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Regional aspects of mining-induced seismicity: theoretical and management considerations
227A Quicksand inflow disturbed shaft sinking at Bogdanka. Due to water influx at levels from 585 to 588m and from 600 to 70Ore, freezing was used during sinking. Freezing was associated with rock swelling, which in some cases damaged shaft linings. Additional measures were adopted for lining reinforcement.
846190 Weighting of the seam ahead of the face and its influence on the choice of mining technique (In Polish) Major, M Przegl Gorn 1/40, N1, Jan 1984, P1-6 846191 Recurrence of coal outbursts (In Polish) Szuscik, W Przegl Corn V40, N1, Jan 1984, P6-11 Laboratory tests on coal specimens under stress conditions simulating those in situ are reported, in order to assess the likelihood of the recurrence of outburst phenomena.
846192 Investigation of stress distribution and basic gas parameters in coal seams liable to outbursts (In Polish) Swidzinski, A Przegl Gorn V40. NI, Jan 1984, PII-19 846193 Example of a safe method for a Iongwall face to approach old workings under conditions of high risk of outbursts (In Polish) Marcela, E Przegl Gorn V39, N7-8, July-Aug 1983, P293-301 An example is presented of mining operations aimed at complete extraction of a seam under conditions of severe outburst hazard caused by the presence of a thick seam lying at depth beneath the unmined remains of neighbouring seams.
846194 Geophysical control of the process of water infusion into the rock mass used to reduce the liability to outbursts (in Polish) Dubinski, J; Szot, M Przegl Gorn V39, N7-8. July-Aug 1983, P301-307 846195 Behaviour of the rock mass in the underground gasification of coal (In Polish) Synowiec. L Przegl Gorn V39. N7-8, July-Aug 1983, P307-310 The effect of underground gasification on the overburden and on the surface is examined. The stress on surrounding strata during gasification can give rise to surface disturbances, whilst falls from the roof can affect the operation of the gas producer.
846196 Chemical disintegration of the coal mass at the 17/D/502 face of Nowy Wirek Colliery (In Polish) Pawlak, J; Sanetra, A Przegl Gorn V40. N3, March 1984, P83-86 Investigations into the application of methanol to decrease coal strength have been carried out by the Polish Central Mining Institute. Laboratory tests and field tests at Nowy Wirek Colliery on a face saturated with an aqueous solution of methanol have shown a considerable decrease in energy consumption during winning and a simultaneous increase in the rate of advance.
846197 Reduced outllmrst hazard by driving in previously de-gassed zone (In Russian) Fominykh, E I Stuikittnoe Strait NIO. Oct 1983, P14-15 Prior de-gassing lowers the inherent gas to a safe level in the drivage zone, and is achieved by drilling 10-15m beyond the roadway contour and carrying out a gas drainage operation over a period of 6-12 months. Experience at Lenin Colliery is recounted, where drainage was promoted by the use of hydraulic fracturing. Gas formation in boreholes was tested every 4-5m during the subsequent heading operation to check on outburst susceptibility. Only in 2 cases out of 150 tests were outburst hazards diagnosed and these were caused by feeders induced by hydraulic fracturing. Auth.
846198 Outburst prevention when opening up Karaganda coal seams (In Russian) Eralin. N E" Antonov. A V Shakhtnoe Strait NIl. Nor 1983. P28-29 Water infusion has been used to prevent outbursts during working of a particularly outburst-prone seam at the Lenin Colliery, USSR. The seam was sampled for moisture every 4m of advance. It was found that when the coal had adsorbed sufficient infusion water to increase moisture content to 5°~, it could be considered safe from outburst hazard. 846199
Analysis of stoping sequence and support requirements in a high-stress environment - ZCCM, Mufulira Division Russell, F M; Armstrong, D R M; Talbot, R Trans lnst Min Metall (Sect A Min ind) V93. Jan 1984, PAl-A9 For ten years part of the western section of Mufulira was mined without major problems. The area, which was overlain by a river, was mined by post-sandfill stoping methods. In 1973 and 1974 rock bursts occurred. A geotechnical analysis was carried out with the use of a mining simulation program, MSIM3D, which indicated that a change in stoping sequence was required, together with rock support. Stoping was resumed in the area, but in 1977 more rock bursts occurred and a more detailed investigation was initiated. The analyses were again carried out with MSIM3D, with modified input data. The results that were obtained indicated that mining in this area would always be subject to high stress and that subsidence beneath the stream with ingress of water into the workings was not impossible. It was decided to divert the stream and resort to a total extraction method of mining, without post-sandfill and with extensive support of development. This has been carried out over the past five years with success, some 6000000t having been extracted with a minimum of rock burst activity. The paper has also been published in 'Rockbursts: prediction and control' (London: IMM, 1983).
