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By Charles Macdonald

WROUGHT-IRON eye-bars for bridges and roofs, designed upon what is known as the pin connection system, have been successfully manufactured in this country for some years. The most approved methods employed have been the hydraulic upsetting process, and by die-forging under a hammer. In upset eyes the fibre of the iron is necessarily much distorted ; and in bars of considerable size, this disturbance seriously impairs the strength of the connection. Mr. Collingwood, in discussing my paper on "Proportions of the Heads of Eye-bars," read before the American Society of Civil Engineers, Jan. 21st, 1874, submitted sketches of certain bars intended for the anchorage of the East River bridge, which had been exposed to the action of sulphuric acid a sufficient length of time to thoroughly cleanse the surfaces, and expose the condition of the fibre. These sketches are here reproduced for the purpose of illustrating the effect of this methpd of manufacture. In Figs. 1, 2, and 3, it will be observed that the fibres at A, and E, have been folded back upon themselves and otherwise twisted and disturbed, in a manner not calculated to inspire confidence in the integrity of the connection. To compensate for this defect, a large excess of metal is thrown into the eye; but a method of manufacture which involves such a necessity, even although it be the one giving the best results thus far, all things being considered, is far from being perfect.

Jan 1, 1879

Manganese deposits discovered in Maine may solve one of the problems facing the steel industry today. Diamond drilling is scheduled to start in Aroostook County to determine whether the ore is of acceptable grade. The Bureau of Mines estimates the deposit contains several hundred million tons. If true, it means about a 30-year supply. The steel industry presently imports about 90 pct of its needs. Noranda Mines, Ltd., is planning a sulphur-iron plent for Ontario's Niagara Peninsula. Although contracts have not been signed, a substantial agreement has been reached with American Cyanamid, Ltd., whereby the Noranda plant would be constructed adjacent to Cyanamid's chemical plant at an estimated cost of million. The unit would treat approximately 100,000 tons of pyrite concentrate annually. San Manuel Copper Corp., wholly-owned subsidiary of Magma Copper Co., is asking the RFC for a $111.28 million loan for development of a copper orebody in Pinal County, Ariz. The property s said to be capable of producing 10 million tons of ore annually. San Manuel plans to construct facilities for processing 30,000 tons of ore and for smelting 800 tons of concentrate daily. An Aeromagnetic map covering 120 sq miles of the Wichita Mountain area in southwestern Oklahoma indicates a possibility of iron production from titaniferous magnetite deposits of the Raggedy Mountains, northwest of Lawton. The map shows an area in the north central part of the region which may prove favorable to further development.

Jan 1, 1952

By S. F. Kelly, Theodor Zuschlag, Bela Low

Gold has been mined in the state of Georgia for over 100 years, and although the total production is nearly $18,000,000, the output has declined to an insignificant figure in recent times. The increase in price of gold has brought about a revival of interest in this district, with the result that an electrical survey was undertaken in the McDuffie County gold belt to see whether new quartz veins could be discovered. The problem of locating quartz veins electrically has only rarely been attempted by geophysicists, because of technical difficulties. New improvements in apparatus and field procedures, the most recent of which is the designing of the Ground Comparator, now make possible the differentiation of quartz veins and enclosing rock. This instrument is designed to eliminate the effect of ground contact resistances, and measures the ratio of potential drops between successive stations. These are transformed into resistivity ratios, the highly resistant quartz veins manifesting themselves by sharp breaks in the resistivity-ratio curves. Surface variations of resistance are eliminated by a special technique. Electrical surveys were made on two properties about 40 miles west of Augusta, Georgia. A reconnaissance of the Woodall and detail work on the Hamilton required about. 13,000 ft. of electrical profile. Typical profiles from each are given, with the results of trenching certain of the electrical indications. Comparisons are made between the reactions due to veins several feet wide and those from small quartz stringers. Instances are cited where the electrical profiles were used to trace extensions of known veins, or to establish their nonextension. The discovery of several veins is described, most of which were barren, but of which at least two showed gold in encouraging amounts. The field of application of the Comparator to the prospecting for metallic and nonmetallic minerals, and to the study of various geological problems, is discussed at the close of the paper.

