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By L. W. Ashton

Geochemical exploration guidelines were developed from a study of 460 rock chip samples collected at nine disseminated gold deposits in Nevada. Obtaining high grade Au samples is difficult because gold content is extremely variable, even over 8 m (25 ft) distances. For reconnaissance sampling, pathfinder elements are reliable indicators with threshold values of 100 ppm As, 1 ppm Hg, and 50 ppm Sb. Arsenic is the most reliable of the three elements, being significantly enriched in all deposits. If the pathfinder threshold levels are reached with low Au content, more samples should be collected. Successful disseminated gold exploration requires large numbers of samples.

Jan 1, 1990

By R. A. Matuszak

Throughout the history of power excavating machines, engineers have continuously tried to shape the main drive speed- torque characteristics to provide an optimum from each main motion. Selection of prime mover for the various motions has been the subject of many engineering studies and most forms of energy conversion have been tried. A new form of electrical power conversion looms on the horizon as the most optimum yet. Controlled frequency operation of a squirrel cage induction motor increases the reliability of the most reliable form of energy conversion (electrical) found thus far, and improves the performance characteristics.

Jan 1, 1979

By Scott Stebbins

Cost estimating and economic evaluation software provide evaluators with the ability to predict the profit potentials associated with mine design alternatives even during project exploration and prefeasibility. Examining a multitude of development alternatives early on serves to identify aspects critical to profitability and to increase the reliability of economic projections. A case history illustrates how Sherpa Cost Estimating Software, when used in conjunction with Apex Software for Economic Evaluation, significantly enhances an evaluator's ability to examine design alternatives in a timely and reliable manner. The costs and economic impacts associated with various access routes, production rates, equipment mixes, and stoping methods are projected.

Jan 1, 2002

The most appropriate technology needs to be applied to premining geological investigations to achieve reliable data for predictions of geological conditions ahead of mining. The paper describes the application of various investigatory techniques in BHP's Illawarra Collieries which are used to provide reliable assessments of structure, the nature of the coal and surrounding strata,, and the fluids contained in the strata. The techniques used include surface seismic, in-seam seismic, borehole drilling, electromagnetic and aeromagnetic surveys, hydrogeological investigations and in-mine mapping. The results of various case studies are presented as examples of the application of techniques.

Jan 1, 1988

By X. Yang, G. D. Zhai

The prop is the most important part to ensure the proper functioning of hydraulic support. When the hydraulic support is impacted by the roof, the prop is prone to extrusion deformation, expansion, and even bursting. In order to study the stress on a doubly-telescopic hydraulic support prop under impact load, an impact simulation was carried out based on the drop weight method. First, the impact model of the hydraulic system of the prop was established in AMESim software and the dynamic response curves of the bottom and middle cylinder of the prop obtained. Then, according to the conservation of energy, the pressure formulaes in the hydraulic cylinder of the prop under impact load were derived and verified by the AMESim simulation results, and the maximum pressure on the inner surface of the hydraulic cylinder of the prop obtained. Lastly, the transient dynamic simulation of a hydraulic support prop was carried out in ANSYS Workbench software, and cloud diagrams of stress and deformation of the prop obtained using Workbench simulation. The AMESim simulation process describes the change in fluid pressure in the prop, and the pressure formulae can be used to estimate the internal pressure of the prop under impact load. The finite element analysis results show that the stress of the middle hydraulic cylinder is much greater than that on the bottom hydraulic cylinder under impact load, which can provide a reference for prop design.

Jul 2, 2022

By C Fearon

This paper discusses the implementation of an underground rail haulage system during a major expansion of the Olympic Dam mine in 1998. The factors affecting the selection of rail haulage are discussed and details are provided on the rail system, which is designed to transport more than 10.5 million tonnes per annum (Mtpa). The reliability of the system during commissioning is discussed, including the decision to manufacture a ædummyÆ locomotive in order to keep the system operational. Finally, reliability improvements made both during and after commissioning are discussed with comments provided on the effectiveness of the system as it operates today.

Jan 1, 2005

By J. S. Dunning

The Bureau of Mines investigated a series of Fe-Al-Mo alloys strengthened by ZrC (zirconium carbide) precipitates as chromium-free substitutes for stainless steels. Melting and fabrication methods were devised, and the effects of minor additions of columbium (niobium) and cerium on the mechanical properties and oxidation resistance were determined. Zirconium carbides could not be con-trolled reliably to produce fine precipitate dispersions. A more reliable carbide strengthening mechanism is required if the high-temperature strengths of types 304 and 316 stainless steels are to be duplicated. Workability and oxidation resistance of the alloy series were excellent.

