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By H. C., Weed

THE Inspiration Consolidated Copper Co., located in the Globe-Miami district at Inspiration, Ariz., became a producer of copper in 1915. From 1915 until 1948, 116,278,000 tons of ore were produced from underground workings by the block-caving system of mining. In April 1948, open-pit ore production from portions of the ore body was started and earlier plans for block-caving in these areas were abandoned. The change was due to economic conditions. Prior to the war years Inspiration's costs of mining by block-caving methods were comparable to, or even below, the costs of some open-pit operations. By the end of the war these conditions were completely changed. Underground costs had risen steadily for labor and supplies. Difficulty was being experienced in finding competent underground men and underground development was almost hopelessly behind schedule. On the other hand, open-pit costs had been sharply reduced through the development of modern earth-moving machinery and plenty of labor was available for surface work.

Jan 1, 1950

By J. Fred, Johnson

THIS TALK is a digest of some of the information contained in tables, one on practices and one on costs of shaft sinking, in Bulletin 357 of the U. S. Bureau of Mines written by E. D. Gardner, Supervising Engineer of the Bureau at Tucson, and myself. The table of practices contains information on 43 shafts and the table of costs contains information on 25 shafts. These various shafts were sunk between 1917 and 1930 so they may be termed modern practice with costs applicable in the United States, Canada and Mexico. In the compilation of this material the statistics on shafts which were concreted have been eliminated, as these figures were entirely out of line with corresponding figures for timbered shafts. It is my experience that where costs are divided between sinking and concreting the tendency is to load the costs onto the larger item of concreting. Thus a shifting of costs making an addition of 10 per cent in concreting costs may suffice to make a deduction of 40 per cent in sinking costs. Fine work is done (on the books) and everybody is happy. Most shafts are sunk with three shifts of men per day. Each shift consists of men who are miners, muckers, or timbermen, as chance may call for during their shift. Where pumping or high fixed costs do not necessitate three shifts it is cheaper to sink on two shifts. It is desirable for speed and economy in any case to work out a cycle of operations for each 24 hours. In this way men are hired for their ability as machinemen, muckers, or timbermen; they know exactly what to do and there is no passing the buck to the next shift.

Jan 1, 1933

By P. Marier, T. R. Ingraham

When cylindrical powder compacts of nickelous oxide (NiO) are heated in an equilibrated stream of SO3, SO,, and 02, in the temperature range 500°to 800°c, tlickelous suljate (NiSO4) is formed as an adherent layer on the oxide. The reaction is diffusion-controlled, with an activation energy of 13 ± 3 kcal per mole. When cylindrical powder compacts of NiSO4 are heated in a stream of dry nitrogen in the temperature range 1000 0to 11500C, NiO is formed at a well-defined interface between the sulfate and oxide. The interjhce migrates into the sulfate at a constant rate at a constant temperature and gas flow. The reaction rate increases with increasing gas flow and decreases with increasing partial pressure of SO3 in the gas stream. Resolution of the partial-pressure data with a Lang-itzliir Adsorption Isothern suggests that about 80 pct of the NiO interface is covered with SO3. The heat of adsovption is about 68 kcal per mole. The activation energy of the decomposition process is 61 ± 3 kcal per mole. MOST of the work reported on the formation and decomposition of nickel sulfate is related to thermodynamics.1-3 No quantitative work has been reported on the decomposition process. The only kinetic work reported on the formation is that by Fletcher and shelef.4-6 whose main purpose was to study the effects of alkali metal sulfate additions on increasing the rate of nickel sulfate formation. They found that, in the absence of an additive, only small amounts of sulfate were formed and the kinetic data were difficult to interpret. However, they suggested that the sulfa-tion of nickel oxide is a diffusion-controlled process for which the activation energy is approximately 17 kcal per mole.6 In this paper, both the formation and decomposition reactions will be examined; and based on the effects of temperature, flow rate, interfacial area, and partial-pressure of sulfur trioxide, mechanisms and activation energies will be suggested for both processes. EXPERIMENTAL Material. The nickel source material used in all experiments was Baker and Adamson Reagent Grade NiSO4. 6H2O, for which the following analysis was supplied by the manufacturer: C1, 0.001 pct; NO3, 0.005 pct; Co, 0.02 pct; Cu, 0.005 pct; Pb, 0.002 pct; Fe, 0.001 pct: insol, 0.005 pct. The anhydrous sulfate was prepared by heating the hydrate at 420°C in a muffle furnace for 5 hr. Nickel oxide was prepared by decomposing the sulfate at 950°C over a period of 10 hr. Method. The technique used for measuring the rates of formation and decomposition was developed earlier in these laboratories.7-8 The method is based on the observation that the kinetic parameters of a reaction can be established in a flow system, with specimens prepared by compacting powder to a uniform pellet shape. The results are identical with those established with solid polycrystalline specimens or single

