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By Donald C. Rotherham

The Endako, British Columbia, deposit was initially discovered in 1927 by two local men, Charles H. Foote and Alf Lagdon, who were at that time on a hunting expedition. Four mineral claims were located to cover an area of quartz-molybdenite float that was centered on two small ridges. They subsequently uncovered a 0.5-m (1.6-ft) wide vein on which an inclined shaft was sunk to a depth of 8.3 m (27.2 ft) in 1934. Additionally, a short adit was driven to intersect another vein. Numerous trenches and small pits were also dug. Small test shipments of vein material from this early work were sent to G.S. Eldridge and Co. in Vancouver for metallurgical testing. A concentrate assaying 89.2% MoS, was produced with a recovery reported as 93.3%. The concentrate was essentially free of copper, arsenic, and phosphate. The property was examined by many geologists and engineers during 1934 to 1952, but the only work done was undertaken by the owners in order to maintain their claims in good standing. In 1952, Kennco Explorations (Canada) Ltd. carried out a limited program of bulldozer trenching, sampling, and geological mapping before relin- quishing their option. In 1956, American Standard Mines Ltd. acquired an option on the property, but no assessment work was apparently recorded and the property was allowed to lapse. The key claims were restaked in 1959 by C. Riley and H.T. James of Vancouver. The property was optioned from the new owners by Andrew Robertson in July 1961, and a small amount of trenching was conducted. Robertson, on behalf of his own company, R & P Metals Corp., reoptioned the property in January 1962. The initial results of this work were favorable and justified further exploration. The additional finances required to continue the program resulted in the formation of Endako Mines Ltd. (N.P.L.) on June 21, 1962. Field work by R & P Metals and the first Endako Mines exploration was directed by Bob Couts.

Jan 1, 1991

By Yong Jingrong

Based on the results of several test socketed piles in Sichuan, the mechanism of the deformation for a loaded socketed piles is investigated, and the concept of the socketed effect is proposed. The bearing capacity and settlement of socketed pile are controlled directly by socketed effect, that is an important mark different from the other types of cast-in-situ piles. According to the analysis of this effect and factors interferring it, their roles are discussed with the results of test piles. In order to increase the bearing capacity of piles, the ways and methods enhancing socketed effect are recommended.

Jan 1, 1991

By Hans-Werner Tonscheidt

Introduction The endeavours to mechanise the shaft sinking operations have led to the development of shaft boring using a V-Mole. The method implies competent ground and a pilot hole of sufficient verticality. This connects the top and the bottom of the shaft and serves for air ventilation and the transport of mullock. The shaft boring machine - nick name V-Mole - with a general pattern similar to a tunnel-borer reames the pilot hole to the designed diameter of the shaft. (Figure 1) The excavating of the rock, the removal of the mullock from the face and the lining of the shaft wall are done simultaneously. If they can be done also continuously this than creates a high potential of productivity. The verticality of the shaft can be garanteed due to the laser beam guided steering system. The diameter of the shaft is variable in steps of 0.5 m between 6.0 and 10 m in accordance with the need. It decides the capacity of the V-Mole to be applied. The depth of the shaft does not depend on the machine. It is practically unlimited as long as a suitable pilot hole is available. Up to 1988 almost 12.656 m of shaft have been drilled on 40 individual projects in Germany and the U.S.A. using a V-Mole. The rocks penetrated were Carboniferous sediments consisting of Sandstones, Shales, Conglomerates and Coal seams. The average uniaxial compressive strength was in the range of 300 - 700 Mpa with a maximum of 1700 Mpa in some singular sandstones.

Jan 1, 1991

By Jr. Wallace

This paper describes the importance of mine ventilation and air conditioning in the operation of a nuclear waste repository. It discusses the impact of ventilation on determining the number and size of shafts and access drifts to and within a repository horizon. The paper also describes the need to maintain separate ventilation systems for waste emplacement and construction operations. The requirement to have filtration capabilities for exhaust air from waste emplacement areas is discussed. Because radioactive high level waste will induce high temperatures in the emplacement drifts, the ability to cool an emplacement drift for re-entry requirements is important. The paper discusses strategies to cool an emplacement drift and the possibility of using continuous airflow to control temperatures in these drifts.

