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By Oliver Bowles

A NORTH CAROLINA miner dreamed that he found high-grade mica by excavating a certain corner of his mine. The next day he sank a hole on the exact spot and found mica of excellent quality. The dream came true. May not this be as good a method as any yet known for forecasting the valuable mineral content of pegmatites? The Federal Geological Survey has found in its recent detailed studies in New England that good sheet mica occurs most abundantly in zoned pegmatites, particularly in zones lying along the wall or contact of the pegmatite mass. Although this conclusion may be a valuable guide, pegmatite mining operations must still be classed as most uncertain and hazardous enterprises. Finding of the second largest diamond ever discovered in the United States-a stone of good gem quality weighing more than 34 carats-during the course of a horseshoe pitching contest at Peterstown, W. Va., is another example of unorthodox mining methods. These should not be considered, however, as characteristic mining methods developed in 1944.

Jan 1, 1945

By Paul M. Tyler

MILITARY power stems from industrial power and industrial power in turn depends predominantly upon an ample and assured supply of mineral raw materials. It thus becomes the duty of mineral economists to collate the vast array of data and logical deductions in order to reach an unemotional judgment as to the ability of the Soviet economy to withstand the strain of prolonged military action on the modern scale. Russian publications, reports: and official speeches have been laboriously screened and analyzed. Since these are the sources of information for the lower echelons of the Soviet industrial organization itself, they carry factual data that can be pieced together to show the present-day pattern. Apparent contradictions and obvious distortions or omissions can often be rationalized on the basis of observations made by foreign engineers and consultants during the 1930'5 and by checking against the technical literature published before even so-called technical articles were riddled by bombastic and presumptuous claims.

Jan 6, 1951

By George H. Deike

DURING the past year a survey was conducted by the Committee on the Promotion of Student Interest in Coal Mining to determine whether the program as laid down in past years was operating effectively. It is a source of satisfaction and pleasure to be able to report considerable headway among operating companies in putting cooperative scholarship plans into operation. In previous committee reports the pioneer work along this line by Eugene McAuliffe, president of the Union Pacific Coal Co., has been cited. That Company now has in its employ, in responsible positions, three men who received their education under such scholarship plans. One student under a similar plan is now studying at the Colorado School of Mines.

Jan 1, 1942

By A. Keith Brewer

RECENT advances in the fields of chemistry, biology, and metallurgy have confronted the analytical chemist with an entirely new set of problems. Development of plastics and synthetics has brought about a need, not only for adequate methods for their analysis but also for the various raw materials entering into their manufacture. The remarkable advance made in biochemical and agricultural research resulting from the use of isotopes as tracers or "tagged atoms" has established the necessity for the development of methods for the concentration of natural isotopes and for a means for their analysis. Similarly the advent of new and complex alloys calls for accurate analytical methods. Fortunately the analytical chemist has been able to meet some of these new demands by adapting to his purposes an instrument which has long been the most exclusive toy of the physicists. Solubility and the chemical properties of the atoms, which have always served as the basis for chemical analysis, do not enter into this new technique. Instead, momentum, defined as mass times velocity, is utilized as the means for the separation of atoms or mass groups.

Jan 1, 1946

By Paul F. Kerr

The insufficiencies of our mineral resources are becoming well known, and the national political conscience seems to be troubled at last by our dependence upon mineral commodities which must come from other lands. This realization places increased responsibility upon the industrial, educational, and governmental groups whose task it will be to solve the problems of mineral supply. As we all know, from the time that man first sought mineral deposits until recent years, prospectors have been largely responsible for mineral discoveries. Today the era of the prospector is almost over. The human ants that have literally examined all accessible outcrops and have tested the gravels of nearly all stream beds in the United States have left undiscovered few worthwhile mineral deposits within the scope of their recognition. The pages in the history of mineral exploration are now being turned from the era of the surface prospect to the era of the hidden de- posit.

