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By Fathi Habashi

A LARGE number of metals are found in nature, in rich deposits, in the form of sulfides as shown in Table 4.1. Treatment of sulfide ores is done mostly by pyrometallurgical operations; it is only recently that hydrometallurgical processing started to compete with pyrometallurgical methods.

Jan 1, 1970

By Alan R. Grant

Interpretation of presently available geological information indicates that most of the periods of significant metal deposition in the Washington Cascades Range are, at least in part, genetically related to late Cretaceous -Tertiary intrusive episodes. Chemically, the most favorable environment for base metal deposition is high in potassium. Characterizing the advanced stages of these chemical alteration conditions are the silicate mineral assemblages orthoclase and/or secondary biotite. Wall rock alteration includes both deuteric and hydrothermal processes, the intensity of which primarily depends upon the degree of fracturing in the country rock prior to the introduction of secondary material. Broadly speaking, the primary physical controls for the distribution and concentration of sulfides appear to be a series of structural couples involving both northwest (paralleling regional trends) and northeast--striking systems. Meaningful base metal exploration in the Washington Cascades demands a basic understanding of the various geologic factors related to the distribution of the sulfide deposits. Any geologist contemplating Cascade work should be well grounded in the fundamental concepts of petrology and structure.as these constitute two of his most beneficial aids. The acquisition of the detailed data necessary for this understanding may seem a bit academic, yet it has been demonstrated in numerous instances that a fair economic appraisal of a particular property or mining district depends primarily upon the ability of the geologist to recognize the subtle environmental differences which could lead to the discovery of a major ore deposit.

Jan 1, 1971

By D. A. Norrgran, J. N. Orlich

Described is the application of high- intensity magnetic separation throughout the spectrum of industrial minerals. Performed either wet or dry, the separation has application in both the recovery and concentration of value minerals and in removing deleterious mineral constituents. The various types of magnetic separators along with the design and operating parameters relative to separation response are characterized. The characteristics of specific minerals to magnetic collection and the production of high-grade concentrates are described. Laboratory, pilot-scale, and plant studies carried out on a variety of industrial minerals have demonstrated the effectiveness of magnetic separation as either a primary or a secondary unit operation to achieve product quality.

Jan 1, 1987

By Melvin W. Kraschnewski

In 1966 Central Ohio Coal Company and Bucyrus-Erie signed a contract authorizing Bucyrus-Erie Company to design and build a 220 cubic yard dragline. This dragline would be used for stripping overburden from their coal reserves located near Cumberland, Ohio. The size of the machine was arrived at after a thorough application study of their annual coal output requirement, depth of overburden and type of terrain. The design and construction of this machine which has been designated by BECO as model number 4250-W is the title of this paper. Size wise based on machine weight the 4250-W represents an increase factor of three over our largest current dragline. Probably the easiest way of presenting a machine of this size is to build it from the bottom up.

Jan 1, 1969

By L. E. Bowman

Efficient filtration of fine kaolin particles plays a crucial role in processing of raw kaolin to a marketable product. Oftentimes, filtration Is the rate controlling step of the whole process. As a consequence, plant production is dependent, to a great extent, on the rates being achieved In filtration. In order to alleviate the bottleneck in production, Nalco Chemical Company initiated a reagent development program to chemically enhance the performance of the filtration units. Filler aids of different classes were synthesized for evaluation. These include reagents whose primary mode of functionality were: coagulation, flocculation, thickening, and combinations of the preceding. All reagents that were synthesized and tested were listed under the appropriate Food and Drug Administration sections of the Code of Federal Regulations. This paper discusses the development and application of a new reagent that Improves the filter production rate with minimal Impact on filter solids. The results of laboratory filter studies along with plant data are presented and discussed. Plant data indicate that this reagent is capable of increasing production rates by as much as 35% on various clays of coarse particles to the finest fractions, as well as clays that are calcined. The reagent's Impact on solids content, re-slurrying characteristics, Brookfield and Hercules viscosity, and drying is within the standards set by plants who have evaluated and now use this product.

