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By V. H. Gottschalk

Sponge iron is a product resulting from the reduction of an iron oxide below the temperature at which the product melts. Commercial grades usually contain 80 to 95 percent metallic iron, 2 to 5 percent unreduced iron oxide, and an amount of siliceous gangue material depending on the pur.ity of the are used for reduction. The reducing agent may be gaseous or solid, and a large variety of procedures have been proposed for bringing the reducing agent into reaction with the iron oxide. Of the proposed procedures, the one that has the distinction of having been in continuous commercial operation for the longest time, from 1911 to date, was developed at a ceramic plant in Hoeganaes, Sweden, and yields? a product that has an enviable reputation as furnace feed wherever special, high-quality steels are made.

Jan 1, 1948

By A. R. Barnes, N. Stubina

Increasingly, gold producers are forced to treat ever more refractory ores. While ores containing pyrite, arsenopyrite and carbonaceous material have been subjected to complete pressure oxidation (PDX) as the standard process for such ores, recent improvements in fluid bed roasting technologies have led to a resurgence of interest in roasting as a viable alternative. The lower capital and operating costs of roaster installations add further impetus to this trend. The Extractive Metallurgy Group at Xstrata Process Support operates four fluid bed reactors of various sizes which have been utilised on a large number of projects to treat highly refractory ores. Preliminary mineralogical modelling of both the physical and chemical aspects of the roasting process and subsequent testing under carefully controlled conditions has allowed clients to obtain gold recoveries approaching or matching those achievable by PDX. The flexibility of the units to operate in various modes- " bubbling bed", circulating bed, two stage, sub-stoichiometric and combinations of these, and the range of sample sizes accommodated, from a few kilograms to a few tons, has enabled XPS to accommodate clients with a wide variety of gold bearing refractory ores from all over the world. This paper outlines the key challenges of fluid bed roasting of refractory gold ores, describes the methodology used to design the testwork program and provides some results from select test campaigns.

Jan 1, 2011

By Steve Kral

The mining industry in Colorado faces the same problems the industry faces throughout the United States and the world — record low commodity prices and increasing regulatory and environmental restrictions that seemed designed to curtail mining activities. Despite those obstacles, the mining industry in Colorado still contributes about $8 billion annually to the state’s economy in the form of base and precious metals, industrial minerals, coal and associated service businesses and jobs. So the 300 attendees at the102nd National Western Mining Conference felt reason-ably positive about the industry in their state. The meeting is the Colorado Mining Association’s annual conference and was held at the Broadmoor Hotel in Colorado Springs in November. The theme was “Mining in the New Millennium — Achievement + Innovation = Survival.” Experts from Colorado’s mining industry and abroad discussed the challenges faced by the mining industry as it enters the new millennium. They offered insights into how the industry will operate during the early years of the 21st century and how it will survive low prices and increased regulatory restrictions.

Jan 1, 2000

By John B. Ivey

This is a geologic study of the U.S. Bureau of Mines Oil Shale Tract in the Piceance Creek Basin of Rio Blanco County, Colorado for the preparation of a set of detailed surface geologic maps, measurement and identification of joint attitudes and frequencies, and the classification and mapping of the soils of the area.

Jan 1, 1978

By D Craw, L C. Kerr, P Wopereis

Gold placers in the Nokomai and Nevis valleys are dominantly Quaternary in age. They occur mainly in western tributaries of the upper Nevis, eastern tributaries of the middle and upper Nokomai, and in the trunk valleys themselves. Placer gold in both valleys is dominantly a-phase Au-Ag-Hg alloy. Au-Ag alloy is absent or rare in most of the deposits, except in the lower Nokomai. Alpha-Au-Ag-Hg alloy is typically coarse-grained (up to 2 cm), angular, and rarely flattened or folded. Crystalline texture, quartz intergrowths, and psuedo-hexagonal crystal-pluck cavities are common. Fluvial transport distance predicted from the maximum Flatness Index ofAu-Ag-Hg alloy particles is typically less than 10-20 km. Coarse (up to 2 cm) cinnabar is commonly associated with the Au-Ag-Hg alloy, and both were probably derived from hydrothermal sources in western tributaries ofthe upper Nevis and eastern tributaries of the upper Nokomai. Minor secondary Au-Ag-Hg alloy occurs locally in the lower Nokomai, where it coats or cements detrital a-phase Au-Ag-Hg and Au-Ag alloy particles. Au-Ag alloy dominates over Au-Ag-Hg alloy in the lower half of the lower Nokomai alluvial plain and gravel of a raised channel incised into semischist basement adjacent to the plain. The Au-Ag alloy is rounded and commonly flattened and folded. Crystalline texture, quartz intergrowths, and pluck cavities are rare, and a fluvial transport distance of 25-40 km is estimated from maximum Flatness Index ofAu-Ag alloy particles. The Au-Ag alloy, three types of gamet, magnetite, clinozoisite and well foliated schist boulders in the abandoned channel are not found in the pumpellyite-actinolite facies bedrock in the Nokomai. These components were derived from greenschist facies schist and sedimentary sources in Otago, many tens of kilometers north of the Nokomai catchment. They were transported to the Nokomai either in Wakatipu Glacier till or fluvio-glacial outwash that entered the valley via Nokomai Saddle, the confluence with the Mataura, or both.

