Current status of thin seam longwall mining in the US

Energy Technology Data Exchange (ETDEWEB)

Peng, S.S. [West Virginia Univ., Morgantown, WV (United States); Orndorff, A.

1996-12-31

Thin seams in this paper refers to those seams the economic mining height of which is below 50-55 in. that are traditionally considered to be the proprietary of plowing and present a whole net set of problems for longwall mining. In thin seams it is difficult to design and manufacture an efficient high capacity cutting machine for maintenance and production operations. Thin seam mining by longwall plowing began in the late fifties in southern West Virginia, and continues to the present time. In the seventies when longwall mining began to take off a large percentage of U.S. longwalls were operating in the thin seams. Tables 1 and 2 show the historical trends of cutting machines used for seams less than 55 in and 50 in, respectively. In addition to the plow system, the single-ended fixed drum and single-ended ranging drum shearers were introduced in the mid and late seventies and operated continuously until 2-4 years ago. The double-ended ranging drum shearers have also been employed for thin seam longwall mining during this period including several in-web (or off-pan) shearers between late seventies and early eighties. In this paper three thin-seam longwalls in three states employing the latest thin-seam longwall technology will be reviewed. However only two of them are still in operation while the third one ceased operation recently.

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

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.

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.

Squeezing the middleman: ending underhanded dealing in the pharmacy benefit management industry through regulation.

Science.gov (United States)

Meador, Mark

2011-01-01

Pharmacy benefit management (PBM) companies are the middlemen of the pharmaceutical industry, designing plans for sponsors and insurers and pushing the products of manufacturers. Their unique position can often create conflicts of interest, which has been the basis of much litigation. This article reviews the structure of the PBM industry and analyzes concerns arising from its handling of prescription drug pricing, manufacturer rebates and discounts, and mail order pharmacies. After surveying several legislative proposals, it concludes with a comprehensive outline for legislation to eliminate underhanded dealing in the industry and lower the cost of prescription drugs.

Modeling agricultural impacts of longwall mine subsidence: A GIS approach

International Nuclear Information System (INIS)

Darmody, R.G.; Vance, S.L.

1994-01-01

Illinois is both a major agricultural State and one of the leading coal-producing States. The future of coal mining in Illinois is longwall mining. One of the advantages of longwall mining, and the most noticeable consequence, is immediate subsidence. Mitigation of subsidence effects is the responsibility of the coal company. Research has shown that mitigation is usually effective, but may be difficult in many cases. Minimizing subsidence impact by avoiding sensitive soils in the mine plan is a possibility that should be considered. Predicting agricultural impacts of subsidence would give mine designers and regulating agencies an additional tool to use when evaluating mine plans. This paper reports on the development and an application of a predictive model of agricultural soil subsidence sensitivity (SSS). The SSS model involves integration of selected soil properties in a GIS (geographical information system) to assign a subsidence sensitivity class to a given area. Predicted crop yield losses at a proposed longwall mine in southern Illinois, using corn (Zea mays L.) as a reference, were 6.8% for the longwall panel area but ranged from 4.1% to 9.5% for the individual panels. The model also predicted that mitigation of the affected areas would reduce yield losses to 1.2% for the longwall area and to 0.5% to 1.7% for the individual panels

The organization of professional predictions on the development of automation for stope equipment

Energy Technology Data Exchange (ETDEWEB)

Kanygin, U.M.; Markashov, V.E.; Pashchevskii, U.G.

1980-01-01

The problems of organizing and conducting experimental predictions on the development of automation for stope equipment are examined. Professional evaluations are developed, and the order for processing the results is given, together with a calculation program for use with the ES-1020 computer. Several results from predictive studies of the development of automation for use with stope equipment are given.

Analysis of factors affecting the effect of stope leaching

International Nuclear Information System (INIS)

Xie Wangnan; Dong Chunming

2014-01-01

The industrial test and industrial trial production of stope leaching were carried out at Taoshan orefield of Dabu deposit. The results of test and trial production showed obvious differences in leaching rate and leaching time. Compared with industrial trial production of stope leaching, the leaching rate of industrial test was higher, and leaching time was shorter. It was considered that the blasting method and liquid arrangement were the main factors affecting the leaching rate and leaching time according to analysis. So we put forward the following suggestions: the technique of deep hole slicing tight-face blasting was used to reduce the yield of lump ores, the effective liquid arrangement methods were adopted to make the lixiviant infiltrating throughout whole ore heap, and bacterial leaching was introduced. (authors)

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.

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.

Realistic dynamic stope support testing

CSIR Research Space (South Africa)

Ortlepp, WD

2000-08-01

Full Text Available -August 1999. Construction of the steel superstructure commenced early in November 1999 and was completed within two weeks. Progress in commissioning the portal crane and the main compressed air hoist was hampered by small design faults and lack...’ for innovative developments. In particular, techniques for preventing collapses between support units and over the work area between the front line of support and the stope face can be explored. There can be little doubt that the facility could also serve a...

Application of Three Existing Stope Boundary Optimisation Methods in an Operating Underground Mine

Science.gov (United States)

Erdogan, Gamze; Yavuz, Mahmut

2017-12-01

The underground mine planning and design optimisation process have received little attention because of complexity and variability of problems in underground mines. Although a number of optimisation studies and software tools are available and some of them, in special, have been implemented effectively to determine the ultimate-pit limits in an open pit mine, there is still a lack of studies for optimisation of ultimate stope boundaries in underground mines. The proposed approaches for this purpose aim at maximizing the economic profit by selecting the best possible layout under operational, technical and physical constraints. In this paper, the existing three heuristic techniques including Floating Stope Algorithm, Maximum Value Algorithm and Mineable Shape Optimiser (MSO) are examined for optimisation of stope layout in a case study. Each technique is assessed in terms of applicability, algorithm capabilities and limitations considering the underground mine planning challenges. Finally, the results are evaluated and compared.

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

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...

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 ...

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.

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.

Remote Sensing Extraction of Stopes and Tailings Ponds in AN Ultra-Low Iron Mining Area

Science.gov (United States)

Ma, B.; Chen, Y.; Li, X.; Wu, L.

2018-04-01

With the development of economy, global demand for steel has accelerated since 2000, and thus mining activities of iron ore have become intensive accordingly. An ultra-low-grade iron has been extracted by open-pit mining and processed massively since 2001 in Kuancheng County, Hebei Province. There are large-scale stopes and tailings ponds in this area. It is important to extract their spatial distribution information for environmental protection and disaster prevention. A remote sensing method of extracting stopes and tailings ponds is studied based on spectral characteristics by use of Landsat 8 OLI imagery and ground spectral data. The overall accuracy of extraction is 95.06 %. In addition, tailings ponds are distinguished from stopes based on thermal characteristics by use of temperature image. The results could provide decision support for environmental protection, disaster prevention, and ecological restoration in the ultra-low-grade iron ore mining area.

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

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.

A device for preventing a stope from caving in

Energy Technology Data Exchange (ETDEWEB)

Novikov, V Ia; Pototskaia, I I; Semenov, Yu A; I, Tsoi L

1980-10-31

The goal of the invention is to increase the operational effectiveness of the device by fortifying the roof between the roof timber and the stope and to simplify the design. This is achieved by an arrangement whereby the roof timber is built with a mobile section that has a lever mounted to it with an axle.

Experience of attaining high labor productivity in a stoping face using mechanized complex 110PK-70

Energy Technology Data Exchange (ETDEWEB)

Reshetnikov, M N

1982-01-01

In 1979 when the first 1 million T of coal was produced at the mine ''Zyryanovskaya'' high volumes of coal extraction were attained in individual months: in January 102,300 T, in July 122,200 T. In 1980, high results were also attained. In January 106,000 T were extracted and in November 108,500 T of coal. The brigade has accumulated experience for introducing scientific organization of labor and improving labor productivity. In 1977 labor productivity of the workers in the stoping face was 31.5 T per shift, in 1978 variable productivity was elevated to 48.2 T. In 1979 labor productivity reached 67.3 T per shift. The best results for productivity was reached in June 1979, 90 T at the outlet, in February 1980--81.1 T per shift. The success of the brigade is formed of many factors, technical, organizational, economic. The basis for high labor productivity of the workers is timely preparation of new longwalls, normal production conditions for fulfillment of plans and the adopted socialist commitments. An important factor in the work of the extraction brigade is the type and condition of mining equipment. The level of work organization as a whole depends on the brigade, directly on the miners and the section leaders themselves. High conscientiousness of all the brigade members also is important for improving labor productivity. The majority of workers in the brigade (about 70%) are members of the party. Mass technical creativity of all the brigade members is also a great reserve for improving labor efficiency. The brigade has 24 efficiency experts who annually introduce 20-30 suggestions each aimed at improving work efficiency.

Determination Of Optimal Stope Strike Length On Steep Orebodies Through Laser Scanning At Lubambe Copper Zambia

Directory of Open Access Journals (Sweden)

Kalume H

2017-08-01

Full Text Available Lubambe Copper Mine is located in Chililabombwe Zambia and is a joint copper mining venture with three partners that include African Rainbow Minerals 40 Vale 40 and the Government of Zambia 20. The current mining method utilises Longitudinal Room and Pillar Mining LRP on 70m long panels strike length. However these long panels have resulted in unprecedented levels of dilution mainly from the collapse of hanging wall laminated ore shale OS2 leading to reduced recoveries. Observations made underground show high variability in geological and geotechnical conditions of the rock mass with factors such as weathering on joints lamina spaced joints and stress changes induced by mining all contributing to weakening and early collapse of the hanging wall. Therefore a study was undertaken to establish the optimal stope strike length of steep ore bodies at Lubambe. The exercise involved the use of Faro Laser Scanner every four stope rings blasted with time when the scan was performed noted. The spatial coherence of lasers makes them ideal measuring tools in situations where measurements need to be taken in inaccessible areas. Recent advances in laser scanning coupled with the exponential increase in processing power have greatly improved the methods used to estimate stope tonnages extracted from massive inaccessible stopes. The collected data was then used to construct digital three dimensional models of the stope contents. Sections were cut every metre with deformations taken and analysed with respect to time. Deformation rates from the hanging wall was reducing from 0.14thr to 0.07thr between rings 1 to 8. This reduction was as a result of slot blasting that involved drilling and blasting a number of holes at the same time. Between rings 8 to 25 deformation was constant averaging 0.28thr and between rings 26 and 28 a sharp increase in deformation rate was experienced from as low as 0.16thr to 6.33thr. This sharp increase defines the optimal stope length

A device for automatically recording information on the reasons for idling of stopes

Energy Technology Data Exchange (ETDEWEB)

Dergachev, L G; Kuzoyatov, G I; Tereshchenko, V N

1979-01-01

One substantial reserve for raising production efficiency in the coal industry is reduction of nonproductive time costs. The state of the art of stoping work and design features of stoping equipment and devices for obtaining information do not presently enable complete automation of the process of obtaining data on the reasons for down times. Therefore, together with automatic data formation manual recording of information is required through remote control equipment to the controlling computer directly from the work place. The Donetsk department of the Giprougleavtomatizatsiy institute has developed the UKIP-1 device for automatic recording of information on the reasons for stope down times. The device is designed for use in an automatic process control system of coal mines. It provides coding of information and its conversion to a form suitable for transmission through remote control channels, further processing, and recording. The device enables recording of information on down times of eight objects of the stope. Up to eight down time reasons can be recorded for each object. The device has 2 contact outputs, on one of which is formed an informational sequential eight-bit code; on the other, 8 clock pulses. The device's code is generated automatically, after it is activated by a switch. The length of the code packet results from the maximum possible information transmission rate of the existing mine remote control systems, and equals 12+2 sec. The clock pulse length equals half the length of the information pulse. The device has been tested at coal mines, and recommended for industrial production. UKIP-1 devices are being used in a pilot model of an automatic production control system of the Sotsialisticheskiy Donbass Newspaper mine of the Donetskugol' production association.

Three-dimensional time-lapse velocity tomography of an underground longwall panel

Energy Technology Data Exchange (ETDEWEB)

Luxbacher, K.; Westman, E.; Swanson, P.; Karfakis, M. [Virginia Tech., Blacksburg, VA (United States). Dept. of Mining & Minerals Engineering

2008-06-15

Three-dimensional velocity tomograms were generated to image the stress redistribution around an underground coal longwall panel to produce a better understanding of the mechanisms that lead to ground failure, especially rockbursts. Mining-induced microseismic events provided passive sources for the three-dimensional velocity tomography. Surface-mounted geophones monitored microseismic activity for 18 days. Eighteen tomograms were generated and high-velocity regions correlated with high abutment stresses predicted by numerical modeling. Additionally, the high-velocity regions were observed to redistribute as the longwall face retreated, indicating that velocity tomography may be an appropriate technology for monitoring stress redistribution in underground mines.

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.

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.

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

CSIR Research Space (South Africa)

Pickering, RGB

1988-03-01

Full Text Available supplemented by studies of work carried out by others, both in South Africa and overseas. The document has been prepared as part of a process of critically reviewing what progress has been made in solving the stoping problem and forms the basis for determining...

Study of behaviour of workings in longwall panel based on field instrumentation

Energy Technology Data Exchange (ETDEWEB)

V.R. Sastry; Roshan Nair [National Institute of Technology Karnataka, Mangalore (India). Department of Mining Engineering

2009-07-01

The paper presents field monitoring study of two adjacent longwall panels based on stress measurements in longwall block and barrier, load transferred on to the gate roads and convergence measurements in the gate roads during face retreat in the panels. Results indicated that the section of barrier lying in the goaf experienced higher abutment stress when compared with the section lying ahead of face. There was a transfer of load in gate roads ahead of face after the occurrence of roof fall in goaf. Maximum cumulative convergence of more than 8 mm was observed in the gate roads during weightings.

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)

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

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.

Dimensionless model to determine spontaneous combustion danger zone in the longwall gob

Institute of Scientific and Technical Information of China (English)

ZHANG Xin-hai; DENG Jun; WEN Hu

2011-01-01

According to spontaneous combustion propensity,the longwall gob is divided into three zones,including heat dissipation zone,self-heating zone and the choking zone.Only in the self-heating zone can temperature of coal rise due to oxidation.Studying the distribution of the “Three Zones” in gob is important for predicting and preventing spontaneous combustion in coalmine.In normal mining operations,temperature of coal is roughly constant.The process of mass transfer in the gob is considered to be steady.Based on mass conservation,gas species conservation,darcy' s law,Ficks law of diffusion and coal oxidation 1-grade reaction rule,governing equation for air leakage intensity and species concentration are deduced.With critical value of coal spontaneous combustion and the size of longwall workface as basic dimension,a dimensionless steady coupled model of air flow diffusion and chemical reaction in loose coal of Fully Mechanized Top-Coal Caving Mining Workface (FMTCCMW) is setup.By solving the model numerically,regulation of three zones' distribution and spontaneous combustion in the gob can be obtained.The results can be easily popularized to prediction of spontaneous combustion in other coalmines' longwall gob.

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

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.

New technology for real-time in-stope safety management

CSIR Research Space (South Africa)

Vogt, D

2009-09-01

Full Text Available with a clear idea of which portions of the hangingwall are safe, and which present risk. On the health side, if a network such as AziSA is deployed in the stope, it becomes much easier to monitor the condition of individual miners. The work strain... provide a safe environment in terms of rockfalls. Thermal imaging complements and enhances the current practices by allowing the miner to quickly scan a large area; his attention is being draw to potentially dangers hanging, with the benefit...

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 .7 m; and faults in the stope face with throws up to 2.5 m and rolls where the slope angle changes by up to 20o. The performance targets set for the system are a reduction in stope accidents of at least 50 % compared to the industry average, greater... than 15 m face advance per month, dilution and gold losses reduced by 15 % compared to adjacent stoping, consistent provision of recommended environmental conditions and finally cost effectiveness. The main areas of concern with current mining...

Response of surface springs to longwall coal mining Wasatch Plateau, Utah

International Nuclear Information System (INIS)

Kadnuck, L.L.M.

1994-01-01

High-extraction longwall coal mining creates zones in the overburden where strata bend, fracture, or cave into the mine void. These physical alterations to the overburden stratigraphy have associated effects on the hydrologic regime. The US Bureau of Mines (SBM) studied impacts to the local hydrologic system caused by longwall mining in the Wasatch Plateau, Utah. Surface springs in the vicinity of two coal mines were evaluated for alterations in flow characteristics as mining progressed. Fourteen springs located above the mines were included in the study. Eight of the springs were located over longwall panels, four were located over barrier pillars and mains, and two ere located outside the area disturbed by mining. Flow hydrographs for each spring were compared to climatic data and time of undermining to assess if mining in the vicinity had influenced flow. Heights of fracturing and caving in the overburden resulting from seam extraction were calculated using common subsidence formulas, and used in conjunction with elevations of springs to assess if fracturing influenced the water-bearing zones studied. One spring over a panel exhibited a departure from a normally-shaped hydrograph after being undermined. Springs located over other mine structures, or outside the mine area did not show discernible effects from mining. The limited response of the springs was attributed to site-specific conditions that buffered mining impacts including the elevation of the springs above the mine level, and presence of massive sandstones and swelling clays in the overburden materials

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

Influence of hole depth on output when excavating veins by small cuts to the course with the use of monorail stope equipment complexes

International Nuclear Information System (INIS)

Galchenko, Y.P.; Dadakuziev, B.M.; Saifutdinov, Y.N.

1986-01-01

A new comprehensive mechanization technology is discussed that uses monorail equipment installed along the course of the ore body. Trials of this machinery confirmed its efficiency, and a government commission has recommended the new technology for broad introduction in mines. The stope equipment complex with monorail advance has been recommended for mass production. It was noted that methods for determining the efficient parameters of the stope must be developed, especially a technique for estimating the breadth of the excavation cut as the principal indicator determining the cost-effectiveness and quality of stope excavation of veins worked to the course. An expression is presented that makes it possible to estimate the upper limit of the variation of hole depth that provides for the maximum excavation of the pay reserves

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)

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.

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.

Open-air sprays for capturing and controlling airborne float coal dust on longwall faces

Science.gov (United States)

Beck, T.W.; Seaman, C.E.; Shahan, M.R.; Mischler, S.E.

2018-01-01

Float dust deposits in coal mine return airways pose a risk in the event of a methane ignition. Controlling airborne dust prior to deposition in the return would make current rock dusting practices more effective and reduce the risk of coal-dust-fueled explosions. The goal of this U.S. National Institute for Occupational Safety and Health study is to determine the potential of open-air water sprays to reduce concentrations of airborne float coal dust, smaller than 75 µm in diameter, in longwall face airstreams. This study evaluated unconfined water sprays in a featureless tunnel ventilated at a typical longwall face velocity of 3.6 m/s (700 fpm). Experiments were conducted for two nozzle orientations and two water pressures for hollow cone, full cone, flat fan, air atomizing and hydraulic atomizing spray nozzles. Gravimetric samples show that airborne float dust removal efficiencies averaged 19.6 percent for all sprays under all conditions. The results indicate that the preferred spray nozzle should be operated at high fluid pressures to produce smaller droplets and move more air. These findings agree with past respirable dust control research, providing guidance on spray selection and spray array design in ongoing efforts to control airborne float dust over the entire longwall ventilated opening. PMID:29348700

Open-air sprays for capturing and controlling airborne float coal dust on longwall faces.

Science.gov (United States)

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

2018-01-01

Float dust deposits in coal mine return airways pose a risk in the event of a methane ignition. Controlling airborne dust prior to deposition in the return would make current rock dusting practices more effective and reduce the risk of coal-dust-fueled explosions. The goal of this U.S. National Institute for Occupational Safety and Health study is to determine the potential of open-air water sprays to reduce concentrations of airborne float coal dust, smaller than 75 µm in diameter, in longwall face airstreams. This study evaluated unconfined water sprays in a featureless tunnel ventilated at a typical longwall face velocity of 3.6 m/s (700 fpm). Experiments were conducted for two nozzle orientations and two water pressures for hollow cone, full cone, flat fan, air atomizing and hydraulic atomizing spray nozzles. Gravimetric samples show that airborne float dust removal efficiencies averaged 19.6 percent for all sprays under all conditions. The results indicate that the preferred spray nozzle should be operated at high fluid pressures to produce smaller droplets and move more air. These findings agree with past respirable dust control research, providing guidance on spray selection and spray array design in ongoing efforts to control airborne float dust over the entire longwall ventilated opening.

Improvements in longwall downtime analysis and fault identification

Energy Technology Data Exchange (ETDEWEB)

Daniel Bongers [CRCMining (Australia)

2006-12-15

In this project we have developed a computer program for recording detailed information relating to face equipment downtime in longwall mining operations. This software is intended to replace the current manual recording of delay information, which has been proven to be inaccurate. The software developed is intended to be operated from the maingate computer. Users are provided with a simple user interface requesting that nature of each delay in production, which is time-stamped in alignment with the SCADA system, removing the need for operators to estimate the start time and duration of each delay. Each instance of non-production is recorded to a database, which may be accessed by surface computers, removing the need for transcribing of the deputy's report into the delay database. An additional suggestive element has been developed, based on sophisticated fault detection technology, which reduces the data input required by operators, and provides a basis for the implementation of real-time fault detection. Both the basic recording software and the suggestive element offer improvements in efficiency and accuracy to longwall operations. More accurate data allows improved maintenance planning and improved measures of operational KPIs. The suggestive element offers the potential for rapid fault diagnosis, and potentially delay forecasting, which may be used to reduce lost time associated with machine downtime.

Selection of methods and parameters for forced weakening of roofing in stoping faces

Energy Technology Data Exchange (ETDEWEB)

Bekbulatov, A K

1982-01-01

The use of the method of advanced shooting on mines of different basins of the country indicated the need to generalize results of work for forced weakening of the roofing on mines in the sector in order to create ''Instructions For Selecting the Methods and Parameters of Forced Weakening of Roofing in the Stoping Faces'' with the participation of the basin scientific research institutes under the leadership of the VNIMI. The main method of weakening which has been introduced in the Karaganda basin is frontal shooting with the use of torpedo-charges. Shooting of the roofing in order reduce the intensity of the primary settling of the main roofing is done in parallel and perpendicular plans. With the parallel plan, the wells are drilled out from the adjoining roadways parallel to the stoping face, and with perpendicular plan, from the assembly chamber perpendicular to the stoping face. In order to reduce the intensity of secondary settling of the main roofing, the parallel or parallel-inclined method is used in designing of the torpedo-charge and the torpedo-head. It is reported that the torpedo-charge is a set of individual torpedos made of polyethylene pipes of length 1500 mm connected to each other with the help of couplings and splints. The torpedo-head consists of a polyethylene pipe of length 700 mm with wall thickness 15-17 mm filled with bulk explosives. Within the torpedo there are 2 explosive charges with electric-detonators for instantaneous action. The main cables of the explosive circuit are connected to the electric detonators and are passed through the packing pipe. In the improved design of the torpedo-head and the torpedo-charge, there are no metal parts. This excludes blow-out of particles of incandescent metal during the explosion and increases the level of work safety. The torpedo-charge is installed manually or mechanically with the help of a metal guide (rammer) which is removed from the well after it delivers the torpedo-charge.

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 Rockbursts pose a significant risk to workers in deep gold and platinum mines in South Africa. In-stope support systems are one of the measures used to mitigate the risk. Over the last two decades several new technologies have been introduced...

Active methods of preventing bumps in situations where the longwall face advances to and crosses a roadway in thick coal beds

Energy Technology Data Exchange (ETDEWEB)

Loboda, C

1978-01-01

The method was analyzed in the Wujek coal mine, where the coal bed is located at 600 m and was 5.3 m to 5.7 m thick. The following situation is described: A longwall face had to pass through a ventilation tunnel. To reduce the inner stress of the coal mass above and below the ventilation tunnel infusion was used. Water was forced into the walls of the tunnel. The tunnel section was 200 m long, 28 holes were drilled, each 40 m deep, diameter of the bore 42 to 45 mm, water pressure 300 at. To prevent bumps the orientation of the longwall face, which had been parallel to the ventilation tunnel, was changed so that it was at the angle of 15 degrees to the ventilation tunnel. Experience showed that the most dangerous situation in the tunnel arises when the distance between a longwall face and a roadway is reduced to 45 m. At that moment pressure on the road support system is the greatest. The danger of bumps at a longwall face is the greatest when it is 25 m away from a roadway.

Analysis of gob gas venthole production performances for strata gas control in longwall mining.

Science.gov (United States)

Karacan, C Özgen

2015-10-01

Longwall mining of coal seams affects a large area of overburden by deforming it and creating stress-relief fractures, as well as bedding plane separations, as the mining face progresses. Stress-relief fractures and bedding plane separations are recognized as major pathways for gas migration from gas-bearing strata into sealed and active areas of the mines. In order for strata gas not to enter and inundate the ventilation system of a mine, gob gas ventholes (GGVs) can be used as a methane control measure. The aim of this paper is to analyze production performances of GGVs drilled over a longwall panel. These boreholes were drilled to control methane emissions from the Pratt group of coals due to stress-relief fracturing and bedding plane separations into a longwall mine operating in the Mary Lee/Blue Creek coal seam of the Upper Pottsville Formation in the Black Warrior Basin, Alabama. During the course of the study, Pratt coal's reservoir properties were integrated with production data of the GGVs. These data were analyzed by using material balance techniques to estimate radius of influence of GGVs, gas-in-place and coal pressures, as well as their variations during mining. The results show that the GGVs drilled to extract gas from the stress-relief zone of the Pratt coal interval is highly effective in removing gas from the Upper Pottsville Formation. The radii of influence of the GGVs were in the order of 330-380 m, exceeding the widths of the panels, due to bedding plane separations and stress relieved by fracturing. Material balance analyses indicated that the initial pressure of the Pratt coals, which was around 648 KPa when longwall mining started, decreased to approximately 150 KPa as the result of strata fracturing and production of released gas. Approximately 70% of the initial gas-in-place within the area of influence of the GGVs was captured during a period of one year.

Improving the efficiency of longwall face recoveries by managing the geotechnical threats

Energy Technology Data Exchange (ETDEWEB)

David Hill; Rob Thomas [Strata Engineering (Australia)

2006-12-15

The project objective was to develop credible industry guidelines for the specification of effective ground control strategies, so as to minimise the likely geotechnical threats relating to the safety, operational costs and production delays associated with the recovery and relocation of a longwall face. The project commenced with an industry survey of longwall relocation practice. The resulting database covers issues such as the geotechnical environment, support practices and ground control experiences, including any difficulties encountered. Fieldwork aimed at geotechnical characterisation covered a range of environments in NSW and Queensland, drawing also on existing data from a number of mines. Longwall take-off monitoring data was obtained from 24 face recoveries across all the major coalfields. The fieldwork identified a number of critical features of the geotechnical environment, support design and mining geometry that have a pronounced impact on ground control during take-off. A cantilever model of roof behaviour at the take-off point was developed and validated by the data collected. The roof cantilever acts to transfer load to the solid abutment, the primary support element. Four parameters were identified as the main geotechnical hazards, namely: low roof competency (ie weak roof); an adverse weighting environment; geological structure; and horizontal stress concentrations at the gate ends (generally the maingate). Four aspects of the geometry and process were seen to be particularly significant, in terms of their impact on roof stability and the success of the overall operation, namely: the ability to maintain powered support resistance during bolt-up and take-off; the direction in which the powered supports are removed; the impact of take-off chutes; and the speed of the powered support removal process.

Longwall face recovery operations at Mine 26 of the Old Ben Coal Company, Benton, Illinois, USA

Energy Technology Data Exchange (ETDEWEB)

Monks, W R; Hodgkinson, D; Ferris, W

1985-02-01

The paper describes a longwall face recovery (salvage) operation witnessed by National Coal Board Western Areas personnel at No. 26 Mine of the Old Ben Coal Company in Venton, Illinois. A brief review is made of the company and No. 26 Mine, and followed by a description of the longwall face salvage operations detailing the face equipment, preparation work, salvage equipment used, the method of operation and the results obtained. Particular reference is made to the successful use of Free Steered Vehicles (FSVs) for salvaging equipment and the use of roof bolts for the primary support of the face line. Finally, a number of conclusions are made which lead to firm recommendations for UK adoption.

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

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

The evolution of longwall face support in the Mines de Potasse d'Alsace

Energy Technology Data Exchange (ETDEWEB)

Deffontaine, P

1978-06-01

In the Alsace (France) potash mines, caved longwalls were supported up to 1949 by timber chocks and friction or hydraulic props. Powered advancing support by chock type supports appeared in 1950 when shearers were put into service. Discloses evolution, progress, and costing of advancing supports in 1978. (In French)

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.

Development of oxidation heat of the coal left in the mined-out area of a longwall face: Modelling using the fluent software

Directory of Open Access Journals (Sweden)

Taraba B.

2008-01-01

Full Text Available A commercial CFD software program, Fluent, was used to study oxidation processes in the longwall mined-out (gob area. A three-dimensional model of the gob area with an advancing coal face has been developed. For the model, typical oxidation behavior of a bituminous coal from the Ostrava-Karviná District was incorporated as resulted from laboratory investigations. The longwall gob area was designed on the basis of the actual longwall face district. Detailed measurements in the district then enabled re-verification of the model outputs with actual data in situ. The main attention was paid to modelling the effect of grain size of the coal left in the mined-out area on the oxidation heat and gases evolution. Numerical simulations confirmed the existence of an 'optimal' zone for intense development of the spontaneous heating process in the gob area.

Estimation of active rockburst prevention effectiveness during longwall mining under disadvantageous geological and mining conditions

Directory of Open Access Journals (Sweden)

Łukasz Wojtecki

2016-01-01

Full Text Available Underground longwall mining of coal seams in the Upper Silesian Coal Basin is currently being carried out under increasingly difficult geological and mining conditions. Mining depth, dislocations and mining remnants are the main factors responsible for the most significant rockburst hazard, which can be minimized via the use of active and passive rockburst prevention. Active rockburst prevention in longwalls is usually based on blasting, in order to either destress local stress concentrations in the rock mass or to fracture the thick layers of strong roof rocks to prevent or minimize the impact of high energy tremors on excavations. The accurate estimation of active rockburst prevention effectiveness is particularly important when mining under disadvantageous geological and mining conditions, which are associated with high levels of this hazard. The efficiency of blasting applied for this purpose is typically evaluated from the seismic effect, which is calculated based on seismic monitoring data and the weight of the charged explosive. This method, as used previously in the Czech Republic, was adopted in the present study to analyze conditions occurring in a Polish hard coal mine in the Upper Silesian Coal Basin. Parameters of long hole destress blastings in roof rocks (torpedo blastings from the face of the assigned longwall in coal seam no. 507 were correct a success according to the seismic effect method and corresponded to observations made in situ. The analytical method presented enables the rapid estimation of destress blasting effectiveness and could also be useful when determining appropriate active rockburst prevention.

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.

Electrostatic purification of uranium mine stope atmospheres

International Nuclear Information System (INIS)

Case, G.; Phyper, J.D.; Lowe, L.M.; Chambers, D.B.

