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By J. J. Cummins

Green River oil shale previously extracted by benzene was heated at 150°, 200°, 250°, 300°, and 350° C for 0.5 to 360 days to determine the rate at which kerogen degrades to thermal products, the types of thermal products formed, and the effect of prolonged low-temperature heating (preheating) upon subsequent assay yields. Thermal decomposition of kerogen at 150° to 350° C is treated as a first-order reaction. The specific reaction rate for kerogen decomposition increases from 2.2 X 10-4 per day at 150° C to 2.0 X 10-1 per day at 350° C. The calculated kerogen activation energy is 19 kcal. Variations in the rate of formation of individual type components of the pyrolytic products were found. Carbon balances show an increase in the amount of kerogen converted to bitumen and oil (from assay of preheated oil shale) as the temperature of preheating increased from 150° to 350° C. Total product from shale preheated at temperatures of 150° and 200° C gave less than 100 percent of Fischer assay yields while the total products from shale preheated at temperatures of 250° to 350° C gave greater than 100 percent of Fischer assay yields.

Jan 1, 1972

By R. C. Gabler

Laboratory tests on a combined nitrogen roast--two-stage leach--electro-winning approach show promise as a possible process for recovering copper, sulfur, iron oxide, and valuable minor metals (gold, silver, and molybdenum) with a minimum impact on the environment. During the nitrogen roast at 800° C, 15 to 20 percent of the sulfur together with a significant fraction of the volatile elements, such as arsenic, bismuth, lead, and zinc, are removed from the chalcopyrite concentrate. The resulting calcine, consisting of 8-chalcopyrite, troilite, and a bornitelike structure, is leached with hydro-chloric acid to remove 70 to 85 percent of the iron. The digenite in the leach residue is dissolved in an oxygen-saturated, spent sulfate electrolyte. Using a graphite 'anode plus sulfur dioxide to reduce interference from ferric iron, copper of 99.99+ purity is electrowon at current efficiencies of 88 to 92 percent and a cell voltage of 0.4 to 0.5 volt. Copper recovery for the overall process is 98 to 99 percent. Sulfur is obtained in the elemental form from the roasting and leaching steps. Iron can be recovered from the hydro-chloric acid leach solution. Gold, silver, and molybdenum are concentrated in the silica residue from the spent electrolyte leach.

Jan 1, 1975

By V. Castranova, K. VanDyke

"INTRODUCTION A soluble mediator has been described which is released from activated rabbit leukocytes and induces histamine secretion from rabbit platelets (Barbaro and Zvaifler, 1966; Siraganian and Osler, 1971). This factor has been isolated, characterized and named platelet activating factor, PAF (Bcnveniste et. al., 1972). PAF has since been chemically identified as l-0-alkyl-2-acetyl-sn-glyceryl-3-phosphocholine (Benveniste et. al., 1979; Demopoulous et. al., 1979).PAF is a lipid mediator of broad biological activity. It causes smooth muscle contraction, contraction of lung tissue and decreased FEV 1; while enhancing capillary permeability thus causing edema (Pinkard, 1983). In addition, PAF is a chemoattractant and can lead to inflammation.PAF has been reported to stimulate the release of lysosomal enzymes, leukotriene B,, and lipid metabolites from neutrophils (Smith et. al., 1983; Shaw et. al., 1981; Lin et. al., 1982; O'Flaherty et. al., 1984). The objective of the present investigation was to further characterize PAP-induced stimulation of granulocytes and to develop a bioassay, i.e. chemiluminescence, for screening PAF receptor antagonists and inhibitors of PAP-induced activation of granulocytes. The possible use of the chemiluminescence assay to monitor PAF synthesis by human granulocytes is also described.METHODSBlood was drawn from healthy volunteers into a blood storage bag containing CPD anticoagulant. Granulocytes were partially purified by dextran sedimentation and further purified by centrifugal elutriation as described previously (Jones et. al., 1980). Granulocytes obtained by this procedure were approximately 95 percent pure. The number of granulocytes in this preparation was determined using an electronic cell counter (Coulter Model Z1, Coulter Instrument Co., Hialeah, FL). Isolated granulocytes were used to monitor membrane potential, hydrogen peroxide and superoxide release, oxygen consumption, calcium uptake and, in some cases, chemiluminescence. Studies of PAF receptor antagonists were conducted using neutrophils isolated by density centrifugation. Briefly, blood was layered onto Mono-Poly-Resolving Medium (Flow Laboratories, McLean, VA) and centrifuged at 22 °C and 300 g for 30 min. Neutrophils collected from the second band of this gradient were at least 90 percent pure."

