Search Documents

By B. J. Scheiner

The Federal Bureau of Mines investigated an electrolytic oxidation procedure for extracting lead, zinc, copper, and silver from lead-zinc concentrates. Concentrates slurried in brine were pumped through the anode compartment of electrolytic cells equipped with selective ion diaphragms. Hydrochloric and hypochlorous acids generated in the anode compartment converted the metal sulfides in the concentrates to soluble metal chlorides, sulfate ion, and elemental sulfur. Metal extractions of 92 to 100 pct were obtained from lead-zinc concentrates at an energy consumption ranging from 1.5 to 5.0 kW-hr/lb metal extracted. Sodium hydroxide was formed in the cathode compartment at a current efficiency of >99 pet. Silver and copper were extracted from refractory tetrahedrite minerals, but the process entailed a relatively high energy consumption. Sealing the top of the diaphragm cell utilized the chlorine more effectively, thereby reducing energy consumption 10 to 50 pct.

Jan 1, 1975

By Peter. PH. D. Cain

Smoky River Coal Ltd. mines low-volatile metallurgical coal by surface and underground methods in the foothills of the Rocky Mountains of Alberta, Canada. Current underground operations are confined to the 5B-4 Mine. Development of 5B-4 began in January 1998; production from depillaring sections commenced in July 1998. This paper describes the history of underground mining on the Smoky River property in terms of extraction methods and pillar design. The development of the present pillar design guidelines is discussed in this context. Recent work to prepare a number of case histories for back-analysis using the Analysis of Retreat Mining Pillar Stability (ARMPS) method is described, along with the modifications developed for calculating the ARMPS stability factor for retreat extraction of thick seams. The design criteria are described, as well as the geotechnical program implemented in order to verify its applicability.

Jan 5, 1999

Although the Stamler feeder/breaker has been used for coal crushing in underground mines for many years, it has only recently been applied to other crushing operations. Two companies presently using Stamler feeder/breakers for rock crushing were contacted regarding their experiences with the units in actual field use. In both cases information was obtained directly from the individuals responsible for field operation and maintenance of the units. White Pine Copper Co. has been using Stamler feeder/breakers for over two years to crush copper ore. They now have fourteen 450-ton-per-hour units on line. The ore has a compressive strength of from 18,000 to 28,000 psi and is extremely abrasive. Maintenance is performed on a tonnage basis. The breaker shaft is replaced every 250,000 tons (requiring about 4 hrs) and picks are replaced about every 1500 tons by the operator (requiring about 2 min per pick). Very little unscheduled maintenance has been required. Crushing costs are fairly high (estimated at 13 to 15t per ton including maintenance and operation) because of tale extreme abrasiveness of the material. A new Stamler feeder/breaker with Ultramet wear surfaces was put or line in June 1976. Ultramet was found to increase the life of belt transfer station surfaces by up to 400 percent and it is hoped that it will do the same for the feeder/breaker. At this time it is still too early to evaluate the performance of the Ultramet unit. If it does improve abrasion resistance, crushing costs could be greatly reduced. White Pine is very pleased with the units and the service provided by Stamler.

Jan 1, 1976

By W. E. Wallace, V. Robinson, M. F. Keane, V. Vallyathan

"An in vitro study of the biologic responses of surface-modified and native silica and kaolin was made to provide comparative information on the supression of cytotoxicity by pulmonary surfactant. The release of alveolar macrophage cytoplasmic enzyme, lactate dehydrogenase (IDH), and lysosomal enzymes B-N-acetylglocosaminidase (B-NAG) and B-ghucuronidase (B-GLUC) and sheep blood-cell hemolysis were moni¬tored as indicators of cell membrane damage and cytutoxicity. Surface modification of silica and kaolin with dipalmitoyl lecithin (UPI) resulted in complete abrogation of cytotoxicity of both minerals. These findings indicate that surface modification of minerals with different adsorption properties by pulmonary surfactant generally lessens their prompt adverse effects.INTRODUCTIONAcute and chronic silicosis are well-characterized clinical and pathologic entities resulting from the inhalation of crystalline silica (Morgan and Seaton, 1984). Kaolin, a layered aluminosilicate clay frequently mined and used in manufacturing, contains tetrahedral silica alternately layered with alumina octahedra. Kaolin is relatively .inert biologically, and distinctly greater pulmonary burdens are seen in patients with kaolinosis than are seen in patients with silicosis. Crystalline siliea (quartz) induces a significantly greater degree of fibrosis in exposed animals in vivo than does kaolin (Hamilton and Hardy, 1974; Parkes, 1982; Hunter, 1976; Sheers, 1964; Warraki and t-lerant, 1963; Lynch and Mciver, 1954; Lapenas et al., 1984).This difference in pulmonary disease associated with the two types of dust is not reflected by in vitro cytotoxicity as Jetermined by pulmonary macrophage bioassays or erythrocyte hemolysis. Cytotoxicity studies using crystalline silica and kaolin of similar size fractions show comparable bioassay response on a mass basis. These cellular bioassays, therefore, do not correlate with the relative in vivo pathogenicity of silicates."