1986-01-01

Electrostatic precipitators have been and are currently being used to reduce levels of radioactive aerosols in uranium mine stope atmospheres. Historically, while the electrostatic precipitators have been reported to be successful in reducing levels of radioactive aerosols many practical problems have been encountered with their use in the underground mine environment. Electrical short circuiting appears to have been the major problem with the use of precipitators in humid underground environments. On the basis of literature reviewed for this study it seems that the problems encountered in the past can be overcome. The most likely use of a precipitator in an underground uranium mine is to treat some or all of the air immediately upstream of a work station. The possible locations and uses of a precipitator would vary from work station to work station and from mine to mine. The desirability and cost of using elctrostatic precipitators to purify the air entering a work station are application specific. SENES Consultants therefore is not recommending for or against the use of electrostatic precipitators in underground uranium mines. The information provided in this report can be used however to assist in such determinations. 72 refs

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

An influence function method based subsidence prediction program for longwall mining operations in inclined coal seams

Energy Technology Data Exchange (ETDEWEB)

Yi Luo; Jian-wei Cheng [West Virginia University, Morgantown, WV (United States). Department of Mining Engineering

2009-09-15

The distribution of the final surface subsidence basin induced by longwall operations in inclined coal seam could be significantly different from that in flat coal seam and demands special prediction methods. Though many empirical prediction methods have been developed, these methods are inflexible for varying geological and mining conditions. An influence function method has been developed to take the advantage of its fundamentally sound nature and flexibility. In developing this method, significant modifications have been made to the original Knothe function to produce an asymmetrical influence function. The empirical equations for final subsidence parameters derived from US subsidence data and Chinese empirical values have been incorporated into the mathematical models to improve the prediction accuracy. A corresponding computer program is developed. A number of subsidence cases for longwall mining operations in coal seams with varying inclination angles have been used to demonstrate the applicability of the developed subsidence prediction model. 9 refs., 8 figs.

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)

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.

Discussion: some new findings from surface subsidence monitoring over longwall panels

International Nuclear Information System (INIS)

Luo, Y.; Peng, S.S.; Arioglu, E.

1992-01-01

The article consists of a discussion of the paper, 'some new findings from surface subsidence monitoring over longwall panels' and a reply by the paper's authors, Luo and Peng. The reviewer, Arioglu, regards the paper favourably but suggests that surface subsidence can be represented by an exponential expression, and that there is a regression equation linking possible subsidence, pillar loading and the height-to-width ratio of the pillars left. Luo and Peng reply with their reasons for preferring their original linear regression model to the non-linear models suggested by Arioglu. 4 figs

Conventional approaches for assessment of caving behaviour and support requirement with regard to strata control experiences in longwall workings

Directory of Open Access Journals (Sweden)

G.S.P. Singh

2015-06-01

Full Text Available Effective control of roof strata is very important for trouble free operation and regular face advance in mechanised longwall workings. It is now technically possible to exploit coal seams in difficult geo-mining conditions with the help of newer innovations in longwall face machineries. A reliable assessment of caving behaviour and support capacity requirement helps in selecting supports of adequate capacity and making operational preparedness for timely and confident solution of impending problems. This paper reviews the mechanism of roof caving and the conventional approaches of caving behaviour and support requirement in the context of major strata control experiences gained worldwide. The review shows that a number of approaches are being used for advance prediction of caving behaviour and support capacity requirement in a variety of geo-mining conditions. The theoretical explanation of the mechanism of roof caving and the design function of roof supports have been worked out through staged development of approaches, their evaluation followed by their gradual modification and enrichment of synthesized findings. This process is still continuing with consistently improved understanding through growing field experiences in the larger domain of geo-mining conditions and state-of-art strata analysis and monitoring techniques. These attempts have contributed significantly to improving the level of understanding and reducing the gap of uncertainty in planning and design of longwall operation in a given geo-mining condition.

On the penetrability of the floor rock in the stope in coal mining%采动影响下采场底板岩体渗透性研究

Institute of Scientific and Technical Information of China (English)

张风达; 高召宁; 孟祥瑞

2012-01-01

In this paper, we would like to present our research results on the penetrability of the floor rock in the stope in coal mining production. Taking the stope near an aquifer for an example, the paper puts its research focus on the stress redistribution after the coal is mined and penetrability of the stope has changed its regularity. It is from this research perspective that we have developed a stress-permeability interactive model and the equation of the permeability variation by using the fracture mechanics theory and elastic mechanics. In pro-ceeding with our research, we first of all took into full account the effect of crack dip on the permeability of fractured rock, which is likely to be responsible for the destruction of the dominant angle of the fracture by coal mining and by the criterion of compression-shear fracture according to the fracture mechanics theory based on the influence of seepage water pressure. Secondly, based on the dominance angle and the stress-permeability model for fractured rock mass, we have established a stress-permeability interactive model of the dominance angle of the floor fractured rock in the stope. The stress distribution of the stope has been worked out according to the fracture mechanics theory, though it can only be applied to the end of the stope. We have then worked out the equation of permeability zero position failure zone and the stress distribution around the stope through an improved calculation. And, finally, we have established the stress-permeability interactive model of dominance angle of floor rock in the plane stress state by integrating the redistribution of stresses, with the relation of the seepage coefficient ratio and its affecting factors further analyzed. The results show that the permeability of zero position with zone failure and gob increases by the coal mining. And, then, the permeability would be found increasing with the increase of pressure release. Thus, it can be seen that the stress

A Coal Burst Mitigation Strategy for Tailgate during Deep Mining of Inclined Longwall Top Coal Caving Panels at Huafeng Coal Mine

Directory of Open Access Journals (Sweden)

Guorui Feng

2018-01-01

Full Text Available A coal burst mitigation strategy for tailgate in mining of deep inclined longwall panels with top coal caving at Huafeng Coal Mine is presented in this paper. Field data showed that coal bursts, rib sloughing or slabbing, large convergence, and so forth frequently occurred within the tailgate entries during development and panel retreating employing standard longwall top coal caving (LTCC layout which resulted in fatal injuries and tremendous profit loss. The contributing factors leading to coal bursts were analyzed. Laboratory tests, in situ measurement, and field observation demonstrate that the intrinsic bursting proneness of the coal seam and immediate roof stratum, deep cover, overlying ultrathick (500–800 m conglomerate strata, faults, and, most importantly, improper panel layout led to coal bursts. By employing a new strategy, that is, longwall mining with split-level gateroads (LMSG, gateroads on either end of a LMSG panel are located at different levels within a coal seam, adjacent LMSG panels overlap end to end, and the tailgate of the adjacent new LMSG panel can be located below the headgate entry of the previous LMSG panel or may be offset horizontally with respect to it. Numerical modeling was carried out to investigate the stress distribution and yield zone development within surrounding rock mass which was validated by field investigation. The results indicate that standard LTCC system gave rise to high ground pressure around tailgate entries next to the gob, while LMSG tailgate entry below the gob edge was in a destressed environment. Therefore, coal bursts are significantly mitigated. Field practice of LMSG at Huafeng Coal Mine demonstrates how the new strategy effectively dealt with coal burst problems in mining of deep inclined longwall panels with a reduced incidence of ground control problems. The new strategy can potentially be applied in similar settings.

Risk Analysis and Prediction of Floor Failure Mechanisms at Longwall Face in Parvadeh-I Coal Mine using Rock Engineering System (RES)

Science.gov (United States)

Aghababaei, Sajjad; Saeedi, Gholamreza; Jalalifar, Hossein

2016-05-01

The floor failure at longwall face decreases productivity and safety, increases operation costs, and causes other serious problems. In Parvadeh-I coal mine, the timber is used to prevent the puncture of powered support base into the floor. In this paper, a rock engineering system (RES)-based model is presented to evaluate the risk of floor failure mechanisms at the longwall face of E 2 and W 1 panels. The presented model is used to determine the most probable floor failure mechanism, effective factors, damaged regions and remedial actions. From the analyzed results, it is found that soft floor failure is dominant in the floor failure mechanism at Parvadeh-I coal mine. The average of vulnerability index (VI) for soft, buckling and compressive floor failure mechanisms was estimated equal to 52, 43 and 30 for both panels, respectively. By determining the critical VI for soft floor failure mechanism equal to 54, the percentage of regions with VIs beyond the critical VI in E 2 and W 1 panels is equal to 65.5 and 30, respectively. The percentage of damaged regions showed that the excess amount of used timber to prevent the puncture of weak floor below the powered support base is equal to 4,180,739 kg. RES outputs and analyzed results showed that setting and yielding load of powered supports, length of face, existent water at face, geometry of powered supports, changing the cutting pattern at longwall face and limiting the panels to damaged regions with supercritical VIs could be considered to control the soft floor failure in this mine. The results of this research could be used as a useful tool to identify the damaged regions prior to mining operation at longwall panel for the same conditions.

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).

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 effects of longwall mining on the local ground water regime are determined through field monitoring and numerical modeling. Field displacement data were obtained from multiple-position borehole extensometer (MPBX's) and survey monuments, combined with hydraulic drawdown and recovery tests completed both pre- and post-mining. Despite the development of significant mining induced displacements, the resulting effect on long-term water budgets was surprisingly small. Coupled flow-deformation modeling of the site was able to adequately define the post-mining mechanical and hydraulic response, including resulting conductivity magnitudes and water budgets. 6 refs., 5 figs., 2 tabs

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.

Experimental use of road header (AM-50) as face cutting machine for extraction of coal in longwall panel

Energy Technology Data Exchange (ETDEWEB)

Passi, K.K.; Kumar, C.R.; Prasad, P. [DGMS, Dhanbad (India)

2001-07-01

The scope of this paper has been limited to the use of available machines and techniques for attaining higher and more efficient production in underground coal mines. Under certain conditions of strata and higher degree of gassiness, the longwall method with hydraulic sand stowing is the only appropriate method of work for extraction of thick seam. In Moonidih Jitpur Colliery of M/S IISCO, No. 14 seam, Degree III gassy seam, 9.07 m thick, is extracted in multilift system with hydraulic sand stowing. In general, the bottom lift is extracted by Single Ended Ranging Arm Shearer and the middle and top lift are extracted by conventional method. However, in one of the panels spare road header machine was used as face cutting machine in bottom lift, on an experimental basis. This paper presents a successful case study of extraction of bottom lift coal by the longwall method with hydraulic sand stowing using road header (AM 50) as the face cutting machines. 9 figs.

Field investigation into the influene of anhydrite packing on longwall gate road stability

Energy Technology Data Exchange (ETDEWEB)

Dudley, W R

1977-01-01

Strata movements around a number of longwall roadways at Easington Colliery (UK), together with pack load, convergence, and area losses were determined. The influence of relatively incompressible anhydrite packs on roadway stability was particularly studied. Closures between roadways using this type of pack were compared with those using dirt filled wood chocks. The effectiveness of a Webster packer in controlling roadway convergence was assessed at Horden Colliery. The physical properties of anhydrite/accelerator mixtures likely to influence their use as a roadside packing material was also investigated. (91 refs.)

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

OpenAIRE

Gold, Judy; Burke, Eva; Ciss?, 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 outrea...

Sequential Gaussian co-simulation of rate decline parameters of longwall gob gas ventholes

Science.gov (United States)

Karacan, C. Özgen; Olea, Ricardo A.

2013-01-01

Gob gas ventholes (GGVs) are used to control methane inflows into a longwall mining operation by capturing the gas within the overlying fractured strata before it enters the work environment. Using geostatistical co-simulation techniques, this paper maps the parameters of their rate decline behaviors across the study area, a longwall mine in the Northern Appalachian basin. Geostatistical gas-in-place (GIP) simulations were performed, using data from 64 exploration boreholes, and GIP data were mapped within the fractured zone of the study area. In addition, methane flowrates monitored from 10 GGVs were analyzed using decline curve analyses (DCA) techniques to determine parameters of decline rates. Surface elevation showed the most influence on methane production from GGVs and thus was used to investigate its relation with DCA parameters using correlation techniques on normal-scored data. Geostatistical analysis was pursued using sequential Gaussian co-simulation with surface elevation as the secondary variable and with DCA parameters as the primary variables. The primary DCA variables were effective percentage decline rate, rate at production start, rate at the beginning of forecast period, and production end duration. Co-simulation results were presented to visualize decline parameters at an area-wide scale. Wells located at lower elevations, i.e., at the bottom of valleys, tend to perform better in terms of their rate declines compared to those at higher elevations. These results were used to calculate drainage radii of GGVs using GIP realizations. The calculated drainage radii are close to ones predicted by pressure transient tests.

3-D numerical modelling of stresses around a longwall panel with top coal caving

Energy Technology Data Exchange (ETDEWEB)

Yasitli, N.E.; Unver, B. [University of Hacettepe, Ankara (Turkey). Dept. of Mining Engineering

2005-06-01

There is a considerable amount of lignite reserve in the form of thick seams in Turkey. It is rather complicated to predict the characteristics of strata response to mining operation in thick seams. However, a comprehensive evaluation of ground behaviour is a prerequisite for maintaining an efficient production, especially when top coal winning by means of caving behind the face is applied. A comprehensive modelling of deformations and induced stresses is vital for the selection of optimum production strategy. In this study, numerical modelling and analysis of a longwall panel at Omerler underground coalmine have been carried out by using the software called FLAC(3D) developed based on the finite difference technique. Firstly, a 3-D numerical model of the M3 panel has been prepared. Secondly, induced stresses formed around the longwall face have been determined as a function of face advance where the face was located at the bottom of thick coal-seam. Results obtained from modelling studies have revealed that the front abutment vertical stress was maximum at 7 metres in front of the face and magnitude of front abutment stress was found to increase up to a distance of 200 metres away from the face start line. As the face was further advanced after 200 m from the face start line, there was not any significant change in the characteristics of front abutment stresses. Results of numerical analysis of the panel were in good agreement with in situ observations.

Thin Spray-on Liner - a potential application. Demonstrated at a longwall installation on Dendrobium mine

Energy Technology Data Exchange (ETDEWEB)

Byrnes, Roger [BHP Billiton, NSW (Australia). Dendrobium Mine; Martin, Philip [BASF AG Australia (Australia). BASF-CC Australia Ltd' s

2008-08-21

The paper describes a potential application of a Thin Spray-on Liner, on a longwall installation in Australia. The BHPBilliton mine, Dendrobium, is a relatively new mine in the Southern New South Wales coalfields, near to Wollongong. Normal installation and start-up operations for a new longwall face is to completely rock bolt and mesh the face. The operations use plastic/glassfibre cutable rock bolts, with steel/plastic mesh to prevent spalling. The biggest problem on face start up is the sheets of steel or plastic mesh getting wrapped around the shearer disc, which requires time consuming additional work removing the mesh. BASF Construction Chemicals Australia Pty Ltd's Underground Construction group, (UGC), proposed the use of Masterseal 845A, a fast sprayable cementitious/polymer membrane material that could be trialed and used to replace the steel mesh, as a surface support in unison with the conventional cutable rock bolts. The application took 12 h spraying to cover the 240 m long face line which averaged about 3.3 m high. The product was sprayed between 3.5 m to 4 mm thick, and according to the mine operators was at least three times quicker than mesh installation, not withstanding the savings in transport of the awkward bundles of mesh. In conclusion the Thin Spray-on Liner (TSL) performed adequately and achieved it's objective in this installation at Dendrobium mine. (orig.)

Numerical modelling of surface subsidence arising from longwall mining of steeply inclined coal seams

Energy Technology Data Exchange (ETDEWEB)

Nejad, M.A.; Reddish, D.J. [University of Nottingham, Nottingham (United Kingdom). School of Chemical, Environmental and Mining Engineering

1998-12-31

The paper presents results from and the methodology of a numerical modelling investigation into the surface ground movements above longwall mining of inclined and steep seams with varying panel configurations. A modelling approach was developed using a finite difference numercial model Fast Lagrangian Analysis of Continua (FLAC). On the basis of this methodology, representative surface subsidence profiles were simulated and the results of simulations were validated against the UK data using the Subsidence Engineer`s Handbook (SEH) and influence function methods. Furthermore, the proposed methodology was applied to two UK case histories for validation purposes. 15 refs., 7 figs., 3 tabs.

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 to be bimodal. The source of the bimodality is not known, and could be an effect introduced by the instrumentation or an indication of a fundamental difference in the physical mechanism of failure. It is strongly suggested that further work be done... the discontinuous nature of the hangingwall into account, was developed. The model focuses on the stress changes caused by the passage of Rayleigh waves along a stope. The importance of maintaining horizontal compressive stress, to ensure hangingwall stability...

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

Energy Technology Data Exchange (ETDEWEB)

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

2002-12-01

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

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.

CFD modelling of sampling locations for early detection of spontaneous combustion in long-wall gob areas.

Science.gov (United States)

Yuan, Liming; Smith, Alex C

In this study, computational fluid dynamics (CFD) modeling was conducted to optimize gas sampling locations for the early detection of spontaneous heating in longwall gob areas. Initial simulations were carried out to predict carbon monoxide (CO) concentrations at various regulators in the gob using a bleeder ventilation system. Measured CO concentration values at these regulators were then used to calibrate the CFD model. The calibrated CFD model was used to simulate CO concentrations at eight sampling locations in the gob using a bleederless ventilation system to determine the optimal sampling locations for early detection of spontaneous combustion.

Large-Strain Monitoring Above a Longwall Coal Mine With GPS and Seismic Measurements

Science.gov (United States)

Swanson, P. L.; Andreatta, V.; Meertens, C. M.; Krahenbuhl, T.; Kenner, B.

2001-12-01

As part of an effort to evaluate continuous GPS measurements for use in mine safety studies, a joint GPS-seismic experiment was conducted at an underground longwall coal mine near Paonia, Colorado in June, 2001. Seismic and deformation signals were measured using prototype low-cost monitoring systems as a longwall panel was excavated 150 m beneath the site. Data from both seismic and GPS instruments were logged onto low-power PC-104 Linux computers which were networked using a wireless LAN. The seismic system under development at NIOSH/SRL is based on multiple distributed 8-channel 24-bit A/D converters. The GPS system uses a serial single-frequency (L1) receiver and UNAVCO's "Jstream" Java data logging software. For this experiment, a continuously operating dual-frequency GPS receiver was installed 2.4 km away to serve as a reference site. In addition to the continuously operating sites, 10 benchmarks were surveyed daily with short "rapid-static" occupations in order to provide greater spatial sampling. Two single-frequency sites were located 35 meters apart on a relatively steep north-facing slope. As mining progressed from the east, net displacements of 1.2 meters to the north and 1.65 meters of subsidence were observed over a period of 6 days. The east component exhibited up to 0.45 meters of eastward displacement (toward the excavation) followed by reverse movement to the west. This cycle, observed approximately two days earlier at the eastern L1 site, is consistent with a change in surface strain from tension to compression as the excavation front passed underneath. As this strain "wave" propagated across the field site, surface deformation underwent a cycle of tension crack nucleation, crack opening (up to 15 cm normal displacements), subsequent crack closure, and production of low-angle-thrust compressional deformation features. Analysis of seismic results, surface deformation, and additional survey results are presented.

Surrounding rock abutment pressure distribution and thickness effect of dynamic catastrophic in fully mechanized sublevel mining stope

Energy Technology Data Exchange (ETDEWEB)

Xie, G.; Yang, K.; Chang, J.; Wang, L. [Anhui University of Science and Technology, Huainan (China)

2006-12-15

Numerical simulation was carried out to analyse the distribution of surrounding rock stress with coal seams of different thickness (3.0, 5.4, 8.0, 12.0 m) based on engineering geology and exploitation technology of the 151(3) fully mechanized sublevel caving face in Xieqiao colliery. The research indicates that the variation of abutment pressure has obvious difference in coal seams of different thickness. The effect of abutment pressure distribution in seams of different thickness on coal-methane outbursts was analysed. With an increase in thickness of the caving seam, the research illustrates that the elastic energy resilience is reduced and the capability of resisting damage and deformation is strengthened in coal around the stope. The results show that fully mechanized sublevel caving slows down dynamic catastrophes. 7 refs., 4 figs.

Developments in mechanization of operations of comprehensively mechanized longwalls in the USSR and abroad. Sovershenstvovanie sredstv mekhanizatsii kontsevykh operatsii v kompleksno-mekhanizirovannykh lavakh v SSSR i za rubezhom

Energy Technology Data Exchange (ETDEWEB)

Bodrunov, L D

1985-01-01

This paper discusses construction and introduction of equipment for mining at junctions of longwalls and roadways. Design and operation of a Soviet made narrow web shearer loader with chainless advance, enabling coal extraction by side cutting without the provision of stables in seams 2-4.1 m thick and up to 30 degrees inclination are described along with two types (520 mm and 630 mm high) of narrow web shearer loaders for extracting 0.7-0.95 m and 0.8-1.2 m thick seams with inclinations up to 35 degrees. Three types of machines constructed to operate in thin seams are presented. They are designed to extract coal from seams: 0.6-1.3 m thick with shear strength of 2.5 kN/cm, 0.65-1.2 m thick with shear strength up to 3.0 kN/cm and seams 0.8-1.8 m thick also with 3.0 kN/sm shear strength. Stableless extraction is also possible due to developments which have taken place in face scraper conveyors with shortened driving heads. Some of the new conveyors can be used in normal complexes to extract flat and inclined seams 1-2.5 m thick, whilst others are used to extract flat and inclined thin seams (0.7-1.2 m). The use of two shearer loaders has resulted in reduction in stable size or stableless extraction. Mechanization of supports at junctions of longwalls and mine roadways by means of metal supporting beams in conjunction with hydraulic or friction props is described. Mechanization of similar operations in foreign mines is also described, e.g. stableless extraction in the UK, where up to 80% of coal is extracted by the longwall system and 20% by the pillar system using the two shearer loader method. Machines produced by Anderson Strathclyde, Mining Supplies, and British Jeffrey Diamond and props manufactured by Dowty and Gullick Dobson are described. FRG coal extraction is carried out chiefly (95%) from inclined seams more than 4 m thick, using a pillar mining system (25%), longwall system (58%) and combined (17%).

Relaxation and gas drainage boreholes for high performance longwall operations in low permeability coal seams

Energy Technology Data Exchange (ETDEWEB)

Imgrund, Thomas [DMT GmbH und Co. KG, Essen (Germany); Bauer, Frank [Hazemag und EPR GmbH, Duelmen (Germany). Mining

2013-06-15

With an increasing depth of cover, gas emission control and gas outbursts prevention has become an increasingly important issue in coal mining. Deep multi-seam mining often requires operation in an environment characterised by a high gas content and gas pressure. Control of gas related risks has to be realised during heading and close to the longwall by proper risk assessment and flexible drilling schemes. These cover exploration and relaxation drilling, in-seam drilling for pre-drainage and cross measure drilling for drainage of roof and the floor gas emissions. DMT provides comprehensive solutions based on a scientific background. These solutions are engineered considering their technical feasibility. Hazemag Mining offers a large number of complete machinery including tools systems for the implementation of those solutions. (orig.)

CTL Industries simplifies mining processes : fill containment system a simple solution for backfilling stopes

Energy Technology Data Exchange (ETDEWEB)

Larmour, A.

2010-12-01

Several large mining companies are interested in a patent-pending fill containment system designed to replace shotcrete fences after a stope has been filled. The existing process is extremely labour and material intensive. This article discussed how the new system has made work easier, safer and increased the bottom line. The article described the design and specifications of the shotcrete containment system. The advantages of the system include no wait time for customers for shotcrete teams to build fences, and it is a quick, easy process that takes about 3 hours to set up, inflate and fill. The article also outlined a shaft guide electronic profiling mechanism that had been developed to complement the shaft guide laminating device. The product electronically measures shaft guides in mine shafts to determine how much wear has occurred on the timber. Last, the article described a refuge station door sealant kit with a cabinet that contains items required to seal the refuge station door should an emergency occur. This quick and easy system replaces the previous method in which clay slugs are soaked in a five-gallon pail of water and applied by hand. 1 ref., 1 fig.

Energy budgets of mining-induced earthquakes and their interactions with nearby stopes

Science.gov (United States)

McGarr, A.

2000-01-01

In the early 1960's, N.G.W. Cook, using an underground network of geophones, demonstrated that most Witwatersrand tremors are closely associated with deep level gold mining operations. He also showed that the energy released by the closure of the tabular stopes at depths of the order of 2 km was more than sufficient to account for the mining-induced earthquakes. I report here updated versions of these two results based on more modern underground data acquired in the Witwatersrand gold fields. Firstly, an extensive suite of in situ stress data indicate that the ambient state of crustal stress here is close to the failure state in the absence of mining even though the tectonic setting is thoroughly stable. Mining initially stabilizes the rock mass by reducing the pore fluid pressure from its initial hydrostatic state to nearly zero. The extensive mine excavations, as Cook showed, concentrate the deviatoric stresses, in localized regions of the abutments, back into a failure state resulting in seismicity. Secondly, there appears to be two distinct types of mining-induced earthquakes: the first is strongly coupled to the mining and involves shear failure plus a coseismic volume reduction; the second type is not evidently coupled to any particular mine face, shows purely deviatoric failure, and is presumably caused by more regional changes in the state of stress due to mining. Thirdly, energy budgets for mining induced earthquakes of both types indicate that, of the available released energy, only a few per cent is radiated by the seismic waves with the majority being consumed in overcoming fault friction. Published by Elsevier Science Ltd.In the early 1960's, N.G.W. Cook, using an underground network of geophones, demonstrated that most Witwatersrand tremors are closely associated with deep level gold mining operations. He also showed that the energy released by the closure of the tabular stopes at depths of the order of 2 km was more than sufficient to account for the

Mechanised packing for longwall coal faces. Monolithic packing and powered supports for the packhole

Energy Technology Data Exchange (ETDEWEB)

Carr, F; Kitching, F

1978-11-01

If full advantage is to be taken of the great advances that have taken place in power loading and powered support at the coalface, other operations in that vicinity must be similarly mechanised and automated. The gateside packing is one of the most important of these ancillary operations on the longwall face, and in previous articles F. Carr and F. Kitching, National Coal Board Headquarters, Coalface Operations Mining Engineers have given a very comprehensive resume of the present situation. Subjects covered include the requirements of mechanised packing, the parameters involved, the various working arrangements, the different systems of gate-ends, the types of equipment that are being used, their characteristics, the spread of their application, and the results obtained from them. In this article the authors conclude their survey by dealing with dirt/cement and anhydrite packing, by taking a hard look at powered supports for the packhole, and by expressing their views on the way mechanised packing may be expected to develop in the future.

Development stage of computerization and automation of machines and equipment used at longwall faces in Polish mines. Sostoyanie rabot po ehlektronizatsii i avtomatizatsii mashin i oborudovaniya, ustanavlivaemogo v lave i primenyaemogo v Pol'skikh shakhtakh

Energy Technology Data Exchange (ETDEWEB)

Sobchik, Yu; Pan' kuv, A; Sikora, W [Gornopromyshlennoe Obedinenie po Avtomatizatsii EMAG, Katowice (Poland)

1988-01-01

Discusses development of control equipment and control systems for machines and equipment used in underground black coal mining in Poland. The following types of control systems are comparatively evaluated: control systems for powered supports used at longwall faces (remote control, control of groups of powered support units, control of individual support units), control systems for shearer loaders (control of shearer loader position at a working face, control of motor loading, motor heating, pressure in hydraulic systems, control of roller bearings etc.), control systems for coal plows (remote start-up of a coal plow and auxiliary equipment, communications between coal miners at a working face, control of motor loading, control of cutting head position, water spraying, etc.), sensors used in control systems and control equipment. Development trends of control systems for equipment used at longwall faces are discussed.

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

Control effect of fracture on hard coal cracking in a fully mechanized longwall top coal caving face

Energy Technology Data Exchange (ETDEWEB)

Jin-ping Wei; Zhong-hua Li; Pei-miao Sang; Shang-qiang Chen [Henan Polytechnic University, Jiaozuo (China). School of Energy Science and Engineering

2009-03-15

Through theoretical analysis, simulation test and practice, the law of a fracture's influence on hard top coal press cracking was studied. The study focused on the relation between fracture and coal strength, top coal caving ability and work face layout. Based on the investigation of the fracture system, the control of press cracking was achieved by matching working face to fracture orientation to improve top-coal caving ability and recovery. The matching principle was pointed out: the top-coal caving working face should be perpendicular to or obliquely cross the primary fracture at a large angle, and cross the secondary fracture at a small angle. The rational match can increase the recovery ratio of top-coal and avoid rib spalling. The application of control technology on hard top coal press cracking was introduced at the longwall top-coal caving face. 10 refs., 2 figs., 1 tab.

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.

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.

3D numerical modeling of longwall mining with top-coal caving

Energy Technology Data Exchange (ETDEWEB)

Yasitli, N.E.; Unver, B. [Hacettepe University, Ankara (Turkey). Dept. of Mining Engineering

2005-02-01

Top-coal caving 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 a significant amount of coal is lost in the goaf but the coal drawn by means of caving is 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 3D modeling of the top-coal-caving mechanism by using the finite difference code FLAC3{sup D} at the M3 longwall panel of the Omerler Underground Mine located at Tuncbilek (Turkey) are presented. According to the modeling results, maximum vertical abutment stresses were formed at a distance of 7m in front of the face. An analysis of the conditions of top coal has revealed that a 1.5 m thick layer of coal just above the shield supports is well fractured. However, a 3.5 m thick layer of coal above the fractured part is either not fractured or is 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 efficiency of operation, top coal should be as uniformly fractured 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 with the results of numerical modeling.

Maximal loads acting on legs of powered roof support unit in longwalls with bumping hazards

Institute of Scientific and Technical Information of China (English)

Stanislaw Szweda

2001-01-01

In the article the results of measurements of the resultant force in th e legs of a powered roof support unit, caused by a dynamic interaction of the ro ck mass, are discussed. The measurements have been taken in the longwalls mined with a roof fall, characterized by the highest degree of bumping hazard. It has been stated that the maximal force in the legs Fm, recorded during a dynam ic interaction of the rock mass, is proportional to the initial static force in the legs Fst,p. Th erefore a need for a careful selection of the initial load of the powered roof s upport, according to the local mining and geological conditions, results from su ch a statement. Setting the legs with the supporting load exceeding the indispen sable value for keeping the direct roof solids in balance, deteriorating the ope rational parameters of a longwall system also has a disadvantageous influence on the value of the force in the legs and the rate of its increase, caused by a dy namic interaction of the rock mass. A correct selection of the initial load caus es a decrease in the intensity of a dynamic interaction of the rock mass on powe red roof supports, which also has an advantageous influence on their life. 　　Simultaneously with the measurements of the resultant force in the legs, the vertical acceleration of the canopy was also recorded. It has enabled to prove that the exte rnal dynamic forces may act on the unit both from the roof as well as from the f loor. The changes of the force in the legs caused by dynamic phenomena intrinsic ally created in the roof and changes of the force in the legs caused by blasting explosives in the roof of the working, have been analyzed separately. It has been stated that an increase in the loads of legs, caused by intrinsi c phenomena is significantly higher than a force increase in the legs caused by blasting. It means that powered roof supports, to be operated in the workings, w here the bumping hazard occurs, will also transmit the loads

Economical Optimization of the Mechanized Longwall Faces with Top Coal Caving Mining, In Horizontal Slices

Science.gov (United States)

Onica, Ilie; Mihăilescu, Viorel; Andrioni, Felicia

2016-09-01

To increase the economic and technical performances of the Jiu Valley hard coal mines, the top coal caving, in horizontal slices, mining methods (Bourbaki methods) were introduced, adapted to the local geo-mining conditions. This mining was successfully experimented by using classical technology, using the individual supports and coal blasting. In the future, it is planned to adopt the mechanized technology, with frame supports and shearers. The mechanized longwall faces with top coal caving mining, in horizontal slices, of coal seam no. 3 could be efficient only if the sizes of the top coal height and the panel length determine a minimum cost of production. Therefore, the goal of this paper is the optimization of these parameters, from a technical and economic point of view, taking into account the general model of the cost function, at the panel level. For that, it was necessary to make a certain sequence of analysis involving: technological unit establishment, purpose function and optimizing model. Thus, there attaining to the mathematical model of the unit cost, after determination of all the individual calculation articles, regarding the preparatory workings, coal face equipments, materials, energy, workforce, etc. Because of the complexity of the obtained technical and economic model, to determine the optimum sizes of the panel length and top coal height, it was necessary to archive a sensitivity analysis of the unit cost function to the main parameters implied into this mathematical model.

