Search Documents

By A. E. Wells

In this paper are described various comparative tests made on cracked and straight run gasolines. The results of these tests may be briefly summarized as follows: Samples of 54 to 55° Bé. gravity cracked gasolines, with end point of about 442° F., and with a somewhat larger proportion of the less volatile fractions than conformable to government specifications, were used in a single cylinder variable compression engine under the same conditions as were samples of straight run gasoline of 58 to 59° Bé. gravity, and of which one had a greater proportion of the more volatile fractions than called for in government specifications. The cracked gasolines showed decidedly less tendency to knock, hence could be used at higher compression ratios and thereby developed from 10 to 20 per cent. more power than did the straight run gasolines. These figures may be taken as one measure of the superiority of the cracked gasolines under test with the straight run gasolines. It is not claimed that all cracked gasolines are superior to all straight run gasolines to the extent indicated by the above tests; cracked gasolines vary as do the straight run products. Cross's work and that of others have indicated that certain cracked products may have a much greater superiority over straight run than that determined above. From various sources and by different methods of testing data are being obtained to show the definite and generally quite considerable superiority, as an anti-Cetonating fuel of cracked gasolines over straight run gasolines. It is now becoming generally recognized that by increasing the production of cracked gasoline motor fuel from those heavier petroleum fractions, which otherwise would be used for burning purposes, the petroleum industry is not only working in the interest of the conservation of the world's supply of petroleum, but is at the same time making available to the gasoline-consuming public a product distinctly superior to the straight run gasolines.

Jan 1, 1927

By Frank Firmstone

WE found it necessary, in December, 1874, to repair the upper part of the lining in No. 5 furnace at Glendon, and, as we succeeded in doing it with comparatively little trouble, a description of the plan followed may be of service to those having a similar operation to perform. On two opposite sides, as shown by the sketch, the lining was completely gone for a height of about four feet, below which it increased gradually in thickness, being nine inches thick about three feet lower down. On a plane at right angles to the section drawn, the brick were nowhere entirely gone, but were in some places not more than two or three inches thick, being still sufficient to sustain the upper part, where the brick, being above the level of the stock, were not at all worn. The furnace was blown down, so that when we cast and closed the tuyeres, about 7 A.M., on December 8th, the top of the stock was about twenty-four feet below the filling-plates. The walls were quite hot, and a good deal of gas was given off for several hours after the tuyeres were closed. The hopper and bell were thrown into the furnace, and were covered by filling several charges of cold stock over them, which at once greatly cooled off the top of the furnace. A wrought-iron pipe, thirty inches in diameter, in five sections, each six feet long, was then put down, and made to stand upright, as nearly as possible in the centre of the furnace. Around this we filled a double charge of coal, taking care to heap it up next the pipe, and let it get thinner as it got to the walls. This was covered with about two feet of fine ore, leaving the lowest joint in the pipe entirely uncovered. We were now ready to put in our scaffold to get at the

Jan 1, 1876

By R. S. Shoemaker, F. W. McQuiston

MAGMA COPPER COMPANY San Manuel Division The San Manuel Division of Magma Copper Company is located about 40 miles north of Tucson. Tons of ore milled in 1973 .were approximately 19 million at a rate of 63,000 tons per day. From this, about 42,600 tons of copper concentrate was produced as saying approximately 1.070 MoS2 and 28.5% Cu. As with many copper ores, the San Manuel ore contains a small amount of gold, but in this particular case, much of the gold follows the molybdenite. Separation of the molybdenite from the bulk sulfide concentrate by flotation produces a moly concentrate containing 9170 MoS2, just under 1.070 Cu, and 0.44 oz Au per ton. Cyanidation of this material for gold recovery is the only practice of its kind known to the authors of this Monograph. After thickening, the final moly concentrate is filtered for subsequent repulping with cyanide and lime. Gold dissolution takes place in three agitators in series with the pulp from the agitators being filtered in two stages in disc filters. Between filtration stages, the cake is repulped with barren solution. Filtrate from both filters is the pregnant solution. The Merrill-Crowe recovery unit is comprised of two solution tanks and the usual clarifying filter, vacuum tower, zinc dust feeder and Merrill precipitate press. Because of the presence of finely divided sooty chalcocite in the molybdenum concentrate, the cyanide consumption of 55 pounds per ton is extremely high. A compensating factor, however, is the low copper, moly concentrate produced. Precipitation of the gold from the highly copper-contaminated solution requires 0.56 pounds of zinc dust and 0.28 pounds of lead acetate per ton, high figures when compared to normal cyanidation practice. The Merrill- Crowe precipitate assays approximately 28.5% Cu, 8% Zn, 156 oz Au and 197 oz Ag per ton. The San Manuel cyanidation plant is an outstanding and innovative development.

