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By Stanley J. LeFond

Brazil is one of the most outstanding examples of economic development of our time. Its amazing growth record is substantiated by a GNP which has increased at an average rate of 92% for the period 1968-1970 and estimates for 1971 range from 11.7-12.5%. Hence, this growth, coupled with a more relaxed attitude of the Brazilian government towards foreign participation in business opportunities and the remittance of profits out of the country, has caused many exploration companies to reevaluate the potential of Brazil. Despite recent press notices and publicity, Brazil is still not a mining country in the tradition of Canada or Australia. It is still basically an agriculture and manufacturing country.

Jan 11, 1973

By Sydney H. Ball

AMERICAN consumption of industrial diamonds has increased five fold in the past 25 years and today accounts for 15 to 20 percent of the world's sale of rough diamonds. In another decade the value of industrial diamonds sold may well equal or exceed that of gemstones. It is generally understood that industrial diamonds are one of the strategic minerals being stocked by the Government in the present crisis to ensure rapid and efficient armament production. Diamond die making is a trade largely confined to artisans in Switzerland and in certain parts of France. Today, in addition to turning out pilots, we should train expert artisans in diamond die making, for thousands of miles of tremendously small-gauge wire will be needed to make the instruments by which the efficiency and safety of these pilots is assisted.

Jan 1, 1941

By M. C. LAKE

THE industrial development of the United States has been stimulated by the presence of high-grade iron ore in the Lake Superior district. These great deposits have been susceptible to economical extraction and are conveniently located for cheap lake vessel transportation to the great consuming centers. The district furnishes from 80 to 85 per cent of the iron ore annually consumed in the United States, and a full understanding of the available supply of this great commodity is so important that it is well to consider whether or not the industrial supremacy and national independence attained as a result of the abundance of cheap ore are permanent. The enormous deposits of high-grade ore available in the Lake Superior district have been the foundation upon which the vast industrial structure of the steel and allied industries has been built. It is extremely important to the country as a whole, and especially to those States and communities now dependent on Lake Superior ore for their prosperity, that their industries shall retain the particular advantages with which they are now endowed, and that a generous supply of high-grade raw material be available for their consumption at a satisfactory cost. The steel industry is so basic and fundamental that any fluctuation in the cost of its finished products as determined by the supply and cost of the raw materials involved in its manufacture will necessarily affect the business of a wide variety of industries which are dependent on it.

Jan 1, 1926

By E-Tu Zen Sun

Yunnan, a mountainous province in southwestern China, began to assume its place as an important producer of copper toward the end of the Ming dynasty (latter part of the 16th century), and since then has continued, with minor interruptions, to occupy a leading position as one of the few areas in China where relatively significant amounts of this metal can be produced. Among the copper deposits of this province, those of the following three localities have stood out as being the most significant. 1. Tung-ch'uan, in northeastern Yunnan. Here the ores are primarily bornite and chalcocite, with copper content ranging from 2% to 15% the most noteworthy T'ang-tan mine producing ores averaging 12% copper. Estimated total reserve of pure copper in this area is approximately 1,000,000 metric tons.

Jan 7, 1964

By S. H. Ash, J. J. Forbes

Probably the newest thing in mining safety, or safety for mines, is the apparent dissatisfaction on the part of the mineral industries, as represented by both management and labor, and the general public of the Nation, with the safety record of the mining industry. This is reflected by published comments and papers in the technical press;l-9 in labor periodicals,10,11 in popular journals and periodicals,l2, 13 and in the daily press; also by discussions of the Safety Committees sponsored by the National Safety Council,9, 14-15 the American Mining Congress,l.l6 the American Institute of Mining and Metallurgical Engineers,2,4 the Mine Inspectors' Institute of Amerthe Coal Mining Institute of America,5 19 the American Standards Association, and others.20.21 Mining safety is a joint problem of management and the individual workman. Safety is not attained and will not be attained solely by laws, decrees, and commands because, if it could be done in this manner, acceptable mining safety would have been achieved long ago by the individual states in our Nation and by the nations abroad. The best safety performance is found at plants where management provides a safe environment for the workers; where supervision is efficient and super- visors, others concerned with promoting safety, and the individual worker know through training, experience, and personal contact the safe and unsafe practices of their field; and where the trained individual worker has become safety-minded by experience, quiet influence, unconscious suggestion, and personal guidance. Despite what may be said to the contrary, progress has been and is being made in mining safety. This is shown in Fig 1 to 4. It is beyond the scope of this paper to give possible reasons for the valleys and peaks in the fatal-injury rates. Some recent factors that appear to be contributing to the improvement in these rates are briefly discussed. Aside from mining equipment, "what's new in mining safety" for some mines has been in effect or was tried by others long ago. A safety pro- gram is a living thing; as such, it must be vitalized and continuously fed with enthusiasm, constructive action, and improvements. Because safety is concerned with human conduct, it is necessary to practice safety at all times; if not, it is soon forgotten, and accidents occur. Mining-safety Records The large employment and production concerned with anthracite contribute much to the mining-safety records of the mineral industry. Approximately 81,000 persons are. employed in this industry having mines concentrated in an area of 480 square miles in northeastern Pennsylvania. Because of the achievement of the anthracite industry in safety during 1948, the other branches of the mineral industry can profit by a study of what has been done to achieve that record. Where one mineral is produced by other large groups having methods of mining that are similar in many respects to the anthracite-mining methods, an achievement in such a large industry is important. Salient factors concerned with safetye in the anthracite industry are: no radical change has occurred in the mining-safety regulations pertaining to anthracite mines. Because anthracite mining is a branch of the coal-mining industry,

