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By Paul M. Tyler

Hafnium appears to be among the more abundant of the newly discovered elements . Though quite widely distributed in nature , its compounds chemically so resembled those of zirconium , its sister element , that it escaped detection until 1923 , when Coster and Hevesy announced the discovery of the element , to which they gave the name of " hafnium " , from Hafniae , the Latin name for Copenhagen , where their research work was performed . Hafnium has so far been found only as a minor constituent of zirconium minerals . Zirconium as an element was discovered more than 140 years ago , but only a few unimportant uses were found for the metal or its compounds until some 18 years ago ; it is still classed among the rarer commercial metals . It is not surprising , therefore , that hafnium has not yet found a definite place for itself in industry . Nevertheless it has commanded a considerable interest among scientists ; and in 1930 some 70 grams of perfectly pure oxide of hafnium were prepared in Europe . A commercial future for hafnium is already glimpsed in the radio industry , and its high melting point and electronic emissivity have already led to the taking out of patents for its use in radio tubes and incandescent electric lamp filaments and for the cathode surfaces of devices such as X- ray tubes and rectifiers .

Apr 1, 1931

By Frank E. Cash, Roy G. Stott

This circular describes four modern change houses of the Lake Superior iron - ore district , all conceived and constructed since 1937. The oldest change house described herein was constructed and occupied in 1938 , yet it embodies the modern improvement of air - conditioning . The purpose of this report is to describe and illustrate improvements with regard to health and safety features combined in the construction , arrangement , ventilation , heating ,lighting , and other features , with the aid of photographs , sketches , and diagrams . The modern change house is a fire - resistant structure in which intermingling of men in mine clothes and men in street clothes , hazardous dust , heat and humidity , crowding , poor lighting , slippery and muddy floors , and inadequate facilities for clothes and for bathing have been largely eliminated . The miner coming off shift at a modern mine no longer faces the elements when he gets off the cage . He travels through a tunnel to the change house , where he is cooled gradually by room temperatures as he passes from the mineclothes section and shower room to the street - clothes room . He is assured of dry clothes when he is ready for them . No longer is he sent out of the change house into a muddy yard to drive away as best he can . The modern change house has an improved parking lot and graveled or concreted walkways from it to the change house entrances .

Jan 1, 1949

By Jr. Hazen

Two statistical techniques, the mean-square-successive-difference test and correlation, are used to investigate the problem of assigning an area of influence to an assay. Data from five hydrothermal deposits, Climax molybdenum, Cebolla Creek titaniferous iron, San Manuel copper, Piedra Hueca copper, and Butte copper, are studied. Two groupings of the assays are used for the mean-square-successive-difference tests. One group involves an increasing sample volume by reaveraging assays to represent a longer sample intervals, the other by regrouping assays to represent longer sample intervals without a change in sample volume.

Jan 1, 1967

By R. E. Peterson

Scrap iron is partially oxidized at elevated temperatures in the selective oxidation process to produce iron oxide and a dense residual metal of high purity. Investigation of the process was confined to converting automobile hulks into useful products. In one test series, compressed, sheared automobile scrap was processed at 1,000° C in a 36-foot-long rotary kiln at feed rates ranging from 300 to 1,200 lb/hr. Less fuel was required to maintain the temperature at the higher feed rates because of the heat generated from the burning of the combustibles and the oxidation of the iron. The bulk density of the residual metal exceeded 75 pounds per cubic foot. In an attempt to lower the quantity of contaminants in the residual metal, another test was designed using automobile hulks which had been prepared by ripping, a low-cost method of scrap fragmentation. Before oxidizing the ripped scrap approximately 62 percent of the total copper was removed in a tumbling, screening, magnetic separation and hand-sorting system. Cast iron made from the residual metal obtained by selective oxidation contained 0.15 percent copper; iron oxide scale obtained from the kiln averaged 0.13 percent copper. Pellets made from the scale demonstrated compressive strengths necessary for blast furnace reduction; lead and zinc were removed by volatilization when the induration was performed in a reducing atmosphere.

Jan 1, 1972

By F. E. Armstrong

A program with the objective of developing a fast, accurate instrumental method of analyzing mine dust for incombustible content has been underway in the Bureau of Mines for several years. Several prototype instruments making use of a gamma-ray backscatter technique have resulted. Although extensive laboratory testing has shown that these instruments are accurate under laboratory conditions, only extensive field testing will prove their ultimate practicality and usefulness. This report shows that under most conditions these devices are at least as accurate as the volumetric method and much faster in use. Other data obtained during the same study concerning mine dust are presented; these concern moisture content, sample bulk density distribution, and some particle size distribution information.

Jan 1, 1973

By Robert S. Warfield

The Federal Bureau of mines and U.S. Geological Survey conducted exploratory investigations and geologic mapping in the Wishbone Hill district of the Matanuska coalfield almost continuously from 1942 through 1958. These investigations delineated reserves of high-volatile bituminous coal necessary to supply the rapidly expanding military and civilian requirements in the Anchorage area. This report describes the program conducted by the Bureau of Mines from 1949 through 1958, and briefly summarizes previous investigations, the results of which have already been published. The coal-bearing structure on both the north and south limbs of the prominent Wishbone Hill syncline was explored by 8,719 feet of churn drilling and 25,460 feet of diamond-core drilling. A total of 33 holes were drilled ranging in depth from 60 to 2,114 feet. To supplement the drilling operations, bulldozer and dragline trenching were undertaken at key locations; about 25,000 cubic yards of dragline trench were excavated in the vicinity of the old Premier mine.

Jan 1, 1962

By L. C. IlsLey

Cooperation between the United States Bureau of Mines and the Safety in Mines Research Board of Great Britain, continuous, since 1924, s made possible this and other papers on safety subjects. Grateful acknowledgment is made to representatives of the board for their assistance in arranging visits to several mine-safety stations, and to F. R. Wynne, Deputy Chief Inspector of Mines, for arranging visits to mines in Great Britain and certain other countries in Europe. During the summer of 1927 the writer had the privilege of visiting the mine-safety testing stations An Great Britain, Belgium, Germany, and France, in the order named. All of these countries have large coal mines, many of which are rated as gassy. Therefore, a the installation of electrical equipment is contemplated each of these countries is confronted with the same safety problem as is the United States that is, the development of electrical equipment that will not, ignite gassy atmospheres should they through neglect or accident surround the equipment. The means employed by these countries in safeguarding gassy mines should therefore be of general interest to safety engineers of American coal mines, and a brief survey is given for each of the four countries mentioned. The fourth or last of these surveys covers conditions in France.

Jan 1, 1929

By Fred A. Williams

The cause of many deaths and extensive property damage in coal mines resulting from explosions and mine fires has been directly attributable to electric cable failures (including splice failures). The Federal Bureau of Mines data show that out of 355 underground coal mine fires investigated from July 1952 to January 1960, 103 (29 percent) were directly related to trailing cables. These cable failures resulted in the death of 7 men and injuries to 37 others. These potential hazards have become greater, obviously, through the widespread adoption of mechanized mining methods with electric-driven machinery powered through trailing cables according to Young,4 68.1 percent of the total bituminous and lignite production of the United States was mined underground in 1959. About 85 percent of this production was attained by mechanized loading methods. A large majority of the mines using the hand- loading methods also used equipment with trailing cables such as cutting machines, drills, and gathering locomotives. The problem of minimizing the loss of life, resources, and equipment from cable failures should be of concern to the management of all coal mines. It would be misleading to imply that no consideration has been given to the problem and its associated hazards. Through research cable manufacturers have endeavored to develop trailing cables that will withstand the severe service imposed by underground mining conditions. Technical research groups have undertaken studies for determining improved procedure and materials for field splices. Coal companies have instituted cable maintenance programs with a view toward the reduction of cable failures and consequent improvement in safety and efficiency of operations. Safety agencies are alert to unsatisfactory cable handling practices, poor workmanship in field splicing, mechanical

