Search Documents

By J. R. Koehler

The U.S. Bureau of Mines (USBM) ground control research program includes several projects focused on developing design criteria for yielding-pillar-based longwall gate road systems. As part of this program, mining practices at the Sunnyside Mines, Sunnyside Reclamation and Salvage Co., Sunnyside, UT, are being documented to preserve the long history of yield pillar system evolution on the property. Published information describing the specific in-mine performance of the numerous gate road configurations utilized at the Sunnyside Mines is very limited. To overcome this deficit, USBM personnel interviewed 30 longtime mine employees representing nearly 700 years of mining experience at the Sunnyside operations. Mining conditions in 12 specific areas in the Nos. 1, 2, and 3 Mines were discussed in the interviews. Also, broad topics such as general mining practices, safety, and geology were often addressed during the discussions. Comprising the body of this report is an extensive record of the events and conditions experienced while mining the identified areas. In addition, eight significant conclusions were developed that accurately summarize the general opinions of the interviewed personnel regarding mining conditions and practices at Sunnyside.

Jan 1, 1994

By B. W. Gandrud

[This report presents the data of one of a series of investigations of the washability of Alabama coals as indicated by float-and-sink tests mode by the Bureau of Fines at the Southern Experiment Station in cooperation with the University of Alabama and Alabama coal producers. The Klandyke mine, operated by the Blocton Mining Co., is about 1 mile eat of Vest Blocton, Bibb County, Ala., floor the southwestern, extremity of the Cahaba coal field. The Bureau of Mines already has published three reports that deal with the, washability of Cahaba coals - one a washability study of the Clark bed at Marvel4/ one on the tabling of fine coal from the Thompson and Woodstock beds5/, and the third a washability study of the Henry Ellen bed at Acmar6/.]

Jan 1, 1939

By A. D. McMahon

Changes in world mine and smelter supply sources of zinc have led to changes in zinc supply patterns in the United States during the past 3 years, 1970-72. The result has been a growing reliance on foreign sources of zinc metal to furnish an ever-increasing portion of expending domestic requirements. This review of fundamentals and historical developments is intended to provide background in order to place the future of the U.S. zinc industry fn perspective. The properties and uses of zinc are described. A new study on U.S. reserves is presented with description by geographical region and comparisons with older reserve data. The technology of the zinc industry from prospecting through refining is described with emphasis on the metallurgy involved in the various methods of smelting. Production, consumption, and imports are discussed and illustrated with graphs and tables to review the past and present patterns. Government actions affecting the industry are shown.

Jan 1, 1974

By William A. Stickney

The zirconium-hafnium separation plant at Albany, Oreg., was the result of a chain of events that started with studies by A. R. Kaufmann at the Massachusetts Institute of Technology. Variations in the listed neutron-absorption cross-section of zirconium caused him to suspect a misprint. As a result of these discrepancies and following his suggestions, Oak Ridge scientists made studies establishing a value of 0.4 barn or lower. This meant that the potential of zirconium for reactor application was greatly enhanced. Since hafnium is invariably associated with zirconium and has a high neutron cross-section, it was necessary that an efficient hafnium-separation method be developed before the superiority of zirconium as a structural material in nuclear reactors could be realized. The Albany plant was built and operated for the Atomic Energy Commission (AEC) under Letter Agreement AT-(11-1) -140, patterned after a plant operated by the Carbide and Carbon Chemicals Corp. at Oak Ridge, Tenn. Construction was begun in April 1951. Hafnium was to be extracted preferentially as hafnium thiocyanate from an aqueous mixture of zirconyl and hafnyl chlorides in hexone (methyl isobutyl ketone) by a liquid-liquid countercurrent system.

Jan 1, 1959

By W. L. Brien, O&apos

Molybdenum alloys with good strength properties at elevated temperatures were produced by the powder metallurgical internal oxidation method previously applied to tungsten and known as oxyreaction strengthening. Commercial molybdenum powders were blended with 0 to 10 pet of a reactive powder, ZrMo2. The effects of composition, blending procedure, and sintering conditions on strength properties at elevated temperatures were studied. Strengthening was attributed to zirconium in solid solution with molybdenum and to the presence of submicrometer particles of Zr02. Several alloys had tensile strength and stress-rupture properties com-parable with those of the best commercial alloys. The maximum tensile strengths obtained were 92 kpsi at 1,200° C and 53 kpsi at 1,316° C. The maximum stress-rupture life at 30 kpsi and 1,200° C was 145 hours.

