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By N. Kuyucak

While Acid Rock Drainage (ARD) occurs naturally, its management poses challenges especially at the decommissioned sites. Two passive systems were designed and implemented at two different decommissioned mining sites in Canada in order to treat the seepage with ARD characteristics. One seep originating from a reclaimed tailings pond was neutral mine drainage (NMD) containing circumneutral pH and dissolved metals (e.g., nickel, zinc) in elevated concentrations. The other ARD from a tailings stack showed net acid drainage characteristics with low pH and higher metal concentrations than regulated limits. Due to the different ARD characteristics occurring at each site, different types of treatment systems were designed and implemented. Both sites experience extreme winter conditions. The NMD has been treated mainly by limestone drain and aerobic systems since 1997. The acid ARD has been treated by a system consisting of an anaerobic sulfate reducing bacteria (SRB) cell, an aerobic cell and a limestone filter since 2004. As this site has no access roads, space, or power, a significant capital cost as well as sludge disposal/storage requirements would have been required to institute a chemical (active) treatment system. Both systems have been successfully treating seepage and producing a water quality year round that could comply with regulated objectives.

Jan 1, 2010

By M. Boucraut

The authors investigate the influence of the basicity index CaO / Si02 on the sintering properties of hematite ore mixtures. The experimentation was performed with three different mixtures of ores from Tazadit, Nimba, Mano-River, Itabira, Marcona, Goa, Mapawa and Cassinga. Increasing the basicity index CaO / Si02 between 0.1 and 3, chiefly through limestone admixture makes possible to reduce the thermal consumption of sintering and to improve the physical and chemical properties of the sinter. In the case of a plant using hematite ores, it seems interesting to produce an hyperbasic sinter and to complete the blast furnace burden with calibrated ore or acid pellets.

Jan 1, 1968

The paper describes a practical methodology based on numerical modelling for the prediction of progressive failure of underground mine stopes with cable bolt support. A case study of the 40-761 stope at Kidd Creek Mine, Timmins, Ontario is presented. The stope was mined by blasthole open stoping in 1986 as a lead stope within a mining block between 36-1 and 38-2 levels. Initially designed to peak at 38-2 level, the stope back caved upwards approximately 40m towards 36-1 level. Cable bolts were installed above the stope from 36-1 level after caving had begun. The stope eventually stopped to cave when the falling rock mass encountered a sufficiently high cable density. The paper provides details of the geomechanical data and modelling results of the case study. Numerical modelling is carried out using a finite element package known as e-z tools which has, among other things, a special cable/rockbolt simulation capability.

Jan 1, 1994

By David G. Van Hersett

The single most unique design feature of the Centralia Coal Mine is the public information program. Just what the heck does public information have to do with the development of a coal mine? The utilities of today have had to build larger and larger plants to keep down the costs of power to the consumer. The large plants require huge amounts of capital, take up large areas of real estate, consume unprecedented amounts of coal, and generate large quantities of waste products which have to be reckoned with. Coal mines supplying these plants have also increased in size and production to meet the power plants' unending appetite for coal. This means the disturbance of great areas of land and significant alterations to the landscape. Today's public is greatly concerned about the environment in which he is living. The great size of a power plant with its large stacks, coal piles, and the coal mine with its large earth movers, disturbed acreages and the resulting waste products of both operations appears to present a threat to his environment. Because of this,' many power plants and coal mines are having public acceptance problems. This has resulted in the passage of stringent legislation and in some cases brought upon construction delays for major power plants.

Jan 1, 1970

By C. L. Schneider

The calculation of the liberation spectrum in the product from continuous milling operations is a problem of considerable importance and is difficult to solve because the population balance equation must be integrated in two-dimensional space. Complete solutions require the estimation of a large number of parameters unless a structural model of the ore texture can be used. A very simplified textural model based on the use of the modified Andrews-Mika diagram and the PARGEN simulation of multi-phase particles has been formulated and is used to simulate the behavior of a continuously operating laboratory ball mill. A sensitivity analysis for this mill has been done to show the likely effect of model approximations on the predicted liberation spectrum which will be measured.

