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By K. E. Doud

An unusually pure grade of rutile and several grades of aplite rock are produced in a unique mining and mineral dressing operation in Hanover County, Virginia. The ore body is an aplite rock of gnessic structure, having a sari ace exposure extending over several hundred acres, heavily leathered and containing rutile, ilmenite, and other titanium and iron minerals. The physical nature and mineral composition of the ore body has permitted the use of a relatively economical and unusual processing circuit. The flowsheet was designed to take full advantage of the remarkable liberation of the minerals at relatively coarse rinds. It permits flexibility in changing the product mix, and maintains high levels of purity in both rutile and aplite rack. The mineral processing is discussed in some detail below.

Jan 1, 1962

By Edward M. Jacobs

In some ore grinding circuits it is desirable to make separations purely on size. The normal choice for this is vibrating screen equipment. Developments in screening process technology have led to improvements in the capacity and efficiency of vibrating screens, through the adoption "Thin Layer Wet Screening". This process can reduce recirculating loads and equipment requirements in the ore grinding circuit.

Jan 1, 1985

By José A. Matar Ibañez

Geologic terranes in Argentina include potential mineralized environments from localized younger Precambrian cratonic outcrops through Paleozoic sequences, generally in the northwest or under younger cover, to the Mes[o] zoic-Cenozoic Andean Systems in western and southern Argentina. Argentina is self sufficient or nearly so in many metallic, nonmetallic, and energy commodities, and exploration in each of these categories is ongoing. Present production of precious metals (silver and gold) is important, and many recent discoveries of base metals, precious metals, alloy metals, and other mineral categories have been made. Economic trends, geologic environments, and commodity types important in actual exploration are described, and it is emphasized that extensive areas showing attractive alteration, geochemical, and geological anomalies, especially of porphyry, cordilleran vein, and epithermal characteristics, remain to be fully evaluated.

Jan 1, 1986

By Kousik Sinha

The advantage of using a clean coal as a feedstock in a direct liquefaction plant is improved performance of the plant by several factors e.g., increased throughput of coal; reduced wear and tear of valves, pipes, and pumps; increased liquid yields, etc. This paper examines the technical feasibility for cleaning Illinois #6 coal as a feedstock to a direct coal liquefaction plant via selective agglomeration using a coal-derived heavy distillate, Wilsonville V-1074 as agglomerant. Effects of addition of Kerosene or coal-derived Naphtha as conditioner, coal particle size, slurry pH, oil to coal ratio, and operating temperature on ash reduction and clean coal weight recovery have been studied. Results show that about 70% of the ash can be removed from this coal and the clean coal weight recovery over 85% can be achieved by using this technique with suitable selection of coal particle size, slurry pH, mixing intensity and oil to coal ratio.

Jan 1, 1991

By J. Richard Kyle

Salt domes, their cap rocks, and the adjacent sedimentary strata represent a major economic resource in the Gulf of Mexico basin. Gulf Coast salt diapirs formed in response to sediment loading of the "mother" Louann evaporite sequence of middle Jurassic age, an effect that is caused by the buoyant nature of the lower density salt. Halokinesis progresses from nonpenetrative deformation that creates broad "pillow" structures into discrete high-amplitude diapirs. Because of its buoyancy, the top of the salt diapir remains near the land surface or the seafloor during much of its history as the basin floor subsides. The salt within the Gulf Coast diapirs is deformed complexly and commonly shows subvertical banding that represents modified sedimentary layers with different contents of nonhalite components. The most abundant impurity is anhydrite, which occurs as individual millimeter-scale crystals or as deformed clasts that generally form about 5% of most salt stocks. Many mature salt diapirs are mantled by a "cap rock" that consists of a lower anhydrite zone and an upper calcite zone, commonly separated by a discontinuous gypsum-bearing zone. The anhydrite zone forms as accreted layers of anhydrite grains and clasts that are left after episodes of halite dissolution. The calcite zone is a product related to petroleum destruction accompanying bacterial reduction of aqueous sulfate. Calcite-cemented siliciclastic strata occur above or alongside diapirs. The mineral resources of the salt-dome setting are remarkably diverse. Major economic products of the salt-dome environment are salt and cap-rock-hosted native-sulfur deposits, as well as petroleum resources that occur on the dome flanks and in the cap rock. Native sulfur forms as a result of bacterial sulfate reduction accompanying petroleum destruction to form hydrogen sulfide, which is subsequently oxidized to elemental sulfur, major amounts of which have been produced by the Frasch process from Gulf Coast salt-dome cap rocks. Some cap rocks have produced limestone, gypsum, and anhydrite for a variety of construction uses. Although traditional industrial-mineral resource production from Gulf Coast salt domes is shrinking, some cap rocks host potentially commercial concentrations of celestite and barite, as well as the metals Zn, Pb, and Ag. Furthermore, caverns, excavated within the salt stocks, serve as major storage facilities for crude oil (including the Strategic Petroleum Reserve), liquefied petroleum gas, and natural gas. These resources are products of fundamental geologic processes that are integral to the evolution of the Gulf of Mexico basin. Whereas production of some industrial-mineral resources, such as elemental sulfur, has declined in recent years, ample reserves of salt will allow production to continue into the foreseeable future. Further, there is potential for other mineral-resource production from cap rocks under favorable economic circumstances. Expanded use of caverns, excavated in the salt masses for material storage and disposal, is likely to continue into the next century.

Jan 1, 1999

By Gary Buchan

During several months in 1996 and 1997, Cyprus Twentymile Coal Co. (TCC) set world production records at its Twentymile Mine in northwestern Colorado. These records were due to the company's implementation of a state-of-the-art longwall mining and conveyance system along with a -highly dedicated work force. This article is a case study of the design of long panels at the mine from conception to implementation. Obstacles that needed to be overcome included subsidence engineering, environmental regulations, conveyance, ventilation, equipment design and continuous miner (CM) development timing.

Jan 1, 1998

By J. J. Moore, I. Iwasaki, L. A. Lindeke

Correlation of scale-up from small-scale batch laboratory mills to large-diameter industrial mills was established by performing two series of laboratory and pilot plant grinding tests using a magnetic taconite ore and a siliceous sulfide ore. In one series, controlled batch grinding tests in 203-, 508-, and 914-mm (8-, 20-, and 36-in.) diameter mills were carried out followed by a second series involving continuous grinding tests using 305-mm (12-in.) and then 1067-mm (42-in.) diameter pilot plant ball mills in open circuits. The effects of ball diameter on wear and of mill diameter on grinding power and ball wear are illustrated.

Jan 1, 1988

By S. A. Matthews, M. L. Nave

AC variable frequency motor drives are emerging technology for belt conveyors. The success of the application in mining depends on adequate and timely consideration of drive, motor, and conveyor features. The purpose of this paper is to familiarize and inform possible mining users of AC variable frequency drive attributes.

Jan 1, 1998

By William G. Freeman

As with most industrial minerals, barite is freight sensitive. This paper is given so that others might gain from the experience of barite companies in reducing their transportation costs. Some of the approaches used were unusual and others standard, but by perseverance considerable savings were realized.

Jan 1, 1973

By D. S. Cavers

INTRODUCTION This paper discusses aspects of rock engineering applicable to surface gold mines. Discussion particularly centers on areas in which rock mechanics can enhance the mine productivity or profit- ability. Methods of analysis are discussed briefly but for more detai1s the reader is referred to the appropriate references. A team approach to the overall design of the pit generally pro- duces a better result at an overall lower cost. In particular, money is wasted by asking for a "report on slopes" and then input- ting this slope angle into a pit design and economic analysis study without further reference to the geotechnical engineer. Pit slope angle depends on slope orientation, location, pit shape, pre-existing discontinuities and mining methods. Preliminary slope angles can be produced but optimization depends on ongoing inter- action between the mining engineers, geologists and geotechnical engineers. This interaction can a1 so substantially reduce overall design time which may be critical in bringing remote plays into production. Most surface gold mines in North America are in igneous or metamorphic environments. Rock mechanics aspects discussed in this paper will be discussed with reference to these environments al- though most of the principles and comments are applicable to sedimentary environments as we1 1.

Jan 1, 1987

By Wayne W. Murdy

Since 1993, Newmont Mining has been growing through the development 'q of three major foreign mining operations with a fourth under construction. The first project, Yanacocha in Peru, began operating in October 1993. This occurred at a time when political and business risk in that country was considered high. In 1995, Newmont began operating the Muruntau joint venture in Uzbekistan. It is the first mining project of its kind in the Confederation of Independent States (CIS). In early 1996, Newmont started operating the Minahasa Mine in Indonesia. In early 1997, Newmont began construction of a $1.9-billion project in Indonesia. The company is also completing a feasibility study with its partner for the development of a gold operation in Mexico. All of these projects have been considered "risky" by most standards. Newmont has been successful in all of them through risk mitigation programs. These programs include using strong and successful in-country partners, concentrating on developing a strong national workforce with minimal expatriate employees, using World Bank, European Bank for Reconstruction and Development (EBRD) and International Finance Corp. (IFC) financing and building and maintaining strong ties with host governments.

