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By J. Ostwald, L. T. Matthews, C. E. Loo

Australia has large reserves of pisolitic limonite. Mining recently commenced on the Yandicoogina deposit to produce a high-grade sintering ore. The ore contains about 10 wt% combined water and simulated sintering temperature profiles indicate that progressive dehydration of ore particles occurs in the temperature range 300-700 degrees C. Studies by optical microscopy show that although the dehyrdrated ore particles contain numerous cracks, there is no change in the microstructure of the ore because topotactic transformation to haematite results in the formation of compact masses of very fine-grained haematite microcrysts. When the ore is held at around 1 200 degrees C for 1 min significant recrystallisation of these microcrysts occurs, resulting in the formation of optically visible, micrometre sized haematite crystallites. Studies to simulate the behaviour of ore particles during sintering (as nuclear particles surrounded by a standard adhering fines mixture) show that the recrystallisation process occurs much earlier at temperatures of about 900 degrees C. Further studies indicate that CaO in the adhering fines mixture enhances the recrystallisation of the ore nuclei. The results of the investigation indicate that the pseudo-relict haematite in sinters produced from ore blends that contain significant levels of pisolitic limonite consists of dehydrated goethite that has undergone significant recrystallisation and grain growth, a phenomenon that is facilitated by the presence of lime derived from the sintering melt.

Jan 12, 1992

By M. J. Spendlove

A progress report is presented on a research program in which an attempt was made to develop a practical sulfide-volatilization process for recovering tin from low-grade Bolivian ores. Shaft-furnace designs and operating techniques were studied in a series of experiments in which the objective was to sulfidize cassiterite to stannous sulfide, remove the stannous sulfide by volatilization, reconvert the stannous sulfide to stannous oxide, and collect the resulting fume. A shaft furnace was developed and operated in a final test in which many of the previous difficulties were surmounted. Since the supporting funds were exhausted at this point, the project was discontinued; recommendations for further improvements in furnace design and operation were made on the basis of interpretation of experimental results obtained in shaft-furnace experiments and other related studies.

Jan 1, 1955

By John Ward Smith

Detailed oil yield, lithologic, and mineral distribution data are presented for core and drill-cutting samples from the Western Oil Shale Corp. Project Utah EX-1 Corehole (WOSCO EX-I), drilled to sample a deeply buried oil-shale sequence in the Green River Formation of Utah's Uinta Basin. Drilling of this corehole was part of the evaluation of this site for possible oil-shale development by nuclear explosion. Sections sufficiently thick for nuclear development average 15 gallons per ton or less and consist predominantly of low-grade shales. Some properties of low-grade shales may be advantageous to a nuclear experiment by facilitating breakage, fracture development, and in situ retorting. The formation correlates precisely with the well-studied oil shales 25 miles east near the Colorado border. A 235-foot mineralized section containing nahcolite, shortite, and searlesite whose bottom lies 300 feet above the Mahogany zone is described.

Jan 1, 1972

By C. M. Lesher, R. R. Keays

"The komatnte-associated Fe-Ni-Cu sulphide mineralization at Kanihalda, Western Australia, is generally believed to be magmatic in origin, but a number of postmagmatic processes significantly modified the original distribution, structure, texture, mineralogy and chemistry of the ores. Two important types of mobilized magmatic sulphides are interpillow/interbreccia sulphides and hydrothermal vein-type sulphides. Interpillow and interbreccia sulphides occur interstitial to pillowed or volcaniclastic footwall metabasalts beneath or adjacent to the stratiform contact ore horizons. They are mineralogically and compositionally similar to massive ores (and are similarly depleted in PGE relative to the compositions of bulk samples of mined ores), but normally do not contain the distinctive chalco-phile ferrochromites characteristic of contact ores. They are interpreted as magmatic sulphides that have been mobilized from the overlying or adjacent massive sulphide layer during peak tectono-nietamorphism.Hydrothermal sulphide-quartz + albite veins also occur in the footwall metabasalt and contain unannealed deformation fabrics indicative of emplacement during retrograde metamorphism. The high Ni and Pd contents of these sulphides (7-13% Ni, up to 70 ppm Pd) indicate that the metals have been derived from the spatially associated komatiites and/or contact ores, consistent with the Pd depletion previously inferred for massive ores. Very low Ir contents and high Pd/Ir ratios of the vein-type sulphides confirm an aqueous transportation-deposition mechanism; hydrothermal transfer of PGE results in strong decoupling of Pd from Ir.There appears to be a complete continuum of sulphide mobilization at Kambalda ranging from whole-scale phy sical dislocation (fault offset ores) and selective mobilization (stringer sulphides) through nietamorphie replacement (interpillow/interbrec- cia sulphides) to jiydrothermal dissolution and redeposition (vein-type sulphides)."

