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By T. Inoue, T. Imaizumi

A simulation model has been developed to find out the possibility of improving the industrial closed-circuit wet grinding operations. The model involves a continuous tumbling mill in combination with a hydrocyclone to recycle the oversize material back to the mill. The mill is described by the breakage, i.e. the selection and the distribution, functions, co-ordinated with the diffusional mixing along the axis. The cyclone classifier is characterized by the partition function with allowance for the non-selective separation of part of the feed material into the underflow. The computer program developed incorporates an interactive capability to modify the operating conditions of the system whenever needed. The results are analysed for the operational conditions characterizing the mill and the classifier. Besides the steady state conditions some observations are also made about the dynamic responses of the closed circuit grinding system.

Jan 1, 1980

By Lawrence Burkhart, S. B. Joo

Axially unsymmetric ordered circulation patterns on the surface of a hemispherical constant volume drop with forced Internal motion were considered as a manifestation of hydrodynamic instability, which was affected by internal flow as well as by the properties of the interface A simplified mathematical model was analyzed In order to study the mechanism of onset of interfacial circulation from a non-circulatory basic state. Values of the critical Reynolds numbers were obtained when the basic state became a fully developed rotational flow and the values changed for different interfacial properties. The work describes a heretofore unreported surface flow pattern on drop surfaces From a practical point of new, any motion in the interface of a droplet can have a significant effect of mass transfer rates in solvent extraction processes Although surface motion in droplets actual processing equipment is very complex, continued study of the fundamental nature of such phenomena should ultimately lead to more effective equipment design procedures.

Jan 1, 1981

(Under this heading will be published notes sent to the Secretary of the Institute by members or other persons. ) A member, technically educated, with 20 years' practical experience as engineer, assistant superintendent, superintendent, and manager of large mines and mills on construction and operation, also experience in mine examination, is open to engagement. Metallurgist of 18 years' experience in Mexico with large plants is open to engagement. Last position, superintendent of copper smelting works. Best line, copper and lead smelting, but also experienced in mine valuation and ore-treatment investigation work. Speaks Spanish. A member of the Institute and graduate mining engineer with 10 years' experience in the Lake Superior copper district, also practical experience, desires position as superintendent or manager. Member, graduate mining engineer, experienced in mine and mill work, geology and field work, one year in the hydrometallurgy of copper, is open for engagement Aug. 15. A member, at present in the Southwest., desires a position as assistant superintendent or assistant manager with a mining company operating in Washington or Alaska. Experienced assayer and engineer. A member, technical graduate, with nine years' mining experience as assayer, engineer, foreman, manager's assistant, and superintendent of large development and operating mining companies in the United States and Mexico, is open for engagement. A member, technical graduate, 33 years of age, 11 years' experience as chemist, metallurgist and superintendent of lixiviation plant and in charge of construction of cyanide mill, desires position as assistant superintendent or superintendent of mining or milling company in United States or Canada. Young man, technical graduate, two and a half years' experience in chemical laboratory, desires position as chemist.

Jan 9, 1913

By Bernard Moore

THE last few decades have witnessed the introduction of many new nonmetallic mineral products and changes in the use of many of those already well known. Among these is diatomite, formerly employed as a mild abrasive and, at one time, as the absorbent material in dynamite. Now nearly 100,000 tons a year are mined and milled into such things as filter aids, cement admixtures, insulants, fillers, absorbents, cosmetics, cleansers, etc. Pumice, commonly regarded as only an abrasive, is now also employed as an insulant, as light-weight aggregate and as a concrete admixture. With increasing use of insulants, light-weight aggregates, and acoustic stuccos and plasters in the building trades, both these mate-rials should find increased application. Very large deposits occur in eastern Oregon and have been studied by the U. S. Geological Survey in cooperation with the Oregon State Mining Board.

