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By Michael A. Trevits

The National Institute for Occupational Safety and Health (NIOSH) in partnership with Strata Products tested the sealing capability of Ventstop®? as part of an ongoing mine fire control and suppression research program. Ventstop®? is a multi-purpose, inflatable device that is produced by Minvent Solutions and is available world wide for use in the metal and nonmetal mining industry. Ventstop®? is also used in the Australian coal industry as a temporary ventilation control device. The device can be quickly deployed, is reusable and can be placed in horizontal and vertical mine voids to control dust, fumes and smoke. Deployment, multi-day inflation and air leakage tests were conducted at the NIOSH Lake Lynn Laboratory to determine the capability and limitations of Ventstop®? in a simulated coal mine setting. During the tests, Ventstop®? was also subjected to low level forces of a nearby methane gas ignition. It is thought that Ventstop®? could be used by the US coal mining industry to temporarily close an underground mine area in response to a fire or spontaneous combustion heating event, to temporarily redirect mine ventilation during longwall equipment moves or during stopping construction. This paper describes this inflatable temporary mine sealing technology and presents the results of the NIOSH tests.

Jan 1, 2009

The capability for on-line measurement of the quality characteristics of conveyed coal now enables mine operators to take advantage of the inherent heterogeneity of those streams and split them into wash and no-wash stocks. Relative to processing the entire stream, this reduces the amount of coal that must be washed at the mine and thereby reduces processing costs, recovery losses, and refuse generation levels. In this paper, new approaches for optimal control of the segregation process, using time series models and empirical distributions, are presented and demonstrated using field data.

Jan 1, 1998

By Sam H. Patterson

Fuller's earth and bentonite are two clay commodities that are interrelated either by mineral composition or use. Because of this interrelation and the sale of both for many different uses, some ambiguity in their classification has resulted. The term "fuller's earth" has no compositional or mineralogical meaning, and it is used more or less as a catchall for any clay or earthy material suitable for certain uses. Most, but not all, of these uses require absorbent properties. Bentonite by geologic definition must have formed from volcanic ash or tuff or the glassy material in volcanic rock; most bentonites consist chiefly of montmorillonite but other clay minerals may be present. In industrial usage the term "bentonite" is applied to any clay consisting chiefly of montmorillonite, irrespective of origin. Georgia and Florida have historically been the leading States in the production of fuller's earth; bentonite has been produced in Alabama on a small scale. The first major use of fuller's earth was in refining of oils. Other materials have replaced fuller's earth for this purpose to a major extent, but many new uses for fuller's earth have been found, and production has increased in recent years. The new uses include absorbent products, insecticide and pesticide carriers, drilling mud, and many others. The bentonite now produced in Alabama is of the "southern," "low selling," or "calcium" type and is used mainly as foundry-sand bond. Most of the fuller's earth mined now is in the Hawthorn Formation of Miocene age; a lesser amount is produced from the Twiggs Clay Member and other beds in the Barnwell Formation of Eocene age. Inactive pits from which fuller's-earth was produced from other formations occur at several localities. The bentonite now mined in Alabama is in beds of Cretaceous age; several years ago bentonite was produced from Eocene beds in this State.

Jan 1, 1972

By N. J. Ferguson

An upsurge in demand for Australian coal has seen a much needed programme for a new generation of coal ports. This paper discusses design concepts in planning a large modern terminal, with the 25 Nt/a Port Kembla and the 50 Mt/a Newcastle facilities as practical examples. The need is emphasised for a studied Master Plan, in-built materials handling flexibility and staged development. Trends in bulk ship design and loading methods are noted. Features of these Australian designs include methods of dealing with poor ground conditions, functional civil engineering for environmental protection and optimal marine structure designs.

Jan 1, 1982

By C. W. Armbrust

At FHC Gold Company's Paradise Peak Mine gold and silver are produced. Precious metals recovery rates are very satisfactory along with the recovery and production of a relative high volume of mercury. At Paradise Peak precious metals are recovered via the Merrill-Crowe process and delivered to the refinery area as a mercury-bearing precipitate cake. The recovery of mercury is then obtained through a vacuum retort system. The balance of the material is mixed with fluxes and then melted and cast into dore' bars for shipping. Issues of retort capacity and concerns over efficiency led to research into the retort process itself.

Jan 1, 1990

By Albert F. Duzy

Recently there have been some problems associated with hot coal in shipments from the USA to overseas markets. This paper will serve several functions. First, a brief review is presented, together with a selective bibliography. Second, a thorough discussion of coal oxidation is covered. Third, potential effects of storage are presented and, lastly, methods are suggested for the safe storage and bulk transfer of coal. The scope includes coal storage for power plants.

