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By H. M. Cooper

Many analysts have had difficulty in obtaining accurate and consistent determinations of the volatile matter in low-temperature coke when the usual standard method for coal was followed. The tendency is toward too-high results, due to mechanical losses which are extremely difficult to avoid or control. With cokes there also may be an error due to excessive oxidation of the fixed carbon. Much of the earlier experimental work on the volatile-matter determination in coal, such as that of Parr,5 Fieldner and Davis,6 and others, 7 has been on the effect of time, temperatures, shape and size of crucibles, method of applying heat, and type of furnace, all of which data has evolved the present A.S. T. M.8 standard method for volatile matter in coal and coke. It is not the purpose of this investigation to deal directly with the above phases of the procedure, but rather to study some of the factors affecting she results in those types of fuel which give erroneous results due to mechanical losses.

Jan 1, 1932

By D. Randolph Berry

Foster-Miller Associates has developed a set of guidelines to permit hoist manufacturers, mine owners, and MESA mine inspectors to design, purchase, install or inspect a safe and effective Emergency Escape Hoist, as required by the Coal Mine Health and Safety act of 1969. A series of surveys were carried out to determine: 1. The attitudes and local needs of the MESA District Managers. 2. Current escape hoist installations. 3. Equipment available for future designs. 4. Foreign methods and equipment for mine rescue. From these survey studies, preliminary guideline objectives were developed.

Jan 1, 2012

By C. A. Rhoades

The spillage that accumulates under conveyor belt lines presents a possible fire and explosion hazard fomiinqjetsoruiel, especially to those who must clean up the spillage. The U.S. Bureau of Mines conducted research to reduce this hazard by identifying and investigating the parameters affecting the efficiency of conveyor belt cleaning. The amount of material carried back under the conveyor and the wear rates of metal cleaning blades decreased with increasing blade-to-belt pressure to a limiting value, after which the carryback and wear rates remained essentially constant. The optimum blade-to-belt pressure was found to be 11 to 14 psi for the research conveyor system. Greater pressures increased the blade-belt friction without improving either cleaning or blade life. The modes of blade wear were three-body abrasion and slurry erosion caused by the sand-lime test mixture. Wear rates were reduced by increasing the metal hardness, opti-mizing the pressure, and removing conveyor belt imperfections. Corrosion was not observed to affect the wear of various steels in tests of less than 34 h. The results of this study should allow mine operators to run their conveyors under conditions that will maximize cleaning and minimize equipment wear.

Jan 1, 1989

By H. E. Powell

A laboratory investigation was conducted by the Bureau of Mines to study the magnetic characteristics and to measure the magnetic susceptibility of the mineral siderite. All susceptibility measurements were made by the method of Gouy on powdered samples and at room temperature. Specific susceptibilities of samples from 15 different locations, domestic and foreign, were determined. Values ranged from 66 to 103 (10-6) cgs electromagnetic units. The relation of susceptibility to mineral composition is discussed in this report. The specific susceptibilities of 76 minerals are tabulated in an appendix.

Jan 1, 1963

By D. A. Paice

Under the first phase of this contract as reported in the Phase I report it was determined that certain types of commercially available molded case breakers are capable of interrupting mine dc power supplies of nominally 300 volts or 600 volts rating. These circuit breakers incorporate conventional overcurrent trip units but also can be operated by means of low power signals fed to a shunt trip coil. Further development in the Phase I program produced a means whereby a discriminating circuit breaker detector unit could sense the presence of illegitimate loads on the dc electrical system and cause the circuit breaker to trip. The detector unit operated by detecting the presence of 3000 Hz currents which were generated in the illegitimate loads by means of a 12 volt, 3000 Hz signal applied to the dc system. Further development of the program has continued in Phase II with the aim of verifying the practicability of the complete discriminating circuit breaker concept and developing other types of equipments required to implement a system. These other equipments include electronic means for raising the apparent impedance of high power legitimate loads and static filters for smaller loads. The results of laboratory work and limited underground tests have been successful. This report describes the system and the tests that have been conducted on the various equipments that comprise the complete Discriminating Circuit Breaker Concept.

