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By M. K. McCarter

The history of mining education, like the history of the mining industry, is typified by “boom and bust” cycles. In academia, the perpetual problem can be stated as “too many graduates for the jobs or too many jobs for the graduates.” The deep “bust cycle” that spanned the 1990s through 2003 spawned renewed efforts to eliminate, consolidate, restructure, rename, reinvent or otherwise change mining education to make it (for some) more fiscally or socially acceptable. During this period, a number of mining programs were eliminated, and by the late 1990s senior people in academia and their counter-parts in industry became increasing concerned about the very real possibility that strategic disciplines may disappear altogether. As a result, the Mining and Metallurgy Society of America (MMSA) created an educational committee to explore how industry could help preserve key programs necessary to provide future professionals. Several meetings were held to assess the problems and look for solutions. In 2004, this effort culminated in the first of the “Engineering Education” sessions to be held at the SME Annual Meetings. In response to the information presented in this first meeting, Marc LeVier (then president of MMSA) invited a number of the participants to reconvene the following day. An action plan was formulated and a task force was organized. To more fully represent all industry sectors, SME later that year assumed the sponsorship role for the task force.

Jan 1, 2007

By Verônica Scarpini Candido

Foi notado que o rejeito originado a partir do beneficiamento do caulim é rico em silico-aluminatos, apresentando assim potencial em processo de adsorção. O presente trabalho consiste em avaliar o potencial adsortivo do rejeito do caulim quimicamente tratado. Foi utilizado o corante de azul de metileno (AM) em solução aquosa para se ter o conhecimento de adsorção do rejeito de caulim in natura e calcinado a 700ºC onde ambos foram submetidos a uma ativação química com H2SO4. Após o equilíbrio da amostra do rejeito do caulim junto ao azul de metileno, suas concentrações foram determinadas por espectrofotometria. Os resultados preliminares comprovam que o rejeito apresenta uma boa capacidade adsortiva para concentração de até 50,00 mg/L de AM, demostrando, potencial para ser utilizado na remoção de corantes em tratamento de afluentes.

Oct 30, 2017

By C. Konya, A. Konya

"INTRODUCTION Over the past twenty years this Linear-Regression Modeling has become widely accepted for ensuring limits are not exceeded at a site, using the Scaled-Distance variable. In today’s industry, numerous equations are present for different scenarios, geologic environments, hole sizes, and numerous other factors with an emphasis on site-specific equations developed for all major projects; however, underground blasting applications have not been analyzed to a great degree of detail. Without previous knowledge this puts underground blasting operations into a guessing-game to ensure that vibration levels are not exceeded. This paper will review two recent projects that have been worked on by the authors and linear-regression models that were used with both burn cuts and stope blasts. BLAST VIBRATIONS MODELING The first major research project conducted in the United States on blasting vibration was Bulletin 442 (Thoenen & Windes, 1942) which looked at the relationship between blasting and blast vibrations in the fall of 1940. This study examined numerous blasts and began the investigation into topics such as damping, structural damage from vibrations, frequency dependency on vibration, resonance vibration, delayed blasting, and numerous other factors. Bulletin 442 had two major conclusions which are: 1. The vibration from a blast can be predicted with a relationship of size of the shot and distance to the structure (now known as scaled distance) 2. “The vibration of a structure at resonance does not in itself cause damage because of the restraining effect of damping inherent in the building” (Thoenen & Windes, 1942) Due to the increase of blasting near homes and busier areas the USBM commissioned an additional study to further develop a few of the topics covered in Bulletin 442; this study would go on to be published as RI 6561 (Duvall, Johnson, Meyer, & Devine, 1963) with the study looking into delayed blasting and the relationship between charge weight, distance, and peak particle velocity of the blast. This relationship would be termed as the ‘scaled-distance’ and take the form of:"

Jan 1, 2018

By Martin Irving

Adding Value to Canadian Diamonds - A Changing Diamond Industry - Diamond Mining - Diamond Manufacturing - Diamond Jewellery Markets - NWT Diamonds Changing Diamond Industry - De Beers ? privatization - Oppenheimers (45%), Anglo-American (45%), Botswana (10%) ? going retail - LVMH joint venture - New Players ? jurisdictions - Canada ? companies - BHP-Billiton - Aber Diamonds

