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By E. D. Eastman

There are three researches upon the specific heat of water vapor by the method of explosion that are sufficiently advanced in technique and suitable in plan to justify careful study of their results , with the double purpose of fixing the best available experimental values and indicating the attainable accuracy of the method. These three researches comprise the work of Pier , Bjerrum , and Siegel.5 The work of earlier date than Pier's suffers from obvious inaccuracy of measurement , while the experiments more recent than Siegel's , such as those of Womersley6 , of Bone and his collaborators , and of Maxwell and Wheeler , 8 are for the most part not well designed for the accurate determination of the heat capacities in question . Some of the errors to which they are especially subject have been discussed by David and by David and Thorp.

Sep 1, 1930

By N. A. C. Smith, D. D. Stark

"Sulphur is apparently a normal Constituent of crude petroleum, but in most crudes is present in percentages of less than one-half of one per cent. Some crudes, however, contain more, and occurrences have been reported of heavy asphaltic oils with as much as five per cent of sulphur.Occurrences of Sulpher-bearing CrudesIn North America, the fields rest of the Mississippi River are almost entirely free from sulphur oils, the time oil from Northern Ohio and Indiana, and the Potrolia crude in Ontario, being practically the only ones which contain sulohur in amounts over 0.5. per cent. In the Mid-Continent district the production of high sulphur crude in general is small and unim¬portant. The two main excentions are the Healdton field in Oklahoma and the El Dorado field in Arkansas, both of which produce oils with considerable sulphur content. In the Wyoming field, one sand, the Ember Sandstone, pro¬duces a crude of high sulphur content, and it is probable that this crude rill be of considerable importance as production increases. At present, however, very little crude is produced from this formation. In the Gulf Coast conditions are irregular, some crudes being low in sulphur and others comparatively high. The same is largely true of California. The crudes of Mexico contain notable amounts of sulphur, and as they have been of great commercial importance in this country, a typical sample of light Mexican crude was selected for the present study. It is probable that the results obtained poly also (but to a lesser degree) to other sulphur-bearing oils. An analysis of this crude will be found in Table 3, also analyses of other typical sulphur-bearing crudes from different sections of the United States."

Mar 1, 1924

By John Nagy

A study was made in the Bureau of Mines experimental coal mine of factors affecting gas ignition by a cutoff explosive charge. Experiments showed that, although gas could be ignited under some circumstances, the probability under normal mining conditions would be low. The use of permissible explosives, relatively short-delay intervals in firing adjacent holes, blasting to a 6-inch kerf, and reasonable care in the placement of the holes favor safe blasting and are current practice in mining. The experiments also showed that the weight of the charge is not a primary factor in the ignition of gas by a cutoff charge. The quenching action of a first charge on the igniting action of a second was verified in a supplementary study. Related experiments have shown that gas at the face may be ignited by a single charge of explosive when fired with a light coal burden. Permissible explosives were less hazardous under these conditions than nonpermissible explosives. The frequency of gas ignition in cutoff and single-charge experiments increased as the linear distance between the sheared face and the opposing mine rib increased.

Jan 1, 1960

By Geoffrey C. Huggins

Diagnostic: tests were performed on a production ST-5A Load-Haul-Dump machine manufactured by Wagner Mining Machinery Company to evaluate and rank order noise sources. The diagnostic evaluation indicated that the major noise sources were the transmission, the engine, and the cooling fan. This phase was followed by implementation of recommended noise control treatments, which included vibration isolation of the transmission, a transmission enclosure, an engine enclosure, and modifications of the inlet to the cooling fan. The final step in the program was an underground operational period which began on 31 August 1976 at the National Gypsum Mine in Shoals, Indiana. The noise control treatments successfully reduced the LHD operator noise exposure by 7 dB(A), thus increasing its allowable operation time by a factor of 2.7. Actual measurements made underground using noise dosimeters have indicated that, during, a typical shift, the noise control treatments have reduced the fractional exposure to an allowable level. The report discusses the mechanical aspects of the LHD, its noise sources, the treatments applied, the final levels achieved, and field experience with the noise-controlled machine.