Jan 1, 1949

By DONALD H. McLAUGHLlN

Few factors have had more influence in maintaining the strength and stability of the United States than our persistent habit of providing .checks and balances to the dynamic powers of free enterprise on the one hand and to the controls and guidance exercised by the State on the other. .Indeed, it is this same concern for matching forces against each other that has given our republic its ability -to preserve a democratic basis of life for its citizens, and yet maintain a ,government that is able to protect the rights of all and to resist and minimize the danger of excessive concentration of authority. Our current efforts to clarify the nation's mineral policies and to define more clearly the role that the governmental agencies should play in conjunction with the functions of private -enterprise again reveal the desirability and advantages of maintaining our traditional controls. At times, the equilibrium has been temporarily disturbed by too great enthusiasm for one or the other of these basic concepts. Sooner or later, however, the balance has been restored by the healthy opposition that is always created by excesses of one sort. At the current stage in our history, the swing toward undue enlargement of the powers of the State seems to have gone dangerously far and we would be untrue 'to our traditional behavior if the group that must demonstrate the virtues of free enterprise did not rally to its support with the utmost earnestness.

Jan 1, 1949

By R. D. Carpenter, R. R. Smith, E. E. Sougstad

The Union Carbide Nuclear Co., in treating low-grade tungsten and molybdenum-copper ores at the Pine Creek mill near Bishop, Calif., employs flotation for the initial extraction of the valuable mineral constituents. These minerals consist of scheelite, molybdenite, and several of the copper sulfides including chalcopyrite, bornite, and possibly chalcocite. They occur in a gangue consisting mainly of quartz, pyroxene, and garnet, with minor amounts of calcite and fluorite. This assemblage of minerals presents an unusual grinding problem because of their diverse physical characteristics. Feed for the circuit is prepared from -6-in. ore by screening on a rod deck screen to remove the -5/8 - in. material. The+5/8-in. fraction is crushed in open circuit with a 5 1/2-ft Symons shorthead crusher operated at a closed- side setting of approximately 3/8 in. The screen undersize and the conecrusher discharge are then combined to constitute the feed to the grinding circuit. The ore is ground in 6 by 5-ft grate discharge ball mills operated in closed circuit with 54-in. spiral classifiers. The classifier overflow goes directly to the flotation section of the plant. Studies of the flotation circuits have shown that the maximum recovery of the tungsten, molybdenum, and copper minerals occurs in the particle-sue range from 100 mesh to approximately 400 mesh. Further, practice has shown that the ore minerals are effectively reduced to this size range if the total ore is ground to -48 mesh. The general objective of the grinding circuit then is to reduce the feed to -48 mesh with the production of a minimum amount of slimes. The purpose of this investigation was to ascertain how well the grinding circuit was carrying out this objective. The method used was to sample the various products in the grinding section, size these products accurately, and analyze the resulting sue distributions. SAMPLE PREPARATION AND SIZING TECHNIQUES Representative samples of the different grinding circuit products, namely, new feed to the ball mill, ball mill discharge, classifier overflow, and classifier return, were taken over a 24-hr period. The samples were then dried without being filtered to avoid loss of slimes. The percentages of solids in the different products were the following: new ball-mill feed, 95%; ball mill discharge, 82%; classifier overflow, 52%; and classifier return, 84% solids. Particle sizes were determined on each product by wet-screening an

