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By ERJIINICI FERRARIS

1. HISTORICAL REVIEW AND INTRODUCTION. THE development of the mining industry in Sardinia dates from the application of the minim law of 1859, which, following the example of the French mining law of 1810, declared prospecting to be free, and suppressed the liens which had previously attached the mine to surface ownership. The first ore-dressing plants were installed by German engineers upon the classic models of the Harz and of Freiberg; but in 1880 Sardinia commenced to open a new path in that industry, utilizing the refuse from the mining of rich, selected minerals, of poor deposits, and of mixed ores. The first experiments were attempts to adapt the existing apparatus to local conditions, but progress was rapid, as was demonstrated already in 1887 by the calamine-dressing-mill of Monteponi, which exhibited a large plant designed in accordance with the experience gained, and constructed entirely in the machine-shops of the country, after new models and designs.1 This example was followed two years later by the Société Malfidano, with a large plant of the same sort, and with the reconstruction of the old-fashioned-dressing-mill, built in 1880 by the Austro-Belgian Company. In 1900, almost all the mines of Sardinia had adopted the new designs, and the island contained 32 concentrating-works, employing 2,000 h.p. and 1,924 workmen. Since that time, there have been added a large dressing-mill for blende at Gennamari, and two for calamine, at San Giovanni and at Masua, while the establishments at other mines have been enlarged and perfected. For the treatment of intimately mixed ores, a large establishment has been built upon the new

Jan 5, 1908

By W. D. Robertson, J. -P. Briant, M. Gell

The distribulion of dislocatiorls genevnted during the propagalion of hydrogen-induced cracks in Fe-Si cryslcrls was studied as a funclion of temperature f-110o lo 243°C) and silicorz conlenl (3.1 and 4.2 pct). It zoas found that the clislocntiotl densily and the size of the plctslic zone increased with increasing tempevalnre and decreasing silicon conlent. Furtheruvzove, there was a correlcrtion in the dislocalion patterns formed around cracks that propagated at different tempevattrt-es in cvyslals of diffevent silicon contents such that a 1 pcl itlcverise in silicon content was equivalent to a lemperaluore redziclion of approximately 120°C. The experimenlal YeSnllS were compaved with the results of an elastic-plastic wodel that relates the size of the pluslic .zone to the cvack length, internal pressure, and yield stress. it was found that the clzunges in the dislocctlion cryrays with lemperature and combosition can be e-kplaincd by the lemperatrnre and composilion dependence of the yield stress. An wmtsual feature of this study was the observation of low -temperature noncrystrrllogruphic cracks. PLASTIC relaxation can occur at the edge of a moving crack by the operation of pre-existing dislocation sources or by the creation of new sources in a region of perfect 1attice.l'2 The amount of relaxation in a given crystal depends on the crack velocity and the temperature, and can determine whether a crack propagates in a brittle or a ductile manner.1-3 Tetelman and Robertson4 observed microcracks m Fe-3 pct Si single crystals that formed on (100) planes by the precipitation of hydrogen gas during electrolytic charging at 23°C. The plastic deformation accompanying crack propagation was observed in the form of dislocation etch pits and an extensive analysis has been made of the size, shape, and crystallography of the dislocation arrays5-7 This paper describes the effect of temperature on the plastic deformation generated around hydrogen-induced cracks in Fe-3.1 pct Si and Fe-4.2 pct Si single crystals. The observations are compared with the results of an elastic-plastic model for yielding around a crack containing an internal pressure. 1) EXPERIMENTAL PROCEDURES The composition of the materials used in this study are given in Table I. Single crystals of alloy A and the 4.2 pct Si alloy were grown by the strain-anneal method; crystals of alloy B and the 5.1 pct Si alloy were cut from an ingot grown from the liquid. he ~ingle-cr~stal metallographic specimens had a Cross section of 0.100 by 0.050 in. with a length of at least 3/8 in. Specimens were annealed for 3 hr at

Jan 1, 1968

By Thomas V. Falkie

These are exciting times for the coal mining community. Although the industry is in the middle of a healthy boom, there are strong forces tending to counteract or at least temper the rate of growth. There are many pushing and pulling factors of interest to mining people, and a few salient ones will be mentioned here. Primarily because of a tremendous demand for energy, a demand that can't be met by other fuels, the coal industry is in boomsville. Another contributing factor to this situation is the increased overseas demand for metallurgical coal. These demands are being counteracted by a lack of people, the lead-time required to develop new capacity and wildcat strikes, among other things.

