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By Howard J. Pincus

The purpose of the study is to investigate the effects of fracture filling and associated alteration on the mechanical behavior of rocks. Results are presented for specimens from the Climax and Henderson mines in Colorado and the San Manuel mine in Arizona. The rock types studied from each location are from 1) Climax, medium-grained - granite, fine-grained granite, granite porphyry, schist, and gneiss; 2. Henderson, rhyolite porphyry; 3. San Manuel, quartz monzonite and quartz monzonite porphyry. A description of the rocks was made including: color, texture, mineral composition, composition and fabric of fracture fillings, density and porosity. Unconfined and triaxial compression tests were run on the Climax and San Manuel specimens. Sonic relocities were measured during the compression tests; Shore sceleroscope hardness was measured before the compression tests. Tentative conclusions are that some relation appears to exist between compressive strength and the following properties and features for all the specimens: dynamic Young's modulus, sonic velocity, density, rock composition, and composition and fabric of fracture fillings - veinlets. There appears to be some relation between compressive strength and Shore scleroscope hardness and porosity for quartz monzonite (San Manuel). A relation appears to exist between compressive strength and texture for schist and between com¬pressive strength and extent of failure on fracture fillings for fine-grained granite, schist, and gneiss (Climax). We plan to perform additional analyses of data collected so far and data yet to be collected in the next few months, with emphasis placed on devising a practical index of alter¬ation that can be used in the field. Limitations on interpretations arise from such factors as heterogeneity of the rocks studied, the small range of confining pressures used, and other factors presented in the text.

Jan 1, 1973

By F. W. Horton

Investigation of an extensive deposit of chromite-bearing actinolite-talc schist situated on the summit of Casper Mountain, 10 miles south of Casper, Wyo., was one of the first projects Undertaken by the Bureau of Mines under the Strategic Materials Act (Public 117, 76th Cong., Ch. 190, 1st sess.), for which an appropriation became available August 9, 1939. During the previous summer; the Geological Survey? made? a magnetometrical survey of the area in which the schist occurred. It was exposed in several small lenses and two larger ones aggregating about 19?acres in area. Although the occurrence of chromite here had been known for many years, the only work done on the deposit was the digging of? a few shallow pits on some of the more promising outcrops. From August 23 to December 3, 1939, the Bureau of Mines investigated the larger of the two main schist bodies. Twenty-four trenches having a total length of 8,073 feet were dug across the deposit, and its subsurface extension was explored by 3,623 feet of diamond drilling. Over 32 tons of samples were shipped to the Metallurgical Division of the Bureau of Mines at Reno, Nev., for reduction, analysis, and ore testing. In all, there were 853 individual samples. Geological maps, based upon examination of outcrops, trenches, and drill cores, as well as a contour map of the area were made by the Geological Survey.

Jan 1, 1949

By P. B. Altringer

Searles Lake, CA, contains the largest known domestic tungsten resource. The brines in this near-dry lake bed, located in the Mojave Desert 130 mi northeast of Los Angeles, contain an estimated 135 MMlb of tungsten. However, the low concentration of tungsten (0.080 g/L W03) in the supersaturated brine makes selective tungsten extraction very difficult. Although many brine chemicals are extracted from the lake, tungsten recovery was an elusive goal prior to Bureau of Mines development of an ion-exchange technique. This publication describes the Bureau process. The following subjects are ad-dressed: ? The Searles Lake tungsten resource. ? General problems associated with tungsten recovery. ? Bureau research objectives. ? Synthesis of ion-exchange resins. ? Development of a two-stage ion-exchange tungsten extraction and concentration procedure. ? Product recovery and purification. ? Economic evaluation. Flowsheets for recovering three products (calcium tungstate, sodium tungstate, and tungstic oxide) are presented and evaluated, as well as a summary of the research effort and potential applications.

