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By Irving Hartmann

The fire end explosion hazard of excessive coal-dust deposits in mines has been recognized for many years, and important measures have been developed for reducing dust formation and to alley loose dust near its source. Nevertheless, in the course of normal mining it has been estimated that 1 to 3 percent (in some thin, friable seams up to 10 percent) of the total coal mined is reduced to dust of through-20-mesh fineness. In highly mechanized, continuous mining operations the production of fines is even greater. Most dust is trapped near its point of origin and removed from the mine, but large quantities are transported by the air current and by haulage into entries, where the greatest proportion settles on the floor and the balance on the rib and roof surfaces. The latter is generally finer in particle size than the floor dust; this, coupled with its more advantageous position for dispersion, makes the rib-roof dust (also to be referred to as overhead dust) a greater potential explosion hazard.

Jan 1, 1954

By Irving Hartmann

The Bureau of Minas has been charged by the Congress with the responsibility for administrating the provisions of the Federal Coal-Mine Safety Act. One of the important duties of bureau inspectors under this act is to determine whether proper measures are taken to prevent mine explosions, which in moat miner includes Judea adequate rock dusting The investigation made after the explosion in Orient No. 2 mine, December 21, 1951, showed that much information is lacking on the adequacy of current rock-dusting and duet-sampling practices in the United States. To obtain such information, an intensive sampling survey was conducted by the Bureau in an Indiana coal mine. This paper summarizes the more Important findings from this survey, describes special samplings at several Pennsylvania coal miners, and discusses related studies in the Bureau's Experimental coal mine.

Jan 1, 1954

By K. B. Lindsey

Geologically, the Williston Basin is a large structural depression of sedimentary rock in Montana, North Dakota, and South Dakota and Manitoba and Saskatchewan, Canada. The approximate It-mite of the basin are shown on figure 1; it is roughly circular with a diameter of about 400 miles and contains approximately 120,000 square miles. Although the petroleum potentialities in this area had long been recognized, it had not been vigorously prospected by the petroleum industry because of its geographic location, rigorous winters, depths to possibly productive zones, difficult geological problems, and the fact that more seemingly favorable areas were available for prospecting. With the discovery of oil near Edmonton, Alberta, in the prolific Devonian reefs, an incentive was given to explore for oil in the southeast extension of the same sedimentary trough, the Williston Basin. The Virden field discovery in southwestern Manitoba in January 1951 was a direct result of this southeastward movement. Discovery of this shallow field was followed soon after by discovery of' deep production on the Nesson anticline in North Dakota at Clarence Iverson No. 1 well. North Dakota then became the twenty-seventh petroleum-producing State.

Jan 1, 1954

By E. J. Gleim

For many years mining men have sought for a portable device that would be direct reading and permit more positive detection of methane than was possible with flame safety lamps, which depended so largely on the training, skill, and personal ability of the user. Through the years, after the discovery that methane contributed to many mine explosions, considerable effort and large sums of money have been expended in searching for and developing instruments that would be practical, and, at the same time, reliable and safe to use. Very early in the history of the Bureau of Mines, some of its engineers were unsuccessful, after many trials, in attempts to develop such an instrument. Commercial firms, however, persisted in research until today a number of instruments are on the market that have proved to be practical in coal-mine service. It is hoped, however, that further research will bring about improvements in accuracy and other desirable features. BUREAU OF MINES STANDARD FOR METHANE DETECTORS The Bureau of Mines recognized the need for establishing minimum requirements on which to base official approval of suitable Instruments. This standard was prepared as Schedule 8. It was revised before being issued in printed form. The revision was published as Schedule 8A in 1920 and was revised on two other occasions. The present edition, known as Schedule BC, was issued October 31, 1935.

