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By W. W. Adams

Lower accident rates were the outstanding feature. of the second annual sand and gravel safety competition conducted in 1930 by the United States Bureau of Mines in cooperation with the National Sand and' Gravel Association. Both the frequency and, severity rates for accidents were greatly reduced as compared with those shown by the first year's contest, that for 1929. Three times as many plants were enrolled, and the number of man-hours of work represented was more than doubled. Seventy-six sand-and-gravel plants, situated in 20 States, participated in the Competition, as compared with 26 plants, located in 13 States, in the year before. The number of man-hours of employment, which indicated the amount of exposure to occupational hazards, was 4,915,592, an increase of more than 100 per cent over the previous year's total of 2,259,572 hours. The frequency of accidents declined from 74.4 per million hours for all plants enrolled in the first year's contest to 42.7 per million man-hours for all plants enrolled in 1930. The accident-severity rate was reduced from 9.7 days of disability per thousand man-hours of exposure in 1929 to 5.9 days of disability per thousand man-hours of exposure in 1930. The actual number of accidents reported for 1930 by 76 plants included four deaths and 206 injuries whereas the 26 plants that were enrolled in 1929 reported three fatalities and 165 injuries. Under the rules of the contest all "lost-time" injuries are reported--that is, all injuries that disable an employee for more than the remainder of the day on which the accident occurred. If the employee is physically able to resume his work on the day following the accident, the injury is not classed as a lost-time injury. The contest covered accidents and man-hours worked by all employees at the plant who were employed by the same company, and included work up to the point of delivery of the material directly to consumer or to independent agency of transportation--in other words, to point of relinquishment of control of the material by the producer.

Jan 1, 1931

By W. D. Mcmillan

The Dempsey tract in Washington County, Mo., had a small production of lead-zinc ore from shallow workings. Old dumps from early-day lead mining contain about 25,000 tons of ore averaging about 3 percent combined zinc and lead. Because of the urgent war requirements for lead and zinc, the Dempsey property was examined by Otto Ruhl, formerly an engineer of the Bureau of Mines in August 1942 and selected for further investigation by churn drilling twenty holes totaling 1,309 feet were bored in the fall of 1943. The results of the work are presented in this paper.

Jan 1, 1948

By D. S. Burgess

A commercially available Halon 1301 extinguisher has been evaluated as part of an explosion-suppression system for use in coal mines. Studies were made both of the dispersion pattern of the Halon 1301 at an initial pressure of 280 psig, and of the efficacy of this suppressant against 9.5 percent methane-air flames. These flames were quenched successfully only when the suppressant was applied before the fireball diameter exceeded 18 inches.

Jan 1, 1971

By Griffith. F. E., Glei

"INTRODUCTION For many years protective grounding of electrical equipment has been advocated as a means of safeguarding equipment against damage and of minimizing shock hazards to persons. Several codes are in effect covering in considerable detail the items to be observed in obtaining effective grounding in and about industrial plants. Although the coal-mining industry does not have a comprehensive code of its own covering the grounding of electrical installations, a number of States and individual coal-mining companies have issued codes, standards, or rules that include certain requirements with reference to grounding. As early as 1916, 4/ and again more recently, 5/ the Bureau of Mines recommended grounding, particularly as a means of preventing shock to men working on or around electrical equipment.It is common knowledge among electrical engineers of public utility and mining companies that connecting a wire from the frame of a machine to a rod or pipe driven into the earth does not necessarily assure desired protection of surface equipment. In fact, it has often been found necessary to use several interconnected rods and to treat the surrounding earth with salt or other chemicals before the connection to earth would have sufficiently low resistance to give satisfactory results. Even these expedients have not produced the desired results in some localities. It has also been found that ground connections initially having a low resistance may attain high resistance during some seasons of the year. In spite of such difficulties with surface equipment, it has sometimes been assumed that a mining machine resting on the floor in a coal mine is grounded by virtue of its contact with that floor. It has also been assumed by persons endeavoring to comply with grounding requirements that a peg or rod driven into the mine floor would provide a sufficiently low-resistance contact with the earth to be satisfactory as an electrode for connecting the grounding wire from frames of equipment. That both assumptions may be wholly untrustworthy has been proved by the authors in actual tests with underground machinery."

