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By William L. Lennemann

Chemistry of uranium with respect to its hydrometallurgical recovery from carnotite ores was investigated and well defined during the radium boom period between 1900 and 1920. Since that time, methods used to extract uranium from its ores have remained basically either acid leaching or sodium carbonate leaching. Until about 1950, the only practical methods known for achieving a better than 75 pct U2O3 concentrate from the leach liquors involved fundamental chemical techniques for either purifying a solution prior to the uranium precipitation, or refining a crude uranium concentrate that was produced by neutralizing a pregnant mill liquor.

Jun 1, 1956

By R. F. Domagala, M. Hansen, D. J. McPherson

Iodide zirconium was combined with calculated amounts of nitrided zirconium sponge and arc melted to prepare alloys in the 0 to 6 wt pct N region. Annealing treatments were carried out at 21 temperature levels. Metallographic examination of the heat-treated specimens permitted construction of the binary phase diagram from 0 to 6 pct N. Features of the diagram include the peritectic formation of both a and ß solid solutions. The maximum solubility of nitrogen is 0.8 pct in 8 zirconium and 4.8 pct in a zirconium. An X-ray study of nitrided materials was made in the range 6 to 13 wt pct N region because serious nitrogen losses were experienced when attempts were made to arc melt these high nitrogen alloys. PHASE relationships in the Zr-N system have been determined. Due to the inability to retain nitrogen in nitrogen-rich alloys subjected to arc melting, definitive work was possible only in the range 0 to 6 wt pct (0 to 30 atomic pct) N. Sufficient complementary X-ray work was done to permit construction of the binary phase diagram up to 13.3 wt pct (50 atomic pct) N (ZrN). Small ingots were prepared by arc melting master alloys with enough zirconium to produce an alloy of the desired composition. Following pretreatment, alloys were annealed at temperature levels between 600" and 2020°C. Determination of the phase boundaries was then accomplished by metallographic evaluation of specimens quenched from the various temperatures. Incipient melting techniques were used to corroborate solidus curves, and X-ray diffraction was employed to study the nitrogen-rich region of the a + ZrN phase field. Materials Westinghouse Grade 1 iodide zirconium crystal bar served as the base material for this investigation. The as-received bars were lightly sandblasted, pickled in a 20 pct HN0-5 pct HF aqueous solution, rinsed in water and acetone, and dried. They were rolled to about 1/32 in. strip and acid-pickled, followed by water and then acetone rinses. The material was sheared to approximately 1/4 in. squares, cleaned with acetone, and stored for use. Pure zirconium nitride is not commercially available, according to correspondence with possible suppliers. A literature survey indicated that nitrogen may be introduced into zirconium metal by passing nitrogen or ammonia gas over zirconium at an elevated temperature. After considerable experimentation, a train was devised whereby high quality nitrogen was passed through a series of bubblers to remove the last traces of oxygen, through an H,SO, bubbler and a cold trap to remove moisture, and finally over zirconium within a resistance furnace. Hand-picked Bureau of Mines magnesium-reduced zirconium sponge proved more amenable to nitriding than the crystal bar. The nitrogen used was extra pure gas purchased from Linde Air Products Co. The first two bubblers through which the gas was passed contained a solution suggested by L. F. Fieser" as being ideal for removing the last traces of oxygen from nitrogen. The solution contains 20 g KOH, 2 g sodium-anthraquinone ,9-sulphonate, and 15 g NaHSO, dissolved in 100 ml water. It is blood-red and turns brown when contaminated with oxygen. A saturated lead acetate solution, next in the series of bubblers, removed any H2S which might have formed in the 0, removal stage. An H,SO, bubbler and cold trap removed moisture before the nitrogen was passed over the zirconium. The zirconium was contained in a stainless steel screen within a Vycor or quartz tube in a resistance furnace. Unreacted nitrogen passed out of the system through a mercury bubbler. A nitriding run was performed in the following manner: Zirconium was placed in the screen within the furnace tube. The unit was assembled, suitably clamped off, and evacuated to remove the air and moisture within the tube and that trapped by the zirconium sponge. The unit was flushed with nitrogen and evacuated twice. After nitrogen was allowed to pass over the zirconium for about 30 min, the furnace was turned on; several hours were required to reach temperature. The reaction was allowed to continue at temperature for about 4 hr and the screen was then withdrawn from the hot zone of the furnace by means of a Nichrome or Kanthal rod. The screen and its contents were allowed to cool at the end of the tube and were then removed. At 800°C no more than about 5 pct N could be introduced into the sponge zirconium. This material was designated M-1 (master alloy No. 1) and reserved for the preparation of alloys in the dilute nitrogen region. A second set of experiments was conducted at 1000°C; no more than 7.2 pct N could be introduced into the zirconium at this temperature. Enough material (M-2) of this nitrogen content was prepared to produce a second set of alloys to complement the first and to provide alloys in the 0 to 6 wt pct N range. It was hoped that a diffusion anneal plus a re-nitriding might yield a material of higher nitrogen content. The material containing about 7 pct N was therefore given a homogenization treatment at 1000°C for 6 hr under an argon atmosphere. It was