Jan 1, 2012

By Clayton M. Rumsey

The U.S. Bureau of Mines conducted a mineral resource survey of the Cinder Cones Wilderness Study Area (WSA) (CDCA-239), 10 miles east of Baker, CA, in 1983. The 44,299-acre WSA is underlain by Precambrian granite gneiss, Upper Cretaceous or lower Tertiary Teutonia quartz monzonite, and Quaternary basalt flows and alluvium. This mineral survey included an examination of two volcanic cinder mines, five lode prospects, two volcanic cinder prospects, and reconnaissance sampling in and near the WSA. The seven prospects are in the WSA; the two volcanic cinder mines are adjacent. No mines are in the WSA. In 1981, there were 61 placer and 3 lode mining claims in the WSA. Sample results from two prospects within the WSA contained significant gold and silver values; however, the mineralized rock is of limited extent and no resources were apparent. Alluvial samples taken throughout the WSA contained only traces of gold. Two volcanic cinder cones within the WSA contain an estimated 30 million tons of cinders. There are sufficient cinders outside the WSA to satisfy demand in the foreseeable future. Stone, sand, and gravel deposits are not resources because similar material is closer to markets. No evidence of energy minerals or geothermal resources was found.

Jan 1, 1985

By M. C. Irani

The Bureau of Mines, in cooperation with the Mine Safety Appliances Co., has developed a continuous-recording methanometer utilizing a catalytic combustion detector. The methanometer, which is presently operating at 22 exhaust fans at 14 mines in the Eastern coalfields, is reliable and simple to install, operate, and maintain. The instrument and the details of its installation and calibration are described. Analytical data obtained by infrared spectrophotometer and gas chromatograph are presented to substantiate its re liability.

Jan 1, 1974

By Paul Hatmaker

Pumice and pumicite are siliceous volcanic substances quite similar in chemical composition , but somewhat different in physical properties , manner of formation , and mode of occurrence . Production in the United States has increased from 23,271 tons valued at $ 94,943 in 1910 , to 56,843 tons valued at $336,099 in 1930. Both pumice and pumicite are included in these figures as it has been impractical to collect statistical data on the separate commodities .

Mar 1, 1932

By R. Emmett Hughlett

The Bureau of Mines has developed a statistical approach to the laboratory evaluation of response bias and precision in gas detectors. The techniques described employ a computerized analysis and a new method of data presentation called composite graphing. The underlying theory, its practical application to the data, and the experimental equipment and procedure are described.

Jan 1, 1982

By W. L. Dare

Tri-axial strains in pillars, created by pillar robbing, were measured in an experiment at the Dysart No. 1 uranium mine near Grants) New Mexico. At this mine, room-and-pillar stoping is used on the advance, and pillars are recovered on the retreat. The are deposit is, for all practical purposes, horizontal. Measuring devices were installed in pillars approximately 90 to 200 feet from the break line, and strains were recorded over a 4-to 6-week period. The measurements indicate that, in general, the algebraic magnitude of vertical strains increased, and the horizontal strains decreased, in turn, indicating that vertical (or near vertical) loads on the instrumented pillars lessened as pillars were recovered.

Jan 1, 1962

By Wils L. Cooley

This report analyzes electrical accident data in the metal/non-metal mining industry. Accidents are categorized to determine their root causes. Special attention is given to accidents associated with inadequate or defective grounding of mine power systems. Recommendations are made concerning proper grounding practice, especially for dredges and for quarries in hard rock or sand. The costs of instituting the recommended practices are estimated for model mine power systems which are based on field data obtained from 37 mines and several electrical contractors. The expected benefits of various suggested safety practices are also estimated.

Jan 1, 1981

The following report summarizes the results of engineering feasibility studies whose purpose was to assess the probable efficiency, reliability, safety and cost of a number of possible methods for removal of radon gas from the ambient air in underground mines. Fourteen candidate techniques were evaluated. Seven of these were based on specific individual principles, and seven were based on combinations of these principles. The individual principles were as follows: 1. Activated charcoal 2. Organic fluids 3. Semipermeable membranes 4. Molecular sieves 4. Cryogenics 6. Chemical reaction 7. Centrifuge The combinations were: 8. Cryogenics and activated charcoal 9. Cryogenics and molecular sieves 10. Cryogenics and chemical reactions 11. Membrane filters and organic fluids 12. Membrane filters, cryogenics and activated charcoal 13. Membrane filters and chemical reactions 14. Silica and an Organic Fluid

