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By E. P. Shea

The Anaconda Co.'s Geological Department at Butte, Mont., was started early in the Company's history because of litigation involving vein ownership and extralateral rights. The problems, some of which were resolved in courts, were many because of the large number of veins and lode locations. Defensive action was required to prove ownership and protect against illegal exploitation of the downward and extra-lateral extensions of the ore bodies. In many cases it was necessary to define the outcrop of the vein and to show that its apex was within the boundaries of the lode claim. Exhibits illustrating geology were needed to present the cases clearly, and these could be made only after careful inspection and mapping of the underground workings by competent geologists. Also, The Anaconda Co. was one of the first companies to recognize the worth of skilled mining geologists and the value of accurate records in the search for new ore. The department was organized in 1900 by H. V. Winchell who, with D. W. Brunton, worked out the methods. Reno Sales was Chief Geologist from 1906 until 1948 when he was succeeded by V. D. Perry, the present Chief Geologist. Under their direction, F. A. Linforth, M. H. Gidel, C. H. Steele, E. P. Shea, C. C. Goddard, Jr., and W. A. O'Brien enlarged the scope of the work and improved the technique.

Jan 3, 1961

By Gunnar Thaning, Goran Mathisson

The iron ores mined by LKAB in the north of Sweden have excellent beneficiation properties. This gives LKAB a favorable position as regards the production of low silica pellets for direct reduction. LKAB has concentrated on developing and marketing grades of pellets for the Midrex-Purofer-HyL process group, i. e., such direct reduction processes carried out in a shaft furnace or a static bed using reformed natural gas as a reducing agent. The paper deals with properties and quality demands of iron ore pellets for such processes. Matters such as the effect of the residual magnetite in the fired pellets on the degree of metallization, the amount and composition of the slag phase in the pellets, the mechanism of the disintegration during reduction, the state of swelling of the pellets during the conditions prevailing in these processes, the importance of the porosity, the improvement of the reducibility and lowering of the sticking tendency of the pellets by small additions of suitable additives, and the influence of the pellet size are discussed. A special test procedure for direct reduction pellets has been elaborated by LKAB. Thus, three metallurgical properties are routinely determined separately, namely reducibility, reduction strength, and sticking. The test methods are described. Finally the present and future LKAB pellets for direct reduction are presented with respect to chemical analyses and metallurgical properties.

Jan 1, 1980

By X. Zhang, E. Li, Y. Xiao, Z. Yu, H. Han, J. Xie, J. Tian, W. Sun, K. Hong

In a pulp environment, the surface properties of magnesite and dolomite tend to be similar, due to the re-adsorption of dissolved calcium species, which makes the flotation separation difficult. In this paper, the chelating reagent EDTA is introduced to eliminate the adverse influence of the calcium species and to restore the selectivity of magnesite-dolomite separation using sodium hexametaphosphate (SHMP) as a depressant. Flotation experiments confirm that the recovery of magnesite improves significantly in the presence of EDTA. Zeta potential experiments confirm that the negatively charged EDTA4+ and HEDTA3+ species can form soluble and stable chelates with positively charged Ca2+ and Ca(OH)+ species preventing their adsorption on the magnesite surface. Adsorption measurements prove the addition of EDTA can decrease the adsorption of depressant SHMP on the magnesite surface. X-ray photoelectron spectroscopy (XPS) measurements further confirm the transformation from the surface of magnesite to dolomite in the presence of calcium ions, and the possible adsorption mechanism of EDTA and SHMP on the magnesite and dolomite surface. Key words: Magnesite; Dolomite; Surface dissolution; Flotation separation