Jan 1, 1962

By N. H. Darton

In mining coal in the anthracite region of Pennsylvania the general custom has been to leave a large percentage of the coal in place as pillars to support the roof. Evidently any practice that involves partial waste of an important mineral resource is bound to be discarded. It is well recognized that one method of obviating probable waste is to fill the workings with cheap or worthless materials, a process extensively employed in the anthracite and some European mines. At present many of the collieries in the anthracite region of Pennsylvania are utilizing refuse from the old culm banks, which formerly were prominent features in the landscape, and are flushing the fine waste underground so that pillars may be reduced in size or removed. As a result the banks are now disappearing and soon will be gone. The fine culm from the breakers and rock from the mines will continue to be available, but the volume of these materials is insufficient to replace any considerable proportion of the coal removed. The next stage of progress suggested is the use of sand. Fortunately there are available large deposits of this material, much of which can be handled by dredges and pumps. This report is issued by the Bureau of Mines in the interest of safer and more efficient mining methods. I ts purpose is to describe the sand deposits in the northern anthracite coal field in Luzerne and Lackawanna Counties, Pa, Much of the information available is presented in the map, Plate I. Field studies, mostly preliminary, were made in the summer of 1911 to determine the distribution, amount, and character of the larger deposits. It was not thought desirable to make a detailed examination of the region because when the coal companies decide to utilize the sand their engineers will make precise surveys and drill test holes. In preparing the map the various coal companies were consulted; they contributed a large number of facts, especially as to the deposits in the buried valley of the Susquehanna between Pittston and Nan- ticoke, where nearly 1,000 test holes have been bored. The results of these borings were placed at the author's disposal, and have been utilized in drawing the boundaries given in the wide valley area and its extensions up Lackawanna River and NewportCreek. Wyoming Valley contains deposits of sand that are 100 feet thick over a wide area, 200 feet thick in places, and over 300 feet thick in the deep old channel south of Plymouth.

Jan 1, 1913

By A. C. Fieldner, G. W. Jones

Tests were made at the Government Fuel Yard , operated at Washington , D. C. by the Bureau of Mines , Department of the Interior , in order to determine and improve the adjustment of the carburetors on the trucks used for transporting coal from the Fuel Yard to the different Government buildings in Washington . The tests were made possible through the hearty cooperation of G , S. Pope , engineer in charge of the Fuel Yard . Joseph Burrows and A. E. Foote of the garage department assisted during all the tests and supplied information on the mileage obtained by the trucks for the months preceding and succeding the time the tests were made . The Mack trucks used range in capacity from 2-1/2 to 7-1/2 ttoonnss .. The majority of the carburetors were Stromberg G- 3 type , as shown in Table 2. During the winter months , when the demand for coal is heavy , from 30 to 35 trucks are used . At the time the tests were made , only about ten of the trucks were in daily use , owing to the small demand for coal during the summer months , and scarcity due to labor conditions . Samples of the exhaust gas were taken on the trucks kept in service for summer hauling in order to determine the carburetor adjustment as used . Changes were then made to a more economical adjustment wherever possible , without sacrificing flexibility of operation and power . In every case the adjustments were maintained for maximum power , but were adjusted to the leanest position to give that power . In all but one case the carburetors were found to be adjusted too rich for maximum power and economy . These results are considered in detail in a later part of this report .

