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By J. Murray Riddell, Grover J. Holt, Arthur E. Anderson

Out of the depths of each business cycle we emerge with a stimulus for greater efficiency and a realization of progress in industrial technique. The recent years have not been an exception to this rule, and in retrospect we sense that significant advances have been made in mining practices on the Mesabi Range, with emphasis on speed of production and economy of operation. A survey of such changes does not reveal anything that is fundamentally or basically new, but it is apparent that ideas and machines that have found wide application in industry elsewhere, with necessary modifications, are being put to productive use in mining iron ore. Innovations in transporting and conveying ore from the open pits stand out with greatest prominence, so that, in the main, it will be with these features that this paper will treat, in the review of progress made to this date. The late years have witnessed the development of small deposits for open-pit operation, the cleaning up of pits nearing exhaustion, and in two large operations the approach to the limit for haulage by steam locomotives, owing to grades, making it necessary to recover the ore in slopes, track benches and below the power-shovel limit by a milling and scram operation. For several years small standard-type dump trucks have been used in clean-up or scram operations within the pits, but during the season of 1936 the first effort was made to use heavy truck haulage in the transportation of stripping and iron ore. The new units in use today vary from 15 to 20 tons in capacity, and are equipped with powerful gasoline or Diesel engines and supplemented by trailers or wagons on rubber or crawler treads. The Diesel engine finds favor with most operators because of fuel economy. These units develop upward of 125 hp. in the 15-ton trucks. The speed of these trucks varies from 2 miles per hour in Pow gear to 35 in high gear. The transmission affords 12 speeds forward and 3 speeds in reverse.

Jan 1, 1940

By J. Murray Riddell, Arthur E. Anderson, Grover J. Holt

Out of the depths of each business cycle we emerge with a stimulus for greater efficiency and a realization of progress in industrial technique. The recent years have not been an exception to this rule, and in retrospect we sense that significant advances have been made in mining practices on the Mesabi Range, with emphasis on speed of production and economy of operation. A survey of such changes does not reveal anything that is fundamentally or basically new, but it is apparent that ideas and machines that have found wide application in industry elsewhere, with necessary modifications, are being put to productive use in mining iron ore. Innovations in transporting and conveying ore from the open pits stand out with greatest prominence, so that, in the main, it will be with these features that this paper will treat, in the review of progress made to this date. The late years have witnessed the development of small deposits for open-pit operation, the cleaning up of pits nearing exhaustion, and in two large operations the approach to the limit for haulage by steam locomotives, owing to grades, making it necessary to recover the ore in slopes, track benches and below the power-shovel limit by a milling and scram operation. For several years small standard-type dump trucks have been used in clean-up or scram operations within the pits, but during the season of 1936 the first effort was made to use heavy truck haulage in the transportation of stripping and iron ore. The new units in use today vary from 15 to 20 tons in capacity, and are equipped with powerful gasoline or Diesel engines and supplemented by trailers or wagons on rubber or crawler treads. The Diesel engine finds favor with most operators because of fuel economy. These units develop upward of 125 hp. in the 15-ton trucks. The speed of these trucks varies from 2 miles per hour in Pow gear to 35 in high gear. The transmission affords 12 speeds forward and 3 speeds in reverse.

Jan 1, 1940

By T. H. Aldrich

THE Aldrich Mining Co. holds under lease from the Illinois Central R. R. Co. about 14,000 acres, in the East half of Township 12, Range 12 `V., in Marion county, Alabama, and owns other lands, of which about 1,000 acres adjoin this leased tract, making a total area of about 15,000 acres, all of which is underlain by the coal-seam upon which the company is operating. This seam is nearly horizontal ; and a ravine, diagonally crossing the tract, exposes the outcrop on either side for about 2 miles. The territory has been so divided that nearly the whole of it can be worked out by two collieries. The mines at Brilliant were opened in the Fall of 1898, and shipments began in the following spring. The original plan was to furnish steam-coal for locomotives to the Illinois Central R. R. Co.; and upon this expectation the investment of capital was made. The field was entirely new; and the softness of the coal at the outcrop induced the belief that it could be very cheaply mined. A contract for the delivery of a large quantity of coal to the railroad was accordingly executed. But with the advance of the entries to increasing distances from the outcrop, the coal proved so hard that it could no longer be drilled with a breast-auger; and the expense of mining became so great that the contract for cheap steam-coal had to be cancelled. It became evident that the work must be done with machinery and explosives, if it could be profitably done at all. On the other hand, the excellent quality of this coal opened, at the same time, a possible market not specially contemplated at the outset-namely, that of a first-rate coal for domestic and general uses. Since no other deposit of such coal was known to exist on the line of the Illinois Central, or any other railroad