Jan 1, 1934

By A. K. Sinha

The annual production and productivity of underground coal mines in recent years declined from 334 Mt (368 million st) and 14.5 t (16 st) per man per shift in 1969 to approximately 254 Mt (280 million st) and less than 8 t (9 st) per man per shift in 1977. Productivity is still hovering at about 7.25 t (8 st) per man per shift. According to US Bureau of Mines, the estimated US coal reserve is about 396 Gt (437 billion st), 68.65% of which is obtainable by underground mining methods. Approximately 153 Gt (169 billion st), or about 85.2% of the high Btu premium coking coal of the eastern US, would need to be extracted by underground mining methods. It is thus apparent that under- ground mining will continue to play a major role in total US coal production, which is expected to rapidly increase to about 1.1 Gt (1.2 billion st) by 1985, with about 606 Mt (668 million st) being contributed by underground mines. Production Potential of Continuous Mining The production potential of a continuous mining section depends primarily on the producing ability of the miner, transporting ability of the face haulage, and the matching of the two systems. The producing ability of the continuous miner depends on its actual cutting ability and the time available for cutting coal. The performance of 10 continuous miners operating in coal seams of various thicknesses were monitored in Pennsylvania and West Virginia, using continuous electrical power analyzers and time studies. The recordings on current and power strip charts yielded an accurate analysis of the cutting, trimming, and idle times of the machines on a full shift basis. Continuous miners of various models and sizes from 112-298 kW (150-400 hp) were monitored. Based on actual cutting time, the average cutting ability of the machines, as shown in [Fig. 1], ranged from

Jan 1, 1983

By Valentin R. Garfias

The world's petroleum production in 1929 is estimated at 1,479,335,-000 bbl., which represents an increase of about 157,000,000 over 1928, as compared with an increase of 61,000,000 bbl. in the previous year. During the present year a more definite policy of conservation has been seriously considered by the foremost executives of the companies controlling the bulk of domestic and foreign production, and the United States Government has taken an active interest in the development of this program. Definite steps have already been taken and the industry is gradually establishing a foundation for closer and more intelligent cooperation. The entire program, however, is still in a formative or experimental stage. Among other salient constructive steps may be mentioned the establishing of tentative agreements of unification in the price of oil products exported from the United States, the putting into effect of a gas conservation law in California, and the marked tendency towards consolidatlions of the various branches of the industry into larger units. The publication of the draft of the proposed petroleum law in Colombia and of the Mexican Labor Law, on the other hand, has created papre-hension and uncertainty. It is confidently expected, however, that these perliminary drafts will be materially modified before the laws arc promulgated, or otherwise they may destroy the interest they are intended to protect. United States Production in the United States, which remained stationary during 1927 and 1928, increased about 105,000,000 bbl., or 11.6 per cent. This increase is due primarily to deeper drilling in the California fields and to the discovery of new pools in Texas and Oklahoma. The progress of the conservation program was marked by the action of the Government in stopping further permits to drill on Government lands; by putting into effect early in September the California Gas Conservation Law, and by

Jan 1, 1930

By W. C. Weslow

AN extended program devoted to the development of a matrix for holding diamonds of a size and kind not heretofore generally used is being carried on by the Carboloy Company, and this paper describes the part of the development that affects mining and its allied industries. Laboratory and field work so far has indicated the following: 1. Tungsten carbide and cobalt form the most desirable known matrix material for the holding of diamonds for drilling work. 2. Industrial bort diamonds in sizes and of a class not generally heretofore acceptable and therefore less expensive can be successfully held in this cemented carbide matrix. 3. In exploratory drilling, the combination of bort diamonds, impregnated throughout a matrix of tungsten carbide and cobalt, when fabricated onto drilling crowns, is an indicated economic substitute for drilling crowns in which the diamonds are set by hand, mechanically or by casting. 4. This impregnated type of drilling crown or bit has definite possibilites of revolutionizing the drilling of blast holes, particularly in the harder formations. This will be brought about by the development of high-speed light-weight rotary equipment using an impregnated diamond bit to replace the percussion drill now in general use. (The development of this rotary equipment is well past the laboratory stage at this time.) 5. That the use of a rotary bit is a preventive measure in the fight against silicosis. The development of this product was started by G. F. Taylor at the Research Laboratories of the General Electric Co. It was early recognized that it had possibilities in the drilling field and the present product is the result of considerable experimental work with other powdered metals as well as with tungsten carbide and cobalt. In the study of the potential application to the mining field, it was learned that carbon diamonds originally were given a high rating of performance but that the trend had been toward borts in selected sizes

