveled. Although the continuous pier system does not strengthen the structure and distortion was observed during the second event, the system permitted the deformations to be removed in a few hours

  12. Assessment of surface and subsurface ground disturbance due to underground mining

    International Nuclear Information System (INIS)

    Khair, A.W.

    1994-01-01

    This paper presents highlights of the research carried out at West Virginia University in order to assess surface and subsurface ground disturbance due to longwall mining. Extensive instrumentation and measurements have been made over three longwall mines in northern West Virginia during a three-year period. Various monitoring techniques including full profile borehole extensometer, full profile borehole inclinometers, time domain reflectometry, sonic reflection technique, a unique mechanical grouting method, photographic and visual observations, standard surveying, and water-level measurements were utilized. The paper's emphasis is first on surface ground movement and its impact on integrity of surface ground and structures and second on type and magnitude of subsurface ground movements associated with mine geometry and geology. A subsidence prediction model based on implementation of both mechanisms of ground movement around the excavation and the geologic and geotechnical properties of the rock/coal surrounding the excavation has been developed. 8 refs., 14 figs., 1 tab

  13. Preliminary report on LLNL mine seismicity deployment at the Twentymile Coal Mine

    International Nuclear Information System (INIS)

    Walter, W.R.; Hunter, S.L.; Glenn, L.A.

    1996-01-01

    This report summarizes the preliminary results of a just completed experiment at the Twentymile Coal Mine, operated by the Cyprus Amax Coal Company near Oak Creek, CO. The purpose of the experiment was to obtain local and regional seismic data from roof caves associated with long-wall mining activities and to use this data to help determine the effectiveness with which these events can be discriminated from underground nuclear explosions under a future Comprehensive Test Ban Treaty

  14. The largest US coal acquisition takes shape

    International Nuclear Information System (INIS)

    Carter, R.A.

    1998-01-01

    The midyear purchase of Arco's US coal properties for 1.14 billion dollars gave Arch coal, Inc. (ACI) a string of surface and underground mines stretching from Wyoming's Powder River Basin to the coalfields of central Utah. The transaction created a new entity, Arch Western Resources LLC. The article describes operations at Black Thunder and Coal Creek surface mines and SUFCO, Skyline, Dugout Canyon and West Elk longwall mines. 4 photos

  15. RESEARCH, DEVELOPMENT, AND EXPERIMENTAL TELECOMMUNICATIONS TECHNOLOGY

    Energy Technology Data Exchange (ETDEWEB)

    Zvi H. Meiksin

    2002-07-01

    A temporary installation of Transtek's in-mine communications system in the Lake Lynn mine was used in the mine rescue training programs offered by NIOSH in April and May 2002. We developed and implemented a software program that permits point-to-point data transmission through our in-mine system. We also developed a wireless data transceiver for use in a PLC (programmed logic controller) to remotely control long-wall mining equipment.

  16. Dust-control for thick-seam wall mines.

    CSIR Research Space (South Africa)

    Belle, BK

    2002-02-01

    Full Text Available handler (Source: Long Airdox Australia) Longwall mining represents the most cost-effective way to mine the coal from both the manpower and extractive ratio standpoint. Like any other mining methods, the extraction of coal generates large quantities... pneumoconiosis is being eliminated. However, it is still uncertain whether other health effects, such as chronic bronchitis and obstructive lung disease, will also be well controlled. From the pneumoconiosis point of view, the NSW coal mining industry now...

  17. Cayirhan challenge

    Energy Technology Data Exchange (ETDEWEB)

    Walker, S. [Independent Editorial and Technical Services, Oxford (United Kingdom)

    1999-12-01

    Lignite accounts for around 30% of Turkey's electricity generating capacity, mostly from mines owned by Turkiye Komur Isletmeleri Kurumu (TKI), Alfin-Elbistan Enterprises and Park Holding. Park Teknik, owned by Park Holding and SaarTech, has successfully bid to develop the B and C fields of the Cayirhan deposit in the Beypazari lignite basin. The article describes the development plan and longwall equipment chosen for those seams. 2 photos.

  18. Evaluation of rock burst in deep coal mining by using forensic engineering

    OpenAIRE

    Oraee-Mirzamani, B; Zandi, S

    2015-01-01

    Rock bursts remain an important problem in longwall coal mining. These bursts are due to a sudden and severe failure of rocks from a high stress concentration in deep underground excavations that occur with the instantaneous release of strain energy stored in the rocks. They can potentially cause irrecoverable damage to equipment and personnel, thus accurate rock burst prediction and control is expected to be carried out by the mine design engineer. As a result, this can constitute major chal...

  19. Comparison of Methane Control Methods in Polish and Vietnamese Coal Mines

    OpenAIRE

    Borowski Marek; Kuczera Zbigniew

    2018-01-01

    Methane hazard often occurs in hard coal mines and causes very serious accidents and can be the reason of methane or methane and coal dust explosions. History of coal mining shows that methane released from the rock mass to the longwall area was responsible for numerous mining disasters. The main source of methane are coal deposits because it is autochthonous gas and is closely related with carbonification and forming of coal deposits. Degree of methane saturation in coal deposits depends on ...

  20. Study on the Overlying Strata Movements and Stability Control of the Retained Goaf-side Gateroad

    OpenAIRE

    Zhang, Zhiyi; Shimada, Hideki; Sasaoka, Takashi; Kai, Wen

    2016-01-01

    Recently, Y type gateroad layout, which is based on a retained gob-side gateroad (RGG), is being widely used for the purposes of optimizing ventilation system, increasing coal recovery rate, etc. The RGG, however, suffers several engineering disturbances including roadway excavation and two adjacent longwall panels mining during its whole serving life, which makes the stability control of this kind of roadway is difficult. In order to have a deep insight of this issue, a novel simulation soft...

  1. Releveling and behavior of strap-retrofitted damaged test foundations exposed to mine subsidence

    International Nuclear Information System (INIS)

    Marino, G.G.

    1997-01-01

    Test foundation walls were constructed in an area of planned subsidence. These crawl space-sized block bearing walls were located in the tension zone of a longwall panel. The test walls were 1.2 m (40 ft) long and were vertically loaded on top with soil binds to simulate the weight of a house. As the longwall proceeded past these test foundations, subsidence movements damaged the test structures. These damaged foundations were then structurally and aesthetically repaired by using a steel strap retrofit and applying a cementitious surface coating. The repaired test foundations underwent significant subsequent subsidence as an adjacent longwall was mined beneath. The response of the repaired foundation is summarized in this paper. The steel straps were also used to relevel another set of the test foundations after they were tilted and damaged by subsidence. First, the straps were applied to the block bearing walls, and then wall jacks were used to lift the upper portion of the walls to a level position. This releveling procedure is outlined with the results

  2. Determination of Destress Blasting Effectiveness Using Seismic Source Parameters

    Science.gov (United States)

    Wojtecki, Łukasz; Mendecki, Maciej J.; Zuberek, Wacaław M.

    2017-12-01

    Underground mining of coal seams in the Upper Silesian Coal Basin is currently performed under difficult geological and mining conditions. The mining depth, dislocations (faults and folds) and mining remnants are responsible for rockburst hazard in the highest degree. This hazard can be minimized by using active rockburst prevention, where destress blastings play an important role. Destress blastings in coal seams aim to destress the local stress concentrations. These blastings are usually performed from the longwall face to decrease the stress level ahead of the longwall. An accurate estimation of active rockburst prevention effectiveness is important during mining under disadvantageous geological and mining conditions, which affect the risk of rockburst. Seismic source parameters characterize the focus of tremor, which may be useful in estimating the destress blasting effects. Investigated destress blastings were performed in coal seam no. 507 during its longwall mining in one of the coal mines in the Upper Silesian Coal Basin under difficult geological and mining conditions. The seismic source parameters of the provoked tremors were calculated. The presented preliminary investigations enable a rapid estimation of the destress blasting effectiveness using seismic source parameters, but further analysis in other geological and mining conditions with other blasting parameters is required.

  3. Technology and feasibility of potential underground thick seam mining methods

    Energy Technology Data Exchange (ETDEWEB)

    Bruce Hebblewhite; Y. Cai; A. Simonis [University of New South Wales, NSW (Australia)

    2002-05-01

    The objectives of this current research project were to conduct a detailed investigation into the overall mining system and technology components of the systems listed above, with emphasis on three methods: single pass longwall (SPL); multi-pass longwall (MPL); and hydraulic mining (HM). The investigations were to include: ability to up-scale production levels, productivity and hence the economic viability above current best practice for each method; identification of the detailed equipment requirements necessary to achieve the above objective. Geotechnical design studies on critical issues identified from previous ACARP project; critical review, economic evaluation and risk assessment of methods under review. However, during this project, the project team became aware of the significant advances being made in China with a modified version of the soutirage method, known as Longwall Top Coal Caving (LTCC) which had been omitted from the project. This method was identified as having not only the potential to be an alternative to soutirage, but as a top priority thick seam method, in comparison with all other options. It has been concluded that if this method to be considered in this country, there are still a number of issues that must be resolved. The problem of coal/goaf interface detection is of particular importance, if levels of dilution are to be reduced. In addition, environmental issues such as dust suppression and spontaneous combustion still need to be further examined.

  4. Study of the ‘lifeline’ as the measure allowing for safe self-rescue of miners in conditions of lack of visibility caused by underground fire

    Science.gov (United States)

    Badura, Henryk; Grodzicka, Aneta; Musioł, Dariusz

    2017-11-01

    The article presents statistical data regarding the evacuation of miners affected by underground fire hazards. The data indicates that the hazard remains considerable. Due to the increasing lengths of escape routes, measures should be introduced in the longwall regions, which shall improve the safe evacuation of miners, especially in conditions of highly limited visibility or the lack thereof. Within the research project No. 12, entitled: ‘The development of orientation systems and systems for signalling the direction of crew withdrawal for escape routes in longwall gates’, which is a part of the Strategic Research Project entitled ‘The improvement of work safety in mines’ financed by the National Centre for Research and Development, a ‘lifeline’ was designed - that is, a measure that is very effective in the evacuation of staff. Subsequently, tests of time of passage were conducted in the ‘Krupiński’ coal mine in conditions of lack of visibility. The tests have confirmed the suitability of the ‘lifeline’ as the measure used for orientation towards the correct direction of evacuation, which increases the pace and the confidence while travelling through the escape route. The mean speed of passage through the heading with an upwards inclination of 11° was 22 m/min, while in case of a nearly horizontal longwall gate, it was 39 m/min.

  5. Economic assessment of utilizing protective properties of level coal seams

    Energy Technology Data Exchange (ETDEWEB)

    Bakhtin, A.F.; Batmanov, Yu.K.; Gainutdinov, I.A.

    1982-12-01

    Increasing mining depth negatively influences mining efficiency and safety. At depths to 600 m 10% of coal comes from seams prone to rock bursts. At depths exceeding 600 m proportion of coal from seams prone to rock bursts increases to 40%. Investigations carried out in Ukrainian coal mines show that coal losses (due to rock burst hazard) in level seams mined by a longwall system amount to 4.6 Mt per year. Cost of rock burst prevention and repairs after rock bursts amounts to 12 million rubles per year. About 68% of coal from level coal seams comes from long coal pillars mined by a longwall system. In level coal seams prone to rock bursts this proportion is 40% lower (proportion of longwall mining is reduced due to increased rock burst hazards). Only 10% of coal seams prone to rock bursts are mined using a system of stress relaxation by cutting another overlying or underlying coal seam (utilizing protective properties of a coal seam). A method for economic analysis of protective properties of coal seams in seam groups is described. Using the method the optimum order of mining coal seams in a seam group is determined. Examples of the method's use are analyzed. (3 refs.) (In Russian)

  6. Assessment of mining horizontal seams at depth considering strata stress factor

    Energy Technology Data Exchange (ETDEWEB)

    Bakhtin, A.F.

    1983-04-01

    This paper discusses systems of mining level coal seams at large depths in the light of increasing mining depth in the Donbass, where about 50% of mined coal comes from depths exceeding 600 m. Mining systems used in underground mining in the Donbass are evaluated: 77.4% of production is from long pillar mining, 8.6% from longwall mining and 14% from combined systems. Seventeen variants of long pillar mining and longwall mining schemes used in the Donbass are compared. Effects of strata movement and strata control in mine roadways on mining cost are analyzed. A mathematical model is used for comparative evaluations of mining cost at large depths. Analyses show that long pillar mining combined with repeated use of gate roads is associated with considerable cost of support repair and support replacement. Recommendations on support systems suitable for strata control in mine roadways influenced by longwall mining are made. When roof subsidence does not exceed 500 mm, use of three-element yielding arched supports is recommended. In mine roadways with strata subsidence from 500 to 1200 mm, yielding arched supports consisting of five elements should be used. When forecast roof subsidence exceeds 1200 mm, additional support systems (such as friction props or hydraulic props) should be used. (6 refs.) (In Russian)

  7. The influence of subsidence attributable to coal mining on the environment, development and restoration: some examples from western Europe and South Africa

    Energy Technology Data Exchange (ETDEWEB)

    Bell, F.G.; Genske, D.D. [University of Natal, Durban (South Africa). Dept. of Geology & Applied Geology

    2001-02-01

    One of the consequences of coal mining is subsidence, and it is associated with past and present mine workings. Indeed, old abandoned coal mines worked by the room-and-pillar method, which occur at shallow depth, often present a potential hazard as pillars collapse or voids migrate to the surface. Frequently, the situation is compounded by the fact that such workings are unrecorded. Subsidence prediction in such cases is impossible. In longwall mining, the total extraction of panels takes place, the working face being supported, while support is removed from behind the working face allowing the roof to collapse. Subsidence consequent on longwall mining can be regarded as more or less contemporaneous with mining and is normally predictable. This means that it is possible to develop an area after subsidence due to longwall mining has occurred or to incorporate features into the design of buildings and structures that will accommodate ground movements generated by subsidence. The nature of subsidence can be affected by discontinuities in the surface strata or the presence of superficial deposits. Of course, subsidence can adversely affect existing buildings and structures which do not incorporate special design features. In severe cases of subsidence damage, buildings may have to be demolished. Important buildings may be restored. Another problem associated with subsidence is flooding due to notable lowering of the ground surface. Examples of such problems and solutions are highlighted by the examples given.

  8. Direct shear tests on cemented paste backfill–rock wall and cemented paste backfill–backfill interfaces

    Directory of Open Access Journals (Sweden)

    Nabassé J.F. Koupouli

    2016-08-01

    Full Text Available This paper presents the results of the shear strength (frictional strength of cemented paste backfill-cemented paste backfill (CPB-CPB and cemented paste backfill–rock wall (CPB-rock interfaces. The frictional behaviors of these interfaces were assessed for the short-term curing times (3 d and 7 d using a direct shear apparatus RDS-200 from GCTS (Geotechnical Consulting & Testing Systems. The shear (friction tests were performed at three different constant normal stress levels on flat and smooth interfaces. These tests aimed at understanding the mobilized shear strength at the CPB-rock and CPB-CPB interfaces during and/or after open stope filling (no exposed face. The applied normal stress levels were varied in a range corresponding to the usually measured in-situ horizontal pressures (longitudinal or transverse developed within paste-filled stopes (uniaxial compressive strength, σc ≤ 150 kPa. Results show that the mobilized shear strength is higher at the CPB-CPB interface than that at the CPB-rock interface. Also, the perfect elastoplastic behaviors observed for the CPB-rock interfaces were not observed for the CPB-CPB interfaces with low cement content which exhibits a strain-hardening behavior. These results are useful to estimate or validate numerical model for pressures determination in cemented backfill stope at short term. The tests were performed on real backfill and granite. The results may help understanding the mechanical behavior of the cemented paste backfill in general and, in particular, analyzing the shear strength at backfill–backfill and backfill-rock interfaces.

  9. Optimal location of emergency stations in underground mine networks using a multiobjective mathematical model.

    Science.gov (United States)

    Lotfian, Reza; Najafi, Mehdi

    2018-02-26

    Background Every year, many mining accidents occur in underground mines all over the world resulting in the death and maiming of many miners and heavy financial losses to mining companies. Underground mining accounts for an increasing share of these events due to their special circumstances and the risks of working therein. Thus, the optimal location of emergency stations within the network of an underground mine in order to provide medical first aid and transport injured people at the right time, plays an essential role in reducing deaths and disabilities caused by accidents Objective The main objective of this study is to determine the location of emergency stations (ES) within the network of an underground coal mine in order to minimize the outreach time for the injured. Methods A three-objective mathematical model is presented for placement of ES facility location selection and allocation of facilities to the injured in various stopes. Results Taking into account the radius of influence for each ES, the proposed model is capable to reduce the maximum time for provision of emergency services in the event of accident for each stope. In addition, the coverage or lack of coverage of each stope by any of the emergency facility is determined by means of Floyd-Warshall algorithm and graph. To solve the problem, a global criterion method using GAMS software is used to evaluate the accuracy and efficiency of the model. Conclusions 7 locations were selected from among 46 candidates for the establishment of emergency facilities in Tabas underground coal mine. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  10. New developments in uranium mining in India

    International Nuclear Information System (INIS)

    Puri, R.C.

    1993-01-01

    Uranium mining is so far restricted to underground mines only. Uranium mining is similar to other non-coal (metalliferous) mining. Mode of entries has been adits, inclines and vertical shafts. Decline have been constructed at Narwapahar and Turamdih. Access decline (7 deg) at Narwapahar has been driven to about 900 m length and reached depth of about 100 m. Stoping methods are mainly with filling, open stopes supported with adequate pillars with or without post filling to prevent surface subsidence are also being adopted. Appreciable degree of mechanization has been adopted in Jaduguda mines however, Narwapahar mine has been made highly mechanized. Face mechanization in the present operations is by way of air leg mounted jack hammers and stope wagons for drilling and small capacity (upto 1 cu. yd) rail mounted/trackless loaders for loading. Alimak raise climber has been used for raising work. For horizontal transport in mines, Hunselet diesel locomotives (4 tonne size) with Granby car, 3.5 tonne capacity, are being used, vertical transport is by means of drum winders and tower mounted friction winders. At Narwapahar mine twin boom drill jumobs, LHDs-1.78 m 3 and 2.8 m 3 capacity, PLDTs-15 tonner and 23 tonner capacity and relevant service equipment like passenger carriers, supply trucks, service cum lube truck, motor grader, etc. are being used. These rubber tyrred trackless equipment enter the mine directly from the surface through the service/access decline entry. These new developments in mining are detailed hereinafter. (author). 11 figs., 4 photos

  11. Numerical Study on 4-1 Coal Seam of Xiaoming Mine in Ascending Mining

    Directory of Open Access Journals (Sweden)

    Lan Tianwei

    2015-01-01

    Full Text Available Coal seams ascending mining technology is very significant, since it influences the safety production and the liberation of dull coal, speeds up the construction of energy, improves the stability of stope, and reduces or avoids deep hard rock mining induced mine disaster. Combined with the Xiaoming ascending mining mine 4-1, by numerical calculation, the paper analyses ascending mining 4-1 factors, determines the feasibility of ascending mining 4-1 coalbed, and proposes roadway layout program about working face, which has broad economic and social benefits.

  12. POLICIES AND PRACTICIES REGARDING THE PROTECTION OF FLORA AND FAUNA IN EUROPE AND IN ROMANIA

    Directory of Open Access Journals (Sweden)

    Codruta Suciu

    2016-11-01

    Full Text Available Att he beginning of the ‘90’s the Europeanflora and fauna decreased drastic due to the negative effects of pollution, urban areas sprawl, wild territories fragmentation and the antropic impact ofenvirnoment. Therefore, there were adopted certain measures, directives  for birds and habitas protection. Today,Europe has the largest interconnected network of protected areas from the worldand this led to slowing or even stoping degradation of some affected territories.In some cases there were noticed even habitats recovery. After Romania’s accession to European Union and after adoptinghabitats and birds directives was noticed a significant increase of protectedareas.

  13. Shear zones between rock units with no relative movement

    DEFF Research Database (Denmark)

    Koyi, H.; Schmeling, H.; Burchardt, S.

    2012-01-01

    Shear zones are normally viewed as relatively narrow deformation zones that accommodate relative displacement between two "blocks" that have moved past each other in opposite directions. This study reports localized zones of shear between adjacent blocks that have not moved past each other...... magma body (stoping). From the fluid dynamics point of view these shear zones can be regarded as the low Reynolds number deformation zones within the wake of a body moving through a viscous medium. While compact (aspect ratio 1:1:1) moving bodies generate axial symmetric (cone like) shear zones...

  14. Shear zones between rock units with no relative movement

    DEFF Research Database (Denmark)

    Koyi, Hemin; Schmeling, Harro; Burchardt, Steffi

    2013-01-01

    Shear zones are normally viewed as relatively narrow deformation zones that accommodate relative displacement between two "blocks" that have moved past each other in opposite directions. This study reports localized zones of shear between adjacent blocks that have not moved past each other...... a partially molten magma body (stoping). From the fluid dynamics perspective these shear zones can be regarded as low Reynolds number deformation zones within the wake of a body moving through a viscous medium. While compact moving bodies (aspect ratio 1:1:1) generate axial symmetric (cone like) shear zones...

  15. Relationship between ERR and seismic energy release for different geotechnical areas.

    CSIR Research Space (South Africa)

    Spottiswoode, S

    2000-04-01

    Full Text Available -induced seismicity. This control measure has been exercised through limiting the average Energy Release Rate (ERR) to some figure, typically 20 or 30 MJ/m2. Mines have responded by leaving large areas of reef as regional stability pillars. It has been found... of the effect of backfill requires a study of in-stope measurements. Further research in this area will most likely improve correlations between observed and modelled seismicity. This will be the main thrust of the GAP722 project starting in April 2000...

  16. De la ética católica a la ética de la pobreza: Hacia una tesis sobre las ideas y creencias religiosas como factor de rezago socioeconómico en la población mexicana de los Estados Unidos

    Directory of Open Access Journals (Sweden)

    Rafael Arriaga Martínez

    1996-01-01

    Full Text Available This article pretends to found a thesis which major preposition postulates the possibility to determine the influence in the ideas and religious beliefs in the economic behavior of Mexican residents in the United States. As a key concept in this discussion, in this case, religion is defined according to one ofthe corollarles of Max Weber' s vision aboilt religion: an ethic vehicJe capable of stoping or stimulating the social ascent of social groups. Therefore, around this two statements we concatenated a wide pan of theorical, conceptual and methodological basis of this work.

  17. Volumetric analysis of rock mass instability around haulage drifts in underground mines

    Directory of Open Access Journals (Sweden)

    Shahé Shnorhokian

    2018-02-01

    Full Text Available Haulage networks are vital to underground mining operations as they constitute the arteries through which blasted ore is transported to surface. In the sublevel stoping method and its variations, haulage drifts are excavated in advance near the ore block that will be mined out. Numerical modeling is a technique that is frequently employed to assess the redistribution of mining-induced stresses, and to compare the impact of different stope sequence scenarios on haulage network stability. In this study, typical geological settings in the Canadian Shield were replicated in a numerical model with a steeply-dipping tabular orebody striking EW. All other formations trended in the same direction except for two dykes on either side of the orebody with a WNW–ESE strike. Rock mass properties and in situ stress measurements from a case study mine were used to calibrate the model. Drifts and crosscuts were excavated in the footwall and two stope sequence scenarios – a diminishing pillar and a center-out one – were implemented in 24 mining stages. A combined volumetric-numerical analysis was conducted for two active levels by comparing the extent of unstable rock mass at each stage using shear, compressive, and tensile instability criteria. Comparisons were made between the orebody and the host rock, between the footwall and hanging wall, and between the two stope sequence scenarios. It was determined that in general, the center-out option provided a larger volume of instability with the shear criterion when compared to the diminishing pillar one (625,477 m3 compared to 586,774 m3 in the orebody; 588 m3 compared to 403 m3 in the host rock. However, the reverse was true for tensile (134,298 m3 compared to 128,834 m3 in the orebody; 91,347 m3 compared to 67,655 m3 in the host rock instability where the diminishing pillar option had the more voluminous share.

  18. Experimental validation of tip over stability of a tracked mobile manipulator

    CSIR Research Space (South Africa)

    Dube, C

    2013-09-01

    Full Text Available hanging wall (roof has to be inspected for loose rock that could potentially fall and cause injuries. This inspection is typically performed by a miner who is in constant danger while performing the task. The aim of the MSP project is to remove the miner... form danger by sending in a robot to perform the post-blast inspection. The platform will explore and create a map of the mine stope and it’s manipulator will then perform inspections of the hanging wall. An iRobot PackBot510 robot is currently being...

  19. Numerical Study on 4-1 Coal Seam of Xiaoming Mine in Ascending Mining

    Science.gov (United States)

    Tianwei, Lan; Hongwei, Zhang; Sheng, Li; Weihua, Song; Batugin, A. C.; Guoshui, Tang

    2015-01-01

    Coal seams ascending mining technology is very significant, since it influences the safety production and the liberation of dull coal, speeds up the construction of energy, improves the stability of stope, and reduces or avoids deep hard rock mining induced mine disaster. Combined with the Xiaoming ascending mining mine 4-1, by numerical calculation, the paper analyses ascending mining 4-1 factors, determines the feasibility of ascending mining 4-1 coalbed, and proposes roadway layout program about working face, which has broad economic and social benefits. PMID:25866840

  20. Cluster analysis and relative relocation of mining-induced seismicity using HAMNET data

    Science.gov (United States)

    Wehling-Benatelli, S.; Becker, D.; Bischoff, M.; Friederich, W.; Meier, T.

    2012-04-01

    Longwall mining activity in the Ruhr-coal mining district leads to mining-induced seismicity. For detailed studies seismicity of the single longwall panel S 109 beneath Hamm-Herringen in the eastern Ruhr area was monitored between June 2006 and July 2007. More than 7000 seismic events with magnitudes -1.7 ≤ ML ≤ 2.0 are localized in this period. 70% of the events occur in the vicinity of the moving longwall face. Moreover, the seismicity pattern shows spatial clustering of events in distances up to 500 m from the panel which is related to remnant pillars of old workings and tectonic features. Two sources with common location and rock failure mechanism are expected to show identical waveforms. Hence, similar waveforms suggest similarity of source properties. Waveform similarity can be quantified by cross-correlation. Similarity matrices have been established and build the basis of a cluster analysis presented here. We compare two approaches for cluster definition: a single-linkage approach and excerpting clusters by visual inspection of the sorted similarity matrices. Clusters are found as areas of high inter-event similarity in the depicted matrix. In contrast, the single-linkage approach assigns an event to the cluster if the similarity threshold v sl = 0.9 is exceeded to at least one other member. This method is more restrictive and, in general, leads to clusters with less members than visual inspection. Both methods exhibit clusters which show the same properties. The largest clusters are built by low-magnitude events (around ML ≈-0.6) directly at the longwall face at the mining level. Other clusters include events with magnitudes as large as ML,max = 1.8. Their locations tend to lie above or below the mining level in load-bearing sandstone layers. Mining accompanying events show face-parallel near vertical fault planes whereas more distant clusters have typical solutions of remnant pillar failure with a medium dip angle. Relative relocation of the events

  1. Coal Mine Accidents in Bangladesh: Its Causes and Remedial Measures

    Directory of Open Access Journals (Sweden)

    MD. MINHAJ UDDIN MONIR

    2012-12-01

    Full Text Available Barapukuria coal mine (BCM is located at Dinajpur district, NW Bangladesh. Total area is about 6.68 km2 and coal was encountered at a depth ranging between 118 and 509 m. Six major coal seams (seam I to seam VI were identified at BCM, of which, thickest one is the seam-VI (~36 m. The estimated coal reserves is about 390 million tons and of this, nearly 64 million tons of coal is extractable. The annual production of coal is about 1 million ton. In this study several parameters were used to explore minimization of accidents and improvement of coal production in BCM. Considering the geological, hydrological and other technical parameters, longwall mining method is applied for extraction of coal. Longwall retreating mining method is also applied for extraction of coal from single face with the operational area protected by self-advancing hydraulic powered roof support (HPRS system. These supports are moved forward causing the roof behind them to form an extensive abandoned area named goaf, which may lead to collapse with air blast. Coal in BCM is extracted from seam VI, using a multislice Longwall top coal caving method. Average ventilated air composition is ~20.94% oxygen, ~79.00% nitrogen, ~0.04% carbon monoxide, and minor water steam with huge dust. Production of coal was completed from 12 Longwall faces of 1st slice from seam VI. During production period several accidents and troubles within BCM have occurred. Poisonous gases such as carbon monoxide were detected during/after development of 1110 Longwall face, which increases up to 6000 ppm, therefore, sealed-off the face with mining equipments. During the development of belt gate roadway of 1101 Longwall face, maximum temperature and humidity increases up to 37 oC and 100%, respectively. Miners of BCM experienced some difficulties to work in that adverse environment. Air return roadway temperature was always 40 to 41oC in 1101 Longwall face during production period, faces temperature 46o

  2. Research of Cemented Paste Backfill in Offshore Environments

    Science.gov (United States)

    Wang, Kun; Yang, Peng; Lyu, Wensheng; Lin, Zhixiang

    2018-01-01

    To promote comprehensive utilization of mine waste tailings and control ground pressure, filling mine stopes with cement paste backfill (CPB) is becoming the most widely used and applicable method in contemporary underground mining. However, many urgent new problems have arisen during the exploitation in offshore mines owing to the complex geohydrology conditions. A series of rheological, settling and mechanical tests were carried out to study the influences of bittern ions on CPB properties in offshore mining. The results showed that: (1) the bittern ion compositions and concentrations of backfill water sampled in mine filling station were similar to seawater. Backfill water mixed CPB slurry with its higher viscosity coefficient was adverse to pipeline gravity transporting; (2) Bleeding rate of backfill water mixed slurry was lower than that prepared with tap water at each cement-tailings ratio; (3) The UCS values of backfill water mixed samples were higher at early curing ages (3d, 7d) and then became lower after longer curing time at 14d and 28d. Therefore, for mine production practice, the offshore environments can have adverse effects on the pipeline gravity transporting and have positive effects on stope dewatering process and early-age strength growth.

  3. Determination of radon flux rates in a uranium mine (Cluff Lake, Saskatchewan)

    International Nuclear Information System (INIS)

    1989-12-01

    The Atomic Energy Control Board contracted SENES Consultants Limited to design and implement a field program at Amok Limited's Cluff Lake uranium mine, with the overall objective of obtaining reliable radon flux data applicable for use in the VENTRAD computer model. The VENTRAD model was developed to model underground mine ventilation systems. To avoid the uncertainties inherent in localized flux measurements made on small surfaces, radon flux measurements were determined through measurement of incremental changes in the concentration of radon between the incoming and outgoing air in selected areas of the underground workings. The locations were selected throughout the mine in both ore and sterile rock. Average radon flux rates measured during three field campaigns were as follows: sterile rock decline 4 pCi/m 2 .second; sterile rock mainway 25 pCi/m 2 .second; worked-out stope 100 pCi/m 2 .second; active work stope 240 pCi/m 2 .second; and work face 14,000 pCi/m 2 .second. Data collected during the three field programs were used to validate the VENTRAD computer model. The results of the validation exercise suggest close agreement between predicted and measured air flow rates and radon concentrations were overestimated for areas immediately impacted by auxiliary ventilation fans and ore transfer mill holes which connect the ore extraction and haulage levels of the mine

  4. Temporal and spatial changes of land use and landscape in a coal mining area in Xilingol grassland

    Science.gov (United States)

    Guan, Chunzhu; Zhang, Baolin; Li, Jiannan; Zhao, Junling

    2017-01-01

    Coal mining, particularly surface mining, inevitably disturbs land. According to Landsat images acquired over Xilingol grassland in 2005, 2009 and 2015, land uses were divided into seven classes, i. e., open stope, stripping area, waste-dump area, mine industrial area, farmland, urban area and the original landscape (grassland), using supervised classification and human-computer interactive interpretation. The overall classification accuracies were 97.72 %, 98.43 % and 96.73 %, respectively; the Kappa coefficients were 0.95, 0.97 and 0.95, respectively. Analysis on LUCC (Land Use and Cover Change) showed that surface coal mining disturbed grassland ecosystem: grassland decreased by 8661.15 hm2 in 2005-2015. The area and proportion of mining operation areas (open stope, stripping area, waste-dump area, mine industrial field) increased, but those of grassland decreased continuously. Transfer matrix of land use changes showed that waste-dump had the largest impacts in mining disturbance, and that effective reclamation of waste-dump areas would mitigate eco-environment destruction, as would be of great significance to protect fragile grassland eco-system. Six landscape index showed that landscape fragmentation increased, and the influences of human activity on landscape was mainly reflected in the expansion of mining area and urban area. Remote sensing monitoring of coal surface mining in grassland would accurately demonstrate the dynamics and trend of LUCC, providing scientific supports for ecological reconstruction in surface mining area.

  5. Attracting men to vasectomy.

    Science.gov (United States)

    Finger, W R

    1998-01-01

    There is far less information available for men about vasectomy than there is available for women about comparable contraceptive services. Also, men do not have medical check-ups on a regular basis, and therefore have less contact with medical practitioners during which vasectomy could otherwise be discussed. Vasectomy needs to be promoted in order for men to learn about and accept it as their contraceptive method of choice. To that end, Marie Stopes International (MSI) launches a vasectomy promotion campaign annually which includes advertising in local newspapers and upon billboards at football stadiums. The campaigns use light-hearted and bold ideas, with some shock value. This approach helps to relax men who otherwise tend to be wary of both the surgical procedure and subsequent consequences of vasectomy. Prevailing social norms should, however, guide the content of promotional campaigns. The UK is one of only a few countries in the world where about the same proportions of men and women use sterilization; 16% of men and 15% of women have been sterilized. A MSI campaign in the UK which began during fall 1997 prompted an increase in the number of inquiries about vasectomy at the Marie Stopes Vasectomy Clinic. Promotional campaigns in developing countries have also been successful. It is also important that campaigns be put in the larger context of promoting all contraceptive methods.

  6. Development of mining at Jaduguda

    International Nuclear Information System (INIS)

    Bhasin, J.L.

    1991-01-01

    The paper deals with the development of mining and other infrastructural activities of the underground mine at Jaduguda. In the beginning open and shrinkage methods were used but gradually changed to Cut and Fill method, the fill being the deslimed mill tailings. This method gives much better recovery and provides adequate support to the worked out areas. The main entry to the mine is via a vertical shaft, 640 meters deep. The winders for ore hoisting and the services are installed on top of the concrete tower constructed above the shaft. As the winders are the life line of the mine, a high standard of maintenance is maintained. As the mine is located at the foot hill, there is a fair amount of seepage water. The seepage and the water from the fill is pumped to surface in stages. The sumps at various levels are designed to provide storage capacity. From time to time, the technological improvements in the various mining operations are brought about. The drilling of uppers by stope wagons, use of tyre mounted loaders in the stopes, use of ammonium nitrate for blasting purposes, the use of full column grout bolts are some examples. Studies are also conducted in the ground control in underground. Constant efforts are made to improve the support system. The training courses are regularly arranged for workers to update their skills. As the job in underground is hazardous, the workers are trained in the correct and safe methods of doing the various jobs. (author). 10 figs

  7. Hydrologic conditions and water-quality conditions following underground coal mining in the North Fork of the Right Fork of Miller Creek drainage basin, Carbon and Emery Counties, Utah, 2004-2005

    Science.gov (United States)

    Wilkowske, C.D.; Cillessen, J.L.; Brinton, P.N.