Jul 1, 1906

By John Jermain Porter

(San Francisco Meeting, October, 1911.) THE value of any particular ore, coke, or limestone, for iron-making, depends upon its effect, first, upon the quality or value of the resultant product; and second, upon the cost of smelting. The factors under the first head are the percentages of phosphorus, manganese, and other elements, which remain in the pig-iron ; while those under the second head are the percentages of iron, carbon, or lime, the slag-forming constituents, which must be fluxed, and any other ingredients which give rise to variations in cost of fuel and flux. The first of these criteria of value is perhaps not capable of being reduced to a general formula embracing all cases, since it must vary to a great extent with market-fluctuations. For example, Bessemer pig is worth sometimes more and sometimes less than foundry-pig ; and the premium paid for high manganese varies within wide limits. The second, or smelting-value, however, can be expressed numerically with a fair degree of accuracy; and it is with this phase of valuation that the present paper is concerned. The utility of a means of comparing numerically the relative smelting-values of different ores, cokes, and limestones, is self-evident, although it may not have importance in Northern practice, where materials are largely standardized. On the other hand, there are, especially in the South, many furnace-managers who must use a great variety of materials of widely varying grade; and it is with special reference to this district, and in connection with the efficiency-methods which I have elsewhere proposed,1 that the methods herein described were devised.

Mar 1, 1912

By G. H. LeFevre

THE Metal Sales Department, with offices in New York, is responsible for the sale of the Company's products, with the exception of gold and coal. At present the department handles the sales of lead, zinc, silver, antimonial lead, , cadmium, bismuth, arsenic trioxide, and tellurium; gold is shipped direct to the United States Mint and coal is marketed by United States Fuel Company's own sales organization. The department keeps in close touch with the metal markets and collects information on marketing conditions, which it makes available to other departments of the Company. The electrolytic lead produced at the U. S. S. Lead Refinery, Inc., is a high-uality product marketed as corroding grade under the "U. S. S.-ELECTRO" brand. It is largely sold to manufacturers of paints, pigments, lead oxides, and storage batteries.

Jan 1, 1948

By Thomas T., Read

THROUGHOUT the Colonial era, Philadelphia was easily , the leading city of North America, and it still held that position at the end of the period, with a population of about 25,000, though closely pressed by Boston, which had slightly over 20,000, and New York, which had nearly as many. It was the center of a region in which mineral industry was important. Thomas Rutter's bloomery, built in the Schuylkill valley in 1716, was quickly followed by many others, and during the Colonial period at least 20 blast furnaces, 45 forges, and iron- works of other types were built in eastern Pennsylvania, which easily led all the other colonies in iron manufacture. During the Revolutionary period others were erected as far west as Fort Loudon, in the Cumberland c alley.^ After 1800 the rapid development of the anthracite mining industry profoundly affected Philadelphia's, development, since transportation of the coal was then necessarily by water, and the streams of the anthracite . regions mostly flowed into either the Schuylkill or the Delaware Rivers. With an abundant near-by supply of coal and iron, with the seat of government, which had been there since 1774, and with a National Bank established there in 1791, one would have seemed safe in prophesying, at the beginning of the nineteenth century, that Philadelphia would permanently remain the leading city of the United States. Education in Philadelphia was at first wholly in the hands of the Quakers, who had established a "Public School" there in 1689, but in November 1739 George Whitefield, who had created a sensation in England by his preaching, though only 24 years old, passed through Philadelphia on his way to Georgia to found an orphan school there. He preached a series of sermons in Christ Church that were so disturbing to the established church that on Nov. 25 the Rev..Richard Peters (who was also Provincial

