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By John C. Edwards, Gene F. Friel

A series of liquid fuel fire experiments evaluated the comparative responses of five types of commercially available smoke detectors and a diffusion-mode carbon monoxide (CO) detector under normal and reduced airflow conditions based upon the alarm times of the detectors. These experiments were conducted in the Safety Research Coal Mine at the U.S. Bureau of Mines Pittsburgh Research Center. Two of the smoke detectors had manufacturer set alarms. For the other three smoke detectors, an alarm point was defined in terms of their background analog signal and the detector's electrical output noise under ambient conditions. A correlation was developed of the travel time of 5 ppm CO between pairs of CO detectors with the travel time calculated from entry and crosscut volumes and measured airflow. Based upon the relative performance of smoke detectors in this limited study, smoke detectors can be as effective as CO detectors for mine fire detection once identifiable alarm values are defined. Implementation of smoke detectors as part of an atmospheric mine monitoring system will improve mine safety.

Jan 1, 1996

By Earl F. Hastings

The Pilgrim mine, operated by the Pioneer Gold Mining Co., is 9-1/2 miles west of Chloride in the Pilgrim mining district on the eastern slope of the Black Mountains, or River Range, Mohave County, Ariz. In March 1937, 100 tons of gold ore per day were being mined and milled at the property by a total force of 5i men. Climatic conditions allow year-round operations. Due to present activity in the county there is an ample supply of labor for the requirements of the mine. The Pilgrim is the only producing property within s radius of 6 miles; recently, however, the South Pilgrim Mining Co. has launched a development campaign on claims that adjoin the Pioneer Co. property to the south.

Jan 1, 1937

By Oliver Bowles

The United States Bureau of Mines has within its ranks a group of engi- neers who are engaged in working out quarry problems, the solution of which will be of general benefit to the industries involved. The problems undertaken are approached in a systematic and thorough manner, all the evidence for and against any proposed change or new development being collected as carefully as an attor- ney would prepare his data on an important case. Unlike the attorney, however, the Bureau engineer does not take sides; his judgment is based entirely and in- partially on the array of facts presented. In order to gain the desired infor- mation he visits many plants, consults with the leaders in the industry, works out experiments in his laboratory, and supplements this information with a stu- dy of all available literature already published on the subject in any part of the world. As an engineer who has for eight years conducted such inquiries in the stone industry, I propose to discuss the Bureau of Mines viewpoint; and it may be of interest to consider with me in a brief and general way the engineer's method of looking at quarry problems, and some of the results attained through past and present labors. While the Bureau has conducted no investigation directly for the crushed- st one industries, two years of investigative work at cement-plant quarries, and work now being conducted at lire-plant quarries, has a very direct bearing on the problems of the crushed-stone industry, since stripping, drilling, blasting, loading, and transportation are similar in many respects in all stone quarries. The results of cement-plant quarry investigations are to be found in Bureau of Mines Bulletin #160. (b) Two short papers on lime-plant quarry problems have been issued in mimeographed form as Serial #01 (c) and Serial 3 (d).

Jan 1, 1923

By D. S. Kingery, F. F. Kopsch

The practice of using two or more main ventilating fans is common at large coal mines throughout the coal-mining industry. To assure adequate and efficient ventilation at may mines, such multiple-fan systems are necessary. The hazards associated with interrelated ventilating currents if a fan fails are controversial, and to date little effort has been made to study this specific problem and to determine corrective measures. The obvious questions are: 1. Is there a hazard? 2. Under what circumtances does it exist? 3. How serious is it? 4. What are corrective measures? Most members of the mining fraternity agree that reduced quantities of air and changed airflow patterns introduce potential hazards, especially where gaseous conditions exist when mechanized methods are used in concentrated mining 0 The seriousness of the hazard depends on the ease with which methane accumlates in face areas or haulage roads, the quantity of methane in workedout areas, and the extent to which reversed air currents interfere with escape and recovery operations after mine fires or explosions. These studies cover three mines and give the distribution of air for the specific conditions show. Each mine probably has somewhat different airflowpressure relationships between fans. This depends on the number of fans, the

Jun 1, 1959

By Philip C. Tully

This bibliography contains 3,062 different citations to technical and scientific literature about helium and alpha-particles abstracted by 13 abstract service publications during 1963. Multiple subject classification has increased the total number of entries to almost 5,000. Helium citations are listed by 23 major classifications. The number of subclassifications has been greatly increased to minimize the time required for literature search. The use of automatic data processing has been extended in compiling the bibliography.