Jan 1, 1967

By J. P. Heller, H. B. Bradley, A. S. Odeh

A potentiometric model technique is presented for determining the areal sweep efficiency of a five-spot well pattern, at and beyond breakthrough. A sharp interface between displaced and displacing fluids is assumed. Although the prototype svstem is referred to as a waterflood operation, obvious changes in the notation and computations will adapt the results to other displacement processes. The results of the study include the following. 1. Areal sweep efficiencies for a five-spot well pattern, at and beyond breakthrough, for mobility ratios (displacing to displaced fluid) of 4:1, 2:1, 1:1 and 1:4. 2. Extension of potentiometric analysis to the investigation of the areal sweep efficiency beyond breakthrough in a five-spot pattern by the application of conformal mapping and conductive-solid models. 3. The use of layers of conductive fabric in representing mobility ratio changes in potentiometric models. 4. The development of a probe mechanism for probing conductive solids. The results obtained by conductive-cloth models agree with earlier areal sweep efficiencies at breakthrough obtained by Aronofsky and Ramey 1 on the potentiometric analyzer using electrolytic-tank models. Results beyond breakthrough differ from those obtained by the X-Ray Shadowgraph technique. Data from this study show that, for mobility ratios greater than one, water cut rises rapidly as fluid is produced after breakthrough. However, for mobility ratios smaller than one, a large increase in area swept resulted with only a small increase in water cut. INTRODUCTION In calculating reservoir performance of waterflood-ing operations and other fluid-injection programs, it is necesssary to estimate the areal sweep efficiency * before and after injected-fluid breakthrough into production wells. Influence of mobility ratio on oil-production history, before and after breakthrough for a five-spot well pattern, has been studied by X-Ray Shadowgraph techniques 2-5 and by gelatin models.6 In none of these investigations was the transition zone controlled experimentally. Steady-state anaiog techniques assume that a vertical and discrete interface exists between the displacing and displaced phase. Thus, when using a potentiometric analysis, it is assumed that no transition zone exists. To determine the areal sweep efficiency beyond breakthrough for a five-spot well pattern using the potentiometric analyzer, four principal problems had to be resolved. These were the following. 1. The laborious method of representing changes in mobility ratio in electrolytic tanks by means of contoured wooden blocks. 2. Vapcrization of the electrolyte solution during the study causing concentration changes and, thereby, variable conductivity. 3. The scale-limitation problem 7 that is accentuated by abrupt eiectrolyte depth changes. 4. A wellbore geometry problem. EXPERIhlENTAL EQUIPMENT AND PROCEDURES CONDUCTIVE-SOLID MODEL The theory, equipment and procedural techniques of the electrolytic-tank potentiometric model have been treaced excellently by Lee8 and by Muskat.9 By the use of a conductive solid to represent the fluid conductivity of the porous media, the need for contouring wooden blocks to represent mobility ratio was eliminated. It was found that a carbon-black coated fabric, Uskon D-16,** could be employed as a fairly uniform conductive media. This material, when stacked in appropriate layers and pressed together, can be used to represent changes in mo-

