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Jan 1, 1985

By William J. Wiehagen

The training of mining personnel is a large and continuing activity for the mineral industries. Although safety and skills training has long been recognized as an essential element for reducing injuries and improving productivity, the research literature lacks definitive reports documenting the specific value of such training. The training literature presents a variety of testimonials as to the "benefits of training," but lacks data that specifically tie that training to the performance of the worker.

Jan 1, 1983

By J. J. Renton

The iron disulphide minerals, pyrite and to a lesser extent marcasite, are ubiquitous to coal and coal associated rocks and are the source of nearly all the environmental problems associated with the mining, processing and utilization of coal. The iron disulphides as well as the other minerals in coal exhibit systematic spatial pat- terns of distribution on both regional and local scales and show predictable associations, most of which are determined by the geochemical-sedimentological controls under which they form. It is the purpose of this paper to discuss the geochemical-sedimentological conditions responsible for the formation of coal minerals with special emphasis on the formation of iron disulphides, to illustrate the regional and local patterns of mineral occurrence within coal, to present the microscopic associations of the iron disulphides and finally, to discuss the most important single environmental aspect of the iron disulphide content of coal and coal associated rocks; the production of acid mine drainage.

Jan 1, 1986

By H. H. Murray

Significant changes in ownership and production of industrial clays have occurred since 2000. Clays covered in this presentation are kaolins, ball clays, smectites, (bentonite), and palygorskite (attapulgite)-sepiolite. IMERYS discontinued production of paper coating kaolins at their Cornwall operations and have expanded their kaolin production in Brazil. J. M. Huber sold their kaolin operation in Georgia to KaMin whose headquarters are in Ft. Worth, Texas. BASF purchased Engelhard?s kaolin and attapulgite operations in Georgia. ActiveMinerals purchased Southeastern Kaolin in South Carolina, Wilkinson County Kaolin in Gordon, Georgia, and Zemex Attapulgite in Quincy, Florida. Chemical Lime purchased Spinks Ball Clay Company in Paris, Tennessee. Most of the ball clays used in Italy and Eastern Europe comes from expanded operations in the Ukraine. Bentonite operations have expanded production in Wyoming and Montana because of strong demand for drilling mud, foundries, cat litter, and iron ore pelletizing. The production and exports of palygorskite in China continues to increase. Nanoclays utilizing sodium montmorillonite, palygorskite, and halloysite are actively being developed.

Jan 1, 2009

By Donald E. Ranta

An ore zoning technique developed by Climax geologists during the past forty years has been used to contour drill-hole assay values on cross-sections for fourteen porphyry molybdenum deposits in western North America, including the Climax and Henderson orebodies. Detailed geological studies of these large, complex deposits are essential in determining ore controls, which are the factors most critical to the zoning of MoS2 assays and to conceptualizing geologic models. The technique provides a detailed representation of the size, shape, grade distribution, and geologic continuity of the individual deposits. It demands a disciplined approach and adheres to rigorous rules while maintaining flexibility for adaptation to widely varying geologic conditions. By defining the limits that guide and control manual, computer-assisted conventional, and geostatistical reserve estimates, it exerts a strong geologic influence on the estimation process. A combination of ore zoning and geostatistical analysis of molybdenum deposits produces a significantly more accurate, precise, and defendable geologic reserve estimate than other methods.

Jan 1, 1983

By Mingfei He, Jianhua Chen, Yingchao Liu, Yuqiong Li

Pyrite is one of the most common sulfide minerals on earth, which is usually grown with chalcopyrite and other sulfide minerals. In flotation practice, pyrite from different mines or different sections in a same mine may have different flotation behaviors. This is because the pyrite crystal contains lattice defect, including ionic vacancy and lattice impurity. The present work investigates the effects of three typical 3d transition metal (Co, Ni, and Fe) on the adsorption of CH3OCS2 −, OH−, and CN− on pyrite surface by density functional theory (DFT) calculations. Calculated results show that Co impurity reduces the adsorption energies of CH3OCS2 − and CN− on the surface of pyrite, while Ni and Cu impurities significantly increase the adsorption energies of CH3OCS2 − and CN− on the surface of pyrite. Co impurity has small influence on the adsorption of OH−, but Ni and Cu impurities significantly increase the adsorption energies. Calculations on Mulliken charge population of Co2+, Ni2+, and Cu2+ indicate that the Mulliken charges of Co2+, Ni2+, and Cu2+ after OH− adsorption are more than those after CN− adsorption. This suggests that the ionic property of the M-OH- coordination bond is greater than that of M-CN- coordination bond, while covalent bonding of M-CN- coordination bond is greater than that of M-OH- coordination bond. The adsorption results are discussed based on coordination field theory (CFT).