Jan 1, 2000

By M. Craig Miller

As the trend continues in the U. S. toward inceased capital investment in longwall mining equipment and wider panels. the risk also increases for gotential financial and production loses due to undetected geologic anomalies. This paper describes how RIM Sm (Radio Imaging Method) is utilized in conjunction with more traditional exploration and interpretive methods to delineate fluvial channels. displacement faults and poor roof conditions in a Southeastern Ohio coal mine

Jan 1, 1990

By C. P. Patel

"The Sturgeon Lake Joint Venture volcanic massive sulpide deposit was discovered in 1970. Milling was started by Falconbridge Copper Ltd. at Sturgeon Lake in September 1974. The Sturgeon Lake pit and mill are located 88 kilometers by road northeast of Ignace, Ontario. IgnE1ce is a town of some 2800 people located on the Trans-Canada Highway, 241 kilometers west-northwest of Thunder Bay. The mill is treating an average of 1100 TPD producing separate concentrates of copper, lead and zinc. Initially, difficulties were experienced in achieving accept-able concentrate grades and recoveries but these were eventually overcome. This presentation describes current metallurgical strategy as practiced at the Sturgeon Lake mill.But first, a few words about the type of ore being treated. In geological terms the ore is classified into two main categories. They are the massive sulphides with underlying zones of stringer sulphides as illustrated in Fig. 1. The plan view is shown in Fig. 2. The areas of East-limb and North-limb are as shown. These last two ores have suffered enough alteration to cause problems during treatment. The massive sulphides consist of chalcopyrite, sphalerite, galena, tetrahedrite and small amounts of pyrrhotite among other gangue materials. The stringer ore is comprised of predominantly chalcopyrite intrusions into rhyolite and has lesser amounts of sphalerite and tetrahedrite. At present we are treating a predetermined blend of massive and stringer ores from zones that have been metallurgically tested to ensure compatibility with current treatment procedure in the plant. Ore responding to this treatment is classified as normal ore while the ore proving incompatible is classified as north-limb ore or east-limb ore."

Jan 1, 1980

Although bismuth mineralization is spread widely through the Lachlan Fold Belt in New South Wales, broad grouping of the various deposits can be effected on the basis of geographical and geological (age and type of associated rocks) affinities. As a result, significant concentrations of bismuth can be recognized in the Mid-Western granites, Cobar-type ore, the Yass Silurian acid volcanic belt, and the Albury, Bega, Braidwoodand Bathurst districts.In these deposits bismuth generally occurs in minor amounts associated with molybdenite, wolframite, scheelite, cassiterite, chalcopyrite, galena, magnetite, pyrite, arsenopyrite, and native gold. From this group of minerals three broadly defined associations can be recognized.I. Bi-Sn-W-Mo2. Bi-Au( -Te)3. Bi-Pb-Cu(-Au)There may be some interchangeability of these metals, as instanced by occasional Bi-Cu-W-Mo mirleralization, but pyrite and/ or arsenopyrite are usually prominent in all associations.The first two of these associations occur mainly in the form of narrow quartz veins rarely averaging more than O· 3 per cent Bi, although there is often a marked enrichment in ferruginous material in the oxidized zone.Most of these veins occur within or adjacent to granitic rocks of varying ages (principally Silurian or Devonian), although Bi-Au mineralization tends to be related to more basic igneous activity than the Bi-Sn-W-Mo association.The latter is also occasionally developed in pipes, usually coarse-grained and richer in bismuth (as at Whipstick, the principal mine in New South Wales with a production of 343 tonnes of the metal), or in lower grade, but probably larger tonnage skarn deposits. The bismuth-base metal association occurs mainly in Silurian acid volcanic sequences and may also form low grade but large tonnage deposits, such as is possibly developed at Cobar.

