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By W. E. Miller, G. S. Scott, G. W. Jones

"INTRODUCTION One of the major activities of the Bureau of Mines is the promotion of safety in mining and the mineral industries. Research is undertaken in connection with these problems to determine the explosion and ignition hazards of combustible gases, liquids, and solids and to investigate means of reducing them.Occasionally the Bureau is asked to determine inflammability or ignition temperatures to enhance safety in nonrnineral industries. From time to time it has complied with such requests when no other agency was available to do the work and the investigation could be conducted with a minimum of time and expense. The present investigation is one of this class.Nicotine (C10H14N2), a colorless combustible liquid having a boiling point of 246°C, is usually obtained from tobacco and its products by extraction processes. When heated to its boiling point it decomposes; the purified product is obtained from tobacco extractions by distillation at reduced pressures or is distilled in a current of inert gas.It has an unpleasant odor, a burning taste, and in the undiluted state is highly toxic. Under certain conditions it can be oxidised to nicotinic acid and in the near future may therefore become of considerable economic importance. Nicotinic acid is a component of the vitamin B complex now commonly used to fortify white flour and other foods that normally are deficient in these vitamins."

May 1, 1942

"An active list of permissible explosives was published in September 1935 as part of United States Bureau of Mines Report of Investigations 32S6, under the title ""Active List of Permissible Explosives and. Blasting Devices Approved. Prior to July 31, 1935."" This list included 154 brand names,Changes in the list that have been authorized subsequently placed 24 addi¬tional brands of permissible explosives on the active permissible list as a re¬sult of tests, changes in brand names, or transfer from the inactive list. Eight permissible explosives were transferred from the active to the inactive list. The present active permissible list contains 170 brand names. The brand names of the permissible explosives placed on the active list are as follows:Black Diamond Nu-Gel No. 4 By test.Black Diamond Special A,do.Burton 11, L. F. By change in name,Burton G, L. F. By test.Columbia B By change in name.Columbia C Do.Columbia D Do.Columbia E Do.Columbia. F Do.Columbia G Do.Columbia 1 Do.Columbia 2 D.Columbia 3 DoColumbia 4 Do.Columbia-Gel 1 Do.Columbia-Gel 2 Do.Genite 5, Do.Genite 7, Do.Genite G Do.Lump Coal C By test.Peerless No, 1 By transfer from inactivePeerless No. 8, L. F. Do.Tri-State Special No. 1 Do.Unilite No. 2 Do."

Dec 1, 1936

By James J. Olson

The Bureau of Mines recorded both particle accelerations and velocities from one-stick and production blasts at Eagle-Picher Industries' Shullsburg mine, Shullsburg, Wis., to test the effectiveness of square root scaling in grouping underground blast vibrations and to determine the effects of rock type and mine geometry on blast vibrations. Although the charge weights of subsequent delay periods sometimes exceeded the charge weight of the zero-delay period, both acceleration and velocity records showed that the zero-delay portion of the Shullsburg production blasts produced the highest vibration amplitudes. Because of the restricted range of charge weights in the Shullsburg experiments, no statistical determination of an appropriate scaling factor could be made. However, the square root scaled peak particle velocity data from the Shullsburg production blasts grouped well within the approximate band-width of vibration data obtained by the Bureau from quarry blasts in many different rock types. This indicates that scaling by some factor, perhaps the square root or cube root of the charge weight, may be an effective way to group and study vibration data from underground blasts. Further research is needed to determine which scaling factor is best for underground blasting.

Jan 1, 1970

By C. C. Shale

Electrical resistivities for various coal ashes in air and in a nitrogen atmosphere are given over the range 100° to 1,500° F. Resistivity of low-carbon ash in air is very high at low temperature, rises to a maximum at about 250° F, decreases very rapidly with increasing temperature to about 800° F, then decreases gradually to approach an asymptote at 1,500° F. Resistivity of high-carbon ash in air follows this same general trend at values which are much lower and are proportional to the carbon content. After the carbon has been burned off, resistivity of the remaining ash approaches the high values corresponding to low-carbon ash of similar chemistry. Two factorial experiments show the effects of temperature, particle size, chemical content, and compressibility on the resistivities of four fly ashes of widely different chemical composition in the temperature range proposed for coal-fired turbines. Resistivities of all low-carbon ashes tested fall in the range 106 to 107 ohm cm at 1,500° F and should be removable by electrostatic precipitators. Ashes containing carbon in excess of about 8 percent, however, have low resistivity (as determined in nitrogen), especially at high temperatures. Therefore, high-carbon materials may not be collectable in precipitators because the resistivity is below the minimum value necessary for precipitation. Consequently, high carbon residues from partial combustion of coal probably could not be removed effectively at high temperatures.

