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By W. C. Dailey

The Groveland Mine. Concentrator and Pellet Plant are located in Dickinson County in the Upper Peninsula of Michigan. The construction of the Groveland Mine in 1959 was the first United States operation for the Hanna Mining Company in mining and beneficiating low grade iron formations. (1) The plant produced concentrates at 675,000 lt/yr. (746,600 mt/yr.) which was used as sinter feed in the steel industry from 1959 to 1963. Upon completion of a pelletizing plant in April, 1963 production increased to 1.6 million lt/yr (1.77 million mt/yr) of pellets. After the plant expansion, mill capacity increased to 2.2 million 1t/yr (2.43 million mt/yr.), producing 2.0 million It/yr (2.23. million mt/yr.) of pellets assaying 63.0% iron and 7.0% silica. (1) Prior to April, 1971 the concentrator operated with a flowsheet consisting of spirals and a petroleum sultonate iron notation circuit. This was presented in a paper by R. R. Smith and E. E. Sougstad, "Flotation at the Groveland Mine" in the 50th Anniversary Volume entitled "Froth Flotation". The ore body at the Groveland Mine consists basically of two types of iron formation (34% total iron, 20% magnetic iron head), the most abundant of which is a bedded magnetite-chert-silicate rock. This is intermingled to varying degrees with non-bedded to poorly bedded hematite-clastic quartz-chert rock. (1) In developing the Groveland flowsheet, Humphrey spirals were used because of their ability to produce a coarse size concentrate at a low cost. Tests run in the lab and pilot plant on the Groveland ore showed a. spiral weight recovery in the 27 to 33% range. (2) However as the ore body was opened up, it became evident that the most abundant ore type did not liberate at the coarse size fraction needed for spirals. Plant recoveries for the first five years operating the spirals only averaged from 10 to 15% weight recovery. In 1971 the weight recovery on the spirals had dropped to a low of 5%. To increase iron recovery and at the same time increase plant capacity with the least effect on the present operations the mill flaw-sheet proceeded from a spiral-notation circuit to an all flotation circuit to a magnetic separator-flotation circuit. During this changeover the concentrate grade also had to be improved to meet market demands. To do this the following changes evolved

Jan 1, 1978

By T. M. Barczak, Zach Agioutantis

The Support Technology Optimization Program (STOP) has been developed by the National Institute of Occupational Safety and Health (NIOSH) to provide a comprehensive tool for evaluating the performance of available secondary roof support systems and designs based on support strength, convergence, cost, installation time and material handling considerations. This program uses engineering models developed from full-scale testing of numerous supports under controlled loading conditions in the unique NIOSH Mine Roof Simulator load frame to determine the support load-displacement performance as a function of the various sup- port design parameters. Both standing supports, such as wood cribs installed within the entry, and intrinsic supports such as cable bolts, can be evaluated. Support systems can be designed and compared for use in a new mining section or to evaluate potential replacements for an existing design. The support design requirements are defined from 1) estimating the failure height in the immediate roof, 2) in-mine measure- ments of support and strata interaction or development of ground reaction curves from numerical modeling, 3) the performance of an existing support system, or 4) from any arbitrary load and convergence criteria. All settings can be saved to permit resuming an evaluation in progress at a later time. This paper presents the updated MS Windows version of this tool, which can be easily installed and run on a personal computer. This Windows implementation will feature a project and application scenario setup where multiple scenarios can be assigned to one project. Scenarios can then be compared on support parameters and cost. Cost parameters can be provided either as individual cost items or using a price grouping feature. Additional support performance curves and/or additional ground reaction curves will be distributed with program updates as new information is developed. Users can also provide their own support and/or ground reaction curves.

Jun 25, 2024

By P. B. Altringer

The Bureau of Mines, U.S. Department of the Interior, is investigating biodegradation of cyanide as a means of decommissioning heap leach operations. Biological oxidation decreased weak acid dissociable (WAD) cyanide in process solutions1from 50 to 170 ppm down to 0.1 ppm. The tests were conducted both in trickling column reactors, using quartz as the growth surface, and in upflow columns, using activated carbon as the growth surface. In addition, exploratory tests indicated that bacteria will destroy residual cyanide in leached ore. A flowsheet has been proposed for closure of heap leach operations in which the metals processing portion of the plant, possibly the carbon adsorption columns, or a collection pond is used as a bioreactor. The cyanide in the process solution is destroyed in the bioreactor and the treated water is used to rinse residual cyanide from the spent heaps. The water is recycled until the effluent WAD cyanide concentration meets discharge standards.

