Search Documents

By D. W. Bridges, S. R. Borrowman

Thorium and yttrium oxides were recovered from siliceous ores of the Powderhorn , Colo . , area . Processing comprised ( 1 ) acid curing and subsequent ( 2 ) acid baking , ( 3 ) leaching , and ( 4) solvent extraction of thorium , using a primary alkylamine , and yttrium , using di - 2 - ethylhexyl phosphoric acid . About 95 pct of the contained thorium and yttrium was recovered from ore containing 1.2 pct Th02 and 0.5 pct Y₂ 03. The thoria product was 99 pct Tho ; the yttria product was 77 pct Y₂ 03. A 150 - to - 1 concentration ratio was effected on the latter , but some contaminating lanthanon - group oxides remained .

Jan 1, 1964

By Jr. Norman

The Bureau of Mines investigated the thermoelectric properties of yttrium selenides and tellurides from room temperature to 900° C. X-ray crystallographic data were determined for the yttrium-selenium and yttrium-tellurium compounds that were orthorhombic with a cubic substructure. The yttrium selenides and tellurides exhibited semimetallic to insulator conduction properties with figures of merit of 10-9 to 10-4 °C-1. The mono-selenide and monotelluride behavior was partially degenerate; unsatisfied bonds were the source of the large number of charge carriers. The higher stoichiometry selenide compounds were intrinsic semiconductors) but with high electrical resistivities. A critical defect or impurity ionization energy for carrier activation appeared to exist in the majority of telluride compounds. Mobility and energy band determinations are required to interpret completely the observed effects in most of the compounds studied.

Jan 1, 1966

By Bertrand L. Johnson

Langbeinite, a comparatively rare mineral that has been reported from only five countries in the entire world, has recently attained considerable economic importance in the United States and Poland. Since September 1940, several hundred thousand tons have been produced in one of the Carlsbad (N. Mex.), potash mines for chemical and fertilizer use. As it is a newcomer in this field, and as it is the source of fertilizers possessing special advantages, notably for soils deficient in magnesium or requiring sulfate fertilizers, a discussion of its properties, occurrences, uses, mining, and treatment is appropriate at this

Jan 1, 1944

By E. K. Kleespies

The rate of the heterogeneous reaction between titanium-oxygen solid solutions and titanium trichloride in molten sodium chloride was determined at high temperatures. In the alpha phase, the reaction rate decreases uniformly with the increasing concentration of oxygen. The gamma crystalline form of titanium (above 33 atomic percent oxygen) was much less reactive than the alpha phase, and the reaction rate approached zero at 50 atomic percent oxygen. The activation energy for the reaction of titanium-oxygen solution containing 22.8 percent oxygen was 11.7 kcal/mole of TiCl3 as compared with 8.3 kcal/mole of TiCl3 for pure titanium.

Jan 1, 1967

By J. M. Stuve

Low-temperature adiabatic heat-capacity determinations were made by the Bureau of Mines in the temperature range from 5 to 300 K for the two crystalline modifications of zinc sulfide, sphalerite (ß) and wurtzite (a). The entropy at 298.15 K of sphalerite was evaluated as l4.02±0.04 cal/deg mole and wurtzite, l4.06±0.04 cal/deg mole.

Jan 1, 1974

By J. H. Stears

This Bureau of Mines report presents information on the use of steel supports in U.S. coal mines, including accident statistics for a 3-yr period and a survey of present applications and problems. It also contains a summary of available steel arch configurations and a description of steel support design criteria for ground control applications.

Jan 1, 1984

By W. A. Cole

Underground mining methods at the Gray mine of Tri-State Zinc, Inc., are of special interest because of the low unit costs achieved through use of jumbos and loading equipment mounted un crawler-type tracks and of diesel trucks that haul from the stoping areas to the mill through inclined adits. The operating company, Tri-State Zinc, Inc., is a wholly owned subsidiary of Gold Fields American Development Co., Ltd., the latter being the American branch of New Consolidated Gold Fields, Ltd., a British-owned company.

Jan 1, 1957

By Larry L. Anderson

Enormous quantities of organic wastes are produced each year in the United States. The total amount is in excess of 2 billion tons and at least 880 million tons of this is moisture- and ash-free organic material (dry organic solids), representing a potential energy source of significant magnitude that is not being utilized. Bureau of Mines scientists have developed methods for converting these wastes to convenient energy forms. This report itemizes and evaluates for the first time in detail the quantities and sources of moisture- and ash-free organic material contained in manure, urban refuse, industrial wastes, sewage solids, and agricultural wastes in the United States. Furthermore, estimates are presented for amounts of organic wastes collected or concentrated. The potential for fuel, either oil or gas, from both the total organic wastes generated and those collected or concentrated is also estimated.

