Search Documents

By John B. Cocanour

The U.S. Bureau of Mines (USBM) has developed a laboratory-scale on-line analysis and process control system for a decopperization electrolytic circuit. This system is software driven, running on a 486DX-33 personal computer (PC) utilizing a portable energy- dispersive x-ray fluorescence (XRF) spectrometer as the sample analyzer. The XRF copper reading obtained was used as the control variable through an RS-232 serial interface to the PC for software-based control of feed flowrates. When the copper concentration in the electrolytic cell (as measured by the XRF) deviated from the set point, the feed flowrate to the cell was automatically altered using software-based proportional-integral-differential (PID) computer control to yield the desired copper concentration at the electrolytic cell outlet.

Jan 1, 1994

Supergene nickel sulphide ore mined currently by Agnew Mining Company is at times partially oxidised to sulphate. The resulting soluble nickel, and calcium and magnesium in mill water, are shown to act as depressants in flotation. The depressant effect is favourably selective in that violarite, the main nickel mineral, is less affected than pyrrhotite. Nickel recovery, however, is adversely affected, probably through reduced flotation of complex sulphides. Soda ash consumption is increased markedly by the presence of the cations as shown by operating data and pulp titration tests. A significant increase in concentrate grade, from 9% to 14% Ni, was achieved late in 1981. One of the changes in plant practice which contributed to this improvement was the addition of soda ash to mill feed rather than to flotation feed as before. It is shown by laboratory tests that this reduced the depressant effects of the cations, thereby improving recovery at the expense of rougher selectivity, or equivalently, increasing concentrate grade at constant recovery. The selective depressant effect cannot be exploited until scavenger recovery is improved and a scavenger concentrate regrind-retreat äcircuit is implemented. Development is

Jan 1, 1978

By Joaquin Ruiz

Naica consists of at least 10 mantos and 40 chimneys that have produced over 15 million tens of ore with 10% Zn, 13% Pb and 13 oz/ton Ag. The ore occurs in thick-bedded, folded Cretaceous limestone. Fractures and 26 Ma old felsite dikes with an initial strontium isotopic ratio of 0.708 localize the mineralization. The mantos follow the dikes and have abundant early skarn with manganohedenbergite, calcic garnet, idocrase, quartz, calcite, wollastonite, schellite and later sulfides. The chimneys arise from the mantos and change from silicate-rich to silicate-free sulfide limestone replacements. Carbon, oxygen and sulfur isotope data on carbonates, silicates, sulfides and sulfates are compatible with a single evolving (magmatic?) fluid.

Jan 1, 1985

By N. L. Piret

Primary and secondary copper smelting dusts are being generated in varying quantities with very dissimilar characteristics due to the different compositions of feed materials and the type of process utilized. After categorizing the multitude of dust types, the criteria for on-site and off-site recycling of smelter dust in terms of type and concentrations of the accompanying elements are established. Thereby, consideration is given to the important aspects of: ? optimization of copper recovery ? quality of copper product ? valorization of accompanying elements ? elimination and disposal of deleterious impurities ? minimization of impact on operation ? effects on operating costs ? environmental impact of dust treatment on overall process Existing commercial, emerging and proposed copper smelting dusts, pyrometallurgical as well as hydrometallurgical, treatment schemes are reviewed and evaluated technically, economically and environmentally in an attempt to streamline the vast number of proposed options. Thereby, the high selectivity achievable in hydrometallurgical dust processing due to it being complementary to the smelting process is expected to be given increased consideration.

