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By J. W. Hawkins, K. B. C. Brady, K. Miller, J. Cuddeback

Remining of abandoned coal mines in Pennsylvania requires the implementation of pollution abatement and mining techniques called Best Management Practices (BMPs). Water-quality data from over 100 remining sites with more than 230 abandoned discharges were analyzed with respect to the types of BMPs employed to abate the pollution loadings of acidity, iron, manganese, aluminum and sulfate. Discharges exhibiting a significant decrease in acidity were most highly associated with sites where large volumes of alkaline materials were encountered (66.7%) or added (63.7%). The best results for iron loading were achieved with large-quantity alkaline addition (54.6%) and water handling systems (47.8%). Water handling systems (47.4%), daylighting (40.7%), and revegetation (40.2%) were associated with significantly lower manganese loadings. The decreases in acidity and sulfate loads associated with increasing the amount of alkaline material in the backfill indicates that the production of acid mine drainage can be retarded by adding large quantities of alkaline materials.

Jan 1, 2002

By David Shatwell

Recent epithermal gold discoveries in Chile and Bolivia provide increasing evidence of a belt of intermittent, epithermal, precious metal mineralization east of the main Andean porphyry copper belt. This relationship may be the result of an easterly decrease in the age of magmatism and erosional levels, in¬crease in depth above the underlying Benioff zone and consequent changes in magma chemistry, or some other unrecognized factor. Examples are: • The Choquelimpie gold-silver mine in Chile and numerous other epithermal prospects (such as La Riviera, Bolivia) in late Tertiary volcanics along the Chile-Bolivia border. These lie east of the belt that contains the Toquepala, Quellaveco and Cuajone porphyries in southern Peru and the Cerro Colorado, Copaquire and Quebrada Blanca porphyries in northern rhila

Jan 1, 1990

By M. N. Chandraprabha

This paper discusses the role of mineral-adapted acidiphilic microorganism Acidithiobacillus ferrooxidans on the beneficiation of arsenopyrite containing multisulfides (pyrite and chalcopyrite). Adaptation to minerals altered the surface properties of the microorganism. Bacterial adaptation to arsenopyrite and controlled bacterial adhesion to mineral surfaces lead to selectivity in arsenopyrite separation. Bioremoval of arsenic ions (both arsenite and arsenate ions) by Acidithiobacillus ferrooxidans is also discussed.

Jan 1, 2009

By C. F. Barter, H. G. Kreis, D. S. Weber

Before and during in situ mining at the Santa Cruz In Situ Copper Mining Research Project test site, hydraulic testing was conducted at injection and recovery test wells to characterize patterns of fluid movement in the 5-spot well field. Testing included borehole spinner flow meter surveys, single-well and multiple-well injection and recovery tests, straddle packer injection tests, and bromide pulse tracer tests. Results of hydraulic testing for determination of fluid flow regimes were used to modify well and mining zone hydraulics for the purpose of increasing fluid migration in flow pathways of the mining zone with higher copper grade.

Jan 1, 2000

By E. H. Cho, B. Conner

Three sulfide minerals, chalcopyrite, sphalerite, and pyrite, were leached using a bioleaching mode and an electrobioleaching mode. The former mode was used to leach the minerals with the bacterium A. ferrooxidans in a bioreactor. In the latter mode, the leaching of the minerals was performed in a combination of a bioreactor and an electrochemical cell. In this set-up, the solution was circulated between the bioreactor and the cathode compartment, the two reactors were in series, and the cell was operated intermittently. The mechanism is such that an increase in Fe(II) concentration, which is a nutrient of the bacteria, by electrochemical reduction of Fe(III) would increase the bacterial population and in turn would accelerate the leaching of the mineral. It has been found that the electrobioleaching of chalcopyrite is an improvement over the bioleaching with respect to the fact that leaching conversion is higher and a high level of Fe(II) concentration can be maintained. However, the electrobioleaching of sphalerite does not show any improvement over bioleaching. The electrobioleaching of pyrite is similar to that of chalcopyrite, and this has potential to be used in applications such as coal desulfurization and pretreatment of refractory gold ore in heap leaching where fine gold particles are entrapped inside pyrite particles.

Jan 1, 2006

In 1988, at the request of members of the Society for Mining, Metallurgy, and Exploration (SME) Inc., the president of SME formed Working Party No. 79, Ore Reserve Definition. Its mission was to develop guidelines for the public reporting of exploration information, resources and reserves. These guidelines were published in the April 1991 issue of Mining Engineering (pp. 379-384), and as a document entitled “A Guide for Reporting Exploration Information, Resources, and Reserves” in January 1992. Work continued on an ad-hoc basis until 1996. Working Party No. 79 was then renamed the SME Committee on Resources and Reserves and became a standing committee.

