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By J. H. Holden, C. C. Shale, G. R. Strimbeck, W. S. Bowie

Electrical characteristics are presented for air in a 2 - inch pipe - type electrostatic precipitator operating under dynamic conditions at temperatures of 600 ° to 1,500 ° F and pressures of 0 to 80 psig using a negative discharge electrode . Results of this one - geometry study show that current - voltage relationships are a function of air pressure and temperature and indicate that precipitators can be used at any temperature through about 1,350 ° F over the full range of pressure . Corona starting voltage and sparkover voltage vary directly with pressure and inversely with temperature . At temperatures above 1,350 ° F use of precipitators may be limited to operations at pressures somewhat above atmospheric pressure . Theoretical derivations are presented that relate the effect of gas density on corona starting voltage and the effect of ion mobility on corona current . Deviation from the theory is noted at high current levels . Theoretical discussion is presented to explain the apparent electrical limitations for use of precipitators at high temperature , low gas density , and high corona currents , conditions at which calculated ionic velocities are extremely high . Experimental results are interpreted in terms of the theory presented . 1,500 ° F thermal ionization does not appear to be a critical factor .

Jan 1, 1963

By Robert T. Beckman

The results of a preliminary investigation of compressive strength versus length-diameter (L/D) ratios of potash specimens and the statistical treatment of the data are summarized in this report. The purpose of the study was to evaluate a laboratory method for obtaining estimates of the strength of potash pillars during robbing operations. The specific objectives of this preliminary investigation were to test the method and the reliability (confidence limits) of the data, and to determine the number of additional specimens necessary for given confidence limits. The specimens were taken from three sites at two mines in New Mexico. The statistical analyses included the determination of the confidence limits for the data and the number of additional specimens necessary to obtain confidence limits of ±500 and 100 psi. The testing method was found acceptable, and estimates of the comprehensive strength, within 1500 psi, could be obtained by testing about 110 additional specimens from the three sites. The compressive strength of the specimens tested fits an empirical equation of the type

Dec 1, 1963

By Martin H. Stanczyk, I. L. Feld

Continuous open - circuit attrition grinding of a coarse commercial kaolin to produce paper - coating clay , which must have a particle size analysis of 70 percent or more minus 2 - micron equivalent spherical diameter ( esd ) , was studied by the Bureau . The coarse clay , containing about 11 percent minus 2 -micron esd material , was ground in a 10 - inch- diameter attrition grinder using continuous single- and multiple - stage grinding circuits . The clay feed rates varied from 10 to 480 pounds per hour . In some tests , the influence of varying loads of sand grinding media on particle size reduction was studied . Batch grinding tests also were made for comparative purposes . Multiple- stage grinding gave better results than single - stage treatment when equivalent raw clay feed rates were used . In the best test made , a product containing about 80 percent minus 2 - micron esd material was obtained when grinding 60 pounds of raw clay per hour using a three - stage grinding circuit . Power consumption in the test was about 318 kilowatt -hours per ton of clay treated or 475 kilowatt - hours per ton of minus 2 - micron esd material produced .

Jan 1, 1963

By M. B. Cooke, A. D. Bauer, E. W. Dean

The Bureau of Mines is collecting and analyzing representative samples of crude petroleum from all the producing fields in the United States , and the results are being published in a series of reports that are preliminary to the issue of a bulletin covering the entire survey . The bureau has recently completed a survey of crude oils from the Kansas district . In all 27 samples were collected and analyzed , under the direction of A. W. Ambrose , chief petroleum technologist of the Bureau. Valuable assistance was received through the cooperation of oil companies operating in the State , especially the Prairie Pipe Line Co. , and the Empire Pipe Line Co. The present report issued as Serial 2322 , on the Kansas crudes , forms the fifth of the series . Of the four previous papers , the first ( No. 2202 ) deals with crudes from the Eastern fields of the United States , the second ( No. 2235 ) with crudes from the Rocky Mountain district , the third ( No. 2290) gives additional data , cn viscosities and pour tests , for the crudes from these two fields , and the fourth ( No. 2293 ) covers the fields of northern Texas , northern Louisiana , and Arkansas . The details of the methods of collecting samples , making laboratory tests and interpreting results , have been discussed in these earlier reports . It has also been pointed out that the only adequate method of interpreting analyses of crude oils is to compare the individual reports with the analysis of some crude oil that is familiar to the operator . For this reason , no comprehensive discussion of the results of the Kansas survey is attempted, although some general statements may be made .

