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By N. A. D. Parlee, I. D. Shah

ThIS reports on some work done on the solubility and diffusivity of oxygen in liquid silver. Solubility. Improvements in the measurement of the solubility of oxygen in silver and silver alloys were made because precise data were needed for calculating diffusion coefficients of oxygen in these alloys. The apparatus and the procedure used were similar to those of Parlee and Sacris.' The main improvement was in the temperature-measuring technique. A MV30 mullite protection tube containing a calibrated Pt-Pt, 10 pct Rh thermocouple was inserted in the reaction tube from the top through a vacuum-tight swage-lok fitting. The protection tube was well-immersed in the liquid silver, which was heated by induction. A Leeds and Northrup potentiometer was used in connection with the thermocouple. All runs reported were made at 1 atm. The temperature range investigated varied from 940" to 1200°C. The ternary point in Ag-0 phase diagram2 is at 939°C and 0.32 wt pct O. This point was reinvestigated using the above-described apparatus and was found to be at 939°C and 0.315 wt pct 0. It was determined by observing the sudden evolution of oxygen at this point while the solubility measurements were made. The point was easily reproducible if precautions were taken to keep the liquid silver essentially in equilibrium with oxygen and to lower the temperature very slowly. All of the results of this new solubility investigation are plotted in Fig. 1. They are represented by the "least-squares" line shown in the figure and the following equation for solubility at po2 = 1 atm: log% O =695.4/T - 1.086 This equation differs only slightly from that proposed by Parlee and sacrisl and that of Diaz, Masson, and Richardson.3 The points of Parlee and Sacris, using an optical pyrometer, are shown for comparison.

Jan 1, 1968

By H. Kurushima, S. Tsunoda

An investigation of the hydrometallurgy of Cu-Zn concentrates by The Dowa Mining Co. of Japan is described and a detailed flowsheet of the Kosaka hydro-metallurgical plant is given. Sufficient operating experience has shown that the Dorrco FluoSolids system has proven successful for recovery of both zinc and copper by roasting in a fluidized bed. At present, 2400 metric tons of concentrates per month are being treated and recoveries of 93 pct Cu and 65 pct Zn are being effected. A SURVEY of the Japanese chemical industry in 1949 revealed, among other things, that sulphur-bearing blast furnace gas from the Kosaka smelter of The Dowa Mining Co. Ltd., Kosaka, Japan, was being exhausted to the atmosphere as waste. In addition, it was costing that company an average of ten million yen ($28,000) annually for damages to the surrounding property caused by the sulphur dioxide in the gas. It was recommended by this survey that the gas be utilized for the production of sulphuric acid by the contact process. Mr. Kurushima visited the United States in May 1950 to investigate the engineering, construction, and operation of a contact acid plant. Any acid produced at Kosaka would necessarily have to be 98 pct H,SO, to prevent corrosion in railroad tank cars transporting it to the point of use. However, the production of 98 pct acid requires constant volume and SO, content of the gas. As the converter gas at Kosaka fluctuates in both volume and quality, it was decided to evaluate the smelting process with relation to other methods of recovery. This evaluation revealed a relatively new type of roaster, the Dorrco FluoSolids reactor, which was reported to be capable of roasting the copper sulphide concentrate in an excess of air with the production of an SO1 gas strong enough for acid production and a water-soluble copper sulphate calcine. The copper sulphate then could be leached from the roasted ore and electrolytic copper recovered from the leach solution in much the same manner as practiced by the Chile Exploration CO. for treating naturally occuring copper sulphate ores. Use of a reactor of this type would eliminate the need for a blast furnace and converter and, in addition, would effect savings in labor and fuel. The Kosaka ore is a microscopically fine mixture of copper, zinc, and lead sulphides. The lead and a small amount of the barite present can be separated by flotation, but any separation of copper and zinc proved extremely difficult. In blast furnace operation at Kosaka, zinc had been slagged off until a stockpile of about 12,000,000 tons containing 5 pct Zn had been accumulated. Mr. Kurushima felt that if any of the zinc in the concentrate was sulphat-ized and leached with the copper, it also could be recovered electrolytically. The Dorr Co., sponsors of fluidization technique in the metallurgical field, suggested that sulphate roasting be tested out on a laboratory scale and that, if successful, a commercial Dorrco FluoSolids system be constructed. They indicated that the results from such laboratory tests could be transposed to a commercial scale without pilot planting the roasting operation. It was therefore decided to send samples of flotation concentrate to the West-port Mill, laboratories of The Dorr Co., for testing. The objective of Mr. Kurushima's visit to the United States thus had changed from investigation of sulphuric acid plants to a fundamental examination of the hydrometallurgy of copper and zinc. Testing Program In February 1951, Mr. Tsunoda went to the United States to witness the application of the FluoSolids system to sulphate roasting at The Dorr

