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By F. C. Blickensderfer

During 1914 and 1915, extensive experiments were conducted at the concentrator of The Detroit Copper Mining Co. of Arizona, at Morenci, Ariz., in order to test the relative grinding efficiencies of the Marathon, the Chilean and the Hardinge Mills. The Marathon mill used in the experiments was the first one ever built by the manufacturers; and since this was the first time that it was given a thorough tryout, with such remarkable results, the data have been assembled in the following paper and submitted in the interests of the milling profession. Description of the Flow Sheet The concentrator flow sheet, as it existed at the time of these tests, is shown in Fig. 1. The total mill feed, as delivered from the crushing plant, had as its maximum size 1-in. material. This material was screened dry on Cole Zig-Zag screens fitted with 4-mesh openings; the oversize going to one pair of coarse rolls, the undersize to five Wilfley tables fitted with Butchart National riffles. The coarse-roll product was elevated and screened wet on Zig-Zag screens fitted with 4-mesh openings, the undersize going to the five tables mentioned above and the oversize to one pair of fine rolls. The fine-roll product was elevated and screened together with the coarse-roll product; so that, before any concentrating operations took place, the total mill feed was reduced to pass a 4-mesh screen. After concentration on Butchart-riffled tables, the tailings from these tables passed to de-sliming hoppers, where two products were formed, viz., an overflow and a discharge. The discharge constituted the feed for the Chilean mills. It contained 16 per cent. slime (—200 mesh) and 3 parts of water to 1 of solids. The concentrator was equipped regularly with four Chilean mills (Monadnock type) to the unit; but, in order to

Jan 1, 1917

By Richard T. Newcomb

This paper considers the many problems involved in estimating rates of technical change via productivity indexes. In mining, declining ore grades complicate the measurement of progress considerably. The estimates discussed in this article were made for the United States iron mining industry by means of two techniques: a simple model of production with two inputs, and multiple regression. The results can be used to explain the relation existing on U.S. iron ranges between rates of exhaustion, technical change, output per man and the increase in capital proportions observed since World War I. Similar ob-servations can be made on the mining sector trends in the United States, Canada, and Japan. Formidable problems confront the economist attempting to estimate the influence of technological changes on the progress of mineral industries. Peculiar to these industries is the problem of how to adjust any measure of technological progress for the offsetting influence of exhaustion. Exhaustion has long been recognized in the mining industry as a critical dimension. Empirically, it is usually treated as a problem of declining grades of ore either in production or in reserves. There are studies of the trends in mining industries attempting to relate changes in input requirements to changes in grade and technology over time. Most frequently, the measure used to indicate technological progress is average labor productivity, e.g., output per man-hour. However, although such an approach has the merit of being simple and direct, it ignores the influence of other important factors of production such as capital. Without defining both the nature of technological change and of production, it can be very misleading to identify increases in labor productivity with tech-

Jan 1, 1969

By Edward W. Parker

Note.—The material from which this paper has been prepared was collected tor the U. S. Geological Suvey Bulletin, No. 316, Contributions to Economic Geology, 1906, and appears also, though in somewhat more extended form without illustrations, in that publication. Although the briquetting of coals and lignites has been carried on for many years in Europe, and has reached a particularly high state of development in France, Belgium, and Germany, it has made comparatively little progress in the United States. The causes for the backwardness of the United States in this regard are several, and first among them has been the abundant supply of cheap raw fuel with which the manufactured article has to compete. With our millions of acres of coal-productive territory, from which the product can in moat cases be cheaply extracted, it has appeared in many districts more economical to waste the slack or culm, which constitutes a considerable percentage of the product, than to attempt to save it at the additional expense required for briquetting. It is for this reason that the view in all sections -of the anthracite-region of Pennsylvania is marred by the unsightly culm-banks which encumber the ground, and that in some of the bituminous-districts one sees huge piles of unmarketable slack allowed to burn up in order to get rid of them. When the coal is of a coking quality, or when the slack can be used for steaming-purposes, these losses are not sustained, but many thousands of tons of what might be converted into usable fuel have been wasted every year simply because of the increased expense involved in its preparation.

Jan 1, 1908

By R. Dugdale, F. Habashi

Studies on hand-picked samples of chrysocolla from Arizona showed that heating in an inert atmosphere enhances greatly copper extraction by ammoniacal-ammonium carbonate solutions. Heating in hydrogen improves the extraction of copper even further and maximum extraction by ammoniacal-ammonium carbonate and by sodium cyanide solutions is achieved for samples heated at 350°C. Heating in SO2 atmosphere results in the simultaneous formation of CuSO4 and Cu2O; maximum reaction rate is also achieved at 350°C. At temperatures higher than 350°C, CuCO4 starts to decompose. Chrysocolla heated above 600°C either in argon, H2, or SO2, is rendered less amenable to leaching, supposedly due to the formation of insoluble copper silicates.