Jan 1, 1968

By Christopher C. Jobes, Alan G. Mayton, Farid Amirouche

Based on prior mine vehicle studies of operators’ exposure to whole-body vibration, researchers from the National Institute for Occupational Safety and Health (NIOSH) evaluated four seat designs on mine haulage vehicles, with regard to roadway-induced jarring/jolting and operator comfort. Investigators collected objective and subjective data from vehicle operators on two existing and two NIOSH seat designs. This study included time and frequency response data using accelerometers and a data recorder, operator perceptions of jarring/jolting and discomfort levels using a linear visual analogue scale, and data from a questionnaire developed for this study. Results from the analysis of subjective data show that operators generally favoured the NIOSH-designed seats over the existing seats. The results of analyses from the absorbed power method and the threshold limit method, based on ISO 2631-1 (ISO, 1985), support the premise that NIOSH seat designs are superior to the existing vehicle seat designs on both models of mine shuttle cars used in the study. The NIOSH seat designs, featuring viscoelastic foam padding, were more effective in reducing vibration energy for operators exposed to vehicle jarring/jolting. In this paper, the performances of the NIOSH and existing seat designs are compared relative to the operator’s exposure to vehicle vibration (mainly jarring/jolting).

By Bill M. Stewart

The Bureau of Mines conducted laboratory tests to determine the effects on the physical properties of coarse coal waste of adding large amounts of fine coal waste. Maximum laboratory dry density, optimum moisture content, shear strength, and permeability tests were conducted on samples that contained 18 to 60 pct minus No.4 (U.S. Standard sieve size) coal waste. For the nonslaky materials, maximum laboratory densities were highest and permeabilities lowest when the samples contained between 30 and 40 pct minus No.4. Shear strength increased rapidly when the proportion of minus No. 4 was increased from 20 to 40 pct, but then increased only slightly or leveled off when the minus No. 4 was increased to 60 pct. Optimum moisture content and permeability were the physical properties most affected by the addition of fines. Optimum moisture content increased as much as 3 pct, and permeabilities decreased up to three orders of magnitude. Slaky coal waste material had physical property reactions to the addition of fines substantially different from those of nonslaky material.

Jan 1, 1981

By B. M. Bench

This Bureau of Mines report describes photo lineaments obtained from stereoscopic examination of vertical aerial photographs and by the Ronchi grating study of aerial photoindex sheets. The photolineaments are compared with the trends of oriented fracture systems procured by measuring the compass direction of joints in bedrock. The relative reliability of the methods is shown, and the results are presented in graphical, tabular, and written form. Analyses of field measurements of strikes of bedrock joints in the project area indicate for the most part two intersecting sets of major joints oriented N 76° W -N 15° E, and N 57° W -N 27° E. The analyses of lineaments determined by stereoscopic examination of aerial photographs show dominant trends of lineament zones of weakness to be an average of N 65° W -N 20° E. Analysis of lineaments found by Ronchi grid viewing of aerial photoindex sheets indicate dominant trends of N 70° W -N 27° E. The three methods give similar findings and verify the work of previous authors. The Ronchi grid method is a useful guide, but it cannot be substituted for the two more painstaking methods.

Jan 1, 1977

By Ray J. Holmquist

"INTRODUCTION The Copper King or Red River copper mine was examined on December 13, 1942, by the Bureau of Mines at the request of Richard Kelly of Santa Fe, N. Mex. The examination was made to determine whether the expenditure of funds for rehabilitation work necessary to make the workings accessible for examination would be warranted.As a favorable report was made, the workings of the Copper King mine were opened and sampled under the direction of the author. The portal of the Copper King adit was opened first. Considerable rehabilitation was necessary in the first 50 feet of the workings, but the remainder of the drifts and crosscuts were sufficiently open to permit surveying and sampling.An attempt was made to open the Waterbury atilt, which was reported to be about 30 feet east of the Copper King portal, and to crosscut the ore body nearly to its southern border. However, slide rock and mine dumps had completely obscured the portal of this adit, and no opening into it could be found or made.Work on the project was started on September 27 and vas completed on November 6, 1943."

