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By E. A. Sondreal, P. H. Tufte

Flue gas desulfurization when burning western U.S. coals can be expected to be easier to achieve and less costly than when burning higher sulfur eastern and central coals. However, western coals cannot generally be burned in compliance with federal and state new source emission standards without some degree of control. Western coals and lignite represent about 20% of total U.S. recoverable reserves with 90% of that strip minable, and their production is predicted to increase from the 60 million tons mined in 1973 to 300 million tons in 1985. Most will be used for electric power generation, where low sulfur content is a paramount concern. Western coals are predominantly below 1% sulfur; low compared with typical values of 2 and 3% for eastern and central coals. Coal cleaning for removal of sulfur is not commercially practiced on Western coals, which typically contain half organic and half pyritic sulfur. A fraction of the pyrite sulfur could possibly be removed, but the

Jan 1, 1976

A novel method of reconditioning vertical rock openings which are on the verge of collapse has been developed, ant1 a world patent applied for, by LKAB, the Swedish iron ore mining company. Without anyone descending into the dangerous opening, workers can place concrete reinforcement in the unstable section using sand-filled canvas tubes which LKAR development engineers are calling "stockings." First application of the new technique was in several inclined ore pockets which form part of the underground crushing and loading station at LKAB's Kiirunavaara mine in Swedish Lapland. LKAB experience demonstrated that with other methods it took about three months to repair a pocket, and neighboring pockets had to be closed while repairs were underway. With the new stocking method, the work was completed in three weeks with no disruption of nearby activities. Production losses amounted to 10% over the three-week period, as opposed to 30% with other methods. The simplified technique could save millions of dollars in underground maintenance, according to LKAB.

Jan 11, 1978

By J. Wayne Erickson

Hundreds of millions of dollars have been spent to discover or purchase uranium resources that cannot, or should not, be mined with conventional methods if human, natural and financial resources are to be conserved. Three years ago, an industry-supported research stud was initiated to determine whether a safer and more efficient (in terms of cost and environment) uranium mining method could be designed to replace existing techniques. As a result of this study, the "underground in situ" method was conceived and developed to the stage where it is now feasible. This approach involves: (1) sinking a shaft; (2) driving a drift on the ore horizon the length of the ore body; (3) drilling almost-horizontal long holes the width of the ore body; and (4) oxidizing and leaching the uranium drawn from these holes. The method is unique in that the uranium is removed with a minimum of disturbance to the natural hydrology of host or surrounding sands.

Jan 11, 1978

All the TECHNICAL PUBLICATIONS and CONTRIBUTIONS published in 1935 are available at Institute headquarters, unless otherwise noted. They are also on file in many public, university and technical libraries and, when so indicated in the list, may be found in the TRANSACTIONS. Copies of the TECHNICAL PUBLICATIONS have been mailed to members of the Institute that are registered in the different classes: A-Metal Mining; B-Milling and Concentration; C-Iron and Steel Division; D-Nonferrous Metallurgy; E-Institute of Metals Division; F-Coal Division; G-Petroleum Division; H-Industrial Minerals Division (Nonmetallics); I-Mining Geology; J-Mineral Industry Education Division; K-Mining Administration; I-Geophysical Prospecting. Other members may obtain copies by writing to the Secretary. Copies of CONTRIBUTIONS may also be obtained from the Secretary's office. Additional copies are sold at the rate of 1 cent per page; minimum charge, 25 cents. Nonmembers may purchase the papers at the prices mentioned. [ ]

Jan 1, 1936

In situ mining is no longer a "last ditch" approach for recovery of uranium, but a proven and competitive method of exploiting sedimentary deposits. Today, in any feasibility study of uranium properties, the project manager would be prudent to compare the economics of in situ methods with conventional surface and underground techniques. In this comparison of in situ and open-pit mining, John J. Borkert and Carl E. Gerity of Occidental Minerals Corp., evaluated a group of hypothetical uranium deposits using the three most sensitive depositional characteristics of depth, size, and grade. Their conclusion: in situ is generally the better method to maximize total net profits and return on investment. At uranium values of $40 per pound, their analysis found open-pit mining to he unprofitable, generally, when stripping ratios were greater than 30:1, the deposit grade-thickness (GT) was 0.5 or less, or the ratio of depth to GT was greater than 200.