Jan 1, 1991

By G. S. Gupta

To predict the iron oxide concentration a mass transfer model has been developed for an Induction Smelting Process (ISP) in which self-fluxed composite pellets (made of iron ore, brown coal and lime) are melted in a single phase induction furnace in conjunction with top blown oxygen. Transient mass balance equation with complex boundary conditions has been worked out by adopting a relatively new approach known as the cell model approach. These equations have been solved numerically using finite difference technique to obtain the iron oxide concentration profile in the ISP. Numerical and experimental results obtained for iron oxide concentration show a reasonable agreement with each other.

Jan 1, 1991

By L. A. Vermeulen, C. P. Campbell, D. D. Howat

The production 01material liner than 75 µm in a number of open-circuit mills was investigated. The mils ranged from laboratory rod and ball mils treating a variety 01 ores to large industrial rod mils treating gold and copper ores. It was shown that the dependence on feed rate 01 the production 01 material liner than 751J.1T1 can be accurately described by a simple formula that was derived in previous work. In some 01 the systems reviewed, it proved possible to assess the feed rate 01 ore to the mil at which the rate 01 production 01 material finer than 75 µm can be maximized.

Jan 1, 1991

Longwalling has reached a high standard both in Germany and Australia and most improvements should be expected in planning, monitoring and control. Double drum shearer have electric drives to 1000 kW and automatic height control is under development. Conveyor pans to 40mm thickness and chains to 2300 kN breaking load are in use with controls for pretension and load compensation under test.Trends in support are towards two leg shields with loads to 3850 kN per leg and electrohydraulic controls. Expert systems have been devised for planning and diagnosis tasks. With increases in technical standards, staff qualification standards at rising too, drawing attention to training requirements for modem personnel.

Jan 1, 1991

By Jinrong Zhang

Major components of soil were tested for their ability to attenuate cyanide. Feldspar, kaolinite, plagioclase and bauxite are found to degrade cyanide at an appreciable amount mainly through adsorption. A soil near a mining site in northern Nevada was studied in detail using a tall column. Many species of cyanide were anlyzed to determine the mechanisms of the reactions of cyanide with soil. Volatilization, adsorption, oxidation, precipitation and complexing were quantitatively identified, being 5 to 10, 11.7, 4.2, 7.3 and 4 per cent of the total cyanide added, respectively. It is found that the oxidation of cyanide to cyanate is due to the catalytic effect of nickel and copper leached from the soil. Precipitation of metal-cyanide complexes occurred at low pH values.

Jan 1, 1991

By F. F. Peng

A unique collector dispersion techniques was developed and used to improve the flotation rate and recovery of coarser and ultrafine coal-rich particles in the froth flotation processes. In this novel collector dispersion method, the collector such as hydrocarbon-oil is gasified and transported by gas phase (air stream) into the pulp. In addition to the excellent mode of collector dispersion, the collector-encapsulated air bubbles are generated in the pulp. This approach alters the surface properties of air bubbles and provides the fast rate of flotation compared to that of direct liquid collector addition froth flotation. Using gasified kerosene as the collector, the effect of altering surface properties of bubbles on the recovery of larger and finer coal-rich particles of -1.7 mm (-12 mesh) and -600 µ m (-30 mesh) raw coal samples were studied. The Redstone seam coal obtained from Northern Central region of West Virginia was used in this work. The effect of particle size on oil-coated bubble flotation rate and recovery were also evaluated. The conventional froth flotation test with a liquid form of kerosene addition was also conducted for comparison purpose.

Jan 1, 1991

By Woodcock J. T, Rummel P. H, Sparrow G. J, MacRae C. M

An automated method, which is believed to be the fastest in the world and which can be used by mineralogically-untrained technical assistants, has been developed for the rapid location of native gold particles and other gold minerals down to 1 pm in size in ores, concentrates, and tailings using a scanning electron microscope. Searching of a 25 mm diameter polished block in 1 pm steps usually requires 3-4 h. Examples of the location of native gold and gold tellurides in drill core sections, in crushed ore samples and gravity and flotation concentrates, and in various metallurgical test products are given. The results have application in ore exploration, in guiding metallurgical test programmes, and in assessing metallurgical per- formance in testwork and in operating plants.