Jan 1, 1974

By AIME AIME

THE Petroleum Division will hold two meetings this fall, one on the Coast at Los Angeles, Sept. 29, with the technical sessions in the assembly room of the California Oil and Gas Association and a banquet Friday evening at the Richfield Cafe atop the Richfield building; the other in the Southwest, at Dallas, Texas, Oct. 6 and 7, with the Baker Hotel as headquarters. Dr. Frederick M. Becket, President of the Institute, and A. B. Parsons, Secretary, will attend both meetings. Arrangements for the meetings are not yet complete but the respective local committees, working in close touch with the officials of the Division are rapidly shaping up the programs and other detail.

Jan 1, 1933

By William Griffith

THE purpose of this paper is to make public record of new information in regard to the sustaining power of artificial mine-roof supports (not timber props) the result of investigations recently made in the anthracite coal fields of Pennsylvania. First.-By the "Scranton Mine Cave Commission," appointed to investigate the mining conditions under the City of Scranton. Second.-By the "Pennsylvania Mine Cave Commission," appointed by the Governor to investigate the general subject of mine caves in the anthracite region of Pennsylvania. Third.-By the personal researches and tests made by the author in an effort to secure a better artificial mine-roof or surface support. During the progress of the work of the Scranton Mine Cave Commission, the Engineers for the Commission, Messrs. Conner and. Griffith, being aware of the general lack of exact information in the engineering profession as to the strength of the ordinary artificial mine-roof or surface support, and particularly the stronger kinds, such as mine cogs, rock piers, etc., had tests made at the. Fritz Engineering Laboratory at Lehigh University, to determine the sustaining power under various compressions of the several kinds of artificial mine supports in use in the anthracite region of Pennsylvania. A report of these tests was included in the report of this Commission, which was published as Bulletin No. 25 of the United States Bureau of Mines, Washington. A similar series of tests, more extensive and more elaborately-planned, were subsequently made for the Pennsylvania Mine Cave Commission at the U. S. Government Testing Laboratory at Pittsburgh, Pa. The report of this Commission was made to the Governor, but has not yet been published.

Jan 10, 1917

By R. D. Nelson, S. D. Dahlgren

The conditions of temperature, strain rate, and total strain favoring deformation by grain boundary sliding, slip, or deformation with concurrent recrystallization were evaluated for alpha plutonium. Grain boundary sliding and slip were studied by examining structures formed on polished surfaces with 4.5 pct compressive deformation. The conditions required for recrystallization were determined from compressive deformation us time curves. At 110" C and at a strain rate of 10&apos;per min, deformation was almost exclusively by grain boundary sliding whereas slip was the predominant deformation mode at -10°C and lo-&apos; per min. Defarmation at intermediate tenzperatures and strain rates produced structures showing mixtures of grain boundary sliding and slip. Recrystallization occurred concurrently with deformation only after a critical strain was reached. About 14, 6, and 3 pct strain was required at 105", llO°, and lZO°C, respectively, before recrystallization started, irrespective of the strain rate in the range of lo-&apos;1 to 10&apos;4 per nzin. L HE temperature and strain-rate dependency of the modes of plastic deformation were evaluated for high-purity as-cast alpha plutonium. The techniques used to study slip and grain boundary sliding were similar to those employed previously for alpha plutonium by Bronisz and Gorum,&apos; and spriet.&apos; Recrystallization was investigated using the methods reported by Nelson.3 Bronisz and Gorum&apos; found that slip occurred on more than one slip system at room temperature, and suggested that grain boundary sliding also contributed to the deformation. spriet2 found that deformation was predominantly by slip at room temperature, and observed one to three orientations of slip traces in individual grains. In addition, he deformed polished samples at 10O° C, but concluded that the deformation character of alpha plutonium at 100° C and at room temperature were not essentially different. Several investigators reported that twinning was only occasionally observed.1&apos;2&apos;4 Nelson3 recently found in creep tests that high-purity alpha plutonium would recrystallize concurrently with compressive deformation at temperatures between 25" and 115°C. EXPERIMENTAL PROCEDURE Electrorefined plutonium having less than 300 ppm total impurities was received from Los Alamos Scientific Laboratory in the form of +-in. diarn cast rods. Major impurities were americium, <I00 ppm, and tungsten, (60 ppm. Less than 25 ppm each of other impurities were present. The rods were cut into right half-cylinders 0.35 in. long and 0.25 in. in diam, and the flat faces along the cylinder axes were metal-lographically polished. To avoid loss of the metallo-graphic polish by oxidation, the polished samples were deformed in a silicone fluid heat treating medium contained in a chamber evacuated to a pressure of lo-&apos; torr. Deadweight loading was used to compress the samples between 4.5 and 20 pct at strain rates between 10"4 and lo- &apos; min-&apos;. Strain rates were determined by dividing the total deformation by the elapsed time of the test, even though the strain rate was not constant during deformation. Curves of strain vs time for samples deformed with a constant compressive stress3 show that the strain rate changes by less than a factor of four during the testing of a given sample, which is small compared to the three orders of magnitude change in strain rate investigated. Two samples were loaded into an ordinary metallographic mounting mold and impacted by striking the mold piston with one blow of a 2-lb hammer. Deformation temperatures for the two impact samples were 25" and 90°C. The samples, following deformation, were washed in carbon tetrachloride and their polished and deformed surfaces were immediately inspected metallographi-cally. Subsequently, the deformation structures were replicated with acetate replicating tape for later electron microscope examination, and the samples were then repolished and etched to reveal the microstruc-tures of the deformed metal. Second-stage carbon replicas were prepared from decontaminated acetate replicas using the procedure developed by Miller, Bierlein, and astel.&apos; Additional samples, which were 0.35 in. long by 0.25 in. in diam, were used to obtain constant load deformation vs time curves. These samples were deformed 10 to 20 pct with loads of 15 and 20,000 psi at 120°C; 30, 45, and 55,000 psi at 110°C; and 20 and 30,000 psi at 105°C. Samples were polished and etched to determine whether or not recrystallization or twinning had occurred during deformation. RESULTS AND DISCUSSION The experiments showed that alpha plutonium deforms by grain boundary sliding, slip, and deformation with concurrent recrystallization. Deformation by twinning was insignificant. Metallographic examination of polished and deformed surfaces revealed grain boundary sliding and slip. The start of recrystallization was ascertained from constant load deformation vs time curves. Deformed surface structures of samples compressed 4.5 pct under four different conditions of temperature and strain rate, Fig. 1, show how the deformation mode changes from predominantly grain boundary sliding to predominantly slip with increasing strain rate and decreasing temperature. Deformation at 110°C and 10" 4 min-&apos;, Fig. l(a), was predominantly by grain boundary sliding. Only a few slip traces can be seen in Fig. l(a).