Jan 1, 1956

By Frank B. Gilbreth

The problem of the crippled soldier in industry is not a problem of war work only; it is a problem of industrial development. As individuals, each one of you is seeking to provide our maimed heroes with such teaching as will render them, in the shortest possible amount of time, productive and satisfied members of the community. As individuals you are interested in the organizations that are preparing to receive these men, to train them and to place them at that work for which they are best fitted. As an organization, it is now your duty to take up the industrial end of the problem, to investigate existing conditions in the industries, to discover where the opportunities for employment lie, and so readjust industrial practice that the cripples may be utilized to their own and the community's good with the least shock to themselves or to the industries, and with the greatest amount of permanent benefit to all concerned. We have divided industrial opportunities suitable for cripples, roughly, into three classes. First, such as already exist in the industries, which can be set aside for cripples only, present occupants being transferred to other work for which they can be fitted but which is not suitable for cripple work; second, opportunities in the industrial world that, through changes in the working equipment or tools, or through appliances attached to the cripple himself, can make the cripple a competitor of the sound worker; third, opportunities not existing at present in the industries, but which could be introduced for the good of the community without placing the cripples into competition with any existing class of workers. As typical of the first type of occupations for cripples, we have mentioned that of store-keeper, of the second type that of typist,2 and of the third type that of dental nurse.3 The last occupation can be so arranged as to take from the overworked dentist the work of cleaning teeth; and

Jan 1, 1918

By J. F. Gormley

Drill pipe, and the connections used to join the pipe together, have had a long history of development and improvement. With the growing use of high tensile-strength pipe, the rotary shouldered connections used to join the lengths of drill pipe have become more critical. Fatigue-type failures of rotary-shouldered connections, or tool joints, have become a cause of much conern to operators and manufacturers. Most fatigue tests on tool joints have been made on the basis of bending moment applied vs number of cycles, rather than on the basis of stress vs cycles. A desire to learn more about the nature of stress in a tool joint due to bending caused a rather intensive experimental study to determine what actually happens to cause fatigue failure. It was known that a tool joint with insufficient make-up torque was subject to early fatigue failure. Therefore, the establishment of the relationship between make-up torque and allowable bending moment would enable a testing engineer to better correlate the results of various tests. The problem of calculating the stress in a tool joint due to an applied bending moment was complicated by: the effect of unknown stress concentrations; the applicability of the well known formula S = Mc/I; and the question of whether to use the combined cross section of the pin and box in calculating the moment of inertia I. TEST EQUIPMENT The test equipment consisted of the following. 1. A lathe modified to act as a fatigue machine for full-size tool joint or drill-collar specimens. 2. An adapter plate bolted to the headstock of the lathe and into which a short adapter was screwed. 3. Tool-joint pins on sections of drill collars bucked into the adapter. 4. A hydraulic load cylinder which rested on the bed of the lathe and applied bending moments to the joints. 5. Paper-backed strain gauges (FAP-12-12, 1/8-in. gauge length and A-5-1, 1/2-in. gauge length). 6. Eastman 910 contact cement for bonding gauges to joint and Epoxylite 222 waterproofing. 7. A 12-position switchbox, SR-4 bridge balancing unit connected to an SR-4 strain indicator to read the gauge output. 8. A four-channel Sanborn recorder, Model 150, was used as the readout instrument for part of the testing. The fatigue machine was well suited as a loading device. Because of the long lever arm available, the change of moment with distance was small; consequently, the vertical shear stress was small, less than 300 psi. Some difficulty was experienced with the hydraulic load cylinder at high bending moments due to leakage. The strain gauge equipment was simple and quite reliable. A 41/2-in. extra hole (E. H.) joint with "as machined" threads and shoulders and a 2 7/8-in. internal flush (I. F.) joint with copper-plated threads and shoulders were selected for testing because of their common usage in the field. In addition, the 4 1/2-in. E. H. was suitable because it had an inside diameter large enough to permit the insertion and accurate positioning of strain gauges without using special jigs, while the 2 7/8-in. I. F. joint required much lower bending loads to cause separation of the shoulders of the joint when made up to the recommended torque. The joints were made to standard API specifications, except for very small bevels on the box and pin shoulders and cylindrical stress-relief grooves added to the pins. Larger bevels would have

