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By Thomas Mucho, Anthony Iannacchione

This marks the 100th year that the aggregate industry has been served by a national association. Of all the accomplishments this longstanding relationship has achieved, there is probably none greater than the progress made, in worker safety. Perhaps the best way to measure this success is to examine injury trends in the aggregate miner population. For example, in the first half of the 20th [ ] century, 16 quarry mining disasters (a "disaster" is an incident with five or more fatalities) claimed 157 miners between 1909 and 1952. The largest of these was the disaster at the Sandts Eddy Limestone Quarry near Allentown, Pa., on March 26, 1942, where 31 miners died of asphyxiation by fumes/explosion. Thankfully, no mining disasters have occurred in the aggregate industry since 1952. It is these kinds of information that help us characterize improvements in aggregate worker safety over the last 100 years.

Jan 1, 2003

By Morton Corn

The U. S. Federal Coal Mine Health and Safety Act of 1969 placed limits on the permissible concentration of airborne respirable coal mine dust. Evidence exists which suggests that the effects on health of respirable coal mine dust may depend on both host factors and dust properties other than concentration. Dust particle size, shape, density, specific surface area and chemical composition are among the dust parameters of interest in an epidemiological investigation of coal workers' pneumoconiosis and coal miner exposure to mine dust. The purpose of this investigation was to develop and demonstrate the feasibility of techniques to determine selected properties of respirable coal mine dust. An approved underground horizontal elutriator which samples air at 36 cfm was designed, fabricated and utilized in this study to collect respirable coal mine dust in three mines representing the Pittsburgh, Lower Freeport and Lower Kittanning coal seams. Analytical procedures for measurement of respirable dust sample particle size, density, random projected area, total surface area and chemical composition are presented. Results of analyses of three samples collected in each mine are presented. Up to five full work shifts of sampling were required to accumulate approximately five grams of respirable coal mine dust in each sample. Statistical tests were applied to determine the significance of differences between properties of dust samples collected in the same mine and between arithmetic mean values of dust properties representing three samples collected in each mine. A comparison was also made between

Jan 1, 1972

By R. A. Beall

This paper summarizes the development of a furnace for producing titanium castings. The general problem is outlined and chronological details are given on the construction and operation of four different casting furnaces, all utilizing consumable-electrode arc heating and water-cooled copper crucibles. Of the two methods of pouring, the tilt-pour technique has been more satisfactory than bottom tapping. Mold design, electrode fabrication, and deep-pool production are discussed. INTRODUCTION In the early summer of 1953 the Bureau of Mines was contacted by the Department of the Army through Watertown Arsenal to explore the possibility of conducting research on casting titanium metal. The objective of the program was "to develop a technique for producing formed castings of titanium metal not less than 40 pounds in weight and without introduction of deleterious contamination."

Jan 1, 1956

By Franklin H. Persse

The Bureau of Mines estimated reclamation costs for 13 surface coal mines in nine States west of the Missisisppi River. With the exception of the Pacific Coast coal province, at least one mine in each of the western coal provinces was studied. Cost estimates were, made using standard estimating procedures from data obtained from company records, interviews with industry personnel, and onsite observations. Estimated costs are presented in four categories which represent the four phases of mined-land reclamation: (1) Design, engineering, and overhead; (2) bond and permit fees; (3) backfilling and grading; and (4) revegetation. Estimated costs as of the first quarter of 1976 are expressed as averages and ranges in terms of per acre, per ton of coal produced, and per million Btu. Total reclamation costs ranged from $860 to $7,200 per acre, from 6 to 84 cents per ton, and from 4 to 35.3 mills per million Btu. A mine in the Northern Great Plains coal province (Region D) showed the highest per acre cost whereas mines in part of the western region of the Interior coal province (Region A) experienced the greatest per ton and per million Btu cost. The high cost of reclamation in the Western United States is reflected in the backfill in and grading category, particularly in the cost of topsoil removal and subsequent replacement as required by individual State reclamation regulations.