Jan 1, 1969

By Donald W. Barnett

U.S. environmentalists have tended to oppose all new energy developments. Their efforts may be counterproductive because opposition to, say, offshore oil directly leads to the continued use of other energy sources that may have a higher social cost. Rather than attempting to eliminate all pollution from energy production, which would be prohibitively expensive, one should minimize the social cost of energy production for the given demand. Linear programming is used to rank various oils (California State and O.C.S., Gulf of Alaska, Prudhoe Bay, Athabasca tar sands, oil shale and certain foreign crudes) in terms of their social desirability. The objective is to minimize the cost of supplying the California market, subject to resource, sulphur and oil spill constraints. Social desirability is indicated by the inclusion of the oil in the optimal solution and the size of the associated shadow price. the larger the shadow price, the greater the benefits of increased production. The more negative, the greater the cost associated with forcing consumption of that fuel. The environmental shadow prices indicate the size of the trade-off between a particular environmental standard and minimum cost. The trade-offs can be surprisingly large. any reasonable spill standard can be achieved by changing the development pattern. Generally, the further offshore, the smaller is the environmental degradation, but the more expensive is the oil. Foreign oils can be economically and environmentally inferior to domestic oils. Crude from the California O.C.S., San Joaquin Valley end Prudhoe Bay appears a valuable resource, while the Gulf of Alaska, synthetic and foreign crudes appear marginal to submarginal.

Jan 1, 1977

By R. W. Raymond

THE death of Privy Councilor Bruno Kerl, on March 25, 1905, terminated a distinguished and useful career. Bruno Kerl was born March 24, 1824, at St. Andreasberg in the Harz, and entered in 1840 the mining school of Clausthal, where he studied for three years, working at the same time in the mines and stamp-mills. After an additional year of practice in the silver-reduction and iron-works of the Upper Harz, he passed his examination as a metallurgical graduate, and studied for a year at Göttingen under WV filer in chemistry, Hausmann in mineralogy, and eminent teachers in other branches. In 1846 he was employed at the Oker works, but very soon left this post, to become a tutor in chemistry, metallurgy, etc., at Clausthal, where he continued to labor until 1867. During this period the Clausthal school became a completely equipped Mining Academy, and Kerl was made in 1862 a full professor. Meanwhile, in addition to the work of instruction, he discharged, simultaneously or successively, the duties of many responsible official positions in the Royal Hanoverian administration of mines and smelting-works, and also published many valuable books and treatises. Among these were professional guide-books to the Upper and Lower Harz, and their characteristic metallurgical processes; a manual of qualitative and quantitative blow-pipe analysis; another of metallurgical assaying ; and, most important of all, a Handbook of Metallurgy in four volumes, the second edition of which was issued in Leipzig, 1861-1865. This book was speedily recognized as the leading authority in its field. In this country, the English translation and revision, by Crookes and Röhrig, published about 1869, had a large circulation. In addition to these literary labors, Prof. Kerl became in

