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By Jerry B. F. Champlin

The successful injection of liquids into subsurface permeable formations for production stimulation, storage, or waste disposal requires a rapid, precise, and accurate method of determining the permeability of porous solids. This report describes a method and apparatus, developed by the Bureau of Mines, that use the principle of specific-volume permeametry. Calibration of the apparatus over a wide range of permeabilities and standardization of several apparatus constants have eliminated many of the tedious calculations and problems of manipulation common to some other methods. Improvements in reproducibility and accuracy have resulted from reducing experimental measurements to one parameter--time. Specific permeabilities of reservoir rock samples are determined directly from a chart that relates elapsed time to a permeability equivalent to that determined by bubble-tube measurements.

Jan 1, 1962

The Bureau of Mines human factors research program is directed toward reducing accidents and improving the overall efficiency of the person-machine environment interface found in surface and underground mines. The focus of the hum factors program therefore, is to insure that sound knowledge is available concerning human capabilities and limitations, and that this knowledge is applied to the design, of mining equipment, work tasks, and management procedures. The papers presented in these proceedings summarize some of the recent Bureau research in hum factors. The papers focus on two broad areas, human resource issues and human engineering of equipment, tools, and work procedures found in mines.

Jan 1, 1987

By T. Mal

A test system was developed at the National Institute for Occupational Safety and Health's ventilation test gallery for measuring airflow using a three-axis ultrasonic anemometer. The gallery war used to simulate face airflow conditions in underground mines having a blowing curtain. Airflow data, collected at multiple sampling locations between the face and the end of the curtain, were used to draw airflow profiles for different curtain setback distances, intake flow quantities and entry widths. In addition, methane was released at the face, measured at the sampling locations and displayed as methane distributions in the area between the curtain and the face. Entry geometry had a significant effect on airflow patterns, and the flow patterns affected the distribution of methane in the entry. Flow measured at and parallel to the face was a good predictor of methane dilution and removal within 0.6 m (2ft) of the face.

By Mary E. Cocklan-Vendl

Regulatory processes associated with development of major mining operations in Alaska and British columbia were evaluated using specific case studies. Included were one hard rock mine in Alaska (Red Dog Mine), one hard rock mine In British Columbia (Snip Mine), and one offshore gold dredging project in Alaska (WestGold SIMA). Based on a comparison of the three case studies, it became clear that the primary incentives for cost effective permitting are: 1) early and continuing coordination of proposed project plans, designs and schedules with key regulatory agencies and local area residents and 2) development of a sufficient level of baseline information on air quality, water quality, wetlands, endangered species, fish and wildlife, and socia-cultural conditions to support the required permit application. The U.S. permitting process worked in much the same way as the Canadian permitting process. Disincentives of mine permitting include high initial costs for baseline data gathering. However, a relatively high early investment resulted in more efficient permit acquisition and reduced long-term monitoring requirements. A common problem Identified was the inadequate supply of trained agency personnel with the requisite technical and permitting experience. This sometimes resulted in poor decisions and unnecessary changes in project plans and schedules.

Jan 1, 1993

By Terry P. Medhurst, Stuart A. MacGregor, Peter J. Hatherly

In addition to fractures and joints, compositional factors and bedding influence the strength of clastic sedimentary rocks. Rock mass rating schemes must therefore consider all of these factors. In this paper, a rating scheme for clastic sediments based on geophysical measurements is described. Geo-physical logging allows an approximation of rock com-position to be obtained and an assessment of bedding frequency and laminations. Velocity measurements incorporate the effects of fracturing. The rating requires scores for the intact rock, bedding/cohesion, and defects. These are combined to yield a Geophysical Strata Rating (GSR). Determination of the GSR is objective and repeatable. GSR values are typically between 20 and 80 and can be related to the Coal Mine Roof Rating.

