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Jan 1, 1934

By S. K. Kawatra, R. A. Seitz

Various mathematical models and expressions to describe the behavior of a hydrocyclone have been presented in the literature (Lynch and Rao, 1977; Plitt, 1976; Plitt and Kawatra, 1977). Two of these models, by Lynch (1977) and by Plitt (1976), have been extensively used for process control studies (Kawatra and Thayer, 1879; Seitz and Kawatra, 1984). However, neither of these models relates the fineness of grind in a hydrocyclone overflow to the corrected efficiency curve of a hydrocyclone. If such a relationship were available, then one could relate fineness of grind to the operating variables using equation (1) or (2). A plant metallurgist is interested in knowing the fineness of grind rather than the dso(c) of a hydro- cyclone. As a consequence, several empirical relation- ships between fineness of grind and hydrocyclone operating variables are available. These relationships (Fewings, Wickham, and Wiseman, 1979; Manning, 1978; Watson, Cropton, and Brookes, 1970; Watts, Thompson, and White, 1978; Wiegal, 1973) have only a limited relationship with each other and have met with varying degrees of success. The object of this paper is to develop a fundamental relationship between fineness of grind and the efficiency curve of a hydro- cyclone

Jan 1, 1986

WHOEVER has occasion to judge tin in its whiteness from the testimony of his eyes alone would surely believe it to be purest silver, or something that comes very near to it in nature. This is even more so when, on handling, it is found to be harder than lead, to which it can be said to have a greater and closer resemblance. But whoever has actual experience with tin knows that none of the other metals is less similar to it than silver. For silver mixes with every metal, as does gold; and they unite together, and the others do likewise; and except for their color they change their natures but little. But this metal tin, wherever it is found, acts like a powerful poison which envenoms and corrupts the others; and it does this not only with large quantities but also with every small amount; indeed just the trace remaining where it has been melted is enough to embrittle silver and gold as well as iron and copper. The greater the quantity of it in these, the greater are its effects. Speculators of natural causes say that this fact arises from its great wateriness, which is very subtle and poorly decocted and almost like that of quicksilver. This wateriness, then, by means of its subtlety which joins itself with metals, imposes itself into that unctuous and viscous material which renders them flexible, and thus deprives them of their toughness

Jan 1, 1942

By W. R. Ingalls

DURING 1921, the Oklahoma mines dominated the American zinc-producing industry. They comprised the only group that could produce under the adverse conditions that prevailed. At the beginning of 1921, there were about 34 mills in opera-tion in the Tri-state District, out of a total estimated variously at 150 to 200, and these were producing at the rate of about 5000 tons of blende concentrate per week. At the end of 1921, there were about 50 mills in operation. The Tri-state District rates about 80 men to the mine and mill, on-the average. SMELTING The zinc smelters-in 1921 experienced a disastrous year. All of them operated at greatly reduced capacity and probably most of them suffered loss in operations. Smelting costs came down to a considerable extent by virtue of drops in the price for coal, wage reductions and more efficient work, but these ameliorations were insufficient to enable the smelters to come out even. In the Illinois fields, wages at the end of 1921 had been reduced about 37 per cent. from the peak (middle of 1920), but coal continued to be very dear. The operation of works at a low rate of their capacity was a discouraging and expensive condition. At the end of 1921, the zinc-smelting capacity ,of the United States was as follows:

Jan 7, 1922

By Rush Sill

THE processes of superficial alteration depend on physical conditions, environment, geologic history and chemical and mineralogical composition. Superficial alteration is confined particularly to the zone of shallow circulation, as this is the zone of solution; its rocks are open and the circulation within it is compara-tively rapid. The enrichment of ore deposits in this zone, therefore, is of special interest. The depth of the vadose, or zone of shallow circula-tion, is variable, because its lower limit depends on the variable level of ground water. In moist, hilly countries its depth varies from a few feet to several hundred feet. In arid regions where the rainfall is low and evaporation great, this zone may extend to much greater depths. Permeability of the deposits . is essential to the downward migration of metals. In rocks, that have been fractured since the primary ore was deposited, there is generally more extensive and deeper enrichment than in ore deposits that have been but slightly fractured. A warm climate increases chemical action and abundant rain fall is favorable to enrichment. Low relief and slow erosion give long periods of weathering and thorough leaching.