Jan 1, 1977

By Charles B. Kenahan

Vanadium is subject to only light corrosion in phosphoric acid at temperatures up to 60° C. and has a moderate corrosion rate in this acid at 100° C. It is relatively corrosion resistant in sulfuric and hydrochloric acids up to 60° C, but corrodes rapidly at 100° C. It corrodes rapidly in dilute nitric acid at 35° C. Vanadium is almost inert in 10-percent solutions of formic, acetic, lactic, tartaric, and citric acids; in 9-percent oxalic acid it corrodes slowly up to 60° C. and rapidly at 100° C. Vanadium is resistant to corrosion in substitute ocean water, tapwater, and in 3-percent sodium chloride and 10-percent sodium hydroxide solutions. It is readily attacked, however, by 20-percent ferric chloride, 20-percent cupric chloride and 5-percent mercuric chloride solutions. Vanadium is protected by contact with magnesium, aluminum, and steel SAE 4130 in substitute ocean water, by magnesium and aluminum in 3-percent sodium chloride solution, and by magnesium in tapwater. Vanadium protects copper in substitute ocean water. When vanadium and stainless steel are coupled in sulfuric acid solutions, both metals are usually unaffected by contact, whereas the corrosion rate of titanium in sulfuric acid is greatly reduced by contact with vanadium.

Jan 1, 1962

By R. Barany

The heats of formation of seven substances were determined by solution calorimetry. At 298.15° K, the heat of formation of lithium sulfate from lithium, rhombic sulfur, and oxygen was -343.1 ± 0.7 kcal/mole, and the heat of formation of lithium sulfate monohydrate from lithium, rhombic sulfur, oxy-gen, and hydrogen was -414.3 ± 0.7 kcal/mo1e. For the silicates, the heats of formation at 298.15° K from the elements were kaliophilite, -503.8 ± 0.5 kcal/mole; leucite, -721.6 ± 0,8 kcal/mole; eucryptite, -505,2 ± 0.6 kcal/mole; alpha-spodumene, -727.9 ± 0.9 kcal/mole; and beta-spodumene, -721.1 ± 0.9 kcal/mole. The corresponding heats of formation at 298.15° K from the constituent oxides were kaliophilite, -42.7 ± 1.1 kca1/mole; leucite, -42.8 ± 1.1 kcal/mole; eucryptite, -16.1 ± 0.7 kcal/mole; alpha-spodumene, -21.0 ± 0.7 kcal/mo1e; and beta-spodumene, -14.3 ± 0.7 kcal/mo1e.

Jan 1, 1966

By William H. King

The Nevada Massachusetts tungsten deposits (fig. 1) are in the Mill City Mining District in north-central Pershing County, Nev., about 37 miles southwest of Winnemucca. Contact metamorphism of thin limestone beds within a series of metamorphosed sedimentaries formed scheelite-bearing ore bodies. These deposits are distributed over a wide area. A Bureau of Mines development program was started January 11 d was completed on July 25, 1941. This work was centered on the outer and less explored beds in the district and comprised trenching, sampling, and diamond drilling. Exploratory work was done in cooperation with the U.S. Geological Survey. Project work substantially increased the reserve tonnage of marginal ore in three of the areas explored and proved the nonexistence of tungsten in a fourth area. The following pages summarize the history of the district, outline property ownership, and describe physical features and ore deposits. The plan and results of the work performed by the Bureau of Mines are presented along with geologic and topographic maps, assay maps, and diamond drill-hole logs.