Jan 1, 1992

By Kerry Spickelmier

With the dissolution of the former USSR and a welcoming of foreign, minerals expertise by a host of developing countries, a "new," more international, world of minerals is open to the mining industry. However, even in the new frontier, the old laws of nature still apply. For those attendees of the 98th annual Northwest Mining convention, the adage "survival of the fittest" commanded particular attention. Miners, engineers, geologists and other unique species traveled to Spokane in December to learn of adaptations they can make to assure, or at least prolong, their place in the mineral industry's land of the living. You have heard the tales of the spotted owl and the desert tortoise, but add to this endangered list the North American mining industry. During a session on international investment criteria, D. Silver of Balfour Holdings (Littleton, CO) blamed excessive environmental regulation, 1872 Mining Law revision and the anti-mining-and-business attitude of our government for migrations from and extinctions within the domestic mining population. "We've been on a death curve for some time," Silver said, "with a lower birth rate and a higher death rate. In the last four years, we've lost 60% of the gold producers in North America, and we're down to 110 companies. The entire industry has lost about 400 companies and is now down to 2800." Unreasonable regulation founded on emotion rather than scientific fact has been the chief cause of death, according to many of the convention speakers. B.J. Kennedy, president and chief operating officer of FMC Gold (Reno, NV), emphasized, "We have accepted a regulatory environment - but we oppose being strangled to death by unreasonable regulations."

Jan 1, 1993

By M. S. Klima

A 25-mm diameter dense-medium cyclone was tested to investigate the effects of geometry and operating conditions on cyclone performance when processing -150 I'm coal. The emphasis was on examining those variables (e.g., flow rate and inlet velocity) which impact the separation kinetics (specifically the number of g's and the mean retention time) and the occurrence of apparent bypass. Apparent bypass, indicated by partition curve "tails", results from the short circuiting of the feed coal to one or both of the product streams and represents a loss and/or contamination of the clean coal. This paper presents the results for this series of tests.

Jan 1, 1993

By D. Spitty

There are enormous complexities with mine planning and the problem itself presents a huge challenge to the existing mine planners performing this activity. Mine planning optimization supports planners to determine ?What are the best increment excavation sequence and the best material blending combination such that throughput, quality, cost, utilization and Net Present Value (NPV) targets are met?? It is achieved through using an advanced scientific approach that has been specifically adapted to address the mine planning dilemma.

Feb 23, 2014

By David A. Fawcett

An auxiliary cross-pit mining system, working in tandem with the prime excavator, is evaluated technically, operationally and economically for application in the selective removal and replacement of soils and unconsolidated ovezburden. Previous studies on cross-pit technology and applications of this technology are briefly reviewed. Stratigraphy plus pit, operating and economic parameters are assumed and applied in the evaluation and comparison of a base case dragline system with two alternatives - a dragline/scraper-dozer combination and a drag- line/cross-pit system combination. The economics of the proposed cross-pit system favour it as a viable alternative to conventional systems.

Jan 1, 1981

By M. Z. Mubarok, Z. T. Ichlas, A. T. Sugiarto, K. Sukamto

The use of ozone as an oxidant for the direct leaching of zinc sulfide (sphalerite) concentrate in sulfuric acid medium under atmospheric pressure was explored. The influence of acid concentration, feed gas injection rate, particle size distribution, stirring speed, temperature and slurry density on zinc extraction efficiency was examined. The experimental results showed that the leaching efficiency depends on all of these operating parameters except for stirring speed. It was found that essentially complete dissolution of zinc from the concentrate with the present method can be achieved in only about seven hours under the conditions of sulfuric acid concentration of 2 mol/L, particle size smaller than 74 µm, slurry density of 50 g/L, stirring speed of 420 rpm and feed gas injection rate of 1 L/min at ambient temperature. The experimental results suggest that the dissolution reactions produce independent elemental sulfur that is readily floated and can be easily separated rather than forming a layer on the surface of the reacted particle, as usually observed in a system with ferric-sulfate as oxidizing agent. It was therefore determined that the dissolved ozone play a key role in improving the rate of zinc dissolution from the concentrate. Analysis of the leaching kinetics indicate that the leaching rate follows the shrinking particle model, and the overall dissolution rate of zinc is controlled by a surface reaction.

