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REINFORCEMENT:GENERAL
After vertical excavation, the sphere rotates 90° to start the sub-shield. This newly developed machine is capable of excavating shafts and adits continuously using only a single machine. This report describes the vertical-horizontal shield machine, an implementation example of the right-angled rotating shield machine, the first sphere shield machine, and the vertical- horizontal shield machine planned to be the second machine. (Authors) 953136 Optimizing track-loader matching D. Gave & W. Morgan, Mining Engineering, 46(10), 1994, pp 1179-1185. In truck and shovel operations, productivity and cost per ton are influenced by the system matching choice. Optimization involves a balance of the size and number of trucks, the size and type of loading tool and the projected material conditions and haul roads. Caterpillar has updated its Fleet Production and Cost program so miners can more easily look at matching choices and optimize on the variable they choose. This paper introduces the Fleet Production and Cost program. It then demonstrates its capabilities with examples of optimization. As haul conditions change (haul length, grade or rolling resistance), there may be need to adjust the number of trucks to maintain the optimum fleet match. Fleet Production and Cost is a tool that can be used to optimize the truck-loader match. (Authors) 953137 Resistance of particulate media to excavation: application to bucket loading A. Hemami, S. Goulet & M. Aubertin, International Journal of Surface Mining, Reclamation & Environment, 8(3), 1994, pp 125-129. In excavation of particulate media the resistive force for cutting through, or digging, must be overcome by the cutting tool. A knowledge about this force is essential for designing the cutting tools and the excavating machinery. Such a knowledge becomes quite important for automating the operation of these machines. It may be used for feedback purposes in order to monitor and adjust the motion of the excavating tool. In this article the excavation force on a loader bucket during loading is considered. After a preliminary analysis of the various components of this force, its variation in the course of a desired motion of the bucket is determined and is graphically illustrated. (Authors) 953138 Distance learning R. Byles, New Civil Engineer (NCE), 1098, 1994, pp 26-27. What is believed to be the first unmanned, remote-controlled fleet of earthmoving plant has been used to shift and landscape volcanic lava and debris engulfing villages at the foot of the active Mount Unzen Fugen-dake volcano near Nagasaki on the Japanese island of Kyushu. This report briefly outlines the machinery and montoring systems employed, including the satellite global positioning system used to provide drivers (positioned 2km away from the site) with the precise locations of each earthmover. The fleet can be operated conventionally but is intended for use, in unmanned mode, on similarly hazardous projects in the future. (S.E.Long)
Hardness, abrasion and wear 953139 Computer simulation of dlamond-wire cutting of hard and abrasive rock A. Bortolussi, R. Ciccu, P. P. Manca & G. Massacci, Transactions - Institution of Mining & Metallurgy, Section A, 103(May-Aug), 1994, pp A124-A128.
The use of diamond-wire cutting technologies to obtain wellshaped blocks with high recovery is widespread in modern stone quarries. Tool performance and the unit cost of cutting depend on a number of operational variables (peripheral velocity, pull-back force, water injection rate, angles of the sections of wire outside the rock) as well as on the geometric features of the cut itself (area and shape). A computer program aimed at handling a problem of this complexity has been developed and tested. (from Authors)
ROCK AND SOIL REINFORCEMENT AND SUPPORT General 953140 Basics of paste backfill systems F. W. Brackebusch, Mining Engineering, 46(10), 1994, pp 1175-1178. Paste backfill is a pumpable, flowable, non-Newtonian fluid consisting generally of mine tailings and cement. Paste is prepared from dilute slurries of tailings. This is done by dewatering the slurries with conventional thickening or filtering. Backfill with a paste consistency is prepared by mixing dewatered tailings with cement and water to obtain the desired consistency of medium slump concrete. The paste is pumped with concrete pumps over relatively long (1 km or 0.6 mile) horizontal distances. More commonly, though, it flows by gravity down a mine shaft and then horizontally to the void being filled. Alternatively, cement can be added near the end of the pipeline. A certain proportion of fine particles ( < 20 tun (< 625 mesh) must be present in pastes but particles of aggregate can be added without significantly affecting the flow characteristics. Relatively small amounts of cement (3% to 5%) produce stiff backfill material 1.5 to 3.5 MPa (217 to 507 psi). The advantages of paste backfill in a mining operation include reduced mine dewatering, labor and materials savings, reduced tailings impoundment requirements, good support properties and reduced spills underground. Paste technology can be used for surface or underground placement of railings. (from Author) 953141 Torsional strength analysis of powered support (in Chinese) Wang Benrni, Journal of China Coal Society, 19(2), 1994, pp 207-211. In the design of shield support, it is necessary to calculate the torsional strength of the debris shield, the front and rear linkage when the canopy has offset loading, and when the debris shield is in torsion. The author derives a virtual system of debris shield and the front and rear linkage. Based on the normal method for solving static indetermination problems, the author established a general formula for solving distribution of moment between the front and rear linkage by using Castigliano theory to co-ordinate deformation. (English summary)
953142 Simulation and optimum design of locating dimensions of shield support balance ram On Chinese) Wang Guobiao & Gao Rong, Journal of China Coal Society, 19(2), 1994, pp 195-206. The balance ram is a key component of a two-leg shield support. It is usually damaged in operation. This paper presents a theory of load-carrying capability area of a shield support, using a 2-leg shield support as an example. Computer simulation, optimum design and a model test for finding optimal locating dimensions of the balance ram are made. The results show that increased dimension of the upper joint or decreased dimension of the low joint of the balance