Jan 1, 1975

By Leon McCulloch

WHEN clean iron and metallic zinc dust, protected from the air, are heated below the melting point of zinc, the iron takes on a coating that has excellent protective value. This coating is a brittle alloy of zinc and iron, and the process is called sherardizing. Although the zinc particles are covered with oxide and cannot touch the iron, an extremely small amount of the zinc vaporizes and the vapor, reaching the iron, alloys with it. Other zinc then vaporizes to replace that which has been removed from the atmosphere. This process continues indefinitely at a decreasing rate, for the coating already formed permits zinc to diffuse through-it to combine with the iron beneath. In this way, the coating grows outward from the surface of the iron, as the bark grows from a tree. The method of growth was clearly seen while sherardizing small cubes of cast iron, at about 450° C., in a small glass-stoppered bottle enclosed in a rotating drum. The dust contained about 3 per cent. iron, which prevented caking, and coatings 1/2 in. thick were grown in a few hours. After a heavy layer had been formed, the cubes were again: treated for a shorter time. The layer last formed was seen to lie next to the iron, instead of at the outer surface, showing that the growth was from the surface of the iron outward. The coatings split at the edges and corners, leaving the iron exposed there. Flakes of graphite from the iron were lifted upward and embedded in the coatings. The composition of sherardized coatings varies from the outer surface inward, as would be expected from the mode of growth. That is, the iron content increases slowly at first, then more rapidly as the iron is approached. At the surface the least amount of iron possible is 6 per cent., as the experiments described below have shown.

Jan 2, 1922

Hugh M. ROBERTS,* Minneapolis, Minn. (written discussion ? ).¬The paper by Messrs. Hall and Row marks a distinct advance in the art of diamond drilling, because it records a systematic-application of a method for directing the path of the diamond bit. Their work is an admirable example of engineering development. They had a definite object to attain; i.e., the drilling of many vertical diamond-drill holes to depths of 2500 or 3000 ft. (762 or 914 m.). They availed them-selves of a method of wedging seldom used, improved the manner of making the wedges, developed a technique of survey, and put the process into practical, continuous operation. So effectively has this been done that they determine the average cost of the work. The publication of the results, in the form of detailed diagrams, makes the application general to whoever has a similar problem. The wedging of diamond-drill holes has been practised in the Lake Superior region for the purpose of making branch holes, particularly where the original hole has penetrated a great thickness of glacial drift. The uneven nature of the iron formations has caused the results to be somewhat uncertain. One operation, in 1907, near the American mine on the Marquette Range, by the firm of Longyear & Hodge, predecessors of the E. J. Longyear Co., resulted in the drilling of a hole 1828 ft. (557 m.) deep, with two branches at depths 100 ft. (30 m.) and 770 ft; (234 m.), respectively. A second hole from the same set-up went to a depth of 2497 ft. (761 in.) with a branch at 185.0 ft. (563 m.). In this instance, the wedges were forged to the desired shapes and angles with respect to each other. A drill hole, sunk in 1915,. in the township of Bates in the. Iron River district of Northern Michigan, which penetrated 385 ft.

