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By J. E. Tiffany

A stick of explosive is a package of stored energy that can be released when needed to blast rocks, coal, and other materials; but, unlike fuels such as coal and gasoline, its potential energy is self-contained, there being enough oxygen within the package to complete the almost instantaneous reaction. When an explosive is ignited or detonated, the solid or liquid materials of which it is composed are converted rapidly into highly heated gases, which, if free to expand, would have a volume many times larger than that of the original explosive. At the instant of explosion these gases occupy only the volume of the shot hole and are therefore produced at a very high pressure, which causes the material that is being blasted to be broken or disrupted. In blasting coal efficiently the proper placement of the shot hole and the confinement of the explosive therein are both of prime importance. When these are not adjusted properly, only a small amount of the energy is expended in bringing down coal, consequently the balance of the energy tends to be expended by the emission of a flame into the working place that may lead to a gas or dust explosion. Permissible Explosives Defined The term "permissible explosive", as applied by the Bureau of Mines to explosives it has approved for use in blasting in coal mines, embraces not only the requirement that the explosive, when used, shall be similar in all respects to the basic sample that passed all the tests necessary for its admission to the published permissible list, but also that the explosive shall be used under certain prescribed requirements.

Jan 1, 1938

By E. C. Pattee

A mobile spectroscopic laboratory was completed by the Bureau of Mines in 195 to provide a rapid, inexpensive means of field testing samples for beryl¬lium and other associated metals of possible commercial importance. Spectro-copes have been used in laboratories for many years in various types of research and routine analyses, but this spectroscope is probably the first mobile unit. The laboratory provides for spectroscopic, radioactivity, fluorescent, and limited chemical tests of samples. The unit has been a valuable reconnaissance tool. It has been used to search for beryllium, cesium, columbium, tantalum, rubidium, and lithium in Idaho, Washington, and Montana. Several very low grade deposits of these elements were found, and occurrences of other important elements were identified; however, none are of economic importance. The spectroscope permits the detection of elements by analysis of visible light produced when elements in a small powdered sample are volatilized in an electric arc., A total of 70 elements can be detected; 29 can be detected at or below 0.01 percent, Electric power for the arc is supplied by a gasoline motor-driven generator, Equipment is housed in an aluminum van, mounted on a 4-wheel-drive vehicle for easy maneuverability on mountain roads, A trailer with crushing, pulverizing, and splitting equipment permits the reduction of samples to a small representative pulp.

Jan 1, 1963

By H. W. Kilau

The Bureau of Mines used a high-temperature rotational viscometer to test basic oxygen furnace slags to determine fluorspar requirements and to evaluate colemanite and fused boric acid as substitute fluidizers. A continuous technique of viscosity measurement was adapted to better determine the viscosity-temperature profiles of volatile fluorspar slags. Criteria used for estimating slag fluidizer effectiveness were (1) the apparent solidification temperature, and (2) the temperature range of slag crystallization. Colemanite and fused boric acid in high-basicity slag were superior fluidizers to fluorspar when compared on the basis of boron versus fluorine concentration. Fused boric acid was nearly equivalent to ceramic-grade fluorspar when compared on a simple weight basis, while colemanite was inferior to fluorspar. Fluorspar slags volatilized fluorine during viscosity testing. Colemanite and fused boric acid slags were stable, no boron losses being detected. A fluidizing limit was found for fluorspar at 2.9 percent fluorine concentration; higher concentrations impaired viscosity and caused foaming and crusting of slag. Concentrations of boron up to 4.4 percent resulted in very fluid slags with no fluidizing limit.

Jan 1, 1978

By H. A. Doerner

For the past three or four years attention has been attracted to the deposits of lead vanadate in the Goodsprings , Nevada , district . Some ore running as high as 9 per cent 205 has been produced , but most of it runs from 0.5 to 3 per cent . Only a little ore , and that of the richer sort , has been shipped , since the low- grade ore will not stend the cost of shipment and no concentration mill has been available . Preliminary experiments indicate that chemical treatment of the low- grade ore without concentration is not feasible . Its treatment therefore involves two distinct problems ; first , mechanical concentration ; and second , a smelting or chemical treatment to obtain the lead and vanadium in marketable form . Upon this basis the work has been conducted . The writer wishes to acknowledge the excellent work done by J. T. Norton and Virgil Miller on table concentration and by J. E. Conley , who suggested and did preliminary work on the direct smelting method . Many helpful suggestions were received from Dr. S. C. Lind and John Gross of the Bureau of Mines . The ores were furnished by Mr. Frank Williams and Mr. James Ewing .