Feb 1, 1922

By G. S. Scott, G. W. Jones, F. E. Scott

An important activity of the Bureau of Mines is the promotion of safety in mining and industry . In connection with these activities , the Bureau determines the explosion hazards of combustible gases , liquids , and solids , and investigates means by which explosions may be eliminated or reduced in violence . The limits of inflammability and ignition temperatures of combustible gases , vapors , and solids are of practical importance because such materials can be manufactured , transported , and used with greater safety , provided the range of concentrations and temperatures that cause explosions are known. Acetic anhydride , ( CH3CO) 20 , with which this report is concerned , is a liquid at ordinary temperatures . It is used in the preparation of a number of organic chemicals and in the manufacture of photographic film and of artificial silk . It is perhaps the most important acetylating agent for industrial uses - a property that is especially important at this time because of its direct application in the manufacture of munitions . The sample tested was supplied by the Carbide & Carbon Chemicals Corporation . Its specific gravity was given as 1.083 at 20/20 . The vapor pressures , supplied by the manufacturer , are plotted in figure 1 .

Dec 1, 1943

By B. M. O'Harra

The residues resulting from the retort distillation of zinc ores have from 40 to 75 per cent of the weight of the original ore and contain from 5 to 15 per cent zinc . A rough estimate indicates that approximately 450,000 tons of residues are produced annually in the United States , containing about 36,000 tons of zinc . Besides the current production of residues there are at many smelter sites large accumulations from past operations which are available for treatment if this can be done profitably . In addition to their zinc content the residues contain much unconsumed coal , which has been carbonized during the distillation process , and those from most western ores also contain lead and silver . In this paper is summarized the information obtained in a survey , recently made by the Bureau of Mines , in cooperation with the Missouri School of Mines and Metallurgy , of processes which are in use or which have been suggested for the treatment of retort residues . The complete report of the survey is to be published as a Technical Paper of the Bureau of Mines .

Apr 1, 1923

By M. E. Tyrrell, J. Koster

This work was undertaken to determine the feasibility of making mixed diborides of two metals directly from the metal oxides , boron carbide and carbon . The diborides (Ti , V ) , B₂ , (Ti , Cb) B₂ , and ( Ti , Ta ) B₂ were prepared in a crucible resistance furnace at 2,100 ° C , and X- ray- diffraction analyses showed each was a homogeneous solid solution containing approximately equal molar contents of the given diborides . The diboride powders were cold - pressed ; sintered to 2,300 ° C , and evaluated for mechanical strength , rate of oxidation , and resistance to molten metals . The diboride ( Ti , Ta ) B₂ exhibited the best mechanical properties ; the diboride ( Ti , Cb ) B₂ , the lowest cumulative rate of oxidation . The mixtures were stable in the presence of molten aluminum and copper but were attacked by molten Ti , Zr , and Cr .

Jan 1, 1964

By Raymond B. Ladoo

SOAPSTONE

Feb 1, 1922

By Earl C. Lane

The Bureau of Mines is making a survey of petroleum products manufactured on the Pacific Coast from California crude oils . California crude petroleum is known to differ in some characteristics from the crude oil produced in other parts of the United States , and the claim has been made that the present Federal specifications are unduly severe when applied to the products made from California crudes . The main purpose of the present survey is to determine whether these claims are justified . This report deals only with California gasolines . Other products , such as burning oil , fuel and lubricating oils , will be taken up later . The samples reported were furnished in most cases , by the four large refining companies located on the Pacific Coast , although a number of samples of motor gasoline were purchased in the open market . In Los Angeles , samples of motor gasoline were obtained from service stations representing as many different refineries as possible . Inasmuch as San Francisco is one of the cities covered by the regular semi -annual motor gasoline survey conducted by the Bureau of Mines , it was not considered essential that the set of samples obtained from this city be as comprehensive as would otherwise have been necessary . The gasoline consumed in the States of Washington and Oregon is furnished for the most part by California refineries , and no effort was made to procure samples from these States .

Apr 1, 1922

By George J. Carter, George H. Todd, Hal J. Kelly

In July 1956, the Bureau of Mines and the J. R. Simplot Co. participated in evaluating and beneficiating drill-hole samples from the Bovill, Idaho, clay-silica deposit and in tests of the beneficiated products. The geology, mineralogy, beneficiation, and potential uses of the clay and quartz fractions of the Bovill deposit are described. Test work showed that a filler-grade clay having an apparent spectral reflectance of 78 percent can be made by bleaching, and by removing some of the submicron-size particles. A quartz product suitable for the manufacture of glass containers can also be made.

