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US 4,192,852-Precipitation of iron values as a jarosite from a sulfate solution obtained as a byproduct in the hydrometallurgical processing of zinc sulfide ore The solution is cooled, partially neutralized, and clarified. The clarified solution is heated to a temperature of 80 to 100°C in the presence of sodium, potassium, or ammonium ions to precipitate substantially all of the ferric iron as jarosite The precipitate is thickened, filtered, and washed The residual solution may be processed for zinc or other nonferrous metal values R V. Pammenter and C J Haigh, assigned to Electrolytic Zinc Co of Australasia Ltd. Mar. 11, 1980. 16 pp. (423-42) Filed: 5-8-78 (903,524). Priority- Australia, 5-9-77 (PD0030) (Drawings below.)

Jan 1, 1982

By E. P. Mathewson

DURING the past 35 years it has been my privilege to deal with hundreds of recent graduates from engineering schools all over the world. In consequence, I, feel that I have learned something about the training of, engineering students. In the first place, I believe that too great specializa-tion is a mistake. A student should receive general training in engineering for at least three out of the four years of the course, and any specializing that may be required should come in the fourth year. Too great emphasis can not be laid upon the fact that the four years' training does not make an engineer; on the contrary, the graduate is only fitted to enter the pro-fession. He becomes an engineer in the true sense of the word only after years of practice; the college train-ing merely shows him where to look for information and develops his intellectual powers. Some of our engineering schools have lengthened the term of study to five years and talk of increasing it still further. This, in my opinion, is a mistake. A young man who spends more than four years in college is apt to become too academic and theoretical. It is better to stiffen the matriculation examinations than to prolong the years of study in college. No matter how good the faculty may be and how carefully selected the course of study, the graduate can never become an engineer unless he has some natural qualifications for the vocation. There are one or two subjects in which most recent graduates seem to be weak; these are accounting, the command of English, and training in the writing of reports. A short course in general accounting should always be included in the curriculum. To this should be added instruction in the preparation of estimates and cost statements. In making reports it should be borne in mind that these reports are to be submitted to busy men,-and not to technical men. The busy man wants the gist of the report summarized on the front page of the report. He wants to know that if he expends a certain sum of money in a certain way, he will get certain results and make so much profit. This should be put clearly before him in short statements, free from technical terms. The details of the report can follow .at greater length; it should be remembered that the employer is not going to read these details, but will confine his attention to the summary.

Jan 1, 1923

Edwin A. SpeRry, Denver, Colo. (communication to the Secretary*) :—Since writing my former paper on this subject I have had several discussions concerning some of the statements contained therein, with men who have had a large experience with the old form of buddle, both in this country and in Cornwall. The present paper gives a brief statement of some of the points debated, together with the arguments and proofs in their substantiation. The first point is the question of the capacity. In my origi-

Jan 1, 1904

By R. W. Raymond

I HAVE the pleasure of exhibiting samples of the rock in which the South African diamonds are said to occur, for which I am in debted to Mr. Franz Groeger, of Vienna, formerly an assistant of the Royal Imperial Geological Institution, whose account of the general geology of Southern Africa was contained in a recent number of the proceedings of that Institution. The rock is apparently a sort of tufa, evidently of volcanic origin. Mr. Groeger assured me that it could be seen in situ, bounded by uplifted stratified rocks; and that diamonds had been mined from it, by means of shafts, some distance below the surface. Groeger calls it "greenstone-tufa," and says of it, in the proceedings of the Geological Institution, " it breaks through the younger members of Group III [lower Trias and Jura], . . .. and crops out in oval masses, filling fissures . . ..The occurrence of this tufa is not locally limited, but has been traced and proved already over a large territory." DR. HUNT remarked that the material looked like the trass of the Rhine region. He thought it a new occurrence for diamonds. He believed diamonds to belong to ancient crystalline rocks, although these materials might be brought tip by volcanic agency, and the diamonds remain unaltered. In the volcanic rocks of Auvergne, crystals of sapphire, zircon, and spinel are found; and yet no one supposes that these minerals have been generated by volcanic agency. He had had a conversation with Bertrand de Lom on this subject, who agreed with him that these minerals, being hard and resistant,

