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By R. A. Guereca

The Bureau of Mines conducted an analysis to determine criteria for steady-state, laminar flow boundary conditions for a coiled-tube gas viscosimeter by comparing experimental data from a thick-walled, stainless steel capillary in a horizontal, straight-tube condition, with similar data taken after the same capillary was formed into a helix. Overlapping volumetric f10wrates and pressure drops are covered for both configurations at pressure levels of 28, 225, and 1,000 psia at 3000 K. Friction factor, Reynolds number, and Dean number correlation plots show conditions where the coi1ed-tube flow deviates from straight-tube flow. The coiled-tube data indicate departure from Poiseui11e steady-state laminar flow at a Reynolds number close to 390 and a Dean number of about 15. Below these conditions and consistent with the data reported, Dean's circulation appears negligible. For the particular coil used, a conservative upper limit of 10 is chosen for the Dean number corresponding to an upper limit of about 250 for the Reynolds number.

Jan 1, 1967

By D. J. Bauer, V. E. Shaw

Bastnasite concentrate was processed to recover total rare - earth content and obtain high - purity ceric nitrate . Reaction of the concentrate with 45 percent caustic soda for 1 hour at 180 ° C in stainless steel vessels resulted in 99 - percent conversion to rare - earth hydroxides . A drying step followed by solution in nitric acid produced a tetravalent cerium fraction amenable to extraction with TBP . Single- stage separatory funnel experiments resulted in 90 -percent recovery of ceric nitrate at a purity of 99.9 percent . Fractional extraction in pressure - bubbler columns resulted in 98.5 - percent recovery of 99.5 -percent - pure ceric nitrate .

Jan 1, 1964

By R. W. METCALF, A. G. Charles, F. M. SHORE

To furnish the information frequently requested by producers and suppliers as to the fuel requirements of the Federal Government , the Bureau of Mines , with the cooperation of the consuming departments and establishments , has collected the data herein , showing the Government's fuel consumption during the fiscal year ended June 30 , 1930. The following tables show the quantities and kinds of fuels consumed by the Federal Government in each of its departments and their principal branches , in each State , and in Alaska , Hawaii , Panama Canal Zone , Porto Rico , and the Virgin Islands . The separate departments and establishments were asked to supply information for each Federal building or other plant and , as to vessel fuel , the amount loaded at each port of supply . Fuels consumed in internal combustion engines are not included . The report does not include fuels used by Post Offices of the fourth class , since their fuels are not purchased by the Federal Government but are covered by an allowance in each case for light and heat . In some cases the data supplied represent receipts , which are approximately equivalent to consumption . The present study is believed to be the first effort to bring together the data representing the Government's requirements for the various fuels which it consumes . Figures showing the coal consumed by the Federal Government were gathered for the year 1922. These data are shown in an article by O. P. Hood and R. H. Kudlich of the Bureau of Mines , contributed as a chapter to " Industrial Coal ; Purchase , Delivery and Storage , " published by the American Engineering Council . The figures of coal consumption presented herewith are approximately comparable with those published for 1922 , a relatively small difference being due to the fact that the 1922 figures include the Philippine Islands and all other territory in which any coal was consumed by the Government . At the present time , the only data on Government fuel consumption that are published regularly are those compiled by E. B. Swanson , chief economist of the petroleum economics division of the Bureau of Mines . These are published annually by the Bureau of Mines in " Sources and Distribution of Major Petroleum Products , Atlantic Coast States , " and by the bureau in cooperation with the American Petroleum Institute in the annual " National Survey of Fuel Oil Distribution . " It is believed that the data herewith will prove of interest and value to the fuel industries as well as to Government consumers and that it will also afford a basis for measuring future trends in the use of the various fuels by the Federal Government . Figures showing the quantities of the various kinds of fuels consumed by each of the executive departments and independent establishments , are given in Table 1. It should be noted that when one organization procures and delivers fuel to be consumed by other branches

