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By Laura E. Beverage

The Changes 2008 Brought -MSHA recently posted a PowerPoint to its website which shows statistical performance information for fiscal years 2000 to 2008. -Interesting statistics: Fatality rate in Coal dropped by nearly 30% (.0348 to .0246 per 10,000 workers)

Jan 1, 2009

By S. Kwon

When an underground excavation is created near to an instrumented measuring location, deformation at the location increases. The characteristics of this deformation increase, as well as the duration of the influence caused by the adjacent excavation, is dependent on parameters such as opening geometry and measuring location. In this study, neural networks were applied to investigate the deformation increase and the influence of each parameter on the deformation change derived from extensometer measurements at the Waste Isolation Pilot Plant (WIPP) site in New Mexico, USA.

Jan 1, 1998

By H. Ozturk

In this paper, the computer program ‘SHAFT’ developed for estimation of support requirements for circular mine shafts is introduced. Theory of support design is based on the analytical solutions of circular excavations under non-hydrostatic loading (Detourney and St. John1), and Lame’s thick-wall cylinder theory (Timoshenko6). For rock mass strength property determination Hoek-Brown failure criterion (Hoek et al.2) is used. Mainly two types of support, concrete and steel are taken into consideration as a support member. Program is written in Quick Basic language. Input parameters of the program are shaft radius, number of zones having the same properties along the shaft depth, and depth, unit weight, horizontal to vertical stress ratio, GSI, and uniaxial compressive strength of intact rock of each zone, and compressive strength and safety factor of support member. Output of the program is the graphical representation of shaft with the required support member and thickness throughout the depth of the shaft.

Jan 1, 2003

By W. L. Cornell

The Missouri lead ores are the only domestic sources of cobalt presently being mined and processed for other materials. They represent the best short-term solution for meeting up to 13 pct of the Nation's strategic and critical cobalt needs from domestic sources. Presently, the cobalt is lost as an impurity in the copper, lead, and zinc concentrates and in the mill tailings because the technology to recover it with minium impact on present production does not exist. This paper presents results of research, built upon earlier Bureau of Mines laboratory research, to enumerate the problems encountered in cobalt recovery from the copper concentrate under actual mill conditions; to present alternative solutions to these problems; and finally, to describe the best available technology for cobalt recovery within the imposed constraints. Mineralogical analyses showed the cobalt present as a distinct mineral phase, predominately siegenite, amenable to a physical separation method such as froth flotation. Flotation was chosen for recovery because of easy adaptation by the mills. Unit processes of grinding, conditioning, and flotation were studied individually and in concert, and a series of continuous tests were run based on the parameters developed to obtain engineering data for subsequent economic analysis. Overall cobalt grades of 3.00 wt pct at a recovery of 64.0 pct were achieved.

Jan 1, 1987

By C. J. Bise

One area of study for the Coal Mine Injury Analysis project was to illustrate how loss control can be used as a foundation for mine safety training. After an initial review of the principles of loss control, the instruments often used for worker/worksite appraisal, such as incident reporting, analysis, and investigation, workplace observation, worksite inspection, and safety audits and checklists were evaluated for their effectiveness. The findings were then applied to the continuous-miner worksite at several mines to modify the techniques for use in a highly dynamic man/machine work environment. Before the information gathered from the review of the various continuous-miner worksites was presented at the annual retraining sessions at five mines, a trainability analysis procedure was developed to separate training shortcomings from those problems resulting from improper equipment design or unsatisfactory working environments. Also, several microcomputer-based training programs were developed to aid in conveying the loss-control concepts to the trainees. Finally, the results from the implementation and evaluation of the loss-control-based training programs were documented, including the complete training script for one of the case-study mines. The procedures outlined in this study will aid mine training specialists in developing focused, pro-active accident-prevention strategies and training programs that are based on sound loss-control principles.

Jan 1, 1993

Three computerised sets of minerals information are being developed by New Zealand Geological Survey in co-operation with the Resource Management and Mining group of the Ministry of Energy: 1. Geological Resource Map: a file of information on the location, geology, geochemistry, production, and potential use of individual occurrences of aggregate, mineral, geothermal, coal, oil, and gas resources. The computer program can be used for search and retrieval of information and the production of maps and tables. The data is being published as a series of 1:250 000 maps with accompanying text and tables. 2. Minerals Bibliography: an index and retrieval system for mineral exploration related; open-file company reports, N.Z. Geological Survey files, scientific research publications and university theses. 3. Minerals WhoÆs Who: an annotated directory of geologists involved in mineral exploration, mining and research.

