Search Documents

By A. N. Baldwin

This report documents work performed under Bureau of Mines Contract J0265029 to study and develop two innovative mining systems: ? An underground auger capable of augering into the right and left ribs without repositioning the machine ? A conventional mining system employing recently developed innovative machinery. The report is separated into two volumes to document the two studies separately. Volume I describes work performed and the recommended concept for a bidirectional auger. Volume II describes the studies of mining equipment performance and mining plane developed to determine a conventional mining plan offering improved productivity.

Jan 1, 1977

By Jérôme Boutin, Rémy Oddo, Sylvain Ouellette, Paul-Émile Boileau, Gilles LeBlanc, Pierre Marcotte

ackleg rock drills are widely used in the mining industry and are known to generate high levels of hand-arm vibration which contribute to the development of the hand-arm vibration syndrome for exposed miners.1-3 To reduce the vibration levels, a prototype of an antivibration handle was developed as part of a previous study.4 To provide some bench marking for this handle prototype and to follow the evolution of its performance over time, a test bench was developed to characterize the vibration emission values of jackleg drills under controlled operating conditions. As the current ISO 8662 series of standards could not apply directly to this type of tool, there was a need to design and validate a test bench to evaluate the vibration emission values of jackleg drills, while taking into account the conditions specific to the operation of this type of tool. Methods A test bench including an energy absorber, was developed for testing jackleg drills based on the ISO 8662-3 standard 5. The energy absorber was bolted to a 3300 kg concrete block to ensure tool stability. A pictorial view of the device is given in Figure 1. For validation purposes, acceleration measurements at the handle of a conventional jackleg drill were taken simultaneously along the three axes (xh, yh and zh) in an underground rock drilling operation as well as on the test bench. The handle accelerations were measured for three different jackleg angles (13º, 28º and 43º) determined with respect to the floor. Moreover, each measurement was repeated at least three times to asses the data repeatability. [ ] Results As a preliminary validation of the test bench, Figure 2 provides a comparison of the frequency weighted rms acceleration spectrum measured along the zh-axis, for both underground drilling and operation on the test bench (28º jackleg angle in both cases). It is shown that the vibration measured on the handle of a jackleg drill operating on the test bench is representative of that recorded during typical rock drilling operations, despite the fact that some harmonics of the percussion frequencies are generated with a higher amplitude on the test bench. Table 1 provides

Jan 6, 2006

By Daniel G. DiCanio

This report describes a computer-based model for estimating the tangible costs of injuries and deaths from work-related accidents in underground coal mines. The study undertook to identify and quantify the elements of accident costs, including field visits to coal mines, insurance carriers, and public agencies. The mathematical models developed for each tangible element of accident cost are presented in Volume I -of the report. A listing of the computer programs which comprise the model and instructions for using the programs are presented in Volume II. Statistical distributions of mining family characteristics, data on 95 miners killed in underground accidents, and other basic data used to develop the model are presented in Volume III. Application of the model to a data base of 9,286 accidents which occured in underground bituminous coal mines during 1974 yielded a total of $56,900,000 in tangible costs to industry, mining families, and public agencies. Loss of income to the families of miners injured or killed in these accidents accounted for 47 percent of the total.

Jan 1, 1976

By John R. Bartels

Remote operation of continuous mining machines has enhanced the health and safety of underground miners in many respects; however, numerous fatal and non-fatal continuous miner struck-by accidents have occurred. In an effort to prevent these injuries, NIOSH researchers at Pittsburgh Research Laboratory studied the workplace relationships between continuous miner operators and various tramming tasks of the equipment using motion capture data, operator response times, and field of view data to evaluate the factors influencing operator-machine struck-by events (contact with a solid object) in a virtual mine environment. It is not feasible (nor ethical) to use human subjects to directly evaluate factors that precipitate such injuries. However, use of motion analysis data and digital human models can facilitate analysis of struck-by accident risk by allowing investigators to manipulate factors that influence injury. Factors included in this study included machine speed, direction of escape, the direction the operator was facing relative to the machine, work posture, distance from machine, and operator anthropometry. Close proximity to the machine, high machine tramming speeds, a right-facing orientation and operator positioning near the tail all resulted in high risk of being struck.

