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By J. R. Thoenen

Profits in the crushed-stone industry, as in any other, represent the difference between selling price and production cost. When consumer demand increases rapidly, as occurred in the crushed-stone industry from 1918 to 1927, selling prices tend to rise. Cost of production usually rises, also, owing to the expense of expanding facilities, searching for and developing new quarries, and purchasing, installing, and operating new equipment. Frequently, also, the inattention of managements to the details of operating costs is responsible for their increase. This is not due to negligence but rather to the necessity of confining attention to the problems involved in producing material to supply orders. When market conditions change and consumer demand becomes stabilized or contracts, the producer r s attention usually is directed to assuring the orders necessary to keep his enlarged facilities busy. Hence, competition increases and soiling prices decline.

Jan 1, 1939

By H. P. Greenwald

Cooperation between the Bureau of Mines of the United States Department of the Interior and the Safety in Mines Research Board of Great Britain dates from 1924. It has been intimate and has involved exchange of personnel and. equipment as well as information. Correlation of divergent results obtained in large-scale tests of the explosibility3/ of coal dusts made in the respective countries was one of the first problems to be studied. The purpose of this paper is to show to what extent such correlation has been achieved. COMPARISON OF TEST METHODS The first research accomplished Jointly by the two organizations was a comparison of large-scale methods of determining the explosibility of coal dust. Large samples of coal were exchanged and subjected to test in the Bureau's Experimental coal mine and in the Board's steel gallery, 38 inches

Jan 1, 1939

By S. L. Gerhard

In the United States the performance characteristics of permissible explosives are controlled by routine tests, which include firing the explosive into a gallery filled with a methane-air mixture. These tests are made by the staff-of the Explosives Division of the Bureau of Mines and are similar, in general, to those employed in other countries. This control has helped to reduce the frequency of accidents involving the ignition of firedamp by explosives but has not clarified the basic causes of the ignition. To advance this control and to minimize potential hazards further, this fundamental knowledge is needed. Some of the results of recent research on the causes of the ignition are described herein. NATURE OF THE PROBLEM When an explosive ignites firedamp in the gallery tests, the source of the ignition must be one or more of the emissions from the steel borehole. It has been accepted generally that these emissions are (1) particles, (2) the shock wave, and (3) hot gases and flames. Photographs show that the shock wave emerges from the borehole first, followed closely by hot gases. At first the velocities of these are high and approximately equal, but the velocity of the gases decreases more rapidly than that of the shock wave, and by the time the reactions causing the flame are complete the shock wave travels in an otherwise undisturbed medium. The particles are originally enveloped in the hot gases but some soon begin to break through and eventually out-distance the shock wave. The approximate geometry of these emissions about 1 millisecond after the shot is fired is illustrated in figure

Jan 1, 1939

By J. J. Forbes

Investigations by the Bureau of Mines and by mining-research departments of European countries have established definitely the value of rock-dusting to prevent or limit the propagation of coal-mine explosions. Its effectiveness in this connection has been demonstrated not only by research but by actual coal-mine explosions in which hundreds of lives have been saved because of its presence. In a general way this paper gives pertinent facts concerning rock dusting practices in the United States. Information has been obtained from many reliable sources, and various coal-mining companies have furnished data on cost and other details.

Jan 1, 1939

By C. F. McCarroll

The effectiveness of an industry?s safety activities can be gaged best by the accident records of that industry. In an effort to gage conditions in the petroleum industry, and with the objective of helping to reduce the number of accidents in it, the Bureau of Mines from time to time has tabulated, analyzed, and published pertinent statistical information3/. These reports have dealt with distribution, causes, and costs and related phases of accidents for various and collective divisions of the petroleum industry in several sections of the country. This type of study aids the personnel of the Bureau in planning the course of its activities in accident-prevention work and gives useful data to persons engaged or interested in the promotion of safety in the petroleum industry, which will aid them in their efforts to reduce the number and severity of accidents. A majority of petroleum operators and ?service" contractors have acknowledged their responsibility to provide their employees with safe working conditions and to their stockholders for greater economic value of invested capital by establishing safety divisions within their respective organizations. Such divisions have a primary duty, namely, to see that properly designed and guarded machinery and working equipment are furnished the employees and that they are trained in the safest practical methods of performing their work. Some companies and individual operators, however, have shown little or

Jan 1, 1939

Significance of the body of iron oxide, which in part overlies as its hanging-wall the rich chalcocite ore-body at Mount Oxide, Queensland, has been variously interpreted by engineers and geologists who have inspected the deposit.Among the interpretations offered is the one that the body represents the residual of an original medium to low grade...

