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By William C. Grady

The environmental and economic problem created by pyrite in coal are well documented. The removal of pyritic sulfur prior to, or during, utilization has been the object of considerable research, however, much of this research has proceeded without a proper knowledge of the microscopic occurrences of pyrite in coal. This paper investigates the forms, occurrences, and variations in the distribution of pyrite in major West Virginia coal scan. Twenty-nine samples from twenty-two major west Virginia coal scans were selected for this study (see Table I). The samples were selected so as to be representative of the major coal producing areas of the state. All samples, except five, were collected at active surface mines, as indicated in Table I, and all except one were channel samples. The time interval between sampling and preparation of polished microblocks varied from two months to two years, though most were prepared within three months of collection. Grinding, screen¬ing, and riffling of samples to obtain 250 grams of -20 mesh coal for microscopic analysis strictly followed ASTM procedure D2013-72.

Jan 1, 1976

By E. Harrison

The Greens Creek Ore Bodies are located approximately 18 miles southwest of Juneau, Alaska in an area on Admiralty Island classified as a non-wilderness national monument. An area-wide stream sediment geochemistry program targeted the deposit in October of 1973. Today, after 37,000 meters of combined surface and underground diamond drilling, three ore zones are known to exist with total reserves approaching 4.1 million tonnes. Lying within moderately folded metasediments of an undetermined age, these orebodies are thought to be of seafloor exhalite orgin and contain unusual and impressive amounts of gold, silver, lead, zinc and copper.

Jan 1, 1986

By A. V. Castelli

Weighting materials as we know them today were first recognized in 1922 by B. K. Stroud1. Stroud, who was supervisor or the Mineral Division of the Louisiana Department of Conservation, tested galena, cement and hematite as weighting materials and successfully used hematite to make a "heavy mud". The first use of barite was in the fall of 19222 . The process of adding heavy minerals in mud was patented in 1926 by Stroud and National Pigments and Chemical Company, a subsidiary of National Lead Company now NL Industries, Inc. The ground barite was marketed as BAROIDR barite.

Jan 1, 1983

By Larry B. Bramlett

Regional radiometric, magnetic and geologic data point to Copper Mountain as an area of general uranium favorability. Sub-regional radiometric and magnetic data direct interest to a specific section of an overthrust Precambrian granite. Detailed magnetic and resistivity surveys in this area show local targets of interest, one of which corresponds to Rocky Mountain Energy's North Canning deposit. On the basis of these data a second and previously untested target was drilled resulting in the intersection of uranium horizons similar to those at North Canning. This integrated geophysical approach can be used for uranium exploration in geologically similar areas.

Jan 1, 1979

By D. W. Park

Underground room-and-pillar mining operations in the Warrior Coal Field in Alabama frequently suffer instability due to soft floor and thinly-laminated immediate roof. The investigation covered by this paper concerns a mine that was experiencing ground-control problems with weak floor conditions. Four hundred ft above the presently producing seam, another seam has been mined out. Several roof falls occurred locally, and as much as two ft of floor heaves have been experienced. The paper presents the results of comprehensive analysis conducted on floor heave, roof sagging, and the influence of the mined-out seam using instrumentation and numerical analysis.

Jan 1, 1991

By G. M. Rao

It has been a universal observation that rich grades of ores and minerals are getting depleted, simultaneously the demands for civilization are ever increasing coupled with occurrence of poor grades of ores and minerals posing a problem to the processing engineers. At the same time, the cost of mining and milling are increasing, creating a situation where the management has to handle and process low grade ores at an economic level keeping environmental stipulations and control to be safeguarded which has been an additional cost for the management to comply with.

Jan 1, 1994

By Bruce F. Bohor

Silica sand has been mined in Illinois from the St. Peter Sandstone since the turn of the century, especially in the area around Ottawa on the Illinois River in the north-central part of the state. Production of this sand, consumed mainly by the glass and foundry industries but also sought after for many other uses, has grown with the economy, and last year's output in Illinois exceeded 4,000,000 tons. Such an important commodity was given the early attention of the Illinois State Geological Survey, and a very complete report was issued in 1928, authored by J. E. Lamar. The mining and processing of the sand has changed very little during the intervening 40 years, so that much of Lamar's data and descriptions are applicable today. More recently, the stratigraphy of the St. Peter Sandstone in north-central Illinois has become better known from the work of Willman and Payne (1942). The present authors have borrowed generously from Lamar's publication, and we wish to acknowledge the contribution of both of these studies to our work.

Jan 1, 1969

By J. LeRoy Peterson

This paper presents some of the theoretical aspects as well as some results of actual plant operation of the Ty-Hukki Classifier. Dual classification steps within a unit vessel are achieved by controlled separation of the sand product under turbulant flow conditions, followed by further classification under strictly laminar flow conditions. Plant operation has shown some of the benefits of the superior sharpness of classification to be reduction of circulating load in grinding circuits, prevention of overgrinding, increase in mill feed rate and consequent reduction in cost per ton of ore.