Jan 9, 1922

By J. C. Irvine

Meramec Mining Co., a joint venture by Bethlehem Steel Corp. and St. Joe Minerals Corp., is engaged in the mining, concentrating, and pelletizing of iron ore from the Pea Ridge mine near Sullivan, Mo., about 70 mi southwest of St. Louis. The orebody lies under about 1300 ft of sediments. It is tabular, about 2600 ft long and up to 600 ft thick, and lies in an approximate east-west delineation. The orebody dips about 80"s and is of unknown depth. The ore is primarily high grade magnetite with smaller zones of specular hematite. The Precambrian wall rock is rhyolite porphyry. The mine is serviced through two concrete-lined shafts, 19 ft 1 in. diam and 2500 ft deep. No. 1 shaft, equipped with an "A" type head-frame and conventional cylindrical drums, hoists men, materials, and waste rock; it is also the downcast air shaft. No. 2 shaft utilizes tower-mounted friction hoists to handle the two production skips, each with 24-ton counterweights, and a small man cage. The mine exhaust passes through this shaft. Ore is principally mined by sublevel stoping,

Jan 9, 1972

Pennsylvania has been a leader in the pageant of industrial America because of her natural mineral re- sources, geographical location, and the ingenuity and industry of her citizens. Brick and other clay products were manufactured in Philadelphia in William Penn's time. Ores of iron, zinc, lead, and copper were mined and smelted in eastern Pennsylvania long before the Revolution. Coal was mined on a commercial basis in the anthracite region as early as 1820 and in the bituminous fields in 1830. The first canals and railroads were constructed to transport minerals and mineral products. Oil was struck at Titusville in 1859. A significant event occurred in 1855-the establishment of the Farmers' High School-Pennsylvania's first attempt to provide higher education for its youth. The Farmers' High School included instruction in geology, mineralogy, and assaying. In 1859 the laws of Pennsylvania transferred to the School the state geological and mineralogical collections formerly located in Harrisburg. Well-informed people are familiar with the effects of the Land-Grant Act of 1862. With inspiring words it established state institutions of higher learning where "the leading object shall be, without excluding other scientific and classical studies . . . to teach such branches of learning as are related to agriculture and the mechanic arts . . . in order to promote the liberal and practical education of the industrial classes in the sev-

Jan 1, 1950

By E. W. Lithgow, E. G. Williams, R. R. Holbrook, B. R. Wilson

The mineralogy and geochemistry of Pennsylvanian shales and underclays were studied to determine their suitability for lightweight aggregate and refractory ladle brick. Eighty percent of the variation in bloating of shales and clays was explained by the variation of Si02, A1203, and fluxes (Fe203, MgO, CaO, Na20, and K20); 60% by variation in quartz, kaolinite, illite, and chlorite. The best bloating was exhibited by marine shales, whereas freshwater shales and underclays experienced little or no expansion. Regional paleogeographic maps o f Pottsville and Allegheny shales permit bloating to be geographically predicted. It was found that clays meeting the specifications for refractory ladle bricks were obtained from underclays having over 34.5% mica, over 40% kaolinite and less than 15% quartz. Underclays of this composition are confined to the lower Allegheney outcropping along the near-margins of the coal basin. The best clay is that underlying the Lower Kittanning coal. Porosity of the first fired brick was found to be inversely correlated with reheat expansion.

Jan 1, 1975

A group of prominent engineers and contractors of Chicago and vicinity have cooperated in forming a Joint Committee on Military Engineering. The founders are members of all of the leading engineering and contracting organizations of Chicago, including the local branches of the national engineering societies. The purposes of the Committee are to further military preparedness among engineers, contractors and their associates by the following means: (1) Courses of lectures; (2) assigned reading; (3) studies and practical instruction in military engineering;. (4) assisting engineers to qualify as officers in the National Reserve Corps of Civilian Engineers; (5) urging enlistment in and support for engineer troops of the National Guard and such other organizations as the Government may create; (6) furthering instruction in military engineering in training camps and the attendance in them of those qualified; (7) by such other means as from time to time may be deemed advisable. The Joint Committee has already prepared a program covering the vital points outlined. To date the program is practically complete for a period extending from April 20 to July 25. Something of interest will be taken up each week, including lectures by Lieutenant-Colonel W. B. Judson, Engineer Corps, U. S. Army; two lectures by Major P. S. Bond, Engineer Corps, U. S. Army; Lieutenant-Colonel Mason M. Patrick, Engineer Corps, U. S. Army, and several exhibition drills, terrain exercises and inspection trips under the direction and guidance of various officers of the Engineer Troops of the Illinois National Guard. Additions to the program will be made from time to time. '

