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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 P. S. Roller

P. S. ROLLER,* College Park, Md.-The author introduces the idea of a grind limit, or lower size limit of the particles formed directly by grinding, and this is stipulated to be 0.70 micron. I wonder where all the particles come from that lie between the resolving power of the microscope and 0.7 micron, which are seen under a microscope in examining a sample of grind? There is also introduced the idea of excess fines; this is all right in itself but the author's quantitative definition seems to be virtually impossible to justify, and, moreover, is obscure. Just why E, the excess fines, should be defined as the distance between an F line and a y line is hard to follow, and just where the distance should be measured does not appear to be stated, as it should be since the F and y lines intersect and the distance between will depend upon where that distance is measured. The basis of the presentation is the relation of log weight against log size that was "discovered" by Schuhmann. While this relation is implied to fit, the only evidence that I can see is a slightly irregular line in Fig. I between 2 per cent and 18 per cent by weight and then a precipitous drop at 18 per cent away from any sort of straight line. Some of the conclusions are rather startling, It is stated that E, the excess fines, remains constant for all the comminution products of any particular material, except that it may decrease for some coarse crusher products. No reason is given for this assertion. One would, on the contrary, expect that excess fines, if such a concept is permissible, would generally vary with different conditions instead of being constant. Again, "as much net energy is required to reduce a ton of quartz to particles of the grind-limit diameter (namely, of course, 0.7 micron) by grinding as is required to melt the quartz." This would require many data to prove, but no proof is given; any consideration would reveal the impossibility of such a result. Still further, ore samples "ground to widely different sizes, and with different circulating loads and different size distributions or product, show the same production of new surface area per revolution of the mill, when this grind limit is used." This statement is confuted by ordinary experience, which teaches that grinding efficiency varies generally with the condition of material. For example, the cushioning effect of fines is widely accepted, while the inefficiency of a ball mill when the feed is too coarse is also well known. R. SCHUHMANN, JR.,* Cambridge, Mass.-Contrary to Mr. Bond's stand, there is a great deal of miscellaneous experimental evidence that comminution does not stop at around 0.7 micron, nor does it cease consuming energy at that point. Comminution is in fact recognized as an important method of producing colloids.5 Mechanical comminution methods were used by von Weimarn6 to produce colloidal dispersions of a variety of solids, including the minerals chalcocite, galena, hematite, stibnite. Utzino7 gives average particle sizes ranging from 0.02 to 0.09 micron for colloids produced by mechanical comminution of several crystal-line solids. Andreasen and Berg8 have ground

Jan 1, 1941

By H. F. Haller

COLUMBIA-SOUTHERN'S Barberton limestone mine, 8 miles southwest of Akron, Ohio, is a million-ton-per-year producer from a depth of over 2200 ft in a district where other underground mining at this depth is unknown. Mining extracts 46 of the top 51 ft from a formation of Devonian limestone discovered by drilling in the 1890's. The same drilling revealed extensive salt deposits below the lime- stone, which led to the location of the chemical plant at Barberton as a division of the Pittsburgh Plate Glass Co. in 1899. Soda ash was the principal product of the plant, and as production increased the demand for limestone increased. Columbia's first attempt to secure a reliable all-weather source of stone was the development of a quarry at Zanesville, Ohio, in 1919. Zanesville production eliminated some of the stock- piling required by the use of Michigan stone, avail- able only during the lake shipping season. Stone from some Zanesville horizons, however, was found to be more suitable for cement production than for soda ash, and rail transportation remained an important factor. As demand continued to increase, plans were made to develop the Barberton deposit.

Jan 12, 1954

What has happened to the basic coal industry during the past year? Has it been a better year for coal than 1961? What striking new developments have occurred in mining, preparation and utilization? Are there positive signs that production will go up? What has happened in the utility market, the metallurgical market and the export market? Is the controversial question of coal transportation nearer to a solution? What progress has research made for coal during the year? The answer to these and many other important questions are offered in the following review of the Coal Industry-1962.

