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By T. SPOLAN, G. W. Jones, R. E. Kennedy

Information relative to the explosibility of acetylene at elevated pressures and means of handling acetylene safely under these conditions is of considerable interest at present. American practice limits the pressure at which acetylene may be generated and distributed to poiIits of' use. The pressure in portable acetylene generators is 15 pounds per square inch gage. Tests made by the Bureau of Mines have shown that 15 pounds per square inch gage is too high to prevent explosiofiS of gaseous acetylene in the absence of air; in fact, dry acetylene gai can be exploded at pressures greater than 5.9 pounds per square inch gage. The Bureau has been interested in the explosibility of acetylene for many years because of its continued: use for illumination in many metal mines and its general use in cutting 1illd~--eldifigoperations in the mining maus-try.

Dec 1, 1948

By A. B. Hooker, R. A. Kearns

Material used for flame safety lamp gauzes should possess the following qualities: (1) mechanical strength, (2) resistance to corrosion under service con- ditions, (3) a relatively high thermal conductivity, (4) a melting point above the ignition temperature of mine gas. Heretofore, three metals have been used for flame lamp gauzes, namely: steel, brass and copper. While each of these has the requisite qualities to some extent, none of them is an ideal gauze material. Copper gauzes lack mechanical strength, especiall, after they have been heated; brass and copper both have comparatively low melting points so that before the gas ignition is reached the gauze metal is attacked and oxidized under the action of the heat. Steel corrodes readily in damp atmos- pheres and if the lamp stands unused under these conditions for some time, the gauzes become unfit for service. Tests of these three materials have shown that steel offers the highest degree of safety. Manel metal, the natural alloy of nickel and copper, is practically noncor- rodible. Its relting point is approximately the same as that of steel. From time to time it has been suggested that this alloy might be a better gauze material than steel, since gauzes made of Monel metal should have all of the good qualities that steel gauzes possess and, in addition, would not corrode appreciably in ordinary mine atmospheres. One advocate of this use for Monel metal, the International Nickel Co., through their development engineer, Mr. Robert J. McKay, cooperated with the Interior Department, Bureau of ines, to the extent of supplying twelve sets of 30 mesh, Monel-metal gauzes for tests. Those gauzes were made up by the same lamp manufactur- er ho rade the steel gauzes used in the previous investigation. Being made by the same processes as the steel gauzes, these Manel-metal gauzes were needlessly given the same anti-rust coating that is always applied to steel gauzes to prevent any corrosion before the gauzes are used. In previous tests the Bureau of Mines had collected data as to the behavior of steel gauzes. In determining the value of Monel metal as a gauze material, it was planned to obtain similar data with Monel-metal gauzes, and thus make a direct comparison with the steel gauzes. In addition, steel and Monel-metal gauzes

Apr 1, 1923

By Robert W. Geehan

The Bureau of Mines has been developing deposits of critical and essential minerals in the United States since 1939. A preliminary examination of the Union lead mine was made in November 1944 and January 1945 by W. T. Benson, a Bureau of Mines engineer, who recommended development by diamond drilling. The Bureau conducted a drilling project at the mine from February 12 to May 16, 1947. The property is in sec.12, T. 17'N., R. 19 E., Mount Diablo Base and Meridian, in. southern Washoe County, Nev., about 15 miles south of Reno. The Union lead mane, also known 4s the Commonwealth mine, has been an intermittent producer of zinc-lead-silver ore since 1860. During World War II, ore was shipped to smelter& near: salt Lake City, Utah. The Bureau drilled 21 diamond-drill holes having a total length of 1,549 feet and 20 long percussion-drill holes with a total length of 359 feet. The program was designed to test for horizontal and vertical extensions of the ore body and to prospect for parallel ore bodies. As a result of this program, extensions of the ore zone were established, but no parallel ore-bearing structures were found. The areas drilled were limited by drill sites available.

Jan 1, 1950

By M. J. Ferrante

The Bureau of Mines recovered rhenium powder from scrap tungsten alloy containing approximately 25 percent rhenium. Oxidation of the scrap at 950° C separated volatile rhenium heptoxide from tungsten trioxide. Minor amounts of tungsten, iron, and nickel were removed by selective precipitation from a rhenium solution from which was recovered crystalline ammonium perrhenate. Experimentation showed that hydrogen reduction of minus 325-mesh ammonium perrhenate at 1,000° C produced rhenium powder averaging 2.1 microns in size (Fisher Sub-Sieve method). The powder contained <50 ppm of total metallic impurities and 1,070 ppm of total interstitial impurities. Sintered compacts had a density of 95 percent of theoretical. Approximately 96 percent of the rhenium contained in the scrap alloy was recovered.

