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By Sidney A. Swensrud

The 24-in. crude-oil line. and- the 20-in. petroleum-products line, built as a war emergency by the United States Government and running from points in Texas to the New York-New Jersey-Philadelphia area, were constructed only because of the inability during the war to continue nor-inal ocean tanker movements from the Gulf Coast to the East Coast. The postwar disposition of these lines may be considered as one of the important problems of the postwar readjustments in the oil industry, if not the most important one. In the first place there appear to be many complications in keeping the lines in crude-oil or petroleum-products service. This conclusion was reached also in a study by T. E. Swigart, President of Shell Pipeline Corporation.' Since the lines are too largc for any one company to utilize, and since it appears likely that a surplus rather than a deficiency of tankers will exist after the war, most companies probably will feel that they can achieve lower costs and more satisfactoiy results from the resumption of tanker movements to the East Coast rather than by endeavoring to take over or utilize the capacity in the large pipe lines under some tariff-rate structure. As for using the lines for making deliveries to the middle west or central eastern areas, it would appear that when the war is over and normal transportation arrangements can be resumed, there will be no need of any extra capacity for such deliveries. Therefore, the War Emergency lines could be utilized for this purpose only if privately owned pipe lines and other transportation facilities were to be displaced. Against this rather unprepossessing prospect for use in petroleum or product service is the fact that at or near the source of the lines lie the greatest developed gas reserves in the world, for much of which there is at present no satisfactory market outlet; and at the other end of the lines lies one of the greatest concentrations of population in the world, which is not now served by natural gas. These who have been fortunate enough to use natural gas can have little doubt of its desirability as a domestic fuel. An analysis of the market potentialities and comparison with other areas where natural gas is being distributed, and where it has displaced manufactured gas, makes it seem clear beyond question that the full capacity of both of the large-diameter lines could be fully utilized in this service, and this without creating any undue drain upon the gas reserves of the nation. On the basis of an estimated capacity of roo to 120 billion cubic feet per year, the gas that might be marketed through these lines would amount to only 3 to 4 per cent of the total con-

Jan 1, 1944

By E. W. Steele

In the copper-casting department of a modern electrolytic copper refinery there are two kinds of casting furnaces: the anode, for casting crude copper into anodes for electrolysis; the refined-copper, for casting the cathodes resulting from electrolysis into market shapes, such as ingots, wire bars, and cakes. Both furnaces are reverberatories of practically the same general design and are operated intermittently, putting through a charge normally in 24 hr. The treatment of the copper in the two furnaces is similar, in that oxidation followed by skimming and reduction (poling) is carried on in both; but in the refined-copper furnace, the work must be done with greater care and it is of extreme importance that not the slightest trace of impurity be introduced into the copper. The furnaces usually hold from 150 to 300 tons of molten copper, which constitutes the daily charge. Except in the case of furnaces in the Lake district, where the concentrates from native-copper ores are charged through the roof, the furnaces are charged through the side doors by charging machines similar to those used in open-hearth steel practice. In 1916, at the Perth Amboy plant, of the American Smelting & Refining Co., located at Maurer, N. J., a study was made of the possibility of firing the copper refinery furnaces with pulverized coal instead of by hand. The proposed method possessed obvious advantages over hand firing and coal was a much cheaper fuel than oil at that time. However, there were several objections to its use, the principal ones being the possibility of increasing the sulfur content of the refined copper and the additional slag that might be produced from the ash. The increase of the sulfur content of the refined copper was the more serious, as more than 0.002 per cent. sulfur is objectionable. Any increase of the slag would be expensive as the copper in this slag would have to pass again through the entire smelting and refining process. It was thought that certain modifications in operations and furnace conditions, which will be described later, would overcome these objections SO the proposition was discussed with a manufacturer of coal-pulverizing equipment. He was uncertain concerning the use of pulverized coal