Jan 5, 1916

The Fifth Annual National Exposition of Chemical Industries will be held in Chicago at the Coliseum and First Regiment Armory during the week of Sept. 22. It was decided to hold the exposition in Chicago, this year, for two reasons: The U. S. Army commandeered the Grand Central Palace Exposition Building in New York, immediately on the close of the last exposition and converted it into a receiving hospital, the use for which is now, happily, nearly ceased; and it was thought that the Exposition would succeed in bringing about a greater development of chemical industries in the Chicago district and the adjoining states. The Advisory Committee of the Exposition consists of: Charles H. Herty, Chairman, Editor Journal of Industrial and Engineering Chemistry; Raymond F. Bacon, Director, Mellon Institute; L. H. Baekeland, Member Naval Consulting Board; W. D. Bancroft, President, American Electrochemical Society; Henry B. Faber, Industrial Filtration Corpn.; Ellwood Hendrick, President, The Chemists' Club; Bernard C. Hesse, Chemist, General Chemical Co.; A. D. Little, President, Arthur D. Little Inc.; Wm. H. Nichols, President, American Chemical Society; R. P. Perry, Vice-president, The Barrett Co.; H. C. Parmelee, Editor Chemical &; Metallurgical Engineering, G. W. Thompson, President, American Institute of Chemical Engineers; T. B. Wagner, Vice-president, U. S. Food Products Corpn.; M. C. Whitaker, President, U. S. Industrial Chemical Co.; and Charles F. Roth and Fred W. Payne. There is also added a special Chicago committee consisting of L. V. Redman, W. D. Richardson, A. V. H. Mory, Carl S. Minor, F. W. Willard, and Wm. Hoskins; the managers, as in the past, are Charles F. Roth and Fred W. Payne.

Jan 6, 1919

Where Does the Mine Dollar Go? BY PAUL M TYLER (Min & Met, April, 183 3900 words) Wage earners on the job get nearly 50 per cent of the mine dollar; salaries normally take over 5 per cent (less for large metal mines); and less than 20 per cent is expended for supplies, materials, fuel, and power The total of all such specified expenditures, which may be loosely described as "direct costs," has tended over several decades to decline from over 75 per cent to under 70 per cent of the gross receipts from the sale of products of mines and quarries The item of supplies and material is far less important in the extractive industries (mines, forests, and fisheries) than in manufacturing For manufactured products the average cost of raw materials was 30 4 per cent of gross sales, almost double the proportion for the mineral industries, whereas factory wages and salaries accounted for only 33 2 per cent instead of 51 9 per cent Within reasonable limits, the margin above direct costs as herein calculated affords a measure of capital's share in the total realized from sales A preponderant group of mineral industries operate under conditions that permit or require a margin of 25 to 45 per cent At one end of the scale are highly organized industries such as sulfur, fuller's earth and iron ore mining employing much

Jan 1, 1935

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Jan 2, 1969

By Roy P. Hudson

A micropyrometer known as the De Graaf apparatus has several advantages over the gas-furnace method for determining ash fusibility. When the De Graaf apparatus is operated by a modified method of procedure, the results closely check those of the gas-furnace method. This is indicated by tests on 27 samples of coal ash, with an extreme variation in fusibility values of 654" F. However, most of the ashes fused at temperatures between 2300º and 2500º. This, presumably, is the temperature interval within which the micropyrometer gives the best results. Additional comparisons are desirable. DISCUSSION (Thomas G. Fear presiding) A. C. FIELDNER,† Washington, D. C. (written discussion‡).-—The Pittsburgh Experiment Station of the Bureau of Mines has made two investigations1 of the micropyrometer for determining the fusibility of coal ash. These studies were undertaken with a view to adopting the micropyrometer method us a substitute or alternate to the present standard gas-furnace method, in view of the obvious advantages of greater speed, smaller ash sample, smaller laboratory space requirements, less equipment and greater comfort to the operator. However, the investigation showed that the micropyrometer type of furnace as then operated in five laboratories having this equipment could not be accepted as an alternate to the standard gas furnace, which is capable of close duplication in different laboratories, as shown in a recent colmparison between the Pittsburgh Experiment Station of the United States Bureau of Mines and the Fuel Research Station of Great Britain.2 The algebraic meau