Jan 1, 1995

By Joseph Matoney, B. K. Parekh

INTRODUCTION The term "dewatering" refers to removal of water from coal. Water associated with coal can be categorized as "free or surface" and "inherent or chemically bound" moisture.' The free moisture is found on the surface of coal, in capillaries and small spaces between two or more particles. The inherent or chemically bound water is found in the interior of the coal and as part of coal structure. A significant amount of free moisture can be removed by mechanical dewatering techniques. However, inherent moisture can only be removed by applying energy intensive techniques, e.g., direct or indirect heating. Moisture in the coal offsets some of the benefits of coal cleaning. Extra water in clean coal adds to extra cost in transportation, heat lost during vaporization, and plugging of chutes. From a utility perspective, a 1 % increase in moisture can offset a 4.5% decrease in ash.2 Mechanical dewatering can be classified into two major process categories according to the principles involved, namely, 1. Sedimentation-liquid is constrained and particles move freely. 2. Filtration-particles are constrained by a medium and the liquid flows through. Each of the process categories is composed of various separation techniques shown in Fig. Equipment currently being used by the mechanical dewatering of coal of varying size ranges and final moisture content is illustrated in Fig. 8-2. This figure indicates that sizes larger than 13/, in. (37.5 mm) present no particular dewatering problem. Shaker screens of the very crudest types and designs are capable of producing these sizes at low surface moistures. High-speed vibrators are used for the intermediate sizes and can be used for smaller sizes down to 0.02 in. (0.5 mm) if high moistures (15% surface moisture or greater) can be tolerated in the product. Usually, however, the vibrator is not used below 3/, to 3/, in. (9.5 to 6.3 mm) because of the moisture associated with these fine sizes. At this level, centrifugal force is usually employed to aid dewatering. Centrifuges of various types and designs are used practically

Jan 1, 1991

By D Hunter

A production information management system (PIMS) was recently implemented at Queensland NickelÆs Yabulu Refinery. Although a strong business case was developed to justify the significant investment in PIMS some potential beneficiaries remained sceptical of the anticipated benefits. The decision to install PIMS was justified as the on-line availability of continuous production data enabled the optimisation of some crucial operations resulting in significant cost savings, improved throughput and final product quality. Furthermore the rapid access to extended historical data has allowed the cause of repeated failure of equipment to be determined. The investment is expected to pay for itself within two years and has already contributed towards significant savings. This paper focuses on some of the diverse production improvements gained and compares the anticipated benefits in the business case to those achieved. A brief outline of the phased implementation of the OSIsoft PI data historian and complementary client software at Yabulu is included, along with details of the lessons learned.

Jan 1, 2003

By Rafael Abreu Fraga

Em qualquer novo investimento, o desafio é ter um projeto com uma fábrica com flexibilidade para produzir uma ampla gama de produtos de alto valor agregado para atender a demandas futuras dos setores de energia, naval, construção e equipamentos pesados. O emprego de equipamentos robustos com elevado nível de automação é fundamental para isso. Um componente chave é a utilização da laminação totalmente automática através de modelos físicos integrados com o controle dos equipamentos e das temperaturas de processo objetivando alcançar patamares diferenciados de produtividade e qualidade. Este trabalho visa apresentar os novos recursos técnológicos incorporados a nova linha de Laminação de Chapas Grossas da Gerdau em Ouro Branco/MG.

Aug 17, 2017

By R. R. Oder, R. E. Jamison, E. D. Brandner

This paper presents the preliminary test results obtained using a 0.38-kg/s (3,000-lb/hr) beta prototype MagMill. In processing Upper Freeport coal, the beta prototype recovered 82 % of the weight of the feed and 91 % of the heat content while reducing the potential emissions of sulfur by 61%. Pyritic sulfur in the MagMill product was reduced by 78% compared with that in the feed. For all runs, the mill product particle size was controlled to between 70% and 80% -741m (200 mesh). Recoveries of mercury, arsenic and selenium ranged from 35% to 45% of the amounts found in the feed. Power draw was reduced by 26%, and mill throughput was increased by 9% compared to the pulverizer operating with no magnetic separator attached.