Jun 1, 1988

By W. H. Engelmann

The electrokinetic (zeta) potentials of a charcoal granite in an aluminum chloride (AlCl3) solution and in an oleylanunonium acetate (C18H35NH3+ -OCOCH3) solution have been correlated with the specific damping values as measured by the pendulum sclerometer. This investigation shows that the pendulum specific damping attains a minimum at the isoelectric point for the charcoal granite-aluminum chloride and charcoal granite-oleylammonium acetate systems, and thus indicates that the penetration of the diamond points is a maximum at the isoelectric point.

Jan 1, 1967

By W. R. Reed

A computer model named the "Dynamic Component Program" (DCP) was specifically designed for predicting the dispersion off dust from haul trucks at surface mines. Validation of the DCP was completed by comparing its results with the results of the 1SC3 model and with actual dust measurements taken front two operating mine sires. Comparisons of the field measurements, predictions of the ISC3 model and the predictions of the DCP demonstrate that the results from the DCP represent, on average, an 85% improvement truer the ISC3 dust dispersion model results.

Jan 1, 2008

By J. T. Popp, C. M. McCulloch

This Bureau of Mines study reviews the geological factors that affect methane in the Beckley coalbed in southern West Virginia, including overburden, coalbed structure, type of and changes in lithology above and below the Beckley coalbed, and presence of fractures in the coal and rock adjacent to the Beckley. Depending on the depth, the Beckley coalbed emits from 216 to 520 ft3 of methane per ton of coal mined, and the Bureau estimates that methane emission in a deep, extensively developed mine in this area may exceed 3,000 ft3 per day per ton of coal mined. Average face cleat and butt cleat trends in the Beckley coalbed measured underground are N 33° W and N 53° E, respectively. Close cleat spacing con- tributes to the friable nature of the Beckley and provides easy movement for methane and water. Because rider coals, splits, and carbonaceous shales may contribute methane to mine emissions, predictions of methane emission based on gas content of the Beckley coalbed alone may be conservative. Beckley coalbed reserves in the study area are 234 million tons. The gas content of the Beckley coalbed averages 407 ft3/ton, and the coalbed gas reserves are 108 billion ft3.

Jan 1, 1976

By Neil B. Young

Carbonate minerals constitute a major fraction of the oil shale in Colorado's Green River Formation. Quantification of carbonate minerals is important for the characterization of oil shale, particularly because of their thermal activity in production of oil from shale. The carbonate minerals found in this oil shale are nahcolite (NaHCO3), dawsonite [NaA1(OH)2CO3], dolomite [(Mg1-xFx)Ca(CO3)2], calcite (CaCO3), and ferroan [(Mg1-xFex)CO3]. Although carbonate minerals can be removed by acid extraction from the balance of the oil shale, direct determination of carbonate minerals is complicated by the occurrence of the same cations in more than one mineral. A method for assigning the acid-soluble cations to the individual carbonate minerals was developed from two assumptions based on oil shale geochemistry: (1) Calcite and ferroan do not occur together, and (2) the ratio of iron and magnesium is the same in dolomite and ferroan. These assumptions were tested by the Bureau of Mines by applying the technique for assigning cations to 219 samples from the saline section of the formation. The reported carbonate mineral amounts were compared statistically with X-ray diffraction peak heights, verifying the cation assignment method.

