Search Documents

By J. F. Neill, O&apos

The manganiferous schists occurring in the vicinity of Kings Mountain, North and South Carolina, suggest significant tonnages of potential submarginal ores. Although some reconnaissance work in connection with these deposits has been reported, no recent information has been published. Evaluation of the schists as a possible domestic manganese resource has not always adequately considered the fact that the manganese content occurs quantitatively both as oxide and as the silicate, spessartite. The Bureau of Mines investigation herein reported includes preliminary studies to indicate the extent of manganese oxide mineralization and to deter-mine the amenability of the material to sulfur dioxide leaching. The field reconnaissance studies suggest a resource containing in one area an average of 6.4 percent manganese as oxide. The procurement of depth information was beyond the scope of the investigation.

Jan 1, 1962

This study estimates costs of producing bituminous coal and lignite by strip-mining methods in 12 hypothetical mines. Basic costs are developed by geographic area, rank of coal, and output capacity. Seam thickness and depth and type of overburden are considered typical for the area in which the hypothetical mine would be located. The cost analyses are based on the use of new equipment, the prevailing union wage scales, and the payment of all miscellaneous costs including royalties, contributions to the miners' welfare fund, and license and permit fees. All model mines are considered to have a life span of 20 years. Capital costs of bituminous strip mines with a capacity of 1 million tons per year range from $12.7 million in the Appalachian region to $16.0 million in the Interior province. The corresponding selling price, assuming a discounted cash flow return of 12 percent on investment, is $5.40 and $6.95 per ton, respectively. For bituminous coal strip mines producing 3 million tons annually, a capital investment of $24.9 million will render a selling price of, $3.46 per ton in the Interior province, whereas a similar mine in the Appalachian region requires a capital investment of $28.0 million to produce coal selling for $4.01 per ton. Subbituminous strip mines of 5 million tons of output per year range in capital costs from $28.7 million in the Southwest to $13.9 million in Wyoming and Montana. Coal produced in the Southwest would sell for $3.03 per ton, while coal from Wyoming and Montana would sell for $1.83 and $1.64 per ton, respectively. The capital costs for the strip mining of lignite range from $6.4 million for an output capacity of 1 million tons annually to $20.7 million for an annual capacity of 5 million tons. The corresponding selling prices of $3.01 and $2.12 per ton, respectively, Indicate the advantages of a large-capacity strip mine.

Jan 1, 1972

Sixteen papers concerned with the technology and utilization of low-rank fossil fuels are presented as the proceedings of the 1973 lignite symposium. This symposium, the seventh in a series of biennial meetings, was cosponsored by the Bureau of Mines and the University of North Dakota.

Jan 1, 1974

By Gary Friedline

As a consequence of the Coal Mine Health and Safety Act of 1969(PL91-173), the Bureau of Mines (BOM) entered into a contract with Ocean Energy Inc. (OEI) to develop, fabricate, install, and evaluate a permissible lighting system for use on a longwall coal mining operation. The program schedule is shown in Figure 1.1. The proposed regulations are contained in Appendix A. The initial part of the program involved a survey of existing longwall lighting practices in Germany and England and an evaluation of a variety of lighting components on a mockup of a longwall mining operation that was fabricated under this program. Visits made to German and British mines uncovered major differences in lighting level requirements, permissibility aspects, size, and operating constraints which identified wide disparities and essentially eliminated from further consideration any known imported lighting devices for meeting the higher lighting levels and standards proposed for US coal mines by the Mining Enforcement and Safety Administration (MESA). The longwall mockup provided use¬ful information regarding the amount of illumination required, physical size and shape of lamps, light distribution problems, cable routing, use of connectors, signaling, glare, and other important factors unique to the lighting of low coal longwalls.

Jan 1, 1975

By W. E. Robinson

Differences in the composition or chemical structure of the organic material in samples of Uinta Basin (Utah) oil shale were studied relative to stratigraphic position within the Green River Formation. This involved a systematic study of the soluble organic material and the insoluble organic material (kerogen) present in the samples. Emphasis was placed upon the distribution of the alkanes (normal and isoprenoid compounds) in the soluble extracts and upon the aromaticity of the kerogen. Significant differences exist in the chemical composition of the organic material from various strata within the Uinta Basin, some of which were related to burial depth but most were related to source material variations, environmental differences, or other factors. The Uinta Basin samples differed significantly from Piceance Creek Basin and Green River Basin samples in the large amount of soluble extract they contained.

