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By AIME AIME

A FALL meeting that should have repercussions both in the "Transactions" and MINING AND METALLURGY was that of the Industrial Minerals Division (Nonmetallics) at Wilmington, Oct. 21-23; headquarters, Du Pont Hotel. The sixteen technical papers and two addresses were substantial and interesting. Moreover, in every instance but one, the author made the presentation, and the one exception must have been next of kin because the ensuing discussion indicated his command of the subject. The meeting schedule clicked at every turn, thanks to Dr. Gillson, chairman of the local committee, and even the four field trips adhered to the time table. The program pre-empted morning, noon, afternoon and night two general luncheons, two dinners, and an evening technical session reminding one of the Annual Meeting. Only the registration was disappointing - about 80.

Jan 1, 1943

By AIME AIME

THE PAPER, "Surface Effects on Assay Beads Caused by Metals of the. Platinum Group," presented by J. L. Byers, before the Institute of. Metals Division at the February meeting of the Institute, is the subject of interesting discussion, an abstract of which follows. The original paper is available at Institute headquarters as a Preprint. Member-What assurance have you that the percentage of metals, as stated, is really an accumulation?

Jan 1, 1932

By G. Hileman

At present there are three fields in commercial exploitation in the Argentine. In order of production they are: (1) Comodoro Rivadavia, (2) Salta, (3) Plaza Huincul. Comodoro Rivadavia.—This field is on the coast of the Territory of Chubut in the southern part of the republic. It is being developed and exploited by Yacimientos Petroliferos Fiscales, the government oil entity, and five private companies. The immediate coastal portion of the field, which embraces the original discovery area, is almost completely developed. This is especially true of the original government reserve and one private property. The Y.P.F. has extended its explorations and developments westward to Escalante, 27 km. distant on the state railway. This extension has been the most active and prolific section of the field for the past three years. The government has also continued its exploration drilling in the region lying south of Colonia Sarmiento and east of the Rio Senguer. Private companies have not been able to extend their operations beyond the claims they had in process of acquisition in 1924, when the government reserve areas were established. The Y.P.F. is the major producer of the field and employs modern methods and appliances. Practically all its drilling and pumping operations are electrically operated, from a central power plant. In view of t'he scarcity of water supplies, this facilitates operations and is an economic factor of considerable importance.

Jan 1, 1934

By S. Norton

GEORGE C. FOOTS, Port Henry, N. Y. (written discussion).-The paper by Mr. Norton and Mr. LeFevre will bear the most careful consideration by all interested in the iron business, particularly in the East. There is much information contained therein which should be emphasized. The idea of handling iron-bearing rock in quantities comparable to the porphyry coppers does seem at first blush to be beyond the pale of commercial possibility. Yet, today in the Adirondack region 25 per cent.

Jan 4, 1917

By J. E. Berg

THE geology of the Coeur d'Alene mining district is so familiar to every one interested in mining that I will only note as an introduction that the main producers are mines whose orebodies lie in the Revett or Burke quartzites ; that the known orebodies in the eastern part of the district all lie north of the Osburn fault; that the Prichard formation is quite generally looked upon as being unfavorable for lead deposits ; that the monzonite intrusive mass extending north from Gem to Sunset Peak, and over into Cedar Creek divide, is considered to have been the prime agent in the crea-tion of our orebodies, and that diabase dikes are a quite common feature at most of the properties with which I am familiar. Some of the exceptions to these statements may be mentioned. The Interstate-Callahan mine is considered the exception disproving the alleged relation between large ore-deposits and the Prichard formation, but this property was primarily a zinc producer, with lead secondary, though of sufficient tonnage to be a valuable product. A second interesting occurrence in the Prichard worth calling to your attention is the Jack Waite property, on Tributary Creek, north of Murray. This vein lies at a low horizon in the Prichard forma-tion, and the ore differs essentially from others in the same horizon elsewhere in that it is a clean, medium to coarsely crystalline, lead ore carrying very little zinc, about one ounce silver to ten units lead, and is accom-panied by a clean quartz gangue or vein filling. I believe that quartz was the primary mineral in the fissure, and that the lead ore was deposited in the vein as a replacement of the quartz.