By Ervin E. Underwood

IT has been recognized for many years that dis-persed particles have great value in raising the creep resistance of metallic alloys. In fact, some of the most successful high-temperature alloys owe their superiority to this factor above all others. A recent observation by Glen1," indicates that even better high-temperature resistance to deformation results in alloys capable of two successive precipitation reactions. The ramifications of this finding are of great interest. Unfortunately, our understanding of the reasons for such notable improvements has not kept pace with technical developments. In an effort to uncover some of the basic facts governing strengthening by particles, a program was initiated at the Battelle Memorial Institute with the primary goal of comparing creep strengths in single-phase and two-phase (precipitating) alloys. The effects of precipitation from solid solution on the creep properties of alloys are generally such that the resistance to creep is increased. However, if alloys are heat treated to different degrees of hardness before creep testing, it is often found that those possessing the maximum hardness initially do not necessarily have the maximum creep resistance. Depending on the stresses and temperatures involved other structures may prove more desirable. Considerations of the above nature indicate the importance of defining the initial state of the alloy. Here, it was decided to start with quenched single- phase alloys in which precipitation and creep deformation proceed concurrently. Equipment and Experimental Procedures Preparation of the Specimens—Four 25 lb ingots were prepared from 99.999 pct Cu and 99.996 pct Al to compositions of 1, 2, 3, and 4 wt pct Cu. Spec-trographic and chemical analyses are listed in Table I. After heat treatments and intermediate reductions, the alloys were cold rolled to 1/8 in. thick sheet. The final cold reductions amounted to 50, 40, 20, and 10 pct for the 1, 2, 3, and 4 pct Cu alloys, respectively. The specimens for creep testing were machined into tensile flats 7 in. long, 3/4 in. wide (at the shoulders), and 1/8 in. thick. The reduced sections were 1/4 in. wide and 21/2 in. long. After heat treatments at 540°C to an ASTM grain size of 1 1, the specimens were quenched into water at room temperature, then electropolished in a glacial acetic acid and perchloric acid solution. The gage marks were Knoop impressions placed 2 in. apart on the reduced sections. Blanks of 1 x 1 in, were cut from the same sheets for the age hardening runs and were given the same grain size heat treatments. The specimens and blanks were stored in a refrigerator at —40°C until needed for testing. Creep Measurements—Creep tests were conducted in a constant temperature room which was maintained at 26° ±1°C. A split-type, hinged, vertical-tube furnace was mounted on a horizontal track so that the specimen could be enclosed suddenly. Thus, it took about 15 min for the specimen to come within 5°C of the test temperature. The temperature variation along the specimen was controlled to about

Jan 1, 1958

By Orville R. Lyons, A. C. Richardson

THE Coal Division of Battelle Memorial Institute, during the course of an investigation conducted for a coal producer, carried out extensive sampling of the fine-coal section of a preparation plant. The information obtained during the testing period was used to evaluate the overall plant operation and provided the basis for. recommended changes in the plant flowsheet. Included in the information were data for the results obtained when using a Bird centrifuge to dewater the particular coal being treated. At the completion of the investigation, the coal producer gave Battelle permission to publish the operating data for the Bird centrifuge in order to make this information available to the coal industry. The authors wish to take this opportunity to express their appreciation to this company and its officials for their willing cooperation in the matter of publication. Description of Preparation Plant: The preparation plant on which the data were obtained is primarily a jig plant. The coal being washed is a low inherent moisture, friable, Pocahontus-type. The washed coal from the jig is dewatered and sized at 1/4 in. by a Parrish-type dewatering and sizing screen. The minus 1/4-in. coal and the underflow water from the shaker screen flow to a sludge tank where, after the coal settles, the coal is conveyed by a flight conveyor into a pump sump. The pump, a 300-gpm sand pump, delivers a mixture of fine coal and water to a Bird centrifuge which produces a dewatered cake and an effluent. At the time when the investigation was made, the centrifuge effluent was returned to the sludge tank and the cake product was mixed with a coarser size of coal prior to loading into railroad cars. The semiclarified water from the sludge tank overflowed into a pump sump from which it was pumped to the jig. As originally designed, the preparation plant was intended to operate with a closed water system but it was found, soon after operations started, that for various reasons this could not be done. In order to provide for removal of excess water from the system and to aid in maintaining the desired minimum percentage of solids in the circulating water, the plant was operated to provide from the sludge tank a continuous overflow of water and fine solids that was sent to waste. The centrifuge feed represents approximately 35 tons per hour of minus 1/4-in. coal in the form of a pulp averaging 38 pct solids. Sampling Procedure: In order to obtain basic data for determining the relationships existing in the fine-coal section of the preparation plant, samples were obtained for: (1) the centrifuge feed, (2) the centrifuge cake, (3) the centrifuge effluent, and (4) the circulating water. The sampling was arranged to start on a Monday, in order to begin operations with a sludge tank full of fresh water, and was continued long enough to allow sufficient time for fine solids to build up within the water system or for a two-day, four-shift operating period. All samples were taken at half-hour intervals except when plant stoppages occurred. After a stoppage the plant was

