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By F. J. Wiebel

"INTRODUCTION As a result of a general survey of the iron-ore deposits of Califor¬nia, the Bessemer was one shown to offer possibilities of developing com¬mercial ore reserves. Surveying and exploring were done at the request of Congress for an investigation of raw materials for the production of steel.A wartime steel plant has been established at Fontana, San Bernardino County, and a backlog of iron-ore reserve for the maintenance of permanent steel industry on the West Coast will be of National benefit in the postwar period.W. D. McMillan, a mining engineer the Bureau of Mines, examined the property in May 1942, and it was reexamined by D. W. Butner, also of the Bureau, in October 1943. Geophysical work was done by the Bureau in 1944, and the property was explored by diamond drilling from April to August 1944 and February to SeptemberACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contri¬bution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, under the direction of Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, under the direction of R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests."

May 1, 1947

By John E. Miller

Supercompressibility factors, Fpv, were derived from experimental compressibility data for five helium-nitrogen mixtures containing from 50 to 100 pct helium. These Fpv values are required as volumetric correction factors for or if ice meter measurement of "crude helium" (helium-nitrogen) purchased by the Government in a program of helium conservation. Although compressibility measurements were made by the Burnett method (2)3 - for pressures from 100 to 3,400 psia and temperatures from 40° to 100° F, Fpv values were needed only for pressures from 400 to 2,000 psia. Consequently, values at increments of 2° F, 2 pct helium, and 10 psia were tabulated only for the required pressure range. Values for pressures outside this range can be calculated from information shown in the tables. Values for the second, third, and fourth coefficients in the equation Z = 1 + BP + CP2 + DP3 are also included.

Jan 1, 1963

By M. E. Volin

To extend or delimit the known ore reserves of the Black Wonder manganese de-posit, the Bureau of Mines undertook an exploration project consisting of trenching, underground excavation, long-hole drilling, and sampling. The mineralization is spread over 6 square miles containing numerous small individual manganese deposits. There has been only small production from some of these deposits; however, simultaneous operations from many such small deposits could contribute considerably to the production from the district. A custom mill to treat oxide ore for battery use was built near Patterson in 1942 by the General Dry Batteries Co., Inc. It operated during World War II and was removed in 1944 when the manganese mines ceased operation. Except for some small experimental shipments, there has been no activity in the district since that time.

Jan 1, 1956

These proceedings consist of an introduction, nine descriptive papers, and a summary. The first paper is an overview of the respirable dust research program, the second paper describes the Mining Enforcement and Safety Administration's proposed changes in the respirable dust enforcement program, and the third paper describes respirable dust measurement. The remaining papers, by Bureau and contractor personnel, describes methods of reducing the amount of respirable dust to which coal miners are exposed. Of the six methods of reducing exposure to respirable dust described, two are methods of preventing or reducing the amount of respirable dust raised during mining operations, two are methods of collecting or removing dust after it has been released into the mine atmosphere, 2nd two describe methods that are combinations of prevention and collecting .

Jan 1, 1977

By Nicholas G. Theofilos

The Bahamian economy weathered the worldwide recession of the last few years better than most developing countries. This was mainly owing to the ties between the tourist industry of the Bahamas and the U.S. economy. The mineral industry played a minor role in the country's economy. The chief mineral exports included an increasing amount of petroleum products horn the country?s 500,000-barrel-per-day refinery, steel pipe, salt, and aragonite. A 60,001)-barrel-per-day desulfurization facility was completed by Bahamas Oil Refinery Co. (BORCO) in Freeport. The project included vacuum gas oil desulfurization, hydrogen and sulfur recovery, steam generation, water desalinization, and offsite facilities.

Jan 1, 1980

By B. J. Moore

This Bureau of Mines publication contains analyses and related source data for 276 natural gas samples from 23 States. All samples except four were collected during calendar year 1984. Those four samples were collected earlier, but releases granting permission to publish were not received until 1984. All samples were obtained and analyzed as part of Bureau of Mines investigations of the occurrences of helium in natural gases of countries with free market economies. This survey has been conducted since 1917. The analyses published herein were made by the mass spectrometer and chromatograph. The results of these investigations are published annually to make the information available to the petroleum industry and the general public. Twenty-eight publications have presented the results of 13,957 gas analyses made prior to 1984. The first three bulletins (1-3)2 contain analyses and related source data on 5,218 gas samples collected from 1917 through 1960; these bulletins have been supplemented annually by information circulars (4-17, 19-24, 26-28) containing 8,453 analyses of samples collected since 1960.

