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By V. R. Spironello

The Bureau of Mines is involved in research directed toward the conserva¬tion of important raw materials and the utilization of solid waste. Two of the objectives are to conserve high-quality coking coals used for foundry coke and to utilize waste materials of marginal quality but of high calorific value. These objectives are consistent with Bureau goals. Pilot plant cupola trials were made to evaluate the adequacy of various alternative fuels, and to determine to what extent they could replace the foundry coke in cupola charges. Information was obtained on furnace performance, metal and slag chemistry, environmental questions, and the properties of castings. It was shown that anthracite or bituminous coals can partially replace charge coke up to the 40 pet level. Briquetted materials prepared from fuel fines, and waste prod¬ucts or byproducts of high calorific value, all tend to break down on heating in a cupola so that their use must be restricted to below 20 pet replacement. In cases where pitch-bonded coal fines or petroleum coke were used, carbon pickup by the iron was inadequate for gray iron specifications. Although emphasis during this work was placed on basic slag practice, some acid practice results are included.

Jan 1, 1980

By Frederick H. Raab

An electromagnetic (EM) system for the location of trapped mine workers at coal-mine (300 m) depths has been developed. The use of such a system in deep mines (1-km depth) requires transmission at extremely low frequencies (ELF) and a reduction in the effective noise level beyond that which can be obtained by acceptable Integration times. Automatic-noise-cancellation (ANC) techniques reduce the effective noise level by combining several received signals that contain correlated noise. Such signals can be obtained either from a remote magnetic antenna or a local electric antenna. During Phase III of this program, real ELF noise data were acquired and used to test the ANC algorithms developed during Phase II. The ELF noise data were obtained from analog recordings made by Develco under another Bureau-of-Mines contract. Digitization was accomplished by an ND converter that was added to a GMRR computer. Phase III tasks Included preparation of software for digitization, computer-computer communication, data processing, and statistical analysis. Useable data were obtained from eleven half-hour tapes containing noise from one axis of the primary antenna and three axes of the remote antenna. The overall average Improvement in SNR was 4.1 dB. However, the average Improvements for the Individual X, Y, and Z axes were 4.2, 11.9, and -1.9 dB, which roughly follow the observed noise power. Nonlinear processing was not effective with this noise.

Jan 2, 1984

By Robert F. Randolph

Introduction This paper is a descriptive analysis of injuries and fatalities at small surface bituminous coalmining companies in Pennsylvania. The purpose of analyzing a specific industry sector and location is to identify issues that might be missed in a wider analysis. Other studies of small mine safety (e.g., Peters and Fotta, 1994, Randolph and Boldt, 1997) have shown that the relationship between safety and mine size is not a simple one. Some injury types occur at higher rates at small mines, while others occur at lower rates. Consequently, an analysis limited to a specific type of mining can help identify hazards and issues specific to that sector. The results of this analysis will be useful for directing training, intervention, and research efforts towards the most prevalent causal factors and incident types. Procedures and Definitions Data sources The primary sources of data for this analysis were files provided by MSHA containing information collected under Title 30 Code of Federal Regulations, Part 50. These files, commonly referred to as “Part 50 data”, are provided though MSHA’s Program Evaluation and Information Resources directorate. Two primary types of injuries were selected from the Part 50data: Fatalities (MSHA “degree of injury” code 1) and lost-time injuries, otherwise known as nonfatal with days lost (MSHA “degree of injury” codes 2 through 5). Lost-time injuries involve either actual days away from work or days of restricted activity or both. Fatality and lost-time injury incidence rates were calculated using the standard MSHA formula: Number of injuries per 200,000 employee-hours. Additional information on company sizes and mine ownership was provided by the Pennsylvania State University College of Earth and Mineral Sciences. Time span A five-year time span was selected for this study. More than a single year of safety experience is usually needed to capture a broad range of incident types. Many types of injuries, especially fatal injuries, can be extremely rare, and may be missed if too short a time span is selected. However, a time span that extends too far back may begin to suffer historical threats to validity. That is, incidents that occurred several years ago may be caused by hazards that have since been remedied or may be related to mining practices and conditions that no longer exist. A five-year span offers a practical compromise between these two concerns. Consequently, the MSHA Part 50 data files from 1993 through 1997 were used. The 1997 file was in “preliminary” form at the time of the study, so small variations from the final 1997 “close out” file can be expected. Based on past experience, we do not expect the close-out variations to have a significant impact on the findings.

