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By F. A. Hill

Coal mining in the State of Washington offers many interesting problems for the mining engineer, due to the varied physical conditions occurring in different fields, and often in the same mine. The different coal seams worked in the same mine commonly require different mining and transportation methods for economical operation. The coal measures have inclinations ranging from 5' to vertical, and in the same mine the dip of the coal may vary from 30' to 50 . In all fields, the seams are extensively faulted, folded, and sheared. The quality of the coal produced ranges from brown lignite to bituminous coking coal, the following being typical analyses: Very little of the coal contains as much as 0.75 per cent. sulfur. The brown lignites occur mostly in Lewis and Thurston Counties, and as a rule are very cheaply mined. This coal has been successfully used in locomotives of the Oregon & Washington Railroad, after equipping them with specially designed fireboxes. The sub-bituminous coals occur in all the coal-mining counties. Their cost of production varies widely, according to the character of the formations, the pitch, and the wall conditions. This makes a fairly good steam coal, but the lump is used mostly for domestic trade, after grading into lump, nut, and pea. The coking coal is used for making coke, and for locomotive and other boiler fuel. It yields a strong metallurgical coke, quite high in ash, though seldom exceeding 18 per cent. ash. Most of it is susceptible to

Jan 1, 1920

Soil Testing for Engineers. By T. W. Lambe. Published by John Wiley & Sons. 165 P. $5.00.-Filling a need for a text for the teaching of soil testing in the laboratory, this book is also of value as a reference for practicing engineers and for personnel in soil laboratories. Following an introductory chapter on general laboratory procedures are chapters devoted to the individual laboratory soil tests which are commonly employed. Apparatus, supplies, recommended procedures, discussion of procedure, calculations results, and numerical examples are provided for each test. Brief derivations of formulas and explanations and discussions of calibration procedures and special techniques are given in the appendix. Mesabi Pioneer. Copyrighted 1951 by the Minnesota Historical Society.- Publication of this book has been made possible by a generous gift to Society from the E. J. Longyear Co. of Minneapolis. This book covers the evolution of the Mesabi Range from a wilderness into the nation's greatest iron producing area. In this book is found the first hand experiences of Edmund J. Longyear who saw the development of the range from its beginnings, and who himself took a notable part in it. In 1890 Edmund J. Longyear sank the first diamond drill hole on the Mesabi. During the next two decades he sank pits and holes- 7133 of them-throughout the length and breadth of the Mesabi Range, exploring for iron ore. He saw roads and railroads built. He watched the range communities--Hibbing, Chisholm, Biwabik, Mountain Iron and the others change from exploration camps to

Jan 11, 1951

By W. A. Oates, J. S. Blakemore, E. O. Hall

AS part of an investigation into the effect of hydrogen on the serrated yielding of Ni-Cu alloys,' it was necessary to determine the solubility of hydrogen in the alloys of interest. With the exception of the work by Fukusima and Mitui2 who investigated the solubility of hydrogen in solid Ni-Cu alloys at 20 wt pct intervals at 1050°, 700°, and 350°C, the information in the literature is limited.3-10 Alloys were prepared from deoxidized Analar Copper and Mond Nickel pellets.' Wire samples were hydrogenated at 7.8 atm in an autoclave consisting of 5 ft of thick-walled Inconel 600 tube with a resistance furnace around the middle portion. The top end, at room temperature, was fitted with a safety valve, a calibrated pressure gage, and a sample inlet, while the bottom end, again at room temperature, was filled with water. After reaching equilibrium samples were quenched by dropping from the high-temperature region of the autoclave into water. They were then quickly transferred to liquid nitrogen where they were stored until analyzed for hydrogen using an Exhalograph.11 The results, which are shown in Fig. 1, represent the mean of two separate determinations on each sample. Because of the lower level of hydrogen at the high copper end of the series, the results here are of poor precision using this method. Fortunately, the results of Himmler9 using the Sieverts technique are available for these copper-rich alloys (>80 at. pct Cu)

