Search Documents

By Kathleen J. D?Amico

This summary appears in Minerals Year- book volumes I-II, and III, which cover mineral production in the United States, its island possessions, the Canal Zone, and the Commonwealth of Puerto Rico, as well as the principal minerals imported into and exported from the United States. The sections of this chapter and the area chapters in volume III contain further details on production. A summary table comparing world and U.S. mineral production also is included. Mineral production may be measured at any of several stages of extraction and processing. The stage of measurement used in the chapter is normally what is termed "mine output." It usually refers to minerals in the form in which they are first extracted from the ground, but customarily includes for some minerals the product of auxiliary processing operations at or near mines.

Jan 1, 1970

By W. H. Ode

Low-temperature distillation tests at 200°, 350°, and 500° C. were made on a subbituminous coal from Boulder County, Colo., and a subbituminous coal from Weld County, Colo., in connection with a survey of carbonizing properties of American coals4/ and. investigations of their chemical and physical properties.5/ The coal represented by the sample from weld County was reported to give off combustible volatile matter at unusually low temperatures when placed on a fuel bed. The yields of tar and oil and the composition of the gas from this coal, as obtained in the distillation tests, did not confirm this report. These yields and the gas composition of the Weld County coal differed but little from those obtained from the coal from Boulder County. Both coals yielded tar and gas in amounts considered to be normal for coals of their rank.

Jan 1, 1937

By W. H. Ode

Low-temperature distillation tests at 200°, 350°, and 500° C. were made on a subbituminous coal from Boulder County, Colo., and a subbituminous coal from Weld County, Colo., in connection with a survey of carbonizing properties of American coals and investigations of their chemical and physical properties. The coal represented by the sample from Weld County was reported to give off combustible volatile matter at unusually low temperatures When placed on a fuel bed. The yields of tar and oil and the composition of the gas from this coal, as obtained in the distillation tests, did not confirm this report. These yields and the gas composition of the Weld. County coal differed but little from those obtained from the coal from Boulder County. Both coals yielded tar and gas in amounts considered to be normal for coals of their rank.

Jan 1, 1937

By John H. Soulé

"INTRODUCTION The Peerless mine was examined by W. R. Storms, an engineer of the Bureau of Mines, on June 2, 1944, in conjunction with a mineral survey of the adjoining For Bayard Military Reservation. Storms again studied the mine on January 13; 15 and 16, 1945, to determine the possibilities of finding new ore reserves to replace these depleted by mining. A project to explore the Peer-less vein at depths below and to the south of the principal mine workings was proposed. Special attention was given to the possibility of exploring favorable beds in the Magdalena and Lake Valley limestones at points near the Peerless fault.The proposed project was approve and exploratory work started on January 2, 1946, and was completed on June 5, 1946. The mine was not in operation during the project, and all equipment had been removed."

Apr 1, 1947

By Howard E. Parkinson, John N. Murphy

Abstract-Underground mines are typically extensive labyrinths that employ many people working over an area of many square miles; exten¬sive analysis of mine-communications systems has identified specific problem areas, in particular the excessive times required to locate key personnel underground, the inadequacy of existing phone systems in terms of capacity and privacy, and the inability to communicate with men on the move with wireless communications, as is taken for granted on the surface. A review is presented of the existing systems, the prob¬lem definition, and the various approaches that have been or are being investigated to solve these problems. Manuscript received June 8, 1977; revised August 28, 1977. The authors are with the Industrial Hazards and Communications group, Pittsburgh Mining and Safety Research Center, Bureau of Mines, U.S. Department of the Interior, Pittsburgh, PA 15213.

Aug 28, 1977

By A. T. Iannacchione, D. G. Puglio

This Bureau of Mines study covers 25 underground mines that were active in the Upper and Lower Freeport and Lower Kittanning coalbeds in 1976. The coal ranges from low to medium volatile in rank; its primary use is for steam generation. Seven mines emit more than 100,000 cfd of methane gas; those mines are the deepest and largest producers. The methane gas content of three core samples of the Lower Kittanning coalbed was estimated by the direct method. A sample from a depth of 320 feet contained 0.5 cu cm of gas per gram, at 620 feet there was 0.8 cu cm of gas per gram, and at 1,060 feet there was 11 cu cm of gas per gram. These results suggest that methane control problems will be encountered in the future as deeper coal is mined.

Jan 1, 1979

By Joseph J. Wallace

1. The Pocahontas No. 3 and Pocahontas No. 6 ere the two most important beds in Mercer County from the standpoint of present production and recoverable reserves. 2. Known measured and indicated reserves in all beds, based on a minimum thickness of 14 inches and 1,800 tons per acre-foot of coal in place, are estimated at 188 million short tons as of January l, 1953. Of this total, 80 million short tons are in beds 28 inches and more thick. Areas in each bed were omitted from the estimate because available data relative to the bed characteristics are too meager to make an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimated reserves.