Apr 1, 1932

By R. Burrell, N .. L. Lapp

"Except for asthma and pulmonary infections, the types of lung disease that have been of immunologic interest the longest are the various mineral pneumoconioses. Because of their chronicity, type of pathology produced, and well-known immunotoxic properties associated with the dusts inciting them, the pneumoconioses have long drawn attention to the possibility that the immune system has not only been modulated but that its effectors have possibly contributed to their pathogenesis. All of the mineral dusts reviewed here have definite immunomodulating properties and act on various cellular and molecular components of the immune system. Further, each has an immunotoxic potential to induce either hypersensitivity (as in the case of beryllium) or other types of immune injury. This article reviews the immunologic aspects of the four major occupational minerals that have an immunologic impact on the lung: asbestos (particularly chrysotile), silica or quartz, beryllium, and coal mine dust.These agents have many things in common, yet each is distinctive. Although the possibility still exists that these mineral particles can adsorb intrinsic tissue antigens or extrinsic organic antigens to their surfaces and initiate immune responses to the adsorbed antigens, only one, beryllium, can act as an antigen itself. Silica is a profound macrophage toxin and thereby exerts many effects on those factors controlled by macrophages. Asbestos has undergone the most immunologic studies resulting in a much dearer picture of how it may contribute to immunopathology. Coal mine dust is the agent about which least is known immunologically, partly because there is no such thing as purified coal mine dust or a standard by which coal mine dust can be defined. Indeed, there are studies that use only the dust from the ground coal itself, whereas other studies use the total dust collected from air samples of a working mine in the belief that other types of dusts (e.g., silica from roof bolt drilling, from sand ground on the rails by cars, and from surface drilling) contribute to the disease (Figs. 1 to 5). This properly is coal mine dust and is poorly characterized. Yet, workers exposed to these dusts share similar reactive characteristics and they may be considered collectively as well as individually."

Mar 1, 1992

By Lee Blackman

The Malheur-Jordan Resource Areas (MJRA?s) is a tract of approximately 6.5 million acres of federal and non-federal land in the southeast corner of Oregon. This study evaluated the Resource Areas' economically recoverable mineral potential based on geological estimates provided in the USGS report (Smith, 1994). The mineral terranes are believed by geologists to contain undiscovered resources. The geological data is probabilistic; with estimates of the possible number of deposits and their grades and tonnages. Possible future development scenarios range from no development to numerous mines. Based on the analysis performed on these terranes, the most likely (in a statistical sense) future scenario for the resource areas would include the potential for two medium sized, predominately gold, mines. These would supply direct and indirect employment of up to about a thousand workers.

Jan 1, 1995

By R. V. Ramani

"In this paper, the current status of respirable dust control in coal mine atmospheres is presented. The advancements in the engineering control of dust generation and entrainment, and of reducing the exposures are summarized. The results of the Health Surveillance Program are briefly reviewed. The results of research conducted in the Generic Mineral Technology Center for Respirable Dust are presented. The 1995 NIOSH criteria document on respirable coal mine dust is briefly reviewed. The fundamental scientific and engineering issues in need of research are discussed. A detailed bibliography is attached.IntroductionFor coal mines in the United States, the current permissible exposure limit (PEL) of 2mg/m3MRE-equivalent concentration (an 8-hour TWA concentration measured gravimetrically) was established by Public Law 91-173: the Federal Coal Mine Health and Safety of 1969 (the 1969 Coal Act). This standard is reduced when the respirable quartz content in the dust sample exceeds 5%; the reduced standard in mglm3 is obtained by dividing 10 by the percent quartz. The OSHA and ACGIB PEL for respirable coal mine dust is also 2 mg/m3 , and OSHA PEL for respirable quartz is 100 µg/m3 . The 1969 Coal Act also prescribed two activities in the Coal Mine Respirable Dust Sampling Program and the National Coal Workers' Health Surveillance Program n to control respirable dust in mines, and the coal worker's pneumoconiosis (CWP) among the coal miners.There are three principal methods by which personal exposures to respirable dust are controlled. The first is engineering control where the aim is to reduce the concentration in the mine atmosphere to or below the mandated level. The second is the provision of personal protective devices which allow the miner to work in dusty atmospheres without increasing personal exposure. The third is the use of administrative controls where the miner's exposure is controlled through work schedules and procedures to keep miner exposure at or under the mandated levels. The 1969 Coal Act specifically prohibits the use of respirators in lieu of environmental control. The compliance sampling program essentially does not give any credit to the use of administrative controls."

