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By V. B. Dale

This paper is one of a Federal Bureau of Mines series covering the mineral resources of the Nation. It briefly describes most of the tungsten deposits in Cochise, Pima, and Santa Cruz Counties, Ariz. Most of the descriptions are from field examinations by the two senior writers, prior to July 1957. Wolframite first was identified in Arizona in 1896 by W. P. Blake, Territorial Geologist. Tungsten mining began about 1900 in the Little Dragoon deposits of Cochise County, and about 1901 in Las Guijas district of Pima County. The price history of tungsten is an erratic one; consequently, production has been erratic. Prices rise during wars and periods of national preparedness. Production of tungsten ore was stimulated greatly by a Government purchasing program, announced on May 10, 1951, wherein the Government agreed to purchase standard-grade tungsten concentrates at $63 per short ton unit5/ for 5 years or until 1,468,750 units were purchased. This was later increased to 3,000,000 units, and after this amount had been purchased in June 1956, the purchase of an additional 1,500,000 units was authorized. Government purchase, however, was suspended in December 1956 before completion of this latter program, and the price of tungsten concentrates declined sharply. The price had dropped to $15 per short ton unit, duty extra,6/ by the last part of July 1957.

Jan 1, 1960

By Raymond B. Ladoo

"The increasing realization of the fire hazards involved in the use of wooden shingles caused the National Lumber Manufacturers' Association to beginsome five years ago a search for a suitable fire-resistant paint. The problem was submitted to the Educational Bureau of the Paint Manufacturers' Association of the United States and work was started by Mr. Henry L. Gardner at the Institute of Industrial Research, Washington D.C. in collaboration with Dr. Herman von Schrenk, a timber expert of St. Louis.The results of this,work have been described by Heckel, in ""Asbestos"", (Heckel G.B., Asbestos in the Paint Industry, Asbestos, Vol. 2, July, 1920,pp.- 5-10).,,who gives the following formula for one of the colors as typical: It will be noted from this formula that ""asbestine"" forms 33% of the total liquid pigment by weight or 31.8% of the solid constituents. Hockel in the article referred to describes this paint,as ""asbestiform"" and assumes since ""asbestine"" is magnesium silicate it must be the chrysetile variety of ""Asbestine"", however, is not asbestos but is a trade name for a fibrous variety of talc mined in the Gouverneur district, St. Lawrence County, New York. This rather natural error persists through the article and credits asbestos with many desirable properties which are characteristics of talc."

Aug 1, 1920

By V. A. Marple, K. L. Rubow

"4.1 IntroductionIn previous chapters impactors have been described as useful instruments for classifying particles by their aerodynamic diameters and for measuring particle size distributions. These impactors can be used most reliably if the user has some understanding as to how the impactor classifies particles and what parameters are important in this classification process. This understanding can best be obtained by a theoretical inspection of inertial principles.This chapter reviews the most recent theoretical impactor work and the latest theoretical efficiency curves. Procedures are then given for using these efficiency curves in the design and evaluation of cascade impactors. Finally, several examples are given comparing theoretical and experimental efficiency curves, pointing out when the theory can be used with great confidence and when the theory should be used only as a guideline.Due to the rather simple principle of operation of an inertial impactor (i.e., the impingement of a jet of particle-laden air on a flat plate) the impactor readily lends itself to theoretical analysis. Three notable works in the early 1950,s were those of Davies and Aylward (1951), Davies et al. (1951), and Ranz and Wong (1952).Davies and Aylward (1951) used a method of conformal mapping to obtain an analytical solution to Euler's equation for the flow of a frictionless fluid through a rectangular impactor. Numerical calculations were then carried out whereby the equations of motion of the particles were solved in a stepwise manner, leading to a determination of the efficiency curves. Since this theory assumed potential flow, the effect of Reynolds numbers on the characteristics of the impactor could not be determined.Ranz and Wong (1952) used an approximate flow field to calculate the efficiency of both round and rectangular nozzle impactors. In the vicinity of the stagnation point, the flow field was assumed to be that of frictionless stagnation flow. Here, the resulting equation of motion for the particles was found to be in a form similar to equations for free vibration with viscous damping. Therefore, the known solutions of the vibration equations were applied directly to the problem and the efficiency curves calculated. This solution technique, however, could not take into account the various geometric variations such as the jet-to-plate distance in the determination of the efficiency curves.The work of Ranz and Wong (1952) was later modified by Mercer and Chow (1968) and Mercer and Stafford (1969) so that the rather simple flow fields of Ranz and Wong (1952) could be used to account for various jet-to-plate distances. The same techniques, however, were used to determine the impactor collection efficiency curves."