Jan 5, 2007

By Claud Johnson, G. Roger Miller, Kristine M. Krajnak, Stacey Waugh, Oliver Wirth

Workers exposed to vibrating hand tools are at risk of developing symptoms such as cold-induced vasospasms, loss of tactile sensitivity, and loss of grip strength in the fingers and hands. These symptoms are known collectively as vibration white finger (VWF) or hand-arm vibration syndrome (HAVS). Symptoms of VWF or HAVS are in part due to repeated and prolonged peripheral vasoconstriction[1, 2]. The reduction in blood flow that occurs with vasoconstriction can result in oxygen deprivation (hypoxia) in soft tissues, such as nerves and muscle, and lead to functional and structural changes in these tissues. The present study examined muscle tissue to determine if vibration-induced changes in transcript levels and protein concentrations result in enhanced vasoconstriction and hypoxia. Manual dexterity was also assessed intermittently to determine if vibration-induced changes in cellular factors are accompanied by performance deficits. Methods An animal model was developed to study the biological and functional changes that occur in response to repeated segmental vibration exposures. In this model, the right paw of intact rats was exposed to a platform vibrated at a frequency 250 Hz and amplitude of 49 m/s2 to simulate the vibration characteristics of hand-held grinders. Three groups of 8 rats each were studied: a vibration-exposed group, an exposure-control group, and a cage-control group. Exposure sessions, with or without vibration, were conducted 4 hr/day, 5 days/week for 5 weeks. Manual dexterity was assessed intermittently during the 5-week exposure period with the Montoya stair-case test[3], which quantifies the rat’s ability to reach for, grasp, and retrieve small food pellets placed below the rat on different levels or steps. Following the 5-week exposure period, the flexor muscles of the right forelimb were collected for analysis of gene expression, protein concentrations, and immunohistochemistry. Results Vibration-exposure resulted in an approximate 2-fold increase in the expression of a2C and a1D receptor transcripts in flexor muscles (Figure 1). These receptors mediate norepinephrine-induced vasoconstriction in smaller arteries. Vibration-exposure also resulted in an approximate 2-fold increase in hypoxia-induced factor-1a (HIF-1a), a transcription factor that is expressed in response to tissue hypoxia. Western analyses demonstrated that restraint caused a decrease in a1-receptor protein concentrations in the flexor, but vibration-exposure prevented the restraint-induced reduction (Figure 2). Immunohistochemistry performed on flexor muscles (not shown) demonstrated that a1 receptors are primarily located in arteries; maintained levels of these receptors could contribute to prolonged vasoconstriction following repeated vibration exposure. The staircase test showed some performance improvement, or a training effect, in manual dexterity for the control groups but not the vibration-exposed group (Figure 3).

Jan 6, 2006

By John A. Kiefer

Ground fault and overcurrent protection criteria for coal mine a.c. distribution systems were examined under a Bureau of Mines funded investigation. The report begins with a literature review which discusses relaying topics including instrument transformers, ground-fault pickup methods, static relaying, and comparison of relaying techniques. A chapter on ground-fault relaying provides recommendations for maximum and minimum pickup levels as a function of maximum ground current and power system line-to-ground capacitance. Research in the area of phase overcurrent protection has resulted in a complete set of procedural recommendations for the selection and setting of overcurrent relays and current transformers, molded-case circuit breakers, and distribution system fuses in coal mine power systems. The final chapter, which discusses relay system maintenance, introduces a unique test set which was developed by KETRON and used to test the performance of relaying systems in coal mines.

Jan 1, 1980

By Gordon R. Sima, John L. Bennett, Roger L. King

Electric shocks are a serious problem in the mining environment. Because of extremely wide ranging use of electrically powered equipment in the mining industry, the hazard to personnel due to electrical shock and related injuries are not restricted to any single area but cover the entire spectrum of mining activity. Electrical accidents, resulting in personal injury, due to im- proper or complete lack of grounding of electrically operated mining machines, form a significant percentage of the overall electrical accident picture. The object of this paper is to describe methods of detection of unsafe electrical conditions with respect to the grounding of electrically operated mining equipment. It also includes a discussion of prototype instruments which effectively monitor the condition of the grounding safety devices currently in use on mining equipment and warn of dangerous conditions as soon as they appear. The paper is based on work accomplished under USBM Contract Number 50357115. The contract was initiated under the Pittsburgh Mining and Safety Research Center Program. It was administered under the technical direction of PM and SRC with Mr. Roger L. King as the Technical Project Officer. Mr. Daniel B. Dawkins was the Contract Administrator for the Bureau of Mines.