Apr 1, 1947

By Oliver Bowles

The term "stone" in its broader sense includes not only the well-known limestone, marble, granite, sandstone, and slate but also precious and semi precious stones and many minerals and rocks not included in the principal groups. Stones have long been used for structural and ornamental purposes. To be so used, they must be cut to various shapes and sizes, and some must be polished to bring out their inherent attractiveness.

Jan 1, 1958

By Paul Sands

Single- and two-stage tests were made with 6-inch, coal-cleaning hydrocyclones to determine the effect of hydrocyclone geometry, operating conditions, and feed composition on performance. Most of the testing was conducted in an open-circuit pilot plant that had a maximum capacity of about 9 tons per hour. The coals used in the investigation had top sizes of 1/4 inch and 28 mesh. Considerable latitude was found in the range of geometry variables that could be used without affecting performance adversely, although a certain minimum ratio of overflow to underflow openings had to be maintained for best operation. Two-stage cleaning proved distinctly better than operation with a single hydrocyclone, because clean coal lost in the refuse product of the primary unit can be partly recovered in the secondary. There is an unusually great difference in the specific gravities at which the individual sizes of the feed are separated in the hydrocyclone. This militates against high efficiency because maximum yield occurs when all sizes are cleaned at the same specific gravity. The size composition of the feed and, more particularly, the size composition of the impurity have a greater influence on the efficiency attainable in the hydrocyclone than in most other types of fine-coal cleaners.

Jan 1, 1968

By A. G. Starliper

Research was conducted by the Bureau of Mines to determine feasible roasting methods for the removal and the recovery of germanium, cadmium, and lead as enriched fractions from sphalerite concentrates. The two types of roasting processes studied were: (1) Batch, with a stationary bed, and (2) continuous, with a suspended bed, Results indicated that either method gave satisfactory metallurgical recoveries} but the continuous process is recommended because of inherent advantages. Final products were enriched fractions that could be treated by conventional methods for production of metallic germanium, cadmium, and lead. In the batch process, the concentrates were placed in a large tube furnace and heated at 1,080° C, an average of 3 hours. During the heating period, inert, reducing} or sulfur-laden gases were passed over the stationary charge to convey the sublimed metal sulfides from the hot portion of the tube to a lower temperature condensing zone at the end of the tube, where the metal sulfides were collected on baffles and recovered. In the batch and fluidizing roasting processes alike, the gases passed over or through the charge and served only as carriers for the sublimates and as suspension media in fluidization roasting. Since both processes depended on the volatilization, at relatively high vapor pressures, of the sulfides of germanium, cadmium, and lead, it was imperative that very little oxygen come in contact with the charge to alter the sulfide minerals. Germanium has a high affinity for oxygen, but in this instance it was buffered by being in solid solution in zinc sulfide.

Jan 1, 1961

By R. Ward Stahl

Fire has been one of man's most useful tools through the ages and certainly is a "must" for industrial progress but when uncontrolled is one of the most destructive agencies. This fact is even more important in a coal mine, where many persons and much expensive equipment are confined in a relatively small area. Means of escape from a burning area, as well as from the products of combustion, are often limited; and in many instances the entire surroundings are combustible. Numerous mine fires, which resulted in a high death toll and great financial loss through the years, have caused mine owners to search for the best fire-fighting equipment; much of this has been installed, the quantity depending largely upon the experience of the individual companies or neighboring mines in certain coalfields. A mine owner or operator has meager published information on the actual fire protection afforded and systems of fire-fighting inaugurated in the coalfields, by which he could compare his efforts and get some idea of the adequacy of his own protection. To further general knowledge of the subject, it was decided to survey a representative number of mines in the field and show what has been accomplished. Representative mines were selected in various coal beds; some had similar tonnage, so comparison could be made if desired.