Jan 1, 1939

By Frank L. Hess

In the first cart of that little space of time that we have designated as the nineteenth century, chemistry had reached a wonderful stride. Viewed from the present heights attained by the efforts of innumerable chemists with perfected apparatus, mire reagents, air under pressure, water, gas, and electricity conducted to the desk, and. numberless other helps, it seems marvelous that chemists of that day obtained such results. In 1820, about half of the elements had. been discovered; of these discoveries, Swedes had made 15 or more, about once-third of the elements then known and nearly half of those discovered after 1700.

Jan 1, 1939

By O. C. Blade

In its general study of crude petroleum, the Bureau of Mines has published several reports that include analyses of samples of crude petroleum from Oklahoma fields3/. This report discusses briefly the properties of crude oil samples collects in come of the major producing Yields in the State. ACKNOWLEDGMENTS This investigation was conducted by the Bureau of Mines in cooperation with the State of Oklahoma. The study was via e under the general supervision of R. A Cattell, chief engineer, petroleum and Natural-Gas Division, Bureau of Mines, Whishington, D. C., and N. A. C. Pith, supervising engineer, Petroleum Experiment Station, Bureau of Mines, Bartlesville, Okla., and. Under the direct supervision of Ludwig Schmidt, senior petroleum engineer, Bureau of Mines, Bartlesville, Okla.

Jan 1, 1939

By Wilbert J. Huff

The organization of the Explosives Division has been outlined in two preceding publications.3/ The activities of the various units for the fiscal year 1939 are described hereafter: I. INFLAMMABILITY OF GASES AND VAPORS DETERMINATION OF EXPLOSION HAZARDS OF COMBUSTIBLE GASES AND VAPORS IN MINES AND INDUSTRIES (a) Determination of Limits of Inflammability of Gases and Vapors The following hitherto unpublished limits of inflammability were determined during the past fiscal year.

Jan 1, 1939

By B. W. Gandrud

This report presents the data of one of a series of investigations of the washability of Alabama coals as indicated by float-and-sink tests made by the Bureau of Mines at the Southern Experiment Station in cooperation with the University of Alabama and Alabama coal producers The Klondyke mine, operated by the Blocton Mining Co., is about 1 mile east of West Blocton, Bibb County, Ala., near the southwestern extremity of the Cahaba coal field. The Bureau of Mines already has published three reports that deal with the washability of Cahaba coals - one a washability study of the Clark bed at Marvel4/, one on the tabling of fine coal from the Thompson and Woodstock bed , and the third a washablility study of the Henry Ellen bed at Acmar6/.

Jan 1, 1939

By Blott S. F

The smelting plant and equipment at Mount Isa, as originally designed and built, was described by J. M. Callow (1) *.F. A. Forward (2) described alterations and additions to the plant and discussed the metallurgy of mixed carbonate-sulphide concentrates at Mount Isa, prior to 1933, in the Proceedings of this Institute.In 1933, A. F. McAskill (3) gave full mechanical details of the plant in a paper presented to the Institution of Engineers, Aust.FLOW SHEETSFig. No. 1 represents the present general flow sheet. Forward's (2) flow sheet is reproduced here as Fig. lA, and will serve for comparison in depicting subsequent deletions from, and alterations and additions to, the plant.Fig. No. 2 presents the daily tonnage flow sheet of 1939 practice.ALTERATIONS SINCE 1933General. Many changes in metallurgy and operation have taken place, particularly subsequent to March, 1935, when the treatment of a mixture of carbonate and sulphide ores was discontinued and the mill commenced operating on all-sulphide ore. This alteration brought about the elimination of gravity concentration-Jigs and Tables and resulted in the production of all-floatation concentrates of a very fine sizing. Refer Table No. 2, page?) Radical changes in the analyses and physical nature of concentrates also followed (see Table Nos. 1 & 2, page ?) and, similarly, radical changes in the smelting plant have been slowly brought about.