By Steven D. Wirch

Abandoned underground coal mine areas must either be sealed or ventilated to comply with federal mine regulations. Ventilation of these abandoned areas is often impractical due to roof falls and inadequate primary mine ventilation. If the area is sealed, a very complex ventilation system is set up. In which the gob "breathes" in and out due to barometric pressure fluctuations. The Gob Assistant is a computer program (for use on IBM compatible personal computers) which allows the prediction of air flows into and out of a sealed mine area. Gas flows with applicable control techniques are also modeled. This information is presented to the user who will decide which control technique, or combination of techniques will ultimately be applied. The Gob Assistant is an intelligent gob simulator that can reduce the guesswork involved in predicting the effects of sealing and control techniques before they are applied. This paper provides the fundamental principles upon which the Gob Assistant is based, verification of these principles, and an explanation of how these principles were integrated into the Gob Assistant.

Jan 1, 1988

By E. M. Cohn

The literature dealing with the electrical conductivity of solid dielectrics, including all its aspects and its relationships to other physical properties of these materials, is extensive and scattered in many books, phamphlets, and periodicals. It is believed that most of the important contributions to this field up to October 1943 have been listed and abstracted in this circular. Also included are some general references on static electricity. Methods of removing static charges are described; methods of and conditions for measurements of resistivity are discussed; equations for the calculation of resistivity are given; and methods of resistance measurements in Situ are reviewed. Data on the variations of resistivity with changing conditions as well as explanations for them have been collected, and three tables showing the resistivity of various dielectrics at different humidities are included. The appendix contains a short development of the mathematical formulation of the charging and discharging currents due to interfacial polarisation. INTRODUCTION Methods for Removing Static Electricity Of the various means employed for preventing or removing accumulations of static electricity in industrial processes, grounding is the most common and most generally effective. It is a precaution readily applied to stationary machines anti may often be utilized to good advantage to rid persons and portable equipment of an acquired charge. There are many situations, however, in which direct low-resistance grounding cannot be used, either because the charged bodies are insulators or are inaccessible, or because contact to a ground lead might give rise to a hazardous spark. If the charged body is a conductor, contact made to a neighboring conductor, even though the latter be insulated from ground and of relatively small capacitance, may also result in the occurrence of an incendive spark. In such instances, static electricity can sometimes be removed most satisfactorily by means of strong atmospheric ionization produced by radioactive material, X-rays, ultraviolet light, or A. C. high-voltage brush discharge. Where no danger exists from flammable

Jan 1, 1944

By William J. Campbell

The purpose of this investigation was to extend the analytical services which are required for Bureau of Mines programs in developing and evaluating high-purity materials. Determination of trace elements in minerals and ores as an aid in geochemical evaluation and prospecting was considered. Serious consideration should be given to the merits of using the avail- able fluorescent X-ray spectrographic instrumentation and techniques for determining trace elements. Limits of detectability for trace elements in metal, oxide, solution or mineral samples range from 0.1 to 100 p.p.m, depending on the element being determined, overall sample composition, and the complexity of the X-ray spectra; limits of detectability range from 0.01 to 1 microgram for elements that have been preconcentrated by a chemical or physical process, for example, by ion-exchange membrane.

Jan 1, 1962

By Parviz F. Rad

This Bureau of Mines report reviews laboratory and in-mine techniques for determining mechanical properties of coals, with special emphasis on the relationship between these properties and the minability of coal. An extensive bibliography is included.

