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By Ralph Hayden

PAGE I. IntRoduction........239 II. Definition of Anaconda SLime....240 III. The Source of Slime......240 Remodeled Flow Sheet......240 Old Plow Sheet,.......242 IV. ConStitution of Slimes......243 Chemical........243 Physical.........243 V. The Slime Problem.......247 VI. THe Experimental Slime Plant....248 VII. Slime Thickeners. ETc .......249 Slime Ponds........249 Tanks.........249 Comparative Efficiency of Open and Baffle Tanks .260 Callow Tanks........252 Kuchs-Laist Centrifugal Separator....253 Garred Filter........256 Dorr Continuous Thickener.....256 VIII. Concentrators........257 Round Table........558 Peck Centrifugal Concentrator....259 Competitive Tests.......260 Twenty-Deck Round Table..... 260 Slime Feed Distributor......261 IX. ConcluSion.........262 I. Introduction. In the wet concentration of ores there is always a certain amount of very fine material with which to contend. and which invariably carries such quantities of value that the treatment of it is worth while. commercially. This fine material usually contains that portion of the ore which hinders the separation of the mineral values: namely. the colloidal material resulting from the decomposition of certain constituents of the ore. The object of this paper is to show what efforts have been made to solve the slime problem as it occurs in the concentrator of the Washoe

Jan 1, 1914

By J. C. Bayles

Jan 1, 1885

By G. F. Tagg

EARTH-REISTIVITY measurements are often of service in obtaining information regarding geological formations, particularly when applied to structural problems. In such problems the masses of the various bodies are large, and have a corresponding effect on the average resistivity of the soil. Much work has been done using such measurements, but in general the method of interpretation employed is empirical. Since certain simple cases can be investigated mathematically, it appears to be quite sound to endeavor to apply the mathematical solutions to the practical results, in order to deduce from the latter such unknown quantities as depth. This paper deals with such a method of interpretation for the simple case of a single horizontal stratum. SURFACE Of EARTH In the method described by FIG. 1.-WENNER'S METHOD OT MEASURING Wenner1 for measuring earth resis- EARTH RESISTIVITY. tivity, four stake electrodes are driven into the earth in a straight line as shown in Fig. 1. A current I amperes is passed between the two outer stakes and the potential difference . V volts between the two inner stakes is measured. Then if a is the electrode separation, the specific resistance of the soil, which is assumed to be homogeneous, is given by the formula

Jan 1, 1932

By A. J. Jacobs, J. W. Spretnak, R. Speiser

The activities of nickel in liquid iron-nickel solutions containing from 10 to 90 at. pct Ni were measured over the temperature range .1510° to 1600°C. A special function was devised whereby activities can be computed by a graphical integration using the results of chemical analyses on the vapor phase alone. The liquid solutions studied exhibit negative deviation from Raoult's law, but they approach ideality as the temperature is raised from 1510° to 1600°C. The maximum heat of solution is less than -8.0 kcal per mole. The entropy of solution is less than —2.5 kcal per mole deg at 1510°C, and changes negligibly as the temperature is raised. The liquid iron-nickel solutions do not follow regular solution behavior. THE activities of the components of a liquid alloy system can be determined in favorable cases from the partial pressure of the vapor in equilibrium with the liquid alloy.' Assuming that the vapor over the alloy behaves as an ideal gas, the activity of component i is given by the expression, Where the superscripts 1, v, and o signify the liquid, the vapor, and the pure component, respectively; the f's are the fugacities, and the P's, the pressures. The quantities Pi and Pi can be determined by the

