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By M. F. Williams, L. G. Hendrickson

In classification of pulps bearing magnetized ferro-magnetic particles, depolarizing is of great importance. If size separation is to be effective, particles must be individual rather than in flocs. Depolarizing is also practiced in heavy medium separations in which ferrosilicon or magnetite is the medium. When particles of ferromagnetic material have been removed from a magnetic field, residual magnetism causes agglomeration. The term depolarizing refers to the operation of reducing or eliminating this residual magnetism and may thus be considered magnetic deflocculation. The terms demagnetizing and randomizing are also used.

Feb 1, 1956

By John J. McKetta, Donald L. Katz

Recent experimental data on the methane-n-butane-water system have been combined with data in literature to present: (I) the water-vapor content of natural gases, (2) the solubility of water in hydrocarbon liquids, and (3) the solubility of natural gases in water. Since water is present in petroleum reservoirs, experimental data regarding the behavior of water in hydrocarbon-water systems is of increasing engineering importance. A survey of literature (Table I) shows that data of these types are fragmen-tary at temperatures above the hydrate region. Experimental data taken from the authors' recent investigation of the meth-ape-n-butane-water system are presented.17

Jan 1, 1947

By J. C. Draper, R. J. Houston, R. E. Pepperman

Duquesne Light Co. and CAI Consultants, Inc. conducted a demonstration program to establish permanent vegetative cover directly on acidic, deep coal mine refuse. Several plots were treated with formulas varying in soil amendment application rates and plant speak. Periodic monitoring of refuse chemistry indicated when maintenance applications of seed and soil amendments were required. To establish drainage control, the site had to be regraded. The most successful experimental formula was used as the bank for the formula applied to regraded portions of the site. Specific treatment for acidic spots has been initiated. Results of the program indicate that adequate permanent vegetation has been established.

Jan 1, 1985

By A. L. Hornbaker, S. D. Schwochow

Industrial minerals are becoming increasingly important in Colorado's mining industry, not only in production value but also in the variety available and in their potential development for both conventional and new uses. Fluorspar, building stone, fire clay, and pegmatite minerals have been historically important but are not now extensively mined. Aggregates (sand, gravel, and crushed stone), cement materials, metallurgical limestone, and common clays currently are the highest valued commodities. Those offering the greatest future potential include diamonds, nahcolite and dawsonite associated with oil shale, alunite, potash, zeolites, and rare earths.

Jan 1, 1982

By G. R. Fritterer

INVESTIGATORS in the field of temperature measurement have long sought a thermoelectric couple fulfilling the following requirements: 1. It should be useful up to and including high industrial tempera-tures; i. e., 1000° to 1800° C. 2. Its thermoelectric variation with temperature should be linear and be maintained after heating to high temperatures for long periods of time. 3. It should be reproducible; i. e., different couples of the same elements should have similar calibration curves. 4. Its thermoelectric power should be large so as to allow the industrial use of rugged recording instruments. 5. Chemical reactions with, and physical changes within the elements of the couple should not alter its calibration. No thermocouple proposed to date exhibits simultaneously all of these characteristics, whereas the couple about to be described fulfills all requirements to a satisfactory degree.

Jan 1, 1933

By B. M. Larsen

SEVERAL articles have recently been published discussing the conditions necessary for accurate measurements of temperatures in the open-hearth steel furnace. In the course of a study of refractories service conditions in steel furnaces, the present writers have taken tempera; tunes in several open-hearth shops in the Pittsburgh district. The conclusions, as to conditions necessary for accurate measurements of temperature, are somewhat at variance with those of other investigators. The subject is closely connected both with the close-control of steel-making and the prevention of overheating of the silica refractories used in roofs and walls. It is becoming more and more important to obtain furnace temperatures of fairly definitely known accuracy. At present, the most useful instrument for such measurements is the disappearing-filament type of optical pyrometer. This method of measurement has formed the basis of most other discussions on the. subject and was also used by the writers.

