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By L. C. Atkinson, E. A. Azrag, T. M. Hanna

The results of using a simple analytical solution and a relatively complex numerical model to estimate ground water inflow to an open pit mine are compared. The analytical solution assumes lateral, radial flow to a fully penetrating pit in an idealized confined aquifer, whereas the numerical model simulates fully three-dimensional flow to a partially penetrating pit from a water table aquifer. The latter is a more realistic simulation of the problem, but the former method is significantly easier to use. Comparison of the results obtained with the two methods for some typical hydrogeologic conditions encountered in mining yields ratios between them in the range of 0.2 to 0.6. These values can be used as a coefficient in the Pit Flow analytical solution to produce reasonable estimates of in-flow even when there are significant differences from the idealized conditions implicit in its application.

Jan 1, 1995

By Michael D. Balen

The plate-glass windows in the bus were cracked and mud-coated. Nevertheless, they afforded an excellent view of the many head-on collisions we narrowly avoided along the route from the Magadan airport to town. Apparently the driver thought the left side of the road was smoother than the right side, for he drove in the wrong lane at all possible times, even in the face of oncoming traffic. As far as we could tell, neither side of the road was any better than the other. Either way, we had to hang on just to stay in our seats. We careened past trucks and pedestrians, nearly always in the face of impending disaster. When the bus finally pulled into the parking lot of the Okean Hotel in Magadan, we had to thank the driver, not only for safely delivering his passengers, but also for the lasting first impression he gave us of the Russian Far East.

Jan 1, 1995

By J. A. Brierley, C. L. Brierley

The history, current applications and future of biotechnical developments in the metals' extraction industry are reviewed. Bioleaching of copper minerals continues to be the most significant application. Uranium bioleaching was successfully demonstrated at industrial scale. Developments are now being made in biooxidative pretreatment of refractory gold concentrates, ores and low-grade materials. Advancements are forthcoming in water and solid mine waste bioreclamation, including metals' biosorption, wetland treatment of acid mine drainage, and biodegradation of cyanide in spent, heap-leach operations. Better understanding of the types and functions of microorganisms involved in metal interactions could advance genetic engineering applications in bioleaching and bioreclamation.

Jan 1, 1993

By J. J. Moore, I. Iwasaki, L. A. Lindeke

Correlation of scale-up from small-scale batch laboratory mills to large-diameter industrial mills was established by performing two series of laboratory and pilot plant grinding tests using a magnetic taconite ore and a siliceous sulfide ore. In one series, controlled batch grinding tests in 203-, 508-, and 914-mm (8-, 20-, and 36-in.) diameter mills were carried out followed by a second series involving continuous grinding tests using 305-mm (12-in.) and then 1067-mm (42-in.) diameter pilot plant ball mills in open circuits. The effects of ball diameter on wear and of mill diameter on grinding power and ball wear are illustrated.

Jan 1, 1988

By P. B. Marchant

Bioleach testing and piloting was conducted on refractory gold sulphide concentrate from Austin Gold Venture in Nevada during 1988. The objective of the test programme was to determine the technical and commercial viability of bioleaching as a concentrate pretreatment step prior to gold extraction by cyanidation as an alternative to shipping concentrate to the smelter. Baseline CIL cyanidation typically resulted in < 20% gold extraction from the Austin concentrate. Bioleaching enhanced gold extraction up to 95% using conventional CIL techniques. This paper summarizes the bioleach test programme and results, including pilot plant studies onsite, and describes aspects of the commercial design for a possible retrofit of the Austin flotation tailings leach circuit to accommodate 20 tpd and 40 tpd capacity concentrate bioleach facilities.

Jan 1, 1989

By M. Li, J. D. Miller

Recently water insoluble alcoholic solutions of alkyl hydroxamic acid collectors have been shown to be particularly effective in the flotation of coarse feed material sampled from phosphate operations in Florida, North Carolina and Utah (Miller et al., 2000). The experimental results indicate that high separation efficiencies can be achieved in single stage flotation with these new collectors. In some cases the concentrate grade reached 34% P2O5 with 93% recovery from single stage bench scale flotation experiments. Critical aspects of the composition and structure of these new collectors are discussed with respect to their effectiveness in phosphate flotation. The wetting characteristics at fluorapatite, francolite, dolomite and quartz surfaces are being investigated with the new collector. Finally, other surface chemistry considerations in the development of these new collectors for phosphate flotation are discussed.

