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By Robert Glass Cleland

THE CLOSING years of the nineteenth century witnessed a rapid expansion in Phelps Dodge activities in Arizona and other parts of the Southwest and a corresponding decline in its exporting and importing interests in New York. Before the close of another decade, this process had gone so far that the company was committed lock, stock, and barrel to its western undertakings. By 1910 the evolution that began with the tentative investments at Bisbee and Morenci was complete. An enormous increase in the domestic production of iron and copper, which made it increasingly difficult to find markets for imported cargoes of those metals from English mills, accounted in part for this radical shift in Phelps Dodge activities and interests. In the case of tin plate, the change was even more spectacular. In 1890 a seventh of the world's supply of pig tin passed through the hands of Phelps Dodge agents. In 1906, thanks chiefly to the McKinley Tariff of 1890 which imposed a duty of over two cents a pound on tin plate imported into the United States, the company received its last shipment of tin from England, and thus ended a form of

Jan 1, 1952

By Eugene P. Pfleider, Claus Freyberger

Generally, the different methods of financing new mining projects are not well understood by the engineers and supervisory personnel. Nor are the effects of these alternatives on depletion, taxes and profitability readily apparent to even the sophisticated management personnel without the aid of cash flow studies. Fortunately, with the advent of the computer it is possible now to simulate many different combinations of 1) equity, 2) loan and 3) production payment financing with little effort. A general computer program for cash flow analysis of mining ventures has been developed and applied as a case example to a 1967 feasibility study of the Underground Mining of Minnesota Taconite. The effects on profitability as measured both in rates-of-return and present value are presented for various financing combinations. In addition, percentage depletion rates were altered so as to measure the impact of this statuatory allowance. Based on the cost data as presented in the aforementioned 1967 feasibility study, and assuming 7% loans, the rates-of-return vary from 9. 9% to [00] % on equity variations and from 9. 9% to 11.4% on total invested funds.

Jan 1, 1969

By Philip R. Whitney

Deposition of manganese oxides is of common occurrence in streams of the north-eastern United States. Manganese entering the stream in solution in ground water is oxidized and deposited in the stream, primarily as oxide coatings on detrital materials. Prevalence and thickness of the coatings increases with increasing particle size in the coarse sand and gravel range. A number of metals of economic and environmental interest are enriched in these coatings. Samples of 8 to 16 mm pebbles were obtained from two streams in the Shawangunk region of southeastern New York State, an area of know71 Pb/Zn/Cu mineralization. The pebbles were leached to remove the oxide coatings and the resulting solutions analyzed for Mn, Fe, Pb, Zn, Cd, Cu, Co, and Ni. Trace-metal/Mn ratios in these streams are generally one to two orders of magnitude higher than regional background values. Profiles of trace- metal/Mn ratios along the streams show considerable detail; contributions of metals from tributaries are sharply reflected in the metal content of the oxides. The potential advantages and disadvantages of using coated stream gravel for geochemical prospecting and environmental studies are discussed in the light of these and other data.

Jan 1, 1976

By John G. Hall

The unstable metal market during 1949, with resulting lower metal prices, has focused every mine operator's attention on the problem of reducing operating costs. Improvement in mining methods, use of modern mechanical mining equipment, and increasing the efficiency of the labor force are the tools with which we will have to work. Careful planning is necessary to coordinate all phases so that no one phase is overdone. A mine may become over-mechanized if, for instance, capital charges against new equipment exceed the savings in labor costs, or where a large enough tonnage is not produced. The cooperation of labor is essential to any mechanization program. There have been too many instances where mechanization and improvements have done nothing more than make up for a decrease in labor efficiency, thus bringing the production of labor back to its old standard. The operator has gained little and labor has gained only a "softer job." In any mechanization program there are gains to be had by both the operator and labor. By the efficient application of modern equipment and improved mining methods the operator should gain by decreased costs, and labor may profit by receiving a share of these decreased costs.

Jan 8, 1950

By Charles Hart

THE art of electric smelting came with the turn of the present century and owes its existence to the introduction of alter-nating current, which found its first wide use in the establishment of the great power plants at Niagara Falls, N, Y. Prior to that time current was largely direct. The fur-naces were electrolytic in nature and found their first metallurgical use in the produc-tion of aluminum, and this process still prevails. The normal production of pig iron up to that time was carried on in blast furnaces in which charcoal, coke and anthracite were used as the fuel. This new electric process called for sufficient carbonaceous material to reduce the oxides and impregnate the pig iron with sufficient carbon, but the remainder of the energy was to be supplied by electric power. The chemical reactions are essentially the same in electric smelting as obtains in the older blast furnace. All of these data are so well known in both methods as to need no discussion at this time, for they can be found in scientific publications and books written during the first two decades of this century.

Jan 1, 1940

By Robert Glass Cleland

IN SPITE of its widely ramified interests in manufacturing, mines, lumber, railroads, and real estate, Phelps, Dodge & Co. remained primarily interested in exporting and importing, in buying and selling, and William E. Dodge, the directing-partner, consistently styled himself a merchant. After 1849 the profits of the company mounted steadily for seven years until they approached the half-million mark, but in 1857 another severe panic ended the long period of national prosperity that had begun some fifteen years before. Extravagance, indebtedness, and inflation again took their costly toll; or, as the New York Herald of June 27,1857, declared: Governmental spoliations, public defaulters, paper bubbles of all descriptions, a general scramble for western lands and town and city sites, millions of dollars, made or borrowed, expended in fine houses and gaudy furniture; hundreds of thousands in the silly rivalries of fashionable parvenues, in silks, laces, diamonds and every variety of costly frippery are.only a few among the many crying evils of the day. The worst of all these evils is the moral pestilence of luxurious exemption from honest labor, which is infecting all classes of society. The country merchant is becoming a city stock-

Jan 1, 1952

THIS method of melting with a little wind furnace is called by many melting with air. It is a method that is done with little labor. First a furnace is made with crucibles and charcoal. It is small or large as you wish, without blast from bellows, but not without a draft of air which proceeds from the place where it is made and from the arrangement of the furnace.* This, after a certain period of time, has the effect of melt- [ ] gin the thing in the quantity that you wish, provided, however, that you proportion it properly to the space, to the fire, and to the air which makes the wind. In order to make this, the aforesaid furnace is first made of bricks, or it is dug out of an elevation of stone or [106V] in a wall of clay. It can also be made portable with iron bars and loam as I shall tell you. However you may make it, you must place it in a spot that is windy, for instance, in some large room or opposite doors or windows. It is made round or square as is most pleasing to him who is to make it. But here we will now say that it is to be made square for greater convenience of building with bricks. Having chosen the place, make it a half

Jan 1, 1942

THE 127th meeting of the Institute was held in New York, Feb. 19 to 22, 1923. In addition to the usual large volume of technical matters under consideration, the meeting was particularly noteworthy for the amount of attention given to its business session; the convention of local section representatives also was full of interest. The total registration was 1201. The annual business meeting on Feb. 20, President Dwight presiding, was attended by 125 members, who listened with marked attention to the reports and addresses of the several officers. The chairman departed from the stipulated order of business in order to allow more time for the presentation of remarks on the state of Institute affairs. The previously pub-lished reports of the officers were accepted, as printed. On the report of the tellers, the following officers were declared elected: E. P. Mathewson, Director and President-District 0 T. T. Brewster, Director and Vice-president-District 6 Frank M. Smith, Director and Vice-president-District 11 W. H. Aldridge, Director-District 0 G. H. Clevenger, Director-District 1 A. N. Diehl, Director-District 3 Reno H. Sales, Director-District 7 Seeley W. Mudd, Director-District 10