Jan 1, 1969

By R. B. Prater

The Bureau of Mines conducted research to separate the F from byproduct Zn concentrates obtained from fluorspar (CaF2) production, as part of the Bureau&apos;s effort to devise efficient, environmentally acceptable technology for recovering Zn from resources considered undesirable by Zn producers. Sulfuric acid (H2SO4) was found to be effective in F removal, while ammonium carbonate [(NH4)2C031 was not. The most important variables for reducing the necessary residence time were found to be temperature and agitation. Optimum leaching conditions were 75° C and 500 r/min for 2 h at 40 pct solids with 0.2 g acid per gram of concentrate, which resulted in a 98.3-pct F extraction. Zinc losses during F removal were in the range of 2 to 3.3 pct. Other elements such as Fe, Cd, Ca, and Cu were also partially dissolved. About 93 pct of the F was removed from the leach solution by neutralization and precipitation with calcium hydroxide [Ca(OH)2]. Additional treatment might be necessary to limit the buildup of soluble elements in the recycled leach solution.

Jan 1, 1985

By Roger J. Morrell

Disk-cutter experiments were performed on five rock types ranging in compressive strength from 9,000 psi to 27,000 psi. A specially constructed testing machine called a linear-cutter apparatus (LCA) was designed to load and traverse a free-rolling disk cutter across a sawed rock surface. The LCA was instrumented to measure the vertical and horizontal forces acting on the cutter during the run.. The ability of disk cutters to fragment rock was determined for both 60--degree and 90-degree cutting-edge angles, and relationships and regression equations were developed to predict cutter performance based on rock physical properties and applied forces,

Jan 1, 1970

By J. A. Herdlick

At the request of the War Production Board a preliminary examination of the Big Ben molybdenum prospect near Neihart, Cascade County, Mont., was made by the Bureau of Mines under G. N. Bennett, mining engineer, Bureau of Mines Montana district office, in September 1942. Formal investigation, consisting of sampling, core drilling, and metallurgical testing, was later undertaken and completed in 1943. Field work was directed by Robert D. O&apos;Brien, mining engineer, Montana district office, under the supervision of E. W. Newman, supervising engineer, Montana district office. This report describes the deposit, presents the factual data obtained from the sampling and core-drilling operations, and summarizes the results of the metallurgical studies. The deposit was first located and prospected in 1922 by the present owner, Frank Mansikka of Neihart, Mont. Periodic examinations made by responsible mining interests were culminated in 1938 when the Federal Mining & Smelting Co. optioned and investigated the property. No ores have been produced from the deposit to date.

Jan 1, 1949

By L. C. IlsLey, H. B. Freeman

In connection with the approval of coal-cutting machines for service in gaseous mines , the engineers of the Bureau of Mines have been somewhat concerned as to the type of trailing cables that could safely be used on permissible outfits . While no final action has been taken on this question ( tentative approvals having been granted pending investigations ) , the Bureau has been endeavoring to collect data and information on this question which would permit a fair , yet safe , ruling to be made . For this purpose cooperative arrangements were made with three coal companies to visit certain of their mines , making inspections inside the mines to observe the cables and cutting machines in operation . In all , twenty mines were visited . A questionnaire covering the operations of trailing cables was filled out at each of these mines . In a few instances no personal inspection was made , the information being supplied by mine officials after conferences with the Bureau's engineer . At other mines the information given by mine officials was supplemented by personal observation inside the mines , usually at a time when the cutting machines were in operation .

Jul 1, 1923

By G. W. Jones, I. Spolan

"INTRODUCTION The operation of internal-combustion engines at high altitudes and the general aspects of combustion processes in rarefied atmospheres have created considerable interest in the problem of ignition and flame propagation at low pressures. Nuckolls, Matson, and Dufour 4/ have published results on the effect of low pressures on the propagation of flame in gasoline vapor-air mixtures in vessels of large capacity. The volumes of their test equipment varied in capacity from 0.425 to 125 cubic feet. Various sources of ignition were employed. These authors found that the explosive range of gasoline vapor in air decreases with decreasing pressure at pressures considerably below atmospheric, until a limiting absolute pressure of about 33 mm. mercury at ordinary temperature is reached, at which point no appreciable flame is propagated.Experiments carried out at the Bureau with natural gas-air mixtures at reduced pressures have shown 5/ that the limits of inflammability are but little affected at reduced pressures down to 175 mm. mercury. As the pressures of natural gas-air mixtures are reduced below atmospheric, the mixtures become more difficult to ignite; however, if a suitable source of ignition is employed, the limits of inflammability are as wide at 175 mm. mercury absolute pressure as they are at atmospheric pressure. In view of these observations with natural gas-air mixtures, it appears important to investigate gasoline vapor-air mixtures for possible similar behavior. For this reason the tests herein described were carried-out."