Jan 2, 1963

By R. P. Smith

IN 1937 the employees of the Hollinger Consolidated Gold Mines Ltd., at Timmins, Ont., Canada, approached organized medicine for a plan to provide themselves and their families with a complete medical service including hospitalization. This approach was made because of two conditions: (1) the necessity for some organization whereby contributions could be made in instalments to offset the sudden and large expense connected with illness for which the average employee is not prepared, and (2) the need for a more cohesive quality of service to replace a contract practice then in vogue, which did not take care of the employee's family or dependents. In different parts of the United States and Canada similar plans were in force, not only for employed groups but for numbers of people in circumscribed areas. In Europe different countries had adopted various forms of health insurance plans. It then was no surprise that these employees as a group should ask for some similar plan. With the cooperation of the management, a plan was instituted. The plan has one object only-the provision of medical services, including the accessory services such as hospitalization, X-rays, nursing, and necessary drugs and medicines. It is not concerned with cash benefits, sickness and accident payments, or any form of monetary return as the result of illness, but is simply an organization to provide medical services and pay for them from a central fund. It is a nonprofit organization and the only shareholders are the employees and their families who contribute and who in turn receive services. The Hollinger plan is limited to the employees of the Hollinger mine, who live in Timmins and the immediate vicinity. At first, the membership was voluntary. In the third year, it was made a condition of employment, with the proviso that at the end of any Association financial year an employee may withdraw if he wishes to do so. After withdrawal, he cannot again become a member until the end of the next Association year, and then only by the payment of the back dues. This step was taken to ensure continuity, and to prevent employees from withdrawing when well and reentering when faced with impending illness or operations. The employee himself is subject to medical examination on application for employment, and if accepted is subject to further examination by a specialist in chest diseases under the Workmen's Compensation Board of Ontario. Thus it is possible to exclude those who have heart disease, tuberculosis, or other disabling conditions when first employed. Wives and families of employees are not subject to medical examination but other dependents of an employee-mother, father, or other relative-who are declared by the employee to be wholly dependent upon him must be examined. The employee

Jan 1, 1944

By Arthur S. Dwight

From the latest and best literature on lead-smelting, little can be learned concerning the present state of the art of mechanical feeding in the United States. H. O. Hofman, in his Metallurgy of Lead (5th ed., 1899), briefly describes the main features of the system in use at Pueblo, Colo., and later (p. 235) says " the only successful mechanical feeding, as far as the writer is aware, is that found at the works of the Pueblo Smelting and Refining Co." H. F. Collins, in his Metallurgy of Lead and Silver (London, 1899), covers American practice pretty thoroughly; but as to mechanical charging, he says: "The German plan of taking off the gases by means of a small iron pipe suspended in the center, and the plan of charging by means of cup and cone, as in iron blast-furnaces, have both been tried, but have not found favor, chiefly on account of the difficulty of obtaining free access to the furnace-shaft for barring, etc., with such devices."' . H. W. Hixon, in his Notes on Lead and Copper Smelting (3d ed., New York, 1900), gives a description and drawing of the Hixon feeding device, as originally installed at East Helena. Evidence that this system of feeding has passed its experimental stage, and deserves more serious consideration than it has heretofore received, is furnished by two large plants—the Pueblo and the East Helena—of the American Smelting and Refining Co., where mechanical feeding has been in continuous and successful operation for a considerable period; one new plant now erecting at Salt Lake City, Utah, and one old one belonging to the same company, the El Paso works, now being rebuilt after a disastrous fire, in both of which mechanical feeding is to be a prominent feature ; one new plant of an independent concern at Torreon, Mexico, which will adopt mechanical feeding; and a number of other smaller plants, among

Jan 1, 1902

By Kent R. Van Horn, W. P. Sykes

Since Honda and Murakamil in 1918 proposed their constitutional diagram of the carbon-free iron-tungsten system, considerable effort has been expended by several investigators in attempts to define more positively the structural features of the alloys. The existence of an intermediate phase corresponding to the formula Fe3W2 (68.7 per cent W) was proposed from evidence of a purely metallographic nature by one of the present authors2 in 1926. Since that time the identity of this phase has been confirmed by Arnfelt3 and by Takeda,4 both of whom employed X-ray methods as well as the microscope and the chemical analysis of isolated microconstituents. According to Arnfelt, Fe3W2, as crystallized from the iron-rich melts at a temperature above 1450° C., contains by analysis 68.7 per cent W. The lattice of this phase is characterized by trigonal symmetry. Arnfelt, moreover, proposed a second intermediate phase formed at some temperature between 1450" and 1000" C. by a peritectoid reaction involving Fe3W2 and the iron-rich solid solution. A melt containing 25 per cent W was cooled to 1000" C. and heated for 100 hr. The precipitated tungsten-rich constituent was separated and found by analysis to contain 62.6 per cent W. This composition agrees closely with that represented by the formula Fe2W (62.2 per cent W). Diffraction patterns from the concentrated precipitate showed a hexagonal unit cell. Takeda confirmed the data of Arnfelt regarding Fe3W2 but was unable to detect Arnfelt's second intermediate phase. While Takeda failed to describe in detail the treatments employed, he stated that in alloys containing 40 per cent W which were quenched after heating at various temperatures between 1200" and 1450" C. no evidence of the second phase (Fe2W) was observed 'either in the microstructure or in the diffraction patterns of isolated residues. He therefore considered the existence of this low-temperature hexagonal compound as disproved.