Jan 1, 1971

By M. J. Ginsberg, N. A. Gokcen

THE preliminary study of electrochemical desul-furization performed by Ohtani and Gokcen1 left a number of points concerning the process to be investigated. Two of these were i) the determination of the effect of greater current and voltage on the desulfurizing Flower of acid slags (% CaO/% SiO2- 1) and ii) the possibility of the loss of silica in slag by the reactions 2C (in metal) + SiO2 (slag) = Si (in metal) + 2CO(g) and C + SiO2 (in slag) = SiO(g) + cO(g) proceeding to a point at which the composition of the slag was sufficiently altered toward the basic side so a1.s to noticeably affect the rate of de-sulfurization. The apparatus and the procedure used in the present investigation were the same as those used by Ohtani and Gokcen, except the control circuit was connected to 120 v dc instead of 24 v dc and thereby allowed greater freedom in choosing the values of both current and voltage. The graphite crucible containing the melt and serving as the cathode was 3-in. high, and was of 1 1/2-in. ID with a graphite bar of 3/8-in. diam and 8-in. length threaded into the bottom for electrical connection. This was placed into a magnesja outer crucible with a hole in the bottom and alumina insulation was packed between the two crucibles. A charge consisting of 180 g of

Jan 1, 1962

By William B. Plank

NEVER before have so many men chosen the mineral technology field for their college training. In the college year 1936-'37, 7190 such students were enrolled in the 53 schools of the United States. My last study of the mineral technology schools of the United States and Canada was made for the year -1934-'35, and the current study, as the previous one was made for the A.I.M.E. under the auspices of the Division of Mineral Industry Education. Altogether, four studies of enrollment have been made. The first three were for successive college years beginning with 1932-'33. This present one covers a two-year period, for the purpose of these studies may he served satisfactorily if they are made biannually. The data on the schools were collected in the same way as for former studies, 'namely, by questionnaire, dated in this case Nov. 18, 1936. The figures reported are therefore comparable with those of former cars.

Jan 1, 1937

Some Things We Don't Know about the Creep of Metals. By H. W. Gillett (T.P. 1087) Reduction of Iron Ores under Pressure by Hydrogen. By Michael Tenenbaum and T. L. Joseph (T.P. loll, with discussion) Induction Furnaces for Rotating Liquid Crucibles. By E. P. Barrett, W. F. Hol- bRook and C. E. Wood (T.P. 986, with discussion) Mechanism of Solidification and Segregation in a Low-carbon Rimming-steel Ingot,. By Anson Hayes and John Chipman (T.P. 988, with discussion) Solidification of Rimming-steel Ingots. By A. HultGRen and G. PhRagmen. (Contribution 112) Dendritic Structure of Some Alloy Steels. By Daniel .I. Martin and James L. Martin (T.P. 1066, with discussion) Occlusion and Evolution of Hydrogen by Pure Iron. By George A. Moore and Donald P. Smith (T.P. 1065, with discussion) Structure of Iron after Con~pression. Hy Charles S. Barrett (T.P. 977, with discussion) Structure of Iron after Drawing, Swaging, and Elongating in Tension. Ry Charles S. Barrett and L. H. LevensoN (T.P. 1038, with discussion) Magnetic Torque Studies of the Texture of Cold-rolled and of Recrystallized Iron-silicon Alloys. By Leo P. TaraSovJ(T.P. 1012, with discussion) Influence of Atmosphere and Pressure on Structure of Iron-carbon-silicon Alloys. By Alfred Boyles (T.P. 1046) Kinetics of the Decomposition of Austenite at Constant Temperature. By J. H. Austin and R. L. Rickett (T.P. 964, with discussion) Reaction Kinctics in Processes of Nucleation and Growth. By William A. Johnson and Robert F. Mehl (T.P. 1089, with discussion) Phase Changes in 3.5 Per Cent Nickel Steel in the Acl Region. By I. N. Bavarine (T.P. 1031, with discussion) Chromium in Structural Steel. By Walter Crafts (T.P. 1055) Surface Allotropic Transformation in Stainless Steel Induced by Polishing. By J. T. BuHwell and J. WUlff (T.P. 1032, with discussion) Nature of :Passivity in Stainless Steels and Other Alloys, I and 11. Ry H. H. Uhlig and John WUlff (T.P. 1050, with discussion) Thermal Expansion of Nickel-iron Alloys (Nickel from 30 to 70 Per Cent). Ry J. M. Lohr and Charles H. Hopkins (T.P. 987, with discussion) Low-temperature Transformation in Iron-nickel-cobalt Alloys. By L. L. Wy~Ian (T.P. 1013, with discussion) Fracture of Steels at Elevated Temperatures after Prolonged Loading. By R. H. Thielemann and E. R. Parker (T.P. 1034, with discussion)

