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Blast performance is related to rock structure and strength, as well as to factors such as site geometry, drill patterns, explosives loading, firing sequences and delays.

Jan 1, 1986

The paper considers the factors that will control the importance and the nature of R & D required by the Australian mineral industry over the next decade. The process required to determine the appropriate priorities for research and how it must be managed is described. The work of the Australian Mineral Industries Research Association is used to illustrate this process.

Jan 1, 1986

? Hollow Stem Auger ? Drill Bits ? Leads/Torque Arm ? Hydraulic Gearbox ? Hydraulic Power Unit ? Grout Pump ? Crawler Crane

Jan 1, 1998

Samples weighing O·25 g are fused with 1 g potassium hydrogen sulphate, leached with 5 ml. of hydrochloric acid, and then diluted with another 5 ml. of acid. After settling, an aliquot of the clear solution is reduced with stannous chloride, and then a zinc dithiol solution is added to form a coloured tungsten complex which is extracted with petroleum spirit for comparison with standards.Concentrations down to 4 p.p.m. may be analysed at a rate of 100 determinations per man-day of 8 hr.

Jan 1, 1970

By R. A. Wood, R. I. Jaffee, H. R. Ogden, D. N. Williams

CERTAIN titanium alloys when quenched to retain the 0 phase at room temperature show extensive transformation of 0 to martensitic a during deformation. Alloys of this type are usually characterized by low tensile yield strength, a large spread between yield strength and ultimate strength, and high uniform elongation. A previous investigation of this phenomenon concluded that the principal contribution of the martensitic transformation was to increase the amount of deformation prior to fail-

Jan 1, 1964

By T. Egleston

THERE has always been a-theory among those working placer mines that gold is both found " rusty," and becomes so under treatment, by which they mean, not that gold becomes coated with oxide of gold, bat that it is either coated superficially or alloyed with sortie substanee 'which prevents the ,contact with mercury, and thus precludes the possibility of amalgamation. To such conditions of the

Jan 1, 1881

By G. W. Healy

The smelting of calcium carbide has always been plagued by eruptions, too often with serious injury y or loss of life. To find their causes, the author calculated an internal energy balance using 1992 data for CaC2 and CaO, and older data for the remaining items. The heat content of the charge, and that of the hot gases formed at the reduction temperature, showed that only a fraction of its heat content can be supplied by these gases. Laboratory data on the electrical resistivity of fine mixtures of coke and non-conductive solids were extrapolated to a commercial carbide charge, and then used to calculate the heat produced by current flowing through the mix from the electrode surface to the hearth, which, under favourable conditions, sufficed to bring the charge to 1900 K and higher, at which temperatures reduction could take place.

Jan 1, 1995

Perhaps, after years of concerted effort at a mineral prospect, your company has reached the stage of feasibility study. Detailed target investigations, drilling, bulk sampling, land acquisition, and engineering analyses are complete, and the deposit still remains an attractive investment possibility. Your company, after long study, decides to begin mine development-now, how do you convince lending institutions that your proposed operation will return their borrowed funds, plus interest, over the term of the loan?

Jan 12, 1978

By Meakins R. L, Talaska A, Kenny D, Haycraft J. A, Dickson B. L

A vehicle-mounted radiation detector interfaced to a microprocessor called PRAM (programmable radioactive analyser mobile) has been developed to provide grade control for selective mining of a soft rock uranium ore. The grade of ore over which the vehicle passes is determined and indicated by several coloured lights to a pegman who walks behind the vehicle. Coloured pegs are then laid out to mark the uranium grade ranges on the floor of the mine pit. Comparison between grade ranges determined by the PRAM and by prior drilling and downhole logging at the Yeelirrie deposit, Western Australia indicate good agreement. Use of the PRAM decreases the cost, manpower and time required to grade extensive areas of a mine pit floor.