Jan 1, 1991

By James K. Gowans

The Red Dog Operation is located in northwestern Alaska at Latitude 68°, 100 miles north of the Arctic Circle and 50 miles inland from the Chukchi Sea. The orebody was acquired by the NANA Regional Corporation, (an Alaska Native Corporation established by the Alaska Native Claims Settlement Act of 1971), in 1980 in their land selection. In 1982 Cominco American and the NANA Corporation signed a development agreement and Cominco Alaska Inc., a wholly owned subsidiary of Cominco American, was formed to manage the Red Dog Project. An extensive exploration program in 1980 -1982 outlined a mineral inventory of 85 million tons, at a grade of 5.2% Pb, 17.1 % Zn, and 2.4 oz/ton Ag, which makes the Red Dog the second largest deposit ever discovered. Broken Hill, in Australia, is the only zinc orebody which was originally larger than Red Dog. The design of the facilities is to process 2.1 million tons of ore annually, which will produce 560,000 tons of zinc concentrate, 100,000 tons of lead concentrate and 50,000 tons of bulk lead/zinc concentrate.

Jan 1, 1991

By Johnson D. P, Beamish B. B

The northern Bowen Basin has a very large resource of coalseam methane gas-in-place - 136 TCF(7ohnson and White, 1988). The gas is pipeline quality, being 98-99 per cent methane with traces of carbon dioxide and higher hydrocarbons. The largest resource of natural gas within the coalseams of the northern Bowen Basin is contained in the Moranbah Coal Measures (75 per cent). The next most important resource is in the combined upper Fort Cooper (16 per cent) and Rangal (nine per cent) Coal Measures. The far northern parts of the basin have low gas contents due to the combined effects of limited extent of the coal measures, shallow depth and low rank. Reserves per well are more than double that of the best coalseam methane wells in any basin in the United States. In some areas of the Moranbah Coal Measures, the gas-in-place estimates exceed 225 million cubic metres per well (80-acre spacing). A distinction is made between resource base, as determined from this basin assessment, and the deliverability potential. Parameters used to estimate gas-in-place (coal area, thickness, density, rank and depth) can be adequately extrapolated from areas of high- to low- data density. Parameters affecting methane production (permeability, gas depletion factor and critical desorption pressure) cannot be generalised. Exploration and development programs must rapidly develop a predictive capability for these factors, on a local scale, through geological modelling and confirmation drilling.

Jan 1, 1991

By R. Mohr

Storm water runoff from mine facilities such as haul roads, waste disposal sites and ore bodies have become recognized as the primary facilities associated with non-point source drainage. Depending on the ore body, facility design and geographical setting, nonpoint source drainage can cause pollution impacts to local surface and ground water resources. Non-point source impacts from surface mine drainage have become an important regulatory issue for the mining industry. Implementing non-point source drainage control plans that prevent impacts to water resources can be accomplished cost-effectively with moderate labor requirements. Design considerations for plan development must incorporate parameters including contributing drainage area size, slope, flow velocity, vegetation characteristics and soil scour velocities. The success of non-point source drainage and erosion stabilization planning is based on implementing control measures that dissect drainage patterns, reduce flow velocities and disperse runoff towards sediment control sites. Interim and long-range drainage control measures should begin during exploration activities. Regulatory legislation addressing non-point source pollution sources was enacted as amendments to the Clean Water Act (CWA) in February 1987. The legislation required states to initiate non-point source pollution control programs.