Oct 6, 2020

By Dieter Loh, Mathias Knoll, Florian Werres

When a new tunnelling project starts, it has been a vital tradition for decades to cast and erect master rings horizontally on a flat surface to demonstrate the compliance with dimensional tolerances. Some tenders ask for the erection of two or even three rings upon each other or repeated master ring erections at intervals throughout the project. Especially for large diameters, this is a challenging and risky task for the workforce in the segment factory. A truck-mounted crane is often necessary, and in some cases it can take up to a week to complete a master ring. The concept of virtual rings has the potential to replace this tradition by assembling master rings digitally instead of physically. This is based on a best-fit approach, considering the 3D coordinates from laser tracker measurements of segments or segment moulds. Building a virtual ring, a sub-millimeter accuracy can be achieved, the alignment of neighboring circumferential and ring joints observed, and the fit of bolt holes checked. The traditional method, on the other hand, is discussed controversially despite the significant amount of work and risks—particularly as the horizontal position of the ring and absence of gaskets do not simulate the reality in the excavated tunnel. This paper will highlight the technical aspects of virtual rings, as well as their pros and cons, illustrated by a case study from London Thames Tideway where a total of 30 physical master rings could be replaced by virtual rings.

Jun 13, 2023

By Gennaro G. Marino

This paper summarizes and evaluates data on mine subsidence ground movements and associated damage for houses in Illinois. Based on the data collected, the response of homes to subsidence ground movements is expressed in terms of repair costs. A damage criteria is then proposed that relates the ground movements and damage levels. The data were collected as part of a comprehen¬sive study performed for the Illinois Abandoned ?Lined Lands Reclamation Council, A -M-RC, by the Civil Engineering Department at the University of Illinois, and probably will be published in late 1934 by the council. The study concentrated its efforts on surface ground movements and the effects to houses over abandoned room and pillar mines. The resultant surface subsidences are commonly dish or bowl shaped and are termed sags. Method of Analysis The steps in analysis used to arrive at the proposed damage criteria are: 1. Canvas and rap subsidence damage in houses, 2. Assess the associated ground movements, 3. Estimate the damage repair cost, 4. Develop a damage/repair level classifica¬tion, 5. Correlate the associated ground movement, damage/repair level and home construction type, 6. Propose a damage criteria.

Jan 1, 1984

By T. W. Martin

The use of conveyors in large, open pit mines and their drawbacks are discussed. Technological developments such as long distance conveyors capable of handling large rocks are explored. The development and testing by the Bureau of Mines of a prototype crib and cable conveyor for handling large rocks are discussed, and possible modifications of the concept for a production model are examined.

Jan 1, 1984

By R. H. Ring

The Automatic Extraction System (AES) was designed and built under a U.S. Department of Energy Contract by the National Mine Service Company in cooperation with the Lee Engineering Division of Consolidation Coal Company. The Pennsylvania State University, Mining Engineering Section, was contracted as an independent auditor of the AES performance. The AES had a rotating cutter drum like a continuous mining machine; but two hydraulically powered roof supports, four roof-bolting drills, a dust scrubber, a ventilation fan and ducting in the roof supports, semi-automatic control, an extensible chain conveyor, and other innovations led to the distinction "extraction system" as opposed to "miner-bolter" or "continuous mining" machine. After design and assembly, the AES was field tested experimentally in an underground coal mine. The in-mine performance audit was preceded by a computer simulation of the potential production for a later comparison with the actual tonnage mined by the AES. This paper describes the results of an in-mine trial and assesses the production potential of the AES.