Jan 1, 1982

By Michael Rieber

Capable of establishing a net present value of zero over a short period of time small mines, though not simply scalers of large operations, minimize market risks and reduce investment capital. Particularly now they are relevant to LDC development. Small mine concepts are reviewed with emphasis on sizing, speed, and LDC problems. The special problem of gold and the precious metals is examined with respect to mine evaluation. Small mine analysis is introduced with emphasis on the financial model including gold price forecast considerations.

Jan 1, 1987

By X. Wu, M. Karfakis, E. Topuz

The generalized ventilation network problems encompassing both natural and controlled splitting networks, is formulated using a nonlinear nonconvex programming model, which has not yet been solved satisfactorily. This paper presents a methodology which can deal with the problem. The proposed methodology converts the nonlinear problem into a linear problem, by using special ordered sets of variables, and optimizes it by a modified branch and bound technique. The global optimality of the methodology and its applicability to different cases are investigated

Jan 1, 1991

By Young-Dong Cho, Han-uk Lim, Bok-Ki Park, Sang-Eun Lee

Many methods and techniques have been developed to reduce ground vibrations. Some of them are an adoption of electric millisecond detonators with a sequential blasting machine and an improvement of initiating system with an adequate number of delay intevals.

Jan 1, 1995

[Appalachian Petroleum Section: Walter H. Chapman, chairman; Jean Freeland, first vice-chairman; John Galpin, second vice-chairman; Jack L. Trittipo, secretary-treasurer. Meets 4th Tues., Humphreys Restaurant, Charleston. Balcones Section: William E. Richards, chairman; William C. Miller, Jr., first vice-chairman; Brantley G. Myers, second vice-chairman; Harold Vagtborg, Jr., secretary-treasurer. Meets 4th Wed., Petroleum Center Club, San Antonio. Big Horn Basin Subsection: Donald G. Davis, chairman; B. E. Yester, vice-chairman; J. F. Keleher, vice-chairman; Samuel N. Conley, third vice-chairman; William O. Snyder, secretary; M. J. England, treasurer. Billings Petroleum Section: N. J. Matthews, chairman; Guy J. Lookabaugh, first vice-chairman; George O. Ellis, second vice-chairman; Robert L. Spottswood, secretary-treasurer. Meets 3rd Tues., Turf Penthouse.]

Jan 1, 1961

By G. Almgren

Swedish cut-and-fill mines are described with regard to location, production volumes, and grades. Development goals (such as higher productivity and better working conditions) are presented, and different methods of development, such as mechanization, new layouts, etc., are discussed. Development methods are described with examples from drilling, loading, haulage, and rock mechanics. Special attention is paid to filling techniques. Figures are given for productivity and relative costs.

Jan 1, 1977

By W. H. Pelton, P. G. Hallof

Outlining small pods of high-grade, massive sulfide, copper-zinc mineralization was the object of an intensive exploration program by Long Lac Mineral Exploration Ltd., near York Harbour, Newfoundland, Canada. Efforts to define the ore zones using surface dipole-dipole induced polarization techniques were not entirely successful due to the poor size-to-depth ratio of the targets and widespread disseminated mineralization. Additional information on the size and shape of the sulfide bodies was obtained by placing a current electrode directly within a mineralized drill intersection and systematically measuring the resultant potential on the ground surface. Some simple potential field sources were interpreted from the data and their validity has been shown by an extension to the underground workings.