Jan 1, 1974

By R. N. Hambright

Gaseous and particulate exhaust emissions are characterized for a 1200 Bhp two-stroke cycle diesel, a 1000 Bhp four-stroke cycle pre-combustion chamber diesel, and a 900 Blip four-stroke cycle, direct injection diesel using steady-state modal testing and a versatile exhaust dilution-collection system. In addition, a 1.50 Bhp four-stroke cycle, pre-combustion chamber, turbocharged diesel was characterized for use in experimental water injection evaluations. Water injection downstream of the turbocharger compressor and upstream of the turbocharger exhaust turbine are evaluated for their particulate removal effectiveness on the small turbocharged diesel engine. The water droplets are inertially separated using cyclone separators designed for minimum pressure drop and outsize, lip to 50 percent of the total particulate mass generated was removed using a combination of both inlet and exhaust water injection techniques.

Jan 1, 1981

By Kenneth M. Smith

The kaolin deposits of Aiken County, South Carolina (fig. 1), have been worked continuously since 1852. It has been long known that the deposits contain a high percentage of' alumina and that large reserves exist. These facts led to the early selection of' this area for examination in the search by the Bureau of Mines for high-alumina clays. An exploratory program was started by the Bureau, and drilling was carried on from. June 27, 1942, to October 31, 1942. The kaolin-bearing district occupies an area approximately 25 miles long and 11 miles wide, running northeast, with its center at Aiken, S. C. (fig. 1). Within this district, a triangular area bounded by Horse Creek, Silver Bluff Road, and Hamburg Road was roughly prospected by boring 43 machine and 12 hand holes. As a result of the data obtained, a final smaller area was chosen for more systematic prospecting. This area is bounded by Pine Log, Tewkesbury, Silver Bluff, and Craig Sawmill Roads and covers about 4,000 acres. Mineral exploration agreements covering 11,272 acres were signed by 35 property owners, and 11,956 feet was drilled in 200 holes on these properties.

Jan 1, 1949

By Robert J. Timko

This U.S. Bureau of Mines study examined spontaneous heating episodes in coal mine pillars in an active underground coal mine. The information obtained from these incidents was then analyzed to learn which sampling methods provided the earliest indication of pillar heating. The objective of this study was to discover if the location of future events of pillar spontaneous heating could be inferred from the available information. The spontaneous heating-prone area in this evaluation involved pillars located just inby the mine portals. Several detection methods were used to determine gas levels outside as well as inside the affected pillars. It was hoped that, by incorporating external and internal sampling methods into an organized pro-gram, locations undergoing spontaneous heating could be determined more readily. This study found that by drilling small-diameter boreholes into the pillars, then obtaining gas samples from the affected pillars, the ability to locate early spontaneous heating episodes was improved. However, the ability to accurately predict future spontaneous heating events remains in question.

Jan 1, 2010

By William D. Monaghan, Michael A. Trevits

Over the period 2000 to 2003, roof falls have accounted for 4 to 14% of the fatalities in underground mining operations. The National Institute for Occupational Safety and Health (NIOSH) is conducting research to reduce the frequency, exposure, and risk of these events through an ongoing program of field and laboratory studies. One area of research involves the evaluation of polyurethane grouting technology that is commonly used to stabilize fractured mine roof strata. Concurrently, NIOSH is conducting work to evaluate the application of ground penetrating radar for advanced delineation of problematic mining areas. In this study, NIOSH partnered with Sub-Technical, Inc. who injected a polyurethane grout (also known as glue) into a roof area of NIOSH’s Safety Research Coal Mine. The mine roof area was scanned using ground penetrating radar technology before and after grout injection in an attempt to determine the extent of grout infiltration. A comparison of the pre-and post-grouting radar records showed a significant change at a mine roof depth of about four to five feet. The interpreted radar records were then compared with drill core information, borescope evaluation of roof-bolt holes in the study area, and underground observations. At this site, the interpretations of the radar records correlated with data obtained from the core holes, borescope evaluations and underground observations. This study showed that ground penetrating radar technology can be a useful tool for detecting changes in mine roof due to the injection of the grout.

By E. R. Palowitch

Two samples of the Lower Hartshorne (Spadra) bed were collected: A sample of the raw coal with the machine cuttings excluded, and a sample of the machine cuttings exclusively. Analysis of the 5-inch by 200-mesh size fraction of the raw coal, excluding machine cuttings, showed that a product meeting minimum quality specifications could be produced by washing at 1.60 specific gravity, yielding a theoretical 93.7 percent of clean coal. A negligible amount of near-gravity material at the separation gravity indicated an easy washing problem. The sample of machine cuttings had a maximum size of 2 inches and contained about 50 percent ash. Washability tests of the 2-inch by 200-mesh size fraction indicated that a theoretical yield of 30.0 percent of specification-grade coal could be achieved by washing at 1.49 specific gravity. As the machine cuttings represent an estimated 10 percent of the total coal mined, their inclusion in the mine output would increase the theoretical net yield of salable coal by only 3.7 percent. Because the machine cuttings contained a high percentage of sink 1.80 specific-gravity material, they had neither an effect on the separating gravity required to clean the raw coal nor on the difficulty of separation. Gabbing underground versus transporting the cut-tings to the surface for disposal or washing either separately or combined with the raw coal involves a number of practical, economic; and intangible factors; hence, no specific recommendations could be made. A discussion of some of the factors involved in dealing with a similar problem is given by Gandrud and Riley.4

Jan 1, 1962

By Richard Rittenhouse

This program was to develop a new base line system for automated continuous room and pillar type mining. The primary requirement estab¬lished for this machine is that the machine be capable of mining and bolting simultaneously. Additionally, this machine was to provide temporary and permanent roof control, have a productive - full - face semi-automatic mining system, leave a clean entry outby the machine, provide maximum operator protection, provide effective dust suppression and provide air scrubbing to restrict respirable dust to permissible levels. The machine has effectively demonstrated the ability to mine and bolt simultaneously. Additional above ground operation, testing, and time studies are recommended to further verify the machines abilities. Design improvements are recommended for future generation AES machines. These relate to marginal design areas such as side loading on vent duct lift cylinders, etc., that will not impair additional testing of the existing machine.

Jan 1, 1983

By Rudolf E. Greuer

This study concerns itself with two topics of the mine ventilation - mine fire interface which, when the work for this study began, did not seem to receive sufficient attention. Section 1: Comments on Spontaneous Combustion of Coal in Mines It is attempted to describe heat generation, heat and oxygen transport, in such a way that existing experimental data for U.S. coals can be used to assess conditions inducive to spontaneous heatings quantitatively. Investigated are, in particular, critical air velocities, minimum sizes of coal accumulations, moisture contents and the influence of mining factors. An extensive, practice oriented literature survey is included. Section 2: The Early Detection of Mine Fires by Assessment. of Mine Gases The suitability of the major constituents of combustion products for an early detection of fires is discussed. The same is done for gas concentration ratios. Since it was felt (at least at the time when this report section was written) that the value of the carbon monoxide/oxygen deficiency ratio was overestimated, the usefulness of monitoring this ratio as compared to monitoring CO concentrations was critically investigated. The state of art concerning instrumentation and organization of fire detection systems is reviewed also.

Jan 1, 2011

By John C. Machisak

THIS INFORMATION CIRCULAR covers the calendar year 1055 and contains statistical data on employment and injuries pertinent to metal and nonmetal mining and to their mills and processing plants that are voluntarily reported annually to the Federal Bureau of Mmes. This report, unlike previous publications, lists not only production and development workers but also office employees associated with mining and milling or processing. The last publication m the series, Information Circular 7798, Injury Experience in the Metal and Nonmetal Industries, 1954, also contains unpublished injury and employment statistics for 1943 through 1953. The Bureau is authorized to request data on injuries and employment from operators in the metal- and nonmetal-mining industries. The information voluntarily submitted by these operators contributes immeasurably to the promotion of safety in the mineral mining industries as it discloses the hazards to which metal and nonmetal workers are continually exposed during mineral extractive operations.

Jan 1, 1959

By R. H. Grau, S. B. Robertson, R. B. Krog, T. P. Mucho

Due to the difficulties of ventilating large opening stone mines, the effective dilution of diesel particulate matter and noxious gases has often been problematic. Since stone mines have large openings that develop low air resistances, and propeller fans are designed for low pressure-high volume applications, main mine propeller fans may be a feasible option for ventilating underground stone mines. This paper describes the results of a case study where researchers from the National Institute for Occupational Safety and Health have demonstrated that significant increases in total mine airflow can be achieved and the ventilation improved in a large-opening stone mine by replacing an axial-vane mine fan with two 12-ft diameter propeller fans and adding a line of stoppings. In this study, the use of the propeller fans more than doubled the air quantity from 300,000 cfm to 750,000 cfm, while operating at 50 horsepower less than the original axial-vane fan.

