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By A. F. Baker, E. R. Palowitch, A. W. Deurbrouck

As air-pollution regulations become increasingly more stringent, increased significance is being placed on the amount of sulfur present in coals used for steam generation. These regulations are aimed at minimizing the pollution of the atmosphere with noxious gases such as the sulfur oxides that are formed and emitted when coal is burned. Two meet these future requirements, a definite need exists to reduce the sulfur content of some of the coals used for steam generation. Reducing pyritic sulfur involves liberating the pyrite from the coal and then removing it. The specific gravity of pyrite is high (5.0) compared to that of coal (about 1.2, mineral-free), and standard coal-washing devices, such as wet concentrating tables, will efficiently remove pyrite particles larger than about 100 mesh. Particles below this size will be entrained in the table water and will be carried into the clean coal product. Techniques such as froth flotation are of little benefit for pyrite reduction because the flotation characteristics of pyrite are similar to those of coal.

Jan 6, 1966

By Erwin Zodrow

An elaborate model for the magnetite distribution and genesis in the Smallwood mine, Labrador, based on factor analysis with orthogonal and oblique rotation of the factors, was proposed in an earlier paper. However, it is implicit in that model that variances of one variable shared with all others (communality) are estimated. To avoid the problem of communality estimation in the present investigation, a different type of factor analysis is used which (1) emphasizes the shared variances, and (2) attempts to eliminate, as much as possible, errors associated with the estimation of communality and sampling (unique variance). The samples for the present analysis are not the commonly employed oxide percentage variables, but counts of mineral species in specified areas of thin sections from drill core in the Smallwood mine: quartz, magnetite, calcite, and specular-hematite minerals. The counting procedure for mineral species is similar to modal analysis differing from it principally in the aspect of texture recognition. The constant area in which mineral species are counted is dependent primarily on

Jan 1, 1975

By Strathmore R. B. Cooke, Iwao Iwasaki

RECENTLY spectrophotometry has been reported to provide a convenient technique for the rapid and reproducible determination of xanthate concentration in pulp solution 1,2 and for a kinetic study of xanthate decomposition in acid solutions." Since the application of this analytical technique is feasible for those compounds showing pronounced light absorption maxima in the near ultraviolet region, it was deemed advisable to investigate the absorption spectra of some of the organic compounds that are used in flotation. It is known empirically that certain groups of atoms in an organic compound cause characteristic light absorption in the ultraviolet and near ultraviolet range, and the wavelengths and intensities of the corresponding absorption maxima are relatively independent of the nature of the remainder of the compound. The characteristic values of such groups, which are known as chromophores, are given in the literature. 4,5 According to this information, many of the sulphydryl compounds are expected to show absorption maxima in the near or long wavelength ultraviolet region, whereas the saturated fatty acids and the saturated alkylamines do not.

Jan 11, 1957

INTRODUCTION TO STATISTICS It is necessary now to digress from the direct study of appraisal techniques to consider an important tool for the mineral appraiser. Whenever a great deal of data have been accumulated, such as might be gained through the sampling process discussed in the preceding chapter, the application of statistical methods should be considered. Statistical methods are used for descriptive purposes and for the organization and summarization of quantitative or numerical data. Descriptive statistics covers the tabulation of data, its presentation in graphical or pictorial form, and the calculation of its several descriptive measures. It is not the intent of the brief summary of statistics that will be outlined hereafter to cover the total breadth and scope of mathematical statistics. It is the intent of this and the following chapters to review a few of the statistical concepts that have the most direct bearing upon the problems involved in mineral evaluation. Should the reader desire to go more fully into statistical theory and mathematics, numerous texts and publications are available.

Jan 1, 1980

By V. R. Garfias, R. V. Whetsel, J. W. Ristori

World consumption of petroleum and related fuels for civil purposes in 1939 was close to 2,024,000,000 bbl., or approximately 110,000,000 bbl. more than in 1938, the United States accounting for 96,000,000 bbl. of the increased amount. With the annexation of Czechoslovakia and part of Poland, civil consurnption in Germany during 1939, notwithstanding sevre rationing in the last four months of the year, was 54,000,000 bbl., or only 1,600,000 bbl. less than in 1938, and domestic production of pctroleum and related fuels was some 34,000,000 bbl. short of civil consumption. The mounting petroleum requirements of the military forces of greater Germany are, of course, not included in these figures of civil consumption. To supply this deficiency Germany now must rely almost exclusively on the Rumanian fields, which in 1939 produced about 35,000,000 bbl in ewes, of the Rumanian civil consumption. However, these fields arc supplying and have supplied for years the oil requirements of the neighboring