Jan 1, 2008

By Mark P. Meyer

This U.S. Bureau of Mines publication presents salient information in abstract form on 247 coal deposits in Alaska. Coverage includes currently producing deposits and deposits that appear to have commercial production potential. Data arc taken from coal properties identified by the U.S. Bureau of Mines minerals availability program and by a literature search. Infrastructural and institutional factors affecting coal development in Alaska are also discussed.

Jan 1, 1987

By R. R. Allen

Gieseler plastometer tests were performed on eight western coking coals at retort - immersion depths ranging from 2 to 3-3 /4 inches (measured to the center of the coal charge ) . Increased maximum fluidities were associated with greater retort - immersion depths , the most pronounced increases being observed on highly swelling coals when tested at 3-3 /4 inches . The maximum fluidity of one of these coals when tested at 3-3 /4 inches was 146 percent greater than that observed at 24 inches . Retort - immersion depth had no significant effect on the temperatures of initial softening , fusion , maximum fluidity , end of fusion , and solidification .

Jan 1, 1964

By Robert S. Becker

The results of a laboratory investigation of coal cutting mechanics and noise is presented. These experiments were performed using a linear cutting apparatus that operates over a broad cutting speed range. The influence of several coal cutting parameters on the noise, force, productivity, and specific energy associated with linear cuts is ascertained. Some basic theoretical aspects of coal cutting mechanics and noise generation are discussed, and the results of the laboratory experiments are used to Formulate analytical models of the coal cutting forces and noise. The analytical model For coal cutting noise is then generalized to account for the more important effects of rotary cutting. Based on the generalized model, an estimate of the sound pressure level at an operator's position is made for a typical continuous mining machine. It is concluded that by employing linear rather than rotary cuts, using deeper depths of cut, slower cutting speeds, and more efficient cutting tools, it is possible to reduce the level of coal cutting noise, as well as Provide benefits to other important areas of underground health and safety.

Jan 1, 1980

When the Organic Act of 1910 established the Bureau of Mines within the Department of the Interior, the Bureau's programs involved only health and safety research and, education, and fuels testing. As the Federal Government's primary agency for research in minerals, the Bureau has expanded its scientific and technological investigations to mining, processing mineral substances, eliminating occupational health and safety hazards in the mineral industries, economic development, and resource conservation. Today, Bureau activities cover a broad spectrum of programs for meeting the diverse (and sometimes conflicting) needs of mineral industries, government, and the public. In the 1960's, the Bureau initiated programs to resolve environmental problems associated with past mining and mineral processing. In the 1970's, the energy crisis raised the national consciousness concerning our limited supplies of domestic mineral and fuel resources. Dependence on foreign sources of raw materials critical to our national economy and competition from other countries for these world supplies stimulated the need to conserve and use with intelligence the Nation's minerals, metals, and fuels.1

Jan 1, 1977

By BUREAU OF MINES

Mercury has been used by mankind since prehistoric times. It has been, and is now, widely used in industry and medicine and has unique properties which make direct substitution difficult or impossible. At present its prin- cipal uses are for electrical apparatus, control instruments, electrolytic soda preparation, mildew-proofing paints, pesticides, and medical and dental preparations. Deposits of mercury are less common than those of other base and precious metals, but some of the deposits are very large and have been ample to meet the world's past demands. The price of mercury has had many sharp fluctua- tions, but in general, the limited number of producers has resulted in a more stable price structure than that of many other commodities. The United States has been one of the main producers of mercury, and from 1850 to 1961 produced 3,247,704 flasks. Yearly production since World War II has varied from 4,535 to 38,067 flasks. An estimate of domestic resources of mercury producible at various price ranges was prepared for each mercury mine by combining specific knowledge of mercury mineralization with estimates of potential, based on geologic informa- tion and past production history. The sum of the individual estimates for each price range is shown in a table. A parallel estimate of nationwide production potential was made from a study of past price and production relationships. These were analyzed by plotting yearly production figures against the previous year's price, expressed in dollars of constant purchasing power. An equation was fitted to the data by mathematical means and was used to extend the curve into areas of higher than historic prices. Potential production rates at various price levels were taken from this graph. The estimated yearly production rates were used to make an estimate of total potential based on the premise that produc- tion rates and reserves have a proportionate relationship.