Jan 1, 2020

By James L. Vanderbeek

INTRODUCTION Semiautogenous (SAG) grinding technology first started to be seriously considered for comminution circuit design in the mid-1960s as an alternative to the three-stage crushing circuits and rod-ball mill circuits in vogue at the time. Since this time the application of SAG mill technology has become widespread with over 250 mills larger than 20 feet in diameter sold (Jones 2002). The vast majority of concentrators constructed over the past quarter century have utilized SAG mill technology, and a SAG-based comminution-based circuit is generally the first choice considered for new projects. Since the first generation of SAG milling technology was applied, many lessons have been learned, and new supporting technologies have emerged which make the design, installation and operation of SAG &-based grinding circuits more robust and efficient. This paper will discuss the current status of SAG and associated technologies. MILL MECHANICAL DESIGN ISSUES Table 1 summarizes the manner in which SAG design capability has evolved over the past 30 years. Increases in mill diameter came slowly as the industry took a wait-and-see attitude as the technology of larger mill diameters was advanced. The first 32-foot- diameter mill was ordered in 1969. It was not until 1979 that the technology jumped to the 34-foot-diameter mill and 1988 for the first 36-foot-diameter mill. The first 38- and 40-foot-diameter mills were both ordered in 1996. At least five 38-foot-diameter and two 40-foot-diameter mills will be in operation by mid-2004. Advances in structural analytical techniques and increased computational power, coupled with field measurements of large operating mills, have increased the confidence of the mill suppliers in their designs and the operating companies in the viability of larger diameter mills. No failures of a 36-foot-diameter mill or larger have been

Jan 1, 2004

By Jamil M. Khalifeh, Shadia J. Ikhmayies, Bothina A. Hamad

"We computed the optical properties of the cubic niobium nitride (o-NbN) compound using the full potential linearized augmented plane wave (FL-LAPW) method within density functional theory (DFT). The complex dielectric function and optical constants, such as optical absorption coefficient, refractive index, extinction coefficient, energy-loss spectrum, and reflectivity, are all calculated and compared with experimental results. The behavior of the computed quantities is similar to that obtained experimentally, but the optical positions are shifted to lower energies. This shift was related to the strong interband transitions, which are located at energies higher than 5 eV for NbN- as they are for IV B transition-metal mononitrides- and they appear in the computed spectra and not in the experimental spectra. These interband transitions simply shift the position of the reflectivity edge or the screened plasma frequency to the longer wavelength side.IntroductionIn recent years, NbN, as a transition metal nitride, has become a very popular material due to its high hardness, melting point, wear resistance, chemical inertness and temperature stability, which makes it suitable for use as emission cathodes in microelectronics and sensors, optical films and micro-mechanics etc [l]. Niobium nitride has long been known as highly polymorphic material, for which several crystalline structures have been reported in the literature [2]. These structures include the well known super-conducting rock-salt (Fm-3m, or Bl) structure (o-NbN), the hexagonal structure with space group p63/mmc and prototype Fe2N (18fuN), the hexagonalstructure with space group p63/mmc and prototype NiAs ~-NbN) and others.There has been a lot of computational studies for the structural and electronic properties ofNbN [3, 4-7], but according to our knowledge there is not any computational work that has been devoted to study the optical properties of this transition metal compound. At the same time a number of authors had performed experimental work in this direction. For example, Xin-kang et. al [l] studied the microstructure and optical properties of magnetron sputtered NbN thin films. Torche et. al [8] studied the composition, structure, electrical and optical properties of nonstoichiometric niobium nitrides. Newport et. al [9] investigated the reflection and transmission spectra of cubic niobium nitride films, and Tanabe et. al [10] had investigated the optical parameters and reflectivity of reactively sputtered NbN thin films by using in situ ellipsometry."