Jan 1, 1975

By Charles L. Kimbell

Annual global steel industry investment is partly mirrored in the data for selected market economy countries that appear in table 13 for 1988-90. No reasonably comprehensive 1991 data were available for inclusion in this study, and the partial reporting available was so incomplete that it was impossible to demonstrate whether the level advanced or declined from the 1990 level of nearly $15.5 billion. Moreover, with the radical changes that are now being effected in the steel industries of the states that were the U.S.S.R. and its CMEA partners, it is most regrettable that comprehensive and comparable data, both current and historic, on investment in this area are not available. Updated information on market economy country petroleum industry capital and exploration expenditures by geographic area has been included in table 14, and it is evident that there was a substantial upturn in investment in 1991. The level of almost $74.5 billion was 14.5 % above the 1990 level and included gains in every topical category and geographic area. The source of information for this table has been changed to the Oil and Gas Journal Database from the previously used Chase-Manhattan Bank study of Capital Investments of the World Petroleum Industry, which has been discontinued. Because of this source change, it has been necessary to modify the structure of the table somewhat, but its total scope of coverage is regarded as basically unchanged. It should be noted that the grand total, as well as some of the detail appearing for 1987, corresponds precisely with those in the previous source.

Jan 1, 1993

By M. H. Stanczyk, I. L. Feld

Dewatering of typical Florida phosphate rock slime by electro - osmotic techniques was investigated to determine if a compacted , plastic solid product could be obtained with simultaneous recovery of the water for re - use . Tests with porous cathodes and rod - type anodes imbedded in dilute slime charges of up to 4 tons in weight showed that the slime could be dewatered to about 35 percent solids . The dewatered products had the consistency of modeling clay . In the large - scale tests using 2.5 - foot electrode spacings , about 21 kilowatthours of power were consumed per ton of water removed in thickening the slime from 17 to 25 percent solids , but the rate of water removal was so slow that the process was not considered commercially feasible . Other tests made with electrode spacings of from 2.5 to 8 feet showed that more rapid dewatering could be obtained but that the power required was excessive . However , for special uses such as stabilizing slime pond dikes where the cost of dewatering might not be a prime requisite , high voltages could be used to rapidly remove the water . Tests of 400 - pound slime charges using a combination of electroosmosis and vacuum filtration showed that the rate of dewatering could be expedited . The average power required to thicken a ton of slime from 15 to 35 percent solids was 5 and 50 kilowatt - hours when operating the electroosmotic filtration cell at potentials of 20 and 100 volts , respectively . calculated filtration area of about 10 square feet per ton of slime treated per day was required to thicken the slime from 15 to 35 percent solids .

Jan 1, 1964

By John H. Soule

The Royal John mine was examined in November 1942 by a mining engineer of the Bureau of Mines, who proposed development of the Royal John and other properties in the area. Geologists of the U. S. Geological Survey studied the area in 1943 and 1944 and made definite recommendations. Also, in 1943 the Peru Miring Co. mapped the Royal John and did considerable diamond drilling. The Bureau of Mines started the Royal John portion of a project pertaining to the general district in April 1944. This project was completed in Juno 1945. The work, consisting of diamond drilling, was supervised by Robert O. Hill, mining engineer, and the results were published in Report of investigations 3904, Exploration of Grey Eagle, Grandview and Royal John Claims, Grant County, N. WIC. In 1947 and 1948 the Royal John was re-examined by a Bureau engineer, and additional development to increase the reserves of low-grade lead-zinc ore was proposed. This project was started in August 1948 and completed in Juno 1949.

Jan 1, 1950

By Oliver C. Fursman

The Bureau of Mines undertook this investigation to study methods of utilizing red mud residues from production of alumina from bauxite. Pilot-plant tests were conducted using Jamaican and Surinam red muds. Both the carbon-lime-soda sinter process and electric-arc smelting with coke and limestone were employed to recover iron and alumina. Alumina recoveries of 85 to 90 percent were obtained by the sinter process; although iron recovery was about 80 percent, the magnetic product was finely divided and difficult to separate from the gangue. Smelting red muds in the electric-arc furnace produced a pig iron with 98-percent recovery of iron; up to 84 percent of the A1203 was recovered by leaching the calcium aluminate slag with Na2C03 solution. A titania product assaying 96 percent TiO2 was recovered from the nonmagnetic portion of Surinam red mud sinter by extraction with H2SO4. Leached calcium aluminate slags and brown mud (from the combination Bayer process) are possible raw materials in the manufacture of portland cement.

