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E. S. MOORE (author's reply to discussion*).-I have read with much interest Dr. W. F. Smeeth's criticism' of my article on the air blasts in the Kolar Gold Field, India. However, before answering the questions he asked, I should like to suggest that possibly the phrase "difference of opinion" might be substituted for the word "misapprehension" when applied to my statement that the matrix of the conglomerate resembles a hornblende schist. This conglomerate is certainly regarded as a metamorphosed sediment. Dr. Evans, who has had wide experience with metamorphic rocks, has regarded this as a clastic rather than an autoclastic rock and mentions it as a probable glacial deposit2 and similar to the Lower Huronian conglomerate of North America. I was greatly impressed by the similarity between this rock and the bands of Huronian conglomerate in the United States and Canada where metamorphism has rendered the matrix of the rock schistose. It was scarcely intended that the word basal, as used in my text, should be extended to the Kolar field, although possibly it may be equally applicable there. The word is so frequently used on this continent for the Lower Huronian conglomerate, which in many places is the basal formation of the predominantly sedimentary Proterozoic group, overlying the more largely igneous Archeozoic rocks, that it was inadvertently used without special stratigraphic significance for the Kolar area. In reply to Dr. Smeeth's question as to how the conglomerate indicates a syncline, it would seem that if there is present in a closely folded area a band of sediment that is younger than the surrounding rocks, it must be in a syncline in those rocks. As to an apparent contradiction in the statement on page 693 regarding the compressive stress, it does not seem that such contradiction exists; I think every one will take the same meaning as Dr. Smeeth has taken, which is exactly what was intended.

Jan 12, 1918

By WALDEMAR T. SCHALLER, EDWARD P. HENDERSON

THE material available for mineralogic study, consisted of drill cores, 2 to 3 in. thick, supplemented by small well cuttings. Such study has added no essential new information regarding the minerals, though the refractive indices, used for determinative purposes, have been determined more accurately than before, permitting the development of a scheme for the rapid identification of these minerals. The essential points brought out by the investigation are two: (1) that certain mineral associations evidently point the way to an understanding of the geologic history and (2) that a definite sequence of mineral formation has taken place so that the original minerals formed have been in part-reacted on producing new compounds and associations; Twenty minerals have been found. The most important are :

Jan 1, 1929

By Stanislaus Skowronski

THE melting of cathode copper, usually containing 99.98+ per cent. Cu, would appear to be a simple matter. Owing to the well known affinity of copper for sulphur, however, so much sulphur is absorbed by the copper during the operation that a long and expensive refining process is required to remove it, and the final product is inferior in purity and lower in electrical conductivity than the original cathode copper. The furnace operation, as now conducted, includes the following stages: 1. Charging the cathodes into the furnace. 2. Melting the cathodes. 3. Oxidizing period-saturating the copper with cuprous sub-oxide and bringing the metal to the condition known as "set copper;" this is now done by blowing air into the molten bath of metal. 4. Reduction period, otherwise known as "poling," whereby the oxygen previously added is removed by covering the molten bath completely with coke or charcoal and introducing large poles of green wood; this reduces the cuprous sub-oxide, bringing the copper to the "tough pitch" stage ready for casting. 5. Casting Period. Many experiments have been made to obviate the long periods of oxidation and subsequent reduction, with no success. While the copper first, cast will be good, as indicated by the set surface of the bars, it is impossible to hold it to the "tough pitch" condition, and long before the whole charge has been poured the copper will become "overpoled," entailing numerous difficulties. Sulphur has always been blamed by the furnace men as the reason why this refining process is necessary, yet the literature on the subject does not sufficiently emphasize how small a proportion of sulphur will ruin copper for practical purposes.

