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By John V. Beall

Never having done it before, it took us all day and until 11 at night to select and pack for a four-day back- pack trip up Lake Chelan last month. When we were through, we couldn't lift our own pack and Sylvia's, OUT spouse's, we barely managed to budge. Nevertheless, the next morning we were at the dock to board the Laldy of the Lake for the 3 ½ -hr boat trip to Lucerne. Our dress and accouterments creating the appearance of a veritable expedition into the wilderness made a sharp contrast with our fellow passengers, a senior citizens tour group from Spokane. We had come out to Seattle for the SME Fall Meeting and were taking advantage of the occasion for a vacation trip back to Lucerne and Holden where we had lived briefly 25-years ago, and a backpack trip up Railroad Creek from Holden to the Glacier Peak country, weather permitting. No matter what you say, weather is important, and this is one of the ingredients that went into making the SME Fall Meeting and Exhibit in Seattle, September 22-24, a thoroughly delightful experience for the 700 plus persons who attended. Seattle is a beautiful city, but with late September sunshine, which we experienced, it is the best. The second ingredient, is a swinging host committee. Under the leadership of Don Anderson and Tom Van Zandt, co-chairmen, and Mrs. Cecilia Reed, Ladies Program, superb hospitality and fine arrangements were blended. Earl Beistline, from Fairbanks, organized a two-day short course on arctic operations which preceded the meeting and drew an attendance of 44. Dick Robbins, in charge of arrangements, provided Masters-at- arms for technical sessions and a presentation of the colors by the U.S. Coast Guard at the Welcoming Luncheon. Eric Cheney's field trips ranged far and wide with events both before and after the meeting. David (Jeff) Kroft, capably managed audio-visual operations with a group of students from the University of Washington. Charles Hochmuth worked long, hard and effectively before and during the meet- ing on finances. Hank Reed, managed an authentic three-ring circus as Entertainment Chairman. His activities covered two cocktail receptions for all registrants and a dinner-dance. Dolph Campbell and Joe Hackbarth provided publicity by press and TV (see p. 37-40). SME's meetings have certain characteristics and possibly not all of these are known to everyone. The first of these is the deliberate involvement of the AIME Section in the area of the meeting. Most trade shows and conventions are run 100% by a professional staff and although SME staff could also do this, it has been our experience that a more friendly and better meeting results when the local members apply their talents. Actually SME only considers a site for a meeting after it has received an invitation from a Section. The knowledge of local conditions which Section committeemen bring to a meeting is of great value.

Jan 1, 1971

By H. W. Mead, C. E. Birchenall

SELF-DIFFUSION of iron in austenite is a process which may play a significant role in some of the practically important reactions which occur in solid irons and steels. It also provides a system in which the interaction of vacancies on substitutional sites and atoms in interstitial positions may be investigated. For both purposes, accurate values of the diffusivities are required. Two sets of previous measurements exist, each containing features which require checking. In the course of an investigation to determine the rate of diffusion of iron in certain steels, Garwick and Rosenqvist' measured the self-diffusion coefficient of iron in a 0.10 pct* C steel and obtained a dicated that while at lower temperatures D increased with increasing carbon content, at the higher temperatures it first increased and then decreased. At the same time the activation energy decreased linearly from a value of 69,000 cal per g-atom for pure iron to 33,000 cal per g-atom at 1.06 pct C. This rapid decrease in activation energy implies that iron at higher temperatures within the austenite range would diffuse more slowly in high carbon steels than in steels of lower carbon content. Experimental Procedure The radioactive iron used in this work was obtained from Oak Ridge National Laboratory. The unit consisted of about 1 microcurie each of Fe7 and Fe It was allowed to decay for two years. At the end of this time most of the Fe with a half-life of 46.3 days, had decayed, while most of the original Fe(half-life 2.91 years) still remained. The iron as chloride was extracted into an ether layer, using the method of Ashley and M~rray. After evaporation of the ether the iron chloride was dissolved in 250 ml of aqueous solution containing 2.4 gpl Fe. The compositions of the steels used are listed in Table I. Disks of ¾ in. diam and about ¼ in. thick were machined from these steels for use in diffusion couples. The disks were surface ground on both sides to ensure parallel opposite faces. One face of each disk was polished through 000 emery paper. Half of the prepared disks were plated with radioactive iron. For this, 1 ml of the radioactive iron

Jan 1, 1957

By J. A. Ede

The object of the writer is to call attention to a rather unique aggregation of economic products distributed over a line of succeeding formations about 3 mi. long, to be seen within a few miles of La Salle, Ill. Fig. 1 is an ideal section of the stratification exposed and exploited along a distance of 3 1/5 mi. in a southwesterly direction from the quarry of the Utica Hydraulic Cement Co. located near the historic site of Kaskaskia village to the Oglesby shaft at Oglesby. No attempt has been made to cover the whole field, special mention only being made (with the exception of two places) of the operations found along the course or parallel to the direction assumed in the ideal section. I have used Fig. 2, after J. R. Bent and De Witt Kelly, to locate the relation of the La Salle anticline to the coal mines of this district and to show the operation of No. 1 and 3 mincs of the Illinois Zinc Co. Anticline and the Rock Formations Owing to the structural deformation between La Salle and Utica, the older rocks of the state are exposed to the surface along the northern embankment and the bottoms of the Illinois River valley near the latter place. At; the Illinois Zinc Co. works, Sec. 16, Tp. 33, R 1, a well for water mas sunk 1828 ft. and samples taken every 10 ft. of the ground penetrated; duplicates were sent to Mr. Cady of the Illinois Geological Survey. A general compilation or synopsis study of this section is here presented. As the well is over 1 mi. west of the Western limb of the anticline, the section affords some reliable data. These samples were studied and interpreted by H. M. DuBois as Lower Magnesian, and by G. H. Cady as the Lower Magnesian. The results are given in Fig. 3. The most interesting geological feature of this district is the La Salle anticline. In 1865, Leo les Quereux, looking at Split Rock, asked how it happened that the upper coal measures overlie strata of the Lower Silurian and what has become of the formations which are generally found intermediate—the Upper Silurian, the Devonian and sub-carboniferous, and the lower member of the coal measures?

