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By Martin H. Stanezyk

The Bureau of Mines investigated leaching of selected copper sulfide minerals and a composite of impure flotation concentrates at elevated temperatures and pressures with ammoniacal solutions. Copper 1 (tractions of 96 percent were obtained by leaching chalcopyrite at 75° C under oxidizing conditions for 60 minutes. An extraction of 99 percent of the copper contained in the composite concentrate was obtained by leaching the product for 90 minutes at 75° C. In tests of bornite, chalcocite, and covellite, 90 to 97 percent of the copper was extracted at 20° C provided an 8-hour reaction period was used. At 75° C essentially complete dissolution of the copper from these three minerals was accomplished in 60 minutes. Additions of ammonium sulfate to the leach solutions were required to obtain high-percentage extractions of the copper from bornite, chalcocite, and covellite. Although ammonium sulfate was not required when digesting chalcopyrite, copper extraction was enhanced and less free ammonia was required when ammonium sulfate was added to the leach pulps. The chemistry of leaching copper minerals was studied. It was C, termined that chalcocite altered to covellite as one step in the dissolution When leaching iron-bearing copper sulfides, hydrated iron oxide formed on the mineral surfaces, indicating that a diffusion process prevailed. No evidence of covellite was detected.

Jan 1, 1966

By Robert S. Sanford

This paper deals with truck haulage methods and costs at one of the many open-cut mines that are replacing rail haulage with heavy-duty trucks. At this mine, ore is trucked to a crushing plant, centrally located within one of the open-cuts. The requirements for efficient low-cost truck haulage are: Good trucks designed for heavy loads, adequate truck maintenance, smooth roads, and well-trained truck drivers The weighted average cost of hauling a long ton of ore to the crusher and the waste to the dump was reduced from $0.1993 in 1948 to $0.1114 during the last half of 1949, his corresponds to a cost per ton mile of $0.0864.

Jan 1, 1952

By F. F. Hintze

In the group of minerals used in making this study, the cyanite is associated with quartz, mica, and feldspar in the schist. The amount of quartz is variable, but it is always an abundant mineral. Both large and small crystals of quartz occur in irregular masses, rarely ever showing crystal outline. Mica Is of the clear and dark varieties, the larger crystals being dark as a rule, and the finer crystals of light color. The present mineralogical composition of the mina is rather variable, as most of the original biotite and muscovite have suffered alteration, and much secondary mica is present as a result of alteration of the original mica and other minerals present, especially the larger cyanite crystals. A large part of the mica now found in the ore is chlorite, with varying amounts of Jefferisite and others, especially sericite. These are in the form of aggregates, or felt-like intergrowths filling the spaces between the quartz, cyanite, and feldspar. The feldspar is plagioclase probably mostly albite. It is white, possesses good cleavage, and is one of the hard brittle minerals of the rock. It alters to kaolin, and sericite, and more or less of these alteration minerals are present within the feldspar crystals but not separated from them. The cyanite is of two varieties, distinguished by their colors as blue and white cyanite. The blue color varies in intensity, being a pronounced blue in some crystals and paler in shade in others. Some crystals have been seen which posses the blue color in one-half of their mass and are pure white or clear in the other half. The purity of the cyanite is probably not affected by the color, but it is difficult to detect the white cyanite in the ore by macroscopic examination, so that great care has to be exercised in the selection of the ore in the field. Of the above minerals, cyanite is the heaviest, having a specific gravity of 3.6; none of the others approach it in specific gravity. The usual as opiates of cyanite in the mica schists are garnet, magnetite, and tourmaline, but these have not been noted in the group of minerals treated, and their absence is a point of great value in favor of this ore, as they possess high specific gravities and interfere in separation processes, and if not separated they are detrimental because of their easily fusible character. Small amounts of apatite and titanite have been noted, but not enough to cause trouble.

Jan 1, 1931

By F. E. Cash

The Holmes Safety Association was organized and named in honor of the late Dr. Joseph A. Holmes, first director of the United States Bureau of Mines. The association is a national organization and operates through local, sectional, or State chapters in mining, petroleum, and allied industries. The National Council of the Holmes Safety Association consists of representatives of State councils and local chapters, with the Director of the Bureau of Mines as president.