By John J. Sammarco

The mining industry has the highest average annual fatality rate among major U.S. industries. To address this, the National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory (PRL), is conducting major research programs to reduce the hazard exposure of miners. One of the recently concluded programs at PRL developed the enabling technology for remote-controlled mining. An application involves the manual process of extracting and hauling coal where operators, in the tight confines of a mine, can be struck or caught by mobile machinery. The approach to remedy this problem uses a guidance system on the continuous haulage equipment so that it follows the continuous mining machine that extracts coal. This, in essence, involves sensor-based docking of the machines. Sensors functioning in the hostile mine environment of dust, methane gas, and water play the key role. Computer analysis of the mining machine's movements and empirical machine characterizations established operating requirements and spatial limitations to ensure proper loading of coal into the haulage equipment. These data served in the selection of a guidance sensor. Technologies such as scanning laser systems and ultrasonic sensors have frequently been used in other applications, but were found unacceptable. However, a near-infrared sensor employing active targets met the requirements. The sensor has a nominal 75b conical field of view and a range from 0.1 to 18.0 m. For the single-target mode, nominal range accuracy was 4.3% at a distance of 3.65 m. Correction algorithms were generated, which reduced the error to 0.6%. Airborne dust testing showed less than an additional0.8% accuracy (worst case) degradation at dust levels up to 15 mg/m3. Using four targets, the nominal range accuracy was 0.4% without correction algorithms. Analysis of dynamic testing of a continuous miner and haulage showed that accuracy was maintained and total target loss did not occur. A guidance system for the haulage system to follow the mining machine does not exist commercially. Such a system can reduce fatalities, injuries, and exposure to dust and noise.

Jan 11, 1998

By W. W. Staley

This paper discusses the design of small head frames that will fill the needs of prospectors and small operators whose operations are conducted through shafts. The head frames considered were designed to handle relatively small tonnages. It was assumed that the shafts in which buckets are used would not exceed 300 feet in depth and that not over 60 tons of rock would be hoisted, in, 14 hours. In the design of the larger head frames, a hoisting capacity of about 250 tons per 6 hours from a depth of 300 to 500 feet was assumed. Under these conditions, hoisting speed, rate of acceleration, and weight of rope have a negligible effect on the head frame design and, therefore, have been ignored in the following, discussion. Because timber is relatively cheap and easily obtained in most mining areas, the discussion has been confined to timber construction.

Jan 1, 1937

By B. W. Gandrud

The upper part of the Alabama deposits of crystalline graphite consists of an oxidized ore derived from, the underlying unoxidized ore through prolonged weathering. The degree of oxidation in different sections and at different depths within the bed is nut. uniform. The original ore is hard and blue-gray; the weathered product is soft and brown and is the only part that has been mined to any extent. Samples of both oxidized and unoxidized ores were obtained from two of the large graphite deposits of Clay County. Three additional samples of oxidized ore were obtained from different portions of a third property in the same region. In this report, ores 1 to 5 are of oxidized material and ores 6 and 7 of unoxidized.

Jan 1, 1934

By Mark Sheppard

The technical literature on the general subject of crushing contains many references to the work of investigators on the laws governing, and the factors entering into, the economical production of fine materials. In fine grinding, whether for the purpose of producing fine material, or for the unlocking of minerals in an ore, close control of the screen sizes of primary-crusher products is of secondary consideration and accordingly has received very little attention. The growth and development of the nonmetallic industries, however, have drawn more attention to primary crushing. Many of these industries are interested in the production of relatively coarse products that meet certain definite size specifications, a condition entirely different from that existing in the field of ore dressing. Under such conditions, a knowledge of the factors governing the selection and operation of primary-crushing equipment is essential to the economical production of a satisfactory material.

Jan 1, 1939

By Mackenzie Burnett

Quick-Fix Blowout Stoppings were evaluated in several underground mines as an alternative to conventional ventilation control bulkheads. Blowout stoppings offer considerable savings in bulkhead construction and repair costs if the 0.1 inch H20 of differential pressure required to inflate them is available. The Quick-Fix Blowout Stoppings were utilized successfully in uranium mines in the Southwestern United States where savings in bulkhead construction and repairs to blast damaged bulkheads are estimated to equal $9,500 over the projected 2 year average life of a blowout stopping. Two types of material were evaluated. Five methods of anchoring the stoppings to drift walls were evaluated. Three methods of anchor attachment to the stopping material were evaluated. Blast pressure measurements were made in conjunction with the evaluation of the blowout stoppings.

Jan 1, 1978

By Walter D. Holland

This study was undertaken to determine miners' breathing zone concentrations of diesel exhaust components, to investigate any relationships between these concentrations and vehicle type, the presence of emission controls, vehicle usage, and ventilation conditions, and to make recommendations for monitoring and ventilation requirements. Twenty-four mines including two con l mines were surveyed. Sampling was done for CON, NON, SOx, PNA, aldehydes, and particulates. hi most mines, concentrations of at least one contaminant exceeded one half the standard or TLV. The concentrations of gases arc probably sufficiently reduced by a minimum air velocity of 50 fpm. A sufficient reduction of particulate concentrations may require as high as 400 fpm air velocity. Vehicle age, type, or usage appear to have little or no effect on contaminant concentrations. PNA levels were below detection limits in all but a very few samples. Minimum requirements for routine monitoring should include formaldehyde, COx, NO2. It is further recommended that better definition of the minimum ventilation requirement be obtained.

Jan 1, 1978

By Mark Sheppard

The technical literature on the general subject of crushing contains many references to the work of investigators on the laws governing, and the factors entering into, the economical production of fine materials. In fine grinding, whether for the purpose of producing fine material, or for the unlocking of minerals in an ore, close control of the screen sizes of primary-crusher products is of secondary consideration and accordingly has received very little attention. The growth and development of the nonmetallic industries, however, have drawn more attention to primary crushing. Many of these industries are interested in the production of relatively coarse products that meet certain definite size specifications, a condition entirely different from that existing in the field of ore dressing. Under such conditions, a knowledge of the factors governing the selection Paid operation of primary-crushing equipment is essential to the economical production of a satisfactory material.

Jan 1, 1939

By Robert W. Geehan

The Bureau of Mines has been developing deposits of critical and essential minerals in the United States since 1939. A preliminary examination of the Union lead mine was made in November 1944 and January 1945 by W. T. Benson, a Bureau of Mines engineer, who recommended development by diamond drilling. The Bureau conducted a drilling project at the mine from February 12 to May 16, 1947. The property is in sec.12, T. 17'N., R. 19 E., Mount Diablo Base and Meridian, in. southern Washoe County, Nev., about 15 miles south of Reno. The Union lead mane, also known 4s the Commonwealth mine, has been an intermittent producer of zinc-lead-silver ore since 1860. During World War II, ore was shipped to smelter& near: salt Lake City, Utah. The Bureau drilled 21 diamond-drill holes having a total length of 1,549 feet and 20 long percussion-drill holes with a total length of 359 feet. The program was designed to test for horizontal and vertical extensions of the ore body and to prospect for parallel ore bodies. As a result of this program, extensions of the ore zone were established, but no parallel ore-bearing structures were found. The areas drilled were limited by drill sites available.

Jan 1, 1950

By Spangler Ricker, F. T. Johnson

"SUMMARYThe Ione-Carbondale clays area is 2 miles northwesterly of Ione, Amador County, Calif. It was explored during the war by the Bureau of Mines to obtain data on the alumina content and to recover representative samples for beneficiation tests for alumina recovery.Seventy holes, aggregating 8,837 feet, were drilled, and about 10.3 acres of land was cleared of underbrush. Maps and cross sections were compiled showing location of holes, analyses, and other pertinent data.The clay beds vary in thickness from 13 to 196 feet, and are covered by a loose overburden, averaging about 11.9 feet in thickness. The ratio of overburden to clay is 1 : 8.2. Analysis of a composite sample showed the recoverable alumina (A12O3) and Fe2O3 content to be in the order of 23.6 percent and 2.8 percent, respectively.Topography of the clay area is ideal for open-pit mining methods and plant site.INTRODUCTIONInvestigation of alumina-rich clays for the possible production of aluminum was made during the recent war period, when the shortage of bauxite was becoming critical.Results of field examinations by the Bureau of Mines and the Federal Geological Survey indicated that one of the most promising areas for the development of alumina-rich clays is in the Ione-Carbondale district."