Jan 1, 1940

By S. F. Turcotte, B. J. Grierson

At the Q. I. T. ilmenite smelter, nine electric furnaces produce titania slag and iron At high power levels, a furnace requires either a slag or an iron tap approximately once an hour, using rail cars as slag receptacles and ladles for iron. The correct scheduling of taps is an important operational tool due to peak power load and operational considerations. Over recent years, large increases in furnace capacity have imposed severe strains on the product handling facilities. This situation results in loss of production when several taps are bunched, because of an in- ability to handle many taps simultaneously. An on-line computer program has been developed to generate schedules for tapping a single furnace. By improved scheduling, this program can en- large the tonnage of each tap and minimize the number of taps, while reducing traffic congestion and unit cost s. Future plans call for extension of this technique to all nine furnaces with addition of a master scheduling program to optimize the overall traffic flow in the smelter aisle.

Jan 1, 1969

By J. W. Ristori, R. V. Whetsel, V. R. Garfias

World consumption of petroleum and related fuels for civil purposes in 1939 was close to 2,024,000,000 bbl., or approximately 110,000,000 bbl. more than in 1938, the United States accounting for 96,000,000 bbl. of the increased amount. With the annexation of Czechoslovakia and part of Poland, civil consurnption in Germany during 1939, notwithstanding sevre rationing in the last four months of the year, was 54,000,000 bbl., or only 1,600,000 bbl. less than in 1938, and domestic production of pctroleum and related fuels was some 34,000,000 bbl. short of civil consumption. The mounting petroleum requirements of the military forces of greater Germany are, of course, not included in these figures of civil consumption. To supply this deficiency Germany now must rely almost exclusively on the Rumanian fields, which in 1939 produced about 35,000,000 bbl in ewes, of the Rumanian civil consumption. However, these fields arc supplying and have supplied for years the oil requirements of the neighboring

Jan 1, 1940

By Francis J. Dennis

Many factors govern the value of dredging-ground, and much capital can be wasted by the mistaken policy of contracting for the purchase of property arid the installation of machinery before a thorough examination has been made. To the uninitiated investor the presence of gold is generally the criterion, and very superficial evidence is necessary to satisfy him as to this point. he couuiclers the comprehensive report of a competent engineer as a wasteful extravagance, aild cannot understand why the engineer requires so much time and money to ascertain the information on which to base his conalusions, when the promoter can furnish him such pleaaing and satisfactory data with but little expenditure of time aud money. The uninitiated investor will often optimistically risk capital for purchase and equipment, and riot uiitil the veuture comes to grief does he learn that the condition8 are wholly unsuited for dredging. In many instances, a short preliminary examination by a competent engineer would have disclosed these facts. The mere presence of gold is by no means suficient; sonie of

Jan 1, 1912

By V. Annamalai, J. B. Hiskey, L. E. Murr

The kinetics of copper cementation on rotating disks of body and tear-top beverage can aluminum alloys were studied as a function of temperature and copper ion concentration. Both alloys followed the two-step kinetic regions, an initially slow rate followed by an enhanced rate. Experimental activation energy determinations (9.04 to 19.62 kJ/mol) indicated that ionic diffusion controlled the reaction mechanism between 20° and 60°C. At low temperatures (< 20°C), the system appeared to be controlled by the presence of an aluminum oxide surface film. The results of this study showed that cementation kinetics for the beverage can aluminum alloys are similar to those for pure aluminum. It was also found that the chemical removal of the oxide layer is less important for the alloys than /or the pure aluminum system. The characteristics of the resultant copper deposits were studied under a scanning electron microscope, and the reaction kinetics seemed to depend strongly on the nature and morphology of the deposits. In addition, maximum rates occurred when the deposit structures were fine feathery dendrites.

Jan 1, 1980

By Graham Swan, Ove Alm

In-situ fracture toughness experiments have been performed with a scanning electron-microscope. The rock, Stripa granite, was loaded both in tension and three-point bending using the same size notched plates. Observations, which included crack extension measurements as a function of load, are presented in the form of R-curves. The data does not sup- port the proposition that R-curves can be regarded as independent of specimen configuration for this granite. Typically crack extension was seen to begin at loads of 70-80 % failure load. Tensile specimens showed considerably greater sub-critical crack growth than the bend specimens. Evaluation of the approximate fracture toughness Km for both specimen types produced as expected erroneously low estimates Of KIC, being worst in the case of the tensile specimen. Some crack extension data for Stripa granite using the indirect methods of compliance calibration, fluorescent dye penetrant and acoustic emission are compared. In a material such as Stripa granite it is considered that no single method is without its limitations.