Jul 1, 1905

By R. DiBella, H. Biloni, G. F. Bolling

A study of the detailed relationship between solidification substructure and microsegregation in dilute tin alloys has been continued. New observations reveal that depressions form at the solid-liquid interface not only as an initial form of segregation but throughout the range of increasing constitutional supercooling. In order to show the importance of this node formation it proves convenient to make two simplifications. Although substructure changes continuously as constitutional- supercooling increases,&apos; the following discrete stages may be used for discussion: 1) the planar solid-liquid interface; 2) ordered nodes, or depressions at the interface;&apos; 3) two-dimensional or elongated cells;3 4) regular or hexagonal cells;4 5) distorted cells, or hexagonal cells with branches;4 6) dendrites. It is also convenient to ignore observations made near grain boundaries which interact with the cellular substructure.2-4 And, it should be clearly pointed out that all singular depressions at the solid-liquid interface will be called nodes. Heretofore, the term "node" has been used without clear justification to describe both the truly isolated depression and the junction of cell walls appearing in a later stage of segregation. This usage is continued because it seems proved by the observations. Standard systematic growth of tin crystals was undertaken over a broad range of constitutional supercooling using various added solutes. Except for one or two chance observations, this research failed to reveal any appreciable range of growth conditions over which a disordered array of isolated nodes exists. Even though &apos;some finite range of random instability must exist, it is now concluded that stage one passes very rapidly to stage two. Next, after confirming that stage two passes to stage three by the elongation of isolated nodes: a reexamina-tion of stages three, four, and five followed. Standard metallography showed that pockets of higher solute concentration (for ko < 1) became more numerous in cell walls the more severe the growth conditions. These high-concentration regions must arise from depressions; however, in stage three their segregation is not distinguishable from the segregation of the nodes which join cell walls together. It seems, therefore, that the presence of nodes is causal in the formation of new cell walls, and that the mechanism by which stage three passes to stage four is initiated by nodes. If a similar reasoning is followed, the separation of stage four from stage five appears to be just a convenience that has arisen from the decanted interface observations made in the past. The present observations again show that more severe growth conditions relate directly to an increase in the number of nodes in the hexagonal cell walls. These nodes apparently serve as the origin for lines of segregation extending within the body of a cell, and can thus be assumed to represent the earliest form of branching,* as shown here in Fig. 1. The examination of stage six involved decanted-interface structures as in Fig. 2, which are similar to those considered by Rutter and Chalmers,5 Plaskett and winegard,6 and Hellawell and Herbert,7 and where distinct protrusions are each surrounded by a depressed boundary. The corresponding microsegregation behind the interface, but not far enough behind to allow a smearing of the segregation because of diffusion,4 is shown in Fig. 3. Both the shape of the decanted interface and the segregation pattern behind it

Jan 1, 1968

By Marius R. Campbell

Does mine-sampling show the commercial value of a coal, and if so, how should it be done ? This question is often asked, but seldom answered. During the past summer, while engaged in securing coal for the Government coal-testing plant at St. Louis, I had an excellent opportunity to obtain information on t,his subject, and the results seem to furniih an answer to the question propounded above. Sampling for the U. 8. Geological Survey Coal- Testing Plant. In organizing the work of the testing-plant, it was decided that coal, in car-load lots only, would be accepted for testing; also that this coal should be loaded under the immediate supervision of a representative of the plant, so as to be certain that the car-load sample would be representative. As an additional check on the work, two mine-samples were to be collected from each mine visited, and these samples, as well as the sample from the car when it was received at the testing-plant, were to be carefully analyzed at the chemical laboratory established in connection with the plant and operated under the direction of Prof. N W. Lord of the Ohio State University, Columbus, Ohio. Mine-Samp1ing.—Mine-samples were collected with great care by me and my assistants, Messrs. J. Shober Burrows, John W. Groves and Frank W. De Wolf. The dominant idea in the regulations adopted for mine-sampling mas, that it should be done in such a manner that the sample would have the same composition as the commercial output of the mine.

