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By Jannie van Deventer

"Innovation in the minerals industry has been lagging behind comparable industries like oil and gas. An incremental innovation culture that tolerates long lead times between invention and adoption has been exacerbated by a research grant structure that inhibits radical idea generation. Entrepreneurs who can make the link between ore source, technology and finance will cause a shift in innovation culture and open up substantial opportunities in the minerals industry of the future. By extrapolating existing trends in technology within and outside mineral processing, a crystal ball vision of future innovation is shaped with the aim to lower energy and water demand, reduce CO2 emissions, decrease operating and capital costs, reduce environmental impact, and secure a social licence to operate. Advances in nanotechnology, advanced materials and biotechnology will impact mineral processing, but the initiative for technology transfer must come from mineral processors. Laminates of graphene oxide can offer efficient filtration and separation media, while microfluidic devices will be used for desalination, solvent extraction and analysis. Substantial progress is expected on benign lixiviants and separation agents, such as nanoscale supramolecular hosts that can serve as high-capacity, selective and recyclable ligands and sorbents, and solid aminobiphosphonate-based adsorbents. Radical ideas for the recovery of precious metals from non-assayable ores and the generation of energy above unity will be adopted in selected minerals projects. In-situ mining in which microbes generate lixiviants at mineral surfaces will simplify processing circuits. Specific ores will be subjected to microwave processing and electropulse liberation to enhance recovery. Ultrafine grinding using devices of low energy consumption will be done mainly dry, followed by dry separation. New flotation cells will remove efficiently either coarse particles or ultra-fine particles, with mineral surfaces being modified not just by new reagents but also by selective microbes. Innovation in mineral processing indeed has a bright future."

Jan 1, 2014

By R. N. Gow

Acidic treatment of enargite (Cu3AsS4) dissolves both arsenic and copper from the mineral and then attempts to separate them in the leach solution. The reactivity of enargite was examined in acidic solutions, over the pH range 1-7, to determine a potential range for co-dissolution.. Enargite mineral samples from Butte, MT and Quirivilca, Peru were used as working electrodes in a cyclic voltammetry corrosion cell setup, which were then cycled multiple times over -1000 to 1000 mV. Surface reactions and transitions were characterized using in-situ Raman spectroscopy, which were then compared to updated predominance diagrams for the copper-arsenic-sulfur system from a previous study done under alkaline conditions. The region of co-dissolution is limited to > 600 mV vs. SHE and pH < 1 under the proposed diagram.

Feb 23, 2014

By M. A. Gimenes

The utilization of chlorination in extractive metallurgy and advanced ceramics areas has been widely investigated as a preparative route in order to obtain intermetallic compounds, which are used as precursors in the development of new materials and process. The major processes of decomposition of rare-earth ores use sulfuric acid and sodium hydroxide at high temperatures, however there is not much work concerning chlorination. In this work, a systematic study of the reaction between xenotime (REPO4), chlorine and carbon has been performed. Particular emphasis was on kinetic studies to establish optimized conditions for the reaction. The kinetics of chlorination of xenotime raw material by rare-earth elements/compounds has been studied over a temperature range from 600°C to 950°C. The influence on the rate of conversion of xenotime to RECl3 on temperature, partial pressure of chlorine, carbon content, and particle size were investigated. A global rate equation that includes these parameters has been developed. The results show that the process follows the unreacted core-shrinking model with a formation of a porous product layer. The powder X ray-diffraction technique corroborated this model showing clearly the patterns related to the formation of yttrium oxychloride (YOCl), indicating that the reaction mechanism involves the presence ofan intermediate step before the formation of lanthanide chloride.

