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By S. Jennings

The Red Dog massive sulfide deposit is located in the western Brooks Range of Alaska 100 miles north of the village of Kotzebue. It contains the largest zinc reserve in the world. Reserves were doubled in 1995 with the discovery of the Aqqaluk deposit and significantly increased in 1996, with the discovery of a deep zone of mineralization to the north. At present the global reserve and resource is 143 million tonnes of 16.1 % zinc and 4.3% lead. Red Dog is a silica + sulfide synsedimentary replacement deposit hosted in barite and black shale of the Mississippian Kuna Formation. Red Dog was thrust northward during the late Mesozoic Brookian orogeny. Understanding the setting of the deposit at the time of formation and its subsequent deformation history is critical to current exploration efforts and to future discoveries in the district.

Jan 1, 1998

By G. J. Allen

Kennecott Copper Corporation's Nevada Mines Division initiated a program to stabilize the inactive portions of the tailings disposal area and perimeter dikes in 1946. To date, approximately 1,000 acres have been stabilized with vegetation and ground cover.

Jan 1, 1978

An atomic force microscopy (AFM) has been applied to study the adsorption of collectors on mineral surfaces in a copper/molybdenum flotation system. AFM images show that collectors absorb on chalcopyrite surface in patches at pH 11. A study of temperature effect on surface morphology excludes the possibility that these patches are nanobubbles forming on hydrophobized mineral surface. Hydrocarbon oil absorbs on molybdenite quickly, while KEX (potassium ethyl xanthate) has little affinity for molybdenite. Pyrite is much more reactive in water and its surface is easily coated in Ca(OH)2 solutions at pH 11. Based on the obtained AFM images, the adsorption of chemicals on mineral surface and its impact on copper/molybdenum flotation were discussed.

Jan 1, 2012

By F. Chase, D. Pappas

Pillar recovery has been associated with nearly one third of roof fall fatalities in underground coal mines during the past decade. Safe pillar recovery requires global stability and local stability. Global stability is addressed primarily through pillar design. The local stability risk factors include cut sequence, the final pillar stump, supplemental supports (timbers vs. Mobile Roof Supports (MRS)), roof bolting, and many others. The National Institute for Occupational Safety and Health (NIOSH) has evaluated each of these factors through field research and analysis of accident statistics. The paper discusses design methods and technologies that have been transferred to the mining community and implemented.

Jan 1, 2003

By P. F. Ziemkiewicz

This project evaluated the performance of nine passive treatment methods by studying 137 treatment units in eight eastern states. Performance was normalized according to construction cost, projected service life and tons of acid load treated. Results were dimensioned as $/tons of acid load treated/year. These costs were then compared to those of chemical treatment. Sites that achieved acid load reductions at costs below those of chemical treatment were considered successful. In addition to evaluating the performance of the treatment methods, this paper describes the various passive treatment systems, their applications and performance data for individual treatment units.

Jan 1, 2003

By Martin Wehrli, Oliver Schneider

"MOTIVATION Tunnel construction companies must keep costs low, finish projects in less time and still meet the high quality and safety standards. Therefore, their main goal is always to optimize the tunnel excavation process. Traditional geodetical methods are used since more than 100 years to ensure an exact breakthrough of a tunnel. Evolving sensors, sensor fusion and increasing computation resources opened new fields of application for geodetic solutions in tunneling. These solutions offer new ways to reduce costs and risks in tunneling. INTRODUCTION Nowadays in tunneling, geodetical measurement methods are not only used for guidance, but also for various other applications. This paper gives an overview about where geodetical measurements are used today and highlights their benefits for safety and costs aspects. Furthermore, advanced solutions are introduced. In progressive projects, they have already become state of the art technology and are in use daily. STANDARD GEODETICAL MEASUREMENT APPLICATIONS In drill & blast tunnel construction processes, there are many standard geodetical applications used in the different construction phases, each having different requirements regarding accuracy. In the excavation construction stage, guidance tasks and setting-out of various positions is done by the foremen. Thanks to simplified measurement tools, the foremen are enabled to carry out these measurement tasks themselves without requiring deep surveying knowledge. In contrast, deformation analysis and network measurement campaigns need sophisticated planning and a profound education in surveying. Therefore, these tasks are carried out by surveyors. Profile control and as-built documentation is required in each construction phase. Depending on the requirements of the project, this task can be carried out either by the foremen or a specialized surveyor. Table 1 provides an overview over typical surveying tasks in an underground project including information about who is doing the job and the according accuracy requirements. The listed tasks are described in more detail below."

