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By Stella Sigler

This publication contains analyses and related source data for 153 natural gas samples from 16 States. Of the total samples, 149 were collected during calendar year 1993. The remainder were collected earlier, but releases granting permission to publish were not received until 1993. None of the analyses have been previously published in annual reports. All samples were obtained and analyzed as part of U.S. Department of the Interior, U.S. Bureau of Mines investigations of the occurrences of helium in natural gases of countries with free market economies. This survey has been conducted since 1917. The analyses published herein were made by mass spectrometer and chromatograph.

Jan 1, 1994

By H. F. Yancey

The Baum-type jig used so widely to clean bituminous coals has not been adopted for anthracite. If proved suitable for anthracite, its use might lower preparation costs in some plants. Cleaning trials on a Pennsylvania anthracite in a laboratory-size Baum-type jig were undertaken by the Bureau of Mines to provide indicative information that would be helpful in determining whether the cost of a full-scale installation would be justified. Clean coal surpassing standard anthracite specifications was obtained in all sizes from Stove through No. 5 Buckwheat. Recovery effi¬ciencies were acceptable down to 3/16-inch size, but there was excessive loss of coal in the finer sizes. Thus the fine refuse produced in a commercial plant might re¬quire retreatment. A comparative cleaning trial in a dense-medium pilot plant provided a recovery efficiency only l percent higher than obtained in jigging.

Jan 1, 1957

By L. Kaufman

Fifteen boride composites were synthesized by hot pressing and evaluated by physical and incendivity testing as non-sparking tool materials. The incendivity tests, conducted at the U. S. Bureau of Mines, Albany Research Center, compared the boride compo-sites with standard cobalt-bonded tungsten carbide material used for coal cutter bits. Two titanium diboride composites and two zirconium diboride composites out-performed cobalt-bonded tungsten carbide in wear resistance and reduced tendency to cause ignitions. However, three of these candidates exhibited undesirable chipping. The remaining candidate, a TiB2-(Ni, Cu) composite, did not chip, nor did it cause ignitions at levels where cobalt-bonded tungsten carbide tools caused ignitions in the incendivity tests. Thus, this material appears to be a logical candidate for further development.

Jan 1, 1973

By M. O. Magnuson

This publication describes abandoned-mine fire-control work administered by the Bureau of Mines under cooperative agreements with State and local governments. The work was done by private contractors under the supervision of Bureau engineers. The work is authorized by Public Law 738, approved August 31, 1954, and Public Law 89-4, approved March 9, 1965. Earlier work was authorized by Interior Department Appropriations Acts for fiscal years 1949-55. A total of 70 fires have been controlled under this program in the eastern bituminous region. The nature and extent of the abandoned-mine fire problem in the bituminous region is discussed, and the methods used for controlling these fires are described. The methods that have been used, either singly or in combination, include loading out and cooling the burning material, installing fire barriers, surface sealing, and water and pneumatic flushing.

Jan 1, 1974

By Richard H. Spencer

Since the passage of the Coal Mine Health and Safety Act of 1969, the Bureau of Mines has made many advances in mine communications. These efforts have resulted in the following developments and demonstrations: Surface-to-surface electromagnetic transmission of baseband voice signals through overburdens as deep as 600 feet. This transmission was achieved with equipment from the Interim Mine Rescue and Survival System Program, and demonstrated that baseband voice communications could be obtained through these overburdens in the absence of mine-generated noise; that is, when the mine power system was shut off, However, during mine operational conditions, the mine-generated noise proved to be so large that effective baseband voice communications to the desired depths could not be effected.

Jan 1, 1975

A knowledge of the mechanics of wave propagation through the earth is essential if reliable communication systems are to be designed for coal mine environments. To obtain a reliable basis from which accurate propagation predictions could be drawn, a series of theoretical studies have been prepared for the US Bureau of Mines by Mr. Ramsay Decker of Spectra Associates, Inc. through a subcontract with Collins Radio Group. These reports formulate the analytical techniques from which we may derive frequencies and antenna configurations that yield the optimum signal-to-noise ratios over the greatest distances in mine environments. The reports of sections 2 and 4 deal with analytical techniques for determining the signal-to- noise ratio within a mine environment for loop-to-loop and line source-to-loop antenna con- figurations. The analytical results of these reports were then implemented into computer programs to obtain predictions concerning through-the-earth signal propagation. These preliminary predictions are based on noise data compiled by Bensema, Maxwell and Stone, and WVU prior to the extensive research conducted by the National Bureau of Standards (NBS). These initial measurements indicated a 20- to 30-dB lower noise level than that measured recently by NBS. The recent NBS data is that used by Collins in the final predictions. The following outline indicates the order and subject matter treated in the subsequent sections: Section 2 - Signal-to-Noise Analysis for Loop-to-Loop Mine Communications Section 3 - The Horizontal Electric Dipole Section 4 - Signal-to-Noise Analysis for Down-Link Line Source Mine Communications Section 5 - LF Communication Section 6 - The Application of Recent NBS Noise Data to Mine Communications Section 7 - Analysis of Mine Communication Propagation Programs