    2007-01-01

    In 2004 and 2005, the U.S. Geological Survey, in cooperation with the Bureau of Land Management, reassessed the hydrologic system in and around the drainage basin of the North Fork of the Right Fork (NFRF) of Miller Creek, in Carbon and Emery Counties, Utah. The reassessment occurred 13 years after cessation of underground coal mining that was performed beneath private land at shallow depths (30 to 880 feet) beneath the NFRF of Miller Creek. This study is a follow-up to a previous USGS study of the effects of underground coal mining on the hydrologic system in the area from 1988 to 1992. The previous study concluded that mining related subsidence had impacted the hydrologic system through the loss of streamflow over reaches of the perennial portion of the stream, and through a significant increase in dissolved solids in the stream. The previous study also reported that no substantial differences in spring-water quality resulted from longwall mining, and that no clear relationship between mining subsidence and spring discharge existed.During the summers of 2004 and 2005, the USGS measured discharge and collected water-quality samples from springs and surface water at various locations in the NFRF of Miller Creek drainage basin, and maintained a streamflow-gaging station in the NFRF of Miller Creek. This study also utilized data collected by Cyprus–Plateau Mining Corporation from 1992 through 2001.Of thirteen monitored springs, five have discharge levels that have not returned to those observed prior to August 1988, which is when longwall coal mining began beneath the NFRF of Miller Creek. Discharge at two of these five springs appears to fluctuate with wet and dry cycles and is currently low due to a drought that occurred from 1999–2004. Discharge at two other of the five springs did not increase with increased precipitation during the mid-1990s, as was observed at other monitored springs. This suggests that flowpaths to these springs may have been altered by

  8. Bribery and Its Ethical Implications for Aid Workers in the Developing World.

    Science.gov (United States)

    Remer, J Scott

    2017-02-01

    Bribery is a complicated, multi-dimensional issue. Upon first glance, most westerners would immediately condemn it as an underhanded, unfair means of gaining an advantage in a competitive or legal situation, and so it is in virtually every case in the westernized world. However, the issue becomes much more complicated in the international context, particularly in developing nations, where giving and accepting bribes is often normal and expected. This paper serves to inform ethical decision-making in situations where the "right choice" is unclear with regards to bribery, primarily for individuals performing aid work in foreign countries with corrupt officials and police officers. In such contexts, a simple offering of food, money, or a small trinket may make the difference between a person being able to accomplish meaningful, life-changing work for the local populace or having that work significantly slowed at best and being thrown out of the country, robbed, or imprisoned in worse cases. The larger scale bribery issues in international business and the laws pertaining to them are also discussed.

  9. Proficiency deficiency: mastery of fundamental movement skills and skill components in overweight and obese children.

    Science.gov (United States)

    Cliff, Dylan P; Okely, Anthony D; Morgan, Philip J; Jones, Rachel A; Steele, Julie R; Baur, Louise A

    2012-05-01

    The purpose of this observational study was to compare the mastery of 12 fundamental movement skills (FMS) and skill components between a treatment-seeking sample of overweight/obese children and a reference sample from the United States. Mastery of six locomotor and six object-control skills (24 components in each subdomain) were video-assessed by one assessor using the test of gross motor development-2 (TGMD-2). The 153 overweight/obese children (mean ± s.d. age = 8.3 ± 1.1 years, BMI z-score = 2.78 ± 0.69, 58% girls, 77% obese) were categorized into age groups (for the underhand roll and strike: 7-8 years and 9-10 years; all other FMS: 6-7 years and 8-10 years) and mastery prevalence rates were compared with representative US data (N = 876) using χ(2) analysis. For all 12 skills in all age groups, the prevalence of mastery was lower among overweight/obese children compared with the reference sample (all P movement patterns that could be targeted for improvement include positioning of the body and feet, the control or release of an object at an optimal position, and better use of the arms to maintain effective force production during the performance of FMS. Physical activity programs designed for overweight and obese children may need to address deficiencies in FMS proficiency to foster the movement capabilities required for participation in health-enhancing physical activity.

  10. Study of otoacoustic emissions in workers of various professional groups of the coal industry

    Directory of Open Access Journals (Sweden)

    Shydlovska T.A.

    2015-09-01

    Full Text Available Noise influence takes one of the leading roles in the development of sensorineural hearing loss (SHL. At the same time professional deafness steadily occupies the 5th place in the structure of occupational diseases in Ukraine over the past few years. Of special importance is the problem of pre-clinical and early diagnosis of occupational hearing deterioration, in sense of timely prophylactic and rehabilitation measures in “risk group” workers. The objective research methods play an important role in the diagnosis of auditory analyzer state. Many scientific studies have shown the diagnostic effectiveness of method of otoacoustic emissions recording in the early diagnosis of lesions of receptor part of auditory analyzer. It is known that SHL of noise genesis largely affects the receptor part of the auditory analyzer, for which the OAE method has great practical diagnostic significance. Objective: to study informativity indicators of otoacoustic emission for the diagnosis of sensorineural hearing loss in various occupational groups of coal workers in Ukrainian mines. Materials and Methods: Auditory function of 87 workers of the coal industry (drifters, miners and longwall miners with different levels of industrial noise and hygienic conditions in their workplaces was: 28 studied drifters (group 1, 25 miners (group 2 and 34 longwall miners (group 3. Work experience in noise in these groups was 17,9±1,0; 23,1±1,0 and 22,2±2,0 accordingly. Noise ratio in drifters was 93,6±4,9 dBA, in miners – 92,9±5,5 dBA and in longwall miners – 86,5±6,04 dBA accordingly, while the maximum permitted level is 80 dBA. The research was conducted on the analyzing system "Eclipse" "Interacoustics" (Denmark. All patients underwent registratiov of the caused OAE at frequency distortion product (DPOAE at frequencies 1-6 kHz. The results were rated using variation statistics Student's test. Results: The most prominent violation of the receptor part of the

  11. Grade Distribution Modeling within the Bauxite Seams of the Wachangping Mine, China, Using a Multi-Step Interpolation Algorithm

    Directory of Open Access Journals (Sweden)

    Shaofeng Wang

    2017-05-01

    Full Text Available Mineral reserve estimation and mining design depend on a precise modeling of the mineralized deposit. A multi-step interpolation algorithm, including 1D biharmonic spline estimator for interpolating floor altitudes, 2D nearest neighbor, linear, natural neighbor, cubic, biharmonic spline, inverse distance weighted, simple kriging, and ordinary kriging interpolations for grade distribution on the two vertical sections at roadways, and 3D linear interpolation for grade distribution between sections, was proposed to build a 3D grade distribution model of the mineralized seam in a longwall mining panel with a U-shaped layout having two roadways at both sides. Compared to field data from exploratory boreholes, this multi-step interpolation using a natural neighbor method shows an optimal stability and a minimal difference between interpolation and field data. Using this method, the 97,576 m3 of bauxite, in which the mass fraction of Al2O3 (Wa and the mass ratio of Al2O3 to SiO2 (Wa/s are 61.68% and 27.72, respectively, was delimited from the 189,260 m3 mineralized deposit in the 1102 longwall mining panel in the Wachangping mine, Southwest China. The mean absolute errors, the root mean squared errors and the relative standard deviations of errors between interpolated data and exploratory grade data at six boreholes are 2.544, 2.674, and 32.37% of Wa; and 1.761, 1.974, and 67.37% of Wa/s, respectively. The proposed method can be used for characterizing the grade distribution in a mineralized seam between two roadways at both sides of a longwall mining panel.

  12. Effects of torpedo blasting on rockburst prevention during deep coal seam mining in the Upper Silesian Coal Basin

    Directory of Open Access Journals (Sweden)

    Ł. Wojtecki

    2017-08-01

    Full Text Available In the Upper Silesian Coal Basin (USCB, coal seams are exploited under progressively more difficult geological and mining conditions (greater depth, higher horizontal stress, more frequent occurrence of competent rock layers, etc.. Mining depth, dislocations and mining remnants in coal seams are the most important factors responsible for the occurrence of rockburst hazards. Longwall mining next to the mining edges of neighbouring coal seams is particularly disadvantageous. The levels of rockburst hazards are minimised via the use of rockburst prevention methods. One active prevention method is torpedo blasting in roof rocks. Torpedo blastings are performed in order to decrease local stress concentrations in rock masses and to fracture the roof rocks to prevent or minimise the impact of high-energy tremors on excavations. The estimation of the effectiveness of torpedo blasting is particularly important when mining is under difficult geological and mining conditions. Torpedo blasting is the main form of active rockburst prevention in the assigned colliery in the Polish part of the USCB. The effectiveness of blasting can be estimated using the seismic effect method, in which the seismic monitoring data and the mass of explosives are taken into consideration. The seismic effect method was developed in the Czech Republic and is always being used in collieries in the Czech part of the coal basin. Now, this method has been widely adopted for our selected colliery in the Polish part of the coal basin. The effectiveness of torpedo blastings in the faces and galleries of the assigned longwall in coal seam 506 has been estimated. The results show that the effectiveness of torpedo blastings for this longwall was significant in light of the seismic effect method, which corresponds to the in situ observations. The seismic effect method is regularly applied to estimating the blasting effectiveness in the selected colliery.

  13. Analysis of Overlying Strata Movement and Behaviors in Caving and Solid Backfilling Mixed Coal Mining

    Directory of Open Access Journals (Sweden)

    Yanli Huang

    2017-07-01

    Full Text Available Based on techniques of close upper protective coal-rock layer mining, relieved gas extraction, and underground gangue washing-discharging-backfilling, this paper initiates the concept of mixed fully-mechanized coal mining, which combines a solid backfilling method and a caving method (hereinafter referred to as “backfill and caving mixed mining”. After the principle and key techniques are introduced, a physical simulation experiment and a numerical simulation are used to study the characteristics of the overlying strata’s fracture development, the main roof subsidence, the stress field and its influence area in the transition area with the length ratios of the backfilling section and the caving section, and the advancing distance of the mixed longwall face. Thus, the lengths of the caving section and the backfilling section, the parameters of the support system in the transition section, and the design process of the mixed longwall face are presented. In practice, the mixed longwall face Ji15-31010 in Ping-dingshan No. 12 Colliery proves that the designed lengths of 120 m and 100 m for the backfilling section and the caving section, respectively, are appropriate. The monitoring results of the hydraulic support working resistance show that the supports were working well in general; the maximum growth height of the overlying strata fracture is 18 m; the gas drainage efficiency is up to 80% and the average gas concentration is 0.1 g/m3; a large quantity of gangue generated in the Ji14 seam is disposed underground; coal and gas are extracted simultaneously; and significant environmental and economic benefits are realized.

  14. Application of multimedia in strategic management in engineering design associated with occupational hazards of dust

    Energy Technology Data Exchange (ETDEWEB)

    Atkins, A.S.; Aziz, N.I.; Rao, B.S. [Staffordshire University, Stafford (United Kingdom). School of Computing

    1996-12-31

    The paper deals with the application of Multimedia to synthesis the aerodynamic patterns of airborne dust flow along the longwall face in a coal mine. The use of multimedia enables modelling techniques to be illustrated using graphical and photographic information. The multimedia techniques permit design systems, linked to CAD/CAM, to be used to design control techniques and air velocity on respirable dust flow behaviour. Results from several field sites are used to demonstrate the effectiveness of multimedia linked to Executive Information System (EIS) to provide strategic system decision support. 9 refs., 4 figs.

  15. Subsidence monitoring program at Cyprus Coal's Colorado operations

    International Nuclear Information System (INIS)

    Stewart, C.L.; Shoemaker, J.E.

    1992-01-01

    Published subsidence data for the western United States is limited in comparison with data for the east. This paper summarizes the results of a subsidence monitoring program above two longwall panels at the Foidel Creek Mine located in northwest Colorado. The monitoring area is characterized by overburden ranging from 1000 ft to 1100 ft in thickness. the surface slope parallels the dip of the bedding at approximately 5 deg. Average mining height is 9 ft. Smax averaged 3.4 ft. Draw angles averaged 15 deg for up-dip ribsides and 19 deg for down-dip ribsides. A site-specific profile function is developed from the data

  16. No impediments to introducing LTCC to Australia: researchers

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-03-15

    China has achieved significant production improvements in coal mining as a result of development and application of the Longwall Top Coal Caving (LTCC) method. The University of New South Wales has reviewed potential sites in Australia where LTCC could find application and is currently conducting research aimed at better geotechnical site characterization. Major benefits of the method include: operating cost reductions; resource recovery, mine financial performance and mine safety. The geological factors considered to be most important for implementation of LTCC in Australia are: coal seam capability/fragmentation; the effect of massive strata units in immediate/near seam roof; and the effect of high horizontal stress ratios. 1 ref., 1 fig.

  17. Mechanism of rigid overlaying of carboniferous strata failure in face mining in the case of multiseams deposit

    Czech Academy of Sciences Publication Activity Database

    Jiránková, E.; Staš, Lubomír; Kajzar, Vlastimil; Doležalová, Hana

    2013-01-01

    Roč. 10, č. 2 (2013), s. 189-195 ISSN 1214-9705 R&D Projects: GA MŠk ED2.1.00/03.0082; GA MV VG20102014034 Institutional support: RVO:68145535 Keywords : subsidence trough * rock mass * overlaying strata * longwall mining * tensor stress measurement Subject RIV: DH - Mining, incl. Coal Mining Impact factor: 0.667, year: 2013 http://www.irsm.cas.cz/materialy/acta_content/2013_02/acta_170_08_Jirankova_189-195.pdf

  18. Shortwall mining with powered supports at Venkatesh Khani No. 7 incline - collating the experiences

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, M.S.; Sastry, B.D. [Singareni Collieries Co. Ltd. (India)

    1998-02-01

    The Venkatesh Khani No. 7 mine has been worked by longwall techniques. An experiment was made with using shortwall mining to evaluate the feasibility of partial extraction with mechanisation by reducing the width of the face. Several blocks were selected and attention was paid to subsidence during shortwall working. Details are given of strata control, scientific investigations, instrumentation, measurement cycles, roof to floor convergence at the face, gateroad convergence, extensometry, experience with falls, and subsidence during this project. It is concluded that shortwall mining can be safely used below surface structures and for pillar extraction with zero ground movement. 2 refs., 10 figs., 4 tabs.

  19. High pressure water jet mining machine

    Science.gov (United States)

    Barker, Clark R.

    1981-05-05

    A high pressure water jet mining machine for the longwall mining of coal is described. The machine is generally in the shape of a plowshare and is advanced in the direction in which the coal is cut. The machine has mounted thereon a plurality of nozzle modules each containing a high pressure water jet nozzle disposed to oscillate in a particular plane. The nozzle modules are oriented to cut in vertical and horizontal planes on the leading edge of the machine and the coal so cut is cleaved off by the wedge-shaped body.

  20. Use of ground penetrating radar in underground coal mining

    Science.gov (United States)

    Ralston, Johnathon C.; Hainsworth, David W.

    2000-04-01

    This paper reports on a novel application of ground penetrating radar to a longwall steering problem in the coal mining industry. The main goal of the work was to determine whether a radar-based system could be used to detect coal-rock interfaces in order to establish a suitable mining horizon within the coal seam. We investigated the feasibility of the radar unit and determined that a positive correlation exists between the radar data and known coal-rock interface geology. We also highlight some of the unique challenges encountered when attempting to develop electrical equipment that is suitable for hazardous underground coal mining environments.

  1. Generalised empirical method for predicting surface subsidence

    International Nuclear Information System (INIS)

    Zhang, M.; Bhattacharyya, A.K.

    1994-01-01

    Based on a simplified strata parameter, i.e. the ratio of total thickness of the strong rock beds in an overburden to the overall thickness of the overburden, a Generalised Empirical Method (GEM) is described for predicting the maximum subsidence and the shape of a complete transverse subsidence profile due to a single completely extracted longwall panel. In the method, a nomogram for predicting the maximum surface subsidence is first developed from the data collected from subsidence measurements worldwide. Then, a method is developed for predicting the shapes of complete transfer subsidence profiles for a horizontal seam and ground surface and is verified by case studies. 13 refs., 9 figs., 2 tabs

  2. Coal output dependence on parameters of tectonic disturbances

    Energy Technology Data Exchange (ETDEWEB)

    Kozel, K.K. (L' vovsko-Volynskaya GREh (USSR))

    1990-10-01

    Analyzes effects of tectonic dislocations of coal seams on output of longwall faces in 5 mines of the Chervonograd area with 4 coal seams. The seams are mined by KM97 face systems with the 1K101 shearer loader and the KM87 system with the GSh68 shearer loader. Fault length and throw in relation to coal panel dimensions and coal seam thickness are analyzed. Effects of tectonic dislocations on face advance rates and coal output per face are calculated. Correlations of tectonic dislocation parameters (fault throw and range) and coal output per face are determined. 4 refs.

  3. Finite element modeling of surface subsidence induced by underground coal mining

    International Nuclear Information System (INIS)

    Su, D.W.H.

    1992-01-01

    The ability to predict the effects of longwall mining on topography and surface structures is important for any coal company in making permit applications and anticipating potential mining problems. The sophisticated finite element model described and evaluated in this paper is based upon five years of underground and surface observations and evolutionary development of modeling techniques and attributes. The model provides a very powerful tool to address subsidence and other ground control questions. The model can be used to calculate postmining stress and strain conditions at any horizon between the mine and the ground surface. This holds the promise of assisting in the prediction of mining-related hydrological effects

  4. An Innovative Support Structure for Gob-Side Entry Retention in Steep Coal Seam Mining

    OpenAIRE

    Jianguo Ning; Jun Wang; Tengteng Bu; Shanchao Hu; Xuesheng Liu

    2017-01-01

    This study considered longwall working face No. 41101—located in a steeply inclined coal seam at the Awuzisu coal mine in Xinjiang, China—as an example in which macroscopic shear cracks had occurred in the cement-based filling body of the gob-side entry retention structure. A mechanical model of the support structure for the gob-side entry retention was first established. Then, field observations and laboratory tests were used to obtain the force exerted by the coal wall on the main roof, the...

  5. Profiles of noise exposure levels in South African mining

    CSIR Research Space (South Africa)

    Edwards, A

    2011-05-01

    Full Text Available in occupations in longwall sections of U.S.A. coal mines are exposed to levels in excess of exposure levels regarded as safe for the prevention of NIHL. Examples of the reported coal miners? exposure levels are that stageloaders are exposed to noise levels.... The results of other aspects of the study are reported elsewhere.15,16 METHODOLOGY The multi-task research design implemented by the Concawe Health Management Group (CHMG) that assessed gasoline vapour exposures of European petroleum industry employees...

  6. Geomechanical effects of stress shadow created by large-scale destress blasting

    Directory of Open Access Journals (Sweden)

    Isaac Vennes

    2017-12-01

    Full Text Available This study aims to determine if large-scale choked panel destress blasting can provide sufficient beneficial stress reduction in highly-stressed remnant ore pillar that is planned for production. The orebody is divided into 20 stopes over 2 levels, and 2 panels are choke-blasted in the hanging wall to shield the ore pillar by creating a stress shadow around it. A linear-elastic model of the mining system is constructed with finite difference code FLAC3D. The effect of destress blasting in the panels is simulated by applying a fragmentation factor (α to the rock mass stiffness and a stress reduction factor (β to the current state of stress in the region occupied by the destress panels. As an extreme case, the destress panel is also modeled as a void to obtain the maximum possible beneficial effects of destressing and stress shadow. Four stopes are mined in the stress shadow of the panels in 6 lifts and then backfilled. The effect of destress blasting on the remnant ore pillar is quantified based on stress change and brittle shear ratio (BSR in the stress shadow zone compared to the base case without destress blasting. To establish realistic rock fragmentation and stress reduction factors, model results are compared to measured stress changes reported for case studies at Fraser and Brunswick mines. A 1.5 MPa immediate stress decrease was observed 20 m away from the panel at Fraser Mine, and a 4 MPa immediate stress decrease was observed 25 m away at Brunswick Mine. Comparable results are obtained from the current model with a rock fragmentation factor α of 0.2 and a stress reduction factor β of 0.8. It is shown that a destress blasting with these parameters reduces the major principal stress in the nearest stopes by 10–25 MPa. This yields an immediate reduction of BSR, which is deemed sufficient to reduce volume of ore at risk in the pillar.

  7. A new method to calculate permeability of gob for air leakage calculations and for improvements in methane control

    Energy Technology Data Exchange (ETDEWEB)

    Karacan, C.O. [National Inst. for Occupational Safety and Health, Pittsburgh, PA (United States). Office of Mine Safety and Health Research

    2010-07-01

    Although longwall underground mining can maximize coal production, it causes large scale disturbances of the surrounding rock mass due to fracturing and caving of the mine roof as the mine face advances. The porosity and permeability of the longwall gob can affect the methane and air flow patterns considerably. Since methane is a major hazard in underground coal mining operations, extensive methane control techniques are used to supplement the existing mine ventilation system, such as gob gas ventholes (GGV). However, the gob is rarely accessible for performing direct measurements of porosity and permeability. Therefore, this study presented a fractal approach for calculating the porosity and permeability from the size distribution of broken rock material in the gob, which can be determined from image analyses. The fractal approach constructs flow equations and fractal crushing equations for granular materials to predict porosity for a completely fragmented porous medium. The virtual fragmented fractal porous medium is exposed to various uniaxial stresses to simulate gob compaction and porosity and permeability changes during this process. It was concluded that the use of this fractal approach will result in better predictions regarding the flow amount and flow patterns in the gob, and facilitate leakage calculations and methane control projections. 29 refs., 4 tabs., 5 figs.

  8. A section of a pacing mine timbering

    Energy Technology Data Exchange (ETDEWEB)

    Hodous, J.; Kubac, J.; Novak, Z.; Skrobalek, J.; Zajic, K.

    1982-04-15

    A section is proposed for a pacing mine support of the wall and supporting type, designed for reinforcing the operational space of a longwall. The support section differs from the known in that it has relatively large mobility with the use of single stage telescopic hydraulic uprights. The section has left and right skiis, to which the tunneling machine with an upper part is attached using a hinged link. One hydraulic upright is installed on each ski, while a device for advancing the support is installed between the skiis. It is linked using a trough with the longwall conveyor which is not shown in the figure. A complex shaped track is made on each ski with three support recesses located at a different height relative to the base of the ski. The hydraulic upright is linked by its fixed part with the upper part of with the heading machine. The support has controllable projections on two sides, each of which is inserted in a track. Moreover, the support is attached to a hydraulic power cylinder, which is hinged with one of the skiis.

  9. Industrial development of a simulation method for ore recovery evaluation

    International Nuclear Information System (INIS)

    Deraisme; De Fouquet; Fraisse

    1983-01-01

    The purpose of downstream geostatistics is to provide to engineers, responsible for mining project studies, with a method for predicting the ore reserve recovery coming from different mining methods and for choosing the best one according to economic criteria. In the case of the BEN LOMOND uranium deposit, the metal recovery at the production stage depends on the geometry of mineralized lenses. For the first step of this study the usual technique for constructing a numerical model of deposit has been used. But this does not reproduce the geological structures very precisely. The recovered reserves have been computed for three more or less selective mining methods. This has been done inputing the outlines of stopes on a digitalizer. In the case of a cut and fill method an automatic algorithm for the optimization under constraints has been developed [fr

  10. An improved mathematical model for prediction of air quantity to minimise radiation levels in underground uranium mines.

    Science.gov (United States)

    Panigrahi, Durga Charan; Sahu, Patitapaban; Mishra, Devi Prasad

    2015-02-01

    Ventilation is the primary means of controlling radon and its daughter concentrations in an underground uranium mine environment. Therefore, prediction of air quantity is the vital component for planning and designing of ventilation systems to minimise the radiation exposure of miners in underground uranium mines. This paper comprehensively describes the derivation and verification of an improved mathematical model for prediction of air quantity, based on the growth of radon daughters in terms of potential alpha energy concentration (PAEC), to reduce the radiation levels in uranium mines. The model also explains the prediction of air quantity depending upon the quality of intake air to the stopes. This model can be used to evaluate the contribution of different sources to radon concentration in mine atmosphere based on the measurements of radon emanation and exhalation. Moreover, a mathematical relationship has been established for quick prediction of air quantity to achieve the desired radon daughter concentration in the mines. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Pessimistic Determination of Mechanical Conditions and Micro/macroeconomic Evaluation of Mine Pillar Replacement

    Science.gov (United States)

    Chen, Qingfa; Zhao, Fuyu

    2017-12-01

    Numerous pillars are left after mining of underground mineral resources using the open stope method or after the first step of the partial filling method. The mineral recovery rate can, however, be improved by replacement recovery of pillars. In the present study, the relationships among the pillar type, minimum pillar width, and micro/macroeconomic factors were investigated from two perspectives, namely mechanical stability and micro/macroeconomic benefit. Based on the mechanical stability formulas for ore and artificial pillars, the minimum width for a specific pillar type was determined using a pessimistic criterion. The microeconomic benefit c of setting an ore pillar, the microeconomic benefit w of artificial pillar replacement, and the economic net present value (ENPV) of the replacement process were calculated. The values of c and w were compared with respect to ENPV, based on which the appropriate pillar type and economical benefit were determined.

  12. [Modalities in the treatment of obstructive breathing in sleep].

    Science.gov (United States)

    Vukčević, Miodrag

    2011-01-01

    The goals of OSAS therapy are to improve daytime symptoms especially excessive sleepiness, prevent neurocognitve, metabolic and cardiovascular consequences and quality of life in patients with sleep apnea. A variety of therapy exist starting from general measures that include weight reduction, change in life style, postional therapy, oral devices, upper airway surgery and pharmacotherapy. However, CPAP has been demonstrated to be the most important and highly effective therapy in these disorders. CPAP therapy dramatically improves symptoms and decreases cadriovascular and metabolic consequences stoping the occurence of the apneas. Hoewer, not all patients tolerate CPAP especially patients with milder forms of the disease. The individualised approach wich pay attention to different phenotypes and genotype could select patients for selecitively acting treatment modalities such us mandibular advancement devices and electical stimulation of the upper airway muscles.

  13. Opening of the medieval Jeroným Mine in the Czech Republic to the public

    Directory of Open Access Journals (Sweden)

    Koøínek Robert

    2003-09-01

    Full Text Available The beginnings of underground mining in the locality go back to the first half of the 16th century. The mining and sporadic exploitation then continued with many interruptions till the beginning of the 20th century. According to historic data, the depth range of mine workings is approximately 50 m. The opening of the Èistá – Jeroným complex to the public is designed to be economical with the aim to utilise, e.g. for the purpose of mining tourism, especially a medieval large-volume room that together with flooded stoped-out workings forms an inimitable atmosphere underground. This article is focused primarily on geomechanical problems connected with the opening of this complex to the public.

  14. SLOŽENO KLIZANJE U DOLINI RJEČINE

    OpenAIRE

    Benac, Čedomir; Arbanas, Željko; Jardas, Branka; Kasapović, Saša; Jurak, Vladimir

    1999-01-01

    U radu su prikazani rezultati istraživanja prve faze složenog klizišta na sjeveroistočnoj padini doline Rječine između brane Valići i naselja Pašac. Bokovi doline oblikovani su u paleogenskom flišu i kvartarnim padinskim tvorevinama. Na vrhovima su zastupljene vapnenačke stijene tvoreći litice. Nastanak istražene kompleksne pojave klizišta predodređen je geološkom gradom i morfogenezom doline Rječine. To je složeno retrogresivno klizište, koje se počelo razvijati od stope prema vrhu kosine. N...

  15. Development and prospect of china uranium mining and metallurgy

    International Nuclear Information System (INIS)

    Que Weimin; Wang Haifeng; Niu Yuqing; Gu Wancheng; Zhang Feifeng

    2007-01-01

    The development of industry of uranium mining and metallurgy in China has been reviewed generally, emphasizing on investigation approaches and application levels of uranium mining technologies such as in-situ leaching, heap leaching, stope leaching: on the basis of analysis on status of uranium mining and metallurgy and problems existed, also considering the specific features of deposit resources, the development orientation of uranium mining and metallurgy in China is pointed out. The industry of China uranium mining and metallurgy is faced to new opportunity of development and challenge in 21st century, the only way to realize sustainable development of uranium mining and metallurgy and harmonious development between economy and environment is to develop new technology on mining, ore beneficiation and metallurgy, increase the utilization level of uranium resources, low down impact on environment caused by mining and metallurgy. (authors)

  16. IMPROVMENT OF THE MINING METHOD IN THE BAUXITE MINE ĆUKOVAC-GRIŽINICA

    Directory of Open Access Journals (Sweden)

    Borislav Perić

    1992-12-01

    Full Text Available Exploitation of bauxite in region of Dalmatia has tradition of more than 50 years. The biggest underground mine of this bauxite hearing area was developed in deposit Ćukovac-Grižinica with proved workable reserves of 1.2 x 106 t. Yearly output in 1990. was 100.000 t. Production in this mine started 1987, and sublevel caving method was used. Coefficient of extraction in the parts with weak rocks is low, and unsufficient security in the conditions with firm roof. Therefore investigation of improvement of mining method was carrying on to coinside characteristics of rocks, and mining methods. Following methods were selected: sublevel caving (actually retreat stoping, sublevel sloping and sublevel caving with bauxite protection layer (the paper is published in Croatian.

  17. The mining methods at the Fraisse mine

    International Nuclear Information System (INIS)

    Heurley, P.; Vervialle, J.P.

    1985-01-01

    The Fraisse mine is one of the four underground mines of the La Crouzille mining divisions of Cogema. Faced with the necessity to mechanize its workings, this mine also had to satisfy a certain number of stringent demands. This has led to concept of four different mining methods for the four workings at present in active operation at this pit, which nevertheless preserve the basic ideas of the methods of top slicing under concrete slabs (TSS) or horizontal cut-and-fill stopes (CFS). An electric scooptram is utilized. With this type of vehicle the stringent demands for the introduction of means for fire fighting and prevention are reduced to a minimum. Finally, the dimensions of the vehicles and the operation of these methods result in a net-to-gross tonnages of close to 1, i.e. a maximum output, combined with a minimum of contamination [fr

  18. Historical perspective of early twentieth century carboniferous palaeobotany in North America

    Energy Technology Data Exchange (ETDEWEB)

    Lyons, P.C.; Morey, E.D.; Wagner, R.H. [eds.] [US Geological Survey, Reston, VA (United States)

    1995-12-31

    This book covers Carboniferous palaeobotany and palaeobotanists in North America during the early part of this century, with some reference to European palaeobotanists. The volume is published in memory of the palaeobotanists William C. Darrah, of whom there is a biography here. Portraits of selected European palaeobotanist are given: Wilhelmus Josephus Jongmans, Walter Gothan, Paul Bertrand, Carl Rudolf Florin and Marie Stopes. Portraits of selected North American palaeobotanists are also provided: David White, Reinhardt Thiessen, Elias Howard Sellards, Maxim Konrad Elias, Adolf Carl Noe, Fredda Doris Reed, Walther Andrew Bell, James Morton Schopf, Chester A. Arnold, Charles Brian Read, Leonard Richard Wilson, and Henry Nathaniel Andrews Jr. The biographies of three prominent amateur collectors are also presented: Frederick Oliver Thompson, George Langford Sr., and John Edward Jones. The book finishes with articles on Pennsylvanian zonation, the Stephanian, coal balls, sedimentology and taphonomy, and carboniferous palynology. 10 of the papers have been abstracted separately on the IEA Coal Research CD-ROM.

  19. Etude de la consolidation gravitaire en colonnes des remblais miniers cimentes en pate

    Science.gov (United States)

    El Aatar, Omar

    2011-12-01

    The challenge of underground mines backfilling in Abitibi region remains a major topic of investigation by many researchers in recent decades. For example, it has been observed in the backfilled stopes that the top of the fill settles systematically few days after its placement (by an average value varying between 0.9 and 1.5 m observed at Louvicourt mine). In addition, the strength of the cemented paste backfill (CPB) increases substantially, almost three times between the top and bottom of the backfilled stope. Some studies have also shown that the strength (unconfined compressive strength or UCS) of in situ CPB core specimens was 2 to 4 times of that of specimens of the equivalent lab-prepared CPB poured into plastic moulds. Among the many possible causes which could explain these observations, one can mention the self-weight consolidation of CPB. The main objective of this research is to understand the physical phenomena that govern the mechanical strength development within paste backfill after placement. To this end, three PVC columns, each of 3 m high, were manufactured and installed at the Louvicourt (LVT) mine and LaRonde (LRD) mine backfill plants to be in-filled. The column tests performed at the Louvicourt mine backfill plant allowed simulating different drainage configurations of a backfilled stope, namely, full drainage, partial drainage and no drainage while column tests performed at the LaRonde mine allowed comparing the response of three different paste backfill mix recipes for unique drainage condition: combined lateral and vertical drainage. Before the columns in-filling, the effect of mixing time on the slump height value of CPB was evaluated. Each column was then in-filled with CPB having a slump height similar to that of the fill used underground and in two sequences of in-filling of about 1.45 to 1.5 m over a time period of 24 hours. The monitoring of in-filled columns with CPB lasted for 5 days and consisted of measuring the amount of

  20. Application of Computer Aided Design (CADD) in data display and integration of numerical and field results - Stripa phase 3

    International Nuclear Information System (INIS)

    Press, D.E.; Halliday, S.M.; Gale, J.E.

    1990-12-01

    Existing CAD/CADD systems have been reviewed and the micro-computer compatible solids modelling CADD software SilverScreen was selected for use in constructing a CADD model of the Stripa site. Maps of the Stripa mine drifts, shafts, raises and stopes were digitized and used to create three-dimensional images of the north-eastern part of the mine and the SCV site. In addition, the use of CADD sub-programs to display variation in fracture geometry and hydraulic heads have been demonstrated. The database developed in this study is available as either raw digitized files, processed data files, SilverScreen script files or in DXF or IGES formats; all of which are described in this report. (au)

  1. Deformation Failure Characteristics of Coal Body and Mining Induced Stress Evolution Law

    Directory of Open Access Journals (Sweden)

    Zhijie Wen

    2014-01-01

    Full Text Available The results of the interaction between coal failure and mining pressure field evolution during mining are presented. Not only the mechanical model of stope and its relative structure division, but also the failure and behavior characteristic of coal body under different mining stages are built and demonstrated. Namely, the breaking arch and stress arch which influence the mining area are quantified calculated. A systematic method of stress field distribution is worked out. All this indicates that the pore distribution of coal body with different compressed volume has fractal character; it appears to be the linear relationship between propagation range of internal stress field and compressed volume of coal body and nonlinear relationship between the range of outburst coal mass and the number of pores which is influenced by mining pressure. The results provide theory reference for the research on the range of mining-induced stress and broken coal wall.

  2. The current state of abortion law and practice in Northern Ireland.

    Science.gov (United States)

    Daniels, Pauline; Campbell, Patricia; Clinton, Alison

    This paper reviews current abortion law and practice in Northern Ireland (NI). It explores the origins of NI's abortion law and its complexity in relation to current practice. It reviews issues relating to women seeking terminations in NI and Great Britain and reviews attempts by the Family Planning Association in NI to require the Department of Health, Social Services and Public Safety NI to clarify the current legal basis for termination of pregnancy and to provide guidance for health professionals engaged in this practice. The paper also discusses some of the issues surrounding abortion in NI and seeks to explain why this subject is causing controversy and debate, especially following a judicial review in February and Marie Stopes opening a termination service in Belfast.

  3. IUD discontinuation rates, switching behavior, and user satisfaction: findings from a retrospective analysis of a mobile outreach service program in Pakistan.

