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By Dennis Ofiara, Michael Lewis

An experimental 1.75 meter Shaft Boring Machine was designed and manufactured by The Robbins Company. The drill was used by contractor Drillcon Raise AB to drill test shafts at an SKB underground test facility. SKB is the Swedish authority responsible for safe management of nuclear waste materials. This “SBM1.8” Shaft Boring Machine was used to drill shallow test shafts ingranitic rock at SKB’s Aspo underground laboratory. The drill used a unique vacuum mucking system. The bored shafts were held to very strict tolerances for bore diameter, straightness, and verticality. This drill was launched and operated from a mobile launcher. Headroom and working space were limited. The SBM1.8 drill produced acceptable test holes. SKB will carry out several studies to determine the suitability of this geology, and of this technique, for safe nuclear disposal. In addition to future use at SKB, many applications are foreseen, particularly in the civil construction industry.

Jan 1, 2005

By William C. Grady

The environmental and economic problem created by pyrite in coal are well documented. The removal of pyritic sulfur prior to, or during, utilization has been the object of considerable research, however, much of this research has proceeded without a proper knowledge of the microscopic occurrences of pyrite in coal. This paper investigates the forms, occurrences, and variations in the distribution of pyrite in major West Virginia coal scan. Twenty-nine samples from twenty-two major west Virginia coal scans were selected for this study (see Table I). The samples were selected so as to be representative of the major coal producing areas of the state. All samples, except five, were collected at active surface mines, as indicated in Table I, and all except one were channel samples. The time interval between sampling and preparation of polished microblocks varied from two months to two years, though most were prepared within three months of collection. Grinding, screen¬ing, and riffling of samples to obtain 250 grams of -20 mesh coal for microscopic analysis strictly followed ASTM procedure D2013-72.

Jan 1, 1976

By D. R. Wilburn

The worldwide budget for non fuel mineral exploration was expected to increase by 27 percent in 2003 from the 2002 budget, according to the Metals Economics Group (MEG) of Halifax, Nova Scotia. The increase comes after five years of declining spending for mineral exploration. For the first time in several years, all regional exploration budget estimates for 2003 as defined by MEG would increase from similar 2002 estimates. However, MEG included 193 more companies in its 2003 survey than in 2002. As with previous MEG survey reports, estimates reflect anticipated expenditures rather than actual dollars spent. Caution, therefore, must be taken when comparing 2002 and2003 estimates or evaluating the magnitude of regional changes from year to year. Sample variations and currency exchange rates may influence year-to-year variations of MEG data. Even so, it is likely that the general climate of improved metal prices in 2003 encouraged companies that had previously left the mineral exploration sector or reduced their exploration activity to once again focus on minerals exploration or increase exploration activity and budgets.

Jan 1, 2004

By D. W. Tuckwiller

Electroplating is a widely utilized but little understood process. The fact that the average person is in contact with dozens of plated items daily without even being aware that they are electroplated is evidence of the success of the process. Although a complete explanation of electrodeposition involves thermodynamics and modern theories of bonding and catalytic reactions, in its simplest form the process conforms to the following description. A metal salt dissolved in water partially dissociates into negatively charged and positively charged ions. In the case of nickel sulfate dissolved in water, for example, a portion of the salt dissociates into positively charged nickel ions and negatively charged sulfate ions. If an electrical potential is applied between two electrodes in this solution, the nickel ions migrate toward the cathode and the sulfate ions toward the anode. The negatively charged cathode has a high concentration of electrons, which combine with the positively charged metal ions to form neutral metal atoms with a stable electron configuration. These insoluble atoms thus form a deposit on the cathode.