Jan 1, 1941

By Ogden Tweto

The classes of ore deposits in the mountain province of Colorado that have been the most productive in the past and that offer the greatest promise for the future are: (1) disseminated or stockwork molybdenum deposits associated with Tertiary stocks; (2) combination precious- and base-metal veins in Tertiary volcanic rocks; and (3) base-metal replacement deposits and veins in Paleozoic sedimentary rocks. Veins in Precambrian rocks, including precious metal-bearing sulfide veins, gold-silver telluride veins, and tungsten veins, have been mined extensively in the past, but their aggregate output has been far subordinate to that of the groups named above, and the outlook for major output from them in the future is poor. Principal ore deposits of south-central Wyoming are sedimentary iron ores of Precambrian age and uranium deposits in Tertiary sedimentary rocks. Precambrian deposits of several kinds are scattered through the mountains of both states. The most promising of these, based on present indications, are vanadiferous titaniferous magnetite in southern Wyoming and southwestern Colorado and thorium-niobium rare-earth deposits associated with alkalic intrusive complexes in Colorado. Most of the mining districts of Colorado are in the Colorado mineral belt, a generally narrow but somewhat irregular belt that extends northeastward across the north-trending mountain ranges and the north-northwest trending geologic grain of the state. The belt is characterized by intrusive rocks of Laramide and younger age and by ore deposits, and it occupies environments ranging from Precambrian crystalline rocks through Paleozoic and Mesozoic sedimentary rocks to Tertiary volcanic rocks. Two ages of intrusion and ore deposition recently have been recognized in the mineral belt. One is Laramide (late Cretaceous and early Tertiary), and the other is Oligocene. As interpreted herein, the major replacement deposits and most of the sulfide vein deposits in Precambrian and sedimentary rocks are Laramide in age, and the molybdenum deposits, the tungsten and the gold telluride veins in Precambrian rocks, and the precious- and base-metal veins in volcanic rocks are Oligocene in age. In general, the Laramide deposits are mesothermal in aspect, and the Oligocene deposits are principally epithermal. The existence of two mineralization stages, in considerable part characterized by different suites of metals, has many applications in exploration.

Jan 1, 1968

By E. N. Harshman

Uranium mining and milling are rather new industries in Wyoming and South Dakota, but, in the past 15 years, ore valued at more than $400,000,000 has been mined and milled in the region. The major uranium deposits are in structural and/ or erosional basins or on the flanks of uplifts. The principal host rocks are medium- to coarse-grained sandstones that were deposited in continental or brackish-water environments and were derived in large part from the granitic cores of the uplifts and the sedimentary rocks that flank the cores. The ages of the host rocks range from Cretaceous to Miocene, but more than 95 per cent of the known reserves in the region are in rocks of early Eocene age. The bulk of the ore in the region is unoxidized and lies below the water table; some oxidized ore has been mined in the Powder River Basin and Black Hills districts. The unoxidized ore comprises pyrite, uraninite and/ or coffinite, marcasite, hematite, jordisite(?), and selenium. Minerals in the oxidized ore include hydrous uranium carbonates, phosphates, and sulfates and hydrous uranium and/ or vanadium silicates. The deposits are in the form of ore rolls that contain from a few hundred to a few hundred thousand tons of ore, ranging in grade from 0.1 per cent to 1.0 per cent U3O8. The rolls are at the margins of large tabular bodies of sandstone that has been altered by the orebearing solutions. The deposits are believed to have resulted from the interaction of an alkaline; oxidizing, ore-bearing ground water and a reducing environment. Exploration guides include the spatial relations of ore to altered sandstone, favorable lithology in the host rock, the content of certain elements and/ or compounds in ground water, and the relation of deposits to major paleodrainages.