Jan 1, 2013

By K. Parameswaran

This paper builds on presentations made at the Conference of Metallurgists (COM) 2015, COM 2017 and Extraction 2018 and associated papers published in the respective conference proceedings. Based on the classic Brundtland Commission definition of sustainable development as “development that meets the needs of the present without compromising the ability of future generations to meet their own needs,” the paper describes how metal mining can be compatible with sustainable development and how sustainability considerations have been applied in the primary copper industry, using several examples of sustainable mining practices from ASARCO LLC operations. Finally, the paper discusses how these considerations might be used in the future by discussing the need for developing a sustainable development strategy and how this strategy can be aligned with the United Nations Sustainable Development Goals. INTRODUCTION The primary copper industry comprises: mining (also referred to as “extraction”); mineral processing (also referred to as “beneficiation, “milling” or “concentration,”) which includes leaching, solvent extraction (SX), crushing, grinding, froth and flotation operations; and metallurgical processing which includes smelting and converting; refining, which includes fire-refining or anode refining and electro-refining; and electrowinning (EW). There are two routes for producing refined copper: hydrometallurgical and pyrometallurgical. The hydrometallurgical route comprises mining (open-pit and underground), mineral processing (crushing and grinding — for heap leaching only; leaching and SX) and metallurgical processing (EW). The pyrometallurgical route involves mining, mineral processing (crushing, grinding and froth flotation) and metallurgical processing (smelting, fire refining and electro- refining). The primary copper industry is capital, water, resource and energy intensive with the potential for significant environmental impacts, if the environmental aspects are not properly managed. ASARCO LLC (Asarco) was organized in 1899 as the American Smelting And Refining Company. Originally a consolidation of several lead-silver smelting companies, it evolved over the years into an integrated producer of primary non-ferrous metals, including copper, lead and zinc and associated co-products. Grupo México, S.A.B. de C.V (Grupo México) acquired Asarco in 1999. Today, Asarco is a vertically integrated producer of primary refined copper and associated co-products such as gold, silver, selenium and tellurium. Asarco operates three open-pit mines and mills, two leach, SX-EW plants, a copper smelter in Arizona and a copper electrolytic refinery in Texas.

Jan 1, 2019

By H. Y. Yang, L. L. Tong

For gold recovery, a Chinese refractory, high-sulfur gold concentrate was subjected to biooxidation with high pulp density in a single stirred-tank reactor. The flotation concentrate contained 36.9 percent sulfur (S) and 33.9 percent iron (Fe). Different experimental regimes for biooxidation were applied. With a mixed culture and by controlling the amount of addition of the gold ores and the pH of the biooxidation system, maximum iron oxidation of 82.6 percent and sulfur oxidation of 79.3 percent were achieved. The experimental results indicate that the pH control was beneficial to the biooxidation of this concentrate. Approximately 28.4 percent of elemental sulfur (S8) was found in the oxidizing slags. Two dissolution mechanisms of elemental sulfur are proposed: (1) FeS2 → S80 → S2O32− → SO42− and (2) FeS2 → S80 → SO42−. The high pH had a positive effect on the reduction of the S8. The results of thermodynamic analysis indicate that as an oxidant the dissolved oxygen can effectively reduce the Gibbs free energy of the pyrite oxidation process and, compared with the reaction of ferric iron as the single oxidant, the oxidation of pyrite is easier. The efficiency of the gold recovery was related to the iron oxidation as well as the sulfur oxidation. Gold and silver recoveries of 92.4 percent and 66.4 percent, respectively, were achieved.

By L. Shevenell, L. Stillings

The Acid Drainage Technology Initiative-Metal Mining Sector (ADTI-MMS) has established a Pit Lake Committee to enhance the science and understanding for the long-term management of pit lakes. Participation in this new committee is from members of federal and state agencies, industry, and academia, including numerous individuals representing 10 states. Work has begun on a pit lake literature search and review, database, classification, and sampling and monitoring procedures document. Coordination with the International Network for Acid Prevention (INAP) has been established. Future work will include preparing a prediction and assumption verification document, a report identifying variables upon which water quality is dependent, and an applied remediation technologies document, including an evaluation of the effects of backfilling.