Jan 1, 1923

By A. Sainato, S. J. Schatzel, D. M. Hyman, J. C. LaScola

The Bureau of Mines determined the gas contents of 135 oil shale samples obtained from approximately 630 ft of core drilling. Drilling was done within a projected mining zone of the Cathedral Sluffs Mine, located in the Piceance Basin of western Colorado. Methane contents were determined by the modified direct method, which can measure the volumes of several gases released from or reacted with mine rock without destructive sample treatment. Over the duration of the test, nitrogen was largely unreactive, CO2 increased slightly, oxygen decreased markedly, and methane increased more than the total increase of all contained gases. The gas volumes were normalized per unit sample mass and are given in cubic centimeters per gram. Common time irzdices for test duration of 3, 40, and 125 days were used to compare methane desorption among samples. The means of the sample populations for these indices were 0.0316, 0.114, and 0.195 cm3/g, respectively. These quantities are lower than those reported in a Bureau emissions study at the Horse Draw Mine in the Piceance Basin. Oil shale samples that were gas enriched beyond the mean methane contents frequently contained bitumens and pyrite.

Jan 1, 1987

By E. V. Cilento, K. A. DiGregorio, R. C. Lantz

"K. A. DIGREGORIO, E. v. CILENTO, AND R. c. LANTZ. Measurement of superoxide release from single pulmonary alueolar macrophages. Am. J . Physiol. 252 (Cell Physiol. 21 ): C677-C683, 1987.-An electrooptical method was developed to quantify superoxide (02) release from single rat pulmonary alveolar macrophages (PAM) during adherence to the bottom of a culture dish. This was done by measuring the reduction of nitro blue tetrazolium (NBT) to a diformazan precipitate at 550 nm from videorecorded images of individual cells. Temporal changes in cell optical density, which are proportional to the mass of diformazan produced, were calculated from videophotometric measurements of the change in light intensity over individual cells. Total diformazan produced increased 78 and 1263 with an increase in NBT from 0.5 to 1.0 and 2.0 mg/ml, respectively. Total diformazan produced and maximum rate of production among individual PAM varied two- to threefold providing strong evidence for heterogeneity in 02 production. Specific inhibition of 02 production by superoxide dismutase, iodoacetate, and chlorpromazine significantly reduced the total diformazan produced and maximum rate of diformazan production. Hydrogen peroxide was not involved in NBT reduction, since catalase alone did not significantly change diformazan production. This novel method to quantify 02 release from single PAM should be valuable in analyzing heterogeneity and single cell kinetics of O; production, in assessing the effects of exposure of cells to particulates on O; release, and in relating release to electrophysiological measurements.rat; nitro blue tetrazolium; macrophage heterogeneity; single cell kinetic PULMONARY ALVEOLAR MACROPHAGES (PAM) protect the lungs by phagocytizing foreign debris and bacteria (24). This process involves ingestion as well as destruction of foreign matter. Phagocytosis is usually accompanied by a respiratory burst that increases cellular oxygen consumption and glucose metabolism in the hexose monophosphate shunt (7), which leads to the release of highly reactive oxygen metabolites at the surface of the · plasma membrane (6, 27). These agents have been implicated in the killing of bacteria by phagocytes (22), but have also been shown to be toxic and have been linked to cancer, emphysema, arthritis, diabetes, and other diseases (17, 22, 30). Toxic effects may be a result of either an abnormally low production of metabolites, resulting in damage to lung tissue by respirable bacteria and dusts, or an abnormally high production, resulting in direct damage to lung tissue by metabolites themselves."