Jan 1, 1925

By O. Cuscoleca

The Austrian plants at Donawitz and Linz were the first to blow steel with high purity oxygen. The paper shows how the process was developed and gives a survey of the results achieved to date. Compared with open hearth steel of equal quality, the obvious advantages of oxygen steel are the low investment and conversion costs. The nitrogen content of oxygen steel is not higher than that of good open hearth steel. Rimmed and killed steel products made by the oxygen process are superior to rimmed and killed steel products made by the best open hearth process. TWO new steel plants using the principle of making steel with high purity oxygen went into operation in Austria, one at Linz (Vereinigte oster-reichische Stahlwerke) in November 1952 and the other at Donawitz (dsterreichisch-Alpine Montan-gesellschaft) in May 1953. An estimated 330,000 metric tons were produced by the two plants in 1953, the first year of operation. In 1954 production by Austrian plants- using the high purity oxygen approach will be raised to 450,000 metric tons. This will be in addition to facilities in Huckingen (Man-nesmann A. G., Düsseldorf, Germany), those planned and under construction at Hamilton, Ontario, Canada (Dominion Foundries and Steel, Ltd.), and elsewhere. It is expected that by 1955 a total capacity of one million tons of high purity oxygen steel will be available. At the close of the last century, because of increasing availability of scrap, open hearth steel production forged ahead at an ever increasing pace. This caused world steel production to rise faster than pig iron production and finally to overtake it. In 1911 65 million tons of steel were produced against 64 million tons of pig iron. World steel production was 209 million tons in 1951, while pig iron output was only 147 million tons. The 1951 breakdown for steel shows 118 million tons made from pig iron, while the balance, 91 million tons or 44 pct of the total tonnage of steel produced, was made from scrap. This increase in crude steel production on a basis of high scrap consumption led to the world market scrap shortage and soaring scrap prices. In the United States and other nations, production of converter steel has fallen far behind that of open hearth steel. The surplus of processing scrap, un-absorbable by converting mills and thus a welcome source for open hearth and electric melting shops in the past, together with regular scrap purchases, no longer can meet requirements of both open hearth and electric steel production in Europe. In addition, recent modification of the basic bessemer process, blowing with oxygenated blast, substantially raised the scrap capacity of these plants. Any further expansion of world steel production will necessitate utilization of self-containing processes in regard to scrap because of the shortage.

Jan 1, 1955

[Officers JOHN CHIPMAN, President W. R. HIBBARD, JR., Past President C. C. LONG, Vice President T. D. JONES, Treasurer R. W. SHEARMAN, Secretary D. C. JOHNSTON, Assistant Secretary]

Jan 1, 1961

By P. J. Clifford, A. B. Brown

The development of computerised mine planning has been hindered by the cost of processing the large data bases associated with mineral deposits and the inherent inconvenience of performing an interactive process on a time-shared computer. A dedicated computer is ideally suited for the purpose but reasonably priced micro/mini-computers have not had the capacity to store the volume of data or the processing capability required. Hardware development has cleared the way for the development of truly interactive mine planning software, covering the complete range of activities associated with mine planning, from geological assessment to short-term scheduling of operations, incorporating them into a single system using a common database. The integrated system, comprising software and dedicated hardware, adds previously unattainable speed, flexibility and clarity to the planning process because it has been tailored exclusively for that purpose.

Jan 1, 1983

By Eugene McAuliffe

NO physical impairment can be more serious than the partial or complete loss of sight. With reasonably good eyesight, a person is equipped to care for life and I limb, provided a rational measure of t caution is manifested. When the sight of one eye is lost or badly impaired, one-half of this God-given asset is gone, and extreme care must be taken to prevent the tragedy of total darkness that closes out the beauty of sky, field and mountain, the faces of relatives and friends, and either removes entirely or in part one's capacity to produce and earn. During 1933, The Union Pacific Coal Co., operating ten coal mines in Wyoming, decided to undertake a visual survey of all of its mine operating officials and employees. Although the cost of workmen's compensation paid because of eye injuries was material, the management was more deeply concerned with the social loss and the suffering resulting from the many eye injuries. As every element of coal production cost must be scrutinized, accurate data on all accidents, with the workmen's compensation paid therefor, are carried forward monthly. The number of accidents to eyesight and the resultant compensation paid are shown in Table 1 for nine calendar years:

Jan 1, 1934

By C. EDWARD STAFFORD

A Discussion of the paper by Mr. James P. Roe which was read at the Washington meeting, May, 1905. MR. C. EDWARD STAFFORD, Chester, Pa.:-During all my business life, I have been engaged in the manufacture of Bessemer and open-hearth steels, but, during my long connection with the Shoenberger Steel Co. of Pittsburg, I had some experience in the manufacture of high-grade puddled iron for horse-shoes and in the making by Dr. Otto Wuth's process extremely pure low phosphorus puddled blooms (analyzing from 0.005 to 0.01 per cent. of phosphorus and sulphur), which were melted with low-phosphorus pig-iron in acid open-hearth furnaces to make extra locomotive fire-box steel. I have also seen the Dank's puddlers in operation at different times and places, notably where they were most successful, at the Otis Steel Works, Cleveland, Ohio; then under the management of our friend, Mr. S. T. Wellman. These Dank's blooms were made solely for open-hearth melting-stock to which they were well adapted ; the unavoidable presence of bits of ore-fix imbedded in the mass of the, metal always prevents the profitable manufacture of merchant iron from Dank's blooms. With the experience just described, I was to some degree in position to value fairly the means, methods and results of Mr. Roe's mechanical puddling from the metallurgical or technical and economic points of view, when given an opportunity by Mr. Roe to see his puddling furnace or machine in operation in Pottstown, Pa. Briefly, the furnace, with water-cooled bottom, is rectangular in plan, about 20 by 8 ft. in the clear, suspended by trunnions at the middle of the long sides, at a. height of 17 or 18 ft. above the general level; the oscillation (65° each way from the vertical) is accomplished by geared segments (attached to the downward-projecting side or trunnion-plates) with which engage pinions driven by a reversing engine. The whole section

Sep 1, 1905

By O. Mellgren, A. M. Gaudin, P. L. De Bruyn

In the January 1956 issue: TP 4137B. Adsorption of Ethyl Xanthate on Pyrite. By A. M. Gaudin, P. L. de Bruyn, and Olav Mellgren. P. 65. Since P. L. de Bruyn is now a member of the AIME, the word "associate" should be removed in describing his status. The address of the third author, Olav Mellgren, should read: 74-2 Chingola, N. Rhodesia. P. 68, second paragraph, last line: the word "300-fold" should be replaced by "3000-fold." Also in the January 1956 issue: TP 4158B. Energy Transfer by Impact. By R. J. Charles and P. L. de Bruyn. The authors wish to express their disapproval of the omission of the abstract from the article, since they believe that an abstract fulfills a very important function in every paper.

Jan 1, 1957

By J. R. Linney

THE Eastern magnetite industry has not failed in its contribution to the war program during the past year. Man-power shortage was the critical problem in maintaining production and for the last half of the year, owing to lack of man power, it was necessary for some mines to change from seven to six days per week schedule. At Cornwall, Pa., the mine operated by the Bethlehem Steel Co. produced approximately 2,000,000 tons of crude ore and 1,200,000 tons of iron ore concentrates, a decrease of about 10 per-cent compared with the previous year. Railroad haulage in the open-pit at this mine was discontinued, being replaced by Mack trucks of approximately 30 tons' capacity. At the Mt. Hope mine in New Jersey, the Warren Foundry and Pipe Corp. produced about 195,000 long tons of crude ore obtaining 70.000 long tons of lump ore and 35,800 long tons of concentrates. An additional 24,500 long tons of concentrates was produced from a stock pile of 47.000 long tons of crude ore accumulated during the latter half of 1943, following the fire in their old dry mill. All of this material was handled through their Brown

Jan 1, 1945

The fall meeting of the Coal Division t was held at Pittsburgh, Oct 21-22, with the William Penn Hotel as headquarters The registration totalled 168 Secretary Parsons, George Otis Smith and J T Breunich were the official representatives from Institute headquarters Eighteen papers were presented There were five sessions altogether Monday morning and afternoon were devoted to papers on miscellaneous subjects, on Thursday morning there were two sessions, one on combustion of coal, the other on miming subjects, and on Thursday afternoon the outstanding feature of the meeting occurred when the members of the Division met in the Cathedral of Learning, University of Pittsburgh, to hear the prize-winning papers read by J F Bottomley, of Harrisburg, I11 , and William Bellano, of Crested Butte, Colo All the students of the School of Mines at the University attended this session The informal