Jan 1, 1933

By E. W. Greene, J. B. Duke

This paper deals with the application of froth flotation techniques to the beneficiation of kaolin clay and phosphate slimes, two very fine particle sized materials. The kaolin problem involves the removal of a small amount of a contaminating mineral (anatase), while the phosphate problem involves the concentration and recovery of a much larger percentage of apatite. Due to these differences, and also different response to flotation, the two problems are discussed in separate parts of the article. An idea of what is meant by "Ultrafine Minerals Or Slimes" as used in the title can be had by an examination of Fig. 1. Particle size distributions are presented for a crude kaolin clay, a coarse fraction and a fine fraction. The crude kaolin as mined was blunged with water, degritted through a 325-mesh Tyler screen, and dispersed with sodium silicate. The dispersed crude was then centrifuged in the laboratory into the coarse and fine fractions shown in the figure. The distribution curves were obtained by the well known sedimentation technique of Casa-grande1 using a long arm centrifuge to obtain equiva- lent spherical diameters down to 0.2 p on the finer fraction. Fig. 1 shows the coarse fraction kaolin to be 50% finer than 3 p, while the crude kaolin is 509 f'lner than 1.4 p, and the fine fraction 50% finer than 0.46~. For comparison 53 p on the horizontal scale would represent Stokesian diameters which would just pass a 325-mesh Tyler screen, taking into consideration the Andreasen sieve correction factor of 1.22 times the screen opening. 2 Another helpful comparison is the surface areas, which in square meters per gram, are 0.044 for 53 p particles, 0.77 for 3p, 1.65 for 1.4 p and 5.0 for 0.46 p particles. Fig. 2 is an electron micrograph of a similar fine fraction kaolin showing the hexagonal plate-like particle shapes.

Jan 1, 1962

By D. N. Witman

ONE of the special uses to which the electric furnace has been put recently is the melting of an alloy of nickel and cast iron for the production of electrical-resistance grids. The metal sections of these grids, Fig. 1, are quite uniform for each pattern, but there is, among the various patterns, a variety of thicknesses. The cross sections vary from 1/2 by 3/16 in. to as small as 1/8 by 1/8 in. The electrical resistance f a perfect casting lies within 10 per cent. above or below the fixed listed resistance for each pattern. Good molding is essential to success in the making of these grids, for with absolutely correct metal, a variation of 0.01 in. in width and thickness of section on some of the patterns may mean as much as 12 or 14 per cent. variation in resistance. The service for which these castings are intended demands that the metal, even in the smallest castings, be very soft, showing an open, gray, highly graphitic structure in order that they may be resistant to shock, and stand up well under rough usage. The metal used for this purpose is a gray iron alloyed with 4 to 5 per cent. of nickel, which element, when the composition of the alloy is correct, imparts toughness and pliability to the metal and helps to overcome the tendency of metal to run white and become brittle because of the rapid cooling action of the sand mold. When cold, these castings can be twisted into various shapes, taking a permanent set without breaking. The alloy has approximately double the electrical resistance of ordinary cast iron. The metal specification is as follows: PER CENT. Silicon 2.40 to 2.60 Sulfur Under 0.05 Phosphorus Under 0.08 Manganese Under 0.40 Total carbon 3.60 to 4.00 Nickel 4.00 to 5.00 Copper 0.50 to 0.70

