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By S. F. Walsh

The San Manuel Oxide Pit is located within the subsidence boundaries of Magma Copper Company's block caving operation. Ground conditions offer a constant blasting challenge and vary from hard, competent crystalline rock to widely spaced fracturing in a sedimentary conglomerate. A successful drilling and blasting program has undergone several changes since mining commenced in 1985 and continues to be developed. This paper discusses the site specific progress made with the drilling and blasting program from selection of feasibility parameters to current practice. Topics discussed include controlled blasting, use Of high energy blasting agents, charge decking, blast casting, as well as standard drill and blast techniques.

Jan 1, 1988

The problem of spontaneous combustion has long exercised the minds of Mining Engineers. The idea of inertising an area with a non combustible gas has seemed to be an attractive way to overcome the problem. Various agents have been tried but nitrogen has particular attractions and advantages. Britain adopted the idea from the German industry and found that it was particularly suitable for the conditions in British Mines. Over 8 years much development work has been done and specialist equipment has been developed as the requirements came to be better identified with experience. There is a continuing programme of innovation and the technique can be further developed in the future as a means of protecting the very heavy investments which are being made in today's large capacity, heavily capitalised faces.

Jan 1, 1988

Mount Isa Mines Ltd. annually extracts 5.6 million tonnes of copper ore from the 1100 Orebody. All production is by longhole open stoping, with an increasing emphasis on pillar recovery. Drilling and blasting prac- tices have been modified to allow more efficient pillar extraction, with the evolution of a "core and shell" approach. Blast design occurs at the stope design stage, while individual blast preparation is based on detailed ring plans. A programme of blasting research involving surface and under- ground vibration monitoring and fragmentation assessment has been car- ried out in conjunction with production personnel. Drilling and blasting practice in the orebody must continue to evolve with continued research, to suit changing conditions and take advantage of new technology.

Jan 1, 1988

By Sullivan T. D

The Lochiel Deposit is a large occurrence of soft brown coal about 130 km north of Adelaide. The deposit is undergoing continued evalua- tion of which an integral part was the excavation of a Trial Pit. The Trial Pit was deemed necessary to demonstrate that the deposit may be mined efficiently by draglines and the particular emphasis was on the geotech- nical and hydrogeological aspects of what may be termed difficult mining conditions. The dewatering of the Trial Pit was commenced in September 1986. After considerable planning and excavation was successfully completed in May 1987. The project is unique in terms of its size and technical com- plexity. It entailed excavation of over 230,000 m3 of overburden to an overall depth of 36 metres. The excavated material was utilised for experimentation in a Trial Dump. Included in the Trial Pit design were several novel techniques includ- ing depressurisation drains to improve mining conditions in soil strength materials and the use of vacuum to aid dewatering.

Jan 1, 1988

The evaluation programme and procedures develop- ed for Saindak porphyry copper-gold-silver- molybdenum deposits located in an isolated area in an extremely and region of Baluchistan are described in detail. Due to its isol .ted location, far removed from supply centres, harsh climate, paucity of water and non-availability of even unskilled labour, Saindak presented problems for which no ready made solution exist- ed. It is hoped that this Paper may be of some value to those in the LDCs who may wish to undertake similar ventures.

Jan 1, 1988

By Moore R. F, Macias L. F

The Filbara region of northwestern Western Australia contains several known occurrences of mafic/ultramafic rock assemblages which may host platinum group element (POE) mineralisation. This paper deals with occurrences at Munni Munni and Andover. The Munni Munni complex is of particular interest because it is known to contain PGE mineralisation and is currently undergoing active exploration. The US/Australia Joint Scanner Project of October 1985 collected airborne scanner data for the BMR over Munni Munni. Such an ultramafic-mafic complex had not been previously researched with advanced remote sensing instrumentation. Extensive investigation of data from the NSOO1 (Thematic Mapper Simulator) scanner resulted in successful differentiation of gabbroic and ultramafic rocks, and also subdivision within the ultramafies. Similar differentiation could not be achieved using conventional Landsat MSS imagery and aerial photography. Encouraged by those results and in support of BMR field research into the mafic-ultramafic suites of the region, data from the Landsat Thematic Mapper (TM) instrument were investigated to attempt differentiation of the ultramafic and mafic rocks in the Andover complex some 50 km to the northeast of Munni Munni.