Jan 11, 1919

By E. A. Stephenson

In spite of tremendous handicaps notable advances in production engineering have been achieved during 1932. The technique of deep well drilling has continued to progress, notably in California and at Big Lake, Texas. In the latter field a method has been devised by which two grades of oil in contact with each other are produced without intermingling. In rig design many improvements have been made whose objective is to facilitate deep drilling with reduced power losses and increased life of the equipment. Flush joint casing and drill pipe have been improved further, careful tests indicating that the drilling time can be reduced by from 5 to 20 per cent where flush-joint pipe is used. Slow-speed pumping has come into wider use, with further increases in over-all efficiencies. A number of improved well pumps also have been developed and are being tested. One of the most important of these is a positive displacement pump of the rotary type, directly connected to an electric motor placed in the bottom of the hole, and adaptable to various sizes of tubing and casing. In some localities the trend is towards the replacement of electric motors and large-cylinder engines by multiple-cylinder gas engines. Experiments have been conducted and critical analyses made of flow conditions in wells equipped with various styles of tubing which give promise that tubing may be designed to fit individual well conditions. In those wells producing at less than maximum capacity, the gas-oil ratio has been shown to depend on the rate rather than on the method of production, or the design of equipment. Important factors in the design of screened pipe have been carefully analyzed and made the basis of a method for determining the required mesh. Remarkable progress has been made in the use of subsurface pressure data. In East Texas particularly, use of such data is providing a means for the control and equalization of water encroachment and is also pointing the way to a sound means of allocating to individual tracts an

Jan 1, 1933

By D. T. MacRoberts

A simple disturbance in a gas reservoir travels with a finite velocity which is nearly independent of the amplitude of the disturbance. As a result very complex transients may be set up which seriously affect observation at a well. The time of transient is much longer than commonly supposed. INTRODUCTION A change in pressure at a gas well is not propagated through the reservoir instantaneously but with a definite fin- ite velocity. Knowledge of the period ! of this transient is of value because: 1. Observations of pressure and flow-rate during the transient may affect interpretation of back-pressure tests. 2. Interference effects between wells may be used to determine continuity of formation. 3. Additional information concerning the physical characteris- tics may possibly be deduced from the behavior of a well during the transient. MATHEMATICAL DEVELOPMENT It will be assumed that the well is initially closed in and that the pressure is constant throlughout the reservoir. As the initial disturbance passes outward from the well it is further assumed that a logarithmic pressure distribution is established between the most distant point reached and the well, so that: <l> = ((/)r-<t>w) I ------------ + (/) . (1) Manuscript received at office of the Branch September 15. 1948. Paper presented at Branch Fall Meeting, Dallas. Texas. Oct. 4-6, 1948. r. = distance to any point between r and rw r = radius of drainge iw= radius of well (/) = potential (P for incompressible fluids, P2 for perfect gases) Up to the time the effect reaches the point r the production from the well will be: W= (Pr-P,,,) . (2) i b W = volume produced t = sand thickness F = fractional porosity Pr = reservoir pressure Pm = average pressure between r and rw Pb = atmospheric Pressure All pressures will subsequently be stated in atmospheres and the constant Pb will be omitted. This will be produced at a rate: dw t k (Pr³-PW2) do d 0 - . (3) log — Pw = pressure at the well k = permeability 0 = time = viscosity

Jan 1, 1949

By Advisory Editorial Board

FOR many years there has been no book that adequately represented the present state of the art of coal preparation-an art that has been rapidly changing during the passing years, and particularly during the last ten or fifteen years. In fact, changes of preparation have been so rapid that no book could keep abreast of their progress, and even the Proceedings of the technical societies have not been able to do so. It has been the intention of this committee and of the editor to make this book as nearly up to date as possible and to make it one that would appeal primarily to operating men, while at the same time adequately showing the theory back of the many processes used. The start of the war and the increased calls upon the time of the authors selected for the various chapters have slightly dimmed the brightness of the ideal intended, but the result undoubtedly brings the practice of preparation and its literature closer together than they ever have been before. It is the hope of the committee that this book will be useful both to those whose daily work is concerned with preparation and to consumers who use the product produced at the many fine and up-to-date coal plants throughout the country, which are now producing, as they always have done, all the coal needed by this country in its greatest crisis. While the committee has exercised a general supervision over the preparation of the various chapters, all of the correspondence and edi¬torial work have been done by Prof. David R. Mitchell, and it has been his untiring interest and devotion that have made the book possible-the credit is all his. Advisory Editorial Board, B. M. Bird Cadwallader Evans, Jr. Thomas Fraser W. H. Lesser William C. Mcciilloch J. B. Morrow H. S. Salmon Raymond E. Salvati Kenneth A. Spencer H. F. Yancey Howard N. Eavenson, Chairman.