Jan 1, 1920

MORE than 5000 miners and suppliers descended upon Denver to make the American Mining Congress' four-day metal mining show one of the most extravagant equipment displays ever assembled in one place at one time. The most recent developments in equipment for mining, milling, and processing ore were shown by the 146 exhibitors at Denver's new City Auditorium which covers 57,000 sq ft of floor space. Other displays were placed in the open air opposite the auditorium site. Registration desks were opened Sunday, Sept. 21. A field trip to the Colorado School of Mines at Golden was the featured activity of the day. Official opening of the show took place on Monday, and presided over by Howard I. Young, president of American Zinc, Lead & Smelting Co.; Otto Herres, vice president, Combined Metals Reduction Co.; William J. Coulter, vice president, Climax Molybdenum Co.; Charles B. Stainback, Westinghouse Electric Corp.; and Merrill E. Shoup, president, Golden Cycle Corp. Convention welcoming addresses were delivered by a representative of Mayor James Q. Newton, of Denver, and Gov. Daniel V. Thorton of Colorado. Following the formal opening ceremonies a round table discussion dealt with the "Paley Commission Report" formally called Resources for Freedom. Participating in the panel were: Arthur H. Bunker and George R. Brown, members of the Paley commission; H. I. Young, president of the American Mining Congress; Horace M. Albright, president of U. S. Potash Co.; Evan Just, vice president, Cyprus Mines Corp.; Donald H. McLaughlin, president, Homestake Mining Co.; E. H. Snyder, president Combined Metals Reduction Co.; Simon D. Strauss, vice president, American Smelting & Refining Co.; Sen. H. C. Dworshak (R.-Idaho) ; Ira B. Joralemon, consulting engineer; Jess Larson, De fense Materials Procurement Agency; and Andrew Fletcher, president of St. Joseph Lead Co. The panel discussed the report for six hours, adding a great deal of information to the already voluminous amount which has been gathered concerning it. Three objections to the report frequently mentioned were: 1-the multilateral contract; 2-international buffer stocks; 3-international buffer stocks combined with limited quota arrangements. Points on which the panel commended the report were its recommendations for acceleration of topographic and geologic mapping of the United States and Alaska; recognition of the principle of percentage depletion for metals and minerals; and advocation of removal of the present limitations on the expensing of exploration costs applicable to minerals. Technical sessions were held throughout the four days of the meeting. Included in the program were: Progress in Mechanication; Small Mines; Public Lands; Open Pit Mining; Manpower-Labor Relations; Shaft Sinking; Roof Support; Taxation, Gold, Silver and Monetary Policy; Advances in Mill Practices; Special Conference on Strategic Materials; Uranium Mining-Atomic Energy; Prospecting and Exploration; New Metallurgical Processes; and Rock Breaking. About 45 papers and several panels were presented during technical sessions. Formal and informal social functions consumed the remaining time of the convention. Three locations were needed to handle the huge throng attending the Mining Jamboree Monday evening. The only other sponsored social function took place Thursday evening. A great many informal gatherings, chiefly convivial, were held in manufacturers' courtesy rooms-called wet stopes. Field trips included Cripple Creek, Pueblo, Climax -Leadville-Gilman, Colorado Plateau-Grand

Jan 1, 1952

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 C. S. Yust, C. S. Morgan

ThIS note reports the observation of masses of dislocation etch pits around the weld necks of small single-crystal particles of calcium fluoride sintered to a cleaved face of a larger CaFz crystal. Crystal particles in the -50 +I00 mesh size range were placed on freshly cleaved CaFz surfaces and heated at 1250°C for 30 min in a tantalum container in an argon atmosphere. The sintered specimens were then etched at room temperature for 40 to 50 min in a 2 pct sulfamic acid solution which is a selective etch for dislocations in caF2.' Figs. 1 through 3 show the masses of dislocation etch pits observed around weld necks after etching. In some cases, particles were gone after removal of the specimens from the furnace although weld necks were readily visible. In other instances, no etch pits formed around a weld neck. A possible cause of concentrations of dislocations on the crystal surface is mechanical deformation of the base crystal when particles are dropped on it. If such a deformation does occur, it would be much smaller than that caused by the light punching of a crystal with a sharp instrument which results in large concentrations of etch pits. However, crystals deformed by punching with the sharp instrument and annealed at the conditions of these experiments (1250°C for 30 min) before etching showed no concentrations of dislocation etch pits. It is obvious that dislocations from the much smaller deformations, possibly created when particles are placed on the surface, would also anneal out. Etching of large crystals which had particles placed on them in the usual manner but which were not heated showed no dislocation concentrations such as shown in Fig. 1. The magnitude of dislocation etch-pit concentrations did not vary with extensive variation of the cooling rate. The appearance of many of the etch-pit clusters is typical of a well-annealed condition, indicating that the dislocation concentrations formed before the specimen temperature was lowered. Therefore, it is evident that thermal stresses in the neck area did not create the deformation indicated by the presence of the dislocations. The possibility exists that the etch-pit concentrations at places where particles had been removed may be the result of deformation accompanying the fracture of the sintered bond. That this is not so was demonstrated by breaking off particles around which no etch pits occurred. Re-etching never resulted in the large concentrations observed at sintering sites. The stress available to effect material movement during sintering of two particles will depend on the geometry at the contact point but can easily exceed the macroscopic yield stress in CaFz systems. It appears that the plastic deformation observed results from sintering or simply from the weight of the small particles. It has been previously argued that plastic flow makes an important contribution to the initial densification of oxides having the fluorite crystal structure.2p3 If plastic deformation occurs, it would begin as soon as the temperature is sufficiently high