Jan 1, 1970

By Kathleen M. Kowalski

In emergency management, the effects of stress on the performance of emergency personnel, typically have been ignored or regarded as too enigmatic to quantify. This paper discusses the concept of Critical Incident Stress in responders to emergencies. It presents the rationale for considering stress as a significant factor in the management of emergencies. It is proposed that Critical Incident Stress Debriefing in a disaster can improve the effectiveness of response teams on site, their turnaround time on site, and post-disaster time off the job. Critical Incident Stress intervention also can mitigate potential deleterious emotional effects associated with emergency work. This paper, prepared by a U.S. Bureau of Mines researcher, offers some ideas to the mining industry in general, to mine rescue team trainers, and to developers of program simulations on the specific issue of how people, time, materials and space may be factored into a plan for emergency management. The impact of stress on emergency workers is, presented as a missing component in present emergency management models.

By T. F. Mitchell, J. V. Batty, R. R. Wells, R. Havens

"INTRODUCTION )ne of the most important wartime activities of the Bureau of Mines was the search for new sources of minerals necessary to the prosecution of the war. As a part of the investigation of strategic mineral deposits in the United States under the Strategic Minerals Act (Public 117, 76th Cong., 1st Sess., Ch. 190), examining engineers of the Bureau of Mines investigated and sampled various deposits of chrome ore in California, Idaho, Montana, Oregon, and Washington, and those deposits that warranted further study were explored by diamond drilling, trenching, and drifting, as re¬quired. During these investigations, samples were submitted to the Ore Dressing Section of the Salt Lake City Station for metallurgical testing. This paper gives data summarizing results obtained from laboratory ore-dressing studies of the chrome ores submitted.Although the deposits range widely in geographical location, the mineral occurrence of all of them is strikingly similar. Chromium, in all of the ores tested, is present as impure chromite or chromium spinel. Although pure chromite (FeCr204 or FeO.Cr203) contains 68 percent chromic oxide, the iron may be replaced in varying amounts of magnesium, and the chromium may be replaced similarly by aluminum and ferric iron. In studying concentration methods as applied to chrome ores, the composition of the chrome mineral is of fundamental importance, because it is manifestly impossible to produce a high-chrome concentrate from a low-chrome chromite by any mechanical process.In all but one of the ores, the gangue material consists of olivine or altered olivine minerals such as serpentine, antigorite, and chrysotile. The exception, the Antelope or from Montana, has a gangue chiefly composed of actinolite, chlorite, and talc."

Jun 1, 1947

By James J. Dowd

During and immediately following World War II, the heavy demands for steel required the mining of unusually large quantities of coal for the manufacture of metallurgical coke. The largest demand for metallurgical coke is in the Appalachian region, which comprises central and western Pennsylvania, Maryland, West Virginia, Virginia, eastern Kentucky, Tennessee, and Alabama. This demand is satisfied by coke made from coals within the region; consequently, the reserves of coking coal in this region are being depleted more rapidly than reserves in other coal-producing regions. The supply A' high-quality coking coal during the war was inadequate, and some coke were forced to use inferior coals. The coke produced from these inferior coals adversely affected the rate of production. Another national emergency probably would produce a similar condition, and in the interest of -national security, the Munitions Board of the National Military Establishment requested the Bureau of Mines to evaluate the reserves of coals suitable for the manufacture of metallurgical coke. All bituminous coals in the Appalachian region are coking, and as the coal that produces the better metallurgical coke become depleted, other coal previously considered inferior will be used. The general trend is toward the use of lower-quality coals for metallurgical purposes.

Jan 1, 1950

By C. W. Huggins

The primary objective of this Bureau of Mines research was to measure the size distribution of respirable quartz collected at metal mines, nonmetal mines, and processing plants to select the best reference standard for use in quantifying quartz in mine and plant dust samples. The secondary objective was to size all the nonquartz particles collected at the same sites. Particle size measurements were made on 29 samples using a scanning electron microscope in the backscatter mode of operation, interfaced with an image analysis system. The Mine Safety and Health Administration, Denver, CO, provided the 29 samples, which were collected at mines and processing plants in 19 states. The accumulated particle size measurements indicate that NBS 1878, minus 5-f.lm Hin-U-Sil, and minus 5-f.lm Supersil would be preferred over Silver Bond B as reference standards for most quantitative determinations by X-ray diffraction and infrared spectrometry. The respirable dust samples collected at sand plants, however, would be better served by a new reference standard having a quartz particle size distribution of approximately 2.2 um, as none of the four existing reference standards matched closely with them. Commercially available NBS 1878 and minus 5-um Hin-U-Sil CQuid be used as reference standards for 28 of the 29 samples studied in this investigation.

Jan 1, 1986

By Oliver C. Ralston

Nonmetallic technologic investigations of the U. S. Bureau of Mines are headquartered at experiment stations in three widely separated localities of the United States. During 1936, the Nonmetals Division of the Technologic Branch was formally set up by combining the direction off the work of these three experiment stations under one administration. The New Brunswick (N.J.) station which in the past has been known as the Nonmetallic Minerals Experiment Station, is henceforth to be at College Park, Md., as part of the Eastern Experiment Station, and its principal activities will be related to the nonmetallic resources of the Eastern and New England States.

