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By Gilbert M. Farrior

The electrical resistivity the coefficient of electrical resistivity the Hall coefficient, and the absolute thermoelectric power were determined in this Bureau of Mines investigation for nine compositions of the TiB2-CrB2 sub-system. The numerical values of the electrical resistivity and the thermo-electric power were greater for the intermediate compositions than for the end members. The absolute values of the Hall coefficients and the coefficients of electrical resistivity were less for the intermediate compositions than for the end members. The electrical resistivities and Hall coefficients were about the order of magnitude of most metals--from 34 to 202 microhm-cm and from about 0 to -23.3 X 10-4 cuP/coulomb. The thermoelectric power was somewhat greater than that of most metals--up to 15.6 microvolts per 0 C.

Jan 1, 1965

By Henry M. Harris, Hal J. Kelly

Electrical dewatering tests are described in which the laboratory cells were designed for continuous operation using an endless metal belt as the anode . The test slurries were dilute , containing from 2.5 to 14.4 percent solids (specific gravity of 1.02 to 1.10 ) that were all minus 8 microns in size . Recovery of the solids of low water content was the practical objective of the investigation . Process variables evaluated and reported are : The effect of feed rate , amount of electrolyte , samples from different sources , and the use of two cells in series . These variables are evaluated on the basis of yield of clay per kilowatt - hour , recovery , and the amount of solids in the deposited clay . Recovery , yield , and solid content of the belt anode product are interdependent , and changes that will improve one of these characteristics often are accomplished at the expense of the others . Tests in which recoveries range from 50 to 60 percent usually result in yields of 8 to 9 kilograms (kg ) of dry clay per kilowatt- hour (kwhr ) . Under these conditions , the solid content of the deposited clay approximates 50 percent . One test sample , composed of kaolinite , showed very high yield , 13 to 16 kg per kwhr ; high recovery , 53 to 58 percent ; and 52 to 54 percent solids in the cake .

Jan 1, 1964

By Alvin Kaufman

Geothermal plants are competitive with conventional units. A geothermal plant can produce electric energy for 6.70 mills per kwhr, compared with 6.96 mills for coal, 6.74 mills for oil, and 7.04 mills for gas. These costs include fixed and variable charges. Potential for geothermal power exists in the Western United States, Alaska, and possibly Hawaii. Assuming that the current downward trend in cost per kilowatt of coal will cease and that the relative cost of gas and oil, already trending upward, may rise considerably more, geothermal energy will be utilized where available, in producing electric energy. It will be used in California first because it is directly competitive with gas-and oil-fired installations there. A long-term appraisal is difficult because little is known about the sources of geothermal power and the electric generating capacity which the steam fields will support. However, a market for geothermal steam-generated electricity exists within the Western States.

Jan 1, 1964

By Alvin Kaufman

Geothermal plants are competitive with conventional units. A geothermal plant can produce electric energy for 6.70 mills per kwhr, compared with 6.96 mills for coal, 6.74 mills for oil, and 7.04 mills for gas. These costs include fixed and variable charges. Potential for geothermal power exists in the Western United States, Alaska, and possibly Hawaii. Assuming that the current downward trend in cost per kilowatt of coal will cease and that the relative cost of gas and oil, already trending upward, may rise considerably more, geothermal energy will be utilized where available, in producing electric energy. It will be used in California first because it is directly competitive with gas-and oil-fired installations there. A long-term appraisal is difficult because little is known about the sources of geothermal power and the electric generating capacity which the steam fields will support. However, a market for geothermal steam-generated electricity exists within the Western States.

