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By L. B. Pankratz

Present-day interest in the rare-earth elements and their compounds, for both metallurgical and ceramic uses, makes it highly desirable to accumulate basic thermodynamic data that can be applied to theoretical considerations of the processing of these substances. Such data still are seriously lacking. This Bureau of Mines paper reports the results of high-temperature heat content measurements of the sesquioxides of four rare-earth elements--europium, gadolinium, neodymium, and samarium--and of the closely related element, yttrium. The temperature ranges covered by the measurements are as follows: Monoclinic Eu2O3, 298°-1,802° K. Cubic Eu203, 298°-1,350° K. Monoclinic Gd203, 298-1,802° K. Cubic Gd203, 298°-1,550° K. Hexagonal Nd203, 298°-1,795° K. Monoclinic Sm203 298°-1,798° K. Cubic Sm203, 298°-1,149° K. Cubic Y203, 298°-1,799° K.

Jan 1, 1962

By Lloyd A. Morley, Alan M. Christman

PART A. ELECTRICAL EQUIPMENT – GENERAL Paragraph 1. Electrical Equipment; Examination. All electric equipment shall be examined, tested, and properly main¬tained by a qualified person to assure safe operating conditions. The examinations and tests shall be performed at intervals not exceeding six (6) months unless otherwise specified in Parts A, B, C, D, and E. When a potentially dangerous condition is found on electric equipment, such equipment shall be removed from service until such condition is corrected. A record of such examinations shall be kept and made available to an authorized representative of the Secretary and to the authorized repre¬sentative of the miners in such mine. Each item of major equipment, in¬cluding substations, switchgear, load centers, and so forth except powered hand tools, shall be recorded separately. The record of such examination shall include all dangerous conditions found, corrective action taken, and name of examiner, and shall be signed by the person responsible for main¬taining the equipment in safe operating condition, who shall also be a qualified person. Paragraph 2. Electrical Work; Qualified Personnel. No electrical work shall be performed on electrical distribution circuits or equipment, except by a qualified person or by a person trained to perform electrical work and to maintain electrical equipment under the direct supervision of a qualified person. Disconnecting devices shall be locked out and prominently tagged by the persons who perform such work, except that in cases where locking out is not possible, such devices shall be opened and prominently tagged by such persons. Locks and tags shall be removed only by the persons who installed them or, if such persons are

Jan 1, 1976

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 G. E. Rennick

A siphon-type laboratory airlift well was designed and operated by the Bureau of Mines to study the concurrent flow of air and oil in small-diameter pipes. Glass flowstrings ranging from to 1 inch in diameter and from L4 to 64 feet in length were equipped with various-sized air-entry jets. Liquid holdup volumes were used to correlate vertical-flow data, and empirical equations for computing gas requirements were derived. The effect of flowstring length on flow efficiency, oil- and gas-production rates, and gas-oil ratios was relatively minor at all flowing pressures. Air-jet sizes and flowstring diameters, however, had a marked effect on flow efficiency and oil- and gas-production rates. The small air-jet sizes increased maximum flow efficiency and its associated flowing pressures but decreased oil- and gas-production rates. An increase in flowstring diameter increased maximum flow efficiency with its associated flowing pressure and also increased the production rates of oil and gas.

Jan 1, 1965

By James A. Morgan

FIELD MEASUREMENTS OF NOISE WERE MADE ON THE PERIPHERY OF ENCLOSURES DESIGNED, MANUFACTURED AND INSTALLED BY INDUSTRIAL ACOUSTICS COMPANY, INC. ON THE SECONDARY TACONITE CRUSHER AT THE JACKSON COUNTY IRON COMPANY PLANT IN BLACK RIVER FALLS, WISCONSIN. NOISE REDUCTION ACHIEVED BY THE ENCLOSURES WAS SUFPICIENT TO PERMIT REDUCTION OF CRUSHER ROOM NOISE TO 90 DBA, PROVIDED THAT OTHER SOURCES ARE APPROPRIATELY TREATED AND ACOUSTICAL ABSORPTION IS PROVIDED IN THE CRUSHER ROOM. SECONDARY CRUSHER NOISE WAS REDUCED 10 TO 15 DBA BY THE ENCLOSURES.

