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Polymer mud system maintains high ROP in deep well
ROCK BREAKAGE:MACHINE EXCAVATION successfully drilled. A new analytical equation to predict the rate of salt creep into a wellbore is also presented. (Authors) 953127 Polymer mud system maintains high ROP in deep well J. D. Palm, Oil & Gas Journal, 92(43), 1994, pp 92-94. The use of a polymer mud system with low plastic viscosity to help reduce drilling time on a deep well in Oklahoma is described. An aggressive bit programme and a special mud system, which kept low-gravity solids to a minimum, maintained a high rate of penetration in the deeper sections of the well. Bit hydraulics are outlined and the polymer mud specifications are given. Drilling of the top and intermediate holes is discussed. (P.M.Taylor) 953128 Effects of exposure of aquatic snails to sublethal concentrations of waste drilling fluid J. A. Ekundayo & M. O. Benka-Coker, Environmental Monitoring & Assessment, 30(3), 1994, pp 291-297. Static bioassays were carried out using two aquatic snails
(Pilia sp. and Lani,ctes sp.) as test organisms in soft natural dilution water, with waste drilling fluid as the test material, at 28 _+ 2°C. Comparison of results for the control and different concentrations of the waste drilling fluid were made by means of the F-static method. The waste drilling fluid was practically non-toxic to the two aquatic snails. (Authors)
Blasting 953129 An approach to improve blasting efficiency in an iron ore mine M. M. Singh, R. B. Singh, P. Pal Roy, A. Bagchi & B. B. Dhar, International Journal of Surface Mining, Reclamation & Environment, 8(3), 1994, pp 87-93. This paper presents an approach to improve overall blasting efficiency in an iron ore mine. The problems existing in the mines were oversize fragmentation, severe backbreak, frequent secondary drilling and blasting operations, sloping bench faces and irregular bench profiles. Thorough analysis of the blasting practices and results was done in the search of key parameters affecting blasting efficiency. The parameters were burden, stemming length, delay period between the rows, placement of booster charge, booster ratio and firing pattern. Optimum blast geometry was evolved by making proper adjustments of the above parameters during trial blasts. (Authors) 953130 Assessing the effects of joint orientation and rock mass quafity on fragmentation and overbreak in tunnel Masting A. K. Chakraborty, J. L. Jethwa & A. G. Paithankar, Tunnelling & Underground Space Technology, 9(4), 1994, pp 471-482. It is well known that rock mass properties exert considerable influence on the process of fragmentation. Observations in a model study and field study using conventional bulk blasting were compared in order to determine the effects of rock mass quality and joint orientation on fragmentation and profile control in tunnel blasting. It was observed in the study that blast results such as average fragment size and depth and cross-sectional area of broken zone were considerably influenced by the joint orientation. Accordingly, it is concluded that larger-capacity loading equipment and deeper blast holes are required in formations with joint planes perpendicular to the tunnel axis. (from Authors)
121A
953131 Ground vibration assessment under varying circumstances in a limestone quarry in India P. K. Singh, P. Pal Roy & R. B. Singh, International Journal of Surface Mining, Reclamation & Environment, 8(3), 1994, pp 121-123. It is established that the ground vibration generated due to the detonation of commercial explosives depends on the direction of blast, charge per delay, geology, geology of the site and blast design parameters. This paper gives a detail understanding of the fact that physical and geometrical parameters are also important in association with blast design parameters. (from Authors)
Crushing and grinding 953132 In-pit crushing and conveying at Highland Valley Copper A. D. MacPhail & D. M. Richards, Mining Engineering, 46(10), 1994, pp 1186-1190. Highland Valley Copper currently mines two low-grade ore bodies, Lornex and Valley. The partnership was formed in 1986. As a cost reduction measure, it was decided to use an inpit crushing and conveying system to deliver the ore from the Valley Pit to the Lornex mill 3 km (1.8 miles) away and 175 m (575 ft) above the pit rim. The system uses two gyratory crushers that feed a series of conveyors to transport up to 130 kt/d (143 000 stpd) to the main stockpiles. This paper describes the performance of the in-pit crushing system as it is currently configured, as well as its evolution to date and future planned moves. (Authors) 953133 Research on wetting agent for water infusion of coal seams (in Chinese) Wang Huibin, Wang Yuandong & Lu Ping, Journal of China Coal Society, 19(2), 1994, pp 151-160. Prewetting of coal seams by water infusion is an essential measure for dust control at working faces. Adding of wetting agent is an important approach for improving water infusion. This paper discusses the function, effect, optimal concentration, its effect on floatation and selection of wetting agent for coal seam infusion. Some conclusions are obtained. (English summary)
Machine excavation 953134 Middicbalt Mine sires new Joy miner ANON, Coal, 99(10), 1994, pp 74,76-77. This article, part of a special report on the South African coal mining industry, gives details of the Middlebult mine and its developing technologies. A new machine for continuous mining, the largest of its kind, has been designed and developed at the mine. This JOY 12HM31 miner was developed as a response to deteriorating hard cutting conditions, high operational, maintenance and overhaul costs and excessive fine coal production. (S.E.Long) 953135 Development of vertical-horizontal shield machine H. Itoh, N. Kainuma, Y. Fukawa & K.-i. Kaneko, in:
Tunnelling and ground conditions. Prec. congress, Cairo, 1994, ed M.E.A. Salam, (Balkema), 1994, pp 355-362. A vertical-horizontal shield machine has been developed to carry out efficient excavation of shaft and adit tunnels deeper underground. The vertical-horizontal shield machine consists of a main shield for vertical excavation with a rotatable sphere incorporated in sub-shield for horizontal excavation.