Jan 1, 1992

By E. A. Metz

It has been approximately four years since the International Agency for Research on Cancer (IARC) reclassified crystalline silica as a "group one" substance. Since then, crystalline silica has been considered a human carcinogen. Silicosis is a preventable disease, and several aggressive campaigns have been developed to increase awareness of silica-dust-related problems in the industrial environment. New analytical techniques are now being developed to determine quantitatively the amount of crystalline silica in materials. Yet, still much is to be learned about the surface properties of silica and the way in which the disease progresses into full-blown silicosis. This paper discusses the interaction of free radicals generated by the mineral particles and lung tissue. It is the cell injury and DNA damage that progresses to fibrogenesis. Freshly fractured surfaces of silica contain free radicals. These free radicals play an important role in the stimulation of the alveolar macrophage and the development of the inflammatory reactions leading to the fibrotic response caused by silica. Engineers, scientists and physicians need to discuss the mineralogy of silica and the technical issues concerning the development of silicosis.

Jan 1, 2000

By R. Reeves

Coal producers and utilities depend on automated coal blending systems to reduce costs and meet stringent environmental regulations. Over 30 systems installed in the United States since 1987 use on-line PGNAA (Prompt Gamma Neutron Activation Analysis) analyzers to accurately control the blending process. Experience and detailed engineering are required to integrate real-time data produced by the coal analyzer with a control system to meet demanding performance specifications. This article reviews successful installations and lists important features including interfacing analyzers with plant control systems, specifying feeders and weigh scales, and managing data.

Jan 1, 1995

By Palmer C. Sweet

By-products from mining and processing plants and coal-fired power plants are being utilized more as valuable resources in Virginia. Mining-related by- products are divided into two categories: those generated from mineral extraction and beneficiation, and those generated from mineral processing or from industrial plants. Materials from both categories are produced in Virginia, where by-products have been exploited for various uses in the past and/or present. These materials include coal- combustion products (fly ash and bottom ash), lime-kiln dust, flue-gas-desulfurization residue, rock fines, magnetite, Cold Spring clay (kaolin), Austinville tailings, soapstone rock, and calcium-carbonate paste. Some of these by-products have never been utilized, although several ideas have been investigated over the years.

Jan 1, 1999

By F. N. Kissell, N. I. Jayaraman

Dust scrubbers on continuous miners are steadily gaining in popularity. Recent US Bureau of Mines research on scrubbers is reviewed, with emphasis on development of a new type of water-powered scrubber that can be retrofitted to existing miners; comparison of scrubber effectiveness with blowing and exhaust line ventilation; and improving the quartz dust collection of flooded-bed panels.

Jan 1, 1991

By N. I. Jayaraman

Dust scrubbers on continuous miners are steadily gaining in popularity. Recent Bureau of Mines research on scrubbers is reviewed, with emphasis on the following areas: * Development of a new type of water-powered scrubber which can be retrofitted to existing miners. * Comparison of scrubber effectiveness with blowing and exhaust line ventilation. * Improving the quartz dust collection of flooded-bed' panels.

Jan 1, 1989

By N. I. Jayaraman

Dust scrubbers on continuous miners are steadily gaining in popularity. Recent US Bureau of Mines research on scrubbers is reviewed, with emphasis on development of a new type of water-powered scrubber that can he retrofitted to existing miners; comparison of scrubber effectiveness with blowing and exhaust line ventilation; and improving the quartz dust collection of flooded-bed panels.