Jan 1, 1937

COMMITTEE IN CHARGE SPENCER PENROSE, Chairman A. E. CARLTON, Chairman Finance Committee GEORGE M. -TAYLOR, Vice-chairman. J. DAMSON HAWKINS, Secretary DENVER COLORADO SPRINGS Finance Finance T. B. STEARNS A. E. CARLTON RICHARD A. PARKER SPENCER PENROSE T. B. BURBRIDGE GEORGE M. TAYLOR A. L. BLOOMFIELD, Treasurer Arrangement Registration DAVE G. MILLER LOREN C. LENNOX FRANK BULKLEY HORACE F. LUNT GEO. E. COLLINS J. M. TIPPETT Entertainment Arrangement and Entertainment F. H. BOSTWICK GEORGE M. TAYLOR F. E. SHEPARD J. D. HAWKINS HOWLAND BANCROFT A. E. CARLTON B. P. MORSE A. L. BLOOMFIELD J. G. PERRY THOMAS B. CRONE E. P. ARTHUR ETIENNE A. RITTER CRIPPLE CREEK PUEBLO THOMAS B. CRONE J. F. WELBORN E. B. ARTHUR H. B. CARPENTER N. S. GREENSFELDER L. B. EAMES A. E. CARLTON F. ROBINSON B. F. HILL J. G. WILLIS

Jan 8, 1918

By W. Evans, C. E. Ells

The agglomeration of hydrogen in pure aluminum and A1-Mg alloys has been studied through use of hydrogen introduced into the metal by cyclotron proton irradiation. Both the growth and dispersal of the agglomerates have been followed by metal-lographic techniques. During the cyclotron irradiation, agglomeration occurs at temperatures i 100°C for hydrogen concentrations as low as 1 ppm. On heating at elevated temperatures, 300°C to 600°C, intragranular agglomerates first coarsen and then disperse. The agglomerates formed at grain boundaries are much larger than the intragranular agglomerates; with hydrogen concentra- tions > 10 PPm, heating for 1 hr at 500°C results in extensive grain-boundary cracking. The hydrogen agglomerates have been shown to inhibit grain growth, but no inhibition of recrystallization has been observed. The ability of hydrogen to enter aluminum at a free surface, combined with its high-diffusion rate at elevated temperatures, accounts both for growth and dispersal of the agglomerates. Irradiations at elevated temperatures give results consistent with the explanation proposed for agglomerate behavior on post-irradiation heating. 1 HE formation of hydrogen-filled bubbles, or blisters. in aluminum and its alloys has been studied for over' thirty years. The work up to 1952 has been reviewed by Kostron' and since then Ransley and

Jan 1, 1963

By W. G. SWART

THE best estimate on reserves of iron ore in the Lake Superior district is that made, in 1920, by Mr. R. C. Allen, amounting to 2,947,225,000 tons of assured and probable ore. This includes direct- shipping or so-called merchantable ores, and those capable of beneficiation by demonstrated processes. De- ducting from this the 287,000,000 tons shipped since 1920, leaves a present reserve of approximately 2,500,- 000,000 tons, or; about 50 years' supply. The assured ore in this estimate is given as 1,560,500,000 tons, which checks Mr. Lake's estimate of 1,528,948,000 tons, or about 30 years' supply. This is not a long time in the life of the steel industry, and it can be readily appreciated that the matter is important enough to war- rant the attention it is beginning to receive. The first question that engages our attention is, What is merchantable ore? In 1902 the average of all Mesabi shipments was 56.07 per cent iron and 4.35 per cent silica. Twenty-five years later it had dropped to 51.99 per cent iron, with silica up to 7.92 per cent. It has remained around these figures for' ten or twelve years and, except for a probable rise in silica, can stay there for an indefinite period. Most of these figures I am giving cover the Mesabi Range. Including the other ranges does not change the figures greatly, and the Mesabi Range commands the situation, since it produces about 65 per cent of the total annual tonnage and, according to Mr. Allen, contains 81 per cent of the assured reserves, 50 per cent of the probable reserves, and 66 per cent of both the assured and the probable reserves.