Jan 1, 1997

By E. Rigopoulos

Mining disturbs the environment, even when the ores or the minerals extracted are non-toxic. Silver & Baryte Ores Mining Co S.A (S&B) is committed to minimizing the environmental impacts of its mining activities, by implementing an integrated rehabilitation program wherever it operates. The paper discusses the principles for mining-disturbed land restoration activities on Milos Island for a successful outcome.

Jan 1, 2003

By D. Piper, J. Noble, M. Richardson, J. Wojcik, L. W. Cope

L. Cope Welcome. I am pleased to see so many people interested enough to stay until this last session of the last afternoon of the convention. Of the people on the panel here, everyone has done everything in placer mining, but we have tried to sectionalize it with each one of us taking a particular portion. Any one of us could probably answer any question. I am very pleased to see some well experienced people in the audience. To start the discussion, Joe, can you give us a brief comparison of pit and drill sampling? J. Wojcik They both have their place. If you expect your deposit is something that is going to have widespread fairly uniform grades, then the pits may be the way to go. If you are going to have something you have to trace for several miles down the river valley, you can't do it with pits and do a proper sampling job. C. McLain Joe, the end result of all of this is to go ahead and mine it if it is a deposit. Do you try to relate your drilling results to something in mining itself against the recovery, because the drilling in different types of ground will give you different kinds of recoveries, and mining in the end is what you are going to do? Do you try to relate this to your mining method?

Jan 1, 1992

By Fathi Habashi

WHILE HYDROGEN SULFIDE precipitates metal sulfides from aqueous solutions, other gases such as sulfur dioxide, carbon monoxide, and hydrogen, under certain conditions, precipitate the metals directly. This can be achieved at high temperature and pressure. Such processes are of great technical importance, since metals of high purity are precipitated economically in a powder form. As a result of the availability of such powders on a large scale. processes for compacting metal sheet and other mill forms directly from the

Jan 1, 1970

By A. Aubut, A. Proulx, O. Tavchandjian

Results obtained from conditional simulations and multiple indicator kriging were compared in the assessment of two different mining methods proposed for the extraction of the down-dip extension of a nickel-sulfide ore body located in the Thompson mining camp, Canada. An enhanced turning band simulation algorithm, supplemented with an unfolding technique, was used. A floating stope optimization process was used to effectively compare tonnage and grade figures. A calibration exercise was also conducted in the upper portion of the ore body. This study demonstrates that conditional simulations provide better spatial models for conceptual mine design and capital budgeting decisions.

Jan 1, 2004

By G. O. Kesse

The Republic of Ghana, located on the West Coast of Africa, is one of the West African countries rich in bauxite deposits. The main occurrences of bauxite deposits are at Sefwi Bekwai in the Western Region, Aya-Nyinahin in the Ashanti Region, Atewa Range near Kibi and at Mount Ejuanema both in the Eastern Region of Ghana. These bauxite deposits belong to the so-called blanket deposits as they are associated with erosion surfaces of old peneplains and occur as cappings on the flat tops of hills or mountains whose heights are generally greater than 600 metres above sea level. These deposits can also be classified as laterite-silicate bauxites since they have been formed under tropical weathering conditions. Genetic and mineralogical investigations have revealed that all bauxite deposits of Ghana are the result of indirect bauxitization processes, for the minerals of the weathering parent rocks have not been transformed directly into gibbsite. In all cases, lithomarge of kaolinitic clay can be recognised. The geology of the major occurrences of bauxite in Ghana shows that the Mount Ejuanema deposit is the only deposit associated with the Voltaian System of rocks. This rock System consists mainly of sandstone, shale, mudstone, conglomerates and pebbly beds. All the otter deposits are associated with the Birimian System of rocks which are made up of metamorphosed lavas,pyroclastic rocks, hypabyssal basic intrusives, phyllites, schists, tuffs and greywackes.