Jan 1, 1934

By Archer E. Wheeler, Milo W. Krejci

There are two general methods in use for the production of metallic copper from matte which are worthy of consideration : (1) the Welsh blister process, and (2) the converter process.' As practically all of the copper produced to-day is made in converters, we will give a brief outline of that process before proceeding with the special subject of this paper. Matte may be roughly defined as a mixture of the sulphides of copper, iron, nickel, silver, etc. In the converter process this is blown up to metallic copper in a modified type of Bessemer converter. The conversion of matte consists mainly in, (1) the removal of sulphur in the form of SO2, and (2) the slagging of the iron. With this brief statement we come to the two subdivisions of the process of converting mattes: Converting with acid linings. Converting with basic linings. Converting with Acid Lininys, This is carried out by lining the converter with siliceous rock or ore, which performs two functions: It protects the iron shell of the converter from the molten charge, and it furnishes the silica for combining with the iron as it is oxidized from the matte, to form a ferrous silicate. It follows from the second of these functions that this siliceous lining must be replaced from time to time, and in practice it has been necessary to reline converters every 8 to 40 hr., this time varying in different plants and even with different linings in the same plant, the life of a lining depending upon the grade of the matte treated, and upon the composition, the thickness, the tamping, and the drying of the lining.

Jan 1, 1914

By H. Landsberg

Biological as well as geological research has made very successful use of the qualities that the physicists have detected in radioactive substances. Outstanding examples for the vast new fields opened in this part of the border-land between the disciplines of geology and physics are the "radio thermal geology" [July, 1909, see 1 of "References" at end of paper] and all that is connected with the use of the radioactive disintegration clock for the age-determination of rocks and minerals [2]. In structural geology, not unlike to recent bi-ological uses of radioactive material, their "tracer" properties were helpful. Changes in Radon concentra-tion in soil-air, especially accumulations, led to hidden crevices and fault-zones. High contents of Radon in spring-water gave clues as to the types of rocks they had flowed through [3, 4). One specific application of the small admixtures of radioactive material, however, has only lately found some atten-tion and that is their use in linking beds of sedi-mentary strata otherwise only poorly identified be-cause of the lack of fossils or other characteristic properties. To be useful for this purpose, two con-ditions have to be fulfilled: (1) The amount of radioactive material per unit-weight of rock in a given horizon should be uniform over a large area; (2) this same amount should change fairly rapidly in the vertical succession of layers.

Jan 1, 1940

By Kenyon E. Richard, James H. Courtright

SILVER Bell is situated 35 airline miles northwest of Tucson, Ariz., in a small, rugged range rising above the extensive alluvial plains of this desert region. Its geographical relation to other porphyry copper deposits of the Southwest is shown on the inset map in the lower left corner of Fig. 1. The climate is semi-arid. Altitudes range within 2000 and 4000 ft. Opening of the Boot mine, later known as the Mammoth, in 1865 was the first event of note in the district's history. Oxidized copper ores containing minor silver-lead values were mined from replacement deposits in garnetized limestone and treated in local smelters. Copper production had approached 45 million pounds by 1909 when the disseminated copper possibilities in igneous rocks were recognized. Extensive churn drill exploration carried out during the next three years resulted in partial de- lineation of two copper sulphide deposits, the Oxide and El Tiro. Although the then submarginal tenor discouraged exploitation of these disseminated deposits, selective mining of orebodies in the sedimentary rocks continued intermittently until 1930, providing a production total of about 100 million pounds of copper.

Jan 11, 1954

The following outline has been prepared by request with the help of leading professors, business men, and social workers. It is arranged to cover 64 or preferably 96 class periods-four to eight month's work at the rate of two or three periods a week. More time would be desirable, but less time would be better than nothing. Certain topics must be omitted, especially if the assigned number of periods are lessened, where time is lacking. Many subjects are suggested in order to permit of choice and adaptation to local conditions; this is merely a suggestive outline. The course should be supplemented y engineering trips to study certain industrial conditions and the betterment work of selected companies-and social agencies. It should also be accompanied by brief surveys and practical service by students along the lines indicated. Reports and essays should be written. This is not a regular course in sociology and economics. It is a course in "human engineering" and should probably be directed by an engineering professor of large practical experience. Other members of the faculty, sociologists, economists, selected engineers, employers, labor leaders or others may be requested to lead certain periods, as desired. Care has been taken to avoid biased judgment in selection of topics and references.* * The authors of this outline have compiled an exhaustive list of references to books and periodicals relating to each group of topics. Lack of space prevents the publication of these lists in the BULLETIN, but they will gladly be supplied on request.-Ed.

