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By Robert H. Dickson

This paper describing the mining practices at the Verde Central mine at Jerome, Ariz., is one of a series being prepared by the United States Bureau of Mines on mining practices, methods and costs in various mining districts of the United States. ACKNOWLEDMENTS The costs contained in this paper were prepared by R. J, Huddleston, chief clerk, Verde Central Mines, Inc.

Jan 1, 1931

By J. Hudy

The performance of six dense-medium washers was evaluated in five preparation plants. Three of the plants were making a two-product separation that produced a clean coal and a refuse; one plant employed dense-medium vessels in series to effect a primary and a secondary separation; and one plant was equipped with a two-compartment washer effecting two separations in one vessel. The separate secondary drum-type washer produced a low-ash metallurgical coal and an intermediate-ash product suitable for plant fuel or steam generation. The two-compartment washer produced a premium anthracite product and a middlings product. The sharpness-of-separation values ranged from good to excellent for the five primary separations and for the secondary separation.

Jan 1, 1968

By W. T. Millar

Graphite in the Suffern deposits near Hillburn, N. Y., consists of flakes ranging in size from fines to one-half inch in diameter. The Bureau of Mines investigated the Suffern deposits in the spring of 1943. Gneiss outcrops were examined, and five trenches excavated and sampled. The graphite is not confined to any definite zone but occurs in small, local pockets. Eleven samples were collected and combined for laboratory tests. Tests by the Bureau of Mines indicate that the graphite ore can be beneficiated by stage crushing, "skin flotation" of coarse flakes, and wet flotation of minus 10-mesh flakes. Over 90, percent of the graphite was recovered.

Jan 1, 1949

By H. H. Schrenk

[A calorimetric method3/ for the determination of benzene in amounts as low as 0.001 m has been developed recently at the U.S. Bureau of Mines Pittsburgh Experiment Station by the authors, with the assistance of chemical personnel from the Allegheny County (Pa.) Relief Works Division. The method is based on the direct nitration of either liquid or gas - phase benzene, followed by neutralization, extraction with butanone, and final treatment with sodium hydroxide which produces a violet color. The color is matched with color standards of known values. Although the method is adaptable to many conditions the primary objective was a procedure that would be suitable for hygienic investigations.]

Jan 1, 1935

By B. J. Dalton

This report gives general expressions for evaluating various thermo-dynamic properties applicable to a two-component system, including liquid-vapor equilibria. In addition, expressions are developed for some of the quantities useful in making thermodynamic consistency checks on phase equilibria data. These formulas were developed from the general principles of thermodynamics and are expressed in terms of the compressibility factor, which is assumed to be an explicit function of the molal density, the absolute thermodynamic temperature, and the composition.

Jan 1, 1968

By C. Melvin Lepper

A solid-state amplifier for the bridge circuit of an atomic-absorption mercury detector is presented and described. Operational advantages over previously used circuitry include improved time and temperature stability, increased measurement accuracy, and simplified setup, calibration, and operation.