Jul 1, 1964

Australia is tightening its rules governing mineral processing and the purchase of rural land by foreign investors" Rural land purchasers in the future will have to demonstrate to the Foreign Investment Review Board, the applicable governing body, that they will introduce new techniques or developments that will benefit Australia. In mineral processing, the criterion will be the availability of maximum opportunities for Australian equity capital. The changes are designed to discourage absentee landlords and speculators from abroad. A diamond field discovered several years ago in the northern section of Western Australia, known as the Kimberley region, is now thought to be one of the largest in the world, according to Conzinc Riotinto of Australia Ltd. (CRA). Figures released late in 1981 by CRA indicate that the main orebody of at least 100 million metric tons contains possibly 500 million carats of diamonds with a conservative market value of $8 billion. The diamond stones in the 100-acre deposit are about 10% gem-quality, 30% near gem, and 60% industrial. Initial production is expected to be about 17 million carats annually, which could be expanded to 25 million carats annually. World production of natural diamonds has been about 40 million carats per year from a reserve base of about 700 million carats.

Jan 1, 1982

By R. Farrar

Protective canopies for conventional electric face equipment, including shuttle cars, operating in low coal (less than 48 inches) were designed, fabricated, installed and evaluated on in-mine machines engaged in regular coal mining operations. This work was performed under contract to the U.S. Bureau of Mines, Pittsburgh Mining and Safety Research Center. The canopies will support a vertical load of 18,000 pounds and provide protection against both roof falls and contact with the mine rib. Canopy configurations were established based on human engineering studies, full scale canopy mockups, and in-mine observation and consultation with mine and equipment manufacturing personnel. Overall height of each canopy is hydraulically adjustable between a minimum of 32 inches and a maximum of 40 inches. Canopy tops are open framework, welded structures, covered with expanded metal mesh. Structural members are 1 3/4-inch or 2-inch square tubing of AISI 413ON and ASTM A500 material, respectively. The canopy tops are typically supported by an understructure and upright post arrangement that is either integrated into the current operator platform or attached to the machine frame. The four upright corner posts house the hydraulic actuators. Canopy tops are elevated horizontally. Canopies are welded or bolted to the existing machines. Installation is accomplished with a minimal amount of interface modifications. No major machine design changes are required. Canopies were trial installed and load tested at the manufacturer's facility prior to installation on the in-mine machines. Canopies were installed on a Joy 14BU10 Loader, 16RB-3AH Cutter, and two 21SC Shuttle Cars, and a Galis 300 Roof Drill and 460-S Face Drill. Canopy installations were evaluated in the Jewell Ridge Coal Company No. 12 and Big Creek Tiller Mines. Operational time accumulated on the installations during evaluation ranged from 1 week to 14 weeks of two-shift operation. All five canopy designs, manufacture, and test were successfully accomplished. The five canopies met all safety requirements. Three of the five canopies were deemed to be completely successful from an operator's point of view. That is, mine management as well as the machine operator found that the canopies did not impede the operation of the machines to function with the same efficiency as before the installation of the canopies. The loader canopy, in fact, appeared to have provided a mole efficient operation of the loader by providing added safety to the operator from rib contact thus allowing him to concentrate more fully on the loading function. Operational problems were encountered with the shuttle car and the roof drill. The shuttle car canopy obstructed visibility to an objectionable amount and the roof drill canopy impeded maneuverability of the machine, more than doubling the roof bolting time.

Jan 1, 2012

By authority of the Federal Coal-Mine Inspection Act of May 7, 1941, Public Law 49--77th Congress, H.R. 2082,2/ a Coal-Mine Inspection Division was established in the Health and Safety Branch of the Bureau of Mines. Funds totaling $729,000 for the operation of the division and for other incidental expenses were provided in an amendment to the Department of the Interior appropriation bill for the fiscal year 1942 (H.R. 4590). A small. percentage of these funds was made available on July 1, 1941, and a much greater proportion on October 1, 1941, to defray the expenses of the coal-mine inspection work and incidental activities for the remainder of the fiscal year 1942. The Coal-Mine Inspection Division is charged with administering the act and is required to compile, analyze, publish, and otherwise make available for public inspection the information obtained under it and to transmit such information to the Director of the Census. The act requires also that the information obtained be reported to Congress, with such findings and comments thereon and such recommendations for legislative action as may be deemed proper.