Jan 12, 1917

By Harry M. Roeser

As a result of the publication, several years ago, of some articles on determining the constants of empirical formulas, the determining the constants of types of curves used for estimating the production decline of oil wells was brought to the writer for study. Methods requiring the minimum of time and labor and the maximum of rigor were sought, as it appeared that the nature of the data from which such curves are computed and the relative uncertainty of occurrence of the events predicted from them did not justify close adherence to the theory on which the solution of such problems is ordinarily based. The technical deficiencies of the solutions presented in this paper, from the standpoint of the method of least squares, are readily apparent to those familiar with that method, but their presentation in detail here is irrelevant to the subject matter. However, it is the author's conviction, after a rather exhaustive study of the problem, that the value of the solutions lose little by the approximate application of the conventional theory. It must be understood by those who use these formulas that the solutions herein given, and the formulas based on them, are merely facilities to aid the valuation engineer in forecasting future events. It is assumed, also, that before application is made of them, prescient judgment based on the circumstances in each case, shows that the forecast has some probability of realization. On this basis only will these formulas be found useful.

Jan 1, 1925

By Uros Bajzelj

To mine very weak carboniferous schists subjected to high ground pressures the underhand cut-and-fill stoping method was proposed using an artificial plate roof. An experimental stope was mined using three consecutive levels. Rock pressures, deformation of the reinforced concrete plate, and the quality of stowing were evaluated. It was found that roof deformations were minimized if the reinforced concrete plate and uncemented backfill were replaced with cemented backfill containing reinforcement near the bottom. The mining method prevented the occurrence of high rock pressures at the face. The method is suitable for mining subvertical ore bodies with large horizontal areas.

Jan 1, 1984

By John Fulton

The Connellsville coal-field is a separate strip of the upper coal measures, flanking the Chestnut Ridge along its western side. It extends from a point a few miles south of Uniontown, in Fayette County, following a northeasterly course parallel to the trend of Chestnut Ridge, through Fayette and Westmoreland counties, with its terminal prongs resting 011 the southern portion of Indiana County, north of the town of Blairsville. This belt of coking coal will average about three miles in width and over sixty miles in length, affording nearly, if not quite, two hundred square miles of this large coal-bed.

Jan 1, 1885

Jan 1, 1920

C. R. CORNING, Chairman. ADOLPHE E. BORIE, First Vice-Chairman. THOMAS T. READ, Secretary, Woolworth Bldg., New York, N. Y. Vie-Chairmen. JOHN H. ALLEN, GEORGE M. COLVOCORESSES, RICHARD M. ATWATER, JR., ROBERT PEELE, GEORGE D. BARRON, CHARLES P. PERIN, A. CHESTER BEATTY, JOSEPH A. VAN MATER, J. PARKE CHANNING, ARTHUR L. WALKER. D. C. Bard, Howard Eckfeldt. Philip N. Moore, W. de L. Benedict, R. C. Gemmell, T. H. O'Brien, John C. Branner, F. Louis Grammer, James J. Ormsbee. Palmer Carter, Ernest A. Hersam, Edward W. Parker, Allen J. Clark, Edwin C. Holden, John B. Porter, F. Crabtree, William L. Honnold, R. DI. Raymond, George G. Crawford, Reginald E. Hore, Robert H. Richards, O. C. Davidson, C. Colcock Jones, LeRoy Slash, E. V. D'Invilliers, Eugene P. Kennedy, Frederick H. Sexton, James S. Douglas, Chester F. Lee, Henry L. Smyth, Walter Douglas, Richard S. McCaffery, F. W. Traphagen, Howard N. Eavenson, James F. McClelland, Elton W. Walker. Milton H. McLean, The Chairman of the Committee on the eve of his departure frog -,he country for an extended stay, addressed the following letter t ,he President of the Institute NEW YORK, N. Y., APRIL 19, 1913.