Jan 1, 1972

By J. Gautam, T. Ong, W. E. Wallace, M. Keane, S. Xing, J. Harrison

"INTRODUCTIONOrganics extractable from respirable diesel exhaust soot particles by organic solvents have been known for some time to be direct acting frameshift mutagens in the Ames Salmonella typhimurium histidine reversion assay (Huisingh, et al). Upon deposition in a pulmonary alveolus or respiratory bronchiole, respirable diesel soot particles will contact first the hypophase which is coated by and laden with surfactants. To model interactions of soot and pulmonary surfactant, we dispersed soots in vitro in the primary phospholipid pulmonary surfactant dipalmitoyl glycerophosphorylcholine (lecithin) (DPL) in physiological saline. We have shown that diesel soots dispersed in lecithin surfactant can express mutagenic activity, in the Ames assay system using S. typhimurium TA98, comparable to that expressed by equal amounts of soot extracted by dichloromethane/ dimethylsulfoxide (DCM/DMSO)(Wallace, et al, 1987). Here we report additional data on the same system using additional exhaust soots and also using two other phospholipids, dipalmitoyl glycerophosphoryl ethanolamine (DPPE), and dipalmitoyl phosphatidic acid (DPPA), with different ionic character hydrophilic moieties. A preliminary study of the surfactant dispersed soot in an eucaryotic cell test system also is reported.MATERIALS AND METHODSSoots D4 and D6 were collected at two different times as scrapings from the exhaust pipe of a diesel tractor-trailer immediately after the engine was stopped. Surfactant dispersions were made by ultrasonic probe sonicating 25 mg of commercially obtained DPL, DPPE, or DPPA into 1O ml of O.85% physiological sterile saline (PSS) for 10 min at 40 watts power. For surfactant dispersions, 2.5 mg soot was mixed into 2.5 ml of the appropriate phospholipid dispersion. Mixtures were sonicated by 40 watts sonicator probe for one min, then incubated in the sonicator water bath for 30 min at room temperature; the mixture was then incubated for one hour at 37C while being rotated continuously. Dilution series were made with saline. For solvent extraction, 2.5 mg soot was mixed into 2.5 ml of DCM and incubated in a sonicator water bath for 30 min at room temperature. The sample was then mixed with 2.7 ml DMSO, placed in a dry bath at 45C, and the DCM evaporated under a stream of nitrogen gas until 2.5 ml of liquid remained. Ames salmonella/microsome assay utilizing TA98 for frameshift mutation was used for mutagenicity testing, with and without S9 activation, as described by Ames et al (1975). Unfiltered sample extractions or dispersions were preincubated with tester cells for 90 min at 37C : 0.1 ml of sample was mixed with 0.5 ml of PSS, or of S9 mixture, and 0.1 ml of an overnight TA98 culture incubated samples were then added to 2 ml of top agar supplemented with biotin and a trace amount of histidine, and overlayed onto Vogel-Bonner minimal media plates. After 48 hours incubation at 37C, revertant colonies were counted. Solvent controls were DMSO, DPL, DPPE, DPPA, and saline. Positive controls were trinitrofluorenone (1 ug/plate), for samples not treated with S9, and 2-aminoanthracene for S9 treated samples (2.5 ug/plate). All samples were assayed in duplicate. Sister chromatid exchange (SCE) assay was performed, following Lett, et al (1981), using V79 cells, of Chinese hamster pulmonary fibroblast origin. Stock diesel sample suspensions were made as 10 mg soot/ml DPL suspension, or 20 mg soot/ml in DMSO. Aliquots of these soot preparations were added to 15 ml of culture medium per sample flask to result in concentrations of 25, 50, and 75 ug soot/ml medium. After 12 hours incubation, 200 ul of 25 uM 5-bromodeoxyuridine (BrdU) was added to each flask. After another 35 hours incubation, 200 ul of 10 ug/ml colcemid were added; and the cells were harvested three hours later. Cells were swollen by hypotonic saline, and fixed twice with methanol/acetic acid, and burst on microscope slides. Cells on the slide were stained with Hoechst 33258, exp"

Jan 1, 1990

By Peter F. Steidl

As part of the Bureau of Mines methane control program, the Upper Free- port coalbed was studied in Fayette County, Pa., where this coalbed lies about 650 feet below the Pittsburgh coalbed and contains the largest remaining reserves of any coalbed in the county. Coal and overburden isopachs, structure and joint pattern maps, and a fence diagram were prepared using data from gas and oil exploration logs and coal outcrops. These maps will aid in determining the need and/or feasibility of degasifying the Upper Freeport coalbed in the study area. Much of the coalbed in this area is under 600 to 1,400 feet of overburden. By correlation with data from the Pittsburgh coalbed, the gas content at depths of this order is estimated to be between 140 to 300 cf/ton of coal, for a total of 190 to 400 billion cubic feet of methane in this coalbed in Fayette County.