Jan 10, 1978

By D. G. Westlake

THE structure observed in thin foils by transmission electron microscopy is not necessarily representative of the initial bulk material. We have shown that hydrogen, originally present in a specimen of vanadium, niobium, or tantalum, can be concentrated by the thinning operation used to prepare foils from the bulk materials.' These foils exhibited domain walls indicative of a tetragonal distortion of the bcc unit cells, probably caused by ordering of the hydrogen in preferred interstitial sites. We believe this ordering does not occur at room temperature in the bulk material which contains less than 1 at. pct H. In a continued effort to prepare metal foils whose hydrogen concentrations remain constant during preparation, we have developed some new chemical and electrothinning techniques for vanadium. Each of the procedures presented in Table I produced foils that were thin enough for transmission electron microscopy. The experiments described below were performed to test the effect of each thinning procedure on hydro-

Jan 1, 1968

By George W. Lower, Robert B. Booth

The use of cyanides in the extraction of gold and silver is well known1 Such extractions employ concentrations of cyanide in the range of 0.02-0.25% sodium cyanide equivalent in leaching cycles of 24-48 hr and frequently longer. Copper minerals, even though minor components of precious metal ores, dissolve in these cyanide leaching solutions, consume cyanide, cause fouling of mill solutions, and thus interfere with the precipitation and recovery of gold.2,3,4 This paper presents a summary of laboratory investigations on the use of cyanide solutions as extractants for copper from various copper-bearing ore fractions. In view of the metal contents involved, it will be apparent that larger quantities of cyanide are required to extract copper than for the extraction of precious metals. In cyanide solutions of concentrations generally favorable to copper extraction, sulfide and oxide copper minerals were found to dissolve rapidly at room temperature and atmospheric pressure.

Jan 11, 1965

By William A. Bassett

Two very intense sources of electromagnetic radiation are contributing significantly to experimental studies of minerals at high pressures and temperatures: 1) A Q-switched YAG laser is able to produce a pulse of infrared radiation capable of heating a sample under pressures up to 400 kbar in a diamond cell up to temperatures in excess of 4000°C. 2) X-rays from the Cornell High Energy Synchrotron Source (CHESS) are used to obtain diffraction patterns of samples In a diamond cell in less than two minutes, patterns that would require hundreds of hours on a conventional source. The laser heating technique is being used to study the pressure-temperature conditions over which the melting of diamond takes place. In the initial stages of this investigation, diamond has been melted and techniques for detecting the melting have been developed. The intense X-rays from the synchrotron source have been used to examine the mechanism and rate of the pressure-induced phase transformation in Fe2Si04.

Jan 1, 1985

By D. C. Seidel, E. F. Fitzhugh

Nickel sulfide ores lend themselves readily to concentration before smelting or pressure leaching, but neither of the major oxidized ore types-the iron-rich laterites and magnesium-rich, soft silicates-has been directly concentrated. Upgrading of crude ore in current practice is limited to cobbing lumps of the harder, lower grade rock (protore) from the softer, enriched silicate ore, because only a small percentage of the nickel in these ores occurs in discrete, contrasting mineral particles. There is no apparent mineralogical contrast in the superficial, iron-rich lateritic ores and, in fact, there is no firm assurance that the nickel atoms are within the lattices of the limonite minerals, or else irregularly adsorbed on the limonite. Within underlying, "rotten rock" silicates, occasional veinlets of garnierite and related nickeliferous silicates are found.1 The garnierite veinlets are only incidental, and the majority of the nickel atoms occur as erratic replacements of magnesium atoms in the micaceous chlorites of the ore mass.

Jan 4, 1968

By L. E. Paulson

INTRODUCTION The Northern Great Plains has 16 billion tons of strippable lignite (1). Presently, 15 million tons per year are mined; essentially all is used for generation of electrical power. In the future, additional large quantities will be consumed in the production of gaseous and liquid fuels. A major consideration in design and operability of power stations and conversion plants is the nature of the ash or inorganic constituents of the lignite used. These inorganic components cause fireside fouling in boilers, exert a catalytic effect in liquefaction and gasification, and contribute to particulate and SO2 emissions. Ash fouling on fireside boiler tubes cause reduced heat transfer and gas flow which limits boiler performance. Severe fouling can result in shutdown of the boiler. A comprehensive test program in both pilot plant and field studies at the Grand Forks Energy Technology Center (GFETC) has shown that ash fouling increases with increased sodium content of low-rank coals (2). The sodium in the coal can be

Jan 1, 1983

By L. W. Bahney

Many methods for the determination of gold or silver, or both, in cyanide solutions have been published, which with care in manipulation, and modification in some cases, will give results that are satisfactory. It is possible to classify or group these methods as follows: 1. Evaporating the solution in a porcelain or agate-ware dish containing litharge,l or in a "boat" made of lead foil. 2. Forming a lead sponge containing the precious metals by means of zinc shavings,2 zinc dust,3 or a piece of aluminum.4 3. Decomposing the cyanide solution with an acid and precipitating the precious metals by the use of one or a combination of some of the following: Copper sulphate,5 sodium sulphite,6 hydrogen sulphide,' cement copper.ll 4. Precipitating the silver by zinc dust held in a Gooch crucible and determination with a standard solution of sulphocyanate.9 5. Electrolysis.l0 . 6. Colorimetry.ll

Jan 1, 1915

By S. W. Parr

STUDIES relating to the behavior of coal toward oxygen may have for their purpose the determination of the fundamental factors that underlie spontaneous combustion, weathering and deterioration, and the general topic of storage, as well as those properties that have to do with the underlying principles of carbonization. There is also involved the possibility of developing information relating to the constitution of coal, or at least the chemical properties inherent in the type substances of which the coal is composed. It is the purpose here to record certain FIG. 1. results bearing on this latter idea of the chemical properties that characterize the main constituents of bituminous coal. The avidity of freshly mined coal for oxygen has long been known. What happens to the coal or to the oxygen is not so clear. Is the oxygen absorbed or chemically combined, and what are the conditions as to time, temperature, texture, or components that are most involved in the phenomenon?

Jan 6, 1925

By L. A. Dale, D. A. Dahlstrom

Closed-water circuits are justified today from two standpoints: economical operation and prevention of stream pollution. In today's modern preparation plant, it has been found very desirable to have the plant circulating water maintained at a relatively low solids concentration of around 3%. In so doing, bene-ficiation equipment can operate at a much higher efficiency. However, makeup water requirements would become excessive if the fines were to be removed from the preparation plant by bleeding a 3% solids concentration to a tailings pond. With the ever increasing percentage of —200 mesh coal, clay and slimes in the raw coal, coupled with the creation of these fines within the preparation plant, the need for water conservation for economy reasons becomes even more important. Because of stream pollution laws, tailings ponds have become very costly to operate and maintain, resulting in the necessity of employing an in-plant method of water recovery. Accordingly, the primary system employed in water recovery in the coal preparation plant today consists of a solids concentration device to thicken refuse solids while at the same time producing a sufficiently clarified effluent that can go back to the preparation plant for water reuse. The thickened product is then normally passed to a dewatering device that will produce a handleable solid that can be disposed of

Jan 1, 1965

PRESIDENTS DAVID THOMAS 1871 R W RAYMOND 1872-1874 A L HOLLEY1875 ABRAM S HEWITT 1876 T STERRY HUNT 1877 ECKLEY B COXE 1878 - 1879 WILLIAM P SHINN 1880 WILLIAM METCALF 1881 RICHARD P ROTHWELL 1882 ROBERY W HUNT 1883 JAMES C, BAYLES 1884-1885 ROBERT H RICHARDS 1886 THOMAS EGLESTON 1887 WILLIAM B POTTER 1888 RICHARD PEARCE 1889 ADAM S HEWITT 1890 JOHN BIRKINBINE 1891-1892 H M HOWE 1893 JOHN FRITZ 1894 J D WEEKD 1895

Jan 1, 1923

(Under this heading will be published notes sent to the Secretary of the Institute by members or other persons introduced by members.) Experienced mining engineer, Columbia School of Mines graduate, practical experience in drifting, shaft sinking and development work, also in mining, operating and equipping iron, copper and zinc properties. Married, age 32, available at once. Open for position as superintendent or assistant. No. 462. Member, mining engineer, age 39, married, technical graduate, 12 years' experience in gold mining and milling; past four years as superintendent of large properties. At present employed but open for engagement after July 1; will consider no position not offering a future. Salary $4800. No. 467. Member, mining engineer, age 46, married, desires a position as superintendent, or an opening with an industrial company of permanency. Western and Alaskan experience in mining, cyanidation anti concentration. At present manager of an Eastern property, but desires a change. Available on thirty days' notice. No. 468.