Jan 1, 1982

By C. B. Queja

Flexible synthetic membrane liners have become a standard facet to copper and gold heap leach pad design. While gold heap leach operations have utilized most types of synthetic liners, copper leach operations have commonly only been lined with polyethylene. The objective of this study was to determine if there are any chemical reasons why other synthetic membrane types could not be used to line a copper heap leach facility. With engineered consideration, the flexible membrane liner under the ore pile serves two purposes. The first provides a near impermeable boundary which aides greatly in the collection of the metal laden process solution. The second advantage to the flexible membrane is the almost non-permeable barrier to benefit increased environmental awareness that has led to an increase in solution containment technology. The Environmental Protection Agency (EPA) has developed a compatibility test for solutions and membrane liners. The EPA Method 9090 is intended for use in determining the chemical effects of a solution on the physical properties of the flexible membrane liner material intended to contain them. Data from these tests would assist in deciding whether a given liner material is acceptable for the intended application.

Jan 1, 1995

By R Lau

The fire safety design for road tunnels includes the following aspects: active systems, passive provisions and operational procedures. The active systems include the smoke control system, fire suppression system, detection system and fire fighter’s assistance systems. Passive provisions include escape passages, fire separation and fire resistance systems. The operational procedures refer to fire fighter access, reporting and alerts, evacuation processes and crowd control.Currently, these systems are typically designed by different designers or teams. These systems are intended to work together in a coordinated manner to provide the desired safety outcome. However, in practice, this is not always happening. The fire engineering process is supposed to bring together all these aspects and arrive at an integrated safety system. The fi re engineering process in practice is not integrating the design with the practice or reality and is thus arriving at less than desirably efficient safety systems.The example of design inputs shows how disconnected each system design basis is. The smoke control system design is based on the design fire size. The performance of the smoke control system is to achieve a smoke free environment for a defined space for a particular fire size – the design fire. The fire suppression system – most commonly sprinklers or deluge systems, is designed according to codes and to achieve a certain water discharge rate. The fire detection system is designed to detect temperature rise/rate of rise and perhaps density of smoke. Fire separation is determined to provide a certain period of service – mostly for structural elements. Escape route size and location is determined mostly by code compliance. Evacuation procedures are determined by Authority operational requirements rather than human behaviour.To arrive at an integrated fire safety system, the design basis and performances must be coordinated. An approach using fire scenarios would ensure all systems are designed to a common performance requirement. This paper will discuss how the current design approach outcomes compared with a fire scenario approach. More effective and efficient fire safety systems would require the stake holders to understand the implication of this approach and to embrace this through the fire engineering process.

Mar 8, 2011

There is a strong demand for nickel metal due to quick development of stainless steel and new electrical materials, most of which is extracted from sulfide resources, resulting in a serious depletion of sulfide resources. Therefore, more attentions have been paying to extracting nickel from nickel laterite, which accounts for some 50% of total nickel metal production. In this paper prereducing?magnetic separation?reduction smelting process is developed to manufacture ferronickel rom two types of nickel laterite DN and GN, assaying 1.42% 1.83% Ni and 49.09% 26.08%Fetotal, respectively. Mineralogy of two types of nickel laterite was determined and optimization of process parameters was conducted to manufacture ferronickel. Prereduction?magnetic concentration process is used to upgrade low grade nickel laterite firstly, two kinds of Ni-Fe concentrates being prepared of DN assaying 2.26% Ni and 69.45% Fetotal and GN containing 2.76% Ni and 38.00% Fetotal. Finally, two types of ferronickel were produced by reduction smelting of prereduced concentrates DN and GN, DN and GN ferronickel contains 2.97% Ni and 6.58%Ni, 89.25%Fetotal and 89.95%Fetotal, respectively. The total recoveries of Ni and Fe of the two ferronickel are beyond 90% and 80%, respectively. There is significant difference in grade of magnetic concentrates and ferronickel between DN and GN laterite due to their different mineralogy, the former belongs to limonitic laterite and the latter saponite one. There are some advantages for this process to manufacture ferronickel from nickel laterite, including effectively upgrading low grade nickel laterite by prereducing?magnetic separation technique, higher throughput and lower energy available for reduction smelting section due to some 40% gangue being rejected in pre-upgrading section, and much less metallurgical coke consumption by using non-coking coal as reductant for prereducing?magnetic separation?smelting process.