By CORNELIUS STEPHANUS LODEWYK SCHUTTE, WIEHAN ADRIAAN PELSER, JEAN HERMAN VAN LAAR, MICHAEL DAVID HARMSE

Rising electricity costs in South Africa have resulted in a need for optimized compressed-air networks in the mining environment. As a result, the financial benefit of air receivers needs to be reconsidered along with the economic dispatch strategy. This study investigates the use of an evolutionary algorithm in the mining industry to determine the potential financial benefit for various-sized air receivers, as well as their dispatch strategy. A genetic algorithm was selected due to the improved solution reliability and accuracy compared to other optimization techniques. This study indicates that a genetic algorithm can be used to determine the optimal dispatch of compressed air in the deep-level mining industry. Further, this study indicates that air receivers are financially viable in the mining industry and can be used to reduce operating costs, improving profitability.

Dec 1, 2022

By S. P. Singh

Drifts are the nerve centre of underground mining. They provide essential communications between primary openings and production areas. In view of their strategic importance in the overall safety, economy and productivity of mines, an empirical approach for blast design during drifting has been proposed in this paper. The approach was developed with the objective of minimum blast damage and provides computerized blasthole patterns for drifting operations. The drift blasting practices and problems in Canadian mines have also been reviewed in this paper.

Jan 1, 1991

By John V. Beall

The Mining Engineering Handbook is written primarily for persons interested in the economic extraction of minerals. Not everyone referring to this book will be knowledgeable about mining and, therefore, this section is intended to explain to interested persons the scope of mining as well as fulfilling the title of "Mining's Place and Contribution" among the industries of society. 1.1-MINERALS, ROCKS AND ORE In the year 1971, the number of known elements amounted to 104. Fifteen of these have been made only in the laboratory, others may have persisted from the primitive atmosphere, but, by and large, elements originated from magmas or igneous rocks of the outer rocky shell of the earth. Only eight elements constitute 98% by weight of the earth's crust. These are oxygen, 47%; silicon. 28%; aluminum, 8%; iron, 5%; and sodium, magnesium, potassium and calcium, less than 4% each. These common elements and the other less common ones are the building blocks of minerals, of which there are over 2,000 varieties. According to Webster: "A mineral is an inorganic substance occul.ring natura!ly in the earth and having a consistent and distinctive set of physical properties and a composition that can be expressed by a chemical formula. The term is sometimes applied to organic substances, such as coal." Thus, minerals are precise combinations of elements. Rocks, as distinct from minerals, are composed of assemblages of minerals. When minerals are found in sufficient concentration to warrant extraction by mining, the mineralized area is considered an ore deposit. The definition of ore is mineral that can be extracted from the ground at a profit. The economic connotation is implicit in the word ore. Since most of the useful elements compose such a small percentage of the earth's crust, the occurrence of ore deposits as we know them would not have transpired had not geologic processes concentrated the elements (see Sec. 4). 1.2-DEFINITIONS OF MINING TERMS Extensive coverage of the many descriptive terms used in mining may be found in a good mining glossary, such as is available from the Superintendent of Documents (see Sec. 35), but for convenience a number of the more common definitions are given here. Mining may be defined, as by A. B. Cummins, as the act, process or work of extracting minerals or coal from their natural environment and transporting them to the point of processing or use. Mining techniques are applied to extracting metallic minerals, such as ores of gold, copper, lead or zinc; to fuels, such as coal, anthracite, lignite and tar sands; and to nonmetallic minerals, such as lime-