Jan 1, 1950

CONTENTS PAGE BAIN, EDGAR C.-The Nature of Martensite. Discussed by Ancel St. John, Henry S. Rawdon, Jerome Alexander, Howard Scott 1 FEILD, ALEXANDER L.-Effect of Zirconium on Hot-rolling Properties of High-sulfur Steels and the Occurrence of Zirconium Sulfide. Discussed by Beram D. Saklatwalla, Bradley. Stoughton, Andrew M'Cance, George F. Comstock, Alexander L. Feild 12 SAUVEUR, ALBERT and KRIVOBOK, V. N.-Use of Sodium Picrate in Revealing Dendritic Segregation in Iron Alloys. Discussed by George F. Comstock, John H. Hall 17 KINNEY, C. L., JR.-Economic Significance of Metalloids in Basic Pig Iron in Basil Open-hearth Practice. Discussed by V. J. Pazzetti, George B. Waterhouse, C. L. Kinney, Jr 19 NEAD, J. H.-Absorption of Sulfur from Producer Gas in Open-hearth Furnaces.. Discussed by George B. Waterhouse, C. L. Kinney, Jr 26 PRIESTLY, WILLIAM J.-Effect on Steel of Variations in Rate of Cooling in Ingot Molds. Discussed by Emil Gathmann, Paul E. McKinney, George A. Dornin. 27 MONYPENNY, JOHN H. G.-Stainless Steel, with Particular Reference to the Milder Varieties (Stainless Iron). Discussed by P. A. E.-Armstrong, Beram D. Saklatwalla 33 ROYSTER, P. H., and JOSEPH, T. L.-Effect of Coke Combustibility on Stock Descent in Blast Furnaces. Discussed by Ralph H. Sweetser,. Richard Franchot, Sidney Cornell, T. L. Joseph 41 DAVIS, F. W., and BOLE, G. A.-Observations on Requirements of Refractories for Open Hearth. Discussed by C. L. Kinney, Jr., L. F. Reinartz, P. E. McKinney 46

Jan 5, 1924

By J. O. Betterton, W. K. Noyce

I~JTI HE work on the indium-zirconium system is part A of a larger investigation of zirconium-phase diagrams with solute elements, silver, cadmium, indium, tin, and antimony, which is intended to provide information about the metallic valency of zirconium. The system is an ideal example since the sizes of indium and zirconium atoms are nearly the same, and the solute and the solvent occur in the same row of the periodic table. The only solute from Group III B which had previously been added to zirconium was aluminum' and it was of interest to determine whether indium would dissolve appreciably in alpha zirconium and stabilize this phase in the same manner. Experimental Procedure The experimental methods used in the indium-zirconium work are similar to those described earlier for the silver-zirconium system.' Reactor Grade 1 iodide zirconium of 99.95 pct purity* and indium of 99.99 pct purity were arc cast, and then annealed in silica capsules with protective foils of zirconium and molybdenum. Annealing temperatures and times varied from 1 day at 1300°C to 43 days at 550°C. The compositions of the alloys were detcrmined by an individual chemical analysis of the actual metallographic specimens after two or more sides were examined to insure the absence of solute segregation. Calibrated thermocouples were used throughout, and the uncertainty in the temperatures reported, owing to calibration error, furnace control, and measurement of the small temperature gradients near the capsules, is believed to be well within ±2°C. Typical impurities in the alloys were found by a neutron-activation analysis of four different alloys. The results are given in Table I where the ranges of values will be seen to compare favorably with the usual values for iodide zirconium. With respect to oxygen, nitrogen, and carbon the absence of any unusual amount of these elements compared to iodide zirconium was indicated by the alloy hardness values, since hardness is increased sharply by the presence of these elements. The value for 0 pct In, obtained from the alloys by extrapolation, is 58 2 7 VPN which is in the low part3 f the normal range of hardness found in iodide zirconium. Results of the Experiments The zirconium-rich portion of the indium-zirconium phase diagram from the annealing experiments is shown in Fig. 1. Indium was found to