Jan 3, 1918

By K. L. Meissner

It is well known that the so-called pure aluminum contains noticeable amounts of impurities, chiefly iron and silicon, and many investigators have studied the forms in which these impurities exist. Hanson and Archbutt1 state that iron exists in aluminum as FeA13 and silicon as elementary Si. The solubility of FeA13 in solid aluminum is practically zero, or at least so small that the smallest trace of this compound is always visible as a separate constituent. Under the microscope an untrained eye can hardly distinguish, without etching, the two constituents FeA13 and Si, but they can be differentiated by suitable etching reagents. Anderson2 also found the same results. At the same time, Merica, Waltenberg, and Freeman3 found a constituent of unknown composition. They found a small thermal effect, at 610" C., on the cooling curves of aluminum with small amounts of iron and silicon. The intensity of this effect increased with increasing silicon content, until an effect occurred at 576" C. due to the eutectic between aluminum and silicon. The authors ascribed the effect at 610" C. to a compound, which they call "X constituent." It was thought to be a ternary compound containing iron and silicon and could be observed under the microscope as dark particles. Dix4 has published unetched photomicrographs of an aluminum with 0.51 per cent. iron, 0.99 per cent. silicon, and 0.32 per cent. copper that shows three constituents: the dark Si (black in the figure), the lighter FeA13, which appears in half tone and crystallizes in needles, and a constituent of the same color as FeAL3 but of different crystal form, often resembling Chinese script. This last constituent, Dix thought, is a compound of Fe and Si; not the compound FeSi but a compound containing a relatively small amount of silicon. Therefore an alloy of aluminum. iron, and silicon (the copper should not be regarded in the following considerations) must contain the following four constituents: Al, FeA13, Si, and a compound of Fe and Si. This, however, does not agree with the laws of chemical equilibrium.

Jan 1, 1926

By A. F. Lucas

Introduction BELLE ISLE, located in the low sea marshes near Atchafalaya Bay, is the southeasternmost of the famous Five Salt Islands of Louisiana. Rising about 80 ft. (24 m.) above the level of the surrounding marsh and being some 800 acres (323 ha.) in extent, it constitutes a striking landmark on the low Gulf coast, and since the eighteenth century, when it played an important part in the operation of the buccaneers, it has been intermittently frequented by man. In 1897, the writer discovered the great mass of salt that underlies the island and shortly afterward pub-lished a brief account of the geology of Belle Isle and the neighboring salt islands.' In that paper he described principally the salt, but pointed out also the occurrence of petroleum and of sulphur in the strata above the salt. Since that time the island has been extensively explored by the drill, and the developments up to 1908 have been described by Veatch2 and Harris," and Knapp.4 The writer's early conclusions as to the probable presence of sulphur in considerable quantity have been confirmed by the later drilling, some of the wells having found quantities of gas containing sulphur dioxide and a number of sulphur-bearing strata as well. Under the stimulus of the present keen demand for sulphur for war purposes, a syndicate of New York capitalists was recently formed to explore the sulphur resources of the island in more detail. Under the writer's direction, six wells were drilled for this syndicate during the winter of 1916-17. The present paper presents briefly the results of this work and sums up the present knowledge of the geology of this highly interesting locality.

Jan 9, 1917

By John H. Smith

Because of increased pressure from federal and state regulatory agencies, most acid flows will require some sort of treatment prior to being discharged to receiving streams. In many industries, the volumes of liquors are large and their acid content varied. Development of a waste treatment process minimizing equipment cost and utilizing land efficiently is mandatory. Methods of acid neutralization with lime have been known for years, however, the volume and characteristics of the resultant precipitated solids can create a disposal problem. Also, when standard lime treatment is used, the settling characteristic of the precipitated solids is normally slow. In some instances, the necessity of added dissolved solids removal, such as iron, needing aeration, add to the problem of concentrating neutralized solids.

Jan 12, 1972

By Brian W. Mackenzie

Since mineral economics is often coupled with mining engineering in the solution of mineral industry problems, it is important that the principles of this science be a part of the mining engineer's education. Essentially, mineral economics is the application of economic principles to analysis of the multistage process by which minerals are converted from geologic resources to marketable products. In some instances, it may require only the analysis of case studies from a well- developed economics core. In others, however, it requires special skills, because some aspects of the mineral conversion process--such as mineral occurrence, exploration investment and depletion-have no complete parallel in general economics. The mining engineer has been an important contributor to the analysis of mineral economics problems because of his special knowledge of the mineral industry.