Jan 1, 1980

By George J. Skoronski

The economics of pellet plant operation, in terms of fuel and power consumption, flexibility in the selection of the cheapest fuel source, system availability, maintenance costs, and the simplicity of process design, contribute to the determination of building and profitably operating a pellet plant. Design innovations, sup- ported by actual field data, have been initiated into the GRATE-KILN System design to positively address these factors. This paper presents the recent state of the art design concepts which have helped the GRATE- KILN System assume worldwide acceptance status.

Jan 1, 1983

By LeRoy D. Loy

To facilitate effective land reclamation and comply with existing state regulations, surface coal mine operators have in recent years adopted new mining techniques and equipment utilization for steep-terrain mining. In contrast to direct spoiling with draglines or shovels, these new mining methods require some form of overburden haulage from the excavation face to the point of reclamation. Although current mining methodologies such as Block-Cut, Modified Block-Cut, and Mountaintop Removal with Head-of-Hollow Fills have proven effective in achieving reclamation objectives, some production problems have resulted from pit congestion and excessive equipment delays. Recognizing this problem, the United States Bureau of Mines contracted Skelly and Loy to design innovative mining concepts utilizing conveyor haulage in place of trucks, loaders, dozers and scrapers. Project objectives required definition of current bottlenecks and development of mining systems to: alleviate bottlenecks; increase production potential; facilitate additional resource recovery; enhance reclamation; reduce safety hazards; and improve mining economics. Successful completion of project goals within a four year program involves systematic implementation of the following separate work phases: 1) Develop Concepts for Block-Cut Mining Systems; 2) Determine the Economic and Technical Feasibility of Concepts; 3) Prepare Detailed Design and Specifications of Concepts; and 4) Prepare Specifications for Conducting Field Tests of the Most Promising Concepts. At the time of this publication, Phases 1 and 2 are finalized with Phase 3 efforts well underway.

Jan 1, 1977

By Victor J. Scaravilli, C. Richard Linamen

This paper presents a case history of Southwest Interceptor Contract No. 1, Cleveland, Ohio. It details some of the problems and solutions of handling and erecting precast concrete segments in a small bore soft ground tunnel. It also reviews how specific interpretations of contract requirements and contract administration effect production, performance and productivity.

Jan 1, 1987

By B. E. MacNab

During the past several years, Raymond Kaiser Engineers has prepared numerous studies concerning the technical and economic feasibility of coal exporting facilities in the western United States. Perhaps the most striking conclusion to be drawn from these efforts is that many people underestimate the complexity of the highly competitive, dynamic coal marketing system which includes coal loading terminals as an essential but relatively low-cost link in the energy production and delivery chain. The title of this paper, "The Status of Western United States Coal Ports - An Economic Assessment," should not delude anyone into thinking that the future of western U.S. coal- exporting ports has now congealed into a well- defined economic plan. As this paper will demonstrate, the situation is complex and more dynamic than ever and promises to remain so into the late 1980's.

Jan 1, 1982

By B. N. Thompson

The main industrial minerals produced are non-metallic - clay, dolomite, limestone, pumice, salt, serpentine, and silica sand. The other minerals, some with minor production, include diatomite, feldspar, magnesite, sulphur, asbestos, and perlite. Energy and metallic minerals and aggregate are excluded from this account. These industrial minerals occur in a wide range of rock types and geological ages. For example clays are known from the weathering products of Cretaceous rhyolite and leaching of Eocene coal measures; from Quaternary weathering of contemporary loess and shallow marine sediments, and of greywacke of Triassic-Jurassic age; and from the hydrothermal alteration of Late Cenozoic acidic volcanic rocks.