Jan 1, 1975

By Phillip R. Moyle

A mineral survey of 19,350 acres of the Gooding City of Rocks Wilderness Study Areas (WSAs) in the north-central Snake River Plain was conducted by the U.S. Bureau of Mines in 1984. No formal mining districts are known in or near the study area. Forty-two placer claims within and adjacent to the study areas cover the Clover Creek diatomite deposit. Minor production from four pits was reported by the owners. The diatomaceous sediments are underlain by dacitic welded tuff and capped with basalt. Five exposures or blocks totaling 416 million tons of the diatomaceous material comprise the Clover Creek deposit; four of the blocks are in the study areas, out are predominantly covered by basalt. The North Clover block, just west of the areas, is only partially capped, and could be mined by open pit methods on the western flank of the exposure. The minable wedge contains an inferred marginal reserve of 35 million tons of diatomite possibly suitable for filter aid, filler, insulation, and other applications. At a production rate of 150,000 tons/year, total mining and milling costs for high-grade filter aid diatomite would be about $100/ton. The deposit is classed as marginal because products from this deposit may be inferior to currently marketed diatomite products. The market is well supplied by developed sources.

Jan 1, 1985

By Herman O. Ankenbruck

Analyses of statistical data indicate that haulage accidents are one of the largest sources of injuries and fatalities in underground coal mines, and that the rate of accidents in transportation has been increasing during the past few years. These previous analyses were performed by correlating accident or fatality data at a rather high level of miner activity. In this present investigation, underground surveys were made by observing conditions and activities in some detail at a rather low level of activity in an attempt to understand factors contributing to hazards in the specific situations observed. The aim of the current study was to derive preventive measures that might obviate the hazardous conditions and unsafe acts observed; and, following this, to provide recommendations for additional research and development to reduce accident potential in underground transportation. The major project tasks are diagrammed together with the task outputs in figure 1-1. Initially, a preliminary study of ell underground haulage operations was performed in order to establish the kinds of data needed and to provide the rationale leading to the data requirement. At the same time, the various types of haulage equipment used for each operation were defined. A preliminary analysis of each type of haulage operation was performed in order to establish the sequence of tasks required to operate haulage equipment. These tasks were transferred directly onto observation forms, and were used in developing interview forms. In parallel with the task analysis, a review was made of accidents and hazards that might occur during each type of operation.

Jan 1, 1975

By J. R. Cobble

As part of the Federal Bureau of Mines project to develop new or improved materials for metallurgical furnace applications, the Tuscaloosa (Ala.) Research Center has conducted research to develop a reproducible laboratory test for evaluating the resistance of refractories to molten slags. Tests were conducted with a slag representative of slag used to produce mineral wool. A rotating cylindrical furnace was lined with the brick being tested, and it was operated at temperatures up to 1,660° C for periods ranging from 8 to 32 hours. The effects of such variables as slag temperature, rotational velocity, charge rate, and contact time on refractory erosion were determined. The research demonstrated the reproducibility of the test procedure developed.

Jan 1, 1980

By Philip K. Hopke

A systematic study of the mechanism of interaction of 218Po(RaA) armed by the decay of 222Rn with airborne particulate matter has been made. The rate of attachment of RaA to particles in the diameter range of 0.1 µm to 10.0 µm has been measured as a function of particle size, concentration, and composition, radon concentration, time of interaction, relative humidity and temperature. It was found that under the conditions in these experiments the attachment rate was proportional to the square of the particle diameter and varied with temperature and relative humidity. The composition of the particles apparently has no effect on the attachment. The variation in attachment rate was related to a sticking probability coefficient of approximately 0.02 that varies systematically with temperature and humidity. In addition, the rate of deposition of RaA on the wall of the attachment kinetics system was measured and also found to change with temperature and relative humidity.

Jan 1, 1980

By John M. Popovich

Disposing of coal mine waste at the surface has been and continues to be a problem which has yet to be resolved within the coal mining industry. A possible solution to this problem is to return the refuse back into the operating underground mine generating the waste material. It is believed that the approach described will provide an inexpensive and pratical solution to the problem. The designed system is installed and operable at the Millers Cove Energy Company, Inc. property in Lee County, Virginia. This system limits surfact facilities to a minimum size. It incorporates state-of-the-art hydraulic transport and backfilling technology and equipment to systematically backfill areas within the active mine. It maximized the benefits of reducing treatment of coal wasts while it minimizes environmental impacts on groundwater. The system approaches the problem in a manner to maximize benefits and minimize risks. The cost of returning coal waste back underground at the Millers Cove site is estimated at $0.67 per ton of marketable coal (1982 dollars), which is slightly higher than their surface disposal cost of $0.61 per ton of marketable mat (1982 dollars). The underground disposal costs do not include cost savings that should be realized within the preparation plant and treatment facilities at the surface. Preliminary tests of the system were conducted at the surface; funding restrictions prevented an in-mine trial. Efforts should continue to demonstrate the feasibility of solving the problem of refuse disposal. The installed system and plant at Millers Cove should provide the opportunity to test an underground disposal operation. This report contains guidelines to pursue this opportunity.