Jan 1, 1964

By J. A. Herdlick

The Star mine, near Neihart, Cascade County, Mont., has been in continuous operation since the construction of a 50-ton bulk flotation mill in 1939. The mine was examined by G. N. Bennett, an engineer of the Bureau of Mines, in November 1942. At that time the life of the operation appeared to be limited and a program of crosscutting and core drilling were recommended. The program had as its objective the investigation of a promising undeveloped area lying west of the Star vein and, if possible, the development of enough reserves in this area to insure continuous operation during the war emergency. Development of additional reserves would then justify necessary changes in the mill in order to eliminate the heavy penalties imposed for excess zinc in the bulk concentrates. The Bureau of Mines work began in February 1944 and was completed in September 1944. The project was started by Wilder R. Brinton and continued by Thomas W. Oster, mining engineers in the Bureau's Montana district office. Beneficiation tests on are and concentrates were made after completion of the underground work. This report presents the factual data obtained during all phases of the Bureau's investigation.

Jan 1, 1949

By R. Hogg

"The basic population balance models for agglomeration processes are reviewed and procedures are described for extending their applicability to systems with size-dependent rate constants and to the formation and growth of porous agglomerates from rigid, solid-particles. Simplified procedures for the further extension of the models to include simultaneous agglomerate growth and breakage are also described.INTRODUCTION The association of small particles into clusters or agglomerates is a significant factor in many facets of particle processing. Agglomeration processes are widely used to facilitate handling, storage and utilization of fine powders. Processes such as coagulation or flocculation are used to aid solid-fluid separation in dispersed particulate systems. Agglomeration also occurs as an accompaniment, often unwanted, to other particulate processing operations such as fine grinding, mixing and blending, transport and flow.Reliable agglomeration models are needed for improved understanding of the processes in general and of the complex role of numerous, interacting variables as well as for direct application to the design and control of industrial processes such as flocculation, granulation and pelletization. Ideally, the models should account for the primary forces responsible for agglomerate formation and growth, the effects of external forces on process dynamics, the development of agglomerate structure and its role in the process itself, and the effects of concurrent processes such as structure modification (e.g. compaction) and agglomerate breakage or degradation."

Jan 1, 1989

By M. C. Malamphy

A general description of the activities and results of bauxite investigation by the Bureau of Mines at its bauxite project in Saline and Pulaski Counties, Ark., has been given in Report of Investigations 4251. The factual data obtained during the project are reported in a series of Reports of Investigations beginning with No. 4251, of which this is the third. The data are accompanied by maps showing the location of holes drilled and deposits developed. Each area upon which work was done is reported by half townships. Each bauxite deposit investigated was assigned a name and a number for ready reference and identification, and its location and name are shown on the appropriate half-township-map. The description of each half township is followed by a description of each deposit developed in that half township.

Jan 1, 1948

By A. B. Cecala

The Bureau of Mines has developed a pallet loading dust control system designed to lower the dust exposure of workers during the bag stacking process at mineral processing facilities. The system makes bag stacking much easier because the pallet height remains constant throughout the entire bag stacking cycle through the use of a hydraulic lift table. The system uses a push-pull ventilation technique to capture the dust generated during bag stacking. A low-volume, high-velocity blower system operating at approximately 150 cfm blows a stream of air over the top layer of bags on the pallet. The blower system is composed of two 3-in air jets (approximately 1,200-ftjmin velocity) directed toward an exhaust system on the opposite side of the pallet. As these air jets travel across the pallet, they entrain the dust generated during bag stacking. The exhaust ventilation system pulls approximately 2,500 cfm of air and dust through the exhaust hood. This exhaust air can then be dumped into a baghouse ventilation system, or filtered before being discharged outside the mill. During a laboratory evaluation, a 70-pct dust reduction was recorded for the bag stacker. The system was then evaluated in an actual working environment. The first field evaluation was performed at a silica sand operation in which one worker performed the entire loading and bag stacking process. This worker's dust exposure was lowered 76 pet when using the new pallet loading system. The second field evaluation showed only moderate dust reduction, but this was mainly attributed to an overriding problem associated with background dust and the cleanliness of the bags. From both the ergonomic and production standpoint, the system was well received by both the workforce and plant management.

