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By Oliver Bowles

Since 1922 when the Bureau of Mines issued a report2 covering the slate industry in detail, changes in technology have taken place which have an important bearing on the industry. The present paper comprises a record of these changes. Though the value of slate, for roofing, structural, blackboard, sanitary, and electrical uses is generally recognized, it has many competitors. To meet this constantly increasing competition producers are promoting economies in manufacture, and improving processes, thereby lessening costs of production, and are placing on the market products of the highest possible quality, thus creating satisfaction and confidence on the part of the user. This endeavor to place the industry on a better basis, both as regards processes and products, is shown in the recent developments in technology which are presented herein. Valuable assistance in obtaining data for this paper was given by W. S. Hays, secretary of the National Slate Association, N. M. Male, president of the National Slate Association, and Robert Notvest, consulting engineer, Cleveland, O.

Jan 1, 1926

By S. Borle

The microstructural features produced in friction stir welded AZ31, AZ80 and AZ91 alloys are examined when different welding parameters are applied. The microstructures primarily consist of a-Mg grains with a-Mg + Mg17A112 colonies, however melted films of Mg17A112 are produced in AZ91 alloy when high rotation speeds are applied. When the rotation speeds are slow, or the travel speeds are fast the Mg17A112 were incorporated into the stir zone, however they do not exhibit an elongated lamellar morphology associated with melted films. In the case of AZ80, the extruded base material contains a smaller fraction of Mg17A112 and few of these phases are observed in the stir zones. The results are explained based on the dissolution rate and melting temperatures of Mg17A112 controlling the overall morophology and fraction of phases in the stir zone.

Jan 1, 2011

By G. S. Hanumanth

Sedimentation of particles during the liquid metal processing of particulate metal-matrix composites can affect the homogeneity, and thereby the properties, of the cast product. A novel electrical probe has been developed to measure the in-situ volume fraction of ceramic particles in molten metal baths. Using this probe, sedimentation rates for 90 pm silicon carbide particles dispersed in molten aluminum A356 alloy were measured over a wide range of particle volume fraction, 0.05 to 0.3. The sedimentation rate was found to depend strongly on particle volume fraction; the time to clarify a 0.15 m depth increased from approximately 60 to 500 seconds as the volume fraction increased from 0.05 to 0.3. Measured sedimentation rates agree well with the predictions of a sedimentation model based on one-dimensional, two-phase flow theory in which the inter-phase drag function is derived from the momentum equation, utilizing the Richardson-Zaki Equation for sedimentation in aqueous systems. The implications for solidification are discussed.

Jan 1, 1993

By H. W. Leavenworth

Research was conducted by the Bureau of Mines to develop a technique to grow metallic fibers from a sulfide mineral. In this research, chalcopyrite (CuFeS2) was made sulfur deficient, and the remaining sulfur partitioned to the iron in the mineral to liberate metallic copper, or to the copper to liberate metallic iron. The metals formed on the surface as fibers and in the interior as spherical particles. Fiber growth is very fast. Lengths of 3 to 4 cm form in a matter of minutes, and the diameter of individual fibers is less than 1 µm. The mechanism of fiber growth is explained, and the reactions are reversible as predicted. Copper fibers can be made to grow from the surface at 400° C or to dissolve back onto the solid surface and be replaced by iron fibers at 625° C. Growth and dissolution can also be controlled to form copper/iron duplex fibers.

Jan 1, 1974

By G S. B Karunatillake

Following a pre-feasibility study, Mount Isa Mines commenced a feasibility study on the deposit of the George Fisher Mine in May 1997. Board approval was granted in May 1998 to construct a 2.5 million tonne per annum mine and to upgrade existing concentrator and smelter facilities. The world-class George Fisher zinc-lead-silver deposit is located approximately 22 kilometres north of the city of Mount Isa, in north-west Queensland and is 2.6 kilometres north of the existing Hilton Mine. It will be a large-scale underground mine, sustaining a profitable zinc-lead-silver business in Mount Isa for at least ten years. This paper will outline the details of the mine that was developed during the feasibility and design phase. It will include a description of the mining methods, ventilation, fill, ore handling, services and infrastructure. The utilisation of existing assets and the development of innovative ideas were essential to the successful economic development of the George Fisher Mine.