Jan 1, 1982

By F. D. DeVaney

IT is of great interest that the various organizations engaged in the search for a cheap and efficient agglomeration process for fine magnetite concentrates-essential if the taconites are to be utilized-have ended up with processes that are basically different. This paper describes the development and the present status of the shaft-type furnace as now utilized by the Erie Mining Co., which is managed by Pickands Mather & Co. The shaft furnace has always had an appeal to metallurgists because of the simplicity of the design and the possible low fuel consumption. Work done on pelletizing at the University of Minnesota Mines Experiment Station by E. W. Davis and his associates determined that it was possible to roll up fine magnetite concentrates in a balling drum, and that, if such balls were fired at a sufficiently high temperature, a hard, indurated pellet, well adapted for use in a blast furnace, could be made. Early furnaces had no heat recuperation and the heat consumption was in the order of 2 million BTU&apos;s per long ton.

Jan 3, 1958

By Joseph A. Sutton, John D. Corrick

The continuing depletion of high-grade ore de- posits in this country has created a need to develop more effective methods for recovering valuable metals from low-grade ores. The use of microorganisms for their biochemical reactions is one possible way to solve certain phases of this problem. Bacteria have been used successfully by many diversified industries. Until recently, however, little attention has been focused on the use of bacteria in mining and metallurgical processes. This report summarizes one phase of the microbial studies being conducted at the U.S. Bureau of Mines, College Park Metallurgy Research Center. The two-fold objective of this study was, first, to determine if pure strains of the bacteria Ferrobacillus ferrooxidans, Thiobacillus concretivorus and Thiobacillus ferrooxidans could utilize the iron and sulfur occurring in sulfide minerals to produce appreciable quantities of ferric sulfate and sulfuric acid for dissolving copper and, second, to develop the chemistry involved in the microbial oxidation of sulfide minerals. These are of particular interest as they relate directly to the feasibility of employing microorganisms in leaching operations.

Jan 6, 1963

By W. C. Lacy

The last crop of graduates from our colleges and universities who sought employment in the mineral industries found that they needed to hustle to find a job. There was no longer a list of waiting employers to choose from. Some of them became discouraged and drifted into other fields; many are still looking for employment. Word has gotten around that there are no jobs available in the mineral industries, and enrollment in the various colleges of mines and mineral industries has started to drop. Even established professional men are finding themselves suddenly out of work because of unstable metal prices and rising costs. All these people-students beginning to search for a career, young engineers not yet established-face the same problem: "What is the future of the mineral industries, and what type of training will best qualify the scientist or engineer for this changing field?" This question was posed to a number of leaders in different phases of the industry. Their comments are summarized as a guide to those considering a career in the finding, extraction, or beneficiation of mineral products.

Jan 1, 1960

By Edward C. Roper

Pegasus&apos; Gold Ltd. operates two gold/silver heap leaching operations in the Little Rockies area of Montana. The Little Rockies has produced gold from underground operations on an intermittent basis from the 1880&apos;s to the early 1950&apos;s and from the open-pits on a continuous basis since 1979. Run-of-the-mine ore is drilled, blasted, sorted, loaded and hauled. The waste is dumped and compacted into 30 meter (100 foot) fills to be used for future leach pads. The leach pads have a central drain system and the impermeable membrane is constructed of bentonite and 30 mil PVC. The plants which have beenexpanded to 4900 Ipm (1300 gpm) capacity use the Merrill-Crowe process for gold and silver recovery. 4600 liters (1200 gpm) of the 9500 Ipm (2500 gpm) spray capacity is recycled through the old leach pads for upgrading before being processed. The gold/silver precipitate is smelted and the resultant dore&apos; is shipped to a buyerhefiner. 1983 projected production is 2,177 kg (70,000 02s) of gold at a cost of less than $10/gm.

Jan 1, 1984

By Jerrold Marcus

The peninsula is roughly 700 miles long and 180 miles wide. The southern portion is the American-sponsored Republic of Korea and the northern half is the Soviet-promulgated People&apos;s Democratic Republic of Korea. The area of South Korea is almost 40,000 sq miles, about the size of the state of Maine, and contains a population estimated at 22.5 million. Prior to annexation by Japan in 1910, the Korean economy was based on a system of self-sufficient farming units, but with Japanese occupation it was geared to Japanese economy. Emphasis was placed on supplying raw materials for Japanese industry and food surpluses to help feed Japan, and on providing a connecting link with Manchuria, traditionally a major raw material source for Japan. Small metal refineries, ore processing, and semi-finished goods manufacturing units grew into existence in the northern part of Korea, where much of the electric power is generated. Under Japanese domination, the south remained essentially agricultural. Food productivity was increased, although manufacture of elementary consumer goods was stimulated for Japanese markets.

