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By John Campbell, Miller. W. E., G. W. Jones

"INTRODUCTION Because of its interest in accident prevention, the Federal Bureau of Mines has cooperated with city officials and utilities in investigating the causes of explosions in sewers, manholes, and other underground spaces and has aided in the development of means to prevent such explosions. For several years this Bureau has cooperated with the Boston Edison Co. and the Boston Consolidated Gas Co. of Boston, Mass.,for the purpose of detecting and eliminating combustible and physiologically harmful gases in manholes in Boston and vicinity.These investigations 5/ have shown that combustible gases from the usual sources — leakage from gas—distributing systems and underground tanks and gasoline wastes — can be located and the dangerous conditions remedied by a well—planned, adequately supervised, systematic, and continuous manhole survey. However, other types of gas contamination, termed ""soil"" gases, are present in manholes at times and are more difficult to eliminate because they have no fixed origin and because seasonal and barometric chances affect their production and passage into the manhole. Soil gases usually are abnormally high in carbon dioxide and low in oxygen and contain varying amounts of methane. They are especially dangerous to men entering manholes because they lack sufficient oxygen to support life."

Feb 1, 1940

By McHenry Mosier

A skull breaker has demonstrated its advantages for secondary breaking in a limestone quarry by entirely displacing secondary blasting . It has reduced safety hazards to workmen, increased the number of quarry operating days , and has lowered mining costs by 2.7 cents a ton. It is believed that the application of the skull breaker can be made economically advantageous in the surface mining of other commoditics .

Aug 1, 1948

By William J. Wuest

The technical analysis of parameters that can influence roof and rib reinforcement is important to the operation of safe and profitable underground mines. One such parameter, studied in this U.S. Bureau of Mines investigation, is the effect of time on untensioned, resin-grouted bolt anchorage characteristics. A group of seventy-three 4-ft-long bolts with three different grout column lengths were I installed in a stable coal mine roof. The bolts were then subjected to standardized pull tests at various intervals throughout a 37-month period. For each test, load-deformation data were reduced to determine axial stiffness and yield point. The magnitudes of these two anchorage characteristics at the time of installation were compared with results from subsequent pull tests to determine if anchorage capacity deteriorated. Bolts with 18-in grout columns were studied over 9 months, and no measurable loss occurred. Bolts with 48-and 24-in grout columns were studied over 37 months and also exhibited no measurable loss.

Jan 1, 2010

By Raymond M. Stateham

The Bureau of Mines evaluated temperature increases on the heads of resin-grouted bolts as indicators of the integrity of the anchoring of the bolt. Expected increases were calculated by the finite difference method; the calculations were checked by bolthead temperature measurements, both in the laboratory and in the field. The accuracy of the calculations varies with the validity of assumptions necessary to the process. Measurements in the laboratory produced a temperature rise of about 4.00 F on the head of a 4-foot bolt when installed with a full column of resin. This increase remained for about 30 minutes. Similar increases were noted on bolts installed at the White Pine mine, White Pine, Mich., but bolthead temperature increases in the mine lasted only about 10 to 15 minutes. When partial columns (reduced amounts) were used, the temperature increases were smaller.