Jan 1, 1957

?AARONSON, ALFRED E , Vice-Pres , Mid-Co Petroleum Co, Mid-Co Bldg, Tulsa, Okla '18 ABADIE, EMILE R, Min Engr Address wanted '76 || ABADILLA, QUIRICO A, Geol Dept, Cia Mexicana de Petroleo "El Aguila," S A, Edifico "El Aguila," Esq, Calles Aurora y Comercio, Tampico, Tamaulipas, Mexico '20 ABBOTT, CLARENCE E, Gen'l Supt, Iron Mines Div, Tenn Coal, Iron & R R Co, 1405 Minnesota Ave, Bessemer, Ala '04 ABBOTT, LOUIS BENJAMIN, Chief Engr, Consolidation Coal Co, Elkhorn Div, Jenkins, Ky '15 ABBOTT, ROBERT R Met Engr, Peerless Motor Car Co, Cleveland, Ohio '12 ABE, ASAKA Fujita Min Co, Dojima, Osaka, Japan '14 ABEEL, GEORGE H, JR, Cons Min Engr, 635 St Paul Ave, Los Angeles, Cal '18 ABEL, ALBERT E, Asst to Pres, Valley Mould & Iron Corpn, Sharpsville, Pea '19 ABEL, W D, Min Engr Forum Bldg, Sacramento, Cal '19 ABELL, O J, Pres & Treas, Abell-Howe Co, 332 South Michigan Ave, Chicago, Ill '19 ABERNATHY G E Willow Springs, Mo '20

Jan 1, 1923

By S. R. Mitchell, M. Weissman, J. H. Brown

It has been demonstrated that for fine grinding operations, the energy input (E) and the product size modulus (k) are related by an equation of the form E = Ak1-n (1) where "A " and "n" are constants.(1) Also, it was suggested that "A" is determined by the comminuting device and that "n" depends primarily on the rock. It was the purpose of this investigation to study these constants by determining the form of an energy-size reduction relationship over an extreme range of energy inputs, and at the same time, to evaluate the minimum particle size produced during grinding. The comminution system consisted of a stainless steel laboratory ball mill in which quartz was ground at 60% solids for times ranging from 1 minute to 700 hours. The mill which measured 10" diameter by 12" long was loaded with about 60 pounds of balls ranging in diameter from 3/8" to 1-1/8" and was driven at 55 r.p.m. Quartz was selected for the tests because it is a brittle material for which size distribution data were expected to show a constant distribution coefficient regardless of product size.(1) This permitted specification of product size by a size modulus alone. The quantities measured were the time of grind (measure of energy input) and the specific surfaces of the products. Since no accurate method is available yet for determining particle size directly in the very fine size ranges specific surface data were used for this purpose. The relationship between these two quantities may be expressed as where Cis a constant which includes a shape factor, p is the specific gravity of the solid,_S is the specific surface and D is an equivalent particle diameter. For a material in which the distribution coefficient does not change with size the term (l/S) may be substituted for k in equation L if the proportionality constant "A" is changed correspondingly. This substitution was made in this work but in addition, screen analyses were made on several products to verify the equivalence of the two methods of size specification. EXPERIMENTAL DETAIL QUARTZ Quartz from two sources was tested. One series of tests was made on a clear, high purity crystalline quartz from Brazil and Arkansas, and another series was run on massive quartz fromNewHampshire. Grinding charges of the high purity material consisted of 2000 gram samples of -3-8 mesh particles, while the charges of the New Hampshire quartz were 500 gram samples of a -35+48 mesh screen fraction. The difference in the sizes of these two series of charges was not significant in view of the extreme size reduction accomplished, and the New Hampshire samples were smaller to permit ginding to finer sizes in shorter times than required for 2000 gram lots. SAMPLING AND ANALYSIS Separate charges were ground for all tests in which the grinding times were less than one hour and for all tests on New Hampshire quartz since these products were difficult to sample accurately without affecting the entire charge. During the long time grinding tests the mill was