Jan 1, 1874

Apr. 26-May 11, Liege International Fair, Liege, Belgium. May 4-8, Electrochemical Society, Inc., Spring meeting, Benjamin Franklin Hotel, Philadelphia. May 5-6, National Air Pollution Symposium, Huntington Hotel, Pasadena. May 5-7, American. Mining Congress, coal convention, Netherland Plaza Hotel, Cincinnati. May 6-9, Scientific Apparatus Makers Assn., annual meeting, Edgewater Beach Hotel, Chicago. May 9-10, AIME, joint meeting, Industrial Minerals Div. and Metals Branch, Davenport Hotel, Spokane, Wash. May 11-14, American Institute of Chemical Engineers, Atlanta Biltmore Hotel, Atlanta. May 17, AIME, Chicago Section, President's night dinner dance, Shoreland Hotel, Chicago. May 27, AIME, Morenci Subsection, Longfellow Inn, Morenci, Ariz. June 2-4, Chemical Institute of Canada, annual conference, Montreal. June 4-14, Mechanical Handling Exhibition and Convention, Olympia, London.

Jan 1, 1952

Discussion of the paper of J. V. EMMONS, presented at the Pittsburgh meeting, October, 1914. and printed in Bulletin No. 93, September, 1914, pp. 2233 to 2248. ALBERT SAUVEUR, Cambridge, Mass.-Mr. Emmons is to be congratulated for having placed before us in so forcible and satisfactory a manner a question of much importance-that of the surface decarbonization of steel. Of course, both manufacturers and consumers have known for many years that during the heat treatment of high-carbon steel, surface deca.rbonization is always likely to occur to a greater or less degree, but the subject does not seem to have been investigated with the method and thoroughness it deserves. I am in substantial agreement with Mr. Emmons's conclusions, and I have but little to add to what he has so well said. His statement that carbon dioxide is just as effective an oxidizing agent as pure oxygen is likely to cause surprise and some will wonder whether his investigation has been carried far enough to warrant so unexpected a conclusion. The reaction C + 0 = CO, expressing the oxidation of carbon by pure oxygen, is decidedly exothermic, whereas the reaction C + C02 = 2C0, expressing the oxidation of carbon by carbon dioxide, is endothermic. Decarburization by pure oxygen, therefore, should take place much more readily than by carbon dioxide. One cannot help regretting that the author does not mention' the best way of preventing in a practical manner surface decarbonization while treating tool steel and other high-carbon steels.

Jan 4, 1915

By James S. Foster, Paul G. Shewmon, Frank V. Nolfi

Analytical expressions are developed for the kinetics of dissolution or growth of a spheroidized, solute rich stoichiometric Precipitate in the surrounding matrix. There are two limiting cases; in one the rate of dissolution or growth is limited by long range solute diffusion through the matrix and in the other by the transfer of atoms across the mrdrix-precipitate interface. In the former case local interfacial equilibrium exists while in the latter it does not and the rate of dissolution or growth is controlled by an interfacial reaction. The analysis treats both limiting cases as well as mixed control in a single development, where it is found that the thermodynamic state of the interface is completely specified by a single parameter, o, defined by where K is the reaction rate constant, D is the matrix solute diffusivity, and R, is the precipitate radiz~s. If K is infinite then a is zero and local equilibrium prevails; if K deviates infinitesimally from zero, then a is very near unity and an interfacial reaction is rate controlling. Mixed control occurs for intermediate values of o. From the analytical results, numbers are computed which are useful in determining the duration of interfacial reaction or mixed control; following this time period, long range diffusion is rate controlling. THE rate controlling process or processes governing phase boundary migration has been the subject of much speculation and investigation. Traditionally, the most widely assumed boundary condition in quantitative treatments of this problem has been that of local interfacial equilibrium. This condition implies that long range diffusion of one or more elements controls the migration and is referred to as "diffusion controlled migration" (herein DCM). In contrast to the above view is the proposition that local interfacial equilibrium does not exist and that transport of atoms across the interface is rate controlling. Consequently, this mechanism is referred to as "interface controlled migration" (herein ICM). In processes of the latter type, the activity, a, of one or more elements is discontinuous at the phase bound- ary and the flux, J, across the boundary of a given element is some function of its activity discontinuity, a. One of the most comprehensive contributions to a mathematical description of phase boundary migration is due to am.' His analyses are applicable to precipitation in binary systems in which a) the precipitates are spherical* solute rich compounds of constant