Jan 3, 1923

By A. H. Grobe, F. N. Rhines

THE constitution of the indium-zinc alloy series has been investigated by Wilson and Peretti,1 who determined the liquidus and eutectic temperatures by the conventional method of cooling curves and the eutectic composition by analyzing eutectic exudations. Recent developments affecting the availability of indium and consequent increased interest in its applications make a more complete knowledge of the constitution of its alloys desirable. As a part of a program for the reexamination of the constitution of indium alloys by precision methods, the indium-zinc phase diagram [ ] (Figs. I and 2) has been redetermined in its entirety. The eutectic temperature (143.5°C.) reported by Wilson and Peretti has been confirmed exactly, but their value of the zinc concentration at the eutectic, 4 per cent, was found to be high; the new value is 2.8 per cent of zinc. There is also a rather large difference between the forms of the liquidus curves of Wilson and Peretti and those found in the present studies. The solidus curves herein have been located for the first time and the limits of solid solubility have been tenta-

Jan 1, 1944

By Wolfgang Pietsch

Prior publications have shown that the structure and characteristics of direct reduced iron produced by direct reduction from iron ores or iron ore pellets depend on many parameters which include process variables, such as, reduction temperature, reduction gas composition, and type or origin of the raw material. Most of the published literature deals with direct reduced iron produced in the laboratory at theoretically interesting but commercially uneconomical or technically impossible conditions. Much of the work was carried out in pure carbon monoxide in pure hydrogen, or in such mixtures of carbon monoxide and hydrogen which are of no commercial interest. Other results were obtained at temperatures which are too high and would cause sticking in large scale plants. For this reason, work was initiated by Midrex Corporation to investigate the influence of raw materials and reduction temperature on structure and characteristics of direct reduced iron. The composition of the reducing gas used to prepare the samples for this study produces results corresponding to those obtained with a typical commercial gas. The temperatures at which reduction was carried out are in a technically feasible range. This paper reports on the results.

Jan 1, 1979

By H. L. Shergold, O. Mellgren

Concentration of fine quartz particles at the iso-octane/water interface has been investigated under different conditions of pH and dodecylamine concentration. The results obtained from the related studies on the effect of amine concentration and pH on the interfacial tension, adsorption density, electrokinetic potential, contact angle, and concentration of the various amine species in the system are presented. A good correlation was obtained between these different variables. It is well-known that very fine mineral particles are difficult to float in conventional flotation machines. Flotation rate studies have revealed that the rate of flotation of fine mineral particles is much smaller than that of coarser size fractions. The theories accounting for this behavior have been discussed by Arbiter and Harris1 and also Meloy.2 Theoretically, a hydrophobic fine particle might never make contact with a bubble because of the presence of an energy barrier in the vicinity of the air/water interface.' This energy barrier will have electrostatic, hydrodynamic, and Van der Waals force components. It was thought that by using an oil phase instead of air the energy barrier would be decreased so that fine particles could be concentrated at the oil/water interface more readily than at the air/water interface. The technique used involves dispersing the fine particles in water, containing the appropriate chemical reagents, and injecting a fine dispersion of iso-octane oil droplets into the pulp. After vigorous conditioning, the pulp is passed into a separating column where the oil droplets coated with a layer of mineral particles rise to the surface to form a separate layer. Air is introduced into the base of the separating column to ensure that heavy agglomerates of oil and particles report with the organic layer. This technique has been described previously4 and adopted by Lai and Fuerstenau5 who studied the alumina-dodecyl sulfonate system. The interfacial phenomena in the system composed of hematite, water, and iso-octane in the presence of sodium dodecyl sulfate have been studied and the results reported" earlier. This paper describes the results obtained from investigations into the interfacial phenomena in the quartz/water/iso-octane system in the presence of dodecylamine. The technique used in measuring the interfacial tension, electrokinetic potential, contact angle, and adsorption density were similar to those described previously? Materials Selected pieces of a high purity natural quartz, from the Isle of Man, were crushed in a laboratory jaw crusher and pulverizer. The — 52+72 mesh size fraction was retained and leached with successive washes of hot concentrated hydrochloric acid to remove iron impurities. When no iron was detected in the solution by ammonium thiocyanate, the quartz was washed thoroughly with distilled water until the conductivity of the wash water assumed that of the distilled water. Samples of 25 g of the —52+72 mesh quartz were ground for 5.25 min in an agate vibratory mill. The ground product was 100% —44 m and 57% —10 am, as determined by the Andreasen pipette. The specific surface area of the sample used for the adsorption and flotation tests was 0.94 sq m g-l. This corresponds to a mean particle diameter of 2.4 am. The —44 am quartz sample was stored under vacuum in the presence of silica gel crystals. For the contact angle determination between the three phases, quartz, iso-octane, and water, a piece of the natural quartz was ground into a block about 15 mm long, 15 mm wide, and 5 mm thick. One surface of the block was then polished by successively finer grades of silicon carbide "paper." The final polishing was conducted with alumina on a "hyprocel" paper. The polished quartz specimen was cleaned using nitric acid and ethyl alcohol followed by a wash with distilled water and then stored under distilled water. This pro-