Jan 1, 1961

By John B. Myers

VERMICULITE is a name used to describe micaceous material that exfoliates when heated. It is hydrated magnesium-aluminum-iron silicate. The chemical composition, color, physical appearance, and degree of exfoliation vary. COMPOSITION, PROPERTIES, AND ORIGIN Vermiculite has the characteristic micaceous structure of basal cleavage and readily splits into thin laminae, which are soft, pliable, and inelastic. The monoclinic crystal faces are often marked by triangular lines at 60° and 120°. Hardness is 1.5; specific gravity, 2.2-2.7; luster pearly to greasy; colors, amber, bronze, reddish brown, dark green, and black. Feel is soapy, particularly when wet. When heated it exfoliates by expanding at right angles to the cleavage into long wormlike pieces (the name vermiculite is from the Latin veamiculari, to breed worms). This important characteristic of expansion is believed to be a mechanical separation of the layers when the contained water is converted into steam. Warping of the unit layers may also contribute to the expansion. The increase in bulk volume of commercially prepared material is 8 to 12 times but individual flakes may increase in size more than this. Pure vermiculite is a distinct mineral and has the structural formula (OH), (Mg,Fe)3 (Si,Al,Fe)4 010.4H20. It rarely occurs in this pure form, but generally as a mixed mineral of varying structure. One explanation is that the mixed material is composed of unit layers of inter-stratified pure vermiculite and biotite. The essential difference between the two is that unit cell structure of vermiculite contains a layer of water molecules whereas the biotite cell contains potassium instead of the water. The water content of the mixed vermiculite is less than that of pure vermiculite but more than that of biotite. Pure biotite does not expand when heated. If the proportion of biotite layers in a vermiculite is too high it will adversely affect the degree of exfoliation. Within a given deposit, the great mass of material may approach a definite com-position with local areas of greater biotite content. It is not uncommon to find also small pockets of pure biotite but these are generally segre-

Jan 1, 1949

By M. J. McPherson, R. Venkataramani

R. Venkataramani (Assistant Professor of Mining Engineering, Dept. of Mining, The Pennsylvania State University, University Park, Pa.)-Y. J. Wang and L. W. Saperstein are to be congratulated for their paper on the computer solution of ventilation problems. The limitations on the problem size to be solved by the program (Appendix II) has been outlined in the paper. I would like to add the following additional limitations of this computer program: The dimensions of the variable J1and J2 should be changed to J, (550) and J2 (550) to handle problems containing more than 400 branches, and up to 550 branches. If there are a large number of branches common to the various meshes, another limitation on the problem size will be the dimension of the variable NA. While a higher-order polynomial fitting for the fan characteristic data points is more rigorous, a quadratic relation, if linear interpolation between the points is inadequate, will result in saving computing time without much loss of accuracy. Of course, this can be handled by minor modifications to the existing polynomial fitting routine in the program. M. J. McPherson (Dept. of Mining Engineering, University of Nottingham, Nottingham, England)-The

Jan 1, 1972

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who registered at Institute headquarters during December: William M. Peschel, Bradford, Mass. Samuel T. Wellman, Cleveland, Ohio. Herbert B. Cox, Boston, Mass. Samuel S. Wyer, Columbus, Ohio. C. Q. Schlereth, Mexico, D. F. H. H. Stoek, Urbana, Ill. H. W. Caldwell, Oxford, N. C. E. Harms, Torreon, Mexico. Charles E. Schwarz, St. Louis, Mo. G. A. Roush, So. Bethlehem, Pa. Dwight Furniss, Guanajuato, Mex. M. K. Rodgers, Los Angeles, Cal. F. W. DeWolf, Urbana, Ill.