Jan 1, 1970

[RALPH ADAIR Ore Dressing Consultant Bull Mtn. Rd., Asheville, N. C. Phone 4-1893 JAMES A. BARR Consulting Engineer Mt. Pleasant, Tennessee Washington, D.C. BEHRE DOLBEAR & COMPANY Consulting Mining Engineers and Geologists 11 Broadway New York 4, N. Y. I. R. BERENT Engineering Consultants and Contractors Mineral Exploration, Mine Evaluation, Mine Designs and Mine Management ` 188, Ataturk Bulvari-Ankara, Turkey BLANDFORD C. BURGESS Registered Professional Engineer Mining Consultant Monticello, Georgia GLENVILLE A. COLLINS Mining Engineer Uranium examinations Cable "Coins" 8 Haward-Canfleld Bldg. Santa Barbara, Calif.]

Jan 1, 1952

By Victor deWolfe

INTRODUCTION The Henderson Mine, located near Empire, Colorado, utilizes a continuous panel caving system to extract ore as one of the world's major producers of molybdenum. Any mine using a caving-by-gravity technique of mining must rely on closely controlled draw of the caved ore. This control is essential to insure proper caving action, to avoid damaging load concentrations of weight and to minimize the dilution of ore with waste material. Henderson is no exception. Draw control is a major factor in all production planning, from long- range plans to short-range and day-to-day ore scheduling. Draw control is reviewed constantly and administered daily in an effort to optimize production efficiency, ore recovery, and cave management. MINING METHOD The cave at Henderson is massive, moving slowly through large panels that are 244 m (800 ft.) wide by 610 m (2,000 ft.) long. Generally two cave areas are drawn at one time. The areas under active draw vary in size but can be as large as 244 m (800 ft.) by 244 m (800 ft. ) containing 400 draw points. Each draw point contains 45,360 mt (50,000 st) on the average and takes about two and one half years to exhaust. A complete panel is worked for seven to ten years. No pillar exists between panels, but rather a buffer zone of broken ore, or "static face," is left in each panel to be drawn with the adjacent, yet-to-be-caved panel in efforts of minimizing dilution of a working area from an exhausted one. (Figure 1) Production drifts are driven on 24.4 m (80 ft.) centers through the ore body. Between the production drifts are funnel-shaped draw bells on 12.2 m (40 ft.) x 24.4 m (80 ft.) centers to receive ore from the cave. Each bell is accessed by two draw points, one from the production drift on either side, thus forming a 12.2 m (40 ft.) x 12.2 m (40 ft.) draw pattern. Extraction of the ore is by rubber-tired, 3.8 m3 (5 yd3) load-haul-dump equipment. The LHDs then tram the ore a maximum of 49 m (160 ft.) to ore passes. Cave initiation and bell development are done from the undercut drifts which are parallel to and 17 m (55 ft.) directly above the production drifts. Longhole rings are drilled and blasted from the undercut drifts to define the bells and establish the undercut for caving. (Figure 2) DRAW CONTROL Since the cave line at Henderson is constantly advancing, it is necessary to be continually initiating new cave at one end while exhausting it at the opposite end. There must exist, therefore, an angle on the ore-waste contact in the broken rock from initiation to exhaustion. The basic concept of draw control is to keep this angle as smooth and even as possible, particularly at the time of exhaustion. If this is achieved, draw points are exhausted more or less in a line, avoiding pockets of remaining ore surrounded by exhausted areas. These pockets would cause spotty ore extraction at the time of exhaustion, increasing the amount of dilution occurring while introducing the potential for significant weight problems in the production area. To arrive at the desired angle on the ore- waste contact, maximum tonnage percentages are assigned to each row of draw points increasing at 10% or 15% increments (depending on cave size and velocity of draw) working away from the cave line. The available tonnage indicated by these percentages is the maximum allowable tonnage to be extracted from each draw point until the available tonnage percent- age is increased. As the cave moves, these percentages increase for each draw point regularly. However, in general the tonnage drawn from each draw point is kept at about 50% of this allowable maximum in order to maintain adequate available tonnage in the cave to sustain production for seven months if cave initiation were to cease. This available tonnage cushion is a safeguard built into the draw control program at Henderson to accommodate fluctuations in the rate of cave advance. When draw points move past the row of 100% tonnage availability, they are drawn past the desired 50% at the same increments per row until exhausted. (Figure 3) To achieve proper draw control, the number of LHD buckets to be taken from each draw point is assigned daily. The actual buckets taken, which may at times deviate from the

