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The pressure of the gas in equilibrium with sphalerite has been determined in the temperature range of 680' to 825°C, using the Knudsen orifice method. A comparison of these experimental pressures with those calculated from thermal data and from other equilibrium measurements shows that the vapor above sphalerite is predominantly dissociated ZnS. Equations have been given for correctly calculating dissociation pressures using the Knudsen orifice method. It has been shown that the experimentally determined pressure is the same, whether the zinc sulphide is sphalerite or not, or a mixture of wurtzite and sphalerite. CONFLICTING points of view appear in the literature on the constitution of the vapor in equilibrium with solid zinc sulphide in the vicinity of 800°C. By comparing the dissociation pressure calculated from thermodynamic data and the vapor-pressure determination of ZnS by Veselovski,1 Lumsden2 has concluded that the vapor consists largely of dissociated ZnS. Sen Gupta,' however, concludes from his spectroscopic determinations that the vapor is largely ZnS molecules. In view of the fact that the thermodynamically calculated' dissociation pressure is higher than that experimentally measured by Veselovski, it seemed in order to repeat Veselovski's measurements. Experimental Procedure The method used for the determination of the pressures in this papel- is the Knudsen effusion cell. The apparatus and procedure were described in a previous paper- from this laboratory on the determination of the vapor pressure of silver. The only difference is that the Knudsen cell in this work is made from platinum and there is no external cover around the cell. The cell is an ordinary platinum crucible of 2.2 cm top diameter with a capsule cover. It was thought that platinum might stand up at these temperatures to the solid and gaseous ZnS, since it was found that the weight of the platinum cell itself did not change appreciably on heating ZnS in it at the working temperatures. To insure that reaction of the zinc sulphide with the cell was not giving' a false value, a stabilized zirconia cell was employed for check runs. Fig. 1 shows the comparison, which is satisfactory. Veselovski previously had measured the vapor pressure of ZnS using a silica Knudsen effusion cell. On repeating his experiment in this laboratory, it was found that ZnS at-tacked the silica cell, giving it a marked frosty appearance. This led to the belief that Veselovski's result:; may be in error. Also, he was operating at pressures above the range ordinarily considered safe for the Knudsen method. The effusion rate was measured by weighing the cell before and after each run. The weight loss during heating to temperature and cooling down was measured and subtracted from the weight loss during the actual run. The zinc sulphide used in this investigation was from two sources: Fisher cp grade, and a sample of pure sphalerite supplied by Mr. E. A. Anderson of the New Jersey Zinc Co. Before and after the series of runs with Fisher ZnS, X-ray analysis showed that both wurtzite and sphalerite were present. However, the ratio of sphalerite to wurtzite increased. All measurements were made below the transition temperature which has been reported" to be 1020°C. The data obtained in this investigation are tabulated in Table I. The pressure was calculated by the usual Knudsen formula" on the assumption that ZnS molecules were effusing. From these data, using pure sphalerite in the platinum Knudsen cell, the vapor pressure of ZnS, in mm of Hg, as a function of temperature is given by the solid line in Fig. 1. The best straight line, as determined by the method of least squares, is given by 14405 logpzns =-14405/T +11.032. A comparison of these results with Veselovski's shows that his results are about 50 pct lower. Discussion The vapor in equilibrium with solid zinc sulphide in the temperature range of this study will consist of Zn, S2, and ZnS mol, since other species of zinc and sulphur' are relatively unstable. The question to be settled is whether or not ZnS is largely dissociated. The derivation8 which follows gives the method of calculating the pressure of zinc and sulphur over solid ZnS, assuming complete dissociation, from Knudsen cell data. The free energy of the reaction 2 ZnS(solid) ? 2 Zn(gas) + S2(gas) is given by ?F?° = -RT In K = —RT In p12p2 where p1 is the zinc pressure and p is the sulphur pressure. If dissociation occurs in a closed system,

Jan 1, 1955

Melbourne, capital of sedate Victoria, is oddly enough the home of a game known as "Australian Rules." Euphemistically described by devotees of the game as a cross between Rugby and Soccer, it appears to the novice to be more akin to organized mayhem. They don't even play it in some parts of Australia, but in Melbourne 60,000 to 80,000 whooping spectators throng the Cricket club of a Saturday afternoon to see a match. Actually, the game is fast and grueling but the victory laurels always go to the skillful team, the one that plays the ball rather than the man. Australians also play the ball in their ground rules affecting those interested in mineral exploration and mining. Prospecting Rights: Throughout the island continent, nearly all mineral rights are reserved to the Crown, administered by the individual states and, in the case of the territories by the Commonwealth government. The owner of the surface rights cannot sit on his minerals, and the term minerals even includes sand and gravel. Prospectors are protected by mining codes or ordinances of the various governments, which are quite similar from state to state.