Jan 1, 1939

Some Things We Don't Know about the Creep of Metals. By H. W. Gillett (T.P. 1087) Reduction of Iron Ores under Pressure by Hydrogen. By Michael Tenenbaum and T. L. Joseph (T.P. loll, with discussion) Induction Furnaces for Rotating Liquid Crucibles. By E. P. Barrett, W. F. Hol- bRook and C. E. Wood (T.P. 986, with discussion) Mechanism of Solidification and Segregation in a Low-carbon Rimming-steel Ingot,. By Anson Hayes and John Chipman (T.P. 988, with discussion) Solidification of Rimming-steel Ingots. By A. HultGRen and G. PhRagmen. (Contribution 112) Dendritic Structure of Some Alloy Steels. By Daniel .I. Martin and James L. Martin (T.P. 1066, with discussion) Occlusion and Evolution of Hydrogen by Pure Iron. By George A. Moore and Donald P. Smith (T.P. 1065, with discussion) Structure of Iron after Con~pression. Hy Charles S. Barrett (T.P. 977, with discussion) Structure of Iron after Drawing, Swaging, and Elongating in Tension. Ry Charles S. Barrett and L. H. LevensoN (T.P. 1038, with discussion) Magnetic Torque Studies of the Texture of Cold-rolled and of Recrystallized Iron-silicon Alloys. By Leo P. TaraSovJ(T.P. 1012, with discussion) Influence of Atmosphere and Pressure on Structure of Iron-carbon-silicon Alloys. By Alfred Boyles (T.P. 1046) Kinetics of the Decomposition of Austenite at Constant Temperature. By J. H. Austin and R. L. Rickett (T.P. 964, with discussion) Reaction Kinctics in Processes of Nucleation and Growth. By William A. Johnson and Robert F. Mehl (T.P. 1089, with discussion) Phase Changes in 3.5 Per Cent Nickel Steel in the Acl Region. By I. N. Bavarine (T.P. 1031, with discussion) Chromium in Structural Steel. By Walter Crafts (T.P. 1055) Surface Allotropic Transformation in Stainless Steel Induced by Polishing. By J. T. BuHwell and J. WUlff (T.P. 1032, with discussion) Nature of :Passivity in Stainless Steels and Other Alloys, I and 11. Ry H. H. Uhlig and John WUlff (T.P. 1050, with discussion) Thermal Expansion of Nickel-iron Alloys (Nickel from 30 to 70 Per Cent). Ry J. M. Lohr and Charles H. Hopkins (T.P. 987, with discussion) Low-temperature Transformation in Iron-nickel-cobalt Alloys. By L. L. Wy~Ian (T.P. 1013, with discussion) Fracture of Steels at Elevated Temperatures after Prolonged Loading. By R. H. Thielemann and E. R. Parker (T.P. 1034, with discussion)

Jan 1, 1939

THE Johnson award for 1926 was given to T. L. Joseph for his experimental work on blast-furnace operation. When the Bureau of Mines undertook its experimental blast-furnace investigation in 1919, a number of operators and metallurgists were doubtful as to the practicability of small-scale tests. Several pre-vious attempts, outside the Bureau, to operate small furnaces had been unsuccessful. However, pig iron was produced in three and four-ton furnaces during the first half of the nineteenth century. The operation of a small furnace did not therefore seem an impossible task. This point of view, together with a realization of the importance of problems connected with the pro-duction of pig iron, prompted the Bureau to undertake this work. Such problems as the feasibility of using charcoal briquets as a fuel, the application of oxygen enriched blast, and the use of new ores and raw ma-terials, in general, can be investigated only at consider-able cost on full sized furnaces, while with an experimental furnace they can be conducted at a com-paratively ;small, cost. The results of small-scale tests are sufficient to determine whether the problem. War-rants the expenditure required for a trial on a com-mercial scale. The accompanying photographs and chart show the various stages of the experimental furnace development. Some idea of the size and shape of furnaces which were tested can be had from the development chart. In oper-ating furnaces A to F, a series of changes were made to increase hearth temperature. Perhaps the most im-portant change was the position of the tuyeres with respect to the bottom of the hearth. The height of the tuyeres above the hearth was gradually increased and the hearth diameter decreased. It was shown by this series of furnaces that metal and slag are the chief source of heat supply to the crucible. For this reason there is a minimum rate at which these materials can be brought into the hearth of a small furnace if it is to function properly. The rate of slag "and metal fall are determined by the burden on the furnace and the rate of blowing. Due to lack of funds necessary to provide ample blowing equipment, hot blast stoves, essential mechani-cal features, and to meet operating expenses, it. was necessary to work with much smaller furnaces, such as G to K shown in the chart. The particular object of these tests was to study the extent to which reactions could be speeded up by decreasing the size of the stock. One decided change, noticed at the beginning of this series of tests, was the effect which coke size had on the production of a strongly reducing gas. Furnace G, 22 in. high, operating on coke crushed to pass 10 mesh, made a gas richer in carbon monoxide than did fur-naces A to F, operating on run-of-the-oven coke.