Jan 1, 2002

By Greg Nutson, Jeremy Butkovich, Bill Perkins, Hollie Ellis, Paul Bott

"Dynamic soil-structure interaction (DSSI) analyses are becoming more common in bridge designs, especially in seismically active areas. Because of its proximity to two active fault zones, the Evergreen Point west approach bridge replacement will be base isolated, and will be designed using DSSI. The project team completed two independent bridge designs to satisfy peer review requirements. The designs required substantial characterization of the soil dynamic behavior using both laboratory and in-situ testing. The analyses made use of earthquake time histories spectrally matched to conditional mean spectra. This led to reduced, and more realistic seismic demands on the structure, compared to conventional uniform hazard spectrum matching. The bridge analyses suggest that the preliminary bridge design is relatively conservative. This will allow the design team to potentially reduce shaft/column diameters and reinforcement. The design team estimates that the dynamic analysis design could represent a net savings of around $60 to $90 million compared to a conventional design.INTRODUCTIONThe Evergreen Point Bridge conveys State Route (SR) 520 2.6 miles (4.2 kilometers [km]) from Seattle to Medina across Lake Washington. The bridge is located in a seismically active area, and the Washington State Department of Transportation (WSDOT) has determined that the western half of the 1960s-era bridge (the “west approach”) is vulnerable to earthquake damage. WSDOT has begun preliminary design to replace the west approach bridge.The west approach extends about 6,100 feet (1,900 meters [m]) east from Seattle’s Montlake neighborhood, over Union Bay and Foster Island, then into Lake Washington proper (Figure 1). Approximately 5,600 feet (1,700 m) of the replacement bridge would be constructed over water. Subsurface conditions along the bridge alignment consist of 5 to 80 feet (2 to 24 m) of very soft peat and clay, over very dense/hard sand and clay. Multiple pile supported columns support the existing bridge. The new bridge would be supported by 8- to 10- foot-diameter (2.4 to 3.0 m) drilled shafts that extend about 50 feet (15 m) into the underlying very dense/hard soil. To reduce seismic demands on the bridge superstructure, WSDOT has decided to incorporate a base-isolation system into the bridge design."

Jan 1, 2017

By P. Favreau

"This paper describes the progress accomplished at the Noranda Technology Centre in the field of three-dimensional computer-aided underground blast design. Traditional methods of laying out underground blasts are reviewed, and the new computer-aided approach is described. Time savings achieved through the use of BLASTCAD can be advantageously used to better engineer blasts, using models and blast vibration analysis. Future work involving the attachment of blast models directly to the system is also addressed.IntroductionThe Noranda Technology Centre's (NTC) Environment and Mining Laboratory, in cooperation with the mining operations of the Noranda Group, is committed to the development and implementation of new technologies in the field of mineral extraction . Within the frame of its research program, the Blasting Technology Program is developing computer "" tools"" designed to assist the blasting engineer or technician. These computer "" tools"" are regrouped under a global software system called BLASTCAD.The BLASTCAD project started in 1990 at NTC. At that time computer programs designed to calculate and model various blasting parameters had been accumulated. These programs cam e from different sources and were mutually incompatible. Furthermore, they were developed as research programs with tittle effort spent on user interface. These programs are very useful, but are highly specialized, need large input files and can be quite tedious to use as ""standalone"" packages .Therefore, the situation being faced was one where all these programs were available at the Noranda Technology Centre, but not a t the operations. The two following options were then considered: 1. continue to run all the models and programs at the Noranda Technology Centre, and present results through reports to the mines, or2. regroup all the different programs under a single one that would make them share the same data base and be transported to the user. This second option is the one that was adopted; the result is BLASTCAD."

Jan 1, 1993

By B. C. Legg, G. L. Tiley

"Many of the ore bodies presently being developed are in remote locations and are, or will be, served by electrical power supply systems of limited capacity.The largest single components of the electrical systems of an underground mine are usually the production hoist drives; the power demands of these drives vary continuously throughout each hoisting cycle.Before 1970mine hoists were driven by either wound rotor induction motors or DC motors in conjunction with motor generator sets.Static Power conversion equipment now costs less to purchase and install and is claimed to be more efficient than motor generator sets. On the debit side, however, it can adversely affect the hoist motors, it operates at relatively low power factors, and it produces harmonic currents.This pa per discusses the effects of static equipment on both DC motors and AC power systems, and evaluates the relative consumption of the three classes of drives."

Jan 1, 1993

By E. P. Youngman

At the time of the preparation of the monograph upon the mining legisla- tion of Newfoundland, by the Imperial Institute of London, the existing local statutory law (as distinct from case laws and the applicable English acts) con- sisted of the following legislation: 1. Chapter 129 of the consolidated statutes, entitled "Of Crown Lands, Timber, Mines and Minerals," as amended by the Crown lands act, 1928. 2. Chapters 131 and 132 of the consolidated statutes (acts relating to mines regulation and rewards for discovery of minerals, respectively). 3. Crown lands act, 1918, as amended by the crown lands (amendment) act, 1921. 4. The Labrador Act, 1927. 5. The Crown royalties act, 1927. 6. Crown lands act, 1928, together with rules and regulations issued thereunder.