Jan 1, 1985

By D. C. Dahlin

The Bureau of Mines has investigated podiform chromite deposits in three ultramafic bodies in the Caribou Mountain and lower Kanuti River areas of central Alaska. The investigation, reported in two parts, was done as part of the Bureau's mission to help insure an adequate supply of minerals to meet the Nation's needs. Part I describes an extensive field investigation and mineralogical studies by personnel from the Bureau's Alaska Field Operations Center. This report, part II, describes the mineralogy of 11 samples that were high-graded from surface exposures at 10 sites and presents the results of laboratory batch beneficiation tests designed to concentrate the chromite. The 11 samples, peridotites and chromitites that consisted of variable amounts of chromite or chromium-bearing spinets, olivine, and serpentine, were beneficiated by grinding and sizing, gravity concentration, and electrodynamic separation. Three high-chromium chromite concentrates, two high-iron chromite concentrates, and one high-aluminum chromite concentrate were produced. Three other concentrates were marginal, and two were submarginal. Chromium recoveries ranged from 54 to 92 pct. These results indicate that the areas may be significant chromium resources. Potential platinum association with the chromite was also investigated. Analysis of these 11 samples indicates that the areas are not good platinum resources.

Jan 1, 1983

By John C. Edwards

Standard smoldering and flaming combustion tests using smaIl coal samples have been developed by the U.S. Bureau of Mines as a method to evaluate the response of a smoke detector. The tests are con-ducted using a standard smoke box designed and constructed according to Underwriters Laboratories. The tests provide a standard, easily reproducible smoke characteristic for smoldering and flaming coal combustion, based upon a comparison of the smoke optical density and the response of a standard ionization chamber to the smoke. With these standard tests, the range of threshold limits for the response of a smoke detector and the detector's reliability can be evaluated for nearly identical smoke visibility and smoke physical characteristics. The detector's threshold response limits and reliability need to be well defined prior to the instrument's use as part of a mine fire warning system for improved mine safety.

Jan 1, 2010

By Almon F. Robertson

"INTRODUCTION AND SUMMARYThis is one of a series of reports describing investigations within the Missouri River Basin in Montana conducted by mining engineers of the Bureau of Mines, Minerals Division, Region II. The primary purpose of these investigations is to provide basic information to agencies of the Department of Interior and others concerned with the planning of power and other water developments in the basin. This report contains only such factual data as have been authorized for public distribution. Special precautions have been taken not to reveal any information or data that are considered confidential.The field investigations for this report were made during the summer of 1949. Virtually all known metallic mineral deposits in the county and same nonmetallic (industrial) mineral deposits were investigated. Most of the mines and prospects have been inactive for many years. The old underground workings generally are only partly accessible; many are entirely inaccessible. Most of the mining claims were located many years ago, and a considerable number were patented. Many claims were abandoned; others were relocated. Nimes and ownerships often have changed. Because of such conditions, much of the information on most of the mines and prospects necessarily has been obtained from available Federal and State publications, private geologists' and engineers' reports, and from owners and local residents.Metal mining in Cascade County, Mont., has been confined mainly to the silver-lead-zinc deposits in the Montana (Neihart) and Barker districts in the southeastern part of the county. The Neihart district has yielded by far the greater part of the county's metal output. The mines generally have been operated intermittently, largely because of fluctuating or low silver and base metal prices."

Feb 1, 1951

By Richard J. Leary

The inputs of capital and labor to support future iron ore production were developed by the Bureau of Mines from projections of iron demand and estimates of capital and labor requirements. Trends in technologic change and the organization of production were analyzed. Labor requirement schedules for iron ore mining and beneficiating were constructed from aggregate inter-temporal trends and 1970 cross-sectional analysis of mines and mills. A sup-ply schedule of the capital requirement for mine-mill-pellet plants was developed from U.S. and Canadian experience. The structure of demand for iron to the year 2000 was examined as well as the availability of resources. Projections of capital and labor requirements to 2000 were constructed under two international patterns of iron ore supply to the United States. The most likely model is for a continuation of the 70 percent United States-30 percent foreign shares, expanding at an average 2.0 percent growth rate to 2000, and supported by a cumulative gross capital investment of $3.8 billion constant 1967 dollars and a labor force in the United States of 29,800 by 2000. The information content of projections is discussed, and the possible effects of international forces on supply are considered. A generalized methodology for estimating capital and labor requirements in other mineral industries also is included.