Dec 1, 1943

By Frank G. Horino

A rock mechanics program (composed of laboratory and field tests) was initiated by the Bureau of Mines in an effort to determine the causes of pillar instability at the Fletcher mine, near Bunker, Mo. Compressive strength, Young's modulus, shear strength, and the angle and coefficient of internal friction were determined on drill cores obtained from 16 different locations in the mine. Results of the laboratory tests showed that highly mineralized zones and brecciated zones in pillars could significantly affect pillar strengths and stability in locations where extraction ratios exceeded the normal design ratio of approximately 78%. High-angle fractures that were present in Some locations also may have contributed to pillar deterioration. In the field tests, in situ stress determinations were made in one pillar to establish the pillar-loading conditions and to evaluate the stability of the pillar. Continued monitoring of stresses in the pillar showed a gradual decrease in compressive stress, indicating that the pillar was probably in the postfailure state. A second stress determination was made in a vertical hole in the underlying igneous rock that was exposed on one section of the mine. Horizontal stresses were compressive and larger than would be expected from gravity loading.

Jan 1, 1978

In March, the Minister of Mines, Mrs. Judy Erola, released a mineral discussion paper at the annual meeting and convention in Toronto of the Prospectors and Developers Association. Among the mineral objectives discussed was the revitalization of the "junior" mining industry. That industry reportedly has seen its share of total exploration expenditures fall from 50% in 1969 to 10% in 1979. Some sources believe the reason to be the rise of exploration costs and more- restrictive legislation The junior mining industry reportedly was responsible for 40% of all mineral discoveries in the 1969-79 period. CZECHOSLOVAKIA Czechoslovakia expects its capacity for the recovery of gallium metal to increase from 1,650 kilograms to nearly 3,000 kilograms per year by the installation of new recovery equipment at the aluminum plant at Ziar Nad Hronom in Central Slovakia. World production data are not reported, but the United States consumed 8,000 kilograms (estimated) in 1981, of which 5,536 kilograms were imported. Gallium is recovered as a byproduct of the Bayer process for the conversion of bauxite to alumina, and from certain zinc processing wastes. It is used for electronic applications such as light-emitting diodes for visual display panels in calculators, clocks, and other instruments.

Jan 1, 1982

By John R. Dudo

The Bureau of Mines Morgantown Petroleum Research Laboratory, with the cooperation of the Penn York Oil Company, cored the Dewdrop, Bradford Third, Lewis Run, and Sartwell sands in the Sartwell oilfield, McKean County, Pa. This report contains a review of the geology and depositional history of the field and an evaluation of the feasibility of secondary recovery of oil from the Bradford Third and Sartwell sands by waterflood or gas drive. Core analysis, geologic data, and electrical and radioactivity logs were used to evaluate the reservoir characteristics. Reservoir geometry, rock properties, fluid characteristics and saturations, and relative permeability-saturation relationships were used to assess the floodability of these two sands. The results of this study indicate that between 53,000 and 61,000 barrels of oil can be recovered by water or gas injection. The success of a waterflood or gas drive will depend on the field injection rates of the reservoirs comprising this oilfield. Following an economic evaluation, additional field work is recommended to further test the floodability of the reservoir.

Jan 1, 1967

By Jerry A. Wichser

A series of linear programmed instruction modules was developed in the general subject areas of Blasting Technology & Explosives Safety & Electrical Training. The linear programs (modules) were developed in the form of tape-slide plus workbook materials, while the branching format evolved from the LTS teaching machine system from MIT, through several other teaching machines and micro-computers, finally settling on Radio Shack TRS-80 microcomputers, Models I & III. Initial validation figures indicate that essentially the same result, are attained from both methods (based on pre and post test scores), with the most noticeable difference being an approximately 25% savings in study time with the branching modules. In December 1980, the development of modules on High-Voltage Training, Trolley Wireman Training, and Compressed Gas Safety was added to the overall tasks of the contract.

Jan 1, 1984

By C. A. Komar

The Bureau of Mines has undertaken an investigation to determine possible applications of acoustic energy at sonic and ultrasonic frequencies to improve ultimate recovery from oil reservoirs. A literature search was conducted to provide background information for initiating laboratory research. The purpose of the literature search was to review the uses that have been made of acoustic energy in the petroleum industry and to select procedures and techniques that could be applied to the solution of petroleum production problems. The characteristics (68)3 of ultrasonic energy make it potentially useful to a variety of industrial and experimental applications. Pulse techniques (99) are common in the testing of materials where inspection is accomplished by propagating an ultrasonic pulse through the material. Viscosity measurements (45) are made by interpreting changes in the absorption of sound as it is propagated through a flowing liquid. Cavitation phenomena (93) produced by high-intensity ultrasound in liquids have been used extensively in industrial cleaning, machining, impact grinding, and aluminum soldering operations.