Jan 1, 1962

By A. M. Kivari

OPERATIONS at the cement plant of the Permanente Corporation, in the hills about 45 miles south of San Francisco and 12 miles west of San Jose, are interesting to the members because of the adoption of modern hydrometallurgical methods for handling and beneficiating raw materials. Closed-circuit grinding, classification, hydro-separation, flotation, agitation, and thickening are familiar terms at this cement plant. These methods make it possible to process refractory limestone into suitable materials for the manufacture of modern cements. Construction of the plant, having originally a design capacity of 7000 bbl. of cement per day, was started in June 1939, and the first clinker was ground on the following Christmas Day. At present the capacity is about 12,000 bbl. of finished cement per 24 hr., most of the production being low-heat cement.† About 3130 tons of limestone, 620 tons 0f clay and 100 tons of gypsum are required daily for this output. Occasionally iron oxide is added to the clay to obtain the desired composition. This, together with the gypsum, is purchased from outside sources. Up to the present time, the corporation has produced low-heat, normal, moderate heat, moderate-sulphate-resisting, high-early-strength, oil-well, modified-oil-well, and plastic cements. Most of the present production is for Shasta Dam, near Redding, Calif., the total demand being 5,800,000 bbl, of cement. Following are some of the cement requirements of the Shasta Dam specifications: [PERCENT Chemical composition: Loss in ignition2.25 Insoluble residue0.75 SO32.25 MgO5.00 Uncombined lime in clinker (CaO)1 .25 Percentage of iron oxide to alumina ratio1.5 Compound composition: Tricalcium silicate (3CaO.Si02)Not more than 3,5 Dicalcium silicate (2CaO.Si02)Not less than 40 and not more than 65 Tricalcium aluminate (3CaO.Al2O7)Not more than 7 Tetracalcium aluminoferrite (4CaO.A12O3.Fe203) Not more than 0 Fineness:] The average specific surface in the bin sampled shall be not less than 1800 sq. cm. per gram and no individual sample less than 1600 sq. centimeters. Compressive strength: The average compressive strength-in pounds per square inch of three mortar cubes composed of one part cement and 2.75 parts fine testing sand, by weight, shall be equal to or greater than the following:

Jan 1, 1941

By A. G. Buyers, J. Chilton, W. E. McKee

STUDIES in the high-temperature separations chemistry of thorium-uranium fuels are complicated by the corrosive nature of these molten metal systems at 1700°C. Separations research pointed toward the removal of fission products from irradiated alloys has included a frozen salt-bed technique which minimizes container reaction with molten metal. The procedure consists of high-frequency induction melting of the metal sample which is supported by a vertical column of unmelted salt. The molten alloy melts its immediate salt environment and as it slowly falls down through the column, many of the fission-product poisons are transferred into the fused salt environment. The molten salt-metal zone is encompassed at all times by unmelted salt, preventing container contact. EXPERIMENTAL Experimental methods were separated into three parts: salt-bed preparation, melting, and analytical evaluation. A) Bed Preparation—The procedure for casting calcium-fluoride briquettes was to compress the powdered salt at 5,000 to 10,000 psi and place this compact in a graphite crucible. This assembly was inserted into a vacuum system and surrounded by an alumina crucible as well as molybdenum, tantalum, or stainless-steel foil thermal-radiation shields. The pressure was reduced and the crucible heated under vacuum to about 800°C with the fore pump operating. Argon was then admitted to about 0.8 atm and heating continued until the CaF2 had melted 5 min at the melting point seemed satisfactory). Apparatus used included a 1-in. graphite crucible with 1/8-in. walls, 1-in. ID in a 2-in. induction coil, and a 6-kw Ajax high-frequency converter. B) Melting—Calcium-fluoride briquettes, 1 in. in diam and 1/2 to 1 in. thick, were prepared and vertically stacked to obtain the desired column length. An irradiated alloy sample (nut = 10") was placed on top of the salt column and the assembly was connected to the vacuum system. After evacuation of 5 to 10 , purified argon was admitted and the system flushed twice. The final argon pressure was about 0.8 atm. The sample was heated by induction at a power of about 6.5 kw. It then melted its way down through the salt and freely dropped into a small alumina crucible. The molten metal is followed during its downward course by the induction coil which is mounted upon a power-driven machine-threaded shaft. Experimental conditions used in the foregoing work