Jan 1, 1960

By L. M. Johnson, C. G. Janes

INTRODUCTION In May, 1966, the General Services Administration (GSA) announced a program to encourage additional domestic production of copper in the interest of national security. Upon learning of the copper production expansion program, Duval Corporation entered into negotiations with GSA for development of the Sierrita copper-molybdenum property under the program. Agreements between the GSA and Duval Sierrita Corporation, a wholly owned subsidiary of Duval Corporation, were concluded in 1967, with the Sierrita Concentrator beginning operation in 1970 at a designed capacity of 72,000 STPD. Subsequent additions and modifications have expanded capacity to 90,000 STPD. This property, located approximately 20 miles south of Tucson, Arizona, represents an investment including working capital of about $200 million. These funds were provided from an $83 million loan from GSA, repayable in copper valued at 38 cents per pound, $48.75 million of bank loans subject to U. S. Government V-loan guarantees, and Company capital contributions. Current general operating statistics for the concentrator are listed below: [Ore Grade 0.32% Cu., 0.030"/. Mo. Daily Tons Milled 90,000 STPD Annual Copper Product ion 94,600 Tons Annual Molybdenum Production 15,000,000 Lbs. Annual Silver Production 1,135,000 Ounces]

Jan 1, 1976

By Irwin Roman

In a previous paper,l a method was suggested for determining the depth to a bed in the simple case of a uniform overlying layer of constant thickness. The main purpose of the present paper is to show how a slight modification of that method has been used to interpret specific data obtained in the upper peninsula of Michigan by the staff of the Depart- ment of Mathematics and Physics of the Michigan College of Mining and Technology. The method of Tagg2 has also been used on the same data, thus furnishing a comparison of the two methods, as well as a method of using the two methods jointly. The method of measuring the apparent resistivity is that suggested by Wenner,3 and illustrated in Fig. 1. A current I enters the earth at the positive pole C and leaves it at the negative pole D. The potential V of the high electrode A, with respect to the low electrode B is measured by suitable means. The separation of the collinear points in the order shown, DBA C, is I, the same for each interval. If the resistivity of the overburden is po, and that of the bed is pa, the apparent resistivity is given by

Jan 1, 1934

By William B Price, Ralph W. Bailey

Arsenic, antimony and phosphorus are now used in the brass industry as standard inhibitors in preventing dezincification in condenser tubes. This subject has been thoroughly covered by Barry,l who de- scribed the testing procedure by total immersion of suitable specimens in a I per cent cupric chloride solution at definite temperatures. Effects of dezincification were then determined by loss in tensile strength and elongation of the test specimens after definite periods of immersion. In the crystallography of the chemical elements as tabulated by William Hume-Rothery,2 phosphorus (metallic), arsenic, antimony and bismuth are placed in group V-B and the type of crystal lattice for arsenic, antimony and bismuth is given as rhombohedral. The Metals Handbook3 lists them as 'rhobomhedral hexagonal," with the additional notation that for arsenic this is the ordinary form at 20°C.; other modifications known or probable at other temperatures. In view of these statements and of the fact that phosphorus, arsenic and antimony are effective in increasing the resistance to dezincification, it was natural to assume that bismuth would act in the same manner. A series of tests was therefore carried out employing the methods described by Barry. Much to our surprise, bismuth did not inhibit dezincification, but rather seemed to accelerate it. Tensile-test speci-

Jan 1, 1942

By Ralph W. Bailey, William B. Price

Arsenic, antimony and phosphorus are now used in the brass industry as standard inhibitors in preventing dezincification in condenser tubes. This subject has been thoroughly covered by Barry,l who de- scribed the testing procedure by total immersion of suitable specimens in a I per cent cupric chloride solution at definite temperatures. Effects of dezincification were then determined by loss in tensile strength and elongation of the test specimens after definite periods of immersion. In the crystallography of the chemical elements as tabulated by William Hume-Rothery,2 phosphorus (metallic), arsenic, antimony and bismuth are placed in group V-B and the type of crystal lattice for arsenic, antimony and bismuth is given as rhombohedral. The Metals Handbook3 lists them as 'rhobomhedral hexagonal," with the additional notation that for arsenic this is the ordinary form at 20°C.; other modifications known or probable at other temperatures. In view of these statements and of the fact that phosphorus, arsenic and antimony are effective in increasing the resistance to dezincification, it was natural to assume that bismuth would act in the same manner. A series of tests was therefore carried out employing the methods described by Barry. Much to our surprise, bismuth did not inhibit dezincification, but rather seemed to accelerate it. Tensile-test speci-