    Science.gov (United States)

    Azmat, Syed Khurram; Hameed, Waqas; Mustafa, Ghulam; Hussain, Wajahat; Ahmed, Aftab; Bilgrami, Mohsina

    2013-01-01

    In Pakistan, the uptake rate for the intrauterine device (IUD) is very low at 2.5%. The most popular modern contraceptive methods in Pakistan are female sterilization and use of condoms. The Marie Stopes Society established its mobile outreach service delivery program with the aim of increasing use of modern quality contraceptive services, including the long-term reversible IUD, by women living in hard-to-reach areas. The present study attempts to assess IUD discontinuation rates and associated factors, including switching behavior and level of satisfaction with this type of service delivery. Using a cross-sectional approach, we contacted 681 women who had received an IUD from the Marie Stopes Society mobile outreach program during July and August 2009. Successful interviews were conducted with 639 of these women using a structured questionnaire. The data were analyzed with Stata 11.2 using simple descriptive Chi-square and Cox proportional techniques. Analysis revealed that 19.4% (95% confidence interval 16.3-22.5) of the women discontinued use of their IUD at 10 months and, of these women, the majority (69.4%) cited side effects as the main reason for discontinuation. Other factors, such as geographical catchment province, age of the woman, history of contraceptive use before IUD insertion, and side effects following insertion of the device, were found to be significantly associated with IUD. Amongst the women who had their IUD removed, 56.5% did not switch to any other contraceptive method, while 36.3% switched to either short-term or traditional methods, such as withdrawal, rhythm, and folk methods. Degree of satisfaction with the device was also significantly associated with discontinuation. Early discontinuation and not switching to another contraceptive method increases the risk of unplanned pregnancy. Health care workers should be trained in managing clients' concerns about the IUD to prevent discontinuation and providing counseling services for clients to

  4. Medical abortion practices among private providers in Vietnam

    Directory of Open Access Journals (Sweden)

    Park MH

    2013-09-01

    Full Text Available Min Hae Park,1 Thang Huu Nguyen,2 Anh Thi Ngoc Dang,2 Thoai Dinh Ngo1 1Research, Monitoring and Evaluation Team, Health System Department, Marie Stopes International, London, UK; 2Research and Metrics Team, Marie Stopes International Vietnam, Ha Noi, Vietnam Objective: To describe medical abortion (MA practices among private providers in Vietnam. Methods: The study subjects were women (n = 258 undergoing early MA through 12 private providers in Hanoi during February-June 2012. The women were interviewed on the day of their procedure and were followed up by telephone 14 days after mifepristone administration. Results: Of the 258 women in the study, 97% used a regimen of mifepristone plus misoprostol; 80% were instructed to administer misoprostol at home. MA resulted in a complete termination in 90.8% of cases. All women were provided with information on potential complications and were instructed to return for a follow-up visit. We successfully followed up 77.5% (n = 200 of participants by telephone, while nearly two-thirds of women returned to the clinic for a follow-up visit. At follow up, 39.5% of women reported having used a Help line service, while 7% had sought help from a health provider. A high unmet need for postabortion family planning was identified. Conclusion: Follow up of women, postabortion care, and the provision of family planning have been identified as important areas to address for strengthening MA services in the private sector in Vietnam. Keywords: misoprostol, mifepristone, abortion, mhealth, Vietnam

  5. Pushing up smoking incidence: plans for a privatised tobacco industry in Moldova.

    Science.gov (United States)

    Gilmore, Anna B; Radu-Loghin, Cornel; Zatushevski, Irina; McKee, Martin

    Moldova, one of the former Soviet republics and Europe's poorest country, has so far resisted pressure to privatise its tobacco industry. This paper examines the policies pursued by the transnational tobacco companies in Moldova in order to inform the ongoing debate about tobacco industry privatisation. We analysed relevant internal industry documents made public through litigation. The documents suggest that although a competitive tender for the state owned monopoly was later announced, British American Tobacco (BAT) and the German manufacturer Reemtsma each initially sought to secure a closed deal, with BAT accusing Reemtsma of underhand tactics. Imperial Tobacco, which now owns Reemstma, was unable to comment on these allegations as it only acquired Reemstma after the events in question. BAT sought to acquire a monopoly position, bolstered by excise rules developed by the company that would uniquely favour its products. Despite hoping to establish a monopoly, it planned intensive marketing, as if in a competitive market, aiming to target young urban dwellers, particularly opinion leaders. In so doing it predicted that smoking uptake would increase, especially among women. The documents also suggest that BAT was aware of the sensitive nature of its plans to cull the processing workforce and aimed to present "sanitised" information on future employment levels to the Moldovans. The potential for tobacco industry privatisation to undermine tobacco control and promote cigarette consumption is highlighted and is consistent with economic theory. Countries planning tobacco industry privatisation should ensure a transparent and competitive privatisation process, seek to prevent the predicted increase in consumption by implementing effective tobacco control policies and consider the impacts on employment. Multilateral financial organisations promoting tobacco industry privatisation could ensure their loan conditions protect public health by making the implementation of

  6. Three year follow-up of an early childhood intervention: is movement skill sustained?

    Directory of Open Access Journals (Sweden)

    Zask Avigdor

    2012-10-01

    Full Text Available Abstract Background Movement skill competence (e.g. the ability to throw, run and kick is a potentially important physical activity determinant. However, little is known about the long-term impact of interventions to improve movement skills in early childhood. This study aimed to determine whether intervention preschool children were still more skill proficient than controls three years after a 10 month movement skill focused intervention: ‘Tooty Fruity Vegie in Preschools’. Methods Children from 18 intervention and 13 control preschools in NSW, Australia were assessed at ages four (Time1, five (T2 and eight years (T3 for locomotor (run, gallop, hop, leap, horizontal jump, slide and object control proficiency (strike, bounce, catch, kick, overhand throw, underhand roll using the Test of Gross Motor Development-2. Multi-level object control and locomotor regression models were fitted with variables time, intervention (yes/no and a time*intervention interaction. Both models added sex of child and retained if significant, in which case interactions of sex of child with other variables were modelled and retained. SPSS (Version 17.0 was used. Results Overall follow-up rate was 29% (163/560. Of the 137 students used in the regression models, 53% were female (n = 73. Intervention girls maintained their object control skill advantage in comparison to controls at T3 (p = .002, but intervention boys did not (p = .591. At T3, there were no longer intervention/control differences in locomotor skill (p = .801. Conclusion Early childhood settings should implement movement skill interventions and more intensively target girls and object control skills.

  7. Examination of motor skill competency in students: evidence-based physical education curriculum

    Directory of Open Access Journals (Sweden)

    Weiyun Chen

    2017-02-01

    Full Text Available Abstract Background Researchers found that children with a competent level of motor skill performance are more likely to be physically active. This study examined how well K-1 students demonstrated motor skill competency in relation to Physical Education Content Standard 1. Methods Participants were K-1 grade students (N = 1,223-1,588; boys = 568–857; girls = 526–695; Mean age = 5.5 yrs old who were enrolled in nine elementary schools. The K-1 students’ motor skill competency in running, weight transferring, hand dribbling, and underhand catching skills was assessed using four PE Metrics skill assessment rubrics in the intervention year 1 and year 2, respectively. Data were analyzed by means of descriptive statistics and independent sample t-tests. Results The students in the intervention year 1 and year 2 cohorts performed at the Competent Level or higher in the four skill assessments. The prevalence of the students’ demonstration of skill competency across the four skills was high in the two intervention years. The intervention year 2 cohort scored significantly higher than the intervention year 1 cohort in the four skill assessments. The boys significantly outperformed than the girls in the two manipulative skills in the intervention year 1 and in the two manipulative skills and the weight transferring skill in the intervention year 2. No gender differences in the running skill in either year were found. Conclusions The evidence-based CATCH PE play a critical role in developing and building K-1 students’ ability to demonstrate motor skill competency in four fundamental skills. Trial registration ClinicalTrials.gov ID: NCT03015337 , registered date: 1/09/2017, as "retrospectively registered".

  8. Cost comparison of selected US and Polish coal mines, August 1993

    International Nuclear Information System (INIS)

    1993-08-01

    This report on the Polish coal industry is the fifth in a series of studies on coal exporting countries requested by the House Appropriations Committee. The committee requested that the basic differences in mining costs for U.S. and foreign mines be identified, especially those costs incurred in complying with health, safety, and environmental regulations. Basic costs in extracting raw coal are analyzed in this report for underground longwall mining operations, the only mining method employed in Poland for hard coal. In this report there is also a limited analysis of the relative market competitiveness of selected Polish and U.S. steam and metallurgical coal mines in the European electric utility and metallurgical coal markets

  9. The stability of structure's foundation rockmass over shallow abandoned mine goafs and its treatment - a case study

    International Nuclear Information System (INIS)

    Guo, G.; He, G.; Qiao, Z.; Yang, S.; Deng, K.; Gao, J.

    1996-01-01

    A heavy coal dressing plant is constructed on an area seriously damaged by underground longwall mining in one of China's collieries. The Southwest of the main dressing plant stands on the ground over shallow abandoned mine goafs. Using the methods of boring and geophysical exploration and mining subsidence analysis, this paper studies the 3D distribution of fracture zones caused by mining's influence. Combined with the result of FEM, the paper analyses the stability of the main building's foundation rock mass, advances and adopts some safety measures, such as grouting the mining the fractured rockmass to consolidate it, appropriately designing the building to improve its anti-deformation ability, etc. The inspection results of geophysical prospecting show that consolidation grouting has attained the expected results. The settlement observation indicates that the settlement of the main building is smooth. 4 refs., 4 figs

  10. Analysis characteristics determination of electrohydraulic control system operation to reduce the operation time of a powered roof support

    Science.gov (United States)

    Szurgacz, Dawid

    2018-01-01

    The article discusses basic functions of a powered roof support in a longwall unit. The support function is to provide safety by protecting mine workings against uncontrolled falling of rocks. The subject of the research includes the measures to shorten the time of roof support shifting. The roof support is adapted to transfer, in hazard conditions of rock mass tremors, dynamic loads caused by mining exploitation. The article presents preliminary research results on the time reduction of the unit advance to increase the extraction process and thus reduce operating costs. Conducted stand tests showed the ability to increase the flow for 3/2-way valve cartridges. The level of fluid flowing through the cartridges is adequate to control individual actuators.

  11. Determination of intensity functions for predicting subsidence from coal mining, potash mining, and groundwater withdrawal using the influence function technique

    Energy Technology Data Exchange (ETDEWEB)

    Triplett, T.; Yurchak, D. [Twin Cities Research Center, Bureau of Mines, US Dept. of the Interior, Minneapolis, MN (United States)

    1996-12-31

    This paper presents research, conducted by the Bureau of Mines, on modifying the influence function method to predict subsidence. According to theory, this technique must incorporate an intensity function to represent the relative significance of the causes of subsidence. This paper shows that the inclusion of a reasonable intensity function increases the accuracy of the technique, then presents the required functions for case studies of longwall coal mining subsidence in Illinois, USA, potash mining subsidence in new Mexico, USA, and subsidence produced by ground water withdrawal in California, USA. Finally, the paper discusses a method to predict the resultant strain from a simply measured site constant and ground curvatures calculated by the technique. (orig.)

  12. Stress distribution characteristics in the vicinity of coal seam floor

    Science.gov (United States)

    Cui, Zimo; Chanda, Emmanuel; Zhao, Jingli; Wang, Zhihe

    2018-01-01

    Although longwall top-coal caving (LTCC) has been a popular, more productive and cost-effective method in recent years, roadway floor heave and rock bursts frequently appear when exploiting such coal seams with large dip angle. This paper proposes addressing this problem by adopting three-dimensional roadway layout of stagger arrangement (3-D RLSA). In this study, the first step was to analyse the stress distribution characteristics in the vicinity of coal seam floor based on the stress slip line field theory. In the second step, numerical calculation using FLAC3D was conducted. Finally, an evaluation of the 3-D RLSA for solving this particular issue was given. Results indicate that for this particular mine the proposed 3-D RLSA results in 24% increase in the coal recovery ratio and a modest reduction in excavation and maintenance costs compared to the conventional LTCC method.

  13. Selected legal aspects of traumatism and the education system of workers

    Energy Technology Data Exchange (ETDEWEB)

    Latman, A.M. (Shakhta No 3 Velikomostovskaya (USSR))

    1990-08-01

    Analyzes legal aspects of responsibility for accidents in underground coal mines in the USSR. The existing system of classification of types of coal miner occupations (the EKTS job description system) introduces an excessively large number of occupational groups. Each group knows only one type of operation (e.g. only operations of a driver of a shearer loader, or control of powered supports at a longwall face). When a driver of a shearer loader advances powered supports and an accident occurs he has an automatic legal responsibility as he has performed operations exceeding his job description. The same situation occurs if a supervisor instructs a coal miner to participate in an emergency rescue operation which exceeds the standard job description of a miner. Such a system is found to be irrational; introducing changes in the system of job descriptions for coal miners in the USSR is recommended.

  14. The Pittsburgh seam: the beast of the East

    Energy Technology Data Exchange (ETDEWEB)

    Morey, M. [RDI Consulting, Arlington, VA (United States)

    2001-08-01

    The Pittsburgh seam region is made up of large underground mines in a small portion of northern Appalachia. Production from these mines rose to 80 million tons in the late 1990s. Most mines employ longwall technology. Resource Data International examined coal production on a quarterly basis at each of the mines working the Pittsburgh seam. The review showed that while output ranged between 18 to 21 million tons on a quarterly basis, mining efficiency has been recording steady gains. Productivity has increased to nearly 6 tons per worker-hour in the first quarter of 2001. The fairly diverse markets for Pittsburgh seam coal are discussed in the short article. 1 fig., 1 tab.

  15. Numerical Simulation of Squeezing Failure in a Coal Mine Roadway due to Mining-Induced Stresses

    Science.gov (United States)

    Gao, Fuqiang; Stead, Doug; Kang, Hongpu

    2015-07-01

    Squeezing failure is a common failure mechanism experienced in underground coal mine roadways due mainly to mining-induced stresses, which are much higher than the strength of rock mass surrounding an entry. In this study, numerical simulation was carried out to investigate the mechanisms of roadway squeezing using a novel UDEC Trigon approach. A numerical roadway model was created based on a case study at the Zhangcun coal mine in China. Coal extraction using the longwall mining method was simulated in the model with calculation of the mining-induced stresses. The process of roadway squeezing under severe mining-induced stresses was realistically captured in the model. Deformation phenomena observed in field, including roof sag, wall convexity and failed rock bolts are realistically produced in the UDEC Trigon model.

  16. Model proposal for representing a deep coal mine spatial and functional structure

    Directory of Open Access Journals (Sweden)

    Sebastian Iwaszenko

    2017-01-01

    Full Text Available Underground coal mining usually requires the development of a set of underground corridors (workings. The workings fulfill many different functions. They are used for transportation, ventilation, dewatering and even escape pathways. The proposition of a formal representation of a working's structure for deep coal mining has been presented. The model was developed as a basis for the software system, support management and operational activities for longwall deep mine. The proposed solution is based on graph formalism along with its matrix representation. However, the idea of matrix representation is enhanced. Not only are the topological properties of workings structure considered, but also information about their functions and spatial characteristic. The object model was designed and implemented based upon the matrix idea.

  17. Economic baselines for current underground coal mining technology

    Science.gov (United States)

    Mabe, W. B.

    1979-01-01

    The cost of mining coal using a room pillar mining method with continuous miner and a longwall mining system was calculated. Costs were calculated for the years 1975 and 2000 time periods and are to be used as economic standards against which advanced mining concepts and systems will be compared. Some assumptions were changed and some internal model stored data was altered from the original calculations procedure chosen, to obtain a result that more closely represented what was considered to be a standard mine. Coal seam thicknesses were varied from one and one-half feet to eight feet to obtain the cost of mining coal over a wide range. Geologic conditions were selected that had a minimum impact on the mining productivity.

  18. Shooting on shift: Conventional mining utilizing permissible explosives underground in southeastern Illinois

    International Nuclear Information System (INIS)

    Wooton, D.G.

    1986-01-01

    Presently, 98 percent of all underground coal mined in Illinois is produced by either continuous or longwall miner. Conventional mining had declined due to various factors. Conventional producing sections require one-third more personnel than continuous miner sections. Two additional pieces of equipment are required on a conventional section. More importantly, the limitations of using compressed air as a means of breaking down cut coal in Illinois left the industry behind the other states who use permissible explosives. The use of high pressure air unnecessarily exposed miners to the hazards of ruptured air lines and excessive exposure to a half-shot coal face, unsupported roof, and dusty conditions. For conventional mining to be considered safe and feasible, shooting-on-shift with permissible explosives is necessary

  19. Recent developments in coal mining technology and their impact on miners' health.

    Science.gov (United States)

    Taylor, L D; Thakur, P C

    1993-01-01

    Advances in technology have significantly reduced the long-term health risks associated with underground coal mining. While the potential risks include exposure to hazardous substances and noise, the reduction of respirable dust in the workplace has been emphasized here because of the greater probability of exposure and the well-documented consequences. Since enactment of the Mine Health and Safety Act of 1969, great strides have been made in reducing worker exposure to respirable dust. As production rates continue to increase, particularly in longwall sections, continued advances in dust control technology will be required. These advances will be needed to meet existing, and perhaps even more stringent future, exposure limits. Mechanization has resulted in a significant reduction in exposure to hazards while increasing productivity. Use of remotely controlled equipment is also increasing rapidly, and efforts are underway to develop completely automated mining systems. These automated systems may further reduce the risk of health impairment due to the underground working environment.

  20. Electrical surveys in detection of seam displacements in mines of the L'vovsko-Volynskii basin

    Energy Technology Data Exchange (ETDEWEB)

    Matyuschechkin, V.F.; Karavaev, V.Ya.; Kozel, K.K.

    1985-04-01

    Tectonic dislocations are one of the major factors increasing mining cost in the L'vovsko-Volynskii basin. Three tectonic dislocations fall on each long pillar mined by longwall faces. Surveying methods used in the basin for forecasting faults and other tectonic dislocations are discussed. Electrical surveys used in the basin are characterized. Schemes for electric logging used in the basin are discussed: the TEhP-P sequential three-electrode electric logging, the EhDEhP-P sequential equatorial-dipole electric logging, the EhP-P sequential electric logging, the TEhP three-electrode electric logging, the EhDEhP equatorial-dipole electric logging, the EhP electric logging, and the SEhP symmetrical electric profiling. Electrode array in these methods is described. Efficiency of detecting low-amplitude tectonic dislocations using electric logging in the basin is high and amounts to about 80%.

  1. Parameters characterizing distribution of main lateral workings in destressed zones

    Energy Technology Data Exchange (ETDEWEB)

    Bakhtin, A.F.

    1984-11-01

    Mine drivage in deep coal mines in the Donbass and site selection for level or inclined workings are comparatively evaluated. Optimizing position of a mine working in relation to working faces in the same seam and in other coal seams is analyzed. The optimization is aimed at reducing deformation of workings. Four schemes of mine working distribution are: main roadways of a mining level are driven in destressed strata; mine roadways are driven in rock strata prior to stress relaxation by mining; a combined scheme (one roadway, in most cases an incline, is driven in rock strata prior to stress relaxation; two roadways are driven at a later stage after destressing of the rock strata); a so-called joint scheme in which inclined mine roadways are driven in strata destressed by an advancing longwall face. Recommendations are made for the use of the four mine drivage schemes at mining depths to 1000 m and deeper. 7 references.

  2. Improving schemes for planning mining operations in deep mines in the Donbass. Sovershenstvovanie skhem planirovki gornykh rabot na glubokikh shakhtakh Donbassa

    Energy Technology Data Exchange (ETDEWEB)

    Bakhtin, A.F.; Batmanov, Yu.K.

    1984-01-01

    This book discusses effects of increasing mining depth in the Donbass on schemes of underground mining and hazards associated with increasing strata stresses, methane emission and higher temperatures. Mining and geologic conditions in the Donbass are characterized: coal seam thickness, inclination, depth, methane emission, mechanical properties of rock strata surrounding coal seams, coal seam properties, water influx rates, temperature gradients. In the next 2 decades the average mining depth in the Donbass will increase to 850 m or 900 m while the maximum mining depth will increase to 1400 m or 1600 m. Effects of increasing depth on stresses, strata movement, roof subsidence and floor heave are analyzed. Methods for strata control efficient at large depths are comparatively evaluated: mining with caving, mining with stowing, partial stowing, mining without leaving support pillars. Three mining schemes are analyzed: longwall mining, long pillar mining and a combined scheme. Advantages of long pillar systems under conditions of great depth in the Donbass are evaluated. (20 refs.)

  3. Selection of development and working methods of coal seams in complicated mining and geological conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kaufman, L.L.; Bakhtin, A.F.; Zel' vyanskii, M.Sh. (Donetskaya Proektnaya Kontora (USSR))

    1991-07-01

    Presents the design and technological patterns developed at the Donetsk Design Office for planning mining work in difficult mining conditions. The recommended patterns of working are based on the following principles. The most progressive panel development of mine-take and horizon layout methods are used. The main workings are driven as rock drifts with support pillars or they are driven in stress relaxed zones. Seams are worked with pillars or in a combined way. The pillarless technology is based on conducting workings with coal cutting along the excavated space or on repeated utilization of workings. Reduction in stone hoisting to the surface is achieved by execution of drifts that follow the longwalls. Variants of pillar systems with panel development of mine-take and horizon layout development are shown and described.

  4. Evaluation of the reliability and effectiveness of plans for finishing off seams influenced by overlying or underlying workings without the use of pillars

    Energy Technology Data Exchange (ETDEWEB)

    Batmanov, Iu.K.; Bakhtin, A.F.; Bulavka, E.I.

    1981-01-01

    The pillar-less plan for finishing off seams using longwalls above thick pillars influenced by overlying or underlying workings earlier without the use of pillars on productive (thicker) seams is effective both from the point of view of its reliability and from the economic point of view (even when present techniques are used, as well as under complex mining-geological conditions. The system described is used on the Ukrainian Donbass mines in a total of 13% of the cases out of the overall number of contiguous, gently sloping and inclined coal seams of various thicknessess; the improvement in the amount of coal obtained can be said to have increased by a factor of 2.

  5. Ground engineering principles and practices for underground coal mining

    CERN Document Server

    Galvin, J M

    2016-01-01

    This book teaches readers ground engineering principles and related mining and risk management practices associated with underground coal mining. It establishes the basic elements of risk management and the fundamental principles of ground behaviour and then applies these to the essential building blocks of any underground coal mining system, comprising excavations, pillars, and interactions between workings. Readers will also learn about types of ground support and reinforcement systems and their operating mechanisms. These elements provide the platform whereby the principles can be applied to mining practice and risk management, directed primarily to bord and pillar mining, pillar extraction, longwall mining, sub-surface and surface subsidence, and operational hazards. The text concludes by presenting the framework of risk-based ground control management systems for achieving safe workplaces and efficient mining operations. In addition, a comprehensive reference list provides additional sources of informati...

  6. Stress analysis of three-dimensional roadway layout of stagger arrangement with field observation

    Science.gov (United States)

    Cui, Zimo; Chanda, Emmanuel; Zhao, Jingli; Wang, Zhihe

    2018-01-01

    Longwall top-coal caving (LTCC) has been a popular, more productive and cost-effective method for extracting thick (> 5 m) to ultra-thick coal seams in recent years. However, low-level recovery ratio of coal resources and top-coal loss above the supports at both ends of working face are long-term problems. Geological factors, such as large dip angle, soft rock, mining depth further complicate the problems. This paper proposes addressing this issue by adopting three-dimensional roadway layout of stagger arrangement (3-D RLSA). In this study, the first step was to analyse the stress environment surrounding head entry in the replacing working face based on the stress distribution characteristics at the triangular coal-pillar side in gob and the stress slip line field theory. In the second step, filed observation was conducted. Finally, an economic evaluation of the 3-D RLSA for extracting thick to ultra-thick seams was conducted.

  7. Degassification and methane drainage in thick and vertical coal seams worked by horizontal sublevel caving method; Drenaje y Desgasificacion de Grisu en Capas de Carbon Potentes y Verticales, Explotadas por subniveles Horizontales con sutiraje

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    The present trend of the working in spanish coal underground mines is directed towards the utilization, if the deposit characteristics permit it, of mining method by horizontal sublevels with caving. The application of this method involves an important coal volume in specific situations inside the workings cycle (shots, roof cavings, workings beginning, etc). Therefore, those considerable quantities of coal put into circulation, joined to high firedamp concentration desorbable of coal seam, produce in a instantaneous way large volumes of firedamp in the mine atmosphere with the consequent associated risk for the mine people, the stoppage of the works and its evacuation. These aforementioned risks could be avoided, or at least decreased to a great extent, through a methane capture before its circulation in openings caused by the mining works or by draining from accumulation rooms. During the last years, basically in EU countries, some researches have been accomplished about previous Degassification and methane capture in longwall faces of horizontal seams. In these researches have been studied the methane capture both from surface and from underground. In sublevel caving workings, substantially different from longwall faces workings, the techniques and capture systems utilized in the first one are not applicable to the second. The field works and measurements of this project have been mainly carried out in two mining companies located at the north of Spain, the Mina la Camocha S. A. and the S. A. Hullera Vasco Leonesa. Many methane capture tests by means of boreholes in coal seam have been carried out to determine the influence that capture boreholes exert in degassification of coal panel. Otherwise, many firedamp drainage tests in accumulation rooms have been also carried out, and a small-scale system that makes possible the capture in safe conditions have been defined and tested. (Author)

  8. Comparison of Methane Control Methods in Polish and Vietnamese Coal Mines

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    Borowski Marek

    2018-01-01

    Full Text Available Methane hazard often occurs in hard coal mines and causes very serious accidents and can be the reason of methane or methane and coal dust explosions. History of coal mining shows that methane released from the rock mass to the longwall area was responsible for numerous mining disasters. The main source of methane are coal deposits because it is autochthonous gas and is closely related with carbonification and forming of coal deposits. Degree of methane saturation in coal deposits depends on numerous factors; mainly on presence or lack of insulating layers in cover deposit that allow or do not on degasification and easily methane outflow into surroundings. Hence in coal mining there are coal deposits that contain only low degree of methane saturation in places where is lack of insulating layers till high in methane coal deposits occurring in insulating claystones or in shales. Conducting mining works in coal deposits of high methane hazard without using of special measures to combat (ventilation, methane drainage could be impossible. Control of methane hazard depends also on other co-occuring natural dangers for which used preventive actions eliminate methane hazard. Safety in mines excavating coal deposits saturated with methane depends on the correct estimation of methane hazard, drawn up forecasts, conducted observations, hazard control as well as undertaken prevention measures. Methane risk prevention includes identification and control methods of methane hazards as well as means of combating the explosive accumulation of methane in longwall workings. The main preventive actions in underground coal mines are: effective ventilation that prevents forming of methane fuses or placed methane accumulation in headings ventilated by airflow created by main fans and in headings with auxiliary ventilation, methane drainage using drain holes that are drilled from underground headings or from the surface, methanometry control of methane concentration in

  9. Comparison of Methane Control Methods in Polish and Vietnamese Coal Mines

    Science.gov (United States)

    Borowski, Marek; Kuczera, Zbigniew

    2018-03-01

    Methane hazard often occurs in hard coal mines and causes very serious accidents and can be the reason of methane or methane and coal dust explosions. History of coal mining shows that methane released from the rock mass to the longwall area was responsible for numerous mining disasters. The main source of methane are coal deposits because it is autochthonous gas and is closely related with carbonification and forming of coal deposits. Degree of methane saturation in coal deposits depends on numerous factors; mainly on presence or lack of insulating layers in cover deposit that allow or do not on degasification and easily methane outflow into surroundings. Hence in coal mining there are coal deposits that contain only low degree of methane saturation in places where is lack of insulating layers till high in methane coal deposits occurring in insulating claystones or in shales. Conducting mining works in coal deposits of high methane hazard without using of special measures to combat (ventilation, methane drainage) could be impossible. Control of methane hazard depends also on other co-occuring natural dangers for which used preventive actions eliminate methane hazard. Safety in mines excavating coal deposits saturated with methane depends on the correct estimation of methane hazard, drawn up forecasts, conducted observations, hazard control as well as undertaken prevention measures. Methane risk prevention includes identification and control methods of methane hazards as well as means of combating the explosive accumulation of methane in longwall workings. The main preventive actions in underground coal mines are: effective ventilation that prevents forming of methane fuses or placed methane accumulation in headings ventilated by airflow created by main fans and in headings with auxiliary ventilation, methane drainage using drain holes that are drilled from underground headings or from the surface, methanometry control of methane concentration in the air; location

  10. Application of Elements of TPM Strategy for Operation Analysis of Mining Machine

    Science.gov (United States)

    Brodny, Jaroslaw; Tutak, Magdalena

    2017-12-01

    Total Productive Maintenance (TPM) strategy includes group of activities and actions in order to maintenance machines in failure-free state and without breakdowns thanks to tending limitation of failures, non-planned shutdowns, lacks and non-planned service of machines. These actions are ordered to increase effectiveness of utilization of possessed devices and machines in company. Very significant element of this strategy is connection of technical actions with changes in their perception by employees. Whereas fundamental aim of introduction this strategy is improvement of economic efficiency of enterprise. Increasing competition and necessity of reduction of production costs causes that also mining enterprises are forced to introduce this strategy. In the paper examples of use of OEE model for quantitative evaluation of selected mining devices were presented. OEE model is quantitative tool of TPM strategy and can be the base for further works connected with its introduction. OEE indicator is the product of three components which include availability and performance of the studied machine and the quality of the obtained product. The paper presents the results of the effectiveness analysis of the use of a set of mining machines included in the longwall system, which is the first and most important link in the technological line of coal production. The set of analyzed machines included the longwall shearer, armored face conveyor and cruscher. From a reliability point of view, the analyzed set of machines is a system that is characterized by the serial structure. The analysis was based on data recorded by the industrial automation system used in the mines. This method of data acquisition ensured their high credibility and a full time synchronization. Conclusions from the research and analyses should be used to reduce breakdowns, failures and unplanned downtime, increase performance and improve production quality.

  11. Forecast and Prevention of Coal and Gas Outbursts in the Case of Application of a New Mining Method - Drilling of a Coal Pillar

    Directory of Open Access Journals (Sweden)

    Vlastimil Hudeček

    2010-10-01

    Full Text Available Coal and gas outbursts are one of risk factors accompanying the mining of coal in low seams in the Ostrava-Karviná Coalfield.At the use of the method of longwall mining, all coal reserves have not been mined out owing to tectonic faults. For mining outthe residual reserves, the application of a new mining method - drilling of a coal pillar was proposed.The method of mining of a coal seam utilizing long large diameter boreholes is verified in the Paskov Mine (company OKD, JSC –Czech Republic under conditions of rock mass with hazard of rock and gas outbursts in localities of residual pillars left in seams afterfinishing the mining operations performed with using the classical method of longwall working along the strike. [5]Forecast and preventive measures applied to the verification of the new method were based on previous experience withthe mining of seams with hazard of coal and gas outbursts. They accepted fully valid legislation, i.e. Ordinance of Ostrava RegionalMining Authority No. 3895/2002 and supplementary materials (Instructions and Guidelines. The proposed measures respectedthe character of the method being verified. [4]For all areas being mined, projects containing also chapters specifying the problems of ensuring the safety of mining worksand operation under conditions of hazard of coal and gas outbursts were prepared.In the contributions, basic proposals for the principles of coal and gas outburst forecast and prevention when applying the newmining method – drilling of a coal pillar are presented

  12. Observational studies in South African mines to mitigate seismic risks: implications for mine safety and tectonic earthquakes

    Science.gov (United States)

    Durrheim, Raymond; Ogaswara, Hiroshi; Nakatani, Masao; Yabe, Yasuo; Milev, Alexander; Cichowicz, Artur; Kawakata, Hironori; Moriya, Hirokazu; Naoi, Makoto; Kgarume, Thabang; Murakami, Osamu; Mngadi, Siyanda

    2014-05-01

    Seismicity poses a significant risk to workers in deep and overstressed mines, such as the gold mines in the Witwatersrand basin of South Africa, as well as inhabitants of earthquake-prone regions such as Japan. A 5-year collaborative project entitled "Observational studies in South African mines to mitigate seismic risks" was launched in 2010 to address these risks, drawing on over a century of South African and Japanese research experience with respect to mining-related and tectonic earthquakes, respectively. The project has three main aims: (1) to learn more about earthquake preparation and triggering mechanisms by deploying arrays of sensitive sensors within rock volumes where mining is likely to induce seismic activity; (2) to learn more about earthquake rupture and rockburst damage phenomena by deploying robust strong ground motion sensors close to potential fault zones and on stope hangingwalls; and (3) to upgrade the South African surface national seismic network in the mining districts. Research sites have been established at mines operated by Sibanye Gold (Hlanganani Shaft and Cooke #4 Shaft) and Anglogold Ashanti (Moab-Khotsong). More than 70 boreholes (totalling more than 2.8 km in length) have been drilled to locate "capable" faults i.e. faults that are considered likely to become seismically active as a result of mining activity and to deploy sensors. Acoustic emission sensors, strain- and tilt meters, and controlled seismic sources were installed to monitor the deformation of the rock mass, the accumulation of damage during the earthquake preparation phase, and changes in dynamic stress produced by the propagation of the rupture front. These data are being integrated with measurements of rock properties, stope closure, stope strong motion, seismic data recorded by the mine-wide network, and stress modelling. The mid-point of the 5-year project has passed. New observations of stress and the response of the rock mass to mining have already been made

  13. Youth Voucher Program in Madagascar Increases Access to Voluntary Family Planning and STI Services for Young People.

    Science.gov (United States)

    Burke, Eva; Gold, Judy; Razafinirinasoa, Lalaina; Mackay, Anna

    2017-03-24

    Young people often express a preference for seeking family planning information and services from the private sector. However, in many Marie Stopes International (MSI) social franchise networks, the proportion of young clients, and particularly those under 20 years of age, remains low. Marie Stopes Madagascar (MSM) piloted a youth voucher program that joins a supply-side intervention-youth-friendly social franchisee training and quality monitoring-with a corresponding demand-side-component, free vouchers that reduce financial barriers to family planning access for young people. Young people identified by MSM's community health educators (CHEs) received a free voucher redeemable at a BlueStar social franchisee for a package of voluntary family planning and sexually transmitted infection (STI) information and services. BlueStar social franchisees-private providers accredited by MSM-are reimbursed for the cost of providing these services. We reviewed service statistics data from the first 18 months of the youth voucher program, from July 2013 to December 2014, as well as client demographic profile data from July 2015. Findings: Between July 2013 and December 2014, 58,417 vouchers were distributed to young people by CHEs through a range of community mobilization efforts, of which 43,352 (74%) were redeemed for family planning and STI services. Most clients (78.5%) chose a long-acting reversible contraceptive (LARC), and just over half (51%) of young people benefited from STI counseling as part of their voucher service. Most (78%) services were provided in the Analamanga region (the capital and its surroundings), which was expected given the population density in this region and the high concentration of BlueStar franchisees. The client profile data snapshot from July 2015 revealed that 69% of voucher clients had never previously used a contraceptive method, and 96% of clients were aged 20 or younger, suggesting that the voucher program is successfully reaching the

  14. Comparing the World Health Organization- versus China-recommended protocol for first-trimester medical abortion: a retrospective analysis

    Directory of Open Access Journals (Sweden)

    Ngo TD

    2012-03-01

    Full Text Available Thoai D Ngo1, Min Hae Park1, Yuanhong Xiao21Research and Metrics Team, Health System Department, Marie Stopes International, London, UK; 2Research and Metrics Team, Marie Stopes International China, Beijing, ChinaObjective: To compare the effectiveness, in terms of complete abortion, of the World Health Organization (WHO- and the China-recommended protocol for first-trimester medical abortion.Methods: A retrospective analysis of clinical data from women presenting for first trimester medical abortion between January 2009 and August 2010 at reproductive health clinics in Qingdao, Xi’an, Nanjing, Nanning, and Zhengzhou was conducted. One clinic in Qingdao administered the WHO-recommended protocol (200 mg mifepristone orally followed by 0.8 mg misoprostol buccally 36–48 hours later. Four clinics in the other locations provided the China-recommended procedure (Day 1: 50 mg of mifepristone in the morning, 25 mg in the afternoon; Day 2: 50 mg of mifepristone in the morning, 25 mg in the afternoon; Day 3: 0.6 mg oral misoprostol. Data on reproductive and demographic characteristics were extracted from clinic records, and complete termination was determined on day 14 (post-mifepristone administration.Results: A total of 337 women underwent early medical abortion (167 WHO- and 170 China-recommended procedures. Complete abortion was significantly higher among women who had the WHO protocol than those who received the China protocol (91.0% vs 77.7%, respectively; P < 0.001. Women using the China-recommended protocol were three times more likely to require an additional dose of misoprostol than women using the WHO protocol (21.8% vs 7.8%, respectively; P < 0.001, and had significantly more bleeding on the day of misoprostol administration (12.5 mL vs 18.5 mL; P < 0.001.Conclusion: This clinical audit provides preliminary evidence suggesting the WHO-recommended protocol may be more effective than the China-recommended protocol for early medical abortion

  15. Women’s perspectives on termination service delivery in Vietnam: a cross-sectional survey in three provinces

    Directory of Open Access Journals (Sweden)

    Ngo TD

    2014-10-01

    Full Text Available Thoai D Ngo,1,2 Caroline Free,1 Hoan T Le,3 Phil Edwards,1 Kiet HT Pham,4 Yen BT Nguyen,4 Thang H Nguyen5 1Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, 2Research, Monitoring, and Evaluation Team, Health System Department, Marie Stopes International, London, UK; 3Department of Environmental Health, Hanoi Medical University, 4Department of Health Economics, Hanoi Medical University, 5Research and Metrics Team, Marie Stopes International Vietnam, Hanoi, Vietnam Objective: To explore the perspectives of abortion service users regarding termination methods and abortion service delivery in Vietnam. Materials and methods: Structured exit interviews were conducted between August and November 2011 with women who underwent termination of pregnancy at 62 public health facilities in Hanoi, Khanh Hoa, and Ho Chi Minh City in Vietnam. All women presenting for termination during the study period were recruited to participate in the study. Following their abortion, women were asked about their perspectives on abortion service delivery and attributes of medical abortion (MA versus manual vacuum aspiration (MVA. Multiple logistic regression was used to assess the association between current method uptake and each attribute. Results: A total of 1,233 women were included in the survey: 541 (43.9% from Hanoi, 163 (13.2% from Khanh Hoa, and 529 (42.9% from Ho Chi Minh: 23.1% underwent MA; 78.9% reported that women should be given a choice between MA and MVA; and 77.6% thought that abortion services were accessible. Among the 48% who responded, 30.1% thought that MA should be made available at primary/secondary health care facilities. Among women who had previously undergone both methods, women who reported that MA "feels more natural" (like a menstrual regulation/period were more likely to choose MA for their current abortion (odds ratio 2.15, 95% confidence interval 1.26–3.69. Conclusion: MA uptake is significantly

  16. Rationale, design, and cohort enrolment of a prospective observational study of the clinical performance of the new contraceptive implant (Femplant in Pakistan

    Directory of Open Access Journals (Sweden)

    Azmat SK

    2014-05-01

    Full Text Available Syed Khurram Azmat,1 Waqas Hameed,1 Anja Lendvay,2 Babar Tasneem Shaikh,3 Ghulam Mustafa,1 Muhammad Ahmed Siddiqui,1 Sajid Brohi,1 Asif Karim,1 Muhammad Ishaque,1 Wajahat Hussain,1 Mohsina Bilgrami,1 Paul J Feldblum2 1Research, Monitoring and Evaluation Department, Marie Stopes Society, Karachi, Pakistan; 2FHI 360, Durham, NC, USA; 3Health Services Academy, Islamabad, Pakistan Introduction: The use of hormonal implants has gained positive traction in family planning programs in recent times. Compared to other popular methods, such as long-term reversible intrauterine devices, the use of hormonal implants as a family planning method has distinct advantages in terms of long-term efficiency and better user compliance and availability. This paper presents a study protocol to document and evaluate the efficacy, safety, and acceptability of Femplant (contraceptive implant in Pakistan during the first year of its use among married women of reproductive age (18–44 years at clinics in two provinces of Pakistan (Sindh and Punjab. Materials and methods: A total of 724 married women were enrolled in a noncomparative prospective observational study. The study involved six government clinics from the Population Welfare Department in Sindh Province and 13 clinics run by the Marie Stopes Society (a local nongovernmental organization in both provinces. The participation of women was subject to voluntary acceptance and medical eligibility. All respondents were interviewed at baseline and subsequently at each scheduled visit during the study period. Side effects, complications and adverse events, if any, were recorded for every participant at each visit to the facility. Discussion: Over the next 5-year period (2013–2018, 27 million hormonal implants will be made available in lower- to middle-income countries by international donors and agencies. The evidence generated from this study will identify factors affecting the acceptability and satisfaction of end

  17. Correlation of Earthquake Locations with Volumetric Source Components in TauTona Gold Mine, South Africa

    Science.gov (United States)

    Kane, D. L.; Boettcher, M. S.