Jan 1, 1973

By Randall E. Brown

Irrigation simulates a climate change so that crops can be grown that otherwise would not thrive. The abundant sunshine and warm weather of many arid regions induces a rate of growth in excess of that in cooler, moister regions. Hence, the arid part of eastern Washington, traversed by the Columbia River, is admirably suited to irrigation. The Pasco Basin lies in south-central Washington at the south end of the Columbia Basin Irrigation Project of the U.S. Bureau of Reclamation. The Basin, because it lies in the rain shadow of the Cascade Mountains, receives only 6 to 10 inches of precipitation a year with somewhat greater amounts, commonly as snow, on the higher hills. Recent extremes included 3 inches of precipitation from August 1967 to August 1968, and 12 inches in the succeeding "12 months. Most of the precipitation falls during winter. If it were to fall in summer or were evenly distributed throughout the year, evaporation rates probably would produce a true desert.

Jan 1, 1971

By H. C. Harrell

The Tennessee Valley Authority began employing geophysical well logging for foundation investigations in October 1973. Since that time more than 3,000 holes have been evaluated for engineering purposes. The Tennessee Valley Authority has not actively used geo-physical well logging for exploration of construction materials, but we feel that much of the information derived from geophysical logs for foundation exploration is applicable to the construction materials industry. This paper will then discuss geophysical logging as applied to foundation engineering and, by implication, the feasibility of use in construction materials exploration. The use of geophysical logging and percussion drilling instead of coring has greatly expanded TVA's data acquisition capabilities and has also resulted in substantial savings in time and money. Economical boreholes are obtained through the use of large percussion track drills (Figure 1). This equipment is capable of drilling through the overburden, setting steel casing on the top of rock, and drilling the rock beneath the casing. Holes as deep as 400 feet (121.9 m) have been drilled by this method.

Jan 1, 1977

By A. S. Ibrado, D. W. Fuerstenau

"Gold, silver and copper form various complexes with cyanide, of which only the singly charged dicyano form adsorbs appreciably on activated carbon. The adsorption of the dicyano complexes appears to be controlled predominantly by chemical reaction at the surface of a shrinking unreacted core. Metal uptake over time is non-linear, which eliminates control by boundary layer diffusion. The rate of adsorption is not enhanced by a reaction interruption, which suggests the absence of concentration gradients in the pores. Finally, the rate of adsorption increases with decreasing activated carbon size in a manner consistent with the shrinking core model. The results of this investigation accentuate the importance of efficient acid washing of carbon and removing carbon fines from the barren carbon stream. INTRODUCTION With the dwindling reserves of high-grade ores, most of the world’s gold is produced from low-grade ores by cyanide leaching. In the past, leaching was followed by the Merrill-Crowe process, in which gold is precipitated from clarified pregnant solutions by zinc cementation. This process is still being used for high-silver ores, where the cost of carbon stripping becomes prohibitive. For deposits with silver-to-gold ratios of about 4 or less, adsorption on activated carbon would be the usual solution purification step taken. The process simplifies solid-liquid separation and offers a viable solution to preg-robbing organic carbon in some ores. The modern industrial application of carbon adsorption started with the carbon-in-pulp (CIP) process, where carbon adsorption was used mainly as a solution purification step. In 1973, Homestake Mining Company commissioned the first large-scale CIP plant in the U.S.A.1 Later, carbon was added earlier in the circuit to control preg-robbing by adsorbing gold cyanide onto activated carbon as soon as it is dissolved. The scheme is successful because activated carbon is a stronger adsorber than the organic carbon found in preg-robbing ores. This process came to be known as the carbon-in-leach (CIL) process. Numerous research investigations have been performed on the chemistry involved in the CIP process, which at the time of its introduction was not clearly understood. Of these, research on the kinetics of adsorption probably bears the most immediate impact on industrial practice,2,3 where adsorption systems rarely reach equilibrium, if at all, and slight slowdowns in the adsorption rate can translate into significant decreases in revenue. To illustrate this, organic compounds, like flotation reagents, have been known to impair CIP circuits. However, laboratory tests showed that the organic compounds do not significantly affect the adsorption capacity of activated carbon. Rather, the harmful effect may be attributed to a lowered adsorption rate.4,5 Also well known is the faster rate at which fine activated carbon powders reach equilibrium compared to coarse activated carbon, even though the final (equilibrium) amount of material adsorbed per unit weight is the same."