Jan 1, 1942

COMMITTEE ON INCREASE OF. MEMBERSHIP. C. R. CORNING, Chairman. ADOLPHE E. BORIS, First Vice-Chairman. THOMAS T. READ, .Secretary, Woolworth Bldg., New York, N. Y. Vice-Chairmen. JOHN H. ALLEN, GEORGE M. COLVOCORESSES, RICHARD AL ATWATER, JR., ROBERT PEELS, 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. M. Raymond, George G. Crawford, Reginald E. Hore, Robert H. Richards, O. C. Davidson, C. Colcock Jones, LeRoy Salsich, 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, Meetings of this committee were held at the Institute headquarters on April 18, and May 2 and 15. It was resolved that meetings shall be held monthly on the third Friday of each month.

Jan 6, 1913

By R. B. Brinsmade

The following is an attempt to form a formula by which a mine can be quickly evaluated, aft,er all pertinent physical data have been collected from observations on the ground by a competent mining engineer. Assumptions. Let Q = price to be paid for the mining property. M = cost of developing the mining property to yield y tons of ore daily. P = cost of suitable plant to treat y tons of ore daily, p = value of said plant when the mine has been exhausted. C = total fixed capital investment. W = working capital investment. Then let C + W = total capital investment. y = required yield of ore daily in tons. Y = yield of ore yearly in tons, d = number of producing days per year, u = average operating profit per ton of ore. R = rate of interest to be earned on total investment of (C + W). r = rate of interest to be earned on sinking fund annuity. v = tons of positive ore available in mine. x = tons of probable ore available in mine, z = tons of possible ore available in mine, m = fractional factor to change probable to positive ore. n = fractional factor to change possible to positive ore. Q = tons of total ore available in mine. t = time in years to exhaust mine at rate Y.

Jan 1, 1909

By C. W. Crispell

The four nomograms presented in this article were designed to simplify and make more rapid the calculations connected with the compression and transmission of air. The formulae involved are rather complicated, but the graphic solutions are simple; their use requires an ability to follow explicit directions and to interpolate values on a logarithmic sca1e. † For the sake of convenience, the nomograms will be divided into two classes, and the purpose and accuracy of each will be discussed. Power foR CompREssion It is frequently desirable to determine the horsepower necessary to compress a given amount of free air from atmospheric pressure to a certain final pressure. The nomograms in Fig. 1 and 2 present a rapid method of calculating the horsepower required to compress 1 cu. ft. of free air per minute by single or two-stage compression. The general formula for the horsepower required to compress air adiabatically is: S X 144 PVn [(P')n-1/sn -1 (1) where: P = absolute atmospheric pressure at compressor, in pounds per square inch. P' = final absolute pressure of compressed air, -in pounds per square inch. V = volume of free air compressed per minute, in cubic feet. S = number of stages. n = exponent of the compression curve.

Jan 1, 1918

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 Keith Sutherland

AEROFLOAT 25 is a complex mixture of free cresylic acid with aryl substituted dithiophosphoric acids, sulphides, disulphides, etc. Its complete composition has not been published by the makers or patentees. It is prepared1 by the reaction between phosphorus pentasulphide and carefully selected cresylic acid. We have been informed that this acid contains no phenol and very little cresol, and that it is rich in the higher alkyl phenols, particularly the xylenols. The reaction between a phenol ROH and phosphorus pentasulphide may produce compounds of the following type:2 (i) RO S P Diaryldithiophosphoric acids RO SH (ii) R-SH Thiophenolic compounds (iii) R-S-R Diaryl sulphides (iv) R-S-S-R Diaryl disulphides (v) Substituted thianthren compounds Except for the simplest type, the thiophenols (ii), the boiling points of these compounds lie above 300° C. The amounts of the thianthren compounds formed from the five xylenols (if all these are present) will vary according to the position of the substituents. In an attempt to ascertain something of the nature of the reagent, fractional distillation under atmospheric pressure was undertaken. At the outset, hydrogen sulphide was freely evolved, and-particularly below 200° C.-the fractions had the strong odor characteristic of the