Jan 1, 1983

By G. F. Joklik

Although the mineral shortages of twelve to eighteen months ago have given way to oversupply, their memory lingers on. These problems were man-made: booming demand throughout the industrial world, political and industrial unrest and the oil embargo all contributed. But in the minds of many, the shortages conjured up visions of the depletion of the world's mineral resources, a disaster that could be staved off only by drastic curbs on consumption and therefore, curbs on economic growth. A little historical research shows that fears such as this are not inventions of the 1970's. A hundred years ago, for example, the imminent exhaustion of the world's coal supplies was being predicted in Great Britain. The English economist, John Stuart Mill, who was usually more perceptive, wrote a few years earlier that "it is only in the backward countries of the world that increased production is still an important object". And later there was Franklin Roosevelt who said in 1932, "Our industrial plant is built; the problem just now is whether under existing conditions, it is not overbuilt". His concern, in other words, was not with the discovery and exploitation of new natural resources, but with the administration of known resources and with seeking foreign markets for surplus production. In light of copper prices at the time -- just under 6¢ a pound -- that was understandable. These instances illustrate how, throughout the world's industrial history, concern about surpluses of raw materials has alternated with alarm about the adequacy of supplies and with calls for restricting growth.

Jan 1, 1975

By J. Richard Lucas

Today, the future of the coal industry is extremely bright because coal can be produced at a cost which makes it competitive with other energy sources. However, the industry has been forewarned that further cost reductions must be made if it expects to remain a serious contender in the growing energy market. Surface as well as underground operations must be improved. The very same elements which affected production a. few years ago still exist today and will continue to be present in the future. Improvement's in production mining equipment, mining methods, and auxiliary equipment have resulted in reduced costs over the past few years. Efforts must be continued toward further reducing costs in areas which have been improved previously, and new areas should be investigated for possible improvements. Therefore, new techniques must be developed which will enable the industry to augment its current efforts in reducing the cost of mining. The logical place to begin evaluating the factors affecting production and cost is in the immediate face area where a substantial part of the total cost of mining is incurred. The coal industry stands to gain much through the development of new techniques for analyzing the numerous variables affecting production and by establishing methods for eliminating or minimizing the adverse effect of those variables which can be controlled. Intuition and trial-and-error methods have been the standard means used to resolve many of the factors which influence production. As a result, many elements are overlooked or ignored because their effect on production is not pronounced and cannot be readily resolved. The need for a method of analyzing such factors was recognized by the Office of Coal Research. Therefore, in April 1962, under OCR sponsorship, a. research project was initiated at Virginia Polytechnic Institute (VPI). The objective of the project was to identify the factors which influence mining costs in the immediate production area, and to develop methods and techniques which will enable the coal operator to minimize production costs. The objective of the research at VPI has been successful, and techniques have been developed for establishing quantitative facts concerning the interrelationships of production activities.

Jan 1, 1965

By Fredy A. Elorrieta Agramonte, Gabriel von Rickenbach, Roberto Luis Fonseca, David Córdova Rojas, Rolando Romero, Rico Brändle

The mine’s economic life is dynamic by nature. Some factors that create this scenario are the need to recognize new exploitation areas, the evolution of the mineral prices and the development of new technologies to access them. The dynamics of mining development, especially in the underground environment, changes significantly as the stages unfold. In many cases the final solution differs greatly with the initial. The frequent presence of new conditions and factors often cause the mine to develop in a quasi-permanent transition stage, which could be characterized by the generation of dynamic micro-seismic events that could cause rockburst damage in some specific areas. Although they may be infrequent, these dynamic events can have an important adverse impact on mine safety and causes serious losses. Also, changes in the production schedule during exploitation could be a big issue if the problem is not effectively addressed. When the transition of the mine to an active micro-seismic environment begins as an unforeseen scenario, it is frequent to use static ground support systems as they are readily available. Traditionally, the support systems used are reinforced shotcrete with a middle layer of Welded Standard Wire Mesh (WSWM) and Chain Link Standard Wire Mesh (CSWM) of reduced gauges, i.e. wires less or equal than 4 mm in diameter. Although, this support system is used to control static instability problems, there is no good reference of its energy absorption capacity under dynamic load conditions, creating uncertainty in the effectiveness of controlling rockburst events. These support systems are analyzed at the present paper, testing the reinforced shotcrete layer with 4 mm diameter of WSWM and CSWN under dynamic load. Additionally, the influence of the use of high tensile strength steel wire in the meshes (HSWM) compared to the previous ones, is analyzed to assess the scope in controlling rockburst events and keeping the safety of underground environment.