Jan 1, 2000

By E. C. Perkins, R. S. Lang, D. M. Taylor, H. Dolezal

The amenability of titaniferous slags and domestic mineral concentrates to chlorination was determined in a 6 - inch diameter fluidized bed chlorinator . Ilmenites from Valley County , Idaho ; Aiken , S.C ,; Trail Ridge , Fla .; and MacIntyre , N.Y .; and a titaniferous magnetite from Iron Mountain , Wyo . , were used in preparing the slags . The domestic minerals tested were an ilmenite concentrate from Valley County , Idaho , and a rutile concentrate from Magnet Cove , Ark . A high - grade Australian rutile was used as a standard for comparison . The impurity content of the slags and minerals tested , which was the most critical factor affecting their performance , was dependent on the geographical source of the material . All of the materials tested were amenable to chlorination in a fluidized bed although some required special operating conditions . Titanium extractions and chlorine utilization were over 90 percent for most of the slags and the Australian rutile . The Valley County , Idaho , ilmenite performed well in the reactor despite its 34 percent iron content .

Jan 1, 1963

By Osarnu Inoue

In Mitsubishi Continuous Copper Smelting and Converting Process, smelting, slag-matte separation and matte converting are continuously carried out in series in three furnaces connected by launders. As a result of this operational configuration of the furnaces, influence of the change in operating condition in upper stream, such as variation of feeds in the smelting furnace, propagates to down stream with some delay. In order to achieve stabler operation, process control algorithm based on the dynamic characteristics of each furnace would be very effective. In this study, the dynamic process simulation model was developed for the smelting furnace. The model consists of two mathematical modules, i.e. the thermodynamic module and the mixing module. The calculation results using operating data obtained at Naoshima Smelter showed good agreement with the actually observed change in temperature, composition and flow rate of matte and slag at the outlet of the furnace. In addition, operation parameters such as reaction efficiency of oxygen and coal, dead volume of melts were estimated.

Jan 1, 1999

By Patrick R. Taylor

Keywords: Thermal Plasma, Electroreduction, Electrolysis, Transition metals, Waste treatment, Molten oxides, Chromium oxide. An innovative process to treat transition metal oxide waste materials from diverse sources is presented. This technology involves using reverse-polarity DC plasma driven electrolysis in molten oxides. The process results in the recovery of the transition metal and other heavy metals from waste. By-products generated throughout the processing was converted to environmentally acceptable slag. The significance of this technology is that the treatment of the waste is accomplished in one step which in turn lowers the cost of remediation. Moreover, this process uses high temperature properties of thermal plasmas, which makes it possible to use molten oxides instead of halides as electrolytes. Chromium was successfully reduced from chromium oxide through the plasma driven electro-reduction process. It was shown that the selection of the appropriate ionic conducting oxides was critical for the formation of a slag that would enhance the reduction of chromium oxide.

Jan 1, 2004

By Paul M. Tyler

MILITARY power stems from industrial power and industrial power in turn depends predominantly upon an ample and assured supply of mineral raw materials. It thus becomes the duty of mineral economists to collate the vast array of data and logical deductions in order to reach an unemotional judgment as to the ability of the Soviet economy to withstand the strain of prolonged military action on the modern scale. Russian publications, reports: and official speeches have been laboriously screened and analyzed. Since these are the sources of information for the lower echelons of the Soviet industrial organization itself, they carry factual data that can be pieced together to show the present-day pattern. Apparent contradictions and obvious distortions or omissions can often be rationalized on the basis of observations made by foreign engineers and consultants during the 1930'5 and by checking against the technical literature published before even so-called technical articles were riddled by bombastic and presumptuous claims.

Jan 6, 1951

By D. R. Mitchell

MEETING for the thirteenth time in New York as part of the five-ring circus known as the Annual Meeting A.I.M.E., the Coal Division experienced a wartime boom in attendance. Technical sessions were crowded and whereas 65 seats were set up for the annual luncheon meeting of the Division over 100 members showed up, many of whom had to be fed elsewhere. Possibly the Coal Division should adopt "13" as its lucky number. Discussions at technical sessions, formal and informal, were lively. Those papers containing material directly concerned with the war, or containing information that might be usable for war industries, were enthusiastically received. Some criticism was made in regard to the present method of handling discussions and it was suggested that better success would be had in getting discussions in the record by the use of hired reporters. This is being considered by the executive committee of the Coal Division.