    2013-12-01

    We investigate the source characteristics of earthquakes in TauTona Gold Mine, South Africa, to test if the location of earthquakes relative to mining structures is correlated with significant isotropic source behavior. Earthquakes are well monitored in TauTona Mine, where underground near-source stations record smaller events and higher frequency energy than can generally be observed using surface stations. Our dataset includes -4 mine, including faults, dikes, tunnels, and stopes, are well known from detailed geologic mapping and surveyed mine plans. We use data collected between 2004 and 2009 from the in-mine array (1-6 kHz), the Natural Earthquake Laboratory in South African Mines (NELSAM) project stations (6-12 kHz), and a short-term PASSCAL experiment (200 Hz) to study source mechanism variability and correlation with mapped structures within the mine. Previous studies of earthquakes in mines suggest a relationship between earthquake size and isotropic moment tensor source characteristics. In TauTona Mine, earthquakes with significant implosive source characteristics tend to be infrequent, larger events (Mw > 1.5), whereas earthquakes with significant explosive source characteristics tend to be smaller (Mw closure of tunnels and stopes within the mine, whereas the smallest recorded explosive events can be interpreted as opening cracks that form at the edges of mining structures. Double-couple type sources occur throughout the full magnitude range, and are often located along mapped faults and dikes. We focus our analysis on earthquakes located near the NELSAM stations in the deepest part of the mine, and on earthquakes located at depths greater than the current extent of mining. High precision relative hypocenter relocation performed using the 3-D extensive seismic array provides excellent constraints on location of events. We compute full moment tensor solutions for events using amplitude measurements of individual arrival phases, including nearfield phases

  18. Attributes and perspectives of public providers related to provision of medical abortion at public health facilities in Vietnam: a cross-sectional study in three provinces

    Directory of Open Access Journals (Sweden)

    Ngo TD

    2014-08-01

    Full Text Available Thoai D Ngo,1,2 Caroline Free,1 Hoan T Le,3 Phil Edwards,1 Kiet HT Pham,4 Yen BT Nguyen,4 Thang H Nguyen5 1Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK; 2Research, Monitoring and Evaluation Team, Health System Department, Marie Stopes International, London, UK; 3Department of Environmental Health, 4Department of Health Economics, Hanoi Medical University, 5Research and Metrics Team, Marie Stopes International Vietnam, Hanoi, Vietnam Background: The purpose of this study was to investigate attributes of public service providers associated with the provision of medical abortion in Vietnam. Methods: We conducted a cross-sectional study via interviewer-administered questionnaire among abortion providers from public health facilities in Hanoi, Khanh Hoa, and Ho Chi Minh City in Vietnam between August 2011 and January 2012. We recruited abortion providers at all levels of Vietnam's public health service delivery system. Participants were questioned about their medical abortion provision practices and perspectives regarding abortion methods. Results: A total of 905 providers from 62 health facilities were included, comprising 525 (58.0% from Hanoi, 122 (13.5% from Khanh Hoa, and 258 (28.5% from Ho Chi Minh City. The majority of providers were female (96.7%, aged ≥25 years (94%, married (84.4%, and had at least one child (89%; 68.9% of providers offered only manual vacuum aspiration and 31.1% performed both medical abortion and manual vacuum aspiration. Those performing both methods included physicians (74.5%, midwives (21.7%, and nurses (3.9%. Unadjusted analyses showed that female providers (odds ratio 0.1; 95% confidence interval 0.01–0.30 and providers in rural settings (odds ratio 0.3; 95% confidence interval 0.08–0.79 were less likely to provide medical abortion than their counterparts. Obstetricians and gynecologists were more likely to provide medical abortion than providers with

  19. [Psychiatric aspects in workers subject to mobbing].

    Science.gov (United States)

    Bernabei, A; Gebhardt, Eva; Petrucci, Manuela

    2005-01-01

    Mobbing in the language of ethologists means a particular behaviour of a group of animals consisting of several members forming an alliance against a single animal, in order to eliminate this animal away from the group. This term has been adopted in current usage to mean a kind of relationship at the workplace that, by aggressive and underhand means, aims at influencing or expelling the person. The term "bossing" is used to indicate a negative action, under the meaning described above, made by one or more senior persons, or possibly by the employer. In the Italian Parliament, under the current legislature, several bills are pending regarding this problem. Besides the aspects of topical interest in the problem, there are first and foremost the different kinds of reaction-adaptation to mobbing, according to the type of individual internal working models in action, that can be anxious/avoiding, anxious/resistant or disorganised. The purpose of our study was a clinical evaluation of the different ways of adaptation-reaction to a mobbing-type relationship at the workplace, and of the type of internal working models found among the examined patients. A clinical interview was carried out with 40 patients who, over a period of 12 months of observation, came to request a clinical assessment, for medical-legal reasons, of their psycho-pathological state and ways to react to adverse situations at the workplace, such as a mobbing or bossing. Besides the psychological and relational effects of mobbing, the reactions of the examined subjects to mobbing are also described, considering also the different cognitive self-organization possibilities, according to the individual internal working model, regarding patterns of attachment in adult age. The most frequent internal working model seems to be the one related to resistant attachment, followed by the avoidance and lastly--rarely--the disorganized model. Furthermore we observed among these subjects a certain deficit in meta

  20. ¿QUÉ OCURRE EN EL AULA COSTARRICENSE? LOS NIÑOS Y LAS NIÑAS QUE MALTRATAN A SUS COMPAÑEROS (WHAT HAPPENS IN COSTA RICAN CLASSROOM? CHILDREN ABUSE THEIR PARTNER

    Directory of Open Access Journals (Sweden)

    Pizarro Hannia Cabezas

    2010-12-01

    Full Text Available Resumen:Este artículo es un estudio exploratorio que buscó identificar la presencia de conductas agresivas en escolares costarricenses. Se seleccionó una muestra intencional de 916 estudiantes de 9 a 14 años que cursan de tercero a sexto grado en diversos centros educativos del país, ubicados tanto en zonas rurales como urbanas y se aplicó una encuesta piloto. Del análisis de datos se desprende que un 14.3% de alumnos ha agredido de una u otra forma a sus iguales. Se concluye que la presencia de conductas agresivas en niños en edad escolar en la escuela costarricense es una realidad. De los datos se desprende que un 21% de los estudiantes que agreden a sus iguales son hombres y un 9% son mujeres. Los varones utilizan más la fuerza física y las mujeres acosan a sus iguales de forma solapada. Los datos se analizan porcentualmente en función de la incidencia del criterio que se pretende valorar.Abstract:This article was an exploratory study that seeks to identify the presence of aggressive behavior in Costa Rican school. We selected a purposive sample of 916 students from 9 to 14 years old enrolled in third through sixth grade in various schools in the country, located in both rural and urban areas. This was a pilot survey. Data analysis showed that 14.3% of students have been assaulted in one way or another to their peers. We conclude that the presence of aggressive behavior in school-age children in school in Costa Rica is a reality. Data showed that 21% of students who bully their peers were men and 9% were women. Males used more physical force while women harass their peers in an underhanded way. The data were analyzed based on the percentage incidence of the criteria that is intended to assess.

  1. 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.

  2. 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.

  3. A seismic case study of salt dissolution and subsidence in response to regional deformation, south-central Alberta

    Science.gov (United States)

    Anderson, Neil L.; Williams, R. Shawn; Hinds, Ronald C.

    1996-04-01

    Bedded rock salt with a net thickness of about 40 m was deposited uniformly within the Famennian Wabamun Group in the Stettler South study area (T33-34, R18-21W4M) of south-central Alberta. Subsequent to deposition, this original rock salt was leached to the extent that it is preserved now as irregular-shaped bodies of widely differing areal extent and thickness. In the immediate study area, dissolution was initiated by regional deformation during the mid-Late Cretaceous, and accentuated thereafter by various large-scale processes including glaciation. Seismic data illustrate that at least some salt-dissolution features in the Stettler South area retain a marked linear orientation (SSW-NNE). In cross section (on west-east oriented seismic lines), these structures are manifested as upward-expanding zones of observable subsidence. These zones of subsidence are characterized by increased structural relief at greater depth (resulting principally to the timing of the leaching, stoping, and lateral strain within post-salt strata), and small-amplitude near-vertical offsets. The character of these subsidence features is consistent with: (1) the onset of dissolution as a result of regional deformation during mid-Late Cretaceous; (2) the plastic deformation (creep) of rock salt; (3) the plastic deformation (on a large scale) and relatively gradual subsidence of the post-salt strata; and (4) accelerated rates of leaching in response to glacial loading and unloading.

  4. Backfilling behavior of a mixed aggregate based on construction waste and ultrafine tailings.

    Science.gov (United States)

    Chen, Qiusong; Zhang, Qinli; Xiao, Chongchun; Chen, Xin

    2017-01-01

    To study the possibility of utilizing mixed construction waste and ultrafine tailings (CW&UT) as a backfilling aggregate that can be placed underground in a mine, physicochemical evaluation, proportioning strength tests, and pumpability experiments were conducted. It was revealed that mixed CW&UT can be used as a backfilling aggregate due to the complementarities of their physicochemical properties. In addition, as the results of the proportioning strength tests show, the compressive strength of a cemented CW&UT backfilling specimen cured for 28 days, with a mass fraction of 72-74%, a cement-sand ratio of 1:12, and a CW proportion of 30%, is higher than 1.0 MPa, which meets the safety requirements and economic consideration of backfilling technology in many underground metal mines, and can also be enhanced with an increase in the cement-sand ratio. The results of the pumpability experiments show that cemented backfilling slurry based on CW&UT can be transported to the stope underground with a common filling pump, with a 16.6 MPa maximum pressure, with the condition that the time of emergency shut-down is less than approximately 20 min. All in all, the research to utilize mixed CW&UT as a backfilling aggregate can not only provide a way to dispose of CW&UT but also will bring large economic benefits and can provide constructive guidance for environmental protection.

  5. About the burial of nuclear power plants, damaged or in the process of decommissioning

    International Nuclear Information System (INIS)

    Elbrond, J.

    1994-01-01

    Some underground mining methods leave deep empty holes in the earth's surface behind them. In this paper it is described how to use such mining methods for the burial of damaged nuclear power plants and for the decommissioning by burial of nuclear reactors. The design of a new power plant should be integrated with that of an escapeway - an underground arrangement for burial. The described mining methods are block caving for catastrophy burial, and various stoping methods for planned burial and decommissioning. Blind shaft sinking by full face boring machines for burial and decommissioning of the reactor vessel is also described. All the described activities of mining and shaft sinking are well known. The total costs of burial by these methods are estimated using standard mining industry cost data. These include the costs for normal mine ventilation and groundwater control. However, the estimates of the cost and duration do not include the capital and operational costs of the pre- and post burial activities of ventilation and groundwater control related to the radioactivity. (author)

  6. A study protocol: using demand-side financing to meet the birth spacing needs of the underserved in Punjab Province in Pakistan

    Science.gov (United States)

    2014-01-01

    Background High fertility rates, unwanted pregnancies, low modern contraceptive prevalence and a huge unmet need for contraception adversely affect women’s health in Pakistan and this problem is compounded by limited access to reliable information and quality services regarding birth spacing especially in rural and underserved areas. This paper presents a study protocol that describes an evaluation of a demand-side financing (DSF) voucher approach which aims to increase the uptake of modern contraception among women of the lowest two wealth quintiles in Punjab Province, Pakistan. Methods/Design This study will use quasi-experimental design with control arm and be implemented in: six government clinics from the Population Welfare Department; 24 social franchise facilities branded as ‘Suraj’ (Sun), led by Marie Stopes Society (a local non-governmental organization); and 12 private sector clinics in Chakwal, Mianwali and Bhakkar districts. The study respondents will be interviewed at baseline and endline subject to voluntary acceptance and medical eligibility. In addition, health service data will record each client visit during the study period. Discussion The study will examine the impact of vouchers in terms of increasing the uptake of modern contraception by engaging private and public sector service providers (mid-level and medical doctors). If found effective, this approach can be a viable solution to satisfying the current demand and meeting the unmet need for contraception, particularly among the poorest socio-economic group. PMID:24885657

  7. Elastic waves at periodically-structured surfaces and interfaces of solids

    Directory of Open Access Journals (Sweden)

    A. G. Every

    2014-12-01

    Full Text Available This paper presents a simple treatment of elastic wave scattering at periodically structured surfaces and interfaces of solids, and the existence and nature of surface acoustic waves (SAW and interfacial (IW waves at such structures. Our treatment is embodied in phenomenological models in which the periodicity resides in the boundary conditions. These yield zone folding and band gaps at the boundary of, and within the Brillouin zone. Above the transverse bulk wave threshold, there occur leaky or pseudo-SAW and pseudo-IW, which are attenuated via radiation into the bulk wave continuum. These have a pronounced effect on the transmission and reflection of bulk waves. We provide examples of pseudo-SAW and pseudo-IW for which the coupling to the bulk wave continuum vanishes at isloated points in the dispersion relation. These supersonic guided waves correspond to embedded discrete eigenvalues within a radiation continuum. We stress the generality of the phenomena that are exhibited at widely different scales of length and frequency, and their relevance to situations as diverse as the guiding of seismic waves in mine stopes, the metrology of periodic metal interconnect structures in the semiconductor industry, and elastic wave scattering by an array of coplanar cracks in a solid.

  8. Finnish Official Development Aid for Sexual and Reproductive Health and Rights in Sub-Saharan Africa

    Directory of Open Access Journals (Sweden)

    Riikka Shemeikka

    2010-01-01

    Full Text Available Finland is one of the donor countries that is most supportive in family planning (FP, Sexual and Reproductive Health and Rights (SRHR and gender issues. This study examines Finnish ODA for FP and SRHR: its decision-making structure, other stakeholders and funding levels. Data consists of documents from the Ministry for Foreign Affairs (MFA and interviews conducted at the MFA and with other experts. While Parliament decides on the overall level of ODA funding, the Minister for Foreign Trade and Development has considerable autonomy. Other stakeholders such as the All-Party Parliamentary Group on Population and Development and the Family Federation of Finland (Vestliitto engage in advocacy work and have influenced development policy. Although the Development Policy 2007 mentions the importance of health and SRHR issues and HIV/AIDS is a cross-cutting issue, interviewees stated that the importance of health and SRHR in ODA has declined and that the implementation of cross-cutting issues is challenging. Multilateral funding for UNFPA, UNAIDS and GFATM, and thus the proportion of SRHR funding within the health sector, is however currently rising. Funding for population-related activities has increased and represented 4.8% of Finlands total ODA in 2009. Almost all of this funding is directed towards basic reproductive health and HIV/AIDS issues and the majority is directed through multilateral channels (78% in 2009, mainly UNFPA and UNAIDS. IPPF, Ipas and Marie Stopes International also receive support.

  9. Analysis of radon reduction and ventilation systems in uranium mines in China

    International Nuclear Information System (INIS)

    Hu Penghua; Li Xianjie

    2012-01-01

    Mine ventilation is the most important way of reducing radon in uranium mines. At present, the radon and radon progeny levels in Chinese uranium mines where the cut and fill stoping method is used are 3–5 times higher than those in foreign uranium mines, as there is not much difference in the investments for ventilation protection between Chinese uranium mines and international advanced uranium mines with compaction methodology. In this paper, through the analysis of radon reduction and ventilation systems in Chinese uranium mines and the comparison of advantages and disadvantages between a variety of ventilation systems in terms of radon control, the authors try to illustrate the reasons for the higher radon and radon progeny levels in Chinese uranium mines and put forward some problems in three areas, namely the theory of radon control and ventilation systems, radon reduction ventilation measures and ventilation management. For these problems, this paper puts forward some proposals regarding some aspects, such as strengthening scrutiny, verifying and monitoring the practical situation, making clear ventilation plans, strictly following the mining sequence, promoting training of ventilation staff, enhancing ventilation system management, developing radon reduction ventilation technology, purchasing ventilation equipment as soon as possible in the future, and so on.

  10. The Communities R and D Programme: radioactive waste management and storage

    International Nuclear Information System (INIS)

    1977-01-01

    The European Community's programme is the first and to this date the only joint international action dealing with those issues, which might well become decisive for the future of nuclear energy -the management and storage of radioactive waste. The first Annual Progress Report describes the scope and the state of advancement of this indirect action programme. At present 24 research contracts with research institutes in almost every member country of the EC are either signed or in the final stages of negociation. The objective of the R and D actions to be achieved by 1980 is the demonstration of either the technical potential or, for further advanced projects, the feasibility and even the industrial availability of methods for treating and stoping radwaste. The following aspects are investigated: processing of solid waste from reactors, reprocessing plants and the plutonium manufacture; intermediate and terminal storage of high activity and alpha wastes; advanced waste management methods as the storage of gaseous waste and the separation and transmutation of actinides. In addition to the scientific-technical R and D actions, a survey of the legal, administrative and financial problems encountered in radwaste management and storage is an essential part of the Communities' programme

  11. Analysis of radon reduction and ventilation systems in uranium mines in China.

    Science.gov (United States)

    Hu, Peng-hua; Li, Xian-jie

    2012-09-01

    Mine ventilation is the most important way of reducing radon in uranium mines. At present, the radon and radon progeny levels in Chinese uranium mines where the cut and fill stoping method is used are 3-5 times higher than those in foreign uranium mines, as there is not much difference in the investments for ventilation protection between Chinese uranium mines and international advanced uranium mines with compaction methodology. In this paper, through the analysis of radon reduction and ventilation systems in Chinese uranium mines and the comparison of advantages and disadvantages between a variety of ventilation systems in terms of radon control, the authors try to illustrate the reasons for the higher radon and radon progeny levels in Chinese uranium mines and put forward some problems in three areas, namely the theory of radon control and ventilation systems, radon reduction ventilation measures and ventilation management. For these problems, this paper puts forward some proposals regarding some aspects, such as strengthening scrutiny, verifying and monitoring the practical situation, making clear ventilation plans, strictly following the mining sequence, promoting training of ventilation staff, enhancing ventilation system management, developing radon reduction ventilation technology, purchasing ventilation equipment as soon as possible in the future, and so on.

  12. An Investigation of the Uniaxial Compressive Strength of a Cemented Hydraulic Backfill Made of Alluvial Sand

    Directory of Open Access Journals (Sweden)

    Guangsheng Liu

    2017-01-01

    Full Text Available Backfill is commonly used in underground mines. The quality control of the backfill is a key step to ensure it meets the designed strength requirement. This is done through sample collection from the underground environment, followed by uniaxial compression tests to obtain the Uniaxial Compressive Strength (UCS in the laboratory. When the cylindrical cemented backfill samples are axially loaded to failure, several failure modes can be observed and mainly classified into diagonal shear failure and axial split failure. To date, the UCS obtained by these two failure modes are considered to be the same with no distinction between them. In this paper, an analysis of the UCS results obtained on a cemented hydraulic backfill made of alluvial sand at a Canadian underground mine over the course of more than three years is presented. The results show that the UCS values obtained by diagonal shear failure are generally higher than those obtained by axial split failure for samples with the same recipe and curing time. This highlights the importance of making a distinction between the UCS values obtained by the two different modes of failure. Their difference in failure mechanism is explained. Further investigations on the sources of the data dispersion tend to indicate that the UCS obtained by laboratory tests following the current practice may not be representative of the in-situ strength distribution in the underground stopes due to segregation in cemented hydraulic backfill.

  13. Survey of technological advancement of coal exploitation in Asia and Pacific for fiscal 1997. Formulation of production plans for model coal mines in China; 1997 nendo Asia Taiheiyo sekitan kaihatsu kodoka chosa. Chugoku ni okeru model tanko no seisan keikaku no sakutei

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    In view of the prospective demand for coal in China and of the current state of transportation, a development plan is formulated for Tangkou Mining Area (of model mines) for the purpose of realizing efficient exploitation of coal. The infrastructures for coal transportation are complete in this area, and delivery of coal is easy from this area to the coal demanding regions. Although coal seams are quite deep in the ground, the important ones contain rich reserves. Exploitation is carried out under a vertical shaft scheme, in which pits extend horizontally at the level of 950m below the sea surface. As for production, an annual yield of 3-million ton is predicted thanks to two compositely mechanized coal faces. Coal is won by the monolayer side hole method in the case of seams not thicker than 4.0m, and by the caved stope method in the case not thinner than 4.0m. Employed for the mines are 1077 people. Operation days are 300, efficiency 15t/man/shift. The annual sale in total is expected to be worth 759-million 534.6-thousand yuan. To be required for the construction will be 1.2-billion yuan for mines and 0.2-billion yuan for coal dressing facilities, or 1.4-billion yuan in all, and the figures indicate that the plan is economically promising. 43 figs., 119 tabs.

  14. 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.

  15. Emplacement of the Kodiak batholith and slab-window migration

    Science.gov (United States)

    Farris, David W.; Haeussler, P.; Friedman, R.; Paterson, Scott R.; Saltus, R.W.; Ayuso, R.

    2006-01-01

    The Kodiak batholith is one of the largest, most elongate intrusive bodies in the forearc Sanak-Baranof plutonic belt located in southern Alaska. This belt is interpreted to have formed during the subduction of an oceanic spreading center and the associated migration of a slab window. Individual plutons of the Kodiak batholith track the location and evolution of the underlying slab window. Six U/Pb zircon ages from the axis of the batholith exhibit a northeastward-decreasing age progression of 59.2 ± 0.2 Ma at the southwest end to 58.4 ± 0.2 Ma at the northeast tip. The trench-parallel rate of age progression is within error of the average slab-window migration rate for the entire Sanak-Baranof belt (~19 cm/yr). Structural relationships, U/Pb ages, and a model of new gravity data indicate that magma from the Kodiak batholith ascended 5-10 km as a northeastward-younging series of 1-8-km-diameter viscoelastic diapirs. Individual plutons ascended by multiple emplacement mechanisms including downward flow, collapse of wall rock, stoping, and diking. Stokes flow xenolith calculations suggest ascent rates of 5-100 m/yr and an effective magmatic viscosity of 107-108 Pa s. Pre-existing structural or lithologic heterogeneities did not dominantly control the location of the main batholith. Instead, its location was determined by migration of the slab window at depth. 

  16. SOCIAL FRANCHISING AND SUPPLEMENTARY TUTORING: A QUALITATIVEANALYSIS OFFACILITATORS’PERCEPTIONS

    Directory of Open Access Journals (Sweden)

    Pieter van Schalkwyk

    2017-01-01

    Full Text Available Franchising, a business concept that originated in the United States of America (USA, is asystem of doing business via contracts through which the franchiser shares a system ofknowledge, intellectual property and trade secrets in return for fees and royalties. Socialfranchising, on the other hand, utilises the same principles and format to achieve socialbenefits. Social franchising has been associated with, among others, the health services andeducation. Health services such as Marie Stopes International make use of social franchisingto increase their services by engaging existing private providers to deliver high quality sexualreproductive health services in underserved areas. In education, social franchising can be seenas a quick fix to national problems regarding education. The purpose of this study was toqualitatively analyse facilitators’perceptions of social franchising in education through theprovision of supplementary lessonsand its potential to improvestudents’ performance. Thesample of the study comprised facilitatorsactively involved in the facilitation of lessons tosupplement existing knowledge/impart new learning methodologies in mathematics, scienceand languages for school-going learners. An interview schedulewas developed andparticipants were interviewed at the site of deliveryduring the period when students were onrecess. From a content analysis of the transcripts of the interviewsfour themes, namely,challenges,opportunities,motivationandsustainabilityemerged. It is recommended thatthere should be greater parental as well as university involvement in the provision ofsupplementary tuition for learners. Existing schools with adequate resources should also beconsidered as possible venues for supplementary tuition.

  17. Comprehensive feasibility of raw material projects in small scale mining. An interdisciplinary challenge; Ganzheitliche Machbarkeit von Rohstoffprojekten im Kleinbergbau. Eine interdisziplinaere Herausforderung

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Johannes K.; Bauer, Christian G. [Minccon Geo GmbH, Jenbach (Austria)

    2009-03-15

    For decades now, the geotechnical company Minccon Geo GmbH has been active in the field of mineral development, dressing, processing, stoping and valuation. The following deals particularly with the activities of small scale mining in Central and Eastern Europe and with the practical experiences made. The implementation of successful development and consistent operation of small scale mining presents a challenging and diversified cross-section of the topic. With this definition it is not possible to give a general classification of a mineral enterprise independent of the recovered mineral product, time and space. By way of the jointly organized reference project in the oil shale mining of the Tiroler Steinoelwerke (Austria), the prerequisites for successful project development in small scale mining are presented. The mentioned case studies of the exploration of gold, quartz and clay, show the individual project development, furthermore, the essential researched mineral reserves, the value of the mineral products as well as the investments made for this purpose. Consideration must be given mainly to the limited technical, financial and organisational opportunities of small companies. (orig.)

  18. Efficacy and safety of mifepristone-buccal misoprostol for early medical abortion in an Australian clinical setting.

    Science.gov (United States)

    Goldstone, Philip; Walker, Clara; Hawtin, Katherine

    2017-06-01

    In 2014, a composite pack containing mifepristone-buccal misoprostol, indicated for use to 63 days gestation replaced the existing regimen for early medical abortion (EMA) in Australia. To provide updated efficacy and safety information for the use of mifepristone-buccal misoprostol for EMA in Australia, and assess the effect of patient age and gestational age on efficacy. Observational cohort study of 15 008 women attending one of 16 Marie Stopes International clinics in Australia for an EMA (gestational age ≤ 63 days) between 1 March 2013 and 30 September 2015. Administration of 200 mg oral mifepristone in-clinic was followed 24-48 h later by 800 μg buccal misoprostol self-administered at home. Method success was defined as complete abortion not requiring surgical intervention. Follow-up information was available for 87.14% (13 078/15 008) of women. Likelihood of follow-up was significantly lower for women from rural or remote locations (adjusted odds ratio, 0.47; P misoprostol is an effective and safe alternative to surgical termination of pregnancy up to 63 days gestation. © 2017 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.

  19. Stakeholder perceptions of misoprostol: a qualitative investigation

    Directory of Open Access Journals (Sweden)

    Bazzano AN

    2014-04-01

    Full Text Available Alessandra N Bazzano,1 Lea Jones,1 Thoai D Ngo2 1Department of Global Community Health and Behavioral Sciences, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA; 2Research, Monitoring and Evaluation Team, Health System Department, Marie Stopes International, London, UK Abstract: The study aimed to explore perceptions of stakeholders regarding misoprostol use in Cambodia, a setting with high maternal mortality. Semi-structured expert interviews were conducted with 21 participants in the capital, Phnom Penh. The sample included participants involved in providing reproductive health services through international and local health agencies and the pharmaceutical industry. A theme of controversy over the role of misoprostol in the context of reproductive health services emerged, along with a need to reconcile legitimate viewpoints in order to understand the place of misoprostol in the Cambodian reproductive health setting. Understanding stakeholder perspectives on misoprostol can shed light on the drug's role in reproductive health programming where maternal mortality is high and health facilities are still improving. Keywords: maternal mortality, misoprostol, post-partum hemorrhage, medical abortion, unsafe abortion, Cambodia

  20. Parameters of Solidifying Mixtures Transporting at Underground Ore Mining

    Directory of Open Access Journals (Sweden)

    Golik Vladimir

    2017-01-01

    Full Text Available The article is devoted to the problem of providing mining enterprises with solidifying filling mixtures at underground mining. The results of analytical studies using the data of foreign and domestic practice of solidifying mixtures delivery to stopes are given. On the basis of experimental practice the parameters of transportation of solidifying filling mixtures are given with an increase in their quality due to the effect of vibration in the pipeline. The mechanism of the delivery process and the procedure for determining the parameters of the forced oscillations of the pipeline, the characteristics of the transporting processes, the rigidity of the elastic elements of pipeline section supports and the magnitude of vibrator’ driving force are detailed. It is determined that the quality of solidifying filling mixtures can be increased due to the rational use of technical resources during the transportation of mixtures, and as a result the mixtures are characterized by a more even distribution of the aggregate. The algorithm for calculating the parameters of the pipe vibro-transport of solidifying filling mixtures can be in demand in the design of mineral deposits underground mining technology.

  1. Primary observation of clinical curative effect of superselective uterine artery embolization for treatment of placenta increta

    International Nuclear Information System (INIS)

    Wang Changfu; Zhang Heping; Zhang Hongxia; Jin Haiying; Wang Binjie; He Xiang; Zhang Jie; Li Changbo

    2008-01-01

    Objective: To explore the curative effect on superselective uterine artery embolization for treatment of placenta increta. Methods: Pelvic arteriography was performed to confirm bleeding vessels. Then a 5 F Cobra catheter was inserted superselectively into uterine artery ipsilateral to bleeding, through which methotrexatum (MTX) and gelatin sponge were injected for embolization. After the procedure, bleeding, blood pressure, dischargement of placenta tissue, uterine recuperation, and plasma β-HCG were monitored. Results: Bleeding vessels were confirmed in all of the 5 cases of placenta increta. Uterine artery embolization was successful at sole procedure. The operation time was 25.0 to 60.0 min, with the mean time (37.4 ± 5.8) min. Vaginal bleeding stoped in 3.0 to 12.0 minutes after embolization and the mean time was (5.7 ± 2.4) min. Blood pressure returned to normal after operation and vital signs were stable. Placenta tissue discharged on the 5th day to the 4th week after embolization and the mean time was 17 d. The uterus recuperated and blood β-HCG recovered simutaneously. The menstruation and ovulation during follow-up returned to normal. Conclusion: Superselective uterine artery embolization for treatment of placenta increta has advantages such as short operation time, minimal invasion, definite curative effect and reservation of uterus, which is worthy in clinical application. (authors)

  2. Review of Biohydrometallurgical Metals Extraction from Polymetallic Mineral Resources

    Directory of Open Access Journals (Sweden)

    Helen R. Watling

    2014-12-01

    Full Text Available This review has as its underlying premise the need to become proficient in delivering a suite of element or metal products from polymetallic ores to avoid the predicted exhaustion of key metals in demand in technological societies. Many technologies, proven or still to be developed, will assist in meeting the demands of the next generation for trace and rare metals, potentially including the broader application of biohydrometallurgy for the extraction of multiple metals from low-grade and complex ores. Developed biotechnologies that could be applied are briefly reviewed and some of the difficulties to be overcome highlighted. Examples of the bioleaching of polymetallic mineral resources using different combinations of those technologies are described for polymetallic sulfide concentrates, low-grade sulfide and oxidised ores. Three areas for further research are: (i the development of sophisticated continuous vat bioreactors with additional controls; (ii in situ and in stope bioleaching and the need to solve problems associated with microbial activity in that scenario; and (iii the exploitation of sulfur-oxidising microorganisms that, under specific anaerobic leaching conditions, reduce and solubilise refractory iron(III or manganese(IV compounds containing multiple elements. Finally, with the successful applications of stirred tank bioleaching to a polymetallic tailings dump and heap bioleaching to a polymetallic black schist ore, there is no reason why those proven technologies should not be more widely applied.

  3. Delivering post-abortion care through a community-based reproductive health volunteer programme in Pakistan.

    Science.gov (United States)

    Azmat, Syed Khurram; Shaikh, Babar T; Mustafa, Ghulam; Hameed, Waqas; Bilgrami, Mohsina

    2012-11-01

    This qualitative study was conducted in May-June 2010 with women using post-abortion care (PAC) services provided by the Marie Stopes Society in Pakistan during the six month period preceding the study, more than 70% of whom had been referred to the clinics by reproductive health volunteers (RHVs). The aim of the study was to establish the socio-demographic profile of clients, determine their preferred method of treatment, explore their perceptions of the barriers to accessing post-abortion services and to understand the challenges faced by RHVs. The sample women were selected from six randomly selected districts of Sindh and Punjab. Eight focus group discussions were conducted with PAC clients and fifteen in-depth interviews with RHVs. In addition, a quantitative exit interview questionnaire was administered to 76 clients. Medical, rather than surgical, treatment for incomplete and unsafe abortions was preferred because it was perceived to 'cause less pain', was 'easy to employ' and 'having fewer complications'. Household economics influence women's decision-making on seeking post-abortion care. Other restraining factors include objection by husbands and in-laws, restrictions on female mobility, the views of religious clerics and a lack of transport. The involvement of all stakeholders could secure social approval and acceptance of the provision of safe post-abortion care services in Pakistan, and improve the quality of family planning services to the women who want to space their pregnancies.