Jan 1, 2016

Fine coal is substantially more costly to process than coarse coal because of technical difficulties associated with separating fine particles and removing process water from both clean coal and refuse. Therefore, companies are often forced to discard coal fines to waste impoundments. According to a recent report published by National Research Council, the U.S. coal industry is discarding 70-90 million tons of coal fines annually to 713 active impoundments, most of which are located in Central Appalachia. On October 11, 2000, a 72-acre impoundment near Inez, Kentucky, accidentally released 250 million gallons of coal slurry into nearby underground mines, creeks, rivers, and schoolyards, thereby creating serious environ-mental concerns. Fortunately, recent advances in separation technologies make it possible to recover fine coal more efficiently from existing coal preparation plants and from waste streams previously discarded to impoundments. The availability of these new technologies allows companies to increase profitability and minimize environmental risks, which are conducive for achieving sustainable mining.

Jan 1, 2003

By Natasa Mitevska, Predrag Djordjevic, Zivan Zivkovic

This paper presents the results of an experimental investigation into the distribution of copper in the slag of an industrial reverberatory furnace sulfide concentrates smelting process in the copper smelter RTB Bor (Serbia). The influence of copper content in the matte, the temperature and the height of the slag on the content of copper in the slag was determined as Cuoxide, Cusulfide and Cutotal and was based on possible mechanisms for the loss of copper in a silicate slag from the smelting of sulfide copper concentrates. The greatest quantity of copper in the silicate slag was found in the form of matte particles, which were captured in the slag as a result of the “flotation” of SO2 gas which was formed by magnetite reduction with FeS at the slag–matte interphase boundary.

By Natasa Mitevska, Predrag Djordjevic, Zivan Zivkovic

This paper presents the results of an experimental investigation into the distribution of copper in the slag of an industrial reverberatory furnace sulfide concentrates smelting process in the copper smelter RTB Bor (Serbia). The influence of copper content in the matte, the temperature and the height of the slag on the content of copper in the slag was determined as Cuoxide, Cusulfide and Cutotal and was based on possible mechanisms for the loss of copper in a silicate slag from the smelting of sulfide copper concentrates. The greatest quantity of copper in the silicate slag was found in the form of matte particles, which were captured in the slag as a result of the “flotation” of SO2 gas which was formed by magnetite reduction with FeS at the slag–matte interphase boundary.

By Michael Jatczak, Brett Robinson

The South Bay Ocean Outfall tunnel is located at the U.S./Mexico Border and is one link in a system designed to treat and dispose of raw sewage entering the Tijuana River Valley from Mexico. The 11 finished diameter tunnel extends 19,000’west from the bottom of a 200 deep, 36 diameter drop shaft. At the western terminus of the tunnel, a Riser shaft connects the tunnel to conveyance and diffuser pipes on the seabed. The tunnel runs through the San Diego Formation, consisting of clay, silt, sand, gravels, cobbles, and boulders. A Mitsubishi Earth Pressure Balance (EPB) Tunnel Boring Machine equipped with a large variety of monitoring and control devices was used. This paper will provide an overview of the Project’s construction, with special emphasis on the value of the electronic data acquisition system.

Jan 1, 1999

By B. V. Driga

The paper presents the evaluation method of the thermal power potential of the salt lakes developed in collapsed salt mines in Romania. It is well-known that the hydro-chemical stratification of these lakes favors warmer internal layers. The degree of heat varies during the year, but, taking into account the large number of genetic lakes of this type, it can be used as a local utilizable power source. The authors analyze the correlations between the physico-chemical parameters of the water and the degree of heat stored as a function of the morphological parameters of the lakes, as well as the technical parameters for capitalizing on this power.