846200 Regional aspects of mining-induced seismicity: theoretical and management considerations Dempster. E L; Tyser, J A: Wagner, H Trans lnst Min Metall (Sect A Min lnd) V93, Jan 1984, PA 17-A27 Differences in seismicity in the major gold-mining districts are discussed. It is shown that on a regional scale seismicity is related to the mining-induced energy changes, but that the pattern of seismicity is governed by geological structures. The differences in the nature of the rock burst problem are illustrated by examples from two major gold mines. At Blyvooruitzicht gold mine. which operates in a relatively unfaulted mining district, the rock burst hazard is closely related to the stoping
228A geometry, whereas at the Vaal Reefs gold-mining complex the rockburst problem is closely linked to the geological structure. Examples are given of how mine management deals with the rockburst problem on these two mines. This paper has also been published in 'Rockbursts: prediction and control" (London: IMM, 1983).
846201 Assessment of floor stability during steep seam mining (In Russian) Frumkin, R A Ugol N6, June 1983. P11-14 A statistical method of predicting floor stability in steep seams has been developed at the Donbass mines, USSR. The method uses a number of factors to forecast the floor properties including compressive strength and lithology. The system has been used on many working faces in the Donbass and an accuracy of 92.8 to 96.1% is claimed.
846202 Considerations in the design of Iongwall mining systems Barozak, T M; Goode, C A In: State-of-the-Art of Ground Control in Longwali Mining and Mining Subsidence P39-50. Publ New York. AIME, 1982 The principal criteria in the design and operation of longwall mining systems are examined: economic considerations. geological considerations, panel design and environmental considerations, operational considerations, and production limitations.
846203 Geotechnical information applied to mine design Farmer, I W In: State-of-the-Art of Ground Control in Longwall Mining and Mining Subsidence P51-57. Publ New York. AIME, 1982 Case histories are introduced to illustrate how an understanding of the mechanics of deformation of mine structures associated with longwail layouts can be used to improve stability. Particular examples include: ( I ) deformations associated with longwall caving, (2) the effect of support pressure on roof deformation above a longwail face, (3) the effect of pack design on longwall access road closure and (4) the effect of rock deformation characteristics on floor heave.
846204 Multiple seam mine design Haycocks, C; Karmis, M; Ehgartner, B In: State-of-the-Art of Ground Control in Longwall Mining and Mining Subsidence P59-65. Publ New York. AIME, 1982 Examines the interaction effects between mining operations developed on different levels of contiguously placed bedded deposits. Analysis of field data reveals 4 major classes of ground control mechanism: pillar load transfer, arching, subsidence and shear plane development. Longwall mining interactions are considered in particular.
846205 Mining a steeply dipping coal seam in the United States by Iongwali Wisecarver, D W; Reynolds, J F In: State-of-the-Art of Ground Control in Longwall Mining and Mining Subsidence P67-73. Publ New York: AIME. 1982 Case study of the Snowmass Mine, Colorado, USA, where longwall mining was introduced to work a steeply dipping seam. This is the first attempt to do this in the USA.