Jan 1, 1998

By H. Dolezal

An investigation was made on the use of magnesium for the direct reduction of rutile to make low-cost, offgrade titanium which could be upgraded to an acceptable grade of metal by electrorefining. Reductions made with charges containing magnesium chloride under hydrogen yielded products with oxygen con-tests close to the theoretical equilibrium composition. Two reduction products were made from rutile for use in electrorefining amenability tests: (1) a product from reduction in an inert atmosphere which contained 88.9 percent titanium and 4.42 percent oxygen, and (2) a product from reduction in a hydro-gen atmosphere which contained 92.5 percent titanium and 2.40 percent oxygen. Reduction products obtained under both of these conditions were amenable to electrorefining.

Jan 1, 1965

By R. O. Dannenberg

This report describes aperiments by the Bureau of Mines and reviews theoretical aspects of the use of organophosphate solvent extraction for recovering beryllium from sulfate leach liquors. The leach liquors were prepared by sulfuric acid leaching of lime-sintered low-tenor beryl flotation concentrates. The experimental work on sulfate leach liquors showed that the acidic esters of organophosphates extracted beryllium slowly but in preference to aluminum. Three common alkylphosphoric acids, di- (2-ethylhexyl) (EHPA), heptadecyl (HDPA), and dodecyl (DDPA), in order of decrmsing selectivity, yielded a partial separation of beryllium from aluminum.

Jan 1, 1962

By L. G. Marshall

The geology, mining, beneficiating, types of products, and costs in terms of percent of total costs and of labor, power, and supplies of two crushed- limestone operations in Madison County, Iowa, are described in this paper. The operations are basically similar, differing in refinements in mining, product types, and markets. The operations are comparable as to personnel and as to weighted costs in terms of percent of total costs and in terms of man-hours, power, and supplies. The waste-to-stone stripping ratio is 1 to 0.8 at both operations, the powder factor is 0.29 pound of explosives per ton of stone, and daily production is 95 tons per man-shift. Both companies use crawler-mounted diesel shovels for loading, truck transportation, wagon drills, and dry screening.

Jan 1, 1963

By P. Wearden, K. Bryner, K. Vrana, V. Castranova, R. Dey, R. Reist, J. Blackford

"Summary: Fibroblast proliferation and enhancement of collagen synthesis are key steps in the development and progression of pulmonary fibrosis. The current investigation presents a fibroblast proliferation assay to detect the release of competence factors from pneumocytes. The specific objective of this study was to define cell culture conditions for fibroblasts that would allow selective detection of competence factors in test media. The results indicate the following: (a) fibroblasts should be cultured for 2 days in plasma-free medium rather than 2% plasma to assure complete quiescence; (b) 1% plasma was optimum for producing progression activity for the bioassay of a competence factor, while 0.5% plasma did not produce sufficient progression activity (yielding false negatives) and 2% plasma often contained significant competence activity (yielding false positives); and (c) fresh plasma should be used since the progression activity of plasma was adversely affected by freezing and thawing. Under these conditions, this bioassay can be employed with either rat or human lung fibroblasts to detect competence factors such as platelet-derived growth factor (PDGF), at levels as low as 25 ng/ml.Fibrotic lung disease, as a consequence of occupational exposure to silica dust. is characterized by the development of concentric hyalinized nodular lesions in the lung and the progressive loss of pulmonary diffusion capacity. Proliferation of pulmonary fibroblasts and enhanced synthesis of collagen by these pneumocytes have been shown to be key steps in the development of chronic silicosis ( 1 ). The regulation of lung fibroblast proliferation by cytokines released from alveolar macrophages may be an important pathogenetic mechanism in the development of the fibrotic process (2). Some cytokines stimulate fibroblast proliferation by activating specific phases of the cell cycle (3,4). In particular, platelet-derived growth factor (PDGF) promotes fibroblast proliferation by inducing the movement of quiescent (G0 ) cells into the G1 phase of the cell cycle (5). Insulin-like growth factor (IGF) and transforming growth factor-P (TGF-P). on the other hand, regulate the rate of transition of fibroblasts from G 1 into the S phase (5,6). These two classes of cytokines have been termed competence and progression factors, respectively. One approach used to examine the release of cytokines from macrophages is the fibroblast proliferation assay in which quiescent fibroblasts are exposed to culture supematants from macrophages exposed to various stimuli. In most of these assays, the supernatant contains fetal calf serum (FCS), which provides the competence factor(s) necessary to facilitate the proliferation of fibroblasts (7-9). Recently, a fibroblast proliferation assay using platelet-poor .plasma [lacking competence factor(s)] as a substitute for FCS bas been described (I 0, 11 ). In this assay, the release of a competence-inducing PDGF-like growth factor from rat and human macrophages can be distinguished from other cytokines that act as progression factors."