Apr 26, 2022

By R. K. Agarwal

In this paper a simple three-layered medium is considered. A circular hole is centrally located in the intermediate layer. The layered sheet is loaded uniaxially perpendicular to the stratification. The Young's modulus of the intermediate layer is lower than that of the outer layers. The stress distribution around the circular hole in a stratified medium is significantly different when compared to the case of a continuous homogeneous medium. The distribution depends upon the ratio of the height of [the] intermediate layer and [the] hole diameter. A comparison of stress the distribution and procedures for preparation and testing of [the] model are given. The potential of the technique is outlined.

Jan 1, 1968

By P. J. Best

Due to its low mine production costs, competitive rail rates and low sulfur content, the Southern Powder River Basin (SPRB) now commands 30 percent of the U.S. utility coal market. In 1996, production exceeded 260 million tons, a growth of 110 million tons since 1989 and 15 million tons over 1995. Continued growth is expected as the second phase of the Clean Air Act Amendments (CAAA) looms. This growth will be the greatest in the southern part of the basin, where coal quality is higher. This article is an overview of supply and demand issues affecting markets for SPRB coal. It reviews the current markets for SPRB coal and addresses future prospects for market expansion.

Jan 1, 1998

By Mark Colwell

This paper summarizes the results of a research project whose goal was to provide the Australian coal industry with a longwall installation roadway (faceroad) design methodology that could be utilized by suitably qualified colliery personnel. This goal was achieved in 2012 and the design methodology (and software package) is referred to as Analysis and Design of Faceroad Roof Support (ADFRS). The intended benefits to underground operations, in the provision of this information and resource, are a safer and more productive workplace.

By Thomas S. Mackey

The industrial types, sources, and quantities of USA tin residues are identified and the methods of treatment reviewed. The effect of a lower tin price, due to a current major world surplus of tin metal, is mentioned and covered in some detail. The names and locations of over 100 USA firms recovering tin residues are listed. Current smelting and refining charges are included to convert the residues into tin metal and alloy. The impact of the suspension of the LME daily tin price since October 24, 1985 to date, and the failure of the International Tin Council to support the Buffer Stock Manager are reported with comments.

Jan 1, 1986

By Geoffrey G. Hunkin

This is a brief state of the art paper describing current (1975) Uranium recovery plant flowsheets, some notes on system selection, design philosophies, and materials of construction. The in-situ, or borehole solution mining, of Uranium is a process which has been developed over recent years to better match Uranium mining and milling technology with the size, shape, grade and territorial distribution of the remaining identified Uranium deposits of western United States. Solution mining recovery plants are pure hydrometallurgical units ideally suited to automation, modular design, and mobility. Similar to conventional Uranium mills, two basic flowsheets, one acid and one carbonate, are in use, but the predominance is reversed so that the majority of plants employ the alkaline carbonate flowsheet, All plants incorporate resin bead ion exchange Uranium recovery for both acid and alkaline circuits.

Jan 1, 1976

By F. L. Pirkle, W. C. Bagby

"In his 1989 book, The New Realities, Peter F. Drucker, Clark Professor of Social Science at Claremont Graduate School, Claremont, CA, stated: “Information is data endowed with relevance and purpose. Converting data into information thus requires knowledge. And knowledge, by definition, is specialized” (p. 209).The discipline of mineral valuation is knowledge-based and requires a mineral valuer to collect, analyze and interpret data that are material to a mineral-valuation assignment. In so doing, the valuer turns the data into information (data come first, followed by information as determined by the mineral valuer) for use by the client (from whom the valuer obtained the mineral-valuation assignment) and other intended users. The valuer uses his or her experience and education (each valuer’s knowledge base) supported by a foundation built upon competency, materiality and transparency, the three pillars of mineral valuation (minerals valuation, mineral-property valuation).The International Mineral Valuation Standards Template (IMVAL Template), third edition dated May 2018, defines mineral valuation as: “The estimation of the value of a mineral property in money or monetary equivalent. The word ‘valuation’ can be used to refer to the estimated value (the valuation conclusion) or to refer to the preparation of the estimated value (the act of valuing)” (p. 14).Furthermore, the IMVAL Template clearly separates valuation from evaluation: “The template deals with valuation, which is distinct from evaluation. The distinction inherent in these defined terms is that valuation addresses the estimation of value of a mineral property, whereas evaluation addresses the broader assessment of a mineral property for an investment decision (p. 2).”This is an important difference because the minerals industry commonly makes investment decisions using feasibility studies to evaluate a proposed mineral development and production project. The purpose of such investment-decision analysis is distinctly different from valuation of a mineral property, no matter where that property lies upon the mineral explorationdevelopment- production-reclamation timeline (Fig. 1). Valuation involves terms such as market value, just compensation, fair value, etc., whereas investment-decision analysis is concerned with the economic viability of a given proposed project. Although feasibility analysis and market valuation can both use discounted cash flow (DCF) analysis as a tool, the formulation of the DCFs and their interpretation are different."