Jan 1, 1960

By S. S. Nosseir

INTRODUCTION General Quebec Cartier Mining Co. (QCM) , Canadian subsidiary of U . S. Steel Corporation, operates two iron ore concentrators at the North Shore of Quebec, Canada. In its own operation at Mount-Wright, over 45 million tons per year of crude ore are ground, fully autogenous in six 32' x 11-1/2 Dominion Engineering mills. At Fire Lake/Lac Jeannine operation, property of Sidbec Normines Incorporated (SNI), over 11 million tons per year of crude ore are now ground, fully autogenous, in twelve 18' x 5' Hardinge mills. The Lac Jeannine concentrator was originally constructed by Q.C.M. in 1960 and. was since operated, in beneficiating the Lac Jeannine ore deposit until fully depleted in 1977, at an annual capacity of 18 million tons of crude per year. In 1976, the new company, Sidbec Normines, was incorporated by Sidbec Corporation, British Steel Corporation and Quebec Cartier Mining Co., in proportional holding of approximately 51 to 41 to 8 percent respectively. Since the acquisition of the Fire Lake ore deposit and Jeannine concentrator by the new company, QCM has continued managing the mine and concentrator operaions for S idbec Normines Inc . Flow-Sheet Design Jeannine concentrator comprises twelve identical mill lines grinding the ROM from 8" top size to 14 mesh nominal size range. Driven by 600 H.P. motor at 13.4 RPM corresponding to 73% critical speed, each mill is operated in a closed circuit with two 5' x 12' vibrating screens dressed with 2.5 x 25 mm slot opening cloth. The ground product or screen undersize at an average grade of 33.4% Fe is beneficiated by gravity separation to produce 66.5% Fe concentrate grade at 42.7% weight recovery. At the rougher stage, each mill line con-tains 128 Humphrey 13- 1/2" pitch spirals which produce a final tailing, middling and concentrate products. The rougher concentrate - so produced - is classified by 64 Humphrey pocket sizers into an underflow, which is a final concentrate product and an overflow which is further upgraded by 64 cleaner spirals. The cleaner concentrate together with the pocket sizer 's underflow are dewatered on a 13'[6] horizontal filter. The rougher middling together with the cleaner tailing are recycled in a closed circuit with the spirals. The rougher tailing after dewatering by hydrocyclones is disposed of by a

Jan 1, 1982

By N. J. Grant, K. M. Zwilsky, J. T. Blucher

DISPERSION strengthening has been studied in a number of metal-metal oxide systems. To date those pure metals available as fine particles (less than about 5 p) have received most of the attention whereas solid solution alloys, generally unavailable as fine powders, have not been examined in detail. The present work was undertaken as a preliminary study to evaluate combined effects of solid solution and dispersion strengthening. The technique used was that of dry mixing of elemental powders with the oxide, followed by a diffusion treatment to obtain the solid solution. The average particle size of the powders used was: Ni, 3.2 p (1nco B); Mo, 1.3 p (Fansteel Metallurgical Corp.); and y alumina, 0.027 \i (G. L. Cabot, Inc.). The particle size of the metal powders was determined by Fisher subsieve measurements while the size of the alumina was calculated from a surface area determination. Prior diffusion studies on small compacts pressed from mixtures of nickel and molybdenum powders with and without 7.5 vol pct A1203 indicated that diffusion was complete after sintering for 100 hr at 1800" , or 50 hr at 2250", or 20 hr at 2550° F. The progress of diffusion was followed by microstructural examination and micro-hardness measurements. Two observations made during the diffusion experiments were: 1) That diffusion proceeded faster in the presence of alumina, confirming similar findings by Seith and Loepman on "SAP'';4 2) That diffusion at temperatures above 1800°F resulted in coarsening of the alumina in agreement with results of other authors reporting on the growth of alumina in nickel above 1800"F. Similar experiments in the Ni-Cr system using 6 and 20 p Cr powders of 0.7 and 0.025 pct 0, respectively, did not result in significant solid solution formation even after long time exposures at 2550° F. It must be concluded that chromium oxide films around individual particles interfere with normal diffusion. A nickel alloy containing 5 wt pct Mo and 7.5 vol pct alumina was fabricated by dry mixing of powders, isostatically compacting at 30,000 psi, diffusing for 120 hr in dry hydrogen at 1800" F, and extruding at 1950"~ with a 30 to 1 reduction of area ratio. The resulting structure, presented in Fig. 1