May 1, 2002

By George A. Morgan

Output of mineral products was estimated to be unchanged in 1983 from that of 1982 with the exception of petroleum. The country began production of crude oil from the Seme Oilfield, and all output was exported. Wd and charcoal constituted 72% of Benin's total energy consumption, and imported petroleum products and electric power accounted for the remainder. Cement was produced from imported clinker. The gross domestic product (GDP) was $1,061 million in 1982, the latest year for which information was available.2 COMMODITY REVIEW Gold.-Exploration was underway at Perma by the U.S.S.R. as part of the United Nations development program. Gold had been produced previously at Perma, where a grade of 0.289 troy ounce of gold per ton was reported, An exploitation program for the deposit was to employ about 100 people, and output was targeted to reach 1,600 troy ounces per year. Recoverable reserves were put at 96,000 troy ounces.

Jan 1, 1985

By Elmer R. Kaiser

G. A. Vissac (Consulting Engineer, Vancouver, B. C.) —Some of the data presented in this paper, in connection with cost studies of washed coals, should be clarified and qualified. Washing a raw coal down to a low ash content may mean higher losses in refuse, but the cost of the operation may be more than compensated by the increased value of the resultant product. However, careful engineering and accurate machinery are required to insure maximum profits. Washing at a low gravity separation demands a very accurate automatic process, chiefly when the small sizes of coal are being handled. Coal consumers today are buying mostly on a Btu basis, cognizant of the fact that low ash contents result in lower installation costs and in savings in handling and transportation charges. The attached Table X gives the actual balance sheets of the various cleaning operations corresponding to various ash contents for the two coals presented in the paper, using the old technique of a two-products separation. or the new technique, now commonly used in Europe, of a three-way separation made possible by new methods and new equipment. Savings in capital costs, handling, and transportation have been calculated on the basis of a delivered cost f.O.b. plant of $10.00 per ton of coal at 16.5 pct ash (actual 1953 average price reported by Consolidated Edison, N. Y.), and of $3.50 at the mine also for 16.5 pct ash coal. In both cases this corresponds to values of 126 and 4.26 per 1 pct of combustible and per ton, respectively, on delivered and on at the mine prices. As an example, the middle western coal at 16.5 pct ash, raw, washed down to 4 pct ash in a two-way process will give 53.75 pct of clean coal at 4 pct ash and 46.25 pct of refuse at 31 pct ash. The value of the losses will be 0.4625x(100—31)x0.042 = $1.34. Add the cost of washing, capital, and operation, which is $0.35. The total cost will then be $1.69. But with a three-ways separation we will have 53.75 pct of first-grade coal at 4 pct ash, 37.25 pct second-

Jan 1, 1955

The conclusions reached by den Tex after a study of the fabric of some rocks from Broken Hill have been used to support the epigenetic hypothesis for the origin of the ore, first by Edwards (1959, p. 70) and then by Stillwell (1962, p. 131) in his criticism of Segnit's (1961) views. Den Tex claimed that the petrofabric study provided "independent evidence that the ore, at least in its present form, post-dates all events of a diastrophic nature in the area concerned".Repetition of this claim by Edwards and by Stillwell and the lack of any criticism of den Tex's work for more than three years implies its general acceptance by geologists in Australia. Therefore it appears necessary to examine parts of den Tex's paper in detail to show that his, conclusions are unwarranted. The major weaknesses in his study are that1. the petrofabric study was inadequate to warrant any major conclusions, and2. the petrofabric data allow alternative conclusions.Den Tex made a single visit to the field, collected six carefully selected specimens and presented quartz and· biotitepetrofabric diagrams for two specimens, quartz-diagrams alone for three more and included three diagrams of the orientation of c-axes and fractures in one specimen. It is not reasonable to come to firm conclusions about the origin of such a complex area as Broken Hill on such inadequate data, despite den Tex's claim (p. 87, lines 22 and 23) that "a thorough investigation of the quartz-fabric of the wall rock was undertaken".Den Tex's interpretation of each diagram is open to criticism, and alternative (and to my mind, preferable) interpretations may be made. It is impossible to evaluate den...