Jan 1, 1943

By Sir John Cadnan

The production from the Maidan-i-Naftun area for the year ending March, 1928, was 5,340,000 tons (40,210,200 bbl.), an increase of nearly 13 per cent. over the production for the year ending in March, 1927. The production by years since the opening of the field in 1912 is given in the following table: [1 ton = 7.53 bbl.] Year Ended MaRch Tons Year Ended March Tons 1912 (7 months)............. 43,084 1920....................... 1,354,631 1913........................ 80,800 1921....................... 1,767,070 1914........................ 273,635 1922....................... 2,310,098 1915........................ 375,977 1923....................... 2,913,908 1916........................ 449,394 1924....................... 3,583,000 1917........................ 644,074 1925....................... 4,221,000 1918........................ 897,402 1926....................... 4,470,000 1919....................... 1,081,919 1927....................... 4,735,000 1928....................... 5,340,000 The actual production represents only a small proportion of the potential production. The Masjid-i-Suleiman Field The present producing unit, the Masjid-I-Suleiman, is an anticline some 20 miles in length by 4 miles in width, including three domes as so far proved. The producing horizon is a very open, dolomitic limestone, which, while showing much variation in texture and porosity, is so connected that the lowering of pressure in one section of the field quickly affects the whole area. The topography of the field is broken, with differences of well elevations of as much as 1100 ft. The depths to the limestone vary from about 800 to about 5000 ft. The closed-in pressure of the oil wells varies from zero to 50 lb. per sq. in. and that of the gas wells is about 450 Ib. Although the static oil level may be several hundred feet below ground level, in oil wells of high elevation, all the wells flow continuously or intermittently after they are once started—the majority continuously. The gas is very high in hydrogen sulfide in gas-oil wells of low pressure.

Jan 1, 1929

Maps and Mining Data for the Library. I suggest that the Institute Library can increase its usefulness by systematically soliciting from the engineers and mining companies all published reports and maps, and parts of reports and records, not of a private or confidential nature. If this is done an engineer assigned to report on a well-known property or district may depend on finding at the library a large amount of preliminary data and general information from these official and engineering reports relating to his prospective investigation. In many mining reports a large part of the report is of a general technical and scientific character, and there could be no good objection on the part of either the engineer, or his client to making such information thus of record. I believe there would be a great deal of information furnished by the engineers if they were properly solicited under this plan. I have found on different occasions that much work could be saved by such records now in the Library. The plan would also have the advantage of keeping the Library in closer touch with the active engineers, a feature to be desired. I also have in mind that the Library should undertake to collect all the prospectuses and financial literature which is issued in connection with mining. Of course a great deal of this is unreliable, but even this is valuable for record in the matter of legal and other investigations. I shall be glad to co-operate with you, and do anything I can to develop more in detail the general ideas above noted. Yours very truly, KIRBY THOMAS NOTE.-The Library of the Institute makes a specialty of collecting and filing material of this character, and the letter printed above is brought to the attention of members in the hope that they will co-operate by sending in copies of maps, reports of properties, etc.