Jan 1, 1951

By T. D. Tiemann

The extraction of iron oxide from several types of siliceous iron ore by digestion in sulfuric acid solutions was investigated in the temperature range from 80 to 258°F at concentrations from 10-60% H2SO4. Degree and rate of extraction were found to be critical with respect to both temperature and acid concentration, requiring temperatures in excess of 250° F and acid concentrations of 50% to effect 80-90% extraction of iron oxide in 60 min. Rate of extraction is directly related to surface area and apparently controlled by the rate of chemical reaction. The activation energy was found to be approximately 25,000 cal per g mol. Extraction characteristics of the several ores were found to be similar. The Department of Minerals and Metals Engineering at the University of Wisconsin conducts a continuing research program to develop processes for the utilization of low-grade iron ore deposits such as the nonmagnetic taconites of the Wisconsin Gogebic range. Methods under study include high-intensity magnetic and high-tension electrical concentration, flotation, direct reduction and chemical extraction. Concentration of a number of low-grade siliceous iron ores by the extraction of silica in sodium hydroxide solutions has been reported by the writer and others in the literature.1,2,3,4 Residual concentrates containing as much as 65% iron have been obtained from taconites containing less than 30%. Currently an alternative approach is under study, namely the dissolution of iron oxides from siliceous gangue by extraction in acid, with subsequent recovery of the iron from solution. Such a process for extracting iron oxide from the low-grade oclitic deposits of Alberta with hydrochloric acid was investigated and described by Gravenor, Govett and Rigg.5 The current investigation, which is entirely devoted to extraction with sulfuric acid, is the subject of this paper. In part, the objective of this research was to determine the possibility of leaching iron ores in situ with sulfuric acid. The investigation of a recovery method is left to later research. The ores investigated contained hematite (Fe2O3) as the principal iron-bearing mineral and minor amounts of goethite (Fe2O3 .H2O), magnetite (Fe3O4), and iron-bearing silicates. The gangue was essentially quartz occurring as single crystals and microcrystalline aggregates. Detailed description of the ores may be found in the literature.1,2,4,6 A comparison of the specific ores used in this investigation is shown in the partial analyses of Table I. EXPERIMENTAL METHODS All extractions were made at atmospheric pressure using beakers with a mechanical stirrer for those tests run below the boiling point, and Erlenmeyer flasks for those at the boiling point. A thermostatically controlled hot plate was used for heating, and this maintained the mean temperature within the solution to within ±3°F during extraction. The sample of ore for extraction was weighed to + 0.02 g. For tests below the boiling point, the sample was added to the beaker containing the sulfuric acid solution at the desired temperature. For the boiling-point tests, the sample was added to the Erlenmeyer flask followed by distilled water and the

Jan 1, 1968

By Orville R. Lyons, A. C. Richardson

THE Coal Division of Battelle Memorial Institute, during the course of an investigation conducted for a coal producer, carried out extensive sampling of the fine-coal section of a preparation plant. The information obtained during the testing period was used to evaluate the overall plant operation and provided the basis for. recommended changes in the plant flowsheet. Included in the information were data for the results obtained when using a Bird centrifuge to dewater the particular coal being treated. At the completion of the investigation, the coal producer gave Battelle permission to publish the operating data for the Bird centrifuge in order to make this information available to the coal industry. The authors wish to take this opportunity to express their appreciation to this company and its officials for their willing cooperation in the matter of publication. Description of Preparation Plant: The preparation plant on which the data were obtained is primarily a jig plant. The coal being washed is a low inherent moisture, friable, Pocahontus-type. The washed coal from the jig is dewatered and sized at 1/4 in. by a Parrish-type dewatering and sizing screen. The minus 1/4-in. coal and the underflow water from the shaker screen flow to a sludge tank where, after the coal settles, the coal is conveyed by a flight conveyor into a pump sump. The pump, a 300-gpm sand pump, delivers a mixture of fine coal and water to a Bird centrifuge which produces a dewatered cake and an effluent. At the time when the investigation was made, the centrifuge effluent was returned to the sludge tank and the cake product was mixed with a coarser size of coal prior to loading into railroad cars. The semiclarified water from the sludge tank overflowed into a pump sump from which it was pumped to the jig. As originally designed, the preparation plant was intended to operate with a closed water system but it was found, soon after operations started, that for various reasons this could not be done. In order to provide for removal of excess water from the system and to aid in maintaining the desired minimum percentage of solids in the circulating water, the plant was operated to provide from the sludge tank a continuous overflow of water and fine solids that was sent to waste. The centrifuge feed represents approximately 35 tons per hour of minus 1/4-in. coal in the form of a pulp averaging 38 pct solids. Sampling Procedure: In order to obtain basic data for determining the relationships existing in the fine-coal section of the preparation plant, samples were obtained for: (1) the centrifuge feed, (2) the centrifuge cake, (3) the centrifuge effluent, and (4) the circulating water. The sampling was arranged to start on a Monday, in order to begin operations with a sludge tank full of fresh water, and was continued long enough to allow sufficient time for fine solids to build up within the water system or for a two-day, four-shift operating period. All samples were taken at half-hour intervals except when plant stoppages occurred. After a stoppage the plant was