Jan 1, 1981

By G. E. Karantzavelos

Anew flotation process to recover alunite from low-grade alunite ores is described. The process begins with run-of-mine ore, reduced to less than 5 mm (0.2 in.), being preconditioned with the reagents before grinding and alunite flotation. From the preconditioning step, ore particles, impregnated with reagents, form pellets that subsequently disintegrate into the pulp during grinding. The second step is basically a standard alunite flotation step. Pilot plant test results show that an alunite concentrate assaying at least 85% alunite and less than 5% silica can be produced. Laboratory and pilot plant results were in excellent agreement, indicating that the new process is a viable means of alunite beneficiation. Plant results, using the new process, were superior to results from conventional alunite flotation procedure.

Jan 1, 1986

In their presentations Dr. Puddington and Dr. Stratton-Crawley have concentrated on spherical agglomeration and two-liquid extraction respectively. I should like here to complete the picture by putting these two techniques together in context with other techniques in which non-polar oils are used in the concentration and separation of minerals. Although these techniques are invariably treated separately and have been studied in isolation, there is a lot to be said for considering them together and trying to systematize their similarities and differences. This I take as a principle guideline in my introduction to this discussion. Four processes can be distinguished on the basis of the dosage of oil required: --simple flotation with collector-extender --agglomeration (emulsion) flotation --spherical agglomeration --two-liquid separation Dr. Stratton-Crawley has suggested that "pigment flushing" could find application in the treatment of ores. This is an interesting suggestion. However, the process can be regarded as a variant of two-liquid extraction, and it is convenient for me to do so in this discussion. Table 1 sets out some main features of these techniques. The first, in which the oil is used to enhance the strength and reduce the dosage of the collector is not designed for and has no special advantages in the treatment of fines, and therefore will not be further treated here. To add to the details appearing in the Table, thumbnail sketches of the other three, which all do show particular efficacy in the treatment of fine particles, are given below.

Jan 1, 1979

I TOLD you above that you should save the melted material that you extracted by smelting the ore. In substance this is copper, lead, silver, and perhaps gold, but all are like substances mixed in one body without any distinction. Now if you wish to separate these and to reduce them to their pure qualities, it is necessary to proceed with each one according to its own methods. Now in this method of separating lead in order to extract the silver and gold from the copper, it is necessary to return to the smelting and to follow one of two methods.* The first is to smelt it again with the addition of lead or lead ore, and to make it all run through the channel into the large forehearth that was made in front of the blast furnace, and, as it cools off, proceed to remove layer by layer with the fork, as I told you before and as you did the first time, until the work lead is reached. Then you assay what you have extracted and see whether it contains silver. If you consider that it has enough per hundred to justify the expense, return it again to the smelting. Continue to do this until you have extracted all the unctuousness and the work lead still remains. If it contains little or no silver, you must be satisfied with your work; otherwise return it again to smelt, always accompanying it with lead or galena and do as you did the other times until it

Jan 1, 1942

By W. J. West, T. D. Mueller, J. E. Warren

The authors have presented valuable information on the influence of the interfacial tension and the contact angle on the recovery efficiency of the waterdrive process. It is considered, however, that the following points deserve a closer examination. 1. As pointed out by Wyllie and Spangler1 the displacement pressure PD i.e. the pressure required to initiate the displacement of the wetting phase from the core, is a measure of the maximum pore diameter dmax. If the capillary pressure Pe as a function of the wetting