Jan 1, 1990

By L. Frederick

Measurement of gamma radiation occurring in nature to characterize geological formations has been widely recognized in mineral exploration. Different methods and apparatuses have been developed for drill hole logging purposes. Geological formations vary in amount of naturally emitted gamma radiation. A gamma signature from a geological formation is captured by utilizing different types of gamma detectors. A natural gamma radiation detector (NGRD) can be used to control mining whenever there is a significant difference between the radiation levels in the mineral or ore being mined and the waste materials surrounding the ore. Surface miners, such as the one shown in Figure 1, can precisely control the elevation of the cutter as the machine moves over the surface of the formation. This type of machine is predominantly used in selective mining operations, e.g. surface coal mining. If there is a means to know the position of the cutter relative to the interface between the ore and waste, the miner can recover all or most all of the valuable mineral with very little out-of-seam dilution. This paper discusses the results of a successful application of gamma detectors to control a surface miner at one of North American Coal Corporations? locations - Red Hills Mine. The mine has nine coal seams in total with thicknesses ranging from 12? to 60?. The bottom six seams (Figure 2) are minable. The mine has complex geology and a significant amount of annual rainfall (4.7 ft). The mine produces approximately 3.5 million tons of coal and about 40 bcy of overburden per year. The operation utilizes diverse mining equipment including Dragline Marion 8200, electric shovel P&H 2800, Caterpillar end dump trucks CAT 785 and 789; bulldozers CAT D11, D10, D8, and D6. Coal is mainly extracted by utilizing a Wirtgen SM 4200 surface miner that is loading CAT 785 trucks with high volume coal bodies and payload of 150 t. Operational cutting depth is 24 inches with maximum cutting depth of 36 inches. Surface miner operators determine a cutting depth based on multiple cues, the most important being visual observations of a coal seam being cleaned or mined. The cleaning process involves removal of the last foot of waste material covering the coal seam. This is one of two critical phases in the coal extraction process. If, during the cleaning process, an operator sets a cutting head too deep, valuable product is wasted. If it is set too shallow, waste material is left to be mined with the coal. The second critical phase occurs in the last cut on the interface between the coal and waste material at the bottom of the coal seam. If the cutting head goes deeper than favorable, then waste material is delivered to a power plant.

Feb 27, 2013

By D. Wheeler

Similar to modern day petro-chemical processes, the flotation column is a complete break from the conventional manner of floating on a batch basis in cells. The column has a reputation of being only suited for cleaning applications, particularly that of molybdenum cleaning. The original column, invented and developed by Column Flotation Co. of Canada, Ltd., was developed as a Rougher-Scavenger. Only after proving its capability in this field was cleaning allowed. One rougher-scavenger column in closed circuit with a cleaner column produced better grade and recovery than a conventional cell plant consisting of one stage of roughing, two scavenging and four stages of cell cleaning. Three cleaner columns replaced 13 stages of conventional cell cleaning and resulted in higher grades and recoveries. The gentle countercurrent action of the column itself together with complete automatic control enable this machine to produce such results.

Jan 1, 1986

By J. E. Friant

The Mini-DiscTM cutter drill bit is a radical design departure from the traditional tri-cone rockdrill bit. Miniature disc type cutting tools as small as 3.25 inches (82.5 mm) diameter are fitted to a bit body to cut individual concentric kerfs. The action is the same as that commonly used on large tunnel boring machines but miniaturized. The high performance rate and efficiency of a disc cutter are the result of producing a large proportion rock chips rather than sand or powder. The Mini-DiscTM drill bit, referred to as the “Disc Bit” has other unique features as well. It can be re-greased between runs. It can be rebuilt in the field in about 15 minutes, cutters can be replaced and the Disc-Bit appears to require less down hole hydraulic power than conventional bits. Thoroughly tested in the laboratory, the bit has recently been undergoing field trials in well drilling, blast hole drilling and shaft drilling. As any engineer knows, the laboratory can not shake out all the problems but it eliminates the more glaring weaknesses. Performance results have been exhilarating, and a few mechanical problems were discovered and largely overcome. This paper is a progress report.

Jan 1, 1999

By J. E. Friant

The Mini-Disc TM cutter drill bit is a radical design departure from the traditional tri-cone rock drill bit. Miniature disc type cutting tools as small as 3.25 inches (82.5 mm) diameter are fitted to a bit body to cut individual concentric kerfs. The action is the same as that commonly used on large tunnel boring machines but miniaturized. The high performance rate and efficiency of a disc cutter are the result of producing a large proportion rock chips rather than sand or powder. The Mini-Disc TM drill bit, referred to as the "Disc Bit" has other unique features as well. It can be re-greased between runs. It can be rebuilt in the field in about 15 minutes, cutters can be replaced and the Disc-Bit appears to require less down hole hydraulic power than conventional bits. Thoroughly tested in the laboratory, the bit has recently been undergoing field trials in well drilling, blast hole drilling and shaft drilling. As any engineer knows, the laboratory cannot shake out all the problems but it eliminates the more glaring weaknesses. Performance results have been exhilarating, and a few mechanical problems were discovered and largely overcome. This paper is a progress report.