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.

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

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

2014-02-01

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 choice

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

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

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.

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)

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

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

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

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

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

Tube bundle system studies at Signal Peak Energy Bull Mountains #1 Mine.

Science.gov (United States)

Zipf, R K; Ochsner, R; Krog, R; Marchewka, W; Valente, M; Jensen, R

2014-03-01

A tube bundle system (TBS) is a mechanical system for continuously drawing gas samples through tubes from multiple monitoring points located in an underground coal mine for analysis and display on the surface. The U.S. National Institute for Occupational Safety and Health (NIOSH), in collaboration with Signal Peak Energy (SPE), LLC, Bull Mountains No. 1 Mine, operated a TBS during mining of two bleederless, longwall panels. This paper describes the gas analysis data and its interpretation. As verified by the TBS, coal at the SPE mine tends to oxidize slowly. It was known that a reservoir of low-oxygen concentration atmosphere developed about 610 m (2,000 ft) behind the longwall face. A bleederless ventilation system facilitates formation of an inert atmosphere in this longwall gob and decreases the likelihood of spontaneous combustion. Connections of the mine atmosphere to the surface through subsidence cracks could allow airflow into the longwall gob, revive coal oxidation and increase spontaneous combustion risk. The atmospheric composition of the sealed areas was homogeneous, except in the immediate vicinity of suspected ingassing points. The TBS verified that gases within the partially sealed, bleederless longwall gob expanded into the longwall tailgate area when barometric pressure decreased. The concentration of carbon dioxide in the back return airflow at the longwall tailgate was observed to increase by a factor of three and possibly up to 10 times the typical background concentration of 0.5 to 1.0%, depending on the size of the longwall gob and the magnitude of barometric pressure decrease. TBS have the inherent disadvantage of slow response time due to travel time of the gas samples and sequential gas analyses. A TBS or similar continuous monitoring system could be beneficial in detecting and providing warning of potentially hazardous gas concentrations, if the slow response time of the system is always understood.

Underground coal mining technology - the future

Energy Technology Data Exchange (ETDEWEB)

Lama, R P [Kembla Coal and Coke Pty Limited, Wollongong, NSW (Australia)

1989-01-01

Discusses development of underground coal mining in Australia in the last four decades. The following aspects are reviewed: technology for underground mining (longwall mining, unidirectional cutting, bidirectional cutting, operation of more than one shearer on a working face, optimum dimensions of longwall blocks), longwall productivity (productivity increase will depend on increasing the availability factor of equipment, reducing failures due to human errors, organizational models, improving on-site decision making, improving monitoring, maintenance, planning and scheduling, concept of 'Transparent Mine'), roadway development systems (types of heading machines, standard systems for mine drivage and roof bolting and their productivity), size of coal mines, man and material transport systems (20,000-30,000 t/d from a single longwall face, mine shafts with a diameter 9-10 m), mine layout design (layout of longwall blocks, main intakes and returns situated in rock layers), mine environmental systems (ventilation systems, gas control), management, training and interpersonal relationships. Future coal mines will be developed with an integral capacity of 8-10 Mt/a from a single longwall operation with main development arteries placed in rocks. Development of gate roadways will require novel solutions with continuous cutting, loading and bolting. Information technology, with the concept of 'transparent mine', will form the backbone of decision making.

Development of a time-dependent energy model to calculate the mining-induced stress over gates and pillars

Directory of Open Access Journals (Sweden)

Mohammad Rezaei

2015-06-01

Full Text Available Generally, longwall mining-induced stress results from the stress relaxation due to destressed zone that occurs above the mined panel. Knowledge of induced stress is very important for accurate design of adjacent gateroads and intervening pillars which helps to raise the safety and productivity of longwall mining operations. This study presents a novel time-dependent analytical model for determination of the longwall mining-induced stress and investigates the coefficient of stress concentration over adjacent gates and pillars. The model is developed based on the strain energy balance in longwall mining incorporated to a rheological constitutive model of caved materials with time-varying parameters. The study site is the Tabas coal mine of Iran. In the proposed model, height of destressed zone above the mined panel, total longwall mining-induced stress, abutment angle, induced vertical stress, and coefficient of stress concentration over neighboring gates and intervening pillars are calculated. To evaluate the effect of proposed model parameters on the coefficient of stress concentration due to longwall mining, sensitivity analysis is performed based on the field data and experimental constants. Also, the results of the proposed model are compared with those of existing models. The comparative results confirm a good agreement between the proposed model and the in situ measurements. According to the obtained results, it is concluded that the proposed model can be successfully used to calculate the longwall mining-induced stress. Therefore, the optimum design of gate supports and pillar dimensions would be attainable which helps to increase the mining efficiency.

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.

Erupted frothy xenoliths may explain lack of country-rock fragments in plutons

Science.gov (United States)

Burchardt, Steffi; Troll, Valentin R.; Schmeling, Harro; Koyi, Hemin; Blythe, Lara

2016-01-01

Magmatic stoping is discussed to be a main mechanism of magma emplacement. As a consequence of stoping, abundant country-rock fragments should occur within, and at the bottom of, magma reservoirs as “xenolith graveyards”, or become assimilated. However, the common absence of sufficient amounts of both xenoliths and crustal contamination have led to intense controversy about the efficiency of stoping. Here, we present new evidence that may explain the absence of abundant country-rock fragments in plutons. We report on vesiculated crustal xenoliths in volcanic rocks that experienced devolatilisation during heating and partial melting when entrained in magma. We hypothesise that the consequential inflation and density decrease of the xenoliths allowed them to rise and become erupted instead of being preserved in the plutonic record. Our thermomechanical simulations of this process demonstrate that early-stage xenolith sinking can be followed by the rise of a heated, partially-molten xenolith towards the top of the reservoir. There, remnants may disintegrate and mix with resident magma or erupt. Shallow-crustal plutons emplaced into hydrous country rocks may therefore not necessarily contain evidence of the true amount of magmatic stoping during their emplacement. Further studies are needed to quantify the importance of frothy xenolith in removing stoped material. PMID:27804996

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.

Investigate the rock mechanics aspects of potholes in the platinum mines, their contribution to poor ground conditions, and if proactive identification is possible

CSIR Research Space (South Africa)

Urcan, H

2003-07-01

Full Text Available The main aim of this project was to define and quantify the effect of potholes on ground conditions in platinum stopes, and assess whether these changes could be used to predict the occurrence of potholes ahead of stope faces. In order to gain...

Optimization and application of blasting parameters based on the "pushing-wall" mechanism

Science.gov (United States)

Ren, Feng-yu; Sow, Thierno Amadou Mouctar; He, Rong-xing; Liu, Xin-rui

2012-10-01

The large structure parameter of a sublevel caving method was used in Beiminghe iron mine. The ores were generally lower than the medium hardness and easy to be drilled and blasted. However, the questions of boulder yield, "pushing-wall" accident rate, and brow damage rate were not effectively controlled in practical blasting. The model test of a similar material shows that the charge concentration of bottom blastholes in the sector is too high; the pushing wall is the fundamental reason for the poor blasting effect. One of the main methods to adjust the explosive distribution is to increase the length of charged blastholes. Therefore, the field tests with respect to increasing the length of uncharged blastholes were made in 12# stope of -95 subsection and 6# stope of Beiminghe iron mine. This paper took the test result of 12# stope as an example to analyze the impact of charge structure on blasting effect and design an appropriate blasting parameter that is to similar to No.12 stope.

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

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.

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)

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...

75 FR 81313 - Petitions for Modification of Existing Mandatory Safety Standards

Science.gov (United States)

2010-12-27

... every 7 days, due to adverse roof, rock falls, and floor heave conditions in the return entry in the C... continuing mining cycle; (2) the longwall development panels consist of a three-entry system with 275-foot... being developed at the mine as part of a continuing mining cycle; (2) the longwall development panels...

The forecasting method of rock-burst and the application based on overlying multi-strata spatial structure theory

Energy Technology Data Exchange (ETDEWEB)

Cun-Wen Wang; Fu-Xing Jiang; Qing-Guo Sun; Chun-Jiang Sun; Ming Zhang; Zhen-Wen Ji; Xiu-Feng Zhang [University of Science and Technology, Beijing, Beijing (China). Civil & Environmental Engineering School

2009-02-15

Based on the overlying multi-strata spatial structure theory and mechanical analysis, the paper discusses the relationship between 'S' shape spatial strata structure movement and mining stress distribution. Coal out-burst forecasting based on 'S' shape spatial strata structure movement was studied. Microseismic monitoring in Huafeng Coal Mine in Shandong Province showed that coal out-burst will ocur when the advancing distance of the longwall face is equal to one, two or three times the length of the longwall face respectively. During these periods, the mined areas approach to square shape while the 'S' shape spatial strata structure acts strongly. Based on this, the time and position of coal out-burst in No. 1410 longwall face of Huafeng Coal Mine was predicted. By using large diameter and deep drill holes in the coal seam and deep drill holes with blasting in the roof at those danger areas, the No. 1410 longwall face safely advanced through those danger areas. During those periods the microseismic monitoring system detected very strong mine quakes. 15 refs., 1 fig., 2 tabs.

Method and apparatus for dismantling mechanical anchors

Energy Technology Data Exchange (ETDEWEB)

Dubovskiy, Yu P; Chendev, F S; Gritsayuk, B I; Gubin, N I; Osipov, S P

1982-01-01

This apparatus is designed to reduce the amount of labor required to dismantle mechanical anchors while at the same time lowering expenditures for lumber. Longwall beams and timber skips are used to support the cap and any fractured rock faces. The apparatus itself has grooves, vertical guides, and a drive system to position the longwall beams.

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

Problems occurred in prospecting and mining of a broken thick large uranium ore body and improvement scheme

International Nuclear Information System (INIS)

Hu Longfei; Fang Yang; Wang Yishun; Wang Long

2014-01-01

In prospecting and mining of a broken thick large uranium ore body, uncertain prospecting and shallow-hole shrinkage mining method resulted in large dilution rate and resource waste problems. Aimed at these problems, improvement schemes of enhancing the strength force of 'drilling prospecting instead of pit prospecting' and employing filling method stoping ore body were applied, and improvement result was analyzed. Experience was accumulated and evidence was provided for late prospecting and stoping work. (authors)

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

Underground bioleaching: extracting from low-grade ore

International Nuclear Information System (INIS)

McCready, R.G.L.

1986-01-01

In 1984, Denison Mines began a research and demonstration project on the engineering aspects of bacterial leaching of low-grade uranium ore at Elliot Lake. The leaching solution was acidic mine water enriched in bacterial nutrients and innoculated with Thiobacillus ferrooxidans. Leaching of one stope was found to be impeded by fungi of the genus penicillium. Although fungal growth on leaching stopes must be prevented, research is proceeding on the potential use of the fungi to concentrate uranium from bioleaching solutions

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

Maximal loads acting on legs of powered roof support unit in longwalls with bumping hazards

Institute of Scientific and Technical Information of China (English)

StanislawSzweda

2001-01-01

during blasting. The majority of recorded force changes in the legs has been caused by a dynamic interaction of the roof. They are characterized by a load increase coefficient Kd, satisfying the inequality i .06 < Kd = Fm/Fst.p < 1.24. A much smeller number of cases, when the external load acted on the bases, was recorded. Individual, recorded results of measurements indicate that changes of the force in the legs, caused by external loads of this type, run more intensively due to roof loads (1.08 < Kd< l. 80), particularly in these cases when the nearthe-roof layer of the seam Is under mining. A determination of more precise relations among the changes of forces in the legs, caused by a dynamic interaction of the floor and the bases and the mining and geological conditions requires a performance of additional underground tests. Keywords longwall, bumping hazard, powered roof support unit

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.

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.

Stope face support systems

CSIR Research Space (South Africa)

Daehnke, A

1998-12-01

Full Text Available The primary output of this report was the determination of geotechnical areas across the gold and platinum mines to form the basis for future understanding of the rock mass behaviour around reefs where the hanging wall and footwall rock types differ...

Shoulder and Scapular Kinematics during the Windmill Softball Pitch

OpenAIRE

Backus, Sherry I.; Kraszewski, Andrew; Kontaxis, Andreas; Gibbons, Mandi; Bido, Jennifer; Graziano, Jessica; Hafer, Jocelyn; Jones, Kristofer J.; Hillstrom, Howard; Fealy, Stephen

2013-01-01

Objectives: Pitch count has been studied extensively in the overhand throwing athlete. However, pitch count and fatigue have not been systematically evaluated in the female windmill (underhand) throwing athlete. Direct kinematic measurements of the glenohumeral and scapulo-thoracic joint have not to be correlated and determined. The purpose is to measure scapular kinematics for the high school female windmill softball pitcher and identify kinematic adaptions and changes in pitching performanc...

A new approach to predict underground gassiness for design of gas capture and ventilation systems

Energy Technology Data Exchange (ETDEWEB)

Lunarzewski, L.W.; Lunarzewski, A.L. [Lunagas Pty Limited, Junction (Australia); Pilcher, R.C. [Raven Ridge Resources, Grand Junction, CO (United States)

1995-12-31

The Floorgas and Roofgas simulation programs are used to identify strata relaxation zones and their boundaries, to assess active gas sources from coal seams and gas-bearing rocks and to determine relevant gassiness prediction coefficients for any local longwall. The paper shows that by use of the print-outs from the Floorgas and Roofgas programs the following benefits are achievable: (1) identification of the shear and gas discharge zone positions in the floor, strata relaxation angles and various gas discharge zone positions in the roof, which are both relevant to local geological and mining conditions; (2) optimisation of cross-measure drainage hole length, location, number and angle of inclination; and (3) calculation and definition of gas make prediction coefficients such as the release ratio from adjacent coal seams, specific gas emission during longwall extraction and the relationships between gas make, longwall width and coal production levels.

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

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.

Radiation, ventilation and dust studies at Agnew Lake mines

International Nuclear Information System (INIS)

Bigu, J.; Gangal, M.; Knight, G.; Regan, R.; Stefanich, W.

1980-08-01

Measurements of radon gas, radon and thoron decay products, ventilation, and aerosol (<= 0.13 μm) and respirable dust (<= 10 μm) concentrations were conducted at an underground uranium mine in the Agnew Lake, Ontario, area. Radon gas measurements were carried out with a radon gas continuous monitoring system, whereas the other variables were determined by grab-sampling techniques. Studies were conducted at three mine locations: a working stope, an exhaust area near the stope and a general intake area supplying fresh air to several stopes. Radiation and dust studies were carried out for different mining operations (mainly mucking and drilling) and environmental conditions. Underground barometric pressure did not seem to affect radon gas levels. No obvious effect on radiation and dust levels was readily observed nor could be correlated with underground meteorological data within the relatively narrow range the (meteorological) variables changed. Theoretical calculations for some radiation variables were done and compared with experimental values. Within the limitations of some of the calculations, overall fair agreement between experimental and theoretical data was found

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)

Bing-Neel Syndrome: Illustrative Cases and Comprehensive Review of the Literature

OpenAIRE

Varettoni, Marzia; Defrancesco, Irene; Diamanti, Luca; Marchioni, Enrico; Farina, Lisa Maria; Pichiecchio, Anna

2017-01-01

The Bing-Neel syndrome is a rare neurological complication of Waldenström’s Macroglobulinemia which results from a direct involvement of central nervous system by malignant lymphoplasmacytic cells. The clinical suspicion of Bing-Neel syndrome may be difficult because neurologic symptoms are heterogeneous, non specific and sometimes underhand. A definitive diagnosis of Bing-Neel syndrome can be confidently made using brain and spinal cord magnetic resonance imaging as well as histopathology an...

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...... 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....

Selected problems of coal mining mechanization in the coal industry of Poland

Energy Technology Data Exchange (ETDEWEB)

Antoniak, J; Sikora, W [Politechnika Slaska, Gliwice (Poland)

1987-01-01

Discusses conditions for underground coal mining in Poland, types of equipment for coal cutting, mine haulage and strata control and development trends of mining technologies. In 1985, black coal output was 191.6 Mt; 85.3% came from longwall faces mined by sets of mining equipment (coal cutters, chain conveyors and powered supports). The average coal output per longwall face was 881 t/d, output per face mined by sets for mining equipment was 1,134 t/d. In 1985, 653 shearer loaders and 77 coal plows were used in Polish coal mines. Number of shearer loaders is increasing. Shearer loaders with chainless haulage system were safest and most economic. The shearer loaders were equipped with the POLTRAK chainless haulage system developed in Poland. Research programs concentrate on development of new mining equipment for thin seam mining, steep seam mining, longwall mining with hydraulic stowing, efficient strata control by powered or shield supports under conditions of increased stresses or rock burst hazards. 4 refs.

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.

Improving the support characteristics of hydraulic fill

Energy Technology Data Exchange (ETDEWEB)

Corson, D. R.; Dorman, K. R.; Sprute, R. H.

1980-05-15

Extensive laboratory and field testing has defined the physical properties of hydraulic fill. Effect of void ratio on percolation rate has been quantified, and tests were developed to estimate waterflow through fill material in a given state underground. Beneficial effect on fill's support capability through addition of cement alone or in conjunction with vibratory compaction has been investigated. Two separate field studies in operating cut-and-fill mines measured vein-wall deformation and loads imposed on backfilled stopes. Technology has been developed that will effectively and efficiently dewater and densify ultra-fine-grained slurries typical of metal mine hydraulic backfill. At least two operators are using this electrokinetic technique to dewater slimes collected in underground sumps or impoundments. This technique opens up the possibility of using the total unclassified tailings product as a hydraulic backfill. Theoretical enhancement of ground support and rock-burst control through improved support capability will be tested in a full-scale mine stope installation. Both a horizontal layer and a vertical column of high modulus fill will be placed in an attempt to reduce stope wall closure, support more ground pressure, and lessen rock-burst occurrence.

Coal mining technologies possible for use in the Polish hard coal mining sector ensuring its sustainable development; Technologie eksploatacji wegla mozliwe do zastosowania w polskim gornictwie wegla kamiennego zapewniajace jego zrownowazony rozwoj

Energy Technology Data Exchange (ETDEWEB)

Dubinski, J. [Central Mining Institute, Katowice (Poland)

2004-07-01

The paper presents a prediction of the developments in hard coal mining technologies both in Poland and in the world. The longwall and the room-and-pillar systems will be realised. In Poland longwall equipment must be made more reliable and be better monitored, and more use made of roof bolting and means of controlling methane and rockbursts. Methods of underground gasification of coal seams need further development to realise the potential of this resource at reasonable production cost and with minimal environmental impact. 38 refs., 6 figs., 4 tabs.

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

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

Developments in the application of underground battery vehicles in the UK coal mining industry

Energy Technology Data Exchange (ETDEWEB)

Fortune, J A.B.; Crawshaw, S A.M. [Long-Airdox International Ltd. (United Kingdom)

1996-10-01

Trackless battery powered haulage vehicles have been in operation in British coal mines principally for longwall face transfer and personnel transportation. Changes within the industry have resulted in the introduction of room and pillar coal mining methods and the introduction of increasingly heavier longwall roof supports. This has resulted in the introduction of: battery powered coal haulage machines, which, without the need for trailing cables, increase productivity within room and pillar mining; and battery powered longwall shield haulers which are capable of carrying the heaviest shield supports currently being utilised within the British coal mining industry. The conventional machines have been adapted from an American design to meet the requirements of European legislation. This has seen the emphasis being placed upon the supplier with the European Machinery Directive being introduced, necessitating the assigning of a `CE` mark to each vehicle. Battery vehicle technology has advanced to meet the demands of the ever changing market and will no doubt be further adapted to meet the requirement of the British coal mining industry. 1 ref., 12 figs., 3 tabs.

Accuracy of forecast of mine tremors location

Energy Technology Data Exchange (ETDEWEB)

Jan Drzewieck [Central Mining Institute, Katowice (Poland)

2009-09-15

The Upper Silesian Coal Basin is one of the most active mining areas in the world in respect of seismicity. Underground mining in this area takes place in a special environment with a high degree of risk of unpredictable event occurrence. Especially dangerous are phenomena that occur during the extraction of deposits at great depths in the environment of compact rocks. Deep underground mining violates the balance of these rocks and induces dynamic phenomena at the longwall life (in terms of distance) referred to as mine tremors. The sources of these tremors are located in layers characterised by high strength, especially in thick sandstone strata occurring in the roof of the mined seam. In the paper a discussion is presented about the influence of mining intensity (longwall face speed) on the location of mine tremor sources, both in the direction of longwall life (in terms of distance) and towards the surface. The presented material has been prepared based on the results of tests and measurements carried out at the Central Mining Institute. 8 refs., 5 figs.

Development trends in mining technologies. [Poland

Energy Technology Data Exchange (ETDEWEB)

Sikora, W

1983-01-01

Research programs on underground black coal mining in Poland are discussed. It is assumed that no major technology changes will take place by the year 2000. Second generation of mining technologies will be used after the year 2000. The following technologies of the second generation are discussed: in-situ gasification, chemical coal disintegration, manless hydraulic mining with hydraulic transport. Research programs on technologies of the second generation should guarantee their commercial and economic use by the year 2000. The following targets for research programs aimed at increasing productivity, reducing mining cost, reducing labor and increasing safety in mining, covering the next 2 decades are comparatively evaluated: increasing advance rate of longwall faces, increasing machine time of integrated face systems by at least 20%, improving design of powered supports for eliminating rock falls, development of heavy-duty face systems for longwall mining with hydraulic stowing, development of face systems for mining thick coal seams on their whole thickness, slice mining thick coal seams with artificial roofs, bidirectional longwall mining by shearer loaders, use of more elastic and reliable mining systems.

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

Effect of lithological variations of mine roof on chock shield support using numerical modeling technique

Energy Technology Data Exchange (ETDEWEB)

NONE

2006-09-15

Interaction between chock shield supports, the most popular powered supports in Indian longwall mines, and surrounding coal measure strata is analyzed using finite element models. Thickness and material properties of the main roof, the immediate roof and the coal seam are varied to simulate various geological conditions of Indian coal measure strata. Contact/gap elements are inserted in between the main roof and overburden layer to allow strata separation. Nonlinear material properties are applied with plastic corrections based on Drucker-Prager yield criterion. This paper illustrates effects of lithological variations on shield load, abutment stress, yield zone and longwall face convergence.

Rock mechanics research in the Coeur d'Alene mining district

Energy Technology Data Exchange (ETDEWEB)

Corp, E. L.

1980-05-15

Over the past 20 years, the Bureau of Mines and mining companies of the Coeur d'Alene district have conducted cooperative research on problems of ground control. For the past six years emphasis has been placed on research to improve deep shaft design and to control rock bursts during cut-and-fill stoping. Finite-element modeling and construction of small-scale circular and rectangular test shafts have shown that circular openings are stable only when stresses are hydrostatic or weakly biaxial. Under a strongly-biaxial horizontal stress field, a rectangular shaft has a greater depth capability if its long axis can be oriented parallel to the major stress and normal to the bedding and joint system. Steel sets appear preferable to wood sets or concrete lining. Based on underground tests at Hecla's Star mine, destressing or preconditioning of the vein rock prior to mining was shown to be an effective means of controlling rock bursts. Drilling and shooting a radial pattern of longholes before stope mining starts has preconditioned or softened the vein material to the extent that seismic energy release during mining is reduced and no bursting occurred. Increased burst and seismic activity while mining about the preconditioned zone points out the need to precondition an entire stope block before mining.

Tomographic imaging of rock conditions ahead of mining using the shearer as a seismic source - A feasibility study

Energy Technology Data Exchange (ETDEWEB)

Luo, X.; King, A.; Van de Werken, M. [CSIRO, Brisbane, Qld. (Australia)

2009-11-15

Roof falls due to poor rock conditions in a coal longwall panel may threaten miner's life and cause significant interruption to mine production. There has been a requirement for technologies that are capable of imaging the rock conditions in longwall coal mining, ahead of the working face and without any interruption to production. A feasibility study was carried out to investigate the characteristics of seismic signals generated by the continuous coal cutter (shearer) and recorded by geophone arrays deployed ahead of the working face, for the purpose of seismic tomographic imaging of roof strata condition before mining. Two experiments were conducted at a coal mine using two arrays of geophones. The experiments have demonstrated that the longwall shearer generates strong and low-frequency (similar to 40 Hz) seismic energy that can be adequately detected by geophones deployed in shallow boreholes along the roadways as far as 300 m from the face. Using noise filtering and signal cross correlation techniques, the seismic arrival times associated with the shearer cutting can be reliably determined. It has proved the concept that velocity variations ahead of the face can be mapped out using tomographic techniques while mining is in progress.

Mining of sedimentary-type ore deposits

International Nuclear Information System (INIS)

Bruha, J.; Slovacek, T.; Berka, J.; Sadilek, P.

1992-01-01

A procedure is proposed for mining sedimentary-type ore deposits, particularly uranium deposits, using the stope-pillar technique. The stope having been mined out, the free room is filled with hydro-setting gob from the surface. A precondition for the application of this technique is horizontal ore mineralization in sediments where the total thickness of the mineralized ore layer is at least 3 to 5 m. Mining losses do not exceed 5%. For thicknesses greater than 5 m, the roof is reinforced and the walls are secured with netting. The assets of the technique include higher labor productivity of the driving, lower material demands in reinforcing and filling, lower power consumption, and reduced use of explosives. (Z.S.). 3 figs

The effect of the gas factor on selecting the thickness of a layer during two-layer getting of thick seams. [USSR

Energy Technology Data Exchange (ETDEWEB)

Varekha, Zh P; Kurkin, A S; Vechera, V N

1979-01-01

For technico-economic verification of the selection of the efficient removed thickness of upper and lower layers under conditions of high gas abundance of seams, the KNIUI has developed an economic model of converted costs within a getting field, allowing for natural and technical factors. The calculation considers specific costs for stoping work when getting the upper and lower layers, digging and maintenance of development workings, coal transport, assembly-disassembly work, ventilation, labor costs, degassing, etc. The calculation dependences and nomogram obtained enable comparatively easy definition of efficient thicknesses of removed layers when designing stoping work at thick, gently sloping seams, as well as calculation converted costs using as the initial data the total thickness of the seam, its natural gas content, and the expected degree of preliminary degassing.

Principles of safe mechanization of operations in seams with hazards of rock and gas outbursts

Energy Technology Data Exchange (ETDEWEB)

Kozlowski, B; Siarkiewicz, R

1976-10-01

Rock burst hazards in Lower Silesia, Poland, and methods for rock burst forecasting are discussed. From 1894 to 1974, 1403 rock bursts occurred in the basin; five were accompanied by emission of methane, the rest with emission of carbon dioxide. Use of the GMA-030 sensor system (type GfG) for detecting increasing emission of carbon dioxide at longwall faces mined by coal plows is analyzed. Site selection for sensors at longwall faces (retreat or advance) in mines with ascending or descending ventilation, with blowing or exhaust ventilation systems and in mine drivage is analyzed. Examples of sensor installation at face ends are evaluated. Recommendations for sensor installation are made. 2 references.

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.

Selection of powered roof support for weak coal roof

Energy Technology Data Exchange (ETDEWEB)

Ramayya, M.S.V.; Sudhakar, L. [Singareni Collieries Co. Ltd., Kothagudem (India)

2002-04-01

Singareni Collieries Company Ltd (SCCL) introduced mechanised longwall mining in 1983. The first few faces were worked with conventional and immediate forward supports (IFS), with capacities in the range of 360 to 450 t. These under capacity supports increased from abutment loads and there was breakage of roof in front of the supports which resulted in closure of powered roof supports, followed by face cavities. The cavities were more frequent and were difficult to negotiate especially in case of IFS supports. Subsequently, support capacity was increased at Padmavati Khani (PVK) mine and at GDK.10a and GKD.9LFP Inclines where the roof is composed of weak, coal, shale and clay. Problems related to failure of hydraulics/legs etc., which are repairable have occurred; though the problems are not totally eliminated, there was definite improvement in strata control with these higher capacity supports. Monitoring of supports was conducted all through the working of longwall panels. The data generated while working these longwall faces were analysed to study the suitability of other types of powered roof supports, namely 2 legged shield supports/4 legged supports for improved strata control. The analysis and practical experiences suggest that in weak, coaly, shale and clay roofs 2 legged shield supports offer better roof control. 4 refs., 4 figs.

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...

Effective roof support for tabular stopes.

CSIR Research Space (South Africa)

Ottermann, RW

2002-09-01

Full Text Available hydraulic press of the servo hydraulic test facility of the University of Pretoria. The yielding mechanism was compressed at a constant speed of 10 mm/min and the force displacement characteristics was recorded. See figure 4-18. After reaching... damper absorbing the forces. The test of the yielding mechanism was done in a servo hydraulic press as described in paragraph 4.4.2. 5.1.2 Laboratory tests The load cycle chosen for the testing of the structure of the roof support system was: 5...

Uptake and early removals of Implanon NXT in South Africa ...

African Journals Online (AJOL)

coverage over the past two decades.[3,4]. In South Africa (SA), .... with dealing with implant side-effects, counselling and management, and removal. ..... social franchising: The experience of Marie Stopes International in Mali. Glob Health: Sci ...

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...

Deep gold mine fracture zone behaviour

CSIR Research Space (South Africa)

Napier, JAL

1998-12-01

Full Text Available The investigation of the behaviour of the fracture zone surrounding deep level gold mine stopes is detailed in three main sections of this report. Section 2 outlines the ongoing study of fundamental fracture process and their numerical...

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.

Fiscal 1997 technological survey report. Engineer exchange project - coal mine technological field (Advanced coal producing country survey - U.S.A. survey); 1997 nendo gijutsusha koryu jigyo (tanko gijutsu bun'ya) senshin santankoku chosa. Beikoku chosa

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-03-01

While the introduction and adaptation of the Longwall excavation technology were carried forward for coal producing countries in the Pacific region, U.S.A. information was collected by making tours of coal mines in the West and Washington/Colorado/Utah States, with the intention of ascertaining technological trend so as to carry out efficient technological transfer, and for the purpose of replenishing the contents and contributing to the smooth implementation of the engineer exchange project in 'coal mine technological field'. The coal reserves are 400 billion tons, with 840 million tons produced and with 80 million tons exported; not less than 56% of the U.S. domestic electricity rests on coal. Production by open-pit mining is the majority while the output by underground mining is 38%; the Longwall method has increased as a digging method, taking 18% of all digging output. The productivity is 4.24 ton/person per day and ranks as the world highest. The coal mining technological trend in the U.S. can be summarized as follows. The coal mining output in the West is increasing, with the number of mines decreasing, so that the output per mine is increasing. With the output ratio by open-pit mining increasing, the digging method in the mine is being changed to the Longwall. (NEDO)

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...

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.

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

Stress measurements in the Naesliden Mine

Energy Technology Data Exchange (ETDEWEB)

Leijon, B. [Univ. of Luleaa, Sweden; Carlsson, H.; Myrvang, A.