Jan 1, 1963

By Hans W. Schreiber, David W. Neuhaus

INTRODUCTION The Sunshine Mining Company's 16-to-1 silver deposit and mine project are located 384 kilometers (240 miles) southeast of Reno and 360 kilometers (225 miles northwest of Las Vegas, near Silver Peak in Esmeralda County, Nevada, at an elevation of about 2,300 meters (7,000 feet). The deposit was being developed, in 1980, with an anticipated mining and milling rate of 150,000 tons per year (500 tons per day). Mining is by underground, blast-hole open stoping with rubber-tire haul-age out of the mine to a straight cyanide plant about 5.5 kilometers (3.5 miles) from the mine. The product is a gold-silver dore which may be further refined at Sunshine's new refinery in Kellogg, Idaho. The cash required for investment was obtained through the sale of $25 million worth of 6 l/2h silver-indexed bonds. Some $15.0 million were directed toward development of the 16-to-1 Mine. These bonds, which were underwritten by Drexel Burnham Lambert of Chicago in April of 1980, are redeemable on or after April 15, 1985 or payable at maturity on April 15, 1995 at the greater of either $1,000 or the market price of 50 ounces of silver. Behre Dolbear acknowledges the kindness of the Sunshine Mining Company (Sunshine) for allowing the presentation of the subject material for this Case Study. APPLICABILITY AS CASE STUDY Reasons for Choosing 16-to-1 The reasons for choosing the 16-to-1 Mine as a case study follow: 1. The project is simple and compact. 2. The mine is small -- thus relevant to other contemplated precious metal operaions in the western states. 3. The areas of risk are readily identifiable. 4. A change to project financing was under consideration. 5. A substantial decline in the price of silver was experienced during development. 6. Behre Dolbear undertook one of the first feasibility studies of The 16-to-1 and thus has some familiarity with the project. Historical Summary The following history serves as a setting: 1. Late 1920s -- minor "production"(?) via shallow pitting. 2. Mid-1930s -- neighboring Nivlok Mine successfully put into production. 3. Late 1950s (?) -- Callahan Mining Company acquired rights and drilled -- results inconclusive; Callahan turned property back to Arthur Baker, who had originally interested Callahan in 16-to-1 on the basis of its similarity with Nivlok Mine.

Jan 1, 1985

By J. Spotts McDowell

Preparation and Use.-Magnesite is an important refractory in open-hearth, heating, and electric furnaces for steel-making and in many of those employed in the metallurgy of copper and lead. It is sold in the form of brick, finely ground "furnace magnesite" for brick-laying, and dead-burned grains for making and repairing furnace bottoms. The latter are a mixture of granules varying in size from pieces of about 5/8 in. (1.6 cm.) diameter to very fine but sandy particles. Dead-burned magnesite results from calcining 'the crude or lightly burned mineral at a temperature that will not merely drive off practically all the CO2, but will also cause sintering of the particles. During this process the pieces shrink considerably and become hard, dense, and inert to atmospheric moisture and C02; under-burned material, on the other hand, will hydrate on exposure to the air. A small percentage of ferric oxide seems to be necessary for the production of a satisfactory sinter; from 4.5 to 8 per cent. in the dead-burned grains is considered the most desirable amount. Dolomite has been little used for brick-making in the United States, but it is prepared for use in the granular condition calcined or "double-burned" and is the principal ingredient of several materials offered for sale under various trade names for refractory purposes. Dolomitic refractories are almost wholly confined to the open-hearth and electric furnaces, where they are used for fettling and as substitutes for magnesite. Much more magnesite and dolomite are used for basic open-hearth steel-making than for all other refractory purposes. The hearth of the furnace is usually built up of magnesite brick and dead-burned grain magnesite so laid that the brick base is protected by a working bottom of the granular material. The latter is sintered into place in layers 1 to 2 in. (2.5 to 5 cm.) thick to a total depth of 12 to 18 in. (30 to 45 cm.) at the center of the furnace. After each heat, burned dolomite is thrown against the banks as high as it will stick, and all holes in the bottom are filled. At most plants such holes, at the end of each week, are also