Jan 1, 1968

By F. E. Bedale

STUDY of several severe mine explosions that occurred during the winter of 1907 led to the belief that coal dust was a definite explosion hazard. The Consolidation Coal Co. was a pioneer in the early work to' eliminate this hazard and to combat the dangers incident to poor ventilation and the presence of methane. Maintenance of high humidity throughout the mines was one of the first measures adopted, later to be superseded by rock-dusting. In the twenty years from 1907 on, many safety measures were developed and adopted, and several prizes were won, though the practice was crude by present-day standards. But in 1927, the company went to work in earnest, and organized a Department of Safety with adequate personnel and with authority to enforce all approved rules for the prevention of accidents and the preservation of company property. All plans for new construction work, changes in mining systems, and proposals for the purchase of new mining equipment had to receive the approval of this Department. A set of operating- and safety standards was written to govern the activities of all employees, and physical examinations for them were required.

Jan 1, 1938

By ERNEST A. HERSAY

ACCURATE ore-sizing with screens is drawing attention to certain details that now, more than ever before, require attention. There are many tests that must be preceded by careful sizing. The assayer often could profit by a more careful selection of screens. In milling, more attention is given the slimes produced. Cement-manufacturers are pulverizing and screening finer than they formerly did, and others are reducing materials to fine sizes at high cost, with screens used to govern the fine¬ness of the pulverized product. Fine screens are expensive, easily injured by mis-use, are carried in stock sparingly by most dealers, and are handled often by those who know little about them except their designated number. More attention, on the whole, needs be given the actual size of the mesh-openings, and less emphasis placed upon any custom or conventionality in numbering. An effort to classify wire screens, in this respect, leads at once into computations, where one is confronted with details of sizes and standards, of different wires, different gauges, and different customs. There is always uncertainty about the exact working-size of a screen until one gives the matter special attention, and devotes more time to it than its simplicity seems to demand. To know only the number is not sufficient for all uses. Often, in sets, superfluous sizes are used; and sizes are omitted that are of critical importance. In wire screens, the use of different standard sizes of wire makes important differences in dimensions that must be taken into account. The dealer usually grades screens by the number of openings per linear dimensions, regardless of the size of the openings or of the wire. Certain 100-mesh screens in use are found, by measurement, to he actually coarser than others of 90-mesh, a result which is due, of course, to the use of larger

May 1, 1906

By B. S. Butler

The principal ore deposits of Arizona are in the southern, cen-tral, and western portions of the state, which physiographically are part of the Basin and Range province, southwest of the Colo-rado Plateau (Pl. I). The Basin and Range province is characterized by numerous subparallel mountain ranges separated by plains or valleys. Most of these ranges trend northwest to north, parallel to the margin of the Colorado Plateau; but in southeastern Arizona, southern New Mexico, and northeastern Sonora, they trend northward, transverse too the edge of the Plateau. The mountains rise abruptly from plains or valleys, the margins of which in many places are pediments cut on hard rock. Some of the plains form closed basins (bolsons, playas), but most of them are drained. The Basin and Range province in Arizona is divisible into the Mountain Region and the Desert Region4 (Pls. I and II). The Mountain Region forms a belt 60 to 100 miles wide that contains most of the large ore deposits. Its longest range measures about 55 miles, the widest 20 miles, and the highest peak more than 10,000 feet above sea level or 7,000 feet above adjacent valleys or plains. Broad plain-forming valleys are exceptional, but several with maximum widths of 20 to more than 30 miles appear in the southeastern portion. In the Desert Region the mountains are relatively low, narrow, serrated, and steep, with sharply angular profiles. There are a few exceptionally large ranges of which the longest measures nearly 100 miles and the widest 18 miles. The highest peak is some 7,000 feet above sea level, and the maximum local relief amounts to about 5,400 feet. Broad and comparatively low desert plains form 50 to 75 per cent of the area.