Jan 1, 1954

By E. J. Gleim

The construction of explosion-proof electric mine equipment for operation in gassy coal mines of the United States was begun as early as 1903. In 1.906, similar equipment with special protective devices was built for export. An investigation of explosion-proof motors was conducted by the United States Bureau of Mines during 1910 and 1911. In other words, this was among the first efforts of the Bureau directed toward the saving of life and property subsequent to its establishment by act of Congress in 1910. In these early motors, those with special devices for relief of explosion pressures predominated. At that time it was generally considered that, by providing for pressure relief, the enclosures could be made lighter in weight because of the lower explosion pressures developed within.

Jan 1, 1954

By H. A. Johansen

Recent advances in the metallurgy of chromium have enabled this metal to begin to take its place among the refractory metals. Considerable work is being done on the development of high-temperature alloys containing high percentages of chromium.1/2/ In spite of the relatively large amount of work done on these alloys, little is known of the properties of the pure metal. Information in the literature concerning the tensile properties of pure chromium metal is quite scant. This deficiency maybe explained by the great difficulty of preparing test specimens from such a brittle material, resulting in many losses in each phase of the specimen preparation and testing procedure.

Jan 1, 1954

By K. K. Kelley

Despite the wide interest in titanium and its compounds, no heat and free-energy-of-formation values for titanates (that is, compounds formed from titania and other metal oxides) have been available heretofore except for ilmenite (FeTi03). Such data are needed for understanding and developing processes for producing titania and titanium tetrachloride from ores (and possibly slags) and in connection with ceramic usage of titania. This paper reports experimental measurements of the heats of formation at ordinary temperature of 11 titanates-ilmenite, perovskite, barium metatinate, strontium metatitanate, barium-strontium metatitanate, barium orthotitanate, strontium orthotitanate, barium-strontium othotitanate, geikielite, magnesium-titanium spinel, and magnesium dititanate. The experimental method was solution calorimetry. The solution calorimeter was operated at 73.7°C. and used a strong hydrofluoric-hydrochloric acid mixture as the calorimetric fluid and reaction medium.

Jan 1, 1954

By H. C. Hamontre

The liquid-level gage described in this report is an instrument designed to locate liquid levels in wells rapidly and accurately and, with auxiliary equipment described, to follow moving liquid levels automatically. The depth at which the instrument makes contact with the liquid in a well is indicated at the surface by a depth meter on the cable to which the instrument is attached. When the gage is used to follow a surging moving level, the liquid depth is indicated continuously at the surface. This report contains a description and illustrations of the gage and outlines the operating procedures. The instrument is 1-3/4 inches in diameter and approximately 6 feet in length and may be operated through 2-inch tubing. The gage consists essentially of a float that moves upward with respect to the rest of the assembly, causing a change in the flow of electric current from the surface when the liquid level is reached. The instrument has been tested under a variety of conditions and has been found to be sensitive to changes in liquid level of 1/2 inch. Its accuracy is limited principally by the accuracy of the wire-line depth indicator used. It is not affected by pressure or temperature, and it can be run in open hole or under pressure through a lubricator. It employs only one electric circuit and can be run on an Amergraph single-conductor cable (type 1-H-0) ,

Jan 1, 1954

By S. M. Runke

An earlier Bureau of Mines report4/ reviewed and summarized all reports of investigations dealing with the coarse grained pegmatites of the Black Hills of South Dakota to dune 1951. It was proposed, and the hope was expressed in this report, that future progress in the development of the technology of the mining and beneficiation of the pegmatite deposits would be rapid enough to make it possible to issue annual progress reports. Although notable progress has been made in the treatment of pegmatite material, it has not been rapid enough to justify annual reports

Jan 1, 1954

By W. A. Haley

This is the second of a series of publications that describes the progress of mechanical longwall coal mining in the United States in which a German coal planer was employed.3/ Details of the equipment, a description of its operation, and the results obtained in mining the experimental panel were published in the preceding report. Experimental mining with the planer in the first panel showed an improvement in performance over conventional mining methods at the coal company's Stotesbury 11 mine. The work, which was begun on an experimental basis, soon proved successful, and the coal company purchased the equipment for continued use. Two panels, adjacent to the first, were developed and mined with the planer. Each of these panels was shorter than the preceding one because water seepage from a surface creek limited development. On completion of mining in the third panel, the planer equipment was moved by the cooperating company to a nearby mine operated in the same coal bed where a large area of coal suitable for planer mining is available.