Jan 1, 2014

By Robert F. Chaiken

An absorption-desorption model of particle reactivity was employed to describe the observed relationship between two apparently diverse phenomena which have been the subject of considerable study at the U.S. Bureau of Mines: (1) coal-rock dust reflectance and (2) coal-rock dust explosibility. The model accounts for heterogeneities in particle-size and material properties; however, in the present report, only particle-size distribution is considered. A mean particle-size parameter, appropriate to the explosion extinction process, is derived, and then taken as appropriate to describing optical reflectance. The derived form-to-function relationships for the two processes, when compared with experimental data, suggest that a problem exists with previously derived theory relating optical reflectance to rock dust concentration. A reexamination of that theory leads to a new theoretical expression, changed by a factor of 2, for the variation of rock dust concentration with reflectance which is in quite good agreement with experimental results. The current work offers justification for measuring and establishing rock dust requirements for specific coal dust size distribution(s) found in the mine-distributions that undoubtedly depend on the mining method and the type of coalbed.

Jan 1, 2010

By L. H. Johnson

"INTRODUCTION The Pennsylvania anthracite industry produced 53 million net tons of anthracite during 1945. Fifty-one million tons was prepared for the commercial market (3), 3/ and 2 million tons (consisting of fine sizes) was used for colliery power consumption. Of the number of tons prepared for market, 17 million tons (33 1/3 percent) was prepared by the use of acid mine water treated with lime.Mine water from underground workings is pumped, drained, and stored in huge quantities. The mine-drainage systems in the anthracite region handle over 200 billion gallons of water annually, of which 150 billion gallons is pumped to the surface. More than 69 billion gallons of water is impounded in underground pools (1). Much of this water is employed for breaker use, dust-control installations; hydraulic backfilling, combatting mine fires; and aiding in the transportation of anthracite in gently dipping places where sheet iron is used Roos(4) estimates that 1,100 gallons of mine water is utilized in the preparation of anthracite mined."

Nov 1, 1946

By D. A. Temple, G. O. John

Until recently, the approach to the problem of treating complex ores bas been to produce, insofar as is possible, mono-metal concentrates which are treated in traditional zinc, lead and copper smelting circuits, with the residues and by-products from some of these circuits being retreated for the recovery of contained values either by a separate residue treatment process or along with the primary feed to the appropriate circuit. The continued development of the Imperial Smelting Process, with its ability to treat poly-metal concentrates, calls for a re-examination of the traditional approach to this problem, and this the paper attempts to do. A survey of recent progress in the technical development of the process is made and a summary of current operational performance is included.

Jan 1, 1971

By Charles Kingsley

THE PRESIDENT (DR. C. B. KINGSTON, member C.l.M.M.) expressed regret that neither of the authors of the paper was able to be present to submit the paper in person. In their absence, it would be introduced formally from the Chair. It was a clear, straightforward account of a fine piece of shaft sinking, cleverly conceived and boldly executed. He referred briefly to the distribution and nature of the Dome ore-bodies and stated that, for both the miner and the metallurgist, the mine had provided a wide range of problems of unusual interest. Discussion on the paper was then invited. MR. THOMAS PRYOR said the paper was most opportune, because the subject of internal shafts did not appear to be fully treated in current mining literature. Many members were not familiar with Canadian gold deposits and it would be of interest if the authors could give a brief description of the location of the ere deposits of the Dome mine. This information would doubtless explain why a new internal shaft was needed in a position which required such an exceptionally long cross-cut to connect it to the main hoisting shaft to surface. It would also add to the value of the paper if the authors would give some idea of the duty expected of the new shaft in terms of tons of rock hoisted and of trips engaged in the transport of men and materials, and it would be helpful if figures could be given of the total capital cost of the hoists and subsidiary excavations at the shaft top, and of the cost per foot for sinking and lining the shaft below the collar. Turning to details of the paper, one was favourably impressed by the care given to the provision of a good travelling way for men in the main cross-cut, as shown in Figure 1. It was by no means always that one could walk in comfort and safety in a working where there was a 20-in. ventilating pipe in the roof.