Jan 1, 1976

By D. Harrington

While apparently the hysteria with regard to silicosis and other occupational diseases has largely subsided and this subject is being more carefully considered and soberly judged, it would be poor policy for any employer to maintain that the storm has ended and that he can relax and revert to conditions as they were 5, 10, or more years ago. The fact is that the plan of paying occupational-disease compensation is now in its infancy and can be expected to grow rapidly. At present, while all of the States of the Union, including the District of Columbia and excepting only Arkansas and Mississippi, have compensation acts, only the following make provision for occupational diseases to some extent or in one way or another: California, Delaware, Connecticut, District of Columbia? Illinois, Indiana, Kentucky, Massachusetts, Michigan, Minnesota, Missouri, Nebraska, New Jersey, New York, North Carolina, North Dakota, Ohio, Pennsylvania, Rhode Island, Washington, West Virginia, and Wisconsin. Silicosis is compensable in one way or another in California, Connecticut, District of Columbia, Illinois, Kentucky, Massachusetts, Missouri, New York, North Carolina, North Dakota, Ohio, Pennsylvania, West Virginia, and Wisconsin, and possibly in other States. During the past few months, occupational-disease legislation (largely silicosis) has been considered in some form in Arkansas, California, Delaware, Idaho, Maryland, Kansas, Massachusetts, Michigan, Minnesota, Montana, Nebraska, New Jersey, Ohio, Pennsylvania, Tennessee, Utah and Washington. It will be surprising if comparatively comprehensive occupational-disease legislation is not on the statute books of nearly every State in the Union within the next 5 years. With this situation confronting him, the farsighted industrialist who has the interest of his organization at heart, if he has not already done so will immediately start to "put his house in order" by studying possible occupational disease hazards to his employees and promptly applying known remedial measures or attempting to devise such measures if none exist. Unquestionably, one of the most important of the surveys to be made relates to dust occurrence, as State laws on occupational disease are almost certain to contain provisions, on silicosis and, with almost equal certainty, the provisions of any State law are not likely to be particularly similar to those of other States.

Jan 1, 1938

By Wesley A. Grosh

The Vest nickel prospect, in Floyd County, Va., was discovered about 25 years ago. Limited exploration of the deposit had indicated some appreciable nickel mineralization in the sulfide ore. The property was examined on March 9, 1943, by an engineer of the Bureau of Mines in company with C. W. Vest, owner of the property. A limited exploration program was recommended. Two holes totaling 320 feet were diamond-drilled in January 1944. Drilling indicated the sulfides are sparsely disseminated. The only nickel values of interest were at the old prospect shaft.

Jan 1, 1949

By W. W. Agey

The Calico silver-barite deposits near Barstow, Calif., are a potentially important resource. Exploration performed by two major mining companies out-lined large tonnages of ore that assayed at 2 to 3 ounces of silver per ton and 7 to 15 percent barite. Laboratory beneficiation work was done by the Bureau of Mines on four samples to develop methods for recovering the silver and/or barite. Cyanidation recovered from 47 to 60 percent of the silver from ore ground to approximately 100 percent minus 325 mesh. Salt roasting minus 10-mesh material, followed by regrinding and cyanidation, recovered 75 to 85 percent of the silver. From 75 to 90 percent of the barite was recovered in a plus 92-percent barite product from either the natural ore or from cyanidation residues. Salt roasting before cyanidation precluded recovery of the high-grade barite concentrate from the leach tails.

Jan 1, 1973

By J. L. Stauffer, S. L. Lacey, L. J. Gaydos, L. M. Demers, D. C. Kuhn

"Tumor necrosis factor alpha (TNFa) and thromboxane A2 (TXA2) are major products of the activated alveolar macrophage and serve as key mediators of lung injury. In order to determine if the synthesis ofTXA2 and the release ofTNFa are associated, the production of these inflammatory agents by the human alveolar macrophage (AM), as a result of activation by lipopolysaccharide (LPS), was assessed in the absence and presence of the thromboxane synthase inhibitors UK 38,485 (Dazmegrel) and OKY 046. UK 38,485 and OKY 046 inhibited both LPS-stimulated TXA2 production and TNFa release in a dose-dependent manner. Prostaglandin E2 (PGE2) production was not increased by UK 38,485 or OKY 046. Neither LPS nor UK 38,485 had any effect on LT84 production by AM. Neither UK 38,485 or OKY 046 had any effect on LPS-stimulated interleukin-I beta release. However, the TXA2 mimetic, U46619, did not stimulate TNFa release by AM either in the absence or presence of UK 38,485. These findings suggest that 1) UK 38,485 and OKY 046 are inhibitors of both TXA2 production and TNFa release by activated human AM, 2) UK 38,485 probably does not exert its inhibitory action on TNFa release through effects on eicosanoid production and 3) the possibility that TNFa- and TXA2-induced lung injury may be subject to amelioration by imidazole-based compounds should be further evaluated.IntroductionTumor necrosis factor alpha (TNFa), produced by monocytes and macrophages, is a potent peptide mediator of lung injury (1,2). The exaggerated release of TNFa has been implicated in the etiology of acute lung reactions such as septic shock of bacterial or viral origin (3,4). The role of TNFa is expressed primarily through its ability to activate a variety of cell types within the lung environment including polymorphonuclear leukocytes (PMNs, ref. 5), type II epithelial cells (6) and fibroblasts (7). The role of lipid mediators in lung disease has also been extensively characterized (1). In particular, the relationship between pulmonary inflammation and fibrosis and the production of oxygenated derivatives of arachidonic acid (here termed ""eicosanoids"") appears to be a key factor in a variety of disease processes in the lung (8). The alveolar macrophage (AM) synthesizes primarily prostaglandin E2 (PGE2). thromboxane A2 (TXA2) and leukotriene 84 (LT84, ref. 9). These eicosanoids have been shown to produce a variety of effects in the lung including bronchial smooth muscle dilatation (PGE2, ref. 10), vascular smooth muscle contraction and platelet aggregation (TXA2, ref. 11) and oedema and immune cell extravasation (LT84, ref. 12)."