Jan 1, 1954

By D. G. Puglio

This Bureau of Mines study covers 25 underground mines that were active in the Upper and Lower Freeport and Lower Kittanning coalbeds in 1976. The coal ranges from low to medium volatile in rank; its primary use is for steam generation. Seven mines emit more than 100,000 cfd of methane gas; those mines are the deepest and largest producers. The methane gas content of three core samples of the Lower Kittanning coalbed was estimated by the direct method. A sample from a depth of 320 feet contained 0.5 cu cm of gas per gram, at 620 feet there was 0.8 cu cm of gas per gram, and at 1,060 feet there was 11 cu cm of gas per gram. These results suggest that methane control problems will be encountered in the future as deeper coal is mined.

Jan 1, 1979

By W. H. Young

PRODUCTION of bituminous coal and lignite increased substantially in 1963 compared with 1962 figures. The major items of production, consumption, exports, and productivity increased. However, certain key items declined. For the fourth year there was no upward trend in mechanization; the percentage of total tonnage mechanically loaded remained the same as in the 3 previous years and the percentage of total tonnage mechanically cleaned was smaller than in the previous year. Furthermore, the percentage of total production mined by stripping and by augers increased. Most significant was the continued decline in average value and employment. Production.-The output of bituminous coal and lignite in the United States in 1963--459 million tons-was 9 percent greater than the 422 million tons produced in 1962. Production was greater in 1963, largely because of expanded consumption by the electric utilities and an increase in exports.

Jan 1, 1964

By David E. Van Dillen

This volume is a task-by-task review of work performed in modernizing the BMINES finite element code. Much of the discussion is accomplished by cross reference to the user?s guide, which is Volume I of this two-volume report. The computer program described in this report provides for the static, three-dimensional, linear and nonlinear analysis of structural and geologic systems by the finite element method. The nonlinear material properties currently available in the code include isotropic, anisotropic, variable modulus, plastic, viscoelastic, and viscoplastic. Load application capabilities include gravity loading, surface tractions, and initial stresses. The element library includes rods, beams, plane and axisymmetric quadrilateral elements, three-dimensional brick elements, thick shell elements, and plane, axisymmetric, and three-dimensional joint elements. Special features include the ability to simulate excavation and construction sequences by means of element activity. An automatic mesh generator is included in order to simplify input preparation.

Jan 1, 1981

? A roof bolter reaches for a lever while guiding the drill with his other hand. Since he's watching the drill and many of the controls look and feel alike, he hits the wrong control and crushes his hand. ? Six hours into the night shift, an ore truck driver dozes off. The truck plows over the berm and down into the pit. ? Fleeing a afire, a face crew sees smoke in the intake entry. Assuming the fire is ahead, they cross over to another entry, but soon encounter even worse smoke. These very different accidents have at least one factor in common: the human factor. The actions, decisions, thoughts, or perceptions of one or more humans contributed to the accident. These are just a few examples of safety problems researched by the Human Factors Group of the Pittsburgh Research Center, U.S. Department of Energy.

Jan 1, 1998

By E. William Rossi, Sean Gallagher, Richard L. Unger

The purpose of this study was to examine the lifting capacity of low-seam coal miners in four restricted work postures (roof heights of 36", 40", 44", and 48"), investigate the associated metabolic costs, and to examine electromyographic (EMG) data from eight trunk muscles during the lifting procedure. Subjects were thirteen underground miners accustomed to handling materials in restricted work postures. Each subject performed two twenty-minute periods of asymnetric lifting in each of four postures during the day of testing. The. frequency of lifting was 10 lifts per minute. A specially designed lifting box incorporated microswitches in one handle of the box and another in the bottom of the box, in order to examine the trunk muscle function at specific points during the lfting cycle. The data collected will be used by the Bureau of Mines to make recommendations for lifting materials in low-seam coal mines.

By Margaret R. Egan

In an underground mine fire, a toxic mixture of combustion product gases and particulate matter is transported by the ventilating system endangering everyone downstream. To determine the magnitude of the problem that these toxic combustion products pose, the U.S. Bureau of Mines is investigating the combustion products of typical materials found in underground mines. The total toxicity of the combustion products depends upon the evolving gas species and particulate matter, the amount of material involved, and the ventilation rate. In a simulated mine environment, the products from smoldering poly- vinyl chloride (PVC) brattice and conveyor belting were analyzed for gas concentrations and smoke characteristics. The primary toxic gases are hydrogen chloride (HC1) and carbon monoxide (CO). Smoldering conveyor belts are more detectable than smoldering PVC brattice cloths. These results, combined with previous analyses, are used to estimate relative toxicities, product levels, and detect-ability of smoldering mine combustibles.

Jan 1, 1992

By A. J. Miscoe, W. M. McKewan

A unique machine for inducing bending fatigue in wire ropes was built at the U.S. Bureau of Mimes' Pittsburgh Research Center. This machine can produce nine levels of degradation through repetitive cycling of long samples of wire ropes of the types used in the mining industry. This report provides an analysis of the results of the first wire rope to be fatigued on this machine. These results have indicated that as a wire rope accumulates bending cycles, its strength first decreases because of wear and then in- creases due to cold working of the wires. As the amount of cold working increases, more and more of the embrittled wires break and the strength of the rope decreases rapidly. In this test, application of several of the regulatory retirement criteria to various sections of the rope suggests that there may be some inconsistency among them.