Jan 7, 1927

By Howard Martens, Pol Duwez

XPERIMENTS were performed on a Cr-Fc alloy Econtaining 44.7 pet Cr in order to determine the heat evolved during the transformation of the a solid solution into the s phase, and the change in volume accompanying the transformation. Since previous measurements on the rate of formation of a from s indicated that the reaction was quite fast as soon as the equilibrium temperature of 820°C was exceeded by some 50°, standard thermal analysis experiments were performed on heating specimens of s at the rate of approximately 40°C per sec. A definite thermal arrest was observed at 870"C, Fig. 1. This result indicates that the reverse seaction of into a is exothermic. From the heating curve of Fig. 1, taking 15°C per sec as the heating rate in the neighborhood of the transformation, 2.4 sec as the time for transformation, and assuming that the specific heat of the alloy at 850°C is an average between iron and chromium, namely 9.5 cal per mol per "C, the latent heat of transformation is approximately 342 cal per mol. The order of magnitude of this latent heat was also obtained by comparing the heating curve of Fig. 1 with a similar curve obtained with pure iron under identical experimental conditions. It was found that the length of the thermal arrest for s was about 1.8 times as long as that for iron. Since the latent heat of the a to 7 iron transformation is 203 cal per mol1, 2 the latent heat of it to a would be 365 cal per mol, which is in relatively good agreement with the value determined from the heating curve. For the determination of volume change, thermal expansion curves were recorded using a specimen containing 44.7 pet Cr and completely transformed to cr by previous treatment. The curves were recorded at a rate of heating of about 4°C per min and at approximately 840°C a sharr, increase in length of about 0.08 pet took place. Fig. 2. It is therefore established that the specific volume of a near the transformation temperature is about 0.24 pet smaller than that of a, and consequently, when the s phase forms in an a matrix, it would tend to shrink away from the matrix. Since the s phase is known to be extremely brittle, these results offer an explanation for the microscopic cracks often observed in the a phase under the microscope. The results of this study are in qualitative agreement with previously published data on stainless steel 19-9DLa and on a Cr-Fe alloy containing 45 pet Cr.' The increase in density due to the transformation from n to s given in ref. 4 is 0.90 pet. These measurements, however, were made at room temperature. whereas the presently reported 0.24 pet is the change at the temperature at which the transformation takes place during heating. In the graph of Fig. 2, the percentage change in length that would be observed at room temperature is given by the length X, which is about 0.27 pet. This would correspond to 0.81 pet in volume change. Acknowledgment This work was done at the Jet Propulsion Laboratory, California Institute of Technology, under Contract No. DA-04-495-ORD-18 with the Army Ordnance Corps, Washington, D. C. The authors wish to thank this agency for permission to publish the results of this investigation. References I H. Klinkhardt: Measurements of True Specific Heats at High Temperatures. Annalen der Physik (1927) 84, pp. 167-200. - H. Esser and W. Runghardt: Influence of the Method, of Dctcrmination on the Measured Heat Content of Iron. Archtvo ffur Dct Eisenhiittenwesen 11934) 8, pp. 37-38. J. J. Gilman, P. K. Koh, and 0. Zmeskal. Delta Ferrite Formation and its influence on the Formation of Sigma in a Wrought Heat Resisting Steel. Trans. ASM 1 1949) 11, pp. 1371-1388. 1 J. M. Thomas: Discussion of ref. 3. Trans. ASM (1949) 41, pp. 3 390-1392.

Jan 1, 1957

H. Van F. Furman, Denver, Colo. (communication to the Secretary): There are some statements in Dr. Carpenter's interesting paper which appear to require explanation, if not modification.

