Search Documents

By J. E. Schiller

The Bureau of Mines is investigating methods to treat waste water that contains cyanide. This report describes a new method that removes heavy metals and all forms of cyanide. In the first step, hydrogen peroxide and sodium thiosulfate are added at pH 7 to 9 in a 1:2 molar ratio to convert free and weakly complexed cyanide to nontoxic thiocyanate. Then steryldimethylbenzylammonium chloride is added to precipitate ferro-cyanide, and finally, ferric sulfate is added as a sweep floc and sequestrant for heavy metals. After the suspended solids settle, the water is polished by filtering. The water initially contained 1 to 5 mg/L Fe, 1 to 5 mg/L Cu, and 10 to 30 mg/L total cyanide; the level of each of these constituents was reduced to less than 0.02 mg/L.

Jan 1, 1983

By W. A. Calhoun

A method for concentration of the nickel-cobalt-bearing mineral, siegenite, from a table middling has been developed by the Bureau of Mines at Rolla, Mo. The table middling is composed of a complex series of sulfide minerals, occurring in mill operations in the southeast Missouri "lead belt." In these operations the siegenite is lost as a separate concentrate, being diverted to other products. The procedure also includes recovering commercial-grade concentrates of copper and lead. A low-grade zinc concentrate, a potential coproduct, was also made.

Jan 1, 1962

By R. L. Grant

The conventional gallery test used by the Bureau of Mines Explosives Testing Station and corresponding establishments in other countries to establish the permissibility of explosives serves principally to differentiate the relatively safe explosive from the positively unsafe one. It has been recognized for many years that a more definitive test is needed to measure the relative incendivity to firedamp of explosives and explosive devices. A new method - the oxygen-value test - for measuring this incendivlty quantitatively has been devised and is being tested at Bruceton, Pa. To date, this testing bas been limited mainly to straight nitroglycerin dynamites. It is planned to study application of the method to permissible explosives in the near future. These results will be reported later. In the present report, permissible explosives will not be considered specifically.

Jan 1, 1954

By Will H. Coghill

The jig men of the Tri-State (Joplin-Miami) zinc district complain about the flakiness of their mill feed. They believe that the flakiness of the composite grains of gangue and mineral are to blame for losses of zinc; that is, that the flaky grains in the jig tailings have higher zinc tenor than the cubical grains. Although the evidence which follows contradicts this belief, no effort is made to give a final and conclusive answer. On the other hand, there is outlined a positive and mechanical method which the operator may use to pursue this and similar investigations. DISCUSSION OF SCREENING METHOD Hand-sorting is obviously not satisfactory for separating cubical grains from flaky grains because the personal influence can not be removed. Screens, however, may be used with success. A set of each of two types of screens is required; namely, the square-hole type and the rectangular (rectang, oblong) type. The square-hole screens must be of the double Tyler scale; that is, the order of the sieves should be after the fourth root of two instead of the customary square root of two; close sizing is important. The size of the rectang screens may be selected by trials so that a part of the material already closely sized on the square-hole screens, will pass the oblong holes. Obviously, the cubical grains will remain on the rectang and the flaky grains will pass through. Hence the mode of operation is to screen first on square-hole screens and then split the products on the oblong-hole screens.

Jan 1, 1928

By Aldo L. Furno

Sufficient quantities of combustible vapors are released by some sulfurs to produce flammable atmospheres under prolonged storage. Hydrogen sulfide and carbon disulfide appear to be the principal flammable constituents in the vapor space above molten sulfur. If sufficient carbon disulfide is present, ignition of the vapor-air mixtures can occur spontaneously on contact with the heated surfaces found within storage tanks.

Jan 1, 1963

By J. E. Zeilinger

This Bureau of Mines report describes the preparation characteristics of the significant coalbeds of Clarion County, Pa. Of the 15 samples collected, 1 was of metallurgical quality as received, 4 could be sufficiently upgraded to provide acceptable products, and the remaining 10 samples could not be upgraded to metallurgical quality because their sulfur contents could not be lowered to meet the standard. For steam or power generation, 1 sample was of low sulfur content as received, 1 sample could be upgraded to low sulfur content, and 10 samples could be upgraded to medium sulfur content. The original sulfur content of the remaining three samples can be appreciably reduced by removal of the sink 1.58 specific gravity material; however, these coals would be classified as medium sulfur coals both before and after removal of the sink material.