Jan 1, 2008

By Robert H. Carpenter

Downstream dispersion curves for certain trace metals were obtained from two mineralized areas in the southeastern U. S. In Lincoln Co., Georgia, 7 sample sets were collected downstream from the Magruder mine, a polymetallic sulfide deposit (Zn-Cu-Pb-Ag-Au) in metavolcanic rocks. Five sample sets were collected along Joe Mill Creek in Grainger Go., Tennessee, downstream from a zone of zinc mineralization in carbonate rocks (Mississippi Valley-type). In both areas, analyses were made of Fe-Mn oxide coatings on lithic fragments and quartz pebbles, and the -80 mesh fraction of the stream sediment. A comparison of the dispersion curves reveals the following: 1.) the anomaly/background ratio is markedly higher in the Fe-Mn oxide coatings for zinc and copper; 2.) the anomaly/background ratlo is markedly higher in the -80 mesh fraction for lead which is not concentrated in the coatings; and, 3.) the Zn/Mn and Cu/Mn ratios in the coatings are useful in that they enhance downstream derectability of mineralization as well as provide for a simpler analytical procedure. There are several potential advantages of using coatings vs. the conventional -80 mesh fraction in stream sediment surveys. Because soluble metal is brought into the stream mainly in groundwater, deeper anomaly sources may be detectable from the oxide coatings than from clastic fractions of alluvium where much of the metal is derived from erosion of soils. Variability due to sampling may also be reduced, providing better discrimination of anomalies. In areas of glacial or alluvial cover, coating surveys may be particularly applicable.

Jan 1, 1975

By Peter T. Luckie, Felicia F. Peng

INTRODUCTION The maximum recovery of cleaned coal at the required quality is of major concern to plant operators. However, the quantity and quality of products of coal cleaning, predicted by theoretical calculation based on washability studies and determined in the operation of actual commercial cleaning plants, will be different for each coal. Therefore, during the last half century, coal preparation engineers have repeatedly sought methods for evaluating the technical and economical efficiency of separating coal in coal cleaning equipment and for predicting the quantity and quality of cleaned coal produced, as well as profit- ability for the entire plant. Many formulas have been proposed by investigators to evaluate the efficiency of various coal cleaning operations. Performance criteria in use today are capable of defining all of the important aspects of a given concentrating operation; however, each criterion has certain restrictions or limitations. It is important, therefore, to understand how such formulas can be used and the problems involved in their construction. Technical Measures of Equipment/Plant Performance Conventional measures for evaluating the performance of a preparation plant are generally the same as those used to evaluate equipment performance. Measures involving separation efficiencies are influenced by the following three broadly encompassing primary factors: (1) density composition of the feed coal, (2) design characteristics of the cleaning unit, and (3) relative density of the separation. Since separation efficiencies are dependent on factors involving the nature of the coal, they are termed dependent criteria and represent a very broad technical indicator of an individual process or plant performance. Performance measures known as independent criteria are influenced mainly by quantitative errors inherent in the design and operation of the processing equipment. Economic Measures of Plant Performance True assessment of coal cleaning methods require reference to economic measures such as profitability. During the years in which technical efficiency criteria for characterizing plant performance were being improved, coal preparation engineers were also seeking appropriate economic criteria to assess plant performance. Technical and economic effectiveness of plant performance are important parameters for coal preparation flowsheet design. The relationship of the technical and economic parameters can be formulated in an economic model and mathematical model with the aid of computers. The computerized models