Jan 1, 1973

By Víctor Barúa R.

"La base de toda industria minera es el factor económico ya que se supedita a los costos de producción y la demanda en los mercados mundiales. Sin embargo, cuando el costo de producción sobrepasa el precio de la competencia del mercado, las utilidades disminuyen. En este sentido, el objetivo del texto señala la estabilidad económica de la industria como único medio posible para mejorar la producción a través la investigación, tecnificación y mecanización de métodos de trabajo en la minería de cielo abierto. La investigación permite que se reduzca los costos de producción que va desde el minado hasta la aplicación y uso de los metales por las industrias manufactureras. Asimismo el objetivo principal de la investigación es buscar nuevos métodos que mejoren la eficiencia de los equipos y mayor rendimiento en el trabajo. Finalmente, se hace una breve revisión histórica de la minería metálica donde se señala la función de la investigación y la técnica empleada en la mina a cielo abierto como parte del progreso de la industria. "

Aug 20, 1963

By E. Vega Hijar

La gestión de la información geológica como herramienta importante en la exploración minera, se refiere básicamente a la adquisición, generación, procesamiento, interpretación y almacenamiento de la información adquirida (base de datos, mapas, secciones, informes, reportes, otros.) al iniciar un proyecto y la información generada durante todo su proceso de desarrollo, lo que nos permitirá tomar decisiones idóneas sobre la viabilidad de nuestros proyectos.

May 1, 2008

By T. Egleston

The materials containing copper which are refined in the United Statrs, are, for the most part, the natiye noppers of Lake Superior. IJntil quite recently but little pig copper Was made for sale, and that came principally from the pure sulphorous ores of New England and the Sonth, and was generally sdd to reSneries not far from the ore filrnaceu. A stnall aiuoiint found its way into the'niarket which was produced either as the by-product of the treatment of gold and silver ores, or as the result of the treatment of impure copper ores; but both these grades, on account of the impurities they contained, were loolced on with stlspicion, and were not sought for. A11 the grtlGis of pig coppcr are sold by the unit of oopper contents, a great redtiction being made in the price when impurities are present. There are at the present time only three works which treat native copper, the two of the Detroit and Lake Superior copper Company, and the works of C:G. Hussey & Co., in Pittsburgh. There are a few works ivhich smelt sulphuroris ores and refine their pig; bo sides these t1le1-e arc a few siuall works where gig copper is refined uuly. Some of these purcIlase blscir copper, refine scrap, or simply refine such grades of ingot copper as are found in the market, but nlostly that from Lake Superior, for the purpose of getting it into swh shapes that can be handled cpmtriercially to advantage, such as in making large plates or high grades of wire fir electrical purposes. A nomher of such works are situated in the Xaugaturk Vatley aud elsewhcre in New England. The recent discoveryof vnlt~sblc ores in Ariarona makm it probable that within a few year8 the refining of capper In the United States will make great develupments. Up to the time of the discovery of the mines on Lake Superior, only a very small quantity of native copper had ever been foond, not sufficient to justify the erection of worlrs fbr its special treatment. It had, besides, never been found in very large maweq so that the discovery of greabblocks of it presented serious difficulties, not oolp in mining it,-I- but in bringing it into a merchantable condit'ion. It seemed a very simple process to melt these large maws,

Jan 1, 1881

By Juan Antonio Huamán Fernández

De acuerdo al estudio que realizó la Dirección General de Minería del Ministerio de Energía y Minas en el Perú, las estadísticas de accidentes fatales reportadas a escala nacional en el 2002 indican que la mayoría de accidentes fatales ocurridos en mina subterránea corresponden al 40% de desprendimientos de roca. Por lo cual, las empresas mineras preveen un programa basado en el desarrollo de la técnica de Gestión de Riesgos, que les permita un control en la seguridad del proceso. En este sentido, el presente texto desarrolla una técnica que identifica los diferentes factores que intervienen en los riesgos principales a través de los riesgos asociados; es decir, cuáles son esos riesgos asociados que influyen negativamente en cada una de las tareas que puedan causar accidentes.