Jan 1, 2015

By HONGWEI YANG, Lili Zhang

Copper slag is mainly used in cutting tools, abrasives, asphalt pavement, road construction, and in the production of concrete as an alternative to sand and cement [1]. As a renewable resource, only about 15-20 percent of the slag is used for these applications, and the dumping or disposal of surplus unused slag results in waste of a certain amount of usable metal in the feedstock [2]. In this work, the oxidation behavior of copper smelting slag under nonisothermal condition is studied using data obtained by the thermogravimetric (TG) method, and the kinetics parameters and reaction mechanism of oxidation are determined. It provides a theoretical basis for the comprehensive recovery of iron resources in slag and the selection of reasonable slag-making conditions.

Oct 1, 2022

By Barbara J. Arnold

Combat Infantrymen’s Badge and Bronze Star Medal. Following his discharge from the Army, he re-entered SDSM&T in 1946 and earned a B.S. degree in Metallurgical Engineering in 1948. He then received an M.S. from Montana Tech (MT), worked several years in industry and then as an Assistant Professor at the University of Washington (Seattle). He joined his Montana Tech colleague, Douglas W. Fuerstenau, at The Massachusetts Institute of Technology (MIT), receiving his doctorate in 1957. While at MIT, he married Clare M. Donaghue of Dorchester, Massachusetts, in 1955

Jan 3, 2022

By A. Röttger, W. Theisen, J. Küpferle, M. Alber

"Wear of TBM tools significantly affects tunneling advance rates. Wear-prediction models are based (amongst others) on the abrasivity of the present geology, which is determined via laboratory tests. To evaluate the results from such tests in context, this work considers the tribological system TBM tool from a materials technology perspective. In so doing, the microstructures of different application-oriented materials are presented and discussed in terms of their wear behavior and wear resistance. The significant influence of tool materials on the abrasivity of the geology and thus wear prediction models has already be identified. LCPC, Cerchar and nano-scratch experiments have been performed as confirmation. Material-dependent wear mechanisms and their correlation in terms of tunneling have shown that it is mandatory to consider the complete tribological system to estimate the wear of TBM tools. 1 INTRODUCTION Mechanized tunneling is vital to ensure necessary infrastructure development in megacities like Tokyo (Bay Tunnel), Istanbul (Eurasia Tunnel) and Mexico City (Tunnel Emisor Oriente). The use of Tunnel Boring Machines (TBMs) has been established for many years. In contrast to other methods such as boring and blasting or excavation using dredgers, tunneling with TBMs allows simultaneous excavation and removal of both the mineral and tunnel lining by tubbing segments or shotcrete. This makes tunneling more efficient, allowing for faster development of the tunnel in both hard rock and soil [1]. When budgeting such tunneling projects, precise planning and coordination in terms of tunneling technique choice (e.g. EPB or Slurry-shield), the relevant geology, and the associated penetration rates and tool wear are required. In particular, wear to TBM tools has a significant impact on tunneling progress. Due to wear, tools become dulled or lose their functionality because of brittle material behavior, thus reducing penetration rates and therefore tunneling efficiency [1]. As a result, additional tool changes are necessary, leading to higher overall costs due to down times and maintenance costs. Therefore, there is strong interest in a reliable and precise wear prediction model for TBMs. As already mentioned, the geology and associated wear of the tunneling tools define the maintenance times."

Jan 1, 2016

By M. B. Mirza, W. A. Sadik, B. T. Stanley

This paper presents the ventilation design for an underground testing facility in a salt medium. The under-ground workings consist of two 3.6 m-diam (12 ft-diam) watertight shafts and about 1830 m (6000 ft) of drifting. These facilities are designed to provide access for an in situ testing of a salt horizon in which a variety of hazardous and nonhazardous materials could be temporarily stored or permanently deposited. The ventilation system includes a design basis for gassy mine conditions and provides for the option of bulk air cooling and heating.

Jan 1, 1987