Ore leaching in underground stopes

192A 913493 Approach for design of coal pillars in partial extraction coal mining panels with a consideration for roof-pillar-floor interaction Pytel, W M; Chugh, Y P; Pula, O Rock Mechanics Contributions and Challenges: Proc 31st US Symposium, Golden, 18-20 June 1990 PIOI-108. Publ Rotterdam: ,4 ,4 Balkema, 1990 Layout of partial extraction mines in seams with weak floor strata is discussed. Pillar design procedures are proposed which include pillar strength, bearing capacity of the floor. differential settlement of adjacent pillars, absolute settlement based on floor heave, surface subsidence, and roof-pillar-floor interaction. An approximate analytical model, SIU PANEL.2D, for analysis of roof-pillar-floor interaction and a general technique to estimate bearing capacity of a two layer foundation have been developed, which allow the proposed design method to be implemented. Two examples are presented. 913494 Strata control problems associated during extraction of developed pillars in thick seams by Blasting Gallery method Gupta, R N; Garg, A K; Mukherjee. K P; Singh, B Rock Mechanics Contributions and Challenges: Proc 31st US Symposium, Golden, 18-20 June 1990 P109-117. Publ Rotterdam: A A Balkema. 1990 Bord and pillar mining produces about 95% of India's underground mined coal. Every year about 100rot is sterilised in pillars. The Blasting Gallery (BG) method, developed at the Carmaux Colliery in France, is being tested in 2 Indian mines for pillar extraction by caving of 7-8m thick seams in a single lift. Strata deformation around the pillar and surface subsidence have been monitored and technico-economic analysis begun. Potential applications and areas where the BG method cannot be used are discussed. 913495 Determination of pillar strength by full scale pillar tests in the Laisvall mine Soder, P E; Krauland, N Strata Control in Deep Mines: Proc llth Plenary Scientific Session of the International Bureau of Strata Mechanics, World Mining Congress, Novosibirsk, 5-9 June 1989 P39-59. P,tbl Rotterdam: A A Balkema. 1990 Full scale tests were carried out on 9 pillars, with pillar width reduced in 6 steps of 0.gin in order to examine whether failure would occur in roof or floor strata (pillar punching) or in the pillar itself. Both types were seen. depending on the nature of roof strata. 2D finite element analysis was used to interpret results. A formula was developed for pillar strength in terms of uniaxial strength of rock mass. pillar length, and scale of measurement.

actual recovery point. Assessments of an alternative method of using predriven recovery rooms when longwall n'tining, in order to increase the productivity of the coal extraction process. are presented. 913497 Economics of thin seam plowing in the United States Merritt, W J Proc 1989 Multinational Conference on Mine Planning and Design, Lexington,23-26 May 1989 P125-133. Publ Lexington: OES Publications, 1989 The technological advances of Iongwall plow systems have attained a level where their manpower and other cost savings may be sufficient to turn a marginal or unprofitable continuous miner operation around. The determination of plow applicability requires a considerable amount of research, design, and planning. The economics of replacing continuous miners with a plow system is very site specific and depends on many interrelated variables. An overview into the economic processes required to make a decision to purchase and install a plow system is presented. 913498 Vertical crater retreat mining in the Sudbury basin Trotter, D Proc ! 989 Multinational Conference on Mine Planning and Design, Lexington,23-26 May 1989 PI35-142. Publ Lexington: OES Publications. 1989 Faced with rising costs and lower metal prices, several Ontario based metal sulphide mines have changed their method of mining to vertical crater retreat mining. This is a bulk mining method that utilizes large diameter holes and mines successive cuts remotely by blasting and cratering the bottom of the drill holes. The orebody is mined from the bottom up. Some experimental work and the benefits in improved safety of this method are demonstrated and discussed. 913499 Ore leaching in underground stopes Boreck, D L; Lutzens, W W; Speirer, R A Proc 1989 Multinational Conference on Mine Planning and Design, Lexington,23-26 May 1989 PI43-153. Publ Lexington: OES Publications, 1989 Research is currently being conducted in order to determine the feasibility of incorporating in situ stope leaching into active underground metal/nonmetal mines. The technique proposes to recover metals from ore by creating underground rubblized stopes, leaching the stopes underground for metal recovery, and collecting and processing the metal bearing solution. A summary of the preliminary stope design and solution management research is presented.

913496 Productivity and equipment removal enhancement using predriven Iongwall recovery rooms Bauer, E R: Listak, J M Proc 1989 Multinational Conference on Mine Planning and Design, Lexington,23-26 May 1989 PI19-124. Publ Lexington: OES Publications, 1989

913500 Need for high rates of development of roadways in coal mines - a new approach Lama, R D; Marshall, P Minerals, Materials and Industry, Proc 14th Congress of the Council of Mining and Metallurgical Institutions, Edinburgh, 2-6 July 1990 P497-508. Publ IMM: London, 1990

Moving the equipment of a long,'all face from one panel to the next is a critical efficiency issue to any longwall operation. Move times are a function of face width and panel length (distance of move), and the amount of equipment installed on the new face prior to start-up of the actual move. Conventional methods of Iongwall equipment recovery involve preparation for equipment removal a considerable distance from the

The rate of development of roadways in coal mines for Iongwall panels in particular, and inseam development in general, is becoming critical because of high levels of production of Iongwall operations. Existing roadway development technology with cyclic cutting and bolting systems utilizing continuous miners and roadheaders is not adequate to meet future requirements. New conceptual models to meet these demands

~ 1991 Pergamon Press plc. Reproduction not permitted