Jan 1, 1991

By Scott G. Britton

This chapter discusses the necessary construction techniques for installing coal mine ventilation devices. Included in the discussion are the major air controlling devices called over- casts, regulators, stoppings, and doors. Under-casts, although a valid device, are used infrequently in coal mining and are not discussed here. Typically, coal mines require a great many ventilation devices to control the air movement. Post-I969 mines have had to design their air systems to comply with the Federal Coal Mine Health and Safety Act (CMHSA) as discussed in Chap. 1. Pre- 1969 mines have had to redesign major portions of their systems to comply with the basic components of the law such as separation of air courses, single unit split ventilation, and minimum air quantities. It is not uncommon, therefore, to find a large mine (2.0 Mt/a) requiring several hundred overcast installations (permanent, as well as repeat construction), plus doors and regulators placed among a thousand or more stoppings. When each of these devices is subject to leakage from installation and weathering defects, the importance of effective construction becomes evident. An historic rule of thumb for average mine ventilation says that about 70% of all the air pressure generated by the mine fan is lost between the portal and the working faces. Of course, this rule is subject to many factors, but the message is clear: there is a tremendous inefficiency in controlling leakage through common air devices. This chapter strives to present a standard approach and design alternatives which can go a long way in reducing this leakage, and hence, ventilation costs. Historically, mine ventilation has progressed from natural, or draft ventilation, to fire-induced ventilation (Fig. l), furnace-fired centrifugal fans and finally, to today's modem mine fans. Underground controlling devices have been in use in the coal mines since the late 1600s, but the CMHSA of 1969 was the real turning point for mine ventilation. Minimum quantities and velocities of fresh air were required for mining, forcing coal operators and engineers to reevaluate and improve their systems. As a consequence, the cost for ventilating air increased. Today, companies face a variety of choices among design alternatives, materials, labor, and costs of ventilating devices for their mines. The best approach for any individual company or mine is determined by (1) the needs of the mine, and (2) the local design parameters. In my discussions of ventilation construction I shall be fairly general in terms of device installation steps, where specifics are warranted for clarification, I will include this information.

Jan 1, 1983

By Edward K. E. ] [Williams

Conditioning is any treatment of an ore with or without reagents which affect its floatability. While it can start in crushing or grinding circuits and continue into the flotation circuit, conditioning will refer here only to reagent treatment in an agitated tank designed for the purpose. Such treatment is often unnecessary with sulphide ores and collectors or with amines,* but it has long been recognized as essential with fatty acid collectors in the flotation of non-sulphide minerals, The requirements can be extremely variable, depending upon ore alteration, the presence or absence of slimes, and 1 the minerals to be separated. The study described here was concerned with the recovery of oxidized molybdenum minerals from an ore containing the element in both sulphide and oxidized form. Flotation of the iron minerals with which the oxidized molybdenum was associated was the basis for the process. Recovery and optimum concentrate grade without desliming depended upon a twenty to thirty minute conditioning of the pulp with flotation reagents at forty to fifty percent solids and at high turbulence. The objective in the study was the determination of design and operating criteria for conditioners in order to permit scaling-up of the results without repeating the entire study on a larger scale.

Jan 1, 1968

By R. W. Draves

Planning and testing in advance of the mining operation are essential. This advance work can involve physical and chemical analysis of overburden cores, field test plots, green- house studies or any of a multitude of other baseline data collection activities. This paper presents the results of Central and South West's field test plots and how they relate to topsoil substitution. Besides the obvious need for testing in advance of mining, there are the inevitable regulatory requirements. Quoting from the office of Surface Mining Regulations concerning topsoil substitution: 216.22(e) TOPSOIL SUBSTITUTE AND SUPPLEMENTS -Selected overburden materials may be substituted for or used as a supplement to topsoil if the office determines that the resulting soil medium is equal to or more suitable for sustaining revegetation than is the available topsoil and the substitute material is the best available to support revegetation.

Jan 1, 1985

By C. Manea

During exploration and exploitation of complex ores, waste dumps that contaminate severely the environment and in particular soils, are genetated. The most hazardous pollutants are heavy metals and metalloids (e.g As, Mo, Pb and Cu) as well as radionuclides (e.g U and Ra). Ecological remediation aims, among others, at decontamination of soils by preserving important properties as soil fertility.