Jan 1, 1967

By Jon J. Connor, Richard J. Ebens

The trace element geochemistry of the cherty clay-rich carbonate residuum cover in much of southern Missouri and adjacent parts of Arkansas was investigated during the earl 1970's as part of a statewide geochemical survey of Missouri.1-8 The study was environmentally oriented and focused on the character of the "natural" geochemical environment of the state. A great deal of effort was made to collect samples that would represent the geochemical variability of the near-surface environment in an unbiased way. In general, this was accomplished by use of randomization procedures in both collection and analysis. Most of the sampling sites were selected randomly to prevent personal bias from entering into sample selection. In the laboratory, samples were analyzed in a randomized sequence to circumvent the effects of any systematic bias that may have entered into the laboratory procedures. Several residuum samples contained 1000 parts per million (ppm) or more of lead, zinc, and barium. All these samples were collected in Washington County in or near the barite district. The frequency distributions shown in [Fig. 1] indicate just how unusual the residuum in Washington County is with regard to these three metals and copper. The shaded parts of the histograms represent the samples from Washington County. The histograms are based on analyses of 141 samples from 38 localities scattered over the subcrop of the Cambrian and Ordovician formations of southern Missouri and northern Arkansas. Eight localities were selected randomly from over each of four bedrock units-Bonneterre dolomite; Potosi and Erninence dolomites; Roubidoux formation; and the Jefferson City, Powell, and Cotter dolomites. Six localities were selected randomly from over the Gasconade dolomite. The geochemical "background" for these elements in residuum is defined by samples from outside of Washington County (unshaded part of the histogram); lognormal distribution curves have been fitted to the corresponding parts of each histogram. Clearly, these lognormal models (curves) describe well the background distributions of zinc, barium, and copper. The background histogram of lead concentrations is notably skewed to the right compared to the model. Lognormal distribution curves were also fitted to the data on lead, copper, and zinc in the residuum of Washington County. No model was fitted for barium in Washington County because of the distinct bimodality in the data. All samples containing more than 1000 ppm were collected in the barite mining district and obviously reflect the elevated levels of barium in the district. The frequency distributions for Washington County are clearly anomalous with respect to the background data, those for lead, zinc, and barium being exceptionally so. The models for anomalous lead, zinc, and copper seem to fit reasonably well, although the scatters in the lead and zinc anomalies are considerably larger than the scatters in the corresponding background data. The copper anomaly, although probably real, is greatly subdued compared to that of lead and zinc. Also, it has a scatter similar to that of the copper background, rather than being enhanced like the scatters of the lead and zinc anomalies. On the basis of techniques described by Miesch,4 the chemical abundance of copper, lead, and zinc in residuum in

Jan 1, 1980

By E. R. Johnson

THE copper concentrator of the Braden Copper Co. is at Sewell, Chile, on the western flank of the main Cordillera of the Andes, at an air distance of approximately 50 miles southeast of Santiago, the capital of Chile. The region is mountainous and space is at a premium because of the rough terrain and the danger of snowslides. The ore, a porphyry copper, is mined by a block-caving method in the El Teniente mine. It is hauled to the crushing plant, a distance of 2.6 miles, through a tunnel because of the severe climatic conditions. The usual large, coarsely set, primary reduction machines found in many ore-treating plants are not required because of the mining method employed and the limiting 12-in. spacing of the grizzlies at the head of each ore pass in the mine. It is the purpose of this paper to describe the numerous improvements made in the crushing section of this large flotation concentrator during the past 15 years to increase the efficiency of the plant and to raise the daily output from around 20,000 to 30,000 tons. The reader should keep in mind that all changes were made within the existing building because of the limited space and the high cost of the heavy mill construction required to withstand the snow loads. The present plant, as well as the former, operates on a 24-hr, 7 days a week basis. FORMER PLANT The crushing plant commenced operations at its present site in 1921, the main equipment being No. 7 1/2 gyratories, followed by 48-in. horizontal Symons disk crushers. Fines were removed by 1-in. stationary grizzlies ahead of each unit. In 1924 a third stage of crushing was provided by the addition of 55 1/2-in. rolls in open circuit. During 1925, the Symons disks were replaced by 73 1/2-in. rolls. All the rolls were changed to closed circuit, with elevators and screens to give a final product of 9 pct plus 3-mesh. The flowsheet of a typical crushing section of this period is shown in Fig I. The ore was withdrawn from a common bin serving the five crushing sections in the plant by means of any number up to six 36-in. wide-apron feeders, which discharged onto a common conveyor belt. This conveyor was equipped with a magnetic head pulley and the crusher attendant was stationed near the discharge end to pick out pieces of mine timber that might be in the ore. The ore was discharged over a 1 3/4-in. spaced bar grizzly and the oversize of this grizzly was crushed by a No. 7 1/2 McCully gyratory crusher set at 1 3/4-in. opening on the closed side. The grizzly undersize joined the gyratory discharge and was conveyed to a set of 73 1/2 by 20-in. Garfield rolls set at I in. These rolls operated in closed circuit with a bucket elevator and two vibrating screens placed in parallel.