Jan 8, 1926

By Thomas M. Barczak, Claude A. Goode

Principal criteria in the design and operation of longwall mining systems are examined. The decision to apply longwall mining is investigated from an economic viewpoint, and the impact of economics on system design are addressed. Geological considerations and requirements for effective long- wall mining are provided. Ground control factors determining panel design are outlined, as well as environmental considerations. Operational practices are discussed and alternatives recommended. The impact of face moves and the potential for mining wider webs are assessed. Constraints to production are identified and the potential for increasing production of longwall systems is established.

Jan 1, 1982

By Mark S. Childs

FRIEDENSVILLE orebody in Lehigh County, Pennsylvania, lies in the south central part of the USGS Allentown Quadrangle. Physiographically the area is located in a small reentrant-known as Saucon Valley-of the Great Valley Province into the Reading Prong of the New England uplift. Saucon Valley itself is an oval-shaped lowland eight miles long and four miles wide, surrounded by ridges except where connected with the Great Valley through a breach in the rim known as Saucon Gap. These ridges, composed of Pre-Cambrian metamorphic rocks and Cambrian quartzites, rise some 500 ft above the valley floor. They are continuous with the New Jersey Highlands. The valley lowland is immediately underlain by lower Paleozoic dolomites and limestones. This area is one of low relief having a swing of approximately 100 ft, with an average elevation of 375 ft above sea level. The entire valley, which has a water shed of about 58 sq miles, is drained by Saucon Creek. This unit flows in a northeasterly direction to the Saucon Gap, where it discharges into the Lehigh River.

Jan 1, 1957

By C. L. Dake

Chemistry of Iron Solution IRON is much more soluble in the ferrous than in the ferric form. Where, as in the case of the ferrous silicates and the sulphides, the iron is already in the ferrous form, it may go at once into solution and be removed, upon the breaking down of the parent rock. If in the ferric form, it must first be reduced; usually by the decay of organic matter, the demand of the decaying carbonaceous matter for oxygen being so great that the latter is abstracted from the ferric compounds and the iron is thereby reduced and rendered' soluble. The iron may go into solution as the sulphate, or in the presence of excess CO2 as ferrous carbonate. It is probably soluble as salts of the organic acids.1 Recent work indicates that these are important in the formation of bog ores.2 There is considerable variety of opinion concerning the behavior of these organic compounds.3 The secretions about the roots of plants and trees also cause the solution and removal of iron and a consequent bleaching of the soil.4 While the matter is not yet well understood, we can probably say definitely that the so-called organic acids are a group of colloids which possess slightly acid properties, and the salts of which are partly soluble

Jan 7, 1915

By Thomas Fraser

Because of the present interest in the subject of sulfur in coal and its removal, such information as is available in the coal-washing literature on the various factors that determine the adaptability of a coal for wash- ing have been collected and are presented here together with some observations based on results of experimental work carried out in the coal-washing laboratory of the mining department of the University of Illinois, and investigative work at Illinois nrasheries in connection with the work on reduction of the sulfur content of coal, being carried on at the Urbana Station of the U. S. Bureau of Mines. This investigative

Jan 1, 1920

By George W. Lower, William A. Hockings, Donald A. Kaczynski

The rate of dissolution of polycrystalline metallic copper in aqueous cupric ammonium nitrate solutions in the non-film-forming region was investigated by the rotating disc method. The investigation was performed in solution concentration ranges applicable to hydrometallurgical processes. This investigation was an extension of a study on the cupric ammonium carbonate system previously reported by Smith, Lower and Hockings, in which the following kinetic model was proposed: (1) Diffusion of cupric ammine ions to the copper surface; (2) Forward reaction - first order reaction of cupric ammine ions with metallic copper; (3) Reverse reaction - disproportionation of cuprous ammine ions to metallic copper and cupric ammine ions ; and (4) Diffusion of cuprous ammine ions from the copper surface. The nitrate system was selected for this study because it simplified the determination of the ionic composition of the solutions. The variables studied were stirring speed and cupric, ammonia, and nitrate concentrations. The dissolution rate increased linearly with at low values of but exhibited increasingly negative deviations from linearity at higher values of m. The rate also increased with increasing cupric concentration but decreased with increasing ammonia and nitrate concentration. Good agreement was obtained between the experimental rate data and the proposed model. Further verification of the model was indicated by the close agreement of the diffusion coefficient calculated from the data and comparable literature values.