Jan 1, 1986

By Jeffrey H. Welsh

This report presents a study on the use of computerized, continuous remote monitoring systems for fire and explosive atmosphere safety in underground coal mines. The effects of these systems on the safety level in mines are investigated, and the relationship between mine safety regulations and computerized, continuous, remote monitoring is analyzed.

Jan 1, 1982

By T. A. Kubala

Electric discharge ignition has been reinvestigated in a modified Hartmann apparatus for lycopodium powder with air. Minimum stored energy to ignite air dispersions of lycopodium was 25 to 30 mj; ignition occurred with 1 gram of lycopodium dispersed into the 2.7-liter vessel. Ignition energy was measured as a function of the weight of powder used, although some reservations are expressed concerning the uniformity of the lycopodium-air mixtures. In particular, wall layers of lycopodium, remaining after dispersal of 1 gram of lycopodium, were as easily ignitable as the most easily ignited air dispersion. Thus, an unanswered question has arisen concerning the role of surface coatings in the flammability of all marginally ignitable mixtures.

Jan 1, 1981

By B. J. Dalton

The Bureau of Mines Helium Research Center has developed a computer program for solving two-phase equilibria data for binary mixtures and for evaluating thermodynamic functions of interest, including all critical points. This computer program was used to calculate equilibrium points on the PVTu surface for the helium-nitrogen system as predicted by the Van der Waals equation of state. Numerical values are tabulated and illustrations are presented for 1,279 equilibrium points and for quantities needed to construct Ponchon diagrams. Equilibrium ratios as a function of pressure at constant temperature and of temperature at constant pressure-are also shown graphically. In addition, saturated partial molal volume and partial molal enthalpy data are given. It is shown that the Van der Waals helium-nitrogen system exhibits retro-grade condensation of the second type for liquid helium concentrations of about 0.07 mole fraction or less and pressures below about 45 atm. It is also shown that the critical point is at a -maximum value of pressure (at constant temperature) and of temperature (at constant pressure).

Jan 1, 1971

By Oliver Bowles

"Conservation of slateWaste slate is a problem of outstanding importance in the slate industry, for a very large proportion of all slate quarried is thrown on the waste heap. While many uses for waste slate have been found, the demand calls for merely a fraction of the present supply of unused material. If the slate industry is to increase in prosperity, the producer's energy must be directed toward the development of ways and means of reducing waste to the lowest possible point. The Bureau of Mines of the Department of the Interior has devoted much study to this problem and a recent bulletin ** contains a detailed discussion of the waste problem.Attention has recently been directed toward an improved method of cutting slate in quarries, a method that promises to reduce greatly the percentage of waste material. The method has been introduced since that bulletin was published, and this supplementary paper covers the details of the process.A reversion in method,In connection with this new mode of operation history is repeating itself in a very interesting way, for the old quarry bar used years ago with steam drills, and later discarded in favor of the channeling machine .and the hammer drill, has been salvaged from the scrap heap, and again put to active use. The occasion for its employment is an attempt to improve quarry methods by the substitution of drilling for channeling or blasting."

Oct 1, 1923

By Jennifer S. Riefenberg

The U.S. Bureau of Mines conducts basic and applied research related to predicting, eliminating, and/or controlling rock bursts in underground hard-rock mines and coal bumps in underground coal mines. An important element in this research is the development of a reliable and efficient microseismic source location technique. This report presents the results of a Bureau study to develop and evaluate a new algorithm to locate microseismic events based on the Simplex method, a powerful linear programming technique. The technique was tested on both field data and simulated data. Microseismic event source locations obtained with this new Simplex-based algorithm were shown to have less error than those locations obtained using a least squares method. It was concluded that the Simplex approach to source location of microseismic events can be used effectively in microseismic monitoring.

Jan 1, 1989

By J. G. Donaldson

Cobalt-tungsten binary deposits were formed in laboratory experiments by hydrogen reduction of the anhydrous mixed vapors of cobaltous chloride and tungsten hexachloride. The materials were sublimed in seperately heated zones of reaction tube and were transported in a stream of purified helium into the deposition section of the tube where the chloride gases were reduced to metal by a countercurrent flow of hydrogen. Heattreating of the near stoichiometric binary metallic deposits converted nearly all to the intermetallic compound Co3W, however, small quantities of both cobalt and tungsten remained. Mechanical tests showed that the tensile strength of heat-treated 75 percent cobalt-25 percent tungsten deposits was twice as high as that of similarly treated deposits of cobalt.