Jan 1, 1926

By C. G. Dunn

With respect to theories of recrystalliza-tion in metals plastically deformed. it has been said that the present status of this subject is far from satisfactory.1 It may also be said that before any mechanism of recrystallization for metals and alloys can be set forth in a satisfactory manner, there must be made available considerable data on orientation changes that occur during the deformation and recrystallization processes. Although extensive data have been published on recrystallization in single crystals and in poly-crystalline specimens, more results of a type that can be classified according to simple orientation changes would be desirable in this complex field. It might even be said that before classifications are made according to types of orientation changes, it may be possible to classify a considerable amount of data into certain kinds of orientation states if groups of common or nearly common orientation occur. Methods for computing the probability of occurrence for various types of groups have been published2 and it has been pointed out in particular that it should be possible to analyze orientation data for high-order twin relationships between old and new grains even when agreement is not at all exact. In this connection, work on recrystallization in silicon ferrite reported in a paper concerned with complex groups of annealing twins3 indicated that some data were consistent with primary nucleation OCcurring according to a second-order or a third-order twin transformation. However, further work in this latter direction was definitely needed. It is, therefore, the purpose of the present paper to report data and analyses for primary nucleation in silicon ferrite following small deformations that have been carried Out at the Pittsfield Works' Laboratory of the General Electric Co. Analyses have been made with the aid of standard groups of twins that are reported elsewhere.4 PReparation oF Specimens and Experimental Procedure The material used in the present investigation was taken from the same heat of steel as that .used in a prior report.3 The finished strip in both cases was made by the Allegheny-Ludlum Steel Corporation according to methods that produce a high degree of preferred crystal orientation. Samples with large grains had the following composition: 3.45 per cent Si, 0.003 C, 0.008 P, 0.020 S, 0,075 Mn, 0.03I A1 and 0.072 Cu. Thickness of specimens was 0.012 inches. Plastic deformation was produced by cold-rolling the samples on a mill with 8-in. diameter rolls, the plane of the sample in each case coinciding with an XY plane (the plane of projection for the stereo-graphic plots) and the elongation occurring in the X direction. In general, elongations were held to about 3 or 4 per cent.

Jan 1, 1945

By S. E. Clay

In the chemical reaction control regime employed in the laboratory dissolution experiments, calcined trona ore dissolves in aqueous solutions according to a first order, irreversible reaction rate. The study showed that the reaction is first order with respect to solution NagCO3 concentration. The activation energy was determined to be 20.233 kJ/g. mol with a rate constant equal to 1235 mm/s (2917 in. per min). The dissolving particle may be described by shrinking particle behavior.

Jan 1, 1986

By Michael Epstein, Daniel E. Rosner

Fume nucleation sufficiently close to vaporizing suvfaces can augment net vaporization rates into cooler environments. Environmental conditions favoring large vaporization rate enhancements are briefly discussed and a previous theoretical treatment of this nucleation phenomenon is generalized to account for the self-regulating effect of condensalion-heat release within the boundary layer. Despite kinetic limitations on homogeneous nucleation, and latent heat release, non-diffusive condensate removal processes appear to make possible large enhancements in steady-state vaporization rates, provided surface temperatures are well below the boiling point. When condensed phases vaporize (or dissolve) into cooler media, the diffusion-limited mass loss rate can be strongly influenced by the process of nucleation/con-densation (or precipitation) within the thermal boundary layer. This condensation process (which typically leads to mists or fumes in the case of evaporation into cooler gases) has the effect of steepening the vapor pressure profiles near the evaporating surface, since the condensation zone acts as a vapor sink. However. the resulting enhancement in the diffusion-limited evaporation rate can be estimated (as first done by Turkdogan1 for the case of molten iron/nickel alloys evaporating into helium) only if one has independent knowledge of the critical supersaturation, sCrit(T), required to homogeneously nucleate the vapor.* In a recent reformulation and generalization of the theoretical model of Ref. 1 it has been shown that, when log sCrit is approximately linear in reciprocal temperature, rather simple expressions can be derived4 for the ratio of the actual rate of vaporization j" to either the minimum (no condensation) rate j"min, or the maximum (equilibrium condensation) rate j"max In the present communication we wish to briefly report on further developments and implications of the formulation of Ref. 4, with emphasis on i) environmental conditions favoring large enhancements in vaporization rate, and ii) the self-regulatory influence of condensation heat release (neglected in Refs. 1 to 4) on predicted vaporization rates. Additionally, we take this opportunity to correct several misprints appear- ing in Ref. 4, and comment on Elenbaas's recent criticism5 of Ref. 1. MAXIMUM POSSIBLE VAPORIZATION RATE IN PRESENCE OF CONDENSATION A nonequilibrium theory is of interest because of the very large difference between the minimum (no condensation) and maximum (equilibrium condensation) vaporization rate. The magnitude of this maximum possible enhancement can be shown quite clearly by combining a result of Refs. 3 and 4 with the fact that for most liquids there is a simple relationship between the molar heat of evaporation, A, and its boiling point, i.e., A/(RTBp) = C, where the constant C, often called the Trouton ratio, takes on values not very different from 11.* More generally, for any substance (including The Trouton ratio (which for water is 13, for methane, 10, and so forth) will be recognized as the ratio of the molar entropy change upon vaporization (at TBP or Ttransf) to the unlversal gas constant R. Its near constancy reflects the fact that the change in atomic order upon vaporization depends only weakly on the kinds of molecules involved. those that sublime under ordinary conditions) we can define a characteristic transformation temperature. Ttransf, by a relation of the form Ttransf =A/(CR), and then examine the maximum possible evaporation rates as a function of how far removed from Ttransf are the surface temperature, Tw, and ambient temperature, T. Subject to the assumptions: 1) equilibrium vapor pressure, pv,eq, everywhere small compared to prevailing total pressure, p, and 2) negligible effect of condensation heat on temperature profile, the maximum enhancement ratio was found (Eq. [17], Ref. 4) to be: where, for most vapors, Nu/NuD (the ratio of heat transfer coefficient to mass transfer coefficient for the same configuration) is a number near unity.* Ex- *An alternative derivation of the Nu = NuD special case of this equation. revealing its validity for arbitrary velocity/temperature profiles in a laminar boundary layer, is given in Ref. 3. amining this result for a "Trouton substance", one obtains the results shown in Fig. 1, constructed for C = 11. Since we are concerned with vaporization enhancements (j'max/J"min > 1) at surface temperatures below Ttransf, this area of interest is shown unshaded. One notes that at a fixed ambient temperature (hence, T/TtranSf) there is a unique surface temperature, 2T , at which j"max/j"min attains its peak value; moreover, the peak enhancement ratio, see dashed locus. Fig. 1, is: (NuA/NuD)(C/4)(Ttransf/T,). Hence, if Nu = NuD, when the ambient temperature is less than 1/4 of TtranSf the peak enhancement exceeds the Trouton