Jan 1, 1957

By W. P. Yant

The hazard to health from contamination of air by a noxious gas depends not only on the potential harmful response attending exposure., but also on the warning properties, which in effect may be termed the "accompanying warning response," This warning may be manifested as an odor, taste, irritation of the eyes, nose, or throat, or perhaps headache, vertigo,, or nausea. These manifestations may be painful and even slightly harmful, but to a much lesser degree than the primary injury of exposure. The warning response mitigates hazards directly in proportion to the degree of intolerability which -accompanies injurious exposure, and accordingly its absence augments hazards. This accounts for the fact that the actual health hazards from a nonodorous or non-irritating gas or vapor of comparatively low toxicity sometimes equal or exceed the hazard from a considerably more toxic substance, but one which possesses a marked odor or produces eye, nose, or throat irritation in advance of harmful exposure. When a substance lacks the properties for giving warning, it is often possible to impart them by the addition of a small amount of another substance which has an exceedingly high warning intensity. The vapors of this substance, commonly termed a "warning agent" or "tracer gas," escape and mingle with the gas or vapor which lacks warning properties and thereby apprises persons of the latter's presence. The amount of the warning agent added is that which will give adequate warning in advance of serious physiological harm from the dangerous gas or vapor.

Jan 1, 1930

By A. J. Farstad, R. F. Kehrman

Characteristics of metal/non metal mines were evaluated to determine the suitability of applying the U.S. Bureau of Mines electromagnetic location system to the problem of locating trapped driers in metal/non metal mines. Statistical distributions of mine depths and overburden conductivities show that the existing USBM EM system is inadequate for most metal/non metal mines. Alternate approaches to trapped miner location in deep mines were identified and subsequent field tests were conducted at six (6) mines to evaluate their feasibility. The approach considered to be the most promising is one which utilizes the existing manpack transmitting system, modified slightly for a dual frequency output, in conjunction with a sophisticated signal processing receiver on the surface. The main advantage of staying with a "through the earth" approach is that the underground equipment can be kept simple, easily maintained, light- weight and inexpensive.

Jan 1, 1979

By Samuel P. Harteis, Eric S. Weiss

The National Mining Association and the Mine Safety and Health Administration requested that the National Institute for Occupational Safety and Health (NIOSH) conduct full-scale evaluations of a recently developed carbon fiber-reinforced polymer (CFRP) reinforcement technique for upgrading existing mine ventilation seals to withstand an explosion pressure of 50 psi or greater. The evaluation was conducted in the NIOSH Pittsburgh Research Laboratory’s Lake Lynn Experimental Mine (LLEM) near Fairchance, PA. The purpose of the evaluation was to determine the blast resistance of the CFRP reinforcement technique, designed to increase the strength of two types of existing 20-psi-rated in situ mine ventilation seals. Two candidate ventilation seals were selected to represent the 20-psi alternative seal designs typical of those used in mines prior to July 2006. Installed within the LLEM were (1) a 4-ft-thick pumpable cementitious foam seal using material with a designed 150- to 200-psi average compressive strength at 28 days and (2) a 24-in-thick, low-density cementitious block seal with a center pilaster and keyed to the floor and ribs. The materials necessary for the CFRP reinforcement technique were then installed on the outby (active) side of each seal, and the seals were subjected to explosion overpressures. Both seals with the CFRP reinforcement retrofit successfully withstood explosion pressures of 60 psi or greater during the full-scale evaluations in the LLEM.