Jan 1, 1969

(Under this heading will be published notes sent to the Secretary of the Institute by members or other persons introduced by members.) No. 504.-Member, technical graduate, draft exempt, who has been employed as research chemist in cyanidation and flotation for past 5 years, desires position with large company as metallurgist or assistant mill superintendent. Especially experienced in flotation of gold and silver ores, but am also familiar with flotation of lead-zinc ores. Foreign service not desired. Will be at liberty after Dec. 1, 1918. No. 505.-Member, graduate mining engineer, with 8 years' practical experience, including experience as superintendent. Desires position as engineer, foreman or superintendent of mine. No. 509.-Petroleum geologist and engineer, member, now engaged in consulting work, with five years' experience in Mid-Continent and Eastern fields, desires position with responsible concern either in South or South American countries. No. 510.- Chemical engineer, member, technical graduate, at present officer in Chemical Warfare Service of the United States Army, desires position in the East. Several-years' experience in design, construction, and operation of chemical and metallurgical plants. Minimum salary, $200. Available Jan. 1, 1919. No. 511.-Mining engineer, 32 years old, single, desires position. Speaks Spanish and French. Recently manager of large copper mines. Experience in steam shovel and underground mining. No. 512.-Mining engineer, technical graduate, member, 32 years old, single, 10 years' experience in United States, Mexico and Central America in mining, prospecting, milling, chemical research and business experience. Speaks Spanish. Open for engagement as superintendent or assistant. Can give references as to ability and integrity.

Jan 1, 1919

By I. Iwasaki

In the flotation of iron ores and nonmetallic ores desliming is the key to a successful operation; the technology of flotation of well-deslimed ores has become fairly well established. When finely disseminated ores are ground to liberation, however, conventional desliming of the fully dispersed pulp results in an excessive loss of valuable constituents. Selective flocculation of iron oxides followed by removal of dispersed siliceous slimes is a new development and is one of the most promising approaches to the treatment of finely disseminated, oxidized iron ores, available in vast quantities both here and abroad (1,2,3). To apply selective flocculation to the variety of refractory iron ores or to cope with the fluctuations in an individual ore and the make-up water, the factors governing this technique must be clearly formulated. For the removal of siliceous and clayey slimes from oxidized iron ores by selective flocculation, the optimum conditions are extremely sensitive to the mineralogical characteristics of the ore, the type and the amount of soluble salts in pulp solutions, and the mesh-of-grind. Certain starches appear to function better than others (4, 5). Selection of the proper reagents and their judicious use is important not only for their efficient utilization but also for minimizing the adverse effects they might exert on the flocculation and flotation steps, and the pollution the effluents might cause when discharged, either intentionally or accidentally, into lakes and streams. In the present article some of the major factors that influence the selective flocculation of iron ores are summarized.

Jan 1, 1979

By B. Ladanyi, B. Hoyaux

A first requirement for assessing the safety of a rock slope, either artificial or natural, particularly if the rock behaves in an elastic-brittle manner, is a propw knowledge of the distribution of stresses within the slope and their development with time and advancement of workings. There are a uumber of different methods that can be used, in principle, for obtaining this information, such as (1) stress measurement in situ, (2) photoelasticity,1 (3) analytical methods, and (4) numerical methods. In cases where the stress distribution cannot be obtained by classical analytical methods, as in the one considered herein, either photoelasticity or numerical methods are norrnally used. However, actually, due to the rapid development of high-speed computers, increasing preference is given to the numerical methods. Among the latter, the most successful ones, to date, for determining the stress distribution in slopes have been (1) the finite difference method,2-4 (2) the lumped parameter method,5 and (3) the finite element rnethod.6 However, for determining gravity stresses in a natural rock slope, only the finite difference method has been used until now.7,8 A solution of the same problem by the finite element method will be shown here in which a particular reference is given to the development of tensile fracture zones within the slope. FINITE ELEMENT METHOD The stress analysis using the finite element method originates from an extension of the matrix analysis of structures.9 It consists in decomposing a continuous medium, assumed herein to be homogeneous and isotropic,

Jan 1, 1972

By J. J. Predali, J. M. Cases

J. J. Predali and J. M. Cases (Attachè de Recherche and Charge de Recherche, respectively, Centre de Recherches sur la Valorisation des Minerais, Institut Polytechnique de Nancy, Nancy, France)-The role of CO, in carbonate flotation is one of the parameters of a complex phenomenon: the adsorption of salts of fatty acids onto minerals. The authors therefore must be congratulated for their work. Their experimental results suggest some questions: 1) Recovery with C02, benzoic acid, or HCl, look very similar [(Fig. 1)] to that with the use of air; however, the recovery decreases very slightly (<10%). But in these two kinds of experiments, two parameters are different: the pH which is near 5.8 (with C02) becomes 9.1(without C02) and the concentration of Ca* I x 10-3 mole per 1 (without C02) becomes 1.9 X 10&apos; mole per 1 (without COO. 2) Adsorption experiments (Fig. 2) permit computing the surface coverage 9 which is 7.4% (without C02) and 8% (without CO_.) for an initial concentration of 12 X 10-6 mole per 1 in sodium oleate. It seems doubtful to us that this small variation can produce large increases of the recovery in flotation. 3) It is difficult to correlate adsoption and flotation experiments because they do not seem to have been done with the same size of particles. The concentration needed to obtain 95% recovery (Fig. 1) is about 3.0 X 10_" mole per l, that is, 1.13 X 10-6 mole for about