Jan 1, 1986

By Ronald Branstetter

Gaseous and particulate exhaust emissions from 20 diesel engines in service at five underground mines were measured with high accuracy instrumentation. The engines that were tested were checked for faults or maladjustments. The vehicle and engine maintenance organization was studied at each mine and an idealized maintenance program was devised. Faults were induced in a new diesel engine to determine their effect on the characteristics of the exhaust emissions. The results, conclusions and recommendations from this investigation are presented in this final report.

Jan 1, 1983

By W. W. Aljoe

The use of protective canopies can result in canopy roofing and/or serious restrictions to operator comfort and vision. To document this experience, BCR conducted a field study of cab and canopy design and application which resulted in a catalog of 164 canopy designs and an analysis of field data which showed no simple relationship between working height and canopy-related problems. The relationship also involves (1) machine frame height, (2) mine floor undulations, (3) operator compartment dimensions, (4) canopy design and location on the machine. Data analysis indicates (1) present technology does not always permit successful application of canopies in working heights below 42 inches, and (2) development of satisfactory low-coal canopies is doubtful. The basic conclusion of the study is that future R&D studies should be directed at development of alternative protection systems and remote mining methods.

Jan 1, 1981

By David C. Benson

This Bureau of Mines report is an update of IC 8725 and comprises tables listing the name, location, and other pertinent data concerning certain fuel-related projects. The tables include information on projects involving the proposed or planned development of fuel resources, as well as the development of storage, transportation, and conversion facilities; the report covers the 26 States east of the Mississippi River. Of the total 535 projects for which information is provided, 429 concern coal mines and electric generating plants (including Energy Supply and Environmental Coordination Act (ESECA) coal conversion notices).

Jan 1, 1978

By C. Harry Benedict

This paper presents the details of milling practice and costs at the conglomerate mill of the Calumet & Hecla Consolidated Copper Co., Lake Linden, Mich., and is one of a series on milling methods being published by the Bureau of Mines. GENERAL DESCRIPTION The mines of the Calumet & Hecla. Consolidated Copper Co. are located in the Keweenaw Peninsula of northern Michigan. The mines of this district lie in a belt not over 4 miles wide and 100 miles long, which contains more or lees commercial ore. The Calumet & Hecla properties are the farthest north, except for the Seneca, of the operating mines. The district borders on Lake Superior, and by means of the Portage and Torch Lake waterways the largest lane vessels, can transport coal and other supplies from the lower Lakes directly to the company docks.

Jan 1, 1930

By Russel Bohn

The purpose of this study was to evaluate the various techniques far mine roadway dust control. This evaluation included (a) the types of dust suppressants available, (b) the interaction of these products with the properties of the roadway surface, and (c) the costs and performance measures of the predominantly used dust suppressants. Over 30 products were identified having a wide range of effectiveness depending largely on the properties of the road base, subsurface, and wearing surface. The effectiveness of a dust suppressant was also found to depend on the application and maintenance procedures employed. As a result of this investigation five dust suppressants were identified s being predominant in the surface mining industry: Coherex, wetting agents, lignin sulfonate, water, and calcium chloride: An approximate cost-effectiveness analysis, limited by the lack of quantitative field performance data, showed that the five suppressants ranked in the order given above, with water being one of the least cost effective. This report also presents an analysis of applicable federal and state regulations.

Jan 1, 1981

By Dennis E. Jensen

Field studies were performed during blasting operations for strip coal mining above the room and pillar workings at Jenny mine in eastern Kentucky. The study is part of the Bureau of Mines program to develop criteria for the proximity of surface blasting to underground mines. Measurements and observations were made to identify physical changes in the mine. No change in the frequency of roof falls or any other indication of apparent damage was noted. Recordings of blast induced vibrations were made using sensors on the roof and floor of the underground mine and at the ground surface. A maximum particle velocity of 17.5 in/sec was recorded on the mine roof. The vibration data were analyzed and comparisons were made between roof vibration levels and those recorded on the mine floor and at the ground surface. Results are compared with previous blast vibration studies. Recommendations are made for further study toward developing criteria.

Jan 1, 1979

By G. R. Moulder

A device was developed that measures dynamic stress (ultrasonic energy) transfer through installed rock bolts, a measure that is directly proportional to the degree of grout bonding of the bolt to the mine roof structure and thus the ability of the bolt to bear static stress. The rock bolt bond tester (RBBT) is a hand-held portable device that shows three ranges of bolt bond condition; i.e., one-third (Bad bond), two-thirds (marginal), or fully bonded. These are shown respectively by a red, yellow, or green light that displays for 4 s. RBBT performance was verified with 2 1/2-to 8-ft bolts installed in various types 0f mine roof structures (sands tone, shale, and boney coal-mud), and 15 now being tested by the Bureau of Mines in mines across the United States. The unit is about the size of a five-battery flashlight and contains the transducer electronics, and battery pack. The RBBT is designed for extreme ease of operation, requiring only manual contact with the bolt and signal read-out. The batteries are rechargeable and the package is designed for durability in a mine environment.