Jan 1, 1973

[Appalachian Petroleum Section: James M. Kimbrough, chairman; John H. Adair, first vice-chairman; Walter L. Diddle, second vice-chairman; Byron M. Finch, secretary-treasurer. Balcones Section: Robert V. West, chairman; Frank W. Jessen, first vice-chairman; Zane V. Morgan, second vice-chairman; Brantley G. Myers, secretary-treasurer. Meets 4th Wed., Petroleum Club (San Antonio) or Terrace Dining Room (Austin) Billings Petroleum Section: Charles B. Evans, chairman; L. M. Lyon, first vice-chairman; Gordon E. Lansford, second vice-chairman; Fred. A. Haddenhorst, secretary-treasurer. Meets 3rd Tues., Billings Petroleum Club. California Coastal Section: Robert L. Richardson, chairman; David K. Hayward, first vice-chairman; W. Jackson Bransford, secretary; William N. Harwell, treasurer. Meets 3rd Thurs., Pierport Inn, Ventura. Caracas Petroleum Section: Edwin A. Moo re, chairman;. Jose Cirigliano, vice-chairman; Frank B. Davis, secretary; Robert N. Powers, treasurer. Meets 2nd Tues., Caracas Theater Club.]

Jan 1, 1961

By B. Y. Ekber, A. S. Gorbachev

The development of economically effective and safe methods of mining thick coal seams allow considerable coal reserves to be used as an energy resource all over the world.

Jan 1, 1979

By A. Pavlides

The purpose of this study is to compare estimation methods for lignite reserves at the Amyndeo mine and to provide a map of the estimated thickness of the coal seams. The reserves are first estimated with the method of Voronoi diagrams, using a group of mirror points to close the polygons around the boundaries of the mine. The second estimation method is based on Ordinary Kriging using the Spartan variogram model. Finally, the reserves are estimated by the mean lignite thickness value of the drill-hole data Two data sets are investigated. The first one corresponds to an exhausted part of the mine. The derived reserves estimates are compared with the actual data obtained by the Public Power Corporation (PPC) to validate the analysis. The second data set extends over the entire mine, and it is used to derive an approximate estimate of the total lignite reserves. A geostatistical analysis of the total layer thickness is performed. An interpolated kriging map of the total thickness variation is produced accompanied by a map of the kriging uncertainty.

Jan 1, 2008

By Li. S. D., R. X. Zhang, K. M. Li, Y. D. Zhang, Y. J. Hou, S. G. Li

A computer aided design software system for long range coal surface mine planning has been developed by the authors. The system is composed of two subsystems: a coal deposite sub- system and a long range mine planning system. The geological parameters are estimated and a grid model is formed, then a 3-D block model can be developed for mining design. The long range surface mine planning system is based on oriented graph simulation and combined approaches to seek for the optimal deign alternative. This mining model consists of a number of sub-models to realize mining design functions such as: calculation of mining volume and coal quality by graph scanning; determination of operational stripping ratio by interactive design; varification of annual coal production; delimitation and development of dumping site; optimization of material flow direction and volumes by Linear Programming; surface mine production scheduling by interactive iteration; etc. The software package was developed on PC computer 486. It features classified menu guide, module structure, figure and graph representation on the screen and flexible interactive functions. This system has been applied to an open cut coal mine and predicted functions have been obtained.

Jan 1, 1996

By M E. Malmstr÷m

Quantification of site-specific sulfide oxidation rates is crucial to accuracy of prediction of, for example, the environmental impact of a mine site. Sulfide oxidation reactions are reportedly increased by bacterial mediation; determination of abiotic and biotic weathering rates thus requires the establishment of sterile control samples. However, sterilisation often involves exposure of samples to extreme conditions that may alter the physical, chemical, or mineralogical characteristics of the tailings and hence affect element release rates. The impact of various sterilisation techniques, common and novel, on the element release rates from tailings from the Kristineberg site, northern Sweden, has been investigated. Batch weathering experiments indicated that the different methods of sterilisation (autoclaving, heat treatment, ethanol/heat treatment, application of antibiotics, rinsing with distilled water, and γ-radiation) did not greatly affect long-term element release rates. Long-term experiments (>30 days) are thus to be recommended for establishment of weathering rates. Sterilised and untreated control samples showed similar element release rates after ~100 days of experiments; possible explanations include that microbial oxidation is not important under our experimental conditions (Po2 = 0.2 atm, pH ~2.3, 22¦C, 0.01 M HNO3, no additional nutrients).

Jan 1, 2003