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Executive Committee, Board of Directors H D Smith, Chairman, C E Reistle, Jr, Vice-Chairman, T B Counselman, J S Smart, Jr, L F Remartz Finance Committee, Board of Directors A B Kinzel, Chairman, Philip Kraft, P D Wilson Investments Erle V Daveler, '57, Chairman, Henry Krumb, '56, Andrew Fletcher, '58, G F Moulton, ex officio as Treasurer, A B KInzel, ex officio as chairman of the Finance Committee Endowment W W Mein, Jr, Chairman, D H McLaughlin, J V N Dorr, J B Haffner, J R Suman, Henry Krumb, E V Daveler, D C Jackling, Wilfred Sykes, N G Alford, W J Coulter, C E Weed, 0 H Johnson, L F Reinartz, J B Morrow, R McMillan Endowment Fund "X" G F Moulton, Chairman (RIME Treasurer), Erle V Daveler, '58, G I Brigden, '57, Philip Kraft, '56

Jan 1, 1955

By Peter L. Swanson

A microcrack process zone is frequently suggested to accompany macrofractures in rock and play an important role in the resistance to fracture propagation. Attenuation of surface waves propagating through mode I fractures in wedge-loaded double-cantilever beam specimens of Westerly granite has been recorded in an attempt to characterize the structure of the fracture process zone. The ultrasonic measurements do not support the generally accepted model of a macroscopic fracture that incrementally propagates with the accompaniment of a cloud of microcracks. Instead, fractures in Westerly granite appear to form as gradually separating surfaces within a zone having a width of a few millimeters and a length of several tens of millimeters. A fracture process zone of this size would necessitate the use of meter-sized specimens in order for linear elastic fracture mechanics to be applicable.

Jan 1, 1984

By M. E. Nicholson

IN order to understand how alloying elements influence hardenability through their effect on the rate of pearlite nucleation, it is advantageous to use a model to describe the mechanism of pearlite nucleation. The model which currently is most widely accepted has been described, among others, by Mehl et a1.1-3 and by Hultgren.4 Pearlite nucleation involves both the nucleation of ferrite and cementite.4,5 Cementite nucleates first, followed rapidly by the formation of ferrite at the cementite-austenite interface. The conclusion that cementite is the first phase to form during the process of pearlite nucleation is based, in part, on the observation that proeutectoid cementite is continuous with pearlitic cementite and that the orientation relationship between proeutectoid ferrite and austenite is not the same as that between pearlitic: ferrite and austenite.6,7 Recently, Smith" has suggested that the dissimilarity in orientation relations, instead of indicating the pearlite nucleation sequence, may be evidence that pearlite is nucleated in a grain adjacent to the one in which it is growing. Also, Modin9 as shown that ferrite in pearlite may be continuous with proeutectoid ferrite, and he has also shown that proeutectoid cementite is not always continuous with pearlitic cementite. Thus, it appears that the conclusion that cementite always initiates the pearlite nucleation process is open to serious question. The author believes that important evidence on the question of how pearlite is nucleated exists in the rates of pearlite nucleation of different steels. The following is a review and analysis of this evidence. If the nucleation of pearlite is considered as requiring the nucleation of both cementite and ferrite, then the time to nucleate pearlite consists of the time to nucleate the first phase to form, plus the time to nucleate the second phase at the advancing interface of the first. In the absence of a visible proeutectoid constituent, the second phase must be nucleated very soon after the first. If cementite is the first phase to form, the time to nucleate pearlite will be approximately equal to the time to nucleate cementite. Since the nucleation rate of a phase precipitating from solid solution increases with the degree of supersaturation, it would be expected that the rate of pearlite nucleation should increase with increasing carbon content. Digges10 has shown that the reverse is true. He determined the quenching velocity necessary to suppress pearlite formation in plain carbon steels as a function of carbon content. His results showed that pearlite formation could be suppressed with lower quenching velocities as the carbon content of the steel increased, at least up to 1.25 pct C, the highest carbon content he studied. Thus, it would appear that in plain carbon steels, in which pearlite is formed at the nose of the C-curve, the hypothesis that cementite nucleates first does not predict the observed change in nucleation rate. The validity of the current model of pearlite nucleation may be tested also by determining whether or not it predicts the relative influence of alloying elements on the nucleation of ferrite and pearlite. This can be done best by a consideration of the changes in a TTT diagram produced by a change in alloy content. Hultgren4 suggests that the general shape of a TTT diagram, as well as what constituents will form from austenite, can be predicted from the relative nucleation rates of ferrite and cementite. This is illustrated in the schematic diagram for a hypoeutectoid low alloy or plain carbon steel shown in Fig. 1. The C-curves for ferrite nucleation and for cementite nucleation are represented by AA' and CC', respectively, and the start of ferrite formation and pearlite formation are represented by AX and BC respectively. Adopting the current theory, Hultgren suggests that between X and C pearlite forms directly from austenite, since cementite nucleates more rapidly than ferrite in this temperature range. Conversely, at temperatures above Tx, ferrite is the first to nucleate and proeutectoid ferrite is formed. As proeutectoid ferrite grows, austenite becomes enriched in carbon, so that the cementite nucleation rate is increased. As a result, pearlite nucleation above temperature Tx is accelerated, beginning along BX and not along C'X. Temperature T, represents the temperature at which the nucleation rate of ferrite equals that of cementite. By extending this type of reasoning, using the principle that the nucleation rates of ferrite and cementite increase with increasing supersaturation of austenite with respect to these phases, it should be possible to predict the influence of carbon content on the shape of the isothermal transformation diagram. For a slightly higher carbon content than that of Fig. 1, the curve A A' representing the beginning of ferrite formation should be moved to the right, whereas the curve CC' representing the beginning of cementite formation should be moved to the left. For hypoeutectoid plain carbon and low alloy steels, this prediction does not agree with existing data. Instead, as the carbon content is increased, the pearlite curve moves to the right along with the ferrite curve and always appears to join it tangen-tially. This behavior is demonstrated by the TTT-curves of a series of manganese steels" shown in Fig. 2. In this figure, TTT-curves for four alloys containing 0.20, 0.40, 0.60, and 1.20 pct C are superimposed. The curves are identified in the figure legend. The letters F, P, and C are used to indicate the start of ferrite, pearlite, and cementite formation, respectively. In these steels, it appears that the nucleation of ferrite and of pearlite are related processes. As a result of the foregoing evidence, it is proposed that the formation of pearlite be considered as follows: Either ferrite or cementite may nucleate from austenite, then grow until the remaining phase is nucleated at the interface between the growing phase and austenite. (The growth of the first phase to form is assumed to be accompanied by a composition change in the adjoining austenite.) According to this model there are two modes of nucleating pearlite: 1—where cementite initiates the succession

