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By Irving Wender

This report describes Bureau of Mines experiments and reviews the work of others on the exposure of coal and coal-derived products to gamma rays and some other types of radiation. Results are presented on tests of three bituminous coals and a lignite that had been pulverized to minus 200-mesh particles and exposed to 1,000 megaroentgens of gamma irradiation from spent-fuel elements of a nuclear reactor. Of about 20 chemical and physical tests in Bureau work, only mass spectrometry of gases evolved during vacuum pyrolysis of the coals to 450° C gave results indicating differences in the irradiated and unirradiated samples. Mass-spectral distribution curves for CO and CO2 evolution showed fewer irregularities (reversals of curvature) for irradiated coals; thus, mass spectrometry appears to be the most sensitive method for determining radio-induced changes in coal. It is concluded that coal is not significantly altered by gamma irradiation owing to the resistivity of its highly condensed ring structure. High-level gamma irradiation, therefore, is unlikely to prove advantageous in coal processing and utilization. Specially treated coals, because of resistivity of coal to radiation damage, may be useful as an absorbent in processing radioactive wastes.

Jan 1, 1968

By E. D. Gardner

This paper is a progress report on the study of mining methods and costs in the western United States and summarizes that part of the work pertaining to the undercut block-caving method of mining. Ore is mined on a large scale exclusively by the undercut block-caving method at the following six mines in the western United States: The Morenci branch of the Phelps Dodge Corporation, Morenci, Ariz.; the Ray mines of the Nevada Consolidated Copper Co. at Ray, Ariz.; the Inspiration Consolidated Copper Co. at Inspiration, Ariz.; the Miamo Copper Co. at Miami, Ariz.; the Ruth mine of the Nevada Consolidated Copper Co. at Ruth, Nev.; and the Consolidated Coppermines Corporation at Kimberly, Nev. The undercut block-caving method is also used at the mine of the Andes Copper Mining Co. at Potrerillos, Chile.

Jan 1, 1930

By S. H. Ash

THIS REPORT covers the third in a series of five projects into which the Conowingo tunnel system has been divided for geographical and practical reasons. It outlines the work constituting Project No.3 that consists principally of the following: (a) To sink the No. 15 shaft and extend the Alden, Sugar Notch, Baltimore No.2, and Laflin shafts from their present depths to tunnel level; (b) to drive a tunnel off these shafts to connect with the western end of the tunnel in Project No.1 (Lackawanna) and to a point 1 mile south of the No. 15 shaft; (c) to construct an emergency pumping plant at the No. 15 shaft, complete with 3 centrifugal pumps of 200-cubic-foot-per-second (c. f. s.) capacity each, and a discharge-water shaft and a discharge tunnel for conducting the water from the pumping plant into the Susquehanna River; and (d) to construct a lateral tunnel 1 mile long off the main tunnel in the vicinity of the No. 15 shaft, to be known as the Wyoming lateral. The project, as outlined, is a self-contained drainage unit that will permit unwatering inundated mines and safeguarding active mines in the Wyoming Basin of the Northern field and also will handle the water in the Lackawanna Basin, thus permitting the temporary pumping plant provided in Project No.1 to be discontinued. The pumps installed in the temporary pumping plant provided in Project No.1 can then be moved to the emergency pumping plants recommended in Projects Nos. 2 and 3, to be installed as the third or standby unit.

Jan 1, 1955

By J. C. Johnson, W. G. Pariseau, D. F. Scott, F. M. Jenkins

In situ stresses are important input data for the design of safe, stable stope layouts and extraction sequences. However, it is commonly assumed that normal and shear stress gradients in a stress field are negligible and, consequently, that stresses are uniform throughout the region of analysis. To evaluate these assumptions and to provide input data for an analysis of a shaft pillar mining plan, in situ stresses were measured at the Homestake Mine, Lead, SD, using overcoring on hollow inclusion cells and borehole deformation gauges. These measurements were used with conventional least squares, best fit data reduction schemes. The results showed that normal stresses within the shaft pillar were less than, but comparable to, those estimated from finite-element modeling. Shear stresses were an order of magnitude less than normal stresses and varied considerably from site to site. Possible causes of this variability include effects of scale, elastic moduli, anisotropy, and axial strain. Because of the variability, it is not possible to determine the magnitude of horizontal stress gradients.

Jan 1, 1993

By Thomas Gales

Longwall mining has a high potential for producing bulk production from a single face. Production is interrupted for a considerable time when it is necessary to move the equipment to a new block of coal. The frequency of such moves can be reduced by increasing the dimension of the block to be moved. Merely doubling the tonnage in a block to be mined may increase production by more than 21,000 tons per year. The time taken to move the equipment can be reduced by careful preplanning, industrial engineering analysis, and specially designed equipment. Reducing its move time from 30 days to five days can increase production by more than 25,000 tons per year. Increasing the panel dimensions and reducing the move time can give an increase in pretax profits of more than $600,000. A comprehensive bibliography is included.

