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By Anthony T. Xannacchione, Luis E. Vallejo

At present, there is little knowledge concerning the shear strength of clays containing floating rock particles with concentrations from 0 to 30%. In practice, the effect of rock particles is typically disregarded in shear strength analysis The two primary reasons for this are: 1) a lack of agreement concerning the influence of rock particles on material strength, and 2) the expense and difficulty of testing day-rack mixtures with existing laboratory procedures. These factors have impeded the development of successful slope remediation design techniques far colluviums derived from resistant sedimentary rocks or spoil produced from surface mining. This study reviewed 3 1 technical papers which contain analysis of shear strengths for clay and sands with varying mixtures of rock particles. These technical papers, published over the last 40 years, are comprised of field case studies, laboratory evaluations, and theoretical analysis. Evaluation of this body of knowledge ha shown that the shear strength gradually increases with increasing percentages of floating particles in unsaturated clays.

By Steve Signer, Ed Mchugh

Recent studies by researchers from the National Institute for Occupational Safety and Health indicate that shear loading contributes significantly to failure of bolts used for rock reinforcement in coal mine roofs, Laboratory tests on 17 bolts were conducted to study the behavior of roof bolts subjected to shear loading over a range of axial bolt loads, Fourteen strain gauges were attached to each bolt to measure axial and bending loads at seven locations along its length. The instrumented bolts were grouted through two high-strength concrete blocks, and axial tension was applied to as much as 75% of yield strength. With the block interface acting as a failure plane, shear loads were applied to the blocks at a constant rate of displacement to the ultimate strength of the bolts. The tests characterized the relationship of axial bolt loads to shear forces across a rock bedding plane and measured the distribution of axial and bending strain along the length of the bolts. 'These results will improve the selection of roof reinforcement in mine areas where high shear stresses are present, thus improving the safety of miners working in these areas.

By Donald W. Mitchell

Research shows that water neutralizes the explosion hazard of coal dust when present in sufficient quantity and when intimately mixed with the dust. The quantity of water required to neutralize coal dust and coal-rock dust mixtures is about equal to the limiting moisture adsorptive capacity of the dust; the adsorptive capacity increases with increase in the fineness and volatile content of the coal. Pools of water or high atmospheric humidity do not reduce the explosion hazard. Although wetted dust is less dispersible than dry dust, poor dispersibility cannot be relied on as the sole safeguard against explosion. Dust mixtures that contain water in excess of their limiting adsorptive capacity are dispersed and ignited by severe initiation sources. Pure coal dust adsorbs water with difficulty and retains water poorly; adsorption and retention is increased by the addition of rock dust the coal; the rock dust agglutinates wetted coal and assures that incombustible is present should drying occur. Therefore, it is advantageous to rock-dust wet areas in bituminous coal and lignite mines. When coal-rock dust mixtures are wetted and subsequently dried, the explosion hazard is about the same as for dust which was not wetted.

Jan 1, 1962

By Paul S. Goodman

Volume II The purpose of this study is to explain reasons for the productivity differences in mining crews. The literature on group productivity is examined. Then a new approach to estimating productivity differences is proposed and estimated across seven different mines. The results indicate a fairly robust model in terms of explanatory power. Recommendations on how the model can be used as a managerial tool are presented.

Jan 1, 1985

By Vance G. Leak

A technique for recovering copper and steel from metallic scrap has been developed by the Bureau of Mines based on preferential melting in molten salt baths at 1,150° to 1,250° C, The molten salt, preferably barium chloride or calcium chloride, both minimizes oxidation of the metals and promotes heat transfer. Cleanest separations (0.01 percent copper remaining in iron) have been achieved by pretreatment (dipping or spraying) with sodium sulphate or sodium silicate, which alters and coats the surface of the iron to inhibit the alloying or brazing with copper. An economic evaluation of the process was carried out on six combinations of sweating media and inhibiting reagents. On the basis of the postulated model, a cost of about $0.20 per pound of copper recovered has been determined for the sweating treatment operation.