Jan 1, 1939

By G. W. Jones

During the course of an investigation by the Bureau of Mines into the causes, behavior, and control of anthracite-mine fires, it was observed that the carbon monoxide disappeared from a sealed fire area much more rapidly than could be explained on the basis of leakage of gases. Two suggestions were offered for this high rate of disappearance: (1) That the carbon monoxide, was oxidized at temperatures below 150° C. by either the anthracite or its ash (tests on many anthracites have shown that at temperatures above 150° C. carbon monoxide is liberated in the oxidation products when air is passed through it); (2) that the carbon monoxide was oxidized by micro-organisms present in the sealed area.

Jan 1, 1939

By B. W. Gandrud

[This report presents the data of one of a series of investigations of the washability of Alabama coals as indicated by float-and-sink tests mode by the Bureau of Fines at the Southern Experiment Station in cooperation with the University of Alabama and Alabama coal producers. The Klandyke mine, operated by the Blocton Mining Co., is about 1 mile eat of Vest Blocton, Bibb County, Ala., floor the southwestern, extremity of the Cahaba coal field. The Bureau of Mines already has published three reports that deal with the, washability of Cahaba coals - one a washability study of the Clark bed at Marvel4/ one on the tabling of fine coal from the Thompson and Woodstock beds5/, and the third a washability study of the Henry Ellen bed at Acmar6/.]

Jan 1, 1939

By G. W. Jones

As a part of its general safety program the Bureau of Mines has investigated various means useful for the elimination or mitigation of the explosion hazards in connection with combustible gases incident to the mining industry. Information has been obtained relative to the explosibility of numerous simple and complex gaseous combustible atmospheres. Although experiments along this line have pertained largely to combustible gases in the mining and allied industry, considerable information has been obtained relative to the explosive hazards of combustible gases and vapors used as anesthetics.

Jan 1, 1939

By Albert L. Toenges

A phase in strip mining of bituminous coal is the overturning of the surface of the land. The ;purpose of this report is to acquaint the operators and others interested in stripping with the work that has been done in certain States to reclaim the surface of land from which the coal has been removed by this method of mining. The preparation of this manuscript follows an extensive study of the subject in the field in the course of which a large number of strip mines were visited. ACKNOWLEDGMENTS The information used in the report was obtained through the courtesy and cooperation of the operators of the mines visited, State officials and educational institutions, and others interested in the subject.

Jan 1, 1939

By J. J. Forbes

Investigations by the Bureau of Mines and by mining-research departments of European countries have established definitely the value of rock-dusting to prevent or limit the propagation of coal-mine explosions. Its effectiveness in this connection has been demonstrated not only by research but by actual coal-mine explosions in which hundreds of lives have been saved because of its presence. In a general way this paper gives pertinent facts concerning rock-dusting practices in the United States. Information has been obtained from many reliable sources, and various coal-mining companies have furnished data on cost and other details.

Jan 1, 1939

By Walter English

THE four papers making up this symposum have been prepared espe-cially for those who have no knowledge of seismograph prospecting. To many people mathematics is a formidable subject, and many are discouraged from studying seismograph prospecting under the mistaken assumption that the mathematical requirements are severe. In the papers presented here there is not a single mathematical equation. We believe that considerable competence in dealing with some of the most important problems of this work can be attained without any mathe-matical training whatever. At the present time, there is a real need for interpretation of results by persons thoroughly competent to bring geologic experience and imagination to bear on data that are subject to multiple interpretation from a strictly physical viewpoint. Likewise, those charged with the responsibility of planning seismo-graph exploration campaigns would do well to become familiar with as much as possible of the technical aspects of the work. They would then be in better position to judge of its success in individual cases. It has often been said that the seismograph is a new structure-finding tool for the geologists to use. Using a tool and using its product are two different things. One does not use an automatic screw-threading machine when he buys a box of screws at the hardware store. Neither does the geologist