Mar 1, 1948

By J. Girard-Dwyer, T. Camm

Direct costs such as medical, legal, administrative, and worker’s compensation costs, property damage, lost earnings, and lost benefits are typically used to compute the economic impacts of occupational injuries. However, there are also a number of less obvious, indirect costs that substantially contribute to the overall loss costs. In fact, for every $1 of direct costs an estimated $3 to $5 of indirect costs are also incurred. This paper presents a systems approach that incorporates engineering, economics, psychology, and sociology in order to evaluate the total value of investments in safety. By studying the interrelated system comprised of the injured worker, their family and coworkers, as well as the organizational structure that was the setting for the incident, a methodology can be developed that will more accurately capture the true costs of mine injuries.

By Ronald T. Mayerle

The Condrey Mountain RARE II area lies mostly within the Elliot Creek mining district, a significant producer of gold from placers, and gold, Silver, copper, and minor soapstone from lode deposits. No mineral production has occurred within the study area; no resources are known in the area. However, significant resources in lode and placer deposits are just outside the west and northwest boundary of the area. The Blue Ledge Mine (fig. 1, no. 15) adjacent to the western boundary, is reported to contain 226,000 ton; (205,000 t) of identified resources averaging 0.05 oz gold per ton (1.7 g/t), 2.16 oz silver per ton (/4.0 g/t), 3.5 percent copper, and 3.95 percent zinc. The mine has produced 11,131 tons (10,114 t) of ore that yielded 1,026 oz (31,908 g) of gold, 58,431 oz (1.8 million g) of silver, and 2.7 million lb (1.2 million kg) of copper. Exploration is currently underway at `he mine and vicinity, including part of the study area.

Jan 1, 1983

By Edward L. McHugh

The study area, which comprises 11,500 acres, includes the 9,610-acre Whitewater Wilderness Study Area, in the California Desert Conservation Area, 15 miles northwest of Palm Springs, CA. The U.S. Bureau of Mines evaluation of mineral resources is based on examination of prospects and mineralized areas during the spring of 1981. The Whitewater study area is mainly underlain by granodiorite to quartz diorite and their gneissic equivalents in an igneous-metamorphic complex. Late Tertiary sedimentary and volcanic rocks locally overlie the crystalline complex in the eastern part of the study area. The study area lies between branches of the San Andreas fault system.

Jan 1, 1986

By G. W. Jones

The results presented in this report deal with the elimination of explosion hazards of ether-oxygen mixtures by the addition of helium. The method is based upon the fact that every combustible gas, vapor, or dust will not burn or explode when the oxygen content of the mixture is reduced below certain definite values. These critical oxygen values are usually different for each combustible, varying with the percentage of the combustible present in the mixture and also with the inert gaseous material used to reduce the oxygen content of the mixture.

Jan 1, 1941

By Douglas F. Scott

Researchers from the U.S. Bureau of Mines conducted geologic investigations in an area of the Lucky Friday Mine, Mullan, ID, that included the 5300-107 demonstration stope using underhand longwall cut-and-fill mining. Structural analysis of the area suggested that argillite beds form planes of weakness between blocks of brittle quartzite, and energy may be released along these planes and at the junctures of fractures. Mapping argillite beds and fractures in the stope wall rock showed that the planes of these features diverged and that their attitudes corresponded from one wall to the other. Seismic analysis showed that the number and location of events varied as each cut was mined, with about 39 pct of the total number of events occurring above the cut being mined, about 54 pct below, and 7 pct at the same elevation.