Jan 1, 1999

By R. A. Jankowski

Although the number of operating longwall mining systems has remained relatively constant, longwall production levels during the last five years have increased significantly. In the United States, longwall mining now accounts for approximately 50% of all underground coal production. While longwalls are highly productive and offer other advantages, operations employing this method of mining continue to experience dust-compliance problems. This increased longwall productivity has meant that far more dust is being produced. An improved understanding of the longwall face-ventilation system and the advancement of face-ventilation technologies are necessary to ensure all face personnel are allowed to work in an environment that is free of excessive levels of airborne respirable coal mine dust. The Dust and Toxic Substances Control Branch, National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory, examined several basic principles of the long wall face-ventilation system and has evaluated the effectiveness of numerous improved face-ventilation techniques for longwall mining systems. These include identifying improved techniques for measuring face-ventilation parameters on longwall mining sections and investigating the fundamental relationship between face airflow and the entrainment and dilution of respirable coal mine dust. Studies have been completed to determine the impact on face dust levels of using belt entry air to ventilate the longwall. Novel methods have been identified to increase the face air¬flow and to manage face airflow to effectively minimize dust exposure to face workers. Unique systems of auxiliary face ventilation have been developed and evaluated at full-scale, simulated longwall test facilities. The theoretical and applied aspects of each of these principles and technologies are discussed. Application of these results throughout the longwall mining industry, as documented from surveys conducted in the early 1980s and 1990s, have reduced the health hazard associated with excessive exposure to respirable coal mine dust.

Jan 1, 2000

By James L. Evers

Introduction There is a continuing search by government and industry for new mining methods that increase production, improve the working environment, reduce labor intensity, enhance recovery effectiveness, improve the reclamation process, streamline the flow of material, and reduce the unit cost. Hydraulic extraction and transport methods have outstanding potential in several of these areas. For example, hydraulic fragmentation produces a significant reduction in respirable dust. The inherent simplicity of hydraulic mining equipment and the resulting high reliability are recognized. Tool wear can be virtually eliminated. There is great flexibility in the size, shape, and orientation of the mineral deposit that can be mined. The cutting, gathering, and transport operation can be controlled remotely, providing more safety for workers. The threat of tool sparking and the resuiting dust or gas ignition are also eliminated. Although hydraulic mining was introduced in the US before the turn of the century, it has not gained the degree of acceptance found in other countries such as the Soviet Union, China, Germany, and Canada. The Hydraulic Mining Research program, initiated by the US Bureau of Mines in 1958, and the subsequent research by others has provided much of the basic technology required to spur the development of these methods into a viable extraction alternative. This article updates the development of hydraulic mining in the US. Particular attention is paid to monitor mining, the long-wall hydrominer, borehole mining, and the semi-autonomous mining system. Whenever the particular mining method is also being developed in other parts of the world, a brief description of the world-wide state of the art is given. Finally, allied studies designed to optimize these mining techniques are described. Hydraulic Monitor Mining Since 1958, the US Bureau of Mines (USBM), the Department of Energy (DOE), and other government agencies have funded more than a dozen programs to investigate the potential of hydraulic monitor mining. For this method, water is directed on the coal face from a monitor nozzle. Sufficient velocity is used to cause local fragmentation (Fig. 1). Coal particles are washed from the face to a trough. They are then flumed to a collection point. Oversized particles are directed through a breaker and then into the troughs. Monitor field tests were conducted in the 1960s in bituminous and anthracite coal at the following locations: • Rosylin No. 9 mine, WA (Nasiatka and Badda, 1963); • Rosylin No. 10 mine, WA (Price and Badda, 1965); • Sugar Notch mine, PA (Buch, 1964); • Thomson Creek mine, CO (Palowitch and Malinka, 1964); and • West Lebanon, PA (Fowkes and Wallace, 1968). In 1975, Ingersoll-Rand Research Inc. was awarded a two-year USBM contract to develop a continuous coal mining system using water jet fragmentation and