Jan 1, 1993

By M. Xing, S. Usman, K. Awuah-Offei

"While mines generally focus on achieving operational efficiency, creating shared value for all stakeholders is also a management goal. This includes taking a holistic view of their supply chains and increasing local participation. This paper examines the role of supply chain management in mine management; in particular the effect of a strong local supply chain on regional economic impacts. Using input-output analysis, the impact of a local supply chain on a mining sector’s regional economic impact is examined by increasing local sourcing (increasing local purchase percentage -- LPP) for 10 key commodities. An approach, based on multipliers and excess local capacity is used to identify key commodities. The impacts examined are sales, employment, labor income, and value added. The work is illustrated with stone mining and quarrying in Missouri. Ten percent increases in LPP of the key commodities, in this example, result in $4.1 million additional impact on the Missouri economy. This work can provide insight on how to better create shared value for all stakeholders. INTRODUCTION Little research has been published on improving mine supply chain management (SCM) to enhance regional economic impacts. Although some extensive academic research has explored the importance of an industries’ supply chain, not much is known about how a locally-based supply chain increases shared value in the resource sector. Across industries, traditional SCM is getting more and more complex. This is true of the mining sector as well. However, this increased sophistication is not directed towards increasing shared value for all stakeholders, particularly, the local communities. Further research is required to develop new SCM strategies that enhance local participation. One major point of difference between this work and traditional supply chain management is the inclusion of stakeholders’ shared value as a goal in SCM. Creating shared value has become a business goal in recent years (Porter and Kramer, 2011). The authors use input-output analysis (Leeuw, 2012) to evaluate the regional economic impacts of supply chain decisions, which is not part of traditional SCM. Although input-output analysis has been applied to SCM for decades, most of the research uses input-output analysis as a tool to advance an industries’ own operational efficiency (Accenture, 2014)."

Jan 1, 2015

By Gregory E. Korbin

The effectiveness of pre-reinforcement as an immediate stabilization measure as well as its contribution to the permanent stabilization of a tunnel were studied through the use of physical (Figure 1) and numerical models (1). Physical models were designed for the investigation of two pre-reinforcement systems: first, reinforcing far ahead of the main excavation (Figure 2); second, spiling reinforcement ahead of the face (Figure 3). In both cases, the use of reinforcement was responsible for permanently stabilizing an otherwise unstable opening. Data from the physical models were used to calibrate a numerical model from which additional information on long term behavior, methods to account for the capacity of a pre-reinforcement system, and the mechanisms involved were ascertained. These studies indicated that pre-reinforcement can stabilize a rock mass effectively as it reduces deformations and thereby deterioration due to strain softening, provides rock mass confinement leading to increased available strength, and maintains rock arch continuity allowing for increased tangential stress in the immediate vicinity of the opening. Field studies verified the capacity of spiling reinforcement to restrain initial deformations.

Jan 1, 1976

By M. D. Chatham

Revolutionary electronic monitoring and control systems provide a gold mine of diagnostic and prognostic information. Lower cost per ton results from timely operator action, increased visibility of information to production and maintenance personnel, and better fleet management. When information is effectively integrated into fleet management systems lower costs result from higher availability, longer component life and reduced repair cost. This paper will present the objectives of the Caterpillar Vital Information Management System (VIMS) and provide actual examples of successful use.

Jan 1, 1995

By A. Iordanidis

Mining activities have recently been taken place in Vourinos mountain, northern Greece, exploiting the so-called ?olivinite?. A representative sample was collected from this mining area. Mineralogical analysis was conducted using X-Ray powder Diffraction (XRD). A thin section was prepared and analyzed under optical microscope. X-Ray Fluorescence (XRF) was employed for the chemical analyses of major, mi-nor and trace elements. Environmental Scanning Electron Microscopy coupled with energy dispersive x-ray analysis system (ESEM-EDX) was also applied for the characterization of the sample. Forsterite (Mg-rich olivine) and enstatite (Mg-rich orthopyroxene) were the main mineral phases determined by XRD, with a 56% and 44% content respectively. Trace amounts of chromite spinels were also determined. Based on this characterization, the industrial rock proved to be a hartzburgite (a type of peridotite in petrological terms). Optical microscopy and ESEM-EDX provided similar observations and confirmed the above-mentioned results. XRF revealed a composition of 43.31 MgO, 44.25 SiO2, 9.98 Fe2O3, 1.40 CaO, 0.67 Al2O3, 0.22 MnO, 0.01 TiO2 and negligible amount of LOI (<0.1%). Trace elements with high concentrations were Cr (2678 ppm) and Ni (2044 ppm). The comprehensive characterization of this mining product suggested the suitability for various uses, such as refractories, foundry and slag conditioner. Additional experiments are being carried out for environmental applications, e.g. wastewater treatment.