Jan 1, 1989

By C. E. Julihn

In the past few years the advance of the Sunshine mine to national prominence as the chief silver-producing mine of the United States has revived interest in the area in which it is situated. Although this area lies between the great lead-Zinc-silver mines at Kellogg and those in the vicinity of Burke and Mullan it was generally presumed to be almost barren, as little ore had been found there until substantial ore bodies were developed on deep levels of the Sunshine mine. In early days it was called the "dry belt" because its ores were siliceous and contained little lead; but the classification of ores in smelting as wet or dry, although once customary, has long been obsolete The area will therefore be referred to in this paper as the silver belt of the Coeur d'Alene district because the value of its ore is due chiefly to silver, the current production of which is large, providing over 60 percent of the silver output of Idaho. Silver Belt - Its Limits and Character With a daily production of half a ten of silver or more from the Sunshine mine, the silver belt has become the scene of extensive exploration at many properties, and the outlook for its future seems promising enough to warrant the lively interest now being displayed in the area by the public.

Jan 1, 1936

By Donald F. Reed

In its investigation of old, abandoned, lead-zinc mines at which records of operations are not available, in 1914 the Bureau of Mines dug surface trenches anti', in 1947 It diamond-drilled three holes at the Albright Farm deposit in Sinking Valley. Some good lead-zinc ore had been extracted from veins in dolomitic limestone during the time of the American Revolution and as late as 1870. Since that time the only activity was sporadic prospecting and developing. Thu Bureau of Mines disclosed two additional veins by surface trenching, but diamond drilling failed to find significant lead-zinc mineralization.

Jan 1, 1949

By G. R. Hopkins

According to reports as of January 1, 1931, the total daily charging capacity of the cracking plants, hoth completed and under construction, in the United States amounted to 1,950,781 "barrels, an increase over the previous year of 14 per cent. The total daily capacity of the operating plants amounted to 1,594,990 "barrels, or 82 per cent of the grand total, the capacity of the in¬ operative plants was 244,661 "barrels, or 12 per cent of the total, while the capacity of the plants under construction amounted to 111,130 "barrels, or 6 per cent. In comparison with a year ago, these data indicate a decline in the total capacity of the plants "being "built "but show material increases in the capacity of "both the other two classes. The increase in total inoperative capacity and the decline in construction in 1930 undoubtedly resulted from un¬ satisfactory economic conditions. The total number of cracking units completed or under construction on January 1, 1931, totaled 1,863 as compared with 2,002 the previous year and with a high of 2,559 on June 1, 1926. During the period between June 1, 1926, and January 1, 1931, the total charging capacity of the cracking plants has more than doubled, but the number of units has shown a material decline. This condi¬ tion has been brought about largely through the dismantling of many Burton still of small capacity and through the tendency to increase the size of the new units The "largest unit that can be identified in this survey has a daily charging capacity of 10,000 barrels, but undoubtedly there are some that would exceed this in size. Texas, with a total of 575,300 barrels, ranked far ahead of the other States in charging capacity, and was followed in order by California, Indiana, Oklahoma, and Pennsylvania. Indiana, with only five refineries, ranked third in cracking capacity, which illustrates the importance of the Chicago district as a gasoline-producing center. Not all of the States showed a gain in capacity during the year; in fact, four of them, namely Illinois, Louisiana, New York, and Oklahoma, reported a decline.

Jun 1, 1931

By Michael S. Miller

In 1986 and 1987, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied the 550-acre Carson-Iceberg Wilderness Study Area (NV-030-532), in order to evaluate its identified mineral resources. The Wilderness Study Area is located in Alpine County, CA, 11 mi southeast of Markleeville, CA. Tertiary volcanic and granitic rocks, as well as alluvium, underlie the area. Hydrothermal alteration and faulting have affected some rocks; argillic, silicic, and limonitic alteration are found, particularly near faults. No mineral resources were identified in the Wilderness Study Area. The area has one small pit and no mines or claims. Samples from the Wilderness Study Area and vicinity contained uneconomic amounts of gold, silver, copper, lead, zinc, mercury, arsenic, and molybdenum. Mineral occurrences are too small and low grade to be of interest within the foreseeable future.

Jan 1, 1988

By J. F. Barkley

At the request of several Federal agencies, tests were conducted on a relatively recent type of anthracite -burning equipment named the Anthratube. This device, rated at 130,000 B.t .u. per hour, was designed to burn Pea-size anthracite automatically for steam or hot-water house heating and for domes-tic hot -water supply. ACKNOWLEDGMENTS The helpful cooperation of the Anthracite Institute and the manufacturers of the equipment, Axeman-Anderson Co., Williamsport, Pa., is gratefully acknowledged.