Jan 1, 1991

By Leonard G. Austin

INTRODUCTION Run-of-mine (ROM) coal generally falls into two major groups: that from underground mining (continuous mining machines) and that from strip mining. Continuous miners produce a finer product and strip mining a coarser product that is crushed to produce the desired size. Further size reduction depends on the proposed use or uses for the coal. For example, for pulverized coal power plants as a rough general rule, the coal is ground or pulverized to 80% less than 200 mesh (0.075 mm) before it is blown into the boiler furnace as a coal-air suspension. For solvent-refined coal processes, the desired size is about <30 mesh (< 0.60 mm); in fluidized bed uses, the coal is typically < 8, in. (< 1.6 mm); for Lurgi pressure gasifiers, the desired size is 1 to 2% in. (25 to 63 mm). Coal preparation plants typically work with a coarse size fraction of 6X 1/14 in. (150X32 mm). The past decades has shown a steady increase in the tonnage of coal cleaned, 1 but it seems probable that the next decades will produce much wider applica- tion of deep coal cleaning before use and that the stages of crushing and pulverization from ROM coal to end use will be integrated with coal cleaning processes. Since different cleaning processes work better with different ranges of coal size and the degree of cleaning possible is intimately connected with the size of coal, a systems design engineer will need as much information as possible concerning the size distributions produced by different types of machines and how these can be modified by different ways of operating the machines. In general, the following questions will be of concern: 1.What type of crusher or grinder is best, or most satisfactory, for reducing a given feed size and type of coal to a desired product size? Frequently, the desired product is smaller than some nominal size, but with as few fines as possible, or the fraction in some size range has to be as high as possible. 2. How big does the machine have to be for a given throughput rate? 3. How much electrical energy (or its equivalent) is required per ton of product? 4. How does the size distribution vary with change in throughput rate, and is a control scheme necessary or desirable? 5. Can the size distribution be readily varied if desired? 6. What is the optimum way to operate a machine in a given system? This section will emphasize certain general principles which guide us in answering these questions. PARTICLE SIZING Since particle size and size distribution are the raw information with which we work, it is worthwhile to review the terminology used. In this regard, see

Jan 1, 1991

By Robert A. Haney, David J. Atchison, Kenneth G. Fields

Mining systems with greater than a 20-foot face advance (deep cut) have become popular due to their increased productivity and safety. The face dust collection system used in many of the mines employing the deep cut systems, incorporates a machine mounted dust collector with either a blowing or exhausting line brattice and a remote control operated continuous miner. In order to characterize and quantify the parameters used to control dust with these systems, the Dust Division conducted studies on four mining sections using continuous miners with deep cut mining systems. On each section, the dust control system incorporated line brattice with a machine mounted dust collector. The remote control made it possible for the continuous mining machine to advance further while permitting the operator to remain under supported roof and away from dust generated during mining. The purpose of these studies was to evaluate the effectiveness of deep cut mining systems using dust collectors to control respirable dust exposure. This paper summarizes the results of the studies conducted. At each mine face workers were sampled to determine their full-shift dust exposure. Additionally, fixed point dust samples were collected at various locations to determine relative concentrations of dust generated from mining. Air quantities were measured at each working place to determine the amount of air delivered to the face area. Evaluations were made by comparing worker exposures to respirable dust samples taken at appropriate locations upstream and downstream of the coal faced being mined. An estimate of the amount of the respirable dust being generated at the face during mining and the amount of respirable dust being removed by the dust collectors was made by balancing the air quantities and the dust concentrations immediately upstream and downstream of the coal face. Results of the studies showed that the dust control systems, were effective for controlling workers exposure to respirable dust. Dust collector efficiencies were determined to be approximately 85 percent. While the dust collectors were effective in removing respirable dust, the success of the systems with line brattice greater than twenty feet from the face, was dependent on the use of the remote control which permitted the continuous miner operator to remain out of the high concentration dust cloud in the working face. Dilution from intake air, combined with the dust collector efficiency, maintained exposure of other section workers below applicable standards.

