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By B. W. Haynes

With the national focus on energy, the combustible fraction of urban refuse is being extensively considered as a fuel supplement for coal in the generation of heat and power. The objective of these analytical studies by the Bureau of Mines was to determine the concentration of major, minor, and trace elements in the combustible fractions collected at various locations in the Bureau's urban refuse recycling pilot plant located at College Park, Md. The samples processed through the plant were submitted by various municipalities that are considering resource recovery as an alternative to landfill or other means of disposal. Twenty-five elements were determined in samples from six geographic areas and were compared with element concentrations found in typical coal samples.

Jan 1, 1977

By Khamis Y. Haramy

This U.S. Bureau of Mines report describes the use of Bureau-developed flat and cylindrical hydraulic borehole pressure cells. A brief description of the fabrication, installation, and pressurizing equipment is given and pressurizing procedures are discussed. Theories available on evaluation of data from the flat and cylindrical pressure cells and examples of data analysis and stress evaluation are also presented.

Jan 1, 1991

By T. M. Barczak

The term "resultant load vector" is defined as the representation of the forces applied to a longwall roof support element by strata activity through a single, quantifiable measure of support resistance. The relatively complex kinematics of the shield structure prohibits determination of support resistance simply from the summation of leg forces. In the research reported in this Bureau of Mines study, the mechanics of the shield structure were evaluated, and a technique was developed whereby the resultant shield loading could be determined by instrumenting supports with pressure transducers and strain gauges to measure leg, canopy capsule, and lemniscate link forces. This technique has been laboratory tested in the Bureau's Mine Roof Simulator. Functional relationships among variables were assessed, and confidence intervals were established for prediction of the resultant load vector parameters. Resultant load measurements were taken on five instrumented shields on an active longwall face in Colorado. Results were analyzed and found to be consistent with shield mechanics and anticipated roof behavior. Benefits to be derived from this research, future efforts, and long-range goals are discussed.

Jan 1, 1986

By Edward L. McHugh

The appraisal of mineral resources of the Challis National Forest, Idaho, by the U.S. Bureau of Mines, was made so that the mineral resources of the forest could be appropriately considered in land use planning. Information from this study is intended to help the U.S. Forest Service to incorporate mineral resource data into forest plans. The study was done in conjunction with the U.S. Geological Survey, which released a companion report on the geology and mineral potential of the Challis National Forest in 1989. Mineral development activity in and under the Challis National Forest has been of great economic significance to Idaho and the United States. Since the 1960's, mines within the forest have produced mineral commodities worth more than $590 million A current (1989) commodity prices. Identified mineral resources have a gross value of about $2 billion at current prices, including 8 strategic or critical minerals. The U.S. Bureau of Mines study identified and described 723 active and inactive mineral properties within the forest. Mineral properties with identified resources were evaluated to determine their economic significance, and an assessment was made of the feasibility of mineral development. Of the 2,516,191 acres in the Challis National Forest, about 390,000 acres were classified as having mining development interest commercially important mineral production, mainly of molybdenum, gold, and silver from the Challis National Forest is likely for the foreseeable future.

Jan 1, 1991

By Forrest T. Moyer

The safety record of the metal mining and milling industries in 1965 is reviewed by the Bureau of Mines. The overall injury-frequency rate of 23.77 per million man-hours was 5 percent lower than in 1964 and was the lowest annual rate in a statistical history beginning with 1931. The injury-severity rate of 3,521 days lost per million man-hours in 1965 represented a 5-percent improvement over 1964. However, the total of 3,825 disabling work injuries comprised 61 fatal and 3,764 nonfatal injuries, one and 92 more, respectively, than in 1964. At primary nonferrous smelters, refineries, and reduction plants, the injury-frequency rate of 8.97 per million man-hours in 1965 was 13 percent lower, but the severity rate percent higher than in 1964. these plants in 1965, 4 more of 1,173 days lost per million man-hours was 17 There were 12 fatal and 971 nonfatal injuries at and 28 fewer, respectively, than in 1964.