Jan 1, 1947

By S. F. Reiter, You-Chao Liu, W. R. Hibbard

Cyril Stanley Smith in his classic 1948 Institute of Metals Lecture&apos; noted in the case of annealing twins that: "It is well known that approximately the same number of twins per grain and the same general geometry are maintained in large grains as in small ones, a fact that certainly suggests a mechanism such as the above where boundaries and twins grow proportionately together. If this view is correct, a spherical grain should have no mechanism for keeping its twins." Such a constancy of twins per grain would be of particular interest as a tool for the study of the origin of annealing twins. It has been proposed by Mathewson2 and later by Barrett3 that in face-centered cubic metals slip occurs in the {111} Plane by <112> shears which combine in pairs to produce the macroscopically observed <110> movement. This proposal is schematically inviting since <112> slip permits the atoms of one plane to move along the interatomic valleys of its neighbor rather than up the hills across the atom sites. There is strong experimental evidence? that annealing twins result from the growth of nuclei in the form of "twin faults" produced by single <112> shears. It is possible that more twin faults would form at low deformation temperatures than at high ones, because the more rigid lattice may increase the tendency to "freeze" the twin faults and prevent their dissipation in slip. This is suggested by (1) the greater resistance to slip at low temperatures and (2) greater tendency toward mechanical type twinning at low temperatures (a summary of these factors is presented by Seigle and Brick5). These considerations would suggest the following: a. Constant twin/grain ratio for specimens deformed constant amounts at a constant temperature, but annealed at various temperatures above the recrystalliza-tion temperature. b. Larger twin/grain ratios for re-crystallized specimens previously deformed constant amounts at lower temperatures. The purpose of this investigation is to test these considerations. One half in. rods of phosphorous deoxidized electrolytic copper and 70-30 alpha brass (68.36 pct Cu, 0.005 pct Pb, 0.01 pct Fe, 31.62 pct Zn remainder) were rolled to a thickness of 0.350 in., milled to specimens 0.350 X 0.437 X 2 in., and annealed at 700°C to an average grain size of 0.065 and 0.090 mm, respectively. These specimens of each metal were then rolled 50 pct reduction in thickness and annealed one hour under conditions which were all combinations of the following: Rolling Annealing Temperatures. Temperatures. °C °C -70 400 25 500 200 600 Standard metallographic techniques&apos; were used to prepare specimens. By the method of lineal analysis7 using a minimum of ten samples of fifty grains each for each specimen, the ratios of twins* per total grains, twins per twinned grain, twin families* per total grains and twins per twin family were determined. Recrystallized grain size was determined by A.S.T.M. comparison methods.8 All observations were made on the rolling plane. The results are tabulated in Table 1.

Jan 1, 1950

By R. E. Ogilvie, N. L. Peterson

DURING the past few years there has been considerable effort devoted to the understanding of radiation effects on materials. The concept of the Frenkel defect and other lattice defects suggests that radiation may alter the rate of many metallurgical phenomena, especially those which are diffusion controlled. In 1953 R. R. Coltman and T. H. ~lewitt&apos; found an appreciable effect on the ordering rate of Cu,Au due to fast neutron bombardment. Since then several rather comprehensive theories have been proposed on radiation enhanced diffusion in solids.2"4 If the energy of the radiation is above the threshold energy for the removal of atoms from their lattice sites, Frenkel defects will be produced. These defects can be produced uniformly throughout a relatively thick specimen by high-energy X-rays permitting bulk property studies without the limitation of sample dimensions. In this work high-purity arsenic containing 30 ppm of impurities was allowed to diffuse from the gase- ous phase at 700°C into single crystals of p-type germanium containing 0.1 ppm of indium. As the arsenic diffuses into the P-type germanium, an n-type layer will form in the diffusion zone. At the p-n junction the concentration ratio of the arsenic to the indium is constant. Experimental Procedures—The germanium specimens, 10 mm by 10 mm by 5 mm, were polished and etched to a mirror finish. The specimens were then sealed off in a vycor glass capsule at 3 x 10"5 mm Hg pressure with a sufficient amount of arsenic powder to produce a one-half atm pressure of arsenic at 700°C. Specimens were annealed at 700°C without radiation. The diffusion coefficient determined from these samples agrees within 8 pct of previous work done by Fuller.&apos; Three specimens were given diffusion anneals at 700°C in a small tube furnace centered beneath the target of a 2-mev Van de Graaff generator. The specimens when in the furnace were 10 cm directly below the target of the generator. These specimens were irradiated continuously during the diffusion run with the Van de Graaff operating at 2 mev with a tube current of 225 to 250 pamp. The intensity of the x-radiation at the surface of the specimen inside the furnace was approximately 4.5 x l05 roentgens per hr. The temperature was controlled within m2°C by a chromel-alumel thermocouple throughout this work with no observed temperature change due to the radiation. By careful lapping, the samples were polished at an angle of 5 deg to the diffusion zone, giving a XI0 increase in the visible diffusion zone. The location