Jan 1, 1969

By W. B. Heroy

ONLY through the mineral fuels can large amounts of energy be transported to great dlstances and stored for long periods for future use. Coal has the advantages over oil of greater safety of handling and smaller losses in storage. But oil is, in the present stage of technical advancement, the more economical source of liquid fuel for internal-combustion motors. No method for direct use of coal in such motors has been developed that can compete with petroleum products. The automoblle engine and the airplane motor are designed to make the most effective use of gasoline.

Jan 1, 1944

By AIME AIME

BY COMBINING the sessions on reduction and refining of copper, lead and zinc it was possible to devote an entire day to nonferrous metallurgy. Four interesting papers were presented at the morning session and four more in the afternoon. In the discussion of papers on copper, F. R. Pyne acted as chairman, with H. M. Shepard as vice-chairman, whereas for those on lead and zinc, F. F. Colcord acted as chairman, with C. R. Hayward as vice-chairman. The paper by P. D. I. Honeyman on the smelting of raw concentrates in the reverberatory furnace was presented by Mr. Pyne and discussed by Messrs. Mazany and Hayward. The interesting paper by E. S. Bardwell, com- paring the use of various fuels in copper-refining furnaces at Great Fails, Mont., was presented by Mr. Shepard and discussed by Messrs. Boggs, Gronningsater and Hayward. That by R. G. Knickerhocker, describing the stationary basic copper converter at Messina, Transvaal, was presented by Mr. Pyne, together with a written discussion by c. R. Kuzell, of the United Verde Copper co. It was an interesting illustration of how well-known processes may sometimes be modified to fit into unusual conditions.