Jan 1, 1973

By C. A. Heberlein

C. A. HEBERLEIN, New York, N. Y.-The results stated by Rey and Brevers are so startling that they are of great interest, as the concentration of a low percentage of cinnabar by differential flotation yields a high-grade concentrate in the presence of either arsenical or iron pyrite. The authors say: "Cyanide can thus be used to depress arsenopyrite and make a good cinnabar-arsenopyrite separation. A cinnabar-pyrite separation could probably be effected in the same way." Corrosive sublimate at the present price of mercury would be a very expensive reagent but the expense would be justifiable if a high rate of concentration could be obtained with a high extraction. On my request, special tests were made in the Punitaqui mill in Chile along the line suggested by the authors, without any improvement of either grade or extraction. As the recovery of the cinnabar in a complex sulphide of chalcopyrite and pyrite gave unsatisfactory results, I had tests made at the testing laboratory of the American Cyanamid Co. at Stamford, Conn. As these tests turned out to be highly satisfactory, not only at Stamford but later at the mine, they are presented here. [ ] The pulp had a density of 22 and a pH of 7.8. Total time of conditioning was one minute. The reagent added was Texas fuel oil, 0.116lb. of 33.7 Bé. gravity containing 0.9 per cent sulphur. Frother, 0.062 lb. of No. 5 pine oil. Rate of concentration of mercury was 25.7: 11. [ ]

Jan 1, 1941

[ ] Utilizing tendencies for low grade ores in the Sudbury District of Ontario to cave after higher grade ore has been mined, International Nickel Co., of Canada, Ltd., is recovering millions of tons of nickel-copper ore once regarded as submarginal. Inco is working lower grade ore than ever mined before from its underground operations because of the caving method and metallurgical practices. In the caving method, blocks containing as much as 1.5 million tons of ore are undercut. As ore from the undercut block is withdrawn, the block to be mined breaks away and starts to disintegrate as it moves downward. Inco is also using the blasthole method, using explosives to break slices of harder, tougher ore from solid material. Inco has built a new concentrator at one of its most recent shafts for handling the increased tonnages of low grade ore. The concentrator presently has a 10,000-ton per day capacity, and is scheduled to be increased to 12,000 tons. Hoisting from the mine is by push-button control and the ore is milled on the spot. A 7 ½ -mile pipeline carries bulk concentrate to reduction plants at Copper Cliff. Giant crushers, weighing 165 tons each, have been installed underground. Twenty-ton electric locomotives haul ore to the crushers. The expansion program is expected to lift total annual production of nickel in the free world to 375 million pounds annually, an increase of 150 million pounds. Inco is presently mining more than 1 million tons of ore per month from combined surface and underground operations.

Jan 1, 1952

By R. R. Kimpel, L. G. Austin

An equation is derived describing fragment size for single fracture of brittle solids. It contains the equations of earlier workers as special or approximate cases and, in addition, is capable of describing coarse distributions in which a few large particles are produced on fracture. The equation can be fitted well to single fracture experiments where over-breakage is avoided. In 1956 Broadbent and callcottl described a method of analyzing the unit operation of grinding, applicable to homogeneous breakage of brittle materials. In essence, the grinding process was split into two parts: 1) the fractional amount of a given size which is selected for grinding per unit time, 2) the size-weight distribution of the fragments produced by breakage of this certain size (primary breakage distribution function). The theory was formulated using matrix algebra. They attempted an experimental verification of the theory using an assumed primary breakage distribution but the results were not very satisfactory. Austin and Gardner2 showed that this assumed distribution was widely different from experimental values and that it led to the poor agreement of predicted size-weight distributions with experiment found by Broadbent and Callcott. In addition, Austin and Gardner2,3,4 reformulated the original approach in terms of differential equations of grinding and demonstrated that the approach led to a very satisfactory description of the grinding process, providing that the descriptive parameters were measured experimentally. Recent work5 has substantiated these findings and the distribution functions of several materials ground under different conditions in different mills have been determined experimentally. The fraction underweight versus size used by

