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By W. D. Mcmillan

Soapstone is the term applied to an impure, massive, soft rock with a greasy feel. It is of variable composition, consisting chiefly, however, of talc, tremolite, and chlorite. Although limited quantities of soapstone are used as building material, in fireplaces, and in the manufacture of laundry tubs, sinks, laboratory-table tops, and-oven and furnace blocks, the principal part of the production is ground for use in roofing paper, insecticides, and as a filler in asphaltic paints.

Jan 1, 1949

By R. R. Backer

The Bureau of Mines investigated the typical physical and chemical properties of coal waste materials from the western part of the United States. The results are compared, in so far as possible, with the properties of waste materials from eastern coal operations. The authors found a disparity of mines and preparation plants among western U.S. coal operations and dissimilarities with typical operations in the East. The relatively cleaner product from the predominance of surface mining and the occurrence of thicker seams in the West reduces the amount of coal preparation required and the size of the waste piles. Because of the abundance of land available for waste disposal, many of the piles are low and extended over large areas. New concepts relating statistical shear strength data to liquifaction potential are presented. The somewhat limited data indicates that western coal sludge is coarser with higher permeabilities and shear strengths than the eastern deposits.

Jan 1, 1977

By R. E. Lindstrom

Effective separation of rare-earth mixtures is obtained using hydrogen as a retaining ion at 200° F with ethylenediaminetetraacetic acid (EDTA) eluant. Results obtained in Bureau of Mines bench-scale apparatus and large columns with hydrogen as a retaining ion closely parallel those obtained with copper as a retaining ion. The use of hydrogen as a retaining ion permits EDTA and water, collected before rare-earth breakthrough, to be recovered in a form that allows the material to be recycled without extensive processing. With the exception of yttrium and dysprosium, separation of rare-earth mixtures is improved and throughput is increased by elevated temperatures. Separation with 1,2-diaminocyclohexanetetraacetic acid (DCTA) eluant increases markedly on increasing temperature from ambient to 250° F; however, on the basis of separation efficiency, DCTA does not compare favorably with EDTA.

Jan 1, 1962

By A. W. Fahrenwald

The art of flotation has developed rapidly. Numerous technical staffs and individual investigators have, by their combined efforts, developed practicable methods of concentrating ores which ten or even five years ago were considered complex and impossible of commercial treatment. Also the work of those who have been engaged in pure research on the fundamentals of flotation has helped greatly to expedite the general development of the process. However, in spite of the highly successful practical operation of the flotation process, results are obtained and things happen that we are unable to explain completely, although much is known about the theory of the process. The rapid stride in flotation concentration, it is noteworthy to point out, is due to the freer exchange of facts and data by the staffs of the larger mining companies and the patent controlling corporations, and by investigators in general. Generally speaking, one may visit any mining plant and by presentation of proper credentials, be shown all that is going on or that is being done.

Jan 1, 1925

By William H. Pomroy, Annie M. Carigiet

This U.S. Bureau of Mines publication is an analysis of underground coal mine fire incidents occurring in the United States during the 15years from 1978 through 1992. The fire data used in this analysis were obtained from U.S. Mine Safety and Health Administration mine fire investigation reports. Fires were analyzed by year, State, coalbed thickness, mine size, mining method, ignition source, burning substance, location, equipment involved, detection method, time of day, time of year, number of injuries and fatalities, method of extinguishment, and evacuation measures taken. In all, 164 fires are included in this report, or an average of 10.8 fires per year. The most fires occurred in West Virginia, Kentucky, and Pennsylvania, respectively. However, the fire incidence rates for these States, expressed as the number of fires per million tons of coal mined, were the lowest, second lowest, and fourth lowest of all underground coal producing States. The most common ignition source was electricity; the most common burning substance was coal; the most frequent fire location was the belt entry; the most common equipment involved in fires was the conveyor belt; and the most common extinguishing agent was water.

Jan 1, 1995

By Russell. Paul L.