Jan 1, 1959

By Donald L. Katz

FIFTEEN years ago Dr. Manning published a paper in "Petroleum Development and Technology" on '.Fundamental Research Relating to Petroleum." He tabulated for several industries "the proportion of their present success which can be fairly attributed to the application of information and processes obtained by scientific research," giving petroleum a score of 7 compared to 100 for the electrical and coal-tar industries. Today the petroleum industry as a whole and the producing groups both have raised their score beyond the majority and are climbing toward the top. Present practices are being developed both by fundamental research and the application of the research method in field operation.

Jan 1, 1941

By J. D. Cooner

SINCE my working life of 32 yr has been spent in and about the anthracite mines of the Hudson Coal Co., and the previous 4 yr in a college school of mines, I can write best about the safety program of a coal mining company. However, most of the suggestions, statements and practices mentioned herein are applicable to the members of a safety organization and program of almost any industry. It is realized that industrial officials actually interested in real safety work are fully acquainted with the requirements of a practical safety program. Therefore, for such persons there may be nothing new in this paper. The Hudson Coal Co. of Scranton, Pa., employs 7,000 men and produces 5,000,000 tons of anthracite annually at nine collieries scattered for a distance of 40 miles throughout the Lackawanna and Wyoming valleys of northeastern Pennsylvania. For the past 17 yr of the above mentioned 32, I have been engaged in safety work as a safety inspector, assistant mine superintendent, and at present the safety engineer. I have also had the privilege of visiting coal and metal mines in other parts of the United States and Canada. We Americans are the most careless people in the world. If any one doubts this statement why are 100,000 of our people killed accidentally annually? Or why during the almost four years we were engaged in World War II were more of our people killed accidentally at home than were killed in our army, navy, marine corps, coast guard, and other services during the same period? We are careless everywhere in our homes, on the highway, at work and at play. The purpose of this paper is to outline the requisites of a safety department and its program to stop the accidents occurring to employees at work in mines or industrial plants. The first requisite for a safety program is that the management must be convinced of the need and value of a real safety program. By "management" is meant each department head from the president down. Otherwise a good safety department with a good safety program will not succeed because it will not have the proper personnel and equipment to work with, its rules and regulations will not be enforced, and the members of the safety department will be belittled in the eyes of most of the workmen and supervisors. Next, a safety engineer and his inspectors should have worked in the production end of the mines as workmen and also in an official capacity. They are then in a position to have practical and first hand knowledge of the accident hazards of the industry, how to prevent them, and in general the problems of both the workmen and officials. Some men are appointed as safety inspectors when they are physically unable to carry on as mine officials. Such men may know the safety end of the industry and even be safety-conscious, but if they are physically unable to be mine officials they are also physically unable to be safety inspectors, as a safety inspector in our mines must walk from 2 to 4 miles on each daily inspection-and visit each working

Jan 1, 1948

By Francisco Cadena

THE construction of Norris Dam, built by the Tennessee Valley Authority on the Clinch River, a tributary of the Tennessee River, involved the production of coarse and fine aggregate for approximately 1,000,000 cu. yd. of concrete; A hammer-mill plant for the manufacture of sand from quarried rock was indicated as the most economical method of providing this material. The abrasive character of the feed as compared to the average hammer-mill feed made it necessary to control operations rather closely, and this resulted in the accumulation of many data bearing on production and maintenance. This paper will deal only with three specific sets of data, accompanied by such general infor-mation as miry be necessary to explain the conditions under which they were obtained and followed by discussions on the relation of silica content to hammer wear, comparative costs of slugger and stirrup hammers, and comparative costs of tool-steel and n manganese-steel grate bars.