Jan 1, 1962

By H M. Ahmed, W S. Dunbar

Construction of cave mining systems requires significant capital expenditure and long-term commitment of human, equipment and material resources before production commences. Risks and uncertainties of these large-scale mining projects are significantly higher than for small-scale projects. This is due to the complexity and interactions of the construction schedule components and the large scale and uniqueness of such projects. One way to successfully manage construction uncertainties that would lead to schedule delays is to include a reasonable cost contingency in the budget estimation. A real options approach based on the least-squares Monte Carlo (LSM) method is used to estimate cost contingency associated with schedule uncertainty in mass mining projects. Cost contingency is estimated as the cost of potential project crashing (acceleration) decisions, which pays for not extending the schedule. While such a significant undertaking is expected to be subject to some delays, these can have an enormous impact on the economic value of such projects. The value of the crashing option was explicitly formalised into the process of valuation, as it is assumed to be a single option being considered in the valuation at every decision point prior to the construction completion date. As a part of the proposed method, a stochastic function for the percentage of remaining scope of work for the remaining duration of the entire project was integrated into a framework of numerical simulations. This ensured that this function can implicitly account for sources of schedule uncertainties for projects represented by multiple and overlapping work packages. The LSM method was applied to a real case scenario in an operating block cave mine, with modified scale and features. The results yielded by the LSM method indicated that significant changes in capital budget allocation stem from variation in a contractor’s risk perception and confidence level of estimated delays.CITATION:Ahmed, H M and Dunbar, W S, 2016. Budget estimation and contingency allocation of block cave construction using least-squares Monte Carlo real options, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 801–808 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By D. François-Bongarçon

When it comes to sampling theory, a bad sampler is a bad sampler, no matter what, and a sampler is either bad or good. It also is of critical economic importance to tell and understand the difference, especially in a metallurgical plant. In this paper, the grand principles of Sampling Theory are first recalled, then the most popular types of sample cutters for plants are critically reviewed. It is concluded that the industry has a lot of progresses to make in that direction, although improvements usually pay for themselves very quickly.

Jan 1, 2002

The negative effects of pyrite and pyrrhotite on thiosulfate gold leaching have been investigated. Possible remedies to reduce some problems are discussed. In a gold bearing pure silicate ore, 92% of gold could be extracted within 3 hours using a solution containing 0.2 mol/L ammonium thiosulfate, 0.9 mol/L ammonia, 30 - 300 ppm copper sulfate and 8.6 ppm dissolved oxygen at pH 10.26. The thiosulfate consumption was 7.1 kg/t under these conditions and could be further reduced to 3.5 kg/t by decreasing the dissolved oxygen to 0.3 ppm. Addition of 16% pyrrhotite or pyrite into the silicate slurry led to a decrease in gold extraction by 2% or 9% respectively and an increase of thiosulfate consumption by 11 kg/t or12.8 kg/t respectively in three hours. Several adjustments, such as increasing copper ion and ammonia concentration and reducing the dissolved oxygen level to 0.3 ppm resulted in increased gold extraction and lower thiosulfate consumption despite the presence of these sulfides.

Jan 1, 2005

By C. J. Farrow, M. J. Smith

"Bechtel has managed a number of test programs to establish autogenous grinding circuits and size mills for a variety of ores.This paper outlines the procedures whereby bench scale and pilot plant tests are used to select the most efficient circuit to grind the range of ore types likely in the mill feed.Five examples are given. One example traces the development of a pilot plant program; it shows how bench scale Work Indices provide a target for the grinding power requirement of an ore and relates how pilot circuits are changed as a result of interpreting the results from preceding tests. The other four examples relate the interpretation of the test results to provide design data; they illustrate a number of phenomena which have been observed.INTRODUCTIONConventional crushing and grinding circuits can be specified from bench scale test data such as Bond Work Indices. Bond Indices have been correlated to a large number of rod and ball mills and by applying appropriate factors, mills can be sized from the Work Index.For autogenous or semi-autogenous grinding circuits, bench scale tests are not sufficient to be able to specify the circuit and size of the mills for a commercial plant. It is necessary to run a series of pilot plant tests to determine how the ore behaves."