Jan 1, 1943

By Robert S. Hedin

Passive methods of treating mine water use chemical and biological processes that decrease metal concentrations and neutralize acidity. Compared with conventional chemical treatment, passive methods generally require more land area, but use less costly reagents and require less operational attention and maintenance. Currently, three types of passive technologies exist: aerobic wetlands, organic substrate wetlands, and anoxic limestone drains. Aerobic wetlands promote mixed oxidation and hydrolysis reactions, and are most effective when the raw mine water is net alkaline. Organic substrate wetlands promote anaerobic bacterial activity that results in the precipitation of metal sulfides and the generation of bicarbonate alkalinity. Anoxic limestone drains generate bicarbonate alkalinity and can be useful for the pretreatment of mine water before it flows into a wetland. Rates of metal and acidity removal for passive systems have been developed empirically by the U.S. Bureau of Mines. Aerobic wetlands remove Fe and Mn from alkaline water at rates of 10-20 and 0.5- 1.0 g. m-2? d-1, respectively. Wetlands with a composted organic substrate remove acidity from mine water at rates of 3-9 g. m-2? d-1?. A model for the design and sizing of passive treatment systems is presented in this report.

Jan 1, 1994

By Martin J. Gavin

During the recent study of lubricating oils carried on in the San Francisco laboratory of the United States Bureau of Mines, it became desirable to distill the oils used in the experimental work at pressures as low as 10 millimeters (mercury column) absolute. In the effort to Overcome difficulties and eliminate sources of error, certain changes were made in the apparatus for vacuum distillation used by the Bureau of Mines for crude petroleum.4 These changes were described in R.I. 2819, issued in July, 1927. Subsequent to the publication of R.I. 2819 several other changes have been made, and the present form of the apparatus for vacuum distillation of lubricating oils is described in this revision of R.I. 2819. These changes were found to give more accurate checks on duplicate distillations. The major part of the credit for the laboratory work which developed the changes in the apparatus and method revised herein is due to Boyd Guthrie, assistant petroleum chemist, and R. V. Higgins, junior chemist, o the San Francisco laboratory, United States Bureau of Mines. DESCRIPTION OF APPARATUS The distilling flask employed is essentially the Hempel flask as used by the United States Bureau of Mines for the analytical distillation of petroleum.5 he complete apparatus is shown in Figure 1. The fractionating column and exposed portion of the flask is wrapped with 4 inch asbestos rope and then surrounded by a cylindrical hood of 1/8 inch pliable asbestos sheet with a narrow air space between the wrapping and the cylindrical hood. This was found necessary to prevent any radiation or convection heat losses from the column, and resulted in obtaining a more even and constant fractionation by eliminating any dephlegmating action caused by temperature changes around the column.

Jan 1, 1930

This report describes the new Bureau of Mines Core Repository System (CORES) and presents the methods for selecting, processing, and storing physical samples and descriptive data for future reference by earth scientists. The system preserves splits of chip samples and longitudinally sliced segments of core. A records retrieval system provides for storage of data on microfilm and magnetic tapes and uses the keysort parameters of location and commodity for the identification of data.