Jan 1, 1937

By I. C. Edwards, W. J. Dengler, D. F. Lillie

By 1959 the milling plant of Bicr oft Uranium Mines Ltd. had been in operation for two years. During this time many changes, both physical and chemical, had been made in an effort to improve plant efficiency. Investigational work had been facilitated greatly by the fact that the Bicroft mill consists to a large extent of two parallel circuits; however, the number of interrelated variables is great, and it is difficult to measure, let alone control, all of them simultaneously. The Bicroft mill staff feels that much progress has been made, but there is much yet to be done and many questions still to be answered. The Addendum outlines noteworthy developments to the fall of 1960. The property of Bicroft Uranium Mines is located in Cardiff Township in the Highlands of Haliburton County, southeastern Ontario, some 140 miles northeast of the city of Toronto and 70 miles due north of Lake Ontario. The ore-bearing dikes are classed as mafic. nonsegregated, syenite and granite pegmatite. Microline, microline perthite, quartz, sodic plagioclase, and pyroxene or biotite are the main constituents with uraninite, uranothorite, fluorite, titanite, cryolite, calcite, pyrite, pyrrhotite, and molybdenite as important accessories. The mill was designed for a nominal capacity of 1000 tpd with all sections except grinding, leaching, and clarification capable of 1500 tons. Feed was entered to one mill unit on Oct. 29, 1956, and to the second parallel line on November 13. The total feed rate was at 1000 tpd on November 15. The first precipitate was produced on November 12. By August 1958 the average entry had been increased to 1410 tpd without the installation of any additional major equipment. The overall recovery has been greater than 93.0 pct on several months, but a recovery of 92.5 pct appears to be most economical. Operating time for eight months in 1958 has been 97.1 pct although all grinding mills were relined during this period. A generalized flowsheet is shown in Fig. 1 and the plant layout in Fig. 2. The ore is crushed in three stages to -3/8-in. and then is wet ground in two stages to approximately 50 pct -200 mesh. The pulp is thickened to 68 pct solids and agitated by air for 33 hr at a pH of 1.9 as maintained by the addition of 93 pct sulfuric acid. Separation of the uranium-bearing pregnant liquor from the residue is accomplished by five-stage countercurrent decantation (CCD), following which the liquor is clarified for removal of fine slimes. The clarified liquor is treated in the ion exchange equipment in which both the upgrading of the solution and the removal of some impurities is accomplished. Addition of magnesia to the high-grade eluate from ion exchange precipitates the uranium as sodium-magnesium diuranate. After being filtered and dried this precipitate is packaged in drums for shipment. The residue from CCD and the barren solution from ion exchange are neutralized by the addition of lime and pumped to the tailings disposal area. CRUSHING All crushing is done on surface in a conventional three-stage unit consisting of a 36x48-in. Birdsboro Buchanan jaw crusher, a 4 1/4-ft standard Symons cone crusher, and a 4-ft Symons shorthead. Both the two primary and the two secondary screens are 4X 8-ft Symons rod decks. Moisture content of the feed ranges from 3 to 4 pct. In the initial installation the primary screens were equipped with 5/16-in. rods at 1 1/4-in. spacing and the secondaries with 5/16-in. rods at 1/2-in. spacing. With this arrangement the average crushing rate was better than 180 tph. To reduce the work required of the grinding circuit as tonnage was increased, several changes were made in the crushing circuit. By September 1957, both secondary screens had been reduced to 3/8-in. spacing, and rod size had been reduced to 3/16-in. to provide increased open area. Average throughput was reduced to 160 tph. Later, 50 pct of one primary screen was decreased to 1/2-in. opening to better balance the load between the two cone crushers. In May 1958,