Jan 1, 1939

By J. B. Clemmer

Fluorspar is one of the most important nonmetallic minerals and is used extensively in the metallurgical, ceramic, cement, and chemical industries. The steel industry consumes most of it, but as the Mineral is the chief source of fluorine, it is becoming increasingly valuable to the chemical industry in the production of fluorine compounds. The development of nontoxic organic fluorides for use as refrigerants in mechanical refrigeration and air-conditioning units illustrates the increasing use of fluorspar in the chemical industry. Most domestic flurospar comes from deposits in the Illinois-Kentucky district, which centers around Rosiclare, Ill. About a dozen companies operate in the district, which comprises parts of Pope and Hardin Counties in southern Illinois and Crittenden, Livingston, and Caldrell Counties in western Kentucky. According to the latest available statistics, this district supplied 165,960 short tons of fluorspar in 1937, compared with the total domestic production of 151,230 tons. Imports totaled 37,063 tons.

Jan 1, 1939

By C. B. Richardson, R. D. Sprague

The year 1938 was the most active and successful in the history of the oil industry in southern Louisiana. Drilling showed a 16 per cent increase over that of 1937, with a total of 538 wells drilled, which yielded 315 oil wells, 19 distillate wells, 4 gas wells and 200 dry holes. Nineteen new fields were discovered during the year, all but three of which were completed by plugging back to sands previously drilled through. Electrical logging played a large part in these new discoveries as well as in the discovery of new sands during routine development of fields. Fourteen of the new discoveries produced oil, and five produced only gas and distillate. Southern Louisiana continues to lead the world in depth of drilling, which is in part due to the great thickness of comparatively young deltaic sediments near the coast and the existence of numerous sands. The present development is rather evenly distributed over a coastal strip 100 miles wide. New Fields North Tepetate, Acadia Parish.—Atlantic Refining Company's No. 1 Klumpp was completed for a new field through perforations from 7960 to 7970 ft. The initial production was 65 bbl. of 54" gravity distillate and 4 million cubic feet of gas daily through a 1/4-in. choke with tubing pressure of 2850 Ib. and casing pressure of 2930 lb. The well is in see. 12, 7 S., 2 W., just north of Tepetate field. It was drilled to a depth of 8705 ft. and plugged back for its final completion. Atlantic's NO. 2 was completed in a new sand at 8300 ft., also for distillate. South Crowley, Acadia Parish.—Humble Oil and Refining Company's No. 1 Boyd Finch was completed in July 1938, as an oil well through perforations from 7318 to 7325 ft. after plugging from a total depth of 10,222 ft. After making several hundred barrels of oil, the well went to

Jan 1, 1939

The ore, as sent to the sulphide mill, is a mixture, in varying proportions, of oxidized ore from above the 450-ft. level and sulphide ore from above and below (to date mainly from above) that level. The oxidized ore consists essentially of quartz, with varying amounts of kaolin and clayey material which passes into the slime and, in excess, creates a serious problem in settling. Pyrite may be present in small amounts. The gold is free and extremely fine.The ore, classed as sulphide, consists of pyritic material in a quartz gangue. The sulphides have been exposed to weathering, leaching by descending solutions and attack by ascending gases and actual burning. The alteration products occur in widely varying proportions and this variation adds to the difficulties in settling and control of grinding and flotation.Copper Minerals.-Chalcopyrite is the principal copperbearing mineral with smaller and varying amounts of covellite, which is sometimes associated with chalcocite, both these minerals being apparently of secondary origin.Examination of tailing by Dr. Stillwell has revealed all stages between clean chalcopyrite, chalcopyrite tinged with covellite, covellite with residual cores of chalcopyrite and clean covellite.The chalcopyrite is free floating, very few particles of clean chalcopyrite being observed in the tailing from granular flotation. The chief tailing loss is probably as chalcopyrite occurring as small inclusions in pyrite...

Jan 1, 1939