Jan 1, 1993

By M. J. Friedel, D. F. Scott, T. J. Williams

In an effort aimed at monitoring mining-induced stress changes that may influence ground failure, the US Bureau of Mines conducted a series of active 3-D seismic tomographic surveys at the Homestake (Lead, South Dakota) and Lucky Friday (Mullan, Idaho) mines. Existing rock bolts were used to mount geophones and as strike points for introducing seismic energy using a 3.6 kg sledge hammer. Travel time measurements were recorded spanning up to 160 m between drifts at several levels. The tomographic uncertainty was minimized by computing iso-velocity surfaces of constant probability based on statistics from multiple reconstructions and a threshold criteria. Periodic imaging using tomographic velocity surfaces demonstrated that temporal and spatial changes in the local stress field occurred in response to ground failure and stope advancement at a gold and silver mine, respectively. Keywords: Temporal imaging; Mine-induced stress; Seismic tomography; Geophysics

Sep 9, 1996

By Dana Reinke, William Wiehagen, Launa Mallett, Charles Vaught, Kathleen M. Kowalski, Michael J. Brnich, Lynn Rethi, Lisa Steiner

Safety and health professionals from all sectors of industry recognize that training is a critical element of an effective safety and health program. A major concern in the mining industry today is how to train the present aging workforce plus the expected influx of new and less experienced miners and mine operators as the cohort of older workers retire. This paper defines the problem, offers a model to structure the inquiry, and presents the key issues a multi-disciplinary team of NIOSH researchers identified, based on an extensive review of the current literature in relevant areas. Issues include differences between cohorts, such as the newer workers (Generation M), and present workers (Boomers) with respect to their physical, social, psychological, and cultural characteristics, their learning styles and work expectations. Specific issues for an aging workforce are discussed. Some preliminary recommendations are offered on the type of training needed.

By Tye J. Lasich

This project involved modeling rock masses with varying Rock Mass Rating (RMR) values to determine the degree of instability that develops around an underground opening as a function of RMR. The modeling was performed using Itasca?s UDEC distinct element software, which allows explicit modeling of blocks of rock and how they interact with each other. The analyses included three different orientations of the joint sets, four different joint spacings and three different values of joint strength, which combine for a total of 36 different combinations of model parameters. Two different modes of behavior were observed: local failure of area immediately surrounding the roof and sides of the opening, and deep-seated failure extending a large distance beyond the opening. Quantification of the size of the unstable area that developed provides numerical validation of empirical guidelines used in design of ground support and instrumented monitoring systems.

Jan 1, 2005

By Dara Stock, Fred Turin, Kim Cornelius, Lisa Steiner

Growing concern from labor unions, regulatory agencies, and industry about the safety of a prevalent underground coal mining method which utilizes remote control has prompted human factors field evaluation of mining activities. Remote control operations were implemented with little consideration given to human-system interactions. Ideally, collecting and analyzing information prior to implementing new technology would have helped to address potential problems. One such problem that operators and other mine personnel are faced with is the question of where they should safely position themselves to avoid injury while remotely operating machinery. To determine work methods employed by machine operators before and after implementation of the new method, work sampling techniques have been used to provide data about positioning of face crew members at different points in the mining cycle. This data provides information for optimal positioning, leading to safer operating procedures and identifying training shortfalls.

By Fred Biggs, Walter Utt, Richard Miller

Powered haulage has been, and continues to be, a major source of severe accidents and fatalities at metal/nonmetal surface mines. Between 1986 and 1997, truck drivers accounted for63% of the lost-time injuries in surface haulage. This project was undertaken to reduce the number and severity of lost-time injuries among operators of these trucks. Work involved measuring shock acceleration at a western surface mine during representative work cycles on two types of trucks and collecting data from cab floors using a triaxial accelerometer and from operator seats using a seat pad accelerometer. NIOSH researchers also used the mine’s GPS systems to locate shock events on a mine map in real time. Shock tests were also run at Caterpillar, Inc.’s, proving grounds in Green Valley, AZ, to determine the magnitude of shocks resulting from controlled rock drops onto the bed of a haulage truck.

By C. I. Pierce

The Bureau of Mines conducted laboratory tests to determine if ultrasonic energy could reduce either the residual water or oil content of petroleum reservoir-rock samples from Appalachian area oilfields. Brine-saturated core samples were flooded with oil to residual brine saturation and subjected to 20 kilocycles per second ultrasonic energy. Then they were flooded with brine to residual oil saturation and again subjected to ultrasonic energy. Additional water displaced as a result of the application of ultrasonic energy to the flow system ranged from 0 to 4.3 percent of the original brine and averaged 1.9 percent. The increase in oil recovery as a result of the ultrasonic energy ranged from 0 to 9.0 percent of the original oil and averaged 3.1 percent. On the basis of the tests, it appears that 20-kcps acoustic waves would not have field application for oil recovery.

Jan 1, 1968