Jan 1, 1971

By C. W. Covington, H. C. Cook, J. F. Libsch

Sputtered aluminum thin films were prepared in each of two conventional bell-jar vacuum systems. One system utilized an inner "getter sputtering" enclosure; the second system was a standard diode sputterirlg arrangement. Consistent and repeatable film properties were obtained in both systems provided sufficient cleanup and presputter time was allowed. The various problems associated with aluminum sputtering are discussed, with pavticular attention to the vzinimization of film contamination by outgassing and oxidation. The growth and structure of the aluminum thin films were studied with the aid of electron wzicroscopy and related to deposition rate, substrate temperature, and film thickness. The resistivity of the films was correlated to film structure and surface roughness. Resistiuities as low as 3.5 microhm-cm (2.3 x bulk resistiuity) were measured for relatively thick films (20,000). THIS investigation was undertaken to explore the problems and film characteristics associated with the sputtering of aluminum. Earlier work reported on aluminum sputtering has stressed the contamination of both the cathode and film as well as abnormally low deposition rates.' Data on sputtering yields,3 however, indicate that aluminum sputtering could be practical. Recently, it was shown by Theuerer and Hauser3 that aluminum sputtering was feasible in a conventional oil-diffusion pumped vacuum system provided an inner "getter sputtering" enclosure was employed to minimize gaseous contamination. This technique employs the getter action of aluminum to produce extremely low reactive gas partial pressures in the deposition zone. Aluminum films have already found use in solid-state electronic devices such as transistors and integrated microcircuits. To the present time, most aluminum films have been prepared by evaporation due to the ease with which this metal can be evaporated. Controlled sputtering of aluminum offers a number of advantages over evaporation, however, such as 1) manufacturing compatibility with other metals which must be sputtered, 2) better control of process variables resulting in more repeatable and uniform films, 3) generally better adhesion resulting from higher-energy metal atoms, 4) built-in material supply for continuous operation, and 5) the ability to deposit alloys. The data presented in this paper are the result of two separate studies. One study utilized a small "getter sputtering" enclosure (System A) and was concerned with the structure and properties of thin aluminum films up to about 1600A thick. In this thickness range, study of the film structure was possible with transmission electron microscopy. The second study was conducted with a conventional diode sputtering apparatus (System B) and covered $ much wider range of film thickness up to about 34,000A. Emphasis was placed on developing techniques which would extend aluminum sputtering to an existing in-line continuous deposition process.4 I) EQUIPMENT AND PROCEDURE System A. Fig. 1 shows a schematic of the "getter sputtering" inner chamber used and Fig. 2 is a photograph of this chamber mounted on an 18-in. access ring of a standard liquid-nitrogen trapped bell-jar vacuum system. This chamber was designed after a similar system used by Theuerer and auser.3 The configuration allowed the glow to emanate in all directions from the cathode. Argon (99.99') was allowed to enter only at the top of the chamber such that most of the reactive gases entering with the argon were reacted with the aluminum vapor and deposited on the chilled walls of the chamber before reaching the deposition zone. Provision was also made as shown, Fig. 1, for heating and cooling the substrate from about 20" to 400°C. Two substrate materials were used: Corning 7059 glass (12 by 12 by 0.048 in.) and carbon films about

