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By H. H. Schrenk

There is a need for a method of determining benzene vapor in air which is simple and accurate and suitable for making industrial hygiene surveys. The most widely used method in this country is the Smyth modification of the Elliott and Dalton procedure. This depends on the nitration of the benzene to m-dinitrobenzene, reduction to phenylenediamine with an excess of standard titanous chloride solution, and back titration with a standard ferric ammonium sulphate solution. This method has the disadvantages of being somewhat time-consuming and cumbersome; it requires considerable apparatus, and a special modification is necessary in the presence of toluene. Recently Cook and Ficklen have published a method based on the oxidation of benzene with hydrogen peroxide in the presence of iron salts. This method requires the use of solid carbon dioxide to freeze out the benzene. The reaction Which produces the color is complex; and only approximate quantitative estimations can be made, except in a very narrow range.

Jan 1, 1935

By C. Pritchard

John Marks said in his acceptance of the Hartman Award in 2008, "I guess that without the occasional complaint, your mine is probably over-ventilated" (Marks, 2008). Miners are seldom in this situation and spend much of the time trying to find enough air to keep an operation running. With examination, there are usually changes that can be made to increase the efficiency of ventilation systems. Mine ventilation air is a costly commodity, especially by the time it has been heated or cooled and moved to the bottom of the shaft and through the mine airways. Modifications that result in surplus mine ventilation air could bring financial and environmental benefits. Some issues mine operators have needed to address recently are increased airflow requirements to dilute diesel particulates in metal and nonmetal mines, to ventilate reserves that are deeper, hotter, and further away from fans and shafts, and to meet demands from increased production. This paper discusses successful methods to find additional usable air when there is no extra ventilation capacity. Most of the options presented in this paper are useful for metal/ nonmetal operations but some may be applicable to coal as well.

Jan 1, 2010

By Noel N. Moebs

Studies by the Bureau of Mines have identified geologic structures in mine roof rock that contribute to many roof falls in Appalachian coal mines. These structures, including paleochannels, scours, pinchouts, slickensides, clay veins, crevasse splays, and joints, can often be identified during, and sometimes before, mine development. Mine projections can be revised to reduce the adverse effects of discontinuitites in roof structure; large roof areas of laminated sandstone or incompetent strata generally can be delineated or inferred from exploratory drill hole data, and the need for supplementary support can be anticipated. Accurate descriptions of roof geology also provide some indication of optimum length and type of roof bolts that should be installed.

Jan 1, 1981

By Douglas A. Elkins

The unique characteristics of plasmas, their current applications, and ongoing research into new applications are described. Major technical and economic problems in application of plasma technology are discussed. Examples of potential applications of plasma in extractive metallurgy are described and evaluated. The report includes a selected bibliography of articles on plasma and related high-temperature technology.

Jan 1, 1969

By George Saliba

This report disucsses the formulation of a mathematical model for the steering of a conveyor belt by a flat return idler and a troughed idler under various loading conditions. Significant parameters associated with belt training are identified. The generation of a skewed flat return idler model in terms of a steering force and self-aligning torque is presented. Development of the mathematical model for the flat return steering idler is illustrated for the case of no circumferential slip occurring and for the assumption of a bidirectional slip mechanism. Experimental results supporting the theoretical analysis is presented.