Jan 1, 1906

By John Henderson

Densities of melts 0f the lime-iron oxide-silica system in contact with solid iron have been measured by the maximum bubble pressure method in the temperature range 1250° to 1440°C and the composition range 0 to 40 mol pct lime, 15 to 100 mol pct iron oxide, and 0 to 55 mol pct silica. Densities range from 4.65 g cm 3 for wustite at 1440°C to 2.75 g cm-&apos; at 1350°C for a melt containing 30 mol pct lime, 20 mol pct iron oxide, and 50 mol pct silica. The results are interpreted in terms of a postulate that the melts can be regarded as a random array of oxygen ions in which regions of local order exist to satisfy the coordination requirements 0.f the cations. An understanding of the nature of metallurgical slags is basic to the development of a sound theoretical description of heavy metallurgical extractive and refining processes. Because these liquids are complex, direct measurements of their properties has not thrown much light on their structure. This has led to the approach of measuring the properties of simpler liquids, and building up their complexity until slag compositions are reached. In this way the density of liquid iron silicates was measured in a previous study1 and the present work represents a further stage in this synthesis. EXPERIMENTAL The technique used in the measurement of density was the maximum bubble pressure method. Details of the apparatus and procedure were similar to those previously reported,&apos; with the exception that a constant voltage transformer was used to supply the power input to the furnace and six silicon carbide resistance elements were used in place of the molybdenum winding. With these modifications melt temperature could be maintained within 1 centigrade degree during the course of a run. The silica used to prepare the melts was washed natural quartz ignited at 1000°C; wustite was prepared by air-melting A.R. grade ferric oxide in an iron crucible and lime was prepared by air ignition, at 1000°C, of weighed quantities of A.R. grade calcium carbonate, previously air-dried at 110°C. The finely ground constituents were intimately mixed in a glass ball mill prior to melting. Temperatures quoted are accurate to * 5°C and the standard deviation of the density values, calculated by the method of least squares, ranged from 0.5 to 1.8 pet. However, replicate determinations of density on different melts of the same nominal composition at the same nominal temperature did not vary by more than 1 pct, Table I, and this figure has been taken as an estimate of the accuracy of the density results. The density of carbon tetra-chloride was also measured as a check on the absolute performance of the experimental method. At 20°C a value of 1.593 * 0.002 g cm"3 was obtained; this compares with the literature value2 of 1.595 g cm"3. Results of experiments designed to measure the dependence of the density of lime-iron oxide-silica melts, in contact with solid iron, on composition and temperature are shown in Table I. Because iron sometimes precipitated in the sample during quenching, the Fe203 chemical analyses were only poorly reproducible and should be taken as a guide rather than as absolute values. Fig. 1 shows the data from various sources for the density of liquid iron silicates and Fig. 2 shows isodensity contours at 1410°C for lime-iron oxide-silica melts, calculated by graphical interpolation of smoothed curves drawn through the experimental results, together with the 1400°C results of Adachi and ogino3 and Pope1 and Esin.4 Fig. 3 shows the isothermal variation with composition of the volume of melt per gram ion of oxygen at 1410°C and Fig. 4 shows regions in which the temperature coefficient of this volume is negative, positive, or negligible (<0.005 cm3 deg-I). DISCUSSION a) Disparity Between Reported Density Results. Consider the system iron oxide-silica, the results for which are summarized in Fig. 1. Although there is some difference in the temperatures at which the various densities apply, this difference is not sufficiently large to account for the observed discrepancies. The reliability of the present results for the low-silica region has been confirmed by measurement of the density of liquid wustite by three different techniques. At 1410°C the density measured by a balanced-column method was 4.55 g cm"3, by a combination balanced-column and gas-densitometer method 4.59 g emd3, and by a pycnometer method 4.53 g cm"3. Schenck, Frohberg, and Hoffermann&apos; have also reported a value of 4.55 g cm"3 for the density of liquid wustite at 1400°C. It must be concluded, therefore, that neither Pope1

Jan 1, 1964

By W. F. Wheeler

In the study of the coals of Illinois now being carried on by the State Geological Survey, an attempt is being made to determine the most satisfactory basis of comparison between different coals. The following discussion is based upon work done for the Survey in the laboratories of the State University and under the general direction of Prof. S. W. Parr. "Pure coal" has been defined by Mr. A. Bementl as ash- and moisture-free coal, and the use of this pure coal" as a basis for comparing different bituminous coals has lately been much discussed among engineers in the middle West. By some the B.t.u. of the pure coal is being used to check calorimetric results, and to calculate the calorific value of different coal-samples from the same seam, for which purposes it is necessary to assume—first, that the composition and calorific value of pure coal from different parts of the same coal-seam are uniform, and, second, that these values remain constant after the coal is mined, both of which assumptions there are reasons to believe are inconsistent with the facts. Certain variables are included in pure coal, as ordinarily defined, and disregard of them may lead to serious error. In any event, where delicate shades of difference are involved, no sure interpretation of results car] be made, unless these variables be eliminated. As a basis of comparison between coals, ash- and moisture-free coal is much to be preferred to " dry coal," and still more is it to be preferred to moist coal," as ordinarily reported in analyses. There are, however, two constituents other than ash