Jan 1, 1939

Secretary of the Interior, Franklin K. Lane, has appointed a commission of five mining and metallurgical experts from the Bureau of Mines and the Geological Survey to visit Europe to observe and study reconstruction methods in the devastated regions of France and Belgium. The chairman of the commission is Dr. Frederick G. Cottrell, chief metallurgist of the Bureau of Mines. The other members are: George S. Rice, the chief mining engineer of the same bureau; Frank H. Probert, consulting engineer of the bureau, and. professor of mining in the University of California; F. J. Cameron, consulting chemist of the bureau and expert on potash matters; and Hoyt S. Gale, of the Geological Survey, another expert on potash.

Jan 4, 1919

By AIME AIME

Award of a Gold Medal : to the Institute. The Jury of Awards of the Jamestown Ter-Centennial Exposition has conferred a gold medal, the highest distinction within its power,. on the American Institute of Mining Engineers for the excellence of its publications during the past decade. ; A half-tone photographic reproduction of both sides of the medal is given in the accompanying illustration.

Jan 7, 1908

By R. V. Whetsel, Valentin R. Garfias

Mexican petroleum production for 1928 was approximately 50,000,-000 bbl., the lowest in 12 years, showing a decrease from 1927 of over 14,000,000 bbl. The steady downward trend for the past 7 years has allowed Russia to outrank Mexico by a wide margin for third position and if the expected decline continues during 1929 it should place Persia ahead of Mexico as fourth in rank. The year 1928 was characterized by a continuation of the reentrench-ment previously begun by the oil industry in Mexico in an attempt to adjust itself to the adverse conditions caused by the steady depletion of the fields, the rapidly increasing competition from Venezuela and the United States and the as yet unsettled petroleum legislation and taxation situation. With the exception of the Isthmus of Tehuantepee, drilling in proved fields was considerably curtailed and although the number of wildcats completed exceeded those of the previous year, no extensive drilling programs were undertaken. Practically without exception, the major companies reduced personnel and operations to a point where they could meet existing conditions and mark time while awaiting a more stable basis for the future testing of unexploited regions. Many terminal and transportation facilities were abandoned during the year. Development Only 371 wells were completed during 1928, as against 583 in the previous year and 808 during 1926, and although the percentage of producers in 1928 was 34 per cent., compared to 26 per cent. in 1927, the initial production of -wells was considerably lower than during the previous year, a great number of the wells showing salt water and becoming "strippers" from the time they started to flow. Development is summarized in Table 1. Drilling in the Northern fields did not prove any new pools of importance, the most successful wells being located in the old producing areas of Cacalilao, Panuco and Topila. (Fig. 1 Very few of the producers made more than 1000 bbl. daily, and a great many less than 300 bbl. a day.

Jan 1, 1929

Aase, Glenn D., (J'40) Jr. Met.. American Smelt. k Refin. Co., Selby, Calif. Abadie, Henry G., (J'43) Petr. Engr., Avenal, Calif. Abbott, Clarence E., (M'04) Civil Engr., V.P.. Tennessee Coal, Iron & R.R. Co., 1542 Brown Marx Bldg., Birmingham, Ala. Abel, Raymond L., (M'28) Chem. Engr., C.O., Pitts¬burgh Chem. Warfare Procurement Dist., American Bank Bldg., Pittsburgh. Pa. Abel, Walter D.. (M'32) Min. Engr., Supvr. Engr., R.F.C.Lee Angeles, Calif. Abele, Louis T., (M'31) Route No. 1, Adameville, Tenn. Abell, Leo M., (M'31) Mill Supt. & Met., Emperor Gold Min. Co. Ltd., Vatukoula, Fiji Is. Abernathy, G. E., (M'38) Geol., Kansas State Geol. Survey, Pittsburg, Kans. Abernathy, Jack H,, (M'40) Asst. Cenl. Supt. of Prod., Sunray Oil Co., 11th Floor, Philtower Bldg.. Tulsa 3. Okla. Abernethy, D. Carl, (M'44) Min. Engr. Rm. 3217, N. Int. Bldg., Washington, D. C.