Jan 1, 1977

By James F. O'Neill

Brown iron ore deposits in Quitman County , Ga . , were investigated by the Federal Bureau of Mines in cooperation with the State of Georgia , Department of Commerce , and the University of Alabama . Ninety- one holes were drilled , having an aggregate footage of 2,188 feet ; seventy- one holes penetrated 248 feet of iron mineralization . Average thickness of the ore zone was 3.5 feet under an average thickness of 14.7 feet of overburden . The drilling developed inferred reserves containing nearly 30 million long tons of crude ore with an average analysis of 28 percent iron plus minor quantities of manganese . Test work done by the Bureau on the crude ore samples indicated that they would upgrade by current log washer practice , with the use of a 1 /8 - inch screen , and yield 4.4 million dry long tons of concentrate with an average analysis of 52.1 percent iron plus manganese . The weight recovery obtained was 14.7 percent . Research studies made by the Bureau showed that the weight recovery would be increased by changing the screen size without any appreciable sacrifice of grade . The average weight recovery was increased to 18 percent with a 10 - mesh screen and 22.8 percent with a 20 - mesh screen . Screen tests studies indicated that there was no appreciable interlocking of the iron and manganese minerals and the clay and silica waste particles of the materials retained on a 200- mesh screen . Clay was prominent in micron - size slimes . Silica was deleterious in the minus 20 - mesh size .

Jan 1, 1965

By E. J. Matson

The Bureau of Mines has been investigating deposits of critical and essential minerals in the United States since 1939. The Rush Creek lead-zinc deposit, Mono County, Calif. (fig. 1), was examined by W. T. Benson in July 1944 and again in September 1945 by D. W. Butner, engineers of the Bureau of Mines. From the results of these preliminary examinations, a core-drilling program (fig. 2) was started in August 1946 and continued until November 1946, when work was stopped on account of inclement weather. Field work was again started in May 1947 and completed in June 1947. The drilling program was laid out to develop the horizontal .and vertical extensions of showings exposed in surface pits.

Jan 1, 1949

By Lewis V. Wade

This report provides background information concerning a mine roof simulator currently being considered by the Bureau of Mines. The simulator is a mechanical device with the ability to simulate the forces and displacements associated with mine roof over an area 20 by 20 feet. The topics covered in the report include a conceptual description of the system, definition of system capabilities, discussion of how such capabilities were decided upon, description of available control modes, and a comparison between the mine roof simulator facility and similar facilities existing elsewhere.

Jan 1, 1974

By M. L. Glenn

The Bureau of Mines is conducting research on Fe-based alloys using Si and Al additions to reduce the Cr required for heat-resisting appli-cations. Part of this research is being done to evaluate alloys containing (8-10)Cr-(10-14)Ni-(0-8.5)Si-(0-4) Al to determine which of these alloys have austenitic structures, as well as fabrication properties and oxidation resistance sufficient to substitute for type 304 stainless steel. Based on initial results, an Fe-lOCr-11Ni-5Si alloy and an Fe-8Cr-13Ni-5Si alloy were selected for evaluation of oxidati.on, stress rupture, and tensile properties. Both alloys have oxidation resistance at 7000 and 8000 C that is better than that of type 304 stainless steel. The stress rupture strengths are less than that of type 304 stainless steel but significantly better than that of commercial heat-resisting steels with similar Cr contents. Yield strengths of the alloys were equivalent to that of type 304. Both alloys had high tensile strengths comparable to those of stainless steels that transform to martensite during straining (e.g., type 301). These alloys have weld-hot-cracking resistance comparable to that of type 304 stainless steel. This initial study shows that Si has potential as a substitute for Cr in stainless steels for heat-resisting applications.

Jan 1, 1984

By Donald R. Corson

The Bureau of Mines is conducting research on the effects of various established and potential soil-stabilization additives to hydraulic backfill. This initial phase is an evaluation of the effect of inclusion of varying amounts of Portland cement and combinations of cement and a dispersant on the bearing strength of backfill. Results of unconfined compression tests are given for over 200 sample cylinders incorporating a fill material with cement or cement and dispersant. Inclusion of a minor amount of dispersant (0.2 percent by weight) is found to yield a significant increase in strength for 20-to-1 and leaner sand-cement mixes. An apparent optimum concentration of dispersant exists beyond which no further increase in strength is achieved. A dispersant-cement ratio of l.8- to-1 yielded a strength increase of 515 percent over the strength of untreated 40-to-l sand-cement mixes.