Jan 1, 1929

By F. R. McDonald

This report presents a discussion of the spectra of 39 condensed thiophenes in which the structure includes at least 1 benzene ring. The vibrational bands present in three regions of the infrared spectra of these thiophenes were interpreted by comparing the similarities of the spectra of condensed thiophenes with the spectra of substituted benzenes. In the overtone-combination region 23 of the 39 condensed thiophenes had spectra which contained sufficient detail to be usable for correlating this region of the spectrum with the appropriate benzene spectrum. In the in-plane deformation region it was possible to make correlations for the vibrations of 18 of the 39 condensed thiophenes whose infrared spectra were studied. In the out-of-plane deformation region the C-H out-of-plane vibrations for hydrogen on benzene rings in the condensed thiophenes can be correlated using known data from substituted benzenes.

Jan 1, 1967

By Homer J. Ballinger

A multiple drill carriage or "jumbo," which is believed to be unique in both design and performance, was constructed and has been in use for the past year at the Bureau of Mines experimental oil-shale mine near Rifle, Colo. This jumbo mounts four long feed percussion drills and is so designed that two men can operate all four drills. Before the jumbo was placed in operation, a minimum of eight man-shifts was required to drill 72 fifteen-foot holes in headings 60 feet wide and 27 feet high. The sane round is now drilled by two men in about 6 hours. Over 500 feet of drilling per man shift is easily and consistently accomplished. Use of the jumbo has resulted in a 75 percent reduction in drilling labor and a substantially lower drilling cost.

Jan 1, 1950

By D. A. Reynolds, L. P. Rockenbach

"The method of analyzing light oil for benzene is fully described by Fieldner and others 4/ and Kester and Kolmes 5/. In this procedure, benzene is determined by shaking 20 cc. of the 79º to 81º C. boiling point cut from the fractionation of the refined light oil with 3 volumes of 98—percent sulfuric acid in an A. S. T. M. separator funnel of the type used for determining water in bitumi¬nous materials. After the mixture has been shaken 5 minutes it is allowed to settle at least half an hour and the acid is drawn off; the residual oil is reported as paraffins and the decrease in volume as benzene. The method has been found satisfactory for light oils from coals carbonized at 5000, 600°, and 7000 C. but does not give accurate, reproducible results for oils from the 800° C. tests.The content of benzene of the 790 to 81° C. cut is high, 90 to 95 percent, for 800° C. light oils, whereas for lower—temperature light oils it is considerably less. Benzene is the most difficult of the aromatics to sulfonate, hence the acid concentration must be maintained above 95 percent to insure complete sulfonation. Sulfuric acid (98 percent) reacts with benzene, but its reaction with paraffins at ordinary temperatures is negligible; however, more concentrated acid will attack paraffins and give erroneous yields of benzene. The reaction between benzene and sulfuric acid forms water that will dilute the acid. The effect of this dilution may be overcome by increasing the acid-to-oil ratio or increasing the strength of the acid. The latter, however, must not be used, because the stronger acid reacts with paraffins."

Mar 1, 1942

By L. R. Burdick

Sulfur compounds have long been recognized as damaging pollutants of the air. A number of investigations have been made to determine the amount of such compounds existing in the air of various cities; moreover, some study has been given to the conditions affecting the concentrations. This paper summarizes published investigation and includes a bibliography on the subject. The methods of obtaining data have differed to the type of sampling, analysis procedure, hour of sampling, number of locations, and number of determinations made. Sampling methods include both the continuous type, covering a day or a number of days, and what can considered the ?snap? type, covering very short periods. Continuous sampling has, given data representing the average concentration at the location chosen but no information regarding variations from hour to hour, are none that might be said to represent the average for a city. The snap-sampling method, while not giving a true average for any one location or area, has in some instances made available date regarding variations of concentration during different hours of the day and at various locations or zones within the area chosen. Although the sulfur compounds in the air nay include sulfur dioxide, sulfur trioxide, hydrogen sulfide, and organic compounds of sulfur, most investigators report on the basis of sulfur dioxide. This gas unites with moisture to form sulfurous acid.

Jan 1, 1939

By L. C. IlsLey

The work of the electrical section of the Bureau of Mines may be considered to have had its beginning in April , 1909 , when H. H. Clark was , appointed electrical engineer in the U. S. Geological Survey. The first manuscript prepared by members of this section was Miners Circular 5, which was issued in October , 1911. During each succeeding year additional papers have been published dealing with questions relating to electrical safety. Since 1916 the electrical section has also conducted laboratory investigations on flame safety lamps and gas- detecting devices and has published reports relating thereto . The following selected list of publications covering safety studies and activities of the electrical section has been prepared for the convenience of those who wish to keep themselves advised concerning electrical safety matters . The list includes only such publications as are applicable to present-day prac tices .