Jan 1, 1968

By Sidney Katell

This study presents the economics of the hot-carbonate purification process for removing C02. It considers three variations of the process in order to meet the design specifications, which call for a feed-gas flow of 10 million standard cubic feet per hour (std.c.f.h.) with C02 inlet concentrations of 10, 20, and 30 percent and exit C02 values of 5, 2, 1, 0.5, and 0.1 percent. Inlet pressure and temperature are 350 pounds per square inch [e] (p.s.i.g.) and 300° F., respectively. Estimated capital and operating costs are shown in the following to tabulations: [ ]

Jan 1, 1960

By Paul M. Tyler

The value of mica depends chiefly upon the size of the flat sheets into which it can be split and also upon whether it is clear or stained. Muscovite (white mica) and philogopite (amber mica) are the micas of commerce. Biotite (black mica) and other varieties are virtually unsalable. Vermiculite, an altered mica having the extraordinary property of expanding greatly when heated, preferably should not be classed commercially as mica. Mica is marketed as (1) cut or uncut block, (2) sheet, (3) splittings, and (4) wet or dry ground mica. In the United States, mica that will not yield flat films over about 1-1/2 inches square, or that is ruled, rumpled, or flawed in any way, can be sold only as scrap, its sole use being for making ground mica. Only sizes that will yield rectangles 1-1/2 by 2 inches or larger can be classed as sheet quality; slightly smaller sizes may be classed as punch, and under certain circumstances still smaller sizes, down to about 1 inch square, may be used for splittings, which are mostly a thousandth of an inch thick or even thinner. Splittings, however, are produced in large quantities only in British India, where labor costs very little. Even there the work is done mostly by children, who not only work cheaper but have a delicacy of touch that enables them to do the splitting faster and better. No mechanical process yet devised will permit ordinary splittings to be made economically in the United States.

Jan 1, 1938

By W. W. Adams

"During the calendar year 1925 the Bureau of Mines received from the operators of several hundred mines and quarries complete accident records covering deaths, permanent disabilities, and “lost time” temporary injuries. Some of the companies, - those that participated in the National Safety Competition-also furnished information showing the number of man-hours of work performed during the year. With these two types of information it was possible to calculate the accident-frequency and accident-severity rates of the different plants. Complete and comparable reports of accidents and Man-hours of “exposure” were received from 34 underground metal mines, 59 underground coal mines, 15 underground mines producing other nonmetallic minerals, and 102 open quarries or open-pit mines. The figures in the table appended to this report show the accident severity rates and other data for each of the 34 underground metal mines and for the group as a whole. It is proposed to publish similar figures for the other classes of mines and quarries at an early date.The 34 metal mines listed in the table are situated in Arizona, Idaho, Kansas, Michigan, Minnesota, Missouri, New Jersey, New Mexico, Oklahoma, South Dakota., and Utah; they employed 5, 925 men, an average of 174 men per mine, including employees above-ground as well as underground. With but few exceptions, 50 men was the minimum number of employees in any mine. The total period of employment or “exposure” at the 34 mines was 14,612,607 man-hours, an average of 2,466 hours per man, or the equivalent of 308 work-days of eight hours for each employee. Accidents resulted in 15 fatalities, 9 permanent disabilities, and 1,950 temporary “lost time” injuries (causing disability exceeding remainder of shift). The fatal and nonfatal injuries represented 132,575 days of disability. Thus the accident frequency rate for the group was 135 accidents per million hours and the accident severity rate was 9.073 days lost per thousand hours of 1 “exposure”. The severity rates ranged from 0.227 to 88.653, while the ·range of the accident-frequency rates was from 16. 6 to 307 .4. In compiling the accident severity rates shown in the table, all accidents caused by explosives were weighted at twice the number of days actually lost, as one of the purposes of the National Safety Competition was to stress the prevention of accidents caused by explosives."