Jan 1, 1965

This publication summarizes, for potential contractors and other interested parties, the proposed research, development, and demonstration contract projects programed by the Bureau of Mines for fiscal year 1977 (October 1, 1976-September 30, 1977) under its Advancing Coal Mining Technology program. The objective of these projects is to provide an ordered and sequenced series of advances toward the overall goal of providing the system technology required to increase the productivity of the coal mining process.

Jan 1, 1977

By C. A. Robotham

The following; paper describes underground mining practices of the Riverside Cement Co. of Los Angeles, Calif., in the Stanley limestone deposit at Crestmore, Riverside County, Calif. It is one of a series of papers being prepared for and published by the United States Bureau of Mines on mining methods and costs in tae various mining districts in the United States. ACKNOWLEDGMENTS Acknowledgment is made of the assistance received from E. D. Gardner, supervising engineer of the United States Bureau of Mines Experiment Station, Tucson, Ariz., in connection with the preparation of this paper and of the cooperation of John Treanor, president of the Riverside Cement Co. Valuable assistance in developing the mining methods was obtained from a study of similar practices in the copper-mining; districts of Ray and Globe-Miami, Ariz.

Jan 1, 1934

By J. F. Shaw

MINE fires are usually extinguished by constructing seals in the approaches to the areas to exclude air from the fire areas, which smothers the fires in an oxygen-depleted atmosphere. Seals should be substantially constructed and made as nearly airtight as possible and should be provided with a sampling pipe so that samples of the atmospheres behind the seals may be collected at regular intervals. Methods of constructing seals and of sampling and analysing mine atmospheres are fully described in Bureau of Mines publications. (1, 2). Information obtained on the composition of atmospheres behind fire seals is helpful in determining if a fire has been extinguished or if there is any danger of an explosion when a fire area is being sealed or unsealed. The progress of a mine fire can best be determined by studying percentages of carbon dioxide, carbon monoxide, and hydrogen in the atmosphere behind the seals. Hydrogen will be formed in a bituminous- or subbituminous-coal mine when the temperature exceeds 480° F. and in an anthracite mine when the temperature exceeds 660° F. (3). Carbon monoxide and carbon dioxide are both products of combustion of coal, wood, or other organic compounds. The presence of carbon monoxide has long been accepted as an indication of a mine fire. A sealed fire area should not be reopened until the carbon monoxide has disappeared. Trends in the percentage of carbon dioxide are also useful in determining the status of a mine fire. Carbon dioxide is sometimes liberated by rock strata. In this case, carbon dioxide in the atmosphere behind a seal will be from two sources-the rock strata and the fire. When the, fire is extinguished, carbon dioxide will be liberated from only I source, the rock strata, and when the percentages of carbon dioxide are plotted, the slope of the curve will not be as steep as when this gas was being liberated from 2 sources. If the only source is the fire, the percentages of carbon dioxide will gradually decrease after the fire has been extinguished. By studying analyses of a mine-fire atmosphere, it is possible to determine if the atmosphere is explosive; if the mixture is capable of becoming explosive when mixed with air; and if the mixture can be made nonexplosive or be prevented from becoming explosive by being mixed with an inert gas. These factors can be computed mathematically or determined graphically. The mathematical calculations advanced by Ash and Felegy (7) are discussed, and graphical solutions of their equations are presented. It is believed that the graphical solution will be extremely helpful in determining the characteristics of a mine-fire atmosphere when fighting a fire, because the results can be obtained in a matter of minutes, and there is less likelihood of an error being made under the stress incident to control efforts. The experimental and theoretical work upon which the formulas are based have been adequately described and are not discussed at this time (5) (6).

Jan 1, 1955

By Kung-Lee Wang

This Bureau of Mines study illustrates the economic significance of the Florida phosphate industry to the State and to the Nation. Environmental considerations related to phosphate industry activity are discussed briefly. Based on forecasts of Florida phosphate production in 1975, and using 1972 dollars, regional and national output value, income, and employment created by the phosphate industry were estimated for 1975. State and Federal government tax revenues generated by the phosphate industry, are also measured. Further, the concentrated impact of the phosphate industry on certain Florida areas and on regional industries is examined. Finally, the phosphate industry's importance to the U.S. balance of payments, U.S. agricultural production, and the Frasch sulfur industry is considered, in addition to byproduct fluorine, and potential byproduct uranium from fertilizer manufacturing.