Jan 1, 1960

By Hugh Rose

The properties of the company lie within the Pachuca district, State of Hidalgo, Mexico, connected by three railway lines with Mexico City, 55 miles southwest, and by two lines with Vera Cruz, 250 miles southeast. The ores were formerly divided by sorting into two classes, smelting and milling, the former averaging about 2 oz. gold and 335 oz. silver, the latter 0.12 oz. gold and 23 oz. silver. The smelting ores were sold to custom plants, principally the American Smelting & Refining Co. at Aguascalientes. The milling ores were treated by the patio process at the Guadalupe Hacienda, at Pachuca. This patio was probably the largest in existence at the time and continued in active operation up to March, 1910. In January, 1910, the mines and patio were sold to English interests, represented by Camp Bird Limited. Two new companies were formed, the Compania de Santa Gertrudis, S. A., to operate the mines, and the Compania Beneficiadora de Pachuca, S. A., to build and operate a custom cyanide milling plant. (Pig. 1.) Geology The historical geology of the Pachuca district is described by Fred J. Pope as follows: 1. The most recent sedimentary rooks in the district belong to the Cretaceous period. 2. The Cretaceous rocks were penetrated by large intrusions of ande-site (referred to hereafter as primary andesite) which occur as elliptical dome-shaped masses, striking northwest-southeast. These andesite bodies are from 8 to 15 miles long and from 6 to 10 miles wide. 3. A period of erosion during which the contour of the andesite domes was changed. 4. Andesite flows (secondary andesite) which rest unconformably on the primary andesites.

Jan 1, 1917

By Robert J. Ramsey, Robert D. Jeppson

Introduction The Utah Copper Division of Kennecott Copper Corporation will present its contribution to the A. M. Gaudin Flotation Symposium in four parts. The first two segments will discuss briefly the historical development of the Utah Copper Division and describe the ore body. The third segment will review the facilities and operating procedures for the Utah Copper division&apos;s newest plant, the Bonneville Concentrator. The fourth segment describes flotation process circuitry, including molybdenite recovery procedures, at the Arthur and Magna concentrators. (The Bonneville concentrator is a crushing and grinding unit and does not have its own flotation plant). I. Historical Development Progress through change has been the key to the successful operation of the Utah Copper Division for more than 70 years. As the original low-grade copper operation, the pressures to remain competitive and profitable have dictated the timing and extent of each change. Much of the change has occurred through technological and economic advancements in the area of ore concentration. The Utah Copper Division of Kennecott Copper Corporation had its origin June 4, 1903, when the Utah Copper Company was organized. The initial mill of 300 tpd (tons per day) capacity was built at Copperton a few miles below the present Bingham Canyon mine site. From 1904 to 1910, the Copperton mill was expanded to a capacity of 1,000 tpd, and all of the known apparatus for gravity concentration were evaluated.

Jan 1, 1976

F. W. Matthiessen, who, with E. C. Hegeler, of La Salle, was one of the creators of the zinc industry in the-United States, was born in Altona, Schleswig-Holstein, Germany, Mar. 5, 1835. He was one of a family of remarkable brothers, two of whom were long absociated in this country with the sugar and glucose industry. Mr. Matthiessen was educated at Freiberg, and came to this country in 1857 with Mr. E. C. Hegeler, after having, in company with that gentleman, visited the mining districts of Germany, Belgium, and England. They first went to Friedensville, near Bethlehem, Lehigh County, Penn., wherc attempts had already been made to produce zinc from the ore deposits found in that place. The ore was a he silicate but all attempts to extract zinc from it had failed. Mr. Matthiessen and Mr. Hegclcr were successful, but declined to invest their money in the zinc industry at Bethlehem because 01 certain local conditions. Hearing of the discovery of zinc -ore in the West, they visited both Wisconsin and Missouri and thought of settling in the coal region of East St. Louis. Finally La Salle, as being near to the Wisconsin fields and having much coal, was selected ae the site of the new smelting company, and on Dec. 24, 1858, the first shovelful of dirt was turned for the buildings of the new industry. The Civil War at first interfered with the manufacture of zinc, but afterward a lively demand for the metal arose and the future success of the institution was established. A large rolling mill was added in 1866, and in 1881 the manufacture of sulfuric acid as a byproduct was begun. Mr. Matthiessen also developed the Western Clock hlanufacturing Co. of La Salle, which manufactures the Big Ben alarm clock, from a small plant having 25 men to the present large institution which employs some 2000 workers. Mr. Matthiessen&apos;s affiliations with other metal industriefi have been numerous. But the contributions of the great zinc manufacturer to the causes of philanthropy and education have made his name known throughout the country, beyond industrial circles. He has given to the city of La Salle probably a sum total of $500,000 in various benefactions. Among the objects of his philanthropy were the La Salle-Peru Township High School, which he has made a model institution of secondary education for the entire United States; also the Tri-City Hygienic Institute of La Salle, Peru, and Oglesby, Ill., which he endowed for $200,000 This Hygienic Institute, which is unique in the United States, has a traincd staff of health officers, bacteriological laboratory, medical library, infant welfare station, milk station, free dental clinic, school nurse, and isolation hospital. Mr. Matthiessen was elected mayor of the City of La Salle three times and gave generously to the municipality of which he was the head. He also saved for the people of Illinois one of the great scenic districts of the state, Deer Park, with its cafions and natural beauties, which he con-verted into a model scenic resort, and the proceeds of which he gave to the charities of the Tri-Cities in which he lived. He died on Feb. 11, 1918.