Jan 1, 1978

By Danqing Xu, A. W. Khair

"This paper presents a laboratory simulation of regrinding and resulting dust generation. An Automated Rotary Coal Cutting Simulator (ARCCS) was modified to conduct regrinding experiment. In order to estimate the effects of coal properties and operating parameters on regrinding and dust generation, an orthogonal fractional factorial experimental design was implemented in regrinding experiment. Marple personal cascade impactors, Series 290, were used to measure dust concentration during experiment. Three types of coal seams, namely, Waynesburg, Pittsburgh, and Lower Kittanning, were used to represent different coal properties. Experimental results and complete parametric analysis were presented.In a rotary cutting system, all the broken coal and part of the remaining coal from previous cutting cycles must be transported through part or entire circumference of the cutting drum. This transportation of already recovered coal through the cutting zone of rotary head makes it a rotary grinder. Some of the coal particles will be subjected to secondary fragmentation or regrinding in the process. The potential effect on dust generation by regrinding is significant because the cutting head utilizes kinetic energy to comminute recov¬ered coal material. The moving bits and bit blocks on the cutting head impact coal particles and transfer some of their kinetic energy to the particles. After obtaining kinetic energy, coal particles are free to impact one another and they also impact the coal seam or cutting head. During impact, high impact force and high internal stress concentration are created in the particles. Kinetic energy is transformed into strain energy. When stored strain energy exceeds allowable strain energy, the particles will break. A great amount of respirable dust will be generated due to impact failure. In reality, regrinding occurs at the same time as primary cutting. The particles to be ground are the result of primary cutting. Both primary cutting and regrinding produce dust. Therefore, it is impossible to separate regrinding from primary cutting. In order to study respirable dust generation by regrinding and analyze the influencing parameters, a laboratory approach was adopted. In this approach, it is possible to study the regrinding separating from primary cutting."

Mar 1, 1992

By David Bendersky

This report covers the activities of a feasibility study of fiber optics technology fur use in mines. The objective of the study was to evaluate, both technically and cost-wise, the possible use of fiber optic technology for underground mine communication and monitoring systems. The first phase of the study was devoted to the collection of information on the present underground mine communication systems and monitoring techniques, and the status of applicable fiber optic technology. In the second ph se of the study, a communication and monitoring system for a hypothetical underground coal mine was designed and the costs estimated. The significant findings and conclusions are presented.

Jan 1, 1982

By Mayer G. Hansen

A series of papers dealing with diamond drilling practices, compiled in accordance with an outline prepared by engineers of the United States Bureau of Mines, is to be published as information circulars by the bureau. This paper, the first of the series, describes the general practice at the United Verde mine during the last ten years; specific instances cited in the paper refer to 1930, the last year of full operation. The United Verde copper mine is located at the town of Jerome, Yavapai County, north central Arizona.

Jan 1, 1933

By Frank E. Cash

Although during the past 10 years Alabama has attained an enviable position by its coal-mine accident experience and, like most of the other coal-mining States, has made progress in the safer operation of coal mines, there is still room for improvement, which can be realized only by still greater efforts on the part of employees and employers. From 1993, when accidents were first recorded by the Alabama State Mine Inspection Department, to 1934, inclusive, 3,451 men lost their lives in the production of 569,722,676 tons of coal. The primary purpose of this report is to bring to the attention of the mining industry in Alabama end elsewhere statistics of fatal accidents for 1931-34, with the hope that a study of the causes may lead to reduction of similar accidents in the future.

Jan 1, 1936

By Gregory P. Cole, Peter G. Kovalchika, Rudy J. Matetic, Adam K. Smith

Previous studies conducted by the National Institute for Occupational Safety and Health (NIOSH) have shown that approximately 90% of coal miners and 49% of metal/nonmetal miners had a hearing impairment by age 501. Mine workers are exposed to additional noise levels underground due to the reflection of machine generated noise that would otherwise dissipate in an above ground setting. Determining the sound absorption coefficients is essential in modeling the sound field in an underground mining environment. Sound absorption is a measure of the amount of acoustic energy that strikes a surface and is absorbed, rather than reflected. The acoustic environment that mining machines operate in is a critical factor affecting the sound pressure level exposure for mining machine operators. Impedance tube testing is an inappropriate method for determining underground absorption coefficients due to the brittle composition of some of the materials such as coal and slate. Classic absorption coefficient estimation using T60 measurements will not work well in an underground environment because the theory assumes: a finite room, a diffuse field, and relatively uniform absorption. None of these assumptions are true in an open-ended mine entry. This paper will present a method using a ray-tracing technique to determine absorption coefficients for underground mines. Absorption coefficients are determined and presented for octave bands from 63 Hz to 8 kHz. The absorption coefficients will be essential for determining and predicting potential overexposure to machine operators in different mine environments.