Search Documents

By Raymond M. Howe

Additional data have been secured on the disintegration of furnace linings and the spalling of stove brick. The first article on the disintegration of furnace linings appears to have been written by John Pattinson in 1876.l The furnace involved was 85 ft. (25.0 m.) higher and 27 ft. (8.2 m.) in diameter at the boshes; after being in blast five years, the top brick became contaminated with carbon and disintegrated. An examination of the lining showed that the discolored, disintegrated brick were in a zone found from 35 to 67 ft. (10.6 to 20.4 m.) above the hearth; immediately below, in a zone extending from 22 to 40 ft. (6.7 to 12.1 m.) above the hearth, the brick were hard and porcelain-like in appearance. Analyses of samples taken from the different sections are given in Table I. The water-soluble portion found in the sample taken 39 ft. (11.8 m.) above the hearth had a composition approximately as follows: silica, 0.50 per cent.; lime, 0.04 per cent.; potash, 0.78 per cent.; soda, 0.20 per cent.; potassium chloride, 6.19 per cent.; moisture, 1.03 per cent.; total, 8.74 per cent. The carbon Table 1.—-Analyses of Samples Taken from Diferent Sections of Furnace . I ii In Iv v Section 67 Section 45 Seotion 39 Section of Original ft Above ft above ft above vitrified Lining Hearth Hearth Hearth Portion Per Cent. per Cent per Cent per cent. per Cent Silica........................... 55.70 55.60 55.67 47.60 37.07, Alumina........................ 35.50 35.40 30.00 26.47 23.18 Ferric oxide..................... 3.00 1.32 0.96 Lime........................... 0.23 0.06 0.17 Magnesia....................... 1.22 0.95 0.86 0.00 Potash......................... 2.60 2.10 5.30 7.54 21.59 Soda.........,.................. 0.45 0.42 1.67 0-76 6.28 Ca1bon ......................... 2.05 3.24 5.97 Carbon dioxide.................................. 2.. 17 Water...................................... 7.70 Water-soluble........................... 8.74

Jan 1, 1920

As already announced, the Arizona Meeting of the Institute is to be held from the 18th to the "25th of September. There will be a special train from New York City to Arizona and return, to take members and guests of the Institute to the meeting., The Committee in charge consists of Walter Douglas, Chairman, Cleveland E. Dodge, John C. Greenway, Arthur S. Dwight and Julius Kruttschnitt, Jr., and while the plans of this Committee are not complete, it may he announced that 'the train will be run with the requisite number of Pullman, dining and baggage cars to accommodate those who desire to go, which will accompany the party during the entire week of the Arizona Meeting as per the following program, including, of course, the visit to the Grand Canyon. It is especially desirable that the Committee should know, at as early a date as possible, the number of those who desire to make the trip; and those who desire special accommodations such as drawing rooms, state rooms, etc., are especially requested to communicate as soon as possible with the Secretary of the Institute, stating the number in their party.

Jan 6, 1916

By George W. Maynard

For an account of the discovery and the determination of chromite on Port au Port Bay I am indebted to Mr. Obalski, Government mining engineer for the Province of Quebec. He writes: " In June, 1894, with the authorization of our Government, I went to Newfoundland to examine some asbestos property. Passing through Halifax, I had interviews with some gentlemen who told me that besides the asbestos there was in the same district a big deposit of iron-ore. They handed me some specimens, and, after ascertaining that they were not magnetic, and learning that they were found in serpentine, I said they were chromic iron. I visited the place on June 27, 1894, and confirmed my opinion, pointing out at the same time the importance of the deposit, as appears in my report of July 9, 1894. I do not claim any credit for the discovery of chrome-ore in Newfoundland; but, as a matter of fact. when I came in contact with the Halifax gentlemen they did not appear to know the nature or the value of the mineral until I mentioned to them that it was chromite. "' Mr. Obalski's report was mainly devoted to the asbestos-deposits. That portion relating to the chromite was as follows: " On the right side of the creek there is a show of chromic iron of good quality, which appears scattered through the serpentine in several places on the face of the cliff for 40 to 50 feet. A few boulders are found farther up at a distance of 100 feet, and also in the ckeek itself. From this point the deposit exists on a relatively large area, the widest exposures being from 6 to 7 feet. Chromic iron deposits in serpentine rock have no regularity, and are merely pockets. In the case of the property in question this rule is not changed, but the pockets look to be of large extent, and could be easily worked." My own preliminary investigation of the property was made