Jan 1, 1972

By C. L. Klingman

The Bureau of Mines tested eight commercially available, activated charcoals experimentally to compare the following characteristics: capacity for adsorption of nitrogen at 77° K and 170 atmospheres' pressure, surface area, carbon tetrachloride adsorption capacity, hardness, and density. The nitrogen adsorption test was devised to simulate plant conditions occurring in the final step of purification in Bureau helium faciliti.es. The remaining tests were patterned after empirical acceptance tests that are widely used throughout the adsorbent industry. Surface area and carbon tetrachloride adsorption correlated well with nitrogen adsorption. The samples with low density generally had better adsorption qualities than those of higher density. The carbon tetrachloride test appeared to be the most practical for selecting a charcoal to be purchased, but an attrition, or hardness test should also be run to be sure the charcoal will not crumble in use.

Jan 1, 1966

By V. E. Edlund

Laboratory batch flotation tests were conducted on copper converter slags to evaluate the relative merits of recovering copper from slow-cooled versus water-quenched slags. Three slags containing 1.6, 5.0, and 6.6 percent copper were used. More than 90 percent of the copper was recovered in a rougher concentrate leaving a 0.2- to 0.3-percent copper tailings when treating slow-cooled slag. Lower recoveries and higher copper tailings ranging from 0,5 to 0.6 percent copper were obtained from quenched slag. Grindability studies were made on the respective heat-treated slags. Quenched slags proved more difficult to grind than slow-cooled slags. Cost studies showed that (1) the cost of slow cooling and crushing off-sets any advantages of higher copper recoveries from slow-cooled slag, and (2) water-quenched slag, which requires no crushing preparatory to grinding, could be treated more economically. Costs based on processing 1,000 tons of slag per day would be $1.85 per ton for quenched slag versus $2.37 per ton for slow-cooled slag.

Jan 1, 1971

By Jerry E. Olson

In 1988, at the request of the Bureau of Land Management, the U.S. Bureau of Mines studied additional areas, encompassing 11,303 acres, on the east and west sides of the 20,727-acre Badlands study area (Olson, 1987) in order to evaluate their identified mineral resources. The Badlands study area additions are located in Crook and Deschutes Counties, OR, about 10 and 18 miles east of Bend, OR. No mineral resources were identified. The additional areas studied are underlain by Tertiary-and Quaternary-age basalt flows which are largely covered by a veneer of sand and silt. No mines, prospects, mining claims or mineralized areas occur within or near the Badlands study area additions. Slab lava of marketable grade and quantity was not found in either area. None of the study area is of current interest for geothermal resources, but the eastern study area addition has been leased (1984) for oil and gas.

Jan 1, 1989

By James H. Russell

The Bureau of Mines used a statistical approach to evaluate the effects of temperature, current density, and composition of the electrolyte on the purity of boron prepared by electrolysis of a fused mixture of boric oxide in potassium fluoborate. The quadratic equation which best fits the data was calculated for a temperature of 650° to 850° C, a cathode current density of 40 to 1,150 amp/ft2,and a boric oxide content of 0.3 to 7.1 molal. The best products, better than 95 percent boron, were obtained when the current density was less than 2 amp/ft2 and the boric oxide content was less than 2 molal.

Jan 1, 1967

By D. R. Tesarik

To ensure the stability ofa tailings pond embankment, the height of the phreatic surface must be kept at or below a safe level. In this investigation, the Bureau of Mines analyzed various horizontal drain designs for tailings embankments to determine their effects on location of the phreatic surface. This report describes the investigation, and it includes 21 dimensionless graphs that can be used to estimate the drain spacing and length dimensions necessary to ensure the stability of embankments of various configurations. Analyses were based on the use of two computer codes, a three-dimensional finite-element code and a two-dimensional finite-difference code. The computer-generated results were compared with results obtained from a laboratory embankment model, other laboratory test results, and piezomet-ric data from two actual tailings embankments. Nearly the same phreatic surface locations were predicted using either of the computer codes. For one of the actual embankments studied, the predicted phreatic surface location was slightly higher than the measured location; for the other, the predicted location closely followed the actual surface trend. Phreatic surfaces of the laboratory model were slightly higher than the code-gener-ated locations, and the differences grew larger as drain length increased or drain spacing decreased.

Jan 1, 1984

By Diana K. Schimmelpfennig

Assessment of revegetation success on mined lands is a difficult, time consuming task and has been the subject of a number of controversies. Present regulations require that both plant cover and aboveground plant biomass be measured for use in making that assessment. Of these two variables, biomass is the most time consuming to measure and requires destructive sampling, a most undesirable requirement on fragile, recently revegetated areas. On the other hand, plant cover can be estimated using the point-frame method which is relatively nondestructive. In addition, vegetation can be sampled more uniformly with the point frame and in less time if species composition measures are to be made. A study was done to evaluate the predictability of aboveground biomass production on revegetated mined sites and adjacent native prairies using plant cover estimates made with the point frame method. The predictability of biomass production by cover estimates bears on the need for both measurements in assessing revegetation success. In general, a positive, statistically, significant correlation was demonstrated between plant cover (estimated by the point frame) and aboveground biomass (estimated by the harvest method) regardless of community type (mined or native), species composition, diversity or level of biomass production. However, the latter did have their effects on the relationship and must be accounted for in any predictive equations (that is to say, the predictive equations must be considered site-specific). Considering the relationship observed between the two parameters, cover estimation may be a sufficient indicator of revegetation success, especially where time and minimization of disturbance are critical.