Jan 1, 1975

By R. B. Ladoo

"Present Situation:At the beginning of 1920 a general feeling of optimism was noted in many talc-producing districts. The industry seems to have recovered from the temporary depression of the first half of 1919 and many mills are running at capacity production with their entire output for 1920 contracted for. The imports of talc for 1919 were only slightly larger than in 1918 by weight and probably no more by value. Thus foreign competition has not begun to be seriously felt. Several new companies in this country have been organized, some to operate new deposits and others to continue the work done by others.An interesting phase of the present situation is the possibility of increased use of talc in paint. There is a shortage of barium sulfate used as a paint filler. Since, for some uses, talc is considered second only to BaSo4 as a filler for paint, it is possible that part of the shortage could be relieved by an increased use of talc.A series of physical tests upon all pigment materials used in the manufacture of paints is being conducted for the Paint Manufacturers Association of the United States. It is important that all types of talc be represented in these tests. Producers of finely ground talc, 200 mesh and finer, are urged to submit samples of at least two pounds each of these grades that are available to paint makers with trade name and quality data, to the Institute of Industrial Research, 19th & B Streets, N. W., Washington, D. C., where the tests are being conducted."

Jan 1, 1920

By W. H. Hamilton

The Kokomo (Tenmile) mining district has had an output valued between $20 and $30 million, mostly from production of silver, lead, and zinc, since 1878. For many years before World War II, there was little production, as the complex nature of the ores made them unattractive at existing metal prices. Under the stimulus of the war, the Geological Survey and the Bureau of Mines studied they district, and in October 1944 the Bureau of Mines began an exploration project, which included dia¬mond drilling, bulldozer trenching, and geophysical surveying. Project work was continued until March 1949, except for short recesses during 1945, 1947, and 1948. Forty-five diamond-drill holes, totaling about 13,000 feet, were drilled from underground and surface stations on the various properties in the district. Eleven bulldozer trenches, abut 2,400 linear feet, were excavated in an attempt to uncover the outcrop of the middle Quail limestone. These trenches ranged from 100 to 485 feet in length and reached a maximum depth of 15 feet. A limited geophysical investigation was made during the summer of 1946. The length of the traverses were: Magnetic, 990 feet; resistivity, 6,250 feet; and self-potential, 69,780 feet.

Jan 1, 1955

By Robert H. Peters

Groundfall accidents have been the leading cause of fatalities in the underground coal mining industry for many years. Statistics from the Mine Safety and Health Administration (MSHA) indicate that approximately half of the victims of these fatal accidents were in an area where no devices had been installed to support the mine's roof. This report was prepared by the U.S. Bureau of Mines to summarize the opinions of 268 coal miners, 29 rust-line supervisors, and 30 MSHA inspectors concerning why people go under unsupported roof, and how to prevent this behavior. Interviews were conducted at six minesites.