Jan 1, 1961

By O. B. Bennett

WHEN diamond drilling was introduced in the Rhokana mines in 1939 it was used principally for pillar removal and for completion of the upper portions of shrinkage stopes which were being affected by increasing pressure. This method of drilling long blastholes proved so successful that it was extended gradually to cover stoping, pillar recovery, and hanging cave work. BY 1949 virtually all the ~roduction of Mindola and Nkana was being obtained by this method. At the present time 87,500 ft are drilled each month by the 80 diamond drills in daily operation. Responsibility for control and issue of diamond drilling equipment and crowns, as well as tabulation of all performance figures, was taken over by a sPecially formed Roto drill department, which also investigated the problems encountered with this new method. To assist this department a fully equipped test chamber, Fig. 1, was established underground where performances of various types of machines and equipment could be studied under conditions as nearly uniform as possible. Since the establishment of this department, which was eventually taken over and incorporated into the study department, considerable experimental work has been done on every aspect of the subject. The problems can be classified broadly under four headings: improvement of drilling equipment, crown design, machines, and stoping layouts. One of the major problems with drilling equipment has been to eliminate vibration. Owing to flexing of rods in the hole, severe friction is set up on the back end of the 'Ore barrel and On any high spots in the rods, inducing harmonic vibration in the string of rods and causing the crown to chatter against the face. This not only causes premature crown failure but also reduces penetration speeds and increases wear on the machines and rods used. In the early days, when only holes of EX size were drilled, vibration was largely overcome by periodic greasing of rods and core barrel during each run, but with the change-over to the larger BX hole it became obvious that application of grease by hand was inefficient and time-consuming, and attempts were made to perfect a self-lubricating core barrel. A series of these core barrels was made up and tested and a number of the latest type were used under normal operating conditions, but although footages up to 120 ft were drilled without refilling the overall performance was inconsistent, and the idea was shelved in view of the success of the stabilizer rods referred to later in this paper. At the same time tests were made with barrels 5 ft and later 6 ft long instead of the normal 2 ft. Although a slight improvement was noticed, greasing was still necessary. It was found that rod vibration increased as the core barrel became worn, and in an early test chamber experiment crowns drilled with a worn core barrel averaged 95 ft with a diamond loss of 4.76 carats, whereas the same type of crowns with a new barrel averaged 228 ft with a diamond loss of 3.13 carats. until then all BX drilling had been done with B-sized rods, but during a test on a string of BX-sized rods it was noticed that vibration was negligible. Because of the larger surface area of metal bearing on the sides of the hole, however, the friction and resistance of rods of this size rendered them impracticable on any but the most powerful of the machines, The use of stabilizers spaced evenly along the rods was the next logical step, and for this B couplings, see Fig. 2, were set with three tungsten carbide inserts 1 in. long placed around the periphery equidistantly and at an angle of 45" with a right hand lead. These were placed immediately behind the core barrel and then at 12-ft intervals, as it was found that vibration still occurred when the stabilizers were more than 15 ft apart. The effect of these stabilizers was immediately noticeable; holes were drilled with a minimum of vibration, penetration speeds were improved, and as it was no longer necessary to grease the rods there was a marked decrease in the overall drilling time for each hole. While tests were being made with the stabilizer comeb periodic were taking place with a set of tapered threaded rods, and because there was marked improvement in efficiency it was decided to incorporate the stabilizers and tapered threading in all new rods ordered for Rhokana. The feature of these rods is that only four full turns are required to tighten the coupling as against nine for the present type of B rods. Also, as they are self-centering it is virtually impossible to crossthread them. Each rod has a male 5" tapered Acme thread, Fig, 3, on one end and a female at the other, so that separate couplings are unnecessary, and every fifth rod has an

Jan 1, 1955

By J. WILLIAM WETTER

WHEN the privilege was extended to me to address this meeting I could not help but make a mental review of my own activities and experiences in connection with association work. After having spent about 16 years in the mining engineering field, I entered into the operating branch of coal mining which afforded, about 12 years ago, my first opportunity of attending a meeting of our local Association and sitting in with the "big boys" of the industry. This was quite a thrilling experience because I had heard a great deal about the various operators who belonged to the Association and knew, or at least thought I knew, that a certain group dominated its affairs and that a "clique" was in control of a sizable "roller" which could be "steamed up" at will to flatten out any opposition which might appear upon the horizon or under it, too, for that matter. Now, I was to have the privilege of observing this "clique" at first hand, of seeing a small group making the policies and shaping the destinies of a great industry and planning the activities of an important Association while a large majority of the members would sit by either complacently or otherwise with the full knowledge that the "roller" was in waiting to reduce them to ribbons at the first sign of resistance.