Jan 1, 1988

By Stanton L. Tainter

When the disruption of gold mining stopped the usual source of siliceous flux needed by copper smelters , sandstone copper deposits in northern Arizona offered possibilities as a source of the flux during the war emergency . The Federal Geological Survey , while making a comprehensive survey of sandstone copper deposits , investigated the Warm Springs mining district in northcentral Coconino County in August 1943. A month later , J. H. Hedges , chief of the Tucson Division , Mining Branch , Bureau of Mines , examined the operations in connection with an application for an access road . Both investigations concluded that the district , as an emergency source of copper-bearing siliceous flux , had considerable merit , provided high prices for copper continued in effect . Early in 1944 , V. M. Ryan and S. B. Atherley requested assistance from the Bureau in exploring various deposits on their property . The Bureau / drilled 152 holes , aggregating 3,756 feet , on the Petoskey and Mackin groups of claims . This report is based upon churn drilling done under contract from October 7 to November 25 , 1944 .

Feb 1, 1947

By McHenry Mosier

Diamond -drilling blast holes at Eastern Magnetite Mine C is proving economical in boundary shrinks , in removing pillars not readily accessible for percussion drilling , and in driving scraper drifts . The cost per foot drilled is greater than for percussion drilling , but savings in associated factors outweigh this handicap . The rocks drilled include trap rock and magnetite ore . The mining method is the panel , block- caving system utilizing scraper sublevel drifts instead of branch raises to convey the ore to the haulage level . Diamond -drilling blast holes was begun early in 1945. Three rigs equipped with noncoring bits are now in active operation two shifts per day . They are owned by the company , and the drill operators are paid by the day . In shrinkage stopes the drill is mounted on a horizontal bar set against opposite walls of the stope . Stoping holes are horizontal , which gives better results in blasting and requires fewer set ups . In scraper drifts the drill is mounted on a horizontal bar clamped to two columns about feet apart . Trim holes around the periphery of the drift and reliever holes are drilled 50 to 80 feet in length . A 10 - foot wedge cut drilled with a stoper is blasted in conjunction with a corresponding length of the trim holes to effect a 10 -foot advance of the full- sized drift . Recent drilling averages 97 feet per machine shift , excluding time utilized in setting up and moving the machine , hand mucking , and barring down . The feet drilled per bit at present is 417. These data represent the average for drilling in both rock (waste) and ore . Percussion drilling utilizes three types of wet drills . Detachable bits are standard . Gage changes for new bits is 1/8 inch and for reconditioned bits 1/16 inch . The life of a bit is five uses . Resharpening is on contract . A drill carriage is used in haulage headings .

Feb 1, 1948

By ALICE V. Petar

Among the rarest of the rare metals are four that are linked together by a common historical background as well as by chemical relationship. With the excep- tion of indium, these metals are likewise characterized by the patriotic nature of the names given them by their discoverers. The existence of gallium, germanium, and scandium, was predicted by the Russian cherist, D. I. Mendeleeff some time prior to their discovery; and these elements might well have been overlooked, had not the search been stimulated by the urge to confirm the scientific hypothesis of their existence. Nowhare found in sufficient quantities to attract attention, these little known elemente are nevertheless widely distributed in the earth's crust. So far they are found commercially mostly in the sulphide ores of zinc and must be considered as being largely curiosities of the zinc smelter. Recent progress in electrolytic zinc refining, however, now gives promise that the way may be open for the recovery of these very rare metals in larger quantities-- possibly in quantities sufficient to permit of their finding commercial utilization.

Nov 1, 1930

By Lex B. Golden

The purpose of this investigation was to evaluate the corrosion properties of certain alloys of titanium and to compare them with those of unalloyed titanium. Such information should make it possible to determine the desirability of substituting these alloys for commercially pure titanium in certain applications. Titanium-manganese, titanium-chromium-iron, and titanium-vanadium-iron alloys, with 2 types of unalloyed titanium, I consolidated by arc melting and the other by powder-metallurgy techniques, were included in the study. Tests were carried out in sulfuric, hydrochloric, phosphoric, nitric, and mixed acids and in chloride solutions. All solutions were saturated with air.