Jan 1, 1967

By B. J. Kochanowsky

To improve blasting methods it is necessary to know how the explosive force acts and how rock resists this force. Because of the tremendous power developed within milliseconds and the great number of other factors directly affecting the technical and economic results, an analysis of the fundamentals of blasting theory is difficult. But since the rules used for layout design and for calculations of size of explosive charges are based on theoretical assumptions, complete knowledge of blasting theory has great practical importance in mining. Analysis of Blasting Theory: It is interesting to note the opinion of blasting experts with respect to contemporary blasting theories. F. Stussi,' Professor of the University of Zurich, stated: "We do not have enough experience yet to change our army engineering regulations in blasting and base it on new fundamentals. It is our duty to collect more practical data and to do more research in blasting to close this gap." K. H. Fraenkel,' editor of the Manual on Rock Blasting published in 1953 in Sweden and written by well-known Swedish, German, Swiss, and French blasting and explosive experts, said: "To the best of our knowledge no suitable formulas for civil blasting work are to be found in the American, French or German literature."

Sep 1, 1955

By J. A. Herbst, K. Rajamani, M. Siddique

This paper presents an investigation of the accuracy of population balance model predictions for ball mill scale-up. Experiments performed in 25.4 x 29.2 cm (10 x 11.5) batch mill are used to estimate linear grinding rate parameters that, in turn are scaled according to specific power draft to predict performance in 381 x 292 mm (15 x 11.5 in.) and 762 x 457 mm (30 x 18 in.) batch and continuous ball mills, respectively. Results are presented for wet and dry grinding of two homogeneous solids, limestone (soft) and quartz (hard), and one heterogeneous solid, a complex molybdenite ore. In all cases good agreement between predicted and experimental product size distributions was obtained.

Jan 1, 1983

By C. G. Dunn, F. W. Daniels, M. J. Bolton

Recent observations on grain boundary movements in sihcon iron have indicated the possibility of studying grain growth phenomena in two-grain specimens in which several variables affecting growth are readily controlled. These variables are (1) the energy per unit area (?) in the grain boundary, (2) the orientation relationship of the two grains, and (3) the radius of curvature (7) of the moving boundary. Ideally, one grain A should be a narrow rectangular parallelepiped adjacent to a second grain ß as shown two dimensionally in Fig 1. Such a two-grain group becomes unstable when one end of grain A is shaped according to the dotted line. Since the width w of grain A remains constant during growth of grain B, T should also remain constant. The other vari- ables mentioned above can be controlled in the preparation of each two-grain specimen.l,2,3 For a parLicular orientation of each grain, is not necessarily fixed; ? may also depend on the orientation of the grain boundary, but this may be controlled to some degree. The energy relationships for the gowth of grain ß may be derived from the more simple arrangement of two grains A' and B' shown schematically in Fig 2. Here B' largely surrounds A'. Assume these grains are oriented with a common plane parallel with the flat