Jan 1, 1977

By Jianmin Qin, Raja V. Ramani, Wilson Miola

"The number of underground work entities operating under reduced dust standards in U.S. coal mines has been increasing since the start of the decade of the 80s and is currently approaching 10,000. The concern for controlling the quartz levels in airborne respirable dust in coal mine has manifested itself in several improvements in equipment selection and operation, face ventilation practices, and dust control procedures. At the same time, fundamental studies have been initiated on determining the source-sink relationships of the airborne quartz dust. The P-7 method is the prescribed method for the determination of quartz in the respirable airborne dust samples from coal mines. Questions have been raised on the reliability of the P-7 infrared spectrometry method for quartz analysis in powders. No specific method has been defined for quartz determination in bulk samples from the mine.In a recent study on the relationship between quartz in the airborne dust and that in the materials being mined, both infrared (IR) and x-ray diffraction (XRD) methods were used on a suite of samples from several coal mines. These samples encompassed airborne respirable dust samples, airborne total dust samples, the oversize fraction from the respirable samplers, ROM samples, channel samples, and chip samples from the face, roof, and floor materials. In this paper, the sample preparation and analysis procedures for the samples are discussed. The data, analysis results, and comparisons of the P-7 and XRD results are presented. The quartz percent determined for the same sample by the two methods are different. In 85% of the samples analyzed, the quartz percents determined by the XRD method are higher than those obtained by the P-7 method. However, there is a strong linear relationship between the results from the two methods. Further, the XRD method indicates an average of 20 percent more quartz than that from the P-7 method. The reasons for the differences in the results and the need for additional studies are explored.Since the enactment of the Federal Coal Mine Health and Safety Act of 1969 and the Federal Occupational Safety and Health Act of 1970, the prevalence of free silica as an occupational hazard in dusty work environments has been a matter of increasing concern. In underground coal mining, sometimes, roof, floor, clay veins and other non-coaly material must also be mined along with the coal. Mining these materials may increase the amount of quartz in the airborne dust (Pimentel and Adam, 1985; Taylor et al., 1984; Colinet et al., 1985). The problem of high quartz levels in the respirable airborne dust is widespread in continuous miner sections. In addition to the need for controlling the silica amount in mine atmosphere, a need for a sensitive, easily performed method for the determination of free silica in airborne dust samples was also recognized."

Mar 1, 1992

By Joseph J. Wallace

1. The Pittsburgh is the most important bed in Washington County from the standpoint of present production and recoverable reserves. 2. Known measured and indicated reserves in all beds, based on a minimum thickness of 14 inches and 1,800 short tons per acre-foot of coal in place, are estimated at 4,181 million short tons as of January 1, 1954. Of this total, 4,132 million short tons is in beds 28 inches and more thick. Areas in some beds were omitted from the estimate because available data relative to the bed characteristics are too meager for making an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimated reserves.

Jan 1, 1955

By R. J. Henry

This paper describing the mining practices at the Teck-Hughes mines at Kirkland Lake, Ontario, is one of a series being prepared by the United States Bureau of Mines on mining practices, methods, and costs in various mining districts. HISTORY Prospecting was begun in the neighborhood of Kirkland Lake in 1906, but staking did not take place until 1911. Gold-bearing veins were discovered by surface trenching in 1913 on the mining claims which now make up the Teck-Hughes Gold Mines (Ltd.). A small mill was erected in 1916 after the completion of some underground exploration. A transmission' line was built in 1917 to the camp to provide adequate power for a vigorous underground campaign. Also in 1917 the present management took control operations since 1916 have been continuous,' with a steady increase in production to date.

Jan 1, 1930

By G. S. Scott

The Bureau of Mines is engaged in research to assess the hazards associated with the handling, storage, and use of combustible gases, vapors, and. liquids encountered in mines and in industry. As a part of this general pro-gram, numerous limits of flammability and ignition temperatures are being investigated for a wide variety of combustible materials, and methods are being developed to minimize the explosion hazards of these combustibles. The Bureau receives numerous requests for information on the explosion hazards of specified combustible mixtures under various conditions of use. This information circular has been prepared to assist those who may have similar requests. Destined primarily for the layman with a limited technical knowledge of the subject, it considers rather briefly the numerous factors that enter into the general problem of gaseous explosions and their prevention.

Jan 1, 1951

By Steven J. Schatzel

Prior research has suggested that the source of respirable silica dust in underground coal mines is typically the immediate top or bottom lithology adjacent to the mined seam, not mineral matter bound within the mined coal bed. Geochemical analyses were applied in an effort to identify the specific source rock of respirable quartz dust in coal mines. The analyses also demonstrate the compositional changes that take place in the generation of the respirable dust fraction from parent rock material. All six mine sites were mining coal with relatively low mineral matter content, although two mines were operating in the Fire Clay coal bed which contains a persistent tonstein. Interpretations of Ca, Mg, Mn, Na, and K concentrations strongly suggest that the top strata above the mined seam is the primary source of mineral dust produced during mining. One site indicates a mixed or bottom source, possibly due to site specific conditions. Respirable dust compositional analyses suggest a direct relationship between the quantity of mineral Si and the quantity of quartz Si. A similar relationship was not found in either the top or bottom rocks adjacent to the mined seam. An apparent loss of elemental Al was noted in the respirable dust fraction when compared to potential parent rock sources. Elemental Al is present in top and bottom rock strata within illite, kaolinite, feldspar, and chlorite. A possible explanation for loss of Al in the respirable dust samples is the removal of clays and possibly chlorite minerals. It is expected that removal of this portion of the Al bearing mineral matter occurs during rock abrasion and dust transport prior to dust capture on the samplers.

Jan 1, 2009

By G. R. Fitterer, C. H. Herty

"INTRODUCTION Manufacturers and consumers of steel have come to realize during the past few years that cleanliness is of great importance in steels which must meet rigid specifications for various physical properties. Of equal importance is the consistent production of steel which is uniform in these properties. For maximum utility steels should be uniform not only from heat to heat, but also from ingot to ingot and within each ingot. In the manufacture of killed steels such as the higher carbon forging grades, uniformity as indicated by the usual chemical analysis in easy to obtain, provided that a normal top discard is taken, as is always the case in steels poured with hot—top practice. No such uniformity, however, holds true for the nonmetallic matter, which consists for the most part of the products of deoxidation of the steel.For a large tonnage of steels which go into articles manufactured by deep—drawing processes, killed steel has never been successfully applied because with the present deoxidation practice, low—carbon killed steel is almost invariably extremely dirty. To obtain the desired qualities for deep drawing, the steel is rimmed, — that is to say, deoxidized with manganese and perhaps a small amount of aluminum, — the resultant product being of high purity in the skin of the ingot, but very badly segregated at the center of the ingot, particularly in the upper—central section. This segregation necessitates a very heavy top discard, and one of the major segregates is carbon which renders the steel too hard to draw properly. If clean, low—carbon killed steel could be made successfully, much better ingot yields would be obtained than by the present rimming steel practice. Furthermore, banded structures and outside and inside seams, which are undoubtedly due in a large measure to blowholes in the ingot, are defects which are very difficult to control in rimmed steel. These defects would be minimized by clean killed steel."

Feb 1, 1931

By Alphonso Cornejo, Galen H. Clevenger

This bibliography was compiled in connection with an investigation of the Caron process for the treatment of manganese - silver ores , conducted by the T. S. Bureau of Mines in cooperation with the Netherlands East Indies Government . The object of this investigation was to develop a practicable method for treating the refractory manganese- silver ores found in these two countries . The results of the work will be published as a bulletin of the Bureau of Mines . This bibliography summarizes the available information on the subject previous to the investigative work embodied in the forthcoming bulletin, and may be useful to those metallurgists or others conducting work along this line .

Mar 1, 1923

By J. P. Powell

Records show that systematic water flooding was begun as early as 1935 in Greenwood County and in 1937 in Butler County. Water flooding on some earlier projects in Greenwood County were described in a Bureau of Mines Report of Investigation.2/ This report presents a discussion of 4 projects -2 in Butler County, 1 in Greenwood County, and 1 in Butler and Greenwood Counties. The location of these projects is shown in figure 1. The projects have been in operation 6 to 12 years and have recovered about 6.6 million barrels of additional oil from the injection of 84.7 million barrels of water. Three of the projects take advantage of the elevation of the nearby hilly terrain, and water from the treating ponds flows by gravity through the filters into the clear-water tanks. By utilizing gravity flow, fewer pumps and less electrical energy is required, resulting in more economical operation.

Jan 1, 1956

By R. D. Brown

There are techniques for separating aluminum alloys from mixed scrap, but there are no efficient ways to separate wrought aluminum from cast aluminum. This Bureau of Mines report describes a novel technique for separating mixed aluminum alloy scrap into cast and wrought aluminum alloy fractions. The technique, which uses conventional heating, fragmentizing, and screening equipment, exploits differences in the mechanical properties of cast and wrought aluminum alloys at elevated temperatures. The cast alloys become brittle at high temperatures owing to intergranular melting of regions of eutectic composition. This melting begins to occur as the solidus temperature for each alloy is reached. Solidus temperatures for casting alloys generally range from 520° to 580° C, but are above 600° C for most wrought alloys. Thus, the casting alloys are easily fragmented while the wrought alloys remain ductile in the proper temperature range. Starting with a mixture containing approximately 80 pct cast and 20 pct wrought alloys, fractions of 100 pct cast and 98 pct wrought have been produced.

Jan 1, 1985

By S. L. May

The Bureau of Mines has developed several methods for extracting tantalum and columbium (niobium) and the rare-earth compounds from ores and concentrates. A cooperative agreement was made by the Bureau with Porter Bros. Corporation of Idaho to process 200 pounds of its euxenite concentrate by methods that had been developed at the Albany, Oreg., Metallurgy Research Center. The euxenite concentrate was processed to extract and purify the valuable metals by chlorination, solvent extraction, and hydrometallurgical techniques. Chlorination was used to convert the valuable constituents into chlorides and to partly separate them. Solvent extraction techniques were used to separate the tantalum from the columbium. The rare-earth and uranium compounds were purified by hydrometallurgical methods.