Jan 1, 1966

By Hillary W. St. Clair

This report describes an experimental method for determining parameters for the rate of reaction of CO2 with solid carbon. The method involves the simulation of a flow reactor by a mathematical model based on a hypothetical multistage reactor which permits calculation of the analyses of effluent gas and carbon consumed as functions of the flow rate and duration of the reaction. The method is applied to experimental data on the reaction of coke with CO2 in fluidized-bed and fixed-bed flow reactors. A method is described whereby two parameters may be determined simultaneously. The method involves a reiterative procedure that finds the values of the parameters that minimize the sum of squares of deviation between calculated and observed analyses of the effluent gas.

Jan 1, 1971

By Oliver Bowles

This report covers the character, properties, origin, occurrence, and uses of the traprocks and describes briefly the methods and equipment employed in quarrying and preparing them for market. Production of traprock occupies an important place in industry. In 1960 the output in the form of crushed stone reached nearly 58 million tons valued at $87 million. Traprocks are also shaped into blocks of dimension stone for monuments, building construction and decoration, and specialized products such as surface plates.

Jan 1, 1963

By J. P. Powell

This report provides information on the techniques and results obtained on representative waterflooding projects in Cowley County, Kans. Records show that waterflooding was begun as early as 1935, but not until 1948 was the method expanded. The greater depths to the oil-producing formations in this area compared to those in eastern Kansas undoubtedly delayed the widespread use of secondary-recovery methods. This report presents a discussion of four waterflooding projects in Cowley County, Kans. The locations of these projects are shown in figure 1. The projects have been in operation from 1 to 7 years and have produced more than 1 million barrels of additional oil by injecting 11.5 million barrels of water. The projects are designed to take advantage of elevation and height of the separator tank to collect by gravity flow the produced brine at the respective treating or storage tanks. The closed-type water system is used on three of the projects and an open-type water conditioning system on the fourth. On one of the projects, which was drilled along a narrow shoestring formation, alternate well, were converted to input wells. However, most of the input wells for flooding converted producing wells.

Jan 1, 1958

By J. D. Davis

The carbonizing properties of No. 2-bed coal from the Bartoy mine and No. 5- or Miller-bed coal from the Wilkeson-Miller mine, both at Wilkeson, Pierce County, Wash., were determined by the Bureau of Mines-American Gas Association (BM-AGA) method. Tests were made in the 13-inch retort at 500°, 600°, and 700° C. and in the 18¬inch retort at 800°, 900°, and 1,000° C. Fischer low-temperature and United States Steel Corporation high-temperature assays were made and the results compared with those of the BM-AGA tests at corresponding temperatures. Agglutinating and plastic properties were determined, and chemical and petrographic analyses were made. The No. 2 bed is 58.5 to 88.0 inches thick at three points sampled in the Bartoy mine. The coal is 98 percent bright and contains only a trace of fusain. A composite of three mine samples contained 13.8 percent ash. The washed sample, which was used in the tests described herein, contained 11.4 percent ash, 2.2 percent moisture, and 0.6 percent sulfur upon the as-carbonized basis and 68.4 percent fixed carbon upon the dry, mineral-matter-free basis. The heating value was 15,183 B. t.u. per pound upon the moist, mineral-matter-free basis. No. 2 therefore ranks as a high-volatile A coal and is very high in that, rank. The ash softens at 2,910° F. Except for its ash content, which is higher than the limit of 9.0 percent specified by the American Society for Testing Materials, No. 2 coal fulfills the requirements of a coking coal. It also is classed as extremely friable, the friability being 88.0 percent. The agglutinating index (7.6 for the 15 : 1 ratio of silicon carbide to coal) is high, and the plasticity as indicated by the Gieseler test (60 divisions per minute) is low for a high-volatile A coal.