Jan 1, 1956

By Frederic P. Dewey

By the old method of determining platinum in ores and bullion, the silver-alloy first obtained in the regular course of assay is parted in strong sulphuric acid and the residual metal weighed. This is re-alloyed with silver by a second cupellation and parted in nitric acid, the residual metal being again weighed. Any difference shown between the two weighings is assumed to be, and is called, platinum. Sometimes it is SO, and if any considerable amount of platinum be present, there will be a decided difference between the two weighings; but a slight difference is no real evidence whatever of the presence of platinum. On the other hand, the second weight may equal or possibly exceed the first, even when traces of platinum are present. Again, other members of the platinum group may go into solution in nitric acid more or less. If present, these would be called platinum and escape detection. The method does not provide any direct tests whatever as to the presence or absence of platinum. It is often indecisive, and sometimes gives erroneous results. It is, therefore, quite unsatisfactory. Being called upon many times to determine platinum in a wide variety of materials, particularly when present in very small amounts, I have realized the disadvantages and defects of this old method. In an article on the solubility of gold in nitric acid,' I have briefly outlined a method of gathering a little gold out of a solution containing much silver, which furnishes the basis of

Jan 1, 1913

S., at Niagara Falls, as an expert chemist. There he was engaged in perfect.ing the various kinds of gases, and while thus employed was gassed several times, which so affected his heart and lungs that he was unable to withstand an attack of the influenza which developed into pneumonia, from which he died at the end of 24 hours. He was a member of St. Luke's Episcopal Church, Lebanon, and belonged to the Ancient Accepted Scottish Rite of Freemasonry, Lebanon Lodge 121, I. 0. 0. F. and Camp 65, P. 0. S. of A. Lieutenant Bernhardt Edward Heine Bernhardt Edward Heine, a lieutenant in the Aviation Service of the U. S. Army, died as the result of a fa1I1 in an aeroplane at Fort Sill, Okla., on Aug. 10, 1918. The accident occurred on Aug. 2, when the machine in which he was flying with Lieutenant Carsons fell from a height of 1500 ft.; Lieutenant Carsons was instantly killed, but Lieutenant Heine died from his injuries a week later. Lieutenant Heine was born at Mount Clemens, Mich., in 1895. After attending the local High School he entered the Michigan College of Mines, and became a Junior Member of the Institute while still a student. He graduated in 1916, with the degree of B. S. In 1914 he served as a transitman for the engineering department of the City of Hancock, Mich. Lieutenant Heine had been in the army since 1916, having been with the 'troops at 'the Mexican border. He had been in the Aviation Section since August, 1917.

Jan 1, 1920

By Paul R. La Pointe

GEOTECHNICAL OBJECTIVES OF UCG PROGRAM Underground coal gasification (UCG) is one of several in situ extraction technologies for utilizing deep, otherwise unmineable coal. This technology involves the injection of air or oxygen into the target coal seam, ignition of the coal and recovery of product gases. Geotechnical characteristics of the coal and enclosing rock strata strongly influence the success of this Process. The flame front follows the coal cleats (Hill, 1979), and cleating and bedding control the manner in which coal collapses into the cavity, thereby affecting recovery efficiency (Ramirez and others, 1982). Moreover, coal seams typically behave as fracture dominated aquifers in which cleat orientations govern subsequent contaminant dispersal. For these reasons, the Anaconda Minerals Co. undertook a detailed study of fracturing within the Wyodak-Anderson Coal in the eastern Powder River Basin (PRB) near its Rocky Hill UCG test site (Fig. 1). STRESS HISTORY AND FRACTURING IN THE POWDER RIVER BASIN Vertical jointing, or cleating, in coals may arise from shrinkage shortly after deposition under low confining pressures, or later in time, soon after burial but after the coalification process is well advanced (Ting, 1977). There is much evidence to support the formation of cleating after coalification (e.g. Hawkes and Mellor, 1970; McCulloch and others, 1974), which suggests that the stress state existing at that time strongly influences cleat formation. McCulloch and others (1974) argue that the typically better developed face cleat forms parallel to the plane containing [ol] and [o2]. Where the relation between cleats and stess has been studied (McCulloch and others, 1974; Stone and Snoeberger, 1977; Ward, 1977; Kulander and Dean, 1978), the highly systematic face cleat strongly parallels the [o1] direction. Stone and Snoeberger (1977) report face and butt cleat measurements of N70E and N29W for the Felix Coals 220 m stratigraphically above the Wyodak at the Hoe Creek UCG site (Fig. 1). Structural trends also indicate the past state of stress in the PRB. Glaze and Keller (1963) suggest that the NE-SW regional compression during the late Permian formed major N-S fold lines and basement magnetic anomalies. Mapel (1959) describes folds having N60W and N30W rends in the northern PRB, as well as a large normal fault trending northeast. Glass (1976) also describes normal faults trending northeast. Similarly, Olive (1957) mapped normal faults