Jan 1, 1939

By G. J. Slavens

The Bureau of Mines has devised technology to recover cobalt, nickel, and byproduct copper from domestic lateritic material using an oxidative, ammoniacal ammonium sulfate leach. Nickel, cobalt, and copper were recovered by solvent extraction and electrowinning. To reduce the cost and complexity of cobalt recovery, an alternate method using lig-nite to extract Co3+ was investigated as reported herein. In the first 25 BV (bed volumes) of solution contacted with lignite, 97 wt pct of the Co3+ was extracted in & downflow column at pH 9.3. After 85 BV, the lignite was loaded to 1.5 wt pct Co3+ and further ex-traction was minimal. The lignite extracted cobaltic ammine complexes rather than cobalt ions and was nonselective as to other -metal cations and ammonium ions. Deleterious cations and 80 wt pct of the nonammine ammonium ions were removed prior to acid elution of the lignite. The removal of the ammines prior to elution to produce an ammonium-ion-freeCo3+ eluate was only partially successful. Thus Co3+ removal from ammoniacal solutions by lignite is technically difficult and economically unfeasible. It was also determined that reduction of Co3+ to Co2+ occurred during the extraction-elution process.

Jan 1, 1984

By HILAND BATCHELLER

COMMENT on the economic significance of the special alloy steels seems inevitably to reduce itself to an attempt to peer into the future of the industry in which we are interested. We are all familiar with the historical development of iron and with the almost complete replacement of iron by steel. Those who have been connected with the industry since its .early days have had the satisfaction of witnessing the greatest industrial development the world has seen. As the cartoonists of the muck-raking decade liked to picture steel as an ogre armed with a spiked club, his hands reeking with blood and with golden coins dripping from his pocket, fiercely seeking for more widows and orphans to devour, I choose to call on my imagination to create a gigantic but beneficent robot of such marvellous mechanical skill. that it quickly transforms millions of tons of otherwise worthless material into the infinite variety of useful products which are so largely responsible for our present civilization.

Jan 1, 1931

By Nikhil Dhawan, Amit Barnwal

The present study reports a processing route to recover metals from integrated circuits of discarded random access memory (RAM) units containing ~ 66% printed circuit boards and ~ 33% integrated circuits. The integrated circuits are manually separated, grounded, classified, and subjected to water fluidization for the effective separation of metals. The significant separation was achieved via water fluidization, and the underflow fraction was magnetically separated. The magnetic fraction was thermally exposed in a muffle furnace, and the process optimization was carried out using a Box-Behnken statistical design. The detailed characterization at subsequent steps significantly aids the understanding of metal-plastic separation and enrichment. A concentrate containing 97% metals (Fe-59%, Ni-9.5%, Cu-7.7%, Sn-13.4%, Pb-5.6%, Ag-1.6%) with 96 wt% recovery can be recovered from discarded IC units. The process pursued is simple, adaptable, and environment-friendly, and the product can be used in conventional smelters.

Jun 23, 2020

By H. M. Thorne

The Union of South Africa has been interested in oil shale for a long time, and deposits of oil shales, torbanites, and similar rocks have been found in many parts of the country. (Fig. 1.) Samples differ markedly in oil yield and in the characteristics of the oil. The strata vary in thickness, and most of the deposits that have been found are in unfavorable locations because of remoteness from markets or absence of transportation facilities. This report deals mainly with the torbanite deposit near Ermelo, Transvaal, in the Union of South Africa, and the operations of the South African Torbanite Mining and Refining Co., Ltd. (hereafter referred to as Satmar), in mining the torbanite, retorting it, and refining the crude oil.

Jan 1, 1954

A preliminary program dated April 25, 1974 was prepared for Development Engineering, Inc. (D.E.I.) on research and development, laboratory; field and other engineering studies for the disposal of retorted oil shale. This program was revised and published as a final document dated December 17, 1974. The document included a discussion on the peculiarity of retorted shale materials to be investigated and a discussion of the various laboratory and field tests which would need to be conducted to define their physical and chemical properties. The proposed research and development program was divided into eight work phases as follows: I - Program Development II - Exploratory Laboratory tests on old U.S.B.M., retored shale III - Laboratory tests on Pilot Plant retorted shale IV - Laboratory tests on retorted shale from Semi-Works Plant, and field and test plots and ponds. V - Field compaction tests

Jan 1, 1975

By W. R. Hardwick

This Information Circular describes the development of block-caving methods and practices by the Miami Copper Co. at the Miami mine in Gila County, Arizona. It is one of a series published by the Bureau of Mines on mining methods, practices, and costs in various mining districts of the United States. This report gives a history of the district and outlines early prospecting and exploration including methods of sampling and estimation of ore tonnage and value at the Miami mine. Early mining methods are described, particularly those that influenced developments in the caving method. Mine exploration, development, and operating methods for block caving are described with particular attention to those factors, physical, economic, engineering, and managerial that have improved efficiency in the mining operations over a long productive period. Extraction, ventilation, wage system, safety, water supply, power plant, and shop facilities are discussed. The last section gives a brief summary of such costs as are available for publication.

Jan 1, 1965