Jan 1, 1965

WHEN Magma Copper Company in 1952 set about finding $100,000,000 to finance the project of developing and equipping the property of its lusty progeny, the San Manuel Copper Corporation, A. J. McNab, president and guiding genius for both companies (and incidentally a mining engineer by profession), determined that he would avoid the mistake frequently made in such circumstances, of underestimating the cost, and thereby running short of funds before the job was completed. The fear that this might happen was one of the reasons why insurance companies, one potent source of "big" money, were reluctant to finance the enterprise. How, they asked themselves, would Magma, a relatively small company, get additional money in such a contingency? Insurance officials&apos; thumbs were turned down. Conditions Imposed by R.F.C. The upshot was the negotiation by Mr. McNab for San Manuel of a contract with the Reconstruction Finance Corporation, dated July 10, 1952, whereby needed monies in amount up to $94,000,000 would be advanced as a loan, bearing 5 per cent interest. Arrangements were made for the separate financing of the new $10,000,000 town, needed for the project, through the Del E. Webb Construction Company of Phoenix, Arizona, and M.O.W. Homes, Incorporated, of Los Angeles. Thus the $94,000,000 drawing account was believed ample to provide for building the railroad, the mine plant, the concentrator, and the smelter, as well as for the underground development of the mine needed to start production. As a matter of fact, only

Jan 1, 1957

COMPARED with the equipment used in most industrial processes, the open-hearth furnace has a relatively short life. The most important quality of an open-hearth refractory, therefore, is its rate of failure. This discussion of the physics and chemistry of the individual refractory materials will keep upper- most the question "Why, how, and where does it fail?" CAUSES OF FAILURE The principal causes of failure of open-hearth refractories are, in their order of importance: 1.Reaction with iron oxides. 2. Reaction with slag. 3. Flow and failure under load. 4. Melting. 5. Spalling. 6. Mechanical breakage. Reaction with Iron Oxides and Slag. Reaction with iron oxides and slag is by far the most important cause of failure. Liquid iron oxide comes near to being the "universal solvent" sought for by the alchemists. Among the materials commonly used in the open-hearth furnace, magnesia has the greatest resistance to this liquid and fireclay the least. The relations of iron and oxygen at high temperatures are illustrated in Fig 14-18. The liquid iron oxide that forms wherever iron is in contact with air or combustion gases cannot be given a definite formula. The percentage of oxygen at steelmaking temperatures may range from 21 to 28 (iron 79 to 72), depending upon the temperature and the oxygen pressure and also upon whether or not the liquid is in equilibrium with metallic iron. Oxide mixtures exist not only in the solid and liquid phases but also in the vapor phase, for metallic iron and its oxides have

Jan 1, 1951

By Fred Witt, Milton Schwartz

ESTABLISHED methods for obtaining quantitative pole figures for flat sheets1"5 can be extended to apply to thin films on a substrate. The mode of scanning the sample is exactly the same as described in the references? but consideration is given to the fact that the scattered X-ray intensities are due to both the thin film and its substrate with appropriate attenuation factors. The purpose of this paper is to describe a method to obtain the scattered intensities from the film alone for subsequent pole-figure determinations. Fig. 1 shows the four possible general positions of the film (f) and its substrate (s) with respect to the incident X-ray beam (I,). In this paper it will be assumed that the plane of the sample is normal to the plane of the diffractometer. In the diagrams the line jV is the normal to the flat sample and the line P is the trace of the diffracting crystallographic planes in the plane of the diffractometer. The angle of tilt, a, is the positive acute angle measured from the line N to the line P; if this angle is measured clockwise then a is said to be in the positive a region; if this angle is measured counterclockwise then a is said to be in the negative a region. For the reflection cases, the total scattered intensity, at the proper Bragg angle for a particular set of planes, is due to that scattered by the film Vf) and that scattered by the substrate. The beam incident on

