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By J. E. Urosek, K. L. Cashdollar, D. A. Beiter, G. J. Shemon

The National Institute for Occupational Safety and Health (NIOSH) and the Mine Safety and Health Administration (MSHA) conducted joint research to evaluate explosion blast effects on mine ventilation stoppings at the NIOSH Lake Lynn Experimental Mine (LLEM). After mine explosion accidents, MSHA conducts investigations to determine the cause(s) as a means to mitigate or eliminate future occurrences. As part of these post-explosion investigations, the condition of underground stoppings, including the debris from damaged stoppings, are documented as evidence of the strength and the direction of the explosion forces. The LLEM data showed that a total pressure of 52 kPa (7.6 psi) destroyed the solid concrete block stopping, ~36 kPa (~5.2 psi) destroyed the hollow-core concrete block stopping, and 9 kPa (1.3 psi) destroyed the steel panel stopping. These results will assist investigators in determining the explosion forces that destroy or damage stoppings during actual coal mine explosions.

By Lowell Stroud

A windowed-cell phase equilibrium apparatus was used to obtain equilibrium vapor- liquid data for a helium-bearing natural gas (Hogback) at temperatures from -100 to -250° F and pressures to 500 psia. Anomalous phase behavior resulting in the formation of two stable liquid phases occurred at tmperatures below -200° F and pressures above 200 psia. A review of the published literature on the occurrence of multiple-liquid phases included in the report indicates that the experimental results with Hogback gas are the first substantiated evidence of a vapor-liquid-liquid equilibria in a helium-containing natural gas.

Jan 1, 1963

By Elizabeth A. Johnson

Minor-element behavior and interaction in the copper matte-iron silicate slag system have been studied by the Bureau of Mines. In the present work, the possibility of interactions among the minor elements As, Sb, Bi, Se, and Te was investigated. Equilibrations of matte, slag, and one of each of the five minor elements were performed at 1,250° C under typical matte smelting atmospheres of CO, CO2, and S02 for mattes containing 40, 50, and 60 pct Cu. Results are compared with those of a previous Bureau of Mines study in which all five minor elements were present simultaneously.

Jan 1, 1984

By Arthur B. Johnson

The Bureau of Mines investigated the concentration characteristics of high-clay sylvinite ores from four potash companies operating in the Permian Basin near Carlsbad, N. Mex. These ores, containing 13 to 22 percent K20 and 3 to 7 percent clay slimes, cannot be effectively processed by current commercial flotation methods because of their high slime content. A solution to this problem was shown to be the use of two-stage moderate scrubbing conditions and washing of the ore as opposed to strenuous attritioning. Bench-scale physical beneficiation techniques for recovering potash minerals and the development of ore-dressing systems by flotation resulted in obtaining acceptable product grades and recoveries. By using a coarse grind, emphasis was placed on production of premium granular and coarse products. Flotation results showed that concentrates of 58.7 to 60.4 percent K20 with recoveries of 71.0 to 83.4 percent 0f the K20 values can be obtained.

Jan 1, 1971

By Seth C. Schaefer

The Bureau of Mines studied thermodynamic properties of Al-Ni alloys con¬taining 0.54 to 30.04 atomic percent nickel with the aid of the high-temperature galvanic cell Al(1) // Al+3 (AlCl3 in NaCI.KC1) // Al-Ni alloy (1 or s). Activities of aluminum and nickel (compared with pure liquid metals as the standard state) show pronounced negative deviation from Raoult's law at 1,273 K. The properties [?G, ?Gxs, ?G ideal, ?GA1, AGxs1, ?Gni , and ?GNixs] have been derived from the experimental data and are summarized in tables and illustrations. At 1,127 K, the thermodynamic stability for the invariant three-phase equilibrium consisting of a saturated liquid, A13Ni, and A13Ni2 has been uniquely defined by an activity for aluminum of 0.751. A free energy of formation at 1,127 K of -7,940 cal/g-atom was derived for the compound A13Ni.

Jan 1, 1975

By L. B. Pankratz

High-temperature heat-content values of gallium and scandium sesquioxides were measured over the temperature range from 298° to 1,800° K. The results fill gaps in the thermodynamic information for these compounds; no previous similar data existed. The heat-content values were combined with heats and entropies of formation to obtain free energies of formation of gallium and scandium sesquioxides to 2,000° K. The thermodynamic stabilities of the sesquioxides of aluminum, gallium, scandim, and yttrium were compared.