Jan 1, 1955

By T. F. Witherbee

(Read at the Amenia Meeting, October, 1877.) THE subject of an article in the Engineering and Mining Journal for October 13th, 1877, namely, Blast Furnace Treatment of Silicious Iron Ores,, is of great interest to myself, and doubtless to many others who have been troubled with a seemingly unaccountable percentage of silicon in their pig iron. It is to be regretted that the author of the article did not give us complete details of his charges, and thus prevent a possibly fatal error in the very beginning of the discussion of the points raised in his communication. As it now stands, I think we will have to fall back upon the statement that, "every conceivable mixture of fluxes and ores (A and B) has been used." Let us first, in order to simplify the calculations, do with the

Jan 1, 1878

By Y. H. Liu, R. Kiessling

The chromium, iron, and tungsten borides have been treated with ammonia at different temperatures. They are attacked, forming metal nitride and boron nitride, and the results are summarized in the tables. In the tungsten-nitrogen system a new phase has been observed, closely related to the known ß phase. THE present investigations were begun to determine whether any ternary phases exist in the transition metal-boron-nitrogen systems for the metals chromium, iron, and tungsten. Attempts to prepare such phases were made by using the borides of the metals as starting materials and ammonia as the nitriding agent. Although no new ternary phases have been found to exist, the results may be of some interest with regard to the technical use of the borides. General Procedure A steady stream of dry ammonia was passed through a silica reaction tube, the central part of which was kept at the reaction temperature while its ends were water-cooled. Weighed amounts of the borides were placed in a silica or porcelain boat and heated at different temperatures for a period of 10 to 24 hr. The boat was then rapidly removed from the reaction zone to the quenching zone, the water-cooled end of the tube, by means of a simple magnetic device. The nitrogen content of the products was determined by the increase in weight of the specimens, and the phase analysis was carried out by X-ray methods. For this analysis a Guinier-type camera, constructed at this Institute, was used with a bent, ground quartz crystal monochromator. The general reaction, which occurred in all the experiments, may be summarized as: metal boride + nitrogen -* boron nitride + metal nitride For the higher temperatures pure metal was formed instead of metal nitride. It is sometimes difficult to Discussi detect boron nitride among the reaction products by X-ray methods. Prolonged exposures of some specimens showed, however, that the strongest reflections of boron nitride were present. Additional evidence for its presence was given by the increase in weight of the specimens after nitriding. This increase was always greater than that corresponding to nitride formation only and was often in close agreement with the formula given above. Finally, a white powder, which was shown by X-ray methods to be boron nitride, was left if the reaction products after nitriding Fe,B at 448°C and FeB at 768°C were dissolved in diluted sulphuric acid. Ch rom iu m - Boron - N itrogen Five phases have been found to exist in the Cr-B system,' , and all were used as starting materials. Investigations on the Cr-N system have shown the existence of two nitrides with ideal composition Cr,N and CrN.".' * The results are summarized in Table I. All the borides are attacked and decomposed into chromium nitride and boron nitride, and the kind of nitride formed depends only on the temperature and not on the boride used as starting material. The lowest reaction temperature, however, is different for the different borides. Thus the 6 phase begins to react at about 735 "C, the r phase at about 800°, the S phase at about 900°, the 7, phase

Jan 1, 1952

By Charles H. Foreman

IN JUNE 1921, the Sullivan &lining Co., owned jointly by the Bunker Hill and Sullivan Mining & Concentrating Co. and the Hecla Mining Co, started work on the development of the Star Mine. The development work contemplated called for a crosscut from the Hecla workings on the 2000 level to the Star ledge. The length of crosscut necessary to encounter the Star ledge was approximately 8900 ft. from the Hecla shaft. By using workings formerly made by the Hecla Mining Co., only about 8100 ft. of actual crosscutting was necessary. This crosscut has a direction of S 20° W and would have a tendency to crosscut any ledges in the intervening ground.

Jan 1, 1924

Sailing westward from the Society Islands in the fall of 1774, England's noted explorer Captain James Cook discovered New Caledonia-that long, linear island that has played such an important and varied role in the history of nickel. Upon his return to England the following year, Cook's announcement of this uncharted island generated governmental interest, but its distance from the Island Empire, the troubles in the colonies, and the difficulties with France combined to keep English interest indirect and in the background of the then-current events.

Jan 10, 1968

By N. L. ALISON

MUCH has been published on the general subject of metal mine ventilation but, so far as I can discover, few specific data on selection of fan equipment to meet the requirements of a given mine ventilation problem are available. This article is intended to point out some of the more important considerations which influence the selection of such equipment. It will be assumed that the mine operator is able to determine the quantity of air which is necessary in the various parts of his mine to produce the required results and the pressure in inches water gage needed to circulate this quantity of air through the mine. There may be instances in which this assumption is not justified, but the fact remains that, with proper engineering talent, these data can be approximated sufficiently close for practical purposes.

Jan 1, 1930

By A. Eilers

A number of the copper refineries in this country have lately separated some of the rarer metals from the slimes in the refinery tanks. One of these has furnished me the following table of recoveries from given amounts of blister. I publish this to show the proportions, to gold and silver and to each other, in which these rarer metals may be expected to occur in copper from certain localities. GarFIeld, Utah :—The blister copper comes principally from the Bingham porphyry copper mines. Steptoe, Nev. :—All the blister copper is produced from the Nevada Consolidated mines. (Also porphyry deposits.) Omaha, Neb. :—Blister copper comes principally from concentrated copper-lead mattes shipped from the different lead-silver plants of the Rocky Mountain region to the converters at the Omaha lead refinery. Mountain, Cal. :—Ores occur in connection with diorite (?).

Jan 1, 1914

By AIME AIME

JOHN LIVERMORE CHRISTIE belongs to that group of metallurgists who entered the industrial field during World War I and have been responsible for many of the important metallurgical developments since that time. He was born in Montclair, N. J., on Jan. 31, 1894. After graduating from Montclair High School he attended Sheffield Scientific School, Yale University, received his Ph.B. degree in chemistry in 1915 and that same year was employed by the Bridgeport Brass Co. in its laboratory. Among his first duties was the return to Sheffield Scientific School for two years of graduate work in metallography under C. H. Mathewson; receiving his M.S. degree in 1917. Thus we see him becoming one of that group of eminent physical metallurgists who, with Dr. Mathewson's teaching as a foundation, have done outstanding work in metallurgy.