Jan 1, 1991

By M. M. Gilkey

This report on water requirements for the New Mexico mineral industry includes data on industrial operations closely related to mineral production. It contains general information concerning public water supplies at five principal cities and a short discussion of water needs for agriculture. Background data are presented regarding the geography, hydrography, and water laws of New Mexico, as well as precipitation and evaporation characteristics of the State. Most of the information on source, quantity, distribution, cost, and treatment of water was obtained in interviews with company representatives. Water systems at 46 operations are illustrated by schematic waterflow diagrams. The study revealed that the New Mexico mineral industry in 1962 used about 16 billion gallons of new water and reused 152 billion gallons, a total usage of 168 billion gallons. Consumption amounted to 7.6 billion gallons. Of the 16 billion gallons of new water, 11.9 billion gallons was "self- supplied" from ground water sources, and 2.6 billion gallons was self supplied from surface sources. Approximately 1.5 billion gallons was purchased. Some of the water from company-owned wells is piped as far as 30 miles. Reported costs of the self-supplied new water range from 1 to 20 cents per 1,000 gallons and average 8 cents per 1,000 gallons for power and maintenance. Inadequacy of the supply of new water at many operations necessitates large-scale recirculation. Reported costs for recirculating water (power and maintenance) average 1.8 cents per 1,000 gallons. For the entire New Mexico mineral industry in 1962, the value of product was $42 per 1,000 gallons of new water intake and $88 per 1,000 gallons consumed. Analyses of 40 water samples, listed in the appendix, show the wide range in water quality at plants throughout the State. Projection of the 1962 water requirements of the mineral industry indicate that the total demand for new water will increase from the 16 billion gallons used in 1962 to 24 billion gallons in 1980, a 50 percent increase; and to 36 billion gallons in 2000, which is 125 percent more than the 1962 intake of new water.

Jan 1, 1965

By M. M. Gilkey

This report on water requirements for the New Mexico mineral industry includes data on industrial operations closely related to mineral production. It contains general information concerning public water supplies at five principal cities and a short discussion of water needs for agriculture. Background data are presented regarding the geography, hydrography, and water laws of New Mexico, as well as precipitatton and evaporation characteristics of the State. Most of the information on source, quantity, distribution, cost, and treatment of water was obtained in interviews with company representatives. Water systems at 46 operations are illustrated by schematic waterflow diagrams. The study revealed that the New Mexico mineral industry in 1962 used about 16 billion gallons of new water and reused 152 billion gallons, a total usage of 168 billion gallons. Consumption amounted to 7.6 billion gallons. Of the 16 billion gallons of new water, 11.9 billion gallons was "self- supplied" from ground water sources, and 2.6 billion gallons was self supplied from surface sources. Approximately 1.5 billion gallons was purchased. Some of the water from company-owned wells is piped as far as 30 miles. Reported costs of the self-supplied new water range from 1 to 20 cents per 1,000 gallons and average 8 cents per 1,000 gallons for power and maintenance. Inadequacy of the supply of new water at many operations necessitates large-scale recirculation. Reported costs for recirculating water (power and maintenance) average 1.8 cents per 1,000 gallons. For the entire New Mexico mineral industry in 1962, the value of product was $42 per 1,000 gallons of new water intake and $88 per 1,000 gallons consumed. Analyses of 40 water samples, listed in the appendix, show the wide range in water quality at plants throughout the State. Projection of the 1962 water requirements of the mineral industry indicate that the total demand for new water will increase from the 16 billion gallons used in 1962 to 24 billion gallons in 1980, a 50 percent increase; and to 36 billion gallons in 2000, which is 125 percent more than the 1962 intake of new water.

Jan 1, 1965

By D. E. Shanks

The Bureau of Mines surveyed a variety of inorganic ion-exchange materials to determine their suitability for removing valuable accessory elements and troublesome contaminants from metallurgical process and waste streams. Most of the materials, which included molecular sieves, heteropolyacid salts, and hydrous metal oxides, did not give adequate separations, did not have the necessary stability in strong acids or bases, or were not in a physical form suitable for ion-exchange use. Many of the suitable inorganic materials, especially the hydrous oxides, were capable of cation exchange with high capacity only in basic conditions, which caused hydrolysis of most of the cations tested. Multivalent anions, such as arsenate and phosphate, were easily removed from acidic solutions by hydrous oxides. Hydrous zirconia was the best material for this purpose. Multivalent anions were not easily des orbed because of compound formation; therefore, conventional ion-exchange techniques could not be employed. As an alternative approach, hydrous ferric hydroxide was used as a filter material to remove arsenate and phosphate from acid solutions. One gram of arsenic was removed from solution for each 20 g of ferric hydroxide. Ferric hydroxide is preferable to hydrous zirconia for use as a filter material because of low cost.