Jul 31, 2003

By M. D. Cooper

IN spite of the uncertainty in the bituminous coal industry during 1933, progress worth recording has been made. Along with other industries, coal has felt the effects of business stagnation, but even in the worst weeks of the past four years, .the total production of bituminous coal in the United States was seldom less than half the production in some of the best weeks of the more prosperous years, a record better than that of many industries. However, the competition of other fuels and sources of power, together with the increased efficiency in the use of coal, has brought anxiety to producers. This has resulted in pressure for reduction of costs, not always by the wisest means. On the other hand, the effort to survive has directed increasing interest toward research, a wholesome development in a difficult situation. Wages, limitation of hours of labor, and the NRA have occupied much time and thought. Following a period .of wage cutting paralleling price cutting, the industry found itself rather suddenly faced by the President's Agreement, followed in due course by the Code, and then in many places by the agreement with the United Mine Workers. Although there is still some uncertainty in regard to the detailed working out of the new arrangements, there seems to be an honest endeavor by the signatories to the Code and Agreement to work them out in a straightforward manner.

Jan 1, 1934

By T. Holmes, J. Middlemiss

"Agnico-Eagle (AE) has been operating their Kittila Mine in Northern Finland since 2008. The mine has experienced considerable ore flow problems with ratholing, bridging and freezing in their mill feed bin since start up. In the first winter of operation, the entire central portion of the contents of the cylindrical flat-bottomed 2000 tonne mill feed bin froze. Flow was erratic and could only be achieved through small diameter ratholes. To maintain a reasonable, albeit limited, feed to the mill, the bin had to be kept less than ½ full and a portable steam generator was brought in to melt the frozen agglomerates that frequently blocked the outlets. The combination of limited surge capacity and frequent outages required the crushing plant to operate 24/7 and resulted in inconsistent production levels and high operating costs.AE had planned to expand the processing plant to increase throughput by about 30% when they transitioned from open pit to underground ore. These plans presented an opportunity to improve the material handling.To avoid the problems experienced with the original mill feed bin, AE enlisted Jenike & Johanson Ltd. (J&J) to test samples of the ore, and based on the measured flow properties to provide design recommendations to ensure that the new mill feed bin would operate reliably. The new 2000 tonne expanded flow mill feed bin and apron feeder were installed in 2014 and are now supplying almost 93% of the total mill feed with the remaining coming from the original bin.IntroductionIn early 2009, AE engaged J&J to visit their then recently opened Kittila mine and mill in Northern Finland (Figure 1). Over the first half-year of operation, production had been restricted in the ore handling and storage system by flow problems such as ratholing, bridging and freezing including blockages of chutes and hoppers as a result of frozen fines buildup and large frozen agglomerates. AE wanted to increase production in the existing open pit mine and mill feed operation and also wanted to avoid similar ore handling problems when they commissioned the new underground mining system under development at that time."

Jan 1, 2017

This appendix contains the list of equipment, their corresponding number and their specifications with the quotations from the vendors/ manufacturers who can supply this equipment. The listings are arranged by process plant areas.

Jan 1, 1979

By Edwin Deveaux

Durante el período de descanso 2008 - 2010, la mina Falcondo se preparó para implementar una metodología de minaje hacia pilas intermedias, denominado "Patio Piles", en sustitución del minaje original directo a la Planta de Procesos. El proceso se evaluó durante tres años y y luego de superar algunos retos como del costo, doble manejo y el control de humedad, se implementó exitosamente en el rearranque de operaciones a inicios del 2011. En este sentido, el presente texto señala la introducción de la calidad de pilas intermedias, así como la metología de extracción/ reforestación progresiva para aumentar las áreas abiertas que ya han sido reforestadas.

Oct 21, 2015

By H. Reimer

The rates of return on investment are examined for several major Canadian mining companies. Because we are dealing with a highly cyclical industry, subjected to widely fluctuating metal prices, rates of return are examined over a 20-year period. Conveniently, the first decade examined reflects the period when the industry enjoyed incentives to develop deposits; during the second decade, incentives were reduced and the industry became the most heavily taxed industry in Canada. The high rates of inflation since 1973 have distorted the real rates of return on investment if one considers replacement cost.