Jan 3, 1927

By J. B. Campbell, V. V. Valleroy, B. T. Willman, L. W. Powers

A steam drive of heavy oil was field tested in a shallow, low oil-saturation formation near Deerfield, Mo. The pilot was conducted in the Warner formation, a sandstone containing an 18' API oil having 1,000-cp viscosity at the 60F origind reservoir temperature. The formation war at a depth of 160 ft. Steam was injected into nine input wells arranged in an array of inverted five-spot patterns. In the completely confined center pattern, 14 temperature observation wells were installed to obtain thermal data and observe test progress. Late in the test, slugs of ammonia were injected to trace the flow paths of injected fluids. From the test area about 7,000 bbl of oil were produced. Data were obtained on areal and vertical temperature distribution, steam front advance, reservoir fluid movement and terminal saturations. This field test of a steam drive (I) demonstrated the feasibility of the method, (2) confirmed that the low residual oil saturations observed in the laboratory are obtained in the steam-swept region in the field and (3) provided recovery and conformance data for one set of field conditions. INTRODUCTION The Deerfield steam drive pilot test was conducted in a shallow sandstone containing 1,000-cp oil. The venture was undertaken cooperatively by the research and production departments of Carter Oil Co., which organizations have since been consolidated into Esso Production Research Co. and Humble Oil & Refining Co.. respectively. The production department was interested in steam injection at Deerfield because it appeared to be the most promising method of commercially producing this heavy oil deposit. The research department was interested in applying the new recovery method and in evaluating its performance in the field. At the time the test was begun, the initial oil saturation was not well known. Subsequent air coring and early pilot results confirmed that there was too little oil in place for profitable commercial exploitation by steam. Pilot termination at that time, however, would have been premature for evaluating field performance of the process, and the tert was continued to obtain additional data on steam injection as a recovery method. The test was located in Vernon County, Mo., about 10 miles north of the town of Deerfield and only a few miles from the Kansas border. The pilot site was selected as typical of the area. The location represented neither the highest nor the lowest oil saturation region in the acreage under lease in 1954. The steam drive was conducted in the Warner sandstone of Lower Pennsylvanian age. At the test site the top of the Warner occurs at about 160 ft subsurface and the formation is a fine- to medium-grained micaceous sandstone that dips gently to the northwest at the rate of 12 to 15 ft/ mile. A cross-section and permeability profile of the test location are shown in Fig. 1. At the pilot location the average total thickness of the Warner formation is about 43 ft, but the effective thickness for steam drive is 26 ft. Two distinct types of hydrocarbon saturation are apparent. The lower portion of the total sand, averaging about 17 ft thick, contains a very heavy asphaltic material that will not flow under the influence of a steam drive. This bottom interval, referred to as a dead oil residue, was not considered as part of the net sand undergoing steam exploitation. The initial formation and fluid properties of the upper 26 ft in the test area are summarized in Table 1, and variation of oil viscosity with temperature is shown in Fig. 2. Imbibition tests on preserved core samples taken at the end of the pilot test showed that the Warner sandstone was then neutral or slightly water-wet. Initially, the reservoir may have been strongly water-wet as indicated by low relative permeability to water during both water injection testing and early steam injection. PRIOR HISTORY Initial production tests of wells at the pilot site produced water with only a faint show of oil. No gas was produced except at Well 7-W in the pilot area and at another well about 1/3 mile northeast of the pilot. Prior to the start of the steam drive, a two-well water injection test and a two-well air injection test were conducted. No oil was produced by either. Water was pumped into Well I-W in the northeast corner of the pilot area with simultaneous production from Well 1 (Fig. 3). The air-injection tat was run at input Well 9-W and its offset, Well 2, in the southwest corner. Air and water injectivities were about the same when corrected for viscosity and pressure differences.

By Royal Preston Jarvis

minerals of different specific gravities. It is simple in construction, easily operated, capable of treating large quantities in a short time, and highly efficient under various conditions. The question, whether the material to be jigged has first been sized, determines the two principal methods of jigging. Jigging preceded by close sizing, generally known as the Continental or German system, involves a more or less elaborate series of screens or trommels, with attendant cost for installation, operation, and repairs. Jigging without sizing, known as the English system, is, according to Munroe,1 a development of the hand-jigging formerly employed in Cornwall . and introduced by English miners to this country." In its simplest form, the method consists in jigging an ore-mixture previously crushed to some maximum size (although, in some cases, even this preliminary is omitted) oil a relatively coarse sieve, and then jigging again on a filler sieve, the material passing through the first sieve and bedding. While many modifications have been necessary to adapt it for use in mills of large capacity, where hand-work was necessarily, replaced by machines, the principle remains the same; the fact that the English system has been successfully employed, both in this country and abroad, is well known; and arguments have been made for its efficiency and applicability in a wider sphere than it has occupied hitherto. II. REVIEW OF PREVIOUS INVESTIGATIONS. The fact that treating a mixture of minerals under jigging conditions increased the amount of mineral saved, or, as Professor Richards aptly terms it, 1 ?the extra jig-catch," has long been known. To account for this fact a number of theories have been proposed. The work of Rittinger2 in this field has, for many years, been a classic in the literature of ore-dressing. For the purposes of my present paper, however, the work of two American investigators, Prof. H. S. Munroe and Prof. R. H. Richards, is chiefly concerned. Professor Munroe has given the results of an elaborate series of experiments,3 and his deductions, based largely oil theoretical grounds, of this work. After reviewing briefly the two systems of jigging, followed by a discussion of Rittinger's formulas and