Jan 1, 1966

By F. Robert Hollo

Programmable controllers have achieved remarkable acceptance over the relatively few years since their introduction. They provide some unique advantages over conventional relay and solid-state logic, which they often replace. Programmable controllers are discussed in both conceptual and functional terms, followed by an exploration of their applicability to material handling tasks with particular emphasis on conveyor systems.

Jan 1, 1973

By S. C. Howell

The mining of taconite, to provide feed for a processing plant, requires that the flow of material continue uninterrupted. This means first, that the crude must be of a size acceptable to the primary crusher in order to reduce the delays caused by plugging the crusher with chunks. Secondly, elimination of oversize in the pit will reduce costs of all wear parts used in the mining and processing of taconite. Savings in wear parts is readily recognized in dipper teeth, bases, buckets, truck boxes, and crusher parts, both primary and secondary. During the early days of taconite mining, it was soon recognized at reserve mining company's Babbitt operations that experience in mining other ores was not always (or ?necessarily??) Applicable to excavating taconite. This was especially true in drilling and blasting. Blasting of small tonnages in single or double rows simply filled the pit with scattered chunks and provided very shallow banks for shovel loading. It also created problems for the jet piercers, since all drilling had to be performed in fractured areas. Drilling efficiency suffered and costs were extremely high. Shovel and truck efficiencies were also low and again costs were high. A high percentage of secondary breakage was required. This necessitated the use of numerous man hours to jackhammer holes in chunks, preparatory to loading and blasting. After the chunks were reduced, bull- dozer and grader hours were needed to pile the taconite for acceptable shovel loading.

Jan 1, 1968

By Reed J. Irvine

One normally does not find sudden and dramatic changes in the investment climate, barring the unexpected outbreak of-wars or revolutions. Asia has seen a fair amount of military action and revolt during the past year, not all of it unexpected There was the fighting in Laos, which resulted in the as yet unconcluded negotiations which will probably lead to the establishment of a neutralist regime. In April of 1961 another revolution occurred in South Korea, and the elected government was replaced by a military dictatorship.. Communist guerrilla activity in South Vietnam was stepped up, and uncertainty about the future of that area increased. Relations between Pakistan and Afghanistan became more strained, and while no fighting has broken out, diplomatic relations between the two countries were broken off. India was both the victim of further incursions of her territory by communist China and the perpetrator of the forcible seizure of territory from Portugal. Indonesia has been making preparations for an armed attack on the Dutch in New Guinea.

Jan 1, 1962

By Robert H. Poppe

The Regional Copper-Nickel Study examined the potential impacts of copper-nickel sulfide mining, concentrating and smelting operations in northeastern Minnesota and gathered extensive monitoring data on the ecological characteristics of the region's aquatic and terrestrial biota. Because of the many development options possible, the diversity of the region's ecology, and the uncertainty of future environmental regulatory requirements, the Study did not attempt to measure the magnitude of environmental impacts on specific biological communities from a specific development proposal. The Study provides a broad base of environmental resource and impact information that hopefully will assist mining developers and environmental regulators when assessing specific proposals in the future. The following discussion is not a description of what will happen if copper-nickel development occurs in northeastern Minnesota but an exploration of why certain potential aspects of such development should be carefully considered and adequately understood before unnecessary or irreversible decisions are made.

Jan 1, 1980

By Maribeth Amyot

This paper assesses the current status of computing education in ABET-accredited mining engineering programs in the United States. The hardware and software being used are reviewed. The extent to which computer applications are incorporated into mining engineering courses is also surveyed. Today's capabilities and practices are compared with those of the past to establish, trends in computing education. The concerns of mining educators regarding computers are addressed, as are views on the direction in which mining engineering programs appear to be heading in preparing students to meet the computing needs of industry.

Jan 1, 1985

By R. Bruce Thorndycraft

Pinson Mining Company was formed to develop a gold orebody located in northern Nevada near Winnemucca. A feasibility study was undertaken in 1979 by a consortium of three Toronto-based mining companies and a Reno-based exploration company. The study indicated a viable project with gold priced above $225 per ounce. A project manager, and mine and mill superintendents, were hired in late 1979 to expedite the development of a 1000 ton per day mine-mill complex. Plant design engineering was contracted with Industrial Design Corporation in Salt Lake City. Three experienced plant metallurgists representing Pinson were stationed in Salt Lake to guide the work of Industrial Design. Among the many design criteria spelled out by Pinson, foremost were bringing the mill on line as quickly as possible at minimum capital cost. Fourteen months after the beginning of design engineering, the completed Pinson mill became operational. Total capital cost, including mine development, was $18 million. The Pinson project has proved to be far more than viable; the entire capital cost will be recovered within 18 months of the mill start-up.