Jan 1, 2002

The sixth annual conference of the Mineral Economics and Management Society (MEMS) was held Feb. 27 through March 1 in Boulder, CO. This year&apos;s event was attended by more than 100 academic, industrial, government and other professionals interested in mineral economics and materials management. With about 250 members worldwide, this not-for-profit society seeks to promote scientific and economic analysis of current relevant issues. This year&apos;s program was sponsored by Alcan, Bateman Engineering, Cyprus Amax Minerals, J.P Morgan, Knight Piesold LLC and Newmont Gold. The conference&apos;s technical program consisted of six sessions. These included "Financial tools for a changing world," "Access to minerals," "Comparing North and South America," "Environmental issues in today&apos;s world" and "Transporting minerals." The program was concluded with a panel discussion titled "National minerals policies in Asia." In addition, a student papers session was held, in which students were given the opportunity to compete for a $1,000 award. The following is a brief review of the technical pro¬gram.

Jan 1, 1997

By D. A. Gulley, L. J. MacDonnell, William A. Vogely

INTRODUCTION Environmental impacts are most commonly associated with air and water pollution. Not- withstanding this fact, to many people the primary disruption caused by mineral extraction is the change in the character of the locale. That is, the environmental impact of mining includes, but is not limited to, the generation of residuals. The dramatic transformation of wilderness or rural land often creates strong reactions to mineral development. Thus, the basic issues of land use management are a useful addition to environmental discussion. In this section, we take up a discussion of federal, state, and local land use management regimes, along with a brief introduction to the potential role of economic analysis. Elsewhere in this volume, land management issues are discussed from other orientations, and the interested reader may wish to look there as well. Locatable Minerals on Federal Lands Legislation and Administration: Access to hard-rock minerals on the public lands is governed by the General Mining Law of 1872. This law declares that "valuable mineral deposits in land belonging to the United States . . . are hereby declared to be free and open to exploration and purchase . . . ." In order to initiate rights, prospectors are required to physically stake claims of specified sizes and shapes following basic procedures set by federal law which may be supplemented by the individual states. Rights to these claims are protected at the exploration stage so long as actual possession is maintained and diligent exploration activity is underway. If a valuable mineral deposit is discovered on the claim, the claimholder earns the exclusive right of possession as against private parties so long as the claim is properly maintained. To maintain this exclusive right the claimholder must per- form $100 worth of labor or improvements, known as assessment work, on each claim every year and make related annual filings with the U. S. Department of the Interior. If the existence of a valuable mineral deposit can be demonstrated, and other legal requirements are met, the claimholder may receive a patent giving full title to the claimed land, including the surface in most cases. The purchase price is either $2.50 or $5 .OO per acre. The Mining Law has remained largely un- changed by legislative amendment during its now more than 100-vear existence. However, while the law itself has not changed, its interpretation and administration have changed considerably. Written at a time of rapid western expansion of the U.S. following the Civil War, the intent of the law was to promote mineral development by inviting unrestricted prospecting and by selling the lands containing mineral deposits at a minimal charge. As federal land policy shifted from one of rapid disposal into private ownership to one of retention and management for a number of uses, mineral patenting requirements have been administered more strictly. The most critical issue concerns what must be demonstrated to establish the existence of a valuable mineral deposit. The so-called "prudent man" standard was established in the case of Castle v. Womble (19 L.D. 455 (1894)):

Jan 1, 1985

By J. M. Baker

It seems appropriate here to open with a quotation from the great pre-Confucian philosopher Lao-tze: "The softest thing in the world dashes against and overcomes the hardest. There is nothing in the world softer or weaker than water, and yet for attacking things that are firm and strong there is nothing that can take precedence of it." I am happy to report that our system of mining has worked out, with minor modifications, as well or better than was predicted. This, in a period of rising labor and material costs, has been most gratifying. Gilsonite is a solid hydrocarbon which occurs in vertical fissures cutting the sandstone and shale beds of the Uintah formation in south¬eastern Utah. It is found in other parts of the world under similar occurrence but nowhere else is it now being mined commercially. The Gilsonite veins on entering the shale members of the Green¬river formation break into small veinlets separated by shale, These veinlets are not now economical to mine.

Jan 1, 1959

By W. M. Shaver, W. R. Dengler

INTRODUCTION In Canada, most of the rock being broken in underground metal mines is being carried out using traditional drilling and blasting methods. Despite advances being made in hard rock boring and other, more exotic techniques, it is Dynatec&apos;s belief that the traditional methods will continue to prevail for many years to come. It is also our belief that modest research efforts expended on the traditional methods will result in substantial financial benefits to the mining and rock tunnelling businesses. Dynatec has pursued productivity improvements through the use of long rounds in both shaft sinking and lateral development. The concept of longer rounds was developed by Dynatec on the Craig Shaft Sinking Project (RETC 1991). This paper reviews the Craig Shaft Long Round success. This technology was subsequently utilized to sink the two shafts at Aur Resources with great success. The development of a Long Round Jumbo for tunnelling is a natural progression of the long round technology developed for the Craig Shaft. RECENT HISTORY OF SHAFT SINKING Shaft sinking is one of the oldest and most difficult mining methods. Due to the relatively small amount of shaft sinking in proportion to tunnelling and