Jan 1, 1898

By Howard V. Sears

ArcHodrilling (Arcuate Hole Drilling) of short radius overhead curved holes from within the working level with a new, small-diameter in-the-hole drill produces tangible, assayable chip samples from the entire height of the projected mine level where the hole arcs down immediately in front of the working face. Drilling through the projected level with diamond coring tools produces samples showing the competence of roof and floor strata as well as the geological and economic characteristics of the ore. Hand-portable solid state electronic surveying instrument has been developed to survey the ArcHole and a convenient nomograph plotting record sheet converts survey digital readouts to hole inclination in degrees, to radius of curvature in feet, and to attitude of the plane of curvature from vertical in degrees, all without calculation. The ArcHodrilling system offers a tool with which the exploration geologist can more nearly assess the true potential of old mining properties being reexamined and to reduce the number of surface diamond drill holes needed to secure development data about new ore bodies. It gives the mine geologist an opportunity to secure those data at a fraction of the cost of drilling from the surface. The mining supervisor has a convenient, cheap tool to look ahead to know what he will be mining tomorrow. The mill supervisor has an opportunity to reduce his mineral loss in tailings by being able to anticipate the grade of his mill feed.

Jan 1, 1973

By Hugh P. Nicholson

IN view of the many articles that have been written on the proper classification of mining systems without so far having produced any particular tangible results it might seem that the subject is hopeless of solution. I do not believe that is so, and my intention in contributing the following outline is to present a slightly different viewpoint. Too much attention is often focused on unnecessary details and not enough on general principles. Too much attention and emphasis is often given to the system employed at one particular mine or in one particular district. In addition, names that are entirely misleading are applied to mining systems, and their adoption by the coming generation perpetuates a condition that needs clarification badly. The following classification is the result of several years of practical experience in mining and also several years' practice in teaching the same subject. It therefore represents a broad picture of the entire field of mining systems from the viewpoint of the miner as well as the teacher. It seems that the difficulty in the past has been in reconciling these two viewpoints. The need of such a reconciliation requires no explanation.

Jan 1, 1934

By A. G. Metcalfe, A. Siede

The hardening of annealed copper during fatigue testing appears to be independent of the applied stress and to occur largely within the first 4000 cycles. Copper hardened by fatigue is more resistant to annealing than copper hardened by static means, and softens by a multistage process. Creep studies at 300°C show that copper hardened by fatigue also has greater resistance to creep than statically hardened copper. Some theoretical explanations are discussed. RECENT interest in the behavior of metals subjected to fatigue stems from observations of phenomena which could not be explained by current theories of the structure of metals. In 1953 Bullen et al.l showed that the hardening caused by fatigue at low stresses did not cause severe bending of the lattice as did hardening by static methods. This was later confirmed by Wood, 'and Broom and Ham.3 Clarebrough et al4 showed that as the stress level used in fatigue hardening was increased, bending of the lattice was introduced, eventually approaching that of metals deformed by conventional cold-working methods. The type of hardening introduced by fatigue has other interesting characteristics. Kemsley5 showed that copper fractured by fatigue at low stresses resisted annealing as compared to copper hardened an equal amount by static means. The work of Clarebrough etal, shows that the manner of energy release during annealing differs for fatigue-hardened and statically hardened metal in both magnitude and temperature range of release. In addition to hardening of the lattice, fatigue has been shown to cause softening in materials previously hardened by static methods,5 and also in age-hardened alloys.7 The superposition of a small fatigue stress on the static loading of high-temperature alloys has been shown to increase their resistance to creep.' The present work was an attempt to determine the relationship between fatigue hardening, resistance to annealing, and the creep properties of pure copper. EXPERIMENTAL PROGRAM The program described here was designed to answer three questions: 1) Can stress-cycle combinations well below the failure values give significant increases in hardness? 2) Does hardening, under different stress-cycle combinations, give increase resistance to annealing? And if so— 3) Does superior resistance to annealing confer superior creep properties over statically hardened material? Three-quarter hard OFHC copper was annealed in vacuo at 550°C for 1 hr to produce a strain-free material having a fine grain size and uniform hardness. (The standard deviation of the mean hardness of the annealed samples was less than + 1.9 Dpn). Annealing was performed after machining the fatigue specimens so as to avoid work-hardened surfaces. Jigs were used to avoid distortion. The fatigue properties of the annealed copper were determined using an accurately aligned Baldwin-Sonntag SF1-U machine operating at 1800 cycles per min. This limited the minimum number of cycles which could be examined to about 4000 stress reversals. Since failure resulted in specimen damage, hardness increase with number of cycles was measured by testing specimens fatigued to different fractions of the failure values. The results are shown in Fig. 1, and are superimposed on the S-N curve of the copper in Fig. 2. The resistance to annealing of fatigue-hardened material was compared to that of material hardened by uniaxial tensile straining. Specimens hardened to equal values by both methods were progressively annealed for 1 hr at temperature in vacuo. After each annealing treatment the hardness was measured using a Leitz Durimet hardness tester with a 500-g load. At least five tests were made for each hardness determination. The standard deviation for individual specimens varied from 0.26 to 1.48 hardness points. The results are shown in Figs. 3 to 5. The discontinuous nature of the annealing process has been brought out by drawing idealized curves through the data points. This can be justified by the consistency of the results as well as by general agreement with results of Kemsley.5 The creep resistance of fatigue-hardened and