Jan 1, 1971

By GEORGE D. RAMSAY

ABOUT three miles west of Fontana San Bernardino County, California, and fifty miles east of Los Angeles, the Kaiser Co., Inc., has built an integrated steel plant. By integrated, I mean that from its wholly owned iron ore and coal supply, the Kaiser Co. is producing in its own mills iron and steel products. Pig iron to meet the West Coast needs has been produced at Fontana since Jan. 1, 1943; steel ingots were first poured there May 14, 1943; and steel plate for ships was first rolled Aug. 15, just sixteen months after ground was broken. Briefly, the plant consists of: (I) Two batteries of by-product coke ovens, totalling ninety ovens, carbonizing about 1740 tons of coal per day at capacity; with by-product facilities for the production of tar, ammonia, and ammonium suIphate, light oil distillates, and tar distillates. (2) One blast furnace producing at

Jan 1, 1944

By A. H. Miller

THIS survey is one of the more recent tests of geophysical methods of prospecting by the Dominion Observatory and the Geological Survey of Canada, of which the purpose is to find out what application such methods may have to geological problems in Canada. The Malagash salt deposit lies on the north shore of Nova Scotia about 40 miles east of the New Brunswick boundary, and forms a part of faulted and folded Carboniferous strata. The salt beds are exposed only in the mine workings, which are about 1000 ft. deep and at one place extend for 1000 ft. along the strike. Lack of rock exposures, complicated folds, and faults make it impossible to predict the location of salt away from the mine. A survey of an area in the vicinity of the mine was therefore undertaken to find out whether the salt could be located by the torsion balance and whether its extension from the mine workings could be traced. As the gravitational effects at Malagash may be fairly typical of those at other concealed salt deposits in the Carboniferous rocks of the Maritime Provinces of. Canada, the survey has a direct bearing on prospecting for other deposits. The survey was made in 1934 by A. H. Miller in collaboration with Dr. W. A. Bell, of the Geological Survey of Canada.. Observations began on June 15 and were completed four months later, on Oct. 15. Definite gravitational effects including a lowering of gravity were observed over the deposit. The survey also disclosed one other area of low gravity east of the mine but whether this area is underlain by a large body of salt is not yet established.

Jan 1, 1936

Two career employees of the US Dept, of the Interior, in a recent study, indicated that by the end of 1974, 73% of all public lands had been entirely or partially closed to exploration and development of essential resources for leasable minerals and 67% had been similarly restricted for locatable minerals.1 This has come about because of the lack of coordination within the executive branch and between the executive and legislative branches of the federal government and without regard for the cumulative, depressing effect on future domestic mineral production. Much of the withdrawn land is felt to have great potential for discovery of significant mineral deposits.

Jan 5, 1976

By G. L. Oldright

THE development of the reverberatory furnace for smelting copper ores up to 1912 was described by E. P. Mathewson1 with details concerning the great changes in dimensions of the furnace. Hayward2 tabulated similar data, giving developments up to about 1924, in his revision of Hofman's Metallurgy of Copper. DEVELOPMENT OF PRESENT SMELTING PRACTICE Dimensions of Furnace Very great changes were made in the dimensions of the smelting hearths of the furnaces in the period from about 1800 to 1906, the length increasing from about 11 to 116 ft., and the width from 8 to 19 ft. During this time the tonnage smelted increased from about 9 to 250 tons per 24 hr., and the tons of charge smelted per ton of coal increased from 0.77 to 4.3. Dr. Mathewson3 noted no great difference in the "fuel ratio" (i. e., the amount of charge smelted per ton of coal) as the furnace at Anaconda was increased in length by stages from 85 to 116 ft. (The percentage of copper in the slag, however, was lowered from 0.42 to 0.36 per cent. The other components of the slag were not given.) Lump coal fired on grates was the fuel used during this period. The practice in operating the furnaces over such a length of time naturally varied considerably, and there were differences in composition and nature of the charge, yet it may be considered that the improvements made were due largely to increases in the size of the furnace used. Doubt-less some credit should be given to improvements in operating technique, like changes in the methods of firing the lump coal. However, the greater part of the advance was probably due to factors influencing the