Jan 10, 1984

By William J. Miles, Raymond E. Blair

Introduction There has been much publicity of the boom and bust in oil and gas well drilling in the US, and many comments on oil and gas gluts. Despite this, the drilling industry remains the largest consumer of functional industrial minerals. The boom years of 1981 and 1982, compared with the bust year of 1983, show a sharp reduction in the consumption of industrial minerals-1981, 7.4Mt (8.2 million st); 1982, 6.3 Mt (7 million st); and 1983, 4.4 Mt (4.9 million st). Industrial mineral use rebounded in 1984 to 4.7 Mt (5.2 million st). This was the second highest year in history in terms of wells drilled and third highest in footage drilled. Table 1 shows the history of drilling activity and mineral consumption from 1971 to 1984. The uses of functional industrial minerals in oil and gas well drilling were detailed by Miles and Blair (ME, 1983, October, pp. 1397-1400). As an update, this article addresses only the changes that have occurred in the industry in the past two-and-a-half years. It will be directed to mineral use and new products introduced to the industry. Drilling practices A partial explanation of where wells are being drilled with lower quantities of minerals consumed is: • In the boom year of 1981, there was a proliferation of number of suppliers chasing the same business. This resulted in multiple sourcing, multiple warehousing, and a huge increase in inventory that became surplus in the following years. The bust year, 1983, caused a severe shakeout in the number of suppliers of minerals and associated drilling fluids. • In 1981 and 1982, the wild speculation in the oil and gas industry led to drilling of speculative deep gas wells. Oil wells were drilled on a wildcat basis - in areas of unproven productivity. • Presently, the oil and gas well drilling industry is very active. But drilling is directed toward proven areas of production and working over old wells for increased production. This means a large number of wells are being drilled with lower average foot-

Jan 11, 1985

By James McMaster

The Kamyr Countercurrent Tower Leaching Process is intended to combine, in a single tower, thickening, leaching, separation and clarification of pregnant solution, and washing of leaching chemicals from the tailing pulp. For a gold or silver metallurgical plant, the flowsheet would consist of crushing and grinding, cyclones for size control and partial thickening, the Kamyr tower, and a gold or silver recovery system of either carbon in solution, zinc precipitation, or direct electrowinning. Ancillary systems for the Kamyr metallurgical plant would include cyanide preparation, fiber preparation and recovery, and flocculant preparation.

Jan 1, 1990

By E. R. Bauer

In response to the mandates in the MINER Act of 2006, the National Institute for Occupational Safety and Health (NIOSH) conducted refuge alternatives research that included characterizing the utility, practicality and survivability of refuge chambers and outby safe havens. NIOSH also prepared and delivered a report to Congress in late December 2007 that summarized the findings of the re-search, included recommendations concerning the design and performance specifications for refuge alternatives, and focused on specific information that could inform the regulatory process on refuge alternatives. This paper highlights NIOSH?s research and recommendations concerning refuge alternatives, survivability evaluations of refuge chambers and presents a brief review of the current deployment of refuge chambers in underground coal mines in the U.S. The research has lead to the conclusion that refuge alternatives have the potential for saving the lives of mine workers if they are part of a comprehensive escape and rescue plan and if appropriate training is provided.

Jan 1, 2009

By E. R. Bauer

In response to the mandates in the MINER Act of 2006, NIOSH conducted refuge alternatives research that included characterizing the utility, practicality and survivability of refuge chambers and outby safe havens. NIOSH also prepared and delivered a report to Congress in late December 2007 that summarized the findings of the research, included recommendations concerning the design and performance specifications for refuge alternatives, and focused on specific information that could inform the regulatory process on refuge alternatives. This document highlights NIOSH's research and recommendations concerning refuge alternatives, survivability evaluations of refuge chambers, and presents a brief review of the current deployment of refuge chambers in underground coal mines in the U.S. The research has lead to the conclusion that refuge alternatives have the potential for saving the lives of mine workers if they are part of a comprehensive escape and rescue plan, and if appropriate training is provided. 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 Stephen Hoffman

The Environmental Protection Agency (EPA) is investigating approaches to control non-coal mining wastes. In May 1988, the EPA's Office of Solid Waste (OSW) released a document that outlined an approach to manage non-coal mining wastes and materials. This document was called Strawman I. It was a staff-level approach designed to aid the continued participation of interested parties and to enhance EPA's understanding of mining waste issues. EPA has been working with states, public interest groups and the mining industry to gather information and to solicit input on waste management approaches. The involvement of the states in the Strawman process has been coordinated by the Mine Waste Task Force of the Western Governors' Association and the Interstate Mining Compact Commission. Involvement of public interest groups has been coordinated through Colorado Trout Unlimited. And the participation of the mining industry has been managed principally by the American Mining Congress. In May 1990, EPA released Strawman II. It was based on comments submitted to the EPA on Strawman I and on information given to the EPA by interested parties since 1988. Strawman II is again a staff-level approach to protect human health and the environment from wastes and other materials associated with non-coal mining. In September 1990, meetings were held with public interest groups and the mining industry to discuss their comments on Strawman II. By early 1991, the EPA expects to make a decision on how to proceed with program development.

Jan 1, 1990