Jan 1, 1969

By D. L. Sawyer

The Bureau of Mines studied alumina extraction from uncalcined, kao-linitic clay at temperatures from 1000 to 2500 C using 20-or 27-wt-pct-HCI concentrations and with an acid-to-clay ratio of from 0.8 to 1.4 times stoichiometric. Autogenous digestion pressures ranged from atmospheric pressure to about 900 psia. Extraction of 96 pct of the alumina was obtained by HCI leaching at temperatures and leaching times that varied from 1000 C for 120 h to 2000 C for 15 min. Hydrochloric acid stoichiometry of the reaction A1203'2Si02'2H20 + 6HCI + 2AICl3 + 2Si02 + 5H20 was studied at different temperatures and leaching times in a 750-mL tetrafluoroethylene-polymer-lined autoclave. A combination of high temperature and 20 wt pct excess HCI promoted rapid and almost quantitative extraction of alumina (99 pct in some tests). Additional Bureau data obtained with 35-mL tantalum bombs and leach-ing tests with added fluoride are also provided. At high temperatures, the addition of fluoride did not result in a significant improvement over HCI alone and was deleterious to the filtering properties of the digest residue.

Jan 1, 1985

By Zabetakis M. G.

This Bureau of Mines report presents a brief summary of the explosion trends in United States coal mines for the past 160 years. These trends show that in spite of the overall improvements in mine safety, the number of fatalities from ignitions of methane has actually increased in recent years. Suggestions are made of procedures that can be utilized to reverse this trend.

Jan 1, 1973

By Thomas A. Phillips

The Bureau of dines present, an economic evaluation of its process for the ferric chloride leaching of chalcopyrite concentrate. In this process, chalcopyrite concentrate is leached with ferric chloride solution to extract copper, which is precipitated from the solution by electrolysis while leaving sulfur in the residue. Spent liquor from electrolysis is treated with oxygen to regenerate the ferric chloride leach solution and the sulfur-laden residue is processed to recover the sulfur. A cost estimate was prepared for a plant capable of processing 600 tons of chalcopyrite concentrate per day, 330 days per year. The fixed capital cost, on an early 1.975 basis is $27,831,600 and the estimated operating cost is 9.9 cents, per pound of copper product. In comparison, the estimated operating cost of a smelter equipped with a citrate process plant to recover sulfur is about 13.6 cents per pound of copper product. No charge for chalcopyrite concentrate or credit for recovered byproducts has been included in either operating cost. The ferric chloride leach process, therefore, appears to be economically attractive.

Jan 1, 1976

By LeRoy D. Loy

The disposal of excess overburden from surface mining can be accomplished by use of a reclamation technique entitled head-of-hollow or valley fill. This report attempts to assess current valley fill regulations and practices, identifies inherent benefits and deficiencies, and develops concepts to enhance fill technology.

Jan 1, 1978

By Stanton L. Tainter

"INTRODUCTION Molybdenite, the only common mineral and ore of molybdenum, occurs wide¬-spread but is concentrated as the main ore mineral in commercial quantities in only a few known deposits. Consequently, the Government sought additional sources of the minerals as a precaution against the possible shortage of moylbdenm for war uses. Upon request by the War Production Board, the New Year’s Eve and Esperanza properties of the Amargosa Molybdenum & Copper Corp. were investigated by the Geological Survey 3/ and the bureau of Mines 4/. The Survey appraised the mineral potentialities of the deposit and prepared topographic and geologic maps, and the Bureau made a preliminary engineering examination. The deposits were previously examined by W. J. Vanderwilt, consulting engineer. It was largely due to his recommendations that interest was stimulated in the deposits.Development on the New Year’s Eve deposit indicated a small tonnage of sub marginal ore. There was little development at the Esperanza, but surface examination revealed a large volume of rock containing a little molybdenite and a trace of copper in the oxidized outcrops. Some molybdic oxide was noted suggesting that some molybdenite might have been leached from the oxidized outcrops and that the molybdenite content in the sulfide zone might be higher."

Feb 1, 1947

By Victor E. Kral

"SUMMARYFollowing a magnetometer survey on the McCoy iron deposit, a trenching and drilling program was carried out by the Bureau of Mines in August 1944.This deposit is 32.3 miles southwest of Battle Mountain in the McCoy Mining District, Lander County, Nevada, and lies on the east flank of the Fish Creek Mountains at an altitude of 5,400 feet, about 1 1/2 miles south of the gold camp of McCoy.Total production from the deposit has been 400 tons of magnetite, mined by hand and shipped to the west coast for ship's ballast.Bureau drilled two holes to a total depth of 92 feet and excavated 12 feet of trenches. Both holes were drilled in the same ore body and engineered magnetite ore 14 and 11 feet thick. Trenching was used successfully to show the lateral limits of the ore.Magnetite ore bodies were found to occur as replacements of a limestone bed in quartzite. They outcrop near and parallel to the exposure of a diorite entrusting that forms a long westward-trending ridge. Although magnetic outcrops can be traced for 5,000 feet trenching definitely proved the ore bodies to be disconnected to have little or no lateral extent beyond their outcrops. Only two ore bodies more than 10 feet thick were found; one of these is the inaccessible to and the other was drilled by the Bureau."

