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By Klaus L. Cappel

In 1972, the Bureau of Mines of the U. S. Department of the Interior commissioned the development and design of a Simulator for research and testing of mine roof supports used in long-wall mining. The purpose of the Simulator is to reproduce forces and displacements of a section of a mine roof in contact with one or more supports. This report is an account of the design process that resulted in the final configuration of the Simulator presented here. It includes discussions of engineering considerations that led to major changes in important details of the Simulator. These changes, however, did not substantially alter the basic design originally proposed, except for the elimination of certain originally-specified features that were adjudged as insufficiently cost-effective by both the Bureau of Mines and the design agent at an intermediate stage of the design.

Jan 1, 1974

By Forrest T. Moyer

In 1969, the number of fatal injuries in the coal mining industry was lower than in any previous year and the number of nonfatal injuries was lower than in any preceding year except 1968. Fatal injuries in 1969 totaled 203 with frequency rates of 0.85 per million man-hours of worktime and 0.36 per million tons of coal These rates were new annual lows. Nonfatal injuries totaled 9,917 with frequency rates of 41.76 per million man-hours and 17.42 per million tons. The severity rate for fatal and nonfatal injuries combined was 7,359 days lost or charged per million man-hours. The average severity was 173 days lost or charged per injury. These statistics represent the injury experience of an average of 133,302 employees per day working an average of 225 days in 5,955 coal mines for a total of 237-5 million man-hours worked and a coal output of 565 2 million tons

Jan 1, 1973

The purpose of this study was to examine the problems of underground coal mining in the United States, and to develop recommendations for an integrated Research and Development Program aimed at resolving these problems. Specific objectives of the study were as follows: ? To identify the existing inadequacies that have adverse effect on Health, Safety, External Environment, and Productivity. ? To identify opportunities for technological advance s to correct these inadequacies. ? To develop an integrated Research and Development Program designed to accomplish the advances identified. Many of the recommended tasks are dearly long range; this is especially true of those for study of future mining systems. However, funding recommendations in this Report are presented for a 5 -year period, since the developments accomplished during this period will undoubtedly be a factor in the formulation of the follow on tasks. Where applicable, the recommended Research and :Development could include development and test of pilot model equipment.

Jan 1, 1970

By Rudolf E. Greuer

This report contains a theoretical study on the usefulness of fighting mine fires with inert gases. Four introductory chapters review the role of fires in the mining industry; the conventional fire fighting techniques, the influence of inert gases on the burning of gases and solids, and the well established inert gas fire extinguishing systems for buildings and machinery. A large chapter describes the use which inert gas has found so far for fighting mine fires in major mining countries. More applications have occurred than generally expected and the inert gas method has in the last years become routine in Czechoslovakia and the USSR. This chapter is based on an evaluation of the extensive literature as well as on personal information obtained from leading experts.

Jan 1, 2012

By K. B. Bengtson

This task report provides the process technology, preliminary design, capital and operating costs for a 25 TPD pilot plant to produce cell-grade alumina using a clay/hydrochloric acid extraction - HCI gas induced crystallization process. The report consists of six volumes: I - Process Technology and Costs; II and III - Equipment Lists, Specifications and Quotations; IV and V - General Specifications; VI - Drawings. The process was selected by the Bureau of Mines as the more promising method to produce cell-grade alumina from clay based on the results of the two previous task reports under this contract: Task I - Comparison of Six Processes (alunite, anorthosite-lime sinter, clay/sulfurous acid, clay/nitric acid, clay/hydrochloric acid evaporative and gas-induced crystallization) and Task 2 - Comparison of Two Processes (clay/nitric acid and clay/hydrochloric acid - gas induced (crystallization). The pilot plant process utilizes a unique dual crystallization process to produce aluminum-chloride-hexahydrate crystals having sufficient purity when decomposed to meet stringent alumina product specifications. The size of the 25 TPD pilot plant has been selected to permit scale-up to commercial size plants of equipment, technical and economic parameters. The capital cost estimate for the pilot plant, exclusive of fee and escalation, for a southeastern U.S. location is $52,311,000 expressed in 1979 dollars. The total time required to construct the pilot plant including engineering and procurement is 32 months. The operating cost to produce the estimated 9,000 tons of alumina required for testing in Hall cells is $40,91[0],190 expressed in 1979 dollars.