Nov 15, 1974

By B. W. Madsen

The Bureau of Mines conducted a large-scale (6.4 t), long-term (2,165 days) test to gain a better understanding of the leaching characteristics of chalcopyritic ores. An ore sample containing 0.77 pct Cu was leached in a fiberglass column by downward percolation of acidified ferric sulfate solutions. Three sets of leaching conditions were investigated: (1) ambient temperature leaching, (2) elevated temperature (50° to 60° C) leaching, and (3) elevated temperature leaching after inoculation with thermophilic bacteria. Leaching at ambient temperature resulted in a copper extraction rate of 0.44 pct per 100 days. Increasing the temperature to 50° to 60° C resulted in decreased activity of natural mesophilic bacteria, and the leaching rate decreased to 0.22 pct per 100 days. The pH was lowered from 2.0 to 1.6, and nutrient solutions that contained thermophilic bacteria were added. This procedure resulted in an increase in the ferric-to-ferrous iron ratio and an increase in the copper leaching rate. However, the increased leaching rate was not sustained, and 120 days after inoculation the bacterial activity declined, the ferrous iron content increased, and the copper leaching rate decreased.

Jan 1, 1983

By Susan Brink

The U.S. Bureau of Mines is investigating the potential of in situ leach mining a variety of Cu, Mn, and Au-Ag ores. Geologic characterization of ore samples from laboratory leaching experiments is conducted both prior to and after leaching to assess the effects of leaching on the chemistry, mineralogy, and texture of the rocks. The identification and chemical compositions of ore, gangue, and reaction products are determined by a combination of techniques such as reflected and transmitted light microscopy, X-ray diffraction, electron diffraction, electron microprobe analysis, and backscattered electron imaging with scanning electron microscopy. The distribution of the desired metal in various mineral phases can be illustrated using elemental X-ray maps. The potential of reactive gangue minerals to rob Cu from leach solutions is investigated with the aid of transmission electron microscopy. Porosity and permeability are measured to determine how effectively the host rock can transmit leach solution. Textural relationships between ore, gangue, secondary reaction products, and fluid channelways are determined by petrographic examination and are documented by optical photomicrographs and secondary electron imaging. Representative sample selection is described, and several epoxy impregnation and sample mounting techniques are discussed.

Jan 1, 1991

By Nabil A. Bibawy

An improved method for preparing gravimetric standard gas mixtures of helium-4 in nitrogen has been developed by the U.S. Bureau of Mines. A single-pan 12-kg analytical balance that has a sensitivity of 3 mg is used to prepare the mixture. The balance will accommodate a cylinder having a volume of approximately 4 L that weighs approximately 5 kg. The method has been improved to a precision of ±O.04 pct by performing four successive dilutions, by improved handling of gases in the manifold, and by using an improved analytical method to select high-purity gases.

Jan 1, 1990

By G. A. Smyres

The Bureau of Mines conducted laboratory studies to determine the feasibility of chlorine-oxygen leaching for treating low-grade zinc sul-fide flotation concentrates. Recovery of zinc sulfides by flotation from complex fine-grained sulfide ores is substantially higher in low-grade bulk sulfide concentrates than in the high-grade cleaned concen-trates required for smelter feed. However, there is no commercial process in the United States for the treatment of low-grade bulk zinc sul-fide concentrates. Leaching experiments using reactors of 500-mL and I-gal capacity were conducted on a bulk concentrate containing 19.3 pct Zn, 35.6 pct Fe, and 39.4 pct S. The effects of pressure, temperature, and percent solids on extraction were investigated. The chlorine-oxygen leaching procedure showed promise for treating the concentrates. Zinc extractions of 95 pct or more were obtained by leaching at 50 pct solids in the temperature range of 1000 to 1200 C. Zinc extractions by leaching with chlorine followed by oxygen at reactor pressures of 50 to 100 psig were independent of pressure.