Jan 1, 1940

By Frederic Benard

THIS paper constitutes a preliminary report on experimental work done to date on the anode-furnace treatment of blister copper containing relatively high percentages of nickel. The investigation has not been completed but results obtained to date are considered of sufficient interest to warrant publication. Blister copper treated by the Ontario Refining Co. originates from the Copper Cliff smelter of The International Nickel Company of Canada, of which the former is a wholly-owned subsidiary. The blister as received contains from 0.50 to 1.50 per cent Ni, and in this respect differs from that treated by other refineries on this continent. During the anode-furnace treatment, only a portion of the nickel content is removed, and of the amount remaining in the anodes a varying percentage is found in the anode slimes. This necessitates a more extensive treatment than ordi-nary, nickel-free material. Sometimes it is necessary to repeat roasting and leaching operations several times before the nickel content is low enough to permit the slimes to proceed to the doré furnace. This, besides increasing treatment charges, causes greater selenium stack losses and involves a longer tie-up of precious-metal values. Therefore this investi-gation was undertaken with the aim of determining the factors influencing the diversion of nickel into the anode sludge. From experience it was known that by keeping the nickel content of anodes at 0.55 to 0.60 per cent maximum a relatively satisfactory slime resulted. One avenue of attack therefore was developing improved elimination in the anode-furnace treatment so that the anode content mentioned above was not exceeded. Another angle was to improve the solubility, during electrolysis, of the nickel constituent in the anodes, thus decreasing the percentage diverted to slimes. It may he mentioned here that nickel dissolving electrochemically and entering the electolyte pre-sents no difficulty from a treatment standpoint. Both of these approaches were studied and are discussed sepa-rately below.

Jan 1, 1938

By E. G. Deane

A METHOD of top slicing has been devised at the Miami Copper Co.'s mine at Miami, Ariz., which differs radically in some ways from the customary methods of top slicing. The area of that section of the orebody in which top slicing is used is about 800 ft. square. The ore, while for the most part soft, is, nevertheless, considerably harder than the capping. The latter is siliceous, seldom containing any clay or other binding material, and breaks into fine particles so that it runs like sand if given the opportunity. Because of these facts, and because the ore is above the average grade of the mine ore, it has been mined by top slicing. Haulage levels are opened up 150 ft. apart, vertically, with two sublevels between at 50-ft. intervals, to facilitate the building of ore chutes. These sublevels are used during slicing for distributing air in the ventilation system. On the haulage level the drifts are spaced on 50-ft. centers, and raises along these drifts are also spaced on 50-ft. centers, except the incline raises as hereafter noted. The raises are cribbed where necessary. Where the wear will be excessive, ¼ -in. iron plates are spiked to the top of every third set of cribbing, for its protection. When top slicing was first used, an attempt was made to carry a slicing face from fifty to several hundred feet long. Timber and other, supplies were brought in through long drifts from an auxiliary shaft. Great difficulty was experienced in keeping these drifts open, the side pressure breaking the posts and the top weight breaking, both caps and posts. Furthermore, the men could not work efficiently while these drifts were .being repaired. The slicing faces advanced irregularly, due to varying conditions, and in many ways the results were not all that could be desired. It was then decided to divide the slicing area into blocks 200 ft. square and this wins later changed to 250 ft. square.