Jan 1, 1982

By S A. Campbell

There has been a reduction of coal production in the United States due to environmental pressure and the increased use of natural gas. This reduction will require coal producers and consumers to make decisions on whether to sample more to verify contract quality or sample less in an effort to cut costs.CITATION:Campbell, S A, 2014. The shrinking coal market in the US – sample more or sample less?, in Proceedings Sampling 2014 , pp 3–6 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

By Robert Hopler

After the disbanding of the Gunpowder Trust Association in 1904, the Association of Independent Powder and Dynamite Manufacturers was formed, followed in May of 1906 by the formation of the Association of Manufacturers of Powder and High Explosives. Due to a lack of success in attracting all manufacturers to membership, these organizations did not survive.

Jan 1, 2014

By Axel Preusse

For the last 150 years, subsidence damage to the surface has been an unavoidable phenomenon associated with underground coal mining. In particular, the mechanization of mining methods in multiple seam mining and the concentration of mining activities in densely populated European metropolitan areas (e.g., Ruhr, Upper Silesian industrial region) have led to mining having a very strong influence on the earth?s surface. In both these regions, surface subsidence of more than 20m has been reported up to now in comparison to the original state. Underground coal mining in these regions strongly impairs all kinds of surface use, such as urban and industrial development, infrastructure (roads, waterways, and railways) and pipelines?without restricting the functionality of those objects to a greater extent. Demanding and, in some cases, globally unique engineering solutions have been developed and implemented for this purpose. The previously mentioned mining and industrial regions are still very strongly characterized by the (increasingly declining) coal industry and will remain dependent to a large extent and for an indefinite period on artificial drainage measures because subsidence that has already occurred is irreversible. This paper will primarily discuss the prediction of subsidence that is caused by intensive multiple seam mining and its influence on surface objects (e.g., underground pipelines). However, an approach for predicting ground uplifts due to rising mine water as a consequence of mine closures will also be described.

Jan 1, 2012

By L. A. Stewart

This paper describes all occurrences of barite in Arizona that were known or reported to the authors. The history, ownership, production, and geologic setting are discussed for most of the deposits. The uses and specifications of product grades are briefly discussed. Seventy-five deposits were examined in 9 of the 14 counties of the State. The descriptions are given under county headings. No occurrences were reported in the four northeastern counties of Coconino, Navajo, Apache, and Greenlee, nor in Santa Cruz in the southern part of the State. From about half of the deposits examined, 55 samples were taken; of these, 45 were for chemical analysis, and 8 larger samples, ranging from 100 to 350 pounds, for beneficiation tests. A 30-ton bulk sample was taken for pilot-plant tests. Bench-scale flotation tests of the eight samples employing several different procedures and reagent combinations yielded marketable-grade barite products with barite recoveries ranging from 60 to 97 percent. Five of the samples contained enough fluorspar to warrant its recovery. Acid-grade concentrates, which accounted for fluorspar recoveries of 45 to 70 percent, were obtained from three of these ores. Batch laboratory tests of a representative portion of the 30-ton bulk sample revealed that acid-grade fluorspar and high-grade barite concentrates could be recovered. Results of the laboratory and continuous pilot-plant tests of this ore will be presented in a separate report.

Jan 1, 1960

By S. E. Phillipson

Underground mine mapping is a critical component of understanding the controls on ground instability. Many relatively localized examples of ground failure are associated with geologic features, such as faults, joints, compaction zones, or sedimentological transition zones. In contrast, long-running, directional roof falls are associated with regionally directed horizontal stress fields, which are induced by tectonic plate interactions in the earth?s crust. When stress-related features are distinguished from geological features, underground mapping can be an effective method for inferring the direction of horizontal stress at individual mines. Comparisons with data compiled in the World Stress Map confirm that underground mapping can be a valid method for determining the orientation of maximum principal horizontal stress at a variety of scales, ranging from individual mines to an entire mining district or coal basin. Comparisons are presented between the maximum horizontal stress directions inferred by MSHA?s Roof Control Division through underground mapping and the azimuths of maximum horizontal stress in the World Stress Map database for North America?s Pennsylvanian-aged Appalachian, Illinois, Black Warrior, and Arkoma Basin coal fields. The comparison indicates that azimuths are similar for both data sets, even where variations in the direction of horizontal stress are present. It is interpreted that inconsistencies in direction are attributable to near-surface affects such as deeply incised stream valleys, or to fault zones that represent heterogeneities in the crust.