Jan 1, 1908

By D. A. Elgillani, M. C. Fuerstenau

In this paper, oxidation potentials measured in the presence of various concentrations of cyanide, ferro-cyanide, and ferricyanide and ethyl xanthate at various values of pH are related to flotation response. Eh-pH diagrams are presented to show that the formation of surface ferric ferrocyanide is probably responsible for depression when cyanide is added. The influence of cyanide on the depression of pyrite with xanthates as collector has been the subject of a number of investigations,&apos;-6 and several theories on the mechanism of depression have evolved from these studies. Wark and Cox7 and Gaudin8 have suggested that the depressing effect is due to a competition of cyanide ion with xanthate ion for the surface. Cook and his colleagues9-11 have explained this phenomenon in terms of competition between hydrocyanic acid and xanthic acid. Sutherland 12 has shown that although both of these theories accurately describe the relation between pH value and cyanide addition at constant collector addition, they fail to describe the relation between pH value and the amount of collector required to cause flotation. Taggart 13 suggested that depression in these systems is due to the formation of a reaction product between ferric ion at the pyrite surface and ferrocyanide ion derived from solution. Majumdar4,6 has attempted to prove this hypothesis by measuring the contact angles of pyrite in the presence of 25 mg per liter ethyl xanthate and different concentrations of potassium ferrocyanide and ferricyanide. In all cases the contact angles were quite high up to pH 10. These results indicate that pyrite should not be depressed by either potassium ferrocyanide or ferricyanide. In view of these facts, Majumdar has assumed that the compound Fe(CN)2 forms at the surface. Gründer and Bornl4 have stated that depression may be due to the formation of the compound K2Fe(II)Fe(CN)6 at the pyrite-solution interface. This compound is thought to be an interaction product between the K2Fe(CN)6-2 ion from solution and the Fe++ ion at the pyrite surface and, accordingly, K4Fe(CN)6 should depress pyrite at least as effectively as KCN. This was proven experimentally, but there was no simple relation between the depression of pyrite and the concentration of either KCN or K4Fe(CN)6 in solution. In view of the many mechanisms that have been proposed for pyrite depression by cyanide, it is apparent that a clear understanding of the phenomena occurring in these systems is lacking. One reason for this may be the fact that the species responsible for pyrite flotation in the presence of xanthate is not the xan-thate ion but rather dixanthogen.15 Since the oxidation of xanthate to dixanthogen is dependent on the oxidation potential of the solution, it would seem that knowledge of these potentials would be a requisite to understanding the pyrite-xanthate-cyanide system. It is the object of this paper to measure both the oxidation potential and pH of the pyrite systems in the presence of various concentrations of cyanide, ferrocyanide, and ferricyanide and xanthate and to relate these values to flotation response. EXPERIMENTAL MATERIALS AND &apos;TECHNIQUES In the experiments discussed here, pure potassium ethyl xanthate was used as collector, and reagent grade potassium cyanide, potassium ferrocyanide, and potassium ferricyanide were used as depressants. Reagent grade HC1 and KOH were added for pH adjustment. Conductivity water, made by passing distilled water through an ion exchange column, was used in all experimental work. Two natural samples of pyrite were used in the investigation. Sample preparation for flotation included dry grinding with a mortar and pestle and sizing the product to 100 x 200 mesh. Prior to flotation, a 0.75-gm sample of pyrite was added to a solution containing a known amount of depressant at the desired pH value, and the system was conditioned for 4 min. Following this, a known amount of collector was added and the system was conditioned for another 4 min. The pH — termed flotation pH - was measured; the pulp was transferred to a Hallimond cell, and flo-

Jan 1, 1969

By CHARLES SIMENSTAD

COAL preparation, or coal washing, is not a new subject to the Pacific Northwest. Most of the coals mined in this state smaller than lump, and nearly all such sizes mined on the Pacific slope of the Cascade mountains, require washing before marketing. A large proportion is being put through some washing process, but coal washing in this state, has not reached the efficiency it is practicable to obtain. In fields where the coal, as mined, contains less impurities, where working conditions make it practicable to eliminate some of these impurities under- ground, or where a large proportion of the run-of-mine coal is lump, coal preparation does not present the problem it does in our local field. Here the coal is associated with considerable impurities and the slack, or steam sizes, aggregate about 80 per cent. of the output. Therefore, approximately 80 per cent. of the coal mined must be washed to become a valuable fuel. Washing then becomes a major operation, as hand picking of the 20 per cent. of lump is a standard and comparatively simple operation. Some coal beds here are so interstratified with bone, of a more or less massive nature, that hand picking of lump is not economically efficient. In such cases the coal must be crushed fine enough for it to be freed from the bone, so that the two may be separated. Coal cleaning in this field, therefore, must receive skilled attention to purify this fuel and raise its stand- ard. Without greater efficiency in cleaning, the importation of coal from outside the state will be even greater than in the past.