Jan 1, 1988

By N. A. Vatolin, L. I. Leontjev, S. V. Shavrin

The ever growing interest to the complex iron ores may be attributed to possible production of the naturally alloyed metals and the efficient recovery of the associated elements. However, the conventional technique for complex ore processing is complicated and in some cases even impossible. A pyrometallurgical benefiation of such ores without melted slag formation has been advanced. A version of the technique assumes pellet production with metal coagulated within a slag shell on grinding the pellets, the metal phase is mechanically separated from the slag shell. The technique has been run up with ferro chromo nickel, high-titanium, high-magnesia, alumina phosphorus ores and concentrates. Another version of the pyrometallurgical benefication without melted slag formation in a rotary kiln has been developed from the schemes for processing red mud of alumina manufacture and high-titanium concentrates. Means have been put up to improve schemes available for lex iron ore processing with primary emphasis on material pretreatment before blast furnace and steelmaking processes. Vanadium-bearing titanomagnetite conentrate oxidized pellets possess low strength at reduction. The technique suggested for pelletizing in the controlled atmosphere improves the afore said pellet metallurgical properties. Prodution of metallized pellets in a conveyor roasting machine holds considerable promise for blast furnace and steelmaking processes. In processing the high-sulphur iron ores still another technique is proposed to roast the fluxed pellets with 95% and more desulphuration.

Jan 1, 1988

Opencast blasting is notoriously subject to variable blasting conditions, some of which are related to changes in ground conditions and some to human and equipment factors. As drilling and blasting constitute a high proportion of working costs, control in this area is crucial for good management. During a recent exercise, wireline logging of blastholes was shown to have the potential to provide invaluable data for optimising blasting control and design. The paper reports on the exercise undertaken, showing that serious misconceptions as to the borehole diameters, explosive densities and posi- tions of decking were quickly corrected using the method. Potential use in blast design is discussed, as are the cost implications.

Jan 1, 1988

By E W. Kohler

Geophysical wireline logging of blastholes provides useful geological data and has considerable potential to improve overall blasting control and costs. This paper uses case histories to show how logging techniques have highlighted certain problems, and discusses the various in-hole tools available. In particular, the issue of the effects of hole diameter on explosive column height,and the importance of this when deck charging is addressed. The suitability and cost-effectiveness of currently available logging technology to the wide range of blasting applications is discussed.

Jan 1, 1988

By K. Sadrnezhaad

Industrial and experimental induction furnaces are used for melting various types of iron ingots, returned scraps and DRI sponge pellets to produce high purity cast-iron and steel heats. The lowest consumption of the electrical energy is determined for continuous feeding operation to be 0.3 KWH/Kg for production of cast-iron in 1.5-ton industrial furnace and 0.45 KWH/Kg for production of steel in 25-Kg experimental furnace. The optimum feeding rate for lowest energy consumption is obtained to be 12.5 grams per second for continuous feeding of DRI in 25-Kg induction furnace. Similar measurements show that the optimum size of the DRI pellets is around 8 millimeter.

Jan 1, 1988

By P. Louis

Although cobalt is known and used for its hardness and wear resistance, ductile cobalt can be obtained by electrolysis in chloride solutions, under the following conditions : pH : 1.5 - 2, Co++ : 30 - 60 g/l, current density : 100 - 500 A/m2, temperature 40 - 70°C. No explanation was found for the ductility of the deposit under these conditions. Indeed the ductile P (FCC) cobalt and the hydrogen contents in the cobalt deposits are nearly the same as those obtained in a sulfate media, which gives brittle depo¬sits under equivalent electrolysis conditions. Malleable cobalt sheets can be easily obtained under the proposed conditions which could lead to new applications for cobalt.

Jan 1, 1988

By B. J. Moore

This publication contains analyses and related source data for 191 natural gas samples from 22 states and 1 foreign country. Of the total samples, 182 were collected during calendar year 1987. The remainder were collected earlier, but releases granting permission to publish were not received before 1987. All samples were obtained and analyzed as part of Bureau of Mines investigations of the occurrences of helium in natural gases of countries with free market economies. This survey has been conducted since 1917. The analyses published herein were made by mass spectrometer and chromatograph.

Jan 1, 1988

By D. Lessard, S. Nantel

"Surface crown pillars are important Canadian,mining structures. Mines operating in the Canadian Shield usually have several, forming a first line of protection from surface elements.Detailed technical information from twenty-four Canadian hard rock mines show that the deposits dip steeply and are generally either single or multiple veins. Considerable overburden usually cap the deposits. The rock mass is often altered and intersected by important discontinuities.The designs for these types of pillars lack basic data and are based on experience rather than a scientific approach. Regardless of the competence of the rock mass, the surface crown-pillar thickness to width ratios (an unscientific design tool used by the industry) are usually less than five. Rock bolting is, in almost every case, used as a support measure. However, there are many openings neither backfilled nor monitored.The characteristics of openings with surface crown pillars are also examined."