"INTRODUCTION Preliminary reports by Bureau of Mines engineers 3/ and by the Federal Geological Survey 4/ suggested that exploration would discover substantial reserves of minable ore in the Contact mine, Grant County, New Mexico. During February and March 1943, a sampling program was conducted on this property under the direction of the author. This was art of a general survey of the manganese districts of southwestern New Mexico.In its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources, to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as practicable soon as after its conclusion. The Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocer, chief, analyzes samples and performs beneficiation tests. Both these branches are under the supervision of Dr. S. Dean, assistant director. With respect to this report, special acknowledgment is due to C. H. Johnson, district engineer for New Mexico, and E. D. Gardner, regional engineer, and his staff, of the Central Region of the Bureau of Mines at the time of this work in 1943; also to Kenworthy, metallurgist at the Rolla. Mo., Laboratory of the Bureau of Mines, for work on beneficietion of the ore, and Sherman K. Neuschel, geologist of the Federal Geological Survey, for assistance in interpreting geological data at the project."

Oct 1, 1946

By Kathleen Madland Kowalski

In recent years the issue of human stress response in emergency workers has begun to receive attention. This paper presents a rationale for considering human stress as a significant factor in the management of emergencies. It discusses the concept of stress, Critical Incident Stress in emergency responders, and introduces the Critical Incident Stress Debriefing (CISD) process. It is suggested that, in a disaster, the CISD process can improve the effectiveness of response teams on site, their turnaround time on site, and post disaster time off the job. This paper, prepared by a US Bureau of Mines research psychologist, offers some ideas to the mining industry in general, mine rescue trainers, and more universally, to those responsible for developing emergency management plans.

By Kenneth B. Higbie

Expenditures to advance scientific technology in general reached an all time high in 1965 with some $22.2 billion estimated to have been allocated by government and industry. Federal Government expenditures were estimated at $15.4 billion, with almost 90 percent of the funds devoted to programs involving defense, atomic energy, and outer space efforts. With this massive effort in the United States and a very impressive effort elsewhere in the world, there is little wonder that many new metallurgical developments were announced in the technical press during the year. No effort has been made to cover all aspects of the industry, but a few of the developments are described in this chapter.

Jan 1, 1966

By Potter G. M.

Ore-dressing tests were conducted on a sample of ore submitted by the Richmond Hill Mining Co. of Lead, S. Dak. as a part of the Bureau of Mines program for investigating potential domestic sources of manganese. Half of the sample was taken from the 300-foot level and half from surface cuts. The problems involved were liberation and rejection of silica and iron and removal of lead, Silver, and gold from the manganese concentrates. Although a portion of the silica and iron oxides was too intimately associated with manganese minerals for rejection by ore-dressing methods, thus limiting recovery of high-grade concentrates, the Richmond Hill ore was found amenable to simple gravity methods of concentration for producing intermediate-grade products. By jigging and tabling, 73.8 percent of the total manganese was recovered in a product that, when sintered, assayed plus 40 percent Mn. Lead, silver, and gold were successfully removed from gravity concentrates by a chloridizing roasting treatment.

Jan 1, 1948

By Walter T. Ackley

[The geophone has occupied a prominent position as a mine signalling device since its first introduction. The Bureau has carried out tests at different times with a view to improving the early geophones. The following paper describes briefly the adaption of the vacuum-tube audio frequency Amplifier to a new form of geophone. It is not intended to convey the idea that the results described are sufficient to warrant the drawing of definite conclusions as to the practicability of the electrical geophone, but the data and tests liven herein are made public because of their possible use to the industry and as a result of inquiries received as to the feasibility of such adaptions and modifications of the early geophones. Because of the limited time available to the authors, only one geophone with its auxiliary amplifier was constructed. As is well known, two geophones are necessary in order to determine the direction of a sound. Although the principles upon which the electrical geophone operates appear to be fundamentally correct, it is not possible to state whether two such devices 'rill function as efficiently, (as regards determining direction of sound) as the present geophone. In order to operate efficiently as a direction finder, the amplifiers of the electrical geophone must each amplify with exactly the same degree of magnitude. By proper design and adjustment this can probably be accomplished without greatly complicating the design. inasmuch as audio frequency amplification is used, no tuning; is necessary as is the case with tuned radio-frequency circuits. The same filament and plate batteries can be used to operate the amplifiers and by the use of dry cell tubes, requiring shall filament and plate currents, it if believed that a compact, portable and practical instrument can be evolved. Further investigations of the electrical geophone should be conducted to determine the points outlined in this preliminary report.]

