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By R. W. Watson

This Bureau of Mines report summarizes some recent results on the sensitivity of various experimental explosive systems using ammonium nitrate (AN) as the oxidizing agent. The sensitivity survey included drop-weight and friction testing and sensitivity to initiation by projectile impact and a No.8 blasting cap. It was found that certain types of AN prills can result in cap-sensitive mixtures when combined with No.2 diesel fuel (Fa); prilled AN mixed with nitromethane also result in cap-sensitive mixtures. Mixtures of AN prills and neat 1-and 2-nitropropane were not cap-sensitive, and the use of powdered or grained aluminum in AN-FO did not adversely affect the sensitivity except possibly to increase its sensitivity to friction.

Jan 1, 1974

By Larry Joe Linley

The Department of the Interior, Bureau of Mines is reviewing explosion protection methods for use in gassy coal mines. This performance criteria guideline is an evaluation of three explosion protection methods of machines electrically powered with voltages up to 15 000 volts AC. A sufficient amount of basic research has been accomplished to verify that the explosion-proof and pressurized enclosure methods can provide adequate explosion protection with the present state of the art up to 15 000 volts AC. The routine application of the potted enclosure as a stand alone protection method requires further investigation or development in order to clarify performance criteria and verification-certification requirements. An extensive literature search, a series of high voltage tests, and a design evaluation of the three explosion protection methods performed at White Sands Test Facility indicates that the explosion-proof, pressurized, and potted enclosures can all be used to enclose up to 15 000 volts AC, if the performance criteria and verification-certification requirements recommended in this guideline are implemented.

Jan 1, 1982

By A. R. T. Denues

"INTRODUCTION The Explosives Division of the Bureau of Mines, United States Department of the Interior, is investigating cushioned blasting at the Explosives Testing Station, Bruceton, Pa. The general interests of this investigation are practical and relate particularly to safety. The immediate concern is an application of cushioned blasting in coal mining.In cushioned blasting, various means are employed to reduce the intensity of the application of energy in an explosive action in a borehole. The primary object is to increase the efficiency of the use of explosives. Cushioned blasting is designed to save the energy usually lost in excessive shattering and in this way to effect economies and to produce increased proportions of desirable lump coal. That this saving should lead to greater efficiency is indicated by an analogy with the theory and experience of size-redaction by crushing or grinding from which it is known that a large proportion of the energy consumed is expended in producing the smaller sizes (26),3/. Aside from these considerations, increasing the yield of lump coal is important in practice because larger sizes of coal usually sell at higher prices. Some statistics published in England in 1934 (63) illustrate the economic origin of the interest in increasing yields of lump coal; these indicate for three sizes of coal that as the size decreases the value decreases in the approximate series 3:1.5:1, thus:"

May 1, 1940

By John D. Spencer

Clean energy production from coal, oil, and gas, and the development of these and other energy sources continued to be a major objective of the energy research program of the Bureau of Mines.3 In 1971 increased emphasis was placed on the production of fluid fuels and chemicals from coal. Advances were achieved in the development of the Synthane and Hydrane gasification processes for producing pipeline gas from coal (page 31), and progress was made in research on solid wastes utilization (page 2), and on liquid fuels production from coal (page 37); Coal mine safety, solid waste disposal and utilization, coal preparation and transport, and fundamental research on coal and related products also continued to be the subject of extensive research. Improved methods for extracting petroleum and natural gas without surface and subsurface pollution featured research on these vital fuel and energy sources. This research was highlighted by studies of the fracturing systems of reservoir rocks, including subsurface fracture mapping and new fracturing techniques to achieve optimum production of oil and gas (page 52). Of equal importance were projects on oil recovery by water or gas flooding (page 52), by steam injection (page 57), on the identification of oil spills (page 63), and on means to reduce vehicular exhaust emissions (page 66).