Jan 1, 1950

By Nancy Potts, M. G. Barker, W. C. Holliman

"SUMMARYThis report on the characteristics of commercial aviation gasolines presents compilations of inspection test data furnished on their products by manufacturers of commercial grades of aviation gasoline, and special data obtained in Bureau of Mines laboratories on samples of these gasolines. Data and physical samples for the survey were submitted by 15 manufacturers on 18 grade 80, 21 grade 91/98, 22 grade 100/130, end 10 grade 115/145 aviation fuels.The inspection test data supplied by the participating manufacturers consist of octane and performance numbers, tetraethyllead content, dye color, and other characteristics usually listed in aviation gasoline specifications, such as AN-F-48a or ASTM Designation D910-47T. These data are tabulated and averaged by grades in tables 1 through 4 and, as reported, meet the AN-F-48a and similar specifications with a few exceptions. Two grade 80 gasolines show a lean-mixture octane rating slightly below 80.0, and 91/98 grade fuel shows a lean-mixture rating of 90.9 and a rich-mixture rating of 97.5, two 100/130 grade gasolines have a rich-mixture performance number slightly below 130.0, and one 115/145 grade gasoline shows a rich-mixture performance number of 144.5. However, octane and performance number averages are above the mini¬mum requirements for each grade. Tetraethyllead content in the 91/98 and 100/ 130 grades generally is above the maximum outlined in these specifications, whereas dye color for each of the four grades, with the exception of two gasolines in grades 80 and 100/130, is that designated for the particular grade. Distillation requirements, with a few exceptions at individual points, are met by gasolines of all grades. Reid-vapor-pressure, copper-dish-residue, heat-of-combustion or aniline-gravity-constant, freezing-point, and copper-strip-corrosion requirements are met by all gasolines so far as reported. No data for some of these tests wore submitted on a few of the gasolines. One gasoline, grade 115/145, shows a sulfur content greater than the specified maximum."

May 1, 1948

By John Nagy

Dust explosion data obtained in laboratory tests by the Bureau of Mines are presented for 181 miscellaneous materials that present an explosion hazard. Data are given also for 50 dusts that present primarily a fire hazard and for 88 dusts that did not present an explosion hazard.

Jan 1, 1968

By Mark R. Pettitt

The results of an extensive research and development program to reduce the noise generated during coal cutting are presented. The characteristics and magnitude of continuous miner coal cutting noise sources are defined. This work consisted of development of a simulated coal ,cam to facilitate above-ground coal cutting tests, noise measurements in a reverberant acoustic chamber during simulated mining operations of a continuous miner (cutting the simulated coal scam), and noise measurements in an underground coal mine during continuous miner operation. In-mine and laboratory test results were in excellent agreement for both A-weighted overall levels as well as A-weighted one-third octave band spectra. Methods to reduce coal cutting noise are presented. These methods take full advantage of the dynamic characteristics of the forces generated during coal cutting. Dynamic cutting force isolation was shown to be a very effective technique. Finally, a continuous miner was equipped with a cutter head that incorporated (among other design factors) cutting force isolation. Successful, lung term, in-mine use of the cutter head demonstrated coal cutting noise at the operator's station of less than 90 dBA and 50% coal, 50% rock cutting of less than 93 dBA.

Jan 1, 1985

By A. C. Rice

This report describes a chemical process for preparing solutions of trivalent rare-earth chlorides from sulfate solutions obtained by treating bastnasite concentrate. The chief impurity in the final solution is cerium, and this element is less than 1 percent of the rare-earth oxides. The solution is used directly in the separation of rare-earth elements by ion-exchange methods. The attractive features of the process are that the chemicals are inexpensive and the steps few. The process starts with precipitating the rare-earth hydroxides from sulfate solutions with caustic soda. After the hydroxides are dried to oxidize the cerium, they are treated with dilute hydrochloric acid to dissolve away the trivalent rare-earth elements, leaving the tetravalent cerium. Details for controlling the leaching step are described. The process shortens older procedures by omitting the usual oxalate or double-sulfate-precipitation step.

Jan 1, 1959

By L. L. Brown

As part of the Federal effort to help maintain an adequate supply of fertilizer materials, the Bureau of Mines conducted research to characterize complex low-grade Michigan phosphate materials and to devise methods for recovering fertilizer-grade phosphate concentrates. The rock is from middle Precambrian sedimentary formations in the Marquette Range located in the central part of the Upper Peninsula of Michigan. Occurrence of phosphate-bearing sediments in Precambrian rocks is rare. This deposit, containing 12 to 15 pct P205, is believed to be the richest Precambrian phosphate deposit in the United States. Petrographic examination showed that the conglomeritic rock contains crystalline apatite both in "black pebbles" and in quartz matrix. Attrition scrubbing and sizing tests showed that there is no tendency for phosphate to concentrate in any of the sized fractions. In beneficiation tests, which included grinding to minus 325 mesh followed by phosphate mineral flotation using a fatty acid-fuel oil collector, a phosphate concentrate was obtained that had a grade of 30 pct P205 and a P205 recovery of 72 pct. This concentrate should be suitable for fertilizer manufacture.