Jan 1, 1953

By Edward J. Murphy

A comparative study has been made by the Bureau of Mines of several analytical methods for determining carbon monoxide and nitrogen oxides in toxic gases produced by the detonation of explosives. Laboratory and field methods and detector-tube devices are described. Analytical results are compared, and reliability of the various methods is discussed. INTRODUCTION In all underground mining there is ever-present danger to persons from possible overexposure to carbon monoxide and nitrogen oxides created by explosives or blasting agents. These health hazards, recognized for many years, led to the early establishment by the Bureau of Mines of specific requirements regarding fumes generated by explosives authorized for use in underground coal mines in the United States.3

Jan 1, 1961

By Phillip R. Moyle

In 1985 the U.S. Bureau of Mines evaluated the mineral resources of the Sheep Creek West Wilderness Study Area (ID-111-36A), Owyhee County, ID, for the U.S. Bureau of Land Management. The Wilderness Study Area consists of 11,680 acres centered approximately 20 miles south of Grasmere, 10. It contains no mines, claims, or prospects. No mineral resources were identified; however, a geode occurrence within and adjacent to the Wilderness Study Area, and minor amounts of placer gold along Sheep Creek, may be of interest to rorkhounds and recreational gold panners.

Jan 1, 1986

By D. E. Stone

Solid and liquid impurities must be removed almost completely from synthesis gas for the production of synthetic liquid fuels because of their effect on the synthesis catalyst and turbocompressors. The maximum permissible concentration of dust has been set at 0.05 grain per 100 cubic feet.5/ This is one part per million by weight, or about the same concentration as in average city air. The cost of synthesis gas is estimated to constitute 60 to 70 percent of the total cost of the synthetic liquid fuel. For this reason this station is developing processes using coal instead of the more valuable coke as raw material, which promises reduction in cost of the synthesis gas. This, however, increases the difficulty of attaining the above dust value. As failure of the dust-removing equipment to produce high-purity gas may ruin valuable equipment within a few minutes, it is imperative that a reliable and continuous method be obtained for determining such extremely low concentrations .of dust in the purified gas. A suitable device must also instantly sound an alarm and, if necessary, automatically actuate the proper valves to prevent damage. The Ess Instrument Co. designed and built an instrument which they believed might fulfill these specifications. It' continually compared, by means of photoelectric cells, the intensity of a light beam passing through the gas and a similar beam passing through clean air. For maximum sensitivity, the photocells were connected back to back, i.e., anode to cathode and cathode to anode. The difference in voltage produced by the two cells was amplified and operated an indicator.

Jan 1, 1951

By G. W. Birge

The Bureau of Mines investigated the effect of temperature on the mechanical strength of cokes of the type normally used in blast furnace operations. Eight samples of industrially produced cokes were subjected to ASTM tumbler tests at temperatures as high as 1,100° C (2,012° F); these temperatures had no significant effect on tumbler results for cokes with stability indexes of 40.6 to 59.9. Two foundry cokes which were tested at only one elevated temperature (900° C) decreased slightly in tumbler stability. Iron are pellets made from a variety of ores and by various industrial methods were not significantly affected by temperature when tested in an oxidizing atmosphere at 1,000° C (1,832° F) by the tentative standard ASTM method.

Jan 1, 1966

By Steven R. Munts

In 1985, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied 8,445 acres of the 20,650-acre Tunnison Mountain Wilderness Study Area in order to evaluate its identified mi nerd 1 resources. The study area is located in Lassen County, CA, about 8 miles northeast from Susanville. No mineral resources were identified in the study area based on literature, field observations, and sample results. No mines were operating in or near the study area in 1985, and no mines, prospects, or claims have been located in or within 1 mi le of the study area. The study area is underlain by Pliocene and Pleistocene volcanic units composed of basalt, andesite, rhyolite, and some pyroclastics. No metallic and only nonmetallic commodities are present in the study area. These included stone and sand and gravel. Although substantial volumes of basalt and andesite (stone) occur within the study area, no identified resources of these commodities were delineated. Sand and gravel is not economic because of small occurrence size and lack of local markets.

Jan 1, 1987

To provide longwall operators with a method to predict methane emissions from panels with increased face width.

Jan 1, 1997

By R. D. Ladoo

"At the beginning of 1920 a general feeling of optimism was noted in many talc-producing districts. The industry seems to have recovered from the temporary depression of the first half of 1919 and many mills are running at capacity production with their entire output for 1920 contracted for. The imports of talc for 1919 were only slightly larger than in 1918 by weight and probably no more by value. Thus foreign competition has not begun to be seriously felt. Several new companies in this country have been organized, some to operate new deposits and others to continue the work done by others.An interesting phase of the present situation is the possibility of increased use of talc in paint. There is a shortage of barium sulfate used as,paint filler. Since, for some uses, talc is considered second only to BaSo4 as a filler for paint, it is possible that part of the shortage could be relieved by an increased use of talc.A series of physical tests upon all pigment materials used in the manufacture of paints is being conducted for the Paint Manufacturers Association of the United States. It is important that all types of talc be represented in these tests. Producers of finely ground talc, 200 mesh and finer, are urged to submit samples of at least two pounds each of these grades that are available to paint makers with trade name and quality data, to the Institute of Industrial Research, 19th & B Streets, Washington, D. C., where the tests are being conducted.The Talc Products Company, Inc., Washington Building, Los Angeles, California, has recently been organized to develop a large body of talc one mile north of Riggs, San Bernardino County, California, This deposit contains a compact, white talc which can be sawed into crayons. The company's mill, at Los Angeles) is equipped with a unit of the Raymond system of grinding and air separation, and pencil sawing machines. It is reported that the pencils are being successfully used in Pacific Coast ship yards.The mining of talc where no mill is owned by the operator and the consequent sale of talc in its crude massive state has not proved profitable in a number of cases recently noted. Under exceptional circumstances, where mining costs are low and the product can be sold to a mill near the mine, the operation maybe profitable, but this condition is not common. One mine of this type has recently closed down, at least temporarily; but a second, more fortunately situated, in another district, is continuing operations, although plans are being made to erect a mill in the early spring. Most satisfactory results are ordi¬narily obtained where the mine and mill are owned by the same company.The sale of the Balmat mine of the International Pulp Company, near Gouverneur, N. Y., to J. H. McLear, Gouverneur, and H. G. McLear of New York, has been reported. It is stated that a large part of the property has been already leased to the Sylvia Lake Company, who will operate it. ""Cement, Hill, and Quarry""* states that ""the first mining done on this property was for silver and lead, but it developed into a good zinc producing property and later it was worked for its talc deposits. It has passed through several hands, the American Pulp Co., the Union Talc Co., and the International Pulp Co., all having had it in successive periods since 1891."""

Jan 1, 1920

By H. H. Schrenk

One phase of Bureau of Mines work in health and safety is promotion of the use of safe, satisfactory, and reliable respiratory protective devices. To insure that such devices will be. available, the Bureau has established schedules of minimum requirements for oxygen breathing apparatus,3/ gas masks,/ supplied-air respirators (hose masks, air-line, respirators, and abrasive blasting helmets, hoods, or masks),5/ and dispersoid (dust, fume, and mist)

Jan 1, 1943

By Ann G. Kim

Hydrocarbon gases, primarily methane but also the C2 through C5 paraffins, the C2 and C3 olefins and possibly the C4 and C5 olefins, are byproducts of coal formation. Although it is generally believed that coal formation occurred at temperatures below 200° C, most experimental work on gas formation from coal has been performed at temperatures between 200° and 1,000°C. The objective of this Bureau of Mines experiment was to determine if observable changes in the gases from coal could be produced at temperatures below 200° C in relatively short periods of time. The experiment involved heating coal samples from six coalbeds at constant temperatures and analyzing evolved gases. The composition of the gases at three temperatures was compared. At 35° C, over 99 pct of the gas is methane; at 125° and 150°, methane constitutes approximately half of the hydrocarbon gas. Isobutane and pentane are the predominant higher hydrocarbons at temperatures between 100° and 150° C.

Jan 1, 1974