Jan 1, 1901

By J. R. Low, A. M. Turkalo

ManY qualitative observations have been made concerning the relationship of the carbide dispersion and the mechanical properties of steel. With reference to the strength and hardness we know that for a given composition a steel having a fine pearlitic structure is stronger than that having a coarse pearlite. The martensitic structure tempered at a relatively low temperature and having finely dispersed carbides gives greater strength than that given by the martensitic structure tempered at a relatively higher temperature and having a coarser

Jan 1, 1959

THE twenty-first birthday of the Rocky Mountain Club will be celebrated on April 11 by the Last Round-up; for, as announced at the annual meet-ing of the American Institute of Mining Engineers in February, the Club and the Institute have voted to con-solidate and formal approval by the court alone re-mains to be secured. The Rocky Mountain Club was organized some years since "to create and maintain good fellowship between the Rocky Mountain members and to further the in-terests of the Rocky Mountain States." From the first, mining men dominated it, as was natural in view of the prominence of mining in the Rocky Mountain region. A series of brilliant annual dinners were held and a site purchased for a clubhouse. A fund was raised to provide a home for the Club. Just as success was as-sured the war came and the members of the Club con-sidered it would be unpatriotic to spend money for such purpose at that time. In a spirit of patriotism the Club funds were devoted to war purposes, especially the Commission for Relief in Belgium and the caring for soldiers going to and returning from the front. So much of the money was used that at the end of the war the project for a clubhouse was out of the question with-out raising a new fund, and since 1923, the Club has been inactive. There is now in its treasury a substan-tial sum. The assets are for the most part the result of contributions made by W. B. Thompson, John Hays Hammond, and Edward H. Clark, all members of the Institute and all of whom wished to see these funds applied in a manner to leave some lasting memorial of the spirit which animated the founders and at the same time perform some useful function in the development of the region in which the Club's interest centered. It was thought that this could best be done through affilia-tion of the Club with the Institute and both organiza-tions have voted for the merger. The Club members not already in the Institute are to have the privilege of a special Rocky Mountain life membership, and the property of the Club is to be used to endow a Rocky Mountain Club fund to be used for purposes in accord with those of both the Institute and the Club and with especial reference to benefiting the Rocky Mountain region.

Jan 4, 1928

By H. C. Weed

THE Inspiration Consolidated Copper Co., located in the Globe-Miami district at Inspiration, Ariz., became a producer of copper in 1915. From 1915 until 1948, 116,278,000 tons of ore were produced from underground workings by the block-caving system of mining. In April 1948, open-pit ore production from portions of the ore body was started and earlier plans for block-caving in these areas were abandoned. The change was due to economic conditions.

Jan 8, 1950

New York L. W. FRANCIS, Chairman, WILLARD S. MORSE, Vice-Chairman. THOMAS T. READ, Secretary, Woolworth Bldg., New York, N. Y. P. A. MOSMAN, Treasurer. LOUIS D. HUNTOON. WILLIAM A. POMEROY. Boston HENRY L. SMYTH, Chairman. ALFRED C. LANE, Vice-Chairman. AUGUSTUS H. EUSTIS, Secretary-Treasurer, 131 State St., Boston, Mass. ROBERT H. RICHARDS, ALBERT SAUVEUR. Columbia FRANK A. ROSS Chairman. RUSH J. WHITE, Vice-Chairman. LYNDON K. ARMSTRONG, Secretary-Treasurer, P. O. Drawer 2154, Spokane, Wash. FREDERIC KEFFER, FRANCIS A. THOMSON.

Jan 3, 1915

By Y. Oinouye, H. Ries

Of the several interesting physical properties of clay which have claimed the attention of investigators in recent years, none is more important than the behavior of the material when heated to temperatures above those of dehydration. Some of the problems to be solved are: 1. The mineralogical changes that take place in firing. 2. The relation between temperature and change in constitution, shrinkage, porosity, etc. 3. The importance of the time factor, as duration of firing, either in reaching a given temperature, or of exposure to a constant temperature. Mineralogical Changes As a result of fusion, reactions take place between the constituents of a clay, which result in a reorganization of the mass, and the formation of new compounds. Of the new minerals developed, sillimanite is the one usually recorded, and has been referred to by a number of observers.' There appears to be a difference of opinion, however, regarding the temperature at which it is formed. Thus Klein2 notes that sillimanite forms only above 1300" C., while Mellor claims that it can develop below 1200" C., the difference in results being conditioned by the time factor. In Klein's experiments the test pieces were fired in 12 hr., while in Mel-lor's, the temperature rose from 800" to 1180" in 24 hr., and occupied the same time in cooling back to 800".