1980-05-15

Determinations of virgin stresses were performed at an early stage of the Naesliden Project in order to obtain input data for the finite element models of the mine. The Leeman three-dimensional overcoring technique was used at five locations on levels ranging from 210 m to 460 m below surface. Stress data were obtained at four of these locations. The results show an excess of horizontal stresses whilst the vertical stress is in accordance with the gravitational load from the overburden. The major and intermediate principal stresses are sub-horizontal and directed respectively perpendicular and parallel to the schisotsity of the wall rock and the strike of the tabular ore body. The minor principal stress is directed almost vertically. Stresses were also measured close to a stope on 300 m level in the mine. Biaxial and triaxial overcoring measurements were made at eighteen points between 0.25 m and 7.2 m above the roof of the stope. The stresses were found to have magnitudes of about 70 MPa close to the roof and to decrease rapidly with the distance from the roof. Stress measurements were made in connection with slot blastings in the foot wall, the latter measure being made in an attempt to de-stress the roof of stope 3. Two methods were used for stress monitorings, both showing that expected stress changes did not take place. Long-term stress guages have been installed in the ore body in order to monitor expected re-distributions of stresses due to mining. So far, the recorded stress changes are below 5 MPa.

Violent failure of a remnant in a deep South African gold mine

CSIR Research Space (South Africa)

Durrheim, RJ

1998-04-15

Full Text Available and collapsed when subjected to intense seismic shaking. This response was due to the presence of a bedding-parallel fault and calcite-coated joints in the vicinity of a 'roll'. The stope support system failed to contain the seismically fragmented rock....

Novel sensors for underground robotics

CSIR Research Space (South Africa)

Green, JJ

2012-08-01

Full Text Available The end state of an autonomous system in South Africa’s deep mines is a “fait accompli”. The current unacceptable safety records, and the increasing dangers as the mines get deeper, necessitate the removal of miners from the dangerous stope areas...

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...

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...

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.

Strata control in deep coal mines. Control de estratos en tajos subteraneos de la mineria del carbon

Energy Technology Data Exchange (ETDEWEB)

Ramirez Oyanguren, P.; De la Cuadra, L.

1985-01-01

The six chapters cover the following subjects: mining methods used in Spanish coal mines; rock movement and pressure around a longwall face; roof bed study; underground support systems; gas dynamic phenomena; and instrumentation for underground mine monitoring.

Systemic lupus erythematosus and myelofibrosis: A case report and revision of literature

Directory of Open Access Journals (Sweden)

F. Del Porto

Full Text Available Blood cytopenia represents one of the diagnostic criteria for systemic lupus erythematosus (SLE and may occur as the first symptom of the disease. Antibody-mediated peripheral destruction of blood cells is the main cause of cytopenia observed in patients affected by SLE, however, inflammatory anemia, nutritional deficiencies, immunosuppressive therapy and, more rarely, myelofibrosis (MF have also been documented. In the literature, 45 cases of autoimmune MF (AIMF and SLE have been previously reported. Here the 46th case of a 43-year-old female with a SLE and an underhand cytopenia, with a review of the literature. Keywords: Systemic lupus erythematosus, Autoimmune myelofibrosis, Blood cytopenia

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...

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 ...

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...

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...

Towards the prediction of pre-mining stresses in the European continent. [Estimates of vertical and probable maximum lateral stress in Europe

Energy Technology Data Exchange (ETDEWEB)

Blackwood, R. L.

1980-05-15

There are now available sufficient data from in-situ, pre-mining stress measurements to allow a first attempt at predicting the maximum stress magnitudes likely to occur in a given mining context. The sub-horizontal (lateral) stress generally dominates the stress field, becoming critical to stope stability in many cases. For cut-and-fill mining in particular, where developed fill pressures are influenced by lateral displacement of pillars or stope backs, extraction maximization planning by mathematical modelling techniques demands the best available estimate of pre-mining stresses. While field measurements are still essential for this purpose, in the present paper it is suggested that the worst stress case can be predicted for preliminary design or feasibility study purposes. In the Eurpoean continent the vertical component of pre-mining stress may be estimated by adding 2 MPa to the pressure due to overburden weight. The maximum lateral stress likely to be encountered is about 57 MPa at depths of some 800m to 1000m below the surface.

The Alabama, U.S.A., seismic event and strata collapse of May 7, 1986

Science.gov (United States)

Long, L.T.; Copeland, C.W.

1989-01-01

On May 7, 1986, the residents of Tuscaloosa, Alabama, felt a seismic event of local magnitude 3.6 that occurred at the same time as a rock burst and roof collapse in an active longwall coal mine. Visual inspection of the seismograms reveals a deficiency in energy at frequencies above 20 Hz compared to tectonic earthquakes or surface blasts. The predominance of energy below 5 Hz may explain reports of body wave magnitudes (mb) greater than 4.2. Also, 1.0 Hz surface waves were more strongly excited than body waves and may explain local felt effects more typically associated with greater epicentral distances. All recorded first motions were dilatational. The concentration of stations in the northern hemisphere allows reverse motion on an east-trending near-vertical plane or strike-slip motion on northwest or southeast trending planes. The reverse focal mechanism is preferred, because the area of roof collapse and the area of active longwall mining are located between two east-striking loose vertical fracture zones. The characteristics of the seismic event suggest that it might have been sudden shear failure resulting from accumulated strain energy in overlying strata behind an active longwall. Although an alternate interpretation of the focal mechanism as an implosion or shear failure in the strata above previously mined out areas is also allowed by the first motion data, this alternate intepretation is not supported by geological data. ?? 1989 Birkha??user Verlag.

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.

Protection of mechanized timberings on beds dangerous for mine impacts

Energy Technology Data Exchange (ETDEWEB)

Budirsky, S

1982-01-01

In some stoping faces on beds which are dangerous for mine impacts, mechanized timbering is successfully used which is not equipped with protection from the effect of these dynamic phenomena. This generated the idea that in the indicated conditions, mechanized timbering may not be equipped with protective devices against dynamic loads. Theoretical studies have shown that the effects of mine impacts depends on the total energy of the impact, distance of this stoping face from the epicenter of the impact, as well as the capacity of the rock massif to transmit and absorb energy of the mine impact. This means that the effect of the mine impact under different conditions is not the same, the mine impacts of lower energy under definite conditions can result in greater damages to the mechanized timbering than mine impact with higher energy. It is believed that the effect of absorption of energy of the mine impact depends on the method of control of the roofing in the stoping face, the presence of hydraulic fill quarantees absorption of up to 80% of its energy. The experience of working beds which are dangerous for mine impacts in the upper Silesia coal basin indicated that the designs of the mechanized timbering, especially shield, in which the stands are not rigidly connected to the roof timber, during operation on beds with thickness 2.5-4 m withstand mine impacts with energy 10/sup 7/ J without significant disorders (mine impacts with this energy occur very frequently . For energy of mine impact of 108 J (impacts with this energy are observed comparatively rarely), the mechanized timberings are considerably damaged.

Rock mechanics research in the Coeur d'Alene mining district

Energy Technology Data Exchange (ETDEWEB)

Corp, E. L.

1980-05-15

Over the past 20 years, the Bureau of Mines and mining companies of the Coeur d'Alene district have conducted cooperative research on problems of ground control. For the past six years emphasis has been placed on research to improve deep shaft design and to control rock bursts during cut-and-fill stoping. Factors contributing to ground control problems include: depth of mining ranging to 8000 feet; local tectonic activity that in many instances has produced horizontal stresses exceeding the vertical; unequal horizontal stresses at ratios ranging between 1.25 and 2.73; major faults, joints, and bedding planes; and hard, brittle quartzite rock capable of concentrating high levels of stress. Finite-element modeling and construction of small-scale circular and rectangular test shafts have shown that circular openings are stable only when stresses are hydrostatic or weakly biaxial. Under a strongly-biaxial horizontal stress field, a rectangular shaft has a greater depth capabiity if its long axis can be oriented parallel to the major stress and normal to the bedding and joint system. Steel sets appear preferable to wood sets or concrete lining. Based on underground tests at Hecla's Star mine, destressing or preconditioning of the vein rock prior to mining was shown to be an effective means of controlling rock bursts. Drilling and shooting a radial pattern of longholes before stope mining starts has preconditioned or softened the vein material to the extent that seismic energy release during mining is reduced and no bursting occurred. Increased burst and seismic activity while mining above the preconditioned zone points out the need to precondition an entire stope block before mining.

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.

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...

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

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

Mining robotics sensors

CSIR Research Space (South Africa)

Green, JJ

2012-04-01

Full Text Available of threedimensional cameras (SR 4000 and XBOX Kinect) and a thermal imaging sensor (FLIR A300) in order to create 3d thermal models of narrow mining stopes. This information can be used in determining the risk of rockfall in an underground mine, which is a major...

Compositional differences between roof and floor rocks of the Skaergaard Intrusion

DEFF Research Database (Denmark)

Salmonsen, Lars Peter; Tegner, Christian; Barfod, Gry

2014-01-01

of stoped gneissic blocks. Our new Sr and Nd data of the Upper Border Series exclude this as a first order process as has been shown before. Mixing models suggest that the Layered and Upper Border Series assimilated less than 3 percent Precambrian host gneiss. Furthermore, no correlation exists between...

New technologies of mining stratal minerals and their computation

Science.gov (United States)

Beysembayev, K. M.; Reshetnikova, O. S.; Nokina, Z. N.; Teliman, I. V.; Asmagambet, D. K.

2018-03-01

The paper considers the systems of flat and volumetric modeling of controlling long-wall faces for schemes with rock collapse of the immediate and main roof and smooth lowering of the remaining layers, as well as in forming a vault over the face. Stress distributions are obtained for the reference pressure zone. They are needed for recognizing the active state of the long-wall face in the feedback mode. The project of the system “support - lateral rocks” is represented by a multidimensional network base. Its connections reflect the elements of the system or rocks, workings, supports with nodes and parts. The connections reflect the logic of the operation of machines, assemblies and parts, and the types of their mechanical connections. At the nodes of the base, there are built-in systems of object-oriented programming languages. This allows combining spatial elements of the system into a simple neural network.

77 FR 24673 - Grand Mesa, Uncompahgre and Gunnison National Forests; Colorado; Federal Coal Lease Modifications...

Science.gov (United States)

2012-04-25

..., topography, hydrogeology, and hydrology identified in the baseline assessment to mining activities in the... coal estate managed by the BLM. The proposed action deals primarily with underground mining. It is assumed that longwall mining practices would be used. Surface disturbance may include soil subsidence due...

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...

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.

Design guidelines for multi-seam mining at Elliot Lake

International Nuclear Information System (INIS)

Hedley, D.G.F.

1978-04-01

With the current expansion in uranium mining, multi-seam mining could again be practised at Elliot Lake as it was in the 1960s. Information on the dimensions of stopes, pillars, and parting zone was gathered from plans and sections of the relevant closed mines. Discussions were held with personnel familiar with these mines to establish instances of pillar, roof, and parting zone failures. Design guidelines are formulated for stope and pillar dimensions in multi-seam mining for a range of orebody configurations using past practice in a back-analysis approach. Constraints imposed by dip and seam thickness on the choice of equipment and mining layout are evaluated. An attempt is made to bring together the engineering aspects, including rock mechanics, of multi-seam mine design with uranium recovery and other economic factors for three alternative mine layouts: single-seam mining, double-seam mining, and seams-and-parting mining. A series of examples are worked through, showing how the design guidelines can be applied for typical orebody configurations

Naesliden Project: rock mechanics observations and measurements in the Naesliden mine

Energy Technology Data Exchange (ETDEWEB)

Nilsson, G.; Krauland, N.

1980-05-15

Observations and measurements of the reaction of the rock mass to mining have been made in the Naesliden Mine since the very start of mining operations in 1970. This observation program originated in the need of better understanding of the rock mechanics of cut-and-fill mining. The program comprises the following types of measurement - in the backfilled excavation convergence of the sidewalls pressure in the fill - in the orebody and alteration zones above the stopes horizontal deformation of the orebody and of the adjoining alteration zones horizontal stresses changes in horizontal stresses - in the stope amount and direction of roof and sidewall displacements convergence and sidewall deformation successively in roof and floor - in the sidewall surface subsidence horizontal displacements at 260 m level. Purpose, extent, methods and results of measurements are described. Qualitative observations concerning fracture processes due to mining are reported. The results are discussed and used for estimation of in situ modulus of elasticity of the orebody as well as the ratio of the modulus of elasticity of the orebody to the modulus of the alteration zone.

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.

Stress Distribution in a Coal Seam before and after Bump Initiation

Directory of Open Access Journals (Sweden)

J. Vacek

2001-01-01

Full Text Available This paper deals with to the behaviour of open rock that occurs, for example, during longwall mining in coal mines, in deep tunnel, or shaft excavation.Longwall instability leads to extrusion of rock mass into an open space. This effect is mostly referred to as a bump, or a rock burst. For bumps to occur, the rock has to possess certain particular rock burst properties leading to accumulation of energy and the potential to release this energy. Such materials may be brittle, or the bumps may arise at the interfacial zones of two parts of the rock, that have principally different material properties.The solution is based on experimental and mathematical modelling. These two methods have to allow the problem to be studied on the basis of three presumptions: – the solution must be time dependent – the solution must allow the creation of crack in the rock mass – the solution must allow an extrusion of rock into an open space (bump effect

Coal mine subsidence

International Nuclear Information System (INIS)

Darmody, R.G.; Hetzler, R.T.; Simmons, F.W.

1992-01-01

Longwall coal mining in southern Illinois occurs beneath some of the best agricultural land in the U.S. This region is characterized by highly productive, nearly level, and somewhat poorly drained soils. Subsidence from longwall mining causes changes in surface topography which alters surface and subsurface hydrology. These changes can adversely affect agricultural land by creating wet or ponded areas that can be deleterious to crop production. While most subsided areas show little impact from subsidence, some areas experience total crop failure. Coal companies are required by law to mitigate subsidence damage to cropland. The objective of this paper is to test the effectiveness of mitigation in restoring grain yields to their pre-mined levels. The research was conducted on sites selected to represent conventional mitigation techniques on the predominate soils in the area. Corn (Zea mays L.) and soybean [Glycine max.(L.) Merr] yields in 1988, 1989, 1990, and 1991 from mitigated areas were compared to yields from nearby undisturbed areas

Application of EMD-Based SVD and SVM to Coal-Gangue Interface Detection

Directory of Open Access Journals (Sweden)

Wei Liu

2014-01-01

Full Text Available Coal-gangue interface detection during top-coal caving mining is a challenging problem. This paper proposes a new vibration signal analysis approach to detecting the coal-gangue interface based on singular value decomposition (SVD techniques and support vector machines (SVMs. Due to the nonstationary characteristics in vibration signals of the tail boom support of the longwall mining machine in this complicated environment, the empirical mode decomposition (EMD is used to decompose the raw vibration signals into a number of intrinsic mode functions (IMFs by which the initial feature vector matrices can be formed automatically. By applying the SVD algorithm to the initial feature vector matrices, the singular values of matrices can be obtained and used as the input feature vectors of SVMs classifier. The analysis results of vibration signals from the tail boom support of a longwall mining machine show that the method based on EMD, SVD, and SVM is effective for coal-gangue interface detection even when the number of samples is small.

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

Thin seam mining

Energy Technology Data Exchange (ETDEWEB)

Sikora, W [Politechnika Slaska, Gliwice (Poland). Instytut Mechanizacji Gornictwa

1989-06-01

Discusses thin seam mining in Poland and its prospects. There were 194 working faces in coal seams to 1.5 m thick in Poland in 1988. Of them, 115 fell on faces with powered supports, 79 on faces with SHC-40 and Valent props; 108 shearer loaders and 45 coal plows were used for longwall mining of thin coal seams. Drilling and blasting was used to mine 21 working faces. Longwall faces in seams to 1.0 m thick gave 2.0% coal output, faces in coal seams 1.01-1.5 m thick gave 12.2% of daily coal output of underground mining. Structure of daily coal output of faces in thin seams was the following: 52 faces below 300 t/day, 42 from 301-500 t/day, 63 from 501 to 1,000 t/day, 17 faces above 1,000 t/day. Prospects for increasing coal output of faces in thin seams are discussed. 7 refs.

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...

Underground coal equipment

Energy Technology Data Exchange (ETDEWEB)

Chadwick, J.

2002-12-01

This paper reports on increasing automation and enhanced productivity on longwalls, new development cutting and bolting technologies and haulage systems. Amongst equipment discussed is DBT's Electra series EL3000 shearer, the Dosco LH1400 roadheader with onboard bolters, and Joy 12 CM30 continuous miners. 4 photos.

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.

Marie Stopes International Child Spacing Clinics in Malawi

African Journals Online (AJOL)

distributed > 200,000 condoms, completed programmes in more than 30 ... that men feel that child spacing is also their concern and service providers feel men are .... there is often the denial of the fact that their child is sexually active inspite of ...

Geostatistical modeling of the gas emission zone and its in-place gas content for Pittsburgh-seam mines using sequential Gaussian simulation

Science.gov (United States)

Karacan, C.O.; Olea, R.A.; Goodman, G.

2012-01-01

Determination of the size of the gas emission zone, the locations of gas sources within, and especially the amount of gas retained in those zones is one of the most important steps for designing a successful methane control strategy and an efficient ventilation system in longwall coal mining. The formation of the gas emission zone and the potential amount of gas-in-place (GIP) that might be available for migration into a mine are factors of local geology and rock properties that usually show spatial variability in continuity and may also show geometric anisotropy. Geostatistical methods are used here for modeling and prediction of gas amounts and for assessing their associated uncertainty in gas emission zones of longwall mines for methane control.This study used core data obtained from 276 vertical exploration boreholes drilled from the surface to the bottom of the Pittsburgh coal seam in a mining district in the Northern Appalachian basin. After identifying important coal and non-coal layers for the gas emission zone, univariate statistical and semivariogram analyses were conducted for data from different formations to define the distribution and continuity of various attributes. Sequential simulations performed stochastic assessment of these attributes, such as gas content, strata thickness, and strata displacement. These analyses were followed by calculations of gas-in-place and their uncertainties in the Pittsburgh seam caved zone and fractured zone of longwall mines in this mining district. Grid blanking was used to isolate the volume over the actual panels from the entire modeled district and to calculate gas amounts that were directly related to the emissions in longwall mines.Results indicated that gas-in-place in the Pittsburgh seam, in the caved zone and in the fractured zone, as well as displacements in major rock units, showed spatial correlations that could be modeled and estimated using geostatistical methods. This study showed that GIP volumes may

30 CFR 75.814 - Electrical protection.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Electrical protection. 75.814 Section 75.814... Longwalls § 75.814 Electrical protection. (a) High-voltage circuits must be protected against short circuits... with— (i) Ground-fault protection set to cause deenergization at not more than 40 percent of the...

Shearer drums - the cutting edge

Energy Technology Data Exchange (ETDEWEB)

O' Neill, M.; Wright, C.

2004-09-15

The paper discusses continuous miner and shearer cutters. It claims cutting drum require the same level of engineering know-how and technical expertise as do the machines driving them, and that the cutting drum, whether on a longwall shearer or continuous miner, comprises, the steel, pedestals, bit holders and the bits.

Validation of choice and determination of geotechnology parameters with regard to stress–strain state of rocks

Science.gov (United States)

Freidin, AM; Neverov, SA; Neverov, AA; Konurin, AI

2018-03-01

The paper illustrates efficiency and reliability of types of rock mass stress state conditioned by geological and structural features of rocks in design, selection and validation of geotechnology parameters. The authors of the paper present calculation of stresses in rock mass under sublevel stoping depending on the type of the geosphere and on the depth of the ore body occurrence.

Experimental Study and Engineering Practice of Pressured Water Coupling Blasting

Directory of Open Access Journals (Sweden)

J. X. Yang

2017-01-01

Full Text Available Overburden strata movement in large space stope is the major reason that induces the appearance of strong mining pressure. Presplitting blasting for hard coal rocks is crucial for the prevention and control of strong pressure in stope. In this study, pressured water coupling blasting technique was proposed. The process and effect of blasting were analyzed by orthogonal test and field practice. Results showed that the presence of pressure-bearing water and explosive cartridges in the drill are the main influence factors of the blasting effect of cement test block. The high load-transmitting performance of pore water and energy accumulation in explosive cartridges were analyzed. Noxious substances produced during the blasting process were properly controlled because of the moistening, cooling, and diluting effect of pore water. Not only the goal of safe and static rock fragmentation by high-explosive detonation but also a combination of superdynamic blast loading and static loading effect of the pressured water was achieved. Then the practice of blasting control of hard coal rocks in Datong coal mine was analyzed to determine reasonable parameters of pressured water coupling blasting. A good presplitting blasting control effect was achieved for the hard coal rocks.

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.

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.

High tech conveyors unitize Selby coal

Energy Technology Data Exchange (ETDEWEB)

1985-10-01

Designs proposed by Anderson Strathclyde PLC and Cable Belt for single-flight conveyors to bring the output of the five Selby mines to the surface have both been developed by the UK National Coal Board. Both designs extend the limits of conveyor technology and are expected to economise on transport and longwalling costs. 4 references.

New means of communication for working faces

Energy Technology Data Exchange (ETDEWEB)

Brzozka, E.; Kaluzny, M.; Paluch, A.

1987-11-01

Discusses development of communications systems for underground coal mines in Poland and other COMECON countries. Standard communication systems e.g. the GST system for communications at longwall faces (used in Poland since 1976) are described. Two recently developed systems are comparatively evaluated: the EZT-2 system developed in Czechoslovakia and the GSTR system developed in Poland. The EZT-2 system consisting of the EZT-13 stationary equipment and 30 units of a transmitter-receivers (installed on a miner's helmet) is used for radio communications at a working face. The GSTR system developed in Poland is used for radio communications at longwall faces together with the GST, GLT or UGS systems or independently. The system consists of a variable number of transmitters situated along the face and 2 receivers situated in the gate roads. The YLY 1x4 mm/sup 2/ cable is used as an antenna. Design and operation of the GSTR system under operational conditions in a mine in Upper Silesia are evaluated. Effects of surrounding strata on radio wave attenuation are analyzed. 8 refs.

Renovation of production management in Kushiro Colliery

International Nuclear Information System (INIS)

Ito, Kazuyuki

1991-01-01

Kushiro Colliery operates with underground mining as one of the largest coal production in Japan, and supplies to power stations with about 25 % demand of domestic steaming coal. The colliery produces about 80 % raw coal by mechanized longwall mining introduced from 1967 which is composed of Drum Shearer, Shield Supports. A.F.C and Stage Loader. The large scale production by longwall mining brought into various problems on the safety and productivity such as lower coal recovery ratio, deeper coal fields, and the rise of mining cost. Kushiro Colliery have been developed new mining techniques accepted hard-ware and soft ware to improve the coal recovery ratio and to suppress the deeper coal fields. At present, the colliery is strongly performing higher efficiency and safety of mine management by means of the reformation of working systems, the early construction of main roadways for new coal field and intensive transportations, and the completion of safety education. Realization of various mining techniques have been pulled through the reduction of mining cost and managing innovation on the serious colliery management. (author)

Possibility of increasing intensity of mining by mechanization with use of shearer loaders

Energy Technology Data Exchange (ETDEWEB)

Sikora, W; Jaszczuk, M

1981-10-01

Discusses methods of increasing productivity of face systems in longwall mining. Feasibility of increasing coal output by variation of shearer loader haulage speed is analyzed. Effects of haulage speed variation on energy consumption or cutting tool wear are not considered. It is assumed that haulage speed does not depend on advance rate of the powered supports or the rate of face conveyor advance. Mathematical equations are derived for calculation of the optimum haulage speed variations. The method consists in use of variable haulage speed optimized for a given section of a longwall face without overloading the conveyor drive system. Situations with single drum shearer loaders and with bi-directional shearer loaders with cutting drums situated at both ends of the shearer are analyzed. Analyses show that by haulage speed variation shearer loader productivity is significantly increased. Performance tests under operational conditions show that in the case of a bi-directional shearer loader productivity increases by 31% and in the case of a shearer loader with a single drum by 11%. (4 refs.) (In Polish)

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

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.

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

76 FR 37838 - Petitions for Modification of Application of Existing Mandatory Safety Standards

Science.gov (United States)

2011-06-28

... point at least 50 feet above the seam being mined, the petitioner will fracture at least six places at... roof, rib and floor to within 20 feet of the face when mining through the well. On longwall sections, rock dusting will be conducted and placed on the roof, rib, and floor up to the headgate and the...

Designing for success

Energy Technology Data Exchange (ETDEWEB)

Altounyan, P.; Hurt, K.; Bigby, D. [Rock Mechanics Technology, Stanhope Bretby (United Kingdom)

1999-07-01

Successful underground coal mining is dependent on a number of key factors, particularly geotechnical suitability. The impact of rock mechanics on underground mine design and mining methods is discussed in this article. Methods on minimising stress effects in room and pillar mining, and longwall mining are outlined. The use of computer numerical modelling in mine design is mentioned. 8 figs.

Modeling stress–strain state of rock mass under mining of complex-shape extraction pillar

Science.gov (United States)

Fryanov, VN; Pavlova, LD

2018-03-01

Based on the results of numerical modeling of stresses and strains in rock mass, geomechanical parameters of development workings adjacent to coal face operation area are provided for multi-entry preparation and extraction of flat seams with production faces of variable length. The negative effects on the geomechanical situation during the transition from the longwall to shortwall mining in a fully mechanized extraction face are found.

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

Directory of Open Access Journals (Sweden)

Azmat SK

2013-01-01

Full Text Available Syed Khurram Azmat, Waqas Hameed, Ghulam Mustafa, Wajahat Hussain, Aftab Ahmed, Mohsina BilgramiMarie Stopes Society, Research and Metrics Department, Technical Services, Karachi, Sindh, PakistanBackground: 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.Methods: 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.Results: 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.Conclusion: Early

The perception of hazard. I. Hazard analysis and the contribution of visual search to hazard perception

Energy Technology Data Exchange (ETDEWEB)

Blignaut, C J.H.

1979-09-01

This is a study of the ability of miners to perceive warnings of imminent danger that a fall of rock will occur. Features of 745 rock falls (other than outbursts) were studied, and an experiment was carried out on groups of experienced or novice gold miners in a simulated stope. Novice workers, when compared with experienced men, lack the ability to search adequately for dangerous loose rock, but their search skills can be improved significantly by training.

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....

Technical devices of powered roof support for the top coal caving as automation objects

Science.gov (United States)

Nikitenko, M. S.; Kizilov, S. A.; Nikolaev, P. I.; Kuznetsov, I. S.

2018-05-01

In the paper technical devices for the top coal caving as automation objects in the composition of the longwall mining complex (LTCC) are considered. The proposed concept for automation of the top coal caving process allows caving efficiency to be ensured, coal dilution to be prevented, conveyor overloading to be prevented, the shearer service personnel to be unloaded, the influence of the “human factor” to be reduced.

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

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.

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

Relationship between collapse history and ore distribution in Sage Breccia pipe, northwestern Arizona

International Nuclear Information System (INIS)

Brown, N.A.; Mead, R.H.; McMurray, J.M.

1989-01-01

The Sage pipe is similar to other collapse breccia pipes in northern Arizona which have their beginnings in cave systems in the Redwall Limestone. Stoping of successively younger units caused the upward propagation of the pipe and provided the pipe-filling breccia. The Sage pipe extends at least 2,500 ft (762 m) vertically; the horizontal dimensions range from 100 to 300 ft (30.5-91 m), depending on variations in the adjoining host stratigraphy. The composition and distribution of breccia facies suggest a complex collapse history and variability in the mechanics of collapse. Rock failure took place both by block stoping and by decementation of sandstone and siltstone followed by flow of unconsolidated grains. The resulting breccias range from matrix to fragment-dominated, to sand flow breccia resulting from flow of individual grains. Episodic secondary collapse or readjustment within the breccia pile complicated facies distribution. Paragenetic studies indicate multiple periods of mineralization at Sage resulting in enrichment in an extensive suite of elements. Ore-grade uranium mineralization extends vertically for nearly 700 ft (213 m). Lateral distribution of the ore is variable and is directly related to breccia facies distribution. In generally, the more permeable breccias tend to be the most highly mineralized. Fracture, intergranular, and interfragment permeability were important to mineral distribution. Breccia continuity or plumbing was also important to lateral and vertical mineral distribution

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.

Mine safety sensors: Test results in a simulated test stope

CSIR Research Space (South Africa)

Dickens, J

2013-10-01

Full Text Available The South African mining industry is plagued by accidents, the most common of which are rock falls. In order to carry out its mandate of improving the quality of life of South African citizens, the Council for Scientific and Industrial Research...

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 with strain bursting conditions, while low values (< 0.1) are associated with significant risks of falls of ground. The typical closure ratio calculated for the experimental site at Mponeng Mine was 0.5. Fortunately no face bursting occurred during... the period of monitoring but any possible changes in closure ratio preceding bursts could therefore not be investigated. Another preliminary finding is that it appears that the closure ratio is relatively independent of position along the stope face...

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.

An investigation into recharge in South African underground collieries

Energy Technology Data Exchange (ETDEWEB)

Vermeulen, P.D.; Usher, B.H. [University of the Free State, Bloemfontein (South Africa). Inst. of Groundwater Studies

2006-11-15

The Mineral and Petroleum Act of 2002 states that no closure certificate may be issued to mines unless the management of potential pollution to water resources has been addressed. Continuous recharge into the abandoned collieries occurs, and it is important for collieries that close down to plan their future management strategy accordingly. Research has been initiated to determine the recharge into abandoned mines of different mining depths, methods and size. Collieries of a nature similar to these case studies can thus associate with the recharge values obtained. Water balances are of overriding importance in determining recharge and water loss. These vary from mine to mine. Overriding factors are the method of mining, depth of mining, and surface hydrology. High extraction methods (stooping and longwall) invariably disturb the overlying strata more than bord and pillar methods. A summary of the percentage influx to be expected for the various mining methods is as follows: Shallow bord and pillar: 5-10% of the rainfall; Deep bord and pillar with no subsidence: 3-4% of the rainfall; Stooping: 5-12% of the rainfall; Longwall: 6-15% of the rainfall; Rehabilitated opencast: 14-20% of the rainfall. The actual percentages depend largely on specific circumstances.

Protecting mine roadways used for the second time in the Komsomolets Donbassa mine

Energy Technology Data Exchange (ETDEWEB)

Zaslavskii, I Yu; Boev, N A; Churakov, V N

1983-12-01

This paper evaluates methods for strata control in gate roads used in the Komsomolets Donbassa mine with 2 coal seams from 1 to 1.1 m thick at depths of 418 m and 624 m, with dip angles from 5 to 10 degrees. Long pillars are mined by a system of longwall faces with caving. The following methods for strata control in gate roads are comparatively evaluated: use of blocks made of reinforced concrete, use of timber cribbings, combined use of concrete blocks or cribbings and strips of pneumatic stowing from 8 to 12 m wide, use of thin coal support pillars (from 2 to 3 m). Investigation results are shown in 4 diagrams. Analyses show that use of blocks made of reinforced concrete or concrete blocks combined with strips of pneumatic stowing does not prevent excessive roof subsidence and support deformation. Use of coal support pillars from 2 to 3 m wide is not recommended due to considerable cost and coal losses. Use of timber cribbings combined with strips of pneumatic stowing is most expedient. Recommendations on using timber cribbings and pneumatic stowing for strata control in gate roads used by the next longwall face are made. (In Russian)

Methods for protecting mine roadways used by two faces

Energy Technology Data Exchange (ETDEWEB)

Katkov, G A; Dimanshtein, A S

1983-09-01

Use of a mine roadway by two longwall faces reduces mine drivage by half and positively influences ventilation and mine haulage. Economic effects of repeated use of mine roadways depend on strata control cost and repair of support systems damaged or deformed by rock strata stress. Use of strips of pneumatic stowing along mine roadways is uneconomical due to low support strength and significant subsidence of the waste rock strip under rock strata stress. Use of timber cribbings as well as blocks of reinforced concrete for strata control is uneconomical due to their high damage rate and low support capacity. Investigations carried out by the IGD Im. A.A. Skochinski Institute and other research institutes show that use of hardening stowing is superior to other methods for strata control in mine roadways used by two longwall faces. Hardening stowing (on a cement basis) is prepared by the SB-67 or the PBM-2Eh machines and by other systems used for guniting in coal mines. The optimum dimensions of a strip of hardening stowing depend on coal seam thickness and mechanical properties of the surrounding rock strata. Use of hardening stowing successfully controls roof subsidence in mine roadways and reduces support deformation. Examples of hardening stowing use in some Donbass coal mines are discussed.

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

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.

Making the cut

Energy Technology Data Exchange (ETDEWEB)

Mcshannon, G. [Hydra Mining Tools International Ltd. (United Kingdom)

2006-04-15

The paper explains how coal mines around the world can benefit from the use of cowless, radial shearer drums. Hydra Mining has designed and manufactured a range of shearer drums to combat problems ranging from dust, frictional ignitions, geological problems or low production rates. This allows the mine operator to maximise production efficiency. The company tailor-makes shearer drums for each longwall face to optimise the cutting performance of every installation. 8 figs.

Identify and draft outcomes-based training material in strata control for underground workers.

CSIR Research Space (South Africa)

Johnson, RA

2000-03-01

Full Text Available were selected to cover the spread of mining groups, districts, 5 reefs and general diversity of conditions in the gold and platinum mining industries. A full list of the contributors is provided in Appendix D. 4.3 Questionnaire design One... procedures and in drilling of blast and support holes at levels 1 and 2. Similarly stope support, tunnel support, installing support, drilling and blasting and some topics in layouts, barring and geology are covered at levels 3 and 4. The more advanced...

The allocation of gold production from multiple shafts feeding a common treatment plant using run-of-mine sampling of ore deliveries

OpenAIRE

Bartlett, H.E.; Korff, L.; Minnitt, R.C.A.

2014-01-01

Previously, the grade of ore at the shaft head was taken to be equivalent to the grade measured in the faces by means of chip sampling. The tonnage mined from the stopes is determined from survey volumetric measurements. Estimates of shaft head grade and tons include the grades and tons of waste, development ore, sweepings from old areas, and other sources, not all of which are sampled. The tonnage of ore delivered at the shaft is often estimated using skip factors. These factors are subject ...

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

Relationship between motor performance and physical fitness score in 7- to 8-year-old children. DOI: 10.5007/1980-0037.2011v13n2p94

Directory of Open Access Journals (Sweden)

Patrik Felipe Nazario

2011-03-01

Full Text Available There are many tests for the evaluation of motor performance or physical fitness that take into account different criteria such as movement forms and patterns, time, distance, and repetitions of each task for the analysis of performance. The aim of this study was to investigate the relationship between motor performance and physical fitness scores in children. Fifty children of both genders aged 7 to 8 years (25 boys and 25 girls participated in this study. The Test of Gross Motor Development – Second Edition (TGMD-2 was used for the evaluation of motor performance. Physical fitness was assessed by three specific tests proposed by the American Alliance for Health, Physical Education, Recreation and Dance (AAHPERD. The results showed statistical significance and weak correlations among some skills such as run, horizontal jump, hop, leap, underhand roll, and medicine ball throw. The equivalent use of both tests may not be adequate since each test has its own peculiarities in terms of assessment criteria.

Relationship between motor performance and physical fitness score in 7- to 8-year-old children. DOI: 10.5007/1980-0037.2011v13n2p94

Directory of Open Access Journals (Sweden)

Ruy Jornada Krebs

2011-02-01

Full Text Available There are many tests for the evaluation of motor performance or physical fitness that take into account different criteria such as movement forms and patterns, time, distance, and repetitions of each task for the analysis of performance. The aim of this study was to investigate the relationship between motor performance and physical fitness scores in children. Fifty children of both genders aged 7 to 8 years (25 boys and 25 girls participated in this study. The Test of Gross Motor Development – Second Edition (TGMD-2 was used for the evaluation of motor performance. Physical fitness was assessed by three specific tests proposed by the American Alliance for Health, Physical Education, Recreation and Dance (AAHPERD. The results showed statistical significance and weak correlations among some skills such as run, horizontal jump, hop, leap, underhand roll, and medicine ball throw. The equivalent use of both tests may not be adequate since each test has its own peculiarities in terms of assessment criteria.

Maar net nog ’n butch? ’n Feministiese lesing van die Halewijnlied

Directory of Open Access Journals (Sweden)

D. J. Jordaan

1995-04-01

In this article the authors argue that a form of covert feminism is present in the Halewijnlied (Song of Halewijn, an important Middle Dutch text. Utilizing the poststructuralist notion of écriture rather than lecture, the latent content of the text is explored, enabling the authors to (re-construct the ‘meaning' of the text within the context of Kristeva's notion that the Virgin cult constitutes "a triumph of the unconscious in monotheism This "triumph of the unconscious "amounts to a form of female power which is the “underhand double of explicit phallic power" and sets up a temporary "commonality of the sexes" within the patriarchal system. By means of the personage of the Princess, Freudian displacement in terms of social sex roles occurs, negating some of the binary oppositions characterising the man:woman dichotomy. This process results in an 'androgenic’ space in which both sexes are temporarily set free from the sexual roles forced upon them by a patriarchal system.

Review of fill mining technology in Canada

Energy Technology Data Exchange (ETDEWEB)

Singh, K. H.; Hedley, D. G.F.

1980-05-15

The Canadian mining industry has a long history of being in the fore-front in developing new technology in underground hardrock mines. Examples include the development of hydraulic and cemented fills, undercut-and-fill, mechanized cut-and-fill, post pillar, vertical retreat and blasthole mining methods. The evolution of this technology is briefly described in an historical review. Backfill serves many functions, although it is generally considered in terms of its support capabilities. These functions, mainly related to the mining method used, are evaluated in regard to regional support, pillar support, fill roof, working floor, dilution control and waste disposal. With the advent of blasthole and vertical retreat methods for pillar recovery operations, the freestanding height of backfill walls has assumed greater importance. Consequently, more attention is being given to what fill properties are required to achieve fill wall exposures up to 25 m wide by 90 m high. With the large increases in energy costs, alternatives to partially replace Portland cement in fill are being examined. The validation of mining concepts and the interaction of backfill is perhaps best evaluated by in-situ measurements. Examples are given of stress, deformation and fill pressure measurements in longitudinal cut-and-fill, post pillar mining and blasthole stoping with delayed fill which were taken in several mines in Canada. Finally, the overall design procedure used in deciding mining method, stope and pillar dimensions, sequence of extraction, fill properties and support systems at a new mine is described.

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...

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

Analysis of the Harmfulness of Water-Inrush from Coal Seam Floor Based on Seepage Instability Theory

Institute of Scientific and Technical Information of China (English)

无

2007-01-01

A theory of seepage instability was used to estimate the harmfulness of water-inrush from a coal seam floor in a particular coal mine of the Mining Group, Xuzhou.Based on the stratum column chart in this coal mine, the distribution of stress in mining floors when the long-wall mining was respectively pushed along to 100 m and to 150 m was simulated by using the numerical software (RFPA2D).The permeability parameters of the coal seam floor are described given the relationship between permeability parameters.Strain and the water-inrush-indices were calculated.The water-inrush-index was 67.2% when the working face was pushed to 100 m, showing that water-inrush is possible and it was 1630% when the working face was pushed to 150 m, showing that water-inrush is quite probable.The results show that as long-wall mining is pushed along, the failure zone is enlarged, the strain increased, and fissures developed correspondingly, resulting in the formation of water-inrush channels.Accompanied by the failure of the strata, the permeability increased exponentially.In contrast, the non-Darcy flow β factor and the acceleration coefficient decreased exponentially, while the increase in the water-inrush-index was nearly exponential and the harmfulness of water-inrush in the coal mine increased accordingly.

Effects of restructuring of the Polish hard coal industry in 1990-2004; Efekty restrukturyzacji polskiego gornictwa wegla kamiennego w latach 1990-2004

Energy Technology Data Exchange (ETDEWEB)

Olszowski, J. [Mining Chamber of Industry and Commerce (Poland)

2004-07-01

During the period 1990 to 2003 Poland thoroughly restructured its hard coal industry. It reduced production by 77 million tons and employment by 279300; average output was increased from a single longwall by 2046.1 ton/day, and total productivity by 1,741 kg/ms. The balance of liabilities and recoverables was reduced to 6,208.8 million Zl. The article describes the reform of the hard coal industry, in two phases, 1990-1997 and 1998-2003. 11 refs., 6 figs., 1 tab.

Mapping seismic vulnerability in stopes in deep South African gold mines

CSIR Research Space (South Africa)

Durrheim, RJ

2013-09-01

Full Text Available -JICA Science and Technology Research Partnership for Sustainable Development (SATREPS), 2Council for Scientific and Industrial Research, South Africa, 3University of the Witwatersrand, Republic of South Africa, 4Ritsumeikan University, Japan, 5Seismogen cc...

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...

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

CSIR Research Space (South Africa)

Acheampong, E

2002-03-01

Full Text Available ..................................................................................... 5 2.1.1 Link-bar system ...........................................................................................................5 2.1.2 Crank system... joints would be required for this application. There is no flexibility in this system to allow for various advancing distances. The headboard size would not be able to carry the required loads unless large steel sections were used. 2.1.2 Crank system...

30 CFR 18.53 - High-voltage longwall mining systems.

Science.gov (United States)

2010-07-01

...-starter enclosure, with the exception of a controller on a high-voltage shearer, the disconnect device...) shielding between the primary and secondary windings. The shielding must be connected to equipment ground by... with a disconnect device installed to deenergize all high-voltage power conductors extending from the...

World wide developments in shortwall and wide web mining techniques

Energy Technology Data Exchange (ETDEWEB)

Pollard, T

1975-11-01

The paper describes the progress to date with continuous pillar extraction, and how the typical longwall powered support has been modified to be both strong enough and stable enough to provide roof support for very wide webs. It also describes the operating systems which have been specially designed. The next stages of development are discussed, particularly the provision of continuous conveyor haulage in place of the present-day shuttle car. The author suggests that marrying American coal-getting technology and British roof support technology might increase productivity.

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

[Vegetation spatial and temporal dynamic characteristics based on NDVI time series trajectories in grassland opencast coal mining].

Science.gov (United States)

Jia, Duo; Wang, Cang Jiao; Mu, Shou Guo; Zhao, Hua

2017-06-18

The spatiotemporal dynamic patterns of vegetation in mining area are still unclear. This study utilized time series trajectory segmentation algorithm to fit Landsat NDVI time series which generated from fusion images at the most prosperous period of growth based on ESTARFM algorithm. Combining with the shape features of the fitted trajectory, this paper extracted five vegetation dynamic patterns including pre-disturbance type, continuous disturbance type, stabilization after disturbance type, stabilization between disturbance and recovery type, and recovery after disturbance type. The result indicated that recovery after disturbance type was the dominant vegetation change pattern among the five types of vegetation dynamic pattern, which accounted for 55.2% of the total number of pixels. The follows were stabilization after disturbance type and continuous disturbance type, accounting for 25.6% and 11.0%, respectively. The pre-disturbance type and stabilization between disturbance and recovery type accounted for 3.5% and 4.7%, respectively. Vegetation disturbance mainly occurred from 2004 to 2009 in Shengli mining area. The onset time of stable state was 2008 and the spatial locations mainlydistributed in open-pit stope and waste dump. The reco-very state mainly started since the year of 2008 and 2010, while the areas were small and mainly distributed at the periphery of open-pit stope and waste dump. Duration of disturbance was mainly 1 year. The duration of stable period usually sustained 7 years. The duration of recovery state of the type of stabilization between disturbances continued 2 to 5 years, while the type of recovery after disturbance often sustained 8 years.

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 by the number of events. It was found that the Qc dependency on frequency follows a power law. For face events, the power law is given by ( ) 99.006.0 ffQ = and ( ) 58.1003.0 ffQ = for fault slip events. Qc derived from face events was found to be lower than... to be n = 0.99, resulting in the relation: ( ) 99.006.0 ffQ = . For fault slip events, n = 1.58, resulting in the relation: ( ) 58.1003.0 ffQ = . The lower degree of dependency suggests that fractures ahead of the stope face tend to reduce...

Modelling a uranium ore bioleaching process

International Nuclear Information System (INIS)

Chien, D.C.H.; Douglas, P.L.; Herman, D.H.; Marchbank, A.

1990-01-01

A dynamic simulation model for the bioleaching of uranium ore in a stope leaching process has been developed. The model incorporates design and operating conditions, reaction kinetics enhanced by Thiobacillus ferroxidans present in the leaching solution and transport properties. Model predictions agree well with experimental data with an average deviation of about ± 3%. The model is sensitive to small errors in the estimates of fragment size and ore grade. Because accurate estimates are difficult to obtain a parameter estimation approach was developed to update the value of fragment size and ore grade using on-line plant information

Vasectomy: preliminary report on 25 cases.

Science.gov (United States)

Lema, V M; Makokha, A E

1989-05-01

Preliminary data on 25 men who underwent vasectomy for contraception between June 1986 and May 1988 at the Marie Stopes Clinic--Nairobi is presented. The majority (76.0%) of the subjects were aged between 25 and 39 years. 68.0% had 4 living children or less. Professionals including lecturers, lawyers, teachers, engineers etc, formed 88.0% of the total. Three clients(12.0%) had documented complications; one had aseptic wound, one had haematoma and the last one had a failed vasectomy. All were treated successfully. Complications of vasectomy and the need for follow-up of vasectomised men are discussed.

Tube bundle system: for monitoring of coal mine atmosphere.

Science.gov (United States)

Zipf, R Karl; Marchewka, W; Mohamed, K; Addis, J; Karnack, F

2013-05-01

A tube bundle system (TBS) is a mechanical system for continuously drawing gas samples through tubes from multiple monitoring points located in an underground coal mine. The gas samples are drawn via vacuum pump to the surface and are typically analyzed for oxygen, methane, carbon dioxide and carbon monoxide. Results of the gas analyses are displayed and recorded for further analysis. Trends in the composition of the mine atmosphere, such as increasing methane or carbon monoxide concentration, can be detected early, permitting rapid intervention that prevents problems, such as a potentially explosive atmosphere behind seals, fire or spontaneous combustion. TBS is a well-developed technology and has been used in coal mines around the world for more than 50 years. Most longwall coal mines in Australia deploy a TBS, usually with 30 to 40 monitoring points as part of their atmospheric monitoring. The primary uses of a TBS are detecting spontaneous combustion and maintaining sealed areas inert. The TBS might also provide mine atmosphere gas composition data after a catastrophe occurs in an underground mine, if the sampling tubes are not damaged. TBSs are not an alternative to statutory gas and ventilation airflow monitoring by electronic sensors or people; rather, they are an option to consider in an overall mine atmosphere monitoring strategy. This paper describes the hardware, software and operation of a TBS and presents one example of typical data from a longwall coal mine.

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.

Computer-based expert system aids underground mine planning

Energy Technology Data Exchange (ETDEWEB)

Britton, S.G.

1987-04-01

Artificial intelligence (AI) systems have been rapidly expanded over the last few years to aid in the decision making processes in a whole range of industries, including the use of machines for operating in high risk/dangerous areas such as at the working faces in longwall mining. Using Prolog software a program for mine management is being developed called CHOOZ. This system can help managers identify staffing problems and change manpower shifts to cope with unexpected labor problems such as absenteeism and sickness. All the programs have been developed for the IBM PC microcomputer.

Dust-control for thick-seam wall mines.

CSIR Research Space (South Africa)

Belle, BK

2002-02-01

Full Text Available configuration and the belt curtains on the shearer. 3. Install, and evaluate the efficiency of, the physical shield curtains (conveyor belt or other flexible material) hanging from the shield structure inside the shield leg area at every 4th shield to reduce... and 1997, coal production hovered around the 50 million tonnes-a-year level (UK DTI, 2001). Currently, there are 16 producing underground mines in the UK, which includes 15 longwall faces, face lengths range from 250 m to 300 m (Creedy, 2001). Most...

Performance of diamond and point attack coal cutter picks

Energy Technology Data Exchange (ETDEWEB)

Liu, Y. [CSIRO, Brisbane, Qld. (Australia). Division of Exploration and Mining

1996-12-31

This paper presents results of laboratory experiments and field trials of PDC (Polycrystalline Diamond Compact) and PA (Point Attack) coal cutter picks. Laboratory cutting tests included linear rock and coal cutting and turning rock cutting. The following parameters were measured to assess performance of PDC and PA cutter picks: cutting force, normal force, specific energy consumption, yield, dust generation and ignitional characteristics (temperature rise). Field trials were conducted on a longwall shearer. Performance of both types of pick interims of pick life and dust generation were assessed. 3 refs., 18 figs., 3 tabs.

Cutting through - open entries require proper support

Energy Technology Data Exchange (ETDEWEB)

Peng, S.S. [West Virginia University, Morgantown, WV (USA). Mining Engineering Dept.

2000-06-01

The paper explains the applications of open entries in mining and different roof techniques to relieve longwall abutment pressures. The primary support for the open (or cut-through) entries and recovery rooms are normally similar to other development entries in the same mines. The supplementary supports installed can be divided into the following three types: complete backfill of open entries, supplemental roof and/or rib-bolt reinforcement only - no standing support and rows of standing support with or without supplemental roof and/or rib-bolt reinforcement. 3 figs.

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.

The end-state comfort effect in bimanual grip selection.

Science.gov (United States)

Fischman, Mark G; Stodden, David F; Lehman, Davana M

2003-03-01

During a unimanual grip selection task in which people pick up a lightweight dowel and place one end against targets at variable heights, the choice of hand grip (overhand vs. underhand) typically depends on the perception of how comfortable the arm will be at the end of the movement: an end-state comfort effect. The two experiments reported here extend this work to bimanual tasks. In each experiment, 26 right-handed participants used their left and right hands to simultaneously pick up two wooden dowels and place either the right or left end against a series of 14 targets ranging from 14 to 210 cm above the floor. These tasks were performed in systematic ascending and descending orders in Experiment 1 and in random order in Expiment 2. Results were generally consistent with predictions of end-state comfort in that, for the extreme highest and lowest targets, participants tended to select opposite grips with each hand. Taken together, our findings are consistent with the concept of constraint hierarchies within a posture-based motion-planning model.

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.

The use of filters to reduce the potential α-energy due to radon daughters in the cabs of mining vehicles

International Nuclear Information System (INIS)

Zettwoog, P.; Duport, P.; Campbell, F.E.; Caplan, H.S.

1982-01-01

This paper presents a theoretical analysis of the performance of filters for use in ventilation systems and describes an experiment performed in an inactive stope in an operating uranium mine in France. A series of truck engine air filters were used, designed to remove dust in the tens of microns range with an efficiency of about 5-20. They were chosen because they were designed from the outset to operate under the conditions of shock and vibration likely to be encountered in a mine. It was concluded that the use of the Liebherr filter will reduce the working level in the machine cab by a factor of two. (U.K.)

Selection and specification criteria for fills for cut-and-fill mining

Energy Technology Data Exchange (ETDEWEB)

Thomas, E. G.

1980-05-15

Because of significant differences in placement and loading conditions, the ideal fill material for a cut-and-fill operation has different characteristics to those for a fill for a filled open stoping operation. The differing requirements of the two mining operations must be understood and accounted for in establishing fill selection and specification criteria. Within the paper, aspects of the particular requirements of cut-and-fill mining are analyzed and related to the specific fill tests and properties required. Emphasis is placed upon the role of fill in ground support, though this cannot be isolated from overall fill performance. Where appropriate, test data are introduced and areas requiring continuing research highlighted.

Taoshan uranium ore fields in situ blasting heap leaching rate influence factors to investigate

International Nuclear Information System (INIS)

Xie Wangnan; Dong Chunming

2014-01-01

Taoshan ore field ore in situ blasting heap leaching out build industrial test and production process, stope leaching rate and leaching cycle is large than that, after analysis, blasting method and cloth liquid way is to affect leaching rate and leaching cycle of the main factors. This paper holds that as far as possible using stratified deep hole blasting of squeezing up ways to reduce the building pile of in-situ leaching ore block rate; Adopting effective cloth tube way, increase the leaching agent and ore contact comprehensive; Introduction of bacterial leaching, and other means to improve leaching rate, shorten production cycle, etc to solve it. (authors)

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

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)

Silica exposure and silicosis among Ontario hardrock miners: II. Exposure estimates.

Science.gov (United States)

Verma, D K; Sebestyen, A; Julian, J A; Muir, D C; Schmidt, H; Bernholz, C D; Shannon, H S

1989-01-01

An epidemiological investigation was carried out to determine the relationship between silicosis in hardrock miners in Ontario and cumulative exposure to silica (free crystalline silica--alpha quartz) dust. This second report describes a side-by-side air-sampling program used to derive a konimeter/gravimetric silica conversion curve. A total of 2,360 filter samples and 90,000 konimeter samples were taken over 2 years in two mines representing the ore types gold and uranium, both in existing conditions as well as in an experimental stope in which dry drilling was used to simulate the high dust conditions of the past. The method of calculating cumulative respirable silica exposure indices for each miner is reported.

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...

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 layout 149 5.4 Three dimensional analyses of gully layouts 152 5.4.1 Description of three – dimensional model geometries 152 5.4.2 Single step FLAC3D models 154 5.4.2.1 Analysis method 154 5.4.2.2 General comparison of ASG versus heading cases 154 5.4... ON UNDERGROUND INSPECTIONS 72 4.1 Introduction 72 4.2 Rating of gully conditions 72 4.3 Mining practice compliance with mine standards 72 4.4 Summary of observed gully behaviour resulting from geometry, stress state and ground conditions 80 4.4.1 Shallow...

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.

Mechanism of an increase in roof stability in longwalls during stowing

Energy Technology Data Exchange (ETDEWEB)

Zborshchik, M.P.; Podkopaev, S.V. (Donetskii Politekhnicheskii Institut (Ukraine))

1992-05-01

Presents results of investigations into the stress and strain state of a rock body in the immediate roof and floor in cases of full caving or stowing. Elasto-optical methods were used to compare stress effects that occur when stowing or caving are used. Tangential stresses and roof stability are discussed. It is maintained that full stowing at distances not over 3-3.5 m behind a coal face reduces roof settling to 20-25%. Stress near the working face is reduced by 1.5-1.8 times.

Supporting of mine workings and design of support systems. Madenlerde tahkimat isleri ve tasarmi

Energy Technology Data Exchange (ETDEWEB)

Biron, C; Arioglu, E; (Istanbul Teknik Universitesi, Maden Fakultesi)

1980-01-01

This article deals with elements of elasticity in rocks and examines the engineering properties of rocks. It includes stress distributions around mine openings and deformations of mine openings. Strata control concept in coal mining is explained. Support systems in stone drifts, gateways, shafts and longwalls are discussed; timber supports, steel arches, articulated arches, roof bolting, concrete supports, supports on mechanized faces are detailed. Emphasis is placed upon engineering properties of materials of support systems. The design concepts of mine support systems are described. The objects of the design are expressed with several numerical examples. It concludes with stowing: pneumatic stowing, and hydraulic stowing in metal and coal mining.

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

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

Minerals and energy: major development projects - April 2005 listing

Energy Technology Data Exchange (ETDEWEB)

Ian Haine (and others) [Australian Bureau of Agricultural and Resource Economics (ABARE), Canberra, ACT (Australia)

2005-06-01

The article describes trends in project development and investment in the minerals and energy sector in Australia. It lists competed projects and committed projects. Black coal projects completed during November 2004 to April 2005 were: Dendrobium underground and Mandalong longwall mining expansion projects in New South Wales and development of Curragh North and Eaglefield opencut mine in Queensland. One of the more significant newly listed projects is Macarthur Coal's Queensland Coke Project near Rockhampton. Capital cost and values of projects are included. The full listing of 229 projects is available electronically from ABARE. The list is released around May and November each year. 10 figs., 4 tabs.

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.

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.

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.

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)

On several parameters of mechanized timbering for working faces

Energy Technology Data Exchange (ETDEWEB)

Klorik' yan, S Kh

1979-08-01

Opinion is expressed that the two basic parameters characterizing mechanical timbers, the specific force in ton-forces per square meter of the supported roof surface over the working area and the one-meter length of installed timbering, do not permit selection of the optimum type of timber for a roof of the corresponding class. Experience has demonstrated that the most precise parameter is specific strength of the timber in ton-forces per meter and the determined ratio of the strength of all posts in a section to spacing of the section along the longwall. Also an operating width not exceeding 0.4 meter should serve as a criterion for using timbers on unstable hanging walls. (In Russian)

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)

1997-12-31

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.)

Workability of coal seams in the Upper Silesian Coal Basin

Energy Technology Data Exchange (ETDEWEB)

Sikora, W; Fels, M; Soltysik, K

1978-04-01

This paper presents results of an investigation on workability of coal seams of stratigraphic groups from 100 to 700 in the: Upper Silesian Coal Basin. Analyzed are 2900 petrographic logs taken in the longwall workings and in narrow openings as well as about 9000 individual samples. Workability of coal seams, floors and partings is determined. Workability is described by the indicator f, (according to the Protodyakonov shatter method) and the indicator U, (compression strength of the unshaped test samples). The mean percentage content of indivi dual petrographic groups of coal as well as the mean workability indicator, f, of coals in the stratigraphic groups of coal seams in Upper Silesia are also determined.

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.)

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.

Impulse noise: can hitting a softball harm your hearing?

Science.gov (United States)

Cook, Korrine; Atcherson, Samuel R

2014-01-01

The purpose of this study is to identify whether or not different materials of softball bats (wooden, aluminum, and composite) are a potential risk harm to hearing when batting players strike a 12'' core .40 softball during slow, underhand pitch typical of recreational games. Peak sound pressure level measurements and spectral analyses were conducted for three controlled softball pitches to a batting participant using each of the different bat materials in an unused outdoor playing field with regulation distances between the pitcher's mound and batter's box. The results revealed that highest recorded peak sound pressure level was recorded from the aluminum (124.6 dBC) bat followed by the composite (121.2 dBC) and wooden (120.0 dBC) bats. Spectral analysis revealed composite and wooden bats with similar broadly distributed amplitude-frequency response. The aluminum bat also produced a broadly distributed amplitude-frequency response, but there were also two very distinct peaks at around 1700 Hz and 2260 Hz above the noise floor that produced its ringing (or ping) sound after being struck. Impulse (transient) sounds less than 140 dBC may permit multiple exposures, and softball bats used in a recreational slow pitch may pose little to no risk to hearing.

Controlled blasting experiments in a small drift at the CANMET experimental mine

Energy Technology Data Exchange (ETDEWEB)

Lizotte, Y.C.

1994-03-01

Experiments on controlled blasting conducted at the CANMET Experimental Mine to develop suitable controlled blasting techniques for small development headings are described. The methods selected for study must maintain the drill-blast-muck cycle achieved each work shift. The experiments also examine blast damage mechanisms to formulate criteria for dilution minimization with blast designs in stopes. The drift faces are 2.4 m square, with 34 to 43 holes drilled 2.4 m deep. Cartridged water gels, emulsions, and semi-gelatin dynamite were used in the cuts and as primers, ANFO as the main explosive, and semi- gelatin dynamite in 19 mm diameter cartridges was used in perimeter holes. The results of the first set of experiments show the efficiency of controlled blasting techniques to reduce blast damage. 60 refs., 71 figs., 9 tabs.

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.

The state of hydraulic mining in China and suggestions for future development

Energy Technology Data Exchange (ETDEWEB)

Anon, A.

1996-11-01

This paper discusses the state of development of hydraulic mining technology in China. The paper conceives that the seam conditions most suitable for hydraulic mining are: geologic faults with many cuts, inclined or gradually inclined thick and very thick seams with stable or moderately stable roofs, where longwall mining cannot be employed or pushed far; inclined or steeply inclined strata of inclination angle above 30{degree} with moderately stable roof, where the roof is stable or moderately stable, the inclination angle is greater than 7{degree}, with irregular production pattern and great variation in the seam thickness, or medium to thick coal seam of relatively more geologic damages and poor stability. Some suggestions are proposed for the future development of hydraulic mining.

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

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)

Potential of breccia pipes in the Mohawk Canyon Area, Hualapai Indian Reservation, Arizona

International Nuclear Information System (INIS)

Wenrich, K.J.; Billingsley, G.H.; Van Gosen, B.S.

1990-01-01

The Hualapai Indian Reservation is on the southwestern corner of the Colorado Plateau in northern Arizona. Hundreds of solution-collapse breccia pipes crop out in the canyons and on the plateaus of northern Arizona. The pipes originated in the Mississippian Redwall Limestone and stoped their way upward through the upper Paleozoic strata, locally extending into the Triassic Moenkopi and Chinle Formations. The occurrence of high-grade U ore, associated with potentially economic concentrations of Cu, Ag, Pb, Zn, V, Co, and Ni in some of these pipes, has stimulated mining activity in northern Arizona despite the depressed market for most of these metals. Two breccia pipes, 241, and 242, have significant mineralized rock exposed on the Esplanade erosion surface; unfortunately, their economic potential is questionable because of their inaccessibility at the bottom of Mohawk Canyon. All warrant further exploration

The development of an ore reserve methodology for the Olympic Dam copper-uranium-gold deposit

International Nuclear Information System (INIS)

Scott, I.R.

1987-01-01

At the Olympic Dam copper-uranium-gold deposit in South Australia, evolution in the understanding of the controls on mineralisation coupled with the changing demands of the project have led to changes in the approach to reserve estimation. The project has moved into a phase where detailed stope mining reserves are now required as distinct from global ore reserves. To enable the selective manipulation of geological and assay information and its characterisation, a relational database has been developed. For reserve calculations themselves, initial computations were based on a system derived from that used for the Kambalda nickel orebodies. The Olympic Dam system differed mainly in the use of statistical analyses in the estimation of grade instead of the previous polygonal area of influence weighting method. Three dimensional weighting techniques are now being used for local reserve estimates

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

Comparison of Methane Control Methods in Polish and Vietnamese Coal Mines

Directory of Open Access Journals (Sweden)

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

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...

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.

Design and operation of AFC ramp plates for track clearance on longwall faces

Energy Technology Data Exchange (ETDEWEB)

Shaw, I R

1975-10-01

A study of the use of AFC ramp plates carried out in the University of Newcastle upon Tyne is reported. A 1/4-scale ramp plate test rig was designed and the effects of pushing force, ramp plate toe angle, track width and other factors were studied.

Barriers to the future

Energy Technology Data Exchange (ETDEWEB)

Massey, C T

1986-09-01

Opportunities for the British coal industry seem vast yet there are still barriers to progress. Seven areas are identified and discussed: mining mobility (for example, longwall mining systems are rigid and inflexible compared with American stall and pillar working); mine structure (many mines are more suitable to pit ponies than to large pieces of equipment); financial barriers (Government requires the industry to break even in 1987/88); personnel barriers (less specialization, better use of skills); safety barriers (increased use of remote control, ergonomics and robotics to protect workers); microelectronic management (nationalization has cushioned management from the market place; there is a need for a more multidisciplinary approach to the industry); and legal barriers (most legislation in the past has been in response to accidents; legislation external to the industry but affecting it is more fundamental).