Jan 1, 1944

By J. Mizrahi, A. M. Baniel, A. Mitzmager, S. Star

This article gives an account of the latest developments in the use of TBE for sink-float separation of silicate minerals. A number of minerals for which the process has been tested and found suitable are reviewed. Specific examples are discussed in relation to the particular problems of sink-float separation and recovery of TBE as compared with non-silicate minerals. The economic aspects are outlined. Silica and silicates comprise the most common and abundant group of minerals, and since they are present in variable amounts in most ores, they constitute an appropriate subject for the review and discussion of the recent developments in the use of TBE for mineral concentration. The silicates considered as a group have an extremely wide range of chemical and physical properties. Some of these properties, which are common to all minerals, are of importance to concentration by TBE and are discussed in some detail in this paper, as well as the development of methods and apparatus for concentration and recovery of TBE and several examples of concentration of silicates. PROPERTIES OF MINERALS WITH RESPECT TO CONCENTRATION BY TBE The properties considered as most important to concentration by TBE are specific gravity, structure, surface and shape. The specific gravity of a mineral is a fundamental property and is constant between very close limits for the same species of different sources if particles are pure and free from cavities or cracks. In many species, however, solid inclusions and changes in chemical composition due to replacement of elements cause variations in the specific gravity. The plagio-clase series of feldspars between albite and anorthite illustrate this point (specific gravity from 2.60 to 2.77). Fig. 1 shows the specific gravity distribution of some of the common silicate minerals.' The highest specific gravity is about 4.7 (zircon) and the lowest is 2.0 (sepiolite), with most of them ranging between 2.6 and 3.5. Although most of the silicates given in Fig. 1 are found as constituents of rocks, those generally considered as rock making minerals are comparatively few. They include quartz, feldspars, nephelite, sodalite, leucite, mica, pyroxenes, amphiboles, chrysolite, kaolin, talc and serpentine. These minerals may appear in igneous rocks as coarse crystals in granites, syenites and diorites or as very fine grained dispersions in basalt and felsite. When the latter rocks occur in an ore, their specific gravities depend on the minerals present and structure. The same is true for the sedimentary and metamorphic rocks (sandstones, shales, gneiss, slate, schists). A comparison of specific gravities for the minerals listed in Fig. 1 with that of TBE (see Table I) shows that the important rock-forming minerals, with the exception of pyroxenes, amphiboles and chrysolite (olivine), lie in the specific gravity range of less than 2.96 and can therefore be separated by TBE. The ore structure is important both in determining the apparent specific gravity and the efficiency of TBE recovery. The structure can be compact (as in

Jan 1, 1963

By D. S. Jacobus

COMPRESSED-air motors are specially desirable, if economically practicable, for underground haulage, because they require no fuel, involve no danger of fire, and not only avoid heating and fouling the atmosphere with smoke and combastion-gases, but by the emission of expanding fresh air, cool and improve it and aid ventilation. The highest developments in the use of compressed-air motors for locomotion are to be found, in the opinion of the writer, in the principles of the Mekarski car-motor as applied to street tramways, and it is thought that notes taken regarding this system, during a recent trip to Europe, where two plants are in successful operation, at Nantes and Vincennes respectively, will be interesting to mining engineers. The plant at Nantes operates a street-line 5.2 miles long, requiring about twenty motors; the one at Vincennes about 7 miles of road. Each car at Nantes carries its own motor. At Vincennes, however, the motor-car is arranged to tow a second car containing no motor. The road at Nantes is the older, having been in successful operation for ten years, during which time neither the American consul, Mr. Shackelford, who has resided at Nantes for about five years, nor the vice-consul, Mr. Bennett, who has been at Nantes ever since the road started, has ever seen anything go wrong with the motors. DESCRIPTION OF THE RAILROA at Nantes. Motor-Car.—Two small engines are connected' so as to rotate the front axle of the car, a reversing lever being used to alter the cut-