Jan 1, 1918

By Y. Okahara, I. Iwasaki

Chlorination behaviors of pure iron and manganese oxides were investigated by combining a thermogravimetric analysis (TGA) technique with batch-boat roasting followed by leaching. Ferrous and manganous oxides could be chlorinated readily, but, in the absence of a reductant, the higher oxides of both iron and manganese were dificult to chlorinate. Thermogravimetric analysis curves were drawn to illustrate the complexities of the reactions, and the possible mechanisms were discussed. Then three manganif-erous materials from the Cuyuna Range of Minnesota were treated by a process involving the selective chlorination of manganese followed by leaching. The results were interpreted in the light of the chlorination mechanisms observed on the pure iron and manganese oxides. One of the unsolved problems challenging Minnesota's mining industry is the development of an economic process to utilize the manganiferous iron ores of the Cuyuna Range. Although these ores constitute one of the major domestic reserves of manganese (estimated at 432 million tons'), their grade is too low for them to be mined solely for manganese. The nearly exclusive dependence of the U.S. steelmaking industry on foreign manganese ores has stimulated research over the years in treating the low-grade Cuyuna ores. As a result, a number of processes have been proposed.'-' Among these processes is chlorination. Chlorination is the high-temperature conversion of metallic oxides to chlorides by either chlorine or hydrogen chloride gas, or by solid chlorides of sodium, calcium, or magnesium. The metallic chlorides are then recovered by either vaporization or leaching. Although chlorination is an old art, it has become popular in recent years for the recovery of such new metals as titanium, zirconium, and niobium; for the removal of impurities like copper, lead, and zinc from pyrite cinder for ironmaking raw materials;' and for the segregation roasting of coppera and nickel' ores. The chlorination processes proposed for manganifer-ous iron ores have been relatively few (hydrogen chloride chloridization-leaching, hydrogen chloride and calcium chloride chloridization-volatilization,' and chlo-rination-selective condensation6), due presumably to the economics and to the corrosion problems involved. However, the successful application of chlorination processes to other ores will undoubtedly contribute to technological advancements in the chlorination of man-

Jan 1, 1971

By Merlin H. Aylesworth

THE subject assigned to me is peculiarly appropriate to the anniversary of the birth of Abraham Lincoln. If we applied to our present problems the ideals and methods of the Great Emancipator, the future of American institutions would be so definitely assured that there would be little need to discuss the matter. The only inquiries would relate to the pace of progress, not to the possibility of progress. As a nation we have grown more and more to revere the memory of Lincoln, to honor his character, to extol his teachings and to eulogize his concepts of democracy. We rec-

Jan 1, 1940

By David H. Y. Tang

The reinforcement mechanism of suspension effect is analyzed based on beam-column theory. The equations of the maximum bending stress, deflection and transferred bolt load for the bolted roof strata are derived. In the analysis, the bolt load is assumed to be point load and the horizontal stress is uniformly applied to each stratum. The reinforcement mechanism of friction effect is also analyzed. The major function of roof bolting in this case is to create the friction- al resistance by tensioning the roof bolts, thereby the individual thin strata are "welded" into one single thick stratum. Based on the results, equal spacing of roof bolts is used in the suspension effect while for friction effect, the bolts should be spaced based on equal shear force concept. The design nomographs for the proper bolting pattern and bolt tension of mechanical roof bolting systems are presented for practical applications.