Jan 1, 1999

By E. V. Manlapig

This review paper describes recent advances that have been made at the Julius Kruttschnitt Mineral Research Centre (JKMRC) in Brisbane in developing a framework for simulating the flotation process. The work has been carried out collaboratively with the Mineral Processing Research Unit of the University of Cape Town in South Africa (UCT), as part of the Australian Minerals Industries Research Association (AMIRA) P9 Project. The framework consists of four components, namely – the mathematical model of the flotation process, suitable measurement tools for characterising the flotation cell, a computer program for modelling and simulating the process and the plantas for testing and validating the flotation models. A brief description of the model is first presented, then a number of applications of the model are described. The paper shows how the model can be used to optimise the performance of flotation cells, and then two case studies on the modelling methodologies are described. Finally the current and future plans of the project are outlined.

Jan 1, 2001

By T. Mudder, R. Cellan, R. Waterland, J. Whitlock, B. N. Nelson

The effectiveness of anaerobic in-situ biological treatment for the immobilization of selenium, molybdenum, and uranium in an alluvial aquifer was examined using long-term column tests. A series of organic substrate and nutrient combinations were tested to determine removal effectiveness, optimum supplement concentrations and ratios. Final column testing was conducted to determine the chemical stability of the treatment by-products/treatment compounds by dosing the columns continuously with elevated redox untreated alluvial groundwater.

Jan 1, 2002

By G. Wozniak, R. Rostanski, H. Pfanz, G. Aschan, E. Sierka

"Industrial wasteland is a typical element of the landscape of all the industrialised regions in Europe. There are many examples from Poland as well as from other European countries that post-industrial sites have been undergone natural colonisation and succession to establish in some cases ecosystems of greater biological diversity than the original ecosystems. The post-industry sites regardless of any reclamation carried out, undergo natural successional processes. The respective biological diversity (number of species, and number of plant assemblages) reflects the micro-variety of the specific habitat. This paper summarizes the results of investigations, which have been carried out since 1989 on coal mine water sedimentation pools in the Upper Silesia Industry Region. The aim of this study is to demonstrate the diversity of spontaneous plant communities recorded on post-industrial waste sites. In the course of the long time fieldwork, plant assemblages representing nine phytosociological groups have been identified."

Jan 1, 2005

By Z. Zhang, R. G. Reddy

Viscosities of industrial lead slags with various compositions were measured as a function of temperature using a Brookfield viscometer. Based on the experimental data from this study and other investigations reported in the literature, an expression has been developed to correlate the viscosities of lead silicate slags as functions of composition and temperature. The effect of each individual slag component on the variation of the slag viscosity is identified. The composition dependency of viscosity of lead silicate slags is discussed. The calculated results using this viscosity expression are in good agreement with the measured data.

Jan 1, 2001

By L. B. McConville

The general term "tar sand" has been used to describe sand containing varying amounts of dense, viscous petroleum. Deposits of tar sands have been found throughout the world, often in the same geographical area as conventional petroleum. The largest one by far is known as the Athabasca Tar Sands, and is located in the province of Alberta, Canada. Actually a group of three deposits, these particular sands underlie an aggregate area of more than 12,000 square miles. Current estimates place the contained raw petroleum at about 700 billion barrels, from which as much as 300 billion barrels of synthetic oil may be recoverable under presently developed technology. For comparison, this latter quantity is roughly equivalent to five times the combined total of U.S. and Canadian crude oil reserves. With the ever-widening gap between energy supply and demand, attention is being directed to all possible energy sources - both developed and underdeveloped - and certainly the Athabasca Tar Sand deposit is one of the more important ones to merit such attention. This paper will review some of the more significant developments and attempt to place in perspective the role that this source of energy could possibly be expected to play in the foreseeable future.

Jan 1, 1974

By W. Z. Rogers

U.S. feldspar output sold or used in 2005 was an estimated 760 kt (838,000 st), valued at $44 million free-on-board plant. This was below the 2004 volume and was the second year of decline in a row. Output included flotation concentrates, feldspar content in feldspar-silica mixtures, potash feldspar and aplite. The strong housing market in the United States maintained demand for ceramic tiles, plumbing fixtures and fiberglass insulation requiring feldspar. Shipments of glass containers were about the same as in 2004. Imports of ceramic tiles and plumbing fixtures continued to increase, taking the place of U.S.-produced goods and the feldspar required to make them. For 2005, 80 percent of the ceramic tiles sold and 50 percent of the plumbing fixtures sold in the United States were imported. Since 2000, manufacturing plant closures in the plumbing fixtures industry have reduced the demand for feldspar and feldspar-silica mixtures by 100 kt (110,000 st). Increased demand from the ceramic tile industry has partially offset the lost volume.