Jan 1, 1979

By Forrest T. Moyer

The safety record of the coal-mining industry, both anthracite and bituminous, in 1966 was improved over that of 1965 in all general measures of injury experience. The improvement was more pronounced in the anthracite industry. The total of 10,679 disabling work injuries comprised 233 fatal and 10,466 nonfatal injuries, 26 and 692 fewer, respectively, than in 1965. The number of fatalities in 1966 was the lowest annual total since complete records were started in 1910. Similarly, the number of nonfatal injuries in 1966 was lower than in any year since 1930 when such data were first collected.

Jan 1, 1969

By David A. Summers

Coal is increasingly viewed as one of the major fuel resources of this country for the remainder of this century. The need to extract a greater percentage of the coal in a given seam, together with advantages of improved safety, indicates that longwall mining will become more widely used within this time frame. A novel method of mining coal on a longwall face, utilizing high pressure water jets, is herein described. The mining machine proposed will exploit the stress conditions which exist on a longwall panel in order to achieve the required productivity while at the same time reducing respirable dust and methane ignition hazards. The water jets will excavate only the boundary of the extracted seam section, and thus the energy requirement of the machine will be minimized. The action of the machine is similar to that of an existing coal plow, except in that the wedge teeth of the plow are replaced by oscillating high pressure water jets. The machine can, therefore, cut to the depth and at the speed of existing shearer units at equivalent power levels. The removal of impact stresses from the machine will reduce downtime required for maintenance and replacement of picks and lower the load on the haulage motor of the system. The ability of the machine to increase the depth of cut without an increase in horsepower will further improve productivity when transportation systems to remove the greater production are in operation.

Jan 1, 1974

By A. Baldwin

This report describes the engineering feasibility and economic advantages of a unique new mining machine using cutting bits that take a constant-depth linear cut in the coal face. The studies show that this innovative new cutting concept, being developed by the Bureau of Mines, can be designed into the basic continuous mining machine. The resulting miner would be attractive to mine owners because coal could be mined with minimum generation of airborne respirable dust, substantial increases in productivity, and elimination of methane ignition due to cutting.

Jan 1, 1977

By Boyd Wise

A jet pump injector was developed and successfully tested, thereby demonstrating the feasibility of a jet injector for introducing coarse coal into an operating slurry face haulage system: In Phase I a variety of injection concepts were evaluated, and the jet pump was identified as best, due to its simplicity, compactness and performance potential. In Phase IIA subscale jet pump injector tests were conducted, and a computer model of a jet pump injector was developed whose performance predictions correlated well with subscale test results. In Phase IIB various system configurations were defined for integrating a jet pump injector into a fully operational underground coarse slurry face haulage system, further highlighting the feasibility and practicality of such a system. In Phase III a full-scale mobile haulage vehicle embodying a jet pump injector and coal sizing equipment was detail designed into a practical vehicle with attractive performance characteristics. More importantly, fully operational full scale jet pump injector -and feeder/breaker subassemblies were tested and proven successful in their ability to down-size coal to 3" in all 3 dimensions and to consistantly provide slurry of 4217 weight concentration at 6.4 TPM throughput under a wide range of operating conditions including zero to maximum feed rate within 5 seconds.

Jan 1, 1985

By E. H. Burroughs

Persons interested in th_e study of petroleum and allied substances have long felt the need of a bibliographic index to the literature. This bibliography, which is intended to be the first elf a yearly series, has been compiled by the petroleum division of the Bureau of Mines with a view to satisfying this need. The references include only the more noteworthy writings that appeared during the year 191.5 in both ·the United States and foreign countries. Only patents plainly applicable to the industries in point have been included, although, of course, a close scrutiny of the great volume of patent literature might reveal many other patents of possible value. The references are arranged according to the subject classification on pages 3 to 11. This classification, which is to be followed in the succeeding bibliographies of this series, is offered as a guide for further study and classification of the pertinent literature.