Jan 1, 1984

By Y. Nakada, B. Chalmers

The work-hardening behavior of surface layers of aluminum and gold single crystals was investigated by alternately deforming and then removing a thin surface layer by electropolishing or by etching. Aluminum crystals exhibited lower flow stresses after the surface removal; gold crystals did not. Abrasion of surface eliminated easy glide in both gold and aluminum crystals. By alternately deforming and removing the surface layer, it was shown that the abraded crystals work-harden preferentially under the abraded layer. It is suggested that this phenomenon is caused by the difficulty of propagating dislocations through the abraded layer. It has been demonstrated in numerous cases'-3 that the plastic behavior of metals in either single-crystal or polycrystal form is sensitive to the environment and to the condition of the surface; it has also been reported4-6 that single crystals of some metals, when deformed in tension, exhibit more work hardening near the surface than in the interior. A third type of effect that has been attributed to the special part played by the surface in plastic deformation is the influence of the dimensions of the specimen on the various parameters that define its plastic-deformation characteris- tics.?-'' Many of these experiments were made on aluminum, on which an oxide film is always present under available experimental conditions; many of the effects have been attributed to the oxide film, either in terms of its higher elastic moduli, which would cause local stress redistribution, or its higher strength, which would oppose the escape of dislocations at the surface of the metal. On the other hand, it has been suggested II,12 that the mere presence of a surface should be sufficient to produce the observed results. A rigorous examination of this question could, in principle, be carried out by comparing the behavior of aluminum with its oxide film with that of the same material without oxide. This experiment would present great difficulties. The most practical alternative is to compare aluminum with gold, which has no crystalline surface film at room temperature, and to study the effects of various surface treatments on gold. The experiments described in this paper fall into two groups, the objectives of which were to determine 1) whether single crystals of gold shared the property of aluminum that the removal of a surface layer after some plastic deformation reduced the flow stress for further deformation and, since the result of this was negative, 2) whether a surface treatment could be found that caused gold to behave in this way. I) EXPERIMENTS AND RESULTS All the tests described below were carried out on single crystals of about 6 by 6 mm cross section and of sufficient length to provide a gage length of about 10 cm.

Jan 1, 1964

By Desmond Y. M. Lee

Computerized preventive maintenance has been a long sought goal in many industries. People have firmly believed that proper implementation of such a system can result in tremendous saving of money. However, the preventive part has always been left out without realizing it due to the inflexibility of coping with environmental changes. With this in mind, the Iron Ore Company of Canada has developed a computerized system which schedules maintenance jobs preventively.

Jan 1, 1977

By A. Stumpf, Y. Berube

An experimental apparatus for studying the aqueous oxidation of sulfide minerals is presented. The oxidation kinetics for molybdenite in solutions of caustic soda and dissolved oxygen are discussed; results of leaching experiments on chalcopyrite concentrates are given. Preliminary results on the transfer of oxygen into water are also discussed.

Jan 1, 1974

By H. C., Weed

THE Inspiration Consolidated Copper Co., located in the Globe-Miami district at Inspiration, Ariz., became a producer of copper in 1915. From 1915 until 1948, 116,278,000 tons of ore were produced from underground workings by the block-caving system of mining. In April 1948, open-pit ore production from portions of the ore body was started and earlier plans for block-caving in these areas were abandoned. The change was due to economic conditions. Prior to the war years Inspiration's costs of mining by block-caving methods were comparable to, or even below, the costs of some open-pit operations. By the end of the war these conditions were completely changed. Underground costs had risen steadily for labor and supplies. Difficulty was being experienced in finding competent underground men and underground development was almost hopelessly behind schedule. On the other hand, open-pit costs had been sharply reduced through the development of modern earth-moving machinery and plenty of labor was available for surface work.

Jan 1, 1950

By S. Ito, Y. Watanabe

In the long range production planning at the Matsumine mine, a management target is to maintain a desired production rate and to keep fluctuations in copper and zinc grades within given allowable limits. A simulation model was developed to find, on a trial and error basis, how feasible and practical the target may be under certain constraints on the underground mining sequence. A number of simulation runs have been made to obtain the most suitable production rate for the long term. In this paper, an outline of the simulation model is described.

Jan 1, 1976