Jan 1, 1985

By Paul S. Goodman

This report examines absenteeism and accidents. The first section provides some background information on absenteeism. The second section examines trends in absenteeism in underground coal mines over time. The third section examines causes of absenteeism. Models were examined. The first model looks at self-report reasons for absenteeism. The second examines demographic correlates of absenteeism. The third model includes demographic and attitudinal predictors of absenteeism. The next section of the report examines the effect of absenteeism on accidents. The last section contains strategies for reducing absenteeism.

Jan 1, 1985

By Corwin L. Cooper

This paper, describing; the milling and cyanidation methods and costs at the Yellow Aster gold mine, is one of a series of papers being prepared by the Bureau of Mines on bold milling practices in the United States. Acknowledgments Acknowledgment is made to the executives of the Anglo American Mining Corporation, Ltd., for permission to publish this article, and to A. W. Frolli, manager, and other members of the company staff, for assistance` in preparing the, paper.

Jan 1, 1936

By R. V. Ramani

This volume is the fourth of a four-volume final report on research carried out under a contract from the U.S. Bureau of Mines on the development of a computer simulation model for surface mine reclamation planning. The other volumes are titled as follows: Volume I: Ore Reserve Estimation, Volume II: Dragline Model, and Volume III: Mine Coordinate Generator System. The Open Pit Materials Handling Simulator (OPMHS) was first developed" in 1971 and modified and updated in 1975. The present work is an update of the 1975 version and provides a direct link between the geology and reserves system and the various activities of the mining equipment in a mining system. Also, the modeling techniques in OPMHS/2 have incorporated a flexible method for describing various equipment (shovels, trucks, belts, trains, etc.), locations, their sequence of operations, place changes, and their interactions. These features allow for studying mining equipment selection, mining method analysis and reclamation planning. This report describes the Open Pit Materials Handling Simulator Version 2 (OPMHS/2). The report details the program features, operation, and application. Through an extensive set of appendices, the data input sequence, input variable definitions, sample data listing and program output are presented in detail.

Jan 1, 1985

By V. H. Gottschalk

Among the procedures developed by the Germans for providing the tonnage of iron powder needed to make rotating bands for artillery shells is the use of a ceramic tunnel kiln, not only for finishing the reduction of centrifugal powders but also for making so-called "brickyard sponge iron," which, after crushing and grinding, seems to yield a product suitable for powder-metallur- gical purposes. The final report issued jointly by the German Powder-Metallurgical Society (DPG) and the Chemical-Metallurgical Branch of the Research Depart- ment of the Metallgesellschaft, Inc. (ZFC of MG) gives the available details of this procedure, which may be regarded as a further development of the process in commercial use since 1911 at a ceramic plant in Hoeganaes, Sweden. The Bureau of Mines' wartime development of the Hoeganaes process also cul- minated in the adaptation of ceramic tunnel kilns for carrying out the solid- carbon reduction of iron ores, and comparison with the German technique should further advance the art. This information circular is issued as a supplement to Bureau of Mines reports of investigations Nos. 3819,2 3822, 3841,2 and 4271, on brick- yard sponge iron and is based on four German reports entitled "Making Iron. Powder in the Tunnel Kiln," translated from FIAT microfilm reel H-46, frames 9190-9209, 9280-9299, 9339-9357, and 9377-9384 (PB L 70042), which represent the four original research reports, Nos. 2005, 2008, 2010, and 2012, respec- tively, of the Metallgesellschaft, Inc.

Aug 1, 1948

By P. M. Ambrose, C. Travis Anderson, Cresap Moss, R. S. Dean

"MANGANESE METALMethods of PreparationMethods of preparing the manganese metal that has been used in chemical and metallurgical investigations have passed through a cycle. Most of the investigations made before the turn of the century used Moissan's pyrophoric manganese. 5/ This material was made by electrolysis into a mercury cathode and distillation in vacuo. It was essentially a pure material, and investigations in which it was employed (with proper precautions against oxida¬tion) led to accurate results concerning the intrinsic behavior of metallic manganese.An early investigation of the properties of ""Manganese-by-Mercury"" was made by M. Guntz. 6/ He prepared manganese by electrolysis of a concentrated MnCl2 solution with a mercury cathode. The manganese amalgam was pressed through chamois and distilled in vacuo (2 to 3 cm. of mercury) at 200°0., slowly rising to 250°0. Guntz recognized especially the decreased reactivity of manganese with increased temperature of mercury distillation. The most careful and com¬prehensive study of manganese made by this method is that of Kuh 7/ whose work unfortunately was never published in an accessible journal.Royce and Kahlenberg 8/ studied the electrode potential of manganese made by this method."