Jan 1, 1930

By Roger L. Beals, George A. Tweedy

I. INTRODUCTION. THE results of the cyanide-operations, given in detail in the following paper, show the progress that is being made at the Minas del Tajo. The old pan-amalgamation process, in operation up to and including 1905, while paying a profit on high-grade ores, was no longer able to treat profitably the ores in sight at that time, hence an alteration in the process was imperative. The success of this alteration is eloquently expressed by the following data Pan- Amalgamation. Cyanidation. 1905. 1907. 1903. Tons treated, . . 51,387 53,983 69,300 Value per ton (U. S. currency),. $10.75 $8.39 $8.28 Extraction, per cent., 65.00 88.50 S7.45 Extraction, per ton. .- $7.00 $7.4.; $7.24 Total cost, per ton treated, 6.50 4.311 4.01 Profit, per ton treated, . . 0.50 3.07 3.23.;

Feb 1, 1910

By J. H. McCormick

This plant, near Marysville, Mont., was planned to treat the ore from the Piegan and Gloster mines, the latter being one of the early and famous producers of the Marysville district. When the mill was closed in 1888, treatment consisted of stamp milling, followed by pans and settlers for pan amalgamation. The extraction was evidently poor, because, a few years later, thousands of tons of tailings were re-treated by the ranchers in the valley below the mill, by the then new cyanide process, and gave a handsome profit. In 1914, the present owners, after laboratory tests and an experimental mill run, decided upon the following treatment: crushing to 40 mesh in cyanide solution, concentration, amalgamation, classification, and cyani-dation of sands by leaching, and of slime by agitation and decantation in charges. The ore averaged about $7 per ton, gold and silver, the ratio of weight being 1 oz. gold to 7.56 oz. silver. The ratio of gold and silver in tailings was 1 oz. Au to 36.6 oz. Ag; the quartz was sharp and sandy, however finely ground, and rather difficult to slime. The mechanical equipment was a No. 5 Symons gyratory crusher; three 10-ft. Lane slow-speed Chilean mills; one Wilfley roughing and one finishing table; one submerged-type Akins classifier; five 26 by 10-ft. fir leaching tanks; one 24 by 7-ft. Dorr thickener; four 14 by 16-ft. Dorr agitators; four 6-compartment double-row zinc-boxes having compartments 18 in. wide, 18 in. deep, and 34 in. long; Johnson zinc lathe; acid and vacuum filter tanks for treating precipitate; roasting furnace; and Case tilting No. 275 crucible furnace for melting precipitate. The mill is driven by electric power supplied by the Montana Power Co. at the following rates, per kw.-hr.: 200 to 300 hp., 0.68 c.; 300 to 500 hp., 0.61 c.; 500 to 750 hp., 0.55 c.; plus $1 per month per installed motor horsepower. The plant as above described was operated from May, 1915, to the end of the year, when an additional Dorr thickener and a 12 by 12-ft. Portland revolving filter were added, increasing the nominal capacity of 100 tons per 24 hr., but not the percentage of extraction. The combined treatment, at a cost of $1.48 per ton, saved 90 per cent. of the gold arid

Jan 1, 1919

By J. J. Jonas, J. L. Uvira

Equipment was constructed which permitted the hot compression of 99.8 pct Armco iron and 2.8 pct Si steel at constant true strain rates of 0.05 to 1 per sec over the temperature range 600" to 1000°C. A maximum true strain of 1.9 could be attained, followed by immediate quenching or by isothermal annealing. True stress-true strain curves were obtained, and the steady-state flout stress, a, strain rate, i, and temperature, T, were found to fit the following expression: The constants A, a, n', and AH were determined for the two ,materials. The activation energies obtained for Arrnco iron and silicon steel are 66 and 80 kcal per mole, respectively, and approximate those for seu- diffusion and for creep. This indicates that hot compression is a diffusion-controlled thermally activated process. THE hot compression of iron and steel is usually carried out in the austenite temperature range,1"7 as this is the one of greatest interest with respect to industrial hot working. However, a disadvantage of testing in the austenite range is that the hot-worked structure is destroyed by the phase transformations taking place during cooling. The present study was therefore carried out in the ferritic temperature range, and the hot-worked substructures were preserved by rapid quenching after deformation. The substructural results will be described in a separate paper, and the present communication is restricted to the strain rate/stress/temperature relationship observed during hot working. The results of hot-compression testing are usually given in the form of true stress/true strain curves, with a different curve for each temperature/strain rate ~ornbination.',~,~ Sometimes simple algebraic equations are fitted to the curves, so that certain extrapolations or interpolations can be performed.1'2'5 These equations are, however, devoid of mechanistic interpretations. The present study was undertaken to show that hot compression can be described by an equation of the type used in creep studies. That is, it will be shown that the temperature dependence of the strain rate in hot working is well-represented by an Arrhenius term, with an activation energy similar to that for creep. Also it will be seen that the stress dependence of the strain rate is similar to that for creep EXPERIMENTAL METHOD AND MATERIALS The investigation was carried out with the following three ferrous materials: 1) Armco iron; 2) Armco iron with 0.26 pct Mn; 3) 2.8 pct Si steel. The first two materials were utilized for investigations performed in the temperature range 600" to 800°C; the last one was used for tests at temperatures from 600" to 1000°C. The materials were of commercial purity,* as shown in Table I. Cylinders of five different sizes were prepared by strain annealing. The resulting mean grain diameter was 3 mm in the 1-in. Armco iron and 2 mm in the other sizes and grades. Different ratios of diameter/height were used to enable the determination of the coefficient of friction. The specimen faces were provided with concentric grooves, which acted as lubricant holders during compression, as recommended by English and ~ackofen' and others.2'9 Powdered glass lubricants were applied to the samples before hot compression to decrease friction and barreling, following the practice of previous investigator~.~~~~~~~~ Different mixtures of glass powder were used for each temperature, after the determination of suitable compositions by experiment.'' Equipment for Hot Compression. Hot-compression tests were carried out on an adapted 150-ton vertical hydraulic extrusion press and also on a modified high-temperature creep machine. The modified extrusion press was used for temperatures up to 800°C. The following items were added to the press: a) a high-temperature furnace with built-in upper and lower platens; and b) a transmission assembly, which permitted the attainment of logarithmically decreasing crosshead speeds. These accessories are described in detail in Ref. 11.