Sep 1, 1926

By P. H. Floyd

Laboratory test work has shown that the Germania ferberite-scheelite ore can be concentrated to an acceptable grade. A ferberite concentrate assaying 66.9 percent tungstic oxide was made, with a recovery of 75.4 percent. A second concentrate of ferberite and scheelite was made assaying 54.2 percent tungstic oxide. Final beneficiation of combined rougher gravity concentrates was accomplished by roasting, magnetic separation, sulfide flotation, and retabling, to give a final ferberite-scheelite concentrate of 66.2 percent tungstic oxide, with a 91.1-percent recovery. INTRODUCTION This presentation covers the results of laboratory beneficiation tests conducted on tungsten ore from the Germania Consolidated Mines, Inc., by the Bureau of Mines Mineral Dressing Section, Northwest Electrodevelopment Laboratory, Albany, Oreg. This mining property is near Fruitland, on the southern edge of the Spokane Indian Reservation, Stevens County, Wash. The Germania district produced tungsten concentrates before and after World War I; interest is being renewed in the district because of the metal shortage.

Jan 1, 1954

By S. A. N. Sheya

Many gold-bearing ores in the Western United States also contain small amounts of mercury. The presence of mercury creates potential pollution and health hazards during several steps in gold processing. An investigation was undertaken by the Bureau of Mines to develop techniques for removing mercury from cyanide mill solutions by selective electrowinning to reduce the potential hazards. Sixty-five percent of the mercury was selectively electrowon from synthetic carbon strip solution at applied potentials of 1.00 to 1.50 V when using a mercury-coated platinum or copper plate cathode. Increasing the active surface area by using mercury-coated copper wool resulted in up to % pct of the mercury being electrowon from mill carbon strip solutions that contained 1.9 to 20 ppm Hg, 20 to 345 ppm Au, and 0.35 to 39.5 ppm Ag. About 98 pct of the silver was electrowon with the mercury onto the mercury cathode. Gold extraction ranged between 0 and 20 pet. Results of the investigation showed that choice of cathode material was critical to the success of the process. Selectivity was not achieved using uncoated steel wool cathodes.

Jan 1, 1988

By L. A. Neumeier

The Bureau of Mines evaluated the properties of a Zn-0.75 pct Cu-0.12 pct Ti alloy extruded at temperatures between 400° and 720° F. The extrusions were made with a reduction ratio of 28-to-l and at relatively slow speed. Rod was also extruded at 560° and 640° F with a reduction of 255-to-l. With increased extrusion, temperature, extrusion pressures decreased substantially and creep resistance of the rod improved significantly. Coefficients of thermal expansion were low in the long rod dimension. Microstructures, hardness, and tensile properties were also evaluated, and a limited evaluation was made of bend ductility at 32° F for the rod extruded with the 255-to-1 reduction.

Jan 1, 1969

By Frank E. Cash, Max S. Petersen

"INTRODUCTION Explosives have been used in ever—increasing amounts since gunpowder was invented. For hundreds of years only low explosives of the deflagrating type were used, and they were fired by means of a flame or hot object. Ben¬jamin Franklin first ignited gunpowder from a distance in 1751 by means of an electrostatic spark. Further efforts to develop a satisfactory electrical method to ignite explosives from greater distances were overshadowed by the invention of safety fuse in 1831, as this offered a relatively simple and inexpensive means of firing explosives.The discovery and introduction of high explosives of the detonating type and the invention of the fulmitate of mercury blasting cap about the middle of the nineteenth century provided the needed impetus for inventors to develop means of firing the cap by electricity. The original high-tension igniter, following Benjamin Franklin's experiment in which the detonating compound was ignited by a spark, was discarded in favor of a low-tension igniter, in which the detonating compound was ignited by a heated wire. The past 2 decades have seen considerable improvement in the design and construction of electric detonators to make them safer and more efficient, yet in spite of the improvement it is estimated that less than 50 percent of the explosives used in industry today are ignited or detonated electrically. The trend, however, is toward the use of electric methods. In recent years numerous-mining companies have introduced electric blasting exclusively at their mines as a means of improving safety and efficiency."