Nov 1, 1939

By Clinton C. Knox

Attention of mine operators and engineers in the Picher zinc-lead field has been drawn increasingly in recent years to marginal ore deposits lying at greater than normal depth below surface in the marked structural depressions known as the Miami and Bendelari troughs. Not only mining but prospect and development drilling is relatively costly in the bottoms of the structural depressions known as the. Miami and Bendelari troughs which cross the center of the Picher field. Nevertheless, operations by various mining companies in recent years have shown that no insuperable problems exist, and with the gradual lowering of grade cut-offs throughout the field, certain potential deep-ore areas, previously only partly explored seemed worthy of further investigation. Some such areas were called to the attention of Bureau of Mines engineers by lease holders and operators, while others were noted in the course of Bureau's systematic investigation of Tri-State ore reserves. The writer was assigned to make a study of. those possible "trough extensions," in the course of which all available nine maps, drill logs, and prior reports were assembled. Subsequently 41 churn drill holes were bored by the Bureau in the periods October 1944 to May 1945 and October 1946 to April 1947. The general area under investigation this project is indicated on figure 1, which likewise shows its relation to nearby towns, roads, and railroads. The location of individual deposits included in the report is indicated more clearly on figure 3. Minable ore was found in only two holes, and the structural information procured by drilling was less encouraging than anticipated. This report, however, presents all factual data obtained, in the belief that they may be useful in subsequent prospecting and development projects in the areas investigated. There are also set forth some of the stratigraphic data relative to the Picher field ns a whole and the Miami and Bendelari troughs which were assembled in the preliminary investigation of this project.

Jan 1, 1949

By F. Keith Shelton

"INTRODUCTION Cobalt is an essential metal in the normal industrial ac¬tivity of the United States. Being an important constituent of high-speed steels and other cutting-tool materials, it becomes of critically essential importance during periods of national emergency. 3/ The Presidential order of December 20, 1940, included cobalt among other essential commodities that could be exported only under license. The Executive order 4/ listed cobalt metal, cobalt oxide, and alloys containing more than 5 per¬cent cobalt as being within the licensing requirements.There was no domestic marketed production of, cobalt products from 1931 until 1940 when the Pyrites Co. 5/ produced some cobalt oxide. The major portion of the domestic cobalt requirements has been obtained from Northern Rhodesia, the Belgian Congo, and French Morocco. 6/ The uncertainty of sea transportation from those sources of supply demanded that steps be taken to obtain from domestic raw materials an adequate supply of cobalt for use in the materials required for production of indispensable machined war metal products. In connection with the national policy for attaining self-sufficiency of strategic and critical materials, the Bureau of Mines, Boulder City, Nev., Experiment Station initiated studies to recover cobalt from the low-grade oxidized cobalt deposits in the Goodsprings district, Nevada. Hewett 7/ reported occurrence of cobalt specifically in the Blue Jay, Columbia, Copper Chief, and Highline mines and generally over a widespread area in the district."

Jan 1, 1946

By N. Kumar Kittusamy

ALTHOUGH MANYSTUDIES HAVE SHOWN an association between operating heavy construction equipment and symptoms of musculoskeletal disorders (MSDs), little research has been performed that systematically characterizes the exposure of operating engineers to ergonomic hazards. This study evaluated: 1) vibration at the seat/operator interface;2) transmissibility of vibration in the Z-axis; 3) psychophysical ratings of vibration level and vibration discomfort; and 4) postural requirements of the job. Results indicate that the digging operation had higher levels of total weighted acceleration than high- or low-idling conditions. Transmissibility data showed that the seat amplified vibration, particularly in the lower frequencies. Seats demonstrated that they may not be sufficient in protecting operators from long-term effects of vibration exposure. High positive correlation was found among subjective ratings (vibration discomfort and vibration level), but moderate positive correlation was found between subjective ratings and quantitative vibration levels. Postural evaluations revealed that the operators were required to assume awkward postures of the neck, shoulder and trunk while performing their jobs. Work-related injuries and illnesses pose a continuing threat to the health and well-being of American workers. The construction industry has been historically recognized as having higher rates of fatality, injury and illness than other industries (McVittie285+; BLS). In 1994, an estimated 218,800 lost-work-day injuries were reported in the construction industry (BLS). Construction also had the second-highest incidence rate for sprains and strains. Although the industry has made progress since then, injuries and illnesses, including MSDs, continue to because for concern.