Jan 2, 1919

By P. W. Davies, B. Wilshire

PREVIOUS investigations on the effect of stress changes on the high-temperature creep and fracture behavior of metals have been confined mainly to the testing of complex alloys.172 Most of these alloys are structurally unstable during creep because of such effects as recrystallization, overaging, and so forth, so that the results are of limited application. The only pure metals on which observations have been made appear to be lead3,4 and aluminum5 tested under conditions which allow rapid recovery to take place. The present work describes the effect of a single stress change on the creep and fracture properties of a metal in which recovery is very slow. A Ni 0.1 at. pct Pd alloy was used so that grain growth and recrystallization did not occur during creep testing. Specimens of this material were heat-treated to give a uniform grain size of 10 grains per mm. Creep tests were carried out at 500°C using Denison T.47 machines; details of the creep-testing procedure have been given elsewhere.' All specimens were tested at a constant initial stress of 5 tpsi which gives, in an uninterrupted test, a minimum creep rate of ~10-3 pct per rnin and a life of -7000 min. Specimens were loaded under these standard conditions and after 1500 min, when secondary creep was well-established, the stress was changed to either 8, 7, 6, 4, 2, or 0 tpsi for a period of 180 min. After this time the original load was reapplied and the tests continued to fracture. The results are shown in Fig. 1. No detectable creep occurred during the period of reduced load, even at 4 tpsi, and on reverting to 5 tpsi the creep rate returned to its original value immediately. Increasing the stress to 8, 7, or 6 tpsi resulted in an instantaneous extension followed by a period of transient creep leading to a new steady creep rate. On returning from these higher stresses, the resulting creep rate at 5 tpsi was very low compared with the original value. Furthermore, the higher the stress during the stress change, the lower was the final creep rate. It is significant that the rupture life is comparatively unaffected by any of these stress changes.

Jan 1, 1965

Discussion of the paper of Edward Keller, presented at the Butte meeting, August, 1913, and printed in Bulletin No. 80, August, 1913, pp. 2093 to 2115. GEORGE L. HEATH, Hubbell, Mich.:-In the admirable paper quoted, is mentioned the date when the 5-g. assay was first proposed is a standard for refined metal. The author omitted, however, to mention a later paper,1 which contains a proposal for the use of a single " stock solution " of mixed acids, which has been adopted by the American Brass Co. and others. The suggestion is made that such a scheme would save time and manipulation with converter metal. Unless the low current of 0.5 ampere and the large excess of nitric acid, recommended by Mr. Keller, have been proved necessary to hold up antimony-and selenium, the use of the mixed solution which we have adopted will permit the use of 1 ampere of current per square decimeter of cathode surface, until the solutions have become colorless. At this point, we wash the covers and reduce to 0.5 ampere to prevent oxidation or contamination. The ordinary split electrodes have been used. With strong current, at least, the use of an excess of nitric acid tends to the neutralization of the solution before the end of the period, from the formation of too much ammonia., and this is detrimental. Antimony deposits more easily than arsenic, and tends to drag the latter dorm with it. There must, be some such explanation for the fact. that we have made hundreds of deposits of pure cathodes from Lake material containing no antimony, but as. high as 0.5 per cent. of arsenic. By placing an assay beaker in the Frary solenoid, or rotary device, a cathode deposit with less than 0.01 per cent. of impurity is easily obtained in one operation from 3 g. of whitneyite, carrying from 7 to 10 per cent. of arsenic. In such a case, it is necessary to test several times for end point and remove the plate as soon as no brown tint appears (at once) when hydrogen sulphide water is added to the test portion on the spot plate. Edward Keller's proportion,, of solvent figure out as 14 cc. of strong nitric to 11.4 cc. of sulphuric acid (1.84).