Sep 1, 1946

By D. A. Lucero, J. E. Brockmann, L. A. Mondy, K. L. Rubow, D. J. Rader

"Department of Mechanical Engineering, University of Minnesota, Minneapolis, MNExperimental and correlated stage responses (the fraction of particles entering an impactor that are collected on a stage) are presented for the Andersen Mark III and Marple personal cascade impactors. The impactors were operated upright and fully assembled so that interstage interference and wall losses could be properly studied. The observed stage responses showed maxima that fell significantly short of unity, meaning that a monodisperse aerosol is never collected exclusuvely on one stage, but is distributed among several stages and internal losses. Correlations for the stage responses are presented so that the experimental results can be used to determine size distributions with available data-inversion algorithms. Simulations with log-normal distributions show significant differences between dpa50 histograms and the more accurate distributions that result by taking the response functions into account.Cascade impactors are widely used for the measurement of aerosol size distributions; their ruggedness and simplicity of operation make them an attractive choice for a variety of environments. In one common application, the aerosol of interest is drawn through the impactor, and the amount deposited on each stage is determined gravimetrically. The primary objective is to extract as much information as possible about the initial size distribution from the resulting set of weights. Unfortunately, the reconstruction of contin-uous size distributions from finite data sets is an ill-posed problem. Not surprisingly, a variety of such reconstruction techniques are presently in use; the success of each method depends on the particular nature of the aerosol sample and the instrument response.Inversion of impactor data by any of these techniques requires that the response functions for each stage be known. The stage response function gives the fraction of particles entering the impactor that deposits on that stage. Values of the response function range from zero to one, and depend on impactor operating conditions (e.g., geometry, flow rate, and gas properties) and particle properties (e.g., diameter, density, and shape factor). As interstage interferences and particle losses will affect each stage's response, experimental determination of stage responses should be made for fully assembled impactors. Unfortunately, impactor stage response functions are rarely reported; rather, single-stage efficiency curves are given that provide an incomplete description of impactor performance.This paper presents experimental stage responses for two fully assembled cascade impactors: the Andersen Mark III and Marple personal impactors (model 298, Andersen Samplers, Inc., Atlanta, Ga.). These calibrations were performed with monodisperse liquid droplets for both impactors and also with monodisperse solid spheres for the Marple personal impactor. The calibration results for the Mark 111 impactor presented here have been previously reported in the response-function format (Rader et al., 1989). The calibration results for the Marple personal impactor, however, were originally presented in the single-stage efficiency for¬mat (Rubow et al., 1987) and have been reanalyzed in this work. Losses within both impactors are considered, and their treat¬ment within data inversion techniques is dis¬cussed. In addition, correlations for each impactor's response functions are presented so that these calibration results can be easily included in data-inversion algorithms. Size distribution inversions using these response correlations are compared with the standard cut-point method for two lognormal test dis¬tributions."

Mar 1, 1992

By Welby G. Courtney

The Bureau of Mines conducted a field test program in the Pittsburgh coal seam to investigate the effect of water sprays in the suppression of respirable dust being formed while cutting with a continuous-mining machine. Emphasis was given to the location of spray nozzles on the top and bottom of the cutting boom. Results showed that (1) sumping caused about 60 percent of the dust escaping the face area, and shearing and loading caused the other 40 percent; (2) during sumping, top and bottom sprays were equally effective in dust suppression and reduced dust ~13 percent; (3) during shearing and loading, bottom sprays reduced dust 61 percent and were about 50 percent more effective than top sprays; (4) the combination of top and bottom sprays was slightly more effective than the separate systems, but water consumption increased 60 percent; and (5) inclusion of throat sprays decreased dust reduction by removing some of the water from top and bottom sprays where it was more effective.