Mar 1, 1992

By R. P. Adams, R. A. Beall

The Bureau of Mines developed a method to melt and cast specimens of hafnium- carbon alloy and studied their properties . A rotating - ladle vacuum or inert atmosphere arc furnace was designed , special electrodes and molds were developed , and operating procedures were worked out for casting small shapes . The cast specimens were evaluated according to their carbon content for melting point , density , microhardness , electrical resistivity , and oxidation resistance . Lattice dimensions were determined , and metallographic specimens were prepared . Photomicrographs were taken of specimens containing 2.72 , 5.50 , 6.47 , 9.97 , 12.8 , and 15.7 weight - percent carbon , and their grain structures were compared .

Jan 1, 1963

By Oliver Bowles

Granites are classed as igneous rocks ; they have been formed by the solidification of rock magmas or solutions from deep within the earth . It is an almost invariable law of nature that magmas which cool quickly form fine- grained or glassy rocks , while those that cool slowly are completely crystallized and are coarser- grained . Granites , being of the latter class , are regarded as having attained their solid form at considerable depth below the surface under conditions of high temperature and pressure . The constituent minerals crystallized out slowly , the crystals interlocking with one another . The great depth of overlying rocks that must have been present when crystallization took place has been removed by erosion over large areas on the surface of the earth , in consequence of which granites appear at or near the surface in many localities . The chief minerals of which granites are formed are feldspars , quartz , and either mica or hornblende . All the essential constituents except mica are as hard as , or harder than steel , therefore granites are difficult rocks to cut and dress . Granites are usually red , pink , or gray , depending on the color of the feldspars . If hornblende or black mica is abundant the rock may be dark green or almost black . Granites are characterized by massive homogeneous texture . They are classified as fine- grained , medium- grained , or coarse - grained . Medium- grained granites are those in which the feldspar crystals average about one- fourth inch in diameter . If relatively coarsegrained crystals appear in a fine -grained ground mass the rock is designated a porphyritic granite . Uniformity in texture and grain size are desirable in building and ornamental stone , although occasionally rocks of variable texture , such as the porphyritic granites , are used . A rock may have the mineral constituents of a granite but show a banded or platy structure due to recrystallization , folding , or other changes while the rock was in a plastic or semimolten condition . Such metamorphic rocks are called granite gneisses . They are used occasionally for building purposes but not as commonly as the uniformly textured granites . - Granites are named from the most abundant mineral other than quartz and feldspar that they contain , being called , for example , biotite granite or hornblende granite . - Commercially other igneous rocks granitoid in texture but more properly classified as syenites , diorites , or gabbros may be classed as granites . Thus the " black granite " of Little Falls , Minn . , is a diorite , and the " black granite " of Eastern Pennsylvania consists of diabase or gabbro . The question is sometimes raised as to the depth to which a granite occurrence may extend . In this respect granites differ notably from limestones , sandstones , or other sedimentary rocks . The sediments were originally laid down in relatively thin beds , and individual formations providing rock of economic value may be quite limited in thickness . Usually the usable beds range between 40 and 200 feet in thickness . On the other hand , granite comes up from below . Its depth is unknown , but in general is very great . It may even be measurable in miles . The reserves of material at depth are to be measured , therefore , by the economic depth of working rather than by the vertical extent of the rock mass . Exceptionally , granites of commercial quality may occur in sills or sheets of limited thickness flanked on either side by rocks of different character , as , for example , at Westerly , R. I.