Jan 1, 1891

By Frances H. Clark

IN a concern with the varied interests of the Western Union Telegraph Co., where practically all types of metals, both ferrous and nonferrous, are utilized, many types of failures of materials occur. These have to do not only with outside plant construction, such as corrosion and fatigue of line wire and cable, but also with inside plant equipment operating at such high speeds that rapid deterioration of metal. parts due to fatigue and wear results. Both corrosion and fatigue affect the life of copper wire so its normal life in any particular locality is largely dependent on the atmospheric conditions. Tensions vary widely owing to changes in temperature and ice and wind loadings and the wire is Subject to a great range of vibration caused by wind gusts aril vibration front trains or other heavy vehicles transmitted through the earth. High frequency low-amplitude vibrations are sometimes audible as singing in the wire. The other extreme is the vertical slashing or dancing of the wire observed during severe storms where amplitudes of 9, ft. or more at low frequencies have been observed.

Jan 1, 1942

Separates of all the Technical Publications published in 1931 are available at Institute headquarters. All the papers are on file in public, university and technical libraries, and when so indicated in the list, may be found in the Transactions. Copies of these papers have been mailed to those members of the Institute who 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-Nonmetallic Minerals; I-Mining Geology; K-Mining Administration; L-Geophysical Prospecting. Other members may obtain copies by writing to the Secretary. Additional copies are sold at the rate of I cent per page; minimum charge, 25 cents. Metal Mining Tech-nical Publi- Title Author Meeting TRanb. cation Volume No. and Page* 411-A.43 Ventilation at the Portovelo Mines, J. P. Harmon New York. T31, 83 Ecuador (18) Feb., 1931 425-A.44 Use of Models for the Study of Mining P. B. Bucky New York, Problems (28) Feb., 1931 Milling and Concentration 375-B.32 Ball Mill Studies, I (53) A. W. Fahrenwald New York, H. E. Lee Feb.. 1931 401-B.33 Experimental Flotation of Oxidized H. S. Gieser New York. Silver Ores (9) Feb., 1931 410-B.34 Flotation of Minor Gold in Large-scale E. S. Leaver New York, Copper Concentrators (32) J. A. Woolf Feb., 1931 414-B.35 Effect of Particle Size on Flotation A. M. Gaudin New York, (23) J. 0. Groh Feb., 1931 H. B. Henderson 416-B.36 Ball Mill Studies, 11.—Thermal A. W. Fahrenwald New York. Determinations of Ball Mill Effi- G. W. Hammar Feb., 1931 ciency (13) H. E. Lee W. W. Staley Iron and Steel Division 38QC.59 Open-hearth Steel Process as a Prob- E. R. Jette New York, C31, 80, 111 Iem in Chemical Kinetics (34) Feb., 1931 381-C.60 Thermodynamic Study of the Phasial Yap, Chu-Phay New York. Equi1ibriain the System Iron-car- Feb., 1931 bon (26) 382-(3.61 Influence of Dissolved Carbide on the Yap, Chu-Phay New York, Equilibria of the System Iron-car- Feb., 1931 ban (19) 383-C.62 Research on Blast-furnace Slags. R. S. McCaffery New York, Three papers (88) Co-workers Feb., 1931 384-C.63 Statistical Analysis of Blast-furnace K. S. McCaffery New York, C31, 60, 70 Data (13) R. G. Stephenson Feb., 1931

Jan 1, 1931

By W. Joseph Schlitt, William D. Southard, Bruce P. Ream, Lawrence J. Haug

The operation of Kennecott's Bingham Canyon copper precipitation plant, one of the world's largest, is described. This description includes a brief historical review of precipitation at Bingham and the general layout and operation of the present cone cementation facility. Current practices are based on results of studies undertaken to define improvements needed in each unit operation. These improvements were required to meet changing plant conditions and were implemented primarily within the constraints of the existing facilities. Specific unit operations included were the cone precipitators, the cone discharge thickener, the cone effluent settling basins, and the plate and frame filter presses. As a result of these improvements, loss of precipitated copper decreased and the degree of precipitation increased, raising copper recovery by 9 t/d. At the same time, iron consumption was reduced by 22.5 t/d. Problems in drying the cement copper were also overcome so that a product containing 12 - 15% moisture could be consistently delivered for smelting.

Jan 6, 1979