Jan 1, 1939

By R. H. Moore

The data for diffusion in dilute binary alloys with the Solvents Ag, Cu, Ni, Fe. Al. and Pb hare been correlated as a function of atomic volume. Linear equations of the form: Q = b - a log V are obtained with constants "a" and "b" ciuirac-teristic of each solvent metal. In most cases. 3-d In recent years measurements of diffusion coefficients in solid binary alloys. using small concentrations of radioactive isotopes. have resulted in accumulation of highly reproducible data. Such and 4-d transition elements correlate on separate straight lines from those which serve to correlate the non/ransition elements. The data for the uon-transilion elements diffusing in silver and copper liave been fitted by least-squares analysis. It is concluded that the size and charge effects which determine the magnitude of the activation energy for diffusion are a function of atomic volume. systems represent the simplest possible examples of chemical diffusion since solute interaction effects can be neglected and Kirkendall-like phenomena do not occur. Generally it is found that thc diffusion rate of the solute is within an order of magnitude of the diffusion rate of the solvent. The differences have been attributed to the effect of size and to electrostatic interactions between the solute and solvent atoms.

Jan 1, 1965

By Ralph W. Bailey, William B. Price

ARSENIC, antimony and phosphorus are now used in the brass industry as standard inhibitors in preventing dezincification in [ ] condenser tubes. This subject has been thoroughly covered by Barry,1 who described the testing procedure by total immersion of suitable specimens in a I per cent cupric chloride solution at definite temperatures. Effects of dezincification were then determined by loss in tensile strength and elongation of the test specimens after definite periods of immersion. In the crystallography of the chemical elements as tabulated by William Hume-Rothery,2 phosphorus (metallic), arsenic, antimony and bismuth are placed in group V-B and the type of crystal lattice for arsenic, antimony and bismuth is given as rhombohedral. The Metals Handbook3 [ ] lists them as "rhombohedral hexagonal," with the additional notation that for arsenic this is the ordinary form at 20°C.; other modifications known or probable at other temperatures. In view of these statements and of the fact that phosphorus, arsenic and antimony are effective in increasing the resistance to dezincification, it was natural to assume that bismuth would act in the same manner. A series of tests was therefore carried out employing the methods described by Barry. Much to our surprise, bismuth did not inhibit dezincification, but rather seemed to accelerate it. Tensile-test speci-

Jan 1, 1942

By John V. Beall

What progress has been made in rapid excavation of tunnels and shafts? Where do we go from here? To get some answers to these questions was the reason that 500 tunnel men-contractors, geologists, professors, lawyers, mining engineers--came to the University of Minnesota May 15-17. The attendance of 500 astonished conference organizer Professor D. H. Yardley, who had anticipated half that number. They came from Japan, South Africa, Austria, Sweden, and Australia to name a few, and an officer of the Corps of Engineers thought all his people should have been there. The Civil and Mining Engineering Departments of the University combined for the program, which was staged by M. K. Cragun for the General Extension Division. The Saga of the Oso Tunnel The present state of the art of rapid excavation is "good." There is little controversy about where we go from here and what's more, this reporter finds that the technical know-how to automate excavation in any kind of ground is extant, even if it will take some years to achieve this state. In a nut- shell though, the present status can be seen in its various ramifications in the saga of the Oso Tunnel, as told by V. L. "Vic" Stevens of Boyles Brothers Drilling Co. :

Jan 7, 1968

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who called at Institute headquarters during the period Apr. 10, 1916; to May 10, 1916: Philip P. Baily, New York, N. Y. George W. Otterson Seattle, Wash. John M. Brooks, Jr., Knoxville, Tenn. C. Q. Payne, New York, N. Y. C. A. Burdick, New York, N. Y. Charles F. Potter, Los Angeles, Cal. W. N. Crafts, Oberlin, Ohio. Albert E. Rhoads, Harrisburg, Pa. Andrew B. Crichton, Johnstown, Pa. M. F. Sayre, Schenectady, N. Y. 0. P. Hood, Pittsburgh, Pa. H. V. Smythe, Northpines, Ont., Canada. W. McA. Johnson, Tulsa Okla. W. 0. Snelling, Long Island City, N. Y. G. H. Morgan, New York, N. Y. W. H. Staver, Ophir, Colo. E. G. Norton, Chicago Ill., A. W. Tucker, Salisbury, N. C. M. L. O'Neale, Coal City, Ala. Andrew Weisenburg, Philadelphia, Pa. Arthur H. Brown has resigned his position with the Dome Lake Mining & Milling Co., South Porcupine, Ont., Canada. Robert Sterling has resigned his position as chief engineer of the Goldfield Consolidated Mines Co., Goldfield, Nev., to accept the position of assistant manager of the vanadium mines of the Primos Chemical Co., Vanadium, Colo.