Jan 1, 1960

By Clyde Evarts Weed

SOME one once affirmed his great belief in luck, adding that he had found that the harder he worked the more luck he had. Clyde Weed is a firm believer in this method of courting the fugitive lady. He is at work early and late, often leaving his staff at Anaconda's offices at 25 Broadway breathless trying to keep up with the ideas teeming from a fertile brain and the actions those ideas entail. Miles ahead of his assistants much of the time, he still manages to be an agreeable fellow to work with, no small accomplishment as many can testify. Mr. Weed arrived in the world at Moorestown, Mich., on Aug. 8, 1890. Sixteen years later he entered Michigan Agricultural College, a lowly freshman. The following year, with the experience and wisdom expected of a sophomore, he transferred his studies from the reaping of a harvest on the surface of the earth to delving into the deeper, unpredictable bowels of the earth, his studies now shifted to the Michigan College of Mines. Last June his alma mater conferred upon him the degree of Doctor of Engineering.

Jan 1, 1947

By Chung Yu Wang

During the time I was in charge of this mine, from 1914 to 1915, I had occasion to read the interesting papers by T. T. Read and C. M. Weld about these deposits, to find how far their observations corroborated mine. To quote from the paper on "The Mineral Production and Resources of China" by T. T. Read:' "The iron ores at Tayeh * * * * lie along the contact between a marble and an intrusive body of a dark gray syenitic rock. * * * * At one place it is slightly magnetic, apparently having been partly reduced to the magnetic oxide by the action of reducing solutions, which have deposited small amounts of copper and iron sulphides along the foot wall." To quote from the paper on "The Tayeh Iron Ore Deposits"2 by C. M. Weld: "I find the orebodies described as occurring along an approximately E-W contact between hornblende-granite and limestone. * * * * The granite is a granitoid rock consisting essentially of quartz, potash-feldspar and hornblende."' These quotations show the differences of opinion entertained by two observers. My own study of these interesting deposits has been intermittent amid the manifold duties devolving upon a superintendent. General DescriptLon of the Deposits The deposits are situated to the west of the Yangtse River, being connected with the river by a standard-gage railroad of 66 li (18.16 miles, 26 km.) in length, as shown in Fig. 1. The general topography of the region is of mature age, showing broad valleys with sluggishly meandering streams. These deposits are worked as two mines, named the Tieh Shan Mining Department and the Teh Tao Wan Mining Department; the former consisting of three orebodies more or less connected, named Tieh Man Kan, Sha Mau Tze and Lung Tung, and the latter consisting of Chang Pei Shan, Sze Tze Shan, Ta Shih Men, Yeh Chih Ping and Tsin Shan, also more or less connected, as shown in Fig. 2.