Dec 1, 1963

By O. C. Blade

This report on the properties of motor fuels sold through service stations in the United States is a continuation of a series of reports made in accordance with a cooperative agreement between the Coordinating Fuel Research ( C.F.R. ) Committee of the Coordinating Research Council ( C.R.C. ) and the Bureau of lines of the United States Department of the Interior . The first of these reports presented data on motor gasolines sold during the winter of 1935-35.4/ Further reports have been issued describing motor gasolines sold during the succeeding summers and winters to and including the summer of 1941.5/ No reports were made on motor gasolines sold during the winter of 1941-42 and during the summer of 1942 . However , starting with the winter of 1942-43 , the semi - annual reports have been resumed

Jan 1, 1945

By V. E. Homme, M. M. Wong

Tests were made in reactors ranging from 12 to 30 inches in diameter to develop methods for the preparation of sodium chloride - titanium lower chlorides ( dichloride and trichloride ) melts that contain titanium predominantly in the divalent state . Such melts are desirable as a starting material for the production of titanium metal or as an electrolyte for electrorefining of titanium . Sodium reduction of TiCl with an 18 - hour period of holding the reaction products in the molten state produced melts that contained titanium lower chlorides in TiCl₂ - to - TiCl , molar ratio of approximately 8 to 1. Sodium reduction of TiCl in a reactor with a shielded pipe weir , that required no melt -holding period , produced melts with a TiCl₂ - toTiCl , molar ratio as low as 4 to 1 . Reduction of TiCl4 with scrap titanium metal in molten sodium chloride produced relatively pure melts containing about 27 percent titanium in a Ticl₂ - to - Ticl , molar ratio of approximately 4 to 1 .

Jan 1, 1964

By Scott W. Hazen, Richard F. Link, George S. Koch

The Mi Vida mine , Big Indian district , San Juan County , Utah , is in an ore deposit of uranium and vanadium minerals disseminated in certain sedimentary beds of the Triassic Chinle formation . Statistical analysis of assays of samples taken from the ore body affords an estimate of the grade of the ore body and provides a prediction about the direction of best mineralization beyond the sampled area . The basic data analyzed are assay results for uranium ( Uз Og ) , vanadium (V₂O ) , and lime (CaO ) from 225 channel samples cut at 79 sample points . Through the use of appropriate statistical methods , particularly regression analysis , the grade of ore may be estimated more precisely than by conventional means , and the most favorable direction to extend the mine may be predicted . Frequency distributions of assay residuals for uranium , vanadium , and lime are compared to frequency distributions of assays without regard to trend . Correlations among these variables are obtained and interpreted . The statistical methods employed illustrate certain techniques that may be used to analyze assay data from ore deposits in general .

Jan 1, 1964

By L. T. MCELVENNY, Robert B. McElwaine, M. Clair Smith

Production of mercury from the cinnabar deposits of the southwestern Arkansas mercury district began in 1931 , reached its peak in 1942 , and ended in 1944. The mines are now idle . Virtually all the cinnabar was obtained from deposits in a belt , about a mile wide , of steeply dipping sandstone beds in the overriding blocks of three thrust faults . The belt was productive for a length of about 27 miles eastward from eastern Howard County, through Pike County, into Clark County . During the early life of the district, Federal agencies watched and recorded its progress as a contributor of a strategic metal, and later, during the war, conducted investigations designed to advance its development . In 1941 , the Bureau of Mines and the U. S. Geological Survey cooperated in investigations on eight mineralized areas in the western part of the district , to wit : Hales mine , U. S. mine , Lulu Bell property, Hopkins Hill , East Gap Ridge , Gap Ridge , Parnell Hill , and Section 17 mine area . U. S. Geological Survey prepared both surface and mine maps and designated the areas to be investigated ; the Bureau did the drilling , trenching, and sampling involved in the investigations . Twelve holes , aggregating 3,539 feet of bore , were diamond drilled on six properties ; 5,309 linear feet of surface trenches were bulldozed in six areas and 19 samples taken from them ; and 86 underground channel samples were cut in two adits on one property . In 1944 , the Bureau of Mines measured mine dumps and calcine dumps in the district in an investigation of their mercury content . Two mine dumps and one calcine dump were sampled . The data pertinent to the work done by the Bureau are included in this report .

Oct 1, 1950

By John A. Davis, John Gross

Six tests were made by the Alaska Station of the Bureau of Mines on a sample of black sand delivered to the station by Messrs. James, Eagan & Griffen from Fairbanks Creek, Fairbanks mining district, Territory of Alaska, to devise a method of recovering the gold content. More than 90 per cent of this black sand consisted of magnetite and garnet which can be separated magnetically. The Station has no equipment for magnetic separation other than an electromagnet similar to the one used by Day and Richards, (Day, D.T., and Richards, R.H., Investigations of Black Sands from Placer Mines, U. S. Geol. Survey, Bull. 285, 1906, pp. 150-163), which can only be used satisfactorily on small samples. To treat the entire lot of black sand with this machine would have been impracticable. Therefore only a small part of the sand was so treated, the rest being divided into five lots in order to obtain comparative results from other methods of treatment.