(Pilia sp. and Lani,ctes sp.) as test organisms in soft natural dilution water, with waste drilling fluid as the test material, at 28 _+ 2°C. Comparison of results for the control and different concentrations of the waste drilling fluid were made by means of the F-static method. The waste drilling fluid was practically non-toxic to the two aquatic snails. (Authors)
Blasting 953129 An approach to improve blasting efficiency in an iron ore mine M. M. Singh, R. B. Singh, P. Pal Roy, A. Bagchi & B. B. Dhar, International Journal of Surface Mining, Reclamation & Environment, 8(3), 1994, pp 87-93. This paper presents an approach to improve overall blasting efficiency in an iron ore mine. The problems existing in the mines were oversize fragmentation, severe backbreak, frequent secondary drilling and blasting operations, sloping bench faces and irregular bench profiles. Thorough analysis of the blasting practices and results was done in the search of key parameters affecting blasting efficiency. The parameters were burden, stemming length, delay period between the rows, placement of booster charge, booster ratio and firing pattern. Optimum blast geometry was evolved by making proper adjustments of the above parameters during trial blasts. (Authors) 953130 Assessing the effects of joint orientation and rock mass quafity on fragmentation and overbreak in tunnel Masting A. K. Chakraborty, J. L. Jethwa & A. G. Paithankar, Tunnelling & Underground Space Technology, 9(4), 1994, pp 471-482. It is well known that rock mass properties exert considerable influence on the process of fragmentation. Observations in a model study and field study using conventional bulk blasting were compared in order to determine the effects of rock mass quality and joint orientation on fragmentation and profile control in tunnel blasting. It was observed in the study that blast results such as average fragment size and depth and cross-sectional area of broken zone were considerably influenced by the joint orientation. Accordingly, it is concluded that larger-capacity loading equipment and deeper blast holes are required in formations with joint planes perpendicular to the tunnel axis. (from Authors)
121A
953131 Ground vibration assessment under varying circumstances in a limestone quarry in India P. K. Singh, P. Pal Roy & R. B. Singh, International Journal of Surface Mining, Reclamation & Environment, 8(3), 1994, pp 121-123. It is established that the ground vibration generated due to the detonation of commercial explosives depends on the direction of blast, charge per delay, geology, geology of the site and blast design parameters. This paper gives a detail understanding of the fact that physical and geometrical parameters are also important in association with blast design parameters. (from Authors)
Crushing and grinding 953132 In-pit crushing and conveying at Highland Valley Copper A. D. MacPhail & D. M. Richards, Mining Engineering, 46(10), 1994, pp 1186-1190. Highland Valley Copper currently mines two low-grade ore bodies, Lornex and Valley. The partnership was formed in 1986. As a cost reduction measure, it was decided to use an inpit crushing and conveying system to deliver the ore from the Valley Pit to the Lornex mill 3 km (1.8 miles) away and 175 m (575 ft) above the pit rim. The system uses two gyratory crushers that feed a series of conveyors to transport up to 130 kt/d (143 000 stpd) to the main stockpiles. This paper describes the performance of the in-pit crushing system as it is currently configured, as well as its evolution to date and future planned moves. (Authors) 953133 Research on wetting agent for water infusion of coal seams (in Chinese) Wang Huibin, Wang Yuandong & Lu Ping, Journal of China Coal Society, 19(2), 1994, pp 151-160. Prewetting of coal seams by water infusion is an essential measure for dust control at working faces. Adding of wetting agent is an important approach for improving water infusion. This paper discusses the function, effect, optimal concentration, its effect on floatation and selection of wetting agent for coal seam infusion. Some conclusions are obtained. (English summary)
Machine excavation 953134 Middicbalt Mine sires new Joy miner ANON, Coal, 99(10), 1994, pp 74,76-77. This article, part of a special report on the South African coal mining industry, gives details of the Middlebult mine and its developing technologies. A new machine for continuous mining, the largest of its kind, has been designed and developed at the mine. This JOY 12HM31 miner was developed as a response to deteriorating hard cutting conditions, high operational, maintenance and overhaul costs and excessive fine coal production. (S.E.Long) 953135 Development of vertical-horizontal shield machine H. Itoh, N. Kainuma, Y. Fukawa & K.-i. Kaneko, in:
Tunnelling and ground conditions. Prec. congress, Cairo, 1994, ed M.E.A. Salam, (Balkema), 1994, pp 355-362. A vertical-horizontal shield machine has been developed to carry out efficient excavation of shaft and adit tunnels deeper underground. The vertical-horizontal shield machine consists of a main shield for vertical excavation with a rotatable sphere incorporated in sub-shield for horizontal excavation.