Jan 1, 1918

By C. R. Keyes

Discussion of the paper of C. R. Keyes, presented at the Chattanooga meeting, October, 190S, Bulletin No. 26, February, 1909, pp. 119 to 166. E. R. BUCKLEY, Flat River, Mo. (communication to the Secretary*) :-Some statements in the paper of Mr. Keyes relative to the nature and formation of the Ozark lead- and zinc-deposits seem to me erroneous and misleading, and I respectfully present the following criticisms, placing Mr. Keyes's original statements in quotations. Referring to the Ozark dome: (P. 127.) "It is a region that has been repeatedly upraised and planed off, until in the middle portion the oldest known' rocks only are exposed." Does he mean that the St. Francois mountains, which have always been considered as lying on the eastern flank of the Ozark dome, are the middle of the dome? Or does he mean that the Cambrian rocks of the generally-accepted middle are the oldest known rocks ? Certainly not the latter, and if the former, his idea of the middle of the dome is not in accord with that of others who are familiar with the region. (P. 138.) " . . . the ore-deposits are definitely associated with, or localized by, geologic structures of some kind that .produce in effect basins in which' the underground waters are impounded, or their flow retarded." This statement does not appear to be altogether consistent with the facts, since the ore- bodies of the Joplin district, as the rule, occur in those parts of the Mississippian formation which have a tendency to accel¬erate the flow of ground-water rather than retard it. I might name the open, breeciated ground near Joplin, Webb City, and Oronogo as especially noteworthy illustrations. The ore-bodies, everywhere, occur in positions where there must have been a free and copious circulation of dilute lead- and zinc-solutions in the presence of reducing constituents. The inequalities in the distribution of the ore-deposits are

Oct 1, 1909

By Chung Yu Wang

DURING the time I was in charge, of this mine, from 1914 to 1915, I had occasion to read the interesting papers by T. T. Read and C. M. Weld about these deposits, to find how far their observations corroborated mine. To quote from the paper on "The Mineral Production and Resources of China" by T. T. Read:' "The iron ores at Tayeh lie along the contact between a marble and an intrusive body of a dark gray syenitic rock. * * * * At one place it is slightly magnetic, apparently having been partly reduced to the magnetic oxide by the action of reducing solutions, which have deposited small amounts of copper and iron sulphides along the foot wall." To quote from the paper on "The Tayeh Iron Ore Deposits"2 by C. M. Weld: "I find the orebodies described as occurring along an approximately E-W contact between horn-blende-granite and limestone. * * * * The granite is a granitoid rock consisting essentially of quartz, potash-feldspar and hornblende." These quotations show the differences of opinion entertained by two observers. My own study of these interesting deposits has been intermittent amid the manifold duties devolving upon a superintendent. General Description of the Deposits The deposits are situated to the west of the Yangtse River, being con¬nected with the river by a standard-gage railroad of 56 li (16.16 miles, 26 km.) in length, as shown in Fig. 1. The general topography of the region is of mature age, showing broad valleys with sluggishly meandering streams. These deposits are worked as two mines, named the Tieh Shan Mining Department and the Teh Tao Wan Mining Department; the former consisting of three orebodies more or less connected, named Tieh Man Kan, Sha Mau Tze and Lung Tung, and the latter consisting of Chang Pei Shan, Sze Tze Shan, Ta Shih Men, Yeh Chih Ping and Tsin Shan, also more or less connected, as shown in Fig. 2.

Jan 3, 1917

F. E. BACHMAN, Buffalo, N. Y. (Communication to the Secretary) : The investigation so fully described by Mr. Laudig was undertaken with the idea of determining if it is possible to learn by expesiment, without an actual trial in the furnace, what economical results can be expected from the use of a given ore-mixture. The research was necessarily preliminary, and the results obtained are only to be depended upon so far as they relate to the samples treated. With the exception of the ores obtained from the stock-piles of the Buffalo Furnace Company, and several samples taken at a neighboring furnace, there is no certainty that the ores represented the average shipments of any mine. For this reason the publication of the names of the ores might do producers a great injustice. The names of the ores arc therefore withheld, and their identity is further .veiled by leaving out of the analyses the phosphorus-contents. The investigation was begun with the preconceived idea that the rate of reduction would be found to be dependent upon the accessibility of the particles of the ore to the action of the reducing-gas. In other words, a spongy, brown hematite or a very fine Mesabi would be the easiest reduced. I had formed a scale with No. 21 first, No. 30 second, No. 1 third, Nos. 5, 24, 25 and the remaining Mesabis fourth, etc , which is sufficient to show how much actual results differ from a judgment based on physical characteristics. The ore expected to be most easily reduced proved to be 25th in the list, while the one placed