Jan 1, 1989

By Scott Turner

To be successful , human exertion employed for the creation of value requires power and heat ; the ability to produce concentrated power in great quantities has resulted in the relatively recent industrial development that is so profoundly affecting the world . In our commercial history , we have advanced through several stages in the selection of the most suitable fuels , continuously striving to increase the flexibility and range of energy- transmission . The easy distribution of light , power and heat is the leading factor in the decentralization of industry which promises to correct some of the serious evils that have followed in the footsteps of our commercial development . The distribution of fuel in quantity in so convenient a form and with such an attractive reliability- factor as can be had with gas , meets the modern conception of efficient service . Natural gas has been used in this country for more than a century, but recently it has attained a prominence far in excess of anything known in its earlier history. We may consider that we are now getting into our real stride in the utilization of our natural- gas resources . : In a country like the United States , wherein we are accustomed to mammoth achievements , we may be inclined to accept casually the noteworthy technical and economic advances which have resulted in the expansion of natural- gas distribution . About three years ago , the transmission of natural gas a distance of more than 250 miles from its source was first accomplished , and this was really a noteworthy engineering feat . Today , this useful commodity is being transported twice that distance , and lines are being laid which will carry gas more than 900 miles from the points of occurrence . Let us not take such outstanding improvements too much as a matter of course ; the industry should be congratulated on its long steps forward .

Oct 1, 1930

By R. V. Ramani, R. Stefanko, G. W. Luxbacher

Le Système International d'Unités (SI) Equivalents of Common United States Units Length 1 ft (foot) = 0.30480 m Mass 1 lbm (pound mass) = 0.45359 kg Force 1 lb (pound) = 4.4482 N Volume Flow Rate 1 cfm = 0.00047195 m3/s Mass Flow Rate 1 lbm/min = 0.00756 kg/s Pressure (wg at 20° C) 1 inch wg (water gage) = 248.36 N/m2 1 inch wg = 248.36 Pa Power 1 hp (horsepower) = 0.74570 kW Energy 1 ft-lb = 1.3558 J Torque 1 lb-inch = 0.11298 N-m

Jan 1, 1977

By Maria I. De Rosa

Table 1 and figure 1 show the number of fires and fire injuries that occurred in underground metal/nonmetal and stone mines by state during 1990-2001. Table 1 also shows the injury risk rates, employees' working hours, and lost workdays. Overall, 65 fires occurred in 20 states; these include 2 fires and no injuries for contractors. Six of the fires caused nine injuries. The yearly average was 5.4 fires and 0.75 injury. Forty-one fires with 2 injuries occurred in metal mines, 14 fires with 7 injuries occurred in nonmetal mines, and 10 fires with no injuries occurred in stone mines. The underground mine fires required 25 mine rescue team interventions and 30 mine/section evacuations. The Ewhr value was 260 x 10° hr (Irr = 0.007), and the LWD value was 83. Idaho had the most fires (eight fires and no injuries), followed by Louisiana (seven fires and two injuries), Michigan (six fires and six injuries), and Missouri (six fires and no injuries). Of these states, Michigan had the highest injury risk rate value (Irr = 0.146). Table 2, partly illustrated in figure 2, shows the number of fires, fire injuries, risk rates, employees' working hours, and lost workdays by time period. The number of fires during the six time periods show an increase during the fourth period followed by a sharp decrease during the fifth period and a sharp increase in the last period. The number of fire injuries show an increase followed by a decrease during most of the periods, accompanied by a decline in employees' working hours during most of the periods; an increase is seen during the third and fourth periods. The In values follow patterns similar to those shown by the injury values. Tables 3-8 show the number of fires by ignition source, method of detection and suppression, equipment involved, location, and burning material by time period. Figure 3 shows the major variables related to fires for 1990-2001. Table 9 shows the number of fire injuries per number of fires causing injuries and total fires by year, ignition source, equipment involved, and location.