Nov 1, 1995

By D. P. Desmond

The U.S. Bureau of Mines investigated leaching automobile catalysts with sodium cyanide (NaCN) solutions at high temperatures to recover platinum-group metals (PGM). The feed was virgin monolith rejects, used monolith, and used pellet catalysts. Leaching with a 5-pct NaCN solution for 1 h at 160° C dissolved over 97 pct of the PGM in the virgin monolith, over 85 pct of the PGM in the used monolith, and over 90 pct of the PGM in the used pellet catalyst. Over 99.8 pct of the dissolved PGM was recovered as a precipitate by heating the solution to 250° C for 1 h in an autoclave. The cyanide complexes were decomposed, and free cyanide was destroyed.

Jan 1, 2010

By B. W. Naugle

This report describes the carbonizing properties of coals from the principal beds in Cambria County, Pa. Samples of coals from Upper and Lower Freeport and Upper and Lower Kittanning beds having estimated minable reserves of 50-million tons or more were studied by the Bureau of Mines. Cambria County coals rank either as medium-or low-volatile bituminous. A preparation study indicated that all coals tested in this county, except one sample from the Lower Freeport bed, were responsive to cleaning and would yield a product with satisfactory chemical properties for metallurgical coal. All coals tested from Cambria County yielded strong coke; however, they expand excessively when carbonized singly, and should be used only as minor constituents in metallurgical coking blends when carbonized in slot-type ovens.

Jan 1, 1959

By David E. Siskind

The Bureau of Mines recorded particle accelerations in the mine roof produced by three types of explosives in the Pilot Knob Pellet Co. mine, Pilot Knob, Mo. Examined were the effectiveness of cube root, square root, and two-thirds power scaling in grouping the underground blast vibration data, and the effects of mine geometry, rock type, explosive type, and charge size on blast vibration levels. A propagation law for this mine was determined. The scaling factor of the square root of the charge weight was developed from previous Bureau studies of vibrations from quarry blasts, and in under-ground blasting both square root and cube root scaling were found applicable for scaling particle vibration data. The vibrations from the Pilot Knob blasts were best grouped by a square-root scaling factor. The empirical propagation equation AW1/2 = 76,250 (R/W1/2)-2.61 where A is the peak acceleration in g's, W is the charge weight in pounds, and R is the distance from the blast in feet, may be used to describe vibration amplitudes from charges fired with zero delay caps or with a single cap at Pilot Knob. Statistically significant differences were found in the vibration levels generated by the different explosives. The Power Primer (75-percent weight-strength ammonia gelatin dynamite) produced levels of vibration of 1.7 to 2.4 times those of AN-FO and slurry explosives; the latter two are approximately equal.

Jan 1, 1973

By Helen W. Lang

This report describes a monitoring system applied by the Bureau of Mines to provide rapid, continuous determination of the main constituents of exhaust gas during the Bureau's approval schedule testing of diesel engines for under-ground use. Commercially available continuous analyzers with strip chart readout are employed for nitric oxide (mass spectrometric), carbon dioxide (nondispersive infrared), methane (NDIR), carbon monoxide (NDIR), and oxygen (polarographic). Good correlation is obtained between the continuous instrumental results and those obtained by batch chemical and gas chromatographic methods.