Jan 1, 1897

By Martin Rubenstein

CdS crystals have been grown from a number of metallic solvents such as bismuth, tin, lead, and cadmium. Etching studies have shown that plastic deformation occurs if the crystals are not removed from the solvent prior to the solidification of the solvent, on cooling. The deformed crystals show a umique exciton fluorescence as a function of edge dislocation density. If one grows the CdS in the eutectic alloy of the above four metals (commonly called Wood's metal) the crystals can be removed from the solvent with hot water and no plastic deformation occurs. In this paper, the liquidus solubility measurements of CdS, as a function of temperature, are presented. The data were obtained using a high -temperature filtration technique. CADMIUM-SULFIDE crystals have been grown from a number of metallic solvents1 such as cadmium, bismuth, tin, and lead. Liquidus solubilities of CdS in cadmium,2 bismuth,3 and tin4 have already been measured. Crystals of CdS, in all four metals, have been grown by solution growth: 1) by cooling a saturated solution and 2) by a solution transport method.1'"1 CdS crystals grown in these four solvents have a few characteristics in common: 1) 1.8°K photolumines-cent emission consisted mainly of the radiative recombination of the bound exciton commonly known as I,, 2) slip lines which could easily be seen by the naked eye, and 3) edge dislocation densities in the order of l05 per cu cm.1 It was decided that these slip lines and the high edge dislocation densities were caused by a plastic deformation of the CdS crystals. It was felt that this plastic deformation did not occur during the growth of the crystals nor during the cooling of the solution, but did occur when the solvent which was in contact with the crystals froze. If these assumptions were valid, the slip lines and the high number of dislocations could be reduced or eliminated by removing the crystals from the solvent before the solvent froze. Since crystals of CdS had already been grown separately in such solvents as bismuth, lead, tin, and cadmium, it was felt that crystals could be grown in a eutectic mixture of these four metals. In this work a eutectic (or near eutectic) mixture of bismuth, lead, tin and cadmium in the proportion 50, 26.5, 13.5, and 10 wt pct, respectively, was used to grow CdS crystals. Such a mixture has a melting point of about 70°C and is close in composition to the alloy commonly known as Wood's metals. If the crystals could be grown from this mixture of solvents, and if hot water (>75°C) could be used to separate the crystals of CdS from the metallic solvent, it was hoped that CdS crystals could be grown with little or no plastic deformation which had been ob- served when crystals were grown from these solvents uncombined. CdS crystals were grown from this low melting eutectic mixture of bismuth, lead, tin, and cadmium using the solvent transport method. CdS powder and the appropriate amount of metals were sealed in a quartz tube under a pressure of about 5 X 10-6 torr. This ampule was then placed in a vertical position in a furnace. The temperature was raised to about 900°C. The furnace was designed so that the top of the liquid column within the ampule was between 10° to 40°C higher than the bottom of the liquid column. These temperatures were measured on the outside of the quartz ampule. The ampule was maintained at temperature for 7 to 14 days (depending on the temperature at which transport was taking place) and then the furnace temperature was lowered until the temperature was about 125°C. The ampule was then removed from the furnace, placed in water maintained at about 90°C, and opened in this 90°C environment. The crystals could then be removed from this two-phase liquid (Wood's metal and water) by mechanically picking them out. Alternatively, the crystals could be quantitatively removed by adding an excess of mercury to the mixture of metals, crystals, and hot water. The hot solution of metals and the hot water could be evacuated using a small diameter tube connected to a vacuum. Small amounts of mercury and water could be removed by heating the crystals in vacuum. Crystals prepared using this technique showed no evidence of slip. However, some of these crystals did show edge dislocation densities as high as l04 per cu cm. Some few selected crystals showed no dislocations. Single crystals of CdS were grown as large as 5 by 5 by 0.5 mm. The ampules for the growth of these crystals were 13 mm O.D., 11 mm I.D., 150 mm! LIQUIDUS SOLUBILITY MEASUREMENTS The CdS starting materials was G.E. 118-8-2 powder which was fired in H2S at 1000°C, and then a vapor transport technique5 was applied to produce a "sound" mass of CdS. The Wood's metal was prepared by weighing out bismuth, lead, tin, and cadmium in the proportions of 50, 26.5, 13.5, and 10 wt pct, respectively. The bismuth, cadmium, and lead were from the American Smelting and Refining Co. (ASARCO) and all had purities of 99.999+ pct. The tin was 99.9999 pct spectroscopic grade from the Vulcan Materials Co. The appropriate mixture was placed in a quartz tube, evacuated to a pressure of 5 X 10-6 torr, melted to a liquid, cooled to room temperature under this same vacuum. This ingot was then placed in another quartz tube, evacuated to 5 x l0-6 torr, and sealed off under vacuum. The ampule was then horizontally placed in a furnace. The temperature was raised to 600°C, and over a period of several hours the ampule was vigorously shaken several times. The ampule was then removed from the furnace, and the metallic liquid was