Oct 1, 1946

By John C. Machisak

THIS INFORMATION CIRCULAR covers the calendar year 1055 and contains statistical data on employment and injuries pertinent to metal and nonmetal mining and to their mills and processing plants that are voluntarily reported annually to the Federal Bureau of Mmes. This report, unlike previous publications, lists not only production and development workers but also office employees associated with mining and milling or processing. The last publication m the series, Information Circular 7798, Injury Experience in the Metal and Nonmetal Industries, 1954, also contains unpublished injury and employment statistics for 1943 through 1953. The Bureau is authorized to request data on injuries and employment from operators in the metal- and nonmetal-mining industries. The information voluntarily submitted by these operators contributes immeasurably to the promotion of safety in the mineral mining industries as it discloses the hazards to which metal and nonmetal workers are continually exposed during mineral extractive operations.

Jan 1, 1959

By E. P. Youngman

In this island, which is a Crown colony of the British Empire, and where remarkably extensive remains of ancient mining operations-- mainly for copper--exist, the mining law of Turkey governs, rith such modifications as were made necessary by the transfer of the country in 1878 from Turkey to Great Britain, and with such fer ameliorations thereof as have since been ordered by the local authorities. The Turkish law to which Van agenen refers is, no doubt, "2 Shaban, 1285," which though subsequently repealed with respect to Turkey is still in force in Cyprus, inasmuch as the mines regulations (amendment) law of 1925 "is to be read in connection with 2 Shaban, 1285" (articles 61 to 67 of which were repealed by the law of 1925): In the preparation of this digest; access was had to the mines regula- tions (amendment) Iaw, No. 5 of 1882; which Van Wagenen does not mention. Other Cyprian laws, passed since the publication of Van Wagenen's work in 1918, are the following: Eines regulations (amendment) law, 1925, No. 12 of 1925; mining-prospecting permits; notification, No. 539 of 1927; mines regu- lations 1926, No. 1006 of 1926; mines regulations (amendment) rules of court, 1926, No. 144 of 1926; mines regulations (amendment). 1a, 1928, ko. 3 of 1528 (as amended by No. 32 of 1928). Most of these làrs are concerned with the regulation of actual mining operation--safety and sanitary provisions; and, therefore, they ado little important information. The Cyprian Government's official publication says: It is considered that the laws regulating mining in Cyprus are inadequate and antiquated, and a thorough revision is necessary to bring them up to a standard of modern mining practice and to encourage mining ventures in the island. As a preliminary to this the mines regulations, 1926, were issued to govern the workings of the larger mines; and serious attention is now being given to the regulating of prospecting, quarries, machinery in mines, and generally to the bringing of mining in Cyprus into conformity with the other mining countries of the world.

Jan 1, 1933

By Albert W. Deurbrouck

Twelve samples from six Barbour County coal beds were analyzed for this report. The samples collected were generally high sulfur content coals, frequently exceeding 3 percent in the raw-coal sample. Many of them could not be upgraded to acceptable metallurgical standards even by rigorous preparation procedures. The production of coal in the county in 1963 amounted to almost 3 million tons of which 44 percent was mechanically cleaned.

Jan 1, 1965

By E. C. Tarpley, H. M. Cooper, R. F. Abernethy

"INTRODUCTION The determination of moisture in coal is an empirical test, because the time, temperature, and equipment are specified. The essential features of the equipment, and details of the procedure are given in A.S.T.M. Designation: D271-44 5/. According to the specifications, the following features should be incorporated in the equipment used:1. Oven must have uniform temperature in all parts.2. Oven must be constructed with minimum of air space.3. Oven must have means of changing the air two to four times per minute.4. Air must be dried over sulfuric acid (sp. gr. 1.84).The analytical procedures governing most of the nation's coal purchases are those given in A.S.T.M. Standards referred to above. These standards are general and of such scope as to cover all ranks and types of coal. In cases where only the moisture is required, a faster method than the standard procedure is desired.The semi-automatic moisture tester manufactured by the Brabender Corp. has proved itself in many industrial processes where the rapid estimation of moisture is of vital importance. With the approval of A. C. Fieldner, chairman, A.S.T.M. Committee D-5, and through the courtesy of Lowell Malan, chief chemist, United Electric Coal Companies, who loaned the tester, tests were made to determine the feasibility of using this instrument to determine the moisture in coal."