Jan 10, 1964

By James N. Gundersen

Geological Engineering can be all-encompassing and it necessarily overlaps many applications of economic and applied geology. Other review articles will cover specific developments in rock mechanics, open-pit and underground mining, geology, geochemistry, geophysics and geohydrology- all of which overlap many fields of economic and applied geology. Nevertheless, there still remains a diversity of new and innovative applications of geology to engineering works through the activities of federal and state agencies, college and university departments, and industrial or consultant firms-particularly with respect to the properties of earth materials and their behavior "as-is" in nature or under the stress of engineering works. Governmental Agencies: Federal John T. McGill (Chief: Engineering Geology Branch; USGS, Denver) relates that recently the Engineering Geology Branch, together with several other branches of the Office of Environmental Geology, has undertaken the production of interpretive maps of unusual character. These maps are commonly called special-purpose or single concept maps. A folio, or series of maps, is prepared for each topographic quadrangle or area selected for study. The individual maps in a given series are printed on standard-size sheets so that they can be bound together if desired.

Jan 3, 1974

Many of those who attended the meeting at Chicago spent the first part of the following week in Pittsburgh, when the Experiment Station of the Bureau of Mines was dedicated and the fourth annual First Aid and Mine Rescue Contests were, held. The Bureau buildings were open for inspection during the three days, Monday, Tuesday, and Wednesday. The dedicatory ceremonies were held in the Bureau of Mines main building, Monday morning, Sept. 29, Mr. T. J. Gillespie, representing the Pittsburgh Chamber of Commerce, presiding. In his address of welcome, Hon. E. V. Babcock, Mayor of Pittsburgh, said: "The reclamation work already done stands out conspicuously beneficial to industry and populace alike all over the United States. It has demonstrated methods of preservation of life and reclaiming of injured persons which are new and greatly beneficial to modern civiliza-tion. The establishment of this institution in Pittsburgh was greatly desired, and now it is here it is greatly appreciated." The response was given by First-Assistant Secretary of the Interior Vogelsang, who represented Secretary Franklin K. Lane. He said that the Bureau of Mines did more during the war for the triumph of American arms than any other institution.

Jan 11, 1919

By Louis A. Panek

Ground movements in the zone adjoining an active cave were measured at four sites in the San Manuel Mine. Measurements were made to detect extension and inclination, basic components of displacement, which can readily be duplicated by mine personnel using relatively simple equipment. The displacements demonstrated the development of a zone of strain relief surrounding the active cave, within which the ground tends to migrate toward the cave, and extension cracks develop tangential to the cave. This expansion of the ground surrounding an active cave can be exploited to promote future caving; it also creates special problems with respect to the design of an effective ground support system for mine openings in the production area.

Jan 1, 1981

The following is an incomplete list of members and guests who called at Institute headquarters during the period July 11, 1918 to August 11, 1918. John Carter Anderson, Tucson, Ariz. Edson S. Pettis, San Francisco, Cal. Lieut. Frank A. Ayer, Tyrone, N. M. Wm. H. Rettie, Yonkers, N. Y. W. R. Canton, McGill, Nev. J. T. Robertson, Port Richmond, S. I. Alden Crankshaw, Palmerton, Pa. Harry O. Robinson, Margarita, John Davenport, W. Norfolk, Va. Venezuela. A. Faison Dickson. C. K. Seng, Gilbert, Minn. F. A. Fahrenwald, Cleveland, C). E. S. Sheffield. L. Hall Goodwin, New York. H. G. Smith. W. H. W. Hamilton, Baker, Ore. Harry M. Spoor. Floyd D. James, St. Louis, Mo. H. H. Stoek, Urbana, Ill. George A. Laird. Arthur L. Tuttle, Copperhill, Tenn. J. W. McBride, Spokane, Wash. Thor Warner, Phoenix, Ariz. Arthur Notman, Bisbee, Ariz. Christopher G. Atwater, Manager Agricultural Dept., The Barrett Co., is in Washington serving the U. S. Navy Bureau of ordnance in connection with the Navy nitrate plant recently authorized by Congress. Edward Ludlam Blossom announces his marriage to Mabel Townsend, daughter of Mr. and Mrs. George Comings Mills, on Wednesday, July 17, 1918, at New York City.