Crystalline silica is the scientific name for a group of minerals composed of silicon and oxygen. The term crystalline refers to the fact that the oxygen and silicon atoms are arranged in a three-dimensional repeating pattern. This group of minerals has shaped human history since the beginning of civilization. From the sand used for making glass to the piezoelectric quartz crystals used in advanced communication systems, crystalline silica has been a part of our technological development. Crystalline silica's pervasiveness in our technology is matched only by its abundance in nature. It's found in samples from every geologic era and from every location around the globe. Scientists have known for decades that prolonged and excessive exposure to crystalline silica dust in mining environments can cause silicosis, a noncancerous lung disease. During the 1980's, studies were conducted that suggested that crystalline silica also was a carcinogen. As a result of these findings, crystalline silica has been regulated under the Occupational Safety and Health Administration's (OSHA) Hazard Communication Standard (HCS). Under HCS, OSHA regulated businesses that use materials containing 0.1 or more crystalline silica must follow Federal guidelines concerning hazard communication and worker training. Although the HCS does not require that samples be analyzed for crystalline silica, mineral suppliers or OSHA-regulated businesses may choose to do so if they wish to show that they are exempt from the requirements of HCS. Because crystalline silica is an extremely common mineral and the HCS will affect many mineral commodities, it is important then, that there be as clear an understanding as possible of what is and what is not crystalline silica, and where it is found and used, and how it is qualitatively and quantitatively identified. This primer is an attempt to accomplish this in as nontechnical a manner as possible. This primer will examine crystalline silica. Part I will describe, in nonscientific terms, what crystalline silica is and how we come in contact with it. Part" will discuss the regulatory decisions that have created new interest in this ancient and widespread substance and will present a nontechnical overview of the techniques used to measure crystalline silica. Because this primer is meant to be a starting point for anyone interested in learning more about crystalline silica, a list of selected readings and other resources is included. The detailed glossary, which defines many terms that are beyond the scope of this publication, is designed to help the reader move from this presentation to a more technical one, the inevitable next step.

Jan 1, 1992

By Stephen C. Tadolini, Peter (Yunqing) Zhang

A unique circumstance created by monitoring a pre-driven longwall recovery room permitted measuring the stresses of a coal pillar throughout its entire life cycle in less than a week. A fender pillar, created in approximately the middle of a longwall panel at a depth of 650 ft, transformed from a solid barrier pillar - to a yielding pillar - to a residual pillar as 3 ft slices were methodically removed with the longwall shearer. The complete transformation, or life cycle, took place in less than 12 hours. The stresses were quickly transferred from the pillar onto the standing pumpable concrete supports and into the outby pillars. Roof to floor closure measurements, combined with the timing of the pillar behavior, provides a detailed look at the uncontrollable convergence of underground mine openings. Pillars remain the most important form of “primary support” and understanding these life cycles is vital for safe and efficient mine design, in both room and pillar and longwall panel extractions.

By S. D. Cramer

Corrosion research is being conducted by the Federal Bureau of Mines to determine suitable construction materials for geothermal resource recovery plants. As part of this research, the corrosion resistance of 31 iron-nickel-, aluminum-, copper-, titanium-, and molybdenum-base alloys was characterized and evaluated in laboratory corrosion studies in low-and high-salinity geobrines representative of those found in the Imperial Valley, Calif. General, crevice, pitting, weld, and stress corrosion were measured at 105° and 232° C in deaerated brines and brines containing dissolved 02, C02, and CH4 General corrosion rates in deaerated brines at 105° and 232° C were usually below 5 mpy for the alloys tested except carbon steel, the low-alloy steels, Monel 400, 70-30 cupronickel, and the aluminum-base alloys. Dissolving carbon dioxide and methane in the brines at 2320 did not markedly alter these results. However, the introduction of oxygen, which can enter the brine during process operations, seriously degraded the corrosion resistance of many alloys by increasing the incidence of stress corrosion cracking, crevice corrosion and, except for the titanium-base alloys, pitting. In deaerated brine at 2320 C, the general corrosion rates for carbon steel and the low-alloy steels were relatively unaffected by pH in the range of 6.1 to 3.0. However, general corrosion rates increased sharply below pH 3.0. In deaerated brine at 232° C, welds in several iron-, nickel-, and titanium-base alloys corroded at rates comparable to the general corrosion rates of the alloys, but the addition of oxygen to the brine increased corrosion rates for welds in Inconel 625 and E-Brite 26-1. Alloys exhibiting good corrosion resistance in the deaerated Salton Sea KGRA-type brine at 232° C were E-Brite 26-1, Inconel 625, Hastelloy S, Hastelloy G, Hastelloy C-276, TiCode-12, Ti-0.2Pd, Ti-2Ni, Ti-1.7W, and TZM. The alloys most resistant to corrosion in oxygenated Salton Sea KGRA-type brine at 232° C were the titanium-base alloys. These alloys appear the most suitable for use in the construction of geothermal resource recovery plants. Carbon steel and the low-alloy steels are unsatisfactory for high-temperature, high-salinity brines and alternative low-cost materials with improved corrosion resistance should be sought.