Jan 1, 2009

By Edward Steidle

NOTHING stands still. We go forward or backward. As a distinct group of educators, our immediate concern is with the preparation of young men and women for participation in the mineral industries on a professional basis. I am going to have the temerity to state emphatically that for a long time as a whole we have remained in a static position. We are now confronted with the choice of advancement or retrogression. We are still in a position to make a choice and our ultimate fate will depend upon the course of action we elect to follow. Wars always have been great catalysts and social and scientific advancements mature under military stimulus in a fraction of the time normally consumed. We are now in the midst of a conflict whose duration or final effects cannot be estimated. However, the record already demonstrates that this war as never before is a mineral war in which incentive, strategy, and outcome are directly related to the distribution and utilization of minerals. The inevitable result is a drain upon our resources now reflected in our record production and a growing public consciousness of the importance of minerals in the role of human affairs. It is evident that we must seek new mineral frontiers beyond the borders of the United States and take every other precaution to forestall a "have-not" position in the world.

Jan 1, 1943

The compliance sampling method for coal mine dust in the United States has not changed appreciably in the last 30 years. A call for more frequent sampling with immediately available results is leading to new instruments that may supplement or replace the existing sampler. This report discusses two such instruments that provide immediate results of dust levels. The first, called the Respirable Dust Dosimeter (RDD), is designed to supplement the existing U. S. cyclone compliance sampling method. It uses the pressure drop across a filter to provide an inexpensive screening type of measurement. The RDD has been tested in the laboratory and a limited number of coal mines. Side by side testing has compared the RDD performance with personal coal mine samplers in triplicate area sample measurements. Results show that the differential pressure of specific filtration media can be an effective surrogate for respirable mass. Data show that there is a dependence on coal type and an effect of relative humidity. There also appear to be two distinct responses related to coal type. For specific coals the coefficients of determination, R2, are better than 0.9. For general use the detector tube, using laboratory generated calibration curves, can be used to estimate respirable dust levels. However, a calibration to a specific coal type may substantially improve the accuracy. Another sampler in development is called the Personal Dust Monitor (PDM). Designed to give compliance quality accuracy, the PDM uses the frequency change of a vibrating element to measure dust and give immediate feedback of results. Results of laboratory comparison of the prototype PDM sampler to personal gravimetric samplers indicate R2 values of better than 0.99 for three different coal types. Work is in progress to package the components into a person-wearable unit combined with a cap lamp system with a total projected weight of less than 1.4 kg (3 lbs).

By R. S. Dean

In addition to the normal work and that pertaining to strategic minerals, the Metallurgical Division has been made responsible for carrying on major investigations in the development of processes' for the treatment of low-grade domestic manganese ores that heretofore have failed to yield products suitable for the preparation of ferromanganese, an alloy essential to every ton of steel produced. These investigations are particularly important at this time because of their part in tucking this country self-sufficient with regard to manganese when the stock-piled ore becomes e exhausted and as foreign shipments of ferro-grade ore are cut off. The results indicate that there is a good probability of accomplishing this objective, while at the same time conservation may be promoted through the use of normally useless material from the large, low-grade ore deposits.

Jan 1, 1941

By Nathaniel Arbiter

Flotation’s earliest patent was issued in 1860. However, the process was first applied commercially in Australia until 1904, and in Montana in 1911. Major advances followed both in reagent treatment and in cell design, with resulting process improvements. Mechanical cells have seen the widest use and with the major increases in plant capacities (Fig. 1) their volumes have also increased (Fig. 2). In 1991, the principal use for the process was to produce copper concentrates for smelting. It was applied to 243 Mt (268 million st) of copper ore. The total of all ores floated that year was 426 Mt (470million st). In 1997, US mines produced 257 Mt (284 million st) of copper ores for flotation, yielding1.75 Mt (1.94 million st) of copper.

Jan 1, 2000