Jul 1, 1930

By H. W. St. Clair

In about 1930, Degussa applied for a patent on a process for the of oxides, carbides, sulfides, and other nonmetallic impurities by filtration in the molter state. The filtering media listed were wire screen, coke, and ceramic materials, and quartz. It was also suggested that filtration might be combined with chemical reaction between the metal and the filter medium or that might be added to the system. No patent was granted on the general scheme, but several years later a patent was granted on a continuous process purification of crude light metals, especially or alkali earth and their alloys. The melt was stirred at 1 temperature at which the impurities (such as oxides and salts) remained solid and the metal was drawn through a filter tube. The impurities collected under the filter and were removed by a screw conveyor. Crude sodium was purified by this process in Degussa's Knapsack plant. During the last war, when the refining of scrap became a very urgent Problem in Germany, experimental investigations were extended to separation of other metals and metallic compounds by filtration. Preliminary experiments seemed to confirm the opinion of Dr. L. Weiss that the principles of wet chemical filtration might be applied to a great extent in the purification of metal and alloys.

Jan 1, 1949

By M. E. Volin

The tungsten potentialities of the Combination mine were examined by a mining engineer of the Bureau of Mines in 1947. A report based upon his personal knowledge of the mine and the results of the examination contained recommendations for further investigation. This report presents factual data from Bureau of Mines field investigations begun in August 1947 and continued until December 1948, except for a 5-month recess during the first winter. The Combinat.ion mining property of 52 patented claims and 15 patented mill sites is in the Black Pine mining district, Granite County, Mont., 11 miles northwest of Philipsburg. The altitude in the mine vicinity is approximately 6,500 feet.

Jan 1, 1952

By George H. Holmes

Beryllium deposits in the northern Virgin Mountains , Clark County , Nev . , and Mohave County , Ariz . , about 70 miles northeast of Las Vegas , were investigated by the Bureau of Mines . The investigation indicated a widespread occurrence of beryllium- bearing pegmatites within an extensive belt of mica - schist . Several deposits with significant beryllium mineral concentrations were encountered . Only a few of the samples analyzed contained more than 1 percent beryllium oxide ( BeO ) ; in many of the samples , no beryllium was reported . The average tenor of samples from the more important occurrences was 0.25 percent BeO . Chrysoberyl is the predominant beryllium mineral in the pegmatite sills ; beryl predominates in the more massive bodies . Minute quantities of cesium and lithium minerals also occur , but no columbium , tantalum , or other rare minerals were found . Ore dressing tests on a composite sample containing 0.28 percent BeO which was representative of the pegmatite sills , indicated an 85 percent recovery of the chrysoberyl ( 70 percent recovery of total BeO ) by gravity concentration in a concentrate containing 17.6 percent BeO .

Jan 1, 1964

By N. S. Dalal, B. Jafari, F. Y. H. Green, V. Vallyathan

"Using electron spin resonance (ESR) spectroscopy we have carried out a systematic study of the measurement of concentrations of organic free radicals in freeze-dried lung tissue. Sixty-six tissue samples were obtained from the National Coal Workers' Autopsy Study (NCWAS). The samples were characterized in terms of the concentration per gram of the free radicals, and examined in relationship to the histopathological parameters such as age, numbers of years in the mining atmosphere, the degree of disease, and smoking history. Preliminary results indicate a positive correlation between the free radicals in the lung tissue and the severity of pneumoconiosis.IntroductionThis paper summarizes our electron spin resonance (ESR) measurements of the concentration of organic free radicals in the freeze-dried lung tissue of autopsied coal miners. This work was undertaken because it is well known that most coals contain carbon-centered organic free radi¬cals,(1,2) and recent studies from our laboratories indicated that reactive free radicals might play a role in the biochemi¬cal mechanism of coal workers' pneumoconiosis (CWP) (3) Thus we obtained 144 lung-tissue samples from the Nation¬al Institute for Occupational Safety and Health (NIOSH) in Morgantown. The samples came from the data bank of the National Coal Workers' Autopsy Study (NCWAS). This selection was unique because fairly detailed histopathologi¬cal information was available for each sample.Other recent studies in this field are those of Ohta et al (4) who conducted ESR measurements on black dust deposited in autopsied human lungs, but no coal miner was included therein. Earlier Retcofsky (2) had examined one lung-tissue sample via ESR spectroscopy and had concluded that the free radicals in the lung tissue reflected simply the fusain (narrow component) ESR signals. The present study was thus undertaken to complement the earlier work (2-4) and the results indicate a positive correlation with the disease severity fairly strongly."