Jan 1, 2002

By Walter R. Crane

PAGE I. Apparatus and Methods.......... 406 1. The Magnetic Circuit...........406 2. Apparatus Employed in the Traction-Method...... 406 a. The Coils............409 b. The Pole-Pieces..........409 3. Methods of Testing Fields Produced by Different Pole.Pices.. ..409 c. Testing with a Search.Coil........410 d. Testing with Iron-Filings and Glass Tube.. .. .410 4. General Forma of Pole-Pieces.........411 e. Flat Poles............411 f. Conical Poles........... 411 g. Spherical Poles...........411 h. Chisel-Edged (Chamfered) Poles.......412 II. Magnetic Fields...........412 5. Methods of Testinq for Magnetic Permeability...... 421 i. The Rod-Method..........423 j. Method Employed in These Experiments......424 k. Difference in the Results of the Two Methods..... 425 l. The Traction-Method.........427 m. Effect of Loosening the Charge.......430 n Corrections...........432 6. Theory.............433 o. Effect of Varying Weight on Tractive Force..... 434 p. Effect of Varying Pole-Distance.......436 q. Effect of Varying Magnetization.......436 T. Effect of Varying Size.. .......437 a. Summary,........... 441 III. The Relative Magnetic Permeability of Various Minerals,. 443 The form and strength of magnetic fields have attracted much attention. especially in connection with the designing of dynamo-electric machinery—an art which has been revolution-

Jan 1, 1902

By Thomas Kesler

THE Cartersville mining district, 35 miles northwest of Atlanta, Ga., has been of varying but continuous importance in the southern mineral industry during the past century. Noted chiefly for its production of brown iron ore, manganese oxide ores, barite, sienna, and magnesian limestone, the district and its environs have produced brick and tile clays, slate, gold, bauxite, and graphitic schist. Minor deposits of serpentine, sericite schist, copper ore, and red iron oxide have been prospected. The obvious deposits of brown iron ore, together with some associated specular hematite, were mined out years ago, although a little ore was left in the workings. Moderately steady production of sienna reached a peak about 1930, then declined rapidly. Manganese mining passed through a relatively active period from the World War to 1931, but has subsided to a small but rather constant output for the Birmingham market. How-ever, the White Manganese Corporation has prepared for possible increased production by constructing a new washer capable of handling about 300 tons of ore per day. Principal activity in the district proper has centered for some years in the production of barite and magne-sian limestone.

Jan 1, 1940

Alfred C. Young† (communication to the Secretary): Before the appearance of Mr. Scott's paper in these Transactions we were not specially interested in the investigation which he has started; but at his request we have endeavored to collect from musty records and the recollection of our old friends a brief chronicle of the progress made by this house. As 3000 instruments were manufactured by us before any descriptive record was kept, and 2000 more before the record contained more than a statement whether the instrument was a transit or a level, and sometimes its size, we approach the task with timidity, trusting that the reader will bear the difficulties in mind, particularly as the writer's predecessors, from whom, no doubt, the information desired could have been obtained, have passed away. Instruments for surveying were manufactured by David Rittenhouse, of Philadelphia, as early as 1760; but it was not until late in the first quarter of this century that there was any American market for an instrument outside of the ordinary surveyor's compass. With the advent of canals and railroads, and the more extensive development of the Pennsylvania coalfields, arose a demand for surveying-instruments to meet problems in engineering beyond the limited field of the compass. On May 1, 1820, in which year the practical mining of anthracite coal in Pennsylvania began, William J. Young, who had served his apprenticeship with one Thomas Whitney,

Jan 1, 1901

By Shinroku Matsuzaki

Data the measurement sensor installed with spatial distribution on the blast furnace were successively accumulated online from the process computer to the database system over a long period. This is a new system that accurately considers the relation with the installation position of each sensor, and picture computerization of the measurement data was developed. The overall operation state of a blast furnace, which skilled operators can see in their mind?s eye, was objectively visualized as pictorial information.