Jan 9, 1918

By R. J. Greaves

High-resolution seismic reflection profiling can be used to evaluate detailed structural and stratigraphic features of coal prospects. Since most coal prospects are relatively shallow, less than 1000 m (3000 ft) deep, high sampling rates in space and time can be used effectively to improve vertical and lateral resolution of seismic data. The case study presented here shows how seismic data was used to evaluate the Wyodak coal at a prospective coal gasification site. The data were used to map the detailed structure and thickness of the coal and to search for lateral discontinuities, such as pinchouts and faults. An important find was a paleochannel cutting across the base of the coal seam, which was later confirmed by drilling.

Jan 1, 1986

By A. W. Ashbrook

There are essentially three main classifications for extractants: acidic, basic, and neutral. The acidic and basic are also referred to as cationic and anionic, respectively. Some extractants are shown in Table 11-1. Acidic Extractants Acidic extractants which are of use, because of cost and/or insolubility in water, are alkylphosphoric, sulphonic, aliphatic monocarboxylic acids and naphthalene derivatives.

Jan 1, 1978

The regular activities of the Institute are financed mainly by income derived from members' dues, from advertising in MINING AND METALLURGY, and from the sale of publications to the public. In addition, collateral activities and special projects are financed each year by means of income from endowed funds controlled and administered by the Institute. In the aggregate, the principal sums of these endowments amount to more than $530,000. An active effort is being made to in¬crease the endowment funds of the Institute through a standing committee, of which H. T. Hamilton is chairman, and of which the other members are: W. H. Aldridge, George D. Barron, Cleveland E. Dodge, D. C. Jackling, Henry Krumb and J. V. W. Reynders. This committee feels that there exists a tremendous opportunity for the Institute to be of ever-growing service to the public, to the mineral industries, and to the profession. It welcomes suggestions as to names of men of means who are vitally interested in the mineral industries, and to whom the opportunity to make a contribution or bequest might appeal favorably if presented in the proper light by the committee.

Jan 1, 1944

By AIME AIME

INSTITUTE HEADQUARTERS, Hotel Statler. On Monday evening, Oct. 28, 1912, the visiting members and guests were informally received by the Local Committee at the Headquarters of the Institute at. the Hotel Statler. The evening was very pleasantly spent in renewing old acquaintances and friendships and in forming new ones. The first session, held Tuesday morning, Oct. 29, 1912, in the impressive Assembly-Room of the hotel, was called to order by David T. Croxton, Chairman of the Local Committee. Mr. Croxton introduced the Hon. Newton D. Baker, Mayor of Cleveland, who extended a cordial welcome to the members and guests present. James F. Kemp, President of the Institute, who subsequently presided at the meeting, responded in behalf of the Institute.

Nov 1, 1912

A. B. Cummins (Industrial Minerals Review, P. 164) was born in Los Angeles, Calif. and attended the University of Chicago and University of California. He received a B.S. and Ph.D. degree. He has worked at University of California and as a development and research engineer with Celite Co. He is at the present manager of research at Johns-Manville Co. in Manville, N. J. Dr. Cummins is an AIME member and has presented previous papers before it. He resides in Bound Brook, N. J. Aureal T. Cross (Recent Coal Geology Research, P. 202) was born in Findlay, Ohio. He attended Coe College in Cedar Rapids, Iowa and the University of Cincinnati. He received major honors at Coe College and was given a National Research Council Fellowship in geology from 1943 to 1944. He was assistant professor at Notre Dame University from 1943 to 1946. Mr. Cross was a paleobotanist with U. S. Bureau of Mines, Central Experiment Station, Pittsburgh. He was assistant professor of geology at West Virginia University from 1949 to date. He holds membership in Geological Society of America, Paleontological Society, Botanical Society, Sigma Xi, and numerous similar societies.

Jan 1, 1952

The regular activities of the Insti¬tute are financed mainly by income derived from members' dues, from advertising in MINING AND METALLURGY, and from the sale of publications to the public. In addition, collateral activities and special projects are financed each year by means of income from endowed funds controlled and administered by the Institute. In the aggregate, the principal sums of these endowments amount to more than $530,000. An active effort is being made to in¬crease the endowment funds of the Institute through a standing committee, of which H. T. Hamilton is chairman, and of which the other members are: W. H. Aldridge, George D. Barron, Cleveland E. Dodge, D. C. Jackling, Henry Krumb and J. V. W. Reynders. This committee feels that there exists a tremendous opportunity for the Institute to be of ever-growing service to the public, to the mineral industries, and to the profession. It welcomes suggestions as to names of men of means who are vitally interested in the mineral industries, and to whom the opportunity to make a contribution or bequest might appeal favorably if presented in the proper light by the committee.