Sep 1, 1908

By L. F. Pett

ALTHOUGH Kennecott's orebody has long been outlined, it is still necessary to define further its limits. This mine, long an advocate of churn drill methods, recently supplemented its practice by using a diamond drill. So far, the diamond drill holes have been along the main canyon floor which traverses the mine area. This zone, highly fractured, is cut by numerous friable quartz veinlets encountered within the porphyry. These veinlets, formed by filling contracted porphyry fractures with hot, siliceous, mineral-bearing solutions, are often more highly mineralized than adjacent porphyry. They pulverize on contact, yielding only slight amounts of core. For this reason neither analysis of core recovered (amounting to 37.5 pct of approximately 10,000 ft of hole drilled) nor sludge analysis considered separately would give correct assays. The following equation has been adopted: actual weight theoretical actual weight core — theoretical weight sludge Drilling is done un.der contract. Collection of core and sludge samples together with double-checked assaying is done by the company. Microscopic, specto-graphic, and X-ray examination of rock specimen saved is carried on at the University of Utah. A fund, set up by Kennecott Copper Corp. at the University, has encouraged cooperation in solution of mining research problems. The drill used is a Longyear hydraulic powered by a Waukesha 26-hp gasoline motor. A pump, Bean Royal type, is powered by a 7-hp Briggs-Stratton gasoline motor. Weight of unit is 4000 lb and is placed under tripod of 35-ft wood poles within a 25-ft sq area. The following results have been attained: Avg depth of hole drilled, ft 1215 Avg drilling depth per 8-hr shift, ft 10.11 Core Size, In. Avg depth of NC casing, ft 21 2 11/16 Avg depth of NX casing and size core, ft 178 2Ye Avg depth of BX casing and size core. ft 427 1% Avg depth of AX casing and size core, ft 585 1 5/32 Through the use of metal sludge collection boxes, 12 ft long, 18 in. wide, and varying from 12 to 24 in. in depth, sludge recovery has been maintained above 95 pct. Samples, both core and sludge, are assembled for each sample interval and averaged in 50-ft bench increments. Determinations for mineral values are made at both the mine and mill. Assay results varying in excess of 0.05 of copper assay values are rerun to determine correct assay. The organization chart for the Kennecott Utah copper mine is shown in Fig. 1. The Utah mine requires approximately four men per shovel shift to drill solid rock, properly slope banks, and trim loose material from the top of bench sections in making them safe for men and equipment working below. During recent years, while the mine has been worked day and night, powder crews have worked day shift only. Series of toe holes drilled back of advancing electric shovels comprise approximately 70 pct of all mine drilling. These holes, spaced about 21 ft apart, have a depth of 24 ft. Of the footage drilled, 25 pct is for vertical holes either 24 or 28 ft deep, spaced about 28 ft centers along the top rim of banks. This combination of toe holes, using an Ingersol-Rand DA 35 drifter mounted on a tripod and the vertical holes using an Ingersol-Rand Type X71 wagon drill is standard practice above the pit elevation. These benches are 68 ft high, with a few exceptions, while benches below the pit elevation are 50 ft high and require very little drilling other than toe holes. Five benches, varying in height from 80 to 100 ft, require a combination of toe holes plus vertical holes and bank holes or electric churn drill holes. Bank holes using the DA 35 drifter and electric churn drill using Bucyrus-Erie Model 29T, account for 5 pct of feet drilled. Until the past year, drilling of fill material on upper levels was accomplished by churn drill method. Wagon drills are now used for fills because they can be set up and drill a hole an hour. It is necessary to run an air drill 7 hr for each 8-hr shovel shift. Average drilling rates during the past year were as follows: DA 35 drifter using 2 and 3-man crews — 4.36 ft per man hr X 71 wagon drill using 2-man crews — 6.45 ft per man hr DA 35 drifter bank holes, 3-man crews — 2.53 ft per man hr Bucyrus-Erie churn drill, 2-man crews —1.9 ft per man hr Total mine avg — 4.57 ft per man hr Mine practice assigns powdermen to job locations where they perform all drilling and blasting work within the area. Almost as much labor is consumed in springing and loading holes as in drilling them. Average powder consumption is approximately as follows: Per Electric Shovel Shift, Lb To spring and chamber holes — 50 Blasting — 500 Trim banks — 50 One fifth of all powder used is Hercules hercomite bag powder while four fifths is Hercules gelamite 65 pct strength in 1 Vi in. x 8 in. sticks. Frozen material, overhanging from top banks, creates a winter hazard to shovel operators and equipment. Experiments are being conducted with a high-speed Hercules powder in an effort to eliminate this condition. Banks are trimmed by powdermen who lodge 8 or 10 bundles of powder, containing 15 or 20 sticks each, across the upper surfaces of each working face. To each bundle of powder is attached a primer with 6-ft fuse which is lighted as the powdermen, who have lowered themselves down the bank on ropes, ascend to safety. Three angle dozers, D8 caterpillars, make grades and move supplies for the average 31 drilling machines working daily. Compressed air is furnished by three Ingersol-Rand compressors, each with rated capacity of 3750 cu ft of air per min at 100 lb reservoir pressure.