Jun 1, 1948

By M. K. Quinn, N. P. Reddy, A. W. Khair

"An analysis of coal fragmentation due to the action of a continuous miner is presented. Underground coal cutting by a drum-type continuous miner was simulated in the laboratory using a specially designed unique automated rotary coal cutting simulator (ARCCS). The rotary coal cutter provided the versatility of varying the operating and in-situ parameters to provide information on the effects of generating 37 pm (0.0015 in) particles. In these tests, coal blocks with an approximate dimension of 50.8 x 35.6x 20.32 cm (20x 15x 8 in) were first subjected to confining pressures equivalent to in-situ conditions. The blocks were then cut by the rotary cutting head of the ARCCS, thus simulating the action of the continuous miner in underground coal mining. During the tests under a particular set of in-situ and operating parameters a number of other parameters such as (1) penetration of bit into coal, (2) penetration resistance (thrust and cutting pressures), (3) rotating velocity of' cutting head, and (4) acoustic emission activity in the coal block were monitored. During the test, all the cut products were collected for size distribution analysis. After each cutting cycle the fractured surfaces were photographed and a velocity survey was conducted using a sonic technique. At the end of each experiment the cutting paths of the bits in coal were photographed using a camera attached to an optical microscope.The results led to a better understanding of the mechanisms of the fragmentation process during coal cutting and the effect of operating parameters, in-situ conditions and coal type on the size distribution of the cut product:"

Jan 1, 1989

By X. B. Starnes

"INTRODUCTION The Eva Tanguay property is in Crittenden County, Kentucky, about 1 mile south or the village of Mexico, and can be reached from Marion, the County seat, by travellng south on State Highway 91 for 6.8 miles and then turning southwest on State Highway 70 and traveling 2 miles farther.Although the property lies between the Huffaw and Pigmy properties, which together have produced 200,000 tons of fluorspar ore, production from the Eva Tanguay has been estimed at only 1,000 tons. Geological factors on the property indicated the likelihood of an ore occurrence, and the author examined the property in April 1944. Shortly thereafter, the U.S. Geological Survey wrote a report on the property, which was not published. A drilling program was initiated by the Bureau of Mines November 1, 1944, and continued until eight holes totaling 3,137.5 feet were drilled.The holes showed that the Tubb fault system on the Eva Tanguay property is composed of three members, all of which contained commercial ore. The line dividing the Haffaw and Tanguay properties crosses the vein outcrops, causing a part of the ore indicated to be on each property.The mineral rights, which are leased by Robert Frazer of Marion, are owned by Mrs. O. S. Denny and W. C. Bohn, both of Marion."

May 1, 1947

By Wing G. Agnew, Paul L. Russell

"INTRODUCTION During the past few years, the development of millisecond-delay electric blasting caps has made possible a more flexible control over timing the firing of individual charges in blasting, The use of these caps has proved especially productive in quarry blasting and in numerous construction operations, but their use in underground mining is developing more slowly, although in some cases, as the solution to a difficult breaking problem, they have been well-received. When used in metal-mine drifts, the general objection is that the broken rock is thrown too far. In nearly all cases, however, use of millisecond-delay caps results in better fragmentation of the rock and a lower powder consumption per ton of rock broken.Prom 1949 to 1952, several series of experiments were conducted at the Mount Weather, Va., Experimental mine in conjunction with driving a 6- by 10-toot ventilation raise. 3/4/ The raise-round experiments in this 238-foot shaft, using millisecond-delay electric blasting caps in various drill-round patterns, are the subject of this report.SUMMARY AND CONCLUSIONSAll rounds discussed in this report were drilled in the hard rock (epidosite and greenstone) of the ventilation raise at Mount Weather Experimental mine (figs. 1 and 2). The drill-round patterns varied from 28- to 32 holes and from a V-cut design to one having no cut boles at all. With the exception of the first two rounds, all blasting was done with millisecond-delay electric blasting caps. In all rounds 60-percent ammonia gelatin dynamite was used and holes were stemmed with two cartridges of sand stemming."