Jan 1, 2000

By S. Bozorgi, K. Anders

"The automotive applications of heat treatable AlCu cast alloys are designed for performance at high temperature, which can be improved using specially alloying element as well as different heat treatment. In this research work an effect of alloying element such as Cu, Ni and heat treatment on microstructures and mechanical properties of AlCu alloy were investigated using optical microscope (LIMI), scanning electronic microscope (SEM) equipped with energy dispersive X-ray detection (EDS), Differential scanning calorimetry (DSC) and mechanical testing. It was found that during solidification most of the elements Cu, Mg and Ni segregated at the grain boundaries in the form of Al2CuMg or Al7Cu4Ni and a very small part of Cu and Ni element dissolved in the FCC-Al matrix. The latter is not completely reclaimable for strengthening mechanisms in FCC-Al matrix in its as-cast state. The results of mechanical test show that yield strength and ultimate tensile strength increases after heat treatment significantly compared with the as-cast state. Furthermore the mechanical properties at elevates temperature (240°C) is higher with higher Cu+Ni+Si containing alloys compared with the less Cu+Ni+Si containing alloy.INTRODUCTION Due to the high strength-to-weight ratio, high strength and ductility at room- and elevated temperature, AlCuSi cast alloys are widely applied in the automotive industries specially for producing cylinder head and engine block, where modified alloys with enhanced metallurgical properties are always needed to satisfy the ever increasing demands for the applications. The AlCu based cast alloys can be strengthened by age hardening. The precipitation processes from which this hardening is derived can be attributed to the presence of selected trace element additions or micro alloying, which can change the process or kinetics of precipitation in age hardenable AlCu cast alloys (Polmear, 1998; Morris, 1991). Furthermore their strength is mainly controlled by the aging process through the precipitation and growth of very fine precipitates of the ?'-phase (a semi-coherent, metastable form of the equilibrium Al2Cu phase) from the Al and Cu Guinier-Preston (GP) zones. Several studies have shown that solute clustering occurs prior to the precipitation of GP zones, and this modifies both the nature and kinetics of the precipitation process. The typical size of GP zones is in the order of tens of nanometers, and the chemical composition of these precipitates is not easily measured, even with a typically analytical electron microscope (Polmear, 1989)."

Jan 1, 2018

By S. S. Pathak, S. Mishra, M. H. Tyeb, A. K. Majumder

Roping in hydrocyclones is a well-known phenomenon in mining and mineral industries which put serious restrictions on their continuous and maintenance free operation. Roping is mostly observed in association with high underflow solid concentrations which can be attributed to higher fraction of solids reporting to the underflow or the feed solid concentration itself being higher. This paper proposes a newly designed spigot with a truncated conical geometry which can allow for a rope-free discharge at higher feed solid concentrations. The experimental observations revealed that in the operation of a 50.8-mm-diameter hydrocyclone, roping ensued at 10% to 12.5% (wt%) feed solid concentration depending on feed inlet pressure for the cylindrical spigot, whereas with the modified spigot, rope free discharge was attained even at 25% (wt%) feed solid concentration.

Jan 8, 2022

By C. B. Manula, R. L. Sanford, R. A. Rivell

A - Contains the coordinate pair information for deriving the co¬efficients of the 3rd degree polynomial which approximates the loading station equation. C(N) - Coefficients for third degree approximating polynomial. I - General DO LOOP variable. K - Position in BRANCH of next character. L - Format specification in DEFINE FILE statement. X - Uniform displacement for random uniform number. Y - Load increment At. AO-A3 - Coefficients of approximating polynomial for loading station equation. GR - Grade direction, or grade resistance. IQ - Counts quadruples of distance grade speed and end of route for determining total distance. IT - Intersection counter in XXXDEF. Il - Station number trip is leaving. Jl - Station number for trip destination. J2-J8 - Motor assignments and functions for given trip. KK - Location of starting grade and distance in DISTGR KK - Position of decimal point in real number. KZ - DO LOOP variable for motor assignment check. LL - Location of ending grade and distance in DISTGR. Ll - Position in IECB of station satisfied. L3 - Next available position for IECB sort. MM - Flag for printing the failure of sanding to overcome slippage. NN - Trip destination in MOTSER RR - Rolling Resistance. XK - Station level or type.

Jan 1, 1974

By J. L. Ellenberger, G. S. Esterhuizen, T. Miller, M. M. Murphy

A limestone mine in Ohio has had roof instability problems that have led to massive roof falls extending to the surface. This paper describes a collaborative study of these events undertaken by the National Institute for Occupational Safety and Health and the mine owners. The study focuses on the roles that weak, moisture-sensitive floor and weak bands in pillars play in a general instability that led to roof falls at this mine. The NIOSH Stone Mine Pillar Design software (S-Pillar) does not include analysis for weak floor or weak bands and recommends that when such issues arise they should be investigated further using a more advanced analysis. It is important to recognize that without the impact of the floor or weak bands, the calculated inherent stability factor for these pillars is within the recommended design range. Therefore, to further investigate the observed instability occurring on a large scale at the Ohio mine, FLAC3D numerical models were employed to help determine the failure mechanism. Roof-to-floor convergence monitors were also installed in the areas predicted to have further instability. This case study will provide important information to limestone mine operators regarding the impact of weak floor causing the potential for roof collapse, pillar failure, and subsequent subsidence of the ground surface. This recent case demonstrates that weak floor can be a significant factor in pillar stability and should be assessed during the design stage of the mine.