  4. Conceptual costing study for the long-term management of the Port Hope area low-level radioactive wastes

    International Nuclear Information System (INIS)

    1989-12-01

    Comparative conceptual cost estimates for several possible options for the long-term management of the Port Hope area low-level radioactive wastes have been developed. Five potentially applicable concepts were considered in the study: shallow land burial, using either unlined trenches, lined trenches or concrete canisters; engineered storage mounds; above-ground concrete vaults; below-ground concrete vaults; and intermediate-depth caverns using either open stopes or shrinkage mining. The objective was to develop comparative estimates. The differences in costs between concepts reflect the differences in handling methodology or costs of additional engineered barriers around the stored waste. An in situ waste volume of 805 000 m 3 , relatively favorable site conditions, a four-year disposal schedule and a consistent costing basis were assumed for each concept. Limited effort was made to optimize specific facility designs or disposal operations. The projected disposal costs vary from $68/m 3 of waste for shallow land burial in unlined trenches, to $312/m 3 of waste disposal in concrete canisters in trenches. The results of this study are reasonably consistent with previous estimates prepared for the low-level Radioactive Waste Management Office

  5. Epigene and Hypogene Gypsum Karst Manifestations of the Castile Formation: Eddy County, New Mexico and Culberson County, Texas, USA

    Directory of Open Access Journals (Sweden)

    Stafford Kevin W.

    2008-07-01

    Full Text Available Permian evaporites of the Castile Formation crop out over ~1,800 km2 in the western Delaware Basin (Eddy County, New Mexico and Culberson County, Texas, USA with abundant and diverse karst manifestations. Epigene karst occurs as well-developed karren on exposed bedrock, while sinkholes dominate the erosional landscape, including both solutional and collapse forms. Sinkhole analyses suggest that more than half of all sinks are the result of upward stoping of subsurface voids, while many solutional sinks are commonly the result of overprinting of collapsed forms. Epigene caves are laterally limited with rapid aperture decreases away from insurgence, with passages developed along fractures and anticline fold axes. Hypogene karst occurs as diverse manifestations, forming the deepest and longest caves within the region as well as abundant zones of brecciation. Hypogene caves exhibit a wide range of morphologies from complex maze and anastomotic patterns to simple, steeply dipping patterns, but all hypogene caves exhibit morphologic features (i.e. risers, outlet cupolas and half-tubes that provide a definitive suite of evidence of dissolution within a mixed convection (forced and free convection hydrologic system. Extensive blanket breccias, abundant breccia pipes and numerous occurrences of calcitized evaporites indicate widespread hypogene speleogenesis throughout the entire Castile Formation. Although most cave and karst development within the Castile outcrop region appears to have hypogene origins, epigene processes areactively overprinting features, creating a complex speleogenetic evolution within the Castile Formation.

  6. Radon problem in uranium industry

    International Nuclear Information System (INIS)

    Khan, A.H.; Raghavayya, M.

    1991-01-01

    Radon emission is invariably associated with the mining and processing of uranium ores. Radon (sup(222)Rn) enters mine atmosphere through diffusion from exposed ore body, fractures and fissures in the rocks and is also brought in by ground water. Being the progenitor of a series of short lived radioisotopes it contributes over 70% of the radiation dose to mine workers and thus accounts for nearly 30% of the total radiation doses received by workers in the whole nuclear industry. This paper summarises the data on radon emanation from the ore body, backfilled sands and mine water. Radon and its progeny concentrations in different haulage levels and stopes of the Jaduguda uranium mine are presented to emphasise the need for a well planned ventilation system to control radiation exposure of miners. Results of radon monitoring from a few exploratory uranium mines are included to indicate the need for a good ventilation system from inception of the mining operations. Relative contribution of mine exhaust and tailings surfaces to the environmental radon are also given. Some instruments developed locally for monitoring of radon and its progeny in mines and in the environment are briefly described to indicate the progress made in this field. (author). 17 refs., 2 figs., 6 tabs

  7. The effect of time-dependent ventilation and radon (thoron) gas emanation rates in underground uranium mines

    International Nuclear Information System (INIS)

    Bigu, J.

    1987-01-01

    A theoretical radiation mine model, suitable for underground uranium mines, has been investigated. In this model, the rate of ventilation and/or the radon (thoron) gas emanation from mine walls are time-dependent. Several cases of practical interest have been investigated including sinusoidal, linear, exponential, stepwise, or a combination of two or more of the above. Analytical solutions were obtained for the time-dependent radon (thoron) gas emanation rate. However, because of the extreme analytical complexity of the solutions corresponding to the time-dependent ventilation rate case, numerical solutions were found using a special Runge-Kutta procedure and the Hamming's modified predictor-corrector method for the solution of linear initial-value problems. The mine model makes provisions for losses of radioactivity, other than by ventilation and radioactive decay, by, say, plate-out on mine walls, and by other mechanisms. Radioactivity data, i.e., radon, thoron, and their progeny, obtained with the above mine model for a number of ventilation and emanation conditions, are presented. Experimental data obtained in an inactive stope of an underground uranium mine for a time-dependent air flow case are shown. Air flow conditions (ventilation rate) were determined by tracer gas techniques using SF 6

  8. Flow and geochemical modeling of drainage from Tomitaka mine, Miyazaki, Japan.

    Science.gov (United States)

    Yamaguchi, Kohei; Tomiyama, Shingo; Metugi, Hideya; Ii, Hiroyuki; Ueda, Akira

    2015-10-01

    The chemistry and flow of water in the abandoned Tomitaka mine of Miyazaki, western Japan were investigated. This mine is located in a non-ferrous metal deposit and acid mine drainage issues from it. The study was undertaken to estimate the quantities of mine drainage that needs to be treated in order to avoid acidification of local rivers, taking into account seasonal variations in rainfall. Numerical models aimed to reproduce observed water levels and fluxes and chemical variations of groundwater and mine drainage. Rock-water interactions that may explain the observed variations in water chemistry are proposed. The results show that: (1) rain water infiltrates into the deeper bedrock through a highly permeable zone formed largely by stopes that are partially filled with spoil from excavations (ore minerals and host rocks); (2) the water becomes acidic (pH from 3 to 4) as dissolved oxygen oxidizes pyrite; (3) along the flow path through the rocks, the redox potential of the water becomes reducing, such that pyrite becomes stable and pH of the mine drainage becomes neutral; and (4) upon leaving the mine, the drainage becomes acidic again due to oxidation of pyrite in the rocks. The present numerical model with considering of the geochemical characteristics can simulate the main variations in groundwater flow and water levels in and around the Tomitaka mine, and apply to the future treatment of the mine drainage. Copyright © 2015. Published by Elsevier B.V.

  9. Spatial Variation and Assessment of Heavy Metal and Radioactive Risk in Farmland around a Retired Uranium Mine

    Science.gov (United States)

    Liang, Jie; Shi, Chen-hao; Zeng, Guang-ming; Zhong, Min-zhou; Yuan, Yu-jie

    2017-07-01

    In recent years, heavy metal contamination in the environment has been attracted worldwide attention due to their toxicity, persistence,extensive sources and non-biodegradable properties. We herein investigate variation trend and risk of heavy metal and radiation distribution in the former mine stope, former mineral ore stockyard, and mine road with surface soils of a retired uranium mine in the mid-south of China. The mean concentrations (mg/kg) of Pb,Cd,Cu,Zn,As,Hg,Cr,Mn,Ni,U, and 232Th were analyzed according to the corresponding background values in Hunan, China. The Geo-accumulation index (Igeo ) were used for the assessment of pollution level of heavy metals and the radioactive elements of U and 232Th. Then, Pollution load index (PLI) and GIS techniquewere integrated to assess spatial distribution of heavy metal contamination and radioactive contamination. Results confirmed that three areas in the retired uranium mine was a primary source of pollution, which showed anthropogenic origin mainly from agricultural runoff, hydrometallurgy from chemical industries, radioactive tailings, and electroplating industriesfinally drained into Zishui River and Xiangjiang River. Based on the actual situation, some suggestions were put forward for the treatment of the retired uranium mine in conclusion.

  10. Uranium-production forecasting: the simulation of a South African gold mine

    International Nuclear Information System (INIS)

    Boydell, D.W.

    1979-01-01

    A computer program is described that estimates the amount of uranium that will be produced from a mine as a co-product of gold subject to a changing economic environment. The program makes use of two models. The first simulates activities underground, whereas the second simulates the performance of processing plant on the surface. The combination of these models generates a description of the flow of ore from stopes and from development, through hoisting, sorting, and the metallurgical plant to the despatch of saleable product. The total production of uranium to the end of the life of the mine constitutes the uranium reserve. The effects on production forecasts and reserve estimates of future trends in cost and price factors are illustrated by results generated from the application of the program to a typical South African mine producing gold and uranium. The graphs presented show that South Africa's future uranium production from underground sources is critically dependent on the gold price in the years ahead. (author)

  11. Ground Support Strategies at the Turquoise Ridge Joint Venture, Nevada

    Science.gov (United States)

    Sandbak, L. A.; Rai, A. R.

    2013-05-01

    Weak rock masses of high grade Carlin-trend gold mineralization are encountered in the Turquoise Ridge Joint Venture underground mine. The sediments consist of very weak and altered limestone, mudstone, and carbon-rich clays. The rock mass ratings are described as very poor to poor (Bieniawski in Proceedings of the symposium on exploration for rock engineering, Johannesburg, South Africa, pp. 97-106, 1976). The undercut and fill or boxes stoping mining methods are used because of the low dipping ore body geometry, complex geology, and weak rock mass. Design criteria are chosen to keep openings in weak rock as small as possible to prevent unraveling and to minimize supplementary support. Typical ground support for drifting includes the use of bolts, mesh, spiling, and shotcrete. Quality control of cemented rock fill (CRF) through sampling and aggregate sieve testing is necessary to insure high support strength. Specific support may include shotcrete arches with steel ring sets and CRF "arches" as a replacement of weak rock masses around long-term mine openings. Movement monitoring is utilized in problem areas and is needed to quantify and validate computer modeling.

  12. Viral Management as a New Type of Enterprise Management in Coal Industry

    Science.gov (United States)

    Garafonova, Olga; Grigashkina, Svetlana; Zhosan, Anna

    2017-11-01

    The article considers the evolution of the concept of "management". The Internet analysis of the concept of "viral management" was conducted, the results of which testify to the positive trend, the growing interest in scientific circles, the relevance of the chosen direction for further research and the increasing popularity of the viral management among business leaders. The indices of coal and brown coal extraction in Ukraine and Russia for 2010-2016 are analyzed. Among the problems that exist in the coal industry are the following: mine assets have a high degree of deterioration; the equipment is rather obsolete and does not correspond to the world level; among the existing face equipment, the specific weight of longwall mining equipment, road headers, loading machines, and belt conveyors of the new generation is only several percent. Five steps of introduction of the virus management at the enterprise are identified: opening, development, participation, diffusion, sustainability. The principles of introduction of the viral management in the enterprises of the coal industry are offered. It is established that the main idea of the viral management is to "infect" the organization and, mainly, employees with one or another "virus" in the form of a common idea or goal. It is indicated that the viral management assumes a certain automaticity of changes, internal "obsession" with this or other innovation, involvement of an informal personal factor.

  13. Strengthening Borehole Configuration from the Retaining Roadway for Greenhouse Gas Reduction: A Case Study

    Science.gov (United States)

    Xue, Fei; Zhang, Nong; Feng, Xiaowei; Zheng, Xigui; Kan, Jiaguang

    2015-01-01

    A monitoring trial was carried out to investigate the effect of boreholes configuration on the stability and gas production rate. These boreholes were drilled from the retaining roadway at longwall mining panel 1111(1) of the Zhuji Coalmine, in China. A borehole camera exploration device and multiple gas parameter measuring device were adopted to monitor the stability and gas production rate. Research results show that boreholes 1~8 with low intensity and thin casing thickness were broken at the depth of 5~10 m along the casing and with a distance of 2~14 m behind the coal face, while boreholes 9~11 with a special thick-walled high-strength oil casing did not fracture during the whole extraction period. The gas extraction volume is closely related to the boreholes stability. After the stability of boreholes 9~11 being improved, the average gas flow rate increased dramatically 16-fold from 0.13 to 2.21 m3/min, and the maximum gas flow rate reached 4.9 m3/min. Strengthening boreholes configuration is demonstrated to be a good option to improve gas extraction effect. These findings can make a significant contribution to the reduction of greenhouse gas emissions from the coal mining industry. PMID:25633368

  14. Strengthening borehole configuration from the retaining roadway for greenhouse gas reduction: a case study.

    Directory of Open Access Journals (Sweden)

    Fei Xue

    Full Text Available A monitoring trial was carried out to investigate the effect of boreholes configuration on the stability and gas production rate. These boreholes were drilled from the retaining roadway at longwall mining panel 1111(1 of the Zhuji Coalmine, in China. A borehole camera exploration device and multiple gas parameter measuring device were adopted to monitor the stability and gas production rate. Research results show that boreholes 1~8 with low intensity and thin casing thickness were broken at the depth of 5~10 m along the casing and with a distance of 2~14 m behind the coal face, while boreholes 9~11 with a special thick-walled high-strength oil casing did not fracture during the whole extraction period. The gas extraction volume is closely related to the boreholes stability. After the stability of boreholes 9~11 being improved, the average gas flow rate increased dramatically 16-fold from 0.13 to 2.21 m3/min, and the maximum gas flow rate reached 4.9 m3/min. Strengthening boreholes configuration is demonstrated to be a good option to improve gas extraction effect. These findings can make a significant contribution to the reduction of greenhouse gas emissions from the coal mining industry.

  15. Viral Management as a New Type of Enterprise Management in Coal Industry

    Directory of Open Access Journals (Sweden)

    Garafonova Olga

    2017-01-01

    Full Text Available The article considers the evolution of the concept of “management”. The Internet analysis of the concept of “viral management” was conducted, the results of which testify to the positive trend, the growing interest in scientific circles, the relevance of the chosen direction for further research and the increasing popularity of the viral management among business leaders. The indices of coal and brown coal extraction in Ukraine and Russia for 2010-2016 are analyzed. Among the problems that exist in the coal industry are the following: mine assets have a high degree of deterioration; the equipment is rather obsolete and does not correspond to the world level; among the existing face equipment, the specific weight of longwall mining equipment, road headers, loading machines, and belt conveyors of the new generation is only several percent. Five steps of introduction of the virus management at the enterprise are identified: opening, development, participation, diffusion, sustainability. The principles of introduction of the viral management in the enterprises of the coal industry are offered. It is established that the main idea of the viral management is to “infect” the organization and, mainly, employees with one or another “virus” in the form of a common idea or goal. It is indicated that the viral management assumes a certain automaticity of changes, internal “obsession” with this or other innovation, involvement of an informal personal factor.

  16. Angles of total shifts and angles of maxumum crop during development of faces diagonal to seam strike directions

    Directory of Open Access Journals (Sweden)

    Н. А. Колесник

    2017-06-01

    Full Text Available When predicting deformations and determining measures to protect underworked objects, angular parameters are used: the boundary angles, the angles of total shift, the angle of maximum crop. The values of these angular parameters are given in the normative documents, but only for sections across and along the strike of the formation. However, at present, longwall face mining is mainly being carried out along a diagonal direction to the strike of the formation. In connection with this, the determination of the values of the angular parameters for such conditions is a topical task.The method of determination and the analytical dependences of the angles of total shifts and angles of maximum crop in sections of the longitudinal and transverse axes of coal-mining faces developed along diagonal directions to the strike of the formation are proposed. These angular parameters are used for prognosis of deformations of the earth's surface and for determining the characteristic zones of influence of mine workings on the local places.

  17. Possibility of using the smoothed spline functions in approximation of average course of terrain inclinations caused by underground mining exploitation conducted at medium depth

    Science.gov (United States)

    Orwat, J.

    2018-01-01

    In this paper was presented an obtainment way of the average values of terrain inclinations caused by an exploitation of the 338/2 coal bed, conducted at medium depth by four longwalls. The inclinations were measured at sections of measuring line established over the excavations, perpendicularly to their runways, after the termination of subsequent exploitation stages. The average courses of measured inclinations were calculated on the basis of average values of measured subsidence obtained as a result of an average-square approximation done by the use of smooth splines, in reference to their theoretical values calculated via the S. Knothe’s and J. Bialek’s formulas. The typical values of parameters of these formulas were used. Thus it was obtained for two average courses after the ending of each exploitation period. The values of standard deviations between average and measured inclinations σI and variability coefficients of random scattering of inclinations MI were calculated. Then they were compared with the values appearing in the literature and based on this the possibility evaluation of use smooth splines to determination of average course of observed inclinations of mining area was conducted.

  18. The impact of changes in the rheological parameters of fine-grained hydromixtures on the efficiency of a selected industrial gravitational hydraulic transport system

    Science.gov (United States)

    Popczyk, Marcin

    2017-11-01

    Polish hard coal mines commonly use hydromixtures in their fire prevention practices. The mixtures are usually prepared based on mass-produced power production wastes, namely the ashes resulting from power production [1]. Such hydromixtures are introduced to the caving area which is formed due to the advancement of a longwall. The first part of the article presents theoretical fundamentals of determining the parameters of gravitational hydraulic transport of water and ash hydromixtures used in the mining pipeline systems. Each hydromixture produced based on fine-grained wastes is characterized by specified rheological parameters that have a direct impact on the future flow parameters of a given pipeline system. Additionally, the gravitational character of the hydraulic transport generates certain limitations concerning the so-called correct hydraulic profile of the system in relation to the applied hydromixture characterized by required rheological parameters that should ensure safe flow at a correct efficiency [2]. The paper includes an example of a gravitational hydraulic transport system and an assessment of the correctness of its hydraulic profile as well as the assessment of the impact of rheological parameters of fine-grained hydromixtures (water and ash) produced based on laboratory tests, depending on the specified flow parameters (efficiency) of the hydromixture in the analyzed system.

  19. Twentieth anniversary of the fusion of the Wanda-Lech and Pokoj mines at Ruda Slaska

    Energy Technology Data Exchange (ETDEWEB)

    Pisarek, P.; Baranowski, Z.; Maczka, a.; Kowalski, Z.

    1988-10-01

    Presents the history of the Wanda-Lech and Pokoj mines until 1968 when they were fused, and development, technical progress and investment in the mines since 1968. Application of longwall equipment sets dates from 1965. The index of powered winning has reached 93.7% and that of powered loading - 97.4%. Seismoacoustic (1970/71) and microseismologic (1974) monitoring stations have been put into operation. The following investments have been realized since 1968: the main shaft Wanda and auxiliary shaft Lech II, two winning horizons, 3 main ventilation fans, a coal preparation plant, a bathhouse for 2,650 and a boiler house fuelled with run-of-mine methane. Mine communications, rail transport and storage facilitites have been modernized and extended. The mining area of the present Pokoj mine is shown in a scheme. Production before and after the take-over is compared: production increased from 1.969121 Mt in 1968 to 2.434740 Mt in 1987. A rehabilitation center (physical therapy, inhalation kinesthesia, hydrotherapy) cares for 2,000 patients annually. Further social services and facilities provided for the miners are described.

  20. Coal production, 1991

    International Nuclear Information System (INIS)

    1992-10-01

    Coal production in the United States in 1991 declined to a total of 996 million short tons, ending the 6-year upward trend in coal production that began in 1985. The 1991 figure is 33 million short tons below the record level of 1.029 billion short tons produced in 1990 (Table 1). Tables 2 through 33 in this report include data from mining operations that produced, prepared, and processed 10,000 or more short tons during the year. These mines yielded 993 million short tons, or 99.7 percent of the total coal production in 1991, and their summary statistics are discussed below. The majority of US coal (587 million short tons) was produced by surface mining (Table 2). Over half of all US surface mine production occurred in the Western Region, though the 60 surface mines in this area accounted for only 5 percent of the total US surface mines. The high share of production was due to the very large surface mines in Wyoming, Texas and Montana. Nearly three quarters of underground production was in the Appalachian Region, which accounted for 92 percent of underground mines. Continuous mining methods produced the most coal among those underground operations that responded. Of the 406 million short tons, 59 percent (239 million short tons) was produced by continuous mining methods, followed by longwall (29 percent, or 119 million short tons), and conventional methods (11 percent, or 46 million short tons)

  1. Integrated coal preparation

    International Nuclear Information System (INIS)

    Buchanan, D.J.; Jones, T.F.

    1992-01-01

    Perceptions of quality have changed over the years. The attributes of a certain coal (its rank, slagging propensity, ash content etc) are traditionally referred to as its quality. However, the subject of this paper is quality in a much wider sense: quality as fitness for purpose: and all that such a wide definition entails. British Standard BS 5750 (ISO 9000) Quality Systems defines a systems approach to quality, and includes both the supplier of raw materials and the final customer within this boundary. Coal preparation starts at the production face. The greater the proportion of dirt in run-of-mine product the greater the challenge in satisfying the customer's needs. Significant advances have been made in minimizing mined dirt. For example, the sue of vertical steering on longwall faces improves productivity and quality. Unfortunately modern mining methods produce large quantities of fines, despite efforts to reduce them at the point of production and during transportation to the surface. Coal preparation also produces further fines. It has been estimated that fine coal costs 2.5 times as much to clean as large coal, and the costs of handing wet fine coal product will inflate this estimate. Handling considerations rightly concern our customers and are part of the wider meaning of quality. In this paper the authors address some novel solutions to the challenge posed by fines

  2. Review of potential subsurface permeable barrier emplacement and monitoring technologies

    Energy Technology Data Exchange (ETDEWEB)

    Riggsbee, W.H.; Treat, R.L.; Stansfield, H.J.; Schwarz, R.M. [Ebasco Environmental, Richland, WA (United States); Cantrell, K.J. [Pacific Northwest Lab., Richland, WA (United States); Phillips, S.J. [Westinghouse Hanford Co., Richland, WA (United States)

    1994-02-01

    This report focuses on subsurface permeable barrier technologies potentially applicable to existing waste disposal sites. This report describes candidate subsurface permeable barriers, methods for emplacing these barriers, and methods used to monitor the barrier performance. Two types of subsurface barrier systems are described: those that apply to contamination.in the unsaturated zone, and those that apply to groundwater and to mobile contamination near the groundwater table. These barriers may be emplaced either horizontally or vertically depending on waste and site characteristics. Materials for creating permeable subsurface barriers are emplaced using one of three basic methods: injection, in situ mechanical mixing, or excavation-insertion. Injection is the emplacement of dissolved reagents or colloidal suspensions into the soil at elevated pressures. In situ mechanical mixing is the physical blending of the soil and the barrier material underground. Excavation-insertion is the removal of a soil volume and adding barrier materials to the space created. Major vertical barrier emplacement technologies include trenching-backfilling; slurry trenching; and vertical drilling and injection, including boring (earth augering), cable tool drilling, rotary drilling, sonic drilling, jetting methods, injection-mixing in drilled holes, and deep soil mixing. Major horizontal barrier emplacement technologies include horizontal drilling, microtunneling, compaction boring, horizontal emplacement, longwall mining, hydraulic fracturing, and jetting methods.

  3. Modelling of strata movement with a special reference to caving mechanism in thick seam coal mining

    Energy Technology Data Exchange (ETDEWEB)

    Unver, B.; Yasitli, N.E. [Hacettepe University, Department of Mining Engineering, Beytepe 06532, Ankara (Turkey)

    2006-04-03

    Caving of top coal behind the face is the key factor affecting the efficiency of production at thick coal seams. During production of top coal by caving behind the face not only is a significant amount of coal lost in the goaf but also the coal drawn by means of caving is usually diluted considerably with surrounding rock. Therefore, it is not possible to carry out an efficient production operation unless caving of top coal behind the face is optimized. In this paper, results of 3-D modelling of the top coal caving mechanism at the M3 longwall panel of Omerler Underground Mine located at Tuncbilek (Turkey) are presented by using a finite difference code called FLAC{sup 3D}. According to modelling results, a 1.5-2.0-m-thick layer of coal just above the shield supports is well fractured. However, 3.0-3.5-m-thick layer of coal above the well-fractured part is either not fractured or fractured in the form of large blocks leading to obstruction of windows of shields during coal drawing. It is concluded that, in order to decrease dilution and increase extraction ratio and production efficiency, the top coal should be as uniformly fractured as much as possible. Hence, an efficient and continuous coal flowing behind the face can be maintained. A special pre-fracture blasting strategy just sufficient enough to form cracks in the top coal is suggested by means of comparing results from numerical modelling. (author)

  4. Time-dependent seismic hazard in Bobrek coal mine, Poland, assuming different magnitude distribution estimations

    Science.gov (United States)

    Leptokaropoulos, Konstantinos; Staszek, Monika; Cielesta, Szymon; Urban, Paweł; Olszewska, Dorota; Lizurek, Grzegorz

    2017-06-01

    The purpose of this study is to evaluate seismic hazard parameters in connection with the evolution of mining operations and seismic activity. The time-dependent hazard parameters to be estimated are activity rate, Gutenberg-Richter b-value, mean return period and exceedance probability of a prescribed magnitude for selected time windows related with the advance of the mining front. Four magnitude distribution estimation methods are applied and the results obtained from each one are compared with each other. Those approaches are maximum likelihood using the unbounded and upper bounded Gutenberg-Richter law and the non-parametric unbounded and non-parametric upper-bounded kernel estimation of magnitude distribution. The method is applied for seismicity occurred in the longwall mining of panel 3 in coal seam 503 in Bobrek colliery in Upper Silesia Coal Basin, Poland, during 2009-2010. Applications are performed in the recently established Web-Platform for Anthropogenic Seismicity Research, available at https://tcs.ah-epos.eu/.

  5. On-Site Radon Detection of Mining-induced Fractures from Overlying Strata to the Surface: A Case Study of the Baoshan Coal Mine in China

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    2014-12-01

    Full Text Available Large-scale longwall mining of shallow coal seams may cause mining-induced fractures that can project completely through to the surface. This could lead to a series of mine safety and environmental issues, further deteriorating the already fragile ecological environment in the Western mining areas in China. Therefore, an accurate and effective understanding of the spatiotemporal evolution law of mining-induced fractures in overlying strata and its relationship to upper aquifers is critical. In this paper, the application of the geophysical-chemical properties of radon in mining engineering is explored as a potential solution to the shortcomings of existing surveying methods. A radioactive measurement method is proposed for the detection of the development of mining-induced fractures from overlying strata to the surface in the Baoshan Coal Mine (BCM. The on-site test indicated that the first weighting step is approximately 60 m, the average periodic weighting step is approximately 20 m, and the influence coverage of the advanced abutment pressure is approximately 30 m. The presented method could be used as an indirect technical support to increase the safety of coal mining by acting as a simple, fast, and reliable method of detecting mining-induced fractures in overlying strata.

  6. The possibility of increasing the efficiency of accessible coal deposits by optimizing dimensions of protective pillars or the scope of exploitation

    Science.gov (United States)

    Bańka, Piotr; Badura, Henryk; Wesołowski, Marek

    2017-11-01

    One of the ways to protect objects exposed to the influences of mining exploitation is establishing protective pillars for them. Properly determined pillar provides effective protection of the object for which it was established. Determining correct dimensions of a pillar requires taking into account contradictory requirements. Protection measures against the excessive influences of mining exploitation require designing the largest possible pillars, whereas economic requirements suggest a maximum reduction of the size of resources left in the pillar. This paper presents algorithms and programs developed for determining optimal dimensions of protective pillars for surface objects and shafts. The issue of designing a protective pillar was treated as a nonlinear programming task. The objective function are the resources left in a pillar while nonlinear limitations are the deformation values evoked by the mining exploitation. Resources in the pillar may be weighted e.g. by calorific value or by the inverse of output costs. The possibility of designing pillars of any polygon shape was taken into account. Because of the applied exploitation technologies the rectangular pillar shape should be considered more advantageous than the oval one, though it does not ensure the minimization of resources left in a pillar. In this article there is also presented a different approach to the design of protective pillars, which instead of fixing the pillar boundaries in subsequent seams, the length of longwall panels of the designed mining exploitation is limited in a way that ensures the effective protection of an object while maximizing the extraction ratio of the deposit.

  7. Geomechanics of subsidence above single and multi-seam coal mining

    Directory of Open Access Journals (Sweden)

    A.M. Suchowerska Iwanec

    2016-06-01

    Full Text Available Accurate prediction of surface subsidence due to the extraction of underground coal seams is a significant challenge in geotechnical engineering. This task is further compounded by the growing trend for coal to be extracted from seams either above or below previously extracted coal seams, a practice known as multi-seam mining. In order to accurately predict the subsidence above single and multi-seam longwall panels using numerical methods, constitutive laws need to appropriately represent the mechanical behaviour of coal measure strata. The choice of the most appropriate model is not always straightforward. This paper compares predictions of surface subsidence obtained using the finite element method, considering a range of well-known constitutive models. The results show that more sophisticated and numerically taxing constitutive laws do not necessarily lead to more accurate predictions of subsidence when compared to field measurements. The advantages and limitations of using each particular constitutive law are discussed. A comparison of the numerical predictions and field measurements of surface subsidence is also provided.

  8. Use of IT platform in determination of efficiency of mining machines

    Science.gov (United States)

    Brodny, Jarosław; Tutak, Magdalena

    2018-01-01

    Determination of effective use of mining devices has very significant meaning for mining enterprises. High costs of their purchase and tenancy cause that these enterprises tend to the best use of possessed technical potential. However, specifics of mining production causes that this process not always proceeds without interferences. Practical experiences show that determination of objective measure of utilization of machine in mining enterprise is not simple. In the paper a proposition for solution of this problem is presented. For this purpose an IT platform and overall efficiency model OEE were used. This model enables to evaluate the machine in a range of its availability performance and quality of product, and constitutes a quantitative tool of TPM strategy. Adapted to the specificity of mining branch the OEE model together with acquired data from industrial automatic system enabled to determine the partial indicators and overall efficiency of tested machines. Studies were performed for a set of machines directly use in coal exploitation process. They were: longwall-shearer and armoured face conveyor, and beam stage loader. Obtained results clearly indicate that degree of use of machines by mining enterprises are unsatisfactory. Use of IT platforms will significantly facilitate the process of registration, archiving and analytical processing of the acquired data. In the paper there is presented methodology of determination of partial indices and total OEE together with a practical example of its application for investigated machines set. Also IT platform was characterized for its construction, function and application.

  9. Numerical Approach for Goaf-Side Entry Layout and Yield Pillar Design in Fractured Ground Conditions

    Science.gov (United States)

    Jiang, Lishuai; Zhang, Peipeng; Chen, Lianjun; Hao, Zhen; Sainoki, Atsushi; Mitri, Hani S.; Wang, Qingbiao

    2017-11-01

    Entry driven along goaf-side (EDG), which is the development of an entry of the next longwall panel along the goaf-side and the isolation of the entry from the goaf with a small-width yield pillar, has been widely employed in China over the past several decades . The width of such a yield pillar has a crucial effect on EDG layout in terms of the ground control, isolation effect and resource recovery rate. Based on a case study, this paper presents an approach for evaluating, designing and optimizing EDG and yield pillar by considering the results from numerical simulations and field practice. To rigorously analyze the ground stability, the numerical study begins with the simulation of goaf-side stress and ground conditions. Four global models with identical conditions, except for the width of the yield pillar, are built, and the effect of pillar width on ground stability is investigated by comparing aspects of stress distribution, failure propagation, and displacement evolution during the entire service life of the entry. Based on simulation results, the isolation effect of the pillar acquired from field practice is also considered. The suggested optimal yield pillar design is validated using a field test in the same mine. Thus, the presented numerical approach provides references and can be utilized for the evaluation, design and optimization of EDG and yield pillars under similar geological and geotechnical circumstances.

  10. Study of Coal Burst Source Locations in the Velenje Colliery

    Directory of Open Access Journals (Sweden)

    Goran Vižintin

    2016-06-01

    Full Text Available The Velenje coal mine (VCM is situated on the largest Slovenian coal deposit and in one of the thickest layers of coal known in the world. The thickness of the coal layer causes problems for the efficiency of extraction, since the majority of mining operations is within the coal layer. The selected longwall coal mining method with specific geometry, increasing depth of excavations, changes in stress state and naturally given geomechanical properties of rocks induce seismic events. Induced seismic events can be caused by caving processes, blasting or bursts of coal or the surrounding rock. For 2.5D visualization, data of excavations, ash content and calorific value of coal samples, hanging wall and footwall occurrence, subsidence of the surface and coal burst source locations were collected. Data and interpolation methods available in software package Surfer®12 were statistically analyzed and a Kriging (KRG interpolation method was chosen. As a result 2.5D visualizations of coal bursts source locations with geomechanical properties of coal samples taken at different depth in the coal seam in the VCM were made with data-visualization packages Surfer®12 and Voxler®3.

  11. Impact of type of the roof rocks on location and range of endogenous fires particular hazard zone by in goaf with caving

    Science.gov (United States)

    Tutak, Magdalena; Brodny, Jarosław

    2018-01-01

    Hazard of endogenous fires is one of the basic and common presented occupational safety hazards in coal mine in Poland and in the world. This hazard means possibility of coal self-ignition as the result of its self-heating process in mining heading or its surrounding. In underground coal-mining during ventilating of operating longwalls takes place migration of parts of airflow to goaf with caving. In a case when in these goaf a coal susceptible to self-ignition occurs, then the airflow through these goaf may influence on formation of favorable conditions for coal oxidation and subsequently to its self-heating and self-ignition. Endogenous fire formed in such conditions can pose a serious hazards for the crew and for continuity of operation of mining plant. From the practical point of view a very significant meaning has determination of the zone in the goaf with caving, in which necessary conditions for occurence of endogenous fire are fulfilled. In the real conditions determination of such a zone is practically impossible. The main aim of the analysis was to determine the impact of type of the roof rocks forming the goaf on the location and range of endogenous fires particular hazard zone by in these goaf. For determined mining-geological conditions, the critical value of velocity of airflow and oxygen concentration in goaf, conditioning initiation of coal oxidation process were determined.

  12. Geomechanical behaviour of laminated, weak coal mine roof strata and the implications for a ground reinforcement strategy

    Energy Technology Data Exchange (ETDEWEB)

    Hebblewhite, B.K.; Lu, T. [University of New South Wales, Sydney, NSW (Australia). School of Mining Engineering

    2004-01-01

    This paper describes a component of the results from an ARC-SPIRT funded collaborative research project between UNSW, Powercoal Pty Ltd. and Springvale Coal Pty Ltd. The research project was aimed at identifying strategies for appropriate ground control in particularly weak and soft roof strata in underground coal mining. A field investigation was undertaken at Angus Place Colliery in the Western Coalfield of New South Wales. The investigation incorporated a range of geotechnical instrumentation and was conducted over a period of time from the development face until the site was lost into the goaf of a retreating longwall panel. This paper describes the outcomes from the field investigation, together with a selection of supporting laboratory studies. The paper also presents a number of alternative presentation modes for extensometry data. The results clearly demonstrate the time and face-proximity related influences on roof integrity, and particularly demonstrated the distribution of deformation, bed separation and strata failure into the roof and across the full span of the roadway, together with reflection of this behaviour within the fully encapsulated roof bolt reinforcement system installed.

  13. The Development of Dewatering Predictions of the Velenje Coalmine

    Directory of Open Access Journals (Sweden)

    Željko Vukelić

    2016-08-01

    Full Text Available The complex hydro-geological situation, particularly in terms of groundwater, has been a constant threat to the mining carried out at the Velenje colliery since its inception. Of particular interest to the authors are the difficulties presented to the colliery by the adjacent sand aquifers, as the water pressure within these sands directly impacts mining safety, and the aquifers themselves are most directly affected by dewatering. In order to monitor water levels and estimate dewatering at the Velenje wells, multi-layered modelling using 3D Finite Difference Method (FDM has already been carried out. However, FDM is not optimal due to its greater dependence on cell size than on water flow. In 2017 in Velenje, a series of wells will be terminated as a result of mining and mining-induced subsidence, leading to dewatering and danger of flooding. As part of a plan to address this by replacing dewatering structures, a series of drive-in filters will be implemented around the entry and exit point tunnels of a longwall face. Because FDM seems to be inadequate for purposes of optimising this process, the Finite Elements Method (FEM was applied in this case. Based on such an application of FEM, a prediction of the optimisation of drive-in filters was carried out by the authors.