Jan 1, 1914

By William B. Plank

Mineral engineering student enrollment in U. S. and Canadian schools for 1955-1956 is 11,408, an increase of 11 pct more than last year. The undergraduate and graduate engineering students in both countries number 251,765, or 13 pct more than last year. These figures have been released by the American Society for Engineering Education. The largest increase in the undergraduate mineral engineering group in the U. S. is in ceramic engineering, with 676 students, or 31 pct more than last year. The next largest increase is in mining which shows a gain of 13.5 pct, compared with a gain of 13.1 pct in the total undergraduate enrollment in all engineering schools approved by the Engineers' Council for Professional Development. This figure is 190,355, which approaches the prewar figure. Metallurgical undergraduates increased 13 pct; geological, 5 pct; and petroleum, 2.5 pct. This year the figures for geophysics are combined with those for geological engineering, making a total of 1610 undergraduates, of which the geophysicists comprise about one seventh.

Apr 1, 1956

By Elmer A. Jones

Development work in mines of St. Joseph Lead Co., Southeast Missouri, using trackless loading equipment shows definite advantages: Speed of cleaning, ability to work on steep grades and sharp crosscuts, good later tracking conditions, and possibility of wasting rock in old abandoned stopes.

Jan 6, 1950

Jan 1, 1912

By A. L. Slaughter

The Homestake mine, located in western South Dakota, was discovered in 1876. The first reported production was in I 878. Total production through 1965 is 6,554,249 troy ounces of silver and 27,961,276 troy ounces of gold, worth $987,000,000 at present prices. Precambrian sedimentary formations at Lead total 20,000 feet. The Poorman Formation, the oldest, is chiefly ankerite carbonate. The Homestake Formation is iron-magnesium carbonate. The younger formations are argillaceous with some quartzites. The Cambrian Deadwood Formation unconformably overlies the Precambrian. All are cut by Tertiary intrusives. Sideroplesite schist of the Homestake Formation was converted to cummingtonite schist in the zones of higher-grade metamorphism. The Precambrian rocks show the effects of extreme isoclinal folding. A second stage of folding ( cross folds) may have been caused by the Tertiary intrusives. All folds plunge to the southeast. The Homestake ore bodies are pipe-like replacements of the Homestake Formation in zones of cross folding. It is believed that dilatation of the schists has increased permeability in these zones. Chloritization of the schists is the most widespread effect of the mineralization which is divided into four stages. Principal minerals of the first stage are quartz, chlorite, and arsenopyrite; in the second stage, quartz, ankerite, and pyrrhotite. In the third stage only pyrrhotite was deposited. The fourth stage followed the intrusions of Tertiary dikes and deposited mostly pyrite and calcite. Gold accompanies all stages and is always the last mineral to be deposited. It is most closely associated with arsenopyrite of the first stage but can be interpreted as having been deposited during the fourth stage and superimposed on the products of the earlier stages.