Jan 1, 1982

By A. Gene Collins

This report discusses some of the chemistry and geochemistry of cesium and rubidium. Knowledge of the cesium and rubidium content of oilfield waters aids in resolving the origin of waters and petroleum, exploring for petroleum and other valuable minerals, discovering water pollution sources, and augmenting the knowledge of geologic formations. The methods described in this report permit the detection of less than 0.01 mg/l of cesium and/or rubidium in a complex oilfield brine or water. Solvents possessing high-dielectric constants were evaluated for their ability to extract cesium and rubidium tetraphenylboron from oilfield waters and for their flame emission characteristics. Nitroethane was selected and used for the extraction and flame spectrophotometric determinations because it gave the highest sensitivity. Cesium 137 and rubidium 86 were used to determine the extraction efficiencies, which were about 87 percent and 58 percent respectively using a single 10 ml nitroethane extraction from a distilled water matrix. The standard deviation of the determination was 0.0008 mg for cesium and 0.0007 mg for rubidium in the 0.01 mg range.

Jan 1, 1965

By W. S. Sanner

Seven samples were analyzed from the major reserves of the Bottom Red Ash bed, Northern anthracite field. The data show variations in thickness and geo-logic structure and in the amount of coal that can be recovered. Recovery of market-grade (less than 17 percent ash) coal is high for all samples, ranging from 76 tp 95 percent in the 3-1/4-by 9/16-inch sizes. The occurrence of coal containing less than 5 percent ash varies from 19.5 to as much as 57.5 percent. Crushing the coarse sizes to minus 9/16 inch increased recovery of market-grade coal in six of seven bed samples. Crushing released sufficient impurities to cause substantial increases in yield of coal containing less than 5 percent ash for all samples. Analyses of the float coal indicate that the quality of coal is comparable for all samples.

Jan 1, 1967

By A. L. Engel

High extractions of lead, gold, and silver resulted from treatment of an oxidized, arsenical refractory ore by chloride volatilization. The ore was roasted in an oxidizing atmosphere at 1,000° C. for 1 hour. The chloridizing reagent was 300 pounds of CaC12?2H20 per ton of ore. Ninety-nine percent of the lead, 98 percent of the gold, and 96 percent of the silver, and only 6 percent of the arsenic, were volatilized. These results indicated that a satisfactory method could be developed for treating this type of ore. Recovery and separation of the volatilized values and developing metallurgical and operating data for this process require further investigation on a more extensive scale. Tests by gravity concentration, flotation, and cyanide leaching did not give satisfactory results.

Jan 1, 1958

By C. A. Komar

The Bureau of Mines is investigating possible applications of acoustic energy at sonic and ultrasonic frequencies in petroleum production. A phase of this work involves measuring sound velocity through petroleum reservoir rocks. References and abstracts were prepared as a bibliography to make available to others some of the material obtained from a literature search covering the past applications and the present uses of sound. Laboratory and theoretical studies of the various parameters that influence the velocity of sound in porous media account for the wealth of information now available. Velocity of propagation of sound waves in porous sediments as a function of depth is a quantity frequently measured. Velocity logging systems, capable of measuring speed of sound waves in underground formations penetrated by wells, have been developed for interpretative studies. The close relation between acoustic velocity and porosity makes it possible to determine porosity from velocity logs. Most velocity log interpretation in terms of porosity is based on a formula developed by Wyllie and others known as the time-average relation.

Jan 1, 1963

By V. A. Nieberlein

The purpose of this investigation is to determine the reserves of columbium (niobium) minerals in Arkansas and to develop metallurgical methods for concentrating the minerals and extracting the metal. The columbium resources of central Arkansas were explored by drilling and trenching, and a number of samples were taken. On the basis of this exploration the known reserves of the metal were estimated to be over 78,000,000 pounds. The reserves could possibly be extended by additional exploration to 150,000,000 pounds.

Jan 1, 1954

By K. A. Fowler, L. W. Higley

The effect of uranium on the transformation kinetics and the hardenability of a low- alloy steel was evaluated . Isothermal transformation curves were developed from metallographic studies , and hardenability was determined by standard Jominy end- quench tests . For the steels investigated , the addition of 0.15 weight- percent uranium was found to produce a significant shift in the isothermal transformation curve and caused a related increase in hardenability . These effects diminished rapidly when the uranium content was increased above 0.2 weight - percent .

Jan 1, 1964