Apr 1, 1956

By Morris Muskat

THE method of R. W. Moore1 for determining subsurface interfacial depths by means of integrated curves of apparent resistivity has been analyzed theoretically. It is found that the only unique tangents that can be drawn to such curves are the asymptotes at infinite electrode spacing and the tangents through the origin at vanishing electrode spacing. Explicit expressions have been derived for the relationship between the electrode spacing at the points of intersection of these tangents and the thickness of the surface strata as a function of the conductivity parameters for the two-layer and three-layer earths. It is found that in all cases the electrode spacing at the points of intersection will exceed [3/2] of the thickness of the surface layer, and may even become indefinitely large as the resistivity of the deepest layers increases as compared with that of the surface layer. These results do not agree with the empirical findings of Moore that the intersection of the tangent lines fall at an electrode spacing very approximately equal to the thickness "of the surface layer.

Jan 1, 1944

By J. Donald Graham, John G. Kuhn

The goal of any development drilling program is the drilling of the exact number of holes necessary to adequately determine grade and dimensions of an ore body, no more and no less. Any technique which eliminates unnecessary drilling costs produces beneficial results, both to the company and to the person who can claim the savings. The method for controlling development drilling programs to be described was developed during the latter part of a major development drilling project at the Christmas mine of Inspiration Consolidated Copper Co. in Gila County, Arizona. It was used to test the need for drilling individual holes but could be expanded to control an entire project. Application of this method involves an evaluation of geological conditions present and a good bit of common sense. Projects involving large disseminated, rather homogeneous ore bodies of the porphyry-copper type would be the most likely candidates for application of the technique. Discontinuous ore bodies would not be amenable. The method is based on the measurement of the linear correlation between the spatial distribution of two sets

Jan 1, 1973

By James A. Carney

The quality of water for steam boilers is a serious question in Illinois, and has been the occasion of many investigations, undertaken either for the discovery of sources of a better supply, or for the purification of the supplies already at hand. LOCATION OF SUPPLIES. The sources of supply of which this paper treats lie along the right of way of the Chicago, Burlington and Quincy Railroad Company, and form a nearly straight line from Chicago, Illinois, on Lake Michigan, to Burlington, Iowa, on the Mississippi River. The supplies consist of surface-, ground- and deep well-waters ; their locations are given in Fig. 1, which is adapted from a map of Illinois published by the Illinois Railroad Commissioners. The influence of the geological formation on the water-supply of Illinois is fully treated in an article in the Seventeenth Annual Report of the U. S. Geological Survey by Mr. Frank Leverett, entitled, " The Water-Resources of Illinois." It is not the purpose of this paper to introduce a geological discussion; and

Jan 1, 1898

By N. J. Grant, F. B. Cuff

DURING a recent investigation of high-purity aluminum,&apos; evidence was found for grain-boundary sliding and migration at room temperature. The investigation was concerned primarily with an electron-microscopic study of a fine (approximately 1 micron) network that appeared on the surface of chemically polished aluminum. The nature of the network will not be discussed since it serves only as markers showing relative displacements in this instance. The pertinent observation, shown in Fig. 1, was made on a flat tensile specimen which had been strained about 8 pct at room temperature. As can be seen in this electron micrograph, a grain boundary has undergone a certain amount of sliding. The reason for the existence of the two differently appearing networks is given in the foregoing reference. For present purposes, however, the transition region can be disregarded. A close study of this picture reveals that in addi- tion to sliding there is a narrow band adjacent to and above the grain boundary. Fig. 2 is a schematic drawing showing the essential features of this band.

Jan 1, 1959

By A. L. Senkayi, L. R. Hossner, J. B. Dixon, J. S. Ahlrichs

Chemical and physical properties of soils and overburden materials must be evaluated prior to strip mining activities. This information can be used to assess whether subsurface overburden can be equal in quality to the native soils, especially when these soils are classed as prime farm lands. In northeast Texas, lignite primarily occurs in the Calvert Bluff formation which is underlain by the Simboro and Hooper formations. These formations are in the Wilcox group (early Eocene). The Carrizo formation, that unconformably overlies the Calvert Bluff formation, consists of thick layers of sand with poor water and nutrient retention capabilities. These materials are least suited for placement on the surface of reclaimed land. The oxidized, medium textured overburden of the Culvert Bluff and Simboro formations possess adequate water and nutrient retention properties and are better suited for sustained plant growth when compared to the existing native soils. Non-oxidized Calvert Bluff and Hooper sediments generally have acceptable properties for reclamation although acid forming sulfides occasionally occur. Materials high in sulfides must be buried during mining or appropriately treated prior to reclamation.

Jan 1, 1984