Jan 1, 1920

By J. M. W. Mackenzie

A microelectrophoresis technique has been used to measure the zeta potential of quartz over a range of pH and ferric iron concentration. The results have been discussed in terms of the adsorption of ferric cations and ferric hydroxide to the quartz surface. Possible relationships between the experimental results and the flotation of quartz have been examined. The adsorption of multivalent cations at the surface of quartz has been studied by many investigators who have used a variety of experimental techniques ranging from streaming potential 1 to radiometric2 measurements. Two possible mechanisms of cation activation of quartz have emerged from the results of these investigations viz: the adsorption of the cation to the negatively charged quartz surface, followed by adsorption of the collector anion to the adsorbed cation site, or: formation of a cation-collector complex which is then adsorbed to the quartz surface. In many natural and industrial systems one of the most prevalent activating species for quartz is ferric iron, this is especially so in the acid-circuit, anionic flotation of iron ore. The adsorption of ferric iron to the quartz surface is complicated by the ability of ferric iron to form complexes with anions, a phenomena which is of minor importance in one of the most widely studied quartz activation processes, ca ++ activation.* *The pK value for [ca(oH)+]/ [ca2+] [oh-] is 1.46 indicating that the influence of Ca (OH)+ ions will be minor in all but strongly alkaline solutions. In order to obtain a better understanding of quartz activation by ferric iron the zeta potential of quartz in the presence of ferric iron has been measured over a range of pH and ferric iron concentration. EXPERIMENTAL METHODS Materials: Selected samples of "rock clystal" quartz from New England, N.S.W., were ground in a pebble mill, washed for three hours in boiling concentrated hydrochloric acid, washed in hot chromic acid and then washed repeatedly with distilled water until the washing water gave no trace of chloride ion.

Jan 1, 1967

By H. H. Podgurski

Above 200°C the observed increase in the apparent solubility of hydrogen in low alloy steels caused by cold work is attributed to the formation of methane in microvoids. This methane can be isolated quantitatively, and furthermore, the amount of methane is in accord with the equilibrium 2H2 + Fe3C = CH4 + 3Fe. The micro-void volume, calculated from the methane content via the equation of state for methane, corresponds approximately to that calculated from the measured density decrement produced by cold work. THIS investigation was undertaken with the intent of employing the hydrogen atom as a probe in detecting specific crystallographic defects in cold worked steel. It was expected that different degrees of chemical interaction of hydrogen with the various types of defects could be utilized. The original aim was to assign concentration values to defect sites. The success of this approach requires that experimental conditions can be attained under which lattice-dissolved hydrogen equilibrates primarily with only one type of defect. A set of experiments which appeared potentially to embody these requirements was described several years ago by Keeler and Davis.1 They noted in the case of a mild steel (low carbon) that the solubility of hydrogen between 200° and 400°C near atmospheric pressure was notably increased by cold working the steel. The observed solubility was an order of magnitude greater than the normal lattice solubility. * Although the Keeler and Davis studies suggested that the density decrement effected by their cold-working operation might be related to the anomalous solubility of hydrogen, they offered no explanation of the relationship between the two effects. Prior to this work, Darken and smith3 had noted a similar effect of cold work upon enhanced sorption of hydrogen by steel when charged by acid pickling. In the light of present-day concepts, interaction between lattice-dissolved hydrogen and dislocations was strongly suggested. More recently, Hill and Johnson,4 working with a

Jan 1, 1962

By H. W. Schreiber, G. R. Castle

INTRODUCTION The small mining company faces the dilemma of how to finance the development of its properties. Many of these small companies don&apos;t have the financial resources to pay for development costs from their own funds and frequently they do not even have the financial strength to permit them to borrow the money needed for development. A project financing can sometimes be arranged in such a way as to solve this dilemma. A typical project financing will not provide the answer to the "little guy&apos;s" problem because most project financings require that the sponsors of the project provide completion undertakings and sometimes other undertakings. These undertakings are often a prerequisite to obtaining financing, and if the sponsor is not financially strong enough to provide the comfort that the lenders require, then the sponsor will have difficulty obtaining financing no matter what undertakings are offered. However, with a little imagination and the right set of circumstances, a project financing can sometimes provide the solution to the small mining company&apos;s problem. The Strathcona Sound Project is unusually suited as a case study because the sponsor, Mineral Resources International Limited,(MRI) was able to arrange a project financing for the development of the project even though the lenders probably would not have been willing to loan a similar amount of money direct to MRI based on the full faith and credit of MRI&apos;s balance sheet. The way that MRI was able to arrange this financing makes for an interesting story. THE CASE In early 1974, MRI owned 100% of a small to medium sized zinc - lead - silver massive sulfide deposit (Property) located 475 miles north of the Arctic Circle less than two miles from deep water on Strathcona Sound which is a shipping zone in the Canadian Arctic. The Property was situated at a desolate location except for an Eskimo settlement (Arctic Bay) which was about 20 miles west of the Property. In other words, the project required that complete infrastructure would need to be installed in this far northern location. Independent reserve and feasibility studies (Study) had been completed on the Property which confirmed a total of 6,825,000 tons of reserves classified and summarized as shown below on Table I: [ ] These reserves were based on 229 diamond drill holes totalling 58,909 feet and were established on a cut-off grade of 7% zinc and a minimum mining height of seven feet. The overall mining recovery rate was estimated at not less than 85% and not more than 90%. The feasibility study indicated that it would cost an estimated $45,044,000 to develop an underground mine, a concentrator, a town-site, a power plant, storage facility, loading dock, a tailings disposal area and an airstrip on the Property with an annual capacity of 525,000 tons of ore per year. The construction period was expected to take two years and projected capital costs were broken down as set forth below on Table II:

Jan 1, 1985

By W. I. Duvall, L. D. Sadwin

Three explosives with different detonation characteristics were tested by studying their cratering ability in a granite-gneiss. The strain wave generating characteristics of these explosives were also studied in the same rock medium. Correlations between the relative performance of three explosives as evaluated by crater studies and other methods of evaluation are indicated. Numerous test methods have been employed to evaluate the output performance of explosives; for example, the underwater explosion method, the airblast method and the ballistic pendulum method.&apos;*&apos; For blasting applications, the study of explosion produced craters and explosion generated strain waves are the most meaningful. This laboratory has employed these techniques extensively for many years and has shown that the detonation properties of explosives and their ability to generate strain waves in rock are related and that the amplitude and shape of the strain wave is related to some of the crater parameters such as slab thickness and fly rock velocity.3&apos;11 However, a good comparison between the relative performance of explosives as determined by the crater and strain wave methods had not been made. The purpose of this investigation was to determine if the relative performance of three explosives as determined by the crater method shows a correlation with the relative performance as determined by the strain wave method. If a good correlation exists between these two sets of relative performance, it should then be possible to relate the detonation properties of an explosive to its ability to break rock in a crater test. In most commercial blasting operations, the diameter of the blast hole remains constant even though the type of explosive may change. In general, it is the explosive volume rather than the weight which remains constant when two or more explosives of different density are compared. Therefore all tests in this investigation were conducted on a constant volume basis rather than on a constant weight basis. TEST SITE AND ROCK PROPERTIES The tests described in this paper were conducted at a granite quarry owned and operated by the Consolidated Quarries Div. of the Georgia Marble Co. at Lithonia, Ga. The tests were performed in an area where the exposed rock surface was nearly horizontal and where the general rock mass had few joints or faults. The rock has an apparent sp gr of 2.6 and a longitudinal propagation velocity of 18,000 fps. The characteristic impedance of Lithonia granite gneiss is 53(lb - sec/in3). EXPERIMENTAL PROCEDURE There are many parameters which must be considered in the study of explosion-produced craters. The role played by each variable in the explosive-rock-crater system can be determined by experimental techniques in which one parameter is varied while others are maintained constant. In this investigation, the crater geometry was studied as the depth was varied for each of three explosives. The explosive volume and rock-type were held constant for all crater tests. The experimental arrangement used in performing the crater tests is illustrated schematically in Fig. 1.

Jan 1, 1965

By L. S. Darken

IT has been known for sometime that in an ionic lattice, such as that of Ag2S or FeO, the migration velocity of the anion may differ markedly from that of the cation, the cation being usually the more mobile. It has been shown, for example, that during the formation of silver sulfide tarnish on silver, the tarnish layer grows principally by the motion of silver cations through an essentially stationary silver sulfide lattice. Similarly, the growth of wüstite scale on iron proceeds principally by motion of iron ions, this being accomplished with the aid of vacant iron lattice sites into which the iron may readily move. Likewise investigations of solid solutions of various salts show that there is usually considerable difference in the mobility of the different cations. Measurements of the mobility of various metals in liquid mercury indicate that the various metals move at different rates relative to the mercury. In view of the foregoing it seems reasonable to suppose that when any single phase solution is acted upon by a field, the atoms of different elements respond in different ways; in particular, that the force arising from a particular concentration gradient in a binary alloy would cause the atoms of one component to move with a drift velocity which is in general different from that of the atoms of the other component. The recent experiments of Smigelskas and Kirkendall1 support this viewpoint, since they found, in essence, that during diffusion in alpha brass zinc moves appreciably faster than copper. This was evidenced by the relative motion of inert molybdenum wires. Such a phenomenon is incompatible with the place interchange theory of diffusion proposed by several authors, most recently by Birchenall and Mehl.2 This theory has, however, also been questioned3.4 for other reasons, principally because of the high energy required for direct atomic interchange. The rather large difference between self-diffusivity, as determined by tracer technique, and mutual diffusivity, as determined with the aid of another element at low concentration, might also be interpreted as favoring the above idea; however, Birchenall and Mehl have pointed out that there is another possible interpretation of this difference; this is discussed later. A rather interesting and pertinent observation was made by Schwartz,5 who noticed that tungsten lamp filaments, heated by direct current, commonly fail by necking down in the region at the temperature gradient near the positive end, with a concomitant swelling at the corresponding position near the negative end. He introduces considerable auxiliary evidence to show that this phenomenon is occasioned by the motion of tungsten cations which migrate in the high temperature region from the positive end toward the negative end. The mechanism of this migration is not clearly understood. If, however, this experimental evidence be accepted, we are forced to conclude that alloying elements in the tungsten may migrate by the same or a similar mechanism, whatever it may be, at a greater or lesser rate, thus giving rise