Jan 1, 1951

By D. F. Kaufman, E. D. Levine, L. R. Aronin

ThE primary slip plane in hcp metal crystals can usually be inferred from the c/a ratio. Basal slip is the primary system at room temperature for zinc, cadmium, magnesium, cobalt, and rhenium, all of which have a c/a ratio greater than 1.60. Zirconium and titanium, on the other hand, each with a c/a ratio of 1.59, deform primarily by (1010) [ll20] prismatic slip. The increasing tendency toward prismatic slip in these materials is generally thought to be associated with the increase in atomic density on (10i0) as c/a is reduced. Beryllium, with a c/a ratio of 1.57, would, according to the above scheme, be expected to exhibit prismatic slip. However, in beryllium of commercial purity, the primary deformation mode at room temperature is basal slip.' The ratio of critical shear stress for prismatic to that for basal slip at room temperature is approximately 5:l. The critical shear stress for prismatic slip decreases quite rapidly with increasing temperature, however, and at 500°C the ratio is approximately unity. The apparently anomalous behavior of beryllium has led to speculation that prismatic slip in this material may be restricted by an anisotropic effect of impurities,' and that, if beryllium could be purified to a sufficient extent, prismatic slip might predominate at room temperature. In such a case, the conditions under which basal cleavage can occur would be suppressed, and enhanced low-temperature ductility might result. With the advent of the floating-zone method for purification of beryllium,3 it has become possible to determine experimentally the effects of purification on basal and prismatic slip. Tensile tests were performed at room temperature on single crystals oriented favorably either for basal or prismatic slip. The crystals had been purified to various extents by zone-refining, employing procedures that have been described elsewhere.4 Relative purities of the crystals were estimated by measuring the ratio of electrical resistance at 4.2"K to that at 298°K. Typical values ranged from 0.40 for commercial-purity material to 7.7 X 10"4 for crystals prepared from vacuum-distilled beryllium and subjected to six zone-refining passes. The purity dependence of the critical shear stresses for basal and prismatic slip is shown in Fig. 1. In the purity range studied, the critical shear stress for basal slip is decreased from 1.4 to 0.14 kg per sq mm. The critical shear stress for prismatic slip is decreased from 6.7 to 5.3 kg per sq mm. The decreases in critical shear stress for each deformation mode, therefore, are approximately equivalent. No purification anisotropy is observed. Because of the absolute magnitudes of the critical stresses, the ratio of the critical shear stress for prismatic slip to that for basal slip actually increases from 5:l to 38:l at the highest purity level studied. It is evident, therefore, that basal slip is the primary deformation mode in high-purity beryllium. This fact must be accounted for in any rationalization of the deformation behavior of hcp metals. This work was performed at Nuclear Metals, Inc., under the sponsorship of the U.S. Atomic Energy Commission.