Jan 1, 1982

By Rod L. Norfleet

Cemented tungsten carbides are a sintered powder - metallurgical product essential to modern industry. Because of their moderate unit price and our dependence upon foreign sources for the component raw materials, a growing recycling industry has developed in the United States. There are two basic approaches taken to recycling cemented carbides; those which leave constituting materials unaltered or direct-reuse and those which separate the constitutes back to the raw components. To separate the carbides back to their raw components usually requires expensive chemical processing and is thus confined to the lower value materials such as grinding sludges. The direct-reuse methods recycle cemented carbides back to an intermediate level, a powder capable of being recompacted and resintered into a functional end-product. The three most commonly used methods of direct-reuse recycling, the coldstream process, bloaching and the Bernard or zinc process, are reviewed,

Jan 1, 1984

By Kaixi Jiang, Chaozhen Zheng, Shuchen Qin, Hao Ma, Yufang Wang

The study investigates the behaviors of zinc and iron in neutralized residue during pressure and hot acid leaching. It examines the effects of temperature, acidity, leaching time, and oxygen partial pressure on zinc extraction. The results indicate that the acid to zinc mole ratio is crucial for the extraction process, with a zinc extraction rate reaching 98.0% under optimal conditions.

Feb 14, 2022

By Raymond A. Povirk, David L. Bartsch, James V. Hamel

The Ohio Valley Coal Company is expand- ing its Powhatan Mine No. 6 near Alledonia, Ohio. This expansion includes a 20 rn (65 ft) height in crease for an existing 44 rn (145 ft) coal refuse - slurry impoundment dam. The dam is being raised by upstream construction which will involve placement of more than 15 m (50 ft) of new fill over an existing reinforced concrete decant structure. This structure is 0.76 rn (30 in.) square inside and its deepest portion was under 24 m (80 ft) of coal slurry and water. The top of the decant structure was not strong enough to safely support the new fill and, because of the slurry and water, there was no way to reinforce the structure from the outside. The structure was reinforced frorn the inside by sliplining 73 m (240 ft) of 0.66 rn (26 in.) OD, 0.53 rn (21 in.) ID polyethylene pipe, grouting around this pipe with cellular concrete. and constructing a steel-fiber reinforced micro-silica concrete transition at the upslope end of the pipe. Rehabilition of the decant structure was completed in August 1989. The rehabilitated decant structure is now performing satisfactorily as fill is being placed over it for raising the dam.

Jan 1, 1991

By Stanley N. Watowich

Recently the petroleum market has made us aware that we are indeed global natural resource consumers, and as such, we have become captive to fundamental global resource economics and their attendant vagaries. Global resource supply problems are as old as civilization and mineral exploration one of its important catalysts. On the basis of natural resources empires have been expanded and new frontiers have been developed. Global consumption and production might even be viewed idealistically as a system dedicated to optimizing distribution to the consumer. However, this is not the case. Political instability and increased government polarization make dependency on a global market somewhat insecure. The U.S. must evaluate its domestic mineral re- sources on the basis that all metals are critical and that dependency on even the common and base metals may ultimately weaken our domestic economy and our potential international relationships and could cause critical weaknesses as demonstrated by the petroleum problem. This paper evaluates specifically the Duluth Gabbro Complex, of Northeastern Minnesota, (figure l), as a potential resource of critical and strategic metals. First, a chronology of some of the early exploration, will be followed by more recent intensive company studies and preliminary evaluations of economic feasibility. Lastly, metallurgical data, on some optimum conceptual mining plans will allow metal production data to be compared with an estimate of U.S. domestic needs in 1990. The purpose of this paper is to put into focus the difficulty of converting resources into vitally needed reserves.

Jan 1, 1981

By Adrian C. Dorenfeld

Concentradora "Dana Aida" (100 t/d capacity) was built in 1971-1972 to treat dumps and ores containing mixed oxide-sulfide copper-gold-silver minerals from two veins. The veins, Don Felipe and aria are about 150 m apart, but are distinctly different mineralogically. The deposit is near San Juan de Guadalupe, Durango. Mexico. All new process equipment was manufactured locally, in or near Torreon, Coahuila. Sampling, ore testing, flowsheet design, plant design, drawings purchasing, financing, etc. was planned and directed by two engineers. Construction was executed by local miners and common labor (largely agricultural). The paper presents detailed costs for equipment and construction. The subsequent breaking-in operation is discussed.

Jan 1, 1979