Jan 8, 1921

By Orville R. Lyons

DISCUSSION Judson S. Hubbard (The Humphreys Investment Co., Denver)—In this very interesting paper several brief references are made to the Humphreys spiral, a device used for cleaning fine coal. In Table I, Plants 76 and 77, data are given on spiral performance treating Raton and Trinidad coal. The fine coal, as fed to the spiral in these instances, is actually a table middling, hence the more easily treated material was previously removed and a large number of particles were present which were difficult to clean. Mr. W. M. Bertholf of the Colorado Fuel and Iron Co. presented a paper in February, 1946, Cleaning Table Middlings from a Coal Washery with the Humphreys Spiral Concentrator, from which I quote: "In considering the results of our tests it should be noted that the feed was our table middling, and that any real separation is a 'moral victory' as there is little material that could properly be called coal and practically no heavy rock, the consequences being that previous attempts to clean the middling have not at all been successful." Referring again to Table I, Plants 72, 73, 74, and 75, these data were obtained by Yancey and Geer and others and presented at the February 1950 Meeting, AIME, in a paper entitled Laboratory Performance Tests of the Humphreys Spiral as a Cleaner of Fine Coal. Results shown for those tests involve all particles from 8 mesh through the colloids, which admittedly is not an ideal situation for spiral feed if much refuse is contained in the —80 mesh or —100 mesh size range. As an illustration of the effect of treating too broad a size range, let us consider Plant No. 75, Kentucky No. 9 seam. Spiral feed was 8 mesh x 0. Now had this been 8x100 mesh the percentage of misplaced material would have been 8.0 pct instead of the reported 15.26 pct. Similar comparisons can be made on the other data presented with respect to the spiral. Other types of equipment show a similar trend in that whenever too fine a size is treated in a given unit process the percentage of misplaced material increases. Since the spiral is working near the finer end of the size range, it will sometimes be advantageous to treat the entire range of —8 mesh material rather than to deslime and make a fair showing on, say, the +80 or + I00 mesh. Desliming is subsequently done in any case in the dewatering or thickening operation. Results obtained by spiraling any given coal depend on factors too numerous and complex to discuss here, but there are strong indications that proper preparation of feed to the spiral can improve results obtained on some of the raw coals tested. This is clearly pointed out at the end of the aforementioned paper by Yancey and Geer. "The spiral is an extremely simple device which involves no moving parts and is constructed almost entirely of unmachined castings. Since it is such an uncomplicated mechanism, operation is simple and virtually foolproof. These characteristics, which go far toward insuring low cost operation, are attractive attributes in any coal cleaning unit." Certain equipment used in conjunction with the spiral has resulted in a decrease in the percentage of misplaced material, notably in actual practice the launder screen which is used to remove objectionable high ash fines from a spiral-washed coal product. Private correspondence with the U. S. Bureau of Mines has intimated that an additional yield of coal is possible by flotation of the spiral middling. Possible future improvements and developments may result from other methods now under consideration. Finally, some compromise must be made between the best metallurgical performance and the best practical or economical results. Mr. Lyons emphasizes in his summary this objective of overall economy in selection of equipment. G. B. Walker (American Cyanamid Co., Stamford, Conn.)—I had the pleasure of reviewing the draft of this paper and my curiosity was aroused by the data given for Tromp plants, in that all of the examples shown appeared to be 2-product separations, whereas all the Tromp plants with which I am familiar have been 3-product units. The data given for plants No. 101 and 102 appear to be taken from Tromp's brochure on his process and represent the results obtained at the Dominale plant in Holland which was operated for many years by Mr. Tromp. The plant, which was designed to treat 58 tons per hr, was sampled while treating 35 tons per hr of 3Y4x-in. coal. Example 101 appears to conform to what would result if the middling product were calculated into the refuse product, while Example 102 represents the calculation of the middling into the coal product. It is believed that Examples 103 and 104 represent the operation of the Willem-Sophie Mine in Holland recalculated on the same basis. In checking the English examples given by numbers 14, 15, 16, and 17, the same procedure seems to have been followed. These results have, apparently, been taken from an article in Colliery Engineering in August 1941, describing the initial operation of the Williamthorpe Colliery of the Hardwick Colliery Co. Two vessels are employed in this plant, one to treat soft coal and one to treat hard coal. Example No. 14 presents the results that could be obtained from the soft coal bath if the middling were calculated into the refuse, and Example 15 the results when the middling is calculated into the coal. Examples 16 and 17 represent the same expedient in the case of the hard coal bath. Of interest to this discussion is the fact that during the past year the Simon-Carves Engineering Co. in England has installed in the Williamthorpe plant their new "Sim-Car" medium cleaning system which is based on magnetic extraction and control and which is licensed under the Heavy-Media Separation Processes patents by the American Zinc, Lead and Smelting Co. This system has been described in the December 1951, issue of Colliery Engineering. It is reported that since the Williamthorpe Colliery was changed from the Tromp system of medium cleaning to the Magneto-Motive method of medium control the opera-