Oct 1, 1932

By James K. Richardson

Today, the enigma of the "missing man" in the metal mining industry equals, and frequently surpasses in objective importance, the problems of ore development, drilling, sampling, pumping, milling techniques, geophysical prospecting, or any one of a hundred highly technical subjects. Unfortunately, as engineers, we have confined our attentions, in the main, to the scientific phases of mineral technology, relegating our man power problems to the background. But what good has all our scientific study and preparation been if we can't get the ore mined, milled, or smelted? What has happened to our labor supply? Where is the good old miner who could timber, drill a round, lay track, or do any job underground?

Jan 1, 1949

By L. Paulino, C. E. Zangiacomi, J. Yamamoto

"This paper presents the learning from Alcoa Po9os de Caldas Smelter in Brazil, after several energy restrictions resulting from the failures of three rectifier units at its power switchyard. Starting on December 27th, fuses and diodes failed in three rectifier units of Potline #1, causing a long and dangerous power interruption. Even after current was reestablished, amperage was only 70% of the line target leading to a bath freezing process that lasted for around 48 hours. The process engineering team played with several potroom parameters as pot resistance, bath and metal levels, alumina feeding and bath chemistry in an attempt to minimize impact on the potline metal output and energy consumption. As it will be illustrated, the first battle was to keep the pots running on a ""survival"" approach. After that, several changes took place on the procedures used to run at reduced current which were considered rather successful. Finally, some recommendations will be given to foresee and prevent transformers and rectifiers from undesirable failures."

Jan 1, 2006

1. New books P. Sarnoff. Trading in gold. Cambridge, Woodhead- Faulkner, 1980. 136 pp. £3.50 by airmail. Environmental Planning Professions Interdisciplinary Committee (EPPIC). Proceedings: Joint EPPIC/Habitat Symposium: Shaping Our Environment. Johannesburg, EPPIC (P.O. Box 61019, Marshalltown 2107), 1980. R3 per set of 2 issues. H. P. Patra and K. Mallick. Time-varying geoelectric sounding. Amsterdam, Elsevier, 1980. 420 pp. D.S. $87.75. Die Suid-AfrikaanseSteenkoolverwerkingsvereniging. Steenkoolvoorbereidingskursus. J ohannes burg, die Vereniging, 1930. 335 pp. Members of Chamber of Mines of South Africa R15, nonmembers R40. D. R. Derry. A concise world atlas of geology and mineral deposits. London, Mining Journal Books, 1980. HO pp. £26.25 byairmail. 2. Journal Remote sensing of environment (RSE). 3. NIM reports Report No. 2064 The on-line monitoring of gold in barren solutions. Report No. 2065 The determination, by X-ray-fluorescence spectrometry, of gold, silver, and base metals on activated carbon. Report No. 2068 The determination of platinum, palladiuim, rhodium, and gold in ores and concentrates by the fusion technique with lead as the collector. Report 2061 The determination, by anodic-stripping voltammetry, of copper and lead in silicate reference materials. Report 2062 The reduction by computer of photoplate data obtained by spark-source mass spectrornetry. Report 2071 The determination, by X-ray-fluorescence spectrometry, of tin and tungsten in scheelite and ca8siterite ores and concentrates. Tunnelling Tunnelling '82, the third international symposium in the series, is being organized by the Institution of Mining and Metallurgy, with the co-operation of the British Tunnelling Society, the Institution of Mining Engineers, and the Transport and Road Research Laboratory.

Jan 1, 1980

By J. A. M. Cano

An extensive research work was developed by Samarco Mineracao S/A to study the quality characteristics of blast furnace pellets produced with high content of MgO. Comparative blast furnace simulation tests were conducted both in Samarco and foreign laboratories. The objective was to evaluate the behavior of high MgO and normal Samarco pellets in the blast furnace operation. Additives such as dolomitic hydrated lime, dunite and magnesite were used for increasing pellet MgO content. The test results showed that pellets produced with high MgO content are similar in quality to normal Samarco Pellets.