Jan 1, 2004

Reduce dust exposure of longwall shearer operators by keeping them upwind of the primary cutting drum. Approach Use a different coal cutting sequence by cutting from headgate-to-tailgate, making the cleanup pass from tail-gate-to-headgate. How It Works The cutting action of the shearer drum is usually the primary source of respirable dust at longwall shearer faces. Dust exposure of the shearer operator is deter-mined by his position relative to the lead drum, which is normally in the raised position taking a full sump. On long-wall faces where the cut pass is taken from tail-to-head, against the primary airflow, the shearer operators must remain at their controls, on the return-air-side of the primary dust source, to maintain proper control. A simple method to lower shearer operators' dust exposures is to extract the primary coal from head-to-tail, thus positioning the operators up-wind of the lead cutting drum. The bottom coal is then cut, and the floor cleaned by the trailing drum during the tail-to-head cleanup pass. This sequence places the primary dust source, the cutting action of the shearer drums, on the return-air side of both shearer operators, except when cutting out at the longwall headgate.

Jan 1, 1984

By Ray J. Holmquist

"INTRODUCTION The Elk Mountain mica deposit was examined in June 1943 by the Bureau of Mines. An exploratory project and an access road for the property were recommended, provided the zinc was put in operation under competent management. K. Garard obtained a lease on the properly and started operations in June 1944; this was followed immediately by the Bureau's exploratory work. Road construction was begun by the Forest Service in July the same year.The lessee mined mica from the richest exposure with a crew of three men for 2-1/2 months. His operation terminated late in September, but the Bureau of Mines project and the Forest Service road construction continued until snow forced suspension of activity during the first week of November.The Bureau of Mines work consisted of trenching with a bulldozer, hand excavating on undeveloped outcrops, extending an existing adit, and starting a new adit below the older workings."

Jul 1, 1946

By Doris M. Hyde

Belize remained relatively insulated from the social and political turmoil that affected some of its Central American neighbors. This stability encouraged new foreign investments that assisted the economy, especially in tourism and agriculture. The mineral sector remained limited to construction-oriented materials. Oil exploration efforts continued by the various concessionaires.

Jan 1, 1987

By J. J. Rutledge, C. A. Herbert

In 1916 the Bureau of Mines, the Illinois Geological Survey, and the University of Illinois, working under a cooperative agreement, began an investigation of the subsidence of the surface above coal- mining operations. Four widely separated places where mining was in progress were selected as observation stations-one in the northern Illinois longwall coal field, one in the central Illinois coal field where the room-and- pillar panel system of mining was being used, and two in the thick coal of southern Illinois where the room-and-pillar panel system of mining was employed. These four points of mining activity gave a rather wide opportunity for observing subsidence when different mining methods were used. The four places selected for investigation of surface subsidence due to coal mining have been designated as follows: 1. A, in the northern Illinois longwall coal field, where the coal company has been operating coal mines for 30 years and where long- wall advancing is the only method of mining. 2. B, in Perry County, where panel room-and-pillar mining of a thick seam of coal is in progress and where mining operations have been carried on about 40 years. 3. C, in Macoupin County, where the coal company has been min- ing coal by the panel room-and-pillar method for about 15 years. 4. D, in Franklin County, where the coal company has been mining coal for 10 years by the panel room-and-pillar method.