Jan 9, 1916

By H. Vance

In 1932, as in 1931, the East Texas area outside the Gulf Coast exerted ' its influence over the entire petroleum industry. Practically 60 per cent of the oil wells completed in the United States during 1932 were in this area, development being chiefly confined to the East Texas oil field in Upshur, Gregg, Rusk, Smith and Cherokee counties. This East Texas area is geologically an interior salt dome basin, along the western edge of which are located the fault line fields as represented by Mexia and Powell. Production occurs on salt domes in the interior of the basin as represented by Boggy Creek and possibly Van, although no salt has actually been discovered in drilling at Van. Shore line conditions on the east side of this basin along the flanks of the Sabine uplift have been responsible for the East Texas oil field. Many known salt domes in the center of this basin have been tested but as yet have failed to produce oil in commercial quantities. The main producing horizon throughout the area is lowermost upper Cretaceous and is known locally as the Woodbine sand. The East Texas Oil Field Development.—Approximately 6000 producing wells were completed during the year in the East Texas oil field. No accurate estimate of the total initial production of these wells is available because few initial production tests were made as the wells were completed. The writer estimates the average initial production of these completed wells at 2500 bbl. per day while flowing wide open through tubing. Based on this estimate, the total initial production of the wells completed during the year is 15,000,000 barrels. At the close of 1932 there were approximately 9500 completed wells in the East Texas field. Of this number 176 were without pipe line connections. The oil produced from these unconnected wells could be marketed for $0.30 per barrel while the price paid for oil run from the connected wells was $0.75 per barrel.

Jan 1, 1933

By Charles Hawes

WHEN sulfur is encountered in objectionable amounts, it is regarded as the most trouble-some element for the mine operator to control. It exists in two conditions in iron ores, as sulfide in iron pyrites and as sulfate in gypsum and barite. The sulfate radical (SO,) may also be linked to one or more of the several other elements found in the iron ore compound. The only dependable method for the de-termination of sulfur, particularly when found in the insoluble residue, has been the so-called fusion method. This is a long and tedious process involving several hours for its completion. In looking for a more rapid method which would be .applicable to all iron ores, the writer investigated the work of M. Groger1 who in 1881 showed that by heating pyrite with iron out of contact with air, the pyrite is reduced to iron sulfide and from the latter all of the sulfur will be given off as hydrogen sulfide gas on treat-ment with hydrochloric acid. FeS2 + Fe = 2 FeS FeS + 2 HCl = FeC12 + H2S In 1891 F. P. Treadwell2 not only confirmed the results of M. Groger but also found that iron powder would reduce to sulfide the sulfate radical of any substance, including barite, if not found in excessive quantities. The writer found this to be true and developed a method, in cooperation with F. J. Baker, chief chemist, mining department, of the Cleveland-Cliffs Iron Co., Ishpeming, Mich., for the determination of sulfur in iron ores which is not only very rapid but also accurate. Pure iron ore powder, reduced by hydrogen, gave good results but was found to be very slow in reacting. A high silicon iron with a low sulfur content of 0.012 per cent was found to be. much more active than the pure iron and gave excellent results.

Jan 11, 1927

By H. J. Wasson

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

Jan 1, 1933

By S. R. Elliott

THE Spies mine is located in the eastern half of the northwest quarter of section 24-43-35, near the village of Iron River, Mich., and is operated by The Cleveland-Cliffs Iron Co. Speaking generally, the jasper hanging walls of most of the deposits in the Iron River district dip at a steep angle and are exceedingly strong, standing without caving, even after mining has been continued for years and after large excavations have been made. The ore is fairly hard and tough and contains no slippage faces. It occurs in large masses, which are often egg shape, with the smaller end down, and can be mined in, open stopes without the use of timber. The common system employed in the district is the shrinkage stope, or some modification of it. The Spies system was developed to utilize the advantages of the open-stope method and to avoid the disadvantages of the shrinkage stope. The Spies shaft was sunk to such a depth that the bottom, or third level, was in rock at a short distance below the bottom of the orebody, the shape and extent of which had been previously determined by diamond drilling. This is shown in plan and by the ore contours at the first, second, and third levels in Fig. 1, and in section in Figs. 2 to 7. In order to provide the necessary mills and raises, three parallel crosscuts were driven on 25 ft. centers on the bottom level. Drifts on the second and first levels were driven to the orebody and followed the foot wall in a southerly direction to the end of the ore. In crosscut 3, Fig. 1, raises 30, 40, 50, and 60 were carried up on the foot wall and holed into the second level, and were ultimately carried up and holed into the first level. These foot-wall raises carry the pipes and ladders, provide a means of ventilation, and furnish safe communication to all working places in the stope.