Jan 1, 1972

By Alvin Kaufman

To aid industry and Government in planning water developments the Bureau of Mines in 1963 canvassed mineral producers to determine water use in 1962. Water use by the mineral industry comprises only 2 percent of the water withdrawn by industry as a whole. The major water-using mineral industries are natural gas processing, phosphate rock, sand and gravel, and iron ore. Analysis indicated the following conclusions: 1. Total water use and new water intake is dependent on the quantity of material processed and the process water requirements of the particular industry or commodity. 2. Recirculation is dependent on the processing requirements of a particular commodity, the manner in which the water is used, cooling and condensing requirements in certain large industries, the quality of new water intake, and the need to treat new and discharged water. 3. Consumed water is dependent on the quantity of water recirculated, the temperature and humidity in the area, and the proportion of water used for cooling and condensing. 4. A threefold increase in water use by the mineral industry by 1985 is forecast

Jan 1, 1966

By Masami Hayashi

The Bureau of Mines conducted laboratory studies to investigate methods for desilicating sodium aluminate solution derived from leaching a limestone-anorthosite sinter with 10-pct Na2C03 solution. Desilication tests were made at atmospheric pressure to determine the effects of time and additions of lime and desilication residues. A two-stage, countercurrent desilication procedure was developed to reduce the Si02 content sufficiently to meet specifications for cell-grade A1203. Both stages were conducted at boiling temperatures at atmospheric pressure. Reagent lime was charged as desilication seed to the partially desilicated solution in the second stage, and a product (desilication residue) precipitated by the lime addition was charged to the freshly leached solution in the first stage. Average A1203 loss in the desilication circuit was 5.8 pct, and the product solution contained less than 0.04 g/l Si02. Complete precipitation of A1203 by carbonation resulted in a hydrate containing less than 0.01 pct Si02. Calcination of this hydrate would produce A1203 meeting the 0.015 pct Si02 specification for cell-grade material.

Jan 1, 1982

By G. M. Martinez

The Bureau of Mines has investigated methods for the recovery of byproduct heavy minerals from sand and gravel operations in Oregon and Washington. These heavy minerals are not currently recovered except for gold in a few areas. The recovery of byproduct heavy minerals would provide a domestic source of minerals presently imported, and a more efficient use of domestic resources would be accomplished. Samples from more than 40 locations were treated by gravity separation to yield heavy mineral concentrates (black sands). Magnetite, ilmenite, zircon, rutile, chromite, platinum-group minerals, radioactive minerals and gold were identified in the concentrates. Individual zircon, ilmenite, chromite; magnetite, and gold products were recovered from selected concentrates by low-and high-intensity magnetic, high-tension, and heavy-medium separation techniques. The recovery for the individual mineral products ranged from 67 to 95 pct.

Jan 1, 1981

By John C. Machisak

INJURY experience and employment data at all metal mines in the United States and Alaska are presented in this Information Circular for the calendar year 1958. This publication covers the metal mining industries, and contains statistical data on injuries and employment pertinent to metal mines, ore-dressing plants, and primary nonferrous smelters, refineries, and reduction plants. These operations report injury and employment information annually to the Bureau of Mines on a voluntary basis. The Bureau is authorized to make requests for such data, and the information submitted contributes immeasurably to the promotion of safety in the metal mining industry. Every effort has been made to make the annual canvass as complete as possible. This publication contains, along with production and development workers, the office employees at the mine location. The metal mines identified in this publication are classified according to the mineral ores mined; that is, copper, iron, lead-zinc, gold-silver lode, gold placer, and miscellaneous metals.

Jan 1, 1962

By J. B. Gayle

The Bureau of Mines studied the effects of air oxidation on the recovery of float coal. Both batch-and continuous-type tests were made on six bituminous coals, representing the range in rank of coals now commercially used for carbonization, and on one anthracite coal. The effects on flotation recovery of oxidation at 1000 C for periods up to 50 days were investigated using an alcohol-type frother and a kerosine-pine oil reagent. Two series of release analysis tests were made, using one medium-volatile bituminous coal. Float coal recovery was adversely affected by oxidation in all tests where the alcohol-type frother was used. Conversely, a small degree of oxidation improved recovery with kerosine-pine oil frother for some of the coals in continuous tests. Prolonged oxidation (beyond about 14 days) adversely affected float coal recovery for all coals, the effect being more pronounced for batch-type tests and for tests using alcohol-type frother. Reagent selectivity for the rejection of both ash forming and sulfur bearing minerals was reduced by oxidation. Severe reduction of reagent selectivity required only about 3 days' oxidation for alcohol-type frother but more than 10 days' oxidation when the kerosene-pine oil reagent was used.