Jan 1, 2006

By Jan Visman, James W. Parkinson

GENERAL INTRODUCTION Sample collection, preparation and analysis are all steps in a single process designed to provide information about a much larger amount of material than the sample itself. For example, information about the ash content of a unit train load of coal may be derived from a single, relatively small sample of perhaps a few hundred pounds (liters) extracted from the entire shipment. These three steps can be thought of as links in a chain, allowing the simple analogy that the strength of the chain, or, in other words, the value of the information is only as strong as the weakest link. Sample collection, discussed in Part 1 of this chapter, is critical because analytical procedures can do no more than reveal the characteristics of the sample presented to the laboratory. If that sample does not properly represent the population to be characterized, neither will the analysis of that sample. Sample preparation is also a critical part of the chain. Any change in the nature of a sample between the time it is collected and the time it is analyzed will appear to reflect the nature of the population. For example, sample preparation procedures that allow air to partially dry the coal sample before reaching the laboratory will cause the sample analysis to indicate a lower moisture content than the sample originally had. Other changes can be more subtle. Second only to moisture loss, oxidation reactions generally cause the greatest problems. Oxidation of a coal sample can alter surface properties, changing flotation response. In extreme cases, combustion parameters, such as caking or agglomerating properties or mineral composition, such as pyrite content, can change. Water samples can also be altered by oxidation. For example, ferrous iron can oxidize to ferric iron, possibly changing water quality parameters such as pH. Sample analysis, the subject of Part 2 of this chapter, is the final link in the chain. Obviously, no laboratory procedure can correct for problems created by improper sample collection and preparation. At the same time, poor analytical techniques will create incorrect information about the total amount of coal from which the sample was extracted (the population) in the same manner as improper sample collection and preparation. The key to gaining correct information about the population is to view these three steps as parts of a single process. Following proper techniques through only one or two steps of the process will not produce accurate information.

Jan 1, 1991

By S. Chander

The mechanism of oxidation of sulfur in pyrite is a function of the rate and driving force for oxidation. New evidence is presented in this article to show that at moderate potentials, a sulfur-rich hydrophobic layer is formed. Under ordinary conditions, the sulfur layer is covered with a layer of iron oxides, hydroxides, sulfate or oxy-sulfide ions. Under these conditions, pyrite is hydrophilic. In the presence of iron-chelating agents or iron sequestering ions, iron layer might not form. Under these conditions, sulfur-layer is exposed and pyritic might become hydrophobic. Stronger oxidizing conditions decompose the sulfur-layer, thereby making the surface hydrophilic.

Jan 1, 1992

By N. Damiano, J. Noll, C. Zhou, J. DuCarme

"Preventing machine-related injuries is one of the major safety concerns in underground coal mines. Severe injuries and fatalities occur when a miner is struck, crushed, or pinned by mining equipment such as a continuous mining machine (CMM), shuttle car, or a scoop. Proximity detection systems (PDSs) have been applied in mining to reduce these types of injuries and fatalities. All of the PDSs that are currently approved by the Mine Safety and Health Administration (MSHA) for use in underground coal mines are magnetic-field based and could be affected by metallic objects such as trailing cables. Researchers from the National Institute for Occupational Safety and Health (NIOSH) investigated the influence of trailing cables on the performance of PDSs. In particular, the magnetic field coupled from proximity system generators to a de-energized trailing cable were characterized. The results show that significant energy can be coupled from the proximity system generators to a trailing cable when there is a closed loop in the cable. The effect on PDS performance from the magnetic field radiated around an energized trailing cable was also quantified for different current amplitudes in the cable. It is shown that the magnetic field caused by the electric current in the trailing cable mainly consists of a 60-Hz signal and its harmonics which cause little interference to the PDS. The results presented in this paper can help PDS manufacturers to design better systems that are more immune to these effects. INTRODUCTION An average of 250 injuries occur every year during operation of Continuous mining machines (CMMs), and 43 miners have been killed by striking or pinning accidents involving CMMs in the U.S. from 1984 to 2015 (Mine Safety and Health Administration, 2015). In addition, there have been 10 fatal accidents involving mobile haulage equipped with trailing cables from 2000 to 2015 (Noll et al., 2017). In response to these fatalities and injuries the Mine Safety and Health Administration (MSHA) promulgated a regulation in 2015 requiring the use of a proximity detection system (PDS) on all CMMs except full-face machines and proposed a regulation in 2016 which would require a PDS on other mobile underground equipment. Current PDSs approved for underground use are magnetic-field based. The PDS contains machine-mounted magnetic field generators that create fields around the machine. The other part of the PDS is a miner-wearable component (MWC) that reads the flux density of the generators. These systems use the magnetic field strength readings from the MWC to determine whether a miner is at a safe distance from the machine. A stable magnetic field is essential for the accuracy of the system."