Jan 3, 1922

By R. G. Knickerbocker, A. G. Starliper, H. Kenworthy, C. H. Gorski

This report describes the progress made in the research work on the development of a new method for preparing lower-cost titanium tetrachloride and preparing titanium oxide pigment. One of the requirements for the commercial production of ductile titanium in the process used by the Bureau of Mines is a source of lower-cost titanium tetrachloride. The production of ductile titanium by a modification of the Kroll1 process, recently developed by the Bureau of Mines, requires such a source of lower-cost titanium tetrachloride to make it commercially feasible. This report describes the progress of work done at the Mississippi Valley Experiment Station at Rolla, Missouri, on the development of a new method for preparing titanium tetrachloride. During the course of this research a new method for preparing pigment-grade titanium oxide was developed. At present, the price of technical-grade titanium tetrachloride is $0.32 a pound, which makes the price of the contained titanium $1.28 a pound.2 In addition, the titanium tetrachloride must be purified further before it is suitable for processing into metal, thus making its cost still higher.3 There were 8,562 tons of rutile produced in the United States in 1947, which was 900 tons in excess of that consumed. In addition there were 13,937 tons in various stocks, exclusive of the stocks in the Government strategic stock pile. No estimates of the domestic production of rutile are given for any of the prewar years. However, in 1939, 442 tons of rutile were imported as compared to 14,307 tons in 1947. One of the reasons for the large increase in the production of rutile is the working of the Florida beach sands for ilmenite, during which a considerable amount of rutile is produced as a by-product. It would be of value to determine methods for utilizing the excess production of rutile. The Arkansas titanium deposits in Hot Spring County produced commercial-grade rutile concentrates from 1933 to 1942. These were sold mainly to England, Germany, and Russia.

Jan 1, 1950

By Carl H. Unruh, D. L. Katz

Experimental data are presented for hydrate formation conditions for gas mixtures of carbon dioxide and methane. Equilibrium constants for carbon dioxide, defined as the mole fraction of carbon dioxide in the gas phase (dry basis) divided by the mole fraction of carhon dioxitle in the hydrate (dry basis)... were calculated usine the equilibrium constants for methane developed in an earlier paper. INTRODUCTION A series of papers have been written on gas hydrates, giving temperatures and pressures at which hydrates would form.2. 3, 4. 5, 6. 9. 12, 13, 15 Vapor-solid equilibrium constants have been developed for methane, ethane, propane and iso-butane' by which it is possible to compute for a specific gas mixture the temperature and pressure at which hydrates will form. Carbon dioxide is present in many natural gases in concentrations usually from 0.1 to 2.0 per cent. It also forms a gas hydrate with water and presumably enters the solid solution when present with a natural gas which is forming a hydrate. The equilibrium constant giving the ratio of the concentration of carbon dioxide in the gas phase to the concentration in the solid phase is required for including the effect of the carbon dioxide when computing the conditions for hydrate formation. Direct determination of the concentration of carbon dioxide in solid hydrate requires a difficult separation to be made. Therefore, this research resorted to the measurement of the temperature and pressure at which specific mixtures of methane and carbon diox- ide would form hydrates. From the equilibrium constants previously mentioned for methane, it is possible to compute the equilibrium constant for carbon dioxide, without measurement of the composition of the solid phase. Fig. 1 shows the conditions at which methane and carbon dioxide form hydrates. The methane curve FG extents to some high pressure while the carbon dioxide curve AB intersects the vapor-liquid water-liquid carbon dioxide