By Jasper Stuckey

THE object of this paper is to record and interpret field and laboratory observations made by the writers during five years of study of the barite deposits of North Carolina. Deposits of barite are known to occur in three localities in North Carolina (Fig. 1) two of which-the Hot Springs and Kings Mountain -contain material of economic value. The Hot Springs area begins near Bluff, some 6 miles south of Hot Springs, and continues northeast by Stackhouse; a total length of 7 miles. The Kings Mountain deposits lie along a belt that extends from the north end of Crowders Mountain in a southwestward direction, along the east side of this and Kings Mountain, to Kings Creek, South Carolina. The third locality is 3 1/2 miles southeast of Hillsboro, Orange County, a short distance west of the highway leading from Hillsboro to Chapel Hill. It is not known when barite was first discovered in North Carolina, but production from the Hot Springs area began some 50 years ago. The state has never produced large quantities of barite-usually there have been less than three producers-and definite figures are not available, but reasonably reliable estimates indicate a total production of 300,000 tons. From 1901 through 1920 barite mining was on a seemingly prosperous basis and a large tonnage. was shipped from the Hot Springs and Kings Mountain areas. With the depression of 1920 the industry began to decline and production practically ceased in 1926.

Jan 1, 1933

By H. J. Wasson

With the close of 1932 and the third year of the depression, the activity of oil production presents, amidst the general wreckage and chaos of industrial society, a somewhat unique picture of rationalized economic effort. How long it will continue to present such a picture, however, is a subject for conflicting surmises. East Texas still dominates the contemporary horizon, but it has become, at least for the time being, a definitely known factor. With its 9500 wells it is approximately 90 per cent drilled up. So long as production control obtains, it is merely one important factor of the national oil reserve. Domestic Production The notable new discoveries in the United States were less numerous than for several years. Elsewhere in the world the record is much the same. The Conroe field in Montgomery County, Texas, lying in an intermediate zone that might be classified either as Gulf Coast or East Texas, represents perhaps the single example of a truly major discovery during the year. Elsewhere in Texas the new pool discoveries, about a dozen or so in number, were nearly all in the region known as Southwest Texas. Oklahoma contributed seven or eight new pools of the routine "run-of-mine" caliber, and the opening up of a few deeper oil pays also were of some significance. Continued expansion of the proved and semiproved reserves in Kansas added an important increment to the oil resources of that state. In California not a single new field was added to the roster, though deeper pay zones equivalent to or of greater importance than many new fields in other parts of the country were discovered or indicated. The new deep zone in the Belridge field is considered by some to underlie the prolific Temblor and may thus forecast the widespread distribution of a potentinl oil horizon underlying many San Joaquin Valley fields below the depths thus far exploited. Aside from the routine operations in connection with settled production, the Eastern fields were decidedly inactive. Further new develop-