Jan 1, 1985

By O. C. Blade

The southeastern region of the United States is becoming more important as a petroleum-producing area, and it is receiving increasing attention from oil operators. In 1948 total production of crude oil from six southeastern States - Alabama, Florida, Kentucky, Mississippi, Tennessee, and Virginia - was 55,244,000 barrels, which represents 2.7 percent of the Nation's output during that year. Kentucky and Tennessee have produced crude oil since the early days of the industry, but the remaining four States have had production only few years. Data on annual production of crude petroleum in the six States are given in table 1.

Jan 1, 1950

By Michael Sokaski, M. R. Geer, H. F. Yancey

This report is one of a series describing investigations by the Federal Bureau of Mines of the performance of various types of coal - cleaning equipment ; other reports in the series are listed in the bibliography . The information in these reports is useful to the coal industry and the manufacturers of coal - cleaning equipment in several ways : First , it assists the coalpreparation engineer who is planning a new plant to select the type of process best suited to the requirements by enabling him to forecast the yield and quality of clean coal obtainable with each type of equipment . Second , the information serves as a yardstick by which the performance of a plant can be judged and thus helps determine whether it is operating at satisfactory efficiency . Both these functions promote better coal - preparation practice ; that is , they help provide coal of more suitable quality for the market and likewise minimize the waste of good coal . This serves the interest of conservation with which the Bureau is vitally concerned . The present report deals with three plants using the Tromp dense - medium process , named after its inventor , K. F. Tromp , who developed the process in the Netherlands in 1936.5/ Selection of this particular dense -medium process for investigation was entirely a matter of convenience , and reports dealing with other dense -medium systems are planned for the future . Two baths are employed in one of the plants investigated . The first of these , handling 6- to 3 - inch coal , exhibited an exceptionally sharp separation between coal and impurity . This was characterized by an error area of 12 and a probable error of 0.023 . In the second bath , treating refuse from the

Jul 1, 1960

By Tilman M. M.

The effects of substituting cobalt for nickel on the acid corrosion resistance of two types of austenitic stainless steel were determined. Cobalt substitutions to a maximum 2.2 weight-percent were made in types 302 and 309 stainless steels. Total immersion corrosion tests were made in 10 volume-percent hydrochloric acid, and boiling-acid tests were conducted in 65 weight-percent nitric acid and in undiluted glacial acetic acid. For modified type 309 in acetic acid, corrosion rates decreased for additions greater than 0.57 weight-percent cobalt. Corrosion rates increased as cobalt was increased up to about 1 weight percent for modified type 302 in nitric and hydrochloric acids and for modified type 309 in nitric acid, but these rates decreased with a further increase in cobalt content. A gradual increase in corrosion rates with increasing cobalt content was shown for type 302 in acetic acid and for type 309 in hydrochloric acid. Cobalt substitutions in larger amounts (above a ratio of 8 Ni to 1 Co) may increase the corrosion resistance of the austenitic stainless steels.

Jan 1, 1965

By L. M. Demers, D. C. Kuhn

It has been suggested that radicals on the surface of dust particles are key chemical factors in the pathophysiology that results from the occupational inhalation of coal and silica dust. In addition, oxygenated derivatives of arachidonic acid (eicosanoidsJ have been implicated as important biochemical mediator5 of mineral dust-induced lung disease through their role in bronchial and vascular smooth muscle reactivity, inflammation, and fibrosis. Therefore, we assessed eicosanoid production by the rat alveolar macrophage (AM) exposed in vitro to mineral dusts with varying surface chemical characteristics in order to determine if radicals associated with the mineral dust could influence the production of proinflammatory mediators in the lung environment. Primary cultures of rat AM were exposed to freshly fractured or "stale" bituminous coal dust, as well as untreated silica or silica calcined to 500 and 1100°C. Prostaglandin E1 (PGE;V, thromboxane Ai (T}(Ay, and leukotriene 84 (LTB; levels in incubation medium were determined by specific radioimmunoassay. When AM were exposed to freshly fractured coal dust, PGE2 production was markedly increased. In contrast, exposure of AM to "stale" dust significantly reduced PGE1 production. Exposure of AM to freshly fractured coal dust resulted in a significant increase in production by AM, while exposure to stale coal dust did not influence AM TXA1 production. Neither "fresh" nor "stale" coal dust had any effect on LTB4 production. In vitro exposure of AM to untreated silica resulted in a significant increase in TXA1 PGE.,, TXA; and LTB4 production compared with control. However, exposure of AM to silica calcined to 11oo•c resulted in eicosanoid levels that were not significantly different from control. These effects were still apparent 8 wk after calcination of the silica particles. Silica was a more potent activator of AM eicosanoid production than was coal, and amorphous fumed silica was a more potent activator of AM eicosanoid production than was crystalline silica. These findings suggest that radicals associated with respirable coal and silica particles may play a key role in the ability of mineral dust to activate AM eicosanoid production and therefore may be important in the pathophysiological consequences of occupational mineral dust inhalation.