Jan 1, 1978

By A. L. Service

The four periods of test operation described in Report of Investigations 5219 indicated that planer mining of phosphate rock was feasible. Corrective measures proposed for design deficiencies indicated in test 4 had to be evaluated, however; and, before the attempt to design a prototype production model, it was considered advisable to test the original machine under more severe operating conditions. Planer A was modified, therefore, during the latter half of 1955, and one additional period of experimental operation was conducted in the Anderson mine of the Montana Phosphate Products Company near Garrison, Mont., during the first 4 months of 1956. Test 5 was made in a stope, where the phosphate bed had been offset in a number of places by minor faults. Considerable difficulty was found in negotiating the irregularities caused by these faults, and productionwise the test was not as successful as some of the previous ones. Information obtained, however, was valuable in designing model B.

Jan 1, 1959

By Kihong Park

A hygroscopicity tandem differential mobility analyzer (HTDMA) technique is used to determine size-effect of nanoparticles (NaCl, (NH4)2 SO4, KCl, NH4NO3, MgCl2,CaCl2) on their hygro­scopic properties (deliquescence relative humidity (DRH) and hygroscopic growth factor (GF)). The HTDMA system uses a combination of two nano DMAs and two regular DMAs to measure particle size change in a wide dynamic particle size range. Particles are subsequently analyzed with a transmission electron microscopy to investigate the potential effect of particle structure or morphology on the hygroscopic properties. We found that structural properties of NaCl and (NH4)2SO4 particles also play an important role in determination of the DRH and GF and are more pronounced at smaller diameters. Data show that the DRH of NaCl nanoparticles increased from *75% up to *83% RH at 8 nm and that their GF decreased with decreasing size. The extent to which the GF of NaCl nanoparticles decreased with decreasing size was greater than theoretically predicted with the Kelvin correction. The GF of furnace-generated NaCl nano­particles that have pores and aggregate shape was found to be smaller than that of atomizer-generated particles that are close to perfectly cubic. For the case of atomizer-generated (NH4)2SO4 nanoparticles, we observed no signi?cant size-effect on their DRH, and the measured GF agreed well with predicted values using the Kelvin correction. For furnace-generated (NH4)2SO4 nanoparticles, a gradual growth at moder­ate RH without noticeable deliquescence behavior occurred. Their TEM images showed that contrary to atomizer-generated (NH4)2SO4 nanoparticles the fur­nace-generated (NH4)2SO4 nanoparticles are not perfectly spherical and are often aggregates having pores and holes, which may favor holding residual water even in the dried condition. For atomizer-generated KCl, MgCl2, and CaCl2 nanoparticles, we observed no signi?cant size-effects on their DRH and GF for the mobility size as small as 20 nm.

Jan 1, 2008

By William O. Vanderburg

This paper describing the practice at the Wolf Pongee concentrator at Federland, Colo., is one of a series on similar subjects being published by the United States Bureau of Mines. The author acknowledges the assistance of Loach, manager of the Wolf Tongue Mining Co., and of W. G. Roseborough, superintendent of the golf Tongue mill, in the preparation of this paper.

Jan 1, 1933

By Raymond B. Ladoo

SOAPSTONE

Feb 1, 1922

By Peter J. Clarke

Development of the mineral and energy resources of Afghanistan appeared to be a top priority of the Soviet-controlled Government in the country. In the Afghan Government's plan for 1980-81, the largest allocation in the development budget was for mines, industry, and energy (46.7%). In contrast, only 23.1% of the budget was allocated for agricultural development, despite the fact that the great majority of the population was dependent on farming. The mineral industry of Afghanistan consisted of the production of natural gas, cement, coal, fertilizer materials, and rock salt. Production levels for all of these commodities were down an average of 45% from those of 1978, before the Soviet invasion. Prior to the invasion, small quantities of asbestos, barite, and talc had been produced along with about 6,000 to 7,000 kilograms per year of lapis lazuli, a semiprecious gem stone. Afghanistan had supplied about 80% of the world's output of lapis lazuli. Following direct Soviet intervention, production of these minerals declined to near zero.

Jan 1, 1983