Jan 1, 1942

By J. M. Mutmansky

"The objective of this study was to produce coal dusts for laboratory research that are similar to mine airborne dusts in chemical, mineral, and physical characteristics. In this investigation, dusts produced in laboratory comminution equipment were compared with continuous miner- generated dust for similarity in physical characteristics. Mining-generated dust (MGD) and bulk coal samples were first collected from an underground mining operation. The bulk samples were then processed in the laboratory for size reduction in various comminution devices. These laboratory- generated dust (LGD) samples were subjected to size and microscopic analyses. Physical properties of the dust particles were studied on a scanning electron microscope (SEM ). A numerical shape coordinate system (SCS) was also developed and applied to 300 particles from each sample. Statistical analysis was then performed on the collected data and characteristics of the MGD and LGD samples were compared. IntroductionIn many biomedical studies, researchers routinely introduce a dust mass into an experimental environment to assess the response of a biological entity, usually lung macrophages in vitro or a live laboratory animal, to the dust mass. To provide data of maximum usefulness, it is highly desirable to use dust with characteristics of actual mine airborne dust. The primary objective of this research was to produce dusts in the laboratory similar in chemical, mineralogical, and physical characteristics to mine airborne dusts. This paper outlines the evaluation of the physical characteristics of the lab-generated dusts.Particle shape analysis is perhaps the least-developed area in mineral-related particle science and technology. There are still no standard methods or instruments to scientifically quantify particle shapes. To date, many attempts have been made to characterize particle shapes. These procedures can be roughly classified into three categories:"

Dec 1, 1995

By W. E. Robinson

A laboratory study wan made to determine whether drying and preheating Colorado oil shale with waste retort gases has any appreciable effect on its oil yield. Samples of crushed oil shale were heated at subretorting temperatures in a specially constructed electric furnace by gases similar in composition to waste gases from oil-shale retorts. The results of this study showed that preheating oil shale with nitrogen or a reducing mixture had no effect upon the oil or water yield. However, oxygen in the preheating gas caused a decrease of oil and an increase of water. In general, the oil yield decreased with (1) increase in oxygen content of the heating gases, (2) increase in temperature of the heating gas, (3) increase in heating time, and (4) decrease in the particle size of tho shale. The decrease in oil and the increase in water resulting from preheating were due to oxidation of the benzene-insoluble organic material (kerogen) rather than to oxidation of the benzene-soluble organic material (natural bitumen) in the shale, A small amount of oil was volatilized during preheating, which would constitute an additional loss if prober precautions were not taken to recover it. The results obtained in this laboratory study indicate that oil shale can be preheated without appreciable decrease in oil yield by proper selection of preheating conditions.

Jan 1, 1951

By O. M. Bishop

"SUMMARYAs a result of the increased demand for fluorspar during the war, the Bureau of Mines investigated numerous fluorspar properties in the southern Illinois field, which is centered in Rosiclare. Among these the J. J. Shelby 40-acre tract on the western edge of the district presented favorable factors that caused it to be chosen /or exploration.H. G. Spiller, formen lessee of the property, had explored the Shelby vein by means of an adit level and winze, and showed it to contain goad values in zinc and fluorspar at the depth explored. A diamond-drill hole with which Spiller explored the vein 78 feet southwest of the winze, however, failed to cut ore. After studying the field evidence, the Bureau concluded that the vein merited further exploration, particularly at a depth of about 440 feet, where the Fredonia limestone would form the foot-wall of the vein and the hanging wall would be the competent Cypress sandstone.Between October 17, 1944, and March 26, 1945, three diamond-drill holes were bored for a total inclined depth of 1,592 feet. Holes 1 and spaced approximately 500 feet apart, explored the vein at 440 feet 4 below the surface. The economic mineralization existed in the vein where cut. Hole 3 cut the fault at approximately 300 feet below the outcrop but failed to find any vein matter except stringers of calcite with small amounts of pyrite."

Apr 1, 1947

By Joan T. May

The Federal Bureau of Mines investigated the potential for recovering aluminum from copper-dump leach liquors by use of single-contact ion-exchange technology. A strongly acidic ion-exchange resin was used to extract aluminum from a typical dump leach liquor and from synthetic leach liquors. Aluminum was stripped from resin with a HS04 or NaCl solution. Bench-scale experiments indicate that a single-contact ion exchange is technically feasible, but that the process is limited by the relatively low loading capacity of the resin and the excessive amount of stripping agent required. A further limitation is that significant amounts of magnesium and iron are loaded and stripped along with the aluminum.

Jan 1, 1976

By Robert Bottge

When a company develops a mineral property in a remote area of Alaska, it must consider how best to house its personnel. This Bureau of Mines report examines the economics of two options: company towns and company camps. The price required to maintain a 15% discounted-cash-flow rate of return (DCFROR) was derived for hypothetical 1,000-st/d cut-and-fill mines and 50,000-st/d open-pit mines located in three different regions of the State, One set of hypothetical mines utilizes a townsite; the other utilizes a relatively new concept, a fly-in camp or commuting operation, in which two shifts of employees operate the mine and all associated facilities for 1 week before being replaced by a second crew. The study shows that operating costs were higher for mines employing the commuting option than for mines having a company town because of the additional wages paid for overtime hours; however, the price required to obtain a 15% DCFROR for the single-product copper concentrate, f.0.b. the mill site, was significantly lower owing to the lower investment costs for the camp-type operation. The economic advantage for those mines utilizing the camp increases from south to north and from the coast toward the interior.

Jan 1, 1986

By D. W. Butner

This Information Circular , one of a series published by the Bureau of Mines , reports on the methods and costs of mining and concentrating zinclead ore at the Highland Surprise mine in the Pine Creek area of the Coeur d'Alene region of Idaho . The mine is owned and operated by the Highland Surprise Consolidated Mining Co. , which supervises operations of the Nevada Stewart group of claims , which is adjacent on the northwest . These properties are at the extreme eastern end of a zone of fracturing that strikes northwest across the Pine Creek area . In fractures along this zone are the principal Pine Creek mines ; these are the Highland Surprise , Nevada Stewart , Sidney , Denver , V and Idaho , Liberal King , and Northern Light . Country rock at the Highland Surprise is argillite of the Prichard formation (Belt series ) . Fracturing has permitted the movement of mineral- izing agents that have replaced adjacent walls and crushed country rock with sulfides . Ore minerals are sphalerite and galena with accessory pyrite , chalcopyrite , pyrrhotite , and siderite . Three principal ore shoots were found on the Highland Surprise property . The Highland ore shoot was mined from outcrop to the 400 level . The Surprise ore body has been developed to a depth of 1,400 feet on the dip of the vein . The outcrop of the Surprise ore shoot was 150 feet long and 2 to 4 feet thick ; on the 1,150 ( lowest ) level , the ore shoot is 320 feet long and 10 to 17 feet thick , with good zinc content . Surprise ore shoot No. 2 occurs 250 feet west of No. 1 and has been mined from the 500 to the 1,000 level . From 353,000 tons of ore mined between 1910 and 1948 , the property has a recorded production of 256,000 ounces of silver , 7,500 tons of lead , 24,000 tons of zinc , and 412 tons of copper . Both shrinkage and cut and fill stoping methods are used at the Highland Surprise , but shrinkage is unsuitable for mining below the 700 level , because faulting has weakened the walls . Development of the Surprise ore , as well as exploration laterally and along the strike , is prosecuted steadily . A prospect heading is being pushed westward toward Nevada Stewart ground from the 700 level . The mill has a rated capacity of 275 tons per day and operates near capacity . Selective flotation makes zinc concentrate that is shipped to the Anaconda smelter and lead concentrate that is trucked to the Bunker Hill smelter at Kellogg .

Mar 1, 1950