Jan 1, 1993

By J. Derwin King, Harrison R. Cooper

Applications of nuclear magnetic resonance (NMR) offer possibilities for on-line sensing of the concentrations of several elements in flowing sample streams. In addition to hydrogen, these elements, generally of low-order atomic number, include aluminum, phosphorus, fluorine, sodium, boron, and lithium contained in minerals having commercial importance. Many such elements have been difficult or impossible to successfully measure on-line using the more familiar X-ray fluorescence and neutron activation analysis techniques. The availability of practical on-stream analysis methods is essential to applying advanced controls to processes incorporating these elements. On-stream NMR instrumentation has been demonstrated in the past for several process applications including, as an example, coal flow and analysis; and the technology has recently been extended to the measurement of phosphorous BPL in Florida beneficiation plants. The technique involves simultaneous sensing of proton (hydrogen) and 31P intensities to provide data for continuous calculation of BPL in the phosphate through calibration to volume fractions of water and solids. Initial operating results are described using the PhospholyzerTM on-stream phosphorous analyzer designed for plant application.

Jan 1, 1990

By J. P. Barbosa, R. V. V. Araújo, R. B. E. Trindade

Bromide stabilizes the auric or aurous ion by forming a stable complex in acidic aqueous solution. The oxidizing agent normally used for the process is bromine, which is a corrosive liquid with high vapour pressure. This is, in fact, the main reason why it has not found acceptance yet as an industrial oxidant for gold. Ferric ion with hydrogen peroxide and/or sodium hypochlorite have already proved to be effective oxidants for the dissolution of gold from a rotating disc in a bromide-containing aqueous solution. In the present work, preliminary tests with four selected ore samples were tested to evaluate the dissolution of gold with the same system already tested with the rotating disc (Br-/Fe3+/H2o2/NaCIO). Compared to the conventional cyanidation, results were superior in one instance only. The major obstacle seems to be the maintenance of a suitable potential to allow the complex formation. However, the studied system may be interesting, is in some situations it may yield better results than conventional cyanidation; therefore, further investigation seems to be worth doing.

Jan 1, 1995

By N. Dahotre, C. Blue, C. Zhao, B. Parekh, D. Tao, G. Engleman, R. Honaker

Equipment wear is one of the major concerns in screening of coal and minerals. Not only does it decrease the screen service life, it also results in inconsistent aperture sizes and deteriorates the efficiencies of downstream operations. In this research, a coating technique based on laser surface engineering (LSE) was successfully developed to increase the life span of raw coal screens. The microstructure and wear properties of the coating were investigated in this study. Enhanced wear resistance performance (up to 11-fold increase) of coated screens has been achieved in laboratory wear tests.

Jan 1, 2006

By A. T. Weber, G. T. Adel

Earlier studies on the hydrodynamic interactions between fine particles and air bubbles have shown that fine particle flotation can be improved by using small air bubbles. In the present work, microbubbles ranging in size from 70 to 250 microns have been used in a flotation column for the processing of fine coal. The performance of the microbubble column has been studied as a function of wash water addition rate, aeration rate, feed rate and column length to diameter (L/D) ratio. The information collected from these tests has been used to analyze column behavior and to develop scale-up criteria. The results of this investigation suggest that mixing within the column may not be as significant as bubble size and residence time in determining column performance. Improved recovery can be obtained by decreasing bubble size which increases the flotation rate constant, and also by increasing L/D which increases residence time for a fixed column volume. The increase in residence time with L/D is due to a decrease in the volumetric flow rate of wash water with column diameter.

Jan 1, 1988

By C. R. Stephan

Explosion-resistant seals in underground coal mines isolate the environment within the sealed area from the active workings of the mine. The current United States Title 30 Code of Federal Regulations (CFR) requires these seals to be constructed of solid concrete blocks. The CFR also allows for alternative methods or materials to be used to create a seal if they can withstand a static horizontal pressure of 138 kpa (20 psi), provided the method of installation and the material used is approved in the ventilation plan. The purpose of this report is to identify those explosion-resistant seals that have been tested and meet or exceed all the requirements of the CFR.