Jan 1, 1970

By D. L. McElroy, J. L. Schroder

Although the earliest use of rubber-tired haulage was in Illinois in 1936, the first unit of this type of equipment used in West Virginia was shipped into the state in 1938. All units placed in West Virginia mines have been of the shuttle-car type. The Katherine Coal Mining Co., at Lumberport, W. Va., was the second company in the United States to install shuttle cars and the Gay Coal and Coke Co., at Mt. Gay, W. Va., was the first company in the country to install the thin-bed type of shuttle car. On Oct. 8, 1940, nine companies in the state were using 41 shuttle cars, of which 10 cars at three mines were of the thin-bed type. All shuttle cars of the low type were in the southern fields and all of the high type were in northern West Virginia. At that time several units were in the process of delivery. The data in this paper were collected in the field by Mr. Schroder in connection with graduate work on mechanical loading of coal in West Virginia by mobile loaders. In the course of his field work he visited five mines in the state that were using shuttle cars. All of these mines were in high-volatile coal beds of strong structure. The more pertinent data obtained at the mines visited are given in Table I. The maximum distance of shuttle-car haul is the distance between the transfer station and the farthermost place. Tonnage per loading unit per foot of bed thickness is to some degree a measure of relative efficiency, especially if the different operations are working the same bed or have somewhat similar conditions. The thin-bed operation is well up in the higher bracket of the afore-mentioned column, which is as

Jan 1, 1942

By J. L. Schroder, D. L. McElroy

Although the earliest use of rubber-tired haulage was in Illinois in 1936, the first unit of this type of equipment used in West Virginia was shipped into the state in 1938. All units placed in West Virginia mines have been of the shuttle-car type. The Katherine Coal Mining Co., at Lumberport, W. Va., was the second company in the United States to install shuttle cars and the Gay Coal and Coke Co., at Mt. Gay, W. Va., was the first company in the country to install the thin-bed type of shuttle car. On Oct. 8, 1940, nine companies in the state were using 41 shuttle cars, of which 10 cars at three mines were of the thin-bed type. All shuttle cars of the low type were in the southern fields and all of the high type were in northern West Virginia. At that time several units were in the process of delivery. The data in this paper were collected in the field by Mr. Schroder in connection with graduate work on mechanical loading of coal in West Virginia by mobile loaders. In the course of his field work he visited five mines in the state that were using shuttle cars. All of these mines were in high-volatile coal beds of strong structure. The more pertinent data obtained at the mines visited are given in Table I. The maximum distance of shuttle-car haul is the distance between the transfer station and the farthermost place. Tonnage per loading unit per foot of bed thickness is to some degree a measure of relative efficiency, especially if the different operations are working the same bed or have somewhat similar conditions. The thin-bed operation is well up in the higher bracket of the afore-mentioned column, which is as