Jan 1, 1980

By R. W. Stahl

A survey of firefighting facilities and practices in coal mines conducted by the Bureau of Mines3/ showed such variations in equipment and apparent attitude toward fire protection that a comparison with other industry seemed advisable. Although other industry is confined generally to surface operations and the hazards probably are not as great, the same general methods of extinguishment are employed, so that the cost and protection at least should be comparable. An investigation of industry other than mines revealed a generally greater emphasis placed on fire-combating equipment, fire-brigade training, fire-fighting facility inspection, and fire-hazard elimination, as well as a greater average expenditure for fire protection.

Jan 1, 1959

By A. B. Clayton

The Bumpus Cove area is in Unicoi County, Tenn., about 9 miles south of Jonesboro and 5 miles northwest of Erwin. Iron and lead ores were mined in the Bumpus Cove area before the American Revolution. The production of those metals continued intermittently until 1916. In 1850 this area was the most important producer of iron in the South. In 1911 several carloads of zinc ore was recovered from old dumps and shipped to Missouri smelters. In 1913 systematic mining of zinc ores was begun and continued until 1916. After that year, mining again became sporadic and continued so until discontinued in 1943.

Jan 1, 1949

By G. S. Scott

[The Duretiu of Kinen, as :) pr<r"Yof its :;encr:rL propan clealini: with the causes, behavior, n.ncl tor-trol of o1:t1?;.?cite-mine fires, hns investic:&apos;lte3 I varionr. Te:.nr, for Je tec tin:: iccj.r)ic:~ t he;, tint; :,:.zqdergro-.:rid and of <~e termining the trend of the hen tir..: once -I i&apos;i re j 7 knnm tr, he nrcsc~t.]

Jan 1, 1938

By W. O. Vanderburg

The leasing or tribute system has been an important factor in the development of our metal-mining industry, particularly in the gold and silver mines of the Western States. It has received its widest application in. the early history of many camps and in the last stages of many mines. The system is especially adapted to mining where the ore&apos;s occur in narrow veins or are erratically distributed in small bunches or pockets so that selective mining, hand sorting, screening, or hand cobbing is required to produce shipping or milling-grade ore. The leasing system is also applicable to the development of prospects where the owners are unable or unwilling to assume the risks of searching for ore. The virtue of the system lies in the opportunity it affords miners with little capital to get started; at the same time, it rives owners an opportunity to have their property developed at small cost.

Jan 1, 1934

By John M. Gomes

Two molten salt systems were evaluated as electrolytes for the repetitive recovery of tungsten from tungsten oxide (W03) made by calcining commercial-grade ammonium paratungstate. Using a sodium chloride-sodium fluoride-potassium aluminum tetrafluoride electrolyte at 800° C, 1 pound of 99.8 percent tungsten was recovered for each 2.7 kilowatt-hours of energy consumed. The metal contained 1,100 ppm carbon, was in dendritic masses of spherical grains, and had an apparent bulk density of 5.41 g/cm3. T ngsten of 99.9 percent purity was won from a sodium pyrophosphate-sodium tetraborate-sodium chloride electrolyte at 1,000° C; 6.0 kilowatt-hours of energy was consumed for each pound of metal recovered. The metal contained 120 ppm carbon, was in dendritic masses of hexagonal acicular crystals, and had an apparent bulk density of 7.25 g/cm . Each metallic impurity--aluminum, calcium, copper, iron, nickel, and silicon--in the two tungsten products was 16 ppm or less.