Jan 1, 1974

By Raymond B. Ladoo

Toward the end of 1920 , the average grades of ground feldspar offered to the pottery industry were so poor and so generally unsatisfactory that many of the largest consumers decided to take active steps for their own protection . A few of the potters made arrangements to grind their own feldspar , while others asked the Bureau of Mines to make a detailed study of the problem and to suggest methods of improvement . Accordingly such a study was undertaken, the partial results of which are outlined in this preliminary report . The outstanding features of the present feldspar industry which are of interest in this connection are stated below. (1 ) Many grinding companies do not own or control all or even a major part of their sources of crude material , but buy in job lots from many sources . (2 ) There is great need of more adequate engineering and chemical control over mines and mills . ( 3) ~ Out of date , inefficient methods and equipment for mining and grinding are in common use . (4) Little or no cooperation exists between feldspar producers , but on the contrary many feldspar companies are exceedingly secretive . This tends towards (a) preservation of obsolete methods ; ( b ) want of knowledge of the essential features of production , market requirements , and the relation between total milling and consuming capacities of the country; ( c ) inefficient and often mistaken trade practices ; ( d) unprofitable and even ruinous competition in dull periods . (5) The small size of many feldspar deposits precludes maintenance of an efficient organization at each individual mine . ( 6 ) Many of the best deposits of feldspar situated close to railroads are becoming depleted , which results in gradual lowering of grades , and increase in cost for better grades . (7) There is a lack of exact mowledge of the ceramic properties and behaviour of feldspar by some consumers , which results in ( a) purchase of feldspar on the basis of price alone , thus encouraging low production costs at the expense of quality , and ( b) inefficient and expensive cross- hauling of both crude and ground feldspar .

Jan 1, 1922

By J. Tomlinson

Shuttle car trailing cable splices were tested for resistance to failure upon being subjected to repeated bending, abrasion, and tensile shocks using a new testing method that closely simulates shuttle car induced stress. The results show that under normal stresses, splices can be made to withstand the equivalent of three months of operational use. Restoring the tensile strength to the conductors is found to be as critical as restoring flexibility. Splices in which the conductors are of slightly unequal length did not present as serious a workmanship problem as previously thought since test results show that the conductors tend to equalize when longer cables, in contrast to short cables employed in previous testing methods, were used. Dynamic recordings of cable tensile stresses are presented for a shuttle car and the new simulated testing method. Two simple but effective methods for removing insulation using a knife and a pair of pliers are described. None of the designs tested for a sacrificial splice covering were satisfactory.

Jan 1, 1979

By Charles S. Allbright

To develop a method for predicting the stability of a fuel during long-term storage from rapid aging tests at 200° F, the Bureau of Mines determined the stabilities of three gasoline base stocks and an alkylate blending stock in both sealed storage and aerated storage at 110° F for periods extending to 32 weeks. Stabilities of samples containing gasoline-additive compounds were compared by aging, using two methods--rapid aging in a bomb at 200° F for intervals up to 16 hours and storage at 110° F. The additives used were an uninhibited tetraethyllead motor mix, N,N'-di-sec-buty1-p-phenylenediamine and 2,6-di-tert-butyl-4-methylpheno1. Results were related by graphs that enable predictions of gum and sediment formation during storage from data obtained in bomb tests. A premium-gasoline base stock and the alkylate proved to be stable, but the two regular-grade gasoline base stocks were found to be unstable. Addition of the diamine antioxidant improved the stability of both of the regular gasoline base stocks, while the phenol antioxidant improved only one of them. The presence of the tetraethyllead decreased the storage stability of all four fuels, both with respect to formation of gum and precipitation of inorganic sediment. The rapid test at 200° F appears to offer promise as a basis for a method of predicting gasoline stability in long-term 110° F storage.

Jan 1, 1968

By A. K. Schellinger

1. In the United States, the industrial application of centrifugal force for separating phase constituents has been confined almost entirely to aqueous systems at room temperature. This paper presents results for experimental tests on the use of centrifugal force for separating the liquid and solid phases in molten nonferrous alloys. 2. The development and use of a small centrifuge for treating molten metals is described. The centrifugal apparatus was, in essence, a 3-inch diameter spinner pot, which revolved, within -a gas -fired furnace, at speeds up to 3,000 r.p.m.