Jan 1, 2018

By Roy L. Klein

The production of synthetic fuels from coal has been pioneered by South Africa. South Africa made a decision in 1975, due to the threat of an oil embargo, to proceed with the construction of Sasol Two, then followed by Sasol Three. South Africa has large coal but little indigenous petroleum reserves. The indirect coal liquefaction process used by Sasol since 1955 is the only commercially demonstrated method available for producing transport fuels from coal. The new plants consume 27 million tons per year of coal from a single mine that now produces transport fuels in sufficient quantities for energy independence.

Jan 1, 1983

By G. Blackwell

In the 1980&apos;s the Canadian surface mining industry was confronted by declining competitiveness in the face of low cost foreign producers and alternative materials. Low metal prices undermined profits for many mining companies. Restructuring, rationalization, capacity reduction, technology transfer, as well as favourable currency rates and higher commodity prices, helped revitalize the industry by the close of the decade. Now in the 1990&apos;s, however, the need to improve competitiveness for profitability has re-emerged in greater intensity. In the current climate it is considered that there are three strategies available to industry to ensure profitability: continued rationalization and restructuring; optimization of operating practice; and technology development and transfer.

Jan 1, 1993

By J. B. Mitchell

Comminution methods for base metal and precious metal ores have had considerable attention from mine operators, equipment suppliers and design engineers for many years and much of their work has been well reported. This interest derives from a healthy concern with the costs of comminution, often the largest single cost factor in ore dressing of hard ores. Many imaginative innovations have resulted. One notices a trend toward autogenous and semi-autogenous methods, combined with a trend toward very large equipment. Unfortunately, there has been less obvious cost incentive to experiment with softer ores. This is unfortunate because the consequences of inappropriate comminution methods can have an important effect on overall economics by influencing down stream processing and salability of final products. This paper concerns some of the factors to be considered in the selection of comminution methods for potash ores, and gives some specific examples to illustrate some of the principles involved.

Jan 1, 1969

By D. Farnell

Large semi-autogenous (SAG) or autogenous grinding mills have become the work-horse of the modern high volume concentrator. They typify the economy of scale - fewer, larger machines doing more work, more economically. With fewer machines, equipment reliability becomes of paramount importance. Realizing this, companies installing new or modernizing existing facilities have placed extraordinary emphasis on purchasing a reliable mill. This, in turn, has had a significant impact on mill design. Kennecott And Codelco - Two Different Approaches Last year, two of the world&apos;s largest copper producers, Codelco and Kennecott, undertook the modernization of their main grinding facilities at Chuquicamata and the Utah Copper Division (UCD) respectively. Both selected semi-autogenous milling and both, recognized the importance of the reliability of the primary mills. Each, however, decided on a different approach to optimizing reliability. Codelco placed the emphasis on technical innovation in design and opted for a gearless driven mill. Kennecott chose the more conservative approach of active participation and exceptional quality assurance in mill design and manufacture.