Jan 5, 1913

By M. R. Geer, H. F. Yancey, P. S. Jacobsen

Two growing problems confront the preparation engineer-still further restrictions on stream pollution and a greater proportion of fine coal as more and more continuous miners come into use. The dewatering screens, centrifuges, and settling ponds that sufficed a few years ago must often be supplemented by more effective equipment, and in some instances the finest solids are now being recovered by vacuum filtration, once considered too costly in many coal washeries. Unfortunately not all slurries can be readily filtered. Some are virtually unfilterable, and others do not permit the high cake rates needed to hold costs within reason. Often, however, these difficult slurries can be rendered filterable by flocculation. Starch and lime have long increased settling rate in thickeners and can also aid filtration. More recently there have been other flocculants, primarily synthetic polymers or gums. Reports of their great effectiveness prompted the U. S. Bureau of Mines to test their use in filtration as part of its program on recovering and cleaning fine coal. The object of the present work was to compare some of the newer flocculants with starch and lime and to test the reaction of different types of slurries to flocculation. Three natural slurries, three synthetic coal-clay mixtures, and five flocculants were tested, all with a laboratory filter leaf.

Jan 7, 1959

By R. S. Shoemaker, F. W. McQuiston

BENGUET EXPLORATION, Inc. Tuba, Benguet, Philippines 1970 Operating Data ORE DESCRIPTION: Complex ore mostly sulfides and composed mainly of sphalerite and pyrite with minor amounts of chalcopyrite, galena, arsenopyrite, hematite, magnetite, chlorite, calcite, garnet and quartz. TYPE OF MINE: Underground, cut and fill method ORE HAULAGE TO MILL: Mine rail cars with electric locomotives. CAPACITY in TONS/24 HRS: 130 ASSAYS: Mill Heads Mill Tails Au = 0.65 oz per ton Au = 0.096 oz per ton Cu = 0.75% CU = 0.27 % Zn = 10.50 % Zn = 0.64 % Ag = 3.20 oz per ton Ag = 0.33 oz per ton Cd = 0.01 % PRODUCT: Au, Ag, Cu, Zn and Cd RECOVERIES: = 90% ~g = 89% Cu = 60% Zn = 94% SCREEN ANALYSIS OF MILL FEED: 90% -200 mesh POWER: Grinding 25.4 Kwh/T Copper Flotation 14.5 Zinc Flotation 13.3 Cyanidation 20.4 Others 25.0 TOTAL POWER: 98.6 KwH/T WATER: Pumped from riverside and underground 50 to 100 meters distance. Consumption of about 700 gallons per ton of new water.

Jan 1, 1975

By Y. M. Chang, C. H. Pitt

A jet slurry apparatus has been constructed to test corrosive/erosive wear properties of grinding ball metal. Plain high carbon steel heat treated to a hardness of about 60 Rc was used. Slurries of quartz and chalcopyrite ore concentrate were used as the jetting media. Weight loss due to pure corrosion was determined by the linear polarization technique. Weight loss due to pure erosion was determined by jetting while cathodically protecting the sample. By comparing the total weight loss with the sum of the weight losses from pure corrosion and pure erosion, it was found that there was a synergistic effect between corrosion and erosive wear. Corrosion rate, erosion rate, and total erosion/corrosion rate are given as a function of pH and mineral type.

Jan 1, 1986

NAME AND OBJECT. SEC. 1. This Institute is incorporated under the Membership Corporations law of the State of New York ; its corporate name is American Institute of Mining Engineers; and its objects are such as are stated in its Certificate of Incorporation. ARTICLE II. MEMBERS. SEC. 1. The membership of the Institute shall comprise four classes, namely 1. Members ; 2. Honorary Members ; 3. Associates ; 4. Junior Members. All members shall be equally entitled to the privileges of membership, except¬ing that Honorary Members, Junior Members, and Members and Associates whose residences shall be outside of the United States, Mexico, and Canada shall not be entitled to vote. Members and Associates residing within the United States of America, Mexico, and Canada, and not in arrears for dues, shall be entitled to vote in person at the meetings of the Institute, or, as hereinafter provided for, by letter ballot. SEC. 2. The following classes of persons shall be eligible for membership in the Institute, namely : as Members, all professional mining . engineers, geologists, metallurgists, or chemists, and all persons actively engaged in mining and metallurgical engineering, geology, or chemistry ; as Associates, all persons desirous of being connected with the Institute who in the opinion of the Board of Directors are suitable.