Jan 1, 1926

By S. G. Lasky

W E seem to have assumed the careless habit in recent years of treating mining geology as synonymous with exploration geology, and exploration synonymous with exploration for new deposits-to be forgetting that mining geology includes also the geologic control or guidance of day-by-day mining operation. In the publicized romantic spotlight of the search for new deposits, we forget the man with the dirty over-alls, grubbing away at the daily tasks of finding new shoots and of helping to keep production up and cost down. During 1949, as in previous years, the resident geologist continued his quiet efficient functioning while the exploration geologist continued to stay in the spotlight-although this time he shared it with what may be called the resource-appraisal geologist. Many broad problems of national import such as tax modification, the operations of the Economic Cooperation Administration, and certain international relations have come up against an unexpected factor lurking in the background, namely, appraisal of world and domestic reserves and latent resources. T. M. Broderick opened the year with his address as retiring president of the Society of Economic Geologists, wherein he analyzed the problems of exploration geology listing among them "the shortcomings of the geologists themselves, of the educators, the mining companies, our Published by permission of the Director, U. S. Geological Survey. technical publications, the Federal Survey and Bureau of Mines, and the property owners."

Jan 1, 1950

By C. A. Hartnagel

The production of petroleum in New York state in 1942 amounted to 5,410,000 bbl. This represents an increase over each of the four preceding years, and, with the exception of 1937, is the largest production since the peak of over six million barrels in 1882, shortly after the discovery of oil in Allegany County. The oil industry in New York is virtually stabilized and there has been little or no exploration for new sources of supply in recent years. The boundaries of the present fields were established more than 30 years ago and since then no additional reserves have been found. Deep drilling for natural gas during the past 10 years both within and without the oil fields has failed to find oil in quantity below the present producing sands of Devonian age. Oil Since 1882, the New York fields have produced approximately 140 million barrels of oil. Of this amount, 65 million was produced up to the year 1919 by ordinary pumping methods; that is, without flooding by water or the use of other secondary-recovery methods. In the year 1919, when a law was passed making the use of water-flooding methods legal, the oil production, of the state amounted to only 851,000 bbl. In the 23 years since 1919, there have been produced in the state 75 million barrels, or 10 million more than in the previous 37 years, which included the period of flush production. Price.—On March 26, the price of crude oil was raised from $2.75 to $3.00 per barrel, hut this increase had little or no effect on the number of wells drilled. In the Allegany field, which accounts for three fourths of the state&apos;s oil production, 1259 wells were completed in 1942, 7 less than in 1941. The smaller number of wells drilled was not only due to the shortage of labor but also was caused by the fact that in water-flooding territory a definite program for drilling wells is followed, and the flush period of an oil well is not usually reached in time to profit by any given price increase. Daily Production.—All of the oil wells in New York state, some 21,000 in number, are small producers. The average daily oil production is 7/10 bbl. per well. Under good flooding conditions, a maximum production of 5 to 8 bbl, a day is reached about one year after the flood begins to act on the well. In 5 years the daily production usually is less than one barrel. Although most of the oil in New York is produced by flooding, an estimated 2500 old wells produce without flooding. Some of these produce as little as 1/20 bbl. a day and are pumped only at intervals. The small producing Wells are mostly on lands leased to the larger oil companies and later will be included in a flooding program. At present, they are pumped only because the owners of the land insist on the royalty. Government Aid Needed.—Because of its good lubricating qualities, New York oil is one of those for which there is an insistent and growing demand, but even at its present price of $3.00 per barrel, many of the operators are producing at a loss.

Jan 1, 1943

By C. A. Hartnagel

The production of petroleum in New York state in 1942 amounted to 5,410,000 bbl. This represents an increase over each of the four preceding years, and, with the exception of 1937, is the largest production since the peak of over six million barrels in 1882, shortly after the discovery of oil in Allegany County. The oil industry in New York is virtually stabilized and there has been little or no exploration for new sources of supply in recent years. The boundaries of the present fields were established more than 30 years ago and since then no additional reserves have been found. Deep drilling for natural gas during the past 10 years both within and without the oil fields has failed to find oil in quantity below the present producing sands of Devonian age. Oil Since 1882, the New York fields have produced approximately 140 million barrels of oil. Of this amount, 65 million was produced up to the year 1919 by ordinary pumping methods; that is, without flooding by water or the use of other secondary-recovery methods. In the year 1919, when a law was passed making the use of water-flooding methods legal, the oil production, of the state amounted to only 851,000 bbl. In the 23 years since 1919, there have been produced in the state 75 million barrels, or 10 million more than in the previous 37 years, which included the period of flush production. Price.—On March 26, the price of crude oil was raised from $2.75 to $3.00 per barrel, hut this increase had little or no effect on the number of wells drilled. In the Allegany field, which accounts for three fourths of the state&apos;s oil production, 1259 wells were completed in 1942, 7 less than in 1941. The smaller number of wells drilled was not only due to the shortage of labor but also was caused by the fact that in water-flooding territory a definite program for drilling wells is followed, and the flush period of an oil well is not usually reached in time to profit by any given price increase. Daily Production.—All of the oil wells in New York state, some 21,000 in number, are small producers. The average daily oil production is 7/10 bbl. per well. Under good flooding conditions, a maximum production of 5 to 8 bbl, a day is reached about one year after the flood begins to act on the well. In 5 years the daily production usually is less than one barrel. Although most of the oil in New York is produced by flooding, an estimated 2500 old wells produce without flooding. Some of these produce as little as 1/20 bbl. a day and are pumped only at intervals. The small producing Wells are mostly on lands leased to the larger oil companies and later will be included in a flooding program. At present, they are pumped only because the owners of the land insist on the royalty. Government Aid Needed.—Because of its good lubricating qualities, New York oil is one of those for which there is an insistent and growing demand, but even at its present price of $3.00 per barrel, many of the operators are producing at a loss.