Jan 1, 1969

By Fredrick L. Johnson

In 1986, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied 25,640 acres of the 29,680-acre Devil?s Garden Lava Bed, 21,040 acres of the 28,660-acre Squaw Ridge Lava Bed, and 9,100 acres of the 12,600-acre Four Craters Lava Bed Wilderness Study Areas (OR-D01-D02, OR-001-003, and OR-001-022, respectively) in order to evaluate their identified mineral resources. The study areas are located in Lake County, OR, about 50 air miles southeast of Bend. No mineral resources were identified in the three study areas. The areas are almost entirely underlain by recent lava flows. Cinder cones occur in each of the areas; however, the best cinder occurrences are in the Four Craters Lava Bed study area. Slab lava, of facing stone quality, is scattered throughout the Devil?s Garden Lava Bed study area, and to a lesser extent, in the Squaw Ridge Lava Bed study area.

Jan 1, 1987

By R. P. Vinson

The Bureau of Mines examined the effects of high humidity and water droplets on the GCA Corp. real-time aerosol monitor (RAM--l). which uses a lO4mm cyclone preseparator. Tests were conducted both in a laboratory and in a full-scale model mine entry. The laboratory tests were conducted in a test chamber saturated with moisture and water droplets. Under these extreme conditions. the RAM-I responded by indicating dust concentrations of 1-1/2 to 2 mg/m3? although the air was dust free. Within the first 2 h of each test. water accumulated in the cyclone and affected the cyclone particle separation characteristics. resulting in readings of 3 to 4 mg/m3. In addition. condensation formed inside the RAM-I case and affected the liquid crystal display (LCD). However. the full-scale mine entry tests revealed that the RAM-I can function ac-ceptably in an atmosphere of water vapor and water droplets similar to the most severe conditions found in an underground mine.

Jan 1, 1984

By Stuart Bjorklund

This paper is one of many reporting various aspects of the Bureau of Mines program initiated in August 1939 by passage of the Strategic Minerals Act J the scope of which was greatly expanded by subsequent legislation. In its program of investigation 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. The occurrence of chromite in the Knik Valley near Palmer, Alaska, was brought to the attention of the Bureau of Mines in September 1941 by George Johnson, of Anchorage. At that time a preliminary investigation was made by Robert S. Sanford, an engineer of the Bureau of Mines. The area was investigated on June 4 and 5, 1943, by Henry R. Joesting and Leo H. Saarela, engineers of the Territorial Department of Mines. In August 1942, a second chromite occurrence, the Highway deposit, in the Knik Valley, was reported to the Territorial Department of Mines by John E. Ryan of Anchorage.

Jan 1, 1948

By A. E. Harak

To determine the retorting characteristics of a column of mine-run, ungraded oil shale ranging in size from fines to pieces weighing as much as 5 tons, a 150-ton batch retort was designed and constructed at the Laramie Energy Research Center, Laramie, Wyo. The retort vessel is 45 feet high by 11-1/2 feel in inside diameter and is supported in a 92-Foot-high steel superstructure. Mine-run shale from the Bureau of Mines facility near Rifle, Colo., assaying about 25 gallons of oil per ton, is currently being used as the test shale. To date, three runs have been completed. Results of the second and third runs are reported in this paper. The two runs considered in this report are the first of a series of nine to determine operating conditions that will yield maximum oil recovery from a column of mine-run shale. Variables studied :ire the oxygen content of the retorting gas and the space velocity of the retorting gas expressed as ft3 gas/ft3 bed/min. Oil recoveries for the two runs reported are 62.2 volume percent of Fischer assay for the run using higher oxygen and space velocity, compared with 39.3 volume-percent when less oxygen and a Lower space velocity were used.