Jan 1, 1973

By James Westfield

This report covers the calendar year 1954 and has been prepared and submitted to the Congress of the United States in accordance with the provisions of Sec. 106(a) and Sec. 2l2(c) of the Federal Coal-Mine Safety Act (66 Stat. 692; 30 U.S.C. Sec. 451-483). Background The Federal Coal-Mine Inspection program was established to carry out the provisions of Public Law 49, 77th Congress, H. R. 2082, approved May 7, 1941. This act has since been amended to be known as Title I -Advisory Powers Relating to Health and Safety Conditions in Mines, under Public Law 552, 82d Congress, approved July 16, 1952, which also includes Title II -Prevention of Major Disasters in Mines. Public Law 552 is known as the Federal Coal-Mine Safety Act.

Jan 1, 1956

By W. K. Connor, O&apos

The U.S. Bureau of Mines investigated the Sheep Creek prospect in the north-central Alaska Range to evaluate the Pb, Zn, Ag, and Sn resources. The studies included field investigations, mineralogical characterization, and concentration tests. Mineralization at Sheep Creek consists of disseminated, banded, and massive pyrite, sphalerite, and galena. Tin occurs as grains of cassiterite (Sn02) in the quartz-mica matrix and within pyrite and sphalerite grains, and Ag occurs in solid solution within the galena. Three bulk surface samples and two sets of core samples were collected at the Sheep Creek prospect for this study. Gravity concentration yielded products with up to 30 pct Sn, and the best result was a product that recovered 52 pct of the Sn at a grade of 22 pct Sn. Bulk sulfide flotation yielded products that recovered up to 89 pct of the Zn, 73 pct of the Pb, and 75 pct of the Ag, but grades were relatively low; selective flotation would significantly increase the grades.

Jan 1, 1989

By S. R. Borrowman

This investigation by the Bureau of Mines was undertaken to develop information on the extractive metallurgy of thorite ores because potential ore bodies of this mineral have been found recently in Colorado, Idaho, and Montana. Basic information on thorite ore treatment that would be useful in appraising the potential of these and other domestic thorium resources was developed. The work was done mainly on thorite ore containing 3.87 percent ThO2 from the Powderhorn district, Colo., and on a composite sample containing 0.52 percent ThO2 from the Wet Mountains district, Colo. Limited tests of d corroborative nature subsequently were made on a sample containing 2.30 percent ThO2 from the Lemhi Pass area on the Idaho-Montana border.

Jan 1, 1962

By E. P. Ferrero

Crude oils from fields throughout the world are analyzed by the Bureau of Mines to determine the characteristics of the oils and their contribution to the petroleum resources of the world. Analyses are reported for 169 foreign crude oil samples from 122 oilfields in Africa, Asia, Australia, the Caribbean, Europe, North America, and South America. Tables show the geographic and geo- logic origin of the samples, names of companies that supplied the samples, annual production for the fields, general characteristics and analytical and computed data, hydrocarbon-type data, cumulative production of the larger fields, and references to sources of geological and field development information. The analyses were made by the Bureau of Mines routine method and comparisons may be made with more than 8,000 other such analyses.

Jan 1, 1972

By V. R. Spironello

The Bureau of Mines is involved in research directed toward the utilization of municipal solid waste. One of the primary objectives is the recycling of the magnetic fraction of municipal solid waste (raw refuse). This is consistent with one of the Bureau's goals, which is to minimize the requirements for mineral commodities by maximizing metals recovery from secondary domestic resources, In this investigation, cupola trials were made using combinations of refuse scrap with shredded automobile scrap under basic and acid slag practices. Furnace operating information and the behavior of alloying and tramp elements was obtained. The research showed that it is possible to utilize up to 60 percent refuse scrap in the cupola under basic practice and 30 percent under acid practice, Aluminum in refuse scrap, present in bimetallic cans, increased the recoveries of silicon and manganese charged to the cupola. Increased use of refuse scrap provided iron of lower sulfur. The alumina resulting from oxidation increased the slag volume. The aluminum and tin contents of the iron increased with increasing levels of refuse scrap in the charge. Lead was not a problem with respect to contamination of the iron. In basic practice, operation of the cupola was satisfactory since all slags were adequately fluid. In acid practice, operation became troublesome above the 45-percent level. Under both practices, the cupola iron melting rate decreased. Particulates in scrubber water and stack condensate samples contained lead, zinc, and tin, and the dust load increased. The tensile and transverse strengths of the iron produced under both practices are reported.