Jan 1, 1986

By A. E. Tercan, D. Mamurekli

Ordinary kriging on the assumption of a gaussian error distribution and indicator kriging were used to derive the probability that a given calorific value would or would not be exceeded by coal from an area of a deposit. The two techniques led to similar probability maps despite local differences; the lack of an absolute reference makes it impossible to judge which method is better for this particular application

Jun 19, 1905

By B. V. Johnson

The Federal Bureau of Mines has conducted research in support of the National Aeronautical and Space Administration's (NASA) Apollo program to acquire fundamental scientific and engineering knowledge of lunar-mineral resources for NASA's Office of Advanced Research and Technology. Equipment and techniques were developed to conduct soil shear tests in a simulated lunar environment. Shear tests performed with this equipment in ultrahigh vacuum and controlled laboratory atmosphere showed that simulated lunar soil increased in strength in the simulated lunar environment.

Jan 1, 1973

By V. Svalbonas

The process of grinding mill quality assurance brings with it associated truths and myths. When the mill quality assurance process took its first great steps forward in the late 1970s and early 1980s, they were in response to the conditions existing, in our industry, at those times. In the late 1990s, we are faced with different conditions, and problems, and need fresh solutions. Yet the system developed for the early 1980s has produced no new approaches for the late 1990s, becoming instead more hardened and entrenched. This lack of development and actual resistance to research is now costing the industry significant amounts of money in late start-ups and useless scrap loss.

Jan 1, 1999

By Han-Tao Hu

Keywords: RH refining process, flow of molten steel, two-phase flow, gas holdup, circulation rate, mathematical modeling A three-dimensional mathematical model for the flow of the molten steel in the whole degasser during the RH refining process has been proposed and developed with considering the physical characteristics of the process, particularly the behaviors of gas-liquid two-phase flow in the up-snorkel and the momentum exchange between the two phases. The fluid flow fields and the gas holdups of liquid phases and others respectively in a 90 t RH degasser and its water model unit with a 1/5 linear scale have been computed using this model. The results showed that the flow pattern of molten steel in the whole RH degasser could be well modeled by the model. The liquid can be fully mixed during the refining process except the area close to the free surface of liquid and zone between the two snorkels in the ladle, but there is a boundary layer between the descending liquid stream from the down-snorkel and its surrounding liquid, which is a typical liquid-liquid two phase flow, and the molten steel in the ladle is not in a perfect mixing state. The lifting gas blown is rising mostly near the up-snorkel wall, which is more obvious under the conditions of a practical RH degasser, and the flow pattern of the bubbles and liquid in the up-snorkel is closer to an annular flow. The calculated circulation rates for the model unit at different lifting gas rates are in good agreement with the determined values.

Jan 1, 2005

By Louis A. Carapella, William E. Shaw

Magnesium and its alloys have long been characterized as possessing limited capacity for mechanical forming at atmospheric temperatures prior to rupturing despite their outstanding performances in this respect at elevated temperatures. Responsible for this behavior are the fundamental facts that these hexagonal-type metals have comparatively few slip elements at low temperatures for any extensive deformation and that, at high temperatures, additional slip elements become operative, thus enhancing greater plasticity under strain. The transitionai point has been set at 2 25°C by Schmidl for single crystals, and at 250°C by Morel1 and Hanawalt² for extruded magnesium metal. In a recent X-ray investigation on poly-crystalline magnesium-alloy sheets, Barrett and Haller3 have revealed that, below the transitional tempelature, the initial plastic deformation proceeds mostly by a twinning action; that, above such a temperature, the action is mostly by slip. The deep-drawing performance of the magnesium + 1.5 pct alloy sheet† over a wide range of temperatures has been investigated by Weber and Vanden Berg,' and their results are presented in Fig I. It should be noted from this work that a maximum drawability of about 25 pct at room temperature has been obtained on this alloy under the conventional deep-drawing operations. For the same alloy, it is now possible to augment the cold drawability to about 40 pct by a process to be disclosed. Hitherto, this value has been obtained only by deep-drawing the alloy at around 230°C. That greater plastic flow is attainable at atmospheric temperatures on magnesium under certain deformational techniques was discovered by the authors6 in their analyses of plastic-deformational behaviors of pure magnesium. This fact is best illustrated in Fig 2 from the Har-greaves analysis6 performed by the authors under two different modes of loading. For direct test, a separate unstrained specimen was used for each load duration, whereas for the integrated test the same specimen was employed for all the five intermittent loadings so that the load duration was made additive throughout the investigation. The higher plastic flow-rate at room temperature, as designated by the Har-greaves constant S, was obtained by the integrated or intermittent loading procedure. The authors6 in further tests showed that, under such a procedure greater plastic flow was also realized with a progressive increase in deformatione 1 loads. These findings have been applicd