Jan 1, 1948

By J. J. Jakosky

The strategic importance of the metallic minerals in our industrial economy, and the declining rates of discovery have focused attention on means of exploration for new mineral deposits. A consideration of exploration techniques leads to an attempt to evaluate the effectiveness of geophysics as a tool for mining exploration. One means of evaluation will be to compare the use of geophysics in petroleum exploration with its possible uses in mining. Geophysics in Petroleum Exploration During the past twenty years, the petroleum industry has established an effective exploration technique. Geology is the basic tool in those areas where reliable predictions can be made from surface conditions. In the other areas, where the geological studies are inadequate, they must be supplemented with geophysics or direct exploration, such as drilling. Since geophysical work is far less costly than any form of direct explbration, it is used almost exclusively as the means for obtaining the desired subsurface information. The geological and geophysical techniques are credited with locating sites which yielded one producer for three dry holes during the year 1947.&apos; For the wells located without geology or geophysics, there is a ratio of one producing well to sixteen dry holes. From these figures it is seen that the geological and geophysical techniques are more than four times as successful as the nontechnical exploration. It will be in order to consider further this ratio of one producer to three dry holes. The geophysical methods in use today† do not pretend to locate oil directly; their function is to locate anomalies or structures favorable for the accumulation of oil. For a producing oil well we must have not only structure, but also other favorable conditions, namely: petroliferous source beds, the required porosity and permeability in the reservoir rocks, an impermeable cap rock over the reser- voir, and the necessary water or gravity drive to force the oil into the bore hole. Since the geophysical work can only detect and sometimes delimit the anomaly, these other necessary conditions can be determined only by direct exploration. The success of modern geophysical work in locating and limiting the structure itself is remarkably high, probably over 95 pct accurate. Geophysical work renders an important service in the delineation of the structurally unfavorable areas and their elimination from the drilling phase of the exploration program. When attempting to locate any material of scarce occurrence in the earth, it is of paramount importance to know where not to dig. This elimination of barren areas is the least appreciated but is of great economic importance. For illustration, the difference between one producer to three dry holes, and one producer to sixteen dry holes, represents a saving of thirteen drilled wells, which would require an expenditure many times the cost of the geophysical work that might have revealed the nonfavorable structural conditions. The percentage of geophysically-located wells necessarily will continue to increase in the statistics of future years, as the search for oil is extended

Jan 1, 1950

By J. E. Lawrence

Copper-decorated lattice disorders in silicon have been analyzed by electron transmission microscopy, chemical etching, and P-N junction reverse current measurements before and following different gettering treatments. Lattice disorders acted as the nucleating sites for copper precipitation. Copper precipitates in silicon resist chemical etching, absorb electron beams more than silicon, and cause excess reverse currents. Totally gettered disorders will chemically etch rapidly, be transparent to electron beams at extinction contrast, and not contribute to excess reverse currents. Three different gettering procedures were performed to determine the effectiveness of different EXTRANEOUS metal contamination can alter the minority carrier lifetime and resistivity of bulk silicon as well as cause excessive reverse currents in semiconductor devices. Previous workers have reported such activity for gold,1,2 copper,&apos;-* iron,&apos; and rnanganese.2,5 Gettering is a method employed to render these impurities electrically inactive. However, some property of the junction-degrading metals prevents gettering procedures from being wholly reliable. The comparative effectiveness of gettering with different agents has been the topic of earlier publications.2,3,6-11 Two mechanisms for gettering metallic impurities have been proposed: the distribution coefficient mechanism by Thurmond and Logan7 and the compound formation mechanism by Goetzberger and Shockley.2 Both of these models evolved from data gettering mechanisms. First, phosphorus was allowed to enter a protective SiO2 film but remain away from the Si-SiO2 interface to test the effectiveness of the compound formation gettering mechanism. Second, phosphorus was allowed to enter the backside of silicon wafers to test the effectiveness of the lattice strain gettering mechanism. Finally, nickel was diffused into the backside of silicon wafers to test the effectiveness of the distribution coefficient gettering mechanism. In each case, copper precipitates dissolved as a result of the gettering treatment. Tightly packed precipitates will resist gettering more than loosely packed copper precipitates. acquired by the electrical analyses of gettered semiconductor materials. An electrical analysis, however, cannot identify the fate of the gettered metals. The radiotracer technique has recently been applied to determine the redistribution of metals following different gettering treatments.3,9,10 The spatial resolu tion of the radiotracer technique prevented the analysis of metal precipitates which contribute to the excessive reverse currents of P-N junctions. The gettering processes employed by the earlier workers, almost without exception, allowed the gettering agent to enter the silicon lattice. This procedure makes it quite difficult to differentiate between the distribution coefficient and the compound formation mechanisms. The metallographic analysis of gettered copper precipitates discussed in this work supplements the earlier work by obtaining direct evidence of silicon lattice defects decorated with copper before and following different gettering treatments. The effectiveness of a process which restricts the gettering agent, phosphorus, to a dielectric film and thus away from the silicon lattice is discussed in addition to the ef-

Jan 1, 1969