Jan 1, 1959

By N. S. Raymon

As part of an interegency agreement with the Energy Research end Development Administration to develop unproved refractory materials for use in coal gasification processes, the Bureau of Mines reviewed the literature to determine the effect of steam, H2, CO, and CH4 as well as the alkali metal oxides K2O and Na2O on refractory materials. Emphasis was given to the performance of high-alumina castable and fired refractories to conditions expected in coal gasification processes. Approximately 85 references were reviewed with 40 cited in the text. The literature was found to contain little data directly applicable to the selection of refractory lining materials suitable for use under the conditions of temperature, pressure, and gas compositions expected in second generation coal gasification reactors.

Jan 1, 1976

By John H. Hild

This is a report on work done and results obtained in a minerals exploration program conducted by the Bureau of Mines on the lead-zinc deposits in the Ross Basin-Lake Como district, San Juan County, Colo., in 1948, 1949, and 1950. Four large veins--the Seven Thirty, Red Rogers, Cashier-Shorts top-Canandaigua, and Queen Anne--and several narrow spur veins were explored at relatively shallow depths with core-drill holes. Thirty-nine holes, totaling 10,491.5 feet, were drilled, and the core samples were assayed at the Bureau of Mines station at Salt Lake City, Utah.

Jan 1, 1959

By John C. Edwards

The Bureau of Mines developed a mathematical model to predict the oxygen requirements for a miner evacuating a mine. The model accounts for variations in the miner's escape speed with mine airway height, and for the empirically determined expressions for the weight-specific oxygen uptake rate for upright walking, stooped walking (duck-walking), and crawling. A Fortran computer program that is user oriented was prepared based upon the model's constitutive equations. Specific instructions for utilizing the program, as well as applications to miner evacuation from a mine, are presented.

Jan 1, 1986

By G. Asai

The Bureau of Mines has been engaged in a program to increase the utilization of chromium by providing samples to individuals and institutions requesting chromium for research investigations. This report consists of a tabulation of the disposition of chromium samples distributed from July 1953 through June 1961; 109 requests for chromium were answered by providing chromium as electrolytic plate, powder, or wrought forms. The demand for samples reached a peak in fiscal year 1959 and declined to a relatively low level in fiscal year 1961. The largest number of requests came from individuals engaged in mechanical property studies; there were also many requests from those concerned with vaporized metal and physical properties studies. Most noteworthy application for chromium was the experimental use of the radioactive form, Cr61 in radiotherapy of cancer.

Jan 1, 1964

By G. Asai

The Bureau of Mines has been engaged in a program to increase the utilization of chromium by providing samples to individuals and institutions requesting chromium for research investigations. This report consists of a tabulation of the disposition of chromium samples distributed from July 1953 through June 1961; 109 requests for chromium were answered by providing chromium as electrolytic plate, powder, or wrought forms. The demand for samples reached a peak in fiscal year 1959 and declined to a relatively low level in fiscal year 1961. The largest number of requests came from individuals engaged in mechanical property studies; there were also many requests from those concerned with vaporized metal and physical properties studies. Most noteworthy application for chromium was the experimental use of the radioactive form, Cr[51], in radiotherapy of cancer.

Jan 1, 1964

By Richard D. Hagni

The character of phosphorous-bearing minerals in the Birmingham red Iron ores and iron-bearing minerals in the Eufaula bauxite deposits in Alabama has been Intensively studied by petrographic, ore microscopic, luminescent microscopic, scanning electron microscopic, electron microprobe, and x-ray diffraction techniques. A total of 15 types of phosphorous-bearing mineral grains have been recognized in Birmingham iron ores by their characteristic sizes, shapes, and distributions. Size measurements, modal analyses, and texture analyses have permitted an estimate of potential liberation of phosphorous from the iron ores by beneficiation to be 27% In areas of previous mining and 60% in areas of current iron reserves. Fine grinding, selective flocculation, and flotation may constitute the best beneficiation technique for future research. Hematite and goethite are the most important iron minerals in Eufaula ferruginous bauxites, but pyrite, marcasite, and siderite are Important iron minerals in some varieties of ferruginous bauxite, and lepidocrocite and ilmenite occur locally in minor quantities. Although simple screening will remove the coarsest iron-bearing grains, research on the utilization of high gradient magnetic separation to reduce the amounts of iron-bearing grains is recommended.

Jan 1, 1981