REINFORCEMENT:GENERAL
After vertical excavation, the sphere rotates 90° to start the sub-shield. This newly developed machine is capable of excavating shafts and adits continuously using only a single machine. This report describes the vertical-horizontal shield machine, an implementation example of the right-angled rotating shield machine, the first sphere shield machine, and the vertical- horizontal shield machine planned to be the second machine. (Authors) 953136 Optimizing track-loader matching D. Gave & W. Morgan, Mining Engineering, 46(10), 1994, pp 1179-1185. In truck and shovel operations, productivity and cost per ton are influenced by the system matching choice. Optimization involves a balance of the size and number of trucks, the size and type of loading tool and the projected material conditions and haul roads. Caterpillar has updated its Fleet Production and Cost program so miners can more easily look at matching choices and optimize on the variable they choose. This paper introduces the Fleet Production and Cost program. It then demonstrates its capabilities with examples of optimization. As haul conditions change (haul length, grade or rolling resistance), there may be need to adjust the number of trucks to maintain the optimum fleet match. Fleet Production and Cost is a tool that can be used to optimize the truck-loader match. (Authors) 953137 Resistance of particulate media to excavation: application to bucket loading A. Hemami, S. Goulet & M. Aubertin, International Journal of Surface Mining, Reclamation & Environment, 8(3), 1994, pp 125-129. In excavation of particulate media the resistive force for cutting through, or digging, must be overcome by the cutting tool. A knowledge about this force is essential for designing the cutting tools and the excavating machinery. Such a knowledge becomes quite important for automating the operation of these machines. It may be used for feedback purposes in order to monitor and adjust the motion of the excavating tool. In this article the excavation force on a loader bucket during loading is considered. After a preliminary analysis of the various components of this force, its variation in the course of a desired motion of the bucket is determined and is graphically illustrated. (Authors) 953138 Distance learning R. Byles, New Civil Engineer (NCE), 1098, 1994, pp 26-27. What is believed to be the first unmanned, remote-controlled fleet of earthmoving plant has been used to shift and landscape volcanic lava and debris engulfing villages at the foot of the active Mount Unzen Fugen-dake volcano near Nagasaki on the Japanese island of Kyushu. This report briefly outlines the machinery and montoring systems employed, including the satellite global positioning system used to provide drivers (positioned 2km away from the site) with the precise locations of each earthmover. The fleet can be operated conventionally but is intended for use, in unmanned mode, on similarly hazardous projects in the future. (S.E.Long)
Hardness, abrasion and wear 953139 Computer simulation of dlamond-wire cutting of hard and abrasive rock A. Bortolussi, R. Ciccu, P. P. Manca & G. Massacci, Transactions - Institution of Mining & Metallurgy, Section A, 103(May-Aug), 1994, pp A124-A128.
The use of diamond-wire cutting technologies to obtain wellshaped blocks with high recovery is widespread in modern stone quarries. Tool performance and the unit cost of cutting depend on a number of operational variables (peripheral velocity, pull-back force, water injection rate, angles of the sections of wire outside the rock) as well as on the geometric features of the cut itself (area and shape). A computer program aimed at handling a problem of this complexity has been developed and tested. (from Authors)
ROCK AND SOIL REINFORCEMENT AND SUPPORT General 953140 Basics of paste backfill systems F. W. Brackebusch, Mining Engineering, 46(10), 1994, pp 1175-1178. Paste backfill is a pumpable, flowable, non-Newtonian fluid consisting generally of mine tailings and cement. Paste is prepared from dilute slurries of tailings. This is done by dewatering the slurries with conventional thickening or filtering. Backfill with a paste consistency is prepared by mixing dewatered tailings with cement and water to obtain the desired consistency of medium slump concrete. The paste is pumped with concrete pumps over relatively long (1 km or 0.6 mile) horizontal distances. More commonly, though, it flows by gravity down a mine shaft and then horizontally to the void being filled. Alternatively, cement can be added near the end of the pipeline. A certain proportion of fine particles ( < 20 tun (< 625 mesh) must be present in pastes but particles of aggregate can be added without significantly affecting the flow characteristics. Relatively small amounts of cement (3% to 5%) produce stiff backfill material 1.5 to 3.5 MPa (217 to 507 psi). The advantages of paste backfill in a mining operation include reduced mine dewatering, labor and materials savings, reduced tailings impoundment requirements, good support properties and reduced spills underground. Paste technology can be used for surface or underground placement of railings. (from Author) 953141 Torsional strength analysis of powered support (in Chinese) Wang Benrni, Journal of China Coal Society, 19(2), 1994, pp 207-211. In the design of shield support, it is necessary to calculate the torsional strength of the debris shield, the front and rear linkage when the canopy has offset loading, and when the debris shield is in torsion. The author derives a virtual system of debris shield and the front and rear linkage. Based on the normal method for solving static indetermination problems, the author established a general formula for solving distribution of moment between the front and rear linkage by using Castigliano theory to co-ordinate deformation. (English summary)
953142 Simulation and optimum design of locating dimensions of shield support balance ram On Chinese) Wang Guobiao & Gao Rong, Journal of China Coal Society, 19(2), 1994, pp 195-206. The balance ram is a key component of a two-leg shield support. It is usually damaged in operation. This paper presents a theory of load-carrying capability area of a shield support, using a 2-leg shield support as an example. Computer simulation, optimum design and a model test for finding optimal locating dimensions of the balance ram are made. The results show that increased dimension of the upper joint or decreased dimension of the low joint of the balance