Jan 1, 1977

By W. Wallace, T. Ong, M. Gautam, M. Keane, S. Xing, J. Harrison

"Diesel exhaust soots were assayed in the Ames Salmonella typhimurium histidine reversion assay system using TA 98, the soots being applied as the following preparations: dispersion in dipaimitoyl glycerophosphoryl choline (DPL), dispersion in dipalmitoyl phosphatidylethanolamine (DPP!), and dispersion in dipalmitoyl phosphatidic acid (DPPA) in physiological saline, and in physiological saline without added surfactant. The extracts of soots by dichloromethane / dimethylsulfoxide (DCM/BHSO) were also assayed. Studies were performed both with and without :IQ microsomal activation of the soot preparations. The DPP! and DPPA surfactants were chosen as phospholiridz with two palmitic acid moieties esterified to a glycerol as is the case with DPL, but with hydrophilic groups having different electrophilic characters. The soots, without S9 activation, showed mutegenic activity when extracted in the conventional procedure with DCM/DMSO. The mutagenic activity of soots dispersed in DPL was quantitatively comparable to, and in some cases greater than, the activity expressed by an equal mass of soot extracted by DCM/DMSO. Soots in other surfactantpreparations, DPP! and DPPA, also expressed positive mutagenic activity. Praincubation with S9 microsomal enzyme fraction reduced the activity of solvent extracted soots, and greatly diminished the activity of DPL dispersed soots. Initial sister chromatid exchange (SCE) assays using the Chinese hamster V79 cell line indicated DPL dispersed soot also can cause SCR in mammalian cells. Results thus far suggest that surfactant suspended or ""solubilized"" respirable soot particles could provide a mechanism for transport and expression of mutagens in the lung."

Jan 1, 1989

By H. H. Schrenk

[A colorimetric method5/ for the determination of benzene in amounts as low as 0.001 mg has been developed recently at the U.S. Bureau of Mines Pittsburgh Experiment Station by the authors, with the assistance of chemical personnel fro a the Allegheny County (Pa.) Relief Works Division. The method is based on the direct nitration of either liquid - or gas - phase benzene, followed by neutralization, extraction with butanone, and final treatment with sodium hydroxide which produces a violet color. The color is matched with color standards of known values. Although the method is adaptable to many conditions the primary objective was a procedure that would be suitable for hygienic investigations. The development worth included a study of possible interference by chemicals that be present in those situations in which the method. would be employed. In this study it was found that a specimen of hexane prepared by the Gulf Research Laboratory, Pittsburgh, by fractionation of West Virginia natural gas gave positive result for benzene, whereas a specimen of pentane prepared in the same manner showed only a trace, and specimens of n -heptane and octane (2,2,4 trimethylpentane) supplied by Eastman Kodak Co. save a negative result. According to information obtained from the Eastman Kodak Co. the latter two compounds were highly purified, the n-heptene being prepared from line and the octane synthesized in the laboratory. On nitration of a larger amount of tae natural hexane a visible quantity, of needlelike crystals which resembled those of m-dinitrobenzene was obtained. The hexane from this nitration was recovered by distillation and again nitrated, but no crystals or colorimetric indication of benzene was obtained. This imitated that the specimen of natural hexane contained a substance which at least had the chemical behavior of benzene.]

Jan 1, 1935

By H. E. Powell

Because of increasing consumption of high-and super-duty refractories, the Bureau is studying the feasibility of beneficiating submarginal and marginal clays. Diverse mineral dressing tests were used to beneficiate samples from the east-central Missouri fire clay district. Standard ASTM tests were used to determine refractory properties of both crude and beneficiated clay samples. Marginal and submarginal clays containing impurities were effectively beneficiated by both wet-cyclone and wet-table treatment, but the wet-cyclone treatment was cheaper. Ion-exchange resins in the hydrogen form will probably prove more effective in removing potassium, the only alkali in Missouri fire clays to be a problem. Resins with greater cross linkage are more effective than resins with less. Roasting the crude clays before removing alkalis by chemical leaching was ineffective. By applying ultrasonic energy at a frequency of 10 to 25 kilocycles to aqueous suspensions of the clays, subsequent ion-exchange extraction of potassium was slightly improved. Higher frequency ranges did not help.