May 1, 1930

1. In 2003, a total of 7,070 sand and gravel mining operations reported employment to the Mine Safety and Health Administration (MSHA). The largest percentage of all mining sectors was sand and gravel mines (49.1%). • Sand and gravel mines are found throughout all 50 states.

Feb 1, 2005

By Katherine Harding

Basic concepts of matrix algebra and manipulations of matrices are presented in such a way that little competence in mathematics is required. Examples are always included to illustrate concepts and techniques. The paper is divided into six sections. The first four sections are devoted to some of the more basic concepts of matrix algebra, whereas the last two sections are concerned with specific applications.

Jan 1, 1967

In 2004, a total of 4,401 stone mining operations reported employment to the Mine Safety and Health Administration (MSHA). Stone mines comprised 30.4% of all mining operations.

Sep 1, 2007

In 2007, a total of 14,871 mining operations reported employment data to the Mine Safety and Health Administration (MSHA).1 Almost half (48.4%) were sand and gravel mines, followed by stone mines (31.2%), coal mines (13.7%), nonmetal mines (4.9%), and metal mines (1.9%).

Aug 1, 2009

By V. Castranova, K. Van Dyke

"I. INTRODUCTIONA mechanism which is present in leukocytes and capable of releasing histamine from rabbit platelets was first described by Barbaro and Zvaitler in I966. A soluble mediator between rabbit leukocytes and platelets was also detected by Siraganian and Osier in 1971. This factor was isolated and characterized in 1971 by Benveniste et al. and named platelet activating factor i PAF). It was shown to be released from rabbit basophils through an antigen - IgE-dependent mechanism. The presence of PAF in human leukocytes' and its aggregation and releasing effects on human platelets were also demonstrated. Chemical analysis has shown that PAF is a glycerophospholipid with a choline polar head group. an ester-linked acyl chain at the second carbon and a nonester link at the first carbon.' The structure of the mediator was found to be 1-O-alky1-2-acetyl-sn-glyceryl-3-phosphoryl choline and it has been chemically synthesized.""' A variable portion exists in the alkyl group attached to the first carbon which can have a variety of molecular sizes such as C and C (where Cu is more abundant). Recent work by Pinckard et al."" has shown that there are at least five variations of the alkyl group.PAF has been shown to have a broad range of biological effects. Release of PAF from alveolar macrophages may be important in asthma, allergy, and shock states. In a rabbit model of antigen IgE anaphylaxsis. PAF can induce all of the effects of antigen challenge and. therefore is presumed to be a key mediator in production of anaphylaxsis. In addition to aggregating and degranulating platelets it is a potent chemoattractant."" and causes contraction of guinea pig ileum contraction of lung tissue and enhanced capillary permeability PAF has important effects in the kidney and is also known as the renal hypotensive factor proposed by Blank et al. who found the structure of PAF independently of Benveniste et al.' In producing these responses. PAF acts by a receptor-like mechanism. In platelets. PAF selectively desensitizes itself but not thrombin or collagen. In smooth muscle tissues a similar phenomenon occurs with anaphylatoxin or other stimuli.In vivo. PAF probably acts in concert with other agents in producing its various biological effects. It causes platelets to release histamine serotonin and RCS (rabbit-contractile substance formed from prostaglandins PPG2, PGH2 and TXA2) which contracts rabbit aorta. PAF can cause cells to release SRS-A and leukotriene B."