Jan 1, 1927

By Jonisha P. Pollard

In restricted vertical working heights such as low-seam coal mines, workers are forced to assume kneeling or squatting postures to perform work. These postures are associated with increased risks for the development of significant knee pathologies such as meniscal tears and osteoarthritis [1,2]. Previous research has shown an increased applied knee flexion moment when kneeling in high flexion [3]. However, these models have been applied to flexion up to 140° which neglects contact between the thigh and calf which occurs beyond 140°. In addition to thigh-calf contact, when kneeling near full flexion there may be additional contact between the heel and gluteal muscles. To the author?s knowledge, heel-gluteus contact has not been previously investigated, but thigh-calf contact has received some attention. Zelle (2007) reported thigh-calf contact forces up to 30% bodyweight (BW) [4]. Zelle (2009) reported decreased knee forces when accounting for thigh-calf contact [5]. Caruntu (2003) reported erroneous force and moment estimations when thigh-calf contact was neglected from models to determine muscle and ligament forces [6]. In this study thigh-calf and heel-gluteus contact forces were quantified to determine their effect on the externally applied flexion moment in high flexion.

Jan 1, 2009

By Scott Turner

The settlers of a new country necessarily suffer at first from the lack of accumulated stocks of metals - in-use that are possessed in older countries . Our American colonists were at first compelled to import their metals in manufactured forms , and it must have proved difficult to produce an exportable surplus of commodities with which to pay for them . These circumstances stimulated a search for domestic ore deposits . Various discoveries resulted , so that as early as 1628 , we find the colonists importing two craftsmen from England to establish iron -works in Massachusetts to beneficiate local ores . In 1648 , an iron -works at Lynn was producing metal at an annual rate of 400 tons . Later on , the colonial iron industries became of importance , some metal being actually exported to England . The people of this country thus early became convinced of the necessity for domestic mineral production . It is now little realized how persistent were their efforts to - make mineral discoveries , before the gold- rush to California ; the extraordinary success of our subsequent mineral explorations has overshadowed the earlier record . Precise and complete accounting of our mineral production , having the character of national bookkeeping , is available only for the series of years beginning with 1880 , when commences the official record that is provided by the Government publication called Mineral Resources of the United States . In the period of 52 years , from 1880 through 1932 , the value of mineral production of the United States amounted to more than 122 billion dollars . Only 12 billions of this total were produced in the 21 years , 1880-1900 , while nearly 110 billions were produced in the first 31 years of the present century . Of this 110 billions , over 53 billions were produced in the most recent decade , 1921- 1930 , the production of the previous decade , 1911-1920 , having been only 37 billions , though it included the war period ; that of the decade 1901-1910 was 16 billions . In 1931 , the total value of mineral products of the United States was $ 3,180,000,000 , compared with an average annual value of $ 5,556,000,000 during the previous five - year period , 1926-1930 . The decline in 1931 from that average was therefore 43 per cent . As to the three great groups of mineral commodities , metals fared worst , with a decline of 55 per cent in the value of their production , while the value of fuels declined 39 per cent , as did that of the nonmetals group .

Jan 1, 1933

By Albert E. Long

By the USB of X-ray diffraction methods, scientists have learned how the atoms in a diamond crystal are arranged and how the atoms are tied together by chemical bonds. They have found that, even though the bonds between all atoms of the diamond have equal strength, they are so distributed that there are more bonds in certain layers or directions through the crystals than in others. The unequal distribution of the bonds in certain directions creates planes, within the diamond, of unequal strength and resistance to abrasion. The location and disposition of the directions that are relatively harder than the others were determined by Slawson and Kohn 3/ in 1950. By plotting these directions on stereographic projections they delineated the hard regions on the surface of the diamond, but only those trained in the methods of crystallography can readily interpret their diagrams. The principal purpose of this report is to present information that will help individuals without previous training in crystallography to learn to recognize the special features of the surfaces of diamond crystals that are definite guides to the location of the various hard directions of the stones. A crystallographer trained in using various precise laboratory instruments might consider such rudimentary criteria as rather unscientific, but these simple characteristics of diamond crystals are practical clues which anyone equipped with a magnifying lens can find and recognize. The use of the special faces, points, edges, and growth lines as a gui.de in orienting a diamond will allow it to be placed in a position reasonably close to the optimum. Preliminary results of experimental work conducted by the Bureau of Mines indicate that this is all that is necessary in setting diamond-bit crowns. This experimental work demonstrated that setting bits with the hard vectors of the diamond as cutting points greatly reduces the diamond loss and increases the efficiency of the bit.