846206 Review of progress with Iongwail mine design and layout Whittaker. B N In: State-of-the-Art of Groand Control in Longwall Mining and Mining Subsidence P77-84. Publ New York: AIME. 1982 846207 Pillar stability in Iongwall mining Wilson, A H In: State-of-the-Art of Ground Control in Longwali Mining and Mining Subsidence P85-95. Publ New York: AIME. 1982 A set of formulae which allows the calculation of the minimum pillar widths for roadway protection has been developed Although to a large extent built up from concepts difficult to prove beyond doubt, the overall deductions do fit the observed facts. The formulae have already been successfully used for the calculation of the widths of long continuous pillars, but their application to small pillars associated with multi-entry systems is also shown to be possible, leading to possible explanations of failures which have occurred in practice. Auth.
846208 Rock mechanics instrumentation and monitoring for ground control around Iongwall panels Lu, P H In: State-of-the-Art of Groand Control in Longwall Mining and Mining Subsidence P159-166. Publ New York. AIME. 1982 In order to design or select the optimum mine structure or system, realistic and precise values of design parameters must be determined in situ by measuring ground pressure, mining induced load transfer, and strata movement, as well as by determining deformation moduli and rock strengths. These measurements can be made with simple, inexpensive instruments: hydraulic borehole pressure cells, automatic recording convergence meters, automatic recording multiple-anchorpoint extensometers, and hydraulic pressure recorders.
8462O9 Evaluation of stresses in linings of shafts in composite constructions (In German) Klein, J In: Rock Mechanics: Caverns and Pressure Shafts (papers to the ISRM Symposium, Aachen, 26-28 May 1982) ~ , P623630. Publ Rotterdam: A. A. Balkema. 1982 846210 Origin of rocklmrsts Cook. N G W In: Rockbursts: Prediction and Control (papers to the Symposium, London, 20 October 1983) P I-9. Publ London: IMM, 1983 Practical observations of fracture zones near Iongwall stopes have been considered together with applicable theoretical and experimental work in order to produce a model of the fracture zone. The model is given in terms of 3 types of fractures: inclined shear fractures, cleavage fractures and vertical shear fractures. The last of these is considered the most likely candidate for the origin of rock bursts.
846211 Rockburst hazard and the fight for its alleviation in South African gold mines Salamon, M D G In: Rockbursts: Prediction and Control (papers to the Symposium, London, 20 October 1983)P11-36. Publ London: IMM, ]983
846190 Weighting of the seam ahead of the face and its influence on the choice of mining technique (In Polish) Major, M Przegl Gorn 1/40, N1, Jan 1984, P1-6 846191 Recurrence of coal outbursts (In Polish) Szuscik, W Przegl Corn V40, N1, Jan 1984, P6-11 Laboratory tests on coal specimens under stress conditions simulating those in situ are reported, in order to assess the likelihood of the recurrence of outburst phenomena.
846192 Investigation of stress distribution and basic gas parameters in coal seams liable to outbursts (In Polish) Swidzinski, A Przegl Gorn V40. NI, Jan 1984, PII-19 846193 Example of a safe method for a Iongwall face to approach old workings under conditions of high risk of outbursts (In Polish) Marcela, E Przegl Gorn V39, N7-8, July-Aug 1983, P293-301 An example is presented of mining operations aimed at complete extraction of a seam under conditions of severe outburst hazard caused by the presence of a thick seam lying at depth beneath the unmined remains of neighbouring seams.
846194 Geophysical control of the process of water infusion into the rock mass used to reduce the liability to outbursts (in Polish) Dubinski, J; Szot, M Przegl Gorn V39, N7-8. July-Aug 1983, P301-307 846195 Behaviour of the rock mass in the underground gasification of coal (In Polish) Synowiec. L Przegl Gorn V39. N7-8, July-Aug 1983, P307-310 The effect of underground gasification on the overburden and on the surface is examined. The stress on surrounding strata during gasification can give rise to surface disturbances, whilst falls from the roof can affect the operation of the gas producer.
846196 Chemical disintegration of the coal mass at the 17/D/502 face of Nowy Wirek Colliery (In Polish) Pawlak, J; Sanetra, A Przegl Gorn V40. N3, March 1984, P83-86 Investigations into the application of methanol to decrease coal strength have been carried out by the Polish Central Mining Institute. Laboratory tests and field tests at Nowy Wirek Colliery on a face saturated with an aqueous solution of methanol have shown a considerable decrease in energy consumption during winning and a simultaneous increase in the rate of advance.