Jan 1, 1971

By Joseph M. Pugliese

The U.S. Bureau of Mines has produced a generic in situ copper mine design manual, which contains a computerized cost model for in situ copper oxide mining. The model specifies (1) site-specific parameters, which must be quantified for mine design, (2) a method for minesite design based on those parameters, and (3) a procedure for assessing economic viability for the mine design. The menu-driven computer program performs calculations for developing commercial mine design specifications, as well as capital and operating costs. The default values are based on 1986 dollars, and indices for updating costs are included. The program also provides discounted-cash-flow rate of return (DCFROR) and allows for sensitivity analyses for an in situ mining operation at any specific undisturbed copper oxide deposit. This report is to be used with the 1990 version of the computer program, which has been made user friendly. It describes the flies, tutorial, input phase, help function, and monitor display of all calculated values and of the DCFROR table. The monitor-displayed discounted initial value of investment and annual operating costs are defined. The dual rate-of-return situation and sensitivity analyses are also briefly discussed. Information is provided on obtaining the computer program on diskette.

Jan 1, 1991

By K. K. Kelley, L. B. Pankratz, W. W. Weller

Mullite is a substance of prime importance in ceramic technology . Despite this fact , its thermodynamic properties have received little attention . A Bureau of Mines literature survey disclosed the absence of lowtemperature heat capacity data , the absence of an experimental entropy value for 298.15 ° K , and the lack of heat content data beyond the temperature range from 298° to 576 ° K. Data supplied in this Bureau report fill these gaps in the thermodynamic knowledge of mullite . According to equilibrium phase studies of Aramaki and Roy ,3 the mullite phase melts congruently at 2,123 ± 15 ° K , and the equilibrium crystallinephase composition extends from Al Si2013 to Al6.8 Si₂ Q4.2 . The results in this report are for the stoichiometric composition , Al Si¿Qз . • Heat capacity measurements were made over the temperature range from 50 ° to 298 ° K , and the entropy at 298.15 ° K was evaluated . Heat content measurements covered the temperature range from 298 ° to 1,800 ° K. Heat content

Jan 1, 1963

By Eugene Frey

The Romur is one of several properties in the Copper Mountain mining district, Fremont County, Wyo., that contain scheelite deposits. The district lies on the southern slope of the Bridger Mountains, 18 miles northeast of Shoshoni and 15 miles from the rail point at Bonneville on the Chicago, Burlington & Quincy Railroad (figs. 1 and 2). The tungsten deposits occur in a zone of pre-Cambrian schists and gneisses that have been cut by numerous basic dikes and granite pegmatite dikes. Scheelite occurs in lenses and pods that lie parallel to the foliation and bedding in the metamorphic rocks. The more important deposits are found in a lime-silicate rock consisting primarily of zoisite but with small quantities of quartz and carbonate. Scheelite was found in December 1941, and the area was mapped by the U. S. Geological Survey early in 1942. In November 1942 the Bureau of Mines commenced work on the Stardust-Comet group for the purpose of developing reserves for war requirements. The initial work consisted of driving an alit in the ore zone a distance of 109 feet. This zone was sampled during the progress of the work, and subsequently surface and underground exposures on adjoining properties also were sampled (figs: 5, 6, 7, and 8). One hundred twenty-four samples were obtained. Sample and assay data are shown in tables 2, 3, and 4.

Jan 1, 1950

By Lawrence W. Scott

The performance of RETIMET metal foam as a flame arrester on explosion-proof enclosures was investigated by the U.S. Bureau of Mines both in laboratory tests and at the U.S. Mine Safety and Health Administration's (MSHA's) Approval and Certification Center, Triadelphia, WV. The objective of this research was to develop a permissible pressure vent for use on lightweight, vented, explosion-proof enclosures. In laboratory tests, four grades of RETIMET, a stainless steel foam material, were evaluated: (1) 45 NC-7, (2) 45 NC-13, (3) 80 NC-7, and (4) 80 NC-13. Explosive gas mixtures were prepared by a dynamic flow system. Ignition was by a low-voltage arc. Each grade of RETIMET metal foam successfully arrested the flame front in all methane-air tests. To evaluate RETIMET metal foam on large, commercial size enclosures,a multi compartmented enclosure was designed and tested in MSHA's explosion gallery in Triadelphia, WV. Extensive explosion testing revealed that a minimum vent-area-to-enclosure-volume ratio of 11.33 in2/ft3 is required to keep internal pressure rises below 3 psig. The RETIMET metal foam functioned satisfactorily in all tests as evidenced by the absence of external ignitions.

Jan 1, 2010