Jan 1, 1997

By H. E. Goetzman

A cooperative research project supported by the taconite industry and the Minnesota DNR was undertaken to establish quality standards for carboxymethyl cellulose (CMC) based organic binders. The objective of this study was to identify the effect of CMC quality parameters such as degree of substitution, molecular weight, and purity as well as the effect of inorganic extenders such as sodium carbonate on performance. These factors have been evaluated by green-ball testing with two taconite concentrates followed by pot-grate tests. Balling tests with bentonite and Peridur were conducted to provide baseline data. At a constant DS the molecular weight as measured by viscosity had the greatest effect on green-ball drop strength. Dry-ball compression strength was most dependent on CMC addition rate and sodium carbonate content. DS was not found to have a major effect on green-ball quality for medium molecular weight CMC.

Jan 1, 1988

By C. Ceccarini, I. Salvadori, G. Oggiano

GENERAL BACKGROUND The first mention of the presence of bauxite in the mesozoic series of north-west Sardinia (fig. 1) is owed to Oosterbaan, a Dutch geologist, who carried out a geological survey of the area in the ninetten thirties. A more detailed study of the mesozoic series was attempted in the fifties by Pecorini and other, who concentrated particularly upon the stratigraphy of the bauxitic horizons, through examination of the various outcrops. In the sixties a pining company, Monte Amiata S.p.A., turned its attention to a section of the deposit outcropping near Olmedo and, considering it to be of some promise, carried out prospecting works consisting essentially of various trenches, some bore holes, a few adit and a. layout plan for the preparation and execution of trial exploitation. The results, although positive, did not convince the company&apos;s shareholders to continue the exploration. This report, which is intended as a new contribution to knowledge of the Sardinian bauxite deposit, takes into account the information acquired not only from a drilling prospection begun in 1979 in connection with the SOMIT-PROGEMISA joint venture, but also the results of structural studies and numerous chemical, mineralogical and

Jan 1, 1984

By J. C. Yingling, R. J. Sweigard, S. T. Mickleborough

The geostatistical technique of conditional simulation is applied to measure the uncertainty inherent in the factor-of-safety (FS) predictions for soil slopes in which there is an incomplete knowledge of the spatial distribution of soil properties. A case study that considers a natural clay slope in Canada is presented. The sequential-indicator simulation technique was used as a means of generating a series of spatial maps of the soil properties at the site. These maps approximate random draws from the conditional probability density function that characterizes existing uncertainty in the spatial distribution. FS determinations were made for each simulated map using the simplified-Janbu approach. In using this approach, computations are performed using a new computer program that can operate on irregular spatial profiles of soil properties specified on a discrete grid. A unique capability of this approach is the ability to generate the FS distribution conditional to the type, position and value of existing site-characterization measurements. This capability should reduce uncertainty in FS predictions.

Jan 1, 1996

By A. Shtiza

This literature review discusses the role of the Albanian institutions, the natural resources industry, potential investors and stakeholders in order to provide a set of indicators that can help to monitor amelioration within sustainable development principles. A map with the potential prospects of the natural resources will be a first step in identifying the further potential for exploitation. Mineral resource policies and governance, sustainable processing and supply chain as well as environmental management information system are some of the crucial tools identified, that will help to set up the indicators and quantify the achievements in environmental management in Albania. Moreover, the integration of practices that will support institutional capacity building; follow-up practices; the mainstreaming of global environment into planning; and the compliance monitoring process will additionally improve the environmental situation in Albania. Aligning business strategy with environmental policy, socio-economic analysis, environmental auditing are decisive tools in order to provide the Albanian authorities with a clear overview of the economic costs and the social benefits for sustainable development.

Jan 1, 2011

By John B. Rigg

Thank you Mr. Chairman. It was a generous introduction. It allays some of the puzzlement I have of being a minority among the speakers at this conference. I see from the program that only two of us have been asked to speak on topics in keeping with an election year. Instead of reporting facts on past events as most speakers are, J. W. Wilson, of Consolidation Coal, and I have been designated to forecast the future. Forecasting in an election year implies a liberty to fabricate at will, hallucinate, fantasize, stretch fact and fancy and generally prognosticate without regard for the consequences. Since I&apos;m not seeking your votes, promises aren&apos;t mandatory. This will be done with supreme confidence stemming from profound wisdom and a foolproof crystal ball. So instead of soliciting your vote, I&apos;ll simply penetrate 24 years of tomorrows, which may not be much different than some of us remembering the later hours of last night. My remarks do not draw upon Gulf planning department projections. Instead they are a roll of the dice of personal conjecture to stretch your imaginations on oil shale mining through the year 2000. In this regard, it is sobering to keep in mind that it has been in my lifetime that investors wouldn&apos;t risk a dollar on paperback books, motels, supermarkets, or drive-in restaurants. And only thirty years ago it was predicted by an eminent Ivy League professor

Jan 1, 1976