Jan 1, 1968

By Craig E. Saporito

INTRODUCTION Freeport-McMoRan Inc. has been very active recently with two major discoveries and its restructuring activities. This paper describes Freeport-McMoRan's businesses, the two major mineral discoveries, and exciting opportunities within the oil and gas operations. BUSINESS ACTIVITIES Freeport-McMoRan is the largest and one of the lowest cost fully integrated U.S. phosphate fertilizer producers. It is the second largest domestic Frasch sulphur producer. Freeport- McMoRan will become the largest domestic producer of Frasch sulphur when its Main Pass Block 299 sulphur deposit reaches full production in 1993. Furthermore, it is the largest transporter of sulphur produced by others. Its oil and gas activities rank among the largest U.S. independents in terms of production and proved reserves. The copper/gold operations in Indonesia are among the world's lowest cost. When expansion operations reach full capacity levels in 1992, the Indonesian copper/gold complex will be the fifth largest copper operation in the world. Operations are divided into three business segments that include: 1. Agricultural minerals, incorporating sulphur, phosphate rock and phosphate fertilizer activities; 2. Energy, including oil and gas activities; and 3. Metals, incorporating copper, gold and silver operations in Indonesia. In early 1989, Freeport-McMoRan announced the discovery of two world-class ore bodies; a sulphur deposit off the coast of Louisiana on Main Pass Block 299, and a copper/gold deposit -- the Grasberg in Indonesia -- approximately two miles away from the existing Ertsberg East operations. As a result of these major discoveries, Freeport- McMoRan decided to carry out a restructuring program. Its purpose was to sell $1.2 to $1.5 billion of non-strategic assets. Debt levels and associated interest expenses will be significantly reduced, and general and administrative expenses will be reduced, which will place Freeport- McMoRan in an excellent position to fund the development of the Main Pass Block 299 sulphur discovery, the Grasberg discovery, and oil and gas discoveries. This restructuring program also will allow Freeport-McMoRan to achieve the greatest future value for shareholders by focusing on its principal businesses (Figure 1). Strategic Restructuring • Sell $1.2 - $1.5 Billion Of Non-Strategic Assets • Significantly Reduce Debt • Significantly Reduce G&A • Fund Development Of Main Pass & Grasberg • Stronger Company; Positioned For Future Growth • Focus Is On Principal Businesses: - Sulphur/Phosphate Fertilizers - Indonesian Copper/Gold - Oil And Natural Gas Figure 1 - Strategic Restructuring AGRICULTURAL MINERALS Main Pass Block 299 Discovery The Main Pass Block 299 discovery has a proven reserve of 67 million long tons of recoverable sulphur. This is the largest known Frasch sulphur deposit in North America. The discovery increased Freeport-McMoRan's sulphur reserves more than five-fold, and is synergistic with the company's phosphate fertilizer assets. The

Jan 1, 1990

AARONS, J. BOYD, Major. AGNEW, FRANK VANS. ALLEN, HERMAN H., Private, D Co., 8th Reserve -Engineers. AMBLER, HARRY A., Second Training Camp, Ft. Sheridan, Ill. BAINS, THOMAS M., JR., Major, Engineer Officers' Reserve Corps. BANKS, H. R., Lieutenant, Canadian Engineers, B. E. F. BARBOUR, PERCY E., Deputy Supt. (Captain), New York State Troopers; Captain, 22c1 Regiment, N. Y. N. G. BARLING, H. B., 1st Lieutenant, Engineer Officers' Reserve Corps. BARRETT, LESLIE P., Lieutenant, A. E. F., France. (Unattached.) BENSEL, J. A., Major, Engineers' Reserve Corps. BIGELOW, BRAXTON, Royal Engineers, B. E. F. BLOOMFIELD, E. C., Lieutenant. BORROW, F. K. BOWLES, MARTIN F., 2d Lieutenant of Infantry, Camp Funston, Kans.

Jan 10, 1917

By N. Arbiter, C. C. Harris

Analysis of ball and pulp flow in ball mills indicates that three factors may become critical with increasing mill diameters: ball size, fraction critical speed, and average pulp flow velocities. Ball diameters may need to be decreased and fraction critical speeds increased with ores which show decreased breakage rate coefficients above 1.2 mm (14 mesh). With 5.5-m (18 ft) and larger mills at higher circulating loads, pulp flow velocities may become capacity limiting and also may limit increases in ball mill diameters.