Jan 1, 1947

By William E. Shaw, Louis A. Carapella

Magnesium and its alloys have long been characterized as possessing limited capacity for mechanical forming at atmospheric temperatures prior to rupturing despite their outstanding performances in this respect at elevated temperatures. Responsible for this behavior are the fundamental facts that these hexagonal-type metals have comparatively few slip elements at low temperatures for any extensive deformation and that, at high temperatures, additional slip elements become operative, thus enhancing greater plasticity under strain. The transitionai point has been set at 2 25°C by Schmidl for single crystals, and at 250°C by Morel1 and Hanawalt² for extruded magnesium metal. In a recent X-ray investigation on poly-crystalline magnesium-alloy sheets, Barrett and Haller3 have revealed that, below the transitional tempelature, the initial plastic deformation proceeds mostly by a twinning action; that, above such a temperature, the action is mostly by slip. The deep-drawing performance of the magnesium + 1.5 pct alloy sheet† over a wide range of temperatures has been investigated by Weber and Vanden Berg,' and their results are presented in Fig I. It should be noted from this work that a maximum drawability of about 25 pct at room temperature has been obtained on this alloy under the conventional deep-drawing operations. For the same alloy, it is now possible to augment the cold drawability to about 40 pct by a process to be disclosed. Hitherto, this value has been obtained only by deep-drawing the alloy at around 230°C. That greater plastic flow is attainable at atmospheric temperatures on magnesium under certain deformational techniques was discovered by the authors6 in their analyses of plastic-deformational behaviors of pure magnesium. This fact is best illustrated in Fig 2 from the Har-greaves analysis6 performed by the authors under two different modes of loading. For direct test, a separate unstrained specimen was used for each load duration, whereas for the integrated test the same specimen was employed for all the five intermittent loadings so that the load duration was made additive throughout the investigation. The higher plastic flow-rate at room temperature, as designated by the Har-greaves constant S, was obtained by the integrated or intermittent loading procedure. The authors6 in further tests showed that, under such a procedure greater plastic flow was also realized with a progressive increase in deformatione 1 loads. These findings have been applicd

Jan 1, 1947

By Arun .. J. Basu

The paper introduces Intelligent Air Management (IAM) as the core activity of M&I Group of Companies (M&I) for providing a total solution to any air management problems for mining and mineral processing operations implementing a comprehensive systems approach through a world-wide network of strategic alliance partners and in-house engineering team and manufacturing facilities in Mississauga, Ontario, Canada. Recommendations for energy-efficient ventilation in a vibration and noise free environment are made with the patented and innovative solutions supported by extensive computational fluid dynamics (CFD) studies. The solution scope extends from an intelligent and integrated exhaust silencer to a complete ventilation sys-tem solution including inlet and outlet control design and ducting for diffusers and silencers.

Apr 1, 2005

Fine Coal Evaluation by Gravity Methods

Sep 13, 2010

By Richard J. Mainiero

The Bureau of Mines has developed a prototype nonincendive explosive rock-breaker charge that can be fired unconfined in underground bituminous coal mines without the danger of igniting a flammable atmosphere that might be present. At present, unconfined shooting in underground coal mines is prohibited, but there are situations where the use of such shots would yield an overall improvement in safety. The charge consists of l-1/2 lb of permissible water gel explosive in the form of a short cylinder 7 inches in diameter and 7/8 inches high, surrounded by a l/2-inch-thick layer of damp salt, and encased in latex rubber reinforced with cheese cloth. The latex rubber housing provides a charge package that is strong enough to resist rough handling yet is pliable enough to conform to an irregular stone surface. A charge of this shape was found to be more effective at breaking rock than charges with lined or unlined cavities. Incendivity tests in a gallery have shown that the prototype charge will not ignite a flammable methane-air atmosphere when fired. Rock- breaking tests made with limestone boulders indicate that the charge will satisfactorily break stone slabs weighing 1 to 2 tons, and that two or more charges might be effective for slabs weighing up to 10 tons. In cooperation with the Mine Safety and Health Administration (MSHA), a test protocol for the certification of these charges as "permissible" for use in flammable atmospheres is being developed.

Apr 1, 1982

By V. T. Dow

Although the titaniferous iron occurrences at Iron Mountain have been known since 1850, exploitation of the deposits has been discouraged by the metallurgical difficulties encountered in treating the complex magnetite-ilmenite material. Because of the intimate association of magnetite and ilmenite, the material is not amenable to known ore-dressing practices. During World War II, industries started moving south and west from the industrial East; iron-ore reserves in the East were being depleted at a rapid rate; and titanium came into demand as a pigment. Imports of ilmenite from India, then the main source, were practically suspended because of lack of shipping space. These factors created interest in possible exploitation of the Iron Mountain deposits as a source of iron and titanium.