Jan 1, 1934

By S. P. Goplen, M. Henriksen, T. F. Barron

In the past decade, numerous large scale drilling projects have made use of reverse circulation air lift methods. Reverse air lift pumping can be established by injecting gas into a column of liquid; the subsequently decreased density of the gas-liquid mixture allows atmospheric pressure outside the lift conduit to establish flow. The rate of flow can be controlled by varying the gas to liquid ratio. A typical reverse circulation air lift system is depicted in [Fig. 1]. Allen 1 has described a number of reverse air lift drilling projects. Although cited examples are generally related to large diameter holes, the method has seen use in other applications such as sand dredging, chemical pumping, water well pumping. and continuous coring. One particular benefit obtained with enclosed reverse circulation drilling is elimination of lost circulation. The required air/water ratio for pumping at a given submergence and lift has been established experimentally by Gibbs.2 His data, however, do not reflect sensitivity of flow rate to air/water ratio. Further, in Gibbs' work, air apparently is injec-

Jan 1, 1980

By Molly Gleiser, John Chipman

The standard free energy of formation of WC was obtained from determination of the equilibrium WC + CO2 = W + 2CO between 1215° and 1266°K. Its uallie is -8340 * 300 cal Per mole over the above range of temperature. AS a part of a program devoted to measuring the stabilities of the carbides, a study was made of the free energy of formation of tungsten carbide, WC. The homogeneity range of this compound is very small,' and it is generally accepted and is dealt with here as a stoichiometric compound. The heat of formation, ?H°f, of WC has been accurately measured by Huff, Squitieri, and snyder.2 The only attempt, however, to measure the free energy of formation of this compound was made by Schenck, Kurzen, and wesselkock3 who brought tungsten carbides into equilibrium with H2 and CH4. Unfortunately their results are not sufficiently accurate nor consistent enough to permit the calculation of free energies. METHOD Heating mixtures of tungsten and carbon powders in hydrogen for 4 days at 1050°C led to formation of some WC without any trace of W2C. It was deduced, therefore, that at least below this temperature W2C will not be formed during experiments with mixtures of tungsten and WC. This was subsequently shown to be correct. The method chosen was the measurement of the equilibrium of the reaction

Jan 1, 1962

1. Healthy and active Local Section organizations are vital factors in promoting the vigor and growth of the Institute. 2. Activity on the part of Local Sections should be recognized and stimulated by appropriation of funds from the Institute's treasury; and these appropriations should be as large as is consistent with the relative needs for other activities. 3. As between different Sections, the amount of such appropriations should be based primarily on the extent of activities as reflected in the number and character of meetings held and the attendance of the members at such meetings. 4. In making a request for funds for any year, the officers of a Local Section should submit a report on the printed form approved by the Directors at their meeting on November 19, 1937. 5. A standing Committee on Local Section Appropriations, consisting of one past Chairman of a Local Section, one member of the Institute's Executive Committee, and one member of the Finance Committee, shall be appointed by the President and shall pass upon requests for appropriations and authorize payments within bounds of the budget. The committee will be guided by the principles herein outlined, always having in mind the vital importance of healthy, active Sections to the welfare of the Institute as a whole. 6: According to Article XI, Section 2 of the Bylaws, requests for appropriations shall be signed by the Chairman, Secretary and Treasurer of the Section. 7. Requests for appropriations must be in the hands of the Secretary of the Institute by February 15 of the year for which they are desired.