Jan 1, 1942

By Oliver Bowles

ALTHOUGH Oliver Bowles retired as chief of the nonmetal economics division of the Bureau of Mines last year, that retirement has not lessened his active interest in the field of nonmetallic minerals, in writing, nor in his hobby, cultivation of African violets. Excellent co-ordination of the timing of a professional meeting and a flower show permitted him on at least one occasion to attend technical sessions and take in the African violet exhibition which happily arrived simultaneously in one city. Dr. Bowles celebrated his seventieth birthday on Jan. 10, 1947, and

Jan 1, 1948

By AIME AIME

THE papers presented at the geophysics session" on Feb. 17 were concerned largely with three aspects of the science. The first ones dealt with the transmission of elastic waves through the earth, then electrical methods came in for their share of attention and finally, the question of the teaching of geo- physics came up for the first time at these meetings. Also, for the first time, there was a symposium of mining men on the practical value of the new science. The paper (T. P. 267) entitled "Seismic Propagation Paths" was presented by Donald C. Barton in the absence of the authors. It dealt with an investigation of the speed of propagation of seismic waves. The latter travel in a straight line when proceeding at a constant velocity, but if the velocity increases at increasing depths, the line of travel becomes a curve. Under the assumption of the authors this curve is found to be the arc of a circle, and their paper gives calculations for reflected and refracted wave paths under these circumstances.

Jan 1, 1930

By John C. Branner

Inquiries are frequently made concerning the chalk- and clay-beds of Arkansas, usually with a view to the manufacture of Portland cement. The chalk-deposits were first described by Professor R. T. Hill in the annual report of the Geological Survey of Arkansas for 1888, vol. ii., pp. 153-162. Since the publication of that report I have visited localities then unknown, and have accumulated considerable additional information concerning these deposits, dl of which is brought together in the present paper. My report upon the clays of the State has never been published; only a few of the more conveniently available deposits are mentioned in the present paper. The Chalk-Deposits. Stratigraphic Position of the Chalk.—The chalk-deposits of Arkansas belong to rocks of Cretaceous age. The Cretaceous rocks are confined to a single definite area in Southwest Arkansas. Beginning on the Ouachita river, a little northeast of Arkadelphia, its southern or upper margin follows a line about five miles southeast of, and approximately parallel to, the St. Louis, Iron Mountain and Southern Railway from Arkadelphia

Jan 1, 1898

Executive SIDNEY .J. JENNINGS, Chairman GEORGE D. BAR HON .I. E. JOHNSON, JR. EDWIN LUDLOW ROBERT M. RAYMOND Membership KARL EILERS, chairman LEWIS W. FRANCIS .1. E. JOHNSON, JR. LOUIS D. HUNTOON ARTHUR. L. WALKER Finance GEORGE D. BARRON. Chairman. CHARLES F. RAND BENJAMIN B. THAYER Library E. GYBBON SPILSBURY1 Chairman ALEX C. HUMIPHREYS3 GEORGE C. STONE .J. H. JANEWAY4 BRADLEY STOUGHTON Papers and Publications BRADLEY STOUGHTON, Chairman

Jan 10, 1918

By AIME AIME

THE luncheon of the Milling Methods Committee in the Engineers' Club, on Feb. 16, was distinctly a social affair, although several matters of a non-milling nature were fruitfully discussed. The session* on Milling Methods, the same afternoon, attracted a gathering which overtaxed the capacity of the Board Room on the fifteenth floor. Galen H. Clevenger presided, with the moral reinforcement of Charles Butters. As all papers were available in printed form, and since synopses have appeared in MINING & METALLURGY, it is unnecessary to cover the contents of each in detail here. The first paper (T. P. 410), by Leaver and Woolf, on the "Flotation of Minor Gold in Large-scale Copper "Concentrators," was excellently summarized by R. S. Dean of the U. S. Bureau of Mines, who stressed the -very definite action of lime as a depressant of gold, and showed how the authors had worked out the best conditions of alkalinity, pH concentration and reagents for -optimum recovery of gold along with base metals, especially where lime had to be used to depress pyrite. No discussion was evoked.

Jan 1, 1931

By Jack L. Taylor

Single crystals of tungsten grown from powder -metallurgy swaged rod by high-temperative annealing were deformed in tetzsion at temperatures from 2500 to 5000 OF. Orientation of specittzen tensile axis, strained ratrix, and defortnation bands was determined optically by reflections from {110} etch pits. Slip traces meve analyzed and slip directiorz determined. Results indicate that {110}(111) , {112){111}. and {123}{111} type slip occur in tungsten over the terpe,atuve rutge investigated. Slip is orientation-dependent occuvring on tCuzt cowzbitzation oj slip plane and direction which has the highest critical resolved shear stvess. Overshooting appears to be a general occurrence between 2500' and 5000°F. Dejornatiotz bands show rotation in a directiorz opposite to the yotation of tire tensile axis. DEFORMATION in bcc metals has been reviewed by Maddin and Chen,' Keh and eissman,' and most recently by Nabarro, Basinski, and olt. From these reviews it is apparent that some disagreement exists concerning the crystallography of plastic deformation in bcc metals. There is evidence of noncrystallo-graphic slip, the crystal slipping on or near a noncrys-tallographic plane in the (111) zone for which the resolved shear stress is greatest. There is also evidence to indicate that crystallographic slip occurs in the planes of the same zone. On the other hand, there is agreement that the close-packed direction ( 111) is the slip direction in bcc metals. Further, in pure bcc metals4 and alloys the operative crystallographic slip systems are strongly dependent on temperature. Both crystallographic and noncrystallographic slip have been reportede8 in tungsten, a group VIA bcc metal. The number of slip families which operate in the case of crystallographic slip, however, has been in question. The earliest study by oucher' of single-crystal tungsten tested at temperatures of 1800 to 5000°F led to the conclusion that only {112)( 111) type slip operated. Raymond and eumann recently reached the same conclusion studying deformation by rolling of plasma-flame single crystals at 1800°F; however, only [loo] and [110] orientations were studied. Work at high temperatures by Leber and Pughs on tungsten and Chen and Maddin9 on molybdenum suggests that conjugate slip on nonparallel (110) planes may account for the slip on (112) and (123) planes found by others working with bcc metals. The present paper presents evidence of three families or modes of slip in tungsten in the temperature EXPERIMENTAL PROCEDURE Material. Standard microtensile specimens, 0.160 in. diam by 0.640 in. gage length, were ground from commercial powder-metallurgy swaged tungsten rod, type MK. Specimens were heated for 10 min at 5150°F or 6 hr at 5400°F in vacuum of 1 x 105 Torr or less to produce single crystals. At the lower temperature an average of two out of seven specimens heated in a group developed single crystals throughout the specimen length as shown in Fig. 1, the rest remaining wholly poly crystalline. At the higher temperature, three or four out of seven specimens became single crystal. Other than to note that Laue X-ray photographs generally showed sharp, well-defined spots, no attempt was made to assess crystal perfection or measure dislocation density. Two tungsten single crystals grown from the melt by the plasma-arc process were also used for this study.

Jan 1, 1967

By C. A. Meissner

The; following is a further discussion of the paper of James Qayley, " The Application of Dry-Air Blast to the Manufacture of Iron " (Trans., xxxv., 746), with special reference to his supplementary paper (Bi-Monthly Bulletin, No. 4, July, 1905, pp. 797 to 819), and to the paper of J. E. Johnson, Jr., " Notes on the Physical Action of the Blast Furnace " (Bi-Monthly Bulletin, No. 5, September, 1905, pp. 1111 to 1146). Mr. Gayley's paper has been discussed also by E. Windsor Richards, R. w. Raymond, E. H. Saniter, W. J. Poster, H. M. Howe, V, Pendred, B. H. Thwaite, James Gayley and Alexander Pourcel (Trans., xxxv., pp. 1022 to 1042), Joseph W. Richards (Bi-Monthly Bulletin, No. 4, July, 1905, pp. '703 to 718); T. W. Robinson (Bi-Monthly Bulletin, No. 4, July, 1905, pp. 788 to 796); C. B. Dudley, R. W. Raymond, J. E. Johnson, Jr., W. F. Mattes, James Gayley, David Baker, John Birkin-bine and F. E. Bachman (Bi-Monthly Bulletin, No. 5, Septem-

Jan 1, 1907

By S. F. Turcotte, B. J. Grierson

At the Q. I. T. ilmenite smelter, nine electric furnaces produce titania slag and iron At high power levels, a furnace requires either a slag or an iron tap approximately once an hour, using rail cars as slag receptacles and ladles for iron. The correct scheduling of taps is an important operational tool due to peak power load and operational considerations. Over recent years, large increases in furnace capacity have imposed severe strains on the product handling facilities. This situation results in loss of production when several taps are bunched, because of an in- ability to handle many taps simultaneously. An on-line computer program has been developed to generate schedules for tapping a single furnace. By improved scheduling, this program can en- large the tonnage of each tap and minimize the number of taps, while reducing traffic congestion and unit cost s. Future plans call for extension of this technique to all nine furnaces with addition of a master scheduling program to optimize the overall traffic flow in the smelter aisle.

Jan 1, 1969