Jan 1, 1963

By A. R. Taylor

The Bureau of Mines has determined the heat capacity and enthalpy values for beryllium sulfate (BeS04) throughout the temperature ranges of 10° to 300° K in an adiabatic calorimeter, and 350° to 860° K in a Bunsen-type ice calorimter, The heat-capacity data were extrapolated to 0° K, and smooth values of heat capacity, entropy, enthalpy function, and free-energy function were reported at 10-degree intervals between 0° and 300° K. The method of least squares was used to fit the enthalpy data with an algebraic equation. The equation also was used to calculate values of heat capacity, entropy, enthalpy function, and free-energy function at 50-degree intervals between 300° and 900° K.

Jan 1, 1963

By L. W. Higley

Procedures were developed for reclaiming high-temperature alloy scrap in the form of standard cobalt-base alloy. A cobalt-base, multicomponent, high- temperature alloy, such as S-816, can be successfully melted from scrap, and its specified chemical composition can be retained. Induction furnace melting in a controlled atmosphere was used to obtain ingots that were subsequently fabricated by impact forging to provide specimens for heat treatment and testing. Of the numerous metal elements in S-816 alloy, only small quantities of molybdenum were lost in the melting operation as finally developed. Test results indicated that the scrap material, after melting, forging, and heat treatment, was equivalent in room-temperature tensile strength, in high-temperature creep and stress-rupture properties, and in chemical composition to commercially produced S-816 alloy made from virgin material.

Jan 1, 1963

By Clarence O. Babcock

This report describes the results of a Bureau of Mines investigation in which an elastic inclusion, orebody, or mining system is replaced for purposes of analysis with an imaginary effective inclusion of rectangular shape that encloses the region. This effective inclusion has averaged physical properties that are directly related to the average inclusion stresses. The results were in excellent agreement with those predicted by Donnell's theory (2)2 for an isotropic elliptical inclusion in a state of plane strain for all height-to-width ratios and for all degrees of inclusion hardness from very soft to very hard. The results are exact for an isotropic circular inclusion and provide an easy method of evaluating the stresses obtained by cylindrical inclusions in boreholes when the Poisson's ratio for both host and inclusion equals 0.25 for plane strain or 0.333 for plane stress. The theory was also used to predict the average stresses in 48 finite-element models of single transversely isotropic inclusions of ovaloid and rectangular shape. An interesting and useful observation from this work was that the forces on elliptical inclusions in the x and y directions, produced by applied uniaxial stresses in the y and x directions, respectively, were equal in magnitude but opposite in sign when the applied stresses were equal. This occurred when the plane strain condition was used with a Poisson's ratio of 0.25. The practical usefulness of the method is given by treating a variety of mining problems: (1) The average stresses in an orebody of irregular shape; (2) the average stresses in single-level room-and-pillar mining systems; (3) the average stresses in multiple-level room-and-pillar mining systems; (4) the effect of mining sequence on the average stresses produced during mining; (5) the stresses in cylindrical borehole plug related to host rock stresses as a function of plug hardness; and (6) methods for simplifying finite-element analysis of complex structures.

Jan 1, 1974

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

By W. E. Miller, Kennedy. R. E., G. W. Jones

"INTRODUCTION Ethyl mercaptan (CH3,CH2SH), a combustible organic liquid of the thioalcohol type, is employed at an odorant in many types of fuel gases and dangerous atmospheres, which in themselves are devoid of characteristic odors, to give warring against leakage of such gases or atmospheres into places where they might constitute health or explosion hazards.Ethyl mercaptan has a penetrating disagreeable odor resembling that of onions, garlic, hydrogen sulfide, or rotting cabbage, that exceedingly low concentrations of it can be detected. The of odorants as a beans of detecting leakage of gases and atmospheres has been investigated extensively by chemists and engineers of the Bureau of Mines, and numerous reports as to its value have been published."