Jan 1, 1973

By Wing G. Agnew, John A. Johnson

"INTRODUCTION This paper is one of a series being published by the Bureau of Mines pertaining to an investigation on the use of stemming in metal mines now being conducted at the Mount Weather Testing Adit. Its purpose is to compare the amount of dust and gases produced as a result of blasting charges of dynamite (1) in drill holes, (2) in bombs, and (3) in mud-cap or adobe shots.ACKNOWLEDGMENTSValuable assistance and advice on stemming were given by members of the staff at the Bureau of Mines, as acknowledged in previous publications. 4/TEST PROCEDUREThe results used for comparison in this report are from dust and gas samples taken after blasting (1) four regular test rounds with no stemming, (2) five bomb shots, and (3) two mud-cap or adobe shots.The four rounds were the standard 26-hole test rounds designed to break 4 feet of rock. The procedure for drilling and blasting these rounds is described in Report of Investigations 3509.Before the regular test rounds were blasted, about 1,200 bounds of fine rock was placed on the steel mucking sheets that covered the end of the adit track; the wails, hack, and floor of the adit were washed thoroughly; and the fine rock on the mucking sheets was completely wetted.Each of the 5 bomb shots consisted of 10 sticks of dynamite tied together and hung at midpoint of the adit, 8 feet from the fall."

Dec 1, 1942

By William A. Beck

This report describes the loading and transportation practices employed at the zinc-lead mines of The Eagle-Picher Co., Jo Daviess County, Ill., and Lafayette County, Wis. The report also gives a brief history of the Illinois-Wisconsin zinc-lead district and the operations of the company in the area. The diesel-powered, rubber-tired loading and haulage equipment is described and illustrated from the operational point of view only, and an analysis is made of the materials-handling system without going into health and safety factors. The costs per ton of the various components of mechanical loading, underground haulage, underground crushing, and hoisting for fiscal year 1960 are tabulated.

Jan 1, 1964

By Thomas W. Camm

The U.S. Bureau of Mines has developed a system for estimating mining and processing costs as a function of process feed rate with the objective of applying this system to abandoned mine tailings and to evaluate the benefits, if any, of metal recovery. Cost analysis was applied to the mine wastes of Smelterville Flats: an extensive area of mine tailings in the Bunker Hill Superfund Site with high concentrations of lead, zinc, and other sulfide minerals. Results from previous site characterization and metallurgical processing studies were used as the input for the cost analysis. This analysis indicated that processing this site at an optimum production rate of 3,500 short tons per day (st/d) could generate a positive cash flow.

Jan 1, 1993

By T. A. Sullivan

The processing of sweated aluminum electronic scrap was investigated to develop methods for recovering the aluminum and concentrating the other metals, including copper, lead, gold, and silver, into a product that can be separated by known methods. Two molten-salt electrorefining processes were developed and tested. The first process utilized a three-layer refining cell with a BaCI2-NaF-AIF3 electrolyte, which operated at 750° to 850° C. The second process used an all-chloride electrolyte of NaCI-KCI-AICI3 at 750° to 800° C, with separate anode and cathode compartments. High-quality aluminum was recovered that averaged 99.8-percent pure in the three-layer cell and 99.6-percent pure in the compartment cell. Over 94 percent of the aluminum was recovered with cathode current efficiencies of approximately 90 percent in both methods. The copper, lead, tin, silver, gold, and other metals were concentrated threefold in an anode product. Separation of lead and part of the tin by liquation from this product seemed feasible. The anode product was smelted to prepare a 96-percent copper bullion that contained 690 ounces of silver and 65 ounces of gold per ton, with 98 percent recovery of these values.