Jan 1, 1933

By Brian J. Gorval, Robert L. Kemeny

INTRODUCTION Financing, or providing adequate capital at low cost for developing and bringing a natural resource property into production, is a fundamental requirement for profitable operation. Under the present economic environment the cost of financing any project is gaining more importance than ever. The fundamental keys for success in mining are "the Four M's": Mineral, Market, Management and Money. In recent years, with capital and operating costs skyrocketing, increased emphasis on obtaining adequate and low cost capital funds for bringing in a prospect is essential. For a small mining company there are limited sources for raising funds. In most cases these companies have neither a substantial asset base, nor any cash flow, and they are deemed as risky investments. The issue of shares of capital stock of such a company is probably the most common method of raising funds via the public purse. Alternatively, debt could be used and a source of such capital might be private investors or financial institutions. The company which intends to raise funds from the investing public by way of the sale of equity, subsequently lists those shares for trading on a stock exchange. Going and staying public commits a company to a multitude of complex laws, rules and reporting requirements. The governing bodies are the watch dogs for the public. The largest of such an organization of this kind in the world is the Securities and Exchange Commission (SEC) in the United States. In Canada, the Securities Laws come from within provincial jurisdiction. Most provinces have their own Securities Act, and Securities Commission. It is the Commission which administers the Act, and hence controls the distribution and trading of securities within the province. Extra provincial registration is required for trading and distribution in more than one province. In British Columbia, prior to a public offering, the approval of the Superintendent of Brokers (SOB) and of the VSE must be obtained. THE VANCOUVER AND TORONTO STOCK EXCHANGES There are five stock exchanges in Canada which supply a trading forum in which mining companies may operate. The stock exchanges are located in Montreal, Toronto, Winnipeg, Calgary, and Vancouver. Of the five stock exchanges, the Vancouver Stock Exchange (VSE) and the Toronto Stock Exchange (TSE) are the most heavily used for resource-based issues and are the focus of this paper. The objective of this section is to provide a brief background on the VSE and TSE. The Vancouver Stock Exchange The VSE is Canada's predominant stock exchange for financing resource-based, junior issues. Since 1907, the VSE has acted as a source of funds for mining, exploration and energy companies throughout Canada and the world. Currently, there are over 1400 companies listed on the VSE. During 1983, over 3.1 billion shares traded at a value exceeding CDN$3.96 million. The VSE has developed a reputation as one of the few exchanges where a speculative resource venture may obtain a listing and subsequent financing in a relatively short time, generally five to ten months. The SOB, the Investment Dealer's Association of Canada (IDA), and the VSE all regulate trading at the Exchange. Any irregularities in a company's stock dealings are investigated and trading may be halted by the VSE until a satisfactory explanation has been received from the suspended company. Companies can be suspended from trading or delisted for various reasons. One reason is misrepresentation of facts in documentation submitted to the SOB, VSE, or to the public, through news releases.

Jan 1, 1985

The Ural Mountains, which were formerly the dividing line between Asia and Siberia, area chain of low mountains, the highest peaks reaching only a little over 5000 ft. The country has been much eroded and the mountains now appear as rounded hills. In the central and northern parts turf swamps abound. The range is covered with forests except at the extreme southern end. The trees are mostly pine. Birch grows on cut-over areas, but never to large size. The rivers are small or the fall is slight, so no large water powers are available. A series of rivers with a north and south course, and which are navigable for long distances, furnish cheap transportation during the summer months. Railroad communications are very insufficient. The first active exploitation of the mineral wealth was initiated by Peter the Great, who sought iron and copper for use in his wars against the Swedes. He selected a blacksmith named Demidoff to supervise operations and gave him rights to most of the Ural and to the Altai. The Nijni Tagil Estates are still in the possession of the Demidoff family. The original large grant was subsequently subdivided through inheritance and marriage, but the Ural is still a country of very large estates, some of them held as leases only and some of them by actual ownership.