Jan 1, 1947

By George Markon

The rapid growth and development of the Soviet coal industry rank the U. S. S. R. with the United States among the leading coal-producing countries. The coal resources of the Soviet Union are among the largest in the world, although coal development has been hindered by the disadvantageous location of the coal deposits with respect to the major consuming centers. Although coal production in the U. S. S. R. reached a record high, the total energy output of mineral fuels in 1957 was still far below that of the United States because a significant part of Soviet coal output was lignites or lower rank coals. Although the Soviet coal industry soon may exceed that of the United States in tons produced, the energy equivalent of Soviet output will be considerably less because of the inclusion of a high percentage of lower rank coals. Energy sources in the United States also involve large quantities of oil and natural gas, whereas coal supplies most primary energy in the Soviet Union.

Jan 1, 1959

By E. G. King

This publication presents original thermal data for a typical variety of perlite and supplies basic information for use in computing energy requirements in processes for expanding perlite. Perlite has been defined by Raiston 4/ as any silicious lava containing dissolved water in sufficient amount to errand into bubbles when the material is quickly heated to a suitable point in the softening range." The uses of expanded perlite in) the construction and ceramic industries have been discussed by Ralston 4/ and King. 5/ The work described here had a dual purpose: (1) It was desired to ascertain quantitatively, using a typical variety of perlite, just how firmly the contained water is held, and (2) it was desired to obtain basic thermal data sufficient for energy-requirement calculations in processes for expanding perlite.

Jan 1, 1948

By H. E. Powell

Basic data were recorded on the decompositions that take place during thermal decomposition of siderite (FeC03). Both the naturally occurring and a synthetically prepared mineral were studied by differential thermal, thermo-gravimetric, X-ray-diffraction, and chemical (including gas) analyses. Thermal decomposition was studied in the media of dry air, moist air, dry carbon dioxide, dry helium, and dry carbon monoxide and at atmospheric and at reduced pressures. Results showed the thermal decomposition of FeC03 to be an extremely complex process, dependent on environmental factors and side reactions that cannot now be completely controlled. Therefore, full understanding of the reaction involved must depend on additional research with advanced evaluation techniques.

Jan 1, 1965

By J. M. Mutmansky, C. Lee

"Measurement of the size and elemental characteristics was performed on airborne coal mine dust samples collected by multi-stage cascade impactors as well as channel samples of the geologic materials. Size distributions were obtained using precise weighing techniques on the impactor substrates. Elemental analysis on the samples was performed by the proton-induced x-ray emission (PIXE) method, a rapid and non-destructive method of multi-element analysis.The various analyses were performed on 9 major and 21 trace elements. The results indicate the importance of intake air and shuttle car movements as sources of dust. The association of coal dust characteristics with channel samples was investigated using the coefficient of proportional similarity as a statistical measure. Results show a strong relationship between major elements and the geologic material being cut but a similar relationship between trace elements and geologic materials is not consistent.1. INTRODUCTIONThe most significant occupational disease in the coal industry is known ·as coal workers' pneumoconiosis (CW'P). While CW'P has existed for centuries, its mechanism of occurrence and association with coal dust has been well understood for only a few decades. In the 1930s, the significance of this disease led state and government officials in the USA to perform extensive epidemiological and environmental studies in the major coalfields. Study of these results plus later studies in the coal producing countries of Europe eventually led to the dust regulations that appear in the Federal Coal Mine Health and Safety Act of 1969.The impacts of the 1969 act were a productivity decline and increased production cost. Many analysts attributed this in large part to difficulties in complying with the new dust standards (Brezovic 1981). However, compliance was met in most continuous miner sections rather quickly. The remaining problem area is that of longwall mining where the procedures and layout of the minin~ system make it difficult to meet the standards."

Jan 1, 1989

By Michael S. Miller

In 1984, at the request of the Bureau of Land Management, the U.S. Bureau of Mines studied the 34,050-acre Cow Creek Wilderness Study Area (WSA) in order to evaluate its mineral resources. The WSA, located about 60 miles southeast of Havre, MT, contains sandstones, shales, clays, and coal of Cretaceous age. The Cretaceous rocks have been intruded by ultramafic diatremes. Quaternary glacial, stream, and landslide deposits overlie the older rocks. Claims are staked at five of seven sites favorable for diamonds within the WSA and at additional sites nearby. Although the ultramafic diatremes within and near the WSA contain minerals that are indicators for diamonds, no positive evidence of diamonds was found during this study. An abandoned coal mine, the Shellenberger, is inside the southwest boundary of the WSA. Possible petroleum and natural gas at depth are currently of interest; land within the WSA is leased or under lease application for oil and gas. The WSA contains subeconomic clays, zeolites, gold, silver, platinum group metals, and coal.