Jan 1, 1984

By Stefano Colombelli, Nicola Bona, Gabriele Eccher, Luca Schiavinato, Paolo Cucino, Domenico Nave

"BIM technologies provide tools and processes to effectively support the entire life of an infrastructure, from strategic planning to maintenance. As a consequence, infrastructure design processes currently make frequent use of BIM tools. This paper describes the BIM oriented design of the underground railway extension in the metropolitan area of Catania. The paper highlights the design process and the chosen BIM tools considering the boundary conditions characterizing the project, i.e. basic information missing in the final design project, need of coordination between different design disciplines and designer companies, and, finally, need for a flexible design approach able to adapt to changes occurring during design development. INTRODUCTION The underground railway extension in the metropolitan area of Catania is composed of two lots of approximately two km each, namely “Stesicoro-Aeroporto” and “Nesima –Misterbianco”. Works to be realized are: •,Main tunnel: mechanized tunneling using a TBM-EPB machine, for the entire length of the lot; •,Underground stations: San Domenico, Vittorio Emanuele and Palestro, conventionally excavated as enlargement of the TBM tunnel after the partial demolition of precast segments; •,Ventilation and emergency shafts: connecting seven tunnel levels to road level on Stesicoro-Areaposto lot, six on Nesima-Misterbianco lot; •,Additional structures such as technical rooms and parking lot; •,Electric Substation at Monte Po' stop; •,Temporary works: TBM launching and arrival pit to be dismantled at the end of the works."

Jan 1, 2016

By V. K. Kollipara

Dust dispersion characteristics in mine airways are important for developing engineering controls for dust and explosions. Authors here have used CFD modeling approach to analyze the dust dispersion characteristics in mine airways. The technique was initially validated with the published field experimental data. The results obtained were in a reasonable agreement. CFD validation results show that in a single entry the dust concentration decreases exponentially as a function of distance. Finer particles can travel up to a distance of 350-400 m away from the source. Parametric studies indicate that air velocity and input dust concentration has significant influence on dust concentration distribution. CFD modeling was then applied to study the dust dispersion characteristics in a room-and-pillar mine layout. Preliminary results show that dust concentration distribution is highly dependent on the airflow patterns and air velocity distribution. The distribution is not exponential until the velocity in the travel way becomes uniform. Data developed in this study may be used to design mine layouts and engineering controls for dust control and explosions.

Jan 1, 2011

By K. L. Browne

After a decade of high copper prices, major mining companies are renewing their interest in purchasing operating properties and/or developing ore bodies. An existing operation carries with it a history that can present unique opportunities, while a greenfield operation allows for the establishment of a defined culture. Capital investments are distinctly different. A comparison of BHP Copper's Robinson operation, a greenfield property, and BHP Copper's Tintaya operation, a government owned Peruvian property, will provide insights into mining, concentrating and cultural differences between North and South America operations. The Broken Hill Proprietary Co. Ltd. (BHP) is Australia's second-largest company. Fiscal year 1996 sales were US$16 billion, profits were more than US$1 billion and total market capitalization was about US25 billion. In 1885, BHP began mining silver, lead and zinc at Broken Hill, New South Wales, Australia. Throughout its 112-year history, BHP achieved an impressive record of performance and expansion. Today, BHP is one of the world's leading companies (66th on the Standard and Poors 500), having diversified into steel, petroleum and mining with more than 65,000 employees in 70 countries.

Jan 1, 1997

By Alan D. Hoagland

The Flat Gap Mine is on Copper Ridge in the Appalachian Valley of East Tennessee, Large zinc orebodies occupy zones of solution and collapse breccias in lower Ordovician Kingsport limestone and dolomite, The principal ore mineral is sphalerite and the principal gangue is dolomite, The orebearing horizons are considerably more than 95% covered by thick residual clay, and geochemical prospecting under these conditions is an effective exploration technique which played an important role in the discovery and exploration of the Flat Gap Mine, The residual nature of the over-burden at Flat Gap is emphasized, Background heavy metals (mainly zinc) range from 50 to 200 ppm, and the anomalies range to 3000 ppm and more, About 80% to 9W0 of the soil zinc is in relatively insoluble form in solid solution with the hydrous iron oxides and in the crystal lattice of the clay minerals. Quite discrete zones in the soil with sharply contrasting metal value boundaries mark vestiges of bedrock mineralization, and such anomalous soil areas are often contiguous with partially weathered ore. It has not been possible on the basis of chemical criteria to distinguish between an anomaly formed from non-commercial mineralization and one formed from ore.

Jan 1, 1962