Jan 1, 1989

By W. E. Anable

The Bureau of Mines studied the purification of commercially available yttrium by melting it in a 100-kw electron-beam furnace. Button-scale melts were made to determine the ultimate purification that could be attained by melting yttrium at 1,733° to 1,770° C at low pressure (0.05 to 0.1 micron) for 1 to 120 minutes. In addition, numerous melts were made to study the effect of doping yttrium with carbon, 17 selected metallic additions, and 3 compounds. Except for nickel and zirconium, the metallic impurities in yttrium were lowered significantly on extended treatment; silicon was lowered only slightly. The nonmetallic impurities} oxygen, nitrogen, and carbon, were not lowered except on short exposures. In isolated instances, the oxygen content was lowered from 5,860 ppm to about 5,000 ppm. In most instances the carbon con-tent was lowered from 545 to about 220 ppm in 20 minutes and then increased again. It was concluded that yttrium cannot be purified by direct heating or by the doping technique employed.

Jan 1, 1965

By Earl T. Hayes, W. M. Sternberg, F. P. Williams

"INTRODUCTION The limited domestic demands for lithium salts and metal before the war were met readily by the use of minerals particularly lepidolite (lithium mica) and amblygonite (a lithium phosphate), from which lithium can be recovered relatively easily. New wartime uses, however, created such a demand that it became necessary to turn to spodumene (a lithium feldspar) as the principal source of supply. Although very large deposits of spodumene occur in South Dakota and in North Carolina, it much more difficult to extract lithium from spodumene than from lepidolite or amblygonite.During the spring and summer of 1942 a study was made in Salt Lake City laboratory of the Bureau of Mines on the recovery of lithium from spodumede. Preliminary tests were made on two processes - roasting with potassium sulfate 4/ 5/ and roasting with calcium chloride and calcium carbonate 6/ -,which appeared to be the most promising of the various processes that had been proposed. By roasting spodumene with approximately its own weight of potassium sulfate at 1,050º C. and leaching the product with water, about 70 percent of the lithium could be extracted. Consumption of the relatively expensive potassium sulfate, however, was high; much of the potassium was found in the insoluble leach residue, end large amounts were lost by volatilization and dusting. By roasting the spodumene with calcium chloride and calcium carbonate, nearly 90 percent of the lithium was chloridized temperatures of 850° to 1,050° C. Much of the lithium could be extracted from the calcine by leaching with water after roasting at the lower temperatures, but volatilization of lithium chloride was appreciable, amounting to 20 to 25 percent in a direct gas-fired furnace at temperatures of 800° to 850° C. At 1,000° to 1,050° C., volatilization was far from complete. Thus, it would be necessary to use both fume collection and leaching of the calcine, unless the roasting temperatures were sufficiently high to volatilize all the lithium chloride. Because of the well-known difficulties of collecting chloride fumes, it was decided to search for a better process."

Mar 1, 1946

"The main objective of this research is to identify the mechanisms of control of respirable dust generation in coal mines. Full understanding of the mechanics of crack propagation in coal is of fundamental importance in studies of the generation and control of respirable dust.The main objectives of this fracture investigation are: 1) to determine reliable data on the fracture toughness of coal as a parameter controlling unstable crack propagation; 2) to determine fracture propagation velocity in coal providing data on the terminal velocity at which crack bifurcation occurs and fine fragments of coal material are generated; and 3) to apply the critical strain energy density criterion to model mixed mode crack propagation in coal.The development of the protocol, laboratory procedure and equipment necessary to conduct an extensive mixed mode fracture toughness testing program has been completed. About 80 mixed mode fracture toughness tests, 10 good fracture velocity records and over 50 fracture surface examination with the SME are available. The details of the mixed mode fracture toughness testing are available in a paper titled, ""Development of Mixed Mode Testing System for Geologic Materials"" which is available from the center. The average fracture toughness and critical strain energy density values for the three seams investigated to date are included in the attached Figures 71, 72, 73."

Nov 1, 1988