Jan 1, 1965

By D. R. Tweeton

The U.S. Bureau of Mines has developed tomographic computer programs for geophysical applications and is distributing them as part of a Bureau plan to facilitate the transfer of technology to potential users. These programs were developed for predicting and monitoring the flow pattern of leach solution during in situ mining. The Bureau has also applied them to assessing high-wall blast damage and examining the integrity of mine-related geological structures. This report describes the curved ray program BOMCMTR (Bureau of Mines curved ray tomographic reconstruction), tells how to run it, and gives examples with synthetic and field data. BOMCRATR provides optional mathematical constraints to counteract the nonuniqueness of tomographic reconstructions with crosshole data. These constraints include limiting the maximum and minimum velocities, fixing the velocity at any point to any value, and establishing layers in which velocity does not vary with horizontal position. The user can test for nonuniqueness by varying the initial velocity pattern, The program can perform either curved or straight ray analysis. Ray paths are calculated analytically in triangular pixels, which is faster than incremental numerical approximations,

Jan 1, 2010

By Roger L. Baer

Marine disposal of mill tailings has been practiced worldwide for over a century. However, only recently have the environmental effects of marine disposal been systematically studied. Some early attempts at marine disposal of tailings resulted in adverse impacts to marine life. However, recent advances in tailings disposal methods have included the introduction of engineered submarine tailings discharge systems, advanced environmental assessment and monitoring methods, and oceanographic modeling systems. Successful submarine tailings disposal (STD) has occurred at several mines. The U.S. Bureau of Mines (BOM) has undertaken studies of the disposal of mining and milling wastes in the marine environment. The BOM Alaska Field Operations Center, Juneau, initiated a review of the technology, regulations, and economic aspects of STD. The review illuminated the need for organization of literature on the subject, therefore the Bureau compiled this extensive bibliography on marine disposal of mill tailings. The bibliography presented here contains 1483 references and is also available through diskette in the Word Perfects format. A review of the references indicates that literature on submarine disposal inadequately covers the subject. The majority of the references listed only peripherally relate to the subject. Published literature on the engineering and environmental aspects of STD is severely limited.

Jan 1, 2011

By J. M. Goris

The U.S. Bureau of Mines is conducting research on cable bolt ground supports to assess their material and support properties, to provide design criteria for using cable bolt supports as roof control systems under various types of underground mining conditions, and to develop a mathematical model of cable bolt support systems. Part 1 described laboratory studies of the support properties of conventional steel cable bolts. Part 2 describes the strength characteristics of conventional cables with steel buttons, single and double birdcage cables, and epoxy-coated cables.

Jan 1, 1991

By Howard E. Rollman

South Central United States, an area including Arkansas, Kansas, Louisiana, Mississippi, Missouri, Oklahoma, and Texas, is a net exporter of refractories. Nearly $45 million of these materials was shipped in 1954 from plants in the area, compared with area consumption of $18.5 million. About 88 percent of all refractories production is concentrated in Missouri. The prevalent consumption pattern, however, is one of localized shortages. For example, although Texas uses more than half of the refractories consumed in the South Central United States, production of refractories in Texas is relatively small. Also, the apparent self-sufficiency of the area is in terms of value produced rather than in terms of products consumed. Nearly all of the $6,425,000 nonclay refractories consumed in the area were shipped from other States. Local resources possibly could be developed for making refractories to serve markets that currently are being supplied from outside the area. Since other industries are growing rapidly in the area, the market for refractories is expected to continue to grow--more rapidly than the national market. The Missouri refractories industry is economically important nationally. Nearly one-fourth of the clay refractories produced in the United States are made in Missouri. Moreover, Missouri produces most of the higher grade clay refractories, about 62 percent of the high-alumina refractories, and 85 percent of the superduty refractories. The competitive position of the Missouri refractories industry is strong. The national market for clay refractories and the market in the South Central United States are expected to continue to grow. The ratio of net income to the value of refractories shipped in Missouri is larger than the national average.

Jan 1, 1960

By R. S. Dean

The possibility of cheap electric power for a number of mining areas in this country has suggested to many the idea of electric smelting of nonferrous ores in small units at or near the mines. The electric smelting of nonferrous ores was tested fairly thoroughly 20 years ago by United States Bureau of Mines and by others, and the fact that it did not achieve continuing workable success in any instance is sufficient proof that it offered no advantages at that time.