Jan 1, 1984

By H. Shafick Hanna

The beneficiation characteristics of low grade Birmingham red iron ores of the Big Seam and Ferruginous Sandstone seams were investigated using flotation and magnetic separation after reduction roasting. Samples of Bib Seam Ore responded more readily to concentration than the Ferruginous Sandstone ores. The impurities inherent with the iron oxide minerals limit the grade of concentrates recoverable from these ores to a maximum of about 61% Fe if reasonable iron recoveries are sought. Flotation concentrates assaying 60-61% Fe and about 0.1% P with attendant iron recoveries of about 63% were achieved from Big Seam ore charges while those obtained from the low phosphorus Ferruginous Sandstone samples analyzed 54-56% Fe. Reductive roasting and magnetic separation of ground charges of the two ore samples yielded concentrates assaying 60-61% Fe. Iron recoveries were better than those achieved by flotation, but the magnetic products of Big Seam ore were high in phosphorus (0.2-0.3% P).

Jan 1, 1983

By Robert Hopler

Although electrical instruments were being widely introduced into the study of seismic tremors, attempts to understand and quantify shocks from blasting continued to use rather primitive methods well into the 19th century.

Jan 1, 2007

By S. H. Ash

THIS REPORT covers the third in a series of five projects into which the Conowingo tunnel system has been divided for geographical and practical reasons. It outlines the work constituting Project No.3 that consists principally of the following: (a) To sink the No. 15 shaft and extend the Alden, Sugar Notch, Baltimore No.2, and Laflin shafts from their present depths to tunnel level; (b) to drive a tunnel off these shafts to connect with the western end of the tunnel in Project No.1 (Lackawanna) and to a point 1 mile south of the No. 15 shaft; (c) to construct an emergency pumping plant at the No. 15 shaft, complete with 3 centrifugal pumps of 200-cubic-foot-per-second (c. f. s.) capacity each, and a discharge-water shaft and a discharge tunnel for conducting the water from the pumping plant into the Susquehanna River; and (d) to construct a lateral tunnel 1 mile long off the main tunnel in the vicinity of the No. 15 shaft, to be known as the Wyoming lateral. The project, as outlined, is a self-contained drainage unit that will permit unwatering inundated mines and safeguarding active mines in the Wyoming Basin of the Northern field and also will handle the water in the Lackawanna Basin, thus permitting the temporary pumping plant provided in Project No.1 to be discontinued. The pumps installed in the temporary pumping plant provided in Project No.1 can then be moved to the emergency pumping plants recommended in Projects Nos. 2 and 3, to be installed as the third or standby unit.

Jan 1, 1955

Electric power curtailments resulting from the coal strike, required Noranda Aluminum, Inc. to shut down its 140,000 ton-per-year (tpy) primary aluminum smelter at New Madrid, Mo., and layoff 308 workers. Other primary aluminum production facilities affected by the coal strike included the Aluminum Company of America plant at Evansville, Ind. which shut down half of one potline; the Eastalco Aluminum Co., smelter at Frederick, Md., which cut production by 7 percent; and the National-Southwire Aluminum Co. plant at Hawesville, Ky. which cut production by 6 percent. Alumax, Inc. announced that construction had started on a 91,000 tpy potline at the Eastalco primary aluminum smelter. The new potline will be owned 65 percent by Alumax and 35 percent by Mitsui & Co. Ltd. Howmet Aluminum Corp., which currently owns 50 percent of the existing 176,000 tpy facility, has the option of becoming a 50 percent owner of the third potline in 1982. Construction of the new line was scheduled to be completed in 1980.

Jan 1, 1978

By Oliver Bowles

Under a cooperative agreement between the Bureau of Mines, the United States Geological Survey, and the United States Bureau of Standards, a study of the stone-quarrying industries of the country was begun in 1914. The results of investigations made have been published from time to time.1 During the World War the Bureau of Mines centered its attention on problems relating to national defense, and detailed studies of stone-quarry problems were not undertaken except for an investigation of labor saving at limestone quarries, reported in Technical Paper 203, which related to a question of military importance. Since the return of peace, the high cost of materials and labor has made more imperative than in prewar times the conduct of investigations for aiding the quarrying industries in every way possible to adopt more economical methods and to utilize the most efficient labor-saving equipment. The publications already issued have had a wide demand, and in the interest of the quarry industries the bureau proposes to issue additions to the series as rapidly as funds are available. In an endeavor to promote economy and the reduction of waste in the slate industry, a study of slate quarrying was begun in 1920 and covered a period of about two years. Sixty-five active quarries were visited, and a detailed study made of all problems bearing on their successful operation. Field study was supplemented by a study of all information available in books or published articles on slate quarrying.