Jan 1, 1980

By M. J. Sapko

A moderately scaled apparatus was developed by the Bureau of Mines to determine the fire resistance characteristics of mine conveyor belts and similar type materials. The design of the apparatus was based upon data obtained in full-scale fire tests and features a radiant panel to preheat the belt and a methane-oxygen ribbon burner to ignite the sample under ventilating condi¬tions in a rectangular duct. The test method overcomes the limitations of existing laboratory-scale methods and provides a measure of both ignitability and flammability in quantitative terms. Flame propagation depended upon such variables as air velocity, ignitor heat flux, and belt width and height in the test chamber. Data are presented for nine belt materials and fire resistance ratings are proposed in terms of the flame spread rate, heat release rate, and the critical ignitor heat flux. The ratings discriminate between the fire hazard posed by different fire-resistant belts and tend to be in reasonable agreement with those obtained in full-scale fire tests.

Jan 1, 1981

By A. W. Frolli

This paper, describing the open-cut mining milling, and cyaniding methods and costs at the Yellow Aster gold mine, is one of a series being prepared by the Bureau of Mines on similar practices in the United States. It is presented primarily to show methods and costs of mining and treating low-grade gold ore on a large scale.

Jan 1, 1940

Develop tools that mine personnel can use to comply with 30 CFR,Part 47. Background The new MSHA rule, 30 CFR, Part 47 (also known as the HazCom rule), requires all mines to develop a written program to track hazardous chemicals at their sites. More specifically, the rule requires that mines list all chemicals and determine which are hazardous; develop a written Hazard Communication Program; label all containers used to store hazardous chemicals; obtain or develop Material Safety Data Sheets (MSDS) for all chemicals stored or produced; provide miners with training in working around hazardous chemicals; and make information about hazardous chemicals available to all workers. All mines with six or more employees must have complied with the new rule by September 23, 2002, and mines with five or fewer employees will have to be in compliance by March 21, 2003.

Mar 1, 2003

By H. H. Schrenk, Carlton E. Brown

"The purpose of this paper are (1) to present a broad picture of the recognized methods of measuring the various forms of atmospheric pollution; (2) to evaluate the significance of such measurements; and (3) to suggest suitable methods for obtaining comparative information on the concentration of contaminants in city air.The atmosphere (the gaseous envelope surrounding the earth) consists of a mixture of gases. These gases and their usual proportions are:4/The volume of water vapor in the atmosphere ranges from almost zero (in very cold weather) to about 5 percent arid averages about 1.2 percent.Strictly speaking, any other substance in the atmosphere or an excess of any of the substances mentioned (with the possible exception of water) is a contaminant. Needless to say, there are many contaminants in the atmosphere.In accordance with their physical state, contaminants may be classified as gaseous or particulate, and the latter may be classified as solid or liquid matter. Particulate matter, especially when dispersed in some medium such as air or some other gas, sometimes is referred to as dispersoid, and the complete system of gas and dispersoid is referred to as aerosol.All substances on the earth are potential sources of atmospheric contaminants. Combustible materials (particularly fuel for heating and power), sea water, earth or soil, metals, and animals (including man) are some of the important sources of contaminants.Ordinarily gases are produced by chemical processes, whereas dispersoids are produced by both chemical and physical processes. There are two general dispersoid-producing processes: (1) Condensation, in which molecules join to form larger units or particles, and (2) disintegration, in which large units are reduced to the particulate range (which for the purpose of this article may be considered to be from 100 microns, or 1/254 inch, down to molecular size) by such processes as crushing, grinding, abrading, and atomizing.“Condensoid"" is a convenient term for dispersoids formed by condensation, and ""disintegrasoid"" for those formed by disintegration. Solid condensoids are sometimes called ""fume,"" solid disintegrasoids ""dust,"" liquid condensoids ""fog,"" and liquid disintegrasoids ""mist.""5/"