Jan 1, 1953

By Orville R. Lyons

DISCUSSION Judson S. Hubbard (The Humphreys Investment Co., Denver)—In this very interesting paper several brief references are made to the Humphreys spiral, a device used for cleaning fine coal. In Table I, Plants 76 and 77, data are given on spiral performance treating Raton and Trinidad coal. The fine coal, as fed to the spiral in these instances, is actually a table middling, hence the more easily treated material was previously removed and a large number of particles were present which were difficult to clean. Mr. W. M. Bertholf of the Colorado Fuel and Iron Co. presented a paper in February, 1946, Cleaning Table Middlings from a Coal Washery with the Humphreys Spiral Concentrator, from which I quote: "In considering the results of our tests it should be noted that the feed was our table middling, and that any real separation is a 'moral victory' as there is little material that could properly be called coal and practically no heavy rock, the consequences being that previous attempts to clean the middling have not at all been successful." Referring again to Table I, Plants 72, 73, 74, and 75, these data were obtained by Yancey and Geer and others and presented at the February 1950 Meeting, AIME, in a paper entitled Laboratory Performance Tests of the Humphreys Spiral as a Cleaner of Fine Coal. Results shown for those tests involve all particles from 8 mesh through the colloids, which admittedly is not an ideal situation for spiral feed if much refuse is contained in the —80 mesh or —100 mesh size range. As an illustration of the effect of treating too broad a size range, let us consider Plant No. 75, Kentucky No. 9 seam. Spiral feed was 8 mesh x 0. Now had this been 8x100 mesh the percentage of misplaced material would have been 8.0 pct instead of the reported 15.26 pct. Similar comparisons can be made on the other data presented with respect to the spiral. Other types of equipment show a similar trend in that whenever too fine a size is treated in a given unit process the percentage of misplaced material increases. Since the spiral is working near the finer end of the size range, it will sometimes be advantageous to treat the entire range of —8 mesh material rather than to deslime and make a fair showing on, say, the +80 or + I00 mesh. Desliming is subsequently done in any case in the dewatering or thickening operation. Results obtained by spiraling any given coal depend on factors too numerous and complex to discuss here, but there are strong indications that proper preparation of feed to the spiral can improve results obtained on some of the raw coals tested. This is clearly pointed out at the end of the aforementioned paper by Yancey and Geer. "The spiral is an extremely simple device which involves no moving parts and is constructed almost entirely of unmachined castings. Since it is such an uncomplicated mechanism, operation is simple and virtually foolproof. These characteristics, which go far toward insuring low cost operation, are attractive attributes in any coal cleaning unit." Certain equipment used in conjunction with the spiral has resulted in a decrease in the percentage of misplaced material, notably in actual practice the launder screen which is used to remove objectionable high ash fines from a spiral-washed coal product. Private correspondence with the U. S. Bureau of Mines has intimated that an additional yield of coal is possible by flotation of the spiral middling. Possible future improvements and developments may result from other methods now under consideration. Finally, some compromise must be made between the best metallurgical performance and the best practical or economical results. Mr. Lyons emphasizes in his summary this objective of overall economy in selection of equipment. G. B. Walker (American Cyanamid Co., Stamford, Conn.)—I had the pleasure of reviewing the draft of this paper and my curiosity was aroused by the data given for Tromp plants, in that all of the examples shown appeared to be 2-product separations, whereas all the Tromp plants with which I am familiar have been 3-product units. The data given for plants No. 101 and 102 appear to be taken from Tromp's brochure on his process and represent the results obtained at the Dominale plant in Holland which was operated for many years by Mr. Tromp. The plant, which was designed to treat 58 tons per hr, was sampled while treating 35 tons per hr of 3Y4x-in. coal. Example 101 appears to conform to what would result if the middling product were calculated into the refuse product, while Example 102 represents the calculation of the middling into the coal product. It is believed that Examples 103 and 104 represent the operation of the Willem-Sophie Mine in Holland recalculated on the same basis. In checking the English examples given by numbers 14, 15, 16, and 17, the same procedure seems to have been followed. These results have, apparently, been taken from an article in Colliery Engineering in August 1941, describing the initial operation of the Williamthorpe Colliery of the Hardwick Colliery Co. Two vessels are employed in this plant, one to treat soft coal and one to treat hard coal. Example No. 14 presents the results that could be obtained from the soft coal bath if the middling were calculated into the refuse, and Example 15 the results when the middling is calculated into the coal. Examples 16 and 17 represent the same expedient in the case of the hard coal bath. Of interest to this discussion is the fact that during the past year the Simon-Carves Engineering Co. in England has installed in the Williamthorpe plant their new "Sim-Car" medium cleaning system which is based on magnetic extraction and control and which is licensed under the Heavy-Media Separation Processes patents by the American Zinc, Lead and Smelting Co. This system has been described in the December 1951, issue of Colliery Engineering. It is reported that since the Williamthorpe Colliery was changed from the Tromp system of medium cleaning to the Magneto-Motive method of medium control the opera-

Jan 1, 1953

By L. A. Cowan

IF the elements of personality be those characteristics in which humans differ, and if this definition be applied to the purchasing department for the Climax operations in Colorado, it must he concluded that this department has no distinguishing traits that would give it a departmental personality different from that possessed by the similar department of any progressive mining enterprise. Or, one may go further by stating that the rudimentary functions of any purchasing practice employed principally in the acquisition of maintenance, repair, and operating supplies are much alike, whether or not the industry involved be mining or milling. However, in the fact that the principal purchases of a mining company are materials for maintenance and repair and consumable operating supplies lies that essential characteristic which differentiates mining and milling purchasing functions from those of the manufacturer, the fabricator, or the ordinary processor.