Jan 11, 1913

By K. R. Garr, D. Kramer, A. G. Pard

EXPOSURE of steels to a fast-neutron flux results in helium generation by (n,a) reactions. The elements Fe, Ni, Cr, and N are major participants in the (n,a) reaction and helium concentrations of up to 5 x 10"5 atom fraction could accrue in fuel clads after a year of service in proposed fast reactors.' Such concentrations of helium can severely reduce the ductility of alloys at temperatures of reactor service. The phenomenon of helium embrittlement has been studied in austenitic alloys which were irradiated with particles as a rapid means of producing significant helium concentrations.2-5 The pres-ent work is a continuation of those studies and is concerned with helium effects in a ferritic stainless steel. I) EXPERIMENT Small sheet tensile samples with a gage length of 0.50 in. and a cross-section of 0.009 by 0.040 in. in the gage length were punched from cold-rolled type 405 stainless steel. The composition of the steel used in this work is given in Table I. Prior to helium injection, the samples were annealed 24 hr at 760°C which caused complete recrys-tallization with a resulting grain size of 40 u. This treatment rendered the alloy completely ferritic and carbide particles, 0.5 to 2 uin size, were present at a density of 1 x 1011 cm-3, Fig. 1. These carbide particles were probably a mixture of the M7C3 and M4C types.6 Helium was injected into the samples by irradiation with a particles from a cyclotron, which produced uniform concentrations through the center two-thirds of the sample thickness. Details of this procedure were previously described.' The average helium concentration, as measured on a gas-source mass spec- 11) RESULTS A) Tensile Tests. The results of the tensile tests are given in Table I1 where the values shown are averages of two samples. There was no significant effect of helium on either the yield strength or tensile strength at 550" or 650°C but an increase in both is apparent at 750°C. Samples with helium showed a 20 pct loss in total elongation at 650°C which increased to a 55 pct loss at 750°C. The uniform elongation is not affected by helium at 550" or 650°C but shows an increase at 750°C.

Jan 1, 1970

By George S. Rice

MECHANIZATION in coal mining is a phrase which has attracted world-wide attention, and those persons not engaged on the practical side of coal-mine operations seem to regard mechanization as a panacea for many difficulties of the industry. The term "mechanization" as now employed by experienced mining men is restricted to mean mechanical loading of coal at the face. In a broader sense mechanization in coal mining was begun nearly half a century ago with the introduction of compressed-air undercutting machines and locomotives and, later, of electrically operated locomotives, undercutting and shearing machines, and drills. The use of coal-cutting machines, which has increased until now about three- fourths of the bituminous coal produced is being mechanically cut, first displaced hand-picking except in a few long-wall mines, and later gradually displaced the dangerous and coal-smashing method of blasting-off- the-solid.

Jan 1, 1929

By AIME AIME

THE Institute of Metals held a well rounded out symposium on the working of metals, distributed over two sessions. At the first session* four papers were presented, two dealing with the, cold working of metals and alloys and two with the hot working of non-ferrous alloys. The first paper by E. V. Crane, dealt with "Metal Working in Power Presses." Mr. Crane pointed out the empirical nature of engineering data available for use in calculating the probable stresses developed and power requirements, for the shearing, drawing, binding and other forming operations. He described the various operations, methods of determining stresses developed and presented data obtained. In the discussion C. F. Hammond took exception to Mr. Crane's objections to the rather too frequent. annealing operations in drawing of cartridge cases, pointing out that the material was-manufactured to meet specified structure and physical requirements, which could only be met by carefully controlled sequences of working and intermediate annealing operations.

Jan 1, 1931

By John M. Lovejoy

CURRENT production of petroleum on such a vast scale presents many interesting problems- the solutions of which are important not only to those directly interested in the business, but to the nation as a whole. The industry is relatively young. Until the discovers of the Lucas gusher at Spindletop in 1901 petroleum production had not exceeded 60,000,000 bbl. per year compared with 1,100,000,000 bbl. in 1936. In 36 years then, the modern oil business, production, transportation, refining, and marketing has developed. I will first present a brief history. of oil production as a background for consideration of the present situation.

Jan 1, 1937

By A. C. Fieldner

IN the Wall Street journal for March 1, 1941, was a tabulation of the construction under way or under negotiation by thirteen iron and steel companies for a predicted increase in annual coke production of 3,165,600 tons. That even this figure was short of the mark is indicated by other plans, then being considered, for a later expansion of 2,610,000 tons additional. Considerable progress has already been made on thin program, for approximately 500 new ovens were put in operation in 1941. and well over 200 should be completed in 1942. These figures include a number of units that replace older and obsolete equipment.

Jan 1, 1942