Jan 1, 1983

By Joseph A. Cavallaro

This report describes the timed release analysis technique that was developed to serve as a tool for assessing the froth flotation cleaning potentials of fine-size coals. Using this developed technique, 16 coals from 10 different coalbeds were tested. All of the coals included in this study were quite amenable to froth flotation with float coal yields ranging from 80.7 to 99.5 percentage points. Float-and-sink analyses of the coals tested are shown to be of limited value in predicting froth flotation cleaning potential. Generally the float-and-sink analyses indicated a better product could be obtained than froth flotation could provide; although, in four of the coals tested froth flotation results were superior to those expected from the gravimetric analysis. The fixed carbon content of the samples collected was found to correlate with the floatability of the coals. The higher rank coals were the most readily floatable coals while the lower rank coals did not respond quite as well to flotation.

Jan 1, 1965

By D. W. Bridges, Donald R. Peterson, Masami Hayashi

Techniques are described for recovering about 80 pct of the cobalt and nickel contained in superalloy scrap by anodic dissolution of the scrap and simultaneous electrodeposition of a pure cobalt - nickel alloy at the cathodes in an electrolytic cell partitioned by permeable diaphragms into separate anode and cathode compartments . Superalloy scrap was alternatively prepared for subsequent anodic dissolution either by melting and casting massive scrap into suitably sized anodes , by packing moderate - sized discard scrap in inert metal baskets that subsequently served as anodes , or after concentrating the superalloy portion of grinding debris , by magnetic separation to reject corundum or other abrasives , slagging any remaining abrasives from molten grindings , and finally casting the superalloy metal into anodes . In the processing , purified electrolyte -- 1 N in NiSO4 and in NiCl₂ , and 0.1 N in CoSO4 and in CoCl2 --was charged to the cathode compartments and discharged from the anode compartments at a rate sufficient to overcome the backward migration of ionic impurities from the anodes to the cathodes . Discharged electrolyte was purified by reacting it first with SO2 and next with limestone , and then recirculated to the cathode compartments , in which a 50 pct cobalt - 50 pct nickel alloy was deposited on either blanks of stainless steel or starting sheets of cobalt - nickel alloy . The process was made self - sustaining by either adding H2SO4 to the catholyte feed to throttle the rate of cobalt - nickel deposition , thereby compensating for the slower rate of cobalt - nickel dissolution from the anode and losses occurring in electrolyte purification , or alternatively , adding H₂SO4 to

Jan 1, 1964

By Wilson Blake

This report presents the results of a 7-year Bureau of Mines program to review, revise, and make an effective engineering tool of the microseismic method of determining the stability of rock structures. The program consisted of developing new microseismic equipment and data analysis techniques and extensive field investigations to demonstrate the effectiveness and potential of the broad-band microseismic method. The guidelines for choosing the components of a microseismic system are presented along with approximate cost figures. Different microseismic systems are discussed, including completely automated systems. Procedures for conducting microseismic investigations and analyzing microseismic data are discussed in detail. Field situations which show the full value of the microseismic technique as an engineering tool are described.