Jan 1, 1975

By Raja V. Ramani

The potential usefulnuss of reclaimed surface-mined land has received much attention in recent times. This attention is partially due to the establishment of federal environmental reclamation standards but concern for achieving better land uses has also been shown by interested members of the mining industry. In an effort to develop a procedure for evaluating postmining land use potentials, specific mines in various regions of the U. S. were studied to determine the extent of current mined-land planning and to discover characteristics that are regional in nature. As part of this investigation, a 430-acre surface mine in Clear-field County, Pennsylvania has been studied. Established site planning principles have been applied to the case study site including formation of a data base, development of alternate land use plans, and evaluation of the economic, environmental, and social impacts of the land use alternatives. Key factors affecting site realization have been identified along with positive suggestions for applying land use planning processes to mined-land planning.

Jan 1, 1983

By Tuncel M. Yegulalp

The objective of this study was to categorize mining operations in the stone, and sand and gravel industries into areas of similar ground control functions and define initial factors affecting operational safety in each area, by means of utilizing publicly available data, telephone interviews and on site observations. The findings and recommendations presented in this report are based on the information collected during the two phases of the project. They also contain, in part, the collective qualitative opinion of the operators with respect to government rules and regulations on ground control safety and the implementation of these rules and regulations by government inspectors.

Jan 1, 1981

By Ronald P. Hollenbeck

This study reviews and discusses the fluorspar industry in the Eastern United States, with emphasis on factors controlling the industry such as production, consumption, uses, and transportation. The greatest potential for increased consumption of fluorspar in the immediate future was found to be in the manufacture of fluorine chemicals and steel. Important factors affecting the future domestic industry include imports and the maintenance of adequate domestic fluorspar reserves. Exploration, commercial deposits, mining and milling, reserves, and new developments in the industry are covered.

Jan 1, 1967

By J. R. Thoenen

In June 1929 the Bureau of Mines issued a 13-page information circular entitled "Mineral Wool," which was one of the first publications to present to the public Rome technical aspects of the mineral-wool industry. Since then several articles on the subject have appeared in the technical press as well as in publications of State organizations. Inquiries for information on mineral wool have continued to be received by the Bureau of Mines in large number, and in 1935 it was decided to make a field survey of the plants then producing and to collect therefrom technical data to be compiled in a paper for nubile distribution. With the cooperation of the industry, this survey was made, and Information Circular 6984, Mineral Wool, was published in January 1930. The issue was exhausted after a few months, and requests for copies continued to come to the Bureau. As opportunity arose, further field studies were made in American as well as Canadian plants. The present circular contains the essential information in Information Circular 6994 together with date from later field studies.

Jan 1, 1939

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 William A. Beck

The Construction Aggregates Corp. operates a plant for processing sand and gravel from two deposits in Ottawa County, Mich. The bulk of the sand is obtained from a sand dune on the shore of Lake Michigan, and the gravel is dug from a glacial-drift deposit farther inland. Mining is done with draglines, and the material, both at the digging site and in the plant, is moved mainly by systems of conveyors. The Ferrysburg plant serves customers along the Great Lakes, which is unusual for a business normally local in character. Annual production exceeds 1-1/2 million tons of sand and gravel as concrete aggregate and 200,000 tons of core sand for foundry use.

Jan 1, 1962

Severe whipping of shuttle car trailing cables occurs when the car stops suddenly or reverses direction. This causes cable damage, and can seriously injure personnel near the cable. FMC has contracted with the U.S. Bureau of Mines to design, build and demonstrate a reel control system that will significantly reduce or eliminate whipping. II. CONCLUSIONS Results of engineering effort show that the following conditions are primarily responsible for the whipping problem. Causes may exist individually, or in combination.

Jan 1, 1972

By G. F. Kuncir

The time-cost-risk analysis described herein was performed as part of an evaluation of the Advancing Oil Shale Mining Technology Program performed by The Aerospace Corporation. The objectives of this analysis are to assess the feasibility of the program relative' to time and cost constraints, and to determine the probabilities of achieving various technological goals. A combination of standard program planning and analysis techniques were used to achieve these objectives. These included a critical path analysis, a resource allocation analysis, and a risk analysis.

Jan 1, 1977