Jan 1, 1985

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 James Howe

EVERY engineer and user of wire rope is desirous of information that will enable him to determine whether the performance of any particular piece of rope is satisfactory, and what conditions can be changed so as to increase the life of a rope. In most cases, it is far from easy to analyze the conditions of service and tell which is the greatest factor in determining the life of wire rope. If we start on a layout for an entirely new rope system, the task of making conditions satisfactory is simplified so far as the engineering details are concerned; but if the plant requiring wire rope is in operation, any change is likely to involve the expenditure of consider-, able money to replace and change over machinery that must be kept in constant operation, because a large monetary loss will result from a shutdown for even a few days. Often wire rope is kept operating under bad conditions, as the user thinks that it is cheaper and quicker to replace the rope than to make alterations in the hoisting machinery. A typical case is a metal mine operating in what is now almost the center of a large mining city, where it owns a few acres of mineral rights. It was expected that the shaft would go to a depth of 1000 ft. (305 m.), so a moderate sized rope, about 1 ¼ in. (31.7 mm.), was used on a 6-ft. drum with a 7-ft. head-frame sheave and rather short lead from drum to head sheave. This mine has gone deeper each year until, it is now 2500 ft. deep and the rope speed has been increased from 1500 ft. per min. to over 3000 ft. The original rope just filled the drum in one layer, now it overwinds three layers. The original ropes were probably 6 X 19 crucible steel and lasted from 12 to 18 mo.; now, the highest grade plow steel is used, yet the average service is only about 6 mo. The cause is not hard to find. If the engineers had known at the outset what would be done with this hoist, the design would have been very different. Conditions at this mine, from a wire rope standpoint, have gradually become worse and it is difficult to see how rope service on this hoist can be com-pared with the service of previous years with any fairness to the wire-

Jan 2, 1922

By D. H. Polonis, M. B. Kasen

AN unusual thermal etching phenomenon has been observed on the surface of a Cu-Si alloy. The observations were made during studies of vacancy condensation pit formation which were reported in previous papers.1,2 Figs. 1 and 2 are photomicrographs of the surface of a Cu-4.8 pct Si alloy after heating in vacuo (3 x X mm Hg) to 525°C and subsequently holding at that temperature for 16 hr in an impure (air-contaminated) argon atmosphere. Under these conditions preferential removal of silicon from the matrix by oxidation results in a surface which is entirely a phase overlying an a plus y structure. The light areas of Fig. 1 are regions in which very little thermal etching has occurred, while the majority of the surface has experienced severe etching. Similar regions in Fig. 2 are seen as plateaus above contours produced by net transfer of material from the specimen surface. Twin boundaries are also visible in Fig. 2. The difference in matrix mi-crostructure between Figs. l and 2 reflects the par- ticular orientation of low-index planes with respect to the surface of observation. Thermal etching contours of this type have been studied in detail by Hondros and Moore Both of the photomicrographs show that one or more dark spots are located approximately at the center of every protected area; where two spots are in close proximity, the protected areas have merged. The microstructures indicate that the anomalous resistance to thermal etching is related to the presence of these spots. Williams and Hayfield have shown that local regions of unusually high oxidation resistance can be caused by a surface monolayer of atoms with a work function higher than that of the base material. The result is an inhibition of the rate of electron removal from the base material and a decrease in the oxidation rate. The source of the protected layer may be either surface diffusion from contaminants on the specimen surface or pipe diffusion of solute atoms followed by migration across the surface. In the latter case the driving force is a difference in chemical potential resulting in a Gibbs adsorption phenomenon. In the present case, chemical polishing of the specimen surface precluded contaminants of a strictly surface nature. Consequently, diffusion of impurity atoms from within the lattice appears to be the most tenable explanation of the observed phenomena. The authors propose that the structures of Figs. 1 and 2 reflect the diffusion of impurity atoms along extended dislocations within the individual a phase grains prior to surface oxidation. The central spots within the protected regions are seen as sites of dislocation emergence which have become locally decorated with oxide in the manner discussed in Ref. 1. Williams and Hayfield observed protected regions adjacent to the grain boundaries of iron-contaminated copper which they attributed to the segregation of iron to the grain boundaries coupled with high dif-fusivity along the complex dislocation array at such boundaries. No evidence of such grain boundary protection was observed in the Cu-Si alloy; this

Jan 1, 1964

By J. H. Smith, H. W. Paxton

X HE recent investigation of Butler, McCabe, and paxton' on the vapor pressure of manganese gas in equilibrium with Mn-Fe alloys has been extended to include the iron-rich solutions and alloys in the two phase equilibrium region. The study of the phase equilibrium by Kurnakov and Troneva2 and the extensive reviews of the Mn-Fe system by Hansen,3 and Hellawe114 are not in agreement with regard to the location and extent of the equilibrium between the solid phases of fcc y and complex P in the temperature range above the eutectoid temperature of approximately 975Kwhere 0 decomposes to y and bcc a. An evaluation of the existing equilibrium data is confronted with the conflicting results presented by various investigators who used techniques requiring a quenching treatment to retain the high-temperature equilibrium or encountered temperature hysteresis during thermal analyses. The difficulty of suppressing the transformation of the manganese-rich concentrations of the y-solid solution during quenching has been well etablished.' To avoid this uncertainty the phase equilibrium was investigated at temperature by measuring the partial pressure of manganese gas in equilibrium