Jan 1, 1969

By T. C. Desollar

THE group of iron-ore mines known as the Red Ore Mines, owned and operated by the Woodward Iron Co., is on Red Mountain approximately ten miles southwest of Birmingham, Ala. At the, present time No. 1 and No. 3 mines are active, No. 2 mines having been abandoned in 1928. Ore from this group of mines was first mined in 1882, and originally came from open cuts along the outcrop, but, when the "soft ore" (weathered hematite) was mined out and the harder ore was encountered, it became necessary to develop the orebody by means of slopes driven in the ore formation. The three mines to date have produced more than 22,000,000 tons, and the two operating mines now have a capacity of over 1,000,000 tons per year.

Jan 1, 1933

By H. DeWitt Smith, W. H. Sirdevan

The mine operated by the United Verde Copper Co. is situated near Jerome, Ariz., on the eastern flank of the Black Hills, at an elevation of approximately 5500 ft. (1676 m.) above sea level. The mine and the town of Jerome are located on a steep hillside, which slopes rapidly to the valley of the Verde River. The smelter town of Clarkdale is situated in the Verde valley 4.1 mi. (6.5 km.) distant in an air line from Jerome, and at an elevation of 3560 ft. The two towns are connected by the standard-gage railroad of the Verde Tunnel & Smelter R. R., a subsidiary of the United Verde Copper Co. This road is 11 mi. long and has a compensated 4 per cent. grade. At Clarkdale, it connects with the Verde Valley branch of the Santa Fe R. R. The narrow-gage (36-in.) line of the United Verde & Pacific Ry. was, until 1919, Jerome's only rail connection with a main trunk line. This road connects with a branch line of the Santa Fe system at Jerome Junction, after traversing 26 mi. of mountainous country. From the time of its location, in 1876, until its purchase by Senator W. A. Clark, of Montana, in 1889, the United Verde mine was worked on a small scale and shipments of high-grade gold-silver ore were made from the surface workings. Until 1894, when the narrow-gage railroad to Jerome Junction was completed, all supplies for the mine and smelter