Jan 1, 1974

Alabama ranked 19th in the Nation in nonfuel mineral value1 in 1994, down from 18th in 1993, according to the U.S. Bureau of Mines. The estimated value for 1994 was $576 million, a 2.5% increase over that of 1993. This followed a 3.5% increase in 1993 over that of 1992. The State accounted for a little less than 2% of the U.S. total. Nonfuel mineral production in Alabama consisted entirely of industrial minerals; no metals were mined in the State. Bauxite materials mined in the State are a natural mixture of bauxitic clay and bauxite having very low iron oxide content and are primarily used to make refractory (high temperature resistant) products, rather than in the production of primary aluminum. In descending order of dollar value, the top four mineral commodities produced in Alabama were crushed stone, portland cement, lime, and construction sand and gravel. These commodities accounted for almost 88 % of the State's total non fuel mineral value, while crushed stone and portland cement together represented almost 65 % of the total. In estimated mineral production for 1994, Alabama remained first in common clays and first of only two States that produced bauxite; third in lime, kaolin clays, and fire clays; seventh in portland cement and salt; and was one of the top seven States that produce bentonite clays. The State dropped from third to fifth in masonry cement. Production of talc and pyrophyllite resumed in 1994. Compared with 1993, the value of crushed stone, lime, construction sand and gravel, common clays, kaolin clays, fire clays, bauxite, and talc and pyrophyllite increased. Decreases occurred in portland cement, masonry cement, industrial sand and gravel, and dimension stone.

Jan 1, 1995

By John F. Wiss

A series of controlled experiments was conducted at four surface coal mines to study the effects of certain blast parameters upon the ground and air vibration. Preliminary scale-model blasts were conducted at a quarry to provide basic data. It was found that the amplitudes of the ground and air vibration were controlled by the maximum explosive weight per delay. Either cube root or square root scaling could be used for the seismic amplitudes, and cube root scaling could be used for the overpressure amplitudes. Both amplitudes were not significantly affected by the total charge weight per blast, the attitude of the boreholes, or the charge length or diameter. The overpressure amplitudes were affected by the charge depth, the use of cover over surface detonating cord, and the use of adequate stemming. The length of the delay intervals and the spacing of holes were important in determining the potential for reinforcement of the amplitudes in certain directions from the blasts. In downwind directions from the blast, the attenuation of the overpressure with distance decreases. Surface terrain did not significantly affect the overpressure amplitudes within the range investigated. The type of overburden affects the generation of both amplitudes and the propagation of the seismic amplitudes. Spectral analysis of the ground and air vibration is reported. A bibliography of pertinent literature is included as an appendix. A scaled distance of 300 ft/lb1/3 should produce a peak particle velocity of less than 1 ips and an overpressure of less than 128 dB linear peak. For square root scaling, a scaled distance of 75 ft/lbl/2 should limit the ground vibration to less than 1 ips.

Jan 1, 1978

By N. P. Kripakov

The Bureau of Mines has developed a unique new mine design procedure to determine the changing static load distributions imposed on under-ground support structures during the mining cycle. The procedure reduces the complexities associated with analyzing a three-dimensional problem. A combination of the multiple-seam displacement-discontinuity model and a two-dimensional finite-element window model produces refined results for a specific area of interest by assuming displacement compat-ibility between models. Input to the procedure includes the geometry of mined-out areas in up to two adjacent seams, the rock mass characteris-tics of the surrounding geology, the in situ stress conditions, and the mining sequence. The displacement-discontinuity program calculates ex-pected loadings for mine structures affected by the mining cycle and/or by overlying or underlying seams. Pseudoelastic finite-element analysis using a yield-factor approach determines the stability of coal pillars by simulating the degree and extent of nrogressive rib failure and sub-sequent load transfer. Application of the procedure is demonstrated on a field problem. In-duced stress changes predicted from the numerical model analysis are in reasonably good agreement with stress measurements obtained from an instrumented chain pillar affected by remnant workings in an upper seam.

Jan 1, 1988

By Daniel E. Sullivan

This Bureau of Mines publication examines the potential impact on minerals of the tariff and nontariff agreements that resulted from the Tokyo Round of the Multilateral Trade Negotiations, which were conducted under the auspices of the General Agreement on Tariffs and Trade. These agreements will affect minerals by reducing tariff levels and by changing rules by which they are traded internationally.

Jan 1, 1981