  14. Origin of acid mine drainage in Enugu

    International Nuclear Information System (INIS)

    Uma, K.O.

    1992-01-01

    Mine flooding is a serious problem in the Enugu Coal Mines and has led to the abandonment of two of the four mines. About 1800 m 3 of water is pumped out daily from the mines into the nearby streams. The source of this enormous volume of water has been established based on the hydrodynamics and hydrology of the area. Two prolific aquifers - an unconfined and a confined system - overlie the mines, but the mine water is derived principally from the unconfined aquifer. The pathway of flow is, provided by the numerous fractures connecting the two aquifers and the mine tunnel. The major hydrochemical activity resulting in pollution of the mine water occurs within the sumps in the floor of the longwalls. These sumps act as oxidation chambers where groundwater from the fractures mixes and subsequently reacts with sulfur-rich solutes released by coal mining. Contrary to general belief, the mine drainage has not seriously degraded the chemistry of receiving streams. The pH and electric conductivity, representing, the dissolved ions, were increased less than 10% of the values in the unaffected region

  15. Review of potential subsurface permeable barrier emplacement and monitoring technologies

    International Nuclear Information System (INIS)

    Riggsbee, W.H.; Treat, R.L.; Stansfield, H.J.; Schwarz, R.M.; Cantrell, K.J.; Phillips, S.J.

    1994-02-01

    This report focuses on subsurface permeable barrier technologies potentially applicable to existing waste disposal sites. This report describes candidate subsurface permeable barriers, methods for emplacing these barriers, and methods used to monitor the barrier performance. Two types of subsurface barrier systems are described: those that apply to contamination.in the unsaturated zone, and those that apply to groundwater and to mobile contamination near the groundwater table. These barriers may be emplaced either horizontally or vertically depending on waste and site characteristics. Materials for creating permeable subsurface barriers are emplaced using one of three basic methods: injection, in situ mechanical mixing, or excavation-insertion. Injection is the emplacement of dissolved reagents or colloidal suspensions into the soil at elevated pressures. In situ mechanical mixing is the physical blending of the soil and the barrier material underground. Excavation-insertion is the removal of a soil volume and adding barrier materials to the space created. Major vertical barrier emplacement technologies include trenching-backfilling; slurry trenching; and vertical drilling and injection, including boring (earth augering), cable tool drilling, rotary drilling, sonic drilling, jetting methods, injection-mixing in drilled holes, and deep soil mixing. Major horizontal barrier emplacement technologies include horizontal drilling, microtunneling, compaction boring, horizontal emplacement, longwall mining, hydraulic fracturing, and jetting methods

  16. Pelletization of fine coals. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Sastry, K.V.S.

    1995-12-31

    Coal is one of the most abundant energy resources in the US with nearly 800 million tons of it being mined annually. Process and environmental demands for low-ash, low-sulfur coals and economic constraints for high productivity are leading the coal industry to use such modern mining methods as longwall mining and such newer coal processing techniques as froth flotation, oil agglomeration, chemical cleaning and synthetic fuel production. All these processes are faced with one common problem area--fine coals. Dealing effectively with these fine coals during handling, storage, transportation, and/or processing continues to be a challenge facing the industry. Agglomeration by the unit operation of pelletization consists of tumbling moist fines in drums or discs. Past experimental work and limited commercial practice have shown that pelletization can alleviate the problems associated with fine coals. However, it was recognized that there exists a serious need for delineating the fundamental principles of fine coal pelletization. Accordingly, a research program has been carried involving four specific topics: (i) experimental investigation of coal pelletization kinetics, (ii) understanding the surface principles of coal pelletization, (iii) modeling of coal pelletization processes, and (iv) simulation of fine coal pelletization circuits. This report summarizes the major findings and provides relevant details of the research effort.

  17. Review of subsidence and stabilization techniques

    International Nuclear Information System (INIS)

    Fernando, D.A.

    1988-01-01

    In Britain the damage caused by underground coal mining operations approximates to about 100 million pounds Sterling per annum, most of the damage resulting from longwall mining operations. Causes of subsidence can be attributed to the following factors: (1) roof failure (2) pillar failure (3) floor movements. Currently, in Britain, the mining industry is undergoing a state of decline for economic reasons. Consequently, the number of old coal sites available for development schemes has increased. Therefore, the problems associated with subsidence can be segregated into two parts. The first being the mitigation of the effects of subsidence on structures on actively mined areas. The second being the stabilization and rehabilitation of ground over and around old mine sites for new development schemes. In the former case the stabilization techniques employed may be local or global, depending on the problems encountered in any particular area. In the latter case, generally, grouting techniques are employed. This paper aims to review the causes of subsidence and the techniques used to minimize its effect on structures. Also, more economic alternative methods of ground stabilization techniques are described and proposed, to be used in this area of ground engineering

  18. Average course approximation of measured subsidence and inclinations of mining area by smooth splines

    Directory of Open Access Journals (Sweden)

    Justyna Orwat

    2017-01-01

    Full Text Available The results of marking average courses of subsidence measured on the points of measuring line no. 1 of the “Budryk” Hard Coal Mine, set approximately perpendicularly to a face run of four consecutively mined longwalls in coal bed 338/2 have been presented in the article. Smooth splines were used to approximate the average course of measured subsidence after subsequent exploitation stages. The minimising of the sum of the squared differences between the average and forecasted subsidence, using J. Bialek's formula, was used as a selection criterion of parameter values of smoothing an approximating function. The parameter values of this formula have been chosen in order to match forecasted subsidence with measured ones. The average values of inclinations have been calculated on the basis of approximated values of observed subsidence. It has been shown that by doing this the average values of extreme measured inclinations can be obtained in almost the same way as extreme observed inclinations. It is not necessary to divide the whole profile of a subsidence basin into parts. The obtained values of variability coefficients of a random scattering for subsidence and inclinations are smaller than their values which occur in the literature.

  19. Damages to the roadway tunnels in the coal mining area of Hebi, P.R. China: proposals to minimise damages and numerical analysis

    International Nuclear Information System (INIS)

    Fuchsberger, M.; Schweiger, H.F.

    1997-01-01

    The influence of a coal mining operation on the roadways constructed in the underlying rock strata is generally well known. In a joint research project between CCMRI (Beijing) and the Technical University Graz (Austria) the frequent damage to the roadways in the Hebi mining area resulting from the longwall mining operation of the overlying coal-seam were investigated. The likely cause of the damage was established and proposals were made to improve the tunnel performance by a modification of the cross-sectional geometry and of the driving operation of the tunnels whereby the principles of the New Austrian Tunnelling Method (NATM) were employed. The aim was to minimise or to avoid the damages caused by the mining operation and thus reduce the high cost of constant repairs. A well instrumented test section of the modified tunnel was constructed and its performance during the ensuing coal extraction was monitored. The paper describes the initial investigations, the NATM proposals, as well as a brief description and the interpretation of a FEM analysis made in this connection. 6 refs., 11 figs., 1 tab

  20. VRLane: a desktop virtual safety management program for underground coal mine

    Science.gov (United States)

    Li, Mei; Chen, Jingzhu; Xiong, Wei; Zhang, Pengpeng; Wu, Daozheng

    2008-10-01

    VR technologies, which generate immersive, interactive, and three-dimensional (3D) environments, are seldom applied to coal mine safety work management. In this paper, a new method that combined the VR technologies with underground mine safety management system was explored. A desktop virtual safety management program for underground coal mine, called VRLane, was developed. The paper mainly concerned about the current research advance in VR, system design, key techniques and system application. Two important techniques were introduced in the paper. Firstly, an algorithm was designed and implemented, with which the 3D laneway models and equipment models can be built on the basis of the latest mine 2D drawings automatically, whereas common VR programs established 3D environment by using 3DS Max or the other 3D modeling software packages with which laneway models were built manually and laboriously. Secondly, VRLane realized system integration with underground industrial automation. VRLane not only described a realistic 3D laneway environment, but also described the status of the coal mining, with functions of displaying the run states and related parameters of equipment, per-alarming the abnormal mining events, and animating mine cars, mine workers, or long-wall shearers. The system, with advantages of cheap, dynamic, easy to maintenance, provided a useful tool for safety production management in coal mine.

  1. Continuous monitoring of mining induced strain in a road pavement using fibre Bragg grating sensors

    Science.gov (United States)

    Whelan, B. E.; Brunton, M.; Nosenzo, Giorgio; Kay, Daryl; Buys, Henk

    2012-02-01

    This paper describes the application of Fibre Bragg Grating (FBG) based sensors for monitoring road pavement strains caused by mining induced ground subsidence as a result of underground longwall coal mining beneath a major highway in New South Wales, Australia. After a lengthy planning period, the risks to the highway pavement were successfully managed by the highway authority and the mining company through a technical committee. The technical committee comprised representatives of the mining company, the highway authority and specialists in the fields of pavement engineering, geotechnical engineering and subsidence. An important component of the management strategy is the installation of a total of 840 strain and temperature sensors in the highway pavement using FBG arrays encapsulated in glass-fibre composite cables. The sensors and associated demodulation equipment provide continuous strain measurements along the pavement, enabling on-going monitoring of the effects of mining subsidence on the pavement and timely implementation of planned mitigation and response measures to ensure the safety and serviceability of the highway throughout the mining period.

  2. Continuous monitoring of mining induced strain in a road pavement using fiber Bragg grating sensors

    Science.gov (United States)

    Nosenzo, Giorgio; Whelan, B. E.; Brunton, M.; Kay, Daryl; Buys, Henk

    2013-06-01

    This paper describes the application of fiber Bragg grating (FBG) based sensors for monitoring road pavement strains caused by mining induced ground subsidence as a result of underground longwall coal mining beneath a major highway in New South Wales, Australia. After a lengthy planning period, the risks to the highway pavement were successfully managed by the highway authority and the mining company through a technical committee. The technical committee comprised representatives of the mining company, the highway authority and specialists in the fields of pavement engineering, geotechnical engineering and subsidence. An important component of the management strategy is the installation of a total of 840 strain and temperature sensors in the highway pavement using FBG arrays encapsulated in glass-fiber composite cables. The sensors and associated demodulation equipment provide continuous strain measurements along the pavement, enabling on-going monitoring of the effects of mining subsidence on the pavement and timely implementation of planned mitigation and response measures to ensure the safety and serviceability of the highway throughout the mining period.

  3. Variability of particle size-specific fractions of personal coal mine dust exposures.

    Science.gov (United States)

    Seixas, N S; Hewett, P; Robins, T G; Haney, R

    1995-03-01

    This study estimated the ratio of the tracheo-bronchial dust fraction to the fraction collected by a respirable dust sampler for a variety of job classifications found in conventional, continuous, and longwall coal mining sections. The ratios could then be applied in epidemiologic studies to existing respirable dust measurements to estimate thoracic mass concentrations for evaluation of the relative importance of the respirable and thoracic dust fractions to obstructive lung disease. Data collected include particle size distributions from four U.S. underground coal mines using eight-stage personal cascade impactors. A total of 180 samples were examined by mine, occupation and occupations grouped by proximity to the mine face, and by mining technology. Several fractions--that collected by the 10-mm nylon cyclone, the American Conference of Governmental Industrial Hygienists respirable and thoracic particulate mass fractions, and the estimated alveolar and tracheo-bronchial deposition fractions--were estimated. These were not significantly different when grouped by occupation, by proximity of work to the mine face, or by the type of mining technology in use. Distributions from one mine varied from the others, perhaps because it used diesel equipment in the haulage ways, which contributed to the fine aerosol fractions. Results suggest that although the tracheo-bronchial dust fraction may contribute to the development of obstructive lung disease, occupation-specific tracheo-bronchial dust fractions are not likely to produce stronger exposure-response estimates than the historically collected respirable dust concentrations.

  4. Occupational safety and health implications of increased coal utilization.

    Science.gov (United States)

    Bridbord, K; Costello, J; Gamble, J; Groce, D; Hutchison, M; Jones, W; Merchant, J; Ortmeyer, C; Reger, R; Wagner, W L

    1979-12-01

    An area of major concern in considering increased coal production and utilization is the health and safety of increased numbers of workers who mine, process, or utilize coal. Hazards related to mining activities in the past have been especially serious, resulting in many mine related accidental deaths, disabling injuries, and disability and death from chronic lung disease. Underground coal mines are clearly less safe than surface mines. Over one-third of currently employed underground miners experience chronic lung disease. Other stresses include noise and extremes of heat and cold. Newly emphasized technologies of the use of diesel powered mining equipment and the use of longwall mining techniques may be associated with serious health effects. Workers at coal-fired power plants are also potentially at risk of occupational diseases. Occupational safety and health aspects of coal mining are understood well enough today to justify implementing necessary and technically feasible and available control measures to minimize potential problems associated with increased coal production and use in the future. Increased emphasis on safety and health training for inexperienced coal miners expected to enter the work force is clearly needed. The recently enacted Federal Mine Safety and Health Act of 1977 will provide impetus for increased control over hazards in coal mining.

  5. COALVAL

    International Nuclear Information System (INIS)

    Plis, M.N.; Rohrbacher, T.J.; Teeters, D.D.

    1992-01-01

    This paper highlights COALVAL, a coal property evaluation software package developed by the U.S. Bureau of Mines (USBM) on Lotus 1-2-3, version 2.2, spreadsheet. The software is also compatible with version 3.1, and provisionally with version 2.01. COALVAL is a menu-driven program that produces a prefeasibility-level cost analysis of mine-planned coal resources. The software contains cost models for each of five coal mining methods commonly employed in Appalachia: auger, contour strip, mountain top removal, continuous miner and longwall. COALVAL allows individuals to input resource data and the various production, operating, and cost variables that pertain to their property The program can evaluate up to 25 seams, each to be mined with up to 5 different mining methods, within a given area. Summary spreadsheet listing the cost per clean ton to mine the resources, F.O.B. The tipple, are produced for each property, seam, and mining method/seam combination

  6. Report on the FY 1995 basic survey for industrialization related to the survey of overseas geological structure (Pondok Labu East area, Indonesia); 1995 nendo kaigai chishitsu kozo nado chosa ni kakawaru kigyoka kiso chosa (Indonesia Pondok Labu higashi chiku) hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    The survey was conducted based on 'Scope of work for detailed coal exploration in the Pondok Labu East area of East Kalimantan Province, Kalimantan, Indonesia' concluded on June 16, 1995 between NEDO and P.T. Tanito Harum which owns the mining right. The area for survey is approximately 10km west of Tenggarong city, the capital of Kabupaten Kutai, East Kalimantan Province which is northeast part of Kalimantan island of Indonesia. The field survey was divided into the geological/boring survey and the survey of conditions for underground mining development and the infrastructure. This survey made it clear that in the underground mining of PDL7A seam, assuming the minable coal reserve to be 6.81 million tons, it is possible to produce raw coal of 0.5 million tons/year by adopting the longwall pick mining. The raw coal is all prepared, and the yield is 80%. Accordingly, the production of product coal is 0.4 million tons/year. Attached were the boring log (JN9-94-0855), physical log (JN9940856), and BIP survey report (JN9940857). (NEDO)

  7. Experimental Research on Internal Behaviors of Caved Rocks under the Uniaxial Confined Compression

    Directory of Open Access Journals (Sweden)

    Yu-jiang Zhang

    2017-01-01

    Full Text Available As main composition of longwall gob, caved rocks’ behaviors and their impacts under compression crucially influence strata control, subsidence, associated resources extraction, and many other aspects. However, current researches are based on a whole sample, due to looseness of caved rocks and limitation of observation technology. In this paper, an experiment system was built to investigate internal behaviors of caved rocks’ sample, under the uniaxial confined compression, including movement and breakage behavior by the digital image processing technologies. The results show that the compression process of caved rocks could be divided into two stages by relative density. Boundary effect and changes of voids and contact pressure among caved rocks lead to different movement law in different position in sample’s interior. A stratification phenomenon of breakage was discovered, which presents breakage concentration in the middle of the sample. The nonlinear movement and shear dislocation induced by shifts among caved rocks are the reason of the breakage stratification phenomenon. This phenomenon would have an effect on the permeability and seepage research of similar medium.

  8. An Innovative Support Structure for Gob-Side Entry Retention in Steep Coal Seam Mining

    Directory of Open Access Journals (Sweden)

    Jianguo Ning

    2017-05-01

    Full Text Available This study considered longwall working face No. 41101—located in a steeply inclined coal seam at the Awuzisu coal mine in Xinjiang, China—as an example in which macroscopic shear cracks had occurred in the cement-based filling body of the gob-side entry retention structure. A mechanical model of the support structure for the gob-side entry retention was first established. Then, field observations and laboratory tests were used to obtain the force exerted by the coal wall on the main roof, the relationship between the axial bearing capacity and compression ratio of the rubble inside the gob, the supporting force exerted by the rubble and filling body, and the thrust of the rubble on the filling body. The shear stress experienced by the roadside filling body of the gob-side entry retention in working face No. 41101 was calculated to be 15.89 MPa. To meet the needs of roadside support, an innovative roadside backfill–truss support structure was adopted, with a 60° angle of inclination used for the anchor bolts of the gob-side entry retention structure. In this way, the ultimate shear strength was improved by 107.54% in comparison with the cement-based filling body.

  9. Shearer-mounted dust collection: evaluation of ventilated cutting drums. Open File Report (Final)

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, J.S.; Muldoon, T.L.

    1987-06-01

    Effective control of respirable dust is one of the most serious problems associated with longwall mining in the United States. This report describes the development and the underground evaluation of ventilated cutting drums, on a double ended ranging-drum shearer. The ventilated drum uses high pressure (1500 psi) water sprays to draw air (3500 cfm) through 12 airmoving tubes mounted in the drum hub. The sprays draw dusty air from the face side of the drum, scrub the air, and discharge the clean air on the gob side of the drum against a deflector plate. During a three-week underground evaluation, the cutting drums reduced shearer-generated dust levels at the shearer operators position by 40%, at the shield operators downwind of the shearer by 55%, and at the tailgate by 55%. Cutting and loading performance of the drums were superior to the mine's conventional drums. After the evaluation, the mine continued to use the ventilated drums to finish mining the panel.

  10. Estimating the hypothetical dual health impact and cost-effectiveness of the Woman's Condom in selected sub-Saharan African countries.

    Science.gov (United States)

    Mvundura, Mercy; Nundy, Neeti; Kilbourne-Brook, Maggie; Coffey, Patricia S

    2015-01-01

    Female condoms are the only currently available woman-initiated option that offers dual protection from pregnancy and sexually transmitted infections, including HIV. The Woman's Condom is a new female condom designed to provide dual protection and to be highly pleasurable and acceptable. We sought to estimate the potential dual health impact and cost-effectiveness of a Woman's Condom distribution program in 13 sub-Saharan African countries with HIV prevalence rates >4% among adults aged 15-49 years. We used two separate, publicly available models for this analysis, the Impact 2 model developed by Marie Stopes International and the Population Services International disability-adjusted life years (DALY) calculator program. We estimated the potential numbers of pregnancies and DALYs averted when the Woman's Condom is used as a family planning method and the HIV infections and DALYs averted when it is used as an HIV prevention method. Programming 100,000 Woman's Condoms in each of 13 countries in sub-Saharan Africa during a 1-year period could potentially prevent 194 pregnancies and an average of 21 HIV infections in each country. When using the World Health Organization CHOosing Interventions that are Cost-Effective (WHO-CHOICE) criteria as a threshold to infer the potential cost-effectiveness of the Woman's Condom, we found that the Woman's Condom would be considered cost-effective. This was a first and successful attempt to estimate the impact of dual protection of female condoms. The health impact is greater for the use of the Woman's Condom as an HIV prevention method than for contraception. Dual use of the Woman's Condom increases the overall health impact. The Woman's Condom was found to be very cost-effective in all 13 countries in our sample.

  11. THE STRATEGY OF INCREASING THE COMPETITIVENESS OF ROMANIAN AUTOMOBILE INDUSTRY BY TRANSITION TO ALTERNATIVE ENERGY IN INTERNATIONALIZATION CONDITIONS

    Directory of Open Access Journals (Sweden)

    ALINA HAGIU,

    2014-10-01

    Full Text Available The increasing complexity and the increase of the variability grade of the business environment in general, and of the international business environment especially, represented determinant elements of the awareness of strategic issues of international competitiveness of firms and of the intensifying efforts to resolve the many different aspects of it. This paper is addressed to all those interested in the interesting and important issue of competitiveness in general and of the automotive industry competitiveness in particular. We stopped to the car industry as the automotive industry in Romania is one of the industries that have a high added value and a significant share of GDP. A role no less important had the fact that in the case of the automotive industry there are clear opportunities to improve competitiveness in the international market by focusing not only on low cost segments but also pointing to other market segments. The economic crisis has made Dacia sales to exports increase considerably, but the data show that with alleviate of the economic crisis the success of Dacia will begin to decrease. So it turns out that Dacia is a crisis car, and as the crisis will end, the manufacturer must rethink its strategy if it wants to maintain or increase sales. In the present paper we stoped to the transition to alternative energy sources strategy in the functioning of automobiles as a possible way to increase the competitiveness of Romanian automotive industry because all indicates are that alternative sources are the future and we should adapt trends better sooner rather than later.

  12. THE STRATEGY OF INCREASING THE COMPETITIVENESS OF ROMANIAN AUTOMOBILE INDUSTRY BY TRANSITION TO ALTERNATIVE ENERGY IN INTERNATIONALIZATION CONDITIONS

    Directory of Open Access Journals (Sweden)

    ALINA HAGIU

    2014-10-01

    Full Text Available The increasing complexity and the increase of the variability grade of the business environment in general, and of the international business environment especially, represented determinant elements of the awareness of strategic issues of international competitiveness of firms and of the intensifying efforts to resolve the many different aspects of it. This paper is addressed to all those interested in the interesting and important issue of competitiveness in general and of the automotive industry competitiveness in particular. We stopped to the car industry as the automotive industry in Romania is one of the industries that have a high added value and a significant share of GDP. A role no less important had the fact that in the case of the automotive industry there are clear opportunities to improve competitiveness in the international market by focusing not only on low cost segments but also pointing to other market segments. The economic crisis has made Dacia sales to exports increase considerably, but the data show that with alleviate of the economic crisis the success of Dacia will begin to decrease. So it turns out that Dacia is a crisis car, and as the crisis will end, the manufacturer must rethink its strategy if it wants to maintain or increase sales. In the present paper we stoped to the transition to alternative energy sources strategy in the functioning of automobiles as a possible way to increase the competitiveness of Romanian automotive industry because all indicates are that alternative sources are the future and we should adapt trends better sooner rather than later

  13. Impact of Social Franchising on Contraceptive Use When Complemented by Vouchers: A Quasi-Experimental Study in Rural Pakistan

    Science.gov (United States)

    Khurram Azmat, Syed; Tasneem Shaikh, Babar; Hameed, Waqas; Mustafa, Ghulam; Hussain, Wajahat; Asghar, Jamshaid; Ishaque, Muhammad; Ahmed, Aftab; Bilgrami, Mohsina

    2013-01-01

    Background Pakistan has had a low contraceptive prevalence rate for the last two decades; with preference for natural birth spacing methods and condoms. Family planning services offered by the public sector have never fulfilled the demand for contraception, particularly in rural areas. In the private sector, cost is a major constraint. In 2008, Marie Stopes Society – a local NGO started a social franchise programme along with a free voucher scheme to promote uptake of IUCDs amongst the poor. This paper evaluates the effectiveness of this approach, which is designed to increase modern long term contraceptive awareness and use in rural areas of Pakistan. Methodology We used a quasi-experimental study design with controls, selecting one intervention district and one control district from the Sindh and Punjab provinces. In each district, we chose a total of four service providers. A baseline survey was carried out among 4,992 married women of reproductive age (MWRA) in February 2009. Eighteen months after the start of intervention, an independent endline survey was conducted among 4,003 women. We used multilevel logistic regression for analysis using Stata 11. Results Social franchising used alongside free vouchers for long term contraceptive choices significantly increased the awareness of modern contraception. Awareness increased by 5% in the intervention district. Similarly, the ever use of modern contraceptive increased by 28.5%, and the overall contraceptive prevalence rate increased by 19.6%. A significant change (11.1%) was recorded in the uptake of IUCDs, which were being promoted with vouchers. Conclusion Family planning franchise model promotes awareness and uptake of contraceptives. Moreover, supplemented with vouchers, it may enhance the use of IUCDs, which have a significant cost attached. Our research also supports a multi-pronged approach- generating demand through counselling, overcoming financial constraints by offering vouchers, training

  14. Gamma ray fluorescence for in situ evaluation of ore in Witwatersrand gold mines

    International Nuclear Information System (INIS)

    Rolle, R.

    1979-01-01

    A system for quantitative in situ evaluation of ore in Witwatersrand gold mines was researched and subsequently developed. The principle of measurement is based on the excitation of gold K X-rays in rock face samples by the 88 keV gamma radiation from a Cadmium-109 radioisotope source. The X-rays and scattered radiation from the rock matrix are detected by a hyperpure germanium detector cooled by liquid nitrogen in a portable probe. In the fluorescence spectrum the intensity ratio of the gold Kβ peaks to their immediate scattered background is evaluated and quantitatively converted in the portable analyser to area concentration units. All aspects of the physical and instrumental measurement had to be investigated to arrive at a system capable of quantitative evaluation of trace concentrations in stope face ore samples. The parameters of spectrum evaluation were investigated from fundamental principles to allow quantitative assessment of different methods of peak evaluation for optimization of the method as a whole. The basic concepts of random signal processing times were developed together with new concepts of pileup parameters to allow a quantitative description of the data acquisition rate of a complete analog pulse processing system. With this foundation a practical measuring geometry and optimum values for signal processing time parameters, for detector size and for discriminator positions for spectrum evaluation could be determined. Parallel with the derivation of optimum measurement parameters went the development of instruments, their field testing and appraisal of the method. The development of the gamma ray fluorescence method has shown the potential of the method to serve as an ore valuation tool and to assist in the geological identification of strata in Witwatersrand gold mines

  15. Rates of IUCD discontinuation and its associated factors among the clients of a social franchising network in Pakistan

    Science.gov (United States)

    2012-01-01

    Background Modern Intrauterine contraceptive device (IUCD) is very safe, highly effective reversible and inexpensive family planning method which offers 5-10 years of protection against pregnancy. The contraceptive use in Pakistan has been merely 30% for over a decade with IUCD being the least used method. Higher discontinuation rates are documented in developing countries; however no such data is available for Pakistan. Marie Stopes Society (MSS) established a social franchise outlets network branded as 'SURAJ' (Sun) in Pakistan to provide quality family planning services. This study attempts to determine IUCD discontinuation rates and its associated risk factors. Using a semi-structured questionnaire, a cross-sectional study was conducted with 3000 clients who availed IUCD services from Suraj provider 6, 12 and 24 month back,. Data were analyzed in SPSS 17.0; adjusted prevalence ratios were calculated to see associations between discontinuation and its risk factors. Case presentation We found that 22.7% of the IUCD acceptors experienced some health problem; while the overall discontinuation rate was 18.9% with average time of usage of 7.4 (SD ± 5.8) months before discontinuation. Half of them showed health concerns (49.8%); of which a majority (70.2%) returned to Suraj provider for IUCD removal. Women living in Punjab, residing at a travelling time of 30-60 minutes and no previous use of contraceptive are more likely to discontinue IUCD. However, among total women 81.7% still expressed willingness to avail IUCD services from Suraj provider in future, if needed. Conclusion The findings suggest a need for training the providers and field workers to prevent early discontinuation of IUCD among the Suraj clients and by addressing the health concerns through proper counseling, continued follow-up and immediate medical aid/referral in case of complications. PMID:22458444

  16. Impact of social franchising on contraceptive use when complemented by vouchers: a quasi-experimental study in rural Pakistan.

    Directory of Open Access Journals (Sweden)

    Syed Khurram Azmat

    Full Text Available Pakistan has had a low contraceptive prevalence rate for the last two decades; with preference for natural birth spacing methods and condoms. Family planning services offered by the public sector have never fulfilled the demand for contraception, particularly in rural areas. In the private sector, cost is a major constraint. In 2008, Marie Stopes Society - a local NGO started a social franchise programme along with a free voucher scheme to promote uptake of IUCDs amongst the poor. This paper evaluates the effectiveness of this approach, which is designed to increase modern long term contraceptive awareness and use in rural areas of Pakistan.We used a quasi-experimental study design with controls, selecting one intervention district and one control district from the Sindh and Punjab provinces. In each district, we chose a total of four service providers. A baseline survey was carried out among 4,992 married women of reproductive age (MWRA in February 2009. Eighteen months after the start of intervention, an independent endline survey was conducted among 4,003 women. We used multilevel logistic regression for analysis using Stata 11.Social franchising used alongside free vouchers for long term contraceptive choices significantly increased the awareness of modern contraception. Awareness increased by 5% in the intervention district. Similarly, the ever use of modern contraceptive increased by 28.5%, and the overall contraceptive prevalence rate increased by 19.6%. A significant change (11.1% was recorded in the uptake of IUCDs, which were being promoted with vouchers.Family planning franchise model promotes awareness and uptake of contraceptives. Moreover, supplemented with vouchers, it may enhance the use of IUCDs, which have a significant cost attached. Our research also supports a multi-pronged approach- generating demand through counselling, overcoming financial constraints by offering vouchers, training, accreditation and branding of the

  17. Impact of social franchising on contraceptive use when complemented by vouchers: a quasi-experimental study in rural Pakistan.

    Science.gov (United States)

    Azmat, Syed Khurram; Khurram Azmat, Syed; Shaikh, Babar Tasneem; Tasneem Shaikh, Babar; Hameed, Waqas; Mustafa, Ghulam; Hussain, Wajahat; Asghar, Jamshaid; Ishaque, Muhammad; Ahmed, Aftab; Bilgrami, Mohsina

    2013-01-01

    Pakistan has had a low contraceptive prevalence rate for the last two decades; with preference for natural birth spacing methods and condoms. Family planning services offered by the public sector have never fulfilled the demand for contraception, particularly in rural areas. In the private sector, cost is a major constraint. In 2008, Marie Stopes Society - a local NGO started a social franchise programme along with a free voucher scheme to promote uptake of IUCDs amongst the poor. This paper evaluates the effectiveness of this approach, which is designed to increase modern long term contraceptive awareness and use in rural areas of Pakistan. We used a quasi-experimental study design with controls, selecting one intervention district and one control district from the Sindh and Punjab provinces. In each district, we chose a total of four service providers. A baseline survey was carried out among 4,992 married women of reproductive age (MWRA) in February 2009. Eighteen months after the start of intervention, an independent endline survey was conducted among 4,003 women. We used multilevel logistic regression for analysis using Stata 11. Social franchising used alongside free vouchers for long term contraceptive choices significantly increased the awareness of modern contraception. Awareness increased by 5% in the intervention district. Similarly, the ever use of modern contraceptive increased by 28.5%, and the overall contraceptive prevalence rate increased by 19.6%. A significant change (11.1%) was recorded in the uptake of IUCDs, which were being promoted with vouchers. Family planning franchise model promotes awareness and uptake of contraceptives. Moreover, supplemented with vouchers, it may enhance the use of IUCDs, which have a significant cost attached. Our research also supports a multi-pronged approach- generating demand through counselling, overcoming financial constraints by offering vouchers, training, accreditation and branding of the service providers

  18. Ventilation of uranium mines

    International Nuclear Information System (INIS)

    Francois, Y.; Pradel, J.; Zettwoog, P.; Dumas, M.

    1975-01-01

    In the first part of the paper the authors describe the ventilation of French mines in terms of the primary ventilation system, which brings the outside air close to the working places using the overall structure of the mine to form the airways, and the secondary ventilation system, which is for the distribution of the primary air or for the ventilation of the development drifts and blind tunnels. Brief mention is made of the French regulations on the ventilation of mines in general and uranium mines in particular. The authors describe the equipment used and discuss the installed capacities and air flow per man and per working place. The difficulties encountered in properly ventilating various types of working places are mentioned, such as sublevel development drifts, reinforced stopes, and storage chambers with an artificial crown. The second part of the paper is devoted to computer calculations of the primary ventilation system. It is explained why the Commissariat a l'energie atomique has found it necessary to make these calculations. Without restating the mathematical theories underlying the methods employed, the authors demonstrate how simple measuring instruments and a small-size computer can be used to solve the ventilation problems arising in French mines. Emphasis is given to the layout of the ventilation system and to air flow and negative pressure measurements at the base of the mine. The authors show how calculations can be applied to new heading operations, a change in resistance, the replacement or addition of a ventilator, and a new air inlet or outlet. The authors come to the conclusion that since ventilation is at present the most reliable way of avoiding the pollution of mines, a thorough knowledge of the capabilities in this respect can often help improve working conditions. Despite the progress made, however, constant surveillance of the ventilation systems in uranium mines by a separate team with no responsibility for production problems is

  19. Effect of a mobile phone-based intervention on post-abortion contraception: a randomized controlled trial in Cambodia

    Science.gov (United States)

    Ngo, Thoai D; Gold, Judy; Edwards, Phil; Vannak, Uk; Sokhey, Ly; Machiyama, Kazuyo; Slaymaker, Emma; Warnock, Ruby; McCarthy, Ona; Free, Caroline

    2015-01-01

    Abstract Objective To assess the effect of a mobile phone-based intervention (mHealth) on post-abortion contraception use by women in Cambodia. Methods The Mobile Technology for Improved Family Planning (MOTIF) study involved women who sought safe abortion services at four Marie Stopes International clinics in Cambodia. We randomly allocated 249 women to a mobile phone-based intervention, which comprised six automated, interactive voice messages with counsellor phone support, as required, whereas 251 women were allocated to a control group receiving standard care. The primary outcome was the self-reported use of an effective contraceptive method, 4 and 12 months after an abortion. Findings Data on effective contraceptive use were available for 431 (86%) participants at 4 months and 328 (66%) at 12 months. Significantly more women in the intervention than the control group reported effective contraception use at 4 months (64% versus 46%, respectively; relative risk, RR: 1.39; 95% confidence interval, CI: 1.17–1.66) but not at 12 months (50% versus 43%, respectively; RR: 1.16; 95% CI: 0.92–1.47). However, significantly more women in the intervention group reported using a long-acting contraceptive method at both follow-up times. There was no significant difference between the groups in repeat pregnancies or abortions at 4 or 12 months. Conclusion Adding a mobile phone-based intervention to abortion care services in Cambodia had a short-term effect on the overall use of any effective contraception, while the use of long-acting contraceptive methods lasted throughout the study period. PMID:26668436

  20. Nigeria using more condoms.

    Science.gov (United States)

    1997-09-01

    Marie Stopes International says a project it supports in Nigeria is making good progress in its efforts to promote the use of condoms to protect against STDs and for contraception. The program, which uses social marketing methods, is headed by Stewart Parkinson from the UK. His previous experience has been in the private sector; he has worked in sales, marketing, and advertising for companies like Coca Cola, Budweiser, Securicor, and Mates. "Social marketing," he says, "is simply getting people to buy a product". He sees no clash with more conventional health education practitioners, believing that the two approaches can complement each other. "Much of the work simply involves pointing out the benefits of condoms," says Parkinson. "You can convert large numbers of people to the idea in a short space of time if you get the message right]" Nevertheless, as he points out, the conversion rate usually drops after that. "At first the take-up is from middle-income people, who already have a latent demand for condoms. The poor are harder to reach." He says Nigeria is a very suitable country for a private sector approach to condom promotion, as there is no functioning public sector. He recently paid a visit to Zimbabwe, where the public sector is strong, and agrees that different approaches may be suitable there. The scheme provided 85% of the 65 million condoms used in Nigeria last year. Stewart Parkinson says, "It's working out at only US$5 to provide protection for one couple per year--a very cheap intervention]" full text

  1. Public sphere of politics: between classical grounds and new political actuality

    Directory of Open Access Journals (Sweden)

    O. A. Tretyak

    2016-10-01

    Full Text Available The public sphere of politics as a theoretical concept of modern political science has been discussed in the article. The reasons of the increasing interest to the public sphere is a dominating subject. Studied The phenomenon of the public sphere being a tool of theoretical and methodological definition of the political world’s boundaries has been studied. The value aspects of media activity in the contemporary politics has been investigated. An attempt has been made to establish the potential of political publicity for the qualitative understanding of participatory democracy. The potential of the public sphere in the development of civil society and social capital has been described. The distinction between the public sphere of politics and political communication in the specific conditions of modern transformational societies has been reasonably grounded. The importance of the presence of state power in all spheres of life of the transformational society has been stressed. Such transformation has not been stoped after the liberal market reforms, which had to ensure the existence of a formal representative democracy. The influence of the elite and expert groups being the reason of the absence of really functioning future civil society has been considered. The features of the formation of civil and social activities as a precondition for the democratic political class’ functioning have been studied. The specifics of public political activity being the prerogative of the competent entities’ political broadcasting have been analyzed. The gradual formation of cyber public sphere and its political branch segment has been revealed. Thorough attention has been given to the processes of the public sphere’s politicization which are usual for primarily authoritarian and closed societies.