Jan 1, 1928

By John Tyssowski

IN 1925, Harry Howard Stout, then metallurgist for Phelps Dodge Corporation, while investigating the cleaning of cathode copper by various gases at elevated temper-atures below the melting point of the metal, observed in the laboratory that particles of pure copper heated in a closed tube filled with hydrogen seemingly "stuck together." By further investigation he found that there was actual crystal growth across the boundaries of the particles of pure metal; in other words, there was a complete new crystal realignment and growth throughout the newly formed copper mass. It was coalescence, not adhesion; the several parti-cles had become one unit. From this dis-covery has been developed the coalescence process, whereby copper of cathode purity is squirted out in semifabricated form from an extrusion press, by the appli-cation of about 30c0 tons pressure on a 10-in. piston. Stout decided that cathode copper pro-duced by electrolytic deposition was the logical source of the pure copper required for the coalescence process, but as there was no way of reducing the ordinary tough commercial cathodes to the small particles required he was confronted by a serious problem at the outset. Under his direction, this problem was solved by William H, Osborn and Harry Howard Stout, Jr. They developed the process and technique for producing cathode copper in brittle, friable form, and to them must be given the greater part of the credit for this phase of the development program as well as for that relating to the gas cleaning of the cathode particles.

Jan 1, 1940

By K. Adam

Grinding in steel mills adversely affects the flotation of pyrrhotite. The electrochemical nature of inter action between pyrrhotite and active metals was investigated by contacting pyrrhotite with platinum at different applied potentials. Flotation tests, scanning electron microscopy, Auger electron spectroscopy, and X-ray photoelectron spectroscopy were wed to examine the surface properties of pyrrhotite. The formation of hydroxide or oxide and sulfate species of iron through the oxygen reduction reaction at the cathodically polarized surface of pyrrhotite was shown to be the mechanism responsible for the reduced floatability of pyrrhotite.

Jan 1, 1985

By F. J. Haller

The need for permanent, fireproof support indicated structural steel sets. Experience over the past six years, involving more than five miles of permanent underground openings, has proved that steel is permanent, safer and, in the long run, cheaper than either treated or untreated wood supports. Excavation is reduced, as are installation, transportation, and handling costs. A number of hazards are reduced or eliminated by the use of steel.

Jan 4, 1950

By Paul D. Torrey

The water-flooding of oil sands has been widely practiced for many years in the Bradford and Allegany fields. Its effect upon the production of these fields has been almost phenomenal. In 1907 their estimated production was 3500 bbl. per day; in December, 1929, the combined production is estimated at 33,000 bbl. per day, an increase of almost 1000 per cent. in 22 years. This increase in production is directly attributable to the successful application of water-flooding, which has transformed the fields that were rapidly approaching abandonment into one of the most actively operated regions associated with the petroleum industry, and has made them important factors in the production of Pennsylvania Grade crude oil. The writer is indebted to many companies for information included in this paper. He is particularly grateful to the Sloan and Zook Co., the Petroleum Reclamation Co., George Bovaird, Jr., and the Associated Producers Co., of Bradford, Pa., who have generously made available much valuable data. Owing to the frequently competitive and confidential nature of property purchases, it has not always been possible to make specific reference to individual wells or properties; but wherever feasible, specific references have been made. Economic Factors The successful application of water-flooding for increasing the recovery of oil has been almost confined to the Bradford and Allegany fields. This has been due not only to legal restrictions in other fields and to very favorable sand conditions in the Bradford-Allegany region, but also to certain economic factors which are worthy of consideration. There has been some alarm regarding the effects of the rapidly increasing production upon the oil market but the writer is inclined to believe that future development can be made sufficiently flexible to meet the demand for this grade of oil. There has been a decided tendency toward consolidation of properties by mergers and purchases and, in addition, many of the individual producers are content to take advantage of floods advancing on their holdings from adjoining properties without developing their own on an intensive scale. Cooperative drilling along