Jan 1, 1977

The accompanying supply/demand flow diagrams and 10-year tables for mineral and fuel commodities present essential data required by government, industry, and others to formulate policies and programs that can help assure an adequate and continuing supply of mineral raw materials. The 10-year data base terminates with 1973 figures because adequate world information was not available beyond that date. Moreover, 1974 was an anomalous year with respect to prices, supply, and demand for many commodities. The selected mineral supply/demand tables and flow diagrams comprise but one "output" from the massive body of "information and data collected and com-piled by the Bureau of Mines on a continuing basis covering mineral production consumption, prices, shipments, imports, exports, and stocks, as well as industry activities in all States and abroad.

Jan 1, 1975

By Robert L. Montgomery

Heats of solution of samarium (III) oxide and chloride in hydrochloric acid and of samarium (III) oxide, sulfate, and hydrated sulfate in sulfuric acid were measured. The heats of solution of this hygroscopic oxide are larger than those from the literature, probably because of more complete removal of water in the present study. From the literature value for the heat of combustion of samarium, the heats of formation of samarium (III) chloride and sulfate are -244.18 ± 0.41 and -928.5 ± 1.6 kcal./mole, respectively. The heat of hydration of the sulfate is -34.7 ± 1.0 kcal./mole. The heats of formation of other samarium com-pounds have been recalculated, using the new data.

Jan 1, 1959

By A. L. Peyton

Manganese-oxide minerals occur in irregular pockets distributed through the residual clays of the Cartersville district, which lies 45 miles north-west of Atlanta in Bartow County, Ga. The district produces, or has produced, limonite, barite, specular hematite, ochre, ferruginous manganese, manganiferous iron are, as well as manganese. Bureau of Mines engineers have visited the district on three occasions - in December 1939, February 1941, and October 1942. During the visit of February 1941, 80 tons of samples of manganese-bearing clays were taken from seven properties for ore-dressing tests, which were conducted at the Bureau of Mines laboratory at Rolla, Mo. The. October 1942 visit was for the purpose of reappraising the district in the light of knowledge gained from the ore-dressing studies and to prepare a plan for the district's development. Exploratory drilling was begun in March l943 and was continued until June 1945. Nine properties were explored that, roughly follow a line beginning near Cartersville and extend to a point 2 miles northeast of the village of White. The work consisted of bulldozer trenching, rotary bucket churn drilling, sampling, and analytical determinations. The manganese district is 18 miles long with a maximum width of 7 miles at Cartersville, which lies at the center of the district. The work of the Bureau was confined to the northern half of the district between Cartersville and Pine Log. The properties explored comprise but a small portion of the Potential producing area.

Jan 1, 1949

By L. R. Burdick

Anthracite barley is considerably cheaper than rice. Its use, therefore, is attractive from a cost standpoint, - but its smaller size (through 3/16 inch over 3/32 inch round-mesh screen) makes it more difficult to use on some equipment when fairly high combustion rates are necessary to carry plant loads. Tests wore made in one plant to determine the performance of rice and various types of barley on a chain-grate stoker in a two-arch refractory furnace. In general, the efficiency and capacity increased with increased fuel size and volatile content. This performance is presented in tabular and curve form, together with a short review of the ignition and burning process on chain-grate stokers and a discussion of the operating procedures and limitations during the tests. In this particular installation, higher combustion rates and efficiencies could have been obtained with barley if the grate links had been designed for more uniform air flow through the grate surface. Careful maintenance and operation are particularly necessary for satisfactory results with barley on equipment not especially designed for its use.

Jan 1, 1950

By Oliver Bowles

The various Latin American countries are undergoing a slow process of industrialization. The harvesting of one or two agricultural commodities or the mining of a few marketable minerals is being supplemented by development of an Integrated industrial economy. In many countries, progress in this direction has not been rapid, but as it gains impetus an increasing market for cement is a natural consequence. This is evident from the fact that industrialization is linked with increasing transportation, and means of transportation are very poor in much of Latin America. Bridges, culverts, and concrete Highway's, now scattered sparingly throughout the vast land areas south of the United States, must multiply as the demands of industry increase and as a higher scale of living is attained. Eventually the South American countries will be linked by modern highways. Furthermore, the arid climate of many regions creates a demand for construction of dams and irrigation works, and a continent poor in coal reserves but with abundant water power inevitably must direct its energies toward the construction of hydroelectric power plants. Countries rich in raw materials but with few natural harbors have urgent need of massive concrete breakwaters and docks. The demand for concrete in houses will also grow. Standards of living are low, and perishable building materials are widely used. As living conditions improve cement will be used increasingly in home construction. Even in the field of simple and modest housing cement affords a means of creating low-priced verminproof and fireproof homes, for which the need it imperative under climatic conditions that prevail in this area of the world. Already many of the countries have undertaken extensive public works, and such programs are likely to increase. Assuming moderate industrial progress and stabilized governments the demand for cement in this great southern area promises substantial growth.