By W. P. Yant, G. W. Jones

"Introduction.During the past two years the Bureau of Mines has conducted a study of natural-gas heaters*** to determine (1) what types of heaters literate carbon monoxide; (2) why carton monocide is liberated; and (3) how, by change of design or construction, the liberation of this gas can be largely eliminated, In addition to the above study the bureau has investigated cases in the Pittsburgh dis¬trict where fatalities have resulted from carbon monoxide given off by natural-gas heaters.Since these fatalities were first brought to the attention of this bureau through the press, it is likely that some cases were missed and thus not listed. On the other hand, some cases reported as being due to carbon monoxide poisoning, on investigation were found to be due to causes other than carbon monoride.The cases listed herein were shown in all probability to be due to carbon monoxide. Those in which there is any doubt have been omitted; so have those in which there was part asphyxiation, where the victims later recovered."

Feb 1, 1924

By James W. Reil

A test series of small, precisely-controlled and thoroughly-monitored production blasts was conducted at two quarries. In each series, all variables except delay were kept constant, as much as practically possible. The first aim of the study was to determine the effect of local geology on ground vibration. The second aim was to test several hypotheses relating the effect of millisecond delay intervals to fragmentation and ground vibration. A resonant frequency of ground vibration was shown to be related to the thickness of the overburden, in accord with a model proposed by Gupta (1961). Since the overburden geology creating this resonant vibration cannot usually be changed, two methods were tested to choose delays such that blast vibrations would destructively interfere. These were shown to be effective in modifying both the peak particle velocity and response spectra of ground vibration. The delay interval chosen also affects fragmentation, primarily in massive rock, with an optimum relief between holes of 2 ms/ft. Strain gage records indicate a possible mechanism consistent with this information.

Jan 1, 1985

By J. J. Forbes

Since 1910 the Bureau of Mines has given training in the care and use of oxygen breathing apparatus under conditions that may exist during mine fires and after mine explosions. In 1929 the Bureau supplemented this instruction by initiating a course in advanced mine rescue training to prepare mine officials and others to organize men for mine rescue and recovery operations. The course of instruction has been developed and expanded since its inception to keep abreast with new ideas, methods, and equipment. Four miners' circulars were issued to be used in the training course. The first of this series (Miners' Circular 33) deals with mine gases and the various methods of detecting them; the second (Miners' Circular 34) gives instructions for sampling and analyzing mine atmospheres; the third (this circular) describes methods and equipment for protection against mine gases; and the fourth (Miners' Circular 36) explains procedures in sealing and unsealing mine fires and in conducting recovery operations, These circulars have been revised from time to time to keep them up to date.

Jan 1, 1954

By Ross W. Smith

Microflotation and surface chemical studies were conducted on a chromite from the Stillwater Complex in Montana and on some of the minerals usually found to be associated with such chromites. Considering the chromite it was found that aging the ground mineral in air or heating it markedly affected its flotation behavior. Much of the observed effects could be attributed to oxidation reactions involving surface chromium and iron species. Strongly acid pretreating the mineral appeared to reverse such effects. Thus, it can be concluded that the manner in which the mineral (or the ore) is pretreated is of utmost importance in its flotation. Work carried out on associated gangue minerals determined how they are likely to behave in a flotation environment and how certain foreign ions derived from a chromite ore itself can affect their surface characteristics and, thus, presumably also their behavior in a flotation circuit.

Jan 1, 1981

By Shail J. Butani

In 1986 the Bureau of Mines conducted a probability sample survey, Mining Industry Population Survey, to measure such employee characteristics as occupation; principal equipment operated; work location at the mine; present job, present company, and total mining experience; job-related training during the last 2 years; age; sex; race; and education. The population estimates are necessary to properly analyze the Mine Safety and Health Administration (MSHA) injury (includes illness and fatality data) statistics; that is, to compare and contrast injury rates for various subpopulations in order to identify those groups that are exhibiting higher than average injury rates. This report uses the survey's results to characterize the U.S. stone mining workforce from March through September 1986. Similar reports have been published for the metallic, sand and gravel, and nonmetallic mining industries, as well as for the entire metal and nonmetal mining (includes metallic, stone, sand and gravel, and nonmetallic industries) sector and the coal mining sector.

Jan 1, 1988

By Stephen H. E. Phillips

This report outlines the modifications that have been carried out to the original prototype rectangular shaft sinking equipment for its use in a circular shaft. The surface testing of the machine is described where seven, 24 ft. diameter shafts were excavated to an average depth of 21 ft. at rates ranging between 1 ft/hr and 1.9 ft/hr depending upon the prevailing conditions. The durability and productivity standards for the equipment were established indicating that the objectives of the project had been realized. That is, when using the machine the sinking rates could be increased by 25% and costs reduced by a corresponding amount compared with conventional drill and blast methods. In addition it was shown that the machine had been developed to a state of fitness for sustained underground use.

Jan 1, 1981