Jan 1, 2006

By J. F. Smith, J. R. Ogren, N. J. Magnani

The uapor pressrcres of magnesium over binary alloys of magnesium with twelve of the yare-earth eletnetzts have been measured by the Knudsen effuion method in the temperature range 675° to 910°K. These vapor-pressure measurments were combined with data concerning the tevtrlitzul magnesium solubility and the vapor pressure of pure magnesinm to evaluale the standuvd free energies of pluase jormation. These free-etzergy values indicate that the CsCl structures of the heacy rave earths tend to be somewhat less stable than those of the light rare earths. This dif-]eying- behaviov covrelates with differences which have been obsevz~ed in other alloy systetns wherein a phuse appeurs, disappeavs, or changes crystal stvucture as the atomic number of the rare-earth com-ponent is changed. This behauior also appears to correlate with the struclurul rariations within the rare-earth elements themselves, and it is speculated that cariations in the spatial extent of the 4f orbitals are responsihle. STUDIES of the phase relationships and crystal structures in the binary systems between rare-earth metals (lanthanons) and magnesium are extensive but far from complete. However, the currently available information1-10 does produce a rather interesting pattern. This is illustrated in Table I. If one excludes europium and ytterbium from consideration because of their generally atypical behavior, it can be seen from the table that the phase relationships in the magnesium-rich regions show a distinctly different pattern for the lighter lanthanons as compared to the heavier lanthanons. For the lighter lanthanons, LnMg2 phases occur from lanthanum to gadolinium with the cubic MgCu2 structure, LnMg3 phases occur from lanthanum to terbium with the BiLi3 structure, and magnesium-rich phases occur from lanthanum to gadolinium with stoi-chiometries between Ln5Mg42 and LnMg12. In contrast, for the heavier lanthanons, those LnMg2 structures which have been examined have the hexagonal MgZn2 structure, LnMg3 phases have not been observed beyond terbium, and the magnesium-rich phases occur with the a manganese structure near a stoichiometry of Ln5MgZ4. The heavy lanthanon-magnesium systems thus appear to be analogous to the Y-Mg system""2 wherein YMg has the CsCl structure, YMg2 has the MgZn2 structure, and the region Y4Mgz5-Y5Mg24 has the a manganese structure, and no other intermediate phases are observed. Similarity in alloying behavior between yttrium and the heavy lanthanons occurs commonly, and on this basis it seems likely that LnMg2 phases will be found with the MgZn2 structure in the binary systems of dysprosium, thulium, and lutetium with magnesium when the appropriate investigations are made. In the case of the magnesium-rich phases of the lighter lanthanons, only the Ce-Mg phase relationships have been investigated thoroughly and in detail, and until similar investigations are made for the other systems there will remain questions as to which magnesium-rich stoichiometries represent equilibrium phases and what systematic variations occur in the sequence from lanthanum to gadolinium. Thus the data in Table I show that only the LnMg phases occur with the same crystallographic structure throughout the sequence from lanthanum to lutetium. It was speculated that the relative stability of these LnMg phases might vary from one lanthanon to the next in such a way as to presage the differences which occur among the more magnesium-rich lanthanon-magnesium phases. On this basis the present investigation of the thermodynamics of phase formation was Gndertaken for the LnMg phases. PROCEDURE AND RESULTS A generalized phase diagram for the lanthanon-rich portion of a lanthanon-magnesium alloy system is shown in Fig. 1 where ß represents a high-temperature bcc

Jan 1, 1968

IN GATHERING material for this chapter on Yerington and the one to follow on Silver Bell, the A.S.& R. project near Tucson, Arizona, I was fascinated at the way the two stories paralleled each other. For example, here are a few instances: (1) The first copper mining in the Yerington district of Nevada was in the late 1860's; the first in the Silver Bell area in 1873. (2) Each district was served by a branch railroad about 25 miles long from a main line of the Southern Pacific (by quizzical coincidence); and, in each instance, the railroad was later abandoned and torn up. (3) Each district had a sizable blast-furnace smelter ten or fifteen miles from the principal mines, and in each instance the smelter was later dismantled for junk. (4) Up to 1954, the Yerington district was credited with a production of 100,000,000 lb of copper; the Silver Bell district with 80,000,000 lb. (5) In each district the entire production had come from deposits other than the low-grade ore bodies now being exploited. (6) In each instance, existence of the low-grade deposits of the Porphyry type was recognized in the period circa1910-1914 and a substantial amount of exploratory drilling had been done, on one deposit at Yerington and on two at Silver Bell. (7) In each instance, the properties containing the Porphyry ore were acquired by a strong company (Anaconda Copper Mining Company at Yerington and American Smelt-