Jan 1, 2006

By G. Brackebusch, S. J. Jung

Backfilling techniques are widely used in large-scale underground mines. Massive pillars, which have been left in place for stability, limit mining activity. Backfilling allows safe recovery of the ore remaining in pillars and assures long term stability. In deep mines expected high stress can be relieved with the backfill. Initially, waste rock was used to fill the openings with mixed results. The need to improve safety and reduce costs has prompted the industry to investigate alternatives. Hydraulic filling with Portland cement added has shown considerable promise, but little has been done to define the parameters of design effective system. The purpose of this study is to determine the relationship between backfill and mining components that can be used to effectively design a best-case hydraulic backfill.

Jan 1, 2000

By E. Tulcanaza

M.S. Azun I do not at all agree with the basic points of the author's conclusion. The use of lognormal or normal model to respond to the attribute distribution function should be carefully questioned. If fitting a distribution function of regionalized variables is the main purpose, one may employ one of certain well-known families of distributions, such as Tukey's lambda functions. For instance, the distribution function of gold assay values studied by Krige (Krige, 1978) may fit the lognormal model well, but one should not exclude that the basic idea of using the distribution function of observed data is to have insight of the physical mechanism that gives rise to the regionalized variables. In Applied Geostatistics, there are many examples considering only lognormal or normal model for the distribution function of geostatistical data even if the observed distribution function has more than one mode. Of course, using lognormal or normal model always brings easy computation for the statistical properties of attribute under investigation. Still, I object to adopting any of those models without having any "statistical inference." As seen from the author's paper, lognormal and normal model produce the same average grade (0.746% copper) and almost the same sample variance. Therefore, which model explains the probabilistic behavior of ore deposit is always an important question that should be replied by the geostatistician using not the common sense but the statistical and probabilistic methods. For kriging procedures, such as linear kriging, one should describe either second order stationary properties or bivariate properties of regionalized variables. Second order properties, such as correlogram function or semivariogram function, are the inputs of the so-called kriging equations. Selecting one of any useable models for the observed second order properties, such as spherical model, is not easy since the models are not based on the correlations structure of the regionalized variables. How those models being used in Applied Geostatistics can be distinguished is another important problem. One may develop many fitting models to respond to the observed second order properties of regionalized variables. However, I suggest that the model should be based on the probabilistic behavior of geologic process. The author used spherical model for copper, wolfram, and silver grades from isotropic sector (Fig. 2, 4, 3b) and exponential model for silver grades obtained along raises in isotropic sector (Fig. 3a). It seems that those semivariograms given in Fig. 3b for isotropic sector and Fig. 4 may be described by the random model implying that regionalized variables do belong to renewal process (Azun, 1983). If I knew the total number of data points used in estimation, I may prove that my conclusion is correct. Recalling the test for the first order sample correlogram value, the test procedure is introduced such that the independence is rejected if [ ] where Za/2 is the a/2 percentile of standard normal random variable and N is the total number of samples used in estimation (Azun, 1983). For the other observed semivariogram functions I suggest the author might try to use the so-called "Markovian model" describing not only the correlation structure of regionalized variables, but also the physical mechanism that produces the regionalized variables. The Markovian model for correlogram function is, [ ] The Markovian model for the other second order properties of ReV are also derived. T ve B, in the above equation, show, for example, structural change and mineralizational variation in a considered deposit, respectively (Azun, 1983). In selecting any model, it is not easy to search for the "best" response to the observed second order properties of ReV's. The Markovian model, based on a theoretical understanding of underlying mechanism, gives more information about the occurrence of regionalized variables and respond to all properties. Random model and the so-called hole effect structure can be easily defined as a special form of the Markovian model (Azun, 1983). An estimation of any second order properties of regionalized variables may be computed through (N-1) lag. However, the dependency between the regionalized variables may be deemed to have "died out" after the so-called stationarity width (range). In practice, the estimation is carried out through 25% of the total number samples available. Therefore, the large fluctuations around the zero level and variance for correlogram or covariogram function and semi-variogram function, respectively, cannot be observed. Since the number of pairs involved in the estimation of higher second order properties is small, the estimation variance at those lags is large. There is no need to show higher order estimated second order properties. After using one of any kriging procedure for block estimation, the distribution function of average grades has the same mean as the drilling sample grades but

Jan 3, 1985

By Edward D. Graf

Once the heavy work of mining, supporting and completing an underground structure is finished, there is frequently the problem of handling unwanted water infiltration into the opening. Methods of controlling the infiltration vary from collecting and channelling the inflow to shutting off the water at the surface of the opening or within the ground formation. Discussed are various methods of controlling ground water inflow from within the structure including collector pipe systems, shotcrete, cement grout, bentonite, and various chemical grouts. Case histories illustrating some of the methods and materials will be presented.