Apr 1, 1953

By J. J. Shields

This is the Seventh of a series of publications that describe methods and practices used in mining bituminous coal mechanically.3/ This report deals with the operation referred to in coal mining as continuous mining, and the interest shown by mining companies in this method is the reason for this study. Only continuous mining as it applies to the room-and-pillar system of mining, or a modification thereon, is discussed in detail in this report. Although not always as continuous as the name implies, it is a system of mining in which a machine is used to cut and load coal in one continuous operation without drilling and blasting the coal. With the mining equipment in most general use today, the usual cycle of operation in mining of coal is: (1) Timber, (2) cut, (3) drill, (4) blast, and (5) load. As the phases of this type cycle cannot be performed simultaneously in the same working place, it is necessary to operate from 3 to 7 working places so that at least 1 place is available for coal loading at all times. Even if the schedule of the phases in a cycle is maintained, coal production ceases during the time required to move the loading equipment from one loading place to the next. In 1920 a continuous-type mining machine4/ was installed in an Illinois coal mine to drive entries. Several other companies used these entry drivers for short periods in the following few years. In 1927 a southern Illinois coal company installed 2 of these machines which, in the next 25 years, were reported to have driven over 200 miles of entries. The machines did not attain widespread usage.

Jan 1, 1954

By L. K. Weaver

The objective of this Bureau of Mines publication Is to present a nomograph that provides a fast, convenient method for estimating hydrocarbon lease bonus bids for offshore acreage in the Gulf of Mexico. Discounted cash flow analyses were computed from a model derived to show the costs necessary to explore, acquire, develop, produce, and abandon a 5,000-acre block of offshore acreage, and the estimated income from the sale of the hydrocarbons produced from the block. The range of the variables in the financial analyses used to construct the nomograph are prices of oil, $2.50 to $5.00; recoverable hydrocarbon reserves, 44,651,476 to 127,575,645 barrels; and discounted cash flow (DCF) rates of return, 5.0 to 57.2 percent. A total of 1,234 sets of DCF data were used to construct the nomograph. The range of bonus bids shown on the nomograph is from 2 to 90 million dollars ($400 to $18,000 per acre).

Jan 1, 1973

By W. W. Adams, T. D. Lawrence

"The National Safety Competition covering the calendar year 1934 was the tenth yearly safety contest conducted by the United States Bureau of Mines. Participating in the competition were 334 mines and quarries in 38 States. Five mining or quarrying companies, each the leader in its group for having established the best safety record during the year, were awarded the national safety trophies ""Sentinels of Safety.""Since these annual contests were begun 10 years ago by the United States Bureau of Mines the scope of the competition has been broadened materially, both as to the number of plants participating and as to the number of man-hours of exposure to accident hazards. Moreover, marked progress in the prevention of accidents has been achieved, as is indicated by an almost constant downward course in toe accident-frequency rates for the contest group as a whole during the past 10 years. On the other hand, the accident-severity rates for the group showed an upward trend during the first part of the decade and a downward trend during the latter part of the period except in 1930 and 1934; in each of those years a disastrous explosion with abnormally heavy loss of life occurred at the property of one of the participating companies.Because of the abnormal nature of the major disaster in a bituminous-coal mine in 1930 and 1934 the accident-severity rates for the bituminous group for those years are not strictly comparable with the rates for other years. The rates for bituminous mines for 1934 in the present report have therefore been computed on two bases; first, to exclude the record of the company that suffered the disastrous explosion and, second, to include the record of this company. The first rate represents the normal experience of the bituminous coal companies unaffected by the disaster and is therefore more indicative of the real trend of the accident rates for this class of mines from year to year. The latter rate shows the actual experience of all bituminous mines in 1934. The report of the competition of 1930 likewise showed the rates for the bituminous group as computed both with and without the disaster that occurred that year.The National Safety Competition is conducted by the United States Bureau of Mines in the interest of safety in the mining and quarrying industries. This object is accomplished directly through the efforts of the competing companies and their employees to win first place in the competition and thereupon receive well-merited and national recognition for their achievement. Indirectly the purpose of the contest is accomplished through studies by the Bureau of Mines of the facts contained in the accident reports which the competing companies furnish to the Bureau to enable the Bureau to compute the accident rates that are the basis for determining the winners of the contest."

Jun 1, 1935

By Joe B. Rosenbaum

New applications and concepts of solvent extraction as a unit operation in extractive metallurgy have been developed in the last decade. Wider use is being made of established solvent extraction techniques in processing spent nuclear fuel elements and in winning columbium-tantalum, hafnium-zirconium, thorium, tungsten, uranium, and vanadium. Commercial application has been extended to recovery of beryllium, boron, bromine, copper, molybdenum, phosphorus, rare-earth metals, and rhenium. Systems in use and proposed typically extract metals or salts as anion, cation, or neutral species from aqueous media by reaction with a recycleable organic reagent.

Jan 1, 1971