  2. Differential diagnosis of recurrent bronchitis in children

    Directory of Open Access Journals (Sweden)

    I. I. Zakirov

    2016-01-01

    Full Text Available The interest of the doctors — pediatricians to recurrent bronchitis is caused by its high specific weight in the structure of bronchopulmonary pathology in children, the complexity and the need to search the differential selection of an individual regimen and prevention. Recurrent bronchitis with bronchoobstructive syndromes patient is regarded as a predictor of asthma, however, erroneously consider these nosological forms as the stages of a single pathophysiological chain as congenital and acquired diseases of respiratory system, pathology of gastro-intestinal tract, cardio-vascular system can masquerade as recurrent bronchitis. The aim of this work — to analyze the current medical literature on the problem of differential search causes leading recurrent respiratory syndrome in children. Materials and methods. The review publications domestic and foreign authors studied data from clinical and epidemiological studies. Results and its discussion. Anatomical physiological characteristics of the respiratory tract, complicated premorbid background, the re-infection of the child respiratory infection contribute to the recurrent course of bronchitis. The most common recurrent bronchitis is transient, recurrent bronchitis episodes completely stoped with the age of the child. Recurrent respiratory infections can fix bronchial hyperreactivity and with the presence of aggravated allergic history lead to the development of asthma. Severe bronchitis, resistance to standard scheme of therapy, the frequent recurrence of respiratory syndrome dictate the need to expand the diagnostic research to clarify the leading cause of recurrent bronchitis. Conclusion. Recurrent bronchitis is considered as a separate nosological form. At the same time, by repeated episodes of respiratory infection may be masked by malformations, hereditary diseases of respiratory system, bronchus foreign body microaspiration syndrome, pathology of the cardio-vascular system. 

  3. Evaluating a LARC Expansion Program in 14 Sub-Saharan African Countries: A Service Delivery Model for Meeting FP2020 Goals.

    Science.gov (United States)

    Ngo, Thoai D; Nuccio, Olivia; Pereira, Shreya K; Footman, Katharine; Reiss, Kate

    2017-09-01

    Objectives In many sub-Saharan African countries, the use of long-acting reversible contraceptives (LARCs) is low while unmet need for family planning (FP) remains high. We evaluated the effectiveness of a LARC access expansion initiative in reaching young, less educated, poor, and rural women. Methods Starting in 2008, Marie Stopes International (MSI) has implemented a cross-country expansion intervention to increase access to LARCs through static clinics, mobile outreach units, and social franchising of private sector providers. We analyzed routine service statistics for 2008-2014 and 2014 client exit interview data. Indicators of effectiveness were the number of LARCs provided and the percentages of LARC clients who had not used a modern contraceptive in the last 3 months ("adopters"); switched from a short-term contraceptive to a LARC ("switchers"); were aged <25; lived in extreme poverty; had not completed primary school; lived in rural areas; and reported satisfaction with their overall experience at the facility/site. Results Our annual LARC service distribution increased 1037 % (from 149,881 to over 1.7 million) over 2008-2014. Of 3816 LARC clients interviewed, 46 % were adopters and 46 % switchers; 37 % were aged 15-24, 42 % had not completed primary education, and 56 % lived in a rural location. Satisfaction with services received was rated 4.46 out of 5. Conclusions The effectiveness of the LARC expansion in these 14 sub-Saharan African FP programs demonstrates vast untapped potential for wider use of LARC methods, and suggests that this service delivery model is a plausible way to support FP 2020 goals of reaching those with an unmet need for FP.

  4. Mineral Mapping with Imaging Spectroscopy: The Ray Mine, AZ

    Science.gov (United States)

    Clark, Roger N.; Vance, J. Sam; Livo, K. Eric; Green, Robert O.

    1998-01-01

    Mineral maps generated for the Ray Mine, Arizona were analyzed to determine if imaging spectroscopy can provide accurate information for environmental management of active and abandoned mine regions. The Ray Mine, owned by the ASARCO Corporation, covers an area of 5700 acres and is situated in Pinal County, Arizona about 70 miles north of Tucson near Hayden, Arizona. This open-pit mine has been a major source of copper since 1911, producing an estimated 4.5 million tons of copper since its inception. Until 1955 mining was accomplished by underground block caving and shrinkage stope methods. (excavation by working in stepped series usually employed in a vertical or steeply inclined orebody) In 1955, the mine was completely converted to open pit method mining with the bulk of the production from sulfide ore using recovery by concentrating and smelting. Beginning in 1969 a significant production contribution has been from the leaching and solvent extraction-electrowinnowing method of silicate and oxide ores. Published reserves in the deposit as of 1992 are 1.1 billion tons at 0.6 percent copper. The Environmental Protection Agency, in conjunction with ASARCO, and NASA/JPL obtained AVIRIS data over the mine in 1997 as part of the EPA Advanced Measurement Initiative (AMI) (Tom Mace, Principal Investigator). This AVIRIS data set is being used to compare and contrast the accuracy and environmental monitoring capabilities of remote sensing technologies: visible-near-IR imaging spectroscopy, multispectral visible and, near-IR sensors, thermal instruments, and radar platforms. The goal of this effort is to determine if these various technologies provide useful information for envirorunental management of active and abandoned mine sites in the arid western United States. This paper focuses on the analysis of AVIRIS data for assessing the impact of the Ray Mine on Mineral Creek. Mineral Creek flows to the Gila River. This paper discusses our preliminary AVIRIS mineral mapping

  5. Increasing Contraceptive Access for Hard-to-Reach Populations With Vouchers and Social Franchising in Uganda.

    Science.gov (United States)

    Bellows, Benjamin; Mackay, Anna; Dingle, Antonia; Tuyiragize, Richard; Nnyombi, William; Dasgupta, Aisha

    2017-09-27

    From 2001 to 2011, modern contraceptive prevalence in Uganda increased from 18% to 26%. However, modern method use, in particular use of long-acting reversible contraceptives (LARCs) and permanent methods (PMs), remained low. In the 2011 Uganda Demographic and Health Survey, only 1 of 5 married women used a LARC or PM even though 34% indicated an unmet need for contraception. Between 2011 and 2014, a social franchise and family planning voucher program, supporting 400 private facilities to provide family planning counseling and broaden contraceptive choice by adding LARCs and PMs to the service mix, offered a voucher to enable poor women to access family planning services at franchised facilities. This study analyzes service trends and voucher client demographics and estimates the contribution of the program to increasing contraceptive prevalence in Uganda, using the Impact 2 model developed by Marie Stopes International. Between March 2011 and December 2014, 330,826 women received a family planning service using the voucher, of which 70% of voucher clients chose an implant and 25% chose an intrauterine device. The median age of voucher users was 28 years; 79% had no education or only a primary education; and 48% reported they were unemployed or a housewife. We estimated that by 2014, 280,000 of the approximately 8,600,000 women of reproductive age in Uganda were using a contraceptive method provided by the program and that 120,000 of the clients were "additional users" of contraception, contributing 1.4 percentage points to the national modern contraceptive prevalence rate. The combination of family planning vouchers and a franchise-based quality improvement initiative can leverage existing private health infrastructure to substantially expand family planning access and choice for disadvantaged populations and potentially improve contraceptive prevalence when scaled nationally. © Bellows et al.

  6. Rates of IUCD discontinuation and its associated factors among the clients of a social franchising network in Pakistan.

    Science.gov (United States)

    Azmat, Syed Khurram; Shaikh, Babar Tasneem; Hameed, Waqas; Bilgrami, Mohsina; Mustafa, Ghulam; Ali, Muhammad; Ishaque, Muhammad; Hussain, Wajahat; Ahmed, Aftab

    2012-03-29

    Modern Intrauterine contraceptive device (IUCD) is very safe, highly effective reversible and inexpensive family planning method which offers 5-10 years of protection against pregnancy. The contraceptive use in Pakistan has been merely 30% for over a decade with IUCD being the least used method. Higher discontinuation rates are documented in developing countries; however no such data is available for Pakistan. Marie Stopes Society (MSS) established a social franchise outlets network branded as 'SURAJ' (Sun) in Pakistan to provide quality family planning services. This study attempts to determine IUCD discontinuation rates and its associated risk factors. Using a semi-structured questionnaire, a cross-sectional study was conducted with 3000 clients who availed IUCD services from Suraj provider 6, 12 and 24 month back,. Data were analyzed in SPSS 17.0; adjusted prevalence ratios were calculated to see associations between discontinuation and its risk factors. We found that 22.7% of the IUCD acceptors experienced some health problem; while the overall discontinuation rate was 18.9% with average time of usage of 7.4 (SD ± 5.8) months before discontinuation. Half of them showed health concerns (49.8%); of which a majority (70.2%) returned to Suraj provider for IUCD removal. Women living in Punjab, residing at a travelling time of 30-60 minutes and no previous use of contraceptive are more likely to discontinue IUCD. However, among total women 81.7% still expressed willingness to avail IUCD services from Suraj provider in future, if needed. The findings suggest a need for training the providers and field workers to prevent early discontinuation of IUCD among the Suraj clients and by addressing the health concerns through proper counseling, continued follow-up and immediate medical aid/referral in case of complications.

  7. Rates of IUCD discontinuation and its associated factors among the clients of a social franchising network in Pakistan

    Directory of Open Access Journals (Sweden)

    Azmat Syed

    2012-03-01

    Full Text Available Abstract Background Modern Intrauterine contraceptive device (IUCD is very safe, highly effective reversible and inexpensive family planning method which offers 5-10 years of protection against pregnancy. The contraceptive use in Pakistan has been merely 30% for over a decade with IUCD being the least used method. Higher discontinuation rates are documented in developing countries; however no such data is available for Pakistan. Marie Stopes Society (MSS established a social franchise outlets network branded as 'SURAJ' (Sun in Pakistan to provide quality family planning services. This study attempts to determine IUCD discontinuation rates and its associated risk factors. Using a semi-structured questionnaire, a cross-sectional study was conducted with 3000 clients who availed IUCD services from Suraj provider 6, 12 and 24 month back,. Data were analyzed in SPSS 17.0; adjusted prevalence ratios were calculated to see associations between discontinuation and its risk factors. Case presentation We found that 22.7% of the IUCD acceptors experienced some health problem; while the overall discontinuation rate was 18.9% with average time of usage of 7.4 (SD ± 5.8 months before discontinuation. Half of them showed health concerns (49.8%; of which a majority (70.2% returned to Suraj provider for IUCD removal. Women living in Punjab, residing at a travelling time of 30-60 minutes and no previous use of contraceptive are more likely to discontinue IUCD. However, among total women 81.7% still expressed willingness to avail IUCD services from Suraj provider in future, if needed. Conclusion The findings suggest a need for training the providers and field workers to prevent early discontinuation of IUCD among the Suraj clients and by addressing the health concerns through proper counseling, continued follow-up and immediate medical aid/referral in case of complications.

  8. Factors contributing to industrial accidents during coal mining operations. [Bulgaria: 1978 and 1979

    Energy Technology Data Exchange (ETDEWEB)

    Nedyalkova, N.

    1980-01-01

    Four hundred cases of severe industrial traumas from 1978 to 1979 were analyzed on a computer. The information was coded into four groups, characterizing the human undergoing the trauma, the time of the event, the working environment and the equipment involved, the causes of the accident (objective and subjective with respect to the victim). Eighty-six variables (values) of two types were input into the computer: quantitative (age, length of service at that job and in the profession, the month, date, day, hour and shift); categorical (profession- 11 subgroups; place of the event- 12 subgroups; work being done at the time of the event- 12 subgroups; indirect cause of the accident- 10 subgroups; circumstances of the accident- 11 subgroups; objective 15 subgroups and subjective- 7 subgroups of causes with respect to the victim). Ten factors were identified which lead to industrial accidents (By level of importance); poor dicipline, work shift, profession, date of the month, mine transport, poor instruction, unsafe work place, length of service, month of the year, poor organization of the work place. The following conclusions were made on the basis of these results: 1) poor discipline is undoubtably a primary factor in work safety; In a narrow context, it is connected with insufficient knowledge and lack of expertise, inability to work safely, poor control and organization of the work place; 48% of industrial accidents occur among stope miners and timbermen; 27% among transport workers; 2) 50% of the accidents occurred during the first shift, 16% between 11 and 12 o'clock; 3) 39.5% occurred at the end of the month; 4) 39% occurred due to insufficient and poor quality instruction, lack of necessary expertise and the ability to work safely.

  9. Effect of a mobile phone-based intervention on post-abortion contraception: a randomized controlled trial in Cambodia.

    Science.gov (United States)

    Smith, Chris; Ngo, Thoai D; Gold, Judy; Edwards, Phil; Vannak, Uk; Sokhey, Ly; Machiyama, Kazuyo; Slaymaker, Emma; Warnock, Ruby; McCarthy, Ona; Free, Caroline

    2015-12-01

    To assess the effect of a mobile phone-based intervention (mHealth) on post-abortion contraception use by women in Cambodia. The Mobile Technology for Improved Family Planning (MOTIF) study involved women who sought safe abortion services at four Marie Stopes International clinics in Cambodia. We randomly allocated 249 women to a mobile phone-based intervention, which comprised six automated, interactive voice messages with counsellor phone support, as required, whereas 251 women were allocated to a control group receiving standard care. The primary outcome was the self-reported use of an effective contraceptive method, 4 and 12 months after an abortion. Data on effective contraceptive use were available for 431 (86%) participants at 4 months and 328 (66%) at 12 months. Significantly more women in the intervention than the control group reported effective contraception use at 4 months (64% versus 46%, respectively; relative risk, RR: 1.39; 95% confidence interval, CI: 1.17-1.66) but not at 12 months (50% versus 43%, respectively; RR: 1.16; 95% CI: 0.92-1.47). However, significantly more women in the intervention group reported using a long-acting contraceptive method at both follow-up times. There was no significant difference between the groups in repeat pregnancies or abortions at 4 or 12 months. Adding a mobile phone-based intervention to abortion care services in Cambodia had a short-term effect on the overall use of any effective contraception, while the use of long-acting contraceptive methods lasted throughout the study period.

  10. The forecast of mining-induced seismicity and the consequent risk of damage to the excavation in the area of seismic event

    Directory of Open Access Journals (Sweden)

    Jan Drzewiecki

    2017-01-01

    Full Text Available The Central Mining Institute has developed a method for forecasting the amount of seismic energy created by tremors induced by mining operations. The results of geophysical measurements of S wave velocity anomalies in a rock mass or the results of analytic calculations of the values of pressure on the horizon of the elastic layers are used in the process of calculating the energy. The calculation program which has been developed and adopted has been modified over recent years and it now enables not only the prediction of the energy of dynamic phenomena induced by mining but also the forecasting of the devastating range of seismic shock. The results obtained from this calculation, usually presented in a more readable graphic form, are useful for the macroscopic evaluation of locations that are potential sources of seismic energy. Forecasting of the maximum energy of seismic shock without prior knowledge of the location of the shock's source, does not allow shock attenuation that results from, for example, a distance of tremor source from the excavation which will be affected by seismic energy, to be taken into consideration. The phenomena of energy dissipation, which is taken into account in the forecasts, create a new quality of assessment of threat to the excavation. The paper presents the principle of a method of forecasting the seismic energy of a shock and the risk of damage to the excavation as a result of the impact of its energy wave. The solution assumes that the source of the energy shock is a resilient layer in which the sum of the gravitational stresses, resulting from natural disturbances and those induced by the conducted or planned mining exploitation, is estimated. The proposed solution assumes a spherical model for the tremor source, for which seismic energy is forecasted as a function of the longwall advance and the elementary value of seismic energy destroying the excavation. Subsequently, the following are calculated for the

  11. Coal-mining seismicity and ground-shaking hazard: A case study in the Trail Mountain area, Emery County, Utah

    Science.gov (United States)

    Arabasz, W.J.; Nava, S.J.; McCarter, M.K.; Pankow, K.L.; Pechmann, J.C.; Ake, J.; McGarr, A.

    2005-01-01

    We describe a multipart study to quantify the potential ground-shaking hazard to Joes Valley Dam, a 58-m-high earthfill dam, posed by mining-induced seismicity (MIS) from future underground coal mining, which could approach as close as ???1 km to the dam. To characterize future MIS close to the dam, we studied MIS located ???3-7 km from the dam at the Trail Mountain coal mine. A 12-station local seismic network (11 stations above ground, one below, combining eight triaxial accelerometers and varied velocity sensors) was operated in the Trail Mountain area from late 2000 through mid-2001 for the dual purpose of (1) continuously monitoring and locating MIS associated with longwall mining at a depth of 0.5-0.6 km and (2) recording high-quality data to develop ground-motion prediction equations for the shallow MIS. (Ground-motion attenuation relationships and moment-tensor results are reported in companion articles.) Utilizing a data set of 1913 earthquakes (M ??? 2.2), we describe space-time-magnitude distributions of the observed MIS and source-mechanism information. The MIS was highly correlated with mining activity both in space and time. Most of the better-located events have depths constrained within ??0.6 km of mine level. For the preponderance (98%) of the 1913 located events, only dilatational P-wave first motions were observed, consistent with other evidence for implosive or collapse-type mechanisms associated with coal mining in this region. We assess a probable maximum magnitude of M 3.9 (84th percentile of a cumulative distribution) for potential MIS close to Joes Valley Dam based on both the worldwide and regional record of coal-mining-related MIS and the local geology and future mining scenarios.

  12. A Remote Sensing Approach to Environmental Monitoring in a Reclaimed Mine Area

    Directory of Open Access Journals (Sweden)

    Rajchandar Padmanaban

    2017-12-01

    Full Text Available Mining for resources extraction may lead to geological and associated environmental changes due to ground movements, collision with mining cavities, and deformation of aquifers. Geological changes may continue in a reclaimed mine area, and the deformed aquifers may entail a breakdown of substrates and an increase in ground water tables, which may cause surface area inundation. Consequently, a reclaimed mine area may experience surface area collapse, i.e., subsidence, and degradation of vegetation productivity. Thus, monitoring short-term landscape dynamics in a reclaimed mine area may provide important information on the long-term geological and environmental impacts of mining activities. We studied landscape dynamics in Kirchheller Heide, Germany, which experienced extensive soil movement due to longwall mining without stowing, using Landsat imageries between 2013 and 2016. A Random Forest image classification technique was applied to analyze land-use and landcover dynamics, and the growth of wetland areas was assessed using a Spectral Mixture Analysis (SMA. We also analyzed the changes in vegetation productivity using a Normalized Difference Vegetation Index (NDVI. We observed a 19.9% growth of wetland area within four years, with 87.2% growth in the coverage of two major waterbodies in the reclaimed mine area. NDVI values indicate that the productivity of 66.5% of vegetation of the Kirchheller Heide was degraded due to changes in ground water tables and surface flooding. Our results inform environmental management and mining reclamation authorities about the subsidence spots and priority mitigation areas from land surface and vegetation degradation in Kirchheller Heide.

  13. Gas Permeability Evolution Mechanism and Comprehensive Gas Drainage Technology for Thin Coal Seam Mining

    Directory of Open Access Journals (Sweden)

    Fangtian Wang

    2017-09-01

    Full Text Available A thin coal seam mined as a protective coal seam above a gas outburst coal seam plays a central role in decreasing the degree of stress placed on a protected seam, thus increasing gas permeability levels and desorption capacities to dramatically eliminate gas outburst risk for the protected seam. However, when multiple layers of coal seams are present, stress-relieved gas from adjacent coal seams can cause a gas explosion. Thus, the post-drainage of gas from fractured and de-stressed strata should be applied. Comprehensive studies of gas permeability evolution mechanisms and gas seepage rules of protected seams close to protective seams that occur during protective seam mining must be carried out. Based on the case of the LongWall (LW 23209 working face in the Hancheng coal mine, Shaanxi Province, this paper presents a seepage model developed through the FLAC3D software program (version 5.0, Itasca Consulting Group, Inc., Minneapolis, MI, USA from which gas flow characteristics can be reflected by changes in rock mass permeability. A method involving theoretical analysis and numerical simulation was used to analyze stress relief and gas permeability evolution mechanisms present during broken rock mass compaction in a goaf. This process occurs over a reasonable amount of extraction time and in appropriate locations for comprehensive gas extraction technologies. In using this comprehensive gas drainage technological tool, the safe and efficient co-extraction of thin coal seams and gas resources can be realized, thus creating a favorable environment for the safe mining of coal and gas outburst seams.

  14. A Model of Equilibrium Conditions of Roof Rock Mass Giving Consideration to the Yielding Capacity of Powered Supports

    Science.gov (United States)

    Jaszczuk, Marek; Pawlikowski, Arkadiusz

    2017-12-01

    The work presents the model of interactions between the powered roof support units and the rock mass, while giving consideration to the yielding capacity of the supports - a value used for the analysis of equilibrium conditions of roof rock mass strata in geological and mining conditions of a given longwall. In the model, the roof rock mass is kept in equilibrium by: support units, the seam, goafs, and caving rocks (Fig. 1). In the assumed model of external load on the powered roof support units it is a new development - in relation to the model applied in selection of supports based on the allowable deflection of roof theory - that the load bearing capacity is dependent on the increment of the inclination of the roof rock mass and on the properties of the working medium, while giving consideration to the air pockets in the hydraulic systems, the load of the caving rocks on the caving shield, introducing the RA support value of the roof rock mass by the coal seam as a closed-form expression and while giving consideration to the additional support provided by the rocks of the goaf as a horizontal component R01H of the goaf reaction. To determine the roof maintenance conditions it is necessary to know the characteristics linking the yielding capacity of the support units with the heading convergence, which may be measured as the inclination angle of the roof rock mass. In worldwide mining, Ground Reaction Curves are used, which allow to determine the required yielding capacity of support units based on the relation between the load exerted on the unit and the convergence of the heading ensuring the equilibrium of the roof rock mass. (Figs. 4 and 8). The equilibrium of the roof rock mass in given conditions is determined at the displacement of the rock mass by the α angle, which impacts the following values: yielding capacity of units FN, vertical component of goaf reaction R01V and the horizontal component of goaf reaction R01H. In the model of load on the support

  15. UPAYA PERBAIKAN KUALITAS KERUPUK UDANG TIPE MILD-B PADA PT. INDOSIGMA SURYA CORPORATION

    Directory of Open Access Journals (Sweden)

    Naniek Utami Handayani

    2012-02-01

    Full Text Available Perusahaan makanan adalah satu bisnis yang menghasilkan makanan untuk manusia. Salah satu bentuk makanan adalah kerupuk udang. Perusahaan makanan berkembang luas di Indonesia. Banyak perusahaan di dalam dan juga luar negeri aktif dalam hal ini. Konmpetisi membuat setiap perusahaan mencari cara untuk mampu berdiri. Tak terkecuali PT. INDOSIGMA SURYA CORP. Salah satu usaha PT. INDOSIGMA SURYA CORP untuk mampu bertahan sebagai satu industri makanan di Indonesia adalah tidak berhenti meningkatkan kualitas produk yang mana mereka hasilkan. Tetapi dalam proses produksi masih ditemukan produk cacat dan rework dalam jumlah tinggi. Sebagian besar produk rework terjadi pada jenis Mild B dari kerupuk udang karena Moisture Content level (MC tidak sesuai standar. Laporan ini bertujuan untuk mencari dan meneliti penyebab Moisture Content level (MC tidak sesuai dari standar sehingga didapatkan solusi untuk menyelesaikan masalah. Metoda yang digunakan dalam laporan ini adalah Sig Sigma dengan proses tahap adalah DMAIC (Define-Measure-Analyze-Improve-Control. Dari penerapan metoda dihasilkan perbaikan untuk PT. INDOSIGMA SURYA CORP untuk mengurangi sejumlah produk rework. Kata kunci : Sig Sigma, MC (Moisture Content, Kerupuk udang               Food Manufacturing is a business that produce food for human. One of forming food that is prawn crisply. Food manufacturing expand in Indonesia. A lot of good company own in and also abroad active in this. Tighten emulation make every company look for the way of in order to still able to stand up. Do not aside from PT. INDOSIGMA SURYA CORP. One of effort of PT. INDOSIGMA SURYA CORP in order to able to hold out as one of food industry in Indonesia is non-stoped to improve the quality of product which they yield. But from the production process remain to be found defect product and high rework. Mostly rework happened in type Mild B of  prawn crisply because Moisture Content level (MC inappropriate from the

  16. Stress monitoring versus microseismic ruptures in an active deep mine

    Science.gov (United States)

    Tonnellier, Alice; Bouffier, Christian; Bigarré, Pascal; Nyström, Anders; Österberg, Anders; Fjellström, Peter

    2015-04-01

    Nowadays, underground mining industry has developed high-technology mass mining methods to optimise the productivity at deep levels. Such massive extraction induces high-level stress redistribution generating seismic events around the mining works, threatening safety and economics. For this reason mining irregular deep ore bodies calls for steadily enhanced scientific practises and technologies to guarantee the mine environment to be safer and stable for the miners and the infrastructures. INERIS, within the framework of the FP7 European project I2Mine and in partnership with the Swedish mining company Boliden, has developed new methodologies in order to monitor both quasi-static stress changes and ruptures in a seismic prone area. To this purpose, a unique local permanent microseismic and stress monitoring network has been installed into the deep-working Garpenberg mine situated to the north of Uppsala (Sweden). In this mine, ore is extracted using sublevel stoping with paste fill production/distribution system and long-hole drilling method. This monitoring network has been deployed between about 1100 and 1250 meter depth. It consists in six 1-component and five 3-component microseismic probes (14-Hz geophones) deployed in the Lappberget area, in addition to three 3D stress monitoring cells that focus on a very local exploited area. Objective is three-fold: to quantify accurately quasi-static stress changes and freshly-induced stress gradients with drift development in the orebody, to study quantitatively those stress changes versus induced detected and located microseismic ruptures, and possibly to identify quasi-static stress transfer from those seismic ruptures. Geophysical and geotechnical data are acquired continuously and automatically transferred to INERIS datacenter through the web. They are made available on a secured web cloud monitoring infrastructure called e.cenaris and completed with mine data. Such interface enables the visualisation of the

  17. Relações entre uso do solo, relevo e fertilidade do solo em escala de microbacia Relationships among land use, relief and soil fertility at watershed scale

    Directory of Open Access Journals (Sweden)

    Antonio C. dos Santos

    2008-10-01

    Full Text Available A produtividade em sistemas agrícolas de subsistência depende do nível de fertilidade natural do solo. Em condições de relevo forte ondulado, espera-se que a fertilidade do solo se modifique não apenas pelo tipo de uso mas, também, devido à sua posição no relevo. Para avaliar essas modificações, 260 amostras simples de solo (0-20 cm da microbacia Vaca Brava, PB, representando combinações de três usos do solo, cinco posições no relevo e cinco classes texturais, foram analisadas quanto aos teores de P disponível, bases e acidez trocáveis. Ca e Mg compreenderam 75-80% dos cátions trocáveis, K e Na, de 10 a 15%, e H+Al, 10%; o valor de pH médio foi 5,5, enquanto P Mehlich-1 foi, em média, 3,8 mg kg-1 solo. Apesar dos efeitos significativos (p Productivity in subsistence agricultural systems relies on natural soil fertility levels. Under strongly undulated relief conditions, it is expected that soil fertility will be determined not only by land use, but also by the position in the landscape. To study these relationships 260 single soil samples (0-20 cm from the Vaca Brava watershed, Paraiba, representing combinations of three land uses, five positions in the landscape and five textures were analyzed for extractable P, exchangeable bases and soil acidity. Ca and Mg comprised 75-80% of exchangeable cations, K and Na between 10 and 15% and H+Al 10%. The average pH was 5.5, while extractable P (Mehlich-1 averaged 3.8 mg kg-1 soil. Although land use, relief and texture exerted significant effects (p < 0.05 upon certain nutrient concentrations, in a broad sense the watershed appeared relatively uniform. The main effect of land use resulted from the use of animal manure in areas of subsistence agriculture and fodder, which were preferentially located at the base of stopes and low lands positions. Approximately 80% of the samples were low in extractable P, while 70% had medium levels of extractable K. However, when available K was

  18. Engaging with community-based public and private mid-level providers for promoting the use of modern contraceptive methods in rural Pakistan: results from two innovative birth spacing interventions.

    Science.gov (United States)

    Azmat, Syed Khurram; Hameed, Waqas; Hamza, Hasan Bin; Mustafa, Ghulam; Ishaque, Muhammad; Abbas, Ghazunfer; Khan, Omar Farooq; Asghar, Jamshaid; Munroe, Erik; Ali, Safdar; Hussain, Wajahat; Ali, Sajid; Ahmed, Aftab; Ali, Moazzam; Temmerman, Marleen

    2016-03-17

    Family planning (FP) interventions aimed at reducing population growth have negligible during the last two decades in Pakistan. Innovative FP interventions that help reduce the growing population burden are the need of the hour. Marie Stopes Society--Pakistan implemented an operational research project--'Evidence for Innovating to Save Lives', to explore effective and viable intervention models that can promote healthy timing and spacing of pregnancy in rural and under-served communities of Sindh, Punjab and Khyber Pakhtunkhwa provinces of Pakistan. We conducted a quasi-experimental (pre- and post-intervention with control arm) study to assess the effectiveness of each of the two intervention models, (1) Suraj model (meaning 'Sun' in English), which uses social franchises (SF) along with a demand-side financing (DSF) approach using free vouchers, and (2) Community Midwife (CMW) model, in promoting the use of modern contraceptive methods compared to respective controls. Baseline and endline cross-sectional household surveys were conducted, 24 months apart, by recruiting 5566 and 6316 married women of reproductive age (MWRA) respectively. We used Stata version 8 to report the net effect of interventions on outcome indicators using difference-in-differences analysis. Multivariate Cox proportional hazard regression analysis was used to assess the net effect of the intervention on current contraceptive use, keeping time constant and adjusting for other variables in the model. The Suraj model was effective in significantly increasing awareness about FP methods among MWRA by 14% percentage points, current contraceptive use by 5% percentage points and long term modern method--intrauterine device (IUD) use by 6% percentage points. The CMW model significantly increased contraceptive awareness by 28% percentage points, ever use of contraceptives by 7% percentage points and, IUD use by 3% percentage points. Additionally the Suraj intervention led to a 35% greater prevalence

  19. Study of geological details towards feasibility of uranium project: Indian case studies

    International Nuclear Information System (INIS)

    Sarangi, A.

    2014-01-01

    towards deciding the mining (e.g. stoping) method. Large ore samples generated during the process helps in detailed pilot plant studies and operation of the plant on continuous mode while fine-tuning all process related steps. The period of exploratory mining is further utilised in locating and planning infrastructure needs, preparation of different reports for regulatory clearances and generating public opinion in favour of uranium mining. All Indian uranium deposits have gone through glorious phase of exploratory mining generating large volume of data which are of immense value to the operators during the life of the mines and plants. (author)

  20. Magma traps and driving pressure: consequences for pluton shape and emplacement in an extensional regime

    Science.gov (United States)

    Hogan, John P.; Price, Jonathan D.; Gilbert, M. Charles

    1998-09-01

    intrusion must be created by other mechanisms (e.g. stoping). (5) Subvertical sheets (i.e. dikes) form when the magma driving pressure is less than the lithostatic load at the level of emplacement.

  1. Vouchers in Fragile States: Reducing Barriers to Long-Acting Reversible Contraception in Yemen and Pakistan.

    Science.gov (United States)

    Boddam-Whetham, Luke; Gul, Xaher; Al-Kobati, Eman; Gorter, Anna C

    2016-08-11

    In conflict-affected states, vouchers have reduced barriers to reproductive health services and have enabled health programs to use targeted subsidies to increase uptake of specific health services. Vouchers can also be used to channel funds to public- and private-service providers and improve service quality. The Yamaan Foundation for Health and Social Development in Yemen and the Marie Stopes Society (MSS) in Pakistan-both working with Options Consultancy Services-have developed voucher programs that subsidize voluntary access to long-acting reversible contraceptives (LARCs) and permanent methods (PMs) of family planning in their respective fragile countries. The programs focus on LARCs and PMs because these methods are particularly difficult for poor women to access due to their cost and to provider biases against offering them. Using estimates of expected voluntary uptake of LARCs and PMs for 2014 based on contraceptive prevalence rates, and comparing these with uptake of LARCs and PMs through the voucher programs, we show the substantial increase in service utilization that vouchers can enable by contributing to an expanded method choice. In the governorate of Lahj, Yemen, vouchers for family planning led to an estimated 38% increase in 2014 over the expected use of LARCs and PMs (720 vs. 521 expected). We applied the same approach in 13 districts of Punjab, Khyber Pakhtunkhwa (KPK), and Sindh provinces in Pakistan. Our calculations suggest that vouchers enabled 10 times more women than expected to choose LARCs and PMs in 2014 in those areas of Pakistan (73,639 vs. 6,455 expected). Voucher programs can promote and maintain access to family planning services where existing health systems are hampered. Vouchers are a flexible financing approach that enable expansion of contraceptive choice and the inclusion of the private sector in service delivery to the poor. They can keep financial resources flowing where the public sector is prevented from offering services

  2. FEATURES OF DRILLING-AND-BLASTING AT CONSTRUCTION OF BESKIDSKIY TUNNEL

    Directory of Open Access Journals (Sweden)

    V. D. Petrenko

    2016-10-01

    Full Text Available Purpose. In this article it is necessary to analyze the possibility of developing technology and increasing its efficiency during the Beskidskiy tunnel construction in difficult engineering and geological conditions. Methodology. The authors have performed analysis of the technological level of mining and construction works, new technique, equipment and production. One of the important issues of blasting operation is to ensure the seismic safety, acting at a distance of 30 m in the axes of single-track tunnel, as the distance to it will be 20 m from the nearest charge in the laying tunnel. This problem was solved by applying the combined blasting of blast-hole charges with delay-action and long-delay ways. Herewith the total mass of charges in the stope was divided into three groups, in which the first group is exploded by short-delay firing with, and the second one is exploded by short-delay firing too with intervals of 200…400 ms, the third is exploded by long-delay blasting at intervals of 500…10000 ms. The combined blasting of short-delay charges and delay action ones let significantly reduce seismic action at a mass explosion of charges when driving of double-track railway tunnel of a large cross-section. Findings. The paper presents the developed technology model, describing dependence of the machines from engineering and geological conditions. The methodology of drilling and blasting works at the construction of the tunnel callote and stross as well as a technique of arrangement determination and intervals of shot-delay and delay blasting of blasthole explosive charges was developed. Maximum permissible concentration of gases and vapours at blasting was presented. The calculations showed that the maximum level of gas contamination of the working area in Beskidskiy tunnel is achieved at blast operations. In accordance with this ventilation of the tunnel when driving is carried out by independent systems with mechanical ventilation by

  3. Using restored cross sections to evaluate magma emplacement, White Horse Mountains, Eastern Nevada, U.S.A.

    Science.gov (United States)

    Marko, Wayne T.; Yoshinobu, Aaron S.

    2011-03-01

    serial cross sections oriented perpendicular to the pluton contact, the aureole was shortened approximately 54% during emplacement. Extrapolating this shortening value over the exposed area of the pluton indicates that approximately 48% of the exposed pluton area may be accounted for by the restoration. Therefore, host rocks must have been displaced out of the map plane and likely downward based on geometrical constraints provided by the cross sections. The preferred emplacement model requires in-situ chamber dilation accommodated by ductile deflection of host rocks followed by fracturing and removal of the aureole rocks via cauldron subsidence and/or stoping.