Jan 1, 1940

By M. N. Rubin

This report summarizes the work performed under USBM contract J0100018. The purpose of this work was to document the currently available noise control techniques that can be incorporated into new coal preparation plants during the design stage. This was accomplished by reviewing the related experience of the contractor and subcontractor (Bolt Beranek and Newman Inc.), conducting an extensive literature search, visiting operating coal preparation plants, and contacting various equipment manufacturers. The treatments addressed include equipment substitution, changes in plant layout, and retrofit treatments for existing equipment.

Jan 1, 1982

By A. M. Kiwior

In 1969, the Congress of the United States declared that "the first priority and concern of all in the mining industry must be the health and safety of its most precious resource - the miner," Therefore, Public Law 91-173, Federal Coal Mine Health and Safety Act of 1969, was enacted. Since haulage accidents account for a high percentage of coal mining accidents, Section 314e, ?Hoisting and Mantrips,? was included in the law. This section states: "Each locomotive and haulage car used in an underground coal mine shall be equipped with automatic brakes, when space permits. Where space does not permit automatic brakes, locomotive and haulage cars shall be subject to speed reduction gear, or similar devices approved by the Secretary which are designed to stop the locomotive and haulage cars with the proper margin of safety."

Jan 1, 1975

By J. R. Thoenen

The enormous and constantly increasing demand for limestone to supply a multitude of uses is a remarkable feature of the mineral industries. As approximately 130,000,000 tons of limestone are produced annually, it is not surprising that deposits at or near the surface are gradually being exhausted and that less advantageous supplies are being worked. Quarries are becoming deeper and wider year by year, and in many places the volume of overburden that must be removed to allow open-pit work has increased alarmingly. Quarrymen are also gradually learning how expensive it is to sort and clean stone from a deposit overlain by poor material. As such conditions confront the limestone industry, the natural tendency is to seek some modification in method whereby the handicaps of increasing cost may be met and overcome. Operators, some of them unwillingly, have been forced to conclude that underground work in drifts and tunnels is the most logical solution of the problem. The unwillingness of some is largely due to unfamiliarity with mining and to the unfounded fear that costs must increase and dangers multiply when mining is undertaken.

Jan 1, 1926

By K. L. Paciorek

The aim of the present study was to determine the thermal oxidative behavior of materials used in coal mines, with emphasis on the type and relative concentration of the products, in particular the toxic species formed. To supplement this work and to gain understanding as to the type of products possibly formed and also to assess the limitations and advantages of the various analytical methods used a literature survey of the past investigations performed on the compositions of direct interest to the subject program was conducted. The compositions thus covered were cellulose, polyvinyl chloride, neoprene, urethanes, polyamides, polyesters, polyethylene, epoxy, phenoxy, urea-formaldehyde and melamine formaldehyde resins. The results of this review are compiled in the Appendix. The experimental work consisted of thermal oxidative degradation of 36 materials and 4 composites using a stagnation burner apparatus developed in these laboratories which affords a dynamic system approximating somewhat the conditions encountered in underground coal mines. This technique as employed during this program gave only the relative product concentration at specific periods of the decomposition process, The advantage of this approach is that in this manner screening of materials can be accomplished in conjunction with some assessment of the decomposition rate as influenced by temperature and material composition. Limited static tests were performed using a sealed tube method. The materials studied were grouped according to their compositions. The following were the main groups: (a) polyvinyl chloride-containing materials, (b) neoprene compositions, (c) rigid foams (urethanes, isocyanates), (d) miscellaneous materials (including jute, fiberglass, polyethylene and some articles of unknown composition), (e) coal and fluids (phosphate esters, organic esters, oil-water emulsions), and finally (J) composites. The latter comprised a mixture of a phosphate ester fluid with (a) coal, (b) a representative polyvinyl chloride sample, and (c) a neoprene type composition.

Jan 1, 1972

The research described in this report was conducted under a cooperative research agreement between the U.S Bureau of Mines Twin Cities Research Center (TCRC), Cleveland-Cliffs Inc. (CCI), and three operations in Northern Michigan managed by CCI: the Empire and Tilden surface taconite mining operations, and the Central Shops maintenance facility. All of these operations are in or near Ishpeming, MI. The Human Factors Research Group at TCRC is responsible for designing, planning, and conducting the research, and reporting on the findings. This project was carried out in order to investigate the high prevalence of back injuries being experienced by workers employed at the three CCI Northern Michigan sites, In an analysis of Company accident records for workers employed at these sites, it was determined that back injury problems confronting the CCI sites mirror those confronting the entire mining industry.