Jan 1, 1957

By Henry E. Blake

The Bureau of Mines has been engaged in a continuing research effort to develop processes for increasing the recovery and utilization of fluorine from low-grade resources. This current research has shown that over 98 percent of the fluorine in phosphate rock is extracted when the ore is treated with excess phosphoric acid in the presence of water vapor at 150° to 180° C. More than 80 percent of the fluorine can be recovered as fluosilicic acid, which can then be converted to commercially useful hydrogen fluoride or fluorspar by previously developed Bureau processes. Extraction of P205 from the ore was about 98 percent in batch tests and 90 percent in semicyclic tests.

Jan 1, 1974

By B. W. Jong

As part of the Bureau of Mines program to develop substitutes for critical and strategic materials for metallurgical applications, the Tuscaloosa Research Center has evaluated the effect of additives and starting materials on the sintering and strength properties of sialon (silicon-aluminum-oxynitride) compositions fabricated by conventional pressing and sintering techniques. Sintering and MOR (modulus of rupture) data were developed for sialon compositions produced from three components, Si3N4, A1203, and AIN. When doped with Y203 to aid in sintering, the highest MOR values were obtained with compositions containing between 20 and 30 mole-pet (A1203 + AIN). The effect of the crystalline phase of the Si3N4 and Al203 used in the three-component system on MOR also was investigated. Alpha-Si3N4 and ?-A1203 were found to be the best starting materials. A sialon composed of 67.4 mole-pct a-Si3N4 plus 32.6 mole-pct (?-AI203 + AIN), doped with 5 wt pct Y203, had MOR values at 25°, 1,200°, and 1,400° C of 40,300, 40,300, and 31,100 psi, respectively. Samples of this composition doped with Gd203, MgO, Zr02, and ZrSi04 also were evaluated. The ZrSi04-doped sialon had higher MOR values than Gd203-, MgO-, and Zr02-doped materials but lower MOR values than the Y203-doped sialon. The MOR values of ZrSi04-doped sialons were 25,000 and 25,900 psi, respectively, at 25° and 1,400° C.

Jan 1, 1981

By D. Montagna

This Bureau of Mines report describes a salt-free, fluxless method for reclaiming metallic aluminum from aluminum dross. The dross is smelted under argon, nitrogen, or carbon dioxide, instead of a salt flux, in an externally heated pot furnace. Aluminum recovery, using argon, is equal to recoveries reported from commercial smelters that process dross in rotary-type furnaces This salt-free method could offer a reduction in air pollution, lower energy requirements by elimination of salts, and the production of up to 60 percent less solid waste for disposal than the salt method.

Jan 1, 1978

By R. L. Crosby

The Bureau of Mines investigated alloys of copper with 2, 3, and 4 vol pct alumina and with 2 vol pct yttria. Alloys were prepared by a coprecipitation process and were fabricated by pressing and sintering of powders, extrusion, and swaging. Tensile properties at room and elevated temperatures, stress-rupture strength, electrical conductivity, and density were measured. The superiority in elevated temperature strength of dispersion-strengthened copper to OFHC copper was confirmed. Increasing the oxide content from 2 to 4 vol pct produced only a small improvement in strength properties and decreased the electrical conductivity. The 3 vol pet alumina alloy had the best overall combination of properties.