Jan 1, 1980

By E. J. Babcock, W. W. Odell

The Bureau of Mines since its establishment has always taken an active interest in the utilization of lignite and in the development of the lignite dep'osits of the United States. Extensive lignite fields occur in the west central States, notably in North Dakota, Montana, Wyoming, Colorado, and Texas; there are smaller areas in several other States, some of which are widely separated. The total area of the deposits and the total amount of lignite in these several districts are so enormous that the economic value is seldom recognized. To the people of ·the west and west central regions, however, the larger utilization of lignite, in whatever form it may be, is of fundamental importance, and any new methods or uses that promise to open these great lignite fields for more general and more efficient use deserve careful study. Although these lignite deposits underlie areas of thousands of square miles, their development and general utilization has been rather slow. This is no doubt partly because many of the districts are not thickly settled or highly developed in manufacturing industries, but is largely because lignites, from their peculiar physical and chemical characteristics, are low-grade fuels. Most of the lignites in these areas are imperfectly developed coals; many have a more or less woody structure; some belong to the brown-coal type; and others are darker, denser, and more homogeneous, approaching subbituminous coal. The people living in the regions in which these vast deposits occur, especially in the west central part of the United States, are vitally interested in every effort toward bettering lignite as fuel and aiding its wider utilization.

Jan 1, 1923

By Dennis R. Dolinar, Gabriel S. Esterhuizen

In this National Institute for Occupational Safety and Health (NIOSH) investigation, numerical modeling is used to evaluate the degree the pillar strength is increased with a rectangular pillar over a square pillar. Three-dimensional models are developed with pillar sizes and geometries typical of underground limestone mines in the United States. Physical properties for the models are based on geotechnical surveys of nearly 30 underground limestone mines. To examine the effects of pillar length on pillar strength with the modeling, a parametric study was conducted where the pillar width was held constant while the length and height were varied resulting in width-to-height ratios ranging from 0.5 to 1.5 and width to length ratios ranging from 1 to 6. There are two aspects to pillar strength and failure. At relatively low stresses, pillars can fail as a result of geologic structure. At greater depths and sufficient extraction ratios, the pillars can also fail as a result of the vertical stresses exceeding the pillar strength. The effects of increasing pillar length regarding both strength aspects are presented in this study. Equations were developed for the increase in pillar strength with both height and length based on the model results. The results from these equations were compared to those from previously developed empirical equations for rectangular pillars. For the more slender limestone pillars with a width-to-height ratio below one, there is little increase in pillar strength for length-to-width ratios above 2 and almost no increase with length for a width-to-height ratio of 0.5. Only with the more squat pillars is there a significant improvement in strength with length. The gain in pillar strength with length for the pillars is explained by the change in the ratio of the area of the pillar affected by the ends to the area of the pillar. For the squattest pillar, the change in strength is also affected by an increase in pillar confinement along the central length of the pillar as the pillar transitions from a square to a long rectangular pillar. With geologic structure, added pillar length can significantly improve the pillar strength, depending on the strike of that structure with respect to the long pillar axis.

By J. P. Powell

Since the beginning of waterflooding in the Midcontinent area, the Bureau of Mines has published many reports3-6/ describing in detail the results obtained on individual waterflooding projects in the area. These are intended as guides for operators in the selection of well-spacing, water-treating, and other techniques, as well as an indication of the results being obtained in waterflooding in various areas, fields, and horizons. In addition, Bureau personnel has arranged a tour of selected waterflooding projects each year for the past several years so that actual operating conditions may be observed and an additional opportunity provided for exchanging information. Each of these tours has been supplemented by a published

Jan 1, 1959