Jan 1, 1952

By R. V. Ramani, R. Stefanko, G. W. Luxbacher

1 11 THIS IS A DIGITAL COMPUTER SIMULATION OF THE VENTILATION SYSTEM OF A MINE LOCATED IN WASHINGTON COUNTY, PENNSYLVANIA. THE VENTILATION SURVEY ON WHICH THIS SIMULATION IS BASED WAS RUN FROM OCT. 27-30 AND ON NOV. 2, 1976 IN THE ACTIVE PORTION OF THE MINE INBY COMBS SHAFT AND THE INACTIVE PORTION AFCUND AND INBY DONAHOO SHAFT. FOLLOW-UP SURVEYS WERE THEN RUN ON FEB. 18 AND FROM MARCH 7-11, 1977 TO INCLUDE THE MAIN HAULAGE SYSTEM OUTBY THE ACTIVE AREAS OF THE MINE. ALL SURVEY DATA WAS NORMALIZED TO A STANDARD DENSITY OF 0.075 POUNDS/CU.FT. PRIOR TO THE CALCULATION OF INPUT PARAMETERS FOR THIS SIMULATION. IN THIS RUN, THE ORIGINAL VENTILATION NETWORK HAS BEEN MODIFIED TO INCLUDE NEW INTAKE AND RETURN AIRSHAFTS AT THE WEST MAINS.

Jan 1, 1977

By Paul W. Johnson

An evaluation is made of a lime-soda sinter process for extracting alumina from anorthosite. In this process, alumina is extracted by sintering anorthosite with soda ash and limestone, and then leaching the sinter with a dilute sodium carbonate solution. The sodium aluminate solution formed during leaching is separated from the residue and treated with lime in autoclaves to remove dissolved silica before alumina trihydrate is precipitated with carbon dioxide. The trihydrate is then calcined to a-alumina. Two options, dry grinding and wet grinding, are used in the sintering step. For plants producing 1,000 tons of alumina per day for the dry grinding and wet grinding options respectively, the estimated operating costs are $75.40 and $74.36 per ton of alumina when charging $2.50 per ton for anorthosite and $1.00 per ton for limestone. The fixed capital costs based on a Marshall and Stevens chemical equipment index of 240.0 are $76 million and $70 million respectively. This process, when treating anorthosite, using either option, is not competitive under current economic conditions with the Bayer process treating bauxite to produce alumina.

Jan 1, 1968

By Steven J. Page

The increasing concern for dust control in metal and nonmetal mining prompted the Bureau of Mines to investigate the dust suppression technique of applying foam to face drilling and crushing operations in a gypsum mine. Previous attempts to achieve effective dust control on face drills using other techniques, such as dry collection and boom-mounted external water sprays, have not been successful. The largest problem encountered when using these techniques has been the lack of sustained effective dust capture at the face. Results for two faces studied show that injection of the foam through the drill steel provided an average dust reduction of 95 pct. However, the use of foam on the crusher provided no dust reduction at the operator's position (because of good local ventilation) and a 27-pct average dust reduction for two feeders at a location midway between the operator's position and the crusher. The conclusions obtained from this study are that (1) foam can be an extremely effective dust control technique when used on localized dust sources such as dust generated within a blasthole during drilling, and (2) foam is only marginally effective as a dust control technique when used on nonlocalized dust sources such as dust generated during the feeder-and-crusher operation.