Jan 6, 1919

By Walter Miller

ALTHOUGH confident of its ability to meet any demands which may be made, the petroleum refining industry is not complacent about the situation and realizes that the quantities of petroleum products to be furnished are so enormous and so far beyond what was previously estimated that the full co-operative effort of the industry must be exerted. Establishment by the President in May of the Office of Petroleum Coordinator for Defense with Secretary of the Interior Ickes at its head, plus the formation of the Petroleum Industry Council for Defense, in November, provide the channels for united endeavor within the industry and the means for gearing that endeavor within the industry and the means for gearing that endeavor in full harmony with the nation?s needs. Great strides have been made and a rapid understanding of the situation and the magnitude of the task is being attained by all concerned.

Jan 1, 1942

By W. P. Lass

Discussion of the paper of W. P. LASS, presented at the San Francisco meeting, September, 1915, and printed in Bulletin No. 103, July, 1915, pp. 1443 to 1447. ROBERT M. KEENEY, Somersville, Conn. (communication to the Secretary *).-There is not only a possibility of improvement in present methods of treatment of the byproducts of refining in the cyanide plant by the use of the electric furnace, but also in melting and refining of gold precipitate. This interesting paper by Mr. Lass shows an electric furnace in successful operation in a large plant for the treatment of by-products. Electric melting of cyanide precipitate is a cheaper form of treatment in many cases than any of the combustion methods now used because of the high cost of oil, coke or coal in many camps, while on the other hand electric power may be had cheaply, especially in a place where there is possibility of development of high-head hydro-electric plants for power purposes. Also, if the oil-fired tilting furnace is used for direct melting of the precipitate, as is the case at many small mills, a great saving in cost is made by the use of the electric furnace because of the high crucible cost in melting with the tilting furnace. A study of this paper indicates the cost of the operation approximately. Consider all the fluxes to be turned in as byproducts and coke at $18 per ton.

Jan 12, 1915

By J. Y. Oldshue

INTRODUCTION The field of fluid mixing involves many different kinds of process objectives. In order to classify these objectives, Table 1 gives a listing of five basic application categories, gas-liquid, liquid-solid, liquid-liquid, miscible liquids, and fluid motion. However, each of these areas can be broken up into two different concepts one involved with uniformity of solids or liquids as a criteria, and the other involved with chemical reactions or mass transfer. The things that we would do to design a fluid mixing for solid suspension are quite different from things that we would do to design a mixer for heat transfer or gas-liquid mass transfer. Therefore, there are really ten separate mixing technologies. Each of these areas has its [ ] own principles of fluid mechanics, scale-up techniques and application experience. We will take a look at each of these areas and look at some of the ways that we can handle fluid mixing applications which.

Jan 1, 1979

Cycle, automatic, in mine hoists, LV, 17. Cylindrical furnaces, repairing partly collapsed, XXXVI, 215-222. Dacite-porphyry, San Jose, Tamaulipas, Mex., percentage composition, XXXVI, 186. DAGGETT, ELLSWORTH: The Extraordinary Faulting at the Berlin Mine, Nev., XXXVIII, [liii], 297. Daiquiri, Cuba: geology, LIII, 3, 43. iron deposits, LIII, 40. Magdalena mine, LIII, 9, 23, 24. mines, bibliography, LIII, 59. situation of mines, LIII, 42. [ ]