Jan 1, 1952

By R. I. Jaffee, H. P. Nielsen

In recent years much attention has been given to high melting alloy systems. It has been of interest in this respect to investigate the alloys of platinum and tungsten, which were known from the literature to have very high melting points up to about 50 pct tungsten, but about which little had been published on the high-tungsten side of the system. Powder metallurgical methods were used throughout this investigation for the preparation of the alloys, utilizing electrical sintering techniques such as are used for tungsten and molybdenum. In the course of the work it was found desirable to determine fusion temperatures of the alloys, and it was possible from these and other data to draw a tentative constitutional diagram (solidus, mostly) applicable to the high-temperature part of the system. No attempt was made to determine solid solubility vs. temperature data, nor to investigate the lower temperature transformations in the solid state. Data on the microstructure, hardness, and a note on oxidation resistance of the sintered alloys were obtained. Past Work Miillerl determined liquidus temperatures of platinum-rich alloys to 50 pct tungsten, using a radiation method employing a photoelectric cell, and found that the melting points increased progressively from I771 C for platinum to 2350°C for the 50 pct alloy. Microscopic evidence by Miiller that complete solid solutions exist to 50 pct tungsten was not checked by Kremer2 who, according to Vines and Wise,3 found that "although the 8 pct tungsten alloy was a solid solution, the 26 pct tungsten alloy contained a eutectic or an intermediate phase." Hultgren and Jaffee4 using X ray methods found continuous solid solutions to at least 33.6 pct tungsten (35 at. pct) after annealing in vacuum for 6 days at I000 C. Vines and WiseS report work communicated to them by E. C. Rhodes on wrought alloys to 7 pct tungsten, which showed that tungsten hardened platinum extremely rapidly, and was one of the most potent hardeners of the binary additions to platinum. Considerable quantities of 4 pct tungsten platinum wire have been produced for grids in radar tubes and for aircraft spark plugs. Some of the alloy for the latter application is made by sintering, the remainder by smelting and casting. Materials The platinum powder used in this work was kindly supplied by the Research and Development Laboratory of the Owens-Corning Fiberglas Corp., Newark, Ohio. It was prepared from scrap platinum. After dissolving in aqua regia and evaporating almost to dryness, the solution was worked up several times with concentrated HC1. The resultant platinic chloride was diluted considerably, and metallic zinc was added, which precipitated the platinum in a very finely divided form. After dissolving the

Jan 1, 1949

By Herluf P. Nielsen, Robert I. Jaffee

IN recent years much attention has been given to high-melting alloy systems, It has been of interest in this respect to investigate the alloys of platinum and tungsten, which were known from the literature to have very high melting points up to about 50 pct tungsten, but about which little had been published on the high-tungsten side of the system. Powder metallurgical methods were used throughout this investigation for the preparation of the alloys, utilizing electrical sintering techniques such as are used for tungsten and molybdenum. In the course of the work it was found desirable to determine fusion temperatures of the alloys, and it was possible from these and other data to draw a tentative constitutional diagram (solidus, mostly) applicable to the high-temperature part of the system. No attempt was made to determine solid solubility vs. temperature data, nor to investigate the lower temperature transformations in the solid state. Data on the microstructure, hardness, and a note on oxidation resistance of the sintered alloys were obtained. PAST WORK Müller1 determined liquidus temperatures of platinum-rich alloys to 50 pct tungsten, using a radiation method employing a photoelectric cell, and found that the melting points increased progressively from 1771°C for platinum to 2350°C for the 50 pct alloy. Microscopic evidence by Müller that complete solid solutions exist to 50 pct tungsten was not checked by Kremer2 who, according to Vines and Wise,3 found that "although the 8 pct tungsten alloy was a solid solution, the 26 pct tungsten alloy contained a eutectic or an intermediate phase." Hultgren and jaffee4 using X ray methods found continuous solid solutions to at least 33.6 pct tungsten (35 at. pct) after annealing in vacuum for 6 days at 1000°C. Vines and Wise3 report work communicated to them by E. C. Rhodes on wrought alloys to 7 pct tungsten, which showed that tungsten hardened platinum extremely rapidly, and was one of the most potent hardeners of the binary additions to platinum. Considerable quantities of 4 pct tungsten platinum wire have been produced for grids in radar tubes and for aircraft spark plugs. Some of the alloy for the latter application is made by sintering, the remainder by smelting and casting. MATERIALS The platinum powder used in this work was kindly supplied by the research and Development Laboratory of the Owens-Corning Fiberglas Corp., Newark, Ohio, It was prepared from scrap platinum. After dissolving in aqua regia and evaporating almost to dryness, the solution was worked up several times with concentrated HCI. the resultant platinic chloride was diluted considerably, and metallic zinc was added, which precipitated the platinum in a very finely divided form. After dissolving the