Jan 1, 1981

By A. Visnapuu

High-grade synthetic rutile has been produced in the laboratory from domestic ilmenite concentrates by a new carbonyl process. The ilmenite was first reduced to convert the iron oxides to metal and then treated at temper-atures over 1000 C in high-pressure carbon monoxide (CO) to convert the iron to the pentacarbonyl. Rapid carbonylation was achieved in the presence of small quantities of selected promoters. Maximum iron removal occurred at temperatures between 110° and 130° C at CO pressures from 1,000 to 1,400 psig. Iron pentacarbonyl appeared as liquid and vapor in the reactor and could be removed by gravity flow and vapor transport. More than 90 pct of the iron was extracted in 2-hr experiments at pressures of 1,000 psig and above. The Ti02 product is porous owing to the removal of the iron, has the rutile crystal structure, and is suitable for chlorination. Waste disposal problems associated with the process would be minimal because the iron pentacarbonyl can be decomposed to produce iron powder or pellets for sale and CO for recycling.

Jan 1, 1973

By T. W. Beck

The National Institute for Occupational Safety and Health (NIOSH) conducratory and field tests to evaluate the effectiveness of dust collector bags for reducing dust liberation and operator exposure from a roof bolter’s dust collection system. The laboratory tests evaluated the bag’s effectiveness to contain dust and the effect on canister filter loading in both a bag and bagless condition. The dust emissions from the collector’s exhaust were also measured in each condition during laboratory testing and show that nearly 100% of the test dust fed into the collector was captured by the dust bags. Loading and pressure drop on the dust collector’s canister filter is greatly decreased when using the bags, enabling longer periods of drilling without filter removal/cleaning. The field results showed that, even though dust standards were met, respirable dust in exhausted emissions was reduced around the bolter. Laboratory and field results show that benefits from use of the bags are realized in all areas of operator exposure.

By W. P. Yant

The hazard to health from contamination of air by a noxious gas depends not only on the potential harmful response attending exposure., but also on the warning properties, which in effect may be termed the "accompanying warning response," This warning may be manifested as an odor, taste, irritation of the eyes, nose, or throat, or perhaps headache, vertigo,, or nausea. These manifestations may be painful and even slightly harmful, but to a much lesser degree than the primary injury of exposure. The warning response mitigates hazards directly in proportion to the degree of intolerability which -accompanies injurious exposure, and accordingly its absence augments hazards. This accounts for the fact that the actual health hazards from a nonodorous or non-irritating gas or vapor of comparatively low toxicity sometimes equal or exceed the hazard from a considerably more toxic substance, but one which possesses a marked odor or produces eye, nose, or throat irritation in advance of harmful exposure. When a substance lacks the properties for giving warning, it is often possible to impart them by the addition of a small amount of another substance which has an exceedingly high warning intensity. The vapors of this substance, commonly termed a "warning agent" or "tracer gas," escape and mingle with the gas or vapor which lacks warning properties and thereby apprises persons of the latter's presence. The amount of the warning agent added is that which will give adequate warning in advance of serious physiological harm from the dangerous gas or vapor.

Jan 1, 1930

By J. Feldman

This report contains a description of the distillation laboratory at Bruceton, Pa., which was established to aid in the separation and identification of the products produced in the synthetic liquid fuel processes under study there. Compounds present in synthetic liquid fuels may include aliphatic from C1 to C60 or greater. Alcohols, ketones, esters, aliphatic carboxylic acids, saturated hydrocarbons, olefins, and diolefins are all found in Fischer-Tropsch products. Coal-hydrogenation products contain, in addition to aliphatic compounds, a large proportion of naphthenic material and aromatic compounds ranging from benzene to coronene; in addition, appreciable quantities of tar bases and tar acids are present. In designing the laboratory, therefore, provision had to be wade for the greatest amount of flexibility and versatility. A great deal of standardization of basic equipment had also to be designed to permit interchange of parts and services.

Jan 1, 1951