Jan 1, 1981

By Earl L. Hastings

Although the principal market for diatomite in the United States is in the East,4 production of the material is presently restricted to the West, because the deposits are larger, mining costs are cheaper, and the quality of product is better than that obtained from other domestic deposits. However, Tallahatta diatomite, occurring in Choctaw and Clarke Counties, Ala., has a freight rate advantage, which should encourage competition for those market that are now being supplied with the purer diatomites from the western deposits. For this reason, diatomite occurrences in the Tallahatta formation were examined by the Bureau of Mines and physical properties of samples from the deposit were determined to obtain additional data for use by any potential producer who wished to evaluate the material for its commercial possibilities. In 1894 K. M. Cunningham5 found that the buhrstone formation (now known as the Tallahatta formation) contained "siliceous shells of marine diatoms, radiolaria and foraminifera, thus being rather of the nature of tripoli or diatomaceous earth than of a true clay." Cooke6 and Semmes7 also reported the Tallahatta formation to be composed principally of diatomaceous earth with accompanying beds of sand, clay, and sandstone.

Jan 1, 1963

By Fred D. DeVaney

The Mesabi iron district of Minnesota has a potential production of over 50 million tons of iron are annually. The large shipments of ore each year are gradually depleting the reserves, and if the present rate of production is to be maintained there must be a growth in the present available ore supply. Growth is a natural course. The growth of a city may be affected by the addition of city blocks or by the improvement of utilities necessary for its betterment. These may go on in the order named or concurrently. The city-block type of growth of the Mesabi has been tremendous, and the "betterment" type has followed in due course. Probably the former has reached its limit, and if so, more time will be allotted to the latter. It is not the in¬tent of this paper to present either a eulogy of the wonderful mining methods or a history of the milling, but it is pertinent to say that if the lean-ore area continues to produce, the continuance will be more the result of further improvement of milling methods non well under way than of extension of boundaries by the city block plan of growth.

Jan 1, 1932

By Margaret E. Egan

Reliable fire detection is essential for both safe evacuation and containment or extinguishment. In order to increase reliability by reducing the number of nuisance fire alarms in underground mines that use diesel-powered equipment, the U.S. Bureau of Mines has developed a diesel-discriminating fire detector (DDD). It was designed to discriminate between smoke produced by a fire and the smoke-laden exhaust of a diesel engine. Experiments were conducted by the Bureau to compare the smoke detection capabilities of the DDD with those of conventional fire detectors in response to smoldering coal and conveyor belting. A comparison was made among the alarm times of a carbon monoxide (CO) detector with an alarm threshold of 5 ppm, a smoke detector with an optical density alarm threshold of 0.044 of', and the DDD with an alarm threshold of 0.025 V. The results show that the DDD will reliably detect developing coal and conveyor belt fires. The average time delay separating the DDD alarm from the first detector to alarm was 76 s for smoldering conveyor belt and 65 s for smoldering coal. The longest time delay between the response of the DDD and the first detector to alarm was approximately 120 s.

Jan 1, 1993

By R. J. Morrell

The Bureau of Mines conducted a series of laboratory experiments to test a cutting technique for hard rock using large-scale drag cutters. Cutting experiments were performed on rocks ranging in compressive strength from 10,000 to 27,000 Ib/in2, using large drag cutters from 3 to 6 in. in width. The tests were conducted on a special test apparatus, called a ripper tester, which made a curvilinear cut across the rock sample while measuring the cutting force acting on the drag cutter. The cutting method that evolved from these experiments is called ripper cutting, and its energy efficiency appears superior to all other large-scale mechanical fragmentation techniques. In addition, the method cre-ated very little dust, and the wear on the bits was negligible. A fragmentation system based on ripper cutting was then devised, and a large-scale test device was fabricated to allow full-scale laboratory testing of the system. The results of these tests will be published in future Bureau reports.

Jan 1, 1986

By James C. Cawley

The Bureau of Mines conducted an investigation to statistically determine the mean current or voltage for resistive, inductive, and capaci-tive circuits that would cause spark ignitions in 8.3% methane-air, 5.3% propane-air, and 7.8% ethylene-air mixtures. Each mean ignition current or voltage was determined on the basis of 100 trials. Each trial consisted of 400 revolutions, 200 in each polarity, at 80 rpm of the standard breakf1ash apparatus. In general, spark ignition curves published in UL 913 for resistive and inductive circuits represent approximately the mean current values determined in this study, while published capacitive circuit values in methane are considerably less than the mean voltage values from this study, especially for a capacitance of less than 100 ~F. For resistive and inductive circuits, spark ignitions were obtained at currents con-siderably below those in the published curves, but this study was not optimized to find minimum ignition values. This report defines "safety factor" as applied to intrinsic safety testing as the energy ratio of the mean values of ignition current or voltage for two test gases. The safety factors presented in this report are not constant with voltage or current and, therefore, are not recommended for use.

Jan 1, 1986

By G. V. Sullivan, G. F. Workentine

Beneficiation studies were conducted by the Bureau of Mines on three samples of low- grade chromite - bearing material from the Stillwater complex of Montana . The objective of the study was to develop methods for recovering chromite from low- grade materials to improve the domestic reserve situation . Samples were obtained from the three largest deposits in the district , Mouat , Benbow , and Gish . The chromic oxide ( Cr₂ 0 ) content of the ore and of the chromite was about the same in each of the samples . The major gangue constituents ranged from clean olivine in the Mouat sample to such altered minerals as serpentine and talc in the Benbow and Gish samples . Tabling , flotation , high- tension electrostatic separation , and combinations of processes were applied to each ore . Treatment of the Mouat sample ( 9.95 percent Cr₂ 0 ) by high- tension electrostatic separation , a combination of tabling and high- tension electrostatic separation , and tabling with middling retreatment resulted in concentrates that graded 42.8 , 42.0 , and 40.7 percent Cr₂03 at chromium recoveries of 85 , 86 , and 84 percent , respectively . Other techniques were less selective . 2 The Benbow sample ( 7.75 percent Cr₂0 ) responded most selectively to tabling with middling retreatment and a combination of tabling and hightension electrostatic separation to produce concentrates of 40.1 and 39.5 percent Cr₂g with each process having a chromium 2 recovery of 69 percent . Response of the Gish sample ( 8.04 percent Cr₂03 ) to the various concentration techniques was about the same as that of the Benbow sample , but in general , somewhat less selective . A combination of tabling and high- tension electrostatic separation resulted in a concentrate that contained 71 percent The Mouat mine was reopened in 1953 when the American Chrome Co. contracted with the Federal Government to produce 900,000 tons of chromite concentrate . The ore , averaging 20.2 percent Cr₂03 , was treated by tabling to produce a 38.5 - percent Cr₂ O concentrate.

Jan 1, 1964

By A. B. Needham

Graphite is a raw .material of considerable importance in both waxy and peace. Two types of graphite, classified according to particle size as flake and fines, are used, but the former is in much greater demand. The principal wartime use of graphite is in the manufacture of crucibles for melting brass and special alloys of copper and steel. Other uses in both peace and war are as lubricants, for foundry facings, and in paints, electrodes, batteries, motor and generator brushes, and a variety of other commodities. . This paper describes the operations of the Southwestern Graphite Co. of Los Angeles, Calif., which produces both flake and fine graphite from a property in Burnet County, Tex.

Jan 1, 1946

By G. B. Shea

In 192b, there wore 47 fatal accidents in the California petroleum industry, 14.6 per cent more than occurred in 1927 when 41 men lost their lives in the drilling, producing, manufacturing, and marketing divisions of the industry. This increase in the number of fatal accidents for 1928 has caused the first upward trend in the fatality curve of the California petroleum industry since 1923. In no other year during the 6-year period have the fatalities in any one year been greater than those for the preceding year. This fact should be given serious consideration and study by the petroleum industry, and an endeavor should be made to cause the number of fatalities again to decrease and conform to the previous gradual declining trend of the fatality curve. The following chart shows the trend of fatal accidents during the past six years:

Jan 1, 1929