Jan 1, 1983

By John G. Palmer

Continued development of an especially impregnated silica gel capable of reversible chemical detection of carbon monoxide (CO) was reported. The affects of changes in mine-related ambient conditions on the detection catalyst's response were explored. Temperature, humidity, and several interfering gases were found to affect the detection catalyst. The interferents include hydrogen sulfide, nitrogen dioxide, acetylene (and methylacetylene), and ammonia. High humidity decreased the detection catalyst's sensitivity to carbon monoxide for some formulations. Increasing temperature generally decreased the reaction time of the detection catalyst with carbon monoxide. Badges and carriers for the visual presentation of the detection catalyst were constructed. Several variations of these devices included provisions for absorbants and filtering agents which help protect the detection catalyst from gaseous interferents. A variety of catalyst support agents were tested in an effort to find the most suitable. Included were alumina, magnesium oxide, magnesium silicate, and several forms of silica gel. In addi tion to free-flowing forms of these sorbents, thin layer chromatography plates coated with cellulose, alumina, and silica gel and newly developed PTFE entrained silica gels were examined. A limited physical, chemical, and mechanistic characterization of the detection catalyst and the materials used to prepare it has been carried out. Metal component ratio studies, spectral, analytical, pH, and rate measurements were done.

Jan 1, 1982

By Wesley T. Holmes

This report describes the second phase of an investigation aimed at obtaining a wider knowledge of the problems involved in smelting titaniferous magnetites. Liquidus temperature measurements were made on selected synthetic slag compositions in the Ti02 -A1203 -FeO-Si02 -CaO-MgO system. Both the hot-stage microscope and the strip furnace (melting-holding-quenching technique) were used during test procedure to determine the effects of CaO, MgO, and SiO2 on the liquidus temperature of slags. The liquidus temperatures of slags studied ranged from 1,241° to 1,900° C. The lowest liquidus temperature for each Ti02 plus A1203 plus FeO weight-percent generally occurred when the difference between CaO plus MgO and Si02 was less than 12 weight-percent. In this investigation substitution of either CaO or MgO for SiO2 and MgO for CaO raised the liquidus temperature of more than 50 percent of the reported base slags when Ti02, A1203, and FeO contents were held constant. The results of this investigation may serve as guidelines for determining flux requirements in smelting a wide variety of titaniferous magnetite concentrates or ores.

Jan 1, 1968

By Bruce I. Thomas

Reconnaissance studies of beach sands along the eastern part of the Gulf of Alaska were conducted by the Bureau of Mines to determine if any of these coastal areas warranted investigations as possible sources of valuable minerals. Because of difficult access and limited transportation facilities only a minimum of sampling, surveying, and camping equipment is utilized to obtain spot samples from key areas as well as information indicating the location, size, and character of the deposits. Such data were obtained from beaches located along approximately 247 miles of the Gulf of Alaska coastline during parts of the 1957 and 1958 field seasons. A total of 201 3-inch-diameter auger holes, spaced roughly at 1 mile intervals, were bored by hand methods to depths ranging from 3 feet to 27 feet; also 33 shovel samples were collected from selected localities. Samples were reduced to a rough concentrate in the field by panning; the rough concentrates were shipped to the Bureau of Mines laboratory at Juneau for further concentration and for petrographic and chemical analyses. Particular attention was given to the heavy-mineral content of the concentrates, although the types and relative amounts of rock-forming minerals were also determined. The reconnaissance indicated that, generally, the valuable mineral content of the beach deposits was too low to be of further interest except in the vicinity of Yakutat and Lituya Bays where erratic but possibly significant concentrations of magnetite and/or ilmenite were found. At Yakutat, about 20 miles of beachline extending southeasterly from Ocean Cape, yielded samplas containing from 1 pound to over 300 pounds of iron and from a trace to over 100 pounds of titanium dioxide (TiO2) per cubic yard of beach material. However, the higher grade samples represented local concentrations of minor importance. The general tenor of the Yakutat beach, as indicated by the airthmetical average of 27 auger-hole samples, is about 35 pounds of iron and 20.5 pounds of titanium dioxide per cubic yard of beach material. Ilmenite is the predominant heavy mineral of the beach deposits in the vicinity of Lituya Bay, but it was found in concentrations only in limited areas near the

Jan 1, 1962