Jan 1, 1918

By L. D. Clark

Pay-out, the ratio of capital expenditure to annual cash return can be very revealing when employed to gage the merits of a proposed mining venture. It is a quantity, numerically but not physically equal to a factor, by which cash return may be discounted to equal required investment. The fewer the pay-out years, the greater the average annual earning power of the project. Considerable material has been written in the past about the most important and difficult problem mining management faces in evaluation of a property: the optimum production rate for the venture. What daily capacity should be adopted for the proposed operation that it may be the most rewarding to those underwriting it? H.C. Hoover has said, "The most important objective is the least cost per ton mined; and minimum working costs can only be gained by the most intensive production." Theoretically and practically, the quicker the ore is removed, the more profitable should be the venture because of the saving in fixed charges, the consequent lower unit costs and the interest unearned by the profit from the unmined ore. Yet, such performance will be tempered by policy and a restraint imposed by the ratio of capital expenditure to annual cash return. * The 'Annual net profit after taxes but including depreciation and depletion allowances. former will be based upon an analysis of the economic climate anticipated, with its many ramifications including the demand for the product, prices, tax laws, the conduct of labor and related wage scales. The variables and intangibles involved in estimating the optimum production rate for a mine do not readily lend themselves to mathematical relationships or equations and the problem can become complex indeed. The more readily applicable and relatively faster appraisal method will be used which, in addition to being reasonably adequate in most cases, will serve as a guide, should a more expanded and detailed estimate be desired. The first question is what is company policy with respect to the rate of investment return? This will depend on that significant period of time referred to as the pay-out, which can be defined as the estimated interval during which capital investment is returned through application of annual cash return to its recovery. Expressed another way, it is the ratio of capital expenditure to the annual cash return. For example, if the capital investment is $C and the annual cash return is $A (after Federal tax), then $C/$A = the pay-out period in years. That is to say, if $C = $1,500,000 and $A = $214,000, then which is the mathematical expression for the period of time it takes to recover the funds originally invested in a mining enterprise. The relationship yp = $C/$A can be useful — an expression which requires only the significant tern yp to be fixed; in other words, the long range investment policy. For what is the pay-out period but an expression of that policy in terms of the speed, within practical limits, with which an individual or company may want to recover capital expenditure? A policy by which pay-out will be fixed is imperative. This ratio must lie within relatively narrow limits governed by what is economically feasible. It cannot be too low, rendering the ratio impractical or absurd, nor too great, delaying the return of capital for reinvestment beyond a commensurate interval. What pay-out will govern this policy? Federal corporate taxes would seem to present the best measure. Consider mining in Canada where new mines are exempt from Federal income tax for 3½ yr from date of first production. This exemption expressly allows The Act states: "A corporation . . . i s not required to include the profits . . . for the period of 36 months commencing with the day on which the mine came into production in reasonable commercial quantites." a company to recover capital expenditure during the early stages of production. With such an incentive, it is logical to strive for as much capital redemption as possible during this period. Thus, 3½ yr would be a major contribution to the pay-out in Canada. Furthermore, it generally takes from 1½ to 3 yr to develop