Jan 1, 2015

By Hugh M. Roberts, R. D. Longyear

Introduction ............................ 27 GEnERal Geology........................... 29 The ORebodY in Western Falco~ridgI TownsRip........... 31 Quartzite-Graywacke Formation................... 33 Greenstone............................ 33 Norite ............................. 33 Metamorphism.......................... 35 The Orebody........................... 36 Mineralogy ........................... 37 Grade of Ore........................... 42 Genesis oF tEe Ores . :....................... 43 Summary of Various Hypotheses.................. 44 Magmatic Segregation by Crystallization of Sulphides........ 44 Gravitational Segregation of Molten Sulphides at the Base of the Magma 45 Intrusion of Molten Sulphides after the Consolidation of &apos;he Nurite.. 45 Deposition by Hydrothermal Solutions.............. 46 Magmatic Segregation by Extraction from Crystallizing Norite... SO The Relationship between the Exploration and Theories of Origin .... 50 Volume Relations of Norite and Sulphides............... 62 Intimate Association of Norite and Sulphides............. 53 Granitic Material........................ 54 Uniform Content........................ 54 Sulphides in Walls......................... 54 Absence of Typical Hydrothermal Minerals.............. 55 SUmmaRY................................ 56 Introduction During 1916 and 1917. the E. J. Longyear Co. of Minneapolis. Minn., carried out a campaign of exploration for nickel-copper ore in the Sudbury District of Ontario. The work was initiated by W. E. Smith. a resident of Sudbury. who called the attention of W. J. Mead. Chief Geologist

Jan 1, 1918

NEW MEMBERS The following list comprises the names of those persons who became members during the period July 10, 1919, to August 10, 1919. BALL, C. LEONARD.. Cons. Engr., Suffern Co., Inc., 135 Broadway, New York, N. Y. BARRY, CHARLES W Box 502, Idaho Springs, Colo. BATTLE, JOEL ALLAN, JR., Min. Engr., U.S. Bureau of Mines, Room 2114, Interior Bldg., Washington., D. C. BEER, GUIDO, Compagnia. Italian, Dir Bronzi Speciali, C. I., B. S. La Direzione, Italy. BITLER, WILLIAM F., Management of Coal Properties, The Provident Life & Trust Co. of Philadelphia, 409 Chestnut St., Philadelphia, Pa. BLOOM, SETH W., Chief Engr,, Northwestern Min. & Exchange Co., 130 E. Sribner Ave., Du Bois, Pa. BOYDELL, W. Guy B., Min. Engr., Tul Mi Chung Mine, Care Seoul Min. Co. Whang Hai Do, Chosen. Korea. BRYAN, RUSSELL R.., Met., Sunnyside Min. & Mill. Co., Eureka, San Juan Co., Colo. CHIAPELLA, STEPHEN EUGENE 323 W. 30th St., Los Angeles, Cal. CONWAY, EDMUND JOHN, Exploration Engr., Granhy Consolidated Min., Smelt & Power Co., Ltd., Anyox, B. C., Canada. DEMOREST, DANA J Prof. of Met., The Ohio State Univ., Columbus, Ohio. EIDEMILLER, H. N., Geol., Benjamin C. Neely, Min. Lands & Leases, Crystal Falls, Mich.