Jan 1, 1963

By R. P. Beyer

Low-temperature heat capacities and standard enthalpy of formation of copper difluoride (CuF2) were determined by the Bureau of Mines. The low-temperature heat capacities were determined from 11 to 302 K by adiabatic calorimetry. The enthalpy of formation was determined by HC1 solution calorimetry. The standard values of entropy (S°) and enthalpy of formation (?Hf°) at 298.15 K are l8.65±0.03 cal/deg mole and -129.02±0.29 kcal/mole, respectively.

Jan 1, 1978

By J. M. Stuve

The standard heats of formation (?Hf°) of holmium trichloride and terbium trichloride were measured by solution calorimetry. Heats of solution of holmium and terbium metals and their anhydrous chlorides were measured in 4.360 molal HCI at 298.15° K. From these measurements ?Hf° for HoC13 (c) was calculated as -240,290 ±1,700 cal/mo1e, and ?Hf° for TbC13 (c) was calculated as -238,330 ±1,500 cal/mole at 298.15° K.

Jan 1, 1967

By W. W. Weller

Heat capacity measurements of anhydrous cobalt sulfate (CoSO4), copper sulfate (CuSO4), nickel sulfate (NiSO4), and zinc sulfate (ZnSO4) were conducted over the temperature range 51° to 298° K. The results were used to evaluate the following entropies at 298.15° K (cal/deg mole): CoSO4, 28.1; CuSO4, 26.8; NiSO4, 24.8; and ZnSO4, 26.4. Entropies were combined with heats of formation to give free energies of formation.

Jan 1, 1965

By R. Barany

The heats of formation of seven substances were determined by solution calorimetry. At 298.15° K, the heat of formation of lithium sulfate from lithium, rhombic sulfur, and oxygen was -343.1 ± 0.7 kcal/mole, and the heat of formation of lithium sulfate monohydrate from lithium, rhombic sulfur, oxy-gen, and hydrogen was -414.3 ± 0.7 kcal/mo1e. For the silicates, the heats of formation at 298.15° K from the elements were kaliophilite, -503.8 ± 0.5 kcal/mole; leucite, -721.6 ± 0,8 kcal/mole; eucryptite, -505,2 ± 0.6 kcal/mole; alpha-spodumene, -727.9 ± 0.9 kcal/mole; and beta-spodumene, -721.1 ± 0.9 kcal/mole. The corresponding heats of formation at 298.15° K from the constituent oxides were kaliophilite, -42.7 ± 1.1 kca1/mole; leucite, -42.8 ± 1.1 kcal/mole; eucryptite, -16.1 ± 0.7 kcal/mole; alpha-spodumene, -21.0 ± 0.7 kcal/mo1e; and beta-spodumene, -14.3 ± 0.7 kcal/mo1e.

Jan 1, 1966

By John W. Walkiewicz

The U.S. Bureau of Mines has conducted studies to utilize rapid microwave heating to stress fracture ore samples. Iron ores containing hematite, magnetite, and goethite were subjected to microwave energy in batch operations at 3 kW and heated to average maximum temperatures between 840 and 940 °C. Standard Bond grindability tests showed that microwave heating reduced the work index of iron ores by 10 to 24 pct. In a microwave chamber designed to simulate a continuous throughput operation at 3 kW, the grindability of a taconite ore was improved by 13 pct at a bulk temperature of 197 °C. Because stress cracking occurred at a lower temperature, less energy was consumed. To further improve the economics of microwave fracturing, higher powers up to 16 kW were used to rapidly heat samples to relatively low temperatures in a continuous, belt-fed applicator. A significant improvement of grindability was obtained with a larger rod mill feed size in comparison to a minus 6-mesh Bond feed.

Jan 1, 2010

By R. Barany

The heats of formation of anhydrous ferric sulfate and anhydrous indium sulfate were determined by solution calorimetry. At 298.15° K the heats of formation from the metal, rhombic sulfur, and oxygen were -615.6 ±O.7 kcal/mole for ferric sulfate and -649.6 ±O.6 kcal/mole for indium sulfate. Heats of decomposition at 298.15° K are given for the reaction that forms metal oxide, sulfur dioxide, and oxygen) and for the reaction that forms the metal oxide and sulfur trioxide.

Jan 1, 1965

By J. M. Stuve

Calorimetric determinations of the low-temperature heat capacities, standard enthalpy of formation, and high-temperature enthalpies were made of (Na20)4 ?Fe20,(c). The resulting values of entropy (S°), enthalpy of formation (?Hf°), and free energy of formation (?Gf°) at 298.15° K are 104.676 cal/deg mole, -656.2 ±.kcal/mole, and -603.4 A kcal/mole, respectively. Tabulations of Cp°, S°, - (G°-H°298)/T, H°-H°298, ?Hf°, ?Gf°, and log Kf are given to 1,200° K.

Jan 1, 1971

By Frank B. Fulkerson

Three of the five primary aluminum producers in the Pacific Northwest have facilities in the region to make aluminum mill products. Only one of the three, however, produces a variety of shapes and forms. The principal reason for the lag in development of an aluminum mill products industry was found to be transportation cost. The long range outlook is for expansion, based mainly on growth of the western market for aluminum used in construction, containers and packaging, electrical applications, diesel trucks, mobile homes, and irregation pipe. Consumption of western aluminum mill products in 1985 is projected at 1.1 million tons, compared with estimated consumption of 250,000 tons in 1961.

Jan 1, 1965

By Frank B. Fulkerson

Three of the five primary aluminum producers in the Pacific Northwest have facilities in the region to make aluminum mill products. Only one of the three, however, produces a variety of shapes and forms. The principal reason for the lag in development of an aluminum mill products industry was found to be transportation cost. The long range outlook is for expansion, based mainly on growth of the western market for aluminum used in construction, containers and packaging, electrical applications, diesel trucks, mobile homes, and irregation pipe. Consumption of western aluminum mill products in 1985 is projected at 1.1 million tons, compared with estimated consumption of 250,000 tons in 1961.

Jan 1, 1965

By R. Barany

The heats of the glass-crystal transformation of nepheline (Na0.7794K0.2206AlSiO4) and wollastonite (CaSiO3) and the heat of formation of nepheline at 298.15° K were determined by solution calorimetry. For the glass-crystal transformations, the heat values were -9.0 ± 0.3 kcal/mole for nepheline and -8.1 ± 0.2 kcal/mole for wollastonite. The heat of formation of nepheline was -34.8 ± 0.6 kcal/mole from the oxides and -501.0 ± 0.5 kcal/mole from the elements.

Jan 1, 1966

By T. A. Sullivan

High-purity vanadium metal was prepared by electrorefining commercial vanadium in a molten sodium bromide, potassium bromide, and vanadium dibromide electrolyte. Variables investigated were operating temperature, current densities, electrolyte composition, and condition of the anode. The purity of the refined metal was in the range of 99.95 percent vana-dium. Iron and oxygen in the 50- to 250-ppm range were the only major impurities. Metal with hardness numbers of 50 to 60 in the Rockwell F scale was prepared from feed material with a Rockwell B hardness of 90. The arc-melted metal was highly ductile and could be cold-worked into sheet or foil.

Jan 1, 1965

By W. W. Weller

Low-temperature heat capacities of scandium sesquioxide (Sc203) and a mixture of cerium sesquioxide (Ce203) and cerium dioxide (CeO2) were measured over the temperature range from 50° to 298° K. The entropy of scandium sesquioxide at 298.15° K was evaluated directly as S°298.15 = 18.4 ± 0.1 cal/deg mole. That of cerium sesquioxide was extracted by combining the heat-capacity data for the mixture with those for pure cerium dioxide; the result was S298.15 36.0 ± 1.0 cal/deg mole.

Jan 1, 1963

By S. M. Runke

An ever-increasing demand for beryllium and beryllium alloys has directed attention to the milling of low-grade domestic deposits as a possible means of supplying part of the Nation's ore requirements. The United States generally produces less than 10 percent of its annual supply. For example, new supply in 1953 was estimated at about 9,250 tons, of which the United States imported 8,500 tons. Domestic production was only 750 tons.2/ Since record high prices for beryl in 1952 and 1953 did not greatly increase domestic product ion, the United States must develop mechanical beneficiation processes to use low-grade deposits and reduce dependence on foreign sources

Jan 1, 1954

By Alton B. Cook

Data are presented to show oil vaporization resulting from the passage of natural gas through a sand-packed tube saturated with synthetic reservoir oils. The Bureau of Mines performed 13 experiments, using reservoir oils synthesized with base crude oils of approximately 22°, 35°, and 45° API, at 100°, 175°, or 250° F and 1,100, 2,600, or 4,100 psia. It has been determined that the amount of vaporization is significant if proper conditions exist. These experiments show that oil vaporization depends on pressure, temperature, volatility of the oil, and amount of gas cycled. Increases in each of these conditions increase the volume of oil vaporized.

Jan 1, 1969