Jan 1, 1948

By G. Sandoz, D. A. Meyn

The fracture surfaces of specimens of titanium a1loys which exhibited susceptibility to subcritical crack growth in a wide variety of environments, including aqueous solutions, alcohols, hydrocarbon gases, carbm tetrachloride, and dry air, were examined. The dominant and characteristic fracture mode was cleavage. which became mixed with an increasing porportion of ductile fracture modes (dimples. and so forth) as the applied KI was increased. The cleavage plane in all the alloys was oriented at 15 deg from (0001) of the a phase. No indices could be assigned to the 15 deg cleavage Plane because of uncertainty as to which zone it belonged to. SLOW crack growth and delayed fracture take place in certain titanium alloys at stress intensity (KI) lower than the critical values for complete fracture (KIc) found in short-time tests for plane strain fracture toughness.' Such crack growth may take place in very dry air on sustained loading if the alloy contains a sufficient amount of hydrogen and if the stress intensity factor is higher than a threshold value designated KIH.2 Similarly, a number of environments such as water, alcohols, and hydrocarbons may cause slow crack growth provided the stress intensity factor exceeds the threshold value KISCC. In this paper it is intended to examine some fracto-graphic and crystallographic details of this subcritical crack propagation process as related to alloy composition, environment, and stress intensity. It has been previously reported that subcritical crack growth takes place in titanium alloys in aqueous environments by cleavage.2"6 The observations to be described here indicate that in the alloys investigated the mode of subcritical crack propagation is more dependent on the stress intensity during cracking than on the environment. The fracture mode is illustrated with photographs of the fracture surfaces at a wide range of magnifications. The crystallographic character of the cleavage mode is also presented and the results discussed. EXPERIMENTAL APPROACH The studies were made on four titanium alloys— Ti-8A1-1Mo-lV, Ti-5A1-2.5Sn, Ti-7Al-1Mo-lV, and Ti-0.350. Of these four alloys the first two were mill annealed and fine grained. The latter two were noncommercial and coarse grained, having been prepared for other experimental purposes. The crystallographic studies required a large-grain size. Consequently the fine-grained alloys were an- nealed in a vacuum at 1950°F and furnace cooled to produce samples for these studies. This treatment did not alter the microstructure significantly except for grain size. All the aluminum-containing alloys showed primary a with a network of ß-phase particles within the a grains; Figs. 1 and 2 show this microstructure for the specific case of fine-grained Ti-8A1-1Mo-1V. The cracks in the figures will be discussed later. Fractographic studies were made on all the alloys, but the electron fractographs displayed herein are from the Ti-8A1-1Mo-1V alloy in the fine-grained condition. Emphasis was placed on this commercial alloy because considerable information was available on the stress-corrosion cracking characteristics in a variety of environments. Sufficient supplementary studies of the alloy after the anneal to produce large grains were conducted to establish that the stress-corrosion cracking susceptibility and fractographic characteristics were not changed significantly. Thus it could be inferred that the crystallographic data obtained exclusively on large-grained specimens would apply also to fine-grained specimens. Fracture surfaces for study were obtained using precracked cantilever beam specimens loaded as described by Brown. The precracked section of a specimen was immersed in the environment of interest. Values of initial stress intensity factor Kli were chosen slightly higher than KISCC in order to obtain a fairly extensive region of slow crack growth. Fracture surfaces representative of a variety of stress intensity levels could then be examined because in the cantilever beam test KI increases as the crack propagates.

Jan 1, 1970

By Ballard H. Clemmons

THE future of the steelmaking industry of the Birmingham, Ala., district is closely related to and, in a large measure, dependent on the development of workable, economic processes of ore concentration. Operations thus far in the area have been possible only because of the fortuitous occurrence of iron ore, fluxing stone, and coking coal-all the primary iron-making materials- within a 25-mile radius of the blast furnaces. Commercial ore of the district consists mainly of a 10 to 20-ft hematite-calcite-silica bed locally known as the "Big Seam," a component of the Clinton formation of Silurian Age. At present mining rates, this ore will be available for a number of years. It is largely mined under 1000 to 2000 ft of cover and transported on 15 to 20" slopes that, in some instances, are as much as 10,000 ft long. Under these conditions, particularly with increasing distances from face to portal, mining costs are gradually becoming disproportionately high. Although not a major factor thus far, it should also be noted that the average annual ore output of the district is gradually be- coming more siliceous.

Jan 1, 1950

By W. R. Ingalls

DUPING the last two years, and especially during the last six months, a number of important articles upon the new methods for the desulphurization of galena have been published in the technical periodicals, particularly in the Engineering and Mining Journal and in Metallurgie. I proposed for these methods the type-name of "lime-roasting" of galena as a convenient metallurgical classification,' and this term has found some acceptance. The articles referred to have shown the great practical importance of these new processes, and the general recognition of their metallurgical and commercial value which has already been accorded to them. It is my present purpose to review broadly the changes developed by them in the metallurgy of lead, in which connection it is necessary to refer briefly to the previous state of the art. The elimination of the sulphur-content of galena has been always the most troublesome part of the smelting-process, being both costly in the operation and wasteful of silver and lead. Previous to the introduction of the Huntington-Heberlein process at Pertusola, Italy, it was effected by a variety of methods. In the treatment of non-argentiferous galena concentrate, the smelting was done by the roast-reduction method (roasting in reverberatory furnace and smelting in blast-furnace); the roast-reaction method, applied in reverberatory furnaces; and the roast-reaction method, applied in Scotch hearths 2 Precipitation-smelting, simple, had practically gone out of use, although its reactions enter into the modern blast-furnace practice, as do also those of the roast-reaction method.