Jan 1, 1970

By Carl Belser

In 1925 the Park Utah Consolidated Mines Co., after several years of experimental work, installed a system for signalling from cages which has been operating efficiently and with low upkeep costs for the post 19 years. The system was adopted for a large western metal mine but was later abandoned be arse of the constantly shifting shaft alinement. Recently the system has been studied and probably will be put into service at two other large mines. One of the principal reasons wry the system has not boon adopted more widely has been the lack of adequate details both as to the desirability of having such a system and as to its construction and operation. Previous signaling, systems contained undesirable features, such as charged bare wires extending the full length of the shaft. Under the direction of O. N. Friendly, then general superintendent of the Judge Mining & Smelting Co., the present system, entailing the use of a samll current at low voltage, was gradually developed. Many of the refinements in the system wore contributed by Leonard Wilson, consulting electrical engineer, Salt Lake City, Utah.

Jan 1, 1945

By Giorgio Franceschetti

Explicit expressions are presented for the input admittance and effective height of several buried metal antennas, namely: (i) prolate spheroidal; (ii) spherical; (iii) oblate spheroidal; (iv) parallel plate; (v) parallel plate with protruding dielectric in the same plane of the plates; (vi) parallel plate with protruding dielectric in a plane normal to that of the plates (H-shaped antenna). Explicit expressions are presented for the input admittance and effective height of several buried metal antennas, namely: (i) prolate spheroidal; (ii) spherical; (iii) oblate spheroidal; (iv) parallel plate; (v) parallel plate with protruding dielectric in the same plane of the plates; (vi) parallel plate with protruding dielectric in a plane normal to that of the plates (H-shaped antenna). It is concluded that in all practical situations of "small" antennas approximation 1 is almost always appropriate. Computations were carried out for bare antennas, the extension to insulated ones being, however, straightforward. Although a rigorous theory of the antenna performance in a realistic semi-infinite conductive medium has not been developed, the results quoted should also be applicable when antennas are a few skin depths below the earth's surface. In particular, for the evaluation of radio-links under up-over -and-down operating conditions, the antennas can be replaced by dipoles of length equal to the effective height. Since the antenna's parameters are given in analytical form, it is also possible, by using Laplace transform techniques, to compute the transient response of the antenna. The transient is described by pole (short-time behavior) and branch-cut contributions (large time behavior). For these last terms, an asymptotic evaluation is possible, so obtaining closed form expressions for the response at large observation times, which is closely related to the dispersion characteristic of the environment.

Jan 1, 1973

I do not regard the criticism by Rankin of my work as valid or even meaningful. I strongly reject the assertion by Rankin that my results are invalid. As stated in my paper, the equation to solve (in e. m.u. ) is: [ ] where n2 =4 ps? . This may be rewritten as three scalar equations in Cartesian coordinates, one of which is [ ] The equation to be solved is the diffusion equation, and it is not appropriate to consider waves in this context. In the method a point-wise solution to the problem is approximated. As discussed in my paper the approach taken at discontinuities in conductivity is to choose the normal component of [E] at the discontinuity as the average of the normal components on either side of the discontinuity. This is similar to the well-known assumption made in obtaining Fourier series representations for piecewise continuous functions (Pipes, 1958; p. 51). In the geophysical problem this means that the discontinuity is approximated by a transition zone, which is a very good approximation for such cases. By using this approach, both the values of the function and its derivatives give a good estimate for those associated with the physical situation. It is not apparent and Rankin has not shown that "all the field components and the derivatives are grossly distorted in the region about the boundary" for geophysically realistic situations. He has given no evidence to support his assertation that the results are "invalid". Although Rankin declares that one cannot calculate the electric components from the magnetic, in his discussion he has not stated why this is so. After once calculating the magnetic components the electric components may be calculated, but one must insure that the initial solution is accurate enough to prevent significant round-off errors.