Jan 1, 1924

By Manuel Gomez

A computerized, interpolative mapping technique based on the moving average method was shown to be adequate to estimate the between-drill-hole values of coal-seam variables. The forecasting of the spatial distribution of coal properties along the seam was of three kinds: (1) Estimation of the variable of interest on a regional basis from widely spaced sample points, (2) prediction of coal properties for product control from closely spaced data, and (3) prediction of coal properties for specified benches, or layers of the coal seam, from closely spaced sample points. Estimates obtained with the computerized, interpolative mapping procedure were useful in the delineation of seam thickness, elevation, and overburden and in the estimation of sulfur and ash concentrations during the early phases of exploration. This grid interpolation technique was found adequate to adjust between-drill-hole values for trends resulting from the combined effect of several variables on a measured response. This information, coupled with statistical and geologic data that can be obtained in the exploration phase of mining, enlarges the information base available for coal-mine development planning, energy forecasts, and environmental control associated with fossil fuel power generation.

Jan 1, 1972

By S. H. Katz

"At the annual meeting of the International Association of Fire Engineers at Kansas City, Mo., in June, 1919, the Bureau of Mines offered to cooperate with municipal fire departments for the purpose of obtaining information regarding composition of the air in burning buildings. (Katz, S. H., Statement made at Convention of International Assoc. of Fire Engineers: Fire and Water Eng., vol. 66, July 16, 1919, pp. 129-30, also Fireman's Herald, vol. 78, July 12, 1919, pp. 48.) The gas-mask laboratory of the Bureau's experiment station at Pittsburgh sent vacuum bottles for taking samples to fire chiefs in twenty-five cities, who had signified their intention to aid in this work. It was hoped to obtain one hundred or more samples, because statistics in quantity are necessary for drawing reliable conclusions concern-in the likelihoods of encountering irrespirable as in burning buildings. This far, eleven samples have been received by the laboratory. Results of analyses and pertinent data regarding these samples are given in the accompanyingEight of the eleven samples contained, no carbon monoxide; seven of the eight were taken above the ground level and one below ground. One sample taken above ground contained 0.03 per cent carbon monoxide, and this quantity is not dangerous to breathe for a limited time. Of the three samples taken below ground, one contained no carbon monoxide; the other two contained 0.10 and, 0.35 per cent, respectively. This indicates that in a burning building, the hazard from carbon monoxide is much greater below the ground level. The cause undoubtedly lies in the poorer ventilation that is usually found in cellars or basements. Abundance of ventilation provides the necessary air for complete combustion, or if incomplete combustion does occur, the carbon monoxide generated by the fire is greatly diluted with fresh air and swept away by the current. It may be noted that the highest proportion of carbon monoxide was found in a cellar where a fire as burning among piled cases. The difficult access of air to the burning parts facilitated the formation and lib ration of carbon monoxide. The smoke here was very light and no difficulty was experienced in breathing. Some of the air containing dense smoke showed little change from normal air by analysis. Thus the density of smoke or the irritation and difficulty it causes in breathing are no indication of the presence of poisonous gas. None of the samples shows important oxygen."

Nov 1, 1920

By N. N. Moebs

The atmosphere in part of an air-sealed coal mine was monitored continuously through a drill hole for oxygen content to determine the effectiveness of sealing a mine against the entrance of air and the major force that caused the phenomenon of mine breathing through the overburden. The differential pressure across the seal and the barometric pressure on the outside also were recorded. A general correlation, obtained between the oxygen level, differential pressure, and barometric pressure, indicates that changes in air pressure are the cause for periodic replenishment of the oxygen in the mine. Mine effluent quality was determined by conditions in many sections of the mine and could not be related to the oxygen level at the drill hole.

Jan 1, 1972

By Nicholas Kyriazi, John P. Shubilla

A joint effort by the U.S. Bureau of Mines (USBM) and the US. Mine Safety and Health Administration (MSHA) was undertaken to determine how well self-contained self-rescuers (SCSR's), deployed in accordance with Federal regulations (30 CFR 75.1714), held up in the underground environment with regard to both physical damage and aging. This report presents findings regarding laboratory-tested SCSR's in the fourth phase of testing from 1989 to 1993. The SCSRYs were tested on human subjects and on a breathing and metabolic simulator (BMS). These results indicate that most of the apparatus, if they pass their inspection criteria, perform as expected except units with manufacturing defects. However, when the apparatus are carried in and out of the mine daily and stored at the working section, they may suffer abuse. Physical signs of abuse, unless extremely obvious, are frequently not detected by the miners or mine operators. In addition, some apparatus collected for this study had not been returned to the manufacturer in a recall effort for correction of a manufacturing defect. In both cases, the apparatus would have presented problems in emergency use. Recommendations include improved training in inspection procedures and better enforcement of recall notices.