Jan 9, 1919

By Cyril Wells, Robert F. Mehl

The two earlier papers in this series1,2 presented data on the rate of diffusion of carbon and of manganese in gamma iron. Apart from their scientific interest, these data are needed chiefly in order to treat data on carburization, on rate of formation of pearlite, and on rate of austenit-izing in a quantitative way.1&apos;2&apos;9&apos;10 In the present investigation rates of diffusion of nickel in ?-Fe over wide temperature and concentration ranges have been determined, and the effects of carbon, of im- purities, and of grain size on these rates have been studied. Claussen,3 using the data of Fry,4 has calculated the diffusion coefficient of nickel in y-Fe as 9.2 X 10-11 sq. cm. per sec. at 1200ºC., but had no data from which to calculate the variation of D with concentration, temperature, and percentage of carbon. Method and Materials Method.—Nickel was diffused along the axis of a cylindrical specimen across a concentration gradient, concentration-penetration curves were determined and D values calculated from Grube or Matano solutions.5 Details of the method are given

Jan 1, 1941

By Cyril Wells, Robert F. Mehl

The two earlier papers in this series1,2 presented data on the rate of diffusion of carbon and of manganese in gamma iron. Apart from their scientific interest, these data are needed chiefly in order to treat data on carburization, on rate of formation of pearlite, and on rate of austenit-izing in a quantitative way.1&apos;2&apos;9&apos;10 In the present investigation rates of diffusion of nickel in ?-Fe over wide temperature and concentration ranges have been determined, and the effects of carbon, of im- purities, and of grain size on these rates have been studied. Claussen,3 using the data of Fry,4 has calculated the diffusion coefficient of nickel in y-Fe as 9.2 X 10-11 sq. cm. per sec. at 1200ºC., but had no data from which to calculate the variation of D with concentration, temperature, and percentage of carbon. Method and Materials Method.—Nickel was diffused along the axis of a cylindrical specimen across a concentration gradient, concentration-penetration curves were determined and D values calculated from Grube or Matano solutions.5 Details of the method are given

Jan 1, 1941

NEW MEMBERS The following list comprises the names of those persons who became members during the period June 10, 1919, to July 10, 1919. ANDERSON, JOHN EDWARD, Min. Engr., Lehigh Valley Coal Co., 121 N. Laurel St., Hazleton, Pa. BENBOW, B. L., Mgr., Cleveland Wire Division, National Lamp Works, General Electric Co., 1770 E. 45th St., Cleveland, Ohio. BLAIR, CHARLES S., Geol., Tennessee Coal, Iron & R. R. Co., Birmingham, Ala. BOLAND, FRED L., Chief Draftsman, Mine Dept., Chile Exploration Co., Chuquicamata, Chile, South America. COLLIER, OTTO L., Civil & Min. Engr., Secretary, Ernest M. Merrill Engrg. Co., Mullens, Wyoming Co., W. Va. DELAMATER, GEORGE RICHMOND, Asst. Supt:, By-product. Coke Oven Dept., Steelton Plant, Bethlehem Steel Co., Steelton, Pa. DOELL, WILLIAM R Chief Engr., Mahuomen Iron .Co., Crosby, Minn. ENDO, SHINZO 365 Komagome Shimmeicho, Hongo, Tokio, Japan. EVANS, CHARLES E., Chief Draftsman, American Smelt. & Refin. Co., Murray, Utah. FISCHER, OSCAR A 62S First National Bank Bldg., Denver, Colo. FISHER, GEORGE KINGSBURY, Met. Engr 47 Baker St., Saranac Lake, N. Y. FRAZEE, VERNE, Min. Engr Moweaqua, Ill. FURNICHI, ROKUZO, Supt. of Min. Dept., Besshi Copper Mine, Baron Sumitomo Co. Ehime Japan

Jan 8, 1919

By Aiyuan Ma, Tu Hu, Chenyu Sun, Yonggang Zuo, Hongying Xia, Jinhui Peng, Libo Zhang, Yongguang Luo

"In this study, the adsorption characteristics of tannin acid in aqueous solution were investigated using regenerated activated carbon (AC), with the aim to remove the tannin acid organic matter from the solution after zinc hydrometallurgy and Ge precipitation. Results showed the temperature has little effect on the adsorption ability (q.) of the regenerated activated carbon. The experimental equilibrium data were tested for the Langmuir and Freundlich isotherms. The adsorption equilibrium was better described by the Langmuir isotherm (R2 > 0.99). Pseudo first- and second-order kinetic models were used for describing kinetic data. It was determined that the kinetics of tannin acid removal was well fitted by second-order reaction.IntroductionGermanium recovery is a complex processes [1]. Hydrometallurgical processes are favoured and these are based on the precipitation of germanium as hydroxide or sulphide or alternately with tannic acid [2]. However, in the germanium recovery process, too much tannin is consumed by the germanium-tannins complexation process, and results in a high content of tannic acid remaining in solution, which is harmful to the valuable metal recovery [3]."