Jan 1, 1988

By Kovscek P. D, Thimons E. D

The Bureau of Mines equipped a longwall shearer with a water- jet-assisted cutting system and measured dust levels during the cutting of a simulated coal block. The block was cut dry, at a conventional water spray pressure of 1 MPa and with water-jet-assisted cutting pressures ranging from 7 to 40 MPa. At water pressures of 20 MPa and higher, dust concentrations were reduced by as much as 85 % via water-jet-assisted cutting in comparison with conventional water sprays. This reduction was achieved without any increase in the water flow rate.

Jan 1, 1988

By W. E. Cobb

Mining companies, as developers of natural resources, are being forced to deal with the potential long-term liabilities of past, present, and future mining operations. As discussed in a previous paper (Cobb, et al., 1987), these liabilities can include solid waste disposal corrective action programs (state or federal actions), Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA), (Superfund) (state or federal actions), or natural resource damage claims (typically filed by state agencies and provisions specified in CERCLA). These potential liabilities are very real, and should dramatically impact the way a company views its exploration and development programs, and operating mines.

Jan 1, 1988

By A. Galibois, R. Singhal

"This paper highlights some of the potential application areas of knowledge-based systems in the mining industry. The basic theoretical principles associated with knowledge-based systems are discussed and the justification for mining applications is given. The paper concludes with a brief description of a prototype knowledge-based system applied to scraper selection that was developed at Université Laval on a LISP machine. IntroductionThe beginning of Artificial Intelligence coincided with the conception and development of the first computer systems some thirty years ago. At that time researchers were euphoric about the possibility of modelling the human reasoning process. Soon, however, they discovered that the combinatorial aspect of the set of possible solutions to a particular problem did not permit an in-depth evaluation.In the mid-60s researchers started to look at the heuristic approach because it was more suited to human behaviour with its congnitive abilities (i.e. representing, reasoning, problem solving and advising). The heuristic approach allows possible results rather than exact solutions and it is more rapid and cost effective than the exhaustive combinatorial analysis. The heuristic approach did allow some noticeable progress in the seventies with the development of the first expert system called MYCIN with the objective of diagnosing blood infection diseases."

Jan 1, 1988

By David G. Chedgy, Edward A. Zawadzki, Robert D. Stoessner

Extensive research and testing in commercial facilities has clearly demonstrated that heavy medium cyclones are the most effective process for cleaning a 0.6 x 0.15mm (28 x 100 Mesh) coal at low separating gravities, less than 1.35. This paper describes testing performed to deter- mine system characteristics at these lower gravities and the type of circuitry required to maximize performance. The results of these studies include both pilot and commercial scale tests of cleaning 0.6 x 015mm (28 x100M) coal.

Jan 1, 1988

By P. J. Bethell

This paper reviews current fine coal cleaning circuitry, including water washing cyclones, tabling and froth flotation. It goes on to examine possible future beneficiation based on emerging technologies. Circuits considered include those incorporating spirals, fine heavy medium cycloning, hydrosizers and column flotation.

Jan 1, 1988

By Brouwer G, Shaw J

As South African gold mines go deeper, and improved and more uniform working condi- tions are required, ever larger amounts of refrigeration are needed. At the same time new and more suitable cooling equipment is becoming available for use with new mining layouts as well as on existing shaft systems. The advent of the large diameter rotor screw compressor has meant that there is now a machine available with great flexibility in performance and construction for efficient underground use. The first installation using this type of machine is described.

Jan 1, 1988

By D. M. Hausen

Multiple drill sections through many of the numerous breccia pipes in the American Eagle copper deposit at Copper Creek, Arizona, have been evaluated by means of alteration and geochemical data. Contoured plots indicate vertically plunging, concentric, cylindrical shells of alteration and mineralized rock that are similar in structure, geometry, magnitude and petrology to the San Manuel-Kalamazoo Deposit, located about 14 miles to the southwest. Both deposits are similar in dimension and consist of multiple, irregular, rod-shaped injections of porphyry into a granodiorite host. Analogous to the San Manuel-Kalamazoo Deposit, most of the porphyry plugs are oriented parallel to the cylindrical axis of the "ore shell". A continuously mineralized, elliptical shell, inferred from deep drilling, is capped by a flatter zone of copper mineralization. Above this flat zone, copper-bearing fluids were channeled upward along conduits that correspond with quartz-sericite "breccia pipes". At depth, zones of sericite and K-feldspar alteration products exhibit conformable relationships with the copper deposition. A "bullet-shaped" ore shell, with a nearly vertical axis, is proposed to explain the conformable zones of altered and mineralized rock. The "nose" or top of the "bullet" is 1800 to 2300 feet below the surface, and structurally controlled in part by steeply dipping Hi and ENE faults. If correct, this model suggests that the vertical ore shell may extend to great depth.

Jan 1, 1988