Jan 1, 1966

By George R. McCormick

Because several new and unusual synthetic minerals were found in the system MgO-MgF₂ - SiO2 with Li * , or Nat a similar system with Geo₂ replacing Sio , plus Lit was investigated . In addition to the expected compounds of germanium , Ge - fluor - hectorite and a Ge - fluor- chrysotile were synthesized . Protoamphibole was not observed . Data are given for 69 compositions prepared in the system MgO- MgF₂ - Ge02 at 6.94 percent LiF .

Jan 1, 1964

By H. R. Wells

The Blackbird district, Lemhi County, Idaho, has long been recognized as a potential source of cobalt and copper. However, the comparatively low grade and small size of the known ore bodies, the small demand for cobalt, and. the lack of adequate roads throughout the region precluded extensive exploration of the early discoveries in the area. Recent advances in alloy metallurgy, accentuated by wartime activities, greatly increased the demand for sources of domestic cobalt. Beginning In 1941, engineers of the Bureau of Mines conducted an examination and exploration program in the Blackbird district. This work was supplemented by an exploration program by engineers of the Howe Sound Mining Co., 730 Fifth Ave., New York 19, N.Y.

Jan 1, 1948

By R. L. Grayson, S. S. Peng

"Research has been conducted during the past year on a study to correlate respirable coal mine dust characteristics with worker positions and coal seams. The first characteristic of respirable coal mine dust which has been addressed in the correlation study is respirable dust mass concentration. In fulfillment of this objective, two mines operating in different coal seams have been selected for respirable dust mass sampling on both longwall panels and continuous mining sections. At present, sampling has been completed on the longwall panel operating in the first mine, and one half of the planned sampling has been accomplished on the continuous mining section.The first mine sampled is operating in the Pittsburgh coal seam. The average mining height is approximately 78"" with an average of 8"" of bottom shale being mined. The mine is primarily a longwall mine, and continuous mining machines are used to support the longwall.Figure 1 shows the layout of the longwall panel which was sampled. Intake air is coursed via the track heading up to the headgate area. The air splits at the headgate. Approximately 20,000-30,000 cubic feet of air per minute (CFM) is used to ventilate the longwall face and about 5,000-10,000 CFM is routed down the belt entry. Substantial leakage across the gob was noted during the sampling period. An average of 1800 CFM per 100 feet of face leaked through the shields into the gob from #1 shield to #112 shield. A substantial amount of leakage also occurred between the #1 shield and the solid rib of the headgate development panel. The path of the air used to ventilate the panel is shown with arrows in Figure 1. Direction of air flow was opposite to the coal moving direction on the armored face conveyor.A double-drum ranging shearer is used on the face to cut a 30-inch web of coal. Normal practice is to cut from the tailgate to headgate with the leading drum raised and the tail drum lowered for cutting bottom. After reaching the headgate, the shearer is reversed and both drums are lowered for a clean-up pass. The last 40 feet of face on the tailgate is cut on the clean-up pass.The shearer is equipped with 2 banks of 4 water sprays each and 2 large sprays on the headgate end and 1 bank of 4 sprays on the tailgate end. Additionally, sprays are located above bits on the cutting drums. Actual cutting speed was approximately 14-18 feet per minute, depending on conditions.The cross sectional area for air flow on the face was approximately 60 square feet before a pass was mined and 80 square feet after a pass was mined but before the shields were advanced. The cross sectional area at the shearer was about 35 square feet.The condition of both the tailgate and headgate of the panel was good with no signs of significant roof problems. The roof conditions along the face during the sampling period were variable. At times, as much as 3 feet of drawslate fell from the roof for a span of as much as 40 shields. Generally, however, relatively local areas of falling roof were encoun-tered, usually limited to a 10-20 shield span when appearing.Ten days were spent gathering respirable dust samples on the longwall panel. Mine Safety Appliance (MSA) sampling units equipped with 10-mm nylon cyclones, pre-weighed MSA PVC filters, and constant-flow DuPont pumps were used to obtain thesamples. The pumps were calibrated at a 2 liters-per-minute flow rate. The 10-mm cyclone was selected for classifying total dust into the desired respirable fraction in order to obtain ""legally defined"" respirable dust samples for detailed physical characterization."