Jan 1, 2014

By Leonardo F. Trivino

Despite the significant economical and safety implications of poor blasting practice in mining and quarrying operations, the default practice in many large operations, including both design and control, is considerably below standard when compared to other engineering disciplines. Blast dynamics includes a number of complex phenomena, such as the generation, propagation and interaction of stress waves, the expansion of high pressure, high temperature gases from the explosive components, and their combined effects upon the rock mass, including fracturing, fragmentation and displacement. In order to tackle this non-trivial problem, a combined finite and discrete element software (Y-code) capable of accounting for the dynamic behaviour of stress waves, simulating fracturing processes and modeling the expansion of gases is under development. The constitutive models used in this particular software are fundamentally simple, however, non-linearity and chaotic behaviour result as natural consequences of the interaction of relatively simple processes and mechanisms, such as propagation of stress waves in the immediate vicinity of the exploding borehole, and the creation and propagation of fractures. Advances on its development and comparisons with experimental data show realistic propagation of stress waves and fracture networks.

May 1, 2013

By Knox Van Dyke, Vincent Castranova, Lixin Wu, Mark J. Reasor, James M. Antonini

"One of the proposed mechanisms involved in the pathogenesis of silicosis is that inhaled silica dust activates a ""respiratory burst"" in pulmonary phagocytes, such as macrophages and neutrophils. This increase in oxidative metabolism results in enhanced generation of reactive oxygen species which if produced in excess, would overwhelm natural defense mechanisms and cause damage to the lung parenchyma. This damage would then result in scarring, fibrosis, and decreased gas exchange.Weiss and LoBuglio' have listed several oxygen species produced by phagocytes which may be involved in cellular injury. These oxidants include superoxide anion, hydrogen, peroxide, hydroxyl radical, and hypochlorous acid. Superoxide anion (0;) is generated from molecular oxygen by the plasma membrane bound enzyme NADPH oxidase according to the following reaction:Once generated, superoxide anion can form hydrogen peroxide:In the presence of myeloperoxidase and halide, hydrogen peroxide can form hypochlorous acid:Superoxide and hydrogen peroxide can also form highly reactive hydroxyl radicals. Hydroxyl radicals can be generated slowly by the Haber-Weiss reaction:In addition. hydroxyl radical production can be catalyzed via the Fenton reaction:Hydroxyl radicals can also be generated from the reaction of superoxide and hypochlorous acid as follows:Recent investigations suggest that, in addition to the reactive oxygen species discussed above, nitric oxide may be a potential mediator of silica-induced toxicity.2-4 Nitric oxide (NO') can be generated by the cytosolic enzyme nitric oxide synthase according to the following reaction:NO synthase exists in two forms. i.e.. a constitutive. Ca2+-calmodulin-dependent form and an inducible. Ca2+-calmodulin-independent form. In pulmonary phagocytes. the activity of the constitutive form of NO synthase is low. However. NO synthase can be induced in macrophages and neutrophils by a variety of stimulants such as lipopolysaccharide. interferon y. chemotactic peptide, platelet activating factor, or leukotriene B4.3.5Once generated. nitric oxide can combine with superoxide anion to form peroxynitrite as follows:Peroxynitrite is a potent oxidizing agent. In addition, peroxynitrite can form peroxynitrous acid. which in turn can produce hydroxyl radical and nitrogen dioxide (all of which exhibit strong oxidizing potential) by the following reactions:Oxygen metabolites have been shown to cause lung damage in vivo.6 Such damage includes edema. leakiness of the alveolar endothelial/epithelial barriers, and airway constriction.7 Superoxide and hydrogen peroxide have been associated with membrane damage and cell lysis.8 These oxidants have also been associated with alteration of cytoskeletal structures at cell-cell junctions and elevation of transepithelial conductance in cultured monolayers.9 Macrophages or neutrophils can be stimulated by bacteria or phorbol myristate acetate to produce sufficient oxidant levels to lyse lymphoma cells.10 This cell killing is inhibited by catalase but is unaffected by superoxide dismutase. hydroxyl radical scavengers. or azide. i.e., an inhibitor of peroxidase. This implicates hydrogen peroxide as the active oxidant. Similarly. Weiss et al.11 have reported that hydrogen peroxide is critical in the death of cultured endothelial cells due to neutrophil activation. In addition. hydroxyl radicals generated by monocytes have been associated with cell injury.12 Lastly. peroxynitrite has been shown to oxidize sulfhydryl groups and to inactivate proteinase inhibitor making the lung more susceptible to damage caused by phagocytotic enzymes.' Therefore. a strong case can be made that activated pulmonary macrophages and neutrophils are capable of causing oxidant injury. This chapter presents in vitro and in vivo data indicating that silica is associated with the production of reactive oxygen species from these pulmonary phagocytes."