Jan 1, 1950

By G. R. Heckman, H. J. Murphy, C. T. Sims

An incestigation has been made of the effects of heat treatment and alloy composition on the long-time stress-rupture properties and structural stability of the similar nickel-base alloys Udimet-500, Lrdimet-520, and Udimet-700. Rupture test data are presented at stresses ranging from 4 to 50 ksi at temperatures from 1450° to 1900°F for times up to 14,000 hr. Ductility response is emphasized. Optical and electron tnicroscopy were complemented by X-ray diffraction analyses of extracted phases to relate microstructural stability to the observed rupture properties. Particular attention is paid to Udimet-520 since structural characteristics of this alloy appear to vary somewhat from its sister alloys. Both cast and wrought performance of Lrdimet-500 are discussed. The computerized PHACOMP calculational technique, based on electron-vacuncy theory, is discussed and related to structural stability where appropriate. Electron microscopy and microprobe techniques were used to conduct evaluation of the oxidation characteristics of Udimet-500 exposed in air for 16,100 hr. The steady advance in strength and reliability of nickel-base superalloys continues to be one of the high points of modern metallurgy. The stress capability of these materials has increased steadily, allowing higher and higher operating temperatures in the highly sophisticated aircraft and industrial gas turbines now on the market. The attendant increase in efficiency, of course, means greatly improved power output. Gas turbines for industrial and marine use have long been designed with these objectives paramount the usual design requirements in terms of time of service being 100,000 hr. High-efficiency, long-life aircraft such as the supersonic transport require superalloy engine materials with high-strength and long-time structural stability. Thus, materials studied for and operating experience from industrial gas turbines provide a good reservoir from which technology of high value to the SST program can be drawn. This study is one such case. Three prominent nickel-base super alloys—Udimet 500, Udimet 520, and Udimet 700 were extensively evaluated for industrial gas turbine bucket use. Particular attention was directed toward structural stability as a requisite property. Within the present context, structural stability is defined as freedom from the propensity to form strength-robbing or embrittling phases such as u,p,x,or Laves, and the ability to maintain useful rupture strength and ductility throughout design life. MATERIALS The three alloys, cast Udimet 500 (U-500C), Udimet 520, and Udimet 700, were chosen for detailed evaluation based on preliminary studies which indicated that U-500C and U-520 possessed comparable rupture strength capabilities, and that U -700 had a greater strength capability but somewhat poorer ductility than wrought U-500. The nominal compositions of the three alloys, along with the compositions of the heats investigated, are presented in Table I. PROCEDURE Dimensionally rejected U-520 buckets from Special Metals Corp. heat 63370 were heat-treated using the four cycles delineated in Table 11. Cycle A was investigated to determine the effects of a shortened 1700°F primary age. Cycle B was considered a "standard" treatment. Cycle C investigated a higher solution temperature in combination with a shortened primary age, while cycle D assessed the effect of the higher solution temperature alone. These heat treatments were designed to produce optimum combinations of rupture strength and ductility through maximum y' development, the development of a y' grain boundary cushion, promotion of MC carbide degeneration reactions, and agglomeration of resultant M23CB. Since one of the premises of the evaluation of U-520 was that rupture strength would be equivalent to U-500, forged U-500 buckets from Special Metals Corp. heat 62916 were heat-treated with cycles A, B, and C to provide comparison. The heat-treated structures of U-520 and U-500 are illustrated in the 8700 times electron micrographs of Fig. l. The U-700 tested was all from 3-in.-diam hot-rolled and centerless-ground rod from Special Metals Corp. heat 2-1426. Two heat-treatment cycles were employed, E and F of Table 11. Cycle E is a standard four-step, triple-age treatment intended to provide an optimum match of strength and ductility through well-developed matrix and grain boundary y', as recommended by U-700 vendors. Treatment F is a shortened , single-age cycle which could provide a significant processing cost reduction should adequate strength and ductility be maintained. Following heat treatment, rupture specimens of U-500 and U-520 were machined from the buckets and tested. Standard rupture bars of U -700 were machined from the heat-treated rod and rupture-tested. Failed and withdrawn rupture bars were prepared and examined by optical and electron microscopy. Select specimens were electrolytically digested, and the residues analyzed for carbide and topologically close-packed phases using CrKa or CoKo radiation. Of the six different U-500C heats evaluated, five were cast by Misco Precision Casting Co. and one was cast by Haynes Stellite Co. Cast-to-size rupture bars