Jun 1, 1923

By Ludwig Schmidt

This report, the second of a series, presents the results of laboratory corrosion studies which were made in connection with a one-year test on aluminum lease tanks conducted by the United States Bureau of Mines. Part 1 of the report contains the results of the field tests. The studies were made on an oil lease in a so-called "sour district," near Borger, Tex., where free hydrogen sulphide accompanied the production of oil, gas, and salt water. Steel tanks previously used on the lease had suffered severe corrosion, because steel is inherently susceptible to attack by hydrogen sulphide. Because of the high resistivity of aluminum to the action of hydrogen sulphide, it was believed that this metal had promising possibilities as a material for the construction of lease tanks in "sour districts." The results of the one-year field test proved that aluminum lease tanks will withstand corrosion by hydrosulphide, but it as found that aluminum was susceptible to attack by salt water, which was invariably present in certain portions of the tanks, and that hydrogen sulphide accelerated this salt-water corrosion in an indirect manner, as will be explained hereinafter. In order to study corrosion conditions encountered in the tanks during the test period, a laboratory was maintained at the site of the aluminum lease tanks.

Jan 1, 1931

By M. J. Sheridan

"INTRODUCTION In December 1942, the-Bureau of Mines reported favorably on a proposal to grant Government assistance-in constructing an access road (consisting principally of a timber-pile bridge across the Rio Grande at Hot Springs, N. Mex.) to the property under lease to the United States Fluorspar Co. At that time the property was being developed actively, and there appeared to be no immediate-need for exploratory or metallurgical assistance by the Bureau of Mines.Because milling facilities were inadequate; the access-read project was eventually disapproved, but prior to disapproval the company had discontinued operations. In June 1943, exploration was resumed by the Humphreys Gold Corporation of Denver, which had subleased the property. Difficulty of access continued to interfere with exploratory progress. In July 1945, at the request of the lessee, the Bureau of Mines directed sampling, using company employees.At the completion of this sampling program, the Bureau of Mines concluded that the property was potentially a important source of fluorite but that further development for production appeared to depend largely on the establishment, by exploration, of adequate reserves. Because of the relatively easy position-of metallurgical-grade concentrate and ores, it also was deemed advisable to investigate the possibility of producing acid-grade concentrate from the ore, for which a demand was becoming evident. Accordingly, a program of trenching, diamond drilling, and metallurgical testing was undertaken by the Bureau. The results of its investigation are reported herein."

Feb 1, 1947

By Forrest T. Moyer

In 1969, the number of fatal injuries in the coal mining industry was lower than in any previous year and the number of nonfatal injuries was lower than in any preceding year except 1968. Fatal injuries in 1969 totaled 203 with frequency rates of 0.85 per million man-hours of worktime and 0.36 per million tons of coal These rates were new annual lows. Nonfatal injuries totaled 9,917 with frequency rates of 41.76 per million man-hours and 17.42 per million tons. The severity rate for fatal and nonfatal injuries combined was 7,359 days lost or charged per million man-hours. The average severity was 173 days lost or charged per injury. These statistics represent the injury experience of an average of 133,302 employees per day working an average of 225 days in 5,955 coal mines for a total of 237-5 million man-hours worked and a coal output of 565 2 million tons

Jan 1, 1973

By J. J. Shields

The Bureau of Mines observed two different types of longwall mining; the advancing longwall method and the retreating longwall method at seven bituminous coal mines located in five of the coal producing states. In two mines using the advancing face method, the coal faces were abandoned because of roof failures and poor production. In the other five mines using the retreating method, roof control was good as was production. The success of longwall mining depends on good roof control and good production. The use of self-advancing hydraulic roof supports, such as Westfalia, Dowty, and Wanheim props along with Westfalia coal planers and the Anderton and Eickhoff shearer-loaders have been a factor in recent successes.

Jan 1, 1967

By E. Morrice, R. D. Smith

Thermal expansion and electrical resistance measurements were made on cerium metal from 4° to 300° K. The apparatus developed , including a specimen holder and a cryostat system , are described along with the experimental techniques used in obtaining the measurements . The total linear thermal expansion Data at of 99.83 weight - percent cerium metal between 4 ° K and room temperature was 4.24 percent . The resistivity at 4° K was 7.0 x 10-6 ohm- centimeter . 4° K indicate a fundamental relationship between residual resistivity and purity of cerium metal . The effects of annealing and repeated thermal cycling on resistivity were determined .