  4. Safety and effectiveness of termination services performed by doctors versus midlevel providers: a systematic review and analysis

    Directory of Open Access Journals (Sweden)

    Free C

    2013-01-01

    Full Text Available Thoai D Ngo,1,2 Min Hae Park,1 Caroline Free21Research, Monitoring and Evaluation Team, Health System Department, Marie Stopes International, UK; 2Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UKObjective: Training midlevel providers (MLPs to conduct surgical abortions and manage medical abortions has been proposed as a way to increase women's access to safe abortion. This paper reviews the evidence that compares the effectiveness and safety of abortion procedures administered by MLPs versus doctors.Methods: A systematic search was conducted of published trials and comparison studies assessing the effectiveness and/or safety of abortion provided by MLPs compared to doctors. The Cochrane Central Register of Controlled Trials, EMBASE, MEDLINE, and Popline were searched. The primary outcomes of interest were: (1 incomplete or failed abortion; and (2 measures of safety (adverse events and complications of abortion procedures administered by MLPs and doctors. Odds ratios (ORs and their 95% confidence intervals (CIs were calculated for each study. Data were synthesized in a narrative fashion.Findings: Five studies were included in this review (n = 8539 women, comprising two randomized controlled trials (RCTs (n = 3821 and three prospective cohort studies (n = 4718. In total, 4198 women underwent a procedure administered by an MLP, and 4341 women underwent a physician-administered procedure. Studies took place in the US, Nepal, South Africa, Vietnam, and India. Four studies used surgical abortion with maximum gestational ages ranging from 10 to 16+ weeks, while a medical abortion study had gestational ages up to 9 weeks. In RCTs, the effect estimates for incomplete or failed abortion for procedures performed by MLPs compared with doctors were OR = 2.00 (95% CI 0.85–4.68 for surgical abortion, and OR = 0.69 (95% CI 0.34–1.37 for medical abortion. Complications were rare among both provider

  5. Granite ascent and emplacement during contractional deformation in convergent orogens

    Science.gov (United States)

    Brown, Michael; Solar, Gary S.

    1998-09-01

    Based on a case study in the Central Maine Belt of west-central Maine, U.S.A., it is proposed that crustal-scale shear zone systems provide an effective focussing mechanism for transfer of granite melt through the crust in convergent orogens. During contractional deformation, flow of melt in crustal materials at depths below the brittle-plastic transition is coupled with plastic deformation of these materials. The flow is driven by pressure gradients generated by buoyancy forces and tectonic stresses. Within the oblique-reverse Central Maine Belt shear zone system, stromatic migmatite and concordant to weakly discordant irregular granite sheets occur in zones of higher strain, which suggests percolative flow of melt to form the migmatite leucosomes and viscous flow of melt channelized in sheet-like bodies, possibly along fractures. Cyclic fluctuations of melt pressure may cause instantaneous changes in the effective permeability of the flow network if self-propagating melt-filled tensile and/or dilatant shear fractures are produced due to melt-enhanced embrittlement. Inhomogeneous migmatite and schlieric granite occur in zones of lower strain, which suggests migration of partially-molten material through these zones en masse by granular flow, and channelized flow of melt carrying entrained residue. Founded on the Central Maine Belt case study, we develop a model of melt extraction and ascent using the driving forces, stress conditions and crustal rheologies in convergent, especially transpressive orogens. Ascent of melt becomes inhibited with decreasing depth as the solidus is approached. For intermediate a(H 2O) muscovite-dehydration melting, the water-saturated solidus occurs between 400 and 200 MPa, near the brittle-plastic transition during high- T-low- P metamorphism, where the balance of forces favors (sub-) horizontal fracture propagation. Emplacement of melt may be accommodated by ductile flow and/or stoping of wall rock, and inflation may be accommodated

  6. Estimating the hypothetical dual health impact and cost-effectiveness of the Woman’s Condom in selected sub-Saharan African countries

    Directory of Open Access Journals (Sweden)

    Mvundura M

    2015-03-01

    Full Text Available Mercy Mvundura, Neeti Nundy, Maggie Kilbourne-Brook, Patricia S Coffey Technology Solutions Global Program, PATH, Seattle, WA, USA Background: Female condoms are the only currently available woman-initiated option that offers dual protection from pregnancy and sexually transmitted infections, including HIV. The Woman’s Condom is a new female condom designed to provide dual protection and to be highly pleasurable and acceptable. Objective: We sought to estimate the potential dual health impact and cost-effectiveness of a Woman’s Condom distribution program in 13 sub-Saharan African countries with HIV prevalence rates >4% among adults aged 15–49 years. We used two separate, publicly available models for this analysis, the Impact 2 model developed by Marie Stopes International and the Population Services International disability-adjusted life years (DALY calculator program. We estimated the potential numbers of pregnancies and DALYs averted when the Woman’s Condom is used as a family planning method and the HIV infections and DALYs averted when it is used as an HIV prevention method. Results: Programming 100,000 Woman’s Condoms in each of 13 countries in sub-Saharan Africa during a 1-year period could potentially prevent 194 pregnancies and an average of 21 HIV infections in each country. When using the World Health Organization CHOosing Interventions that are Cost-Effective (WHO-CHOICE criteria as a threshold to infer the potential cost-effectiveness of the Woman’s Condom, we found that the Woman’s Condom would be considered cost-effective. Conclusion: This was a first and successful attempt to estimate the impact of dual protection of female condoms. The health impact is greater for the use of the Woman’s Condom as an HIV prevention method than for contraception. Dual use of the Woman’s Condom increases the overall health impact. The Woman’s Condom was found to be very cost-effective in all 13 countries in our sample. Keywords

  7. Hydrostatic Water Level Systems At Homestake DUSEL

    Science.gov (United States)

    Stetler, L. D.; Volk, J. T.

    2009-12-01

    correlated to Fermilab instruments (for comparative analysis) and others in independent arrays. All tiltmeter data will be analyzed with water reduction data (currently being collected from the #6 winze as the mine is dewatered) and data from rock stress/fracture experiments to document net ground settling due to dewatering, potential collapse of stope areas and renewed excavation activities.

  8. Social franchising and vouchers to promote long-term methods of family planning in rural Pakistan: a qualitative stocktaking with stakeholders.

    Science.gov (United States)

    Azmat, Syed Khurram; Mustafa, Ghulam; Hameed, Waqas; Asghar, Jamshaid; Ahmed, Aftab; Shaikh, Babar T

    2013-04-01

    The overall use of modern contraception in Pakistan is quite low, especially in rural areas. Several studies have demonstrated the effectiveness of social franchising (SF) approaches in increasing access to modern contraception and improving the quality of healthcare in resource-poor areas in Asia and Africa. Drawing on best practices in SF, the Marie Stopes Society (MSS) implemented an SF model in certain rural areas of Pakistan to increase access to affordable and quality family planning (FP) services. The model was branded as Suraj (sun) and complemented with an innovative voucher scheme for intrauterine contraceptive devices (IUCDs). This paper describes the perspectives of Suraj clients, field workers mobilization (FWMs), and providers on various components of the Suraj model. A qualitative exploratory study was conducted in six randomly selected intervention districts in the Sindh and Punjab provinces. Data were collected using focus group discussions (FGDs) with clients and in-depth interviews (IDIs) with providers and FWMs. Data were manually analyzed using constant comparison and the thematic analysis approach. Clients showed positive attitudes towards modern contraceptive methods and identified Suraj FWMs and signboards as sources of information. Almost all clients reported IUCDs as effective methods as they have manageable side effects and require fewer visits to clinics. They spoke highly of voucher schemes as these enabled them to avail free IUCD services. Clients also appreciated many components of Suraj clinics, including cleanliness, privacy, confidentiality, the sterilization of instruments, and courteous Suraj providers and FWMs. Most Suraj providers said that IUCD insertion and infection-prevention training enhanced their ability to provide IUCD services and increased their standing in local communities. They reported that the role of FWMs was crucial in mobilizing the community and increasing their FP clientele. The FWMs said that attitudes

  9. Rock mass response to strong ground motion generated by mining induced seismic events and blasting observed at the surface of the excavations in deep level gold mines in South Africa

    Science.gov (United States)

    Milev, Alexander; Durrheim, Ray; Ogasawara, Hiroshi

    2014-05-01

    The strong ground motion generated by mining induced seismic events was studied to characterize the rock mass response and to estimate the site effect on the surface of the underground excavations. A stand-alone instruments, especially designed for recording strong ground motions, were installed underground at a number of deep level gold mines in South Africa. The instruments were recording data at the surface of the stope hangingwalls. A maximum value of 3 m/s was measured. Therefore data were compared to the data recorded in the solid rock by the mine seismic networks to determine the site response. The site response was defined as the ratio of the peak ground velocity measured at the surface of the excavations to the peak ground velocity inferred from the mine seismic data measured in the solid rocks. The site response measured at all mines studied was found to be 9 ± 3 times larger on average. A number of simulated rockbursts were conducted underground in order to estimate the rock mass response when subjected to extreme ground motion and derive the attenuation factors in near field. The rockbursts were simulated by means of large blasts detonated in solid rock close to the sidewall of a tunnel. The numerical models used in the design of the simulated rockbursts were calibrated by small blasts taking place at each experimental site. A dense array of shock type accelerometers was installed along the blasting wall to monitor the attenuation of the strong ground motion as a function of the distance from the source. The attenuation of the ground motion was found to be proportional to the distance from the source following R^-1.1 & R^-1.7 for compact rock and R^-3.1 & R^-3.4 for more fractured rock close to the surface of the tunnel. In addition the ground motion was compared to the quasi-static deformations taking place around the underground excavations. The quasi-static deformations were measured by means of strain, tilt and closure. A good correspondence

  10. An eco-friendly method for heavy metal removal from mine tailings.

    Science.gov (United States)

    Arab, Fereshteh; Mulligan, Catherine N

    2018-03-29

    One of the serious environmental problems that society is facing today is mine tailings. These byproducts of the process of extraction of valuable elements from ores are a source of pollution and a threat to the environment. For example, mine tailings from past mining activities at Giant Mines, Yellowknife, are deposited in chambers, stopes, and tailing ponds close to the shores of The Great Slave Lake. One of the environmentally friendly approaches for removing heavy metals from these contaminated tailing is by using biosurfactants during the process of soil washing. The objective of this present study is to investigate the effect of sophorolipid (SL) concentration, the volume of washing solution per gram of medium, pH, and temperature on the efficiency of sophorolipids in removing heavy metals from mine tailings. It was found that the efficiency of the sophorolipids depends on its concentration, and is greatly affected by changes in pH, and temperature. The results of this experiment show that increasing the temperature from 15 to 23 °C, while using sophorolipids, resulted in an increase in the removal of iron, copper, and arsenic from the mine tailing specimen, from 0.25, 2.1, and 8.6 to 0.4, 3.3, and 11.7%. At the same time, increasing the temperature of deionized water (DIW) from 15 to 23 °C led to an increase in the removal of iron, copper, and arsenic from 0.03, 0.9, and 1.8 to 0.04, 1.1, and 2.1%, respectively. By increasing temperature from 23 to 35 °C, when using sophorolipids, 22% reduction in the removal of arsenic was observed. At the same time while using DI water as the washing solution, increasing temperature from 23 to 35 °C resulted in 6.2% increase in arsenic removal. The results from this present study indicate that sophorolipids are promising agents for replacing synthetic surfactants in the removal of arsenic and other heavy metals from soil and mine tailings.

  11. ENDOTHELIAL PROTECTIVE EFFECTS OF KLYMADINON IN EXPERIMENTAL OVARIECTOMY

    Directory of Open Access Journals (Sweden)

    A. M. Anishchenko

    2013-01-01

    Full Text Available A Endothelial protective and antithrombogenic effects of Cimicifuga racemosa standardized extract (Klimadynon, Bionorica, Germany in comparison with ethinylestradiol in experimental ovariectomy were investigated. Extract of Cimicifuga racemosa (klimadynon contents phytoestrogens, that was the basis for studying of its effects in hypoestrogenic conditions for the purpose of prophylaxis and treatment of cardiovascular complications in climacteric syndrome as an alternatively of hormonal replacement therapy.The course administration of klimadynon (100 mg/kg p.o. daily during 14 days decelerated the formation of intravascular thrombosis which was initiated by application of 10% FeCb solution on carotid artery. The ethinylestradiol in this conditions intensified prothrombogenic effect of application of 10% FeCh: blood flow in carotid artery stoped to 5 minutes of experiment and mass of the thrombus was on 28% more, than in control rats. For studying of possible mechanisms antithrombogenic action of klimadynon antiplatelet and vasodilator activity of endothelium were studied in rats after bilateral ovariectomy in comparison with effects of ethinylestradiol (25 µg/kg p.o. daily during 14 days. Treatment with klimadynon as well as ethinylestradiol increased the antiplatelet activity of endothelium, restoring its activity to level in sham-operated animals. The endothelium-dependent and endothelium-independence vasodilation by using of acetylcholine (5 µg/kg and of sodium nitroprusside (30 µg/kg. respectively, were investigated. Coefficient of endothelium dysfunctions (CED was estimated as ratio: area over curve of arterial pressure after sodium nitroprusside intravenous injection to value of this index after injection of acetylcholine. In rats after bilateral ovariectomy CED was increased by 66% in comparison with CED value in sharm-operated rats. The klimadynon and ethinylestradiol treatment decreased CED on 42% and 28% correspondingly in comparison

  12. La mirada de los porteros de fútbol sala ante diferentes tipos de respuesta motriz. [Futsal goalkeepers’ gaze behavior with different type of motor response].

    Directory of Open Access Journals (Sweden)

    José Luis Graupera Sanz

    2013-07-01

    Full Text Available En este estudio se exploró y analizó el comportamiento visual de un grupo de porteros expertos de fútbol sala con el objetivo de comprobar cómo el tipo de respuesta motriz solicitada influía en su comportamiento visual. Participaron 4 porteros a los que se les presentó un total de 48 clips de vídeo en una pantalla a tamaño real, bajo dos condiciones de respuesta: con movimiento de parada y sin movimiento de parada. Se registró su mirada con el pupilómetro ASL Mobile Eye durante dos condiciones de tiro de penalti. Se analizó la mirada en el intervalo de -250 a 205 ms en torno al disparo. Los resultados mostraron que cuando respondían con la acción habitual de parada, solo se encontraron fijaciones en la mitad de los casos, estas fijaciones eran de corta duración y localizadas principalmente en la zona del suelo justo enfrente del balón. Por el contrario, cuando se mantenían en posición estática, su mirada se dirigía hacia la zona entre el balón y la pierna de apoyo, empleando fijaciones de una duración más larga. Se puede concluir que el comportamiento visual fue diferente entre las dos condiciones como resultado de la adaptación a las demandas espacio-temporales específicas de cada condición, ya que el grado de movimiento en la respuesta solicitada tuvo influencia en el comportamiento visual asociado.AbstractThis study explored and analyzed the visual behavior of a group of experts from futsal goalkeepers in order to check on if the type of requested motor response influenced their visual behavior. Four goalkeepers were presented with a total of 48 video clips on a real-size screen, under two response conditions: with and without movement. Gaze was recorded with the ASL Mobile Eye eyetracker, and was analyzed in the range of -250 to 205 ms around the penalty kick. The results showed that when responding with the usual stoping action, fixations were found only in the half of the cases, being of short duration, and

  13. Developing mHealth Messages to Promote Postmenstrual Regulation Contraceptive Use in Bangladesh: Participatory Interview Study.

    Science.gov (United States)

    Eckersberger, Elisabeth; Pearson, Erin; Andersen, Kathryn; Hossain, Altaf; Footman, Katharine; Biswas, Kamal Kanti; Nuremowla, Sadid; Reiss, Kate

    2017-12-14

    Abortions are restricted in Bangladesh, but menstrual regulation is an approved alternative, defined as a procedure of regulating the menstrual cycle when menstruation is absent for a short duration. Use of contraception after menstrual regulation can reduce subsequent unintended pregnancy, but in Bangladesh, the contraceptive method mix is dominated by short-term methods, which have higher discontinuation and failure rates. Mobile phones are a channel via which menstrual regulation clients could be offered contraceptive support after leaving the clinic. This study aimed to support the development of a mobile phone intervention to support postmenstrual regulation family planning use in Bangladesh. It explored what family planning information women want to receive after having a menstrual regulation procedure, whether they would like to receive this information via their mobile phone, and if so, what their preferences are for the way in which it is delivered. We conducted participatory interviews with 24 menstrual regulation clients in Dhaka and Sylhet divisions in Bangladesh. Women were recruited from facilities in urban and peri-urban areas, which included public sector clinics supported by Ipas, an international nongovernmental organization (NGO), and NGO clinics run by Marie Stopes. Main themes covered in the interviews were factors affecting the use of contraception, what information and support women want after their menstrual regulation procedure, how respondents would prefer to receive information about contraception, and other key issues for mobile health (mHealth) interventions, such as language and privacy. As part of the in-depth interviews, women were shown and played 6 different messages about contraception on the research assistant's phone, which they were given to operate, and were then asked to give feedback. Women were open to both receiving messages about family planning methods on their mobile phones and talking to a counselor about family

  14. Building The Bigger Picture - Using a field study geology programme to link and contextualise classroom topics.

    Science.gov (United States)

    Allen, Lesley

    2013-04-01

    , stoping and faulting visible. Site 4 - Polurrian Cove. Western end of boundary thrust fault between metamorphosed subterranean lava flows (hornblende schists)above and crustal Devonian slates below can be observed. Site 5 - Coverack Cove to Godrevy Cove. The beach rocks change from olivine rich serpentinised peridotite to gabbro as you move across the Moho boundary zone. Further along the coast at Dean Point, dolerite dykes are quarried and basalt dykes are found at neighbouring Godrevy Cove - the complete ophiolite sequence in a few miles! Site 6 - Holmans Mine. Camborne School of Mines' training mine where students can experience blasting and see methods of rock stabilisation. They can also see mineral veins in situ underground and investigate mining techniques. Site 7 - Carnon Valley. Once known as the 'richest square mile in the World' due to the amount of tin and copper being produced. The Wheal Jane pollution incident (1992) caused widespread alarm and was dealt with by chemical and biological treatment systems still in operation. Historical and current tailings dams can be seen and compared, and the ecology of environmentally damaged ground observed. Mine dumps still yield mineral specimens and the streams are still acidic after heavy rain.

  15. [The preparation and characterization of fine dusts carried out in the Clinica del Lavoro di Milano in support of experimental studies].

    Science.gov (United States)

    Occella, E; Maddalon, G; Peruzzo, G F; Foà, V

    1999-01-01

    pestles and rotating drum mills with autogenic grinding load were used for grinding: the size of the treated samples was reduced to 0.05 mm and an extremely fine fraction was extracted, smaller than 7-10 microns, which was used for pneumoconioses research. The characterization of the dust produced was in any case achieved by means of preliminary examination under the optical microscope (polarized light, sometimes supplemented with phase contrast), followed by quantitative analysis using chemical/petrographic, chemical diffraction or, more commonly, petrographic/diffraction techniques. Microscopic examination, if necessary supplemented with photo-micrography, was also used for particle size control, for numerical counting and subsequent reference to weight proportion. For all operational procedures the essential data on instruments and methods are reported. During studies on production, separation of fine dusts and their characterization, partly performed with support from the European Community (EEC/European Coal and Steel Commission), the following topics in particular were addressed: connections between particle size and free silica content in the measurable dust size fraction of the grinding products and in airborne dusts; characteristics of the dusts and risk indices in Italian iron and pyrite mines; possibility of abatement of the ultrafine classes of airborne dusts in pneumatically filled stopes by the addition of salts; comparison of the latest dust selectors used within the European Community; influence of the grinding methods on the results of fibrous and soft mineral measurement using X-ray diffraction analysis.

  16. The incidence of abortion and unintended pregnancy in India, 2015.

    Science.gov (United States)

    Singh, Susheela; Shekhar, Chander; Acharya, Rajib; Moore, Ann M; Stillman, Melissa; Pradhan, Manas R; Frost, Jennifer J; Sahoo, Harihar; Alagarajan, Manoj; Hussain, Rubina; Sundaram, Aparna; Vlassoff, Michael; Kalyanwala, Shveta; Browne, Alyssa

    2018-01-01

    Reliable information on the incidence of induced abortion in India is lacking. Official statistics and national surveys provide incomplete coverage. Since the early 2000s, medication abortion has become increasingly available, improving the way women obtain abortions. The aim of this study was to estimate the national incidence of abortion and unintended pregnancy for 2015. National abortion incidence was estimated through three separate components: abortions (medication and surgical) in facilities (including private sector, public sector, and non-governmental organisations [NGOs]); medication abortions outside facilities; and abortions outside of facilities and with methods other than medication abortion. Facility-based abortions were estimated from the 2015 Health Facilities Survey of 4001 public and private health facilities in six Indian states (Assam, Bihar, Gujarat, Madhya Pradesh, Tamil Nadu, and Uttar Pradesh) and from NGO clinic data. National medication abortion drug sales and distribution data were obtained from IMS Health and six principal NGOs (DKT International, Marie Stopes International, Population Services International, World Health Partners, Parivar Seva Santha, and Janani). We estimated the total number of abortions that are not medication abortions and are not obtained in a health facility setting through an indirect technique based on findings from community-based study findings in two states in 2009, with adjustments to account for the rapid increase in use of medication abortion since 2009. The total number of women of reproductive age and livebirth data were obtained from UN population data, and the proportion of births from unplanned pregnancies and data on contraceptive use and need were obtained from the 2015-16 National Family Health Survey-4. We estimate that 15·6 million abortions (14·1 million-17·3 million) occurred in India in 2015. The abortion rate was 47·0 abortions (42·2-52·1) per 1000 women aged 15-49 years. 3·4 million

  17. TEMU KEMBALI INFORMASI BIBLIOGRAFI DENGAN BAHASA ALAMI PADA FIELD JUDUL DAN SUFJEK (Studi Efektivitas Katalog Induk Terpasang Perpustakaan UGM

    Directory of Open Access Journals (Sweden)

    Janu Saptari

    2015-12-01

    Full Text Available This Research aim to know the retrieval effectiveness on Online Union Catalog of UGM Library, index pattern at data bases, knowing which's more effective of searching at entri oftitle and subjec and also to know the cause ofeffectiveness difference retrieval at the both entri. Along with growth and information accretion, the main problem have shifted from way of accessing information become to chosen the relevant information with its requirement. Information retrieval is not possible to be done in the manual system, because very big information corps and non-stoped growing larger. The information retrieval system is very needed to to assist the consumer in finding information. One of the information retrieval system is online union catalog. With the online union catalog, by users easily can look for the book title, pickings of research and other documentation of library where from and any time. Getting a number of relevant document with the requirement represent the crux in the searching activity, and effectiveness from online union catalog is this represent the key. Effectiveness from a system influenced by a lot of component which each other related/relevant like: quality of input metadata in data bases, index, searching strategy, ability of system application and keyword election. A system told effective if the system can find more amount document/ appropriate information of request by precission /high accuracy. Research done by testing search at online union catalog to use the natural language keyword. Keyword inclusion done at entri of title and entri subjek. Keyword of taken as sampel come from one of title matakuliah of each; every faculty in UGM. From each; every the topic then translated /formulated into 4 natural language keyword. Data obtained is grouped by relevant level. From the acquirement data; then analysed with the test ofnonparametrik Mann Whitney. From processing data got by conclusion that ratio of retrieval at title entries

  18. Síndrome de Chilaiditi associada a volvo de cólon sigmóide: relato de caso Chilaiditi's Syndrome with sigmoid colon volvulus: case report

    Directory of Open Access Journals (Sweden)

    Marcelo Wilson Rocha Almeida

    2006-12-01

    Full Text Available INTRODUÇÃO: Este estudo tem como objetivo relatar um caso de Síndrome de Chilaiditi associada a volvo de cólon sigmóide. RELATO DE CASO: Paciente masculino, branco, 51 anos, admitido no Pronto-Socorro de Pelotas queixando parada da eliminação de gases e fezes, dor abdominal difusa com distensão e inapetência, aceitando somente líquido. Tem diagnóstico de retardo mental e constipação intestinal crônica. Foi realizado Rx de abdome agudo, sendo evidenciada distensão difusa de cólon, e sinais sugestivos de volvo de sigmóide com imagem de cólon transverso entre o fígado e o diafragma. O paciente foi submetido a laparotomia exploradora, sendo constatado volvo de sigmóide, megacólon difuso e interposição do cólon transverso entre o fígado e o diafragma. Procedeu-se a colectomia subtotal, com colostomia terminal em cólon ascendente e fechamento do reto remanescente, recebendo alta no 9º dia. DISCUSSÃO: A interposição do cólon entre o fígado e a cúpula diafragmática (síndrome de Chilaiditi, associada a volvo de cólon sigmóide, constitui causa rara de abdome agudo obstrutivo, embora o volvo de sigmóide seja uma das principais causas de obstrução intestinal mecânica no Brasil. Geralmente o tratamento é clínico, porém se associado a complicações o tratamento é cirúrgico.INTRODUCTION: This study aims at reporting a case of Chilaiditi Syndrome associated to sigmoid colon volvulus. CASE REPORT: Male patient, white, 51 years old, arrives at an emergency hospital in Pelotas with complaints of stoping the elimination of gases, diffuse abdominal pain, increase of abdominal volume, gradual and progressive inappetence, accepting only liquid. He is diagnosed with mental retardation and a situation of intestinal constipation. An acute abdomen Rx highlighted a diffuse colon distension, suggestive of sigmoid volvulus with tranversum colon image between the liver and the diaphragm. The patient was submitted to exploratory

  19. Organic petrography:An approach for identification of maceral groups in Gheshlagh coal area, Eastern Alborz

    Directory of Open Access Journals (Sweden)

    Tahereh Rabani

    2016-07-01

    Full Text Available Introduction Maceral is a term to introduce organic components visible under a microscope (Stopes, 1935. The physical and chemical characteristics of macerals such as elemental composition, moisture content, hardness, density and petrographic characteristics differ. The differences in the physical and chemical characteristics of macerals are reflected in their industrial behavior.(Parkash, 1985. Petrographic analysis provides information on the various physical components of coals (Suwarna and Hemanto, 2007 and determination of quality of coal, coalification rate, composition and characteristics of coke and paleoenvironmental deposition (Taylor et al., 1998. Sampling and methodology Coal samples were collected from freshly mined coal from 11 coal seams of 4 active coal mines (Cheshlagh, Zemestan Yourt, Narges Chal and Cheshmehsaran for organic petrography in the Gheshlagh coal deposits. All samples were collected and stored in plastic bags to prevent contamination and weathering. Samples were prepared for microscopic analysis by reflected light following ASTM Standard procedure D2797-04. For microscopic study, coal samples were crushed to1-mm size fraction (18 mesh size, mounted in epoxy resin and polished. Three polished samples were prepared for each coal seam. The petrographic composition was obtained by maceral analyses under standard conditions (ISO 7404/3, 2009, for maceral analysis. Maceral point counting (based on 400 points analyses were performed using an Olympus BX51 reflected light microscope. The terminology used to identify and describe the organic matter particles is the one proposed by the International Committee for Coal and Organic Petrology (ICCP, 1998; ICCP, 2001; Scott and Glasspool, 2007; Taylor et al., 1998; Stach et al., 1982; Hower et al., 2009; Hower and Wagner, 2012. Organic petrography of theGheshlagh coal seams The vitrinite maceral group is dominant in all coal seams (66.2 to 87.2 vol.% and includes collodetrinite

  20. GEOLOGIC SCREENING CRITERIA FOR SEQUESTRATION OF CO2 IN COAL: QUANTIFYING POTENTIAL OF THE BLACK WARRIOR COALBED METHANE FAIRWAY, ALABAMA

    Energy Technology Data Exchange (ETDEWEB)

    Jack C. Pashin; Richard E. Carroll; Richard H. Groshong, Jr.; Dorothy E. Raymond; Marcella McIntyre; J. Wayne Payton

    2003-01-01

    Sequestration of CO{sub 2} in coal has potential to reduce greenhouse gas emissions from coal-fired power plants while enhancing coalbed methane recovery. Data from more than 4,000 coalbed methane wells in the Black Warrior basin of Alabama provide an opportunity to quantify the carbon sequestration potential of coal and to develop a geologic screening model for the application of carbon sequestration technology. This report summarizes stratigraphy and sedimentation, structural geology, geothermics, hydrology, coal quality, gas capacity, and production characteristics of coal in the Black Warrior coalbed methane fairway and the implications of geology for carbon sequestration and enhanced coalbed methane recovery. Coal in the Black Warrior basin is distributed among several fluvial-deltaic coal zones in the Lower Pennsylvanian Pottsville Formation. Most coal zones contain one to three coal beds that are significant targets for coalbed methane production and carbon sequestration, and net coal thickness generally increases southeastward. Pottsville strata have effectively no matrix permeability to water, so virtually all flow is through natural fractures. Faults and folds influence the abundance and openness of fractures and, hence, the performance of coalbed methane wells. Water chemistry in the Pottsville Formation ranges from fresh to saline, and zones with TDS content lower than 10,000 mg/L can be classified as USDW. An aquifer exemption facilitating enhanced recovery in USDW can be obtained where TDS content is higher than 3,000 mg/L. Carbon dioxide becomes a supercritical fluid above a temperature of 88 F and a pressure of 1,074 psi. Reservoir temperature exceeds 88 F in much of the study area. Hydrostatic pressure gradients range from normal to extremely underpressured. A large area of underpressure is developed around closely spaced longwall coal mines, and areas of natural underpressure are distributed among the coalbed methane fields. The mobility and

  1. Final report of the drive of the TASS-tunnel; Slutrapport fraan drivningen av TASS-tunneln

    Energy Technology Data Exchange (ETDEWEB)

    Karlzen, Rickard; Johansson, Emmeli (Svensk Kaernbraenslehantering AB (Sweden))

    2010-05-15

    , with good result of visible drill holes. The introduction of electronic detonators also took care of the problem of cut-off holes, which pretty much disappeared and re-blasting was minimized. The EDZ was evaluated in /Olsson et al. 2009/ and shows that no continuous EDZ was found. The performed drilling has been evaluated by looking at the drilling accuracy and precision. Geodetic surveying was performed of the collaring of 15-20 evenly distributed drill holes in the contour; all the drill holes in the floor and a varying amount of helpers and stope holes in each round. Afterwards the endpoints were calculated. The resulting data has then been evaluated and even compared with obtained data of the location of collaring and endpoints from the jumbo

  2. Effects of earthquakes on the deep repository for spent fuel in Sweden based on case studies and preliminary model results

    International Nuclear Information System (INIS)

    Baeckblom, Goeran; Munier, Raymond

    2002-06-01

    seismically rather silent and will remain so in the foreseeable future. Seismic hazard has been calculated for Sweden and it is concluded that Peak Ground Accelerations (PGA) greater than 2 m/s 2 is very unlikely the next coming 50-year period, in which the repository is planned to be constructed and operated. Damage due to shaking is very rare in underground facilities. Where such damage has occurred, the rock is either very poor or subject to very high stresses. None of these conditions will prevail in the Swedish repository. Most damage is also correlated to the presence of faults and the spent fuel will not be deposited in or close to important faults. Mining-induced earthquakes are known to cause damages in the mines. At the repository site it might be possible to experience local rock burst problems due to heterogeneous rock strengths and varying rock stresses. It is expected that these events, in case they appear, will take place when the tunnels are excavated rather than at the time of canister deposition. Earthquake impact during the post-closure phase: The present seismic activity in Sweden is expected to increase considerably in connection to the retreat of ice sheets in future glaciations. Peak ground accelerations may exceed 2 m/s 2 in association to large earthquakes. However, the effects of shaking, such as fallouts, cracking of lining are reduced since all tunnels will be backfilled by crushed rock and bentonite. The presence of the repository will not trigger earthquakes as the extraction ratio of the openings is very low compared to open stopes in a mine. There are also evidences for mines at great depth, that backfilling lower the mining-induced seismic activity compared to the situation when tunnels are not backfilled. The buffer and canister shake as a solid body without producing excess shear stresses or liquefaction of the buffer. Water-level changes will occur due to earthquakes but most of the changes are temporary and water-levels will return to

  3. Effects of earthquakes on the deep repository for spent fuel in Sweden based on case studies and preliminary model results

    Energy Technology Data Exchange (ETDEWEB)

    Baeckblom, Goeran [Conrox, Djursholm (Sweden); Munier, Raymond [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)

    2002-06-01

    seismically rather silent and will remain so in the foreseeable future. Seismic hazard has been calculated for Sweden and it is concluded that Peak Ground Accelerations (PGA) greater than 2 m/s{sup 2} is very unlikely the next coming 50-year period, in which the repository is planned to be constructed and operated. Damage due to shaking is very rare in underground facilities. Where such damage has occurred, the rock is either very poor or subject to very high stresses. None of these conditions will prevail in the Swedish repository. Most damage is also correlated to the presence of faults and the spent fuel will not be deposited in or close to important faults. Mining-induced earthquakes are known to cause damages in the mines. At the repository site it might be possible to experience local rock burst problems due to heterogeneous rock strengths and varying rock stresses. It is expected that these events, in case they appear, will take place when the tunnels are excavated rather than at the time of canister deposition. Earthquake impact during the post-closure phase: The present seismic activity in Sweden is expected to increase considerably in connection to the retreat of ice sheets in future glaciations. Peak ground accelerations may exceed 2 m/s{sup 2} in association to large earthquakes. However, the effects of shaking, such as fallouts, cracking of lining are reduced since all tunnels will be backfilled by crushed rock and bentonite. The presence of the repository will not trigger earthquakes as the extraction ratio of the openings is very low compared to open stopes in a mine. There are also evidences for mines at great depth, that backfilling lower the mining-induced seismic activity compared to the situation when tunnels are not backfilled. The buffer and canister shake as a solid body without producing excess shear stresses or liquefaction of the buffer. Water-level changes will occur due to earthquakes but most of the changes are temporary and water-levels will

  4. New Criteria to Assess Seismic and Rock Burst Hazard in Coal Mines / Nowe Kryteria Dla Oceny Zagrożenia Sejsmicznego I Tąpaniami W Kopalniach Węgla Kamiennego

    Science.gov (United States)

    Mutke, Grzegorz; Dubiński, Józef; Lurka, Adam

    2015-09-01

    The paper presents new criteria of seismic and rock burst hazard assessment in Polish hard coal mines where longwall mining system is common practice. The presented criteria are based on the results of continuous recording of seismic events and analysis of selected seismological parameters: spatial location of seismic event in relation to mining workings, seismic energy, seismic energy release per unit coal face advance, b-value of Gutenberg-Richter law, seismic energy index EI, seismic moment M0, weighted value of peak particle velocity PPVW. These parameters are determined in a moving daily time windows or time windows with fixed number of seismic tremors. Time changes of these parameters are then compared with mean value estimated in the analyzed area. This is the basis to indicate the zones of high seismic and rock burst hazard in specific moment in time during mining process. Additionally, the zones of high seismic and rock burst hazard are determined by utilization of passive seismic tomography method. All the calculated seismic parameters in moving time windows are used to quantify seismic and rock burst hazard by four level scales. In practice, assessment of seismic and rock burst hazard is used to make daily decision about using rock burst prevention activities and correction of further exploitation of monitored coal panel. Zagrożenie sejsmiczne i związane z nim genetycznie zagrożenie tąpnięciem w dalszym ciągu należą do najgroźniejszych zagrożeń naturalnych występujących w polskich kopalniach węgla kamiennego. W ostatnich latach w kopalniach Górnośląskiego Zagłębia Węglowego (GZW) rocznie rejestrowano 1000÷1500 wstrząsów o energii sejsmicznej Es ≥ 1·105J (magnituda lokalna ML ≥ 1.7), a najsilniejsze z nich osiągały energię Es = 4 ·109J (ML = 4.1). W latach 1991-2010 odnotowano w GZW 101 tąpnięć, z których około 66% miało miejsce w wyrobiskach chodnikowych, powodując ich uszkodzenia lub całkowite zniszczenie, a w