May 1, 1942

By Michael G. Zabetakis

The spillage of liquid diethyl ether in rooms at floor level and 3 feet above the floor resulted in flammable vapor-air mixtures in the immediate vicinity of the exposed liquido The liquid temperature was found to decrease by as much as 35° C., with a resultant decrease in vaporization rate. A search of the literature yielded numerous references to unstable peroxide (residue) formed by the autoxidation of ether. Such residues appear to constitute an explosion hazard in the condensed state.

Jan 1, 1962

By William R. Barton

Anthracite has been mined from the Narragansett Basin of Rode Island and Massachusetts sporadically, and with limited success, for more than 170 years. Beginning in 1974, interest in the coal of the Basin was renewed because of increasing prices and supply uncertainties involving petroleum products. During 1974-77 the Bureau of Mines analyzed 28 samples of Basin coals and conducted washing tests on 20 of them. Results, reported herein, indicate that the coals are low-sulfur, moderate- to high-ash anthracites and semianthracites, suitable for physical preparation to a product generally containing less than 10 percent ash. Additional exploration, sampling and testing will be required to permit appraisal of the potential value of the Narragansett Basin coal resources.

Jan 1, 1977

By G. S. Scott

In the course of the Bureau of Mines investigation relative to the causes, behavior, and control of anthracite-mine fires, attention was directed toward the correlation between the temperature of oxidation and the gaseous oxidation products in the range of temperatures between 100° and 350°C4/. These tests, made on a high-grade anthracite to determine the amount of oxygen consumed and the mounts of carbon dioxide, carbon monoxide, hydrogen and methane evolved when air was passed through samples of the anthracite at various elevated temperatures, showed that the gases evolved and their relative proportions vary with temperature, constitute a means for determining the probable temperature of the anthracite, and thus permit detection of incipient heating beers dangerous fire hazard exists. As the relationships mentioned are affected somewhat by the amount of previous oxidation of the coal, it was deemed desirable to know to what extent they might vary owing to this cause. It was also considered desirable to have a means for estimating the extent of oxidation from the gas analysis, as this would permit a more accurate estimate of probable temperature. Finally, it seemed desirable to know how much the composition of coal might vary over an extended period of oxidation, since this was previously suggested5/ as a possible means for estimating the probable maximum oxidation temperature to which a sample of coal had been subjected.

Jan 1, 1940

By Robert H. Lambeth

There are no identified mineral resources in the Italian Peak RARE II areas, and there are no producing or developing mines within or adjacent to the study area. Several prospects are in RARE II area M-4945, Idaho, but none were found in the area I-1945, Montana. The Viola Mine (fig. 1, no. 15) vicinity and the Heart Mountain vicinity along the west and south borders, respectively, are being prospected. There has been no recorded production from mines within the study area, but between $2.5 million and $5.0 million worth of lead, silver, and zinc were produced in the adjacent Birch Creek district - dominantly from the Viola Mine - from 1882 to 1889 (Anderson and Wagner, 1944, p. 14). The Viola and other mines in that district are possibly, on basin-margin, carbonate-hosted, lead-silver-zinc deposits stratabound within the Devonian Jefferson Formation. Previous studies have considered them to be hydrothermal, replacement orebodies. Mineral occurrences in the Heart Mountain area are possibly black-shale hosted uranium-vanadium deposits in the Mississippian-Devonian McGowan Creek Formation or perhaps the underlying Devonian Three Forks Formation. The Jefferson and McGowan Creek Formations underlie many scattered segments of the study area. The deposits and occurrence; are not sufficiently exposed to determine tonnage and grade, but sampling indicated moderate resource potential at two properties just outside the study area, the Viola Mine and the Elkhorn Group (fig. 1, no. 33). Local residents indicated there are several thousand tons of zinc-bearing resource; at the Viola line. A 23-ft (70-m) drill hole intercept near Heart Mountain et the Elkhorn Group adjacent to the stuny area contained 0.15 percent uranium oxide