Jan 1, 2010

By H. W. Wainwright

.1. The purification pilot plant and the equipment, solution, and gas cycle used for removing hydrogen sulfide and carbon dioxide are described. 2. As sulfur recovery is necessary in any large Fischer-Tropsch plant, pilot-plant runs were made at 300 p.s.i.g. to study the efficiency of tri-ethanolamine solutions in removing selectively hydrogen sulfide from gases containing varying amounts of carbon dioxide. 3. Aqueous solutions of TEA of 20, 30; 35, and 50 percent were investi¬gated. Data indicate that 30 to 35 percent is the optimum concentration if both selectivity and economy are considered. Slightly better selectivity is obtained with the.20 percent solution, but steam consumption is greater owing to the higher solution rates. Results from our pilot plant runs indicate that a 50 percent solution not only produces an acid gas of lower hydrogen sulfide content but also requires high solution rates to effect hydrogen sulfide purification. 4. Data from 37 runs using TEA are presented in tabular form. In addition, the data are correlated and presented in three sets of curves. By using these curves, it is possible to calculate the compositions of the purified and acid gases for various raw gas mixtures. 5. In cooperation with the Southern Natural Gas Co., investigations were carried out at 300 p.s.i.g. on the simultaneous removal of hydrogen sulfide and carbon dioxide, from gases using various concentrations of diethanolamine. 6. Data from 17 runs employing 20, 30, and 40 percent DEA are reported in both tabular and graphic form. 7. A comparison of the data from one DEA run made at 200 p.s.i.g. with those from the runs operating at 30O p.s.i.g. shows float the absorption capacity of the solution, and, hence, the steam requirements per gallon are about the sage for both pressures. .The only real advantage of the higher pressure is the additional volume of gas that can be treated. 8. The quantity of steam needed to reactivate fouled TEA and DEA solutions increased as the reactivator pressure was increased about 1,0 to 1.1 pounds of steam was required for each gallon of circulating solution when the reactivator was operated at 5 p.s.i.g. 9. A curve is included that shows the effect of the hydrogen sulfide con-centration in a lean 35 percent TEA solution on the hydrogen sulfide content of the purified gas and on steam consumption for reactivation. 10. Both TEA and DEA reduced the organic sulfur content of the raw synthesis gas considerably. Analyses of the lean amine solutions showed a gradual build up of sulfur compounds, indicating that the compounds formed by the amines and organic sulfur do not break down under the ordinary operating conditions of the reactivator. 11. Considerable operating difficulty was encountered in the pilot plant owing to foaming of the amine solutions. Laboratory experiments in which the effectiveness of certain antifoam agents was studied showed Alkaterge C to be most promising for the particular conditions studied.

Jan 1, 1952

By G. W. Jones

The results presented in this report deal with the elimination of explosion hazards of ether-oxygen mixtures by the addition of helium. The method is based upon the fact that every combustible gas, vapor, or dust will not burn or explode when the oxygen content of the mixture is reduced below certain definite values. These critical oxygen values are usually different for each combustible, varying with the percentage of the combustible present in the mixture and also with the inert gaseous material used to reduce the oxygen content of the mixture.

Jan 1, 1941

By Kenneth Maas

The Bureau of Mines devoted portions of the 1987-1988 field seasons to investigate the mineral aggregate industry in Juneau, Skagway, Haines, and Gustavus, Alaska, as part of the Juneau Mining District study. Statistics compiled for current suppliers include location, activity, reserve estimates, expected mine life, and types of commodities available. Each population center, except for Gustavus, is well endowed with suitable mineral aggregate to last at least 20 years. The Bureau of Mines quantified the mineral aggregate resource in many large potential sites within each area. Sampling, engineering and soil-index testing, site descriptions, deposit dimensions, and gold recovery information is described. Refraction seismic studies performed at three localities revealed gravel thicknesses in excess of 40 to 80 feet. In the Juneau area the Herbert/Eagle Rivers outwash area, East Fork Lace River. Antler/Gilkey Rivers, and Grizzly Bar (Taku Inlet) individually contain in excess of 60 million yd3 of excellent-quality aggregate with minor accessory gold credits. Haines is also well endowed with aggregate resources; large, quality deposits occur along and at the confluences of the Chilkat, Katzehin, Klehini, Tsirku, and Kicking Horse Rivers. Large deposits of granitic aggregate exist in the Skagway River and East Fork Skagway River.

Jan 1, 2012