Improvements in seismic event locations in a deep western U.S. coal mine using tomographic velocity models and an evolutionary search algorithm

Energy Technology Data Exchange (ETDEWEB)

Adam Lurka; Peter Swanson [Central Mining Institute, Katowice (Poland)

2009-09-15

Methods of improving seismic event locations were investigated as part of a research study aimed at reducing ground control safety hazards. Seismic event waveforms collected with a 23-station three-dimensional sensor array during longwall coal mining provide the data set used in the analyses. A spatially variable seismic velocity model is constructed using seismic event sources in a passive tomographic method. The resulting three-dimensional velocity model is used to relocate seismic event positions. An evolutionary optimization algorithm is implemented and used in both the velocity model development and in seeking improved event location solutions. Results obtained using the different velocity models are compared. The combination of the tomographic velocity model development and evolutionary search algorithm provides improvement to the event locations. 13 refs., 5 figs., 4 tabs.

Interrater reliability assessment using the Test of Gross Motor Development-2.

Science.gov (United States)

Barnett, Lisa M; Minto, Christine; Lander, Natalie; Hardy, Louise L

2014-11-01

The aim was to examine interrater reliability of the object control subtest from the Test of Gross Motor Development-2 by live observation in a school field setting. Reliability Study--cross sectional. Raters were rated on their ability to agree on (1) the raw total for the six object control skills; (2) each skill performance and (3) the skill components. Agreement for the object control subtest and the individual skills was assessed by an intraclass correlation (ICC) and a kappa statistic assessed for skill component agreement. A total of 37 children (65% girls) aged 4-8 years (M = 6.2, SD = 0.8) were assessed in six skills by two raters; equating to 222 skill tests. Interrater reliability was excellent for the object control subset (ICC = 0.93), and for individual skills, highest for the dribble (ICC = 0.94) followed by strike (ICC = 0.85), overhand throw (ICC = 0.84), underhand roll (ICC = 0.82), kick (ICC = 0.80) and the catch (ICC = 0.71). The strike and the throw had more components with less agreement. Even though the overall subtest score and individual skill agreement was good, some skill components had lower agreement, suggesting these may be more problematic to assess. This may mean some skill components need to be specified differently in order to improve component reliability. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Impulse Noise: Can Hitting a Softball Harm Your Hearing?

Directory of Open Access Journals (Sweden)

Korrine Cook

2014-01-01

Full Text Available The purpose of this study is to identify whether or not different materials of softball bats (wooden, aluminum, and composite are a potential risk harm to hearing when batting players strike a 12′′ core .40 softball during slow, underhand pitch typical of recreational games. Peak sound pressure level measurements and spectral analyses were conducted for three controlled softball pitches to a batting participant using each of the different bat materials in an unused outdoor playing field with regulation distances between the pitcher’s mound and batter’s box. The results revealed that highest recorded peak sound pressure level was recorded from the aluminum (124.6 dBC bat followed by the composite (121.2 dBC and wooden (120.0 dBC bats. Spectral analysis revealed composite and wooden bats with similar broadly distributed amplitude-frequency response. The aluminum bat also produced a broadly distributed amplitude-frequency response, but there were also two very distinct peaks at around 1700 Hz and 2260 Hz above the noise floor that produced its ringing (or ping sound after being struck. Impulse (transient sounds less than 140 dBC may permit multiple exposures, and softball bats used in a recreational slow pitch may pose little to no risk to hearing.

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

Supplementary recovery of uranium by in-situ leaching at the Brugeaud deposit (Limousin, France)

International Nuclear Information System (INIS)

Lyaudet, G.

1980-01-01

The actual mining operations at the Brugeaud Deposit (West Brugeaud and East Brugeaud) were followed by supplementary recoveries of uranium by means of in-situ leaching. There were a number of factors which favoured consideration of these operations: the amounts of uranium present at the edge of the stoped areas; the underground mining infrastructure, which did not require supplementary operations for the recovery of solutions; the nature of the rock, which presented a dense network of fractures and micro-fractures conducive to impregnation by the acid solutions; and the immediate proximity of a concentration plant. The amount of uranium recovered by in-situ leaching is close to 200 t. This production is approximately nine per cent of all the uranium extracted from the deposit. The cost of the metal obtained in this way was always less than FF 100 (FF of 1978) per kilogram of uranium. (author)

ISP Descriptions of Four Military Computer Architectures

Science.gov (United States)

1978-04-01

SOn Tot) ENDI IENC JEP JOPi. I JUMP ON 000 PARITY BE GIN OP TD I I GLTO NEXT T7A - ’rM AND TAI NEXT PARITY •TEXT I CEtCk PARITY (TI TO .> P * so Tot...WIo10lc6iO1 I NEXT NUIAO I STOPE (T019) IN PCcWI&ATW? (As) I NEXT EN~i ILNO HSC? UvP 7,1!sr Iwx7inr-non 1.tt-1 I tD 3-7,b-?S 11806 wiCI ~utJ-I8O Page 91...8217 ((C t4,3 YPMiNPE~ SF * d.ttýp(iiIZ) L53 MAWR.u, 1, NO I COGl. - IPIOI GC..’r ".Ced half r"o.’iv - I P411 11.Pi-4i * M,’r~pCINUCS, P’PIOWfu-.",,I)Q2𔃺i

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.

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

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...

Hazard control at the workplace; Maitriser le risque au poste de travail

Energy Technology Data Exchange (ETDEWEB)

NONE

1994-12-31

A total of 78 papers were presented at the symposium in four sections: a general section entitled risk analysis and appropriate prevention strategies, and three workshops entitled: measuring atmospheric pollution at the workplace - biological monitoring; personal protective equipment: effectiveness and ergonomics; and changing technologies and human reliability in production systems. Opening addresses, reports on each workshop, and a summary of the round table and discussions, and closing remarks are included in the proceedings. Two papers are of particular relevance to the coal industry. They are entitled: `Using computer simulation to analyze risk in longwall mine emergency evacuations` by A.F. Glowacki of the US Bureau of Mines, Pittsburgh, PA, USA and `Determination of the urinary excretion of metabolites of polycyclic aromatic hydrocarbons by coke plant workers` by G. Grimmer, K.-W. Naujack and G. Dettbarn of The Biochemisches Institut fuer Unweltcarcinogene, Grosshansdorf, Germany.

The global supplier - myth or reality?

Energy Technology Data Exchange (ETDEWEB)

Crawshaw, S A.M. [Long-Airdox Ltd., Ilkeston (United Kingdom)

2002-02-01

Coal remains a key feature of the world's energy and steel markets and coal mining is a global industry. Suppliers of equipment to the coal-mining industry have seen traditional markets almost disappear and new markets emerge. Suppliers need to work closely with customers, sometimes in remote areas developing long-term partnerships and continually improving the product to their mutual benefit. An attempt to explain how global changes to the underground coal industry have influenced the supply of coal-mining equipment is illustrated by recent developments in the Long-Airdox group. An example is given of how the group worked with the Cayirhan Mine in Turkey supplying cast armoured face conveyors for longwall mining. The paper was presented at a meeting of the Nottinghamshire Branch of the Institution of Mining and Metallurgy on 3 June 1998 in Nottinghamshire, UK. 1 fig.

Coal industry - memoranda

Energy Technology Data Exchange (ETDEWEB)

1986-01-01

This paper contains 41 memoranda submitted to the UK House of Commons Energy Committee containing views on the UK coal industry and responses to questions from the Select Committee. The following organizations are represented: Department of Energy; National Coal Board; APEX; BACM; NACODS; NUM; UDM; TUC; CEGB; Electricity Council; Northern Ireland Electricity Service; SSEB; British Gas Corporation; BP; Conoco (UK) Ltd.; Costain Mining Ltd.; Shell UK Ltd.; BSC; ICI; Boots; CBI; PSA; Solid Fuel Advisory Service; Domestic Coal Consumers Council; Associated Heat Services; Association of Shell Boilermakers; Babcock Power Ltd.; GEC; Foster Wheeler Power Products; ABMEC; British Longwall Mining Association; Federation of Civil Engineering Contractors; Federation of Small Mines of Great Britain; Chamber of Coal Traders; Coalfield Communities Campaign; Nottinghamshire County Council; Federation of Self-Employed and Small Businesses; the Colombian, Belgian and Netherlands Embassies; and Plaid Cymru.

Internet technologies in the mining industry. Towards unattended mining systems

Energy Technology Data Exchange (ETDEWEB)

Krzykawski, Michal [FAMUR Group, Katowice (Poland)

2009-08-27

Global suppliers of longwall systems focus mainly on maximising the efficiency of the equipment they manufacture. Given the fact that, since 2004, coal demand on world markets has been constantly on the increase, even during an economic downturn, this endeavour seems fully justified. However, it should be remembered that maximum efficiency must be accompanied by maximum safety of all underground operations. This statement is based on the belief that the mining industry, which exploits increasingly deep and dangerous coal beds, faces the necessity to implement comprehensive IT systems for managing all mining processes and, in the near future, to use unmanned mining systems, fully controllable from the mine surface. The computerisation of mines is an indispensable element of the development of the world mining industry, a belief which has been put into practice with e-mine, developed by the FAMUR Group. (orig.)

Experimental investigations of the stability of winning equipment and of scraper-chain conveyors

Energy Technology Data Exchange (ETDEWEB)

Henkel, E H [Bergbau-Forschung G.m.b.H., Essen (Germany, F.R.). Versuchsfeld fuer Gewinnungs- und Strebfoerdertechnik; Ahrens, K; Dembeck, R [Berbau-Forschung G.m.b.H., Essen (Germany, F.R.)

1979-06-01

Extensive experiments have been carried out in order to find out about the correlation between strength and time behaviour of displacement, holding, and staying forces. The findings have shown that displacement forces depend on chain slack forces due to the drives. The maximum values of slack forces do not occur together, so that their sum does not act as total force. One finding was that when overload prevention devices are used, these do not respond simultaneously. Therefore, only the shear bolt fracture force of one drive can have a displaying effect. Apart from frictional forces, position-stabilizing holding forces were effects of mass acceleration and elastic forces as well as the holding forces of the longwall face. In addition to these experiments, a mathematical description of blocking and staying processes was elaborated at the institute of mining scineces of Aachen technical university.

Longwall top coal caving (LTCC) mining technologies with roof softening by hydraulic fracturing method

Science.gov (United States)

Klishin, V.; Nikitenko, S.; Opruk, G.

2018-05-01

The paper discusses advanced top coal caving technologies for thick coal seams and addresses some issues of incomplete coal extraction, which can result in the environmental damage, landscape change, air and water pollution and endogenous fires. The authors put forward a fundamentally new, having no equivalent and ecology-friendly method to difficult-to-cave roof coal – directional hydraulic fracturing and nonexplosive disintegration.

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.

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)

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

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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.

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 skill components (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.

BING-NEEL SYNDROME: ILLUSTRATIVE CASES AND COMPREHENSIVE REVIEW OF THE LITERATURE

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Marzia Varettoni

2017-10-01

Full Text Available The Bing-Neel syndrome is a rare neurological complication of Waldenström’s Macroglobulinemia which results from a direct involvement of central nervous system by malignant lymphoplasmacytic cells. The clinical suspicion of Bing-Neel syndrome may be difficult because neurologic symptoms are heterogeneous, non specific and sometimes underhand. A definitive diagnosis of Bing-Neel syndrome can be confidently made using brain and spinal cord magnetic resonance imaging as well as histopathology and/or cerebrospinal fluid analysis to confirm the neoplastic infiltration of central nervous system. The detection in the cerebrospinal fluid of patients with Bing-Neel syndrome of the MYD88 (L265P somatic mutation, which is highly recurrent in Waldenström’s Macroglobulinemia, revealed useful for the diagnosis and monitoring of central nervous system involvement. Despite recommendations recently published, there is still no clear consensus on treatment of Bing-Neel syndrome, which includes systemic immunochemotherapy, intrathecal chemotherapy and brain irradiation as possible options. Ibrutinib, a Bruton kinase inhibitor highly active in patients with Waldenström’s Macroglobulinemia, has been recently added to the therapeutic armamentarium of Bing-Neel syndrome due to its ability to pass the blood-brain barrier. However, prospective clinical trials are eagerly awaited with the aim to define the optimal treatment strategy.  Here we describe four illustrative cases of Bing-Neel syndrome diagnosed and treated at our Institution and review the literature on this topic.

End-state comfort trumps handedness in object manipulation.

Science.gov (United States)

Coelho, Chase J; Studenka, Breanna E; Rosenbaum, David A

2014-04-01

A goal of research on human perception and performance is to explore the relative importance of constraints shaping action selection. The present study concerned the relative importance of two constraints that have not been directly contrasted: (1) the tendency to grasp objects in ways that afford comfortable or easy-to-control final postures; and (2) the tendency to grasp objects with the dominant rather than the nondominant hand. We asked participants to reach out and grasp a horizontal rod whose left or right end was to be placed into a target after a 90° rotation. In one condition, we told participants which hand to use and let them choose an overhand or underhand initial grasp. In another condition, we told participants which grasp to use and let them choose either hand. Participants sacrificed hand preference to perform the task in a way that ensured a comfortable or easy to control thumb-up posture at the time of object placement, indicating that comfort trumped handedness. A second experiment confirmed that comfort was indeed higher for thumb-down postures than thumb-up postures. A third experiment confirmed that the choice data could be linked to objective performance differences. The results point to the importance of identifying constraint weightings for action selection and support an account of hand selection that ascribes hand preference to sensitivity to performance differences. The results do not support the hypothesis that hand preference simply reflects a bias to use the dominant hand.

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.

Installation of a digital, wireless, strong-motion network for monitoring seismic activity in a western Colorado coal mining region

Energy Technology Data Exchange (ETDEWEB)

Peter Swanson; Collin Stewart; Wendell Koontz [NIOSH, Spokane, WA (USA). Spokane Research Laboratory

2007-01-15

A seismic monitoring network has recently been installed in the North Fork Valley coal mining region of western Colorado as part of a NIOSH mine safety technology transfer project with two longwall coal mine operators. Data recorded with this network will be used to characterize mining related and natural seismic activity in the vicinity of the mines and examine potential hazards due to ground shaking near critical structures such as impoundment dams, reservoirs, and steep slopes. Ten triaxial strong-motion accelerometers have been installed on the surface to form the core of a network that covers approximately 250 square kilometers (100 sq. miles) of rugged canyon-mesa terrain. Spread-spectrum radio networks are used to telemeter continuous streams of seismic waveform data to a central location where they are converted to IP data streams and ported to the Internet for processing, archiving, and analysis. 4 refs.

Determination of Abutment Pressure in Coal Mines with Extremely Thick Alluvium Stratum: A Typical Kind of Rockburst Mines in China

Science.gov (United States)

Zhu, Sitao; Feng, Yu; Jiang, Fuxing

2016-05-01

This paper investigates the abutment pressure distribution in coal mines with extremely thick alluvium stratum (ETAS), which is a typical kind of mines encountering frequent intense rockbursts in China. This occurs due to poor understanding to abutment pressure distribution pattern and the consequent inappropriate mine design. In this study, a theoretical computational model of abutment pressure for ETAS longwall panels is proposed based on the analysis of load transfer mechanisms of key stratum (KS) and ETAS. The model was applied to determine the abutment pressure distribution of LW2302S in Xinjulong Coal Mine; the results of stress and microseismic monitoring verified the rationality of this model. The calculated abutment pressure of LW2302S was also used in the terminal mining line design of LW2301N for rockburst prevention, successfully protecting the main roadway from the adverse influence of the abutment pressure.

Features of development process displacement of earth’s surface when dredging coal in Eastern Donbas

Science.gov (United States)

Posylniy, Yu V.; Versilov, S. O.; Shurygin, D. N.; Kalinchenko, V. M.

2017-10-01

The results of studies of the process of the earth’s surface displacement due to the influence of the adjacent longwalls are presented. It is established that the actual distributions of soil subsidence in the fall and revolt of the reservoir with the same boundary settlement processes differ both from each other and by the distribution of subsidence, recommended by the rules of structures protection. The application of the new boundary criteria - the relative subsidence of 0.03 - allows one to go from two distributions to one distribution, which is also different from the sedimentation distribution of protection rules. The use of a new geometrical element - a virtual point of the mould - allows one to transform the actual distribution of subsidence in the model distribution of rules of constructions protection. When transforming the curves of subsidence, the boundary points vary and, consequently, the boundary corners do.

Results of testing the frontal AK-3 extraction unit

Energy Technology Data Exchange (ETDEWEB)

Yakovlev, N I; Dolinskii, A M; Kolesnikov, M A

1978-10-01

From August to November 1970, on site testing of a protype frontal AK excavating rig developed by Giprouglemesh for use on gentle sloping seams was conducted in the Novaya mine of the Kuzbass Ugol Consolidated. The AK-3 consists of a cutting assembly in the form of a ring frontal slicer with two drives, hydraulic operated sectionalized support timbers of the enclosed lift type, conjugated timbering with ventilation and conveyor shafts, personnel elevator and hydraulic and electrical ancillary equipment. The production capacity of the rig in longwalls is 2.2 times greater on the average than by using drillhole blasting methods. Tests demonstrated that the main advantage of the Ak-3 was the single operation, continuous flow mode of coal extraction and remote frontal movement of timber sections, which ensured high capacity loading at the face and the capability of automating all procedures and eliminating all workers from the extraction face.

Landslides in the area of the Jastrzebie town protective pillar

Energy Technology Data Exchange (ETDEWEB)

Rybicki, S

1986-01-01

Analyzes 76 landslides in the area of the safety pillar of Jastrzebie in the Rybnik coal region. Of 76 landslides 60% fell on natural slopes with an angle of 25-50 degrees, 22% on natural slopes with a 5-25 degree angle, 10% on man-made cuts and 8% on embankments. About 78% of the landslides was associated with water bearing layers. Of the 76 landslides 32 were situated in the safety pillar and 44 close to the pillar. Thirty-three landslides were closely associated with underground mining: 30 landslides were caused by longwall mining (landslide position was related to working face position), a further 3 were associated with mining in general. Statistical data on landslides associated with underground coal mining are analyzed: landslide area, angle of slope inclination, height, landslide range, water conditions, types of soils, types of mining areas classified according to effects of mining damage. 8 refs.

A jewel in the desert: BHP Billiton's San Juan underground mine

Energy Technology Data Exchange (ETDEWEB)

Buchsbaum, L.

2007-12-15

The Navajo Nation is America's largest native American tribe by population and acreage, and is blessed with large tracks of good coal deposits. BHP Billiton's New Mexico Coal Co. is the largest in the Navajo regeneration area. The holdings comprise the San Juan underground mine, the La Plata surface mine, now in reclamation, and the expanding Navajo surface mine. The article recounts the recent history of the mines. It stresses the emphasis on sensitivity to and helping to sustain tribal culture, and also on safety. San Juan's longwall system is unique to the nation. It started up as an automated system from the outset. Problems caused by hydrogen sulfide are being tackled. San Juan has a bleederless ventilation system to minimise the risk of spontaneous combustion of methane and the atmospheric conditions in the mine are heavily monitored, especially within the gob areas. 3 photos.

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 of depth below surface Figure 2.5 Contributing factors to 89 accident incidents as a function of reef Figure 2.6 Relative proportion of key factors contributing to anomalous conditions on the VCR, as determined from 28 incidents Figure 3.1 Location... to correctly recognise and address problems. The project considers gold mines in the Witwatersrand basin and platinum mines in the Bushveld Igneous Complex, at all depths from near surface to in excess of 3500 m, on a range of economically important reefs...

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

Geologic Mapping in Nogal Peak Quadrangle: Geochemistry, Intrusive Relations and Mineralization in the Sierra Blanca Igneous Complex, New Mexico

Science.gov (United States)

Goff, F.; Kelley, S. A.; Lawrence, J. R.; Cikowski, C. T.; Krier, D. J.; Goff, C. J.; McLemore, V. T.

2011-12-01

Nogal Peak quadrangle is located in the northern Sierra Blanca Igneous Complex (SBIC) and contains most of the White Mountain Wilderness (geologic map is available at http://geoinfo.nmt.edu/publications/maps/geologic/ofgm/details.cfml?Volume=134). The geology of the quad consists of a late Eocene to Oligocene volcanic pile (Sierra Blanca Volcanics, mostly alkali basalt to trachyte) intruded by a multitude of dikes, plugs and three stocks: Rialto, 31.4 Ma (mostly syenite), Three Rivers, ca. 29 to 27 Ma (quartz syenite intruded by subordinate alkali granite), and Bonito Lake, 26.6 Ma (mostly monzonite). Three Rivers stock is partially surrounded by alkali rhyolites that geochemically resemble the alkali granites. The circular shape of the stock and surrounding rhyolites suggests they form the root of a probable caldera. SBIC rocks have compositions typical of those found within the Rocky Mountain alkaline belt and those associated with continental rift zone magmatism. Because the volcanic host rocks are deeply eroded, intrusive relations with the stocks are well exposed. Most contacts at stock margins are near vertical. Roof pendants are common near some contacts and stoped blocks up to 700 m long are found within the Three Rivers stock. Contacts, pendants and stoped blocks generally display some combination of hornfelsing, brecciation, fracturing, faulting and mineralization. Sierra Blanca Volcanics display hydrothermal alteration increasing from argillic in the NW sector of the quad to high-temperature porpylitic near stock margins. Retrograde phyllic alteration occurs within breccia pipes and portions of the stocks. Mineral deposits consist of four types: Placer Au, fissure veins (mostly Ag-Pb-Zn±Au), breccia pipes (Au-Mo-Cu), and porphyry Mo-Cu. A singular pipe on the SW margin of Bonito Lake stock contains sapphire-lazulite-alunite. Although Au has been intermittently mined in the quad since 1865, best production of Au originated around the turn of the last

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

2017-01-01

ABSTRACT Background: 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. Methods: 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

ANALYSIS OF THE POSSIBILITY OF INTEGRATING A MINING RIGHT-ANGLE PLANETARY GEARBOX WITH TECHNICAL DIAGNOSTICS SYSTEMS

Directory of Open Access Journals (Sweden)

Andrzej WIECZOREK

2016-12-01

Full Text Available A key factor enabling the achievement of the required capacity by longwall mining systems is to obtain a satisfactory service life for individual components of such systems. Such components include right-angle planetary gearboxes for armoured face conveyors. An increase in the service life of such equipment can be achieved by ensuring adequacy in terms of design, materials and organization. As a part of organizational changes, the use of individual diagnostics systems may have the greatest impact on the service life of mining gearboxes; however, their widespread implementation is limited by economic and operational barriers. This paper presents an analysis of the possibility of integrating mining gearboxes with electronic systems of technical diagnostics, as well as expanding the scope of the technical condition monitoring by the machines operating together with these gearboxes. As a result of the calculation and design work performed, it has been demonstrated that it is possible to integrate technical diagnostics systems with advanced data transmission capabilities inside gearboxes.

Planning design of Ukrainian mines by the means of numerical calculations

Energy Technology Data Exchange (ETDEWEB)

Ruppel, Ulrich; Scior, Carsten [DMT GmbH und Co. KG (DMT), Essen (Germany). Rock Mechanic Dept.

2008-08-21

Using a mine in the Ukraine as an example it is shown how the DMT performs rock mechanical and support planning or roadways in hard coal mines worldwide. Therefore it is necessary to analyse existing measurements and operating experience within a few days as well as organising further surveys on site on short notice. Based on these results the numerical models are calibrated. Using the numerical simulation technology it is possible for DMT to quantify and analyse the rock mechanical impact of different support systems within a short time. Finally the results of the numerical calculations are set in comparison in a rating matrix. Besides making a decision on implementing new roadway and support systems with the objective to use the roadways up to the second longwall panel, the rating matrix is also used for analysing the optimization potentials of existing support systems. This allows the recommendations to immediate improvement of the strata control in the miner's roadways. (orig.)

Coal mine subsidence: effects of mitigation on crop yields. [USA - Illinois

Energy Technology Data Exchange (ETDEWEB)

Darmody, R.G.; Hetzler, R.T.; Simmons, F.W. (Illinois Univ., Urbana, IL (USA). Dept. of Agronomy)

1992-01-01

Subsidence from longwall underground coal mining adversely impacts agricultural land by creating wet or ponded areas. While most subsided areas show little impact, some localized places, usually less than 1.5 ha in size, may experience total crop failure. Coal companies mitigate subsidence damaged cropland by installing drainage waterways or by adding fill material to raise the grade. The objective of this study was to test the effectiveness of mitigation in restoring corn and soybean yields to pre-mined levels. Fourteen sites in southern Illinois were selected for study. Corn ([ital Zea mays] L.) and soybean ([ital Glycine max] L.) yields from mitigated and nearby undisturbed areas were compared for four years. Results varied due to differing weather and site conditions. Mean corn yields overall, however were significantly ([alpha]0.05) lower on mitigated areas. There was no significant difference in overall mean soybean yields. Soil fertility levels were similar and did not account for yield differences. 14 refs., 1 fig., 7 tabs.

Coal mine subsidence: effects of mitigation on crop yields

International Nuclear Information System (INIS)

Darmody, R.G.; Hetzler, R.T.; Simmons, F.W.

1992-01-01

Subsidence from longwall underground coal mining adversely impacts agricultural land by creating wet or ponded areas. While most subsided areas show little impact, some localized places, usually less than 1.5 ha in size, may experience total crop failure. Coal companies mitigate subsidence damaged cropland by installing drainage waterways or by adding fill material to raise the grade. The objective of this study was to test the effectiveness of mitigation in restoring corn and soybean yields to pre-mined levels. Fourteen sites in southern Illinois were selected for study. Corn (Zea mays L.) and soybean (Glycine max L.) yields from mitigated and nearby undisturbed areas were compared for four years. Results varied due to differing weather and site conditions. Mean corn yields overall, however were significantly (α0.05) lower on mitigated areas. There was no significant difference in overall mean soybean yields. Soil fertility levels were similar and did not account for yield differences. 14 refs., 1 fig., 7 tabs

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.

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.

The upper pennsylvanian pittsburgh coal bed: Resources and mine models

Science.gov (United States)

Watson, W.D.; Ruppert, L.F.; Tewalt, S.J.; Bragg, L.J.

2001-01-01

The U.S. Geological Survey recently completed a digital coal resource assessment model of the Upper Pennsylvanian Pittsburgh coal bed, which indicates that after subtracting minedout coal, 16 billion short tons (14 billion tonnes) remain of the original 34 billion short tons (31 billion tonnes) of coal. When technical, environmental, and social restrictions are applied to the remaining Pittsburgh coal model, only 12 billion short tons (11 billion tonnes) are available for mining. Our assessment models estimate that up to 0.61 billion short tons (0.55 billion tonnes), 2.7 billion short tons (2.4 billion tonnes), and 8.5 billion short tons (7.7 billion tonnes) could be available for surface mining, continuous mining, and longwall mining, respectively. This analysis is an example of a second-generation regional coal availability study designed to model recoverability characteristics for all the major coal beds in the United States. ?? 2001 International Association for Mathematical Geology.

Economic aspects of comprehensive mechanization of mining operations. [Poland

Energy Technology Data Exchange (ETDEWEB)

Zemla, F

1978-02-01

The development of mining equipment for longwall mining and effects of mechanization of mining operations on labor productivity and output of underground coal mines in Poland from 1950 to 1976 are discussed. Mining equipment used from 1950 to 1960 (cutters, steel or timber supports, chain conveyors, drilling and blasting), from 1960 to 1970 (cutter loaders, chain conveyors and steel supports), from 1970 to 1976 (shearer loaders, chain conveyors and powered or shield supports) is analyzed. Coal output of faces mined by mechanized equipment increased from 9.7% in 1950 to 63.1% in 1969 and to 87.6% of total coal output in 1976. The total coal output of underground coal mines increased from 99.1 Mt in 1959 to 125.0 Mt in 1969 and 179.3 Mt in 1976. Labor productivity per miner increased from 1.561 t/d in 1959 to 2.529 t/d in 1969 and to 3.433 t/d in 1976.

Expediency of using pneumatic balloons at the junction of a working face and gate roads

Energy Technology Data Exchange (ETDEWEB)

Kolokolov, O V; Litvinov, Yu G; Ozerova, A S

1983-02-01

The paper discusses strata control at longwall faces in thin coal seams. Use of pneumatic balloons instead of timber cribbing at the junction of the face and ventilation road is evaluated. The seam is 0.68 m thick at a depth of 980 m and has gradients from 60 to 63 degrees. The face mined by the Poisk coal cutter is 126 m long. The ventilation road is protected by strips of stowing. Use of pneumatic balloons with an initial pressure of 150 kN instead of timber cribbing with an initial pressure of 30 kN reduces convergence of the roof and the floor at the working face by 39%. Damage to hydraulic props at the working face caused by roof subsidence decreases by 10 to 15%. Convergence rate (measured in mm/d) decreases by 41%. Use of pneumatic balloons for strata control at working faces in thin coal seams is recommended.

Assessment of risk of accident at work as an indicator of safe behaviour of workers

Energy Technology Data Exchange (ETDEWEB)

Pisiewicz, K

1978-10-01

In 1977 the Psychology and Sociology Research Development Unit of the Central Mining Institute carried out research on the influence of assessment of the accident risk on the safe behaviour of workers. 450 workers employed at the longwall faces in 6 coal mines with various accident rates were questioned. It was found that a low assessment of risk favours hazardous operations, contrary to the principles of work safety, while a high assessment of the risk does not favour hazardous operations. Miners employed in coal mines with high accident rates tend to a low assessment of accident risk (arithmetic mean x 48.54) in comparison to miners from mines with low accident rates (arithmetic mean x 53.68). It was also found that the arithmetic mean of assessment of risks among workers who had had an accident at work is lower (x 50.3) than among workers who had not yet had an accident at work (x 55.32).

Rock burst prevention at steep seam mining

Energy Technology Data Exchange (ETDEWEB)

Efremov, G D

1988-09-01

At steep shield longwalls one method of preventing rock bursts is to avoid sharp angles during working. Stress in coal and rock body that appears when steep seams are worked where rock bursts occur at corners of set-up entries is discussed. The dynamic interaction between gas and rock pressure is assessed. Maintains that in order to avoid rock bursts at these places it is necessary to turn the protruding coal wall by 20-30 degrees towards the coal body to divert the action of shift forces. At the same time the face should also be inclined (by 10-15 degrees) to move the zones of increased stress away from the corner into the coal and rock body. Stress at workings with round cross-sections is 3-4 times lower than at square cross-sections. Recommendations are given that concern shearer loader operation (semi-spherical shape of the face), borehole drilling and water injection. Initial distance of 10-15 m between boreholes is suggested. 3 refs.

GPK helmets protecting from gas and dusts

Energy Technology Data Exchange (ETDEWEB)

Il' inskii, Eh.G.; Kogan, Yu.A.; Mazanenko, V.P.

1983-08-01

The GPK protective helmet with an integrated respirator system protecting a miner's respiratory system and eyes from gases and dusts is described. The system uses compressed air from the mine compressed air system. Air is supplied to the respirator by an elastic rubber pipe to 30 m long. The air cools the miner's head under the helmet and passes between a protective shield and the miner's face protecting eyes and the respiratory system. Air supply ranges from 100 to 150 l/min. The air supplied to the respirator is cleaned by a filter. The GPK system weighs 1.2 kg. The system has been tested under laboratory conditions and in two coal mines under operational conditions at longwall faces and during mine drivage. Tests showed that the GPK guarantees efficient cooling and protection from dust. Design of the GPK helmet with a respirator is shown in two schemes. Technical specifications of the system are given.