Jan 1, 1937

Reduce exposure of longwall face workers to respirable dust generated during the advancement of roof supports. Approach Identify and implement current water-application and improved support-movement practices used to lower support-generated dust. Defining the Problem Bureau studies have shown that on some longwall faces support dust can contribute over 30 percent of the respirable dust exposure of face workers. Conditions contributing to high levels of respirable dust generation during support movement are: depth of cover greater than 1,000 ft; immediate roof consisting of coal top or friable shales; and face-air velocities in excess of 500 fpm. Moreover, at most longwalls, supports are advanced on the intake-air side of the shearer as it travels with the airflow. This places the shearer operators, and in many cases the support movers, downwind of support advance, thus increasing their respirable dust exposures.

Jan 1, 1984

By A. C. Smith

The U.S. Bureau of Mines conducted a study to evaluate the effect of ventilation on the water spray patterns of automatic sprinkler heads. Experiments were performed in a rectangular tunnel with pendent, upright, pendent sidewall, and horizontal sidewall sprinkler heads at air velocities of 0, 150, 300, 500, and 800 ft/min. As the air velocities were increased, there were significant shifts in the total coverage areas, density distribution patterns, and the maximum coverage densities for all types of heads. The pendent and upright heads exhibited upstream shifts in total coverage in the direction of the air-flow ranging from 4 to 6 ft, while the downstream coverage distances were extended up to 14 ft at the 800 ft/min airflow. The shift in upstream coverage distance for the sidewall heads ranged from 6 to 12 ft, while the downstream coverage was extended up to 22 ft at 800 ft/min. The results showed that airflow can have a significant effect on the coverage characteristics of automatic sprinkler heads and needs to be considered in the design of effective sprinkler fire suppression systems for ventilated areas.

Jan 1, 2010

By William L. Crentz

Late in the nineteenth century en active coal-mining industry was begun in the Lower Freeport bed near Reynoldsville, Pa., where the bed thickened to more than 10 feet in places . The coal was readily accepted as an excellent steam fuel. Much of the thick coal his been depleted, but there are many areas where the deposit averages about 14 feet in thickness. As the more desirable mining sites were worked out in the Lower Freeport bed, other beds were exposed from which will come the county's major cowl production in future. The Lower Freeport bed is still the most important bed in Jefferson County from a production standpoint. The Lower Kittanning bed is second. Sporadic mining is being done in the Upper Freeport, Upper Kittanning, Middle Kittanning, Clarion, and Brookville beds. Strip mining has permitted recovery of much coal that could not be mined profitably by conventional underground methods.

Jan 1, 1953

By R. L. Solmer

During 1959-61, the Bureau of Mines investigated the strain and deformation induced in rock and concrete linings around mine openings by retreat panel caving at the Climax Molybdenum mine. Two concrete-lined slusher drifts on the Phillipson level of the mine were instrumented with both electrical strain gages and extensometers. Changes in strain and deformation were recorded over an 18-month period during the undercutting and caving of the mining panel. General agreement was found between the strain and deformation measurements and the hypothesis that the vertical component of the stress field on the openings is almost completely removed by undercutting. This phenomenon is a possible explanation for the structural failures that occur in the slusher drifts during the undercutting cycle.

Jan 1, 1965

By R. L. Grant, R. W. Van Dolah, N. E. Hanna

An experimental investigation was conducted to assay the relation between natural gas concentration and ignitibility of the gallery atmosphere . Both the gas concentration representing maximum ignitibility and the relationship between certain properties of the explosives and their incendivity are discussed . The data show that variation in the natural gas content in the gallery can have a highly significant effect on ignitibility of the gallery atmosphere ; maximum ignitibility of the atmosphere by permissible explosives occurs with approximately 8.1 percent natural gas . The study also shows that incendivity of a permissible explosive cannot be determined only by its detonation velocity , oxygen balance , or ballistic mortar strength . However , for similar type explosives , trends observed indicate that their incendivity increases with detonation velocity or bulk strength . Additionally , for underoxidized explosives studied here , the more negative the oxygen balance the less incendive was the explosive within a class defined by salt content .