Jan 1, 1974

By Stuart St. Clair

IN view of the great interest shown in the oil possibilities of Kentucky, one is impressed with the paucity of reliable literature on the oil fields of the state. A few brief reports by the Federal and State Geological Surveys are about the only reliable data available. When the estimated production figures, for 1918, are published by the U. S. Geological Survey, they will show a revival of the oil industry in the Blue Grass State during the past half decade. There will also be an increase in the production for 1919 and 1920, at least. Although as an oil-producing state Kentucky is small, compared with sonic of the other oil states, the present production and the area of undrilled proved territory is large enough to classify it as one of the important oil states of the Union. This paper will be confined to the Irvine District and the immediately adjoining areas which have been prospected with varying success. The Corniferous limestone or Irvine sand is the oil-producing formation in the area discussed.

Jan 7, 1919

By Frederick Prime

AT the last meeting of the Institute, Mr. A. L. Holley read a paper on "Steel," in which he proposes for it a definition so opposed to the one generally received, as to call for some remarks. Until within the last five or six years there has been no dispute on the subject, and it seems worth while to investigate the matter. For not only does a proper tax on all importations depend on a proper appreciation of the term steel, but it is necessary to know whether steel, or wrought-iron, or homogeneous iron are requisite in all processes of manufacture in which malleable iron is employed, on account of cost, strength, etc. Karsteu* says : " Iron may be obtained, either as an unforgeable, unweldable metal, which melts at a high heat, termed cast-iron; or as a ductile, weldable, soft metal, which can only be melted at the * Karsten, Handbuch der Eisenhüttenkunde, 3d ed., vol. i, p. 6. Berlin, 1841.

Jan 1, 1876

By Gligorije Stankovic

This paper describes the fluo-solids roaster and acid plants at the new 40,000-TPY Trepca electrolytic zinc plant. The electrolytic zinc plant units were constructed to the design of Singmaster and Breyer, New York and began operation in mid-1967. The fluo-solids roaster plant, constructed according to the design of Dorr-Oliver, Paris, includes concentrate handling and storage facilities; two independent concentrate roasting circuits, each with a 110 to 155 TPD fluo-solids roaster; waste heat boilers; cyclones; electrostatic precipitators; calcine coolers; and calcine conveyors. The acid plant uses the "Petersen system" contact process. The plant has one acid circuit with a capacity of 230 tons of monohydrate per day. Gases for the acid plant are obtained from roasting zinc concentrates. When the roaster plant is operating at maximum capacity, excess SO2 is used in two other Petersen System circuits in the near vicinity.

Jan 1, 1970

Sec. 1. The membership of the Institute shall comprise six classes, namely: 1. Members; 2. Honorary Members; 3. Senior Members; 4. Associates; 5. Junior Members; 6. Rocky Mountain Members. All shall be equally entitled to the privileges of membership, excepting that no member of any class whom residence shall be outside of the United States of America, except those residing in Mexico and Canada, shall be entitled to vote. SEC. 2. Members: A person to be eligible for election or transfer into the claw of Member must be at least 27 years of age and must have had at least six years' employment in the practice of engineering, mining, geology, metallurgy, or chemistry, during at least three years of which he must have held positions of responsibility in one or more of these fields. This shall not apply to Rocky Mountain members.