Jan 1, 1994

By H. M. Smith

In studying the chemistry of lubricating-oil fractions from so-called ?paraffin-base? crudes, one of the first requisites is a method for the separation and removal of waxy material. A method utilizing solvents for this purpose is described in this report, together with preliminary experiments with solvents that led to its development. The solvents actually used are secondary butyl alcohol, acetone, and mixtures of these.. Isopropyl alcohol was also studied. Preliminary Experiments In previous work on "intermediate-base" crude oil, following the work of Wyant and Marsh acetone had been used for laboratory separations of oil and wax. Then acetone was tried for the separation of the waxes and oils of "paraffin-base" crude, the volume of acetone required (80 parts to 1 part of oil) was found to be too great for large-scale work. For this reason the effectiveness of other solvents was studied; the separation by acetone, however, was used as a standard.

Jan 1, 1927

By Suresh K. Bhatt

A mathematically simulated modeling technique is used in this U.S. Bureau of Mines report to represent a hypothetical mining operation with existing mining technology and prevalent mining costs. Mining scenarios were prepared and evaluated for potential benefits and costs available through computer-assisted mining. Base criteria, parameters, and methodology are described.

Jan 1, 1991

By H .. B. HUMPHREY, F. E. Cash

Sixty-one fatal accidents were reported in the mines of Alabama during 1930. This number is a decrease of 15 per cent as compared with 1929; however, production was 13 per cent and the man-hours worked were 16 per cent less than in the previous year. There were 21,731 men employed inside and 3,386 outside. Table 1 gives the comparative rates per million tons and per million man-hours for the United States and for Alabama for 1929 and 1930. These rates are based on figures published by the State and by the United States Bureau of Mines, with preliminary figures for 1930. (These sources of data are used throughout this paper.)

Oct 1, 1931

By G. R. Palmer

Using a fluidized, countercurrent multiple-compartment ion-exchange (MCIX) column previously developed by the Bureau of Mines, Bureau researchers have successfully extracted uranium from a simulated acidic in situ leach liquor that contained 150 ppm U30s? This successful demonstration of the MCIX system is reported, and the effects of varying the operating conditions on the performance of the system are also examined. Operating the MCIX system with a flow rate of 15 gpm/ft2 and an aqueous-to-resin flow ratio of 200:1, more than 90 percent of the uranium Has extracted, and a resin containing approximately 28 grams U308 per liter was produced. The absorption column used to investigate the operating variables was approximately 18 feet long with a 2-inch ID and was divided into compartments that were 1 foot long.

Jan 1, 1980

By J. H. Schuenemeyer

Consider a set of points, some of which are anomalous (larger than a specified cutoff value), located on a plane. Whether some or all of these points are clustered to form one anomaly or more or, alternatively whether these points are scattered at random, may be investigated by measuring perimeters of convex hulls. A convex hull is the smallest convex polygon that will encompass a group of points. (Examples of convex polygons are triangles, rectangles, and all other regular polygons.) A set of anomalous points is selected and the perimeters of the convex hulls of this set and all its subsets are measured and compared with tabulated values of perimeters for each subset size. For a given subset size consider those perimeters which are less than the tabulated perimeter. If the number of convex hulls is greater than the maximum number expected by chance, then the chance that any one of the observed-hulls-is a nonrandom cluster is the ratio of the observed number to the sum of the observed and the maximum number expected by chance. Otherwise, the points are evidently not clustered. If many sample points are anomalous, an alternate model defines various configurations of contiguous points and compares the observed number of configurations per unit area with the expected number. Applications are discussed in several fields of geology and geochemistry-including geochemical exploration surveys and heavy mineral spatial distributions--as well as in mining (dust control) and medical geography.

Jan 1, 1972

By Bertrand L. Johnson

Langbeinite, a comparatively rare mineral that has been reported from only five countries in the entire world, has recently attained considerable economic importance in the United States and Poland. Since September 1940, several hundred thousand tons have been produced in one of the Carlsbad (N. Mex.), potash mines for chemical and fertilizer use. As it is a newcomer in this field, and as it is the source of fertilizers possessing special advantages, notably for soils deficient in magnesium or requiring sulfate fertilizers, a discussion of its properties, occurrences, uses, mining, and treatment is appropriate at this

Jan 1, 1944