Aug 1, 1920

By H. D. Hess, C. P. Mabie

This report describes in detail the results of petrographic research conducted on 21 phosphate ores representing important deposits in southwestern Montana , southeastern Idaho , and northeastern Utah . The ores are described and categorized by mineralogical and chemical composition , thermal behavior of organic carbon , and textural constitution . Descriptive and genetic classification schemes applicable to western phosphate ores are discussed ; results from related studies made of the collophane mineralogy are also presented . The latter studies were centered on determining unit - cell dimensions and CO₂ , P2O5 , and fluorine content of collophane concentrates of 11 high - grade phosphate- rock hand specimens selected solely for this purpose . On the basis of this investigation , operational methods have been developed for quantitatively describing textural and compositional features that are likely to be significant in determining the response of phosphate ores to conventional beneficiation treatments ; systems for classifying the ores in relation to these features have been proposed . Studies to date point out distinct textural and compositional variations in the western phosphates and illustrate their importance in determining optimum beneficiation procedure .

Jan 1, 1964

By M. B. Cooke

 An analytical method for the determination of the gum-forming material in gasoline has been developed by the Bureau of Mines, during a study now in progress to determine the best rays for elimination of such constituents from gasoline. This method is similar in principle to that previously described by Smith and Cooke, which involved evaporation of e semple of gasoline in a small glass dish. The evaporation was started on an actively boiling steam bath and completed in an air oven at 105°C. In the improved method described below, the steam bath has been replaced by a steam heated oven in which an inert atmosphere is maintained. Air is ex- cluded from the oven, consequently the precision of the determination is increased. Furthermore, evaporating dishes different from those previously described may be used.

May 1, 1925

By Charles C. Myers, Robert M. Doerr

The apparatus described was developed for determining the kinetics of gas - solid reactions at high temperatures by measuring the volume of gas consumed with respect to time . This apparatus consists essentially of a horizontal precision- bore glass tube connecting a small reaction chamber in a furnace to a large constant - temperature reservoir . A drop of mercury in the tube separates the two sides of the system and serves as an indicator that moves at a speed proportional to the rate of gas consumption . The sensitivity of the apparatus depends inversely on both the density of the gas in the system and the cross - sectional area of the tube ; with a tube having an area of 0.079 cm² , the sensitivity for oxygen at 308 ° K and 0.5 atm is 20 cm/mg . The reproducibility of data with the volumetric apparatus is good .

Jan 1, 1964

By F. E. Griffith, C. H. SEELING

Cardox blasting is used widely in coal mines in the United States . A model of a Cardox blasting device was approved by the Bureau of Mines subject to certain conditions and limitations , and the approval was extended to other models from time to time . Certain special hazards are entailed in the use of Cardox as with explosives . One of these is flying shells . In some blasts , the Cardox shell is violently ejected from the borehole and flies like a projectile , frequently ricocheting off solid objects and striking points considerably off the line of its initial flight . Flying shells have been known to pierce the webs of structural - steel beams , to pass through both sides of allsteel mine cars , to be driven through stout hardwood timbers , to knock out timber sets , to damage loading equipment , and to break or short - circuit power lines . A considerable number of shot - firers and other workers have been struck by flying shells and killed or injured . Accidents from this cause , although not as frequent as other types of mine accidents , are usually serious , closely approximating accidents caused by blasting with ordinary explosives . The increasing number of such accidents prompted a Bureau of Mines field investigation of possible methods of preventing dangerously violent ejections of Cardox devices . This report contains pertinent data collected during the investigation and describes methods tested and discarded as well as the development and proof of an apparently satisfactory method .

Jun 1, 1943

By T. A. Henrie, E. K. Kleespies

Carbon reduction of rutile and ilmenite in nitrogen and ammonia atmospheres was studied as a method of preparing titanium nitride . Ammonia was a better nitriding agent than nitrogen . The contact between the solid reactants , carbon and rutile , was a prime factor in nitrogen atmospheres and was of lesser import in dissociated ammonia . The reduction process for conversion of rutile to the nitride required carbon . The nitriding of ilmenite- carbon mixtures produced titanium nitride and elemental iron .

Jan 1, 1964