Jan 1, 1918

By Gordon T. Austin

The combined production value of natural abrasives, which consist of tripoli, special silica stone, garnet, staurolite, and emery, increased in 1987. The increase was, in certain cases, because the materials were used in nonabrasive applications, such as the increased use of tripoli as a filler and special silica stone material as a special-purpose crushed stone. The increased use of garnet as a blasting media accounts for most of its growth. Production and sales of garnet were at a record-high level in 1987. [ ]

Jan 1, 1989

By Norman L. Wimmler

Active placer mining in Alaska began near Juneau in 1880, but the first gold rush did not start until 1896; then the discovery of the Klondike brought gold seekers from all parts of the world. A few of the newcomers were experienced miners, but the majority knew nothing whatever of placer mining. Even those who were placer miners of much experience found entirely new conditions, notably frozen ground, that presented many difficult problems. As a result, numerous methods of mining and of thawing frozen ground were tried. From these trials the practice described in this bulletin has been developed. All known placer fields in Alaska have been mined to some extent, and some have been virtually exhausted. In most districts, however, there remain large quantities of low-grade gravel and also some small isolated areas of comparatively rich gravels which could not be successfully mined because of adverse physical conditions. These districts are now the scene of most placer mining, including dredging, hydraulicking, drifting, mechanical methods of open-cut mining, and ground sluicing (or booming) followed by " shoveling-in."

Jan 1, 1927

By Joel N. Van Sant

THIS REPORT describes the occurrence, mining, and use of refractory clay in Colorado within Region III of the Federal Bureau of Mines, which includes the States of North arid South Dakota, Nebraska, Wyoming, Colorado, Utah, New Mexico, and Arizona. Field work by the Bureau of Mines, United States Department of the Interior, included examination of active and abandoned refractory-clay mines as well as a reconnaissance survey and sampling of numerous clay-bearing formations exposed in Colorado. Information from the survey and the sampling will help guide private industry in its search for virgin sources of refractory clay. Library research of published and unpublished reports from various Federal, State, and private sources was conducted during the early phase of the investigation. Most of the refractory clay mined in the Denver-Golden district of Colorado is not used for refractory purposes but is blended with other clays in the manufacture of structural clay products. The predominantly flint-clay de-posits in the Pueblo and Fremont County districts are mined and utilized chiefly in fabricating refractory products.

Jan 1, 1959

By David E. Van Dillen

The computer program described in this user's guide provides for the static, three-dimensional, linear and nonlinear analysis of structural and geological systems by the finite element method. The guide describes the capabilities and general features of the program and shows how input is prepared. A number of recent advances in finite element theory and computer technology are incorporated in the program. Nonlinear material properties are provided for, including isotropic, anisotropic, and time-dependent material properties, gravity loading, simulation of a sequence of excavation or construction, and a slip or joint element. The finite elements include beam, rod, axisymmetric and plane quadrilateral, hexahedron, thick shell, axisymmetric and plane joint, and a three-dimensional joint. The program also has an automatic mesh generator to minimize user input preparation for continuum finite element meshes.

Jan 1, 1981

By Wilbur I. Duvall

In a review of so 40 papers on damage to residential structures resulting from blasting, only 3 were found that present data on the observed amplitude and frequency of the vibration levels produced by blasting together with an observed degree of damage to a residential structure. The data from these three reports have been analyzed statistically to determine if one of the quantities, displacement, velocity, or acceleration, is more reliable than the others for estimating the degree of damage to a residential structure. From this analysis the conclusion is drawn that a given degree of damage to a structure is most closely related to the magnitude of the particle velocity of the wave motion passing thru the earth at the structure location. On the average, only minor damage it observed for peak particle velocities of 5.4 inches per second, and major damage is observed for peak particle velocities of 7.6 inches per second. When the spread of the data is taken into consideration, the following statement can be made: Wave motions that have a peak particle velocity in excess of 2 inches per second have a fair probability of producing some damage to structures, whereas wave motions that have a peak velocity less than 2 inches per second have a very low probability of causing any damage. Therefore, the recommendation is made that vibration levels in the vicinity of residential structures should be maintained below a peat particle velocity of 2 inches per second. The above criterion for safe blasting is considered to hold over a wide variety of soil and rock conditions because the original data were obtained for a wide range of soil and rock conditions and on various types of residential structures. INTRODUCTION Ever since explosives were discovered and developed for mining purposes, there has existed the problem of what effects the air and ground vibrations resulting from blasting have on structures of various types. This problem is

Jan 1, 1962

By R. H. Church, William E. Webb, Walter E. Pittman, James R. Boyle

As part of the Bureau of Mines health and safety research program, a short-range locator system, capable of locating miners who have become trapped following a mine accident, has been devised, The system consists of a lightweight, low-power radio transmitter incorporated into a miner's cap lamp battery and a directional receiver carried by rescuers. Prototype transmitters have been constructed, and the propagation of their signals has been investigated, The detectability of the signal in underground coal mines has also been investigated, This research indicates that a short-range location system would serve as an economical and practical means of locating miners from within the mine following an accident,