Jan 1, 2008

By J. J. Demeter

A tube-wall reactor with a Raney nickel catalyst deposited on the outer wall of the tube by flame spraying is effective in the practically complete conversion of 3H2+1CO synthesis gas to a high-Btu gas (methane) at an hourly space velocity of 7,000 volumes of gas (NTP) per hour per volume of annular volume. Partially reacted synthesis gas containing an appreciable amount of methane can also be treated in this reactor to increase the heating value to over 900 Btu per cubic foot. Excellent heat removal through the metal wall to a coolant and temperature control were obtained. The heat transfer co-efficient from the catalyst to the coolant was about 275 Btu per hour per square foot per ° F. Synthesis tests were conducted with tubes 1.2 inches in ad by 6 inches long, and 1.3 inches in od by 36 inches long. When operating at a synthesis gas rate of 100 to 120 scfh per square foot of catalyst-coated tube, catalyst life was long enough to realize a catalyst cost for the raw Raney nickel alloy of about 0.3 cent per 1,000 cubic feet of pipeline gas (900 to 950 Btu per scf). Gas recycling at ratios of 1:1 to 3:1 was effective in increasing conversion and in extending the life of the catalyst to about 16 weeks. In cost and in operating characteristics the tube-wall reactor compares favorably with the fluidized-bed and hot-gas-recycle reactor systems for the synthesis of high-Btu gas from H2+CO.

Jan 1, 1967

By S. J. Hussey

A jig tailing with gold content ranging from 0.33 to 0.43 oz/ton was leached in weak cyanide solution with extractions of up to 97 pct in 24 hours. By countercurrent batch leaching studies and laboratory pilot plant operation, minus 10- plus 20-mesh and minus 6- plus 16-mesh coconut carbon were loaded to 700 oz/ton of Au. Minor silver in the ore reported in the carbon in amounts of up to 100 oz/ton. Gold adsorption rate data and an equilibrium adsorption curve for minus 10- plus 20-mesh carbon at ambient temperatures were developed and used in the successful application of a cascade design theory. The work was performed as a part of the overall Bureau of Mines research effort to help maintain an adequate domestic supply of metals by making improvements in mineral-processing technology.

Jan 1, 1979

By G. M. Molinda, J. P. Ulery

Since 1970, abnormally high methane emissions have been observed in eastern sections of the Federal No. 2 Mine operating in the Pittsburgh Coalbed in northern West Virginia. The nature and volume of these emissions indicate a source other than the coalbed. An investigation was undertaken to delineate probable methane sources. Gas well information and stratigraphic correlation of corehole data indicates that a sandstone directly above the main coalbed is an additional source of methane emissions. The sandstone body appears to be an ancient stream channel, infilled with fine-grained sand and organic matter. Coalification of the organic matter produced methane as a byproduct. Additional methane presumably migrated into the sandstone unit from the subjacent coalbeds. The methane became trapped in the porous clasticunit by the surrounding impermeable strata. Mine development near this unit creates a significant pressure gradient, triggering abnormal methane emissions into the mine along naturally occurring fractures. Pre-development methane drainage of the sandstone could be accomplished by completing vertical boreholes along its trend.

Jan 1, 1984

By P. W. Jeran, C. D. Sullivan, C. M. McCulloch

A series of geological surveys were completed in six coal mines in connection with a Bureau of Mines research program on methane control. The aim of these surveys was twofold: First, to study the overall geology of the coalbed, and second to use the resulting data to evaluate the influence of the geological characteristics of the coalbed on safe and efficient coal extraction. This report explains the advantages of geologic maps and fence diagrams in coal mining, and how the knowledge gained from such geologic investigations of mines can help control many underground problems.

Jan 1, 1975

By J. Weinberg

This Bureau of Mines report presents data on the changes in the use of steel in motor vehicles over the past 35 yr. Sources of supply of steel for the automotive sector have shifted from almost all domestic in the 1950's to about 50% domestic and 50% foreign in the 1980's. Downsizing, design changes, and substitution of lighter weight materials to achieve energy efficiency also contributed to the market loss of the domestic steel industry. Although plastics and aluminum have displaced some steel in motor vehicles over the years, heavy low-carbon steel is now being replaced most rapidly by lightweight high-strength steel. If the percent of domestic steel used in motor vehicles had not declined since 1950, domestic industry would have supplied 9.3 million more short tons of steel than it supplied in 1985. Downsizing and design changes accounted for 43% of the loss; steel imports, 32%; and substitution of plastics and aluminum, 25%. In 1985, the total value of market share lost by U.S. steel producers was $5.1 billion, of which $1.6 billion was lost to foreign steel producers and automobile manufacturers. Through aggressive marketing and increased efficiency, however, the domestic steel industry may be able to recapture some lost markets, as applications for high-strength steels expand, and as foreign-owned automotive plants in the United States provide fresh sales opportunities.

Jan 1, 1988