Jan 1, 1942

By A. U. Seybolt

The solubility limit of oxygen in columbium has been determined in the range between 775' and 1100°C by means of lattice parameter measurements and microscopic examination. The solubility is a function of temperature and varies, in the range given above, from 0.25 to 1.0 pct O, respectively. BECAUSE of the marked deleterious effect of oxygen upon the mechanical properties of some of the transition metals, it is desirable to know something about the solubility of oxygen in these metals. The brittleness caused by oxygen in solution is particularly marked in the case of the group VA elements, vanadium, columbium, and tantalum. The solubility of oxygen in vanadium has already been reported in an earlier paper,' and Wasilewski2 has given a value (0.9 wt pct) for the solid solubility of oxygen in tantalum at 1050°C. Brauer3 in 1941 investigated the Cb-0 system up to Cb2O5, but made no real effort to investigate the extent of oxygen solubility in the metal. He made the observation, however, that this solubility must be less than 4.76 atom pct (0.86 wt pct) oxygen. This estimate was made from X-ray diffraction results on the alloys CbO, CbO, and CbO; all alloys consisted of the terminal (Cb) solid solution plus CbO, but the last alloy containing 4.76 atom pct 0 showed only three very weak CbO lines. It is surprising that Brauer, by examining only three alloys, arrived at an estimate of the solubility which agrees very well with the results to be reported herein. Experimental Procedure A columbium strip obtained from Fansteel Metallurgical Products was cut into strips, 0.020x1/2x2 in. Two holes, about 3/16 in. in diameter, were made near the ends of the strips in order to hold them against a flat steel block for mounting in a General Electric X-ray spectrometer for lattice parameter measurements. The same holes were used to hang the specimens inside a fused silica vacuum furnace tube which was part of a Sieverts' gas absorption apparatus. The apparatus and method of adding oxygen gas has been previously described.1 According to the supplier, the columbium obtained had the analysis given in Table I. After degreasing the samples, approximately 0.001 in. was etched from each side of the samples in order to remove possible surface impurities from the last rolling operation. For this purpose the following cold acid pickle was found satisfactory: 8 parts HNO3, 2 parts H2O2 and 1 part HF. Various Cb-O compositions were obtained up to 0.75 wt pct O by the gas absorption and diffusion technique. After the sample had absorbed all the oxygen gas added at 1000°C, an additional 24 hr was allowed for homogenization. This treatment appeared to be adequate, as shown by the linearity of the lattice parameter-composition plot. More concentrated alloys were prepared by arc melting mixtures of Cb and Cb2O5 since it was very time-consuming to make Cb-0 alloys in the neighborhood of 1 pct O, or over, by the diffusion method. When the flat strip specimens were used, they were ready for the X-ray spectrometer after cooling from the Sieverts' apparatus. The cooling rate obtained by merely allowing the hot fused silica furnace tube to radiate to the atmosphere (when the furnace was lowered) was sufficiently fast to keep the dissolved oxygen in solution. Arc-melted alloys were reduced to —200 mesh powder in a diamond mortar, wrapped in tantalum foil, sealed off in evacuated fused silica tubes, and then heat treated as indicated in Table 11. The fused silica tubes were quickly immersed in cold water without breaking the tubes after the heat treatments. The tantalum foil prevented reaction between the fused silica and the sample; there was no reaction between the powdered samples and the foil at 1000°C, but some trouble was experienced at 1100°C. At this temperature level a reaction between the sample and the foil was sometimes observed, which resulted in erroneous parameter values. Experimental Results Hardness Tests: Since most of the X-ray samples were in the form of flat strip, it was convenient to obtain Vickers hardness numbers as a function of oxygen content. Compared to the V-O case,' oxygen hardens columbium much more slowly, presumably because of the larger octahedral volume in colum-bium (about 12.0 compared to 9.3Å3 in vanadium), hence, requiring less lattice strain for solution. The plot of VHN vs wt pct O is shown in Fig. 1.

Jan 1, 1955

By J. C. Boswell, J. D. Crawford

IN addition to its base-metal and coal mining operations, the United States Smelting Refining and Mining Company has, for the past quarter century, been one of the few large American mining companies interested in dredging. Its activities in this field are confined to gold, and to Alaska, but it is the largest operator in that territory, with twelve huge dredges available to work during the summer on the frozen ancient beach sands at Nome and the gravels of Fairbanks. These operations will be described separately.