Jan 1, 1954

By R. G. Nelson

The mechanical properties of low-hafnium, arc-melted, Kroll-process zirconium are presented. The effect of temperature on the ultimate strength, yield strength, proportional limit, elongation, hardness, Young's modulus, electrical resistivity, and impact strength are shown, The effects of cold work and annealing on the tensile properties, bend radius, and formability, as determined by cupping tests, are also given, Tensile properties are compared, in part, to those obtained on earlier graphite-melted zirconium and on crystal-bar zirconium. INTRODUCTION The commercial production of high-purity, low-hafnium bearing zirconium has been achieved, and this metal is becoming available for industrial use. However, there is little published information regarding the physical and mechanical properties of this product; and, since there have been many improvements in the production and arc-melting techniques of zirconium in the past 3 years, it was considered advisable to present the properties of the vastly improved zirconium representative of current production.

Jan 1, 1954

By V. A. Nieberlein

The purpose of this investigation is to determine the reserves of columbium (niobium) minerals in Arkansas and to develop metallurgical methods for concentrating the minerals and extracting the metal. The columbium resources of central Arkansas were explored by drilling and trenching, and a number of samples were taken. On the basis of this exploration the known reserves of the metal were estimated to be over 78,000,000 pounds. The reserves could possibly be extended by additional exploration to 150,000,000 pounds.

Jan 1, 1954

By W. A. Cole

This report covers the preliminary phase of an investigation of some clays and shales and other materials in North and South Dakota to determine the feasibility of lightweight -aggregate manufacture in the two States. The background of the light - weight -aggregate industry, on a national basis, and results of preliminary laboratory testing of samples of North and South Dakota clays and shales from various localities are presented herein. The countrywide search for lightweight aggregates was necessitated toward the end of the 19th century by the change in building design from thick, heavy, load- bearing walls to a framework of structural steel .beams and columns with thin walls, followed shortly by the use of reinforced concrete and structural concrete as materials for the load-supporting frame. Ordinary concrete, with sand and gravel aggregate, weighs about 150 pounds to the cubic foot. A lighter concrete was needed to relieve the dead load and make it possible to construct higher buildings or add stories to existing buildings.

Jan 1, 1954

By O. C. Blade

This report on the properties of motor fuels sold through service stations in the United States was made in accordance with a cooperative agreement between the American Petroleum Institute and the Bureau of Mines of the United States Department of the Interior. By agreement with the American Petroleum Institute, identification of the items is confidential. It presents analytical data for 4,680 samples, representing the products of 130 companies. The samples were collected during December 1953 and January and February 1954. As in previous surveys, the gasolines covered by this survey include those from both large and small suppliers. The data were obtained by laboratories of various refiners, motor manufacturers, and chemical companies and submitted to the Bureau of Mines for compilation. A list of the National Motor-Gasoline Survey reports published during the past ten years is given on page 5.

Jan 1, 1954

By S. M. Runke

An ever-increasing demand for beryllium and beryllium alloys has directed attention to the milling of low-grade domestic deposits as a possible means of supplying part of the Nation's ore requirements. The United States generally produces less than 10 percent of its annual supply. For example, new supply in 1953 was estimated at about 9,250 tons, of which the United States imported 8,500 tons. Domestic production was only 750 tons.2/ Since record high prices for beryl in 1952 and 1953 did not greatly increase domestic product ion, the United States must develop mechanical beneficiation processes to use low-grade deposits and reduce dependence on foreign sources