846197 Reduced outllmrst hazard by driving in previously de-gassed zone (In Russian) Fominykh, E I Stuikittnoe Strait NIO. Oct 1983, P14-15 Prior de-gassing lowers the inherent gas to a safe level in the drivage zone, and is achieved by drilling 10-15m beyond the roadway contour and carrying out a gas drainage operation over a period of 6-12 months. Experience at Lenin Colliery is recounted, where drainage was promoted by the use of hydraulic fracturing. Gas formation in boreholes was tested every 4-5m during the subsequent heading operation to check on outburst susceptibility. Only in 2 cases out of 150 tests were outburst hazards diagnosed and these were caused by feeders induced by hydraulic fracturing. Auth.
846198 Outburst prevention when opening up Karaganda coal seams (In Russian) Eralin. N E" Antonov. A V Shakhtnoe Strait NIl. Nor 1983. P28-29 Water infusion has been used to prevent outbursts during working of a particularly outburst-prone seam at the Lenin Colliery, USSR. The seam was sampled for moisture every 4m of advance. It was found that when the coal had adsorbed sufficient infusion water to increase moisture content to 5°~, it could be considered safe from outburst hazard. 846199
Analysis of stoping sequence and support requirements in a high-stress environment - ZCCM, Mufulira Division Russell, F M; Armstrong, D R M; Talbot, R Trans lnst Min Metall (Sect A Min ind) V93. Jan 1984, PAl-A9 For ten years part of the western section of Mufulira was mined without major problems. The area, which was overlain by a river, was mined by post-sandfill stoping methods. In 1973 and 1974 rock bursts occurred. A geotechnical analysis was carried out with the use of a mining simulation program, MSIM3D, which indicated that a change in stoping sequence was required, together with rock support. Stoping was resumed in the area, but in 1977 more rock bursts occurred and a more detailed investigation was initiated. The analyses were again carried out with MSIM3D, with modified input data. The results that were obtained indicated that mining in this area would always be subject to high stress and that subsidence beneath the stream with ingress of water into the workings was not impossible. It was decided to divert the stream and resort to a total extraction method of mining, without post-sandfill and with extensive support of development. This has been carried out over the past five years with success, some 6000000t having been extracted with a minimum of rock burst activity. The paper has also been published in 'Rockbursts: prediction and control' (London: IMM, 1983).
846200 Regional aspects of mining-induced seismicity: theoretical and management considerations Dempster. E L; Tyser, J A: Wagner, H Trans lnst Min Metall (Sect A Min lnd) V93, Jan 1984, PA 17-A27 Differences in seismicity in the major gold-mining districts are discussed. It is shown that on a regional scale seismicity is related to the mining-induced energy changes, but that the pattern of seismicity is governed by geological structures. The differences in the nature of the rock burst problem are illustrated by examples from two major gold mines. At Blyvooruitzicht gold mine. which operates in a relatively unfaulted mining district, the rock burst hazard is closely related to the stoping
228A geometry, whereas at the Vaal Reefs gold-mining complex the rockburst problem is closely linked to the geological structure. Examples are given of how mine management deals with the rockburst problem on these two mines. This paper has also been published in 'Rockbursts: prediction and control" (London: IMM, 1983).
846201 Assessment of floor stability during steep seam mining (In Russian) Frumkin, R A Ugol N6, June 1983. P11-14 A statistical method of predicting floor stability in steep seams has been developed at the Donbass mines, USSR. The method uses a number of factors to forecast the floor properties including compressive strength and lithology. The system has been used on many working faces in the Donbass and an accuracy of 92.8 to 96.1% is claimed.