Jan 1, 1994

By Harry H. Ku

In December 1975, a report entitled "An Evaluation of the Accuracy of the Coal Mine Dust Sampling Program Administered by the Department of Interior" [1] was prepared by the Analytical Chemistry Division of the National Bureau of Standards (NBS), in response to a request by Senator Harrison A. Williams. Chairman, Committee on Labor and Public Welfare. The report attempted to evaluate the adequacy of (1) the personal sampler unit used to measure the coal dust concentration in the mines, (2) the procedures used by the Department of Interior (DOI) to analyze the dust samples obtained from mine operators, and (3) any recent studies made by the Department or private industry concerning the coal dust sampling equipment. Recommendations in the report of NBS included continued research efforts by the appropriate organization to correct the personal sampler deficiencies and to consider the use of area or stationary samplers as a supplement to the personal samplers. Concurrent with the NBS report cited above, the General Accounting Office (GAO) also issued a report in December, 1975 [2], suggesting that improvements are still needed in coal mine dust sampling programs and procedures relating to penalty assessments and collections. Among recommendations made by GAO, the following paragraph specifically called for actions by the agencies involved:

Jan 1, 1979

By Clarence Karr

In 1955 the Federal Bureau of Mines established a low-temperature tar laboratory at its new Appalachian Experiment Station in Morgantown, W. Va. The objective of the laboratory is to investigate the yields and chemical and physical properties of tars from low-temperature carbonization of coal, to investigate means of economically upgrading these tars, and to make available to industry and the public essential data for increasing coal utilization through the establishment of a new coal-chemical industry, based on the utilization of low-temperature tars. Because of the obvious economic significance of phenols, as well as the relative ease with which they can be separated and analyzed, initial research has centered mainly around this class of tar constituents. It was realized early that no listing of phenols and their physical properties existed that included enough compounds to be practicable. The purpose of this paper is to make such a compilation available.

Jan 1, 1957

By O. C. Blade

This report is one of a series made by the Bureau of Mines under a cooperative agreement with the American Petroleum Institute on the characteristics of commercial aviation gasolines. The series of Surveys is a continuation of like work conducted under aimil.ar cooperative agreements with the Coordinating Research Council, Inc. by the National. Bureau of Standards from 1940 through 1946 and by the Bureau of Mines from 1947 through 1949. A completed list of the series of surveys is given at the end of this paper.

Jan 1, 1951

By Sigmund Black

Ingersoll-Rand Research, T n c and the Lee-Norse Co. built a Bureau of Mines sponsored, special deep cutting continuous miner under this contract to study the effects of rotational speed and depth of cut on airborne respirable dust. After preliminary tests indicated and later verified that deep cutting - low rotational speed reduces airborne respirable dust, a series of underground tests were performed (9 combinations of rotational speed and depth of cut at 45° bit angle and 4" bit spacing). Additional data was obtained on specific energy, coal sizing and noise. The conclusions reached from the tests results were; a) deep cutting reduces airborne respirable dust generated and specific energy needed to cut coal., b) the greater majority of the decrease occurs in going from 1" to 2" depth of cut, c) lowering rotational speed has a particularly sizable effect of reducing the amount of dust at the operator's location, d) no significant relationship was found for either noise level or coal sizing to rotational speed or depth of cut. Recommendations include. a)) use of specific energy as an indicator of the change in dust level correlating to changes in cutting parameters, b) mine operators should acquire new deep cutting machines., since retrofitting would be selective.

Jan 1, 1977

By S. P. Sandoval

The U.S. Bureau of Mines investigated the separation of aluminum from copper dump leaching liquors using a supported liquid membrane. Aluminum was selectively transported through porous polypropylene impregnated with di (2-ethylhexyl) phosphoric acid in an aliphatic diluent. The effects of variables, such as solution composition, temperature, and extractant concentration, were measured with a three-level fractional factorial experimental design. Experimental results were used to derive equations for predicting transport rates for aluminum, iron, and copper. The major variables influencing aluminum transport were solution temperature, feed solution pH, aluminum concentration in the feed solution, and extractant concentration. Copper and iron transport rates were almost zero when aluminum transport rates were high. Measured aluminum transport rates under the best conditions of 55° C, pH 3.0, 16 g/L A13+, and 65 pct extractant solution confIrmed the predicted value of 210 f.'g/(cm2.h). Transport rates for iron and copper were less than 5 ug/(cm2.h) under these conditions. Aluminum was recovered from the stripping solutions by sparging with gaseous hydrogen chloride to crystallize aluminum chloride hexahydrate, which was calcined to alumina. Sparging crystallization regenerated the stripping acid for recycle.

Jan 1, 1989