Jan 1, 1922

By J. R. White, S. W. Lambert, C. M. McCulloch

Examination of several coalbeds in Walker County, Ala., Cambria, Greene, and Fayette Counties, Pa., and Raleigh and Wyoming Counties, W. Va., indicates that cleat orientations are similar throughout a vertical sequence of strata. Studies of cleat orientation were carried out in underground mines that are operating in separate coalbeds vertically above one another. The data show that over a vertical separation of 100 to 400 feet, the average difference in coal cleat orientation between mines is 04° for the face and 08" for the butt cleat. Variations of coal cleat direction between coalbeds examined in strip-mined areas show similar values. Cleat orientations measured at outcrops agree well with the directions measured underground, suggesting that the amount of vertical separation between coalbeds has little effect on the resulting differences in cleat directions. The largest variation of cleat directions between adjacent coalbeds occurs where a large horizontal distance separates two sample locations. Cleat orientations for deeper coalbeds are most reliable where the data are taken from directly above.

Jan 1, 1976

El presente texto revisa algunos aspectos del programa de salud ocupacional en las compañías mineras aplicados en el ambiente de trabajo, la explotación de minas y el desarrollo de su control. Primeramente, se describe los riesgos encontrados en las condiciones de trabajo como la composición química del ambiente, la inhalación de polvo y gases en el aire del subsuelo. Como segundo punto, refiere las condiciones de seguridad de la mina, donde se sugiere que el personal de seguridad sea el más idóneo para la dirección del programa de seguridad. Para ello, es importante su capacitación en técnicas de evaluación y control, así como la participación de los médicos de la compañía. Por último, se mencionan algunas medidas de control en las minas, tales como el uso de equipos detectores de gases que determinen los contaminantes sólidos y gaseosos, la compra de un equipo detector de Cu, lámpara de seguridad y la instalación de un equipo de laboratorio químico adecuado,etc.

Jul 20, 1957

The Barmac autogenous crushing mill is one of the most successful new comminution technologies to become available to the mining and industrial minerals industries in this decade.The Barmac autogenous crushing mill is an innovative Vertical Shaft Impactor which operates in essence like a high intensity dry ore centrifugal pump with the reduction occurring primarily as a result of high velocity rock to rock impact in a fully rock lined crushing chamber. With applications in a wide range of mining and industrial minerals operations the Barmac autogenous crushing mill presents an opportunity to enhance reduction and liberation whilst providing many cost savings and production increases in new and existing plants.This paper briefly describes the operation of the Barmac autogenous crushing mill and reviews its benefits.

Jan 1, 1990

By Willard J. Tesch

The borehole surveying system described is used to measure ground movement over and near operating mines. The magnitude of any movement is con-trolled by the ground conditions, the mining method, and the mine progress. By correlating these factors with the measured movement, equations can be determined for predicting the effect of mine progress on the surrounding ground. These equations can also be used to predict the effect of mining a similar deposit with similar ground conditions. The borehole surveying system is used in cased boreholes to measure the inclination of the hole in two perpendicular planes. Grooved casing with an inside diameter of 3 inches is grouted in the hole. Two probes are used to obtain the data necessary to calculate the hole position versus depth. One of the probes contains a gyroscope, and the other contains a biaxial force-balance [s]ervoaccelerometer. Readings from the transducers in the probe are punched on paper tape by an automatic data acquisition system as the probe is pulled up the hole at 30 feet per minute by an electric winch. Readings from the inclinometer probe containing the accelerometer are used as input data to an on-line programmable calculator as they are punched on tape. The calculator computes preliminary results of the survey being made. The paper tapes obtained during the survey runs are later used as input to a computer that computes the offsets of the drill hole versus depth in true north-south and east-west planes. These offsets are printed for each foot of depth. Changes in these offsets between the first survey and subsequent surveys are a measure of the horizontal ground movement between the surveys.

Jan 1, 1976

By George A. Morrison

This paper describing the methods of mining and crushing limestone at the West Winfield, Pa., limestone mine of the West Penn Cement Co., is one of a series being prepared by the Bureau of Mines on mining practices, methods, and coats in the various nonmetallic mining districts. HISTORY The limestone deposits of western Pennsylvania have been exploited for many years and have been quarried extensively at West Winfield in Winfield. Township, which lies in the southeastern corner of Butler County.

Jan 1, 1931

By E. J. Rorem

Rockfall and unstable rock slopes can be con-trolled by using steel wire-rope net systems as barriers or as slope draping. The chief advantage of such systems over rigid type barriers is the flexibility of wire rope netting. This flexibility and strength permits kinetic energy dissipation with low maintenance requirements. Mining activities can produce temporary or long-term unnatural slopes and unstable rock faces that may produce rockfall hazards. Such conditions can necessitate efforts to minimize the hazard to workers, structures and equipment.