Jan 6, 1916

CHICAGO SECTION CHARLES H. MACDOWELL, Chairman, Luther V. DICE, Vice-Chairman, HENRY WT. NICHOLS,. Secretary-Treasurer, 164.5 E. 68 St., Chicago; Ill. ALEXANDER K. HAMILTON-, HENRY P. HOWLAND, GEORGE P. HULST, FREDERICK 1. SNYDER. There were 32 members present at the dinner of the Chicago Section which was held at the Chicago Engineers' Club on Friday Evening, December 22. At the meeting after the dinner, the Chairman called attention to the work of Mr. Hoover in Belgium and spoke briefly of the assistance which' could be given him through the Belgian Kiddies, Ltd. Mr. Alonzo Kinyon read a paper on "Burring Powdered Coal" which so interested the members that many of them participated in the long discussion which followed. Prof. Harry B. Pulsifier then described the metallurgical plants about Chicago. He mentioned briefly the equipment and interesting features of 30 metallurgical plants of importance and stated that there were also 200 foundries in the district. He said that when number, size, quality and diversity of the plants are considered, the Chicago District is justified in calling itself the greatest metallurgical center on earth. The paper was followed by a brief discussion in Which attention was called to some smaller and incipient plants of an interesting character. HENRY T. NICHOLS, Secretary.

Jan 2, 1917

By C. W. Crispell

THE four nomograms presented in this article were designed to simplify and make more, rapid the calculations connected with the compression and transmission of air. The formulae involved are rather complicated, but the graphic solutions are simple; their use requires an ability to follow explicit directions and to interpolate values on a logarithmic scale. ? For the sake of convenience, the nomograms will be divided into two classes, and the purpose and accuracy of each will be discussed. Compression It is frequently desirable to determine the horsepower necessary to compress a given amount of free air from atmospheric pressure to a certain final pressure. The nomograms in Figs. 1 and 2 present a rapid method of calculating the horsepower required to compress 1 cu. ft. of free air per minute by single or two-stage compression. The general formula for the horsepower required to compress air adiabatically is: HP = S X 144/33,000 PVn/(n-1) [(P'/P) n-1/Sn -1] (1) where: P = absolute atmospheric pressure at compressor, in pounds per square inch. P' = final absolute pressure of compressed air, in pounds per square inch. V = volume of free air compressed per minute, in cubic feet. S = number of stages. n = exponent of the compression curve.

Jan 6, 1917

By R. K. Adams

The availability of digital computers costing less than $15, 000 makes them economically attractive as versatile research and experiment tools. Several such installations at Oak Ridge National Laboratory have shown that improvements in research productivity and experimental control accuracy can result from the proper application of a small digital computer. However, careful attention must be paid to several potentially expensive problems in 1) interfacing the experiment to the computer and 2) programming the computer. Two specific applications of very small computers to metallurgical testing and research are described. One is a system for data acquisition and precise temperature control associated with a thermocouple testing program, and the other is a system for pulse calorimetry determination of the specific heat of metals over wide temperature ranges and in the neighborhood of metallurgical transformations. The data acquisition system which uses a PDP-8/S computer monitors signals from up to 264 low-level thermocouple signals at two scanning speeds: 10 readings per second for long-term drift data, and 500 readings per second for transient data. The pulse calorimetry system which uses a PDP-8 computer accepts up to 6 signals of 0- to 10-v range and because of a larger analysis program, uses a bulk memory (magnetic disc) in addition to core memory.

Jan 1, 1969