Mar 1, 1992

By Joseph B. Cummings

The Twin Buttes camp embraces eight mines in the Pima mining district. The first mining claims in the camp are said to have been located in 1876, but little mining was done until 1905. Intermittent operation of five of the mi.nes to 1928 yielded 388,231 tons of ore averaging 6.19 percent copper and 8 small tonnage of high-grade oxidized zinc ore. While the Bureau was investigating the area, one mine was active, and it started to produce in 1944. The mines of the Twin Buttes camp are at or near contacts of intrusive granite with Paleozoic limestones and quartzite. The ore shoots lie in metamorphosed sediments adjacent to a zone of garnet rock that separates the ore from the footwall granite. Small fissures that originate at the contact and cut the sedimentaries appear to have been controlling factors in ore deposition. No important ore bodies are exposed at the surface, and those developed wore discovered by sinking on the fissure veins to the contact zone. Most of the area overlying the favorable ore zone is covered by alluvium ranging in thickness from 5 to more than 20 feet.

Jan 1, 1950

By Paul M. Linebarger

This paper is one of a series of digests of foreign mining legislation and court decisions prepared in advance of a general report relative to the rights of American citizens to explore for minerals and to own and operate mines in various foreign countries. This interpretation of the laws of Mexico has been pro oared from the best information available in Washington but is released subject to correction and amplification, if necessary, by the proper American diplomatic and consular officers, to whom it has been referred through the courtesy of the Department of State. INTRODUCTION Present-day Mexican mining legislation involves, not only the latest minim enactment (August 1, 1026), but many other enactments and regulations, principal among which are the Constitution, the Civil Code, the Code of Commerce, the Foreign Law, the Mining Tax Law, and. the Civil Jurisprudence of Mexico--the last-mentioned being based in Dart on Supreme Court decisions. Ere Mexican Federal Government is supreme in mining legislation because, among other reasons, a large part of the revenue of the Government must come from the fiscal control of the mines. All circulars, decrees, and rulings that affect the mines not only have their origin in the Central Government but are administered thereby. The Department of Industry, Commerce, and Labor is in control of all mines. Attention may here be called, however,

Jan 1, 1929

By Donald W. Mitchell, John Nagy, Edwin M. Murphy

"Investigations in the Federal Bureau of Mines Experimental coal mine near Pittsburgh, Pa., have shown that high-expansion foam containing at least 0.2 ounce of water per cubic foot of volume is effective in controlling exper-imental underground coal, oil, or wood fires. Some of the fires were extinguished, but more of the coal and wood fires were brought under enough control to permit direct attack with water or other extinguishing agent or loading the hot material into cars. The largest controlled experimental fire, which burned about 5 hours before attack, was in a coalbed 5 feet wide, 10 inches thick, and 100 feet long. The greatest distance foam was transported to control a fire was 1,010 feet.An incipient fire should be attacked promptly with water, rock dust, or other approved and readily available extinguishing agents. Where heat, roof falls, and smoke prevent direct approach, the more involved procedure of using foam may be advantageous. The effectiveness of the foam in controlling a deep coated fire of considerable extent H,vet to be proved by actual trials in aSome hydrogen, carbon monoxide, and methane gases are generated when a fire is attacked with foam. Calculations showed that in experimental fire tests an explosive mixture could form; however, this would occur only within a narrow range of combustible gas-air mixtures not likely to be found in practice. The principal explosion hazards are due to generation of gases by the foam, localized build-up of normally liberated methane, and volatiles liberated by the coal during heating. The quantity of combustible gases generated by the action of the foam on the fire is about the same as that when an equivalent amount of water is applied."