Jan 1, 1987

By D. R. Dolinar

The fall of small pieces of rock between roof bolts causes over 80 pct of the ground fall injuries in underground coal mines. Roof screen, if installed on the bolting cycle, can significantly reduce the number of these injuries. As the surface of the roof fails, the screen will have to retain the broken rock without failing or excessive deformation. Welded wire screen is the most common type of screen material used for roof surface control in underground coal mines. The load-deformation characteristics and the load capacity of welded wire screen were evaluated in the laboratory in a specially built test frame. In the frame, the square screen sections were held in place by bolts and bearing plates at the four corners while a center load was applied to the screen. The parameters evaluated included the wire gauge and configuration, the bearing plate loads and bolt spacing. The wire gauge of the tested screen was 4, 6, 8, 9 and 10. Maximum screen capacities for both load and displacement were developed for each of the wire gauge sizes along with the screen stiffness. This information can be used for screen selection and for the evaluation and determination of screen performance. DISCLAIMER: The findings and conclusions in this report have not been formally disseminated by the National Institute for Occupational Safety and Health and should not be construed to represent any agency determination or policy.

Jan 1, 2009

By Thomas S. Nye

Mineral exploration in the United States relies heavily on theoretical geologic concepts and indirect methods such as geophysics and geochemical prospecting, as there are few exposed areas of mineralization which have not already been explored at least once. In Mexico ore-grade samples can be cut at the surface on vein, replacement, and disseminated types of deposits in many areas. Here the problem is not in finding a mineralized area but in deciding which mineralized area can be explored and developed at the least risk and cost, and have the greatest profit potential, within the framework of Mexican mineral economics and government policies. Mexico's min¬eral industry is regulated through a system of permits for various phases of mineral exploitation, and by taxes. This regulation and its effects are not unlike those which may be expected in the United States if present legislative and administrative trends continue.

Jan 1, 1972

By Jr. Raleigh

As part vi the development of the Coal Quality Expert (CQRN) --a computer program capable of predicting the impacts of coal quality on power plant performance, costs, and emissions control--several nationally important coals are being characterized to augment the coal quality database associated with the software. The project is sponsored by the U.S. Department of Energy and the Electric Power Research Institute (EPRI) under the Clean coal Technology Program. Since 1989, CQ Inc. (a subsidiary of EPRI) has characterized seven bituminous coals from Alabama, Illinois, Kentucky and Oklahoma and six sub-bituminous coals from the Powder River Basin (PRB) in Montana and Wyoming. Coals from the PRB region--being burned more frequently in Midwestern and southern power plants to reduce emissions of sulfur oxide compounds--can sometimes contain significant concentrations of potentially toxic elements. Although no limits were imposed on air toxics emissions from fossil-fuel fired utilities by the Clean Air Act Amendments of 1990, future regulations may be implemented at the conclusion of Federally-mandated emissions studies. One possible result is that any increased utilization of coals, including those from the PRB, may depend on the potential for removing toxic trace elements prior to combustion.

Jan 1, 1993

By L. Tercero Espinoza, F. Marscheider-Weidemann, C. Gandenberger

"A reliable supply of non-energy raw materials is a precondition for the functioning of the European economy. In line with its importance, the issue of raw materials supply has become more prominent in the past years, especially owing to turbulent raw material markets. However, these turbulences are not due to depletion of the geological resources but to a missmatch of (expected) supply and (expected) demand, with several interacting factors influencing the markets both from the supply as well as from the demand side. A recent evaluation, published in June 2010 within the framework of the EU Raw Materials Initiative, sought to bring together these two sides of raw material markets and asked the question "which raw materials are critical for the EU?" Herein we present the methodology used by the Ad-hoc Working Group on Defining Critical Raw Materials and the results obtained, complemented by results from the study "Raw Materials for Emerging Technologies"."

Jan 1, 2011

By James W. Clark

This paper is a description of certain geologic aspects of the Inspiration mining operation. It is not a geologic description of the Inspiration deposit nor an exposition of all the geologic work involved in the development and exploitation of the deposit. A few specific examples of the application of geology and geostatistics to the mining process are given to illustrate the progress that has been made in making the Inspiration Mine more efficient and cost effective, and a statement of the philosophy of geologic applications is offered.

Jan 1, 1984