Jan 1, 1949

By Carl H. Unruh, D. L. Katz

Experimental data are presented for hydrate formation conditions for gas mixtures of carbon dioxide and methane. Equilibrium constants for carbon dioxide, defined as the mole fraction of carbon dioxide in the gas phase (dry basis) divided by the mole fraction of carhon dioxitle in the hydrate (dry basis)... were calculated usine the equilibrium constants for methane developed in an earlier paper. INTRODUCTION A series of papers have been written on gas hydrates, giving temperatures and pressures at which hydrates would form.2. 3, 4. 5, 6. 9. 12, 13, 15 Vapor-solid equilibrium constants have been developed for methane, ethane, propane and iso-butane' by which it is possible to compute for a specific gas mixture the temperature and pressure at which hydrates will form. Carbon dioxide is present in many natural gases in concentrations usually from 0.1 to 2.0 per cent. It also forms a gas hydrate with water and presumably enters the solid solution when present with a natural gas which is forming a hydrate. The equilibrium constant giving the ratio of the concentration of carbon dioxide in the gas phase to the concentration in the solid phase is required for including the effect of the carbon dioxide when computing the conditions for hydrate formation. Direct determination of the concentration of carbon dioxide in solid hydrate requires a difficult separation to be made. Therefore, this research resorted to the measurement of the temperature and pressure at which specific mixtures of methane and carbon diox- ide would form hydrates. From the equilibrium constants previously mentioned for methane, it is possible to compute the equilibrium constant for carbon dioxide, without measurement of the composition of the solid phase. Fig. 1 shows the conditions at which methane and carbon dioxide form hydrates. The methane curve FG extents to some high pressure while the carbon dioxide curve AB intersects the vapor-liquid water-liquid carbon dioxide

Jan 1, 1949

By Harry Roeser

Short cuts for determining the constants of oil decline curves, with the method of least squares as a starting point, are presented and applications made to practical examples. The nature of the raw data does not justify rigid adherence to the orthodox theory but does lend justification to convenient methods of approximation within reasonable limits. If the conventional form y = kxn were changed to y = k(x + c)', methods of determining the curves would be simplified and greater uniformity in calculated results would probably follow. As A result of the publication, several years ago, of some articles on determining the constants of empirical formulas, the determining the constant's of types of curves used for estimating the production decline of oil wells was brought to the writer for study. Methods requiring a minimum of time and labor and a maximum of rigor were sought, as it appeared that the nature of the data from which such curves are computed and the relative uncertainty of occurrence of the events predicted from them did not justify close adherence to the theory on which the solution of such problems is ordinarily based. The technical deficiencies of the solutions presented in this paper, from the standpoint of the method of least squares, are readily apparent to those familiar with that method, but their presentation in detail here is irrelevant to the subject matter. However, it is the author's conviction, after a rather exhaustive study of the problem, that the value of the solutions lose little by the approximate application of the conventional theory. It must be understood by those who use these formulas that the solutions herein given, and the formulas based on them, are merely facilities to aid the valuation engineer in forecasting future events. It is assumed, also, that before application is made of them, prescient judgment based on the circumstances in each case, shows that the forecast has some probability of realization. On this basis only will these formulas be found useful.

Jan 6, 1924

By Benjamin S. Lindsey, James Norman

BARITE (BaSO4) is the most important industrial barium mineral from the standpoint of quantity consumed. In 1938 the amount was 365,000 tons. Its uses are numerous, some of the more important being in the production of pigments, as an inert filler in a wide variety of products, as a weighting material in oil-well drilling muds, in the manufacture of some kinds of glass, and in the production of barium chemicals. The barite studied in this investigation occurs as the massive variety in a shale replacement formation near Magnet Cove, Ark. It is intimately mixed with quartz and small amounts of iron oxide and residual shale. Complete liberation of barite and quartz is not obtained when the rock is ground to 100 per cent through 325mesh. The crude rock with which all test work was done assayed 85.1 per cent BaSO4, 11.11 per cent Si02, and 2.85 per cent R2O3. Its specific gravity was 4.03. It was found in the course of the investigation that the barite contained a small amount of uniformly distributed carbonaceous material, so intimately dispersed that it could not be seen with the microscope, but gave a definite gray cast to the barite concentrates. The color of the barite in polished sections of the crude rock ranged from gray to almost black, while finely ground powder was a reddish gray. The reddish hue was due to the iron oxide present. In 1939, under the supervision of Oliver C. Ralston,* the Bureau of Mines, in cooperation with the Milwhite Company, of Houston, Texas, undertook to study the flotation of barite from Magnet Cove, Ark. Flotation of several southern barite ores had already been investigated by the Bureau of Mines.1 The Magnet Cove barite was unique, however, in that it had to be ground to such an extremely small particle size for liberation. The flotation of nonmetallic minerals in the presence of a large amount of slime is usually very difficult, and when done is an innovation calling for conditions different from those under which granular material is separated. LABORATORY FLOTATION WORK Preliminary investigation showed that the flotation reagents recommended by O'Meara and Coe1 for separating barite and siliceous material were suitable, but much larger quantities of reagents were required to separate such finely divided material. Moreover, it was found that careful control of the frothing was necessary. When oleic acid and sodium silicate were used a voluminous froth was observed at the beginning of a test, and toward the end there was not enough froth to effect complete recovery of barite. The addition of pine oil as a frother gave proper frothing for the duration of the test, and the substitution of coconut fatty acid (crude lauric acid) for oleic acid produced a more heavily burdened froth. Two different paper-mill fatty-acid products were tested