Jan 11, 1913

By V. R. Garrias, R. V. Whetsel

The present study is intended as a preliminary statistical survey of the world&apos;s production of petroleum substitutes. The information presented is admittedly deficient. It is believed, however, that the increasing importance of these substitutes, particularly with Europe at war, justifies its presentation at this time, if for no other Table i.—Petroleum Subsiitues From Natural Gas Prom Coal Methane Liquid gas Liquid gas _ Manufactured gas Natural gasoline Gasoline Methyl alcohol Benzol Lubricants Etc. reason than to encourage enlightened pertinent discussion. The world&apos;s production in 1939 of petroleum substitutes—of which approxi-mately 97 per cent are direct substitutes for motor fuels—is tentatively estimated at 108,ooo,ooo bbl., or equivalent to the combined output of crude oil in 1939 of Rumania, Mexico and Colombia. With few exceptions, these figures of production represent also actual figures of consumption. The United States, owing mainly to its output of natural gasoline, leads all countries in the production of these products, with about 53 per cent of the total. In European countries, particularly Germany, the imminence of war in 1939 forced an increase in production and im- provement of methods of manufacturing motor fuels, largely from coal, with the result that this country produced in that year over 20,000,000 bbl. of substitutes. Since the beginning of hostilities, substitutes have offered more and more the means of meeting the unfavorable balance between supply and demand in European tes and Their Source Malerial From Oil From Molasses. Wood Shales Potatoes, Molasses.etc. From wood Shale oil Ethyl alcohol Producer gas Gasoline Methyl alcohol Gas oil Lubricants Etc. countries; the increase in production of these products being at least in part offset by the systematic bombing of synthetic plants and oil storage. The source materials and the resulting substitutes are listed in Table I. The following are the approximate gross heat equivalents of some substitutes to barrels of gasoline:

Jan 1, 1941

By Kendall E. Born

PRoduction of crude oil in Tennessee during 1938 was slightly more than 41,000 bbl., an increase of about 5000 bbl. over 1937. The production by counties and by fields is shown in Table 1. The increased production has resulted from continued activity in the Upper Cumberland district, especially in Clay County. The "Mississippi lime" production in Scott and Morgan Counties continued to show a further decline with a 1938 production of 12,379 bbl. as against 14,644 bbl. during 1937. Small scattered production from some half dozen wells in Clay, Pickett, and Fentress Counties, on which there are no accurate figures, is estimated at 500 bbl. during the year. The only natural gas marketed off the lease in Tennessee during 1938 was in Morgan County, where a small amount was furnished for the town of Sunbright and immediate vicinity. The gas occurs with the oil in the Boone Camp field and small amounts were put on the line from the near-by Coon Hollow and Seabolt pools. Developments There were 88 wells spudded in during 1938, of which 10 were drilling or only temporarily shut down on Dec. 31, 1938. Eighty wells were completed during the year; 16 produced oil and 3 were gas wells of undetermined quantity. The total footage drilled on 1938 completions was 63,385 ft. Flush production during the year totaled 850 bbl. per day. The more important wildcats are listed in Table 2; the distribution of oil and gas tests drilled during the year, according to physiographic divisions, is given in Table 3. Cumberland Plateau There were no completions in the producing pools in Scott and Morgan Counties. The decline in production in these areas has been steady for the past several years. In an effort to revive production, present plans include a repressuring program in the Boone Camp field in Morgan County early in 1939. There was one completion in Morgan

Jan 1, 1939

By B. M. Loring, I. R. Krame, F. M. Walters

NO observations on the mechanical properties of man-manganese alloys have been published since pure manganese became readily available, either distilled manganese or electrolytic manganese. The purpose of this investigation was to determine whether iron-manganese alloys are essentially brittle, as reported by Hadfield,&apos; or whether the lack of ductility observed was due to impurities in the alloys that he studied. Experimental Methods The alloys were melted in a roo-lb. high-frequency induction furnace with a magnesia crucible, using ingot iron and electrolytic manganese. The heats were split, the first giving six 18-lb, ingots and the second three. Each successive heat was higher in manganese and about 0.3 per cent silicon was added as ferrosilicon. The alloys forged without difficulty and were given a 9&apos; per Published by permission of the Navy Department. Manuscript received at the office of the Institute June 28. 1941. Issued as T.P. 1369 in Metals Technology. September 1941. * Division of Physical Metallfirgy Naval Roscarch Laboratory. Anacostia Station Washington. D. C. 1 References are at the end of the paper. 4 cent reduction to ¾-in. rounds. The chemical analysis of the alloys is given in Table I. The forged rods were homogenized for 224 hr. at r150°C. (2100°F.) and air-cooled. The alloys were tested in two conditions of heat-treatment: (I) as normalized from 870°C. (1600°F.) and (2) normalized from 870°C. and tempered for I hr. at 540°C. (Iooo°F.) and air-cooled. The tensils specimens were 0.505 in. in diameter with a 2-in. gauge length, and the impact specimens were v-notch Charpy. The proportional limit and yield strength were taken from the stress-strain diagrams drawn by a Peters recorder. The data obtained from the tensile test and the hardness measurements are given in Table 2. Specimens that were normalized are designated by N; those that were normalized and tempered by T. Alloy G was tempered after forging (D).