Jan 1, 1986

By Stephan Stecura

One of the principal objectives of the Bureau of Mines program for development of superrefractory ceramic materials is to obtain fundamental data on the physical properties of refractory oxides. Elements of particular interest to research workers in the Bureau include groups III and IV of the Periodic Table and the rare-earth group. This report contains thermal expansion and phase inversion measurements on oxides of scandium, yttrium, lanthanum and 12 lanthanide series elements (promethium and terbium omitted) up to 1,350°C, made by high-temperature X-ray diffractometer techniques. Thermal expansion values were calculated from unit cell dimensions measured at selected temperatures; with anisotropic oxides expansion was determined parallel to each major crystallographic axis. The combined random and systematic errors in the thermal expansion values are considered to be less than 3 percent of the total expansion at 500° C, and approximately 2 percent at 1,000° C, No difference in expansion coefficients was observed between heating and cooling cycles for oxides that did not undergo phase inversion. Tabular data of linear expansion, in percent, linear expansion coefficients, and graphical presentation of linear expansion as a function of temperature are presented.

Jan 1, 1961

By C. W. Owings

"PURPOSE OF REPORTMany bituminous coal-mine officials realize that coal dust presents an ever-present coal-mine explosion hazard, and that persons forced to breathe large quantities of it may be more subject to respiratory infection than persons working in less dusty atmospheres. As an outgrowth of the realization that coal dust should be allayed at its source, many mining companies have expressed the desire to install dust-allaying equipment, and in a number of mines, water or wetting solution is being applied on the cutter bars of mining machines, on mobile loaders, belts or conveyors underground, and tops of mine cars. Spraying equipment also has been installed on dumps to allay dust during dumping operations. Dust-allaying equipment has not been standardized, however, because manufacturers have found that many prospective purchasers of such equipment have different ideas. These manufacturers wish to standardize, so far as feasible, the types and placement of such equipment. Many mine officials, although interested, do not know the best or most effective methods for allaying dust.For a number of years the Bureau of Mines has advocated allaying dust by applying water or, more recently, water modified by a wetting agent on the cutter bar of mining machines and by applying water to loaded and empty mine cars in order to keep as much dust as possible from spilling onto the haulage roads. In recent years this Bureau has also advocated applying water with or without a wetting agent during mechanical loading of coal and during unloading of coal from trackless cars or buggies and from elevating conveyors. It has now become apparent that specific arrangement of pipes, hose, and nozzles should be standardized to at least some extent. It is the purpose of this report, therefore, to give in detail suggested arrangement of dust-allaying equipment in the hope that both manufacturers and mine officials will have available dust-allaying equipment with maximum efficiency to do the desired work."

Nov 1, 1945

By J. B. Janus

This report, the 22d in a series, gives analytical data showing composition and quality of tipple and delivered samples of coal collected during fiscal year 1972. This coverage lists mines located in 20 States. Ultimate analyses are given for most of the coalbeds listed. Tipple samples were collected by Bureau of Mines engineers at tipples as coal was being loaded into railroad cars or trucks. The deliveries were sampled in accordance with instructions issued by the Bureau of Mines, and the samples were analyzed in the Bureau laboratory at Pittsburgh.

Jan 1, 1973

By C. H. Riggs

This petroleum-engineering report of the Atlanta oil field in BO them Arkansas reviews reservoir conditions and pressure-production history of one of the important Smackover limestone fields in southern Arkansas. The study of the field was made and the report prepared to aid operators in this and similar fields to increase the efficiency of recovery through the application of better engineering practices. A similar study of the Magnolia field in Arkansas by Carpenter and Schroeder was the first of these reports prepared under a joint agreement between the Arkansas Oil and Can Commission and the Bureau of Mines. The increasing demands for petroleum and its products and the steadily increasing cost of discovering and developing oil field; emphasize the importance of conserving known reserves of oil and gas. In recent years vast improvements have been made in the technique of oil recovery, both by better utilization of the natural energy stored in the reservoir and by improved methods of applying external energy to the reservoir system. This report may aid in oil conservation by careful evaluation of the several factors that did or did not contribute the greater recovery in the Atlanta field and by suggesting improvements in production methods and applications.

Jan 1, 1949