Jan 1, 1943

By T. R. Jolley

This publication describes the control of fires in inactive coal deposits in the Western United States, including Alaska by the Bureau of Mines. Material presented should contribute to a better understanding of the purpose, process, and benefits of the program. Forty fires were extinguished or controlled in the Western United States and Alaska from 1948 to 1958 under a national program directed by the Bureau's Health and Safety activity. Thirty-five fires were controlled by smothering; three were controlled by the isolation method; and two were extinguished by removing the burning coal, smothering it with incombustible material, and backfilling the fire zone. The fire-control projects were distributed as follows: Alaska 2, Arizona 1, Colorado 9, Montana 9, New Mexico 4, Utah 2, and Wyoming 13. The total cost of the 40 fires extinguished or controlled was $1,203,957. Of this cost, 12.8 percent was engineering and administrative and 87.2 percent was contractual services.

Jan 1, 1959

By Olav K1omstad1ien

The lean, but extensive iron ore deposits of the Dunderland Valley north of Mo i Rana, Norway, is the raw material for the Rana Mines which is a division of the state owned steel mill A/S Norsk Jernverk. Activities for the exploitation of the orebodies were commenced in 1902 by the English Dunderland Iron Ore Company. During its operating period the company constructed a total of two large scale concentrating plants. The activities were strongly marked by technical problems and labor disputes. Thus actual production was limited to the years 1904-1908, 1928-1931 and 1937-1939. During these periods a total of 1.9 million tons of crude ore was mined and 0.6 million tons of concentrates produced for export. The present plant commenced operations in late fall of 1964. Up to and including 1976 about 26.6 million tons of crude have been put through the concentrating plant and about 10.7 million tons of concentrate produced.

Jan 1, 1978

Smelter operating and environmental requirements demand high on-stream time (high reliability) from the primary smelter sulfur retention device - the sulfuric acid plant. The key to reliable smelter sulfuric acid plant operation is the gas cooling and cleaning system. Problems in the gas cleaning system cause corrosion, plugging, equipment failure, etc - plant down time, in the contact section of the plant. The last fifteen years have seen major changes in gas cleaning system design to the current standard of brick lined venturi scrubber, packed gas cooling tower with plate type liquor coolers and lead or plastic tube precipitators. The current-design offers improved impurity scrubbing along with increased reliability. In addition, a number of alternate gas cleaning systems have been offered. Chematics LAB System: Monsanto DuPont Dynawave System; Lurgi venturi scrubber with lead star gas cooler. This paper will review the design and operating advantages, disadvantages, and risk of the standard gas cleaning system and compare it to the alternate systems.

Jan 1, 1992

By J. W. Paul

Withdrawing timber in coal mines is done for the purpose of inducing the roof to cave in the mined-out areas and thereby relieve stresses in the immediate roof material over the working places adjacent to the breakline of the roof, thus preventing the crushing of the ends of pillars and adding to the safety of those engaged in pillar extraction. A secondary purpose is the recovery of timber for further use either as prop-, crossbars, lagging, sprags or cap pieces. At some mines timber is withdrawn as a precaution against fire which may he of spontaneous origin, because wood always aids a fire of any origin. With some of the power-driven types of machines now in use a greater proportion of mine timber may be recovered, and in mines where pillars are left too narrow for their removal some of the timber in rooms might be salvaged for further use.

Jan 1, 1933

By William K. Tolley

The U.S. Bureau of Mines (USBM) is investigating hydrometallurgical processing techniques to recycle metals from semiconductors and other advanced materials. Cadmium and tellurium were recovered from mixed CdTe/CdS scrap produced in the manufacture of thin-film photovoltaic devices. Selective cadmium dissolution was achieved using oxygen-pressure leaching in dilute sulfuric acid. Leaching the scrap for 90 min at 110° C in 2.2NH2S04 under 400 psig 02 yielded 97% Cd extraction; however, cadmium content of the residue ranged between 4% and 7%. Soluble iron was added to the lixiviant to catalyze oxidation of the CdS component. Tellurium and sulfur remained in the leach residue primarily in the elemental form. The iron and tellurium were removed from the cadmium-rich leach liquor by adjusting the pH to 5.3. The cadmium was recovered as cadmium sulfate crystals by evaporating the solution. Alternative leaching and purification schemes are discussed.