Jan 1, 1963

By John E. Miller

A high accuracy Burnett apparatus for use at 12,000 psi and 0° to 65° C has been constructed at the Bureau of Mines Helium Research Center. The apparatus is patterned after Burnett's original apparatus, but the working pressure is much higher and elastic distortion can be essentially eliminated. An operating procedure to permit faster experimental measurements is suggested.

Jan 1, 1967

By Robert Howard

With the rapid depletion of the Peerless Coal Co.'s mine in Spring Canyon, it was necessary, if the company was to remain in the coal-producing business, to look to the development of a new property or to acquire a mine already developed. After careful investigation of several operating properties it was decided by the officials of the company to take over the lease on an undeveloped acreage held by a private party in Price Canyon, about 3 miles north of Castle Gate, Utah.

Jan 1, 1930

By Walter D. Holland

This document is one of a series of instruction guides developed to help instructors present health and safety training courses to workers in the metal and nonmetal mining industry. This course is intended to provide above ground metal and nonmetal mining employees with training which will assist them in performing their work safely and healthfully. A document entitled, "Airborne Contaminants in Above Ground Metal and Nonmetal Mining and Processing Work Areas," is used as a manual for the students during the course. The unique features of the teaching guide are thumb rules for recognizing hazardous situations, candidate contamin¬ants for each work area and descriptions of control devices and work procedures.

Jan 1, 1977

By Robert W. Ageton

The Bureau of Mines investigated the in situ vertical component of the rock stress in the rib of the haulage drift on the 6100-level of the Star mine, Burke, Idaho, using the flatjack and borehole deformation methods. The estimate of the vertical component of stress about 2 feet into the rib at a station along the haulage drift on the 6100-level of the Star mine by the flatjack method is approximately 5,875 psi, whereas the borehole deformation procedure at this station yielded a value of 5,500 psi for the same depth into the rib. The test zone is approximately 5,625 feet below the surface.No attempt was made to extrapolate stress estimates beyond the depth of the flatjack installation.

Jan 1, 1967

By R. C. Annear

This report describes open, sublevel, and shrinkage stoping at the Greenwood mine, operated by Inland Steel-Co. The iron ore mine is in Marquette County, Mich., about 6 miles southwest of Ishpeming (fig. 1). The Greenwood is one of three active underground hard-ore mines on the Marquette range, the others being the Cliffs-Shaft and the Champion mines. The operation reflects an achievement in exploiting small, difficult-to-mine hard-ore bodies lying beneath a 200-foot overburden of glacial drift, which is partly water bearing. This report can indicate only briefly the efforts of personnel in overcoming adverse conditions in mining more than 2 million tons of ore, 80 percent of which was in lump form, for open-hearth production of steel. Significant data presented include descriptions of the principal mining methods employed, sublevel and shrinkage stoping; percent aged mining costs for the entire year 1957, covering both direct mining costs and general expenses; and performance records in units of labor, power, and supplies.

Jan 1, 1960

The Aluminum Co. of America raised its 99.5 percent unalloyed aluminum ingot selling price in March by 34 to 514 per pound. Other producers, including Kaiser Aluminum and Chemical Corp. , Anaconda Aluminum Co. , and Reynolds Metals Co., followed Alcoa's lead, raising their quotes to 51$. In late March, domestic merchants quoted ingot at levels ranging between 49.56 and 50.50 per pound. BISMUTH: Several domes tic dealers lowered their bismuth prices in recent weeks by 50t-606 to within a range of $5.60-$5.75 per pound; producers continue to hold published prices at $7.50.

Jan 1, 1977

By Nicholas Kyriazi

The Bureau of Mines subjected three commercial compressed-oxygen self-contained self-rescuers to a series of laboratory treatments designed to simulate various environmental conditions in underground coal mines. The environmental treatments consisted of extremes of temperature and of shock and vibration. The tests were designed to predict the ability of the self-rescuers to withstand those environmental stresses without causing a decrease in wearer protection. A critical concern was internal damage to an apparatus that would cause it to malfunction or seriously degrade its performance without any obvious external signs. The Bureau has previously tested chemical oxygen self-contained self-rescuers in a similar research program. Although the three compressed-oxygen units are not as sturdy as the chemical oxygen self-rescuers tested previously, they performed reliably after treatments on treadmill tests with human subjects and on machine tests using a breathing and metabolic simulator. Serious damage was caused by both the heat treat-ment of 71° C (venting of the 02 bottle in most cases), and in the shock treatment (breaking open of the case and dislodging of the components). When physical damage is obvious, a complete refurbishing of the damaged self-rescuer is recommended.