Jan 1, 1988

By Robert W. Geehan

"INTRODUCTION A preliminary examination of the Argentena mine was made in 'January 1945 by an engineer of the Bureau, who recommended investigation by diamond drilling. The Bureau conducted a core-drilling project at the mine from April 30 to August 4, 1946. Claims investigated are in sec. 33, T. 24 S., R. 58 E., Mount Diablo base and meridian, in southern Clark County, Nev., about 2.2 miles west of Goodsprings.The Argentena mine has been an intermittent producer of zinc-lead-silver ore since 1926. During the war years, ore was shipped to the Government stock pile at Jean, Nev., and to the International Smelting F. Refining Co.'s smelter at Salt Lake City, Utah. The mine has been shut down at intervals because of lack of a market for mixed oxidized zinc-lead ore.The 12 holes drilled by the Bureau totaled 1902 feet. The program was designed to test for faulted portions of the ore bodies know in the mine and to test favorable areas for similar ore bodies. As a result of this program, one faulted segment of the ore body was found, and it was established that no one was present in a second fault block. Similar blocks remain unexplored in the vicinity of the mine. Two holes drilled in favorable areas several hundred feet from the mine failed to discover new ore bodies."

Jul 1, 1947

By G. S. Scott

[The Duretiu of Kinen, as :) pr<r"Yof its :;encr:rL propan clealini: with the causes, behavior, n.ncl tor-trol of o1:t1?;.?cite-mine fires, hns investic:&apos;lte3 I varionr. Te:.nr, for Je tec tin:: iccj.r)ic:~ t he;, tint; :,:.zqdergro-.:rid and of <~e termining the trend of the hen tir..: once -I i&apos;i re j 7 knnm tr, he nrcsc~t.]

Jan 1, 1938

By Sandip K. Mukherjee

This report presents the results of the economic analysis of several applicable alternatives to increase airflow in four underground coal mines. Pressure-quantity surveys were conducted underground and measurements were also made at the main mine fan(s). The existing ventilation networks were modeled using the modified Penn State ventilation simulator. The applicable alternatives were simulated. Performance data obtained from these simulation runs were utilized to conduct the cost-effectiveness analysis. The costs for each of the alternatives included capital, operating and maintenance costs. These costs were expressed as annual ventilation costs per active section in terms of dollars per elm taking into account the economic life associated with each of the alternatives. The benefits were expressed as increased airflow quantity in the critical sections. A section of this report also deals with comparison of simulator predicted air quantity values against air quantity values measured underground. The computer outputs for each simulation run are presented in Volume II of this report.

Jan 1, 1983

By A. B. Hooker, J. W. Paul

"There was a time when any suggestion that the Davy flame (safety) lamp be discarded, would have evoked unlimited, criticism. However, that time is past.Investigations both here and abroad have shown conclusively that the Davy lamp does not have the necessary factor of safety against ignitions of mine gas, and England, the lost stronghold of the Davy lamp in Europe, has eliminated this lamp and substituted safer types.In the United States there are companies who still use the Davy lamp in spite of all that has been said and published as to the dangers connected with its use.Recently the purchasing agent of an anthracite coal company requested the Department of the Interior, Bureau of Mines, to pass upon the safety of some braise gauzes for use in a shielded Davy lamp. A shielded Davy lamp is an ordinary Davy safety lamp equipped with a circular brass shield that is attached to the lamp posts. This shield extends about one-half way around the gauze and one-half of the gauze height. The main purpose of the shield is to prevent the lamps being extinguished by a sudden increase in the velocity of the air current past the lamp.The brass gauzes submitted for this test represented two grades of brass - a yellow brass and a red brass. The analysis of these brasses was not determined. Two shielded Davy lamps that were submitted for the tests each had a steel gauze. These steel gauzes were also tested. Tests were made in horizontally moving mixtures of Pittsburgh natural gas and air at velocities of 400 to 1,000 feet per minute. The gas percentages used were 7%, 8.6%, and 11%. Tests were made with the lamp shield in two positions relative to the lamp and direction of flow of the gas-and-air mixture. In one position the shield was between the gauze and flow, as normally used. In the other position the shield was on the downstream side of the lamp. The tests were continued until one or more failures or gas explosions been obtained with each of the six gauzes. The results of these tests summarized as follows:"