Jan 1, 1953

By S. E. Khalafalla

In support of its goal to maintain an adequate supply of minerals to meet national economic and strategic needs, the Bureau of Mines has investigated a novel hydrometallurgical system with sulfur dioxide. Differential leaching with dissolved SO2 of manganese, nickel, and cobalt from their hydrous oxides was found to be very rapid and efficient--almost instantaneous and quantitative. In this method a given weight of mixed oxides previously ground to minus 200-mesh is slurried with a leach solution containing a specified quantity of dissolved SO2 for 10 minutes at room temperature and ambient pressure. An empirical leaching parameter, R, is defined as the ratio of the number of SO2 moles in the leaching solution to the weight of the metal oxide charge. Plots of the variation of metal extraction with the ratio R generate a series of sigmoidal-shaped curves, each of which is characteristic of a specific metal extraction. A threshold value of R is required to initiate the leaching of a given metal from the mixed oxides. Once this threshold is reached, the metal recovery can increase to more than 95 pct in very short times. For increasing values of R, the extractability of various metals by SO2 follows the order: Mn > Ni > Co >> Fe, Al, Cu. Differences in the threshold R values permit a variety of metal separations to be made simply by adjusting the quantity of SO2 in the contacting solution. Success in this leaching system depends upon comminuting the sea nodules to less than 0.149 mm (100-mesh). Above this critical size, leaching is slowed due to the inaccessibility of inner particle reacting groups to the SO2 leaching agent. This results in nonselective extraction and less extraction of preferred metal values. At or below 0.149 mm, leaching by SO, is possible with all its attributes of selectivity, sensitivity, and rapidity. Leaching with HC1 solutions of the same pH level as dissolved SO2 yielded mixed, slow, and incomplete metal extractions. This observation rules out any interpretation based on hydrogen ion as the leaching agent. The leaching curves resemble the complexometric titration curves of heavy metals with specific coordination species.

Jan 1, 1981

By E. W. COCHRANE, R. HOPKINS, G

The number of completed petroleum refineries in the United States continued to decline in 1938, but the total capacity to process crude oil increased materially. This information was obtained in connection with the Bureau's annual canvass of refinery capacity as of January 1, 1939. In spite of the addition of a half dozen plants in Illinois and the inclusion in this year's list of several more "pot-stills" in Montana, the total number of plants, and inactive, declined from 551 on January 1, 1938, to 538 on January 1, 1939. was entirely in shut-down plants, as the number of operating plants rose from both active The decline 431 to 435. Yost of the plants dismantled were situated in Wyoming and Texas, parts or several from the latter being transported to Illinois. About 10 more East Texas refineries were dismantled in 1938, leaving about 15 plants in the field, only 8 of which were operating on January 1, 1939. Although the total completed capacity increased from 4,351,151 barrels on January l, 1938, to 4,508,555 barrels on January l, 1939, the operating capacity declined, and the inactive capacity increased about 50 percent, or from 380,955 to 574,770 barrels. These shifts in capacities reflect the comparative slump in the refining industry in 1938 after the prosperous year 1937. Daily average crude runs in 1938 were 3,192,000 barrels, from which it may be figured that the operating ratio for the active units was about 81 percent of crude and for all completed equipment 74 percent. The highest daily throughput in 1938 was about 3,400,000 barrels, at which time the reserve capacity represented in the active equipment was at least 500,000 barrels, in addition to about that much capacity shutdown. In an emergency, much more reliance could be placed on the reserve capacity of the active equipment, as much of the shut-down capacity is obsolete at present specifications and prices. Regarding obsolescence, the refiners reported 418,165 barrels of their idle capacity in good condition on January l, 1939 and 156,605 barrels in poor condition. However, it is probable that the former reflects an optimistic viewpoint. Refinery activity, as represented by new construction and dismantling, declined materially in 1938. The new capacity added in 1938 was 378,350 barrels compared with 394,680 barrels in 1937. Probably 1939 will see a much larger decline, as the new capacity under construction on January 1, 1939, totaled only 142,250 barrels compared with 283,020 barrels the preceding year. The capacity represented by the new plants was negligible throughout

Oct 1, 1939

By Louis H. Berkelhamer

"INTRODUCTION The method of differential thermal analysis suggested by Le Chatelier (1)1 in 1887 has recently emerged as an outstanding means of studying the constitution of various substances, particularly clays, soils, and miscellaneous hydrous materials (2). The literature ably discusses the applications and results obtained but has paid too little attention to specific details of construction of the apparatus. Knowledge of the apparatus is of importance to the experienced research man as is extremely useful to the novice v ho ventures into this field of analysis. Further, it is generally acknowledged that the variations in design and conditions of operation are one of the essential causes for differences in characteristic temperatures as reported by various investigators. A step forward in the elimination of such differences is the publication of the details of construction and operation of a simple and inexpensive apparatus that has proved useful at the southern Experiment station of the Bureau of Mines, where it was used in cooperation with the University of Alabama, Tuscaloosa, Ala."

Jul 1, 1944