Jan 1, 1941

By H. Brandhorst, C. G. Dunn

THE main purpose of the present note is to provide further information on the effect of orientation on strain-induced grain boundary migration in sheet material. A secondary purpose is to draw attention to the presence of a possible (hkl) dependent surface energy driving force, when the two grains of a bicrystal specimen have different (hk2) planes at the gas-metal interface, and to suggest means of eliminating this effect from the strain effect. If two grains A and B of a bicrystal have specific surface energies ? A and ? B respectively, there exists a driving force for grain boundary migration equal to 2(? B - ? A)/t, where t is the thickness of the specimen.' When t is quite small and the residual strain energy densities €A and €B of grains A and B, respectively, adjacent to the boundary are nearly equal, it is possible that the surface effect may be larger than the strain effect. he difference € B - € A gives a driving force per unit area of grain boundary due to an applied strain.)2 However, with increasing t the surface effect decreases while the strain effect presumably remains constant. Therefore, at some sufficiently large value of t, it is possible to ignore surface energy driving forces.* On the other hand, the surface effect is eliminated for all value of t when both grains have the same (hkl) orientation or have identical values of surface energy. Although the previous study provided information on the effect of orientation on strain-induced erain boundary migration,' no orientations with the (100) plane in the plane of the sheet were included. The present paper provides information of this kind. A seed crystal reorientation technique4 was used to prepare a large bicrystal of silicon iron (3 1/4 pct Si) consisting of two (100) grains in the (100) [001] and (100) [Oil] orientations. After a cold rolling strain (7 pct reduction to 3/4 mm final thickness), small specimens were prepared as before2 and then annealed in hydrogen. The boundary migration was such that the grain in the (100) [011] orientation always grew. After overnight anneals at 1100° or 1000°C, none of the initial (100) [001] grain remained. An anneal of 30 min at 950°c, however, provided information on the start of boundary migration. Fig. 1 shows both the initial position (lower line) and the final position (upper curved line) of part of the boundary, as revealed by thermal grooves. In a different area, part of the final boundary was not revealed by thermal grooves; the rate of boundary migration presumably was too high for the growth front to be defined by the time dependent thermal grooving process. In another area there was a vacated intermediate position connected to the initial position of the grain boundary. This indicates that only part of the boundary

Jan 1, 1962

By C. A. Shook, W. H. W. Husband, D. B. Haas

Introduction Although previous studies1,2,3 have been made, no correlations for pressure drop have been proposed. This is probably because severe particle breakage occurred and pressure drops changed substantially with time. A quantitative statement of the relationship of pressure drop to the parameters of the system is desirable for lignite since, unlike higher rank coals, lignite slurries are thixotropic. The present investigation was undertaken to quantify the pipeline behavior and required continuous monitoring of pressure drop and size distribution.

Jan 1, 1980

By Michael J. Klishis, Daniel K. Thomas

This paper describes and evaluates factors to be considered in applying computer based instruction (CBI) to the mining industry. CBI is especially suited to the monitoring of training functions and to the delivery of competency-based task training. Its effectiveness is dependent upon: (a) organizational factors (size, number of trainees and trainers, and current training budget), (b) appropriate hardware (accessibility, exclusivity, user-sophistication, transportability, graphics, and cost), and (c) appropriate software (flexibility, response evaluation, video interaction, graphics, and trainee management).

Jan 1, 1983