Jan 1, 1937

By Pedro Lilienfeld

This report describes the development, design, fabrication and testing of a port-able, battery-operated, light scattering monitor (henceforth to be designated as ILSDM) for the rapid measurement of the concentration of respirable dust in mining environments. This instrument incorporates state-of-the-art design characteristics and makes use of advanced solid-state components both for light emission as well as for its detection. The use of a pulsed light source combined with synchronous signal detection minimizes drift problems and optimizes the sensitivity of the measurement. Simplicity of operation, reliability and ruggedness, light weight as well as improved performance were salient objectives of this instrument development program. Continuous clean-air flow screening of all critical optical surfaces, and optimized optical detection and electronic signal processing design resulted in about a hundred-fold decrease of noise and drift with respect to precursor instruments. Equivalent mass concentration measurements 88 low as 10 micrograms per cubic meter can be routinely performed with time constants of about 2 second.

Jan 1, 1979

The objective of this handbook is to provide the inspector with guidance for recognizing hazards from inhalation contaminants in above ground work areas of underground and surface coal mining and processing facilities and evaluating these hazards by collecting samples or making field determinations and interpreting the analytical results. There are several portions of the handbook which should prove most useful to the inspectors. The names and locations of these portions are listed below: Survey Check List (Page 2-3) Rules for Determining if Sampling is Required (Page 2-1) List of Most Frequently Encountered Contaminants (Page 2-2) List of Candidate Contaminants and their Sampling Conditions (Table 2, Starting on page 2-5) Interpretation of Results (Page 2-16) Procedure for a, Health and Safety Inspection (Page 2-25) For obtaining information not available from the above mentioned portions of the handbook, the inspector is directed to the Table of Contents, the Glossary of Terms, and the List of Commercial Products Encountered in Surveys.

Jan 1, 1975

By Stanley M. Walker

Safety consciousness is not a constant for which a specific value can be assigned, but is a variable, which is frequently intangible. Its evaluation is not simple. We all know that safety consciousness is the most potent factor in the prevention of accidents. Safety consciousness may be defined as awareness of hazard and alertness to danger, which controls every action of an individual through his desire to remain alive and uninjured.

Jan 1, 1951

By J. C. Dumbrille

The following account of wining practices of the Kirkland Late Gold twining Co., (Ltd.), at Kirkland Lake, Ontario, is one of 4 series of papers being prepared by the United States Bureau of Mines on mining practices, methods, sad costs in various districts. The author has prepared this paper with the help and permission of J. B. Tyrrell and W. M. Sixt, the managing director and the mine manager, respectively. This mine is operating at a daily rate of about 150 tons.

Jan 1, 1931

By T. R. Jolley

This publication describes the control of fires in inactive coal deposits in the Western United States, including Alaska by the Bureau of Mines. Material presented should contribute to a better understanding of the purpose, process, and benefits of the program. Forty fires were extinguished or controlled in the Western United States and Alaska from 1948 to 1958 under a national program directed by the Bureau's Health and Safety activity. Thirty-five fires were controlled by smothering; three were controlled by the isolation method; and two were extinguished by removing the burning coal, smothering it with incombustible material, and backfilling the fire zone. The fire-control projects were distributed as follows: Alaska 2, Arizona 1, Colorado 9, Montana 9, New Mexico 4, Utah 2, and Wyoming 13. The total cost of the 40 fires extinguished or controlled was $1,203,957. Of this cost, 12.8 percent was engineering and administrative and 87.2 percent was contractual services.

Jan 1, 1959

By R. E. Simpson

Beginning in 1972, fully grouted resin bolts were used in underground mines. An estimated 20 million resin bolts will be installed in 1980 owing to their apparent support improvement in most roof-bolt applications. Inorganic cements were tested to replace the resin at a lower cost while retaining the advantages of a grouted bolt. Although other inorganic materials were considered, all but portland and gypsum cements were rejected for reasons of availability, performance, or cost. Portland and gypsum-type cements were tested by the Bureau of Mines to select a fast-hardening, low-cost material that would anchor a roof bolt adequately to meet safety standards. An alpha-gypsum cement, accelerated with potassium sulfate, was selected as the best material because it had adequate pull strength at a desired set time of less than 5 minutes and was readily available.

Jan 1, 1980