Jan 1, 1964

By J. Murray Riddell

The method of treating hazards wherein value is decreased, is cited by R. D. Parks. Quite properly, the theory of probabilities is made use of when multiple hazards are under consideration. E. F. Fitzhugh, Jr. $ deals with the enhancement phase graphically and uses percentage of expectancy as derived by a study of conditions and the selection of a chance factor. It is believed that both of the authors referred to fully recognize the part which human judgment plays, and as coupled with experience, training, and the application of the theory of probabilities; in that respect the composer of this paper is in accord. Within the past year, the task of arriving at a mathematical method for handling the enhancement phase, and, additionally, coupling the negative and positive phases, was explored. In citing the hazard, or negative phase, reference is made to the text by Parks. Types of Items far Consideration On the hazard, or negative, side some of the common items to be considered are: 1. Subsidence and resulting damage. 2. Flo wage of water above that anticipated. 3. Geological. (a) Decline in quality of probable ore, and/or (b) Decline in quantity of probable ore. 4. Depressed economic conditions. 5. Litigation. Similarly, on the enhancement, or positive, side common items to be considered are: 1. Flo wage of water below that estimated. 2. Geological. (a) Increase in quality of probable ore, and/or (b) Increase in quantity of probable ore. 3. Elevated economic conditions. 4. Litigation. 5. Technological advance in the art. Tn all of the above items no consideration is given to placing a value on, or giving consideration to, possibilities. For example, referring to Table 1, the estimated normal present value (Vp) of a property, exclusive of risk consideration, is taken as $100,000. If subsidence affects the usefulness of the shaft, the present value of the property will decrease to $60,000, and it is judged that there is a 1 in 4 chance that the shaft will be impaired;, consequent.ly, if subsidence took place, the present value would be reduced ($100,000-$60,000) $40,000, but since the chance is 1 in 4, the allowable reduction would be only one-fourth of $40,000, or $10,000, or a discount of 10 pct (hazard factor) of the original value; the related safety factor is taken as unity minus 0.10, or 0.90. Thus, the original Vp, $100,000, multiplied by the safety factor ($100,000 X 0.90) gives $90,000, which is the adjusted present value of the property in this single instance. Additionally, there is a water hazard, which, if encountered, will reduce the present value to $85,000. The chance is 1 in 3. Following through with the same reasoning as shown above, the derived safety factor will be 0.95. To arrive at a single multiplying factor which will express the combined risks, the two safety factors are multiplied together, 0.90 X 0.95 = 0.855. That factor when multiplied by the origirial Vp will give the adjusted, and

Jan 1, 1950

By Harry E. Krumlauf

The year 1957 was one of declining metal price and production. Many lead-zinc-copper mines were forced to close, and the remaining mines limited production to stay more in line with demand. High cost of labor, supplies, and equipment and high taxes aggravated the situation. Some operators postponed or abandoned expansion programs because of uncertain economic conditions. Output was curtailed by elimination of over- time employment and reduction of the working force. The number of employes laid off was small- reduction in the labor force was accomplished by not replacing those who left a company's employ.

Jan 2, 1958

By Zárate G. E.

Practical and statistical considerations concerned with the sampling, sample preparation and chemical analysis of precious metal ores are reviewed. The principal requirements related with the characteristics of sample cutter, sample preparation, equipment and methods are discussed. The main errors introduced in the different stages of the sampling systems are defined. The application of statistical techniques to evaluate these errors to determine the ore grade variation and to design the number of increments needed to get an accurate assay are presented. Finally, results obtained with the application of this method to gold and silver ores are analyzed and some recommendations are given.

Jan 1, 1984

By M. R. Geer

Coal washing assumed an important role in the mining industry of the Pacific Northwest long before washing practice became firmly established in the Appalachian field. A Scaife washer was operated in the state of Washington in 1887; and by 1927, the fist year for which complete statistics were compiled, nearly a third of the state's coal production was washed, in comparison with only about 5 pct for the country as a whole. Mechanical preparation was adopted in Alaska in 1922 in a plant constructed by the United States Navy at Chickaloon to provide bunker coal for naval forces operating in northern waters. Many of the coal beds mined in Washington and Alaska contained more impurities than those mined elsewhere, and this circumstance contributed to the early interest in mechanical cleaning. A much more important factor, however, was the inclination of the coal beds. With steeply pitching beds, hand sorting by the miner at the face is impossible; consequently, all material must be loaded and dealt with on the surface, just as is now proving the case with mechanical mining of flat beds. Thus "full-seam" mining afforded the same stimulus to the early development of coal washing in the Northwest that - it is providing under mechanization in the rest of the country today.