Jan 1, 1946

By J. L. Wyatt

The electrical resistance of titanium as a function of purity and temperature was measured from —325" to 2800°F. Two points of inflection in the data plots were found, and an increase in resistance with increase in temperature above the transformation was observed. IN 1948 Greiner and Ellis' reported on the thermal and electrical properties of titanium, including a study of the effect of temperature on the electrical resistance. The materials used in the research were obtained from the United States Bureau of Mines, where powder metallurgy techniques were being employed for consolidation purposes. These authors found a decreasing resistance with increasing temperature above 1625°F, and concluded that the latter temperature represented the point of transformation from hexagonal close-packed to body-centered cubic structure on heating. They reported a specific resistivity value of 55x10-6 ohm-cm, and showed that dp/dt was positive, decreasing with increasing temperature above ambient. In one of his early texts Hume-Rothery2 mentioned that certain metals, including titanium, exhibited minima in plots of resistance vs temperature. He indicated that this occurred at 212°F. Reporting many years ago on the effect of temperature on the electrical resistance of zirconium, de Boer and Fast³ showed that phase transformation in this sister metal occurred over a range of temperatures, the extent varying with its purity. Graphs of resistance vs temperature, showing transformation effects over a range of several hundred degrees, were presented for relatively impure metal. In the latter case the resistance decreased with increasing temperature throughout the region of partial phase transformation, thereafter increasing as predicted for normal metals by modern theories of the solid state. Since the quality of metal used in previous studies was substandard compared with iodide-type titanium, and in view of the fact that there seemed to be some rather unusual observations in the reported literature, it was decided to undertake a more extensive study of the thermal effects using high purity titanium, and to include temperature ranges beyond those which had been studied in order to ascertain whether or not the characteristics of zirconium would be duplicated. Experimental Materials Materials used in this investigation included commercial quality titanium (Ti-75A produced by the Titanium Metals Corp. of America) in the form of ¼ in. diam rods, and high purity iodide titanium (produced by the Foote Mineral Co.) in the form of crystal bar of irregular size. The latter was cold-swaged into rod form and machined to the desired size. Lead wires to all specimens consisted of 18 gage Ti-75A. Chemical analyses of the stock materials are given in Table I. Experimental Procedures Specimens 2½ to 3 in. in length were prepared with diameters nominally 0.15 to 0.20 in. Two holes,

Jan 1, 1954

By R. M. Brown, W. J. Murphy, B. M. Kapadia

An investigatiott was conducted to study the influence of nitrogen, titanium, and zirconium on the boron llardenabilzty effect in a low-carbon constructiona2 alloy steel. The experimental steels investigated exhibited a significant variation in hardenability, the variation being dependent on the interactions of boron, titanium, and zirconium with the nitrogen. Only the boron not combined with nitrogen was effective in increasing hardenability. Titanium, and with lesser effectiveness zirconium, combined with available nitrogen, thereby protecting the boron. The hardenabil-ity effect mas related to an empirical expression for the "effective" boron content, P, deduced from experimental evidence of these interactions. The hardenabzlity effect reached a maximum at about 0.001 wt pct 0, and decreased somewhat as P increased further. The physical understanding of this relationship is discussed. FOR many years boron has been added to steels to obtain high hardenability. Although a great deal of research has been conducted on boron-treated steels, certain aspects of the boron hardenability effect have not been fully understood. For instance, the magnitude of the hardenability effect has been observed to vary markedly, depending on the steelmaking technique, even when the amount of boron in the steel was essentially constant. Furthermore, the optimum amount of this element to be added has not been definitely established. A better understanding of the boron hardenability effect is essential because too small an addition of boron is likely to be ineffective, while an excessive amount can cause brittleness'' and hot shortness. The findings of earlier investigations have shown that the hardenability effect cannot be consistently related to the amount of boron added or retained in the steel. Grossmann observed that in a 0.60 pct C steel the hardenability increased to a maximum with mold additions up to about 0.0025 pct B and then decreased with larger additions. Other investigators5 likewise reported a maximum in the hardenability at about 0.003 pct B. Crafts and Lamont, however, found that in commercial open-hearth heats of medium-carbon steel the hardenability increased linearly with boron up to 0.001 pct and remained essentially unchanged with larger percentages up to 0.006 pct. Other investigators7,' also observed a rather constant hardenability effect in the range about 0.0005 to 0.0035 pct B. These observations and other evidence suggest that the effectiveness of boron in increasing hardenability probably depends, in addition to the amount, on the form of boron retained in the steel, this form being influenced by the presence of other elements. Both oxygen and nitrogen apparently exert the strongest influence on the hardenability behavior, since, at the temperature of liquid steel, boron readily combines with these elements, thereby losing its effectiveness as most experimental evidence seems to indicate. For consistent recovery of the boron effective in increasing hardenability, it is necessary that the oxygen and nitrogen in the steel be either reduced to extremely small amounts by the steelmaking practice or neutralized by combination with other elements before the addition of boron. The importance of achieving adequate deoxidation prior to the addition of boron in order to realize the full hardenability effect of boron has been sufficiently emphasized by earlier investigators. Digges and Reinhart' and others have investigated the role of nitrogen and have shown that nitrogen also interacts with boron and reduces or nullifies altogether its effect on hardenability. Moreover, their work also demonstrated that the addition of strong nitride formers such as titanium and zirconium reduce the deleterious effect of nitrogen on boron hardenability by combining with nitrogen to form stable nitrides. Another element which has a pronounced influence on the boron hardenability effect is carbon. It has been shown7'10 that the hardenability effect of boron diminishes with increasing carbon content, and becomes almost negligible at the eutectoid composition. This observation is useful in comparing the potential increase in hardenability from boron of steels with different carbon contents, but is not relevant to a study of the effects of normal steelmaking variables. The amounts of oxygen and nitrogen in steel vary with the steel composition and steelmaking practice employed. Most commercia1 low-alloy steels are fully deoxidized by the addition of silicon and aluminum, or other strong deoxidizers, which adequately protect the boron from oxidation. In addition, one or more of the elements such as titanium or zirconium are usually added, either separately or in combination with boron, in the form of complex ferroalloys, to protect boron from combination with nitrogen in the steel. However, the actual amount and type of addition employed for a given processing requirement are usually selected by trial and error, and have a rather limited range of applicability. As a result, substantial variations in the hardenability of boron-treated steels are often observed in practice, particularly when the nitrogen content of the steel is a significant processing variable. These variations might therefore be reasonably attributed to the interactions between boron, nitrogen, and titanium or zirconium present in the