Jan 1, 1996

By George A. Bell

This paper reviewing the leaching practice of the New Cornelia mines of the Calumet & Arizona Mining Co. at Ajo, Ariz., is the first of a series being prepared by the Bureau of Mines on leaching methods and costs in the various mining districts. ACKNOWLEDGMENTS The author acknowledges the assistance of T. G. Chapman, consulting engineer, and E. D. Gardner, supervising engineer of the Southwest Experiment Station, Bureau of Mines, Tucson, Ariz.

Jan 1, 1930

By G. R. Fitterer

In the manufacture of steel by any process the refining period involves the partial elimination of the metalloids carbon, manganese, phosphorus, and silicon, by virtue of their reactions with ferrous oxide. At the end of this refining stage the metal consists chiefly of iron in which small amounts of these materials are dissolved. Unless some deoxidizer is added to the steel at this time, the reaction between carbon and ferrous oxide will continue with such force that it is impossible to form sound steel in the ingot molds. Instead, the product will exhibit a marked porosity due to the formation and trapping of carbon monoxide-the product of the reaction mentioned. However, if deoxidizers are added, steel may be obtained which is dense and free from gas bubbles. At the same time the deoxidation products will remain in the steel as impurities. For example, silicon additions form SiO2 or combinations of SiO2 and FeO. Additions of manganese form deoxidation products consisting of various proportions of MnO and FeO. It is also quite obvious that simultaneous additions of manganese and silicon will form oxide combinations either in the binary system MnO-SiO2 or in the ternary system FeO-MnO-SiO2. Work at the Pittsburgh Experiment Station of the United States Bureau of Mines, in cooperation with the Carnegie Institute of Technology and the Metallurgical Advisory Board, involved the study of such deoxidizing reactions and their products. In this connection considerable information is necessary concerning FeO, MnO, SiO2, and Al2O3, and their various combinations. Some of the most needed data are the melting points of all of these materials. At the outset of this work ordinary methods of melting point determinations were found to be inadequate for various reasons, and the procedure finally selected involved the use of the micropyrometer with occasional corroboration by quenching methods. The reasons for this selection, together with a description of the apparatus, are given in the following pages.

Jan 1, 1932

By T. J. Ballard

The Ore Knob mine, in Ashe County, N.C., was one of the largest producers of copper in the eastern states during the 1870's. The ore occurs in a fissure vein, which strikes N. 64° E. and dips nearly vertical. The country rock is granite gneiss. Drilling indicated that the vein structure is approximately 200 feet wide and 1,500 feet long. The vein material shows evidence of replacement of the original gneiss by sulfides. Solution cavities in the vein were noted in some places. The ore minerals and pyrrhotite, chalcopyrite, pyrite, and minor quantities of sphalerite. The gangue contains biotite, magnetite, albite, calcite, and many silicate minerals.

Jan 1, 1948

By Forster G, Datta P. K

Many high temperature industrial processes involve gaseous halogen-bearing environments. Essentially, these fall into three subject areas: power generation, waste incineration and especially extractive metallurgy. Fundamental to any understanding of the process chemistry and efficiency in the process technology is an adequate knowledge of background thermodynamics relating to metal-chlorine reactions. In this context, existing free energy/temperature diagrams for metal chlorides do not include many elements, in particular the so called refractory elements from Group V and Group VI of the Periodic Table, namely niobium, tantalum and vanadium, and molybdenum. This paper reports estimation and calculations of the free energy values for these chlorides. The data is discussed in the context of high temperature chlorination processes.

Jan 1, 1991

By D. D. Campbell

The Hat Creek coal deposit s occur within folded and faulted Tertiary (Eocene) strata of the Coldwater Group, which comprises weakly lithified shales, siltstones and conglomerates underlying the floor and lower flanks of the valley of Upper Hat Cr eek . This upland valley,16 miles in length and 2-4 miles in width, is located within the eastern foothills of the Coast Mountains, 120 miles northeast of Vancouver, approximately midway between the towns of Lillooet and Ashcroft, in the Interior Dry Belt of British Columbia . Most of the valley floor is covered by till and glacial outwash deposits ranging up to 500 feet in depth. Became of this overburden cover , the majority of the data on the coal deposit have been obtained from diamond drilling done during 1974?76 by the property owner, B .C. Hydro and Power Authority. Because of the limitations imposed by the lack of out crop, the Tertiary geology at Upper Hat Creek is imperfectly known; however, it appears from correlation with other coal-bearing Tertiary remnants in the southern interior of the province that these remnants, including Upper Hat Creek, may represent preserved segments of the western shoreline of a Tertiary continental sea along which deltaic swamps developed and were sustained for unusually long stable periods, giving rise to the world's thickest known coal beds.

Jan 1, 1977