Jan 7, 1918

On Jan. 1, Harvard opened its reorganized School of Engineering and will continue the work during the summer to enable the entrants to complete a full year's work by the opening of the next academic year in September. Some time ago Harvard University and the Massachusetts Institute of Technology agreed to combine effort in engineering instruction, making use of funds provided under the will of the late Gordon McKay. The agreement was objected to and the Massachusetts Supreme Court held that the arrangement was not in accord with the provisions of the will. The new arrangement has been approved both by the trustees of the McKay estate and by the governing boards of the university. Instruction will be offered in the following subjects; mechanical engineering, civil engineering, sanitary engineering, electrical engineering, mining and metallurgy, and industrial chemistry. Henry Lloyd Smyth has been appointed professor of mining and metallurgy, Albert Sauveur, professor of metallurgy and metallography, and Louis C. Graton, professor of economic geology.

Jan 2, 1919

By H. W. McCue, Henry Rogatz

Oil.—In the Texas Panhandle, during the year of 1941, 647 oil wells were drilled with a total daily initial production of 133,435 bb1.—that is, 145 more oil wells than in the previous year, with a decrease in total daily production of 5752 bbl. On Dec. 31, 1941, a daily allowable of 116,766 bbl., which was an increase of 27 per cent over 1940, was assigned to the field to be produced from 5182 wells. The total amount of oil produced for the year was 27,904,846 bbl., making a cumulative total of 404,657,324 bbl. during the past 20 years. Gas.—During the year, 52 gas wells were drilled, having a combined open flow of 2.62 billion cu. ft. per day—that is, 40 less than the number of wells drilled in 1940, with an increase in the open flow of 217,100,000 cu. ft. per day. The gas

Jan 1, 1942

By Henry Rogatz, H. W. McCue

Oil.—In the Texas Panhandle, during the year of 1941, 647 oil wells were drilled with a total daily initial production of 133,435 bb1.—that is, 145 more oil wells than in the previous year, with a decrease in total daily production of 5752 bbl. On Dec. 31, 1941, a daily allowable of 116,766 bbl., which was an increase of 27 per cent over 1940, was assigned to the field to be produced from 5182 wells. The total amount of oil produced for the year was 27,904,846 bbl., making a cumulative total of 404,657,324 bbl. during the past 20 years. Gas.—During the year, 52 gas wells were drilled, having a combined open flow of 2.62 billion cu. ft. per day—that is, 40 less than the number of wells drilled in 1940, with an increase in the open flow of 217,100,000 cu. ft. per day. The gas

Jan 1, 1942

By Telfer Norman

THE use of cadmium as a base for bearing metals is one of the most interesting recent developments in this field. It has caused a strong demand for cadmium and a marked rise in its price. It appeared to the authors, therefore, that the situation might be relieved for users if accept-able substitutes could be developed. A preliminary investigation has revealed that to some extent mercury may be substituted for cadmium. Whether its use is justified cannot be stated at this time. Most of the authors' work has indicated that the addition of mercury to alloys of cadmium and nickel detracts from their desirable physical properties; but this work has not been extended to cover service tests, which might reveal that the addition of low percent-ages of mercury to the cadmium-base alloys would improve their per-formance. The results of tests made by the authors are therefore briefly summarized for this paper. Table 1 gives the proportions of the metals

Jan 1, 1937

By N. L. Ananthanarayanan, J. F. Libsch

A LITERATURE survey1-' of sintering metal pow-A ders and powder compacts indicates that studies have so far been confined primarily to the latter stages of sintering in relatively coarse powders. Presumably this is due to the difficult techniques associated with studies of the early stages of sintering. Recent experimental and theoretical investigationsL-" on the preparation and the magnetic properties of ultrafine ferromagnetic powders suggest the possi- bility of following the sintering process from a very much earlier stage than has previously been considered. It is now well-known that ferromagnetic powder particles which are below a critical size behave as single domains and exhibit permanent magnet qualities characterized by a very high coercive force. When the same particles are fully sintered, the coercive force decreases to very low values corresponding to those of the solid metal. Thus the coercive force appears as a sensitive parameter which may be measured to study the early stages of sintering. To determine the feasibility of this technique, experi-

Jan 1, 1954