Jan 1, 1967

By Bahngrell W. Brown

IN an age when anything short of miraculous can and does happen it is entirely too easy to become labeled as a prophet. After the first wave of hysteria over atomic weapons died down there were crystal gazers enough in that field. The mining fraternity, always anxious to get back to normal anyway, looked, was duly impressed, and passed on to more mundane affairs. After all it was just another big blast in the stopes of life. After we "laymen" had seen the effects at Hiroshima and been granted a peek into the phenomenon of Numbers 4 and 5, we saw, indeed, that it was a tremendous but understandable weapon. Now it appears that we may fall heir to much of the defensive planning of the future. If, as our military planners tell us, it will be necessary to go underground for defense, then we are the true forerunners of a race of troglodytes. The underground belongs to us as to no other profession; the subsurface is our prerogative. Already the big mistakes in planning atomic defense are being made. It is within our ability now to correct them. Surveys are being made of natural caverns to be used as a basis for military planning. This is our first big mistake. Even if the natural caverns, many of which Nature has precariously carved from cherty and brittle limestones, could withstand the seismic force of a proximate blast without major roof failures, there is a more serious argument against the blanket use of natural caverns as a first line of defense. In addi-

Jan 1, 1946

THE third annual Joint Western Mining Convention, held at Los Angeles, Sept. 10 to 13 inclusive, was a notable success both as to attendance and interest. Registration the first day amounted to 201, and the total crept up to 347 before the close. The American Institute of Mining Engineers was well represented, approximately 80% of those registered and most of the speakers being members. This illustrates largely the amount of interlocking membership and the reason for holding at one time and place meetings of the several related organizations. The plan has proved so successful that it is probable that Spokane will extend an invitation for next year that seems likely to be accepted. It is proposed that the convention be timed so as to permit visitors from the East to stop there Oct. 3 to 5, en route to the American Institute of Mining Engineers meeting at San Francisco, Oct. 7 to 9. Simultaneously, it is expected that the Petroleum Division will hold its fall session at Los Angeles, the two streams of travel meeting in San Francisco, just before departure of the party of engineers traveling to Japan to attend the World&apos;s Engineering Congress. The Los Angeles meeting opened Monday morning with a general session under the auspices of the Western Division of the American Mining Congress with Philip Wiseman in the chair. After a series of short responses to the welcome extended, Charles W. Merrill discussed the needs of the western mining industry. A complimentary luncheon to members and delegates followed.

Jan 1, 1928

THE total crude production from the Dutch East Indies, and the British Protectorates of Sarawak and Brunei for 1932 is given in the following table: BARRELS BARRELS (42 GAL.) (42 GAL.) North Sumatra 4,226,935 Ceram 326,207 South Sumatra 13,956,157 Sarawak 2,739,650 Java 3,845,568 Brunei 1,322,725 Dutch Borneo (main island) . 9,406,733 Dutch Borneo (Island of Tara- kan) 6,579,184 Total 42,403,159 Production, which had shown a rapid increase from 1921 to 1929, has since been reduced. Exploitation drilling in the majority of the larger fields was suspended and existing production kept within predetermined limits by beaning. Most of the smaller fields were shut down entirely. The depth of producing levels varies widely in the different fields. Shallow fields with drilling depths to 500 meters (1650 ft.) are still numer-ous as well as those with depths between 500 and 1000 m. (3300 ft.). A few of the newer fields reach greater drilling depths. up to 1600 m. (5250 ft.). The deepest exploration well drilled to date (Djambi field, South Sumatra) reached a depth of 2332 m. (7650 ft.) before abandon-ment in March, 1930. The specific gravities of the various crude oils produced range between 0.65 (86.2° A.P.I.) and 0.95 (17.5° A.P.I.). The lighter crudes have a high gasoline content and fuel oils are derived from the heavier crudes, which usually are rich in paraffin.

Jan 1, 1933

1. Healthy and active Local Section organizations are vital factors in promoting the vigor and growth of the Institute. 2. Activity on the part of Local Sections should be recognized and stimulated by appropriation of funds from the Institute&apos;s treasury; and these appropriations should be as. large as is consistent with the relative needs for other activities. 3. As between different Sections, the amount of such appropriations should be based primarily on the extent of activities as reflected in the number and character of meetings held and the attendance of the members at such meetings. 4. In making a request for funds for any year, the officers of a Local Section should submit a report on the printed form approved by the Directors at their meeting on November 19, 1937. 5. A standing Committee on Local Section Appropriations, consisting of one past Chairman of a Local Section, one member of the Institute&apos;s Executive Committee, and one member of the Finance Committee, shall be appointed by the President and shall pass upon requests for appropriations and authorize payments within bounds of the budget. The committee will be guided by the principles herein outlined, always having in mind the vital importance of healthy, active Sections to the, welfare of the Institute as a whole. 6. According to Article XI, Section 2 of the Bylaws, requests for appropriations shall be signed by the Chairman, Secretary and Treasurer of the Section. 7. Requests for appropriations must be in the hands of the Secretary of the Institute by February 15 of the year for which they are desired.