Jun 1, 1923

By James Noll, Sam Janisko

Underground miners are exposed to some of the highest levels of diesel particulate matter (DPM) in the United States. Therefore, it is important to monitor the exposure of miners to DPM, but it can be difficult because of the complex composition of DPM and the number of interferences. Currently, elemental carbon (EC) is used as a surrogate because it makes up a significant fraction of the DPM and is not affected by interferences. Standard measurement methods for EC can be time consuming and only record end of shift results. In this research, a laser absorption technique that enables one to measure EC concentration in near real time was shown to be a beneficial tool. The real time data showed that the fresh air being drawn into a stone mine was not properly reaching the working area and needed to be redirected to decrease DPM concentrations. The real time data also provided a more accurate efficiency ofan environmental cab compared to just using the standard method by detecting the opening of the cab&apos;s window and door. The EC optical monitor was also worn by researchers in a mine to show how it can give not only the average concentration for the shift but also reveal when and where a miner is exposed to DPM. Keywords: Laser absorption, diesel, elemental carbon, mining, exposure

By C. Gary Reiness

A safety glass eyepiece which had been repeatedly exposed to mine environment over a number of years was studied to determine some of its optical properties. In the regions from 385 to 400 mµ and from 625 to 760 mµ, the transmittance was less than the 89 percent required by the American Standard Safety Code for Head, Eye, and Respiratory Protection. From 200 to 320 mµ the relative transmittance of two parts of the eyepiece was found to vary widely, having a maximum of 38 percent difference at 315 mµ. Irradiation of the glass by ultraviolet light caused enhanced absorption in the range from 200 to 1,200 mµ. There was a time-dependent increase of 1016 color centers per cubic centimeter throughout this range after 36.5 hours of irradiation. The rate-of-growth curve for the optical density, at 243.5 mµ and 23° C, was resolved into linear and saturable components, indicating zero order and first order

Jan 1, 1968

By F. Sillers, R. T. C. Rasmussen

"INTRODUCTION This is the fourth report of investigations dealing with the cooperative tests between the Bureau of Mines and industry on the use of electrolytic manganese in steelmaking. The first report dealt with the use of electrolytic manganese in the manufacture of stainless steel 3/ the second with its use in acid electric steel practice, 4/ and the third with its use in low-carbon basic open-hearth steelmaking. 2/ A résumé of those investigations E7 appeared in the magazine STEEL. 5/ The present report deals with the use of electrolytic manganese in the manufacture of four types of stainless steel and the new Timken 16-25-6 alloy. The Bureau of Mines supplied The Timken Roller Bearing Co. with 62,000 pounds of electrolytic manganese for use in the tests.The electrolytic manganese was produced at the Bureau of Mines pilot plant, Boulder City, Nev., by the process developed by the Bureau and described in Bulletin 463, Operation of Electrolytic Manganese Pilot Plant, Boulder City, Nev., by J. H. Jacobs. J. W. Hunter, W. H. Yarroll, P. E. Churchward, R. G. Knickerbocker, R. W. Lewis, H.A. Heller, and J. H. Linck. The workcarried out under the direction of R. S. Dean, formerly assistant director, Bureau of Mines, and R. G. Knickerbocker, formerly chief, metallurgical branch, as part of a long-range program involving the development, manufacture, and use of manganese from domestic ores. Preliminary arrangements for the plant tests were made by the late A. A. Dow. 7/"

Jun 1, 1947