Jan 1, 2008

By Robert C. Freas, Donald D. Carr, Lawrence F. Rooney

Perhaps no other mineral commodities in this volume have as many uses as limestone and dolomite. These carbonate rocks are the basic building blocks of the construction industry, the material from which aggregate, cement, lime, and building stone are made. Carbonate rocks, and their derived products, are used as aggregates, fluxes, glass raw material, refractories, fillers, reactive agents in sulfur-oxide removal, abrasives, soil conditioners, ingredients in a host of chemical processes, and much more. Although the use of limestone and dolomite goes back before recorded history, new uses and products are continually being found. Carbonate rocks form about 15% of the earth's sedimentary crust and are widely available for exploitation. Found extensively on all continents, they are quarried and mined from formations that range in age from Precambrian to Holocene. Reserves of carbonate rock are large and will last indefinitely, although high-purity deposits may be absent or have limited availability in certain areas. Limestone and dolomite are so useful and so abundant that in 1989 about 798 Mt were produced in the United States. In fact, about 75% of all stone quarried or mined in the United States was carbonate rock. Sand and gravel was the only mineral commodity produced in greater quantity. In this chapter we have sought to provide the general reader an overview of carbonate rocks, their composition, distribution, production, and uses. The literature on the limestone and dolomite resources of the United States and Canada is so vast and diverse that one can easily become mired in print. We tried to list those references that are easily accessible and that provide the economic geologist with a starting point for more intensive study. The table listing selected references on limestone and dolomite resources in Canada and the United States reflects our attempt to be selective rather than exhaustive and to direct the reader to the best sources of detailed information.

Jan 1, 1994

By Dennis Molvik, Omar Fulton, Chris D. Breeds, Don Gonzales

The Tolt Pipeline No. 2, West Snoqualmie Valley project, is part of a water supply project linking the Tolt reservoir in East King County to the City of Seattle through a nominal 2.13 m (7-ft) inside diameter conveyance. Receipt of the National, 2002Microtunnel Award provided recognition of the many challenges overcome by this project. Baseline conditions revealed in the Geotechnical Documentation included over-consolidated glacial deposits, landslide and alluvial deposits, artesian water, boulders up to 36-in in diameter, logs, heaving sands, and liquefiable soils beneath the river. Schedule constraints associated with setting the shafts in the floodplain of a salmon bearing river and the fickle performance of the river during those times it was not supposed to flood added to the challenge.

Jan 1, 2003

By Marshall D. Himes, Erich U. Petersen

The Sheep Creek deposit near White Sulfur Springs, Montana, is a middle Proterozoic stratabound and strataform sediment- hosted massive sulfide containing 4.5 million tonnes (5.0 million tons) averaging 2.5% copper, and 0.1% cobalt in the upper sulfide zone (USZ) and 1.8 million tonnes (2.0 million tons) averaging 6% copper in the lower sulfide zone (LSZ). Mineralization is hosted in lower Newland shales and debris flow conglomerates in the graben controlled Helena Embayment of the Belt Basin. USZ mineralization is characteristically high in Cu, Co, Ni, Ba, As, Pb, and Ag. Mineralogically it consists of barite, pyrite, chalcopyrite, and tennantite with minor amounts of marcasite and various cobalt minerals. By contrast, the LSZ is higher in Cu, Ni, and Au and lower in Co, As, Pb, and Ag. Mineralogy of the LSZ consists of dolomite, pyrite, and chalcopyrite. In both zones significant amounts of cobalt, nickel, arsenic and copper are incorporated in pyrite rims. Tennantite controls the abundance of numerous trace elements in the ores. Fluid incluison data from hydrothermal USZ barite suggests that mineralization took place at temperatures in excess of 250°C, under relatively oxidizing conditions (f02 = 10-32+1) from moderately saline (1.1-3.5m), metal rich brines. The absence of barite in the LSZ suggests mineralization under more reduced conditions (f02 = 10.38+2). Mineralization was initiated following basin subsidence in excess of 400m. Contemporaneous with movement along a growth fault(s) was upward migration of hot metal-bearing fluids which permeated the loosely consolidated sediments and may have vented on the sea floor. The differences in the two zones may be explained by the effects of variations in local basin morphology and solution chemistry.

Jan 1, 1990