Jan 1, 1969

By Van E. Shaw, D. J. Bauer

Conversion of euxenite concentrate to sulfates with sulfuric acid and solvent extraction of the yttrium- rare - earth mixture with EHPA were studied to determine extraction and separation characteristics . Digestion with 3.5 pounds of 96 percent sulfuric acid per pound of concentrate at 336 ° C for 4 hours resulted in an easily handled product with a yield in excess of 98 per- A thorium- free product was obtained by calcining the sulfated material for 3.5 hours at 650 ° C prior to leaching with water . Di ( 2 - ethylhexyl ) phosphoric acid solvent is an effective extractant with preference for cerium ( IV ) and heavy - group rare - earth elements including yttrium . Separation of complex rare - earth mixtures into light- and heavy - group fractions is feasible , and these fractions can be further processed to isolate ytterbium , neodymium , and dysprosium by changing processing conditions to obtain separation factors greater than two between these and adjacent elements .

Jan 1, 1965

By R. Hogg

"The basic population balance models for agglomeration processes are reviewed and procedures are described for extending their applicability to systems with size-dependent rate constants and to the formation and growth of porous agglomerates from rigid, solid particles. Simplified procedures for the further extension of the models to include simultaneous agglomerate growth and breakage arc also described. IntroductionThe association of small particles into clusters or agglomerates is a significant factor in many facets of particle processing. Agglomeration processes are widely used to facilitate handling, storage and utilization of fine powders. Processes such as coagulation or flocculation are used to aid solid-fluid separation in dispersed particulate systems. Agglomeration also occurs as an accompaniment, often unwanted, to other particulate processing operations such as fine grinding, mixing and blending, transport and flow.Reliable agglomeration models are needed for improved understanding of the processes in general and of the complex role of numerous, interacting variables as well as for direct application to the design and control of industrial processes such as flocculation, granulation and pelletization. Ideally, the models should account for the primary forces responsible for agglomerate ·formation and growth, the effects of external forces on process dynamics, the development of agglomerate structure and its role in the process itself, and the effects of concurrent processes such as structure modification (e.g. compaction) and agglomerate breakage or degradation.In its most general form, the process of agglomeration involves taking discrete, independent particles, bringing them into contact with one another, promoting (or allowing) interparticle adhesion to occur and then causing structure rearrangement, usually under the action of external forces. The relative importance of these steps varies with the nature of the particulate system being agglomerated and with the kinds of agglomerates being produced. Coagulation or flocculation of particles dispersed in fluids is generally dominated by the contact and adhesion steps. In the granulation of powders, on the other hand, particles are already in contact so that structure rearrangement is the principal step."

Mar 1, 1992

By R. V. Lundquist, A. E. Morris, E. L. Singleton

This experimental research was performed to determine rate - of - reaction constants on the MnO - C and Mn , C₂ - 3MnO systems at 1,100 ° , 1,150 ° , and 1,185 ° C. Reactions were conducted at atmospheric pressure under controlled flow of purified helium through the furnace chamber . The weight - loss method defined reduction percentages , and reaction products were identified by X- ray methods . The system Mn0 - C followed a linear reaction rate , and experimental results produced an apparent activation energy of 55.8 kcal per mole of Mn0 . The system Mn, C - 3Mn0 followed a parabolic rate of reaction law and yielded an apparent activation energy of 114.4 kcal per mole for the reaction .

Jan 1, 1964

By Thomas M. Garland

A field study was made by the Bureau of Mines in cooperation with oil companies to determine the feasibility of changing the injection profile of water-input wells after water breakthrough at producing oil wells. A secondary objective was to study the particle size and quantity of plugging material required to change the input profile and the methods of applying these materials. Fifty-three injection wells were treated with various amounts and types of plugging materials and the injection profile was definitely changed in most of the wells treated. Increased efficiency of water injection after treatment was indicated by tracer surveys and injection-well performance. There were some indications that the rate of water production was reduced and the rate of oil production was increased as a result of selective-plugging treatments, but ,s found that an immediate change in the rate of oil and water production did not normally occur. In many cases, beneficial results from a treatment may never be observed in the rate of oil or water production due to the many factors that affect the performance of producing and injection wells.

Jan 1, 1966