Jan 1, 1922

By J. Chipman, G. G. Hatch

One of the important functions of the iron blast furnace is the desulphur-ization of pig iron before it enters the steelmaking furnaces. However, the increasing concentrations of sulphur in the metallurgical coke, source of approximately 90 pct of the sulphur present in the blast furnace charge, and demands for higher rates of production within recent years have increased the need for greater desulphurization within the iron blast furnace. Furnace operators are beginning to look for desulphurizing agents other than blast furnace slag to accomplish the desired degree of desulphurization. A considerable amount of work has been done on desulphurization outside the furnace with soda ash, calcium carbide and various synthetic slags. Whether the desulphurization of pig iron is accomplished wholly inside the furnace or partly inside and the remainder outside, will be determined by the economics involved. Regardless of which is the case, it is believed that it is necessary to have a better understanding of the physical chemistry of desulphurization by blast furnace slags. To this end, it is the object of the present investigation to attempt what is believed to be the first equilibrium study of the distribution of sulphur between liquid pig iron and a wide range of blast furnace slag compositions. Review of Literature There is a considerable amount of information in the literature concerning the desulphurizing power of iron blast furnace slags, the solubility of various sulphides in the slags, and the effect on desulphurization of temperature, of elements dissolved in the liquid iron, and of viscosity. However, there is nothing to indicate that the equilibrium distribution of sulphur between liquid iron saturated with carbon and iron blast furnace slags has been studied experimentally. Wentrupl has made probably the most detailed study of the desulphurization of pig iron to date. He considered that there are three distinct aspects involved, namely: 1. Desulphurization within the blast furnace (by lime and manganese). 2. Subsequent desulphurization by manganese. 3. The effect of subsidiary reactions on the desulphurization by manganese. The experimental work carried out by Wentrup was devoted mainly to obtaining a better understanding of how desulphurization by manganese was accomplished in the mixer and the ladle. Particular attention was given to the part played by carbon, silicon, and phosphorus associated with manganese in the iron, and the effect of temperature on desulphurization. The experimental results indicated that desulphurization by manganese is purely a process of crystallization of manganese sulphide. The addition of silicon to iron melts containing 3.5 pct carbon and less than 0.5 pct manganese had no noticeable effect on desulphurization, but with 1-2 pct manganese the silicon additions improved the desulphurization. Additions of phosphorus also resulted in improved desulphurizati011 by manganese, but the effect was not as marked as in the case of silicon. It was also found that desulphurization by manganese was further improved by lowering the temperature. In order to explain desulphurization inside the blast furnace, Wentrup considered the system iron, sulphur, calcium, oxygen, manganese. (silicon). The distribution of sulphur between the metal and slag was represented by the following equation: (SS) _ (S)Fe + (S)Ca + (S)Mn .... [S] = [s] [1] The parentheses and the brackets represent the equilibrium concentrations in weight per cent of the slag and metal constituents, respectively. Since FeS D (FeS) _ (FeS) (S)Fe LfeS - [FeS] [S] [2] (CaO) + S e (FeO) + (S)Ca _ (FeO)(S)Ca. (S)Ca _ (CaO) Kl = (CaO)[S] [S] ~K1(FeO) [3] Mn + S D (S)Mn (S)Mn (S)Mn K' = [MnpT "1ST = *lIMnJ !4) Substitution of Eq 2, 3, and 4 into Eq 1 resulted in if = L- + *> (Sol + K^ (S) [51 Eq 5 was used to calcu1;lte -f^j and [S] at 1480°C for slags containing 30-50 pct lime, 0.1-2.5 pct iron oxide, 0-26 pct silica, 2 pct sulphur and iron analyzing 1.5 pct manganese. The value for LFaB at 1480°C was found to be equal to 4.5, based on the experimental work of Bardenheuer and Geller.2 The results of the calculations are shown in Table 1. Although the slags are hypothetical and do not represent the range of compositions found in ordinary blast furnace practice, the calculations indicate that lime is effective in controlling desulphurization only if the iron oxide and silica contents of the slag are kept low. Schenck3 did not claim K1 to be a true equilibrium constant, but an empirical value which varied with the silica content of the slag.

Jan 1, 1950

By Frederic Brunton

I. INTRODUCTION THE smelting plant of the British Columbia Copper Co. at Greenwood, B. C., now closed because of the decline in the price of copper due to the European war, is of special interest to metallurgists for several reasons. It was successfully smelting in blast furnaces the lowest grade copper ore of all plants in America. In order to do so, it had to run at' very high efficiency, which necessarily required a large tonnage per square foot of hearth area, together with the minimum amount of labor and other costs. The furnaces smelted daily 2,250 tons of ore (6.62 tons per sq. ft. of hearth area), carrying 0.85 per cent. of copper, at a smelting cost of $1.18 per ton. The entire plant required 130 men to operate it and keep up repairs, showing a labor efficiency of about 17.5 tons per man per day. In the present paper, the method of obtaining these results is shown. Most of the information contained in this description I obtained as Assistant Superintendent, during the two years preceding the present shutdown. Other sources of information to which I am indebted are: The British Columbia Copper Co., Ltd., by Alfred W. G. Wilson, in The Copper Smelting Industry of Canada; Greenwood Smelting Works, by J. E. McAllister, Engineering and Mining Journal, vol. xci, pp. 1011 to 1015 (May 20, 1911); and Description of the Copper Smelter of The British Columbia Copper Co., by W. L. Bell, in Transactions of the Canadian Mining Institute, vol. xvi, pp. 151 to 154 (1913).

Jan 7, 1915