Jan 1, 1977

By F. S. Crawford

"After many years of safety activity in the United States in one form or another it becomes increasingly evident to those in contact with safety work that to achieve continuous good results in accident prevention there must be an aggressive organization behind the safety movement at each mine with fairly definite plan and policy. A study of the methods used by various companies and the results they have attained will be of value to the common cause of safety promotion.A study has been made of the safety records of the Menominee iron range in the Lake Superior district, and of data from the county mine inspector's report. Several companies on this iron range that have attained a certain measure of success in their work of accident prevention have given data, and a summary of their safety methods is presented.The Menominee iron range of Michigan lies in the southern portion of the upper peninsula of Michigan, bordering on Wisconsin. It consists of two main. divisions--the West Menominee Range, situated in Iron County in the vicinity of Iron River and Crystal Palls, and the East Menominee range situated in Dickinson County in the neighborhood or iron Mountain, Mich. The mines about Iron River and Crystal Falls are peculiarly subject to fires in a carbonaceous, sulphur-bearing black slate which appears in the footwall. This gives considerable trouble because fires in this material start from spontaneous heating. The methods of mining are top slicing and open stoping, working on benches along the sides of the stopes. The character of the ground varies from medium Soft ore to relatively hard ore which permits open stoping. Approximately one-third of the operating mines are equipped with a fan for main mechanical ventilation. The remainder are ventilated by natural draft. The East Menominee range is the older, top slicing having been used there for a number of years, and the timber mats have boon well developed. In common with all districts, some companies pay more attention to safety than others, although, those which do riot have the best records do pay some attention to safety.During the past three years the annual production per man employed has remained about constant, but in many mines a general decrease is shown in the accident record. The variation in the results attained can be ascribed mainly to the earnestness with which accident-prevention work is pursued, essentially regardless of the method of mining used. This is shown to be generally true, because the record indicates a steady decrease in one mine with an active safety department, while in adjoining mines with the same kind of ground and method of mining but where not such intensive attention has been paid to safety work, the accident record is high."

Oct 1, 1931

By N. Andersen

During the preliminary design phases and feasibility study of a proposed vertical shaft, a vertical diamond drill-hole is normally drilled on the site. This paper outlines how rock mass characteristics, in-situ rock stress, rock strength, hydrological characteristics, and structural parameters can be determined using wireline logging of this borehole. In addition, a rock mass classification scheme is developed, based on published work, and in particular the Q-factor is adapted to assess the stability of raise-bored shafts. The ‘stick plot’ is introduced, which combines all geotechnical parameters applicable to the stability of a vertical shaft into a colourcoded format where cross-correlations can readily be made on a day-today basis during the shaft-sinking process.

Jan 1, 2015

By George J. Young

DR . JOHN A . CHURCH, in his treatise on the Comstock Locle 1 gave a full and clear account of the conditions of the mine during the period of greatest activity. The difficulties in the way of deep mining at that time were excessive water and high temperature. The drainage of the mines taxed the financial resources of the mining companies, and the high temperatures restricted the capacity of the miners for underground labor. In spite of these difficulties exploratory work was continued until the financial burden of removing the water became too great. The companies then restricted the work to the upper levels. The years 1883 to 1886 marked the period of cessation of deep mining. For 12 years thereafter mining was confined to the levels above the Sutro tunnel; and, while the question of drainage was more or less agitated, nothing of importance was done until the formation of the Comstock Pumping Association in 1898. Since that time successive levels have been drained until, at present, on the north-end mines, a depth of 700 ft. below the Sutro-tunnel level has been reached. Mining is now carried on in the Ophir mine from the 1,700- to the 2,200-ft. levels, and a winze is being sunk to make connection with the 2,300-ft. level (the 2,450 ft. of the C. & C. shaft). In 1903-the Ward Shaft Association was formed to undertake the draining of the Central and Gold Hill group of mines, and at the present time a depth of 2,500 ft. has been reached in the Ward shaft. The situation at the Ward looks promis¬ing, and the 3,000-ft. level may be reached in the near future. It is proposed to establish a large pumping-station on this level, and then begin the opening of known ore-bodies and the prospecting for new ones. The main factors which have contributed to the successful solution of the drainage problem are the Sutro tunnel, the use of the hydraulic elevator as a sinking-pump, the concentration of pumping-units, and cheap electrical power. The question of high temperature and its control still remains as a minor but important problem. The temperatures encountered in the new workings are as great as those in the earlier periods. The Comstock was considered the hottest group of mines in the world, and I am not aware of similar conditions in any other mining-district. A water-temperature as high as 160° F. has been reported from the Ward shaft, and temperatures below the Sutro tunnel are very high in many instances.

Nov 1, 1909