Technological possibilities for increasing coarse coal yield in the Staszic mine

Energy Technology Data Exchange (ETDEWEB)

Sikora, W; Major, M

1985-06-01

Experiments carried out in the Staszic underground black coal mine in Upper Silesia showed that there is a correlation of coarse coal yield and yield strength of shield supports used at longwall faces. The faces were equipped with Pioma 25-45, Fazos 15-31 and Fazos 19-32 shield supports, KWB 3RDU shearer loaders and Rybnik chain conveyors. Pressure of oil in water emulsion used in the Pioma 25/45 shield supports was reduced from the recommended 30 MPa to 15 MPa or to 10 MPa. Reducing emulsion pressure (and support yield strength) caused an increase in coarse coal yield. Coarse coal yield was also increased by use of Fazos 19/32 shield supports with reduced yield strength. During the tests coarse coal yield increased 1.68% and 2.65%. Test results are shown in 3 diagrams. Investigations carried out in the Staszic mine in 1983 showed that by optimizing yield strength of shield supports coarse coal yield could be increased 2 to 8%. 6 references.

Advanced face support systems for use in complex mining- geological conditions. Progressivnye tekhnologicheskie skhemy krepleniya ochistnykh zaboev v slozhnykh gorno-geologicheskikh usloviyakh

Energy Technology Data Exchange (ETDEWEB)

Rudnitskii, Yu I; Kuz' menko, N I

1985-01-01

This paper reviews utilization of advanced methods of roof control and face supports in Donbass coal mines involving the application of new technology (metal slide bars, hydraulic props with increased carrying capacity, etc.). Discusses the effect of supporting longwall areas on the stability of roofs and the application of metal roof bars together with single props in an area with unstable roof rock, particularly where the conveyor belts turn, thus achieving reliable roof support at the prop-free-front faces. This replaces chemical strengthening of the rock or the use of packs. Since the modern narrow-web cutter loaders cannot, using present methods of roof support, reduce the unsupported area to less than 8-10 m/sup 2/ and with the probability of rock falls increasing proportionally to the square of the distance between bar ends and the face, it is necessary to use methods which will increase work safety in the changing mining-geological conditions. (10 refs.)

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

THE ADOPTION OF THE ARCGIS SYSTEM TO SUPPORT THE ANALYSES OF THE INFLUENCE OF THE MINING TREMORS ON THE BUILDING OBJECTS

Directory of Open Access Journals (Sweden)

Violetta SOKOŁA-SZEWIOŁA

2016-10-01

Full Text Available Nowadays the mining companies use the Spatial Information System in order to facilitate data management, gathered during the mining activity. For these purposes various kinds of applications and software information are used. They allow for faster and easier data processing. In the paper there are presented the possibilities of using the ArcGIS system to support the tasks performed in the mining industry in the scope of the analysis of the influence of the mining tremors, induced by the longwall exploitation on the facilities construction sited on the surface area. These possibilities are presented by the example of the database developed for the coal mine KWK “Rydułtowy-Anna.” The developed database was created using ArcGIS software for Desktop 10. 1. It contains the values of parameters, specified for its implementation relevant to the analyses of the influence of the mining tremors on the surface structures.

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.

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

Science.gov (United States)

Zask, Avigdor; Barnett, Lisa M; Rose, Lauren; Brooks, Lyndon O; Molyneux, Maxine; Hughes, Denise; Adams, Jillian; Salmon, Jo

2012-10-22

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'. 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. 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). Early childhood settings should implement movement skill interventions and more intensively target girls and object control skills.

Remedios, a bela: beleza, erotismo e poder de morte em Cem anos de solidão

Directory of Open Access Journals (Sweden)

Eline Aguiar Costa

2016-07-01

Full Text Available Remedios, the Beauty, female character in One Hundred Years of Solitude (1967, by Gabriel García Márquez, is a testimony that “small” characters could be as complex as a main character in great works. The narrator’s speech try to convince us that the Beauty have death powers. In this masterpiece by García Márquez, four men who died in different situations have something in common: they have known Remedios. Those deaths are because they have lost their minds for the reason that she is a “deranging woman”. Her smell, her manners and her beauty became these men to be able to do things that brought their deaths. The work, full of rebellious, strong and sexual female characters, shows the Beauty as a character with a new feminine behavior, a new way to be transgressive. Our purpose was introduce her and analyze her by means of bibliographic search, as a erotic, magical and transgressive female character, telling happenings of her life. Therefore, we reached a conclusion that she has all of those characteristics, and the author isn’t sure about if she is innocent or underhanded about lecherous feelings that she causes. Helped us in this article, on theoretical and critique feminist literature field and matters of gender the research by Perrot (2007, Ribeiro (2006, Galvão e Prado Jr. (1979, Badinter (1985 and Imbriaco (2009. On theoretical and critique literature field, our analyzes were based on research by Rodrigues (1988, Vargas Liosa (2007, De La Concha (2007 and Josef (1993.

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 ...........................................................................18 Figure 11. Generic VCR hangingwall............................................................................................19 Figure 12. Resin grouted rebar – tensile loading across a joint (after Stillborg, 1994)................20 Figure 13.... Split Set type SS 39 – tensile loading across a joint (after Stillborg, 1994)................21 Figure 14. Expansion shell anchored rockbolt - tensile loading across a joint (after Stillborg, 1994...

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

OpenAIRE

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 ...

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)

Geological control in computer-based resource estimation

International Nuclear Information System (INIS)

Cram, A.A.

1992-01-01

The economic assessment of mineral deposits potentially involves a number of phases from initial assessment through to detailed orebody evaluation and subsequently to estimation of bench or stope grades in an operational mine. Obviously the nature and quantity of information varies significantly from one extreme to the other. This paper reports on geological interpretation which obviously plays a major part during the early phases of assessment and it logically follows that computerized orebody assessment techniques must be able to effectively utilize this information. Even in an operational mine the importance of geological control varies according to the type of orebody. The method of modelling coal seams is distinctly different from those techniques used for a massive sulphide deposit. For coal seams significant reliance is placed on the correlation of seam intercepts from holes which are widely spaced in relation to the seam (i.e.) orebody) thickness. The use of geological interpretation in this case is justified other experience gained in the past, compared to the cost of reliance only on samples from a very dense drill hole pattern

Mechanical solution of the maximum point of dynamic abutment pressure under deep long-wall working face

Energy Technology Data Exchange (ETDEWEB)

Jiang, F.; Ma, Q. [Shandong University of Science and Technology, Tai' an (China). College of Resource and Environmental Engineering

2002-06-01

The paper studies the dynamic relationship between abutment pressure and overburden collapse precess with advancing of working face. The result shows that the abutment pressure reaches its maximum value when the working face dimension is 1.27 times of the mining depth. This result confirms the statistical result from the strata movement surveys that overburden reaches its full movement stage when extracting dimension reaches 1.2 1.4 times of the mining depth. 12 refs., 2 figs.

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

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 of the support units, the potential benefit of simple mesh straps sandwiched between the tops of adjacent conventional timber elongates and the hangingwall surface above, as a means of linking individual support units and supporting potentially loose blocks...

Structuralistic Analysis of the Poem “The Stone Chat” by Taufeeq Rafat in perspective of Binary Opposition

Directory of Open Access Journals (Sweden)

Bushra Munawar

2016-07-01

Full Text Available The aim of this research study is to apply Structuralism (a Linguistic movement related to scientific study of words as signs as a theoretical framework on the poem “The Stone Chat” by Taufiq Rafat, a prominent Pakistani poet. The study focuses on, presenting Structuralistic analysis (relation between sign and signifier of the selected text, as proposed by the Swiss Structuralist, De Saussure. Besides, this paper particularly is a textual analysis of a Pakistani piece of poetry by application of linguistic concept of binary opposites (paired opposite as proposed by a Linguist Levi-Strauss (a linguist in his book Structuralist Anthropology, (1950. The searching of text for binary oppositions is the targeted endeavor of this study with the focus to analyze how far they are skillfully and contextually positioned in this poem. Hence, the researchers intend to focus on the antithetical forces and binary ideas present in the text. The close textual analysis of the poem is aimed at in this context, since The Stone Chat has antithetical ideas in abundance. Furthermore, the proposed study underhand, focuses upon bringing to foreground the syntagmatic relation (concept of chain between signifiers as they are employed in linguistic framework or pattern of this poem. Besides, to the fact how text (signifiers acts and reacts (contradicts to its linguistic framework, this paper aims to analyze the variations in tone, attitude and thinking perspectives of speaker in the poem. Furthermore, the close textual analysis, descriptive and interpretive methods as research techniques have been utilized in this study. This research study is likely to contribute to fields of Linguistics, Literary theory and Pakistani literature as a distinct genre.

Changes in Muscle Architecture, Explosive Ability, and Track and Field Throwing Performance Throughout a Competitive Season and After a Taper.

Science.gov (United States)

Bazyler, Caleb D; Mizuguchi, Satoshi; Harrison, Alex P; Sato, Kimitake; Kavanaugh, Ashley A; DeWeese, Brad H; Stone, Michael H

2017-10-01

The purpose of this study was to examine the effects of an overreach and taper on measures of muscle architecture, jumping, and throwing performance in Division I collegiate throwers preparing for conference championships. Six collegiate track and field throwers (3 hammer, 2 discus, 1 javelin) trained for 12 weeks using a block-periodization model culminating with a 1-week overreach followed by a 3-week taper (ORT). Session rating of perceived exertion training load (RPETL) and strength training volume-load times bar displacement (VLd) were recorded weekly. Athletes were tested pre-ORT and post-ORT on measures of vastus lateralis architecture, unloaded and loaded squat and countermovement jump performance, underhand and overhead throwing performance, and competition throwing performance. There was a statistical reduction in weight training VLd/session (d = 1.21, p ≤ 0.05) and RPETL/session (d = 0.9, p ≤ 0.05) between the in-season and ORT training phases. Five of 6 athletes improved overhead throw and competition throwing performance after the ORT (d = 0.50, p ≤ 0.05). Vastus lateralis muscle thickness statistically increased after the in-season training phase (d = 0.28, p ≤ 0.05) but did not change after the ORT. Unloaded countermovement jump peak force and relative peak power improved significantly after the ORT (d = 0.59, p ≤ 0.05, d = 0.31, p ≤ 0.05, respectively). These findings demonstrate that an overreaching week followed by a 3-week taper is an effective means of improving explosive ability and throwing performance in collegiate track and field throwers despite the absence of detectable changes in muscle architecture.

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

Principles of integrated modeling of coal seam mining

Energy Technology Data Exchange (ETDEWEB)

Magda, R

1983-01-01

Mathematical modeling of underground coal mining is discussed. Construction of a mathematical model of an underground mine is analyzed. The model is based on integrating the elementary units (modules). A so-called elementary mining field is defined with the example of a longwall face. A model of an elementary coal seam zone is constructed by integrating the elementary mining fields (in time and space) and supplementing them with a suitable model of mine roadway structure. By integrating the elementary coal seam zones a model of mining level is constructed. Such a mathematical model is used for optimizing the selected mining parameters e.g. structure of mine roadways, size of a coal mine, and organizational scheme of underground mining in a mine or in a mine section using the standardized optimization criterion e.g. investment. Use of the integration model of underground mining for optimizing coal mine construction is evaluated. The following elements of investment and operating cost are considered: shaft excavation, shaft equipment, investment in mining sections, ventilation, mine draining etc. 1 reference.

Control over surrounding rocks deformation of soft floor and whole-coal gateways with trapezoidal supports

Energy Technology Data Exchange (ETDEWEB)

Zhai, X.; Li, D.; Shao, Q.; Sun, Y. [Henan Polytechnic University, Jaozuo (China). Dept. of Resource and Material Engineering

2005-06-01

The coal seams of Guengcun Coal mine of Yima Coal Group Co. Ltd. are prone to spontaneous combustion. Fully mechanized longwall mining with sublevel caving is used as the mining method. Based on the characteristics of the gateways of the 1301 coal face and of the roof coal seams, the natural equilibrium arch theory was used to design the parameters of 11 mine-type metal supports. Then, in-situ supporting experiments were carried out. The results indicate that under the action of virgin rock stress, the width of broken rocks zone of surrounding rocks is 1.7-2.0 m in the return heading and 1.1-1.3 m in the outgoing headway and their surrounding rocks belong to the IV-type soft rock and the III-type common surrounding rock respectively. Therefore, under the movable abutment pressure, the gateway deformation is serious. At the same time, the accumulated water on gateway floor must be drained in time. These measures were taken in the 1302 and 1304 coal faces in Gengcun colliery, and satisfactory results have been obtained. 8 refs., 3 figs.

The Mine Safety and Health Administration's criterion threshold value policy increases miners' risk of pneumoconiosis.

Science.gov (United States)

Weeks, James L

2006-06-01

The Mine Safety and Health Administration (MSHA) proposes to issue citations for non-compliance with the exposure limit for respirable coal mine dust when measured exposure exceeds the exposure limit with a "high degree of confidence." This criterion threshold value (CTV) is derived from the sampling and analytical error of the measurement method. This policy is based on a combination of statistical and legal reasoning: the one-tailed 95% confidence limit of the sampling method, the apparent principle of due process and a standard of proof analogous to "beyond a reasonable doubt." This policy raises the effective exposure limit, it is contrary to the precautionary principle, it is not a fair sharing of the burden of uncertainty, and it employs an inappropriate standard of proof. Its own advisory committee and NIOSH have advised against this policy. For longwall mining sections, it results in a failure to issue citations for approximately 36% of the measured values that exceed the statutory exposure limit. Citations for non-compliance with the respirable dust standard should be issued for any measure exposure that exceeds the exposure limit.

Effects of natural conditions on development of a landslide at a mining area

Energy Technology Data Exchange (ETDEWEB)

Palki, J

1982-01-01

Investigations show that 39.4% of landslides at the mining ground in the Rybnik coal region is caused by factors other than underground mining. Determining the actual cause of a landslide is of importance for an underground mine because, as a rule, all ground damage is claimed to be caused by underground mining. A case of a landslide in the Rybnik area is analyzed. Landslide development is shown in a photo and 17 schemes. Ground morphology, water conditions and effects of underground longwall mining are evaluated. The analyses show that ground subsidence caused by underground mining ranging from 2.0 m to 3.1 m reduced the angle of slope inclination preventing more intensive landslides. Intensity of horizontal deformation was too low to cause a landslide. Slope stability decrease was caused by loose rock layers (sands) at the base of a hill. Accumulation of atmospheric precipitation and disturbed water outflow caused an increase in the plasticity of the sand. Mechanical vibrations caused by train traffic on tracks located close to the slope were an additional factor causing landslide development. (6 refs.)

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.

Controlling ventilation for safe escape from coal mine fires

Energy Technology Data Exchange (ETDEWEB)

Wala, A M [University of Kentucky, Lexington, KY (United States). Mining Engineering Dept.

1966-04-01

If a fire occurs outby an underground coal mine section, the immediate safe evacuation of miners from the working section should always take precedence. Unfortunately, in many cases, the dedicated escapeway (escape routes) for the evacuation of the miners become contaminated by the byproducts of fire from the adjacent entries. The purpose of this paper is to present the ventilation-control process that would keep the escapeway free from contaminants and, thus, available for travel. A few scenarios of mine fires in longwall development panels are analysed and discussed. To perform these studies, a mine-fire simulator (MFS) was used. This (MFS) provides a dynamic representation of the fire`s progress (in real time) and gives a color-graphic visualization of the spready of oxygen, combustion products and temperature of the gases throughout the ventilation system. Also presented and discussed are ways in which the MFS can be used as a training and teaching tool for miners and particularly, for ventilation and safety specialists. 7 refs., 10 figs.

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.

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.

Dynamic Behavior of Fault Slip Induced by Stress Waves

Directory of Open Access Journals (Sweden)

Guang-an Zhu

2016-01-01

Full Text Available Fault slip burst is a serious dynamic hazard in coal mining. A static and dynamic analysis for fault slip was performed to assess the risk of rock burst. A numerical model FLAC3D was established to understand the stress state and mechanical responses of fault rock system. The results obtained from the analysis show that the dynamic behavior of fault slip induced by stress waves is significantly affected by mining depth, as well as dynamic disturbance intensity and the distance between the stope and the fault. The isolation effect of the fault is also discussed based on the numerical results with the fault angle appearing to have the strongest influence on peak vertical stress and velocity induced by dynamic disturbance. By taking these risks into account, a stress-relief technology using break-tip blast was used for fault slip burst control. This technique is able to reduce the stress concentration and increase the attenuation of dynamic load by fracturing the structure of coal and rock. The adoption of this stress-relief method leads to an effective reduction of fault slip induced rock burst (FSIRB occurrence.

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.

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

Directory of Open Access Journals (Sweden)

Esperanza García-Gonzalo

2016-06-01

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

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

Science.gov (United States)

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

2016-06-29

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

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

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.

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.

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

Parameters of Solidifying Mixtures Transporting at Underground Ore Mining

Science.gov (United States)

Golik, Vladimir; Dmitrak, Yury

2017-11-01

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.

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

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

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Seismic risk mitigation in deep level South African mines by state of the art underground monitoring - Joint South African and Japanese study

Science.gov (United States)

Milev, A.; Durrheim, R.; Nakatani, M.; Yabe, Y.; Ogasawara, H.; Naoi, M.

2012-04-01

quantify post slip behavior of the source. An attempt to associate the different type of deformations with the various fracture regions and geological structures around the stopes was carried out. A model, was introduced in which the coseismic deformations are associated with the stress regime outside the stope fracture envelope and very often located on existing geological structures, while the aseismic deformations are associated with mobilization of fractures and stress relaxation within the fracture envelope. Further research to verify this model is strongly recommended. This involves long term underground monitoring using a wide variety of instruments such as tilt, closure and strain meters, a highly sensitive AE fracture monitoring system, as well as strong ground motion monitors. A large amount of numerical modeling is also required.

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".

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.

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.

Management information systems

Energy Technology Data Exchange (ETDEWEB)

1991-01-01

This contract was for the development of a new range of colliery information computer systems (CIS) using a VAX 11/730 computer. The report details the selection of the system and the set-up of the hardware and software. The first application of these systems was to monitor production and delays from longwall faces. A trial installation was implemented at Shirebrook Colliery and this proved so successful that British Coal are now installing many similar systems. The key features of the production monitoring application are that delays are automatically detected in real time and the operator is prompted for the root cause of the delay. This is done through a linked series of questions and answere from a linked set of possible delay causes. Ad hoc and regular reports are produced giving local colliery management visibility of coal face performance, thus enabling informed decisions and corrective action to be taken. Following the successful application to production monitoring, the system was extended to heading/drivages, coal clearance/conveyors, mine air environment and fixed plant. Those applications were operational during the contract but have since been extended.

Report on a commercialization fundamental investigation (in Batulicin Area, Indonesia) in relation to FY 1997 investigations on geological structures in overseas countries; 1997 nendo kaigai chishitsu kozo nado chosa ni kakawaru kigyoka kiso chosa (Indonesia Batulicin chiku) hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-03-01

A fundamental coal mine development investigation was carried out in Batulicin Area, Kalimantan, the Republic of Indonesia. The investigation included ground surface surveys, preparation of topographical maps and geological maps, trial drilling investigation, physical logging, chemical analysis, and infrastructure investigation. The trial drilling investigation was intended to identify the existence conditions of coal beds and coal quality, and was performed by forming grids with about 500-meter interval, and using 21 trial drillings to depths of 104 to 240 meters for a total drilling length of 3463 meters. The physical logging included electric logging, radioactivity logging and pore size logging, and the trial drilling cores were subjected to chemical analysis. For infrastructures, investigations were carried out on necessity of modifying existing roads, privilege relationship, the current status of barge loading points, water depths, and land acquisition. The result of the investigation revealed that minable coal quantity in underground mining of the coal bed B would be 13.189 million tons, and that annual production of original coal at 733,000 tons would be possible by adopting a long-wall type mechanized coal mining system. 14 refs., 99 figs., 25 tabs.

A coal combine

Energy Technology Data Exchange (ETDEWEB)

Wlachovsky, I; Bartos, J

1980-02-15

A design is presented for a coal combine, equipped with two drum operational units, on whose both ends of the upper surface of the body, two coal saws are mounted with the help of a lever system. These saws, found in an operational position, form a gap in the block of the coal block, which is not embraced by the drum operational unit. The coal block, found between the gap and the support, falls down onto the longwall scraper conveyor. The lever system of each coal saw is controlled by two hydraulic jacks. One of the jacks is mounted vertically on the facial wall of the body of the combine and is used for the hoisting for the required height of the horizontal arm of the lever, reinforced by one end in the hinge on the body of the combine. On the ''free'' end of that lever, a coal saw is mounted in a hinge-like fashion and which is connected by the hydraulic jack to the horizontal arm of the lever system. This hydraulic jack is used for the clamping of the coal saw to the face.

Perspectives of roof bolt use in the Kuzbass

Energy Technology Data Exchange (ETDEWEB)

Shirokov, A P

1983-10-01

Use of roof bolting for strata control in mine roadways and underground chambers in Kuzbass mines is discussed. Use of roof bolting in the Kuzbass is increasing. In 1982 roof bolting was used in 50% of workings driven in the basin; in 15 coal mines roof bolting was the predominant method for strata control. Use of roof bolting rather than timber props permitted advance rate of mine drivage in the Kuzbass to be increased by 1.5-2.0 times. Interaction between roof bolts and rock strata is analyzed. The following bolt types are considered: timber roof bolts, steel expansion shell bolts and thread bar bolts. Bolt design is shown, along with methods for roof bolt installation in roadways and chambers. Roof bolting during level, inclined or steep seam mining, for strata control at junctions of working faces with gate roads, at junctions of 2 roadways, in coal chutes, in hydraulic mines, during thick seam slicing with hardening stowing and longwall mining with hydraulic stowing is analyzed. Effects of roof bolting on strata control efficiency in steep coal mines employing AShchM systems are evaluated.

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

Mechanization of operations in underground workings in coal mines and research project trends. [Poland

Energy Technology Data Exchange (ETDEWEB)

Reich, K; Skoczynski, W; Sikora, W

1985-01-01

Structure of black coal reserves of Poland, imported and Polish made equipment for underground mining, prospects for mechanization of selected operations in underground mines and research programs of the KOMAG Center for Mechanization of Mining are evaluated. Prospects for longwall mining with caving or stowing in thick coal seams (slice mining), thin (0.8 to 1.2 m), level or inclined coal seams and steep seams are analyzed. The following equipment for mechanization of underground mining is evaluated: integrated face systems, shearer loaders, chain conveyors, belt conveyors, coal plows, equipment for mine drivage, hoists, drive systems for mining equipment. The following research programs of the KOMAG Center are reviewed: modernization of face systems for coal seams with uncomplicated mining conditions, development of equipment for thin seam mining, development of types of mining equipment for coal seams from 1.5 to 3.0 m thick with dip angles to 25 degrees, modernization of equipment for thick seam mining, increasing efficiency of mine drivage (new types of heading machines, materials handling equipment for mine drivage), mechanization of auxiliary operations in underground coal mines, improving quality of mining equipment, development of equipment for coal preparation, increasing occupational safety in underground mining.

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.

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.

The influence of the formation pitching angle on the area for employing the KM-103 complex

Energy Technology Data Exchange (ETDEWEB)

Shulga, A I; Teryanik, V I

1982-01-01

Mining sections in which the KM-103 powered complexes are used should be selected and planned on the basis of the actual pitching angle of the formation, and the anticipated vertical and lateral rock displacement in the workings. With the shapes and dimensions characteristic of galley cross-sections which are reinforced by arched 3 and 5-arm supports, and with the anticipated values of rock displacement, a maximum pitching angle exists, above which it is difficult to facilitate the drives of stope face conveyors. For arch-shaped galleys, which are reinforced by an arched 5-arm support, the maximum pitching angle of the formation is greater than in galleys which are reinforced by arched three-arm supports, with equal cross-sections even with large rock displacements. An increase in the cross-section of upwards of 13 square meters does not result in an increase in the maximum pitching angle of the formation due to the extension of the support roof timber. In the trapezoidal workings which are supported by the KPS-3 supports and are worked without employing roof blasting, the maximum pitching angle of the formation is 12 degrees. The thickness of the formation worked must be less than 1.1 meter.

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

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.

[Piezosurgery for surgically assisted rapid maxillary expansion under local anesthesia].

Science.gov (United States)

Sun, Hao; Li, Biao; Sun, Hao; Liu, Zhixu; Wang, Xudong

2014-08-01

This study evaluates piezosurgery for surgically assisted rapid maxillary expansion (SARME) under local anesthesia. SARME was performed on adults with maxillary transverse deficiency under local anesthesia with a piezosurgical device. Fourteen patients (six males and eight females) underwent lateral maxillary osteotomies, midpalatal osteotomies, and bilateral pterygomaxillary disjunction. The feelings of patients during the operation were determined through questionnaires. All patients underwent SARME in the out-patient operating room. The surgical procedures were completed under local anesthesia. All patients exhibited satisfactory tolerance. Ultrasonic bone-cutting surgery was recently introduced as a feasible alternative to the conventional tools of cranio-maxillofacial surgery for its technical characteristics of precision and safety. The device used was unique in that cutting action occurred when the tool was employed on mineralized tissues, but stoped on soft tissues. The results of the questionnaires showed that eight (57.14%) patients felt a mild sensation of ultrasonic vibration, tweleve (85.7 1%) felt mild tolerable pain and tooth soreness during surgery, and eleven (78.57%) felt little fear and hardly heard the ultrasonic sound. Preoperative and postoperative six months later measurements showed an evident effect of expansion. Piezosurgery enabled patients to undergo all the steps of SARME under local anesthesia, but more cases and longer follow-up are needed to verif ' the results.

Uranium mill tailings backfill management. Final report

International Nuclear Information System (INIS)

Thomson, B.M.; Heggen, R.J.

1984-01-01

Backfilling, the disposal of spent uranium mill tailings in empty mine stopes, has been practiced in the Grants Mineral Belt of New Mexico for nearly 20 years. The principal objective of backfilling is the prevention of roof collapse and hydraulic connection with overlying aquifers, increasing mine dewatering requirements. Backfilling is accomplished by gravity feed of a slurry of sand-fraction tailings and treated mine water into the slope. The effects of backfilling on surface discharge of mine wastewater are negligible due to the small fraction of the total flow represented by slurry decant. Furthermore, quality of the decant is not significantly below that of other mine waters. Groundwater effects of backfilling may be classified as short-term (while the mine is operational) and long-term (after dewatering operations have been terminated). Short-term effects are insignificant because of rapid and continuous flow to the mine sump. Long-term effects on aquifer water quality are predicted to be minimal due to (1) the small amount of slurry liquor present after drainage, (2) the precipitation of SO 4 and CO 3 phases, and (3) the reestablishment of reducing conditions and subsequent precipitation of major contaminants including U, As, Mo, Se, and V. 28 references, 19 figures, 9 tables

A Complementary Vision Strategy for Autonomous Robots in Underground Terrains using SRM and Entropy Models

Directory of Open Access Journals (Sweden)

Omowunmi Isafiade

2013-09-01

Full Text Available This work investigates robots' perception in underground terrains (mines and tunnels using statistical region merging (SRM and the entropy models. A probabilistic approach based on the local entropy is employed. The entropy is measured within a fixed window on a stream of mine and tunnel frames to compute features used in the segmentation process, while SRM reconstructs the main structural components of an imagery by a simple but effective statistical analysis. An investigation is conducted on different regions of the mine, such as the shaft, stope and gallery, using publicly available mine frames, with a stream of locally captured mine images. Furthermore, an investigation is also conducted on a stream of dynamic underground tunnel image frames, using the XBOX Kinect 3D sensors. The Kinect sensors produce streams of red, green and blue (RGB and depth images of 640 × 480 resolution at 30 frames per second. Integrating the depth information into drivability gives a strong cue to the analysis, which detects 3D results augmenting drivable and non-drivable regions in 2D. The results of the 2D and 3D experiment with different terrains, mines and tunnels, together with the qualitative and quantitative evaluations, reveal that a good drivable region can be detected in dynamic underground terrains.

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 locations of rock failure. A study of AE in the Ezulwini gold mine in South Africa has been conducted under the Japan–South Africa collaborative project titled “Observational studies to mitigate seismic risks in mines”, in which a large number of events have...

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

A physical and numerical modelling investigation of the roadway stability in longwall mining, with and without narrow pillar protection

Energy Technology Data Exchange (ETDEWEB)

Yavuz, H.; Fowell, R.J. [Suleyman Demirel University, Isparta (Turkey)

2004-03-01

The drivage of the supply gate of a development panel in the presumed low stress zone adjacent to the loader gate of an excavated panel with a very small width of intervening pillar between the two entries, known as skin-to-skin working, resulted in an extensive fall of the supply gate roof at Bilsthorpe colliery in 1993. This fall left a question over the application of skin-to-skin drivage of gate entries supported primarily by rock bolts. To investigate the possible reasons behind this fall, both physical and numerical modelling studies were carried out. Physical and numerical models were successful in demonstrating the potential danger of the working method with the rock bolt support system employed. Development of a shear failure plane from the rib edge into roof strata of the loader gate and development of the second shear failure plane at the abutment side of the supply gate exposed the supply gate to the fall of large rock blocks released by shear failure zones. Models demonstrated that the fall of the supply gate roof was not due to the inability of the rock bolts to prevent bed separation, but it was the method of working that made the bolts ineffective due to the height of the block delineated by the shear failure planes. Further physical and numerical models were undertaken to investigate the influence of 5, 7.5 and 10 in wide intervening pillars between the entries on the stability of the rock bolt supported supply gate roof. These studies showed that a 7.5 in or 10 in wide pillar would have prevented development of failure zones and fall of the roof while a 5 in pillar was found to be an undersized pillar width causing the development of extensive failure zones in the roof.

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...

Automation of the shearer loader technique - an overview; Automatisierung der Walzenladertechnik - ein Ueberblick

Energy Technology Data Exchange (ETDEWEB)

Hackelboerger, B.; Hoelling, B. [Eickhoff Bergbautechnik GmbH, Bochum (Germany); Nienhaus, K.; Winkel, R. [RWTH Aachen (DE). Lehr- und Forschungsgebiet Betriebsmittel fuer die Gewinnung mineralischer Rohstoffe (BGMR)

2007-09-06

The present paper deals with the automation of the shearer loader technology. Starting with the reasons for automation: These are firstly the increase of production by way of rationalization, secondly the gentle material handling associated with health protection and safety at work. Consecutive the development of the automation concept by Eickhoff Bergbautechnik GmbH is being presented which commenced in 1986 with the introduction of the Memory Cut at DSK and successfully continued in 1993 with the first-time utilization of the Defined Face Opening (DFO) in Australia. The authors will present the state-of-the-art in the automation of Eickhoff shearer loaders with the EiControl concept. Besides tramming and ranging arm autosteering it comprises further additional modules for the automatic and semi-automatic cutting sequence to enable control and stabilization of the machine. An overview of the supplied systems combined with the experiences made by the respective mine operators will complete our glance at today's opportunities provided by the advanced shearer loader technology. The Outlook discusses the existing limits of automation and presents future development potentials such as coal boundary layer detection and collision prevention which paves the road to automatic longwall control with the vision of an unmanned face. (orig.)

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.

Fiscal 1999 report on basic research for promotion of joint implementation programs. Research on collection and utilization of coal mine methane gas in Russia (Kuznetsk coal field); Russia (Kuznetsk tanden) ni okeru tanko methane gas kaishu riyo chosa hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

The above-mentioned effort is to comply with the COP3 (Third Session of the Conference of the Parties to the United Nations Framework Convention on Climate Change) joint implementation clause. At this coal field, mining facilities are growing superannuated and obsolescent in the prolonged business depression, causing frequent occurrence of disasters such as gas explosions. The coal mine gas collection rate at the Kuznetsk coal field is as low as 17%, with concern for safety discouraging sufficient collection. Even the small amount of the collected gas is, in the absence of gas utilizing facilities, totally discharged into the air. For the mitigation of global warming, for mining safety, and for the establishment of a foundation for business, it is desired that coal mine methane gas collection/utilization facilities and related technologies be introduced into the coal field. Gas purging from the pits is incomplete, which is attributed to the lack of equipment capable of excavating proper-diameter bores longer than 100m for longwall mining. Ventilation also needs improvement. The research is under way on the premise that highly reliable intermediate range (300m) boring equipment and gas management technologies will be available. Collection of gas of a 30-35% concentration level at a collection rate of 40% is the target. (NEDO)

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.

Availability analysis of selected mining machinery

Directory of Open Access Journals (Sweden)

Brodny Jarosław

2017-06-01

Full Text Available Underground extraction of coal is characterized by high variability of mining and geological conditions in which it is conducted. Despite ever more effective methods and tools, used to identify the factors influencing this process, mining machinery, used in mining underground, work in difficult and not always foreseeable conditions, which means that these machines should be very universal and reliable. Additionally, a big competition, occurring on the coal market, causes that it is necessary to take action in order to reduce the cost of its production, e.g. by increasing the efficiency of utilization machines. To meet this objective it should be pro-ceed with analysis presented in this paper. The analysis concerns to availability of utilization selected mining machinery, conducted using the model of OEE, which is a tool for quantitative estimate strategy TPM. In this article we considered the machines being part of the mechanized longwall complex and the basis of analysis was the data recording by the industrial automation system. Using this data set we evaluated the availability of studied machines and the structure of registered breaks in their work. The results should be an important source of information for maintenance staff and management of mining plants, needed to improve the economic efficiency of underground mining.

Mining the 510 coal seam prone to rock bursts and below a coal support pillar in a seam above

Energy Technology Data Exchange (ETDEWEB)

Major, M; Gebala, W

1983-10-01

The 510 coal seam, situated at a depth of 760 m below a support pillar left in an overlying coal seam, was mined by a system of longwall faces from 1979 to 1982. The seam was prone to rock bursts. Energy of rock bursts which occurred in the mine ranged from 10/SUP/5 to 10/SUP/6 J. The coal seam, 10 m thick, was mined by slicing. Faces were 140 m long. Stress concentrations caused by the suppport pillar left in the overlying coal seam were calculated. Curves which describe stress fluctuations were plotted. Rock burst hazards were determined by drilling. Drilling intervals depended on hazard degree and position of the test site in relation to the support pillar in the overlying coal seam. The face was 3 m high. Supports used in 2 gate roads were reinforced by steel and timber supports. Strong timber boards were placed at canopies of powered supports used at the working face. The face was situated at an angle of 10 degrees to the pillar axis. In the zone of critical stresses water infusion and shock blasting were used for rock burst prevention. These methods, plus reinforcement of the supports in gate roads and at the working face, guaranteed safe mining and prevented rock bursts. (8 refs.)

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

On the problem of technological innovations in driving preparatory workings in thin coal seams

Energy Technology Data Exchange (ETDEWEB)

Peknik, J

1980-03-01

Possibilities of mechanizing preparation of thin coal seams for longwall mining are discussed. Until now preparatory workings in the Ostrava Karvina coal region have been driven mainly by manual work or blasting. Tables show the total length of preparatory workings driven in the period 1973-1978 and the average advance of preparatory working per day and per shift. Factors influencing mechanization of preparatory working drivage are: geological disturbances, angle of seam inclination and its changes, thickness of the seam and strength of coal. Some types of mining machines which can be used for driving preparatory workings in thin, horizontal and inclined coal seams and produced in the USSR and United Kingdom are reviewed. Two sets of machines used in coal seams inclined up to 18 or 20 degrees are presented: KN produced in the USSR and 'In seam Miner' produced by the Dosco firm in the UK. Parameters of both machines are compared. The following Soviet machines for driving preparatory workings in inclined seams are also reviewed: 2 KNP (slope 45-80 degrees), KMD-72 (slope 45-80 degrees, height of the seam 0.6 m to 1.2 m), MRS-2 (slope 45-90 degrees, height of the seam 0.55 m to 1.0 m). (7 refs.) (In Czech)

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.

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.

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.

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)

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)

Azmat, Syed Khurram; Ali, Moazzam; Hameed, Waqas; Mustafa, Ghulam; Abbas, Ghazanfer; Ishaque, Muhammad; Bilgrami, Mohsina; Temmerman, Marleen

2014-05-30

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. 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. 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.

¿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.

Developments in outburst prediction by microseismic monitoring from the surface

Energy Technology Data Exchange (ETDEWEB)

Davies, A W; Styles, P; Jones, V K

1987-01-01

Violent outbursts of coal and firedamp affect production operations in most of the coal producing countries of the world, often leading to heavy loss of life. Significant changes in the pattern of Welsh outbursts from 1978 onwards are described with a far larger proportion occurring on longwall faces than was previously the case and with a much higher incidence of spontaneous outbursts, which carry a greater risk than those which are deliberately induced. The elaborate defences in use appeared inadequate to deal with the changing circumstances as methane based alarms only operated after the outburst phenomenon had initiated. An earlier warning of an incipient outburst was required and evidence suggested that seismic monitoring might provide this early warning. A surface located seismometer was installed giving radio transmitted signals to a tape recorder in the colliery control room. This provided promising historical records and led to five surface seismometer stations being commissioned feeding signals, suitably treated, to a micro-processor located in the mine control room. The programming of the micro-processor was arranged to give a real time alarm at pre-set levels of seismic activity in defined areas of the mine. Experience with the new predictive tool is described, as well as the use made of the new facility by management, including changed methods of outburst stress relief.

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.

Engineer exchanging project on coal mine technology field in fiscal 1999. International information exchanging project (advance survey on North America); 1999 nendo gijutsusha koryu jigyo (tanko gijutsu bun'ya) kokusai koryu jigyo. Jizen chosa (Hokubei)

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

This project has been performed with an intention of making visiting surveys and information collection at coal related organizations in overseas coal producing countries on production technology levels and trends. The project is intended to serve for improvement in the contents of and smooth execution of the engineer exchange project in the 'coal mine technology field. It was carried out by the site surveys. The surveys revealed that the situation of the American coal industry is expected of stable increase in the demand and supply in the future, but the coal price is on the falling trend, and therefore, the industry is compelled to further increase the intensity and enhance the productivity. The industry is strongly influenced by the amended air pollution prevention act and nature destruction problems, hence further coal mine curtailment is estimated. Under such a background, it was found that the long-wall mining process progressing toward larger scale and higher productivity, and the high-wall mining process that provides higher productivity at lower cost and has less impact on the environmental problems can continue development in mountainous areas, particularly in the Appalachian area. The high-wall mining process mines coal at exposed facings on the side of a mountain by using a continuous miner, and transports the coal using machines. (NEDO)

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.

Mining aspects of hard to access oil sands deposits

Energy Technology Data Exchange (ETDEWEB)

Stephenson, G.; Wright, D.; Lukacs, Z. [Norwest Corp., Calgary, AB (Canada)

2006-07-01

While a variety of oil sands mining technologies have been explored since the 1960s, the oil sands industry has generally favoured truck and shovel mining as a proven, low-cost mining solution. However, surface mining economics are affected by the price of bitumen, haul distances, tailings storage and geotechnical constraints. Maintenance, labour and the cost of replacing tires and ground engaging tools also have a significant impact on the economics of surface mining. Large volumes of water are used in surface mining, and remediation of surface mined areas can take hundreds of years. Damage to machinery is common as oil sands are abrasive and adhere to equipment. This presentation examined recent technologies developed to improve the economics of surface mining. Various extraction and tailings technologies were reviewed. Issues concerning the integration of mining and extraction processes were discussed. Various monitoring tools were evaluated. A review of new underground mining options included outlines of: longwall mining; sub-level caving; tunnel boring; and room and pillar extraction techniques. A generalized regional geology was presented. It was concluded that the oil sands surfacing mining industry should concentrate on near-term research needs to improve the performance and economics of proven technologies. Screening studies should also be conducted to determine the focus for the development of underground technologies. refs., tabs., figs.

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.

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.

Analysis of Mining-induced Valley Closure Movements

Science.gov (United States)

Zhang, C.; Mitra, R.; Oh, J.; Hebblewhite, B.

2016-05-01

Valley closure movements have been observed for decades in Australia and overseas when underground mining occurred beneath or in close proximity to valleys and other forms of irregular topographies. Valley closure is defined as the inward movements of the valley sides towards the valley centreline. Due to the complexity of the local geology and the interplay between several geological, topographical and mining factors, the underlying mechanisms that actually cause this behaviour are not completely understood. A comprehensive programme of numerical modelling investigations has been carried out to further evaluate and quantify the influence of a number of these mining and geological factors and their inter-relationships. The factors investigated in this paper include longwall positional factors, horizontal stress, panel width, depth of cover and geological structures around the valley. It is found that mining in a series passing beneath the valley dramatically increases valley closure, and mining parallel to valley induces much more closure than other mining orientations. The redistribution of horizontal stress and influence of mining activity have also been recognised as important factors promoting valley closure, and the effect of geological structure around the valley is found to be relatively small. This paper provides further insight into both the valley closure mechanisms and how these mechanisms should be considered in valley closure prediction models.

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

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

CO2 emissions: mineral carbonation and Finnish pulp and paper industry (CO2 Nordic Plus) and use of serpentinites in energy and metal industry (ECOSERP)

International Nuclear Information System (INIS)

Fogelholm, C.-J.; Raiski, T.; Teir, S.

2007-01-01

Abstract Mineral carbonation has been investigated at Helsinki University of Technology (TKK), laboratory of energy engineering and environmental protection since year 2000. The Finnish Technology Agency Tekes and the Finnish Recovery Boiler Committee are funding through the ClimBus technology programme, in conjunction with the Nordic Energy Research Programme, the research regarding the application of ex situ mineral carbonation processes. One aspect is to verify the possible use of mineral carbonation for the separation, utilisation and long-term storage of carbon dioxide (CO 2 ) in the pulp and paper industry. The Geological Survey of Finland (GTK) has been screening since 2004 the location, quality and suitability of the Finnish processed serpentine and stoped serpentinite storage of mines and in situ serpentinite bodies of ultramafic rock formations for mineral carbonation of CO 2 . Tekes and the GTK are funding development work through the ClimBus technology programme on the utilisation of serpentine and serpentinite for CO 2 sequestration purposes, based on economical and environmental evaluation of mineral and mining processing operations. Also the options for other use of serpentine and serpentinite are evaluated. The most promising magnesium- and calcium-based sources for carbonation are by-products of mining processes of ultramafic rocks (such as serpentinites and serpentine) and steelmaking slags. Carbonated minerals could possibly be used as paper coating materials (PCC), fillers or construction materials. For magnesium carbonate new markets and applications must be developed. (orig.)

The nature of a deformation zone and fault rock related to a recent rockburst at Western Deep Levels Gold Mine, Witwatersrand Basin, South Africa

Science.gov (United States)

Stewart, R. A.; Reimold, W. U.; Charlesworth, E. G.; Ortlepp, W. D.

2001-07-01

In August 1998, a major deformation zone was exposed over several metres during mining operations on 87 Level (2463 m below surface) at Western Deep Levels Gold Mine, southwest of Johannesburg, providing a unique opportunity to study the products of a recent rockburst. This zone consists of three shear zones, with dip-slip displacements of up to 15 cm, that are oriented near-parallel to the advancing stope face. Jogs and a highly pulverised, cataclastic 'rock-flour' are developed on the displacement surfaces, and several sets of secondary extensional fractures occur on either side of the shear zones. A set of pinnate (feather) joints intersects the fault surfaces perpendicular to the slip vector. Microscopically, the shear zones consist of two pinnate joint sets that exhibit cataclastic joint fillings; quartz grains display intense intragranular fracturing. Secondary, intergranular extension fractures are associated with the pinnate joints. Extensional deformation is also the cause of the breccia fill of the pinnate joints. The initial deformation experienced by this zone is brittle and tensile, and is related to stresses induced by mining. This deformation has been masked by later changes in the stress field, which resulted in shearing. This deformation zone does not appear to be controlled by pre-existing geological features and, thus, represents a 'burst fracture', which is believed to be related to a seismic event of magnitude ML=2.1 recorded in July 1998, the epicentre of which was located to within 50 m of the study locality.

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.

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.

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.

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.

Naesliden Project: why, what for, and how

Energy Technology Data Exchange (ETDEWEB)

Kolsrud, B.

1980-05-15

Mechanization of cut-and-fill mining has resulted in larger span of mine openings as well as in demands on lower frequency of disruptions due to mine stability problems. These demands arose due to the heavy investment in machines as well as in preparation works per stope. Better knowledge of the rock mechanics of the mining method became a necessity. For this purpose it was decided to run a systematic monitoring program from the very start of mining at Boliden's Naesliden Mine in order to obtain a comprehensive record of the reaction of the rock mass to mining. It was also recognized that, for the purpose of prediction of future mining conditions, the use of reliable numerical models for mine design would be an advantage. The access to rock mechanics observations of the Naesliden Mine made it possible to evaluate the reliability of numerical modelling techniques as a practical planning tool in mining. This evaluation is the aim of the Naesliden Project. The project was organized in five stages; data collection and preliminary calculations. Establishing a FEM-model of the Naesliden Mine, based exclusively on the input parameters in stage 1 and comparison of model and mine behavior. Sensitivity aspects of the FEM-model and supplementary determination of input data. Development of an improved model based on sensitivity analysis and information derived from prototype behaviour. Application of the results to practical mining situation. This stage is not part of the study hiterto carried out.

Naesliden Project: why, what for, and how

Energy Technology Data Exchange (ETDEWEB)

Kolsrud, B.

1980-05-15

Mechanization of cut-and-fill mining has resulted in larger span of mine openings as well as in demands on lower frequency of disruptions due to mine stability problems. These demands arose due to the heavy investment in machines as well as in preparation works per stope. Better knowledge of the rock mechanics of the mining method became a necessity. For this purpose it was decided to run a systematic monitoring program from the very start of mining at Boliden's Naesliden Mine in order to obtain a comprehensive record of the reaction of the rock mass to mining. It was also recognized that, for the purpose of prediction of future mining conditions, the use of reliable numerical models for mine design would be an advantage. The access to rock mechanics observations of the Naesliden Mine made it possible to evaluate the reliability of numerical modelling techniques as a practical planning tool in mining. This evaluation is the aim of the Naesliden Project. The project was organized in five stages; data collection and preliminary calculations. Establishing a FEM-model of the Naesliden Mine, based exclusively on the input parameters in stage 1 and comparison of model and mine behavior. Sensitivity aspects of the FEM-model and supplementary determination of input data. Development of an improved model based on sensitivity analysis and information derived from prototype behaviour. Application of the results to practical mining situation. This stage is not part of the study hiterto carried out.

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.

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.

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.

Effects of ventilation tunnel protection on stability

Energy Technology Data Exchange (ETDEWEB)

Strizhiboroda, S K; Kuritsyn, B I; Anosov, O S

1983-09-01

Analyzed are effects of strata control on a ventilation gate road situated at a depth of 860 m in a coal seam 0.65 m thick with dip angle of 48 degrees. The direct roof and floor consisted of limestone and the main roof of shales. The ventilation gate road with a cross section of 8.2 m/Sup 2/ was supported by the AP-9.2 arched steel supports. The following methods for gate road protection were used: timber cribbings, reinforced cribbings, strips of pneumatic stowing (using waste rocks), and coal support pillars. Effects of gate road protection on roof subsidence, subsidence rate and on support deformation in the gate road were analyzed considering strata control method and the distance to the advancing longwall face. The results of comparative evaluations, given in 4 diagrams, showed that timber cribbings guaranteed the most regular stress distribution and regular roof subsidence. Use of coal support pillars negatively influenced stress distribution. Irrespective of strata control method from 60 to 80% of roof subsidence occurred at a distance from 0 to 40 m behind a working face. Roof subsidence ranged from 17.3 to 38.3 mm/d when support pillars were used, was 27 mm/d when reinforced cribbings were used and ranged from 9.6 to 16.5 mm/d when pneumatic stowing was used. Use of blocks of reinforced concrete for protecting ventilation gate roads in inclined strata is recommended.

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

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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.

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

THE STRATEGY OF INCREASING THE COMPETITIVENESS OF ROMANIAN AUTOMOBILE INDUSTRY BY TRANSITION TO ALTERNATIVE ENERGY IN INTERNATIONALIZATION CONDITIONS

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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.

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

Numerical simulation of head top coal's stability control of fully mechanized longwall mining with sublevel caving face in large dip seam

Energy Technology Data Exchange (ETDEWEB)

Li, W.; Wan, Z.; Jiang, F.; Jia, P. [Beijing Science and Technology University, Beijing (China)

2008-07-01

Stability control of the head face's top-coal is one of the key techniques of realising high production and high efficiency in coal mining in fully mechanized top-coal caving face. The characteristics of the stress in the overlying strata of the fully mechanized top-coal caving face and the top coal were analysed using FLAC{sup 3D}. The results show that the tip-to-face top-coal generates a large deformation while it is in the stress-relaxed area. The top-coal in the front of the wall appears to be the failure area for the effect of the abutment pressure that spreads over the coal seam. The surrounding rock of the upper face end is the key part strengthened the control of the rib spalling. The first and frequent appearing phenomenon of losing stability of the powered supports is that the back base of the hydraulic power supports in the top of the face slips. Increasing the quality of support and so on can maintain the stability of surrounding rock. 4 refs., 7 figs., 1 tab.

Gas Permeability Evolution Mechanism and Comprehensive Gas Drainage Technology for Thin Coal Seam Mining

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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.

A Remote Sensing Approach to Environmental Monitoring in a Reclaimed Mine Area

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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.

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.

Case Studies of Rock Bursts Under Complicated Geological Conditions During Multi-seam Mining at a Depth of 800 m

Science.gov (United States)

Zhao, Tong-bin; Guo, Wei-yao; Tan, Yun-liang; Yin, Yan-chun; Cai, Lai-sheng; Pan, Jun-feng

2018-05-01

A serious rock burst ("4.19" event) occurred on 19 April 2016 in the No. 4 working face of the No. 10 coal seam in Da'anshan Coal Mine, Jingxi Coalfield. According to the China National Seismological Network, a 2.7 magnitude earthquake was simultaneously recorded in this area. The "4.19" event resulted in damage to the entire longwall face and two gateways that were 105 m in long. In addition, several precursor bursts and mine earthquakes had occurred between October 2014 and April 2016 in the two uphill roadways and the No. 4 working face. In this paper, the engineering geological characteristics and in situ stress field are provided, and then the rock burst distributions are introduced. Next, the temporal and spatial characteristics, geological and mining conditions, and other related essential information are reviewed in detail. The available evidence and possible explanations for the rock burst mechanisms are also presented and discussed. Based on the description and analysis of these bursts, a detailed classification system of rock burst mechanisms is established. According to the main causes and different disturbance stresses (i.e., high/low disturbance stresses and far-field/near-field high disturbance stresses), there are a total of nine types of rock bursts. Thus, some guidelines for controlling or mitigating different types of rock bursts are provided. These experiences and strategies not only provide an essential reference for understanding the different rock burst mechanisms, but also build a critical foundation for selecting mitigation measures and optimizing the related technical parameters during mining or tunnelling under similar conditions.

Granitoids of the Dry Valleys area, southern Victoria Land, Antarctica : plutons, field relationships, and isotopic dating

International Nuclear Information System (INIS)

Allibone, A.H.; Cox, S.C.; Johnstone, R.D.

1993-01-01

Detailed mapping throughout much of the Dry Valleys area indicates the region is underlain by 15 major granitoid plutons and numerous smaller plugs and dikes. Intrusive relationships of these plutons and dikes indicate repeated intrusion of superficially similar granitoids at different times. Sufficient internal lithologic variation occurs within individual plutons, to allow correlation with several of the previously defined granitoid units based on lithologic character. Consequently, previous subdivision schemes based on lithology are no longer tenable and are here replaced with a subdivision scheme based on the identification of individual plutons. The elongate, concordant Bonney, Denton, Cavendish, and Wheeler Plutons, which range in composition between monzodiorite and granodiorite, are the oldest relatively undeformed plutons in the Dry Valleys area. Each pluton is characterised by flow alignment of K-feldspar megacrysts, hornblende, biotite, and mafic enclaves. Field relationships and radiometric dating indicate these are deep-level plutons, emplaced synchronous with upper amphibolite facies metamorphism of the adjacent Koettlitz Group between 589 and 490 Ma ago. Elongate, discordant plutons of equigranular homogeneous biotite granodiorite and granite (Hedley, Valhalla, St Johns, Suess) were subsequently emplaced by stoping at a relatively high crustal level at 490 Ma. These eight plutons are cut by numerous swarms of Vanda mafic and felsic porphyry dikes. The ovoid, discordant, high level Pearse, Nibelungen, Orestes, Brownworth, Swinford, and Harker Plutons, emplaced between c. 486 and 477 Ma, display mutually crosscutting relationships with the youngest of the Vanda dikes. These younger plutons range in composition between monzonite and granite. Some are characterised by K-feldspar megacrystic textures superficially similar to some of the oldest concordant plutons. (author). 57 refs.; 2 tabs.; 4 figs

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.

Differential diagnosis of recurrent bronchitis in children

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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. 

Radon emanation from backfilled mill tailings in underground uranium mine.

Science.gov (United States)

Sahu, Patitapaban; Mishra, Devi Prasad; Panigrahi, Durga Charan; Jha, Vivekananda; Patnaik, R Lokeswara; Sethy, Narendra Kumar

2014-04-01

Coarser mill tailings used as backfill to stabilize the stoped out areas in underground uranium mines is a potential source of radon contamination. This paper presents the quantitative assessment of radon emanation from the backfilled tailings in Jaduguda mine, India using a cylindrical accumulator. Some of the important parameters such as (226)Ra activity concentration, bulk density, bulk porosity, moisture content and radon emanation factor of the tailings affecting radon emanation were determined in the laboratory. The study revealed that the radon emanation rate of the tailings varied in the range of 0.12-7.03 Bq m(-2) s(-1) with geometric mean of 1.01 Bq m(-2) s(-1) and geometric standard deviation of 3.39. An increase in radon emanation rate was noticed up to a moisture saturation of 0.09 in the tailings, after which the emanation rate gradually started declining with saturation due to low diffusion coefficient of radon in the saturated tailings. Radon emanation factor of the tailings varied in the range of 0.08-0.23 with the mean value of 0.21. The emanation factor of the tailings with moisture saturation level over 0.09 was found to be about three times higher than that of the absolutely dry tailings. The empirical relationship obtained between (222)Rn emanation rate and (226)Ra activity concentration of the tailings indicated a significant positive linear correlation (r = 0.95, p < 0.001). This relationship may be useful for quick prediction of radon emanation rate from the backfill material of similar nature. Copyright © 2014 Elsevier Ltd. All rights reserved.

Women's views and experiences of a mobile phone-based intervention to support post-abortion contraception in Cambodia.

Science.gov (United States)

Smith, Chris; Ly, Sokhey; Uk, Vannak; Warnock, Ruby; Free, Caroline

2017-06-12

The MObile Technology for Improved Family Planning (MOTIF) trial assessed a mobile phone-based intervention comprising voice messages and counsellor support to increase post-abortion contraception at four Marie Stopes International clinics in Cambodia. The aim of this process evaluation was to assess women's views and experiences of receiving the MOTIF intervention, gain insights into the mechanism of action of the intervention and seek recommendations for improvements. We conducted a qualitative study comprising15 semi-structured interviews with women who had received the intervention and undertook a simple thematic analysis. We identified themes relating to communication via mobile phone, supporting contraception use, broader post-abortion care, interaction with family and friends and suggestions for improvement. The majority of women were positive about the mobile phone-based intervention to support contraception use and reported it to be a convenient way to ask questions or get advice without going to a health centre, although a few women found the voice messages intrusive. The intervention supported contraception use by provision of information, encouragement, reminders to return to clinic, reassurance and advice for problems and had a positive effect on contraceptive uptake and continuation. Women reported a sense of being cared for and received support for additional physical and emotional issues. Most women thought that the duration of the intervention and frequency of messages were acceptable. The majority of women were positive about the mobile phone-based intervention which provided support for contraception use as well as additional physical and emotional issues. The study provides some insights into how the intervention might have worked and considers how the intervention could be improved.

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

Geoscientific investigations in the abandoned iron ore mine Konrad for safe disposal of certain radioactive waste categories

International Nuclear Information System (INIS)

Brewitz, W.

1980-01-01

Besides the disposal of high-active waste in a salt formation the national policy of the Federal Republic of Germany provides for a second underground storage facility for non-α-emitting and low-active waste. Due to the short decay times of such wastes the demands made on the geological barrier are in some respect different, in particular as regards long-term stability and impermeability to liquids. Within the 1000-year-phase all wastes will have reached a concentration with a content of radionuclides far below that of a uranium deposit. The abandoned iron ore mine Konrad (Lower Saxony) has some exceptional geological features which make it a very good choice for a radioactive waste repository. The mine is 1200 m deep. Stopes and galleries are extremely dry. The hanging rock formations are mainly claystones. The mining installations are of modern design. The geological, hydrogeological and geophysical investigations have to examine in detail the covering claystone formations for their extension and mineralization, the origin and the age of the mine's seepage water as well as the mechanical stability of the underground cavities during and after the operational period. Via radiological investigations a catalogue of various low-active waste types, the waste volumina and the total activities accumulating over a period of 30 years is being established. For a safety assessment the hazard indices of a uranium ore deposit containing 0.2 wt% U 3 O 8 and a waste repository corresponding to the above figures were compared. The research programme has not been terminated yet since it is being financed by the Bundesminister fuer Forschung und Technologie (BMFT) of the Federal Republic of Germany until the end of 1981

Public sphere of politics: between classical grounds and new political actuality

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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.

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

Science.gov (United States)

Azmat, Syed Khurram; Hameed, Waqas; Lendvay, Anja; Shaikh, Babar Tasneem; Mustafa, Ghulam; Siddiqui, Muhammad Ahmed; Brohi, Sajid; Karim, Asif; Ishaque, Muhammad; Hussain, Wajahat; Bilgrami, Mohsina; Feldblum, Paul J

2014-01-01

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). 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. 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 users with Femplant (Sino-implant II). This will help to guide policies to enhance access to and the use of long-acting contraceptive implants in Pakistan and similar developing countries.

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

[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

An Experimental Study of Cutting Performances of Worn Picks

Science.gov (United States)

Dogruoz, Cihan; Bolukbasi, Naci; Rostami, Jamal; Acar, Cemil

2016-01-01

The best means to assess rock cuttability and efficiency of cutting process for using mechanical excavation is specific energy (SE), measured in full-scale rock cutting test. This is especially true for the application of roadheaders, often fitted with drag-type cutting tools. Radial picks or drag bits are changed during the operation as they reach a certain amount of wear and become blunt. In this study, full-scale cutting tests in different sedimentary rock types with bits having various degree of wear were used to evaluate the influence of bit wear on cutting forces and specific energy. The relationship between the amount of wear as represented by the size of the wear flats at the tip of the bit, and cutting forces as well as specific energy was examined. The influence of various rock properties such as mineral content, uniaxial compressive strength, tensile strength, indentation index, shore hardness, Schmidt hammer hardness, and density with required SE of cutting using different levels of tool wear was also studied. The preliminary analysis of the data shows that the mean cutting forces increase 2-3 times and SE by 4-5 times when cutting with 4 mm wear flat as compared to cutting with new or sharp wedge shape bits. The grain size distribution of the muck for cutting different rock types and different level of bit wear was analyzed and discussed. The best fit prediction models for SE based on statistical analysis of laboratory test results are introduced. The model can be used for estimating the performance of mechanical excavators using radial tools, especially roadheaders, continuous miners and longwall drum shearers.

The chosen needs of Polish restructured coal mines concerning the ventilation and struggling against gas, dust and air-conditioning dangers

Energy Technology Data Exchange (ETDEWEB)

Matuszewski, K. [Rudzka Coal Company (Poland)

2001-07-01

In this paper the selected needs of Polish coal mines with regard to their ventilation, minimisation of gas, dust and air-shortage dangers are presented. As far as ventilation is concerned: the need to broaden the use of the synchronic inverter cascades for speed regulation of main fans and the delivery of ventilation air duct to ensure a delivery of 11,117 m{sup 3}/s (6,5011,000 m{sup 3}/min) has been shown. As far as gas dangers are concerned there exists a need for the dissemination of dispatcher's help systems, training safety personnel in use of so called synoptic display table, a supply of 0,8311,67 m{sup 3}/s (501,100 m{sup 3}/min) of nitrogen in gaseous state for fire prevention as well as the use of modern mineral and chemical means have been mentioned. In order to help to reduce the dust danger the projected need for a modern generation of dry or wet dust collectors enabling a reduction in dustiness to NDS standards and equipping all longwalls with cutting machines with permanent and working installations of internal sprinklers have been postulated. In the case of air conditioning, the need to install 300 kW movable coolers with 300 kW single gear fans for the supply of 10 m{sup 3}/s (600 m{sup 3}/min) and an overall air pressure increase from 1600 to 2000 Pa has been presented. In the most dangerous coal mines attention has been drawn to the need for the installation and application of stationery coolers operating intermittently. 6 refs.

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.

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

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

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.

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.

Irish women who seek abortions in England.

Science.gov (United States)

Francome, C

1992-01-01

In 1991, 4158 women from Ireland and 1766 from Northern Ireland traveled to England for abortions. This situation has been ignored by Irish authorities. The 1992 case of the 14-year old seeking an abortion in England finally caught legal attention. This study attempts to help define who these abortion seekers are. Questionnaires from 200 Irish abortion seeking women attending private Marie Stopes clinics in London and the British Pregnancy Advisory Services clinic in Liverpool between September 1988 and December 1990 were analyzed. Findings pertain to demographic characteristics, characteristics of first intercourse, family discussion of sexual activity, and contraceptive use. From this limited sample, it appears that Irish women are sexually reserved and without access to modern methods of birth control and abortion. Sex is associated with shame and guilt. 23% had intercourse before the age of 18 years and 42% after the age of 20. 76% were single and 16% were currently married. 95% were Catholic; 33% had been to church the preceding Sunday and 68% within the past month. Basic information about menstruation is also limited and procedures such as dilatation and curettage may be performed selectively. 28% of married women were uninformed about menstruation prior to its onset. Only 24% had been using birth control around the time of pregnancy. The reason for nonuse was frequently the unexpectedness of intercourse. 62% of adults and 66% of women believe in legalizing abortion in Ireland. British groups have tried to break through the abortion information ban by sending telephone numbers of abortion clinics to Irish firms for distribution to employees. On November 25, 1992, in the general election, there was approval of constitutional amendments guaranteeing the right to travel for abortions and to receive information on abortion access. The amendment to allow abortion to save the life of the mother was not accepted.

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

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

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

2017-01-01

ABSTRACT 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. PMID:28963175