846202 Considerations in the design of Iongwall mining systems Barozak, T M; Goode, C A In: State-of-the-Art of Ground Control in Longwali Mining and Mining Subsidence P39-50. Publ New York. AIME, 1982 The principal criteria in the design and operation of longwall mining systems are examined: economic considerations. geological considerations, panel design and environmental considerations, operational considerations, and production limitations.
846203 Geotechnical information applied to mine design Farmer, I W In: State-of-the-Art of Ground Control in Longwall Mining and Mining Subsidence P51-57. Publ New York. AIME, 1982 Case histories are introduced to illustrate how an understanding of the mechanics of deformation of mine structures associated with longwail layouts can be used to improve stability. Particular examples include: ( I ) deformations associated with longwall caving, (2) the effect of support pressure on roof deformation above a longwail face, (3) the effect of pack design on longwall access road closure and (4) the effect of rock deformation characteristics on floor heave.
846204 Multiple seam mine design Haycocks, C; Karmis, M; Ehgartner, B In: State-of-the-Art of Ground Control in Longwall Mining and Mining Subsidence P59-65. Publ New York. AIME, 1982 Examines the interaction effects between mining operations developed on different levels of contiguously placed bedded deposits. Analysis of field data reveals 4 major classes of ground control mechanism: pillar load transfer, arching, subsidence and shear plane development. Longwall mining interactions are considered in particular.
846205 Mining a steeply dipping coal seam in the United States by Iongwali Wisecarver, D W; Reynolds, J F In: State-of-the-Art of Ground Control in Longwall Mining and Mining Subsidence P67-73. Publ New York: AIME. 1982 Case study of the Snowmass Mine, Colorado, USA, where longwall mining was introduced to work a steeply dipping seam. This is the first attempt to do this in the USA.
846206 Review of progress with Iongwail mine design and layout Whittaker. B N In: State-of-the-Art of Groand Control in Longwall Mining and Mining Subsidence P77-84. Publ New York: AIME. 1982 846207 Pillar stability in Iongwall mining Wilson, A H In: State-of-the-Art of Ground Control in Longwali Mining and Mining Subsidence P85-95. Publ New York: AIME. 1982 A set of formulae which allows the calculation of the minimum pillar widths for roadway protection has been developed Although to a large extent built up from concepts difficult to prove beyond doubt, the overall deductions do fit the observed facts. The formulae have already been successfully used for the calculation of the widths of long continuous pillars, but their application to small pillars associated with multi-entry systems is also shown to be possible, leading to possible explanations of failures which have occurred in practice. Auth.
846208 Rock mechanics instrumentation and monitoring for ground control around Iongwall panels Lu, P H In: State-of-the-Art of Groand Control in Longwall Mining and Mining Subsidence P159-166. Publ New York. AIME. 1982 In order to design or select the optimum mine structure or system, realistic and precise values of design parameters must be determined in situ by measuring ground pressure, mining induced load transfer, and strata movement, as well as by determining deformation moduli and rock strengths. These measurements can be made with simple, inexpensive instruments: hydraulic borehole pressure cells, automatic recording convergence meters, automatic recording multiple-anchorpoint extensometers, and hydraulic pressure recorders.
8462O9 Evaluation of stresses in linings of shafts in composite constructions (In German) Klein, J In: Rock Mechanics: Caverns and Pressure Shafts (papers to the ISRM Symposium, Aachen, 26-28 May 1982) ~ , P623630. Publ Rotterdam: A. A. Balkema. 1982 846210 Origin of rocklmrsts Cook. N G W In: Rockbursts: Prediction and Control (papers to the Symposium, London, 20 October 1983) P I-9. Publ London: IMM, 1983 Practical observations of fracture zones near Iongwall stopes have been considered together with applicable theoretical and experimental work in order to produce a model of the fracture zone. The model is given in terms of 3 types of fractures: inclined shear fractures, cleavage fractures and vertical shear fractures. The last of these is considered the most likely candidate for the origin of rock bursts.
846211 Rockburst hazard and the fight for its alleviation in South African gold mines Salamon, M D G In: Rockbursts: Prediction and Control (papers to the Symposium, London, 20 October 1983)P11-36. Publ London: IMM, ]983