Jan 1, 2010

By M. Lange

The postulation that primary platinum group metal (PGM) matte will chemically react with magnesia-chrome bricks when temperatures exceed 1500°C was tested. Magnesia-chrome brick samples were heated in contact with matte at 1300°C to 1750°C for 30 minutes, after which the refractory samples were analysed using reflected light microscopy and scanning electron microscopy. The samples were all completely penetrated by matte. As the temperature increased the matte also penetrated the fused aggregate grains and disintegrated them. The chromium concentration of the matte inside the refractory samples was found to be slightly higher than that of the bulk matte. At temperatures of 1500°C and higher, MgO, FeO, and magnesium-rich silicate crystals could be identified in the matte directly adjacent to the refractorymatte interface. Phase relations clearly indicated that chemical reactions take place between primary PGM matte and the magnesiachrome refractory material at temperatures above 1500°C, but that these reactions are more complex than expected from FactSAGE® calculations.

Jan 1, 2014

By Clarence Karr

AN EXTENSIVE characterization was conducted on the neutral oil components in a low-temperature bituminous coal tar. A total of tai individual compounds identified with respect to individual isomers, and at least 55 other compounds were indicated to be present. The amounts were determined in all instances. A comparison of isomeric distribution in the tar with thermo-dynamic equilibrium distribution, and kinetic distributions indicated that the composition of the tar largely reflected the structure of the coal from which it was formed. Detailed descriptions are presented for the separatory and qualitative and quantitative procedures for the characterization of the neutral oil component. These include micro fractional vacuum distillation, displacement liquid chromatography, gas-liquid chromatography, countercurrent distribution, and infrared and ultraviolet spectrophotometry. Descriptions are given for the synthesis of authentic specimens of alkylindenes, The ultraviolet and infrared spectra of 134 polycyclic compounds, ranging from alkylindenes to alkylphenanthrenes, either found in the distillable neutral oil, or thought likely to be present, are also given.

Jan 1, 1967

By Elliot Gillerman

The title of this paper implies the presence of silver, nickel, and cobalt minerals at, the Alhambra mine. Perhaps this should be amplified to include uranium, as pitchblende also occurs, possibly in mineable quantifies. A brief history of the Alhambra mine is of interest, both from a historical angle and as pointing up the importance of geology in the-present development. The Alhambra is one of several mines in the Bullards Peak or Black Hawk dis¬trict, ass it is more familiarly known, in southwestern. New Mexico, which was mined for silver in the 1880?s and 18901s, Silver valued between $500,000 and $1,000,000 was extracted from the mine in the 10 years prior to 1893, when operations ceased. Almost all the silver mined was native silver, although a small quantity of argentite was produced. Nickel and cobalt were recognized in the ores, but they were thought to be of no consequence.

Jan 1, 1959

By C. M. K. Boldt

The Bureau of Mines surveyed waste disposal sites at 18 metal and non-metal mines and conducted laboratory and full-scale field tests to de-termine the effects of tailings deposition techniques on physical properties of tailings pond beaches. Survey data included measurements of beach slopes, descriptions of deposition techniques, and measurements of beach physical properties taken at various distances from the point of discharge. Laboratory tests involved depositing two types of tailings, each with different grain-size distributions, into a settling trough and determining the resultant physical properties of settled materials along the length of the beach. Side confinement and the closeness of the water pool to the point of deposition caused the laboratory results to be inconclusive. Full-scale field deposition tests conducted at the tailings pond of a cooperating mine showed that there were similarities in relationships between exit velocities of tailings slurry and physical properties of the settled tailings on the beach.

Jan 1, 1988

By Harry E. Tufft

Data were obtained by the writer from a number of the large coul-mine operators in Illinois, on the consumption and cost of timber used in their mines and the quality of the timber now being used as compared with former years. This information supplemented by comparative date for previous years published in bulletins of the filinois Coal Mining Investigation series, and other sources, is presented below. This survey is part of a cooperative study with the . S. Forest Service, of the mine timber situation, with particular regard to the economies to be derived by better selection, preparation, and storage of timber, and especially treatment with preservatives to prolong the life. Geo. S. Rice, chief mining engineer of the J. S. Bureau of Mines, under whose general direction the work was done, gave valuable advice and criticism. R. B. Miller, State Forester, contributed helpful data which he had recent- ly obtained in an independent study of the mine-timber situation in Illinois.

Apr 1, 1923