Jan 1, 1970

By William J. Maloney

OVERVIEW Blind drilled shafts are becoming increasingly popular, particularly in the Appalachian coalfields, as a secondary and sometimes primary means of ventilation. The reasons for the rebirth of the blind shaft are mainly due to it's economics, timeliness, safety characteristics and inherent independence from underground operations. Historically blind drilling has been used to a limited degree in hard rock and tunneling ventilation. With the recent advances in cutters, bit design, equipment and lining systems, particularly in the Appalachian coalfields, blind drilled shafts are once again the shaft construction technique of choice to the educated ventilation specialist. [ ] HISTORY OF BLIND DRILLING Blind drilling has it's roots in numerous places, including the Nevada Test site, the coalfields of Appalachia and Germany along with the uranium mines of Arizona. Early technology was developed using a variety of equipment mainly of oilfield origin with oilfield drillers entering the industry on a project basis only to "pull in their horns" and return to the oil patch. Shafts completed by oilfield equipment range from the shallow 5' and 6' lined shafts on the Nevada test site to two (2) 10' lined, 730' deep shafts in Alberta for heavy oil development. Several of these shafts were completed to extraordinary depths with the record being a 90" diameter, 6,150' deep shaft being completed in the Aleutian Islands of Alaska in 1969. EQUIPMENT Oilfield equipment is still being used on the Nevada test site but elsewhere specialized blind hole equipment has been developed to enhance the efficiency of particular applications. Where steel liners are required the A-leg derrick with a simple hoist and rotary system is used. The largest user of this type equipment in the world is the former USSR where blind drilling for mine ventilation is the norm. On applications where trip time and cutter changeout are a priority, top drive hydraulic rigs have been developed which are highly automated, efficient and mobile. These rigs are particularly well suited for tunneling applications where shafts are shallow and sites are usually tight.

Jan 1, 1993

By L. P. James, W. W. Atkinson

Utah has produced about one billion troy oz. (31.7M tonnes) of silver, more than any U.S. state except Idaho. Several very high grade ore systems, now closed, occur within large polymetallic limestone-hosted districts related to plutonic complexes. These Utah mines fed several major lead smelters for nearly a century. Interaction of magmatic chloride-rich fluids with carbonate rocks localized significant bonanzas within these districts. A low sulfidation state was produced in the fluids by their passage through limestones. The Bingham porphyry mine has also yielded more byproduct silver than other porphyry copper-gold systems. Away from exposed intrusive rocks, some large silver-only systems occur in Mesozoic sandstone and in caldera-related veins in volcano sedimentary rocks. Thick permeable latest-Proterozoic basement meta quartzite sequences present beneath western Utah may have been important, as perhaps they were in the Coeur d’Alene district of Idaho, in providing chloride and silver-rich ore fluids. However, it is clear that specific Tertiary magmatic events played an essential role in the evolution of the Utah silver-rich metallogenic province. The largest silver districts in the state are genetically related to porphyritic plutonic rocks.

Jan 1, 2000

By R. Parkins

This paper will discuss a method used to refine the fill level, and orifice size for a dual motor conveyor drive with extended delay chamber fluid couplings. The subject conveyor is located on the surface at the Mountain Coal Company West Elk Mine, located near Somerset, co.

Jan 1, 1996

By P. D. Chamberlain

Agglomeration for the heap leaching of gold and silver ores is the process of attaching fine ore particles-less than 150 µm (100 mesh)-to coarser particles. The fines are thus immobilized and uniformly distributed throughout the heap. This is needed to make heaps more porous and uniformly permeable to the flow of a leaching solution. This article describes liquids and binders used to form agglomerates. Agglomeration techniques and equipment are also described. These include drum and disk agglomerators, stockpile and belt agglomeration, and the use of vibrating deck and reverse-running conveyors. The need for agglomeration The main reason for agglomerating heap leachable ores is to prevent percolation problems in a heap. This is different than pelletizing iron ore. In the latter case, the purpose is to bond very finely ground material into coarser, strong particles. These particles can then withstand the rigors of transportation and the loading forces in a blast furnace. Most percolation problems in heaps are caused by the segregation of coarse and fine particles during heap construction. This segregation creