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By Robert D. Thomson

Sheet mica is an important material in the manufacture of electronic and electrical equipment. Large quantities are consumed each year as an essential component in generators, transformers, radios, television sets, radar, electric lighting equipment, and electrical appliances. The nature, structural imperfections, and impurities determine to a great degree the usefulness of sheet mica. Proper processing and classification add greatly to its market value. This report is designed to assist producers in understanding the complexities of marketing muscovite sheet mica. ACKNOWLEDGMENTS Special acknowledgment is due S. A. Montague, of Spruce Pine Mica Co. and G. A. Purcell, mica consultant, General Services Administration, for their critical review and many helpful suggestions in the preparation of thin report. Assistance from other industry and Government representatives is acknowledged with thanks.

Jan 1, 1955

By C. E. Wyndham

The occurrences of manganese In Alabama were reported to be widely scattered over the northeastern section of the State, and these were examined before a development project was started.2/ The most promising and available showings were chosen for further investigation, which include 1 deposit in Goshen Valley, 6 in the Rock Run area, and 2 in the northern section of Calhoun County. The work was performed by the Bureau of Mines from July 29, 1949, to February 17, 1950. The work consisted of power auger drilling 69 holes 3-1/2 inches in diameter and totaling 2,548.4 linear feet. The accuracy of samples from auger drill holes in this type of deposit was determined by sinking two shafts a total depth of 68.17 feet, from which channel samples were cut. Sixteen rotary core holes totaling 1,048.7 linear feet were drilled with a 3-inch, double-tube core barrel. Twenty-two diamond core holes were drilled with a 2-1/8-inch, double-tube core barrel and NX diamond bit. In addition to the above drilling 220.8 cubic yards of soil and rock was excavated by hand from 403.9 linear feet of trenches and 69.7 feet of test pita. A total of 206 samples were taken and analyzed for manganese, iron, cobalt, nickel, and insoluble.

Jan 1, 1953

By Karl E. Starch

This Bureau of Mines report is a background study of severance taxes on mineral production. The rates, bases, and other features of State severance tax legislation as of March 1978 are presented, as are the amounts of State severance tax collections for fiscal year 1977, Some statistical comparisons between severance tax collections, total State tax collections, and total value of mineral production in the States involved are presented to portray the relative importance of severance taxes both in State tax revenue systems and in mineral industry revenues. A general discussion of the purposes and principles of taxation, the unique nature of a mining enterprise, the various types of taxes imposed on mineral production, and the character and rationale of the severance tax and its impacts on mining firms sets the severance tax in perspective. A bibliography of materials on the severance tax is included.

Jan 1, 1979

By Michael E. Henderson

The U.S. Bureau of Mines (BOM) constructed the Hydraulic Transport Research Facility (HTRF) to investigate the hydraulic parameters relating to the transport of coarse coal. To achieve these goals in a timely and efficient manner, the Bureau contracted to Boeing Services International, Inc. (BSI) the responsibility of operating the HTRF and providing technical support. This data report is a summary of the testing and data results for the period from 6 September to 9 September 1983. The testing covered herein is for coarse 2-in by 0 (minus 50 mm) Pittsburgh Seam run-of-mine (ROM) coal in a 12-in (300 mm) pipeline, at velocities ranging from 8 to 16 ft/s (2.4 to 4.9 m/s) and at concentrations ranging from 15 to 50 pct.

Jan 1, 1985

By Diana K. Schimmelpfennig

Assessment of revegetation success on mined lands is a difficult, time consuming task and has been the subject of a number of controversies. Present regulations require that both plant cover and aboveground plant biomass be measured for use in making that assessment. Of these two variables, biomass is the most time consuming to measure and requires destructive sampling, a most undesirable requirement on fragile, recently revegetated areas. On the other hand, plant cover can be estimated using the point-frame method which is relatively nondestructive. In addition, vegetation can be sampled more uniformly with the point frame and in less time if species composition measures are to be made. A study was done to evaluate the predictability of aboveground biomass production on revegetated mined sites and adjacent native prairies using plant cover estimates made with the point frame method. The predictability of biomass production by cover estimates bears on the need for both measurements in assessing revegetation success. In general, a positive, statistically, significant correlation was demonstrated between plant cover (estimated by the point frame) and aboveground biomass (estimated by the harvest method) regardless of community type (mined or native), species composition, diversity or level of biomass production. However, the latter did have their effects on the relationship and must be accounted for in any predictive equations (that is to say, the predictive equations must be considered site-specific). Considering the relationship observed between the two parameters, cover estimation may be a sufficient indicator of revegetation success, especially where time and minimization of disturbance are critical.

Jan 1, 1982

By Lincoln A. Stewart

"INTRODUCTION The First Supplemental National Defense Appropriation Act, approved August, 25,, 1941, authorized the Bureau of Mines to investigate sources of raw, material for western production and appropriated funds for that purpose. Numerous iron deposits and prospects in the Western States were investigated. Among those selected for more detailed investigation were tile Apache and Chodiski deposits in Arizona.The United States Geological Survey had examined these deposits in 1929 3/ and estimated that ""the quantity of minable ore reasonably to be expected in this locality will reach 10,000,000 long tons, but it will require prospecting by core drill to demonstrate this quantity with certainty"". C. H. Johnson, a mining engineer of the Bureau of Mines, made a preliminary examination in October 1941 and proposed exploration of the Apache deposit Canyon Creek.A trench sampling project was set up, and work at the Apache deposit commenced in November 1941. Mapping, trenching, and sampling of outcrops was completed in March 1942. Trenches were laid out at approximately 200-foot intervals for about 9,200 feet along the iron outcrop east of Canyon Creek, and channel samples were taken across the iron formation. The outcrop also was explored by trenching and sampling along a 1,900-foot outcrop on the west side of Canyon Creek.The first diamond-drilling campaign at Apache was initiated in May 1942 and continued to January 1943, when work was suspended owing to depletion of funds. Six holes spaced at approximately 500-foot intervals and, 500 feet back from the outcrop on the east side of Canyon Creek were drilled through the iron formation during this period.While this drilling was in progress, the Chediski deposit was mapped, trenched, and sampled. The trenches were spaced at intervals of approximately 800 feet along 10,000 feet of the iron-ore outcrop."

Jul 1, 1947

By Pedro Lilienfeld

This report describes a program to develop, design, fabricate and subject to environmental testing three prototype collection-sensing devices of an eventual mining-machine mounted automated monitor for the measurement of the respirable fraction of coal mine dust to determine both short-term as well as average mass concentrations over typical 8-hour shifts. The design of this instrument is based on collection by filtration and mass sensing by beta-radiation attenuation. The emphasis of this development program was to evolve a rugged, stable and reliable collection-detection head compatible with the environment to which An eventual monitor will be subjected. Laboratory testing of this prototype instrument was performed over a representative range of temperature, humidity, dust concentration and composition, shock and vibration. The results of this testing program indicated that the operation of the prototype version His compatible with these environmental conditions and that further development of this configuration into a field operational device is justified.

Jan 1, 1977

By Alfred R. Powell

In another paper the writer has described an investigation in which the forms of sulphur in coke were determined and described. Coke was found to contain four characteristic forms of sulphur- namely, ferrous sulphide, sulphates, ad- sorbed free sulphur, and sulphur held in solid solution in the carbon. While the coke is still in the oven, only two forms of sulphur are present namely, the ferrous sulphide and the sulphur in solid solution in the carbon. During the quenching, however, the sulphur of the coke is subjected to considerable oxidation, a portion of the ferrous sulphide being oxidized to free sulphur and sulphates, while the solid solution form remains unchanged. The coke, however, loses no sulphur during this process, since the free sulphur which is formed ie retained by the coke in an adsorbed form. Since this oxidation of the ferrous sulphide took place so easily, an inves- tigation was undertaken to determine whether this property could not be taken ad- vantage of in some industrial process for the desulphurization of coke. Although it is true that such a roasting process would not touch the solid-solution form of sul- phur, still the removal of the ferrous sulphide sulphur would undoubtedly benefit the coke from the standpoint of the metallurgist. This improvement in the coke would result not only from the decrease in total sulphur, but also from the large decrease in the ferrous sulphide, which is responsible for the contamination of the iron in the upper part of the blast-furnace. The de sulphurization of coke by roasting in air it a new idea, but dates back to the earliest days of coke manufacture. In 1871, Philipparts published the results of some work done by him on the de sulphurization of coke by air, as well as a review of the results of earlier investigators. In the se earlier experiments, nothing was known of the forms in which the sulphur existed in the coke, while the temperature measurements were only approximate, so that altogether the results were not very conclusive nor complete. The de sulphurisation figures given by the se early investigators generally showed a low efficiency for the process, but some extraordinary results were claimed by certain inventors. In the light of our new knowledge concerning the coke sulphur, it seemed to be important enough to warrant investigation.

Apr 1, 1923

By G. W. Birge

Twenty-eight samples, representing the Pittsburgh, Lower Kittanning, Stockton-Lewiston, Coalburg, Winifrede, Cedar Grove, Peerless, No. 2 Gas, Powellton, and Eagle beds, were carbonized by the Bureau of Mines--American Gas Association (BM-AGA) method, and yields of products and physical properties of cokes were determined. Expanding characteristics of 22 of the samples were determined in the Bureau of Mines sole-heated oven. The Kanawha County coals tested were high-volatile A bituminous in rank, with dry, mineral-matter- free fixed- carbon contents ranging from 53.9 to 66.3 percent. With few exceptions, they were chemically satisfactory for metallurgical use, and most of the coke-strength indexes were within the industrially accepted range for high-volatile blending coals.

Jan 1, 1963

Provide respiratory protection and a clean work environment for stationary or semimobile workers at minerals processing plants. Approach An Overhead Air Supply Island (OASIS) was developed which filters, conditions, and evenly disperses an envelope of clean air over a worker's head, thereby insuring reduced dust levels and a clean work environment. How It Works The concept for the OASIS derives from an earlier Bureau development of a canopy air curtain for continuous mining machines (see Technology News #21). In this application, the benefits of a reliable, self-contained, self-cleaning industrial-duty air filtration and distribution system are extended to the minerals processing field. The OASIS draws dust-laden room air into a filtration system, removing the dust and delivering clean air to a specific 16-square-foot area. It consists of: ? a self-cleaning primary filter ? a heater (cooling coil optional) ? an airflow distributor and secondary filter (combined)

Jan 1, 1985

By E. H. Burroughs, M. J. Gavin

The references in the following compilation are selected chiefly from the literature of the years 1915-1920 , though a few of the more valuable standard works published before that period have necessarily been included . References to many articles have been omitted purposely , because the material covered by them is duplicated in publications included in the bibliography . It is manifestly impossible for the Bureau of Mines either to recommend or adversely criticize the statements of the various writers , particularly as to cost and profit estimates in articles referring to American shales , but it is hoped that the investigator will use caution in considering such statements , as it is well known that much of the literature on this subject has been published for promotion purposes and is therefore over- enthusiastic . Bearing this fact in mind , the reader should be able to judge for himself the reliability or usefulness of these articles .

Sep 1, 1921

By Louis H. Berkelhamer

"INTRODUCTION In the present war, with increasing demands on foundrymen for speedy production of sound castings, the role of sand in foundries has paramount importance.Foundry sands include both molding sands and core sands. Molding sands are those used in making molds, whereas core sands include those used for ""cores"" that fill the parts of the mold intended to be openings or hollow spaces in the casting. Core sands are, as a general rule, relatively coarse-grained as compared to molding sands. Coarse-grained sands, however, are required in making molds for large castings.Owing to the intimate relationship between properties of the sand and casting defects, it is necessary (for most efficient foundry work) to keep a close check on the molding sands used and to properly select and prepare a sand for a specific job. A mold is essentially an unfired refractory composed to meet specific requirements as to strength, permeability, and resiliency. Good green strength is important in preparing and handling the mold. Low dry and hot strengths contribute to cutting and washing, whereas high strengths cause difficult shake-out, with subsequent loss of sand. When molten metal is poured into the mold: a dried skin is attained, and gases from moisture and combustibles are driven off. Excessive moisture necessary for the proper working of a sand, as well as poor venting due to low permeability, are factors responsible for producing such defects as blows and pinholing. The skin of the mold, upon contact with molten metal, first expands and later contracts; these conditions are favorable for producing scab defects. Contact with the molten metal sometimes causes the skin of the mold to sinter or fuse and may produce a sand burn on the casting. Then again, the mold may develop excessive hot strength rapidly, thereby causing a cracked casting. Experienced foundrymen can other such relationships, too numerous to be included here."

Sep 1, 1944

By Russell J. Foster

Many important materials are derived entirely or partially as byproducts of primary copper, lead, and zinc production. This U.S. Bureau of Mines report examines the collective role of byproducts with regard to the economics of domestic mineral production, and their individual significance in terms of dollar value, end uses, and strategic considerations. The study also analyzes circumstances that have affected the competitiveness and structure of the U.S. copper, lead, and zinc industries, and factors that impact byproduct availability. These factors include production capacity at smelters and refineries, process technology, changing sources and composition of ores, regulations, foreign ownership, and byproduct demand and price. Policy considerations regarding stockpiling, regulations, and research are assessed.

Jan 1, 1991

By S. L. McGill

The U.S. Bureau of Mines has determined the microwave heating rates for a suite of minerals and reagent-grade compounds. Maximum temperature achieved for the samples and the time required to reach temperature are reported. Heating rates of powdered samples are presented as a function of incident powers up to 3,000 W at 2,450 MHz. Descriptions of the microwave cavities, test cells, and a thermocouple assembly used to measure temperature in the microwave field are given. Many minerals of value heated in the microwave field, whereas host rock or gangue materials did not. In general, heating rates increased as incident power was increased. Exceptions to this were some very good (CuO, Fe304, and PbS) and very poor (CaC03 and SiO2) microwave-absorbing materials that showed negligible changes with increased power. Applications demonstrating the use of microwave energy in mineral processing that are described herewith include oxidation-reduction reactions, mineral liberation, and mercury retorting-vaporization. Microwave data on mineral heating rates will provide insight to possible chemical and mineral processing applications as well as assist in predictions of processing parameters.

Jan 1, 2010

By Theodore M. Katz, W. Stephen Brightwell, David E. LeGrande, Joseph J. Hurrell, Jane A. Lipscomb, Nancy Lessin, Lawrence R. Murphy, Michael J. Colligan, Steven L. Sauter, Richard A. Lippin

Revolutionary changes in the organization of work have far outpaced our knowledge about the implications of these changes for the quality of working life and for safety and health on the job. This gap in knowledge is one of the 21 priority areas for research under the National Occupational Research Agenda (NORA)—a framework crafted by the National Institute for Occupational Safety and Health (NIOSH) and its partners to guide research into the next decade. This report was developed under NORA as the first attempt to develop a comprehensive research agenda for investigating and reducing occupational safety and health risks associated with the changing organization of work. Research and development needs identified in the agenda include (1) improved surveillance mechanisms to better track how the organization of work is changing, (2) accelerated research on safety and health implications of the changing organization of work, (3) increased research focus on organizational interventions to protect safety and health, and (4) steps to formalize and nurture organization of work as a distinctive field in occupational safety and health.

Jan 4, 2002

By B. E. Blair

The physical properties and related geological and petrographic data for 81 rock types obtained from operating mines or selected test sites are presented in this report. Most of these rock data were obtained to supplement structural studies in underground mines; however, the data may be equally applicable to other problems where the physical properties of rock are an important factor. Stress-strain curves are presented, where available, and free medium velocities from laboratory and field measurements are compared for several rock types. Rock-type, geographical, and geo-logical indexes are included for reference relative to physical property data in this and previously published Bureau of Mines physical property reports. INTRODUCTION This report presents the physical properties of 81 rock types from 16 different projects (sections 53-68). Three previous physical property reports2 3 4/ (herein after referred to as parts I, II, and III) presented data on 244 rock types from 52 project areas. (Part I included sections 1-25, part II sections 26-36, and part III sections 37-52).

Jan 1, 1956

By G. L. Anderson

The critical importance of wire rope integrity to the mining industry has led to the creation of standards for the retirement of wire rope as well as to the development of electromagnetic devices and procedures that would allow wire ropes to be tested against these standards without destroying them, The U.S. Bureau of Mines (USBM) conducted research to evaluate these devices by measuring loss of metallic cross-sectional area and the number of wire breaks, or local faults. The intent was to define the extent to which the technique can identify degradation within the rope, e.g., broken wires, corrosion, and wear. Experimental results showed that instrument sensitivity depended on a number of factors, including rope diameter, placement of sensors, location and characteristics of flaws, rope speed, and tension on the rope. The experiments also demonstrated the importance of having an elongated recorder trace and a properly trained and experienced operator to interpret overall results. A design of a rope and test procedures for use in laboratory evaluation of instruments have been recommended by the American Society for Testing and Materials Committee E07.07.10, Wire Rope Applications. The USBM is working through this committee to develop standards for an electro-magnetic method of wire rope inspection.

Jan 1, 2010

By The Staff, Explosives Research Center

The principal activities of the Bureau of Mines Explosives Research Center from July 1, 1962, to June 30, 1963, are described briefly in part 1. Part 2 gives short abstracts of publications that appeared during fiscal year 1963; in general, the research reported in these publications antedates the report period.

Jun 24, 1964

By A. C. Fieldner

The annual reports of the research and technologic investigations conducted by the Bureau of Mines on the occurrence, properties, mining preparation, and uses of coal, of which the present report is the seventh,4/ are intended to be brief summaries of progress. They are guides to the current work and publications of the Bureau but do not replace the more complete reports published by individuals and groups of workers on specific problems. The annual reports present the results of tests, often in advance of publication in other forms, but original contributions in research are reserved for initial publication by their authors. A survey of the accomplishments of the Bureau in research and technologic work on coal during the 5 year period 1935-40 has been made available in the form of a bibliography.5/ This supplements a similar bibliography on this subject that covers the first 25 years of the Bureau, 1910-35.6/

Jan 1, 1943

By Arne Landsberg

Accessory metals, although valuable resources, present possible environmental concern in the smelting of base metals. The Bureau of Mines, U.S. Department of the Interior, has undertaken research to define the chemistry involving these metals. Arsenic in copper smelting is the first to be investigated. Roasting, the first step in many copper smelters, was chosen for initial investigation because of the potential for arsenic removal in this primary process. Simple, static-bed, vaporization experiments were devised to obtain the data in this study. Ancillary transpiration and mass spectrometry were also used to delineate conditions necessary for arsenic volatilization from a roaster feed. For nearly complete arsenic removal, a temperature of 650°-700° C, a reducing atmosphere including carbon monoxide, and a source of sulfur were found to be essential.

Jan 1, 1980