Jan 1, 1945

New York Meets first Wednesday after first Tuesday of each month. Chairman. PERCY E. BARBOUR, Vice-Chairman. A. D. BEERS, Secretary, 55 Wall St., New York, N. Y. C. A. BOHN,.Treasurer. JOHN V. N. DORR, LEWIS W. FRANCIS. Boston Meets first Monday of each winter month. W.. E. C. EUSTIS. Chairman. R. L. AGASSIZ. Vice-Chairman. E. E. BUGBEE, Secretary-Treasurer, Mass. Inst. of Technology, Cambridge, Mass. ALBERT SAUVEUR, H. L. SMYTH. Columbia Holds four sessions during year. Annual meeting n September or October. W. H. LINNEY, Chairman. OSCAR LACHMUND, Vice-Chairman. LYNDON K. ARMSTRONG, Secretary-Treasurer, P. O. Drawer 2154, Spokane, Wash. STANLY A. EASTON. S. SHEDD. Puget Sound Meets second Saturday of each month SIMON H. ASH, Chairman. I. F. LAUCKS, Vice-Chairman. CHARLES SIMENSTAD, Secretary-Treasurer, 425 Lyon Bldg., Seattle, Wash. GLENVILLE A. COLLINS, JOHN N. POTT

Jan 5, 1917

C. Q. PAYNE, New York, N. Y. (written discussion*).-The method adopted by Mr. Lennox is a very interesting test of the practical application of Mr. Gates' crushing-surface diagram to a greet variety of gold and copper ores. His method of dealing with the material below 200-mesh is also a distinct contribution to the subject, although, as he suggests, it seems likely that some microscopic measurement of this material may be advisable before the mesh reciprocals of its group particles can be dealt with as accurately as can those coarser than 200-mesh. In examining the general results shown in Table 3, it is somewhat puzzling to perceive why Calumet &, Hecla jig tails should show a crushing resistance 3 - times greater than that of the ore from the Ray Consolidated copper mine. The latter is, I believe, an altered. Pinal schist

Jan 10, 1918

By Joseph H. Allen

Commercial coke is made to-day in the United States chiefly from the Appalachian, the Illinois and the Colorado coal-fields. The measures of the great Appalachian coal-fields furnish by far the largest proportion, only about 1 per cent. coming from those of Illinois and Colorado. This is not due, however, to a corresponding difference in area. The Illinois field covers about 47,000 square miles in Illinois, Southern Indiana and Western Kentucky. The coal is high in both ash and sulphur, and on this account nearly all the attempts which have been made from time to time to coke it have resulted in failure, so far at least as the requirements of ironmasters are concerned. Nevertheless,. I am able to say from a practical knowledge of this field that the physical structure of the coke is perfect, and

Jan 1, 1893

By C. K. Leith

CERTAIN ideas on iron and steel sanctions to follow originated in a series of conferences held under the joint auspices of the War Department and Brookings Institute in Washington last spring. The views presented may be regarded as those of substantial segments of the steel industry. In view of the fact that steelmaking capacity can be so quickly converted to the production of armament, any effective control must necessarily include the entire steel industry and not solely the parts devoted to the production of implements of war. It must also be exercised all the way from production and shipment of raw materials through their ultimate conversion into finished products and use. Control will be dis- cussed under two main headings: (I) control of raw materials at the source; (2) control of steel capacity within the Axis countries.

Jan 1, 1944

Few people in the industry today are competent to comment on the O.G. system for vessel covers, but with papers as well prepared as Mr. Bradley's we will soon be well informed. I would like to direct these comments to Mr. Klaes of Ford Motor Company. Mr. Klaes' description of their steaming hood agrees with our experience at Weirton. We have been able to stay within design limits and, as a result, have had few problems with our auxiliary equipment. Our main problem, as with Ford, has been thinning of our vessel cover tubes. At Weirton, controlled circulation, high pressure boilers are in use as heat recovery units above the BOP vessels. The boilers are provided with "off cycle' oil firing equipment. A Venturi type wet gas scrubber follows the boiler to complete the vessel draft system.