Jan 1, 1998

By K. L. Ford, D. R. Lentz, J. H. Rickard, R. P. Taylor

Abstract - Coupled gamma-ray spectrometric and lithogeochemical studies throughout the Heath Steele Mines area, Bathurst Camp, New Brunswick, indicate that primary and secondary geochemical differences exist between the stratigraphic footwall and hangingwall crystal tuff units which host the massive sulfide deposits. Of particular interest is Th, and to a lesser extent, Zr and Y, which are more concentrated in the hangingwall than the footwall crystal tuffs, whereas the opposite is true for TiO2. This expands on earlier lithogeochemical-chemostratigraphic results concentrated in the eastern part of the Heath Steele belt that led to revision of the local stratigraphy, and necessitated a structural re-interpretation of the area with implications for exploration. Although K depletion (decreased K and K/Th) is typical of chloritized footwall zones of chloritization, these features were not fully apparent here due to the recessive nature of these altered zones. In situ radiometric analysis using a portable gamma-ray spectrometer is a rapid, inexpensive analytical technique for chemostratigraphic characterization of rock units within volcanogenic massive sulfide deposit settings, provided there is a contrast in the distribution of natural radioelements, particularly Th and K.

Jan 1, 1998

The hoisting system at the Newcrest Telfer mine is designed for a final duty of 7.35 million tonnes per annum at a hoisting distance of 1450 m. In terms of hoisting capacity (t/h) times hoisting distance it is one of the largest friction hoist installations. Initially, the hoist will be equipped for hoisting 6.5 Mtpa from 1100 m depth. This new drive technology is now well proven by ABB for mine hoist applications with the first installation in commercial operation since July 2001. To date 17 systems for medium voltage drives and another five for low voltage drives have been purchased from ABB for mine hoists. This paper will also deal with skip design and powerful data loggers with diagnostics for local and remote monitoring that are installed in the Telfer mine hoist.

Jan 1, 2005

By R. C. Reed, L. T. Wu, H. C. Harada, K. Kawagish, R. T. Wu

Oxidation of pure metals is a chemical reaction in which the metal loses one or more electrons, such that the atom of the metal changes from the neutral state to a positively charge ion and reacts with oxygen to form an oxide of the metal. The oxide can form as a protective and adherent scale that slows down further oxidation, or may spall off repeatedly, exposing fresh metal surface to react with oxygen. In multi-component alloy systems such as typical high temperature NiCrAlY bond coats, more than one oxidation mechanism may take place at once and thus, complicates the study of oxidation. To better understand the competition between formations of oxides of different compositions, a thermodynamic assessment is carried out to study the oxidation mechanism of a Ni-27Cr-9Al (at %) ternary alloy. Based on the assessment, it is demonstrated that the layering of different oxides can be determined, with the most stable oxide (alumina) existing directly above the metal-oxide interface and the least stable oxide (nickel oxide) locating on the outer most layer. A comparison between the calculated results and previously published experimental observations shows excellent agreement.

Jan 1, 2010

By John A. Richards

This paper is one of a series being published by the Bureau of Mines on mining methods and costs. It describes briefly the manner in which slusher hoists and scrapers are used in connection with clock-caving methods at the Emma Nevada mine of the Consolidated Coppermines Corporation, Kimberly, Nev. Kimberly is in the Robinson mining district, White Pine County, 7 miles west of Ely. The district is served by the Nevada Northern -Railroad, which branches from the main line of the Southern Pacific at Wells, Nev., 140 miles north, Paved U. S. Highway 50 from Salt Lake City, Utah, to Reno, Nev., passes through Ely. The altitude at the collar of the Emma Nevada shaft is 7117 feet. The surrounding hills are covered with a sparse growth of juniper, pinon, and mountain mahogany.

Jan 1, 1940

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