Texture analysis for comminution products characterization

371A uses an additional plug to move the explosive charge up from the weak zone to more competent rock above. Rock fall reduction of up to 88% is achieved. 916319 Vibration control in an openeast mine based on improved blast vibration predictors Pal Roy, P Min Sci Technol V12, N2, March 1991, P157-165 A number of structures (1 and 2 storey brick buildings, mud house, concrete wall) were erected at the edge of the working area of the West Mudidih open pit mine in Bihar, India. Vibrations due to rock blasting were monitored and used to test seven conventional and modified blast vibration predictors, including those of Ghosh-Daemen. A new model is developed as an improvement, which is simple to use and provides a better index of determination and improved charge/delay. 916320 Effects of some blast design parameters on ground vibrations at short scaled distances Taqieddin, S A; Ash, R L; Smith, N S; Brinkmann, J R Min Sci Technol V12, N2, March 1991, P167-178 Results of 135 test blasts in Jefferson City Formation layered dolomite with calcareous bonding have been analysed. Primer location, collar stemming, charge weight, and hole diameter were varied and effects on ground motion, air blast, and flyrock over small scaled distances examined. Borehole pressure is shown to be the major source of induced ground motion. If air blast is controlled, ground vibration remains at a low level. Air blast and fly rock effects due to collar priming are greater than those due to bottom priming. 916321 Blast design to improve fragmentation in a mismatched combination of drill diameter and depth in bedded rock Singh, M M; Singh, R B; Gupta, R N Min Sci Teclmol V12, N2, March 1991, P179-186 Blasting experiments at an opencast coal mine are described. Bench heights are 7m and 14m and hole diameter 250mm. Thickly bedded harder sandstones lie under softer rocks. Discontinuities were mapped to allow confinement of the explosive, as far as is possible, within the bedding planes. Most efficient breakage is found when the explosive is concentrated in the hard rock. Use of explosive at the bottom or inadequate supply to each layer results in the formation of boulders along the bedding plane.

916323 Separating explosive charges with air gaps to improve fragmentation whilst reducing explosive usage Rowlands, M D Proc 2nd Conference on Large Opeu Pit Mining, Latrohe Valley, 3-6 April 1989 P105-107. Publ Melbourne: AuslMM, 1989 Deck loading of explosive charges separated by air gaps was employed in order to maintain sufficient column height of explosives to ensure adequate fragmentation in hard near surface sandstone strata. Three different field trials, with two using two explosive charges separated by an air gap and the third with three charges separated by two air gaps, have been successfully conducted. Results are presented.

Crushing and grinding 916324 Computer simulation of the liberation process in coal crushing Misra, D D Proc 21st International Symposium on Applications of Computers and Operations Research in the Mineral Industry, Las Vegas, 27 Februar.V-2 March 1989 P826-830. Publ Littleton: AIME, 1989 A computer algorithm is described which takes into account the different breakage characteristics of the different density fractions fed to the crusher and the migration of material from one density fraction to another during the crushing process. It can be incorporated into existing computer programs having size distribution models. 916325 Texture analysis for comminution products characterization Bonifazi, G; Massacci, P Proc 21st International Symposium on Applications of Computers and Operations Research in the Mineral Industry, Las Vegas, 27 February-2 March 1989 P867-878. Publ Littleton: AIME, 1989 Control of products of comminution processes by textural analysis using image processing techniques is discussed. The method is based on analysis of grey level distribution of images recorded by television camera. No sample preparation is required. Algorithms have been developed to convert grey scale spatial dependence matrices into textural information. The technique is simple, non-invasive, and selective.

Machine excavation See also: 916505

916322 Assessment of cast blasting practices using monitoring techniques Danell, R E; Moxon, N T; Berndt, J R Proc 2nd Conference on Large Open Pit Mining, Latrobe Valley, 3-6 April 1989 P97-104. Publ Melbourne: AuslMM, 1989

916326 Machine development in roadway drivnge at the Konrad iron ore mine (In German) de Boer, H Gluckauf V127, N9/lO, May 1991, P376-383

Studies were conducted to quantify movement and timing of the cast blast using high speed cameras in conjunction with face and detonation markers. The motion of each maker can be examined frame by frame in a NAC Motion Analysis projector. Corrections for the camera angle to the face, camera shake, and assumptions that the motion is perpendicular to the face were used in data analysis. Details of the monitoring experiments and the obtained results are presented.

The old workings of the Konrad mine are under investigation as a possible radioactive waste repository. Two selective cut roadheaders were used to explore mine layout and possible storage volume. In middle reef oolite,petrofacial changes and fracturing necessitated expensive modifications to the machines to adapt to the new conditions. This allowed increased drivagc rates, up to 100m/day, and the abilityto cut rock with compressive strength up to 19MPa.

© 1991 Pergamon Press pie. Reproduction not permitted