Jan 1, 1963

By F. E. Jaumot, A. Sawatzky

IT as long been recognized that there is a need for accurate systematic data on diffusion in solids. Originally, such data were needed to check existing theories but, more recently, it would appear that it could be used most advantageously as a guide to, or a check for, much needed extensions of the theory of diffusion. The awareness of the conditions which are important to experimental accuracy, the availability of the materials for accurate experiments, and the techniques have improved to the extent that it would now seem to an experimentalist that, unless extensions of the theory are made which take into account the fundamental parameters of the atoms, the electrons, and the lattice in some detail, the field of diffusion will rapidly become an empirical or semi-empirical field. The present series of experiments was designed to provide accurate data on the diffusion of the elements of the IB and IIB subgroups in silver; that is, to provide data on the diffusion in silver of three face-centered-cubic elements with roughly similar chemical properties, but with different atomic or ionic sizes and, similarly, for three noncubic elements. The elements of these two subgroups have different valences, so that the data will not give any significant information on differences due to the crystal structure of the solute. The present paper reports data on the diffusion of copper and mercury in single crystals of silver; the data for the other elements of the IB and IIB subgroups were reported previously by the authors1'2 and by Tomizuka and Slifkin.8 Experiment The general technique used was identical to that previously described1,2 and will not be repeated here. In all cases, the sectioning technique and high specific activity isotopes" were used. The short half-life of Cu64 made decay corrections more important than for the other isotopes, and necessitated around the clock shifts while data were being taken. Each section was counted at least twice (as was true for all longer half-life isotopes) and a monitor was counted along with each sample. Data for the diffusion of mercury in silver are presented at a greater number of temperatures than for the other solutes. This is a result of two circumstances. First, six (of 30) samples had to be discarded because of pitting or recrystallization which occurred during the diffusion runs, even though the samples had sustained high temperature prediffusion anneals. Either of these was a very rare phenomenon in the other experiments, and their occurrence in this case is considered in more detail below. Second, the curves of the logarithm of the activity of the sections vs the square of the penetration deptht were, in general, quite good, but frequently seemed to show one point to have high activity and the next point to have slightly low activity in terms of the best straight line. When this occurred, there was remarkable regularity of the high-low sequence. In any event, the results, as far as diffusion coefficients are concerned, were not affected by this amalgam effect. In fact, the mercury data had the highest internal consistency of any of the data. Results Diffusion of Copper in Silver—-Diffusion runs were made at eight temperatures In the temperature range from 700° to 950°C, for times ranging from 5 to 45 hr. A linear curve of the logarithm or the activity vs the square of the penetration depth was obtained for all samples. Table I summarizes the results for individual samples and Fig. 1 gives a plot 02 the logarithm of the diffusion coefficients as

Jan 1, 1958

By R. B. Walker, R. Palmer, L. C. Bryner

The purpose of this investigation was to further study some of the factors affecting the air oxidation of sulfide minerals. Data obtained from laboratory studies on the effect of temperature, concentration of iron salts, pH, and other catalysts on the biological and nonbiological oxidation of sulfide minerals are presented. The oxidation of copper sulfide minerals and subsequent leaching of the soluble copper has long been a profitable operation. The chief oxidizing agent is oxygen from the air. This reaction is influenced by a number of different factors such as temperature, light, hydrogen ion concentration, oxidizing agents, and various catalysts. Sullivan1 found that copper sulfide minerals are slowly oxidized by the air and that dilute sulfuric acid and iron (111) increased their solubility. At that time it was not known that bacteria were involved in the oxidation of the sulfide minerals. It has been shown that pyrite, molybdenite, free sulfur, and the copper sulfide minerals found in the waste rock dumps in Bingham Canyon, Utah, are largely oxidized by chemosynthetic autotrophic microorganisms found in the leaching streams.2-6 Similar organisms have been isolated in other mining areas7,8 and from the effluents from coal rnines.9 The following are some of the questions that have arisen regarding the mechanisms of the reactions involved in the leaching process. How dependent is the leaching operation upon the biological reactions? How does the temperature effect the biological and non-biological reactions? How does the concentration of iron (II) and (111) effect the rate of oxidation of copper (II) sulfide? Does the iron act as a catalyst? Does activated carbon act as a catalyst on the oxidation of sulfide minerals? What effect does the hydrogen ion concentration (pH) have on the above reactions? The purpose of this paper is to report the results of laboratory studies on these problems. EXPERIMENTAL The apparatus used in this investigation was an air lift percolator described in our earlier work.' The percolator consisted essentially of an air lift which enabled the leaching solution and microorganisms to pass freely through a suspension of mineral (substrate) in Ottawa sand. The air lift served the additional purpose of maintaining an ample concentration of oxygen and carbon dioxide in the nutrient (leaching) solution. (See Fig. 1.) The percolators were so constructed that they could be immersed in liquid constant temperature baths for temperature studies. The thermostats were controlled to +0.5°C. The reactions were all run in the dark. The percolators were charged with one to three g of mineral, dispersed in 100 g of Ottawa sand and 100 ml of nutrient or leaching solution. The sand was purified to remove traces of iron by digesting with concentrated hydrochloric acid and washng with distilled water until free from chloride. After drying, the sand was ready for use. The compressed air supply was regulated to 5 psi and bubbled through an aerator containing distilled water, which was maintained at the same temperature as the bath used. The air was filtered through cotton plugs to maintain sterile conditions. The tops of the