Jan 1, 1972

By William H. Pomroy

Fire on surface mining equipment is a serious hazard to life and property. The Bureau of Mines, through a program of contract and in-house research, has developed and in-mine demonstrated reasonably priced, reliable automatic fire protection systems to deal with this problem. This report reviews the development and subsequent testing of systems for haulage trucks, front end loaders, coal augers, dozers, drills, and shovels. A variety of fire sensors, extinguishing agents, and control systems arc discussed in the context of mine equipment designs and operating environments

Jan 1, 1980

By Douglas Milne

Most empirical and numerical approaches to design in rock mechanics incorporate rock mass classification. Numerical design methods generally use classification values to calculate input parameters for stress-based failure criteria. Empirical methods use classification to allow comparisons between similar rock mass conditions, generally based on a graphical design technique that differentiates stable and failed opening geometries. Classification systems are the best tool available for assessing rock mass properties; however, there are problems with classification systems that should be high-lighted. Rock mass performance can only be realistically estimated by coupling a unique description of the rock mass with known loading conditions. Current classification systems cannot provide a unique classification value. The weightings applied to quantify rock mass properties for classification can result in significantly different rock masses having the same classification values. These weightings have been proven effective for tunnel design and support, but classification systems are now used for many more applications. Rock classification systems evolved from a quick and easy field tool for estimating tunnel stability and support requirements. The need for a rapid field tool means that rock mass classification is relatively insensitive to improved methods of measuring rock mass properties. Problems with classification systems and their application are highlighted in this paper. These problems must be recognized and documented before improvements can be made. An understanding of the evolution of classification systems and their application for both numerical and empirical design approaches is invaluable in highlighting current shortcomings.

Jan 5, 2007

By H. D. Raymond

This report contains a summary of designs, specifications, costs, and schedules developed for a prototype oil-shale demonstration mining program to be undertaken at the Horse Draw site in the Piceance Creek Basin, Rio Blanco County, Colorado. The objective of the demonstration program is to assess the feasibility of extracting oil shale and associated saline minerals from deep, rich oil shale zones which occur within the central portion of the Basin. Four mining systems were specified for demonstration. These include (1) chamber and pillar mining with backfill; (2) sublevel stoping with backfill; (3) sublevel stoping with full subsidence; and (4) block caving. Commercial-scale designs for each system were modified and scaled down as required to achieve program objectives. The demonstration mine layout and design includes specifications for ore handling, backfilling, ventilation, dewatering, maintenance, and supply systems. A feature of particular interest in the design is the combination of block caving and sublevel stoping methods into a single unit for demonstration of subsidence mining systems in deep oil shale deposits. The report also contains a detailed breakdown of projected capital and operating costs for the demonstration mining program.

Jan 1, 1979

By Office of Public Information

"The Bureau of Mines was established in the public interest to conduct inquiries and scientific and technologic investigations concerning mining and the preparation, treatment, and utilization of mineral substances; to promote health and safety in the mineral industries; to conserve material resources and prevent their waste; to further economic development; to increase efficiency in the mining, metallurgical, quarrying, and other mineral industries; and to inquire into the economic conditions affecting those industries. The organic act of the Bureau, as amended by Congress and approved February 25, 1913, made it the province and duty of the Bureau of Mines to ""disseminate information concerning these subjects in such manner as will best carry out the purposes of this Act.""In accordance with this directive, the Bureau reports the findings of its research and investigations in its own series of publications and also in articles that appear in scientific, technical, and trade journals; in proceedings of conventions and seminars; in reference books; and in other non-Bureau publications. The number of these reports, the wide range of subjects they cover, and the variety of mediums in which they appear make the kind of list and index presented in this special publication both necessary and valuable.·This issue of the Bureau of Mines. List of Publications and Articles describes reports and articles published during the period January 1, 1985, to December 31, 1989. It supplements the 50-year list of Bureau publications issued from July 1, 1910, to January 1, 1960;1 the 50-year list of articles by Bureau authors published outside the Bureau from July 1, 1910, to January 1, 1960;2 the 5-year lists of publications and articles from January 1, 1960, to December 31, 1964,3 from January 1, 1965, to December 31, 1969,4 from January 1, 1970, to December 31, 1974,5 from January 1, 1975, to December 31, 1979;6 and from January 1, 1980, to December 31, 1984.7"

Jan 1, 1990