Jan 1, 1969

By Charles R. Holmes

MORE than 70 igneous pipes and dikes are known to occur in Cambrian sediments throughout an approximately circular area of about 75 sq miles in southwestern Ste. Genevieve County and southeastern St. Francois County, Mo., across the southern portion of the Farmington anticline, which is outlined in fig. 1. From evidence obtained from fossil fragments taken from some of the intrusive, and from the similarity in composition of the more basic intrusives to those of known age in surrounding states, these pipes and dikes are believed to be at least post-Devonian and probably Cretaceous in age. As first postulated by Rust, these intrusives are believed to represent explosion tubes, or diatremes, punched through great thicknesses of solid rock by gaseous pressure. The particular intrusive studied is located about 1 mile north of the small town of Avon at an elevation of 880 ft in the EM SES NE% of sec. 2, T. 35N, R. 7E. Outcrop is through the Bonneterre dolomite in two separated exposures. The larger outcrop extends east and west for about 50 ft along a tributary in a small ravine (fig. 2). The smaller exposure occurs as a few scattered patches over an area 20 ft square about 100 ft to the north. The area between the exposures is covered, but scattered patches of the Bonneterre dolomite outcrop throughout the area surrounding the diatreme. Where exposed, contact relations show the surrounding dolomite to be shattered and metamor- phosed to a fine-grained rock for a distance of 15 to 20 ft from the intrusive. The igneous rock occurs as a dark greenish-gray porphyry near the center of the diatreme and as a fine-grained, greenish-gray material containing lapilli and metamorphosed fragments of dolomite near the contact with the country rock. The most abundant original mineral of the porphyritic rock is olivine now largely serpentinized as the result of extensive hydrothermal alteration at time of emplacement. The most common constituent of the fine-grained rock, which occurs near the border of the intrusive, is calcite. Mica is a common constituent of both types of rock, occurring as tufts or

Jan 1, 1950

By R. J. Evans

THE Combined Metals Reduction Co.'s plant is at Bauer, Utah. It was built primarily to treat ore from the Combined Metals mine at Pioche, Nevada. Shortly after its completion, the company acquired the old Honerine mine, and ores from this mine, as well as custom ores from widely scattered districts, are now being treated at the Bauer plant. PIOCHE ORE The Pioche ore, which comprises about 50 per cent. of the mill feed, occurs as a replacement of an impure thin-bedded limestone. The lime beddings are separated by thin layers of micaceous shale containing appreciable quantities of sericite and graphite. The ore is an exceptionally fine-grained, dense mixture of minerals and gangue, assaying approximately 0.03 oz. gold, 7.2 oz. silver, 7 per cent. lead, 15 per cent. zinc, 16 per cent. iron, 29 per cent. insoluble and 1.5 per cent. lime. Of the total lead 7 per cent. is in the form of sulfate and carbonate. Approximately 10 per cent. of the ore consists of chert nodules impregnated with barren pyrite; the nodules average 0.8 mm. in size, and are extremely hard, compared with the other constituents of the ore. Microscopic examination of Pioche ore ground to 80 per cent. minus 150 mesh shows pyrite, sphalerite and galena still attached. EARLY ATTEMPTS AT ORE DRESSING Metallurgists, both professional and those working for private companies, have been more or less familiar with the Pioche ore since 1913; in fact, a total of 35 commercial and plant laboratories experimented with the ore between 1913 and 1921. The work during this period was decidedly negative, it being seemingly impossible to effect a satisfactory separation of the valuable minerals into marketable products. In 1913, it was recognized that fine grinding-that is, about minus 200 mesh-was required to liberate the minerals from one another, and from the gangue, but such fine grinding was not considered practicable at this time.

Jan 1, 1928

By B. J. Harlan

THE trying times experienced by the steel industry during the past four years have emphasized the necessity of producing pig iron at the lowest possible cost. The trend in both design and operation of blast furnaces has been toward this end rather than securing maximum production from a unit or group of units. In the following discussion the trend in design of stacks and auxiliary equipment will be taken up before operation is considered. Although few furnaces have been constructed in the past few years, the trend is definitely toward larger furnaces with a hearth diameter of 24 or 25 ft. Such a furnace is very flexible, being able to produce efficiently any desired daily tonnage between 500 and 1000 or more. The detail of the design of furnace stacks, with the exception of the top, has changed little in recent years.