Jan 1, 1973

By Charles Sabine

The 27,960-acre Newberry Mountains Wilderness Study Area (WSA) is located in the Mojave Desert, 17 miles east-southeast of Barstow. In 1983, the U.S. Bureau of Mines, in conjunction with the U.S. Geological Survey, investigated mineral resources of the area as part of the wilderness review process. The Newberry Mountains are underlain by Paleozoic metamorphic rocks, Mesozoic plutonic rocks, and Tertiary volcanic rocks. Eleven mines and prospects were examined. Of the seven sites within the WSA, only the Northrup Prospect is mineralized. Only a few tons of manganese-bearing rock, containing 49% manganese oxide (MnO), are exposed, but exploration may disclose larger deposits. The Azucar Mine, a past producer of gold, is the only site examined outside the area that appears mineralized. Sample data from quartz veins exposed at the surface do not indicate that resources are present; however, the occurrence could not be fully evaluated because underground workings were not accessible. Sand, gravel, and stone are plentiful in the WSA, but alternate sources outside the WSA are available.

Jan 1, 1985

By Frank D. Lamb

Pyrophyllite, a hydrous aluminum silicate (Al2 Si4O10 (OH)2 ) has been mined in North Carolina and marketed without beneficiation for the past 100 years, but recent demands for higher-grade material indicate that an economical concentration method is needed for at least a part of the pyrophyllite production. Past production has depended upon selective mining and hand sorting, which is often unsatisfactory because of the finely disseminated character of the ores. The major impurity in North Carolina pyrophyllite ores is quartz, which accounts for the abrasiveness of the commercial product. Since pyrophyllite is only slightly heavier than quartz, those ores cannot be beneficiated by simple gravity-concentration methods. Some separation can be attained by differential grinding and air classification because of the difference in hardness of the two minerals) but the separation is not sharp. Froth flotation of pyrophyllite from Quartz has never been attempted commercially, but if the demand for high-grade material is sufficient, it would seem that this process offers the most premise of being economically feasible.

Jan 1, 1950

By N. A. Eilertsen

Among the numerous Low-grade manganese deposits in eastern Aroostook County, Maine, the Dudley deposit near Mapleton in the northern district is one of the few known to contain an appreciable tonnage averaging above 10 percent manganese. The ore body, consisting of stratified manganiferous hematitic shale, is over 5,000 feet long and ranges in width from 30 to 175 feet. The deposit was extensively explored during 1942-44 by the Manganese Ore Co., a subsidiary of M. A. Hanna Co. of Cleveland, Ohio. Data obtained from this work were made available to the State and Federal Geological Surveys for estimating ore reserves. An estimate by the Maine Geological Survey, using a 10-percent manganese cutoff and to a depth of 200 feet, shows 609,000 long tons of manganese metal in material averaging 12.6 percent manganese. By lowering the cutoff limit to 5 percent manganese, the estimate was increased to 919,000 long tons of metallic manga¬nese in material averaging, 10.4 percent manganese,

Jan 1, 1957

By James A. West

COUNTRIES of the Near East, with the world's largest and insist prolific petroleum resources, produced nearly 277 percent of the world's estimated total output of crude& oil in 1964 and accounted for about 60 percent of world exports of this commodity. Although petroleum largely dominated the mineral industry of tine area, production of antimony, chromium, copper, mercury, boron, potash, and phosphate rock was of world significance. Production of crude oil in Near East countries reached a record high of 7,520,000 barrels per day in 1964, an increase of nearly 11 percent over that of 1963. Kuwait maintained its position as the leading producer, accounting for almost 28 percent of the area's output. Saudi Arabia, Iran, and Iraq followed with 22.5, 22.2, and 16.5 percent of total area output, respectively. Despite record production, the Near East, proved crude oil reserve remained in excess of 211 billion barrels, or more than two-thirds of the estimated world proved crude oil reserve.

Jan 1, 1966

By J. B. Gayle

The rate of oxidation of coals with nitric acid has been used by earlier investigators4 5 6/ for determining fusain and for studying petrographic composition. These workers accumulated considerable evidence indicating that, for coals ranging from lignite to low-volatile in rank, the method gives values for fusain that agree satisfactorily with those obtained by optical methods. One group5/even concluded that, when discrepancies are noted between results obtained by chemical and microscopic methods, the results based on the oxidation reaction are probably the more reliable. Unfortunately, after concluding that the method was valid, most of these workers apparently lost interest. As a result, no attempt to exploit or apply the method to problems of utilization has been reported. Recent studies of the influence of inert petrographic constituents on the properties of cokes made from various coals7/ have indicated a need for additional means of characterizing coals and blends used for carbonization.

Jan 1, 1960