Jan 1, 1948

By Robert G. Woolery, S. Ramachandran, James A. Weber, Donald J. Hansen

Union Carbide began looking seriously at heap leaching in 1971. At that time some 1.6 million tons of mineral averaging 0.40 kg U3O8 /t) (0.80 lb U3O8) were stockpiled at various sites around the Gas Hills, Wyoming, uranium facility. Several alternatives for economically exploiting these reserves were considered and heap leaching seemed the most attractive. At the time, Western Nuclear Inc. was operating a heap leaching project nearby in which the low-grade ore was leached with sulfuric acid, the product liquor treated in an on site solvent extraction circuit, and the stripped product liquor re-acidified and recycled. The operators were most generous in allowing us to visit their site and in answering our questions. They were also helpful in discussing the problems associated with heap leaching. Their experience confirmed our belief that it was possible to operate a heap leach profitably on material too low grade for conventional milling. Based largely on what we had learned from Western Nuclear's experience, we undertook a program involving a laboratory study to determine the characteristics of the mineral stockpiles, as related to heap leaching, and to conduct a pilot heap leach adjoining our Gas Hill mill. Basically the pilot heap construction and leach procedure were similar to those described in the literature l, 2 with certain modifications to permit detailed monitoring of the operation. In May 1972, the decision was made to construct a test heap. The UCC plant at Gas Hills, Wyoming was selected as the most appropriate site for the following reasons: (1) The necessary equipment for heap construction was readily available. (2) Stockpiles of mineral from the various mining sites were on hand: (3) Construction of the heap could be made on an abandoned tailings pile minimizing problems associated with environmental approval. (4) Proximity of the mill would allow product streams to be absorbed into existing circuits. (5) Necessary utilities were available. (6) Tailings water from the existing circuit could be used for leaching. A program for the pilot heap leach was developed with the following primary objectives. (1) To confirm the data obtained in bench-scale tests particularly on uranium recovery, acid usage, and ore permeability. (2) To evaluate plastic liners used for base preparation. (3) To investigate heap configuration variables. (4) To determine heap leach amenability of the different mineral sources. (5) To establish the economics of heap leaching low-grade ores.

Jan 1, 1979

By C. S. Simons

Manufacturers of filtering, thickening or clarifying equipment, have been active in developing machines to meet increasingly rigid operator requirements, and the innovations resulting from this effort are moving into commercial applications. In general, the results of these applications are reported to be good. Little has been reported on progress in theory. The growing insistence on the part of pollution control agencies that waste water discharged into streams contain less and less suspended solids is being felt by a broad cross section of industry. A new clarifier, based on the often rediscovered fact that suspended solids settle more rapidly in inclined channels, is being marketed by Neptune MicroFLOC of Corvallis, Ore. This unit employs modules of inclined tubes, mounted in the upper zone of the clarifier, which carry the water flow. These were developed for light solids, such as those encountered in domestic water treatment and in paper mill waste water. In these applications, flow rates up to about three times those permissible in conventional clarifiers are reported to give comparable overflow turbidity. By combining these units with mixed media filters, high clarity may be obtained with minimum capital. Use of such units in the metallurgical industry, particularly where water reuse or effluent quality is important, should grow.

Jan 1, 1970

For the year ending February, 1918 PRESIDENT PHILIP N. MOORE ST. Louis, Mo. PAST PRESIDENTS WILLIAM L. SAUNDERS NEW YORK, N. Y. L. D. RICKETTS, NEW YORK, N. Y. FIRST VICE-PRESIDENT SIDNEY J. JENNINGS, NEW YORK, N. Y. TREASURER GEORGE C. STONE, NEW YORK, N. Y. SECRETARY EMERITUS ROSSITER W. RAYMOND,.. NEW YORK, N. Y. SECRETARY BRADLEY STOUGHTON NEW YORK, N. Y.

Jan 3, 1917

For the year ending February, 1917 PRESIDENT L. D. RICKETTS, 1............... NEW YORK, N. Y. PAST PRESIDENTS BENJAIMN B. THAYER.1 ............... NEW YORK, N. Y. WILLIAM L. SAUNDERS,P ................ NEW YORK, N. Y. FIRST VICE-PRESIDENT SIDNEY J. JENNINGS,1 .....,...... ., .... NEW YORK, N. Y. TREASURER GEORGE C. STONE,l. ................ NEW YORK, N. Y. SECRETARY EMERITUS ROSSITER W. RAYMOND, .... .,. .......... NEW YORK, N. Y

Jan 9, 1916