Jan 1, 1968

By James Lorimer

THE topography at the Stan Trg mine facilitated early exploration by adits; in consequence adit levels were developed at horizons 865, 795, and 760 meters above sea level, and the levels in the mine 'are named according to their elevation. Exploitation started from the 760-m. level . upwards while simultaneously first steps were taken with regard to mining in depth. A deep dewatering adit 2.5 km. long now gives access to the deposit at the 610-m. horizon which also is connected with the 760-m. adit level by a three-compartment main hoisting shaft. Main levels have been developed internally from

Jan 1, 1936

By G. L. Oldright, Virgil Miller

It is well known, in metallurgical circles, though less recognized in the technical press, that there have been remarkable increases in the capacity of the blast furnace in the last five .years. In places this capacity has been almost doubled. This paper will brief the experimental work carried on during more than five years with the direct assistance of the technical staffs of three lead smelters treating three distinctive types of feed. The first is the custom smelter of the International Smelting and Refining Co. at Tooele, Utah1, with a multiplicity of ores; the second, the Kellogg, Idaho, smelter of the Bunker Hill and Sullivan Mining and Concentrating CO.2, treating an exceedingly rich lead charge, such as is now being made more and more as the practice of concentration is improved; and the third, the smelter at Trail, B. C., owned by the Consolidated Mining and Smelting Company of Canada, Limited3, which treats highly zinciferous charges and later recovers zinc from the slag. In comparing operations at these three smelters it must be clearly recognized that the objectives in smelting differ through differences in economics. Many operations are not, then, strictly comparable. There have also been decided improvements in operation since all of the smelters were examined, though this was but a relatively short time ago. The general factors that govern speed in smelting and the loss of metals in the smelters examined will be stressed. (For details of operation the reader is referred to the original papers.) This paper will then be an examination of the fundamentals of operating units in a search for improvements, and not a description of three great lead smelters. Capacity of Blast Furnace Assuming a well prepared and self-fluxing charge to start with, enough coke must be added: (1) to melt the charge, particularly the slag-forming

Jan 1, 1937

By AIME AIME

THE complete list of papers for the meeting of the Petroleum Division that is to be held" at Tulsa,' Thursday and Friday, Oct. 3 and 4,, with assignment to individual sessions is given below. THURSDAY MORNING First Session Well Spacing Theory of Well Spacing-By W. P. Haseman. Discussion by S. C. Herold, J. R. Suman and Lester C. Uren. Well Spacing in the Long Beach Field, California-By - Stender Sweeney. Discussion by C. H. McNeese; R. R Brandenthaler and W. V. Vietti. Well Spacing in the Bradford Field, Pennsylvania-By Paul D. Torrey. Discussion by A. F. Melcher, R. M.. Haskell, J. B. Umpleby and J. B. Newby. Results of Different Well Spacing in the Salt Creek Field, Wyoming-By Fred E. Wood. Discussion by Sam Grinsfelder and Kenneth B. Knowles.

Jan 1, 1929

Jan 1, 1890

By AIME AIME

EDWIN W. KEMMERER, professor of international finance at Princeton, in a speech before a banking conference at Urbana, Ill., on Nov. 26, stated that the increase in the store of gold held by the United States is not so alarming as it appears on the surface. Excerpts from his address, as reported by The New York Times, follow: "It is significant . . . that the value of gold as expressed in its purchasing power in the United States during the last half-dozen years has been higher than at any other equivalent period since our records began 140 years ago. Our so-called 59-cent dollar today buys about 25 per cent more goods at wholesale than did our old dollar in the prosperous year 1926, and an ounce of gold will now buy considerably more than twice what it did then. This present high value of gold is one reason for its recent large production.

Jan 1, 1941