Jan 1, 1961

By E. J. Gleim

A list of permissible mine equipment, tested and approved by the Bureau of Mines previous to January 1, 1942, was published in Bureau of Mines Information Circular 7207.3/ The list of that date was complete as to equipment then available and in current use. Information Circular 7240,4/ published as a supplement thereto, listed equipment approved curing the calendar year 1943. The present list is another supplement covering approvals issued during the calendar year 1943. The items are numbered to indicate the consecutive order in which each type of machine or device was approved in its particular classification. Thus, Information Circular 7207 gave 19 drills and drilling machines on the Bureau's active list. No additional approvals were given in 1942, but the three issued in 1943 bring the total to 22. Item 102, under Loading Machines and Conveyors, also appeared in Information Circular 7207, and items 120 and 124 appeared in Information Circular 7240. These numbers are repeated here to show that approvals were granted during 1943 for additional voltages on machines previously listed for one voltage only. Equipment listed in these circulars is approved by the Bureau of Mines only when found upon inspection and test to comply with minimum standards of safety as outlined in schedules prepared on the basis of many years of experience in dealing with safety problems of the coal-mining industry. The use of such equipment in mines known to be gassy, as well as in those that may become so, is earnestly recommended in the interests of safety. This circular is published so that the industry may be kept

Jan 1, 1944

By M. Kalin

"Ecological Engineering and Biological Polishing technology is a decommissioning approach for inactive coal, uranium and base metal operations. To improve acid mine drainage water some fundamental aspects of wetland ecology and sediment microbiology are combined, to provide conditions to allow for biomineralization of the contaminants.This paper summarizes the first records of microbial alkalinity generation in acid mine drainage through the utilisation of the ARUM process. The process requires that the seepage is at pH 4.5 where sulphate reducers utilize sulphate to produce hydrogen sulphide, which in turn precipitates with metals. The pH increase is brought about by alkalinity generating microbes.The ARUM process has been successful in increasing the pH from 2.5 to 7.0. Flow through reactors operated in the laboratory continuously for more than 60 days have removed Ni from 13 mg/L to < 0.01 mg/L. Design parameters are being developed for low flow rates of 5 L/min in a test system receiving seepage from a tailings.1.0 INTRODUCTIONAcid mine drainage associated with mining wastes poses a significant environmental problem. Conventional means to treat acid mine drainage (AMD) use chemical treatment system. Ecological Engineering technology uses natural biological means to curtail and ameliorate AMD during mine operations and at the time of decommissioning. The premise underlying Ecological Engineering technology is that AMD is the result of a natural process enhanced by mining activities. Therefore, in nature, a process providing a natural balance to AMD has to exist, which, when assisted through appropriate means, can counteract the detrimental effects of AMD on the environment. This process is microbial alkalinity generation which is known to occur in wetlands, lake and ocean sediments (Baas Becling et al, 1960)."

Jan 1, 1991

By Leslie F. Sawatsky

Raw water import requirements for oils sands mines depends mainly on factors such as ore processing rate, ore material characteristics, tailings processing technology, tailings storage systems, process water storage operations, the phase of tailings production, and non-recoverable seepage losses from tailings ponds. These factors can be readily quantified to calculate raw water import needs. Nevertheless, mine water balance continues to be misunderstood by some regulators, stakeholders and possibly even mine operators. Confusion over consumptive uses has led to a focus on recycling which is not necessarily applicable to a closed circuit water management system. Some water conservationists focus attention on raw water intake rules instead of the technical decisions that control consumptive uses. Typical oil sands mine water balances for various types of tailings operations, are analyzed to illustrate the effect of controllable and uncontrollable parameters as well as major options that need to be explored for reducing water demand. Uncontrollable parameters including tailings fines content, oil content of ore, connate water, mine depressurization water inflows and surface water hydrology. Controllable parameters include storage operations, advance water supply ahead of mining operations, type of tailings operation, net tailings pond seepage losses, and tailings impoundment operations. Potential reductions of raw water supply rates may be obtained by providing greater on-site storage to attenuate fluctuation in water demand, advance water accumulation prior to mine start up, early commencement of CT operations, thickened tailings disposal and paste technology. Water conservation measures should be focused on reducing on-site process water storage and water content of tailings material.

May 1, 2004

By N. Ahmed

The collection of hydrophobic particles in the froth phase in flotation has been studied. A continuous flotation cell was developed, in which the froth phase could be isolated from the pulp zone. Hematite particles, d80 = 87 µm, were floated in the pulp, using a conventional oleate collector, while glass spheres of similar diameter, d80 = 82 µm, were introduced in wash water added to the froth. Four samples of glass spheres, with contact angles between 0 and 82 degrees, were used. The results indicate that the efficiency of collection of the hydrophobic particles in the froth can be very high. The process is strongly influenced by the hydrophobicity of the particles and the surface area available for attachment in the froth. Recommendations for the flotation of particles in the froth phase are made, especially regarding the desirable hydrophobicity as reflected in the contact angle, the froth depth, the solids concentration in the feed to the froth, the air rate and the wash water rate.

Jan 1, 2001