Jan 1, 1942

By J. J. Strohl, H. J. Schwellenbach

This paper relates the results obtained by decreasing the size of feed to a rod mill screen circuit. As would be expected, added production was gained and a finer grind with no tonnage loss was made possible. THE MacIntyre mill of the National Lead Co. has four parallel sections in which magnetic and gravity separations are made. Ore from a 5000-ton bin is fed by Hardinge constant weight feeders to a 6x12-ft open-end Marcy rod mill in each section. Rod mill discharge is bucket elevated to two 4x10-ft Tyrock screens whose oversize is returned to the rod mill. Screen undersize is pumped to Crockett separators for magnetite removal, and the Crockett tailings are sized and tabled to make an ilmenite concentrate. Minus 200-mesh material, overflowed by the Crockett and Dorrco sizers is thickened, de-slimed, and concentrated by flotation.&apos; By 1948, the development of a successful slime flotation process and numerous improvements in the gravity circuit of the mill had increased the capacity of the available concentrating equipment. At the same time, improvements in the operating techniques of the dry crushing plant and improved feeding of the crusher by the mining department had appreciably increased the production rate per operating hour in that plant. Therefore, it was decided to take advantage of the added crusher capacity to produce a finer rod mill feed and in that way increase grinding capacity. At approximately the same time, finer screens were installed in the rod mill circuits to give finer grind and thus improve liberation of the magnetite and ilmenite from the gangue and from one another. Prior to the first part of 1948, a 3/4-in. limiting screen was used for sizing rod mill feed. The first reduction in crushing plant screen size was to 1/2 in. With this screen, the circulating load in the tertiary crushing circuit was too high and plant capacity dropped below a practical hourly rate. A 9/16-in.-sq opening screen, installed next, proved satisfac-

Jan 1, 1951

By Clark Millison

The core recorder, a mechanical instr-ent for determining the exact depth at which core is recovered, drilled up or lost, is described. Examples of charts from the recorder are explained and interpreted. The uses of the core recorder are discussed. INTRODUCTION In the experience of geologists and engineers during coring operations on drilling wells, many will recall the times when a full core was not recovered and particularly when the requirement was urgent that they know exactly what part of the core was lost. To make this determination, the core recorder was designed. Its uses are many, and only the most obvious will be presented here. Although this discussion will be limited to drilling wells for petroleum, the core recorder can be used in any type of coring operation. The principle of the core recorder is the proportional reduction of the motion of core entering or dropping out of the core barrel to a stylus moving in such a manner as to record the reduced motion on a chart. The time element is registered on the same chart by the revolution of a clock which turns the chart drum. Thus the exact amount of core entering or dropping out of the core barrel is charted and the time of such entry or exit from the core barrel is precisely correlated to the depth at which the core is recovered or lost. Lack of movement of the stylus which is revealed by the continued revolution of the chart drum indicates that no core is entering the barrel. The principles are accomplished by an instrument placed inside of the core barrel. A cylinder which contains the clock and mechanical apparatus has a diameter smaller than that of the core barrel. Near the top of the cylinder is an eighteen hour clock which turns the drum that contains the chart. Near the bottom of the instrument is a serrated wheel which by friction against the inside of the core barrel is turned as core enters or drops out of the barrel.

Jan 1, 1949

By Francis Pyne

THE following notes are presented in an endeavour to point out the disadvantages attending the use of chrome brick in reverberatory furnaces used in the treatment of materials that are too valuable to allow any great amount of metal absorption by the brick. Several years ago one of the large Eastern copper refineries decided to utilize basic material in place of siliceous material in the walls of their reverberatory furnaces for the treatment of very foul blister copper, as the latter rapidly corroded the siliceous linings. It was also expected that there would be less slag formation, with a consequent decrease in the cost of treatment and a reduction in the metal losses. Magnesite brick were first used, but while the corrosive action of the foul material was greatly reduced, and the amount of. slag formed was very much less, the magnesite proved to be unsatisfactory in certain parts of the furnace, because of its tendency to crack and span badly when subjected to the alternate heating and cooling that takes place in a reverberatory refining furnace. This made many repairs necessary, and consequent frequent interruption in the operation of the furnace, which, together with the high price of the magnesite brick, ran up the cost of maintenance to an unreasonable amount. It was, therefore, decided to substitute chronic brick for magnesite brick in the parts of the furnace affected. The results, as far as the reverberatory furnace was concerned, were very satisfactory. The corrosion due to the action of the foul blister was small and the amount of slag formed was no greater than when using magnesite, and the tendency to crack and spill shown by the magnesite was eliminated. Gradually the use of chrome brick was extended to all furnaces; those treating blister copper as well as those melting cathodes, and the results were so satin-, factory that the siliceous roofs were replaced by roofs of chrome brick except in certain places where experience showed a more satisfactory performance on the part of the silica brick.

Jan 12, 1917

By Randolph H. Schnitzel

MARINGER and schwopel have investigated the internal friction of high-purity molybdenum. After light tensile deformation, they observed internal-friction peaks at about 230° to 290°C, 310" to 370°C, and 820° to 870°C, which they have attributed to the interstitials carbon and nitrogen, and to stress relaxation across grain boundaries, respectively. The electron-beam melting technique has been successfully applied to refractory metals including molybdenum. By this technique single crystals and higher-purity levels than those of commercial molybdenum are readily obtained. Since electron-beam processed molybdenum possesses such desirable qualities, it seems reasonable to determine: u) if internal-friction peaks do exist in these single crystals, and b) if so, whether or not these peaks can possibly be attributed to the motion of specific interstitials. The molybdenum crystal used in this investigation received four melting passes in the electron-beam furnace. This crystal was about 11 in. long and had an orientation 4 deg from the [loo]. The process of making wire consisted of grinding the crystal rod to a diameter of 0.040 in. and then electropolishing to a final diameter of 0.030 in. Since Maringer and schwopel have indicated that the peak at 230" to 290°C may be due to the presence of carbon, the wire was cut into two equal lengths and one length was carburized prior to the internal-friction measurements. The critical condition necessary for the controlled addition of carbon proved to be a difficult problem. Therefore, a simpler nonequilibrium method was used. This consisted of carburizing at 2000°C in graphite powder to obtain a case, annealing at higher temperatures in vacuum to partially dissolve carbon into the molybdenum, and then removing the remaining case by dissolving it elec-trolytically. After this treatment, metallographic examination of a small section of the specimen revealed carbides in the matrix. Vacuum fusion and carbon analyses for both the virgin (as melted) and carburized specimens are given in Table I. Internal-friction measurements of these specimens were conducted in an apparatus of conventional

Jan 1, 1964

By A. C. Dorenfeld

Ores of the Mammoth mining district, some 45 miles northeast of Tucson, Arizona, are treated by Mammoth-St. Anthony, Ltd. The ores now treated come from a complex system of veins and faults, comprising three mines, in close proximity: The Mohawk, Mammoth and Collins. The ore treated in the past was oxide ore, which contains economic amounts of gold, silver, lead, molybdenum, and vanadium (as wulfenite and vanadanite). The lead-zinc sulphide ore has never been treated before. The Ore The sulphide ore contains galena, sphalerite, marmatite, pyrite and some chal-copyrite, covellite, chalcocite and bornite, as well as small amounts of gold and silver. The value of the ore is principally in the lead and zinc content. The lead-zinc sulphides are substantially liberated at a minus 65-mesh grind. However, a large part of the chalcopyrite and other copper minerals is not freed, but remains as pin points on the sphalerite. Economically, the copper is unimportant. The gangue is a rhyolite granite, with very little limestone. There is no molybdenum or vanadikm in the sulphide ore. History of Sulphide Treatment Test work on samples of the sulphide ore was conducted by several equipment companies, the Arizona Bureau of Mines and the company&apos;s laboratory. Results of this test work indicated that for some reason, which at the time could not be explained, recoveries would be only about 65 per cent lead and 50 per cent zinc. Notwithstanding this, because of the nation&apos;s need for metals, the management built a 150-ton treatment plant. The mill was started in June 1942. During December 1942, using the standard method of treating lead-zinc ore, the monthly results were as shown in Table I. These results were poor. Too much lead was in the zinc concentrate, and too much zinc in the lead concentrate. It should be noted here. that prior to December attempts were made to depress the sphalerite with large and varied amounts of cyanide, zinc sulphate, and sodium sulphite with poor results.

Jan 1, 1947

By H. J. Schwellenbach, J. J. Strohl

This paper relates the results obtained by decreasing the size of feed to a rod mill screen circuit. As would be expected, added production was gained and a finer grind with no tonnage loss was made possible. THE MacIntyre mill of the National Lead Co. has four parallel sections in which magnetic and gravity separations are made. Ore from a 5000-ton bin is fed by Hardinge constant weight feeders to a 6x12-ft open-end Marcy rod mill in each section. Rod mill discharge is bucket elevated to two 4x10-ft Tyrock screens whose oversize is returned to the rod mill. Screen undersize is pumped to Crockett separators for magnetite removal, and the Crockett tailings are sized and tabled to make an ilmenite concentrate. Minus 200-mesh material, overflowed by the Crockett and Dorrco sizers is thickened, de-slimed, and concentrated by flotation.&apos; By 1948, the development of a successful slime flotation process and numerous improvements in the gravity circuit of the mill had increased the capacity of the available concentrating equipment. At the same time, improvements in the operating techniques of the dry crushing plant and improved feeding of the crusher by the mining department had appreciably increased the production rate per operating hour in that plant. Therefore, it was decided to take advantage of the added crusher capacity to produce a finer rod mill feed and in that way increase grinding capacity. At approximately the same time, finer screens were installed in the rod mill circuits to give finer grind and thus improve liberation of the magnetite and ilmenite from the gangue and from one another. Prior to the first part of 1948, a 3/4-in. limiting screen was used for sizing rod mill feed. The first reduction in crushing plant screen size was to 1/2 in. With this screen, the circulating load in the tertiary crushing circuit was too high and plant capacity dropped below a practical hourly rate. A 9/16-in.-sq opening screen, installed next, proved satisfac-

Jan 1, 1951

By Clark Millison

The core recorder, a mechanical instr-ent for determining the exact depth at which core is recovered, drilled up or lost, is described. Examples of charts from the recorder are explained and interpreted. The uses of the core recorder are discussed. INTRODUCTION In the experience of geologists and engineers during coring operations on drilling wells, many will recall the times when a full core was not recovered and particularly when the requirement was urgent that they know exactly what part of the core was lost. To make this determination, the core recorder was designed. Its uses are many, and only the most obvious will be presented here. Although this discussion will be limited to drilling wells for petroleum, the core recorder can be used in any type of coring operation. The principle of the core recorder is the proportional reduction of the motion of core entering or dropping out of the core barrel to a stylus moving in such a manner as to record the reduced motion on a chart. The time element is registered on the same chart by the revolution of a clock which turns the chart drum. Thus the exact amount of core entering or dropping out of the core barrel is charted and the time of such entry or exit from the core barrel is precisely correlated to the depth at which the core is recovered or lost. Lack of movement of the stylus which is revealed by the continued revolution of the chart drum indicates that no core is entering the barrel. The principles are accomplished by an instrument placed inside of the core barrel. A cylinder which contains the clock and mechanical apparatus has a diameter smaller than that of the core barrel. Near the top of the cylinder is an eighteen hour clock which turns the drum that contains the chart. Near the bottom of the instrument is a serrated wheel which by friction against the inside of the core barrel is turned as core enters or drops out of the barrel.

Jan 1, 1949