Nov 1, 2019

By L. A. Rapoport

This paper outlines the methodology and results pertaining to the simulation of the U.S. coal industry in the context of an integrated, time-dynamic model of Long-Range Energy Developments and Supplies (LORENDAS). By way of background we will present first an overview of the overall LORENDAS model structure. We will, then, outline the characteristics of the formulation and data used for the representation of the U.S. coal industry. Finally, a series of model results will be reviewed, with particular emphasis on the long term projections of coal production and distribution under different basic economic and/or political scenarios.

Jan 1, 1977

By M. W. Smith

Pennsylvania has 2500 miles of streams that do not meet water quality standards due to acid mine discharge (AMD), making AMD the greatest cause of water pollution in the state. The problem is mainly caused by abandoned coal mines. Pennsylvania is using a watershed-based approach to abating AMD which includes remining as a key component of a comprehensive restoration strategy. The Tangascootack Creek Watershed was targeted for AMD restoration through remining. Geologic mapping and overburden data were analyzed using Earth Vision software to identify areas of coal reserves which could be remined to improve water quality. Incentives are offered to encourage mining in these designated areas.

Jan 1, 1999

By J. Sharp, R. Arnold, P. Rusin, T. Young, N. A. Sinclair

Many oxide silver and molybdenum deposits remain undeveloped because chemical extraction yields poor recoveries or is environmentally unacceptable. Bioreductive leaching of such ore samples at MBX resulted in high extractions of silver and molybdenum. When baseline, three-day, cyanide bottle-roll tests were conducted on manganiferous-oxide silver ore, 13.7% of the silver was extracted. In contrast, 86% of the silver was microbially solubilized into the organic growth medium by bioreduction with 99.8% dissolution of manganese. A followup cyanide bottle-roll test yielded an additional 8.5 % silver dissolution, for a total extraction of 94.5%. Baseline, three-day, acid bottle-roll tests of the iron-oxide molybdenum ore Yielded 1.8% molybdenum. However, bioreduction solubilized 93.3% of the molybdenum into the growth medium. An additional 0.3% molybdenum was solubilized during the followup acid bottle-roll test. Microbial treatment of refractory oxide ores with bioreductive bacteria resulted in higher extractions of silver and molybdenum than conventional chemical leaching. The bioleaching process occurred at a near-neutral pH at ambient temperatures. The bacterial solubilization of silver and molybdenum was achieved without the use of cyanide or sulfuric acid.

Jan 1, 1993

By John Stroiazzo, Bernard C. Aubé

Brenda Mines, located 22 km Northwest of Peachland in British Columbia, Canada was an open pit copper- molybdenum mine which closed in 1990 after 20 years of operation. The primary concern in Brenda's tailings and waste rock drainage is molybdenum at a concentration of approximately 3 mg/L. The mine drainage is alkaline and contains little or none of the typically problematic heavy metals. Given that the waters downstream are used for municipal water supply and some irrigation, a discharge limit of 0.25 ma molybdenum was imposed with specific water quality guidelines in the receiving creek. A review of all existing and potential molybdenum removal methods was undertaken prior to mine closure. The chosen process is a two-step iron co-precipitation with clarification and sand filration at a slightly acidic pH. A 4,000 usgpm (912 m3/h) treatment plant was constructed and commissioned in 1998, at a cost of $10.5M. The successful removal of molybdenum from the drainage water is explained with details on some design innovations and operational challenges encountered during plant start-up. Investigated sludge disposal options are discussed although the long term disposal scenario has not yet been finalised.

Jan 1, 2000

By Y. Guan

The adsorption of zinc species onto silica in ammonical solutions has been studied. Adsorption isotherms reveal that increasing adsorption occurs as the solution pH is made more alkaline. Fr-IR spectroscopy revealed that the adsorbed species is a zinc ammine complex.

Jan 1, 1993