Jan 1, 1972

By William P. Blake

In a former paper read at the Washington meeting of the Institute, February, 1881,' I presented a general view of the geology and veins of Tombstone as then developed. Considerable additions have been made to our knowledge of the oredeposits since that date, nearly all the mines having been worked down to the general wster-level of the district. This water was a bar to further progress in depth and costly pumps were erected at the Grand Central mine and at the Contention. By the united action of these pumps the water was gradually lowered, not only in these two mines, but in all the important mines of the district. Pending a consolidation of interests, or an equitable distribution of the cost of unwatering, both pumping-plants were destroyed by fire, and the mines were closed

Jan 1, 1904

By L. D. Frink

Those actively interested in mining are fully aware of the ever-increasing difficulty of making conditions such that efficient work can be done in underground openings, especially as higher rock temperatures are encountered in depth. This is also true where an effort is being made to cut down the burden of overhead expense by working headings 24 hr. in a day if blasting is done as often as is possible in that time. That the conditions resulting from both these causes have driven the native-born Americans from the mines and that their places have been taken by less efficient foreigners is a fact that we must all admit. The great war now being fought in Europe and the educational qualification clause written into our immigration law by the last Congress will probably limit very materially the supply of labor, such as we are now using in our mines, and will force upon mine operators the necessity of making this work appeal again to Americans. Metal tubing, with blower or exhaust fans, has long been used in supplying air to dead ends where natural ventilation is impossible, or in driving the smoke from such places, or in doing both, as the need might be. Here in Butte we have now come to use canvas tubing very extensively and find that it has many advantages not possessed by the metal. The use of flexible tubing is not new, but it has not been generally used in mining operations. Recent improvements, however, in the canvas itself and in the jointing of sections and manner of suspension have so increased its usefulness that it promises to add much to the efficiency of mining. There is now on the market a product that is impervious to air, is fireproof, and has a system of jointing which permits it to be put up or taken down in a few seconds. In this article an effort will be made to explain the manner in which canvas tubing is being used in the North Butte company's operations at Butte, Mont. The accompanying photographs will, I hope, help make clear what may be done with this material.

Jan 1, 1918

(Members are, urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who registered at Institute headquarters during the period April 10 to May 10; I. N. Knapp, Ardmore, Pa. E. P. Mathewson, Anaconda, Mont. Herbert B. Cox, New York, N. Y. H. B. Barling, New York, N. Y. A. McLintock, Brooklyn, N. Y. M. M. Thompson, Morsemere, N. J. Heinrich Ries, Ithaca, N. Y. Howland Bancroft, Denver, Colo. R. M. Catlin, Franklin Furnace, N. J. John H. Adams, Birmingham, Ala. Percy E. Barbour, Candor, N. C. Henry D. Boddington, London, England. A. D. R. Galloway, Qruro, Bolivia. William J. Cox, Denver, Colo. M. K. Rodgers, Westgate, Cal. W. J. Morrison, Toronto, Canada. W. J. Richards has been elected President of the Reading. Coal & Iron Co., succeeding the late George F. Baer.

Jan 6, 1914

V. R. GARFIAS,* Palo Alto, Cal. (written discussion?).-Regarding the statement of Mr. Ordoñez, on page 1007, concerning the synclinal curving of sedimentary beds caused by the extrusion of volcanic necks, that "this phenomenon might occur, but it is not fully proved in our fields," I beg to reply that the funnel and anticlinal-ring structure is actually associated with igneous intrusions in the Mexican oil fields, as we were able to ascertain by plotting an underground contour map and making a structural model of the oil-bearing beds of the Ebano field. E. DE GOLFER, New York, N. Y. (written discussion?).-The paper under discussion is not only of interest in connection with its subject but it is a contribution of considerable importance to our knowledge of the possible effect of igneous rocks upon the accumulation of petroleum in the Mexican fields.

Jan 10, 1918

THERE is at least one concrete indication that Soviet Russia's two most important iron ore producing centers are seriously depleted. While keeping in mind Russia's penchant for reverse propaganda, one piece of evidence indicates that Magnitugorsk in the southern Urals and Krivoi Rog in the Ukraine have been mined to a point where lower grade ores are being recovered. An article in Pravda, Soviet newspaper, by I. P. Bardin. a Russian metallurgist, says that ore presently mined must undergo an expensive enriching cycle before it can be used in blast furnaces. Com- pounding Russian metallurgical troubles is the low quality of coking coals. High ash and sulphur content typifies the coal Badin talks about. Coal from the Ukraine, Eastern Siberia, Kazakhstan, and the Far East requires extensive treatment before it can be used, according to the article in Pravda.

Jan 7, 1953