Mar 1, 1989

By K. L. Erickson, Gerald A. Munson

"The need for spodumene as a source of lithia for war purposes led to the exploitation of the Edison pegmatite deposit 1-1/2 miles southeast of Keystone, S. Dak. The operation was conducted during 1943 and 1944 by the Lor Mining Co., Rapid City, S. Dak. Spodumene concentrates in the ratio of 15:1 were recovered by hand picking from a sorting belt. This method was expensive and wasteful of spodumene, owing to the small size of the crystals.Data4/ obtained by the Bureau of Mines indicates that blunging with hydroflouric acid or sodium hydroxide is a prerequisite to selective flotation. Results of tests by Denver Equipment Co., Denver, Colo., indicate that economic recoveries can be obtained in an alkaline circuit after desliming.At the request of the Lor Mining Co., K. L. Erickson, metallurgical engineer, was permitted to work in the pegmatite research laboratory to verify previous investigations and to determine problems that might be involved in commercial milling. The ensuing investigation indicated that electrolytes in the mill water produced a profound inhibiting action on the flotation of Edison spodumone.An investigation of mill water from various sources showed that some waters are suitable for the process and others are not. Subsequent testing showed that all of the available waters are suitable after treatment. The flotation of the Edison spodumene in an alkaline circuit after desliming and using oleic acid as collector is efficient and economical when the water does not contain impurities.In its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B.Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches arc under the supervision of Dr. R. S. Dean, assistant director.As the work was of a practical nature, samples from possible mill-water sources in the southern Black Hills were obtained, and commercial softening and demineralizing methods were investigated. Data on various waters tested are given in table 1."

Jun 1, 1946

By G. S. McCaa

Rock-dusting is an. effective means of preventing coal-dust from propagating an explosion in a coal mine, but it will not prevent gas from igniting-explosively and with much attendant damage locally. Ventilation must therefore be effective at all times, regardless of the employment of other explosion-prevention methods, if gas explosions are to be avoided. This paper describes a gas explosion which occurred in as bituminous mine that was well rock-dusted at the point of ignition and which exemplifies the value of rock-dusting, the necessity of maintaining effective ventilation, and the need of permissible rock-dusting machines receiving power from a permissible locomotive. Description of Explosion The mine in which this explosion occurred is developed on a panel system in a practically level seam; the panel entries are driven in pairs, and the air current intakes on the right entry and returns on the left entry. Near the mouth of the intake a door is placed to control the ventilation; board stoppings are placed in crosscuts, except the second from the face, in which a brattice cloth curtain is hung, the last crosscut is left open and line brattices conduct the air current from the last crosscut to the faces. In No. 7 entry the last cross-cut was 152 feet from the face, the line brattice being within 38 feet of this face, and the second crosscut was 250 feet outby the face of the back entry or return. Seven days prior to the explosion the intake and return entries were rock-dusted to within 38 feet of the face, and as the entry had advanced during the week, the rock-dusting was to be extended.

Jan 1, 1929

By N. A. Eilertsen

Eastern Aroostook County, Maine, contains an enormous tonnage of manganese widely distributed in manganiferous sedimentary beds composed of hematitic shale, hematitic slate, and laminated siliceous carbonate rock. The bedded deposits range in thickness from several feet to over 150 feet. Manganese minerals that occur as silicates and carbonate are so minute that they cannot be concentrated by present methods of ore dressing. From a hydrometallurgical standpoint, the deposits can best be classified by amenability to acid leaching. The deposits of Aroostook County are in three geographical groups (see fig. l), designated as the northern, central, and southern districts. At least 13 deposits are known to occur in the latter district, which covers an Ewes about 8 miles wide and 15 miles long. The Littleton Ridge deposit, on the northern boundary of the southern district, previously examined by geologists from the State and Federal Geological Surveys on the farms of Donald H. Haggerty and David A. Abernethy, was pointed out in reports as being possibly the richest and largest in the southern district. The Bureau of Mines sampled this deposit by surface trenching and diamond drilling from May 1 to September 30, 1951. A total of 23 trenches was bulldozed, aggregating 5,355 linear feet, of which 8 trenches were sampled by cutting 185 channel samples over a linear distance of 1,820 feet.