Jan 1, 1954

By Joseph J. Wallace

The 1952 Annual Report of the West Virginia Department of Mines lists seven beds that are being mined in Mingo County, of which the Cedar Grove is the most important. The Cedar Grove, Alma, and Coalburg contain the largest remaining known reserves. 2. Known measured and indicated reserves in all beds, based on a minimum thickness of 14 inches and 1,800 tons per acre-foot of coal in place, are estimated at 3,007 million short tons as of January 1, 1953. Of this total, 2,396 million short tons is in beds 28 inches and more thick. Areas in each bed 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, 1954

By J. W. Miller

This report deals with upgrading of the coal reserves of Raleigh County, VI. Va., to metallurgical standards. The data on samples herein correctly show the characteristics of the bed at the point where sampled and are used to indicate the general quality of the bed in the county. The principal results and conclusions are: 1. Raleigh County contains large reserves of high-quality, high-, medium-, and low-volatile coals. 2. The principal beds from which an increased amount of coal is expected to be mined in the future are: The Eagle, Powellton, No. 5 Block, Hernshaw, Fire Creek, and Pocahontas No.6.

Jan 1, 1954

By H. L. Riley

Cleaning and handling of fine coal are generally conceded to be more difficult problems than preparation of the coarser sizes. Increased mechanization in the coal-mining industry has, in general, resulted in an increased percentage of the fine sizes in the total coal mined. If the coal fines are cleaned by wet methods, the minus-1/16-inch square-mesh particles cause most of the sludge and slurry problems encountered in preparing wet coal. Equipment that separates coal from refuse on the basis of specific gravity is not efficient on sizes that, because of their fineness, do not follow the same laws of hindered settling as the larger particles. Probably the best solution of fine-coal cleaning problems is to use other methods, such as flotation, that utilize other physical characteristics than those determining hindered-settling ratios. Regarding the type of flotation known as the Elmore vacuum-flotation process there has been a scarcity of data and information available in this country. An investigation has therefore been made to obtain additional date and information on this process under laboratory conditions. During this investigation an effort has been made to evaluate the relative efficiencies of vacuum and mechanical laboratory froth flotation cells. The investigation included float-and-sink, screen-sizing, and flotation tests on 2 different samples of 14-mesh to 0 raw coal and an a sample of slurry from the settling-tank overflow of a typical washer. One raw-coal sample was obtained from the American bed and represented a type of coal that is relatively easy to clean. The other raw-coal sample was from the Mary lee bed and represented a type considered difficult to clean.

Jan 1, 1954

By R. J. Hundhausen

The continued worldwide shortage and strategic value of nickel place great importance upon the continued development and exploitation of new sources of nickel in the United States, The deposits of nickel-bearing minerals in Oregon and Washington have attracted considerable attention, particularly since the Hanna Development Co. has engaged in development work aimed at producing ferronickel from the Nickel Mountain deposit, near Riddle, Douglas County, Greg. The Red Flats nickel deposit in Curry County, Oreg., was first examined by the Bureau of Mines in dune 1945, but it was not until 1952 that the deposit was drilled and sampled. In 1953, a 15-ton sample of Red Flats material was procured and subjected to continuous smelting tests in the Bureau's Northwest Electrodevelopment Laboratory, Albany, Greg.

Jan 1, 1954

By B. E. Blair

Accelerometers of various types, velocity gages, and a displacement meter are shown to give reliable date when measuring seismic pulses generated in rock by the detonation of explosive charges. Displacement and velocity records are differentiated and shown to compare with velocity and acceleration records. Velocity and acceleration records are integrated and shown to compare with displacement and velocity records, respectively. The experimental data are shown to satisfy the scaling laws developed by dimensional analysis. Propagation laws are developed for peak amplitudes of the first pulse of displacement, velocity, and acceleration. These propagation laws are shown to be independent of the gage used to obtain the data. As a result, the usefulness of the various gage types can be extended. For example, accelerometers, because of their high frequency and amplitude limits, can be employed near the shot to measure acceleration and/or velocity (by integration), Velocity gages, because of their higher sensitivity, can be employed at relatively larger distances from the shot to measure velocity and displacement or acceleration (by integration or differentiation).

Jan 1, 1954