Mar 1, 1960

By Jürgen F. Brune, R. Karl Zipf, Michael J. Sapko

Seals are barriers constructed in underground coal mines throughout the United States to isolate abandoned mining panels or groups of panels from the active workings. Historically, mining regulations required seals to withstand a 140-kPa (20-psig) explosion pressure. However, the Mine Improvement and New Emergency Response Act (“MINER Act”) requires the Mine Safety and Health Administration (MSHA) to increase this design standard by the end of 2007. This report provides a sound scientific and engineering justification to recommend a three-tiered explosion pressure design criterion for new seals in coal mines in response to the MINER Act. Much of the information contained in this report also applies to existing seals. Engineers from the National Institute for Occupational Safety and Health (NIOSH) examined seal design criteria and practices used in the United States, Europe, and Australia and then classified seals into their various applications. Next, the engineers considered various kinds of explosive atmospheres that can accumulate within sealed areas and used thermodynamic calculations and simple gas explosion models to estimate worst-case explosion pressures that could impact seals. Three design pressure-time curves were developed for the dynamic structural analysis of new seals under the conditions in which those seals may be used: unmonitored seals where there is a possibility of methane-air detonation or high-pressure nonreactive shock waves and their reflections behind the seal; unmonitored seals with little likelihood of detonation or high-pressure nonreactive shock waves and their reflections; and monitored seals where the amount of potentially explosive methane-air is strictly limited and controlled. Figure 1 is a simple flowchart that illustrates the key decisions in choosing between the monitored or unmonitored seal design approaches and the three design pressure-time curves. For the first condition, an unmonitored seal with an explosion run-up length of more than 50 m (165 ft), the possibility of detonation or high-pressure nonreactive shock waves and their reflections exists. The recommended design pressure-time curve rises to 4.4 MPa (640 psig) and then falls to the 800-kPa (120-psig) constant volume (CV) explosion overpressure. For unmonitored seals with an explosion run-up length of less than 50 m (165 ft), the possibility of detonation or high-pressure nonreactive shock waves and their reflections is less likely. A less severe design pressure-time curve that simply rises to the 800-kPa (120-psig) CV explosion overpressure may be employed. For monitored seals, engineers can use a 345-kPa (50-psig) design pressure-time curve if monitoring can ensure that (1) the maximum length of explosive mix behind a seal does not exceed 5 m (16 ft) and (2) the volume of explosive mix does not exceed 40% of the total sealed volume. Use of this 345-kPa (50-psig) design pressure-time curve requires monitoring and active management of the sealed area atmosphere. These design pressure-time curves apply to new seal design and construction.

Jan 7, 2007

By F. S. Kendorski

This report covers the work on developing criteria for determining when a hazard exists when mining stratified mineral deposits beneath bodies of surface water. The nature of water bodies is considered, the disturbance to the strata induced by mining is described, inundation case histories reviewed, reasonable water inflows derived, and methods of mining to prevent or minimize the hazard are presented. Criteria are given whereby effected industries and agencies can recognize a potential hazard and plan a mine accordingly, releasing considerable mineral reserves otherwise considered unminable.

Jan 1, 1979

By R. O. Dannenberg

Exploratory research was conducted to ascertain the feasibility of recovering beryllium from Spor Mountain, Utah, ore by the sodium fluosilicate (Na2SiF6) method used industrially for processing beryl. Na2SiF6 requirements to form water-soluble salts of beryllium were determined for three different samples--two clayey ores containing 0.6 and 1.3 pct BeO, respectively, and a calcareous ore containing 0.6 pct BeO. The ores were sintered with Na2SiF6 at 750° C for 3 hours. About 80 pct of the beryllium was rendered water soluble by sintering the 0.6-pct BeO ores with 30 and 40 lb Na2SiF6 per lb BeO contained in clayey and calcareous ores, respectively. The higher grade 1.3-pct BeO clayey ore required only 20 lb Na2SiF6 per lb BeO to solubilize over 80 pet of the beryllium. As the 0.6-pct BeO clayey ore was possibly the most representative of the deposit as presently delineated, leach liquor prepared from this sample was treated to recover beryllium salts. About 60 pet of the beryllium contained in the ore was recovered as beryllium hydroxide, which then was calcined to yield a 99-pct BeO final product by means of the following operations: (1) Sintering with Na2SiF2, (2) leaching with water, (3) precipitating crude Be(OH)2 by adding NaOH, (4) filtering to separate the hydroxide from the NaF solution, (5) redissolving the crude Be(OH)2 in excess NaOH, (6) filtering to reject caustic-insoluble impurities, and finally (7) boiling the Na2BeO2 filtrate from (8) to precipitate pure Be(OH)2. Reagent consumption was 49 lb Na2SiF6 per lb BeO recovered and 17 lb NaOH per lb BeO.

Jan 1, 1963