Jan 1, 1957

By Zygmunt Sadowski

Problems encountered in barite flotation from various waste materials such as spent drilling muds are likely to be closely connected with the effect of chemical additives and metal ions present either added or present as contaminants, on the flotation. Fuerstenau and Palmer (1976) have studied in detail the adsorption of multivalent cations onto oxide and silicate minerals. It was observed that the adsorption of a multivalent metal species exhibits a sharp pH dependence which is related to the formation of hydroxy complexes of the metal ions in solution. Investigations on the recovery of barite from tailings ponds and mining wastes (Sullivan and Lamot, 1981) have shown that such barite materials can contain large quantities of carbonate and silicate minerals (including clay minerals). Also iron oxide slimes can be present. From these substances cations such as Ca2+, Mg2+, Fe2+ and A13+ can potentially dissolve and be present in the aqueous phase accompanying the various minerals. These ions and their hydrolysis products can have a substantial effect on any subsequent flotation scheme. The present study investigates the effect of the noted ions on both the stability and electrokinetic behavior of barite suspensions.

Jan 1, 1986

AT the meeting of January 28 which was held too late to be reported in the February MINING AND METAL-LURGY, Messrs. Taylor, Barron, Bassett, DeGolyer, Hutchinson, Norris, Rand, Reynders, Smith, Sweetser and Callow were present. Aside from routine matters, relating to finances and membership,, the Board author-ized establishment of a payroll account and payment by check. It also approved plans for a regional meeting to be, held at Cleveland on April 19 and 20 under the auspices of the Ohio Section and the Iron and Steel Committee. Following a report from the Committee on increase of Membership, Messrs. Barron, Bassett, and Sweetser were appointed as a special committee to con-sider the feasibility of increasing the dues. Mr. Read was made secretary of this Committee. A pleasant feature of the meeting was the presence of past-presi-dent Olcott and the presentation by him to the Institute of an elaborate scrap book, covering the excursion through Mexico made by the Institute in 1901. The meeting was preceded by a dinner at which Scott Turner spoke of the problems of the Bureau of Mines and the large volume of service work for the govern-ment it was now called on to perform. M. L. Requa discussed the need of more exact data covering our national reserve of minerals. E. N. Cooper gave a vivid picture of conditions in Mexico. W. H. Bassett told of the problems before the Institute of Metals, and Zay Jeffries told of the plans for that Division now being formulated. Max W. Ball reinforced what Mr. Requa had said relative to the importance and value of conservation studies as relates to minerals.

Jan 3, 1927

By Khaled Morsy

Cementitious seals are made of foamed cements with strength ranging from 100 to 600 psi. These cementitious seals are usually used at locations where the seal will be subjected to some convergence, assuming that this material can absorb entry closure without compromising the structural integrity of the seal. Prior to 2006, Lake Lynn Experimental Mine (LLEM) conducted full-scale tests on various cementitious seals designed to meet or exceed the 20-psi horizontal static load requirements of the old 30 CFR1 75.335. Both hydrostatic and dynamic loading tests were conducted. The structural response (pressure and displacement readings) obtained from these tests were recorded. The stability of the cementitious seal is based on balancing the load applied to the face of the seal from the explosion against the shearing resistance at the seal/rock interface. Therefore, the properties of the seal/rock interface, such as stiffness, cohesion, friction, etc. are critical to determine the stability of a cementitious seal. These properties are usually assumed by the researchers in their models. This paper emphasizes the importance of having the correct properties of seal/rock interface in the numerical modeling. FLAC 3D models were developed to simulate Celuseal2 cementitious seals subjected to both hydrostatic and dynamic loadings. Using the hydrostatic and dynamic loading test data conducted at LLEM, the static and dynamic properties of the seal/rock interface were back calculated. The FLAC 3D models showed good agreement with the test results.