Jan 1, 1930

By A. Patton

Introduction THE use of roll scale in the Bessemer process dates back, to the "best of our knowledge, at least 20 years. It was first used by the Ohio Steel Co.; Youngstown, Ohio (now the Ohio Works of the Carnegie Steel Co.) under the direction of Sam, MacDonald, Superintendent of the Bessemer Department at these works. Two 10-ton vessels and one blowing engine capable of blowing one heat at a time were employed. The object of using the scale was to -shorten the length of the blow; or in other words, to increase the production with the same equipment. Various means were tried out for introducing the roll scale into the bath of molten iron: It was shoveled into the vessel before the heat was charged, so that the metal would flow over the scale; it was shoveled into the bath after the vessel was turned up; it Was dumped into the empty iron ladle by the wheelbarrow-load, and at times wars dumped on top of the molten metal in the iron ladle. But the practice of introducing the scale into the iron ladle had to be abandoned on account of danger from explosions and of skulling the -ladles. It was soon learned that the proper place to charge the scale was in the empty vessel, so that when the molten iron was poured into the vessel it flowed over the scale, causing a considerable reaction to take place before the heat was turned up. Eventually, cylindrical chutes similar to those now in use were installed. Into these chutes the scale is dumped and carried into the empty vessel. Before this convenient means of introducing the scale was adopted, the Ohio Works had satisfactorily demonstrated that roll scale would increase production, by blowing 107 heats in one 12-hr. turn (1,087 tons) with one blowing engine, blowing one heat at a time; whereas, prior to the use of scale, the best practice at these works was about 80 heats under the same conditions.

Jan 2, 1917

By A. J. Lynch

There are two factors which are important in the development of automatic control systems for mineral preparation and concentrating processes. They are the availability of accurate and reliable on-line measuring instruments and an understanding of the effects of important variables on process behaviour. The state of automatic control for the different processes depends on the progress which has been made in these areas and this varies considerably. This is illustrated by discussion of four processes, wet ball milling and hydraulic classification, wet autogenous milling, sulphide flotation and dense medium separation in coal preparation plants. In each case the process characteristics, current control practice and future developments are discussed. Particular problems which have delayed progress are discussed.

Jan 1, 1984

By Valentin R. Garfias

The world's production of petroleum during 1926 is estimated at 1,096,000,000 bbl., an increase of about 29,000,000 from that of 1925 and somewhat larger than the average during the last 4 years, which is about 1,049,000,000 bbl. The daily average during the year may be estimated at 3,000,000 bbl. of which the United States produced 2,123,000 and other countries 877,000. The outstanding developments during the year have been the decline of the Mexican fields, the counterbalancing of this decline by the increase in Venezuelan and Russian production, and increases in Roumania and Colombia. During 1926 the United States, Mexico and Russia retained their relative positions as the three leading producers, while Venezuela probably outranked Persia for fourth place, Roumania passed Dutch East Indies for sixth, and Colombia moved from sixteenth to the eleventh position. It further appears that should present conditions develop normally throughout 1927, it is not improbable that Mexico will be outranked by Russia as the second oil-producing country and that the increased yield of Colombia will place this country in the eighth or ninth position, and ahead of India. The United States and Mexico should produce in 1926 about 79 per cent. of the world's total and the aggregate of the seven leading countries should be close to 95 per cent. of the total. It is interesting to note that about 85 per cent. of the total comes from fields on the American continent, the United States accounting for about 71 per cent., and Spanish-American countries and Trinidad for 13 per cent. Production of countries other than the United States and Mexico has gradually increased during the last four years and now represents about 21 per cent. of the total. The United States easily retains its long standing leadership with a total yield of 775,000,000 bbl., or an average daily yield of 2,123,000, representing about 71 per cent. of the total, which is about equal to that of the previous year. An increase in production of about 11,000,000 bbl. is indicated by the statistics so far available. It will be noted that the American production in the last 4 years has averaged about 746,000,000 bbl. yearly and that this uniformity, as well as the marked increases

Jan 1, 1927

By John V. Beall

They let the whole world know again that not only could we do it, but we make it look easy. The great crews before Scott, Irwin and Worden of Apollo 15 have all blended warm humor, informality and dexterity to put on a good show: but it keeps getting better and the last one was the best. Scott's rendition of Galileo's experiment using a hammer and a feather--not just any feather, but a falcon feather after the name of the LEM-was priceless. One generation of school kids will never forget that lesson. The final touch was in the "would-you-believe''" category, Now if English astronauts had been performing the mission, the sign-off would have been typically low key. Something like; "well its tea time, chaps; we'll have to toddle along." Apollo 15 surprised and thrilled spectators by blasting off to the Air Force song "Off we go into the wild blue yonder" and leaving a camera behind to photograph their own ascent. Now that is what we call showmanship. There is another aspect to our space show and that is that it cost billions of dollars to put on. With that kind of backing, the world for an audience and in the face of grave personal risk, one would expect the space explorers to be all business. Instead they did their jobs with limpid buoyancy. Our older readers will recall and contrast a movie of the thirties and the tense atmosphere when they had to talk that kid up there (Franchot Tone) down through the zero ceiling. A feat of considerably less difficulty than docking LEM. but nevertheless the gut tightening drama was absent in the latter event. In another example, few of us can visualize reporting back after a business mission to one of the old barons such as J. P. Morgan in any but the most sedate and business-like terms. In fact we don't have to go that far back, as we can think of a few pepper-pot bosses we have had to whom one always played it straight.