Jan 1, 1962

By N. A. Elmslie

This subject covers much ground, therefore it must be treated in a general way rather than in detail in this paper. Personnel To approach the measure of a mine, it is, of course, essential that the personnel be measured, and this measuring must be done in a circumspect manner and conclusions must be reached slowly. There may be one unit in the personnel of an organization that may be out of step with the remainder of the organization, not always because of lack of ability, but because of misplacement or lack of proper measurement of his capabilities. Too much time can scarcely be spent in the study or measure of the personnel ; in fact, a manager or a superintendent of a mine never completes his work along this line. Mine or Plant Just as no two men are alike, so no two mines or plants are alike; and yet there are many similarities. Find out what the similarities are, and this will help to make clear the dissimilarities. Try to visualize details of the difficulties, not because you will have to deal with them yourself, but to consider them in later studies of general problems. To outline all the steps to be taken in familiarizing oneself with a plant or operation would be impossible, but the following points may be of interest in any investigation. The study of a mine is generally made backwards-—that is to say, one sees the finished product first-—-but this is immaterial, because each step must be considered separately in any event. As a rule, there are certain heads under which the different features of mining can be placed, as follows: Ventilation.—Ventilation is usually the most important item in power cost and safety, especially in gassy mines. Quantity of air, water gage and power consumption, and finally analysis of the return air in full return and separate splits should be considered. Type of fan and type of power unit should enter into this study because it is important to view expenditures which are going on 24 hr. a day and 36.5 days in the

Jan 1, 1931

By Nathaniel Arbiter, Arthur F. Taggart

THE chemical reaction occurring in collection of nonmetallic minerals with amine-type collectors was early postulated by students of flotation phenomena to be metathesis between the mineral and the collector, involving exchange between the amine-bearing (aminium) ion and the cation of the mineral, and formation at the mineral surface of an oriented film of the amine salt of the mineral anion. Qualitative evidence of exchange has been obtained on several occasions at Columbia. Thus 1000 c.c. of a solution containing 495 mg. of laurylamine hydrochloride was shaken 17 min. with 100 grams of barite and ground in a porcelain mill to pass a 200-mesh screen; the mixture was then set aside for 48 hr. Filtrate therefrom analyzed 476 mg. per liter of laurylamine hydrochloride. There was no substantial loss of chloride ion (78.4 mg. per liter in the original; 74 in the filtrate). No successful analyses were concluded for barium ion. Earlier, confessedly rough work with scheelite indicated a solution gain in Ca++ equivalent to about one-half the aminium ion lost. Real quantitative proof of the exchange, in the form of an established stoichiometric balance, is unknown to the authors. The data of the present paper, however, obtained from experiments designed on the basis of the exchange hypothesis, constitute strong evidence of its truth, and at the same time point the way to economic utilization of the expensive nitrogen-bearing collectors in concentration of the low-priced nonmetallic minerals. The basic postulate underlying the experiments performed was that, if the collecting reaction is of the type [R+ + Y- + MX =± RX + M+ + Y¬] where R = aminium ion, Y = the anion of the amine salt, and M and X are, respectively, the cation and anion of the mineral, the reaction should obey qualitatively the implications of the massaction and solubility-product laws. This is to say that coating and collection should be aided by the addition to the solution of either ion (R+ or X-) of the collector-coating compound, and hindered by the addition of either of the ions M+ or Y-. Experimental work comprised determination of (1) the relative solubilities of the laurylammonium salts of a variety of nonmetallic-mineral anions; and (2) the contact angles1 of various minerals in solutions containing different concentrations of the postulated controlling ions. Semiquantitative flotation tests were run with barite as checks on the diagnostic character of the contact angles. The amine

Jan 1, 1944