Jan 1, 1934

By S. W. Poole, J. A. Rosa

THE object of this investigation was to determine the distribution of chemical elements within a large, killed alloy-steel ingot, by sulphur printing and quantitative chemical analysis. With regard to segregation in steel ingots, the factors of melting practice, pouring temperatures, mold design, etc., and the mechanics of solidification and its attendant functions, have been the subject of intensive study over a period of years by many investigators. Notable among these is the Sub-Committee of the No. 5 Committee of the British Iron and Steel Institute. For an exposition 0f the many problems awaiting the researcher on the heterogeneity of steel ingots, the methods of attacking these problems, together with some of the answers, the reader is referred to the nine reports and numerous papers of that committee and its membership. STEELMAKING DATA Melt.-The heat was made in a 70-ton direct arc-type basic electric furnace. Furnace charge consisted of nickel-chromium-molybdenum steel, most of it in the form of heavy mill scrap. All of the scrap was charged cold. The standard double-slag method was employed, the heat being finished under a strong carbide slag. Aluminum was used as the deoxidizing agent. Tapping temperature, as observed with an optical pyrometer, was 3000°F. Detail of Mold and Ingot Size.-Details of the ingot mold and the ingot itself are given in Fig. I. Teeming.-Teeming temperature of the subject ingot as observed with an optical pyrometer was 2830°F. The ingot was top-poured directly through a 1 ½ in. nozzle and required 7 min., 44 sec. to fill up to the hot top. An additional 2 min., 30 sec. were required to fill the hot top. The ingot was stripped hot and charged with the remainder of the heat into an annealing furnace. There it was given the standard annealing cycle used for these ingots. Subsequent heat-treatments are described elsewhere in this paper. SECTIONING AND PREPARATION FOR SULPHUR PRINTING Because of previous favorable experience in sectioning ingots up to 21 ½ in. square with an oxyacetylene torch, it was decided to use this method to section the subject ingot. The ingot was preheated to 900°F. for 12 hr. It was then placed on a steel bed in a horizontal position so that the longitudinal axis was level and parallel to the track of the motor-driven torch carrier. Two cuts were made, one 2 in. above the longitudinal axis and the other 2 in. below. The time required to make each cut was approximately 75 min. The cutting operation is shown in Figs. z and 3. The 4-in. thick slab was mmediately charged into a furnace standing at 1200°F.

Jan 1, 1944

In the January Bulletin a list was published of Societies' publications, magazines, etc., which were duplicates and were discarded at the time of-the consolidation of the libraries of the three Founder Societies. A second list published herewith includes text books which are duplicates and which will be disposed of about April 1, 1916, by the Board of Directors of the Institute through the, Library Committee.. If, meanwhile, members desire to secure some of these books, they are asked to communicate at once with the Secretary as. this is an unusual opportunity to secure books at an extremely low price. Airy, George Biddell.-Magnetism, London, 1870, Bd. Alberti, Friedrich von.-Halurgische geologic. Erster Band. Zweiter Band. Stuttgart, 1852, Bd. American Iron and Steel Association.-Ann. Rep. of the Sec'y. Statistics of American and, Foreign Iron Trades, 1877. Phila., 1877, Bd. Same, for year 1878. Phila., 1879, Bd. American. Telephone and Telegraph Co.-Ann. Rep. of Directors to Stockholders, 1911. N. Y., 1912, paper. Armagnat, H.-Induction Coils. Trans. by Otis Allen Kenyon, N. Y., 1908, Bd. Armstrong Cork Co. Insulation Dept. Nonpareil Corkboard Insulation. Pittsburgh, 1909, Bd. Associazione fra gli Industriali Metallurgici Italian.-The Metallurgic industry of Italy. Description of some of the principal works. Milan, 1911, Bd.

Jan 2, 1916

By J. H. Swisher

HIGH-temperature anneals in wet hydrogen are widely used in research as a technique for decarburiz-ing Fe-C alloys. This technique is also used commercially in processing low-carbon steels for magnetic applications. The results of some calculations to be presented show that for temperatures up to 1100°C there is a critical temperature for maximizing the decarburization rate of alloys containing about 0.1 pct C. The low-temperature portion of the iron side of the Fe-C phase diagram1 is reproduced in Fig. 1. Preliminary calculations show that the critical temperature is between 727" and 905°C. In this range, the alloy contains two phases during heat treatment, ferrite and austenite. Decarburization therefore occurs by a process termed "diffusion accompanied by a phase change".' For intermediate stages of decarburization, the carbon concentration profile in a flat plate is shown in Fig. 2. The carbon content increases linearly from zero at the surface to a value, cB , at the two-phase boundary. cB is known from the phase diagram, see Fig. 1. At the interface where x = 5, the carbon content increases to ci, the initial concentration in the alloy. smith3 has derived an equation which describes the rate of movement of the boundary. With a rearrange-

Jan 1, 1969