Jan 1, 1949

All the TECHNICAL PUBLICATIONS and CONTRIBUTIONS published in 1940 are available at Institute headquarters, unless otherwise noted. They are also on file in many public, university and technical libraries and, when so indicated in the list, may be found in the TRANSACTIONS. TECHNICAL PUBLICATIONS in Classes A-Metal Mining, B-Milling and Concen-tration, H-Industrial Minerals, and I-Mining Geology are distributed in MINING TECHNOLOGY, which is issued every other month. Technical Publications in Classes C-Iron and Steel Division, D-Nonferrous Metallurgy and E-Institute of Metals Division are distributed in METALS TECHNOLOGY, which is issued twice quarterly. TECHNICAL PUBLICATIONS in Class G-Petroleum Division are distributed in PETRO-LEUM TECHNOLOGY, which was issued quarterly in 1940 but will be issued every other month in 1941. TECHNICAL PUBLICATIONS in Classes F-Coal Division, J-Mineral Industry Education Division, K-Mining Administration, and L-Geophysical Methods of Exploration are issued as separate pamphlets. An Institute member is entitled to one copy of any TECHNICAL PUBLICATION or CONTRIBUTION. Copies of TECHNICAL PUBLICATIONS listed have been mailed to members of the Institute accord-ing to their registration by classes. CONTRIBUTIONS and other TECHNICAL PUBLICA-TIONS will be sent upon request. A member may purchase an additional copy of a TECHNICAL PUBLICATION or a CONTRIBUTION at one cent a page; minimum charge, 25¢. Nonmembers may purchase any CONTRIBUTION or a TECHNICAL PUBLICATION of the F, J, K, or L classes at the same rate, but the nonmember price per copy for METALS TECHNOLOGY, MINING TECHNOLOGY or PETROLEUM TECHNOLOGY is $1.25 domestic, $1.35 foreign countries. TECHNICAL PUBLICATIONS (separate pamphlet form), $2 per annum domestic, $2.50 foreign. METALS TECHNOLOGY, $7 per annum domestic, $7.80 foreign (Iron and Steel Division and Institute of Metals Division ferrous and nonferrous papers). MINING TECHNOLOGY, $6 per annum domestic, $6.60 foreign (metal mining, milling and concentration, Industrial Minerals Divi-sion, and mining geology papers.) PETROLEUM TECHNOLOGY, $6 per annum domestic, $6.60 foreign. Bound volumes have been mailed to members that have requested them, and MINING and METALLURGY is mailed each month. A member is entitled to one volume a year on his membership and he may purchase for $2.50 one copy of a volume not already received; additional copies of the same volume, $5. Nonmembers may pur-chase the volumes listed, at $5 each, plus 60 cents for Canadian or foreign postage. Extra single copies of MINING AND METALLURGY, 25¢ current issue, back numbers 50¢ each to members; to nonmembers 506 current issue and $1 each, back issues. Subscription price to nonmembers and to members for extra copies, $3 per annum domestic, $4.00 foreign.

Jan 1, 1940

By R. H. Coats

MINING occupies a position of less importance than manufacturing or agriculture in Canada, but its relative contribution has increased greatly during the post- war period. Mineral production was only 5.14 per cent of the net value I of production of all kinds of commodities in 1919, but by 1936 the pro- portion had risen steadily to 12.76 per cent. Mining felt the depression, hut unlike agriculture, which is still ' sorely stricken, it has passed from early convalescence to complete recovery. For each of the last two years new high records were established for the industry as a whole and for the quantity of most metals produced. Mining has had a notable effect on - the growth of the power industry in Canada. Water power has been developed in the same or adjacent areas wherever mining camps have been 1 established, with few exceptions. Consumption of electrical energy by the mining industry gained 72 per cent within a decade, rising from 1604 million kw.-hr. in 1926 to 2754 in 1935. In. 1935 alone the mining industry purchased electric power

Jan 1, 1937

By AIME

THE wind howls almost incessantly over the mining engineers working in the near desert that is the Division of Namaqualand, the upper Atlantic coastal corner of South Africa's Cape of Good Hope Province. But when these men at the U. S.-owned mines called Nababeep South and East O'okiep (pronounced Oh-keep) tell you about their achievements, they can be heard above the wind. For their O'okiep Copper Co. Ltd. now produces over half the Union of South Africa's annual output of 30,000 tons of copper metal. Moreover, it is a very decent sample of U. S. geotechnical imagination. financial daring, and managerial skill, all operating successfully in a