Jan 1, 1964

By J. E. Murphy

A method is being developed by the Federal Bureau of Mines for recovering lead metal from galena without the generation of SO2. Lead chloride is obtained by leaching lead concentrate at a temperature of approximately 100° C with FeCl3 solution: PbS + 2FeCl. " PbC1 2 + 2FeC1 2 + S. Electrolysis of the PbCI 2 product in a fused-salt bath results in deposition of molten lead metal at the cathode and evolution of chlorine at the anode. The chlorine can then be absorbed in the spent leach solution to regenerate FeCl3 for recycling. Optimum electrolyte composition was a PbC12-LiCl eutectic containing 7.6 wt-pct LiCl. The PbCl2-NaCl eutectic also proved satisfactory. Electrolysis in the PbCl2-LiCl bath at 450° C yielded 99 pct current efficiency at a current density of 5 amp/in2 with an energy requirement of only 0.24 kW-hr/lb metal produced. This compares with 98 pct current effi¬ciency and 0.26 kW-hr/lb metal produced for the PbCI2-NaCI bath. A typical lead deposit contained less than 100 ppm total detectable metallic impurities. At the low temperature employed for electrolysis, there was essentially no vaporization of Pb or FbC12.

Jan 1, 1974

By J. T. McCartney

The Bureau of Mines has developed an automated reflectance scanning microscope system, primarily for determination of volume proportions, size distribution, and mode of association of the physical (petrographic) components of coals. The process, which is potentially more rapid and objective and less tedious than a visual microscopic procedure, involves magnetic tape recording of several millions of reflectance readings on micro-meter sized areas of polished coal surface and computer analysis and interpretation of some characteristics of the coal components. The system was tested in a study of pyrite distribution in steam coals. The application was essentially successful, but defects in polished pyrite surface characteristics and problems in adequate sampling prevented completely satisfactory results. Pyrite con-tent and coal-pyrite particle association could be determined nearly as well as by visual microscopy, but size distribution data were less acceptable.

Jan 1, 1969

By M. Clair Smith

This report is one of a series describing exploration, development, mining methods, and costs at United States open-pit mines; the Bureau of Mines prepares and publishes them in cooperation with the mining companies. Their purpose is to promote development and conservation of our mineral resources by disseminating technologic information on mining methods and practices at various United States mines. The exploration, development, equipment, and mining of a large, oxidized-copper ore deposit by open-pit methods, the leaching of the ore with sulfuric acid solution, and the recovery of the copper as cement copper are described herein.

Jan 1, 1958

By Joseph M. Singer

Having established that sodium chloride reduces the incendivity of explosives, the Bureau of Mines studied the effect of sodium nitrate in reducing ignition hazards. Gallery experiments showed that sodium nitrate reduced the incendivity of certain explosives to 8 percent natural gas in air but increased their incendivity to coal dust predispersed in air. Laboratory experiments using hot jets from explosions of stoichiometric mixtures of methane-oxygen-nitrogen showed that both sodium chloride and sodium nitrate reduced the incendivity to methane, to mixtures of coal dust and methane) and to coal dust. The difference between the gallery and laboratory results with respect to coal dust is attributed to temperature-time effects.

Jan 1, 1967

By Paul Hatmaker

Pumice and pumicite are siliceous volcanic substances quite similar in chemical composition , but somewhat different in physical properties , manner of formation , and mode of occurrence . Production in the United States has increased from 23,271 tons valued at $ 94,943 in 1910 , to 56,843 tons valued at $336,099 in 1930. Both pumice and pumicite are included in these figures as it has been impractical to collect statistical data on the separate commodities .

Mar 1, 1932