Jan 1, 1991

By Lar Liljeblad

"As demands upon the earth&apos;s natural resources continue to grow, exploration companies, mining organizations and others face the problem of the need to tackle increasingly more difficult strata to open up new reserves. Innovations in materials technology and tool design have steadily improved this capability, but none perhaps so drastically as a recently introduced cemented carbide in which tool wear resistance and/or toughness can be tailored precisely to the user&apos;s drilling needs.Introduction Until about forty years ago, the bulk of rock-drilling operations had to be carried out with hardened steels. Short life between re-grinds was common especially in abrasive rock formations. Shortly after World War II, Sandvik, Sweden, pioneered the development of sintered (cemented) carbide-tipped steel tools as a means of improving drill tool life. The new material was a composite of tungsten carbide and cobalt, the latter acting as a &apos;cement&apos; to bind the wear-resistant carbide grains together, and the composite, in turn, was brazed to the steel. The immediate effect was a 100-fold increase in the service life of the tool.Intractable ProblemsWhile the carbide-tipped tools served the mining and quarrying industries admirably there were, nonetheless, some seemingly intractable limitations. The greater the wear resistance of the material - the quality for which it is selected - the more brittle it is. Also, rocks vary widely in hardness and abrasiveness and no single tool, either in terms of material or shape, meets every need. Specifically, for fast penetration of non-abrasive rock, toughness must be combined with a relatively sharp tool prome. Highly abrasive rock, on the other hand, demands a substantially broad area of extremely wear-resistant material on the tool if long bit life is to be assured. Between these extremes there are innumerable variations in rock"

Jan 1, 1991

By Winthrop F. Watts, Robert W. Waytulonis

During the 1980&apos;s. the Mine Safety and Health Administration (MSHA) proposed new regulations for the use of diesel equipment in underground coal mines, and the National Institute for Occupational Safety and Health (NIOSH) recommended that whole diesel exhaust be regarded as "a potential occupational carcinogen", and that reductions in exposure to exhaust pollutants would reduce excess risk. During the same time, the Bureau of Mines tested new emission control technology to minimize diesel emissions. The objectives of this paper are to discuss the major issues regarding diesel exhaust emissions. especially diesel particulate matter (DPM) , and to highlight emission controls that will be available. DPM is a potential health threat because it is respirable in size and is composed of nonvolatile carbon with adsorbed or condensed compounds. These compounds include potentially mutagenic or carcinogenic hydrocarbons such as polynuclear aromatic hydrocarbons and sulfates. DPM contributes to the degradation of air quality in mines with typical mean concentrations ranging from 0.2 to 1.0 mg/m3. In addition to adequate ventilation, control of DPM can be achieved by implemention of improved work practices, regularly scheduled engine maintenance, and emission controls.

Jan 1, 1991

By C. R. Rinschler, G. R. S. Smith

A high-strength, industrial-grade membrane filter- cloth capable of high flow rates and sub-micrometric particle retention has been developed. A filtration system using this filter- combined with special filtration techniques and using tubular-filters makes possible the filtration of many difficult-to-jilter slurries. Small, discrete, slowly-settling particles are formed into filter cakes that when pulsed of the membrane filter cloth do not redisperse but settle rapidly to form a dense filter under- flow. A positive separation of solids from liquids is obtained.

Jan 1, 1991

By John R. Marks

In April 1990, the Homestake Gold Mine embarked on a five year, $US 23 million underground drifting and drilling program to explore promising ore targets north of the current mine. This paper describes the ventilation and air-conditioning system that was installed for the 4m x 4m x 5.2 km (ultimately) drift, which is being driven at about 8m per day in 48OC (118.5 F) crystalline rock. Design parameters are described first. Differences in South African, Canadian and U.S. drift ventilation and civil tunneling techniques proved interesting. Details are then given on equipment selection, installation and performance. Costs are included. Special note is made of safety considerations for a long, dead-end drift.

Jan 1, 1991

By B. R. Broekman, D. W. Penman

Discussion by P.J Lloydt Broekman and Penman describe (J.S. Afr. Inst. Min. Metal., vol. 91, Aug. 1991, p. 261) the addition of sodium cyanide and zinc sulphate to the flotation feed at Prieska. They note that for &apos;safety sake, lime was added to the rod mil to raise the pH to 9,5&apos;, and that &apos;personnel working in the vicinity of the rod mil were required to wear gas masks&apos;. Author reply to P.J. Lloyd We thank Dr Lloyd for his interesting contribution. As he correctly points out, the Prieska float had run with cyanide solutions at pH values of 6,4. In fact, it ran safely for extended period with the pH slightly below 6.

Jan 1, 1991