Jan 1, 1932

By G. A. Parks, C. Kovacs

The xanthate flotation of chrysocolla can be improved by preheating the ore to 500° to 600°C. Addition of water vapor reduces the preheating temperature required. The temperature range of flotation improvement correlates well with the range over which dehydroxylation occurs. This observation is consistent with changes in the structure and properties of the mineral as detected by measurement of solubility, D.T.A., T.G.A., X-ray diffraction, and infrared absorption and with recently proposed explanations of chrysocolla flotation. A brief experiment by one of the authors several years ago showed that exposure of chrysocolla to high temperature water vapor resulted in increased recovery by subsequent xanthate flotation. Recently renewed interest in flotation and thermal properties of chrysocolla1-5 prompted further study of this effect and more detailed reporting.6 This paper explores the response of pure chrysocolla recovery in Hallimond tube flotation tests to the time and temperature of exposure and to changes in the water vapor pressure. Brief attention is paid to the effects of such treatment on accessory minerals. A single experiment with flotation of chrysocolla from an ore is reported. MATERIALS Chysocolla from Inspiration, Gila County, Ariz. was crushed in a porcelain mortar, cleaned of visible and magnetic impurities, and screened to obtain -48 +65 mesh (Tyler) material for flotation test work. The clean material contained 28.5% Cu and was identified as chrysocolla by comparison of X-ray diffraction, D.T.A., and infrared absorption data with that reported for similar materials by others.4,5,7 Samples of malachite and chalcopyrite, prepared in a similar way, were also identified by X-ray diffraction. The sources of these materials are unknown. A sample of chysocolla-bearing oxidized copper ore from Pima, Ariz. was crushed and dry ground for thermal activation and subsequent flotation. PROCEDURES Activation: The apparatus used for exposure of materials to high temperature water vapor is illustrated in Fig. 1. The furnace temperature was controlled to ±5°C Water vapor pressure was controlled by pre-saturating a nitrogen carrier stream with water in an adjustable thermostatted saturator (multiple bubbler). A water manometer and capillary orifice flow meter were used to measure nitrogen flow rates for activation and for subsequent Hallimond tube tests. Gas flow rate and temperature were adjusted prior to introduction of samples. Exposure time was measured from the moment of introduction of the sample to the furnace, hence includes an initial drop below the control temperature. After heating, the samples were removed from the furnace and stored at room temperature in air. Representative samples of activated materials were examined by X-ray diffraction and infrared absorption.

Jan 1, 1967

By H. H

This paper describes the milling practice and operating results of the recently installed heavy-media separation plant of Barton Mines Corporation, the world's largest producer of garnet. This pioneer application of heavy-media separation (sink-float) processes for the beneficiation of a nonmetallic ore is unique in many respects, the details of which will be apparent from the following presentation. Characteristics of the Ore The property is on Gore Mountain, 5 miles west of the village of North Creek, New York, and 11 miles by road. The altitude of the mine is approximately 2800 feet. The valuable mineral, garnet, occurs in a surface deposit, the ore body being about ¾, mile long and varying in width from 50 to 300 ft. The garnet, principally almandite, Fe3Al2 (SiO4)3, occurs in a metamorphic rock of uncertain origin. The gangue mineral is principally hornblende, which constitutes from 40 to 80 per cent of the rock. The remainder of the gangue is divided between plagioclase feldspars and hypersthene, with smaller amounts of biotite, apatite and pyrite. The garnet content of the ore body varies from 5 to 20 per cent of the mass and averages about 10 to I2 per cent. The garnet occurs as crystals, mostly imperfectly developed, known locally as "pockets." These crys- tals vary in size from a fraction of an inch to a foot or more in diameter. Occasionally crystals have been found up to 30 and 36 in. in diameter but they average 4 to 6 inches. Nearly every crystal of garnet is surrounded by a rim of coarsely crystalline hornblende. The quarry faces are striking in appearance, showing crimson-red garnet crystals with their coal black rims scattered over a grayish black background. The specific gravity of the garnet is 3.8 to 4.1 while that of the hornblende ordinarily is 3-07 to 3.24. Some specimens of very dense hornblende have been found with a specific gravity as high as 3.40. The garnet crystals are laminated in structure, and readily cleave into flat, tabular pieces with sharp, chisel-like edges. Even when crushed to a very fine size, the garnet retains this flat, sharp, slivery grain shape. This characteristic, together with its hardness and toughness, gives it its value as an abrasive- Former Operations Mining operations have been carried on for 60 years. Until 1923, only the oxidized (soft rock) section of the ore body was mined. The oxidation, which affected the garnet only slightly, made possible the removal of the garnet from the rock by hand after it was blasted down, using small hand picks. In 1923 a mill was erected on the property, and was rebuilt and redesigned in 1928. Before the adoption of heavy-media separation, concentration was effected by

Jan 1, 1943