Jan 1, 1943

By AIME AIME

THE Committee on Elimination of Waste in industry came into existence from a speech in Washington by Mr. ,Hoover, in November, in which, he said: It is primary to mention the three-phase waste in production: first, from intermittent employment; second, from unemployment that arises in shifting of industrial currents; and third; from strikes and lockouts. Beyond this elimination of waste there is another field of progress in the adoption of measures for positive improvement in production.

Jan 1, 1921

By R. D. Carnahan, J. E. White

A study of dispersion strengthening in TD-Nickel (nickel plus 2 vol pct Tho2) was conducted employing microstrain techniques at ambient room temperature. It was found that optimum strength was due primarily to the incorporation of stored energy developed by a variety of thermal-mechanical treatments. The relatively low strength of the recrys-tallized condition implies that the dispersed particles themselves offer only token resistance to deformation. The development of resistance to large-scale recovery or recrystallization at temperatures near the melting point requires a more extensive sequence of strain-anneal cycles than does the development of optimum strength. A micro-Bauschinger effect was observed which appears to be related to the lattice resistance to the movement of free dislocations. The effect was nearly identical to that in pure nickel indicating that the presence of the dispersed phase and considerably increased dislocation density (stored energy) only alters the number or effectiveness of barriers. THE early stages of deformation of engineering materials can be conveniently studied by utilizing strain-gage techniques which permit resolution of strains less than 5 X 10-7 in. per in. for testing in four-point bending (Carnahan and white1). The present investigation, part of a continuing study on the very early stages of deformation, was designed to reveal the true role of a dispersed phase in promoting high strength in a commercially available dispersion-strengthened alloy. Although this technique has been used for some time to study microdeformation in pure metals and alloys, it has just recently received attention as a means of investigating dispersion strengthening. Studying the very early stages of deformation in alloys which depend upon a finely dispersed inert phase for strength may prove to be a very important method for a better understanding of these materials. It is essential to obtain considerable clarification of actual dislocation movement and the kinds of deformation barriers which exist before optimum properties can be designed into this type of material with any degree of confidence. Considerable research on a variety of dispersion-strengthened materials has resulted in two different schools of thought regarding the strengthening mechanism. One faction2-4 favors the idea that the particles themselves resist the motion of dislocations. The criterion for yielding is the fracture of the dispersed second-phase particles due to an array of piled-up dislocations. Other invesfigators5-a have shown that particles are effective primarily by allowing a greater buildup of stored energy or dislocation density through thermal-mechanical treatments in the composite than the pure matrix material. The particles themselves, then, are not exclusive obstacles, but the complex network of particles, dislocation tangles, subboundaries, and grain boundaries are strength determining. The development of such a complex dislocation network in SAP has been studied recently in some detail by Goodrich and Ansell. The ability of dispersion-strengthened alloys to resist softening or recrystallization is also of considerable importance; however, the criteria for maximum stability may not necessarily be those for maximum strength. In this study, in addition to the evaluation of the microstrain properties of TD-Nickel, it is felt that considerable clarification of the true dependence of strength and stability on the dispersed phase is shown. I) MATERIAL AND PROCEDURE TD-Nickel is a dispersion-strengthened alloy developed by the E. I. DuPont de Nemours Co., which contains 2 vol pct thoria (Tho2) in a pure-nickel matrix. The average ThO2 particle size is approximately 0.1 p and the interparticle spacing is less than 1 u. The material was supplied by DuPont in two conditions: hot-extruded bar stock, and stress-relieved cold-rolled sheet 0.025 in. in thickness. The bar was extruded at 2200°F from a cold-pressed and sintered billet. The sheet stock was prepared from the extruded material by a process involving ten or more 50-pct cold reductions by rolling with intermediate anneals at 1800° to 2000°F. Test specimens used in this study were prepared in the form of rectangular parallelepipeds measuring 0.375 by 1.375 in. in thicknesses ranging from 0.025 to 0.040 in. Samples prepared from sheet and extruded stock were mechanically polished before heat treatment and were handled with extreme

Jan 1, 1964