Sep 1, 1906

Discovery of a deposit of magnetite ore estimated at 3 million tons and of quality sufficient to warrant mining has been located near Reading, Pa. by the Bethlehem Steel Corp. Last January; the company spent nearly $400,000 for about 1750 acres of farm land which had been valued at only about $50 per acre. It is expected that a pilot shaft 18 in. in diam will be sunk some time this spring. The ore body, delimited by diamond-drilling by Sprague Henwood, is said to measure roughly 2000 sq ft and 1000 ft thick, beginning 1500 ft below the earth's surface. In a continuing search for strategic minerals, the Atomic Energy Commission expects to put eight to ten diamond drilling rigs into the area 11 miles southwest of Blanding, San Juan Co., Utah early this year. The Commission's primary objective is the Salt Wash member of the Morrison formation. Holes 140 ft deep are expected to be drilled, with solid bit drilling through overburden, mudstone, shale and sandstone overlying the area.

Jan 1, 1951

The Nominating Committee for Institute Officers in 1953, John R. Suman, chairman, completed its work at the Annual Meeting in February, and has made its report to the Board of Directors. The President-Elect in 1953 serves as President in 1954. The ticket follows: For President-Elect and Director, Leo F. Reinartz; for Vice-President and Director, A. B. Kinzel and Lloyd E. Elkins; for Director, Hjalmar W. Johnson, Philip Kraft, Gail Moulton, Edwin L. Oliver, Philip Wilson, and Elmer Isern. Mr. Reinartz is a vice-president of the Armco Steel Corp., Middletown, Ohio. As required by the bylaws, brief biographical sketches of the nominees will be published in the July issues of the journals.

Jan 1, 1952

By Samuel Taylor

IT is customary for the president of an engineering society, in his annual address, to describe either some engineering problem with which he has beer connected or to review the work of the society during his administration. My first thought, this being the sesquicentennial year of our nation, was to review the advance in coal mining for the past fifty years, during which period I have been more or less intimately con-nected with the bituminous coal industry, and have personally witnessed most of the great changes which have occurred in methods and machinery used in the production of coal, but preparation of the requisite address would take more time than could be spared to prepare it, and its presentation would consume so much time that it .would not be suitable. The new arrangement providing for giving the presi-dent's address at the business meeting makes it more .appropriate to review the work of the Institute during the past year, together with some suggestions which appeal to me as being of advantage to the future wel-fare of the Institute, which I will try to do briefly. The work of the business office has been reviewed in the Secretary's report and it will not be necessary for me to dwell on it. Suffice it to say, it seems to be going along very well. Additional work could be done which would be to the advantage of the Institute, if we had the money with which to defray the necessary ex-pense incident to it, but I will refer to this again later. I would be derelict if I did not refer to the splendid work of the Secretary and the Assistant Secretary. Keeping in touch with all the sections, which number now about 26, and affiliated student societies which number 40, besides special committees, and represent-ing the Institute on various boards, provides work enough to occupy the Secretary's time almost exclu-sively. In addition to this the Secretary and the As-sistant Secretary have the work of editing and publishing the TRANSACTIONS of the Institute; the issuing of the magazine, MINING AND METALLURGY, in the splendid manner in which it goes out to the mem-bership is no light task and I think they should receive the commendation of the membership for this work.

Jan 3, 1927

By Ian Wark

IN an earlier paper1 measurements of contact angles due to the effect of xanthates on mineral surfaces were reported. The solutions in which these measurements were made differed widely from those of modern flotation circuits. It is intended, however, by introducing, one at a time, the other principal reagents of flotation, to approach gradually the solu-tion composition of flotation liquors. The work now described is an attempt to determine the effect of one of the most important of these reagents-namely, sodium cyanide-on the establishment of air-mineral contact. The work has been carried out for the following companies: Broken Hill South, North Broken Hill, Zinc Corporation, Electro-lytic Zinc of Australasia, Mount Lyell Mining and Railway, and Burma Corporation. Since the effect of cyanide is inseparably connected with the alkalinity, the results cited below deal with the mutual effects of alkalis and cyanide. Alkalis alone exert a significant effect on the air-mineral contact but comparatively large amounts are required. Since the addition of a small amount of cyanide greatly decreases the degree of alkalinity necessary for the suppression of contact at surfaces of any of the minerals experimented with (except galena) and since alkalis are rarely used alone in practice, little attention has been paid to cyanide-free solutions. It was shown in the previous paper that, excluding the dixanthogen effect, whenever contact was practicable at all in an ethyl xanthate solution the angle of contact was 60°. There is, therefore, less necessity to measure equilibrium contact angles; in fact, the experiments herein described have generally been conducted with a view to determining whether contact is possible and not to measuring the actual value of the contact angle. The separations which have generally to be effected in dealing with complex sulfide ores are: (1) galena from sphalerite, pyrite, etc.; (2) sphalerite from pyrite and/or gangue minerals; (3) copper minerals from pyrite and gangue minerals; (4) pyrite from gangue minerals; (5) chal-

Jan 1, 1933