Jan 1, 1984

Meeting; May 23, 1913.-On the petition of 25 or more members residing in the different localities, the following Local Sections were established: St. Louis Local Section. Southern California Local Section; Denver Local Section. It was voted to publish a statement in regard to tours in connection with the Butte meeting, which-is published on p. i of this Bulletin. Mr. Edward Caldwell was appointed as expert advisor. on printing. The report of the Committee on Printing advising certain changes in methods of printing. was accepted.

Jan 6, 1913

By W. E. Field

In the Coast Mountains approximately 110 miles north of Vancouver, the gold mine of Bralorne- Pioneer Mines Ltd. lies at an elevation of 3500 ft. The deepest or 41 level in the mine is at an elevation of 1400 ft below sea level, and the rock temperature on this level is 122.5°F. The thermal gradient is 1 "F increase in temperature for each 67.5 ft increase in depth. The mine produces between 500 and 600 tons per clay, utilizing an adit two internal shafts, and one service shaft from surface. The Queen shaft, extending from the 26 to the 41 level, IS the deepest, and most production now comes from this area. Stoping in by cut and fill using mill tailing hydraulic backfill.

Jan 12, 1963

By David S. Cahn

Pilot-plant and laboratory tests were made on blends of steel plant flue dust and portland cement to determine whether the flue dust could be pelletized for use as a source of iron in dry process cement manufacture. Strength and setting time results showed that an acceptable agglomerate can be made with a Type II portland cement binder. Abrasion-resistant and well-sized pellets were made in a horizontal drum, using a simulated closed circuit, with a binder content of 7.5% and a moisture content below 15%. Pellet quality was found to be relatively insensitive to changes in binder concentration above 5%. Simulations of stockpiling and weathering indicate that little difficulty would be encountered with use of the flue dust pellets in cement plants.

Jan 1, 1972

Discussion of the paper of BOYD DUDLEY, JR., presented at the New York meeting, February, 1915, and printed in Bulletin No. 96, December, 1914, pp. 2767 to 2782. H. 0. HOFMAN, Boston, Mass.-At the close of the paper Mr. Dudley said that his experiments in the laboratory had shown that it was possible to separate nickel from copper by means of a chloridizing roasting, but that in order to demonstrate a process of this kind, work upon a large scale would have to be carried out. I think it was in 1913, that experiments of this kind were carried out at the works of the Pennsylvania Salt Manufacturing Co., Philadelphia, in a Wedge furnace, and at Sault Ste. Marie in a Sjöstedt furnace. They showed a satisfactory separation of nickel and copper. The ore was first subjected to an oxidizing roast, then mixed with pyrite and salt, and given a chloridizing roast. A. H. Carpenter published in the Engineering and Mining Journal, vol. xcvii, p. 1085 (1914) the details of this work. The conclusion arrived at is, that if you subject sulphide ore to an oxidizing roast, finishing at the temperature at which all nickel sulphate is dissociated, i.e., 764° C., then mix it with pyrite and salt, and subject the mixture to a chloridizing roast between 600° and 700° C., you can chloridize a high percentage of the copper without chloridizing any of the nickel, and obtain thereby a satisfactory means of separating the two.

Jan 5, 1915