Jan 1, 1984

By Charles E. Semler

The possible utility of selected compositions in the systems SrO-ZrO2-MgO and SrO-ZrO2-Dolomite for commercial refractory products was confirmed in this study. Specifically the compositions of interest are located in the sub-systems SrZrO3-ZrO2-MgO and SrZrO3-ZrO2-Dolomite. Both sub-systems have regions that are not affected by hydration, but the sub-system SrZrO3-ZrO2-MgO has a larger candidate compositional region. Solid state phase relations were determined for the subject systems over the temperature range 1600°C to 1300°C, with compatibility diagrams presented for each. The systems appear to show good refractory character with no apparent low melting compositions. As the compositions of commercial interest lie mostly in the higher ZrO2 portion of each system, information is presented regarding the firing treatment required to develop stabilized cubic ZrO2. A list of suggestions for further study of these systems, to further delineate the characteristics required for possible commercial utilization, is presented.

Jan 1, 1982

By S. R. Zimmerley

[In the course of a flotation investi~ntion, a siliceous gold ore was ground ir, R 'ball mill to ~inils 300-mesh. It mas found that the small mount of zlus 300-~esh mnterial had a go12 assw approximately twice that of the oricinal ors, md thst this oversize ~roduct also contained much abra?.ed iron. >!oreover, the gold assay of the abraded iron, which was separated ma~etic-dl:;, wno ei::ht tiaes tkat of the ore. These facts sug,~estsd th~t sone r3laticnshin existed between the abnormally high .gold content and the preseace of abrade4 iron. It was ciecided, therefore, to investl~ate furtkor ths acsoclation of the ;old nith the iron abraded from the balls durir-g grincing. As a nrelininary ex?rr>hent, a samy?le of siliceous gold ore 786 grolznd for 1-1/2 hours i;l 3 ball mill and the nuln was divided into two products electri~mag-etically. The racult s follow: ]

Jan 1, 1937

By R. E. Heithecker

Zwolle oil field of Sabine Parish, La., is different from most oil producing areas of the State in that the oil is obtained from marl and chalk-rock formations. The thickness of the reservoir rocks averages 500 feet; but production is not continuous throughout this thickness, as the oil apparently is localized in vertical and nearly vertical solution cavities and channelways or in porous zones of limited horizontal extent. The nature of the oil accumulation has caused two outstanding peculiarities of the field: (1) About 60 percent of the tests drilled were dry holes and (2) there were many instances of well interference. Commercial production was discovered in November 1928, after 17 years of prospecting in and around the present limits of the area now developed which has a length of about 22 miles and a maximum width of 4 miles. The field had produced 10,266,896 barrels of oil to January 1, 1934. The oil ranges in gravity from 400 to 420 A.P.I. Although the field is divided into several districts which are more or less clearly defined and separated by unproved territory the term Zwolle field", as used in this report, includes the entire area from Blue Lake on the west side, through Zwolle proper, and eastward, including the Many or Eastern extension.

Jan 1, 1934

By John C. Ferm

This report summarizes the results of an investigation of geologic factors that contribute to roof quality in underground mines in the Pocahontas #3 coal bed in southern West Virginia and southwestern Virginia. The investigation consisted of three phases, the first of which was selecting for detailed study five mines which represented the range of roof conditions, mining practices and geologic phenomena. This was accomplished by a statistical analysis of questionnaire data from 35 mines. The second phase consisted of detailed mapping in a "good" and a "bad" top area in each of the five selected mines and resulted in a qualitative assessment of geologic factors contributing to roof £alls. In the third phase, five mines were selected in which most non-geologic factors believed to contribute to roof falls were relatively constant but displayed a wide variety of geologic characteristics. Data from these mines were analyzed to test the qualitative assessments from Phase II. The primary result of this investigation is that slickensides arising from different geologic causes are the major geologic features leading to roof falls. These slicken-sides are found in ancient slump deposits, fire clays and sandy fire clays and channel contacts. Falls also occur where thick sandstone bodies directly over-lying the coal contain abundant shale or ironstone pebbles and coaly strips. The best top material is a sequence which consists of shale grading upward to sandy shale and sandstone within 30 feet of the top of the coal. Thick sand-stone units (301) without pebbles also provide good top.

Jan 1, 1978