Jun 1, 1942

By Edward D. Thimons

Several types of inflatable stoppings, developed under Bureau of Mines contract for use as mine air barriers during underground production, have been tested by the Bureau. All of the stoppings tested showed significant internal leakage initially but, in all but one stopping, the leaks were sealed with limited effort The stoppings were tested underground in two western noncoal mines under production conditions. The results from the Colorado molybdenum mine showed the stoppings to be generally unsatisfactory for daily mine usage if they are deployed near blasting areas or in locations where near-perfect air seals are required. They were very susceptible to blast damage and seldom were better than 90 percent efficient as air barriers. However, stoppings tested in the New Mexico uranium mine were located substantially distant from any blasting. Because slight leakage past the stoppings was acceptable, they proved very satisfactory in that application.

Jan 1, 1976

By Kenneth H. Johnston

Information and data necessary for research on improving methods of oil recovery from low-permeability reservoirs and for comparison and evaluation of performance of such reservoirs with those producing from more permeable sands were obtained. Core analyses, well logs, production tests, well stimulation techniques, primary and secondary production records, and data on two water-flood projects were examined for wells producing from the Bartlesville sand, West Avant field, Osage County, Okla. Overall recovery from the study area was generally poor with only 9.0 percent of the pore volume recovered to January 1, 1968. Larger fracture treatments (8,000 to 12,000 gal) could have resulted in an increase in primary oil recovery. Secondary recovery by water-flooding accounted for only 1.9 percent of the pore volume because of the inability to control the large volume of injection fluid that escaped from the flood patterns and the excessive volumes of water produced with the oil. Future waterflood development in other low-permeability reservoirs should include the drilling of new input wells, use of injectivity surveys to locate possible natural fracture systems, or zones of high permeability, and control of injection fluids by altering flood patterns and/or plugging of the more permeable zones.

Jan 1, 1968

By R. E. Lindstrom

Separation efficiency of a 4 percent divinylbenzene (DVB) resin is not altered over a wide range in temperature. A 12 percent DVB resin, however, exhibits a marked sensitivity to temperature. When flow rates are high at ordinary temperatures, 4 percent DVB resin exhibits higher efficiency, but at 200° F. both resins are equal in performance. Effective separation of rare-earth mixtures may be obtained with hydrogen as a retaining ion by maintaining column temperatures above the solubility of ethylenediaminetetraacetic acid (EDTA) in the free acid form. Slightly lower separation characteristics were obtained with this method as compared with copper as a retaining ion, Recovery of 99 percent of the EDTA from spent eluting solutions that contain copper has been accomplished by a calcium-copper displacement reaction followed by EDTA precipitation. Impurities in the product are correspondingly low. Recoveries of EDTA from holmium solutions with sulfuric acid are substantial; however, those from yttrium solutions are quite modest. Radiotracer experiments show the presence of approximately 0.1 percent yttrium contamina¬tion in the recovered material. The study presented is one phase of a broad research program designed to assist the technology of separating and purifying rare-earth elements.

Jan 1, 1961

By Martin Hertzberg

The Bureau of Mines 8-liter flammability system was used to study the effectiveness of a variety of powdered inhibitors in preventing the propagation of explosions of coal dust or methane in air. Over 35 different chemical additives were evaluated against Pittsburgh seam pulverized coal. The least effective inhibitors were the carbonates, which required mass additions in the range of two to three parts inhibitor to one part of coal dust in order to prevent propagation. The most effective inhibitors were the derivatives of ammonium phosphate, which were effective quenching agents at additions of only one part inhibitor to four parts of coal dust. Alkali halide powders were of intermediate effectiveness. These laboratory-scale results are in good agreement with full-scale mine experiments in all cases where detailed comparisons have been made. Data were also obtained for the effectiveness of several of the same powdered inhibitors against methane-air explosions. Their relative order of effectiveness and the concentration ranges required for quenching the gas explosion are comparable to those measured for coal dust explosions. Data are also presented for the effectiveness of N2 and CF3Br addition. Some preliminary data are also presented for powder addition to methane burner flames. Those data are compared with other burner data and evaluated in terms of their relevance to explosion tests.

Jan 1, 1982