Jan 1, 1987

By Frank P. Traczyk

INTRODUCTION The process of solid-liquid separation can be an important decision in plant design. It is very important that one must consider not only the most effective means of solids-liquid separation, but also to consider the effects on upstream and downstream processes. A solid-liquid separation is done either to remove the solids £ran the liquids as in copper concentrates or rave a liquid from the solids as in uranium operations. In either case, washing can be an important consideration to clean the solids or recover the liquids. This section will deal with solid- liquid separation other than thermal, sedimntation processes, or hydro cyclones. The three major areas discussed are pressure filters, vacuum filters, and centrifuges that are most cannon in the minerals industry. PRESSURE FILTERS Pressure filters are one common type of solid-liquid dewatering devices. There are my different types of pressure filters that are both continuous and batch operations. They are characterized by using an external pressure to push or force the slurry through porous media to force the liquids out of the solids. Whereas vacuum filters are limited to one amsphere or bar working pressure, some types of pressure filters operate as high as 16 bars pressure. Pressure filters are also effective for hot slurries where a high boiling point can be a problem or precipitation occurs under vacuum. The types of pressure filters most common in the mineral processing industry include plate and frame and recessed plate filters. Some of the new technologies including automatic pres- sure filters and belt presses are also discussed. Plate Frame Filters Plate and frame filters are one of the oldest and most effective means of both dewatering solids and clarifying liquids. Plate and frame filters consist of a skeleton that is used to hang or support alternate plates and frames that are pressed together to form chambers. The filter plates consist of a drainage grid that is covered by sane type of filter media through which a liquid is

Jan 1, 1986

By V. N. Kolesnikov

The gold-silver deposits of the northern Primorye region are located in the eastern part of the East Sikhote-Alin volcanic belt, where the belt overlaps the Kema island-arc terrain of the Aptian-Albian age. There have been four deposits and numerous mineralization points found in the NE-trending Kema metallogenic belt that is about 1000 km long and 100 km wide. The known mineralization is of epithermal type, controlled by faults, and concentrated in quartz, quartz-fluorite-adularia, and, less commonly, sulfide-quartz vein systems hosted by the Upper Cretaceous-Lower Tertiary volcanic rocks. The vein systems extend for hundreds meters along strike, varying from tens centimeters to 50-60 meters in width. They are surrounded by wide zones of low-temperature hydrothermal alteration containing some gold-silver mineralization for which the commercial value was not studied during the early exploration. The ore bodies contain from 1 to 50-80 ppm of Au and from 1 to 1000 ppm of Ag. Gold is native, associated with quartz, and represented by particles from tens of microns to 1 mm in size. Silver occurs in native form as a constituent of argentite, pyrargyrite, stephanite, and other sulfosalts. The test work carried out for three vein systems 20 years ago showed that gold might be easily and almost completely recovered from the ore by cyanide treatment. The paper describes the geology and mineralogy of the deposits, Salut and Primorskoye, that are the most studied properties of the Kema belt. It also presents the data available on disseminated gold-silver mineralization in stockworks, altered explosive breccias, and wide zones of low-temperature hydrothermal alteration. This mineralization should be explored for possible exploitation as large open-pit, heap-leach deposits.

Jan 1, 1998

By B. Denby, R. Hollands

Mine information is often multi-disciplinary, dynamic and spatially complex. Different departments use the same data in many different ways, information changes over time and mines change their shape continuously. Earthworks InTouch is a radical VR-based system developed by AIMS Solutions and marketed by Earthworks, which provides a rapid and intuitive interface to a wide range of mine information. VR is used to provide an interactive and visually accurate, dynamic 3D model of the mine workings and equipment operating in the mine. Individual objects in the mine can be linked to external applications that provide up-to-date and context sensitive information. Equipment movement can be simulated or tied in to real-time survey from GPS systems for example or excavator productivity data can be extracted from a production database. The paper will highlight the major advantages of using such a VR interface to access valuable and time sensitive information.

Jan 1, 2002

By Arun Patel, Diane Hirsch, Pamela Moran

The Metropolitan Washington Airports Authority (Authority) has undertaken a tremendous expansion of Washington Dulles International Airport in Fairfax, Virginia, including upgrading passenger transportation between concourses. The first stage of this expansion envisioned a shallow cut-and-cover pedestrian tunnel between the Main Terminal and Concourse B with associated vertical circulation structures. At the beginning of the design contract, the Authority’s consulting team of Earth Tech, formerly Kaiser Engineers, and the Dr. G. Sauer Corporation compared the cost and disruption of constructing the tunnel as a cut-and-cover structure to mining the tunnel using the New Austrian Tunneling Method (NATM). Upon review, the Authority endorsed the latter method.

Jan 1, 2003