Jan 1, 1955

By M. L. Wouden

In the late 1970's, the Bureau of Mines began to examine the criteria for reestablishing vegetative cover on coal strip mine spoils near Glenrock, WY. A 9-acre plot, consisting of (1) spoils covered with topsoil, (2) spoils without topsoil, and (3) spoils treated with sewage sludge, was constructed. These plots were seeded with Tegmar intermediate wheatgrass (Agropyron intermedium), Fairway crested wheatgrass (A. cristatum), and Critana thickspike wheatgrass (A. dasystachyum). After 5 yr, the topsoil had about 70 pct plant coverage. Revegetated spoils, without topsoil addition, averaged approximately 30 pct plant coverage, and sewage sludge-treated spoils had about 45 pct plant coverage. Comparison of grass types showed the intermediate wheatgrass produced greater surface coverage.

Jan 1, 1986

By O. C. Blade

The use of Diesel fuel continues to increase. In the United States during 1951 over 120,000,000 barrels of Diesel fuel oil were sold. The railroads used approximately 43.5 percent of this volume; industries such as smelters, mines, and manufacturing plants used about 12 percent; trucks, busses, tractors and bulldozers 20 percent; water craft 14.5 percent; and the remaining 10 percent was consumed by gas and electric utilities, the military forces, and oil companies. These figures were calculated from data issued by the Bureau of Mines. 2/ Complete data for 1952 are not yet available, but it is known that by December 1952 over 13 3/4 million barrels of Diesel fuel per month were produced by the country's refineries and by April 1953 the monthly production had increased to 1 4,333,000 barrels.3/ Information on the properties of this type of engine fuel is very important to the petroleum industry, engine manufacturers, and consumers. To supply this information the American Petroleum Institute and the Bureau of Mines, United States Department of the Interior, under cooperative agreement, are conducting annual surveys of Diesel fuel oil produced in refineries in this country.

Jan 1, 1953

By Thomas M. Barczak

The 1990s brought an unprecedented increase in the development of innovative technologies to provide more effective and easier-to-install roof support in underground mines. To facilitate the application of these technologies in improving mine safety, the National Institute for Occupational Safety and Health (NIOSH) developed the Support Technology Optimization Program (STOP). STOP is a Windows-based software program that provides mine operators with a simple and practical tool to make engineering decisions about the selection and placement of these various roof support technologies. The program includes a complete database of the support characteristics and loading profiles obtained through safety performance testing of these supports at the NIOSH Safety Structures Testing Laboratory. A support design criterion in the form of the required support load density at a specified convergence can be established from four options: (1) a database of measured ground reaction obtained from various mines or ground behavior information input by the user,(2) load requirements based on a detached roof block or rock failure height, (3) criteria based on the current roof support system, and/or (4) arbitrary criteria set by the user. Using these design criteria, the program will determine the installation requirements for a particular support technology that will provide the necessary support load density and convergence control. Optimization routines are also available to determine the most efficient support design for a user-specified support installation. In addition to these performance measures, STOP can be used to compare material handling requirements and installation costs. Comparisons among the various support technologies are easily made, including a graphical analysis of relevant support parameters. This paper describes STOP and its application to optimizing standing secondary roof support systems.

Jan 10, 2000

By Danton L. Paulson

Elevated temperature electrical resistivity measurements were made by the Bureau of Mines on arc-melted, spin-cast, and hot-pressed columbium carbide¬carbon (CbC-C) and zirconium carbide-carbon (ZrC-C) materials up to 2,000° C. The CbC-C materials displayed electrical resistivity values ranging from 35.20 microhm cm at 23° C for hot-pressed material containing 12 wt pct carbon to 242.64 microhm cm at 1,622° C for arc-cast material containing 17.0 wt pct carbon. Electrical resistivity values ranged from 29 microhm cm at 20° C for arc-cast ZrC-C containing 16 wt pct carbon to 279 microhm cm at 1,951° C for hot-pressed ZrC-C containing 21 wt pct carbon. Data from a previous report were included to establish comparison between the electrical resistivities of the CbC-C, ZrC-C, and HfC-C systems.

Jan 1, 1969