Jan 1, 1923

Members whose deaths were reported from Apr 9, 1921 to Apr 7, 1923 Elected Died 1876 ABADIE, E R. 1923 1906 ADAMS, ARTHUR K 1920 1902 AHLES, ROBERT L 1921 1876 Akerman, Richard 0000 1884 ALEXANDER, CURTIS 1921 1918 ALLEN, CARL A 1923 1880 ALMY, WILLIAM F 0000 1893 AMSDEN, 0. B 1923 1917 ARGALL, P. H 1922 1917 ARNOLD, E C 1921 1914 ASANO, K 1921 1920 AUGUSTINE, ALBERT BEARSS 1922 1906 BAIRD, GEORGE A 1921 1921 BALDWIN, GEORGE P 1922 1920 BASKERVILLE, CHARLES 1922 1915 BENSEL, J A 1922 1890 BENSON, A J 0000 1912 BEST, WILLIAM NEWTON 1922 1892 BILHARZ, OSCAR M 1923 1890 BLACKSTONE, RICHARD 1922 1921 BLOOM, GEORGE BARNETT 1921 1905 BOSTWICK, WILLIAM A 1922 1884 BRANNER, JOHN C 1922 1920 BRIDGE, SAMUEL D JR 1921 1893 BROWNE, ARTHUR, 1922 1871 BUCK, STUART M 1921 1897 BURGER, C C 1922 1882 BURT, CHARLES S 1921 1921 BUTZ, Louis N 1922 1917 CAMPBELL, DONALD G 1921 1915 CAPLES, JAMES WATTS 1919 1892 CARLETON, JAMES G 1922 1914 CARUTHERS, A WAYNE 1922 1911 CHASE, FRED M 1921 1892 CLEMENT, F H 1922 1922 COAN, WALTER ERLING 1923 1872 COGSWELL, WILLIAM B 1921 1881 COLVIN, VERPLANCK 1920 1882 COOLIDGE, WALTER G 1922 1907 CORKILL, FREDERICK 1922 1912 COX, Guy H 1922 1883 CUNNINGHAM, JAMES S 1921 1873 DAGGETT, ELLSWORTH 1923 1916 DAULTON, THEODORE M 1921 1888 DICKERMAN, ALTON L 1921 1902 DIEFFENBACH, H M 1921 1911 DUNSTAN, SIMON P 1920 1917 DYNAN, ALAN E 1922 1920 EASTWICK, THOMAS H A 1922 1876 EDWARDS, J WARNER 1921 1914 ELDER, ROBERT B 1923 1885 EMMONS, ARTHUR B 1922 1911 ENGEL, GEORGE W 1920 1887 FERNOW, B E 1923 1879 FIRMSTONE, H1922

Jan 1, 1923

Jan 12, 1951

By Frank Hall

THE needs of the World War showed the necessity of a metal stronger than cast iron which would supplement the supply of steel. So patriotic metallurgists were spurred to new efforts to improve the status of that half-breed of the metal world that had been, more or less erroneously, christened semisteel. As a result, it was developed that for certain purposes semisteel was superior to steel in the manufacture of shells. Steel, because of its greater strength and toughness, is able to carry a greater charge of explosive, weight for weight; consequently, a steel shell can be expected to cause greater destruction when used against fortifications or other inanimate objects, while semisteel, because of its comparative brittleness and its resulting greater fragmentation, is capable of inflicting more serious loss of life when used against opposing forces of men. Therefore, each has its proper place in the economy of war. For the present purpose, steel may be defined as a comparatively pure iron whose physical nature is modified by small amounts of carbon, silicon, sulfur, phosphorus, manganese, and possibly other rarer elements; while cast iron generally is limited to approximately 93 per cent. of iron, the remainder consisting of larger percentages of carbon, silicon, sulfur, phosphorus, and manganese. Semisteel may be defined as cast iron in which the carbon and silicon have been reduced to as low a point as is consistent with maintaining the nature of gray iron, and in which the remaining elements are manipulated so as to give the greatest strength.

Jan 1, 1920