Jan 1, 1983

By R. E. Gray

[The purpose of the study is to investigate cases of subsidence over abandoned mined-out areas of the Pittsburgh Coal identified from published and unpublished sources and to determine through a consideration of the geology, topography, climate, mining activity, and evidence at ground surface, what mechanisms control subsidence .and under what circumstances it takes place. The study wan performed it two phases, the first to identify all documented incidents of subsidence in mined-out areas of the Pittsburgh coal Region; and the second, to study a particular portion of the region in detail, collecting pertinent data relative to the sites within, characterizing roil the nature of the subsidence and its economic consequences, and determining the applicability of the findings to other areas whore similar problems with the collapse of abandoned miner have been encountered.]

Jan 1, 1977

By WILLIAM F. McMURRAY, James O. Lewis

The Bureau of Mines is investigating the technology of petroleum and its products, the investigation including well-drilling methods and the transportation, treatment, and utilization of petroleum and of natural gas, with especial reference to the prevention of waste and to increased efficiencyin the development of oil and gas resources in land belonging to or controlled by the Government. During. the winter of 1912-13 the enormous waste of the gas encountered while drilling for oil in the Cushing field, Oklahoma, called forth protests from various sources, and appeal was made to the President of the United States and to the Secretary of the Interior in behalf of the landowner and of the public in general. The facts were wanted regarding the amount of waste and the technical conditions that were responsible for practices causing it. An investigation was ordered and conducted under the direct supervision of the late J. A. Holmes, the first Director of the Bureau of Mines. R. S.Blatchley was sent to investigate the amount of waste going on in the Mid-Continent flelds.s In the latter part of March, 1913, J. A. Pollard and A. G. Heggem were sent to Oklahoma to study well-drilling methods with reference to the waste of gas from wells on Indian lands and to suggest means of preventing the waste of natural gas on such lands. Pollard and Heggem decided that the mud-laden fluid process, which had been used successfully for some years in Texas, Louisiana, and California was the method that would meet the situation most efficiently and economically. The method was accordingly demonstrated in Oklahoma. In 1914 Congress provided for the employment of six oil and gas inspectors to supervise oil and gas mining operations on lands of the Five Civilized Tribes in Oklahoma and to conduct investigations with a view to the prevention of waste. Positions under this appropriation have been held by William F. McMurray, James O. Lewis, Harry D. Aggers, Ralph R. "Weed,George W. McPherson, James C. Fowler, Louis W. Courtney, and Carl H. Beal, the technical work of these men being directed "byW. A. Williams, chief of the petroleum division, Bureau of Mines. After careful and impartial investigation of conditions in Oklahoma, these men also decided that the mud-laden fluid process was the one best adapted to prevent further wastes. In 1915 laws were passed by the State of Oklahoma that provide for the conservation of natural gas and oil, authority being given to the corporation commission to make rules and regulations and to employ agents to enforce them. After hearings and investigations, the corporation commission reached substantially the same conclusions as the Federal agents regarding the importance of the wastes and the best methods of conserving the gas. Technical Papers 66a and 68b were published by the Bureau of Mines in December, 1913, and January, 1914, respectively. Technical Paper 66 deals with the mud-laden fluid process in general and No. 68 with its application in Oklahoma. The interest aroused by these publications has been so widespread that within two years the first editions have been practically exhausted. Rather than reprint these publications, it has been considered advisable to replace them with the present report, which includes the results of more recent investigations. The methods of using the mud-laden fluid are an outgrowth of the rotary drilling system, which was developed in Texas and later employed in Louisiana and California. Some of the principles of the use of mud fluid had been observed and used to a limited extent for a long time in cable-tool drilling. So far as known it was first used successfully with a circulator and cable tools in the Coalinga field, California, in 1906,Harry D. Aggers, one of the contributors to this paper, working on the well. The part of the Bureau of Mines has been to call attention to its merits and to demonstrate its practical use in fields like those of the Mid-Continent.

Jan 1, 1916