Jan 1, 1946

By W. J. C. Venter

The use of activated carbon to improve the selectivity in the separation of base metal minerals from bulk concentrates played an important role in the development of separation techniques employed at Tsumeb and Kombat mines. The Kombat mine, owned and operated by Tsumeb Corp. Ltd., is located in the Otavi Valley in the northern part of South West Africa, approximately 213 air miles north of Windhoek and 38 air miles south of Tsumeb, at latitude 19° 43'S and longitude 17º 41'E. The mine is linked to all major centers by both national railroad and tarmac highway systems which pass right through the town. The Otavi Minen- and Eisenbahn-Gesellschaft (OMEG) mined ore on the farm Asis from 1908-1925. Tsumeb Corp. Ltd. acquired the mineral rights in 1947, started diamond drilling in 1954 and commenced mine development in 1960. The mill started production in 1962 when proven ore reserves were 3,378,084 st containing 2.85% Cu and 2.90%Pb. Annual production of 248,411 st was increased in May, 1967 to the rate of 422,990 st, which was still being maintained in 1971, when ore reserves stood at 3,054,701 st of grade 1,91% Cu and 2.5% Pb.

Jan 4, 1973

By William P. Blake

The copper-beariug rock formations of Cananea, Sonora, Mexico, present conclusive evidences of extensive and sharp plication. Some of these evidences are here briefly stated. 1. There is a succession of approximately parallel outcrops of an altered limestone, alternating with dikes and masses of porphyry. The great copper-ore deposits are in close association with these ridges of limestone, which trend northerly and southerly and stand nearly vertical. This parallel succession is so well-defined that the management of the mines has, for convenience, recognized and named five zones, known from the chief mines, in their succession from east to west, as the " Cobre-Grande," " Veta-Grande," " Esperanza," " Capote," and " Puertocitas " belts. The intervening and separating formations are coarsely crystalline feldspar porphyries, highly basic, of light color, which may be regarded as intrusive and, in part at least, as the cause of the metamorphosed condition of the limestone. 2. These cupriferous limestone-zones are similar in constitution, are similarly charged with copper-ore (in association with quartz as a gangue, or veinstone), and are marked by similar croppiugs of gossan. 3. Distinctly folded outcrops of the surrounding strata can be observed, especially on the eastern border of the copper-bearing district north of the Democrita ground, and not far from the Veta-Grande. 4. The limestone ridge adjoining the Veta-Grande ends a short distance north of the mine, and appears to be the extretne end of a synclinal trough. 5. The Capote limestone, the most western of the croppings of the central copper-bearing area, is contiguous to stratified sandstones and quartzites, uplifted at high angles, but showing an easterly dip. The Capote limestone is apparently conformable

Jan 1, 1905

By T. M. Allen, W. H. White

THE Greenwood-Grand Forks area of southern central British Columbia, known as the Boundary District, has a long history of mining exploration and production. At the turn of the century this was the premier copper mining camp in the British Empire, its total production amounting to some 20 mil- lion tons. Most of this ore came from the great Granby mines at Phoenix, but the Motherlode mine at Deadwood camp, 6 miles to the west, and several mines in Summit camp, 5 miles north of Phoenix, made important contributions. The large deposits were exhausted in 1918 and the district since has seen only desultory exploration and salvage operations. The orebodies are mineralized skarn zones in limestone members of a thick series of Upper Paleozoic sedimentary and volcanic strata. Chalcopyrite is the primary ore-mineral. Copper carbonates and silicates occur sparingly in outcrops, but the oxidized zone generally is very shallow. Much of the surface is mantled by glacial drift which in most places ranges in thickness from 2 to 15 ft. In some of the hanging valleys, however, the glacial drift may be as much as 100 ft thick and may assume drumlin-like forms.

Jan 1, 1954

By H. M. Chance

THE present value of most coal properties resides largely in the coal remaining to be mined, which thus constitutes the most important asset. The object of this paper is to discuss methods commonly used in computing the value of mineable coal. To distinguish clearly between such coal values and the values of other property, the several kinds of property values may be divided into classes; this is necessary to avoid unintentional omissions of items of importance. VALUE OF COAL RESERVES Judicial decisions prescribe, and appraisers commonly accept, current sales value as the preferred means for determining the value of transferable property. With few exceptions a property is worth the sum that can be realized from its sale by a willing seller to a willing buyer, a sale in which compulsion urges neither party, and between whom there is no community of interest to fix a value; or it is worth at least as much as a responsible buyer will offer for it. Actual sales of like property or bids from responsible buyers for the property, or for substantially like property, are the best established methods for determining values. Only in the absence of such sales or bids can valuations by other methods be entertained, and only for reasons of weight can sales values be set aside. Sales of coal in the ground, as customarily carried out through lease, under royalty agreements, are therefore the most trustworthy means available for determining the value of coal reserves.

Jan 6, 1926