Jan 1, 1968

By Wayne L. Dowdey

With proud humility and keen anticipation, I accepted the office of President of the Institute one year ago, and it is with a great deal of pride in you-our membership that I make this report. You are the reason for a productive and prosperous year for AIME. Superior, good or satisfactory results were experienced in 1978 from almost everything we did as a leading engineering technical society. I recognize and pay tribute to the WAAIME organization. Their work is vital to our efforts, and their programs have proven effective. WAAIME can depend upon our continuing support.

Jan 6, 1979

By D. F. Strong

Most Newfoundland mineral deposits can be clearly classified as within rocks formed either as accreting plate margins (ophiolitic pyrite-chalcopyrite massive sulfides such as Betts Cove, Whalesback, York Harbour, chromite at Lewis Hills, and asbestos at Baie Verte), at consuming plate margins (Kuroko-type polymetallic massive sulfides such as Buchans and Pilleys Island, porphyry-type Mo-Cu at Rencontre, fluorite at St. Lawrence), or within plates (zinc deposits at Daniels Harbour, sedimentary iron ores at Wabana, manganese in Conception Bay.) As these metallogenic patterns can be convincingly extrapolated southward into the Appalachians and northward to the Caledonides, they provide an important means of eliminating and selecting areas for particular exploration targets. Some criteria are described for the recognition of these environments of differing economic potential.

Jan 1, 1975

By Eric Jette

The nickel-chromium alloys form the base f for many industrial heating alloys, so that this system is of considerable practical importance. The literature on these alloys, however, contains much conflicting evi-dence, not only regarding the solubility limits of the terminal solid solu-tions at different temperatures but even regarding, the number of phases existing in the system. Part of the difficulty undoubtedly arises from the fact that chromium of sufficiently high purity has been available only during the last few years. A second and possibly even more impor-tant difficulty arises from the ease with which chromium reacts with silicon and carbon compounds and the atmosphere to form silicides, carbides, nitrides and oxides. Pilling and kihlgren1 in 1929 reviewed the existing scanty information. They did not consider the diagram by which they summarized the various bits of information to be entirely satisfactory. Matsunaga2 investigated the system by thermal analysis, microscopic examination and other means. Electrolytic nickel of 99.9 per cent purity and thermit chromium containing 0.30 per cent al, 0.40 per cent fe, 0.25 per cent si and 0.04 per cent c were used. A tammann furnace with hydrogen flowing through it was used for melting. Sekito and matsunaga3 reported an x-ray, investigation presumably on these same

Jan 1, 1934

By R. W. Prouty

THE methods of sampling and ore estimating used at the Copper Queen Branch, Phelps Dodge Corpn., as applied to the Copper Queen mines at Bisbee, Ariz., fall into two divisions because of the difference in occurrence, manner of prospecting, and methods of mining: that for the underground operations and that for the Sacramento Hill steam-shovel operations. The orebodies of the Warren district may be divided into three classes: Replacements of limestone, replace-ments of porphyry, and replacements of contact breccia The first class is more or less intimately related to porphyry intrusions, although in badly fractured country this relationship may not be well shown. These orebodies are mainly oxide and carbonate ore and very irregular, both in size and outline, although usually roughly lenticular and following the bedding of the limestones. There is usually quite a sharp boundary between the ore and waste in the carbonate and oxide orebodies and sampling is not necessary to determine the limits of commercial ore. In the sulfide orebodies it is exceedingly difficult, without sampling, to deter-mine the boundary between commercial ore and the surrounding low-grade or barren pyrite. Calculations made a few years ago showed that these orebodies had an average thickness of 35 ft. As some of the ore-bodies have a thickness of from 100 to 300 ft., it can be seen that the smaller ones form a difficult problem both in prospecting and in estimating.

Jan 11, 1922