Jan 1, 1947

By Edward H. Bzirdick

THE territory under particular consideration in this article comprises portions of La Plata and Montezuma Counties, situated in the southwestern corner of Colorado, and around the base of the La Plata Mountains. (See Fig. 1.) In southeastern Utah and northeastern Arizona there are several mountain systems whose origin and structure are practically identical with the La Platas so that ore occurrences found in the latter can be hopefully looked for in the former. With this assumption, there is an area around the laccolithic ranges which offers promise for a successful exploration for gold ores. Ore occurrences of the Silverton, Telluride, Rico, or Ouray Districts will not be discussed, although in these areas the Mesozoic sediments are more or less involved within the ore-bearing complex. These have been intensively studied and developed. The idea is to set forth what my mining experience has been within the largely unaltered . Mesozoic horizon which remains around the extreme bases of the La Plazas. This, until recent years, has been almost entirely neglected by prospectors and operators and, so far as similar territory in Utah and Arizona is concerned, so remains.

Jan 1, 1934

By T. A. Read, H. K. Birnbaum

Deformation of AuCd alloys having the 8 (orthorhombic) and (3" (tetragonal) structures occurs by the stress induced motion of twin boutdaries. A restoring force acts on displaced twin boutdaries as a result of internal energy increases in the volume through which the boundaries are displaced. The phenomonology of the twin boundary motion is described and a mechanism for twin boundary motion and the restoring force is proposed. A time-dependent stabilization behavior of the twin boundaries, which is observed after the twins are formed by the diffusionless phase transformations, is described. THE AuCd 8 phase (ordered bcc structure) exhibits a transformation to a phase having an orthorhombic structure, 8' (space group D'), for compositions in the vicinity of 47.5 at. pct Cd and to a phase having a tetragonal structure, 8" (point group 4/m, m,m), for compositions in the vicinity 50.0 at. pct Cd. Both transformations are diffusionless, occur on cooling at 60" and 30OC, respectively, and are crystallo-graphically reversible.' They are accompanied by an inhomogeneous deformation which was observed to be twinning in the low-temperature phase. 3'4 The transformations may occur by a "single interface" or by "multiple interfaces."5'6 In the "single interface" transformation, the twinned product phase consisted of two twin orientations as shown in Fig. 1. In the multiple interface transformation the product phase contained "domains" each of which contained two twin orientations, Fig. 2. Deformation of specimens containing transformation twins was achieved by motion of the twin boundaries. Releasing the applied stress resulted in the displaced twin boundaries returning towards their initial positions. This "pseudo-elastic" behavior of the boundaries varied with time after the formation of the twin boundaries by the transformation.

Jan 1, 1961

By William F. Boericke

RESEARCH in the modern refractories laboratory has two practical ends in view-to develop refractory materials for the metallurgist that will meet particular operating difficulties more effectively and to ?manufacture these refractories at a cost sufficiently low to make their use economical to the metallurgist. At the research laboratories of E. J: Lavino and Co., at Plymouth Meeting, Pa., the technical staff, under Dr. Gilbert E. Seil, is giving principal attention. to an. exhaustive investigation of the following factors in refractories:

Jan 1, 1931

By WOOLSEY MCA JOHNSON

INDEPENDENTLY of the recognized chemical reactions involved in the production of metallic zinc, the process is affected by physical conditions in efficiency, and by commercial as well as technical economy. To offer some observations concerning these conditions is the purpose of the present paper. Among the important elements of this problem is the physical nature of the particles constituting the mass of zinc oxide to be reduced. This may be the result, either of the manner of the original deposition of the mineral, or of the treatment to which it has been subjected in the roasting-furnace. The physical character of the reducing-agent is another important factor, since the carbon of some coals is much more active in reduction than that of others. The degree of fineness, whether of ore or coal, or both, likewise plays a significant part. These factors, together with the physical admixture of foreign substances with the ore, may give rise also to chemical "side-reactions," sometimes hindering or retarding, and sometimes accelerating, the reduction. Finally, thermal conditions, including the relative conductivity of the materials, deserve to be taken into account. In firing a furnace with retorts charged with a mixture of roasted ore and coal, the first reaction is naturally the boiling-off of the contained water ; the next is the distillation of the light hydrocarbons from the coal; the next is the reduction of the iron oxide to protoxide and sub-oxide successively, and then to metallic sponge; and the final reaction is the reduction of the zinc oxide in the ore by the carbon to metallic zinc. This reaction commences at 1,022° to 1,060° C., according to the physical nature and condition of the coal and ore. Since the retort and the charge are far from being good con-

Sep 1, 1907