Jan 1, 1991

The Goodman Mfg. Co., Chicago, builders of underground electric mining machinery, celebrated its 50th Anniversary on April 23rd. The company has a complete line of cutting machines, loaders, conveyors, locomotives, and shuttle cars for service in both coal and metal mines. The Joy Mfg. Co. has received, under the provisions of the Economic Cooperation Administration, an initial order in excess of $1,000,000 for equipment to be used in the mechanization of iron ore mines in France. While the equipment will be used in various privately owned mines, the order was placed through the French Society for the Development of Mechanical Mining. Included in the equipment are the company's recently developed hard rock loaders and shuttle cars. American Brake Shoe Co. has consolidated all operations of its Canadian subsidiaries into one corporation, the Dominion Brake Shoe Co. Ltd., Montreal, Canada. The products of Dominion Brake Shoe include brake shoes, track equipment, manganese steel castings, automotive brake lining, air compressors, and paint spray equipment. Exhibits of more than 2000 electrical products, processes, and techniques, ranging from precise aircraft instruments to complex working models of steel mill, textile and other industry equipment, will be displayed in the "More Power To America Special" when it makes its nationwide tour this spring. C. H. Lang, Vice-President in charge of sales for General Electric's apparatus department, said that the train will visit the country's key industrial centers for inspection by utility and industrial executives and municipal leaders. The train will be hauled by an Alco¬G-E two-unit, 4000-hp., Diesel-electric locomotive which in itself will be part of the unusual series of displays. Sizing of Excavators and Hauling Equipment. The Power Crane and Shovel Association has released a 24-page bulletin dealing with the proper sizing of excavators and hauling equipment, Technical Bulletin No. 3. Rubber Conveyor Belting. "Installation, Care and Maintenance of Rubber Conveyor Belting" is the title of a booklet just published by the Carlyle Rubber Co., New York. Power Transformers. The manufacturing procedure of Allis-Chalmers small power transformers is described in a new 28-page bulletin, 61B6094A, covering the core and coil unit, no-load tap changer, tank construction, cooling methods, oil preserving systems, bushings, terminal compartments, indicators and testing of transformers. Safety Equipment. General Scientific Equipment Co., Philadelphia, has released a 46-page, fully illustrated catalog on personal protective equipment and industrial safety devices. This new catalog covers respiratory devices, eye protection, hats, gloves, carboy pumps, drum pumps, and miscellaneous safety equipment for use in mines, industries, etc. Osmosalts. The Osmose Wood Preserving Co., Buffalo, N. Y., has issued a bulletin on Osmosalts, the wood preservative which, say the manufacturers, makes timber last three to five times longer, slashes maintenace costs, stops rot, and resists wood-destroying insects. Jigs. The Dorr Co. has acquired the Pan American jigs and they are now known as the Dorrco-Pan American jigs. Originally developed as a gold-saving device for dredges, the simplicity, ease of operation. efficiency, and negligible maintenance of these jigs have resulted in wide adoption on all types of placer operations, in the closed grinding circuits of gold mills, and on many applications where a coarse bed concentrate is separated from the ore gangue.