Jan 1, 1982

By S. Afrouz, C. Keles, E. Sarver, A. Greth

While respirable dust monitoring has long been done on the basis of mass concentration, it is increasingly recognized that specific dust characteristics may play an important role in health outcomes. Scanning electron microscopy with energydispersive X-ray (SEM-EDX) can be used for detailed particle analysis, but the quality of results can be dependent on the sample substrate; ideally, particles should be deposited on a smooth, uniform substrate like polycarbonate (PC). While direct air sampling onto PC filters is possible, this is not the standard approach in many situations. For example, in coal mines, polyvinyl chloride (PVC) filters are often used. They enable conventional mass-based analysis — of the total respirable dust, and the content of crystalline silica in this fraction — but are fibrous and thus not ideal for SEM-EDX or other microscopy. To address this issue, the current work tested a simple method to recover respirable dust particles from PVC filters and redeposit them to PC. Results generally indicated that recovered particles are representative of the original dust sample in terms of mineralogy distributions. Where this was not the case, the issue appeared to be with high particle loading density during SEM-EDX work rather than related to the recovery/redeposition method itself. This bodes well for applications where a single PVC filter sample could be used for nondestructive analysis to determine respirable dust mass and/or respirable silica mass, followed by preparation for SEM-EDX analysis to evaluate particle characteristics. The recovery and redeposition method might also be adapted for other applications, such as to enable the analysis of respirable dust samples collected by the continuous personal dust monitor (CPDM).

Oct 1, 2024

By Arthur A. Schweizer

A method to improve the quality of Magmnt zinc concentrates to become acceptable feed to an electrolytic zinc refinery. The magnesia content of zinc concentrates produced was too high due to particle locking with the sphalerite in coarse fractions. Regrinding of the concentrates to a very fine particle size and then refloating the sphalerite was chosen to eliminate a sufficient amount of the magnesia to make the concentrates acceptable.

Jan 1, 1981

By D. Marsh

The feasibility study for the Grasberg Block Cave mine, finalized in May 2008, indicated a production capacity of 160,000 tonnes per day. A rail haulage system was an integral part of the mine design. This paper describes the simulation process used in optimizing the design and discusses the key factors and variables that impact the capacity of the system. The final recommendations for the haulage level layout and associated equipment are also included.

Jan 1, 2010

By T. C. Eisele

The separating efficiency of a flotation column is largely limited by the degree of backmixing of tailings into the froth zone, and its recovery is limited by the degree of short-circuiting of feed to the tailings. Current columns are typically made very tall, on the order of 30-40 feet, in order to limit the effects of backmixing and short-circuiting. These effects can also be reduced in a much shorter column, provided that the flow in the column approaches plug-flow. In this work, horizontal baffles were shown to improve the performance of a 6-foot tall laboratory-scale flotation column treating a difficult-to-clean, heavily oxidized coal. Tests with variation in the position of the baffles showed that for the greatest benefit, baffles are needed both above and below the feed inlet. Tracer tests with a fluorescent dye water tracer showed that the addition of the baffles reduced the amount of feed water entrained into the froth at any given coal recovery.

Jan 1, 1994

By Alan D. Hoagland

The Flat Gap Mine is on Copper Ridge in the Appalachian Valley of East Tennessee, Large zinc orebodies occupy zones of solution and collapse breccias in lower Ordovician Kingsport limestone and dolomite, The principal ore mineral is sphalerite and the principal gangue is dolomite, The orebearing horizons are considerably more than 95% covered by thick residual clay, and geochemical prospecting under these conditions is an effective exploration technique which played an important role in the discovery and exploration of the Flat Gap Mine, The residual nature of the over-burden at Flat Gap is emphasized, Background heavy metals (mainly zinc) range from 50 to 200 ppm, and the anomalies range to 3000 ppm and more, About 80% to 9W0 of the soil zinc is in relatively insoluble form in solid solution with the hydrous iron oxides and in the crystal lattice of the clay minerals. Quite discrete zones in the soil with sharply contrasting metal value boundaries mark vestiges of bedrock mineralization, and such anomalous soil areas are often contiguous with partially weathered ore. It has not been possible on the basis of chemical criteria to distinguish between an anomaly formed from non-commercial mineralization and one formed from ore.

Jan 1, 1962

By John W. King

reserves are exploring to increase them.. Uranium exploration projects are known to be active or planned also in Guayana, Colombia, Ecuador, Peru, Chile, Bolivia, and Uruguay in South America; in the UAR, Nigeria, Angola, Mozambique, Malawi, Kenya, and Somali in Africa; and in Greece, Iran, Pakistan., Indonesia, and New Zealand. The above list, to which several might be added makes a total of at least 43 nations actively interested in exploration for nuclear raw materials. As we consider the distribution of the world's uranium resources, it is interesting to note that roughly one third of the total occurs in deposits that are economically dependant upon another product. The very large reserves of South Africa could not be produced for uranium alone, but gold has carried a sufficient part of the total cost that uranium can be recovered profitably. Approximately 40 percent of the US reserves, or 120,000 tons, are estimated as by-product recovery from porphyry copper and phosphate operations, but these reserves are not presently in production. The remaining two thirds of the world's uranium reserves have been sought, developed, and produced primarily for their uranium content. Those deposits are estimated to contain 613,000 tons of uranium oxide recoverable at less than $10 per pound. Nearly half of that uranium occurs in unmetamorphosed sandstone hosts, mostly of late Phanerozoic age--the Colorado Plateau type. About 30 percent is contained in the quartz pebble conglomerates of southern Ontario, Canada, and 20 percent is in magmatic-related deposits--veins, contact deposits, mineralized breccias, etc.

Jan 1, 1969