Jan 1, 2009

By F. N. Lathe

In 1882, The Arizona Copper Co., Ltd., acquired producing copper mines at Metcalf and Morenci (locally called Longfellow). Metcalf is situated a distance of 7 miles, and Morenci a distance of 6 miles from the general office of the company at Clifton, Ariz. A reduction works with five blast furnaces was built in the center of the town of Clifton in 1884 and operated until January, 1914. Concentration of oxidized ores was begun in 1890-1891, in a mill built adjoining the smelter, and id October, 1893, a leaching process was started for treating tailings from the oxide mill. A sulphide concentrator with 300 tons capacity was built at Clifton and started treating chalcocite ores in July, 1896. This was the first mill to treat low-grade copper-siilphide ores successfully. Another concentration mill for sulphide ores was erected at Morenci in 1900. The sulphide mills are now being remodeled to treat ores by concentration and flotation, with a capacity of 4,000 tons at Morenci and 500 tons at Clifton. The leaching plant has not been running since September, 1914. The average yearly production from this company's mines and reduction works from 1885 to date has been: Pounds 10 years ended 1894................................... 6,864,902 10 years ended 1904................................... 20,439,614 10 years ended 1914................................... 32,665,905 Part of year 1915, to Sept. 12........................... 30,206,106 4 months of 1916, to June.............................. 15,964,840 June, 1916........................................... 4,900,000 Construction on a new smelting plant was started in February, 1912, and finished in February, 1914. In the Transactions, vol. 49, E. Horton Jones published "Unit Construction Costs from the New Smelter of the Arizona Copper Co., Ltd.," which fully describes the construction of this plant, with details of costs.

Jan 1, 1917

By T. J. Close

The Silver Peak Range North Wilderness Study Area was deleted from the list of US Bureau of Land Management lands in Nevada to be considered for wilderness designation. This decision was based in part on the US Bureau of Mines mineral investigation of the wilderness study area which found indications of precious- and base-metal-resources. The study area lies between the Silver Peak and Dyer mining districts of west-central Nevada. The Bureau examined 13 mineralized sites, most of which were previously unknown and unclaimed. These sites are along two zones that cross the study area from the Silver Peak mining district to the Dyer mining district. The two zones transect a volcanic center of fractured and altered rocks that contain epithermal veins of quartz and calcite with gold, silver, and base-metals. At the surface, these veins are poorly defined. Exposures of the more than forty veins examined were as thick as 17 ft and as long as 1000 ft. Samples from these veins contained significant amounts of precious- and base-metals-as much as 0.02 oz per ton gold, 2.1 oz per ton silver, 1.0% copper, 2.6% lead and 0.4 % zinc. No vein large enough or of high enough grade to be classified a mineral resource was disclosed by the sample data. However, most do have indications of precious- and base-metal-resources at depth. Subsurface exploration of some of the veins is recommended.

Jan 1, 1995

By Ralph Hultgren

FEW phase diagrams of alloys composed of two transition metals have been adequately studied, probably because of the high melting points involved. Transition metals are the elements that have inner shells incompletely filled with electrons. They comprise groups IIIa to VIIIa of the periodic table, including more than half of all metals. We have chosen to study two systems whose comparatively low melting points allowed the alloys to be melted in a molybdenum resistance furnace. The nickel-palladium system proved to consist of a simple series of solid solutions, but iron-palladium manifested several remarkable features. The main characteristics of the latter diagram were decisively established, but lack of time prevented precise determination of phase boundaries. The gamma to alpha transformation in this system is unusual and warrants further study. Grigorjew1 determined the liquidus and solidus of the iron-palladium system by thermal methods. He found a minimum melting point, but no eutectic. He also found that palladium lowered the gamma to alpha and raised the gamma to delta transformation temperatures of iron, with a complete series of solid solutions existing between gamma iron and palladium. His measurements also indicated a compound or super-lattice near the composition FePd3. Jellinghaus2 found that annealing at 500° C. greatly increased the magnetic coercive force of an alloy of composition FePd. X-ray dif-fraction photographs showed that a tetragonal ordered phase had formed during the anneal.

Jan 1, 1939