Jan 1, 1983

By T. E. Gray

This report describes the preparation characteristics of the signifi¬cant coalbeds in Preston County, W. Va. It is one in a series of reports planned to determine coals suitable for the production of metallurgical coke, either as mined or after beneficiation. Over 2 million tons of coal was produced in Preston County, W. Va. in 190, none of which was cleaned mechanically. Estimates as of January 1, 1959, indicate that more than 3 billion tons of coal remained in the county in beds 12 inches or more thick. The Bakerstown, Mahoning, Upper Freeport, and Upper Kittanning beds were selected by the Bureau of Mines for study based on current production and estimated minable reserves. Sample locations were selected after study of the literature, conferences with mining engineers and mining company offi¬cials in the field, and examination of available sites. Four samples were collected from the Bakerstown and Upper Freeport beds and one each from the Mahoning and Upper Kittanning beds.

Jan 1, 1961

From 1886, the first year shipments were recorded, until 1939, the Leadville district produced over 3,500,000 long tons of manganiferous ore. Of this total, metallurgical-type ores comprised 27 percent and manganiferous iron ores suitable for fluxing in lead smelters made up 73 percent. In 1939, the Bureau of Mines, as part of the strategic minerals investigative program being conducted at the time, requested the Mineral Industries Survey Section of the Mining Division to make a comprehensive study of the manganese resources of the Leadville area. This investigation, owing to the caved and flooded condition of the underground mine workings, was necessarily confined to a study of old maps, production records, and geological reports, and the results were published as an Information Circular in July 1940.

Jan 1, 1949

By R. Hogg, T. F. Dumm

"A procedure for evaluating the size/specific gravity distribution of ultrafine coal and the distributions of sulfur and ash with respect to particle size and specific gravity is described. The procedure is essentially an extension of the conventional coal washability technique in which special precautions are taken to ensure particle dispersion in the heavy organic liquids, centrifuges are used to obtain adequate separation rates, and micromesh sieves are used for size separation at fine sizes. An example of the application of this technique to the evaluation of the extent of liberation of sulfur and ash in a coal sample ground to 90Z passing 200 mesh (74 um) is described.INTRODUCTIONIn order to determine the potential for deep cleaning of coal by fine grinding to liberate sulfur and ash-forming minerals, it is necessary to obtain data on the distributions of these species by size and specific gravity. In conventional coal processing operations, this information is obtained by means of a standard ""washability"" analysis. Attempts to extend this procedure to ultrafine coal, however, have generally been unsatisfactory and have often led to unreliable and inconsistent results [11. The present authors have described a modified washability procedure in which cumulative specific gravity fractionation is combined with sub-sieve size analysis (by laser diffraction/light scattering) to determine the particle size/specific gravity distribution of ultrafine coal [2]. Unfortunately, because this technique does not involve separation of the individual fractions, only limited information can be obtained on the specific distributions of sulfur and ash.The objective of the work described in this paper was to develop and evaluate a procedure for size and specific gravity fractionation of ultrafine coal and to use conventional analyses for sulfur and ash to determine their relative distribution in the coal. The procedure is essentially a simple extension of the standard washability analysis [3] but incorporating special precautions for treating ultrafine particles.EXPERIMENTAL Material The material used in the development and evaluation of the ultrafine coal fractionation procedure was a medium volatile bituminous coal from the Lower Kittanning seam. A sample of the coal (nominally - 1/4 inch), obtained from the Penn State Coal Data Base, was ground to 90% passing 200 mesh by the following two-stage grinding procedure: About 2 kg of the as-received coal were ground to about 30Z passing 200 mesh in a Model 4-E Quakertown mill (""coffee grinder""). About 1 kg of this product was then ground to about 90Z passing 200 mesh in a Holmes Model 300 Pulverizer."

Jan 1, 1989

By Charles W. Huggins

Knoop hardness indentations were studied and measured with the electron microscope on TiB2, HfC, and A1B12 crystals. A detailed description of replicating the indentations using collodion and Faxfilm is made. A John Hopkins grating having 28,800 lines per inch was used to accurately determine the magnification used on the electron microscope. The primary objectives were to prepare carbon replicas of hardness indentations, to measure the indenations accurately, and to compare the results with those obtained with the light microscope. The resulting data showed excellent agreement between the measurements made on the replicas with the electron microscope and those made with the optical microscope. The replicas made from collodion showed slightly better agreement with the light optical values than did the replicas made from Faxfilm.

Jan 1, 1963