Jan 1, 1939

By Rajaraman V. Ramani, K. Sinha Atmesh, Robert Stefanko

Use of electrical power in the bituminous mining industry has increased many fold during the last few decades. Rapid changes have also occurred in mine electrical power systems in order to meet the demands from highly mechanized mines. Fires, explosions, and deaths due to electrocutions are the primary hazards due to the underground use of electricity, although there has been a marked decrease in the fatality rate from electrical accidents. However, efforts to eliminate electrical hazards and to insure trained manpower for better distribution, utilization, and protection of the electrical systems cannot be relaxed. In this article, 200 fatal accidents that occurred during the period from 1955 to 1970 have been analyzed. Accident frequency has been correlated with the size of the mine and of the work force, and with age and work and task experience. A strong negative correlation has been established between task experience and accident frequency. Though the available data permitted only a limited analysis, need for improvements in electrical power technology and for better education and training has been identified and discussed. Missing information in accident statistics is outlined and suggestions for better hazard analysis are presented.

Jan 1, 1975

By Michael J. Bailey, Peter M. Douglass

INTRODUCTION Spoil pile slope failures can have costly consequences. In- stability in the form of a single major event or as a recurring problem can 'mean lost production, lost resources and damaged mining equipment. In extreme but not uncomnon cases, a major spoils slide can force the closure and abandonment of a pit. Slope stability is affected by mine operating practices as we1 l as geologic conditions and material parameters. Mine operators can enhance spoil pile stability through constructive changes in their operations. Attention to the causes of in- stability can lead to development of operating practices tailored to site specific problems. Action aimed at limiting future instability is frequently more cost effective than continually "coping" with unstable spoils. The effect of mine operations on material properties is often overlooked because the "data" are not easily quantified nor input directly into stability analysis equations. We have found, however, that miners' experience with their own operation, as well as data pooled from similar operations, yields relation- ships which can be utilized to solve stability problems. The repetitive nature of area type surface coal mines with successive spoil pile rows further enables the development of useful site specific relationships. Stability problems can be mitigated by applying these relationships.

Jan 1, 1983

By Peter L. Langsjoen, Kenneth L. Maloney

Ten small and intermediate-sized (4.5 Mg/hr to 113 Mg/hr steam--10,000 to 250,000 lb per hr) coal-fired boilers in the upper Midwest have each been tested on both a bituminous eastern coal and a subbituminous western coal. The purpose of this study was to determine the feasibility of substituting western subbituminous coal for eastern bituminous coal as a means of reducing the SO, emissions from this class of boiler and to demonstrate the feasibility of greatly expanded western coal utilization as a means of reducing the use of oil and gas. The scope of this study was such that the representative boiler types were tested on both eastern and western coal for a period of time sufficient to completely characterize their individual emission and operational characteristics.

Jan 1, 1978

By J. B. Goddard

In situ leaching of uranium by aqueous ammonium carbonate containing oxygen or hydrogen peroxide as oxidant results in the partial dissolution of sulfides. While some of the sulfide sulfur is oxidized to sulfate, a considerable portion is oxidized only to thiosulfate and polythionates. Polythionates poison the ion exchange resin used to extract uranium. At the Palangana operation in south Texas, the trithionate ion (S3062-) was found by infrared spectrometry to be the major resin poison. Treatment of ion exchange feed solutions with hydrogen peroxide only resulted in partial conversion of reduced sulfur species to sulfate. Trithionate conversion was particularly slow. Poisoning of the resin also occurred from the ammonium chloride eluant, which built up trithionate because of recycling. This was essentially eliminated by chlorinating the eluant before yellow cake precipitation.

Jan 1, 1986

By Homer E. Harris, William C. DeSieghardt, William A. Burgess

Under sponsorship of NIOSH, Eastern Associated Coal Corp., with the Harvard School of Public Health acting as a subcontractor, has determined for the first time the effective protection provided to working underground coal miners wearing approved half-mask dust respirators. This was done by conducting 187 man-shifts of in-mine testing in four different coal mines; included in this testing were 37 different test subjects representing 11 different job classifications and 5 different models of respirators. Presently available respirators on average provided significant protection levels to working miners even though on an intermittent use basis. However, "average" protection values were well below those achieved under laboratory conditions. Protection levels varied from man to man in a given work crew and from day to day for a given man. In addition, some of the factors affecting use and effectiveness of presently used respirators are discussed, as are areas in which improvements are needed, and the need to consider these improvements in context of a systems approach.

Jan 1, 1975