Jan 1, 1971

By J. E. Papin

MORENCI ores contain as an average about 0.015 pct molybdenite, MoS2. Incidental to the concentrating operations applied for the recovery of copper minerals, approximately two-thirds of the molybdenite is floated and appears in the final copper concentrate. The economic importance of molybdenum and the success achieved in its recovery in milling operations elsewhere encouraged research directed toward its recovery in marketable form. Several procedures are utilized to effect separation of molybdenite from copper and iron sulphides, but only two have wide application. In the better known of these two methods the molybdenite in the copper concentrate is depressed in a flotation operation using soluble starch as the depressant. The tailing from this treatment thus becomes a low-grade molybdenite concentrate which after thickening, filtering, and low temperature roasting is repulped with water and subjected to additional flotation steps for recovery of the molybdenite. A thio-phos-phate collecting agent is employed in flotation of the copper minerals. Presumably the stability and lasting effects of that collector type necessitated the practice of depressing molybdenite followed by subsequent roasting to insure elimination of copper and iron sulphides from final molybdenite concentrate. The second important method of recovery is applied at various southwestern plants. In those plants xanthates are in use as copper collecting agents. It has been found that xanthates are relatively unstable and their collecting power for sulphides is destroyed by very simple procedures. The method generally applied is to subject the xanthate-acti-vated concentrate, in the form of a pulp, to prolonged heating using steam as the heating medium. A concentrate thus treated may then be subjected to a flotation operation for recovery of the molybdenite, using mineral oil collecting agents, and the copper and iron sulphides will be depressed. Neither of the above processes was applicable to Morenci concentrates. Morenci uses a thio-phos-phate collecting agent in its flotation operation. However, it was established that soluble starch was not a depressant for Morenci molybdenite; therefore the first step in that process was not applicable. AS would be expected the copper and iron sulphides in Morenci concentrates could not be depressed by the heating methods used on xanthate activated concentrates. Low-temperature roasting did eliminate the effects of the thio-phosphate but had to be rejected as uneconomic in as much as the tonnage of concentrates involved was too great. Preliminary research having established the above facts, it became obvious that new methods would have to be developed for the recovery of molybdenite from Morenci concentrates. A broad laboratory investigation was initiated along two general lines, both directed toward depression of copper and iron sulphides. One approach was through the use of water-soluble oxidizing agents with the objective of destroying the thio-phosphate in the concentrate and thus eliminating its collector effect. The other approach involved the use of soluble sulphides, which have long been recognized as sulphide depressants. These efforts resulted in laboratory processes which showed promise. Research was then extended to a pilot plant having a daily capacity of several tons of concentrate. This operation soon demonstrated that soluble sulphide—basically sodium polysulphide—when applied to a pulp made slightly acid with sulphuric acid, proved to be the most effective sulphide depressant. The rate of concentrate treatment in this plant and the low molybdenite content of the concentrate prevented carrying the process to a conclusion, namely, production of molybdenite concentrate of marketable grade. Laboratory treatment of pilot plant concentrate indicated that a marketable product could be made from it, given a tonnage suited to available cleaner flotation machine capacity. Accordingly, the molybdenite plant was enlarged to permit treatment of the total copper concentrate from the extension plant, maximum of approximately 800 tons per day. In the enlarged plant a major difficulty was encountered. No criteria could be established as a basis for control of the process. In the early stages of flotation, because of the small amount of molybdenite involved, there was no visual evidence of the relative floatability of molybdenite with respect to

Jan 1, 1956