Jan 1, 1946

By Lawrence Adler

MINE hoist ropes have hitherto been selected by successive approximation, a process both tedious and inexact. The proposed expression is a readily solved synthesis of existing data and the following standard equation:&apos; [ W + Wr + (W + Wr) -a 9 (W + W)f + b] n=T [1] For convenience, a glossary of all terms appears on page 564. Since rope weight (W,) and bending load (B) are functions of unit rope weight (Wv), which in turn is a function of rope strength (T), W, and B can be expressed in terms of T. W, as a Function of T: A study of the curve in Fig. 1, unit rope weight vs strength, yields Eq. 2: W. = -f- [2] Therefore Wr = WvL = T. [3] iv B as a Function of T: From Fig. 2, unit rope weight vs diameter, Eq. 4 is obtained: W, = 1.6d2 [4] B is related2 to d and D, and d has been expressed in terms of W, by Eq. 4, so the curve B vs W, (Fig. 3) gives Eq. 5: 177,000 177,000 This may readily be checked from the expression3 for a 6x19 rope, i.e., d3 B = 288,000D Since d2 = 0.625 W, and N = substituting d into the above expression gives Ea. 6: 180,000 180,000 B T, which will be used. [6] Into Eq. 1 substitute Eq. 3 and Eq. 6, noting that f=0.02: W + T 1.02+=T. [7]

Jan 1, 1958

Geological and Natural History Survey of Wisconsin, The University of Wisconsin, Madison, Wis - E. F Bean, State Geologist. A complete list of publications of this Survey will be sent upon request Only a portion of the Bulletins and Maps fall within the scope of this directory, and most of them are available They are: Bulletin 4, Building and ornamental stones of Wisconsin (1898), $2 50, 6, Preliminary report on the copper-bearing rocks of Douglas County, and parts of Washburn and Bayfield counties (1901), 50 cents, 7, The clays and clay industries of Wisconsin (pt 1) (1901), 50 cents; 14, Report on lead and zinc deposits of Wisconsin (the report is out of print but the 18 maps which accompanied it can still be had) (1906), 20 cents (a series of six maps, supplementary to these (1909), may be had for 6 cents), 15, The clays of Wisconsin and their uses (1906), 50 cents; 16, The geology of north-central Wisconsin (1907), $2, 17, The abandoned shore lines of eastern Wisconsin (1907), 50 cents, 19, Zinc and lead deposits of the Upper Mississippi Valley (1907), 25 cents; 34, The limestone road materials of Wisconsin (1914), 50 cents, 35, Underground and surface water supplies of Wisconsin (1915), $150, 36, The physiography of Wisconsin (new edition now in press) (1916), $125, 41, A study of methods of mine assessments and valuation (1914), 50 cents; 44, Mineral land classification in parts of northwestern Wisconsin (1915), $5, 45, The peat resources of Wisconsin (1915), 50 cents, 46, Mineral

Jan 1, 1933

By David R. Poirier

THE activity of carbon in Fe-C-Cr liquid solutions has been measured by Richardson and Dennis,1 Fuwa and chipman,2 and Goto et aL3 Fuwa and Chipman2 have presented their data along with data of Richardson and Dennis1 and utilized an interaction parameter. However, the interaction parameter is only valid for dilute solutions of carbon, because, as indicated, the same interaction parameter does not apply to more concentrated solutions of carbon (i.e., the effect of chromium on the saturation of graphite in liquid iron). Ohtani4 has attempted to account for the effect of carbon concentration on the interaction parameter; however even his analysis does not apply to the saturation data. Also, the effect of temperature on interaction parameters must be taken into account. Therefore, in any process where the concentration of carbon and/or the temperature changes (such as solidification), the use of an interaction parameter is not adequate to know the activity of carbon. The purpose of this communication is to make use of the existing data on the effect of chromium on the activity of carbon in liquid iron solutions in such a way that the activity can be described as a function of both composition and temperature. The method is an extension of Rist and chipman&apos;s5 analysis for the binary Fe-C solutions. As in Rist and Chipman&apos;s analysis, the activity coefficient is assumed to obey the relation: log y1 = at(l -X1)2 + It [1]

Jan 1, 1969