Jan 5, 1950

By N. Saracoglu, J. P. Golightly, R. H. Wallis, J. J. Brummer

"The McClean uranium deposits are located 11 km west northwest of the Rabbit Lake Mine. Their average grade is 1.8 % U3O8 , and they contain 6. 350 tonnes of uranium oxide in seven pods of variable grade and mineral assemblage. They are hosted by both basal Athabasca Group and the regolith developed on the underlying crystalline basement. The major mineral facies are: sulphide, arsenide, 'bleached', and hematite, with the important uranium minerals being coffinite, uraninite and pitchblende. Abundances of carbon and sulphur isotopes are consistent with their derivation from pyritic graphite in basement gneisses. Isotopes of oxygen and hydrogen suggest equilibration at temperatures of about 200°C. Ar39/ Ar40 age determination of illite associated with ore suggest mineralization began about 1300 m.y. ago and that significant alteration had ceased by about 1170 m.y. ago though Pb/ U data suggest the deposits continued to evolve into the Mesozoic.IntroductionThe McClean deposits lie on the eastern side of the Athabasca Basin of northern Saskatchewan where they are part of a cluster of uranium deposits lying west of Wollaston Lake (Fig. 1). The general stratigraphy is schematically portrayed in Figure 2 which emphasizes that mineralization is hosted by both the Athabasca Group and the underlying regolith and also that the deposits are preserved at depth and have not suffered from preand post-Pleistocene weathering and erosion. This circumstance, combined with their simple shape and the presence of seven separate zones of mineralization (pods) allows a description, based on over 450 fully cored drill holes, to be made of the wide variation in chemistry, grade, alteration patterns and position relative to the sub-Athabasca Group unconformity. Ar39 / Ar40 age determinations have been made of illites associated with regolith, Athabasca Group and mineralization and studies are in progress on C, S, 0 and H isotopes of mineralized material and host rocks. Only some of these data have been published; Brummer et al., (1981); Golightly et al., (1982); Bray et al., (1982); and Saracoglu et al., (1983). The only other published data on McClean geology are by Tremblay (1982, 1983)."

Jan 1, 1986

By James B. Cathcart

The potash mine of the International Minerals and Chemical Corp. is about 18 miles east of Carlsbad, New Mexico, in sec 1 and 12, T 22 S, R 29 E, N.M.P.M. Potash is produced from two zones in the Salado formation of late Permian age. The lower zone, consisting of a mixture of sylvite (KCI) and halite (NaCl), lies at a depth of about 900 ft, and the upper zone, in which the principal potassium mineral is langbeinite (K2SO4 2MgSO4), lies at a depth of about 800 ft. Because of the plastic nature of the material, fractures in the Salado formation are extremely rare and have been noted only on the 800 ft level of the International mine. The open fracture described below is almost unique. Only one other open fracture has been noted, and it was on a working face in the same general area as the one described, but was destroyed before the writer had a chance to examine it. According to J. E. Tong, foreman on the 800 level, this fracture was similar to, but smaller than, the one herein described. The saline strata are nearly flat-lying and comprise interbedded layers of halite, anhydrite (CaSO4), and poly-halite (2CaSO4.MgS04.K2SO4-2H2O), with halite predominating. The halite layers contain local concentrations of sylvite, carnallite (KC1.MgCl2.6H2O), and langbeinite. The principal marker in the potash mines area is a bed of anhydrite about 8 ft thick, and 70 ft below the 800 level. This bed contains varying amounts of polyhalite, and locally a few blebs of sylvite. Two principal marker beds are present over most of the 800 level. The lower is the "Middle Salt Marker," a bed of bright-orange halite, which ranges in thickness from a knife-edge to about 0.6 ft, and is usually bounded above and below by thin seams of green or reddish-brown clay. In langbeinite-rich areas, this marker usually contains abundant blebs of langbeinite. The upper of the two principal markers is a green clay seam, containing abundant halite, which ranges in thickness from 0.1 to about 0.5 ft. It is 2 to slightly more than 5 ft above the Middle Salt Marker. No langbeinite of minable grade is found above this clay, and it

Jan 1, 1950

By George S. Rice

GROUND movement and subsidence is an important matter from several points of view and it is regrettable that more papers have not been written on this subject in the past year. Damage may be done to surface buildings or to the higher workings of a mine, and a study of the subject gives valuable in- formation on hanging-wall or roof control. The latter objective is strikingly shown in a recent paper presented by Jack Spaulding on Oct. 21, 1937, before the Institution of Mining and Metallurgy, of Great Britain, entitled "Theory and Practice of Ground Control in the Kolar Gold Field, India." All may not agree with some of his theories that were deduced from studies of the many violent rock bursts at depths of 5000 to 7000 ft., but the data obtained are of great value. His theories of symmetrical ring stresses and symmetrical domes which are pictured as perfect are rather hard to understand as such uniformity is un- likely in view of the irregularities in the formation due to folds and fractures of various kinds. All will agree in principle with this idea of domal effects, which have been observed in many countries, but they are generally irregular.

Jan 1, 1938