Jan 1, 1963

By B. H. Clemmons, B. G. Saunders, R. H. Stacy

"INTRODUCTION This investigation was undertaken to determine the response of Birmingham (Alabama) red-iron ore to heavy-medium concentration. Specifically, the work involved a study of the efficiency of the process in separating coarse gangue diluents from the ore and an endeavor to evaluate the potential economic results. The investigative work was not intended, nor is it to be construed, to be adequately exhaustive in scope to enable immediate plant construction. Rather, the primary objective was to determine the grade of ore that could be produced by heavy-medium treatment and the resulting indicative or tentative benefits to be derived from such treatment. The latter, in turn, would determine the merits of the more exhaustive study that would be required for an ultimate decision on the heavy-medium treatment of the ores.The problem of avoiding excessive contamination of red-iron ores by shale and/or ferruginous sandstone has been before the operators of the iron mining industry of the Birmingham, Alabama, district for many years. Within the last two decades, increased mechanization of mining methods has increased this contamination to a considerable degree. In fact, general utilization of scraper loading and other mechanical methods of mining, in conjunction with small increases in the natural insoluble content of the ores, in some cases has actually resulted in the production of ""acid"" or excessively insoluble ore, where ""basic"" or excessively lime ores were produced formerly.The contaminating materials are derived largely from roof spells and natural parting seams in the ore, a condition that to some extent has been aggravated by the irregularity of the ore beds. The latter have been subjected to both primary and secondary folding in many places. Considerable faulting has taken place, also. In many localities these conditions render virtually impossible complete avoidance of ore contamination from the over and underlying sandstones and shales. However, in a few localities, where the ore beds are less disturbed and shale partings are absent, mining can and is being accomplished with relatively little dilution."

May 1, 1948

By V. E. McKelvey

Any discussion of growth and future requirements has to begin with people--both their number and their needs. Both have been rising ever since any American can remember. Together, the number of people, which has been increasing rather modestly, and their wants and desires for material things, which have been increasing very sharply, seemed to have comprised a growth imperative in mineral consumption in the United States, especially during the last several decades. While the Nation's birthrate is now well below the replacement rate and still falling, the built-in momentum of the post-World War II population boom will continue to be felt well into the 21st century. Even using the modest projection of a 0.8 percent yearly increase, we are still looking at the possibility of 265 million Americans being around by Year 2000.

Jan 1, 1975

By S. H. Lorain

Tin mining on Seward Peninsula, Alaska, has been intermittently active since the early 1900's. Most of the recorded production (over 2,200 short tons of metallic tin) has been obtained from placer deposits, but recent production also has resulted from development of lode deposits associated with intrusive rocks occurring in the western part of the peninsula. Generally, the lode deposits containing tin minerals (principally cassiterite) are found in dikes, in granite masses, and in silicate zones in limestone overlying the granite. Both the placer and lode deposits have been of considerable strategic interest to the Government because of the almost total absence of a domestic supply of tin. The most important tin-lode deposit discovered to date is in the Cassiterite dike at the Lost River mine, on Cassiterite Creek about 85 miles northwest of Nome. This highly altered, rhyolite porphyry dike averages 12 feet in thickness, strikes N. 75° to 85° E., and dips steeply to the south; it can be traced on the surface for about 8,000 feet. Throughout its explored length of about 2,200 feet the dike everywhere contains some tin and tungsten in veinlets and disseminations; economic concentration of the are minerals, however, is confined to definite shoots. The ore minerals include cassiterite, stannite, hulsite, paigeite, wolframite, scheelite, and base-metal sulfides; gangue minerals include fluorite, boron silicates, and lithium-bearing minerals. Some ore minerals also occur in the numerous other dikes and in the granite and intruded limestone in and adjacent to the mine.

Jan 1, 1958

By W. W. Adams

Every man-hour of work performed in and about the coal mines of the United States had a 2-percent heavier death load from accidents in 1938 than in 1937. This is an unorthodox way of stating that the death rate per million man-hours of exposure or employment was 2 percent higher in 1938 than in 1937, increasing from 1.74 to 1.78. Thus the average miner had a 2-percent greater chance of being killed in 1938 than he had in 1937. The average quantity of coal resulting from 1 man-hour of work increased 3.6 percent -from 0.615 ton in 1937 to 0.637 ton in 1938. The production of the average ton of coal was accompanied by a slightly smaller loss of life in 1938 than in 1937, the accident rate being 2.793 per million tons in 1938 compared with 2.833 in 1937.

Jan 1, 1941

By J. V. Batty

Radioisotopes of selenium (se78) and tellurium (Te123) were successfully employed by the Bureau of Mines as tracers in metallurgical research directed to developing improved methods for volatilizing these elements from low-tenor raw materials. Prior research, guided and controlled by conventional analytical methods, was seriously hampered by inconsistent selenium and tellurium analyses, by the slowness of the conventional chemical methods, and by the poor accountability of these volatile elements in test products. Methods were devised and evaluated for admixing the radioactive tracer with typical raw materials and then following the deportment of the selenium and tellurium by radiometric methods with occasional chemical analysis checks. These techniques were found unusually effective in (1) quantifying the completeness and the rate of volatilization of selenium and tellurium while heating the raw materials at different rates to different temperatures and (2) accurately tracing and quantifying the distribution of minute amounts of these volatile elements in the several products made by high-temperature treatment and in the several units comprising the experimental equipment.

Jan 1, 1962