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INDUSTRIAL MINERALS DIVISION (Nonmetallics) Established as a Division March 15, 1935 Ian Campbell, Chairman Robert C Stephenson, Eastern Vice-Chairman Allen Cole, Southeastern Vice-Chairman David P Hale, Jr, Rocky Mountain Vice-Chairman G H Waterman, Western Vice-Chairman M F Goudge, Canadian Vice-Chairman James Norton, Secretary-Treasurer Mineral Deposits Branch U S Geological Survey Washington 25, D C.

Jan 1, 1952

PRESIDENT OF THE COUNCIL ROBERT W. HUNT CHICAGO, ILL. (Term expires February, 1907 ) VICE-PRESIDENTS OF THE COUNCIL WILLIAM P. BLAKE TUCSON, ARIL. THOMAS F COLE DULUTH, MINN. IRVING A. STEARNS WLKES-BARRE, PA. (Term expires February, 1907 ) HENRY M HOWE NEW YORK, N. Y. J. B GRANT DENVER, COLO. JAMES D HAGUE NEW YORK, N. Y. (Term expires February, 1909 )

Jan 1, 1910

By Donald B. Gillies

THE great source of iron ore for the furnaces of this country has been the Lake Superior district. Ore was first discovered there in 1844, and the first shipments made via the Great Lakes in 1852 to a furnace at New Castle, Pa. The stream of ore from that region increased slowly to exceed a million tons in 1873, and did not reach 10 million tons until 1895. By 1901 it exceeded 20 million tons, and in 1907 over 40 million tons. Total Lake Superior output through 1948 was about 2500 million long tons. Outside the Lake Superior district are the Southern district, including mainly Alabama, Georgia, Missouri, and Texas; the Eastern district of New York, New Jersey, and Pennsylvania; the Western district embracing Wyoming, Utah, and California.

Jan 1, 1949

Elected Died 1895 *ABBOTT, AI ATTHUR 1908 1882 *ABBOTT, ARTHUR V 1906 1905 * ABE, MASAYOSHI 1909 1903 * ADAMS, CHARLES C. 1905 1906 * ADAMS, JOHN C. 1913 1905 * ADAMS, WILLAMS 1909 1903 * ADAMS, W. EDWARDS 1910 1884 *ADDY, MATTHEW 1896 1906 * AFFLECK, WILLIAM A. 1911 1889 * AKERS, WILLIAMS A. 1906 1905 * ALABASTER, RUPPERT C. 1911 1899 * ALBERGER, LOUIS R. 1911 1894 *ALLEN R B 1896 1905 * ALLEN, R. SCOTT 1906 1874 * AMIOT, H. 1892 1886 *AMSLER, CARL 1894 1898 ** ANDRSON, JOHN W 1905 1895 *ÅNGSTROM, CARL 1901 1887 * ARCHBALD, JAMES 1910 1900 * ARLETT, GEORGE H 1906 1895 *ARMSTRONG, JOHN F 1898 1882 *ARNOLDS, HUGO 1886 1875 *ASHBURNER, CHARLES A 1889 1872 *ASIIBURNER, WILLIAM 1887 1883 *ATKINS, C M , JR 1885

Jan 1, 1917

By Richmond Bennett

Airborne geochemistry became a reality with the advent of a high-sensitivity air¬borne gamma ray spectrometer with large volume NAI(Tl) crystal detectors. The high-sensitivity spectrometer measures small variations in the concentration of potassium (as Ks°), thorium (as Tl308) and uranium (as Bi.214) along the flight lines in the area surveyed. Hydrothermal dispersion patterns are indicated by anomalous measured values of the concentrations of potassium, thorium, uranium, or their ratios. In two recent Australian survey areas, copper mineralization was located along favorable structures within hydrothermal dispersion patterns delineated by airborne geochemical surveys. In metamorphic terrane where there had been po¬tassium metasomatism, the hydrothermal dispersion patterns were indicated by high potassium/uranium ratios (K40/Bi). In a sedimentary environment that had been intruded by a stock, the path of hydrothermal fluids was indicated by uranium (Bi214), thorium (TV'), and uranium/ thorium (Bi214/Tl208) ratios.

Jan 1, 1972

By D. Turnbull, A. M. Turkalo

It is well known that if copper that has been severely cold-worked by rolling (70-98 pct) is heated to high temperatures a small number of large grains are formed at the expense of the fine grained structure that appears upon primary recrystallization. Dahl and Pawlek,' Cook and Mac-Quarie,2 Ward,3 and Boas and Bowles4 have studied this phenomenon in copper. It has been reported as taking place with measurable velocities in the temperature range 700-1080". Boas and Bowles have reported that the time necessary for the transformation is of the order of days at 700°C. According to Ward3 the number of secondary grains which appear in OFHC copper decrease with increasing perfection of cubical alignment after primary recrystallization; also the perfection of cubical alignment increases with decreasing grain size prior to the final reduction. In this investigation two heats, A and B, of especially high purity copper (99.999 pct) supplied by the American Smelting and Refining Co., were used. The behavior of samples prepared from the two heats was qualitatively very similar providing that the grain sizes established prior to the final reduction were about the same. We observed that in specimens prepared from bars which were relatively coarse grained prior to final reduction secondary recrystallization took place at a rapid rate at temperatures as low as 500°C. This is about 200-300°C lower than the temperature necessary to obtain fairly rapid transformation in OFHC copper. A 0.22 in. thick rectangular bar of lot B was cold-reduced 60 pct by straight rolling and given a penultimate annealing treatment at 250°C. Following this it was cold-reduced 90 pct and heated to various temperatures in the range 450-1040°C. The specimens were about 8 mils thick

Jan 1, 1950

By P. D. Wilson

The genesis of some orebodies has been explained by the mingling and chemical interaction of water solutions of different compositions and the consequent precipitation of the mineral load of one or both solutions at their confluence. While this process can be proved in the laboratory, rarely can a positive demonstration be found in nature, for the conditions at the time an ore deposit is being worked are usually entircly differcnt from those that existed when the orebody was formed. For this reason, the present deposition of copper carbonate in the southern end of the Briggs mine of the Calumet and Arizona Mining Co. near Bisbce, Ariz., is of great interest. The developed orebodies in the Calumet and Arizona mines are roughly confined to two broad parallel zones separated at the north by a wedge of Copper Queen ground and at the south by an undeveloped block of Calumet and Arizona ground about 2000 ft. (610 m.) wide. The more westerly zone includes the Irish Mag, Oliver, P. and D., and Cole mines, none of which has been operated since 1919. Much of the water from this division is carried from the 1400-ft., or bottom, level at the southern end of the Cole mine in a long water drift through the undeveloped block to the 1300-ft. level of the Briggs mine at the southern end of the more easterly zone. Most of this water comes originally from outlying areas in the P. and D. mine, passing through parts of the lower. levels of the Cole mine, which are heavily mineralized with iron and copper sulfides. This sulfide zone has been opened up and slowly oxidizing for years. Originally a pure, potable water, the analyses of which are shown under A- in Tables 1 and 2, on its way through the mineralized area in the Cole mine it gathers copper, calcium, magnesium, iron, and aluminum sulfates, a load of dissolved mineral salts almost four times as great as that which it formerly carried; analyses B

Jan 1, 1923

By P. D. Wilson

The genesis of some orebodies has been explained by the mingling and chemical interaction of water solutions of different compositions and the consequent precipitation of the mineral load of one or both solutions at their confluence. While this process can be proved in the laboratory, rarely can a positive demonstration be found in nature, for the conditions at the time an ore deposit is being worked are usually entircly differcnt from those that existed when the orebody was formed. For this reason, the present deposition of copper carbonate in the southern end of the Briggs mine of the Calumet and Arizona Mining Co. near Bisbce, Ariz., is of great interest. The developed orebodies in the Calumet and Arizona mines are roughly confined to two broad parallel zones separated at the north by a wedge of Copper Queen ground and at the south by an undeveloped block of Calumet and Arizona ground about 2000 ft. (610 m.) wide. The more westerly zone includes the Irish Mag, Oliver, P. and D., and Cole mines, none of which has been operated since 1919. Much of the water from this division is carried from the 1400-ft., or bottom, level at the southern end of the Cole mine in a long water drift through the undeveloped block to the 1300-ft. level of the Briggs mine at the southern end of the more easterly zone. Most of this water comes originally from outlying areas in the P. and D. mine, passing through parts of the lower. levels of the Cole mine, which are heavily mineralized with iron and copper sulfides. This sulfide zone has been opened up and slowly oxidizing for years. Originally a pure, potable water, the analyses of which are shown under A- in Tables 1 and 2, on its way through the mineralized area in the Cole mine it gathers copper, calcium, magnesium, iron, and aluminum sulfates, a load of dissolved mineral salts almost four times as great as that which it formerly carried; analyses B

Jan 1, 1923

By Yap Chu-Phay

Although chronologically the Sb-Bi system was the first one studied by the writer, the theoretical basis of the equations used in this paper is fully discussed in the writer's paper on the iron-carbon system,' because he believed that many would be more interested in the iron-carbon alloys. He suggests, therefore, that the reader consult that paper to familiarize himself with the theoretical aspect of the thermodynamic treatment outlined herein. This paper is divided into two parts: Part 'I deals with the Sb-Bi system and Part II deals with the lead-rich side of the Sb-Pb system. Although the former system has not much practical interest now, it has great theoretical interest in that it is the one system that for a long time was thought to have (and under specific conditions still has) an anomalous solidus, which no amount of physical investigation could adequately account for. The latter system, of course, is particularly interesting in the lead-rich end. It will be shown that the thermodynamic method is capable of predicting reliably the equilibrium position of the solidus, and thus acts as a check on the experimentally derived solidus. PART I.—THE ANTIMONY-BISMUTII SYSTEM In connection with his studies in thermoelectric phenomena,-the writer was naturally interested in the system Sb-Bi. In consulting the International Critical Tables2 he found the constitutional diagram shown in Fig. 1 (not including Ôtani's solidus), essentially after Cook,³ who investigated the system carefully by thermal analysis. Note the isothermal crystallization of alloys varying in composition from about 48 per cent, (by weight) to pure Bi. This is anomalous, because, according to the phase rule, in a binary system when only two phases coexist, there is univariant equilibrium; that is, the composition changes with the tempera-

Jan 1, 1931

By Jack White

MUFULIRA Copper Mines, Limited, conducted tests on the concentrator in 1942 to determine which type of ball mill, that is, Conical Trunnion overflow or Cylindrical Grate discharge, produced the greater quantity of finished product at the lowest cost. All the data which follows applies to Mufulira ore and to the particular degree of grinding produced with the classifiers installed at Mufulira concentrator. JACK WHITE, Member AIME, is Concentrator Superzntendent, Mufulira Copper Mines, Ltd., Mufulira, Nortltern Rhodesia. Sun Francisco Meeting, February 1949. TP 2729 B. Discussion of this paper (2 copies) may be sent to Transactions AIME before Feb. 28, 1950. Manuscript received Feb. 28, 1949. Test Procedure: The test was carried out using ball mills No. 1 to 9 (conical trunnion overflow) as the standard with which to compare No. 10 (cylindrical grate discharge mill). The conical trunnion overflow ball mills are 10 ft diam by 72 in., and the cylindrical grate discharge mill is a No. 99. Each mill runs in closed circuit with a Dorr type DSFX classifier 8 ft wide by 30 ft long. The feed is considered as being identical to all ten units. The figures for the test were derived as follows. Dry Tons Milled: For No. 10 unit (cylindrical grate discharge mill) this figure was taken from the ball mill weightometer, which was corrected for error, and then for moisture content. The weightorneter was checked twice a week during the test, and the error did not exceed 3 pct at any time. The moisture was obtained from a 24 hr moisture sample taken by the ball mill operator hourly, and placed in a closed bucket. The sample was cut where the conveyor drops the feed into the ball mill chute. The Mill Sampling Department made a daily moisture determination on this sample. To obtain the dry tons on units No. 1 to 9 the No. 10 figure was deducted from the month's dry tons milled figure, which, in turn, was taken from the crusher weightometer tons corrected for weightometer error and moisture. All tons reported in this test are short tons of 2000 lb. Ball Mill Hours: This was taken daily from the Shift Boss reports giving actual running hours for each unit. Screen Analyses: Coarse Heads (Ball Mill Feed): The monthly composite coarse heads screen analysis, done by the Mill Sampling Department, was used for the minus 200 mesh in the feed to the mills. F. X. Classifier Overflow: The ball mill operators took an hourly 24 hr sample of the overflows of units No. 1 to 9. This was a hand sample, but cut with a special cutter, and is believed to be very reliable. On No. 10 unit, an hourly 24 hr sample, and an hourly shift sample were cut in the same way. These five samples were split, filtered, and dried by the Research Department and were then wet screened on a 200 mesh screen. The average of the three shifts samples on No. 10 unit had to check the 24 hr sample within 1.5 pct to be acceptable. A weighted composite was cut each day from both 24 hr samples, and at the end of each month it was screened as follows: Wet screened through 325 mesh, the plus 325 then screened on a rotap for 15 min through 65, 100, 150, 200, and 325. This was done in duplicate. All splitting, drying, and screening of samples was done by one of the Mill Research staff, to insure accuracy. F. X. Classifier Overflow Densities: These were taken from the Shift Boss reports. Densities were taken by the ball mill operator every hour. Circulating Loads: These were taken a number of times during the test both by direct method (weighing a measured portion of classifier rake sand, and deducting moisture) and by calculation using the formula:

Jan 1, 1951

By Jack White

MUFULIRA Copper Mines, Limited, conducted tests on the concentrator in 1942 to determine which type of ball mill, that is, Conical Trunnion overflow or Cylindrical Grate discharge, produced the greater quantity of finished product at the lowest cost. All the data which follows applies to Mufulira ore and to the particular degree of grinding produced with the classifiers installed at Mufulira concentrator. JACK WHITE, Member AIME, is Concentrator Superzntendent, Mufulira Copper Mines, Ltd., Mufulira, Nortltern Rhodesia. Sun Francisco Meeting, February 1949. TP 2729 B. Discussion of this paper (2 copies) may be sent to Transactions AIME before Feb. 28, 1950. Manuscript received Feb. 28, 1949. Test Procedure: The test was carried out using ball mills No. 1 to 9 (conical trunnion overflow) as the standard with which to compare No. 10 (cylindrical grate discharge mill). The conical trunnion overflow ball mills are 10 ft diam by 72 in., and the cylindrical grate discharge mill is a No. 99. Each mill runs in closed circuit with a Dorr type DSFX classifier 8 ft wide by 30 ft long. The feed is considered as being identical to all ten units. The figures for the test were derived as follows. Dry Tons Milled: For No. 10 unit (cylindrical grate discharge mill) this figure was taken from the ball mill weightometer, which was corrected for error, and then for moisture content. The weightorneter was checked twice a week during the test, and the error did not exceed 3 pct at any time. The moisture was obtained from a 24 hr moisture sample taken by the ball mill operator hourly, and placed in a closed bucket. The sample was cut where the conveyor drops the feed into the ball mill chute. The Mill Sampling Department made a daily moisture determination on this sample. To obtain the dry tons on units No. 1 to 9 the No. 10 figure was deducted from the month's dry tons milled figure, which, in turn, was taken from the crusher weightometer tons corrected for weightometer error and moisture. All tons reported in this test are short tons of 2000 lb. Ball Mill Hours: This was taken daily from the Shift Boss reports giving actual running hours for each unit. Screen Analyses: Coarse Heads (Ball Mill Feed): The monthly composite coarse heads screen analysis, done by the Mill Sampling Department, was used for the minus 200 mesh in the feed to the mills. F. X. Classifier Overflow: The ball mill operators took an hourly 24 hr sample of the overflows of units No. 1 to 9. This was a hand sample, but cut with a special cutter, and is believed to be very reliable. On No. 10 unit, an hourly 24 hr sample, and an hourly shift sample were cut in the same way. These five samples were split, filtered, and dried by the Research Department and were then wet screened on a 200 mesh screen. The average of the three shifts samples on No. 10 unit had to check the 24 hr sample within 1.5 pct to be acceptable. A weighted composite was cut each day from both 24 hr samples, and at the end of each month it was screened as follows: Wet screened through 325 mesh, the plus 325 then screened on a rotap for 15 min through 65, 100, 150, 200, and 325. This was done in duplicate. All splitting, drying, and screening of samples was done by one of the Mill Research staff, to insure accuracy. F. X. Classifier Overflow Densities: These were taken from the Shift Boss reports. Densities were taken by the ball mill operator every hour. Circulating Loads: These were taken a number of times during the test both by direct method (weighing a measured portion of classifier rake sand, and deducting moisture) and by calculation using the formula:

Jan 1, 1951

By J. J. Kramer, W. A. Tiller, G. F. Bolling

The temperatures of solid-liquid interfaces have been measured during the growth of Sn-Pb alloy crystals which exhibited a cellulur substructure. A simple descriptive theory was used in combination with this data and the other measurable growth variables to predict some features of the solute segregation such as the intercell excess concentration and the depth of cell grooves during freezing. The effective distribution coefficient at the tip of a cell, a, was predicted and experimentally found to vary in the range, 1 >a > k0. At the lower limit, the severe segregation that must arise between dendritic cells was substantiated by various observations such as the existence of a second Phase even for alloys of only 0.2 wt pct Pb. ThE cellular morphology of a solid-liquid interface is known to coincide with the formation of a zone of constitutional supercooling ahead of the interface during growth.' The occurrence of various cell structures, (two-dimensional cells, regular cells, dendritic cells), has been quantitatively investigated,'2,4 but the segregation of solute which arises as a consequence of this mode of growth has only been examined qualitatively. An indirect method of obtaining the solute concentration at the tip of a cell cap during solidification has been de-

Jan 1, 1963

By W. G. Matteson

The origin of the salt domes of the Gulf coastal plain has been investigated by many of the most able geologists, but the problem cannot be said to have been satisfactorily solved. Since 1860, numerous theories have been presented, only to be discarded, at least in part, as more complete infomation revealed their fundamental weakness. Real progress toward solution dates from 1902, when Hill1 advanced the theory of secondary deposition of the domal materials from saturated solutions of hot saline waters ascending from great depths under hydrostatic head along structural lines of weakness. Shortly thereafter, Harris,² using Hill's hypothesis as a basis, explained the doming and pronounced uplift associated with these salt cores as the result of forces exerted by growing salt crystals. This was a marked advance over the ideas of Coste3 and Hager,4 since no evidence of igneous intrusives, as they assumed to explain the uplifts, had been found associated with the domes. Harris5 developed his theory until it offered such apparently plausible explanations of so many details of dome phenomena that his hypothesis and conclusions received widespread acceptance, despite some serious objections, and today his theory, somewhat modified, is considered by many able investigators to be the best explanation of the origin of these domes. The immense production of oil per acre, the recognition of the high lubricating quality of the oil, the development and recognition of the efficiency and advantages of oil-burning vessels, with the subsequent exceptional demand for fuel oil, and the resultant advance in the price of coastal crude, have been responsible for a prospecting and develop- 1 Robert T. Hill: Beaumont Oil Field with Notes on Other Oil Fields of the Texas Region. Jnl. Franklin Inst. (1902) 164, 143. 2Gilbert D. Harris: Rock Salt in Louisiana. Louisiana Geol. Survey Bull. 7 (1907) 76. ³E. Coste: Volcanic Origin of Natural Gas and Petroleum. Jnl. Canadian Min. Inst. (1903) 6, 73. 4Lee Hager: Mounds of the Southern Oil Fields. Eng. & Min. Jnl. (July 28, 1904) 78,137, 180. 6Gilbert D. Harris: Geologicel Occurrence of Rock Salt in Louisiana and East Texas. Econ. Geol. (1909) 4, 12.

Jan 1, 1921

By Rollyn P. Jacobson

THE town of Pacific, in Jefferson County, Mo., is 127 miles west of St. Louis. Since the area lies entirely on the flood plain of a cutoff meander of the Meramac River, it was considered a likely environment for accumulation of commercial quantities of sand and gravel. Excellent transportation facilities are afforded by two major railways to St. Louis, and ample water supply for washing and separation is assured by the proximity of the river. As a large washing and separation plant was planned, the property was evaluated in detail to justify the high initial expenditure. An intensive testing program using both geophysical and drilling methods was designed and carried out. The prospect was surveyed topographically and a 200-ft grid staked on which electrical resistivity depth profiles were observed at 130 points. The Wenner 4-electrode configuration and earth resistivity apparatus" were used. In all but a few cases, the electrode spacing, A, was increased in increments of 11/2 ft to a spread of 30 ft and in increments of 3 ft thereafter. Initial drilling was done with a rig designated as the California Earth Boring Machine, which uses a bucket-shaped bit and produces a hole 3 ft in diam. Because of excessive water conditions and lack of consolidation in the gravel there was considerable loss of hole with this type of equipment. A standard churn drill was employed, therefore, to penetrate to bedrock. Eighteen bucket-drill holes and eight churn-drill holes were drilled at widely scattered locations on the grill. The depth to bedrock and the configuration will not be discussed, as this parameter is not the primary concern. Thickness of overburden overlying the gravel beds or lenses became the important economic criterion of the prospect.** The wide variety and gradational character of the geologic conditions prevailing in this area are illustrated by sample sections on Fig. 2. Depth profiles at stations E-3 and J-7 are very similar in shape and numerical range, but as shown by drilling, they are measures of very different geologic sequences. At 5-7 the gravel is overlain by 15 ft of overburden, but at E-3 bedrock is overlain by about 5 ft of soil and mantle. Stations L-8 and H-18 are representative of areas where gravel lies within 10 ft of surface. In most profiles of this type it was very difficult to locate the resistivity breaks denoting the overburden-gravel interface. In a number of cases, as shown by stations M-4 and H-18, the anomaly produced by the water table or the moisture line often obscured the anomaly due to gravel or was mistaken for it. In any case, the precise determination of depth to gravel was prevented by the gradual transition from sand to sandy gravel to gravel. In spite of these difficulties, errors involved in the interpretation were not greatly out of order. However, results indicated that the prospect was very nearly marginal from an economic point of view, and to justify expenditures for plant facilities a more precise evaluation was undertaken. The most favorable sections of the property were tested with hand augers. The original grid was followed. In all, 46 hand auger holes were drilled to gravel or refusal and the results made available to the writer for further analysis and interpretation. When data for this survey was studied, it immediately became apparent that a very definite correlation existed between the numerical value of the apparent resistivity at some constant depth and the thickness of the overburden. Such a correlation is seldom regarded in interpretation in more than a very qualitative way, except in the various theoretical methods developed by Hummel, Tagg (Ref. 1, pp. 136-139), Roman (Ref. 2, pp. 6-12), Rosenzweig (Ref. 3, pp. 408-417), and Wilcox (Ref. 4, pp. 36-46). Various statistical procedures were used to place this relationship on a quantitative basis. The large amount of drilling information available made such an approach feasible. The thickness of overburden was plotted against the apparent resistivity at a constant depth less than the depth of bedrock for the 65 stations where drilling information was available. A curve of best fit was drawn through these points and the equation of the curve determined. For this relationship the curve was found to be of the form p = b D where p is the apparent resistivity, D the thickness of overburden, and b a constant. The equation is of the power type and plots as a straight line on log-log paper. The statistical validity of this equation was analyzed by computation of a parameter called Pearson's correlation coefficient for several different depths of measurements, see Ref. 5, pp. 196-241. In all but those measurements taken at relatively shallow depths, the correlation as given by this general equation was found to have a high order of validity on the basis of statistical theory.

Jan 1, 1956

By J. R. Finlay

Every business man who has reached the age of forty, or perhaps even thirty, must know from his own experience that there are occasional periods of "good times'' and others of "bad times "-booms and panics. Those who give to business some complexion of science have invented a semiscientific name for these alternations-the business cycle-indicating that it is a normal phenomenon which by its own nature repeats itself. The longer one lives and the more one enlarges his own experience by the study of history, the more of these cycles he knows and the more disposed he becomes to take their recurrence for granted. If these alternations can be put into the category of common- places, why not treat them as such? We are in a sharp depression right now, why worry about it? Is there not a certain average value for business that can be depended upon in spite of depressions? By way of rejoinder one might answer that war is the great commonplace of history, but when we get into one we generally find it worthy of attention. In the present case, many a man has lost two-thirds of his income, and he is extremely nervous about finding it again. The Southern Pacific Railroad earnings have dropped 75 per cent in the past year; Pennsylvania, 60 per cent; United States Steel Corp., about the same. The drop in current earnings is

Jan 1, 1932

By Molly Gleiser, John Chipman

The standard free energy of formation of WC was obtained from determination of the equilibrium WC + CO2 = W + 2CO between 1215° and 1266°K. Its uallie is -8340 * 300 cal Per mole over the above range of temperature. AS a part of a program devoted to measuring the stabilities of the carbides, a study was made of the free energy of formation of tungsten carbide, WC. The homogeneity range of this compound is very small,' and it is generally accepted and is dealt with here as a stoichiometric compound. The heat of formation, ?H°f, of WC has been accurately measured by Huff, Squitieri, and snyder.2 The only attempt, however, to measure the free energy of formation of this compound was made by Schenck, Kurzen, and wesselkock3 who brought tungsten carbides into equilibrium with H2 and CH4. Unfortunately their results are not sufficiently accurate nor consistent enough to permit the calculation of free energies. METHOD Heating mixtures of tungsten and carbon powders in hydrogen for 4 days at 1050°C led to formation of some WC without any trace of W2C. It was deduced, therefore, that at least below this temperature W2C will not be formed during experiments with mixtures of tungsten and WC. This was subsequently shown to be correct. The method chosen was the measurement of the equilibrium of the reaction

Jan 1, 1962

By John Griffen

K. F. Tromp (Kerkrade, Holland)—Your assumption that the Dutch State Mines have lead in the development of heavy medium processes—the Barvoys, Loess, Driessen—is not correct. The credit should be given to a Dutch engineer Mr. deVooys, the inventor of the Barvoys process. deVooys started in 1932 in Hiickelhoven, a German but Dutch-owned mine, where he was a director. Several plants on the Continent as well as in Great Britain were erected. The State Mines started their first plant in 1937. They could not get that plant working satisfactorily and built another one. Their process made no headway, and up to 1946 there was only one plant installed, the one at their own pit. Since 1946 they started the cyclone process and only since that time have they been more active, though industrial cyclone washeries are still in their infancy. deVooys sold his patents to the Dutch State Mines in 1946 and this might have given you the impression that the pioneer work had been done by the Dutch State Mines. John Griffen (author's reply)—I wish to thank Mr. Tromp for giving the correct story on the development of heavy medium processes in Holland.

Jan 1, 1952

GEORGE K. BURGESS,* Washington, D. C. (written discussiont).-Professor Sauveur refers to the International Aircraft Standards Board in terns that would indicate his non-familiarity with, the organization and the working of this Board which, of course, is excusable on account of Professor Sauveur's absence in Europe at the time. He implies .that the work of this Board was entirely dominated by American interests, whereas diametrically the opposite was the case. The Board, was organized for the purpose of facilitating purchase in the United States, on the basis of common specifications, by the Allied air, services in the United States, and the Board performed a very valuable service in unify-ing the specifications of Italy, Great Britain, France, Canada, and the United States for such purposes. The proceedings of the Board were car-ried out on the basis of unanimous agreement of the representatives of the five countries and all the members from each of the countries were technical specialists or, had the advice of technical assistants. It would be difficult to find an instance of greater unity of purpose, readiness to' compromise, and efficient production than was shown by this Board, which produced seventy-eight specifications, in the preparation of which representative American manufacturers appeared before the Board.

Jan 12, 1919

THE progress in lead smelting practice in the United States during 1930 has been along previously defined lines. Since most of the material treated is high-grade concentrate relatively high in zinc, practically all the plants have been forced to adopt double sintering. This generally results in there being' no matte fall, and most of the copper in the charge is recovered in the furnace dross. The furnace dross is . smelted with. scrap iron and flux .in small reverberatories, giving a shipping matte or speiss high in copper and low in lead. Details of this reverberatory. furnace practice vary at the different plants. There is a decided tendency toward moreintensive filtration of blast- furnace and sinter fume. Bag capacity has been in- creased by using higher pressures and more frequent shaking.

Jan 1, 1931

All the TECHNICAL PUBLICATIONS and CONTRIBUTIONS published in 1934 are available at Institute headquarters, unless otherwise noted They are also on file in many public, university and technical libraries and, when so indicated in the list, may be found in the TRANSACTIONS Copies of the TECHNICAL PUBLICATIONS have been mailed to those members of the Institute who are registered in the different classes A-Metal Mining, B-Milling and Concentration; C-Iron and Steel Division; D-Nonferrous Metallurgy; E-Insti¬tute of Metals Division; F-Coal Division; G-Petroleum Division; H-Nonmetallic Minerals; I-Mining Geology; J-Mineral Industry Education Division; K-Mining Administration; L-Geophysical Prospecting Other members may obtain copies by writing to the Secretary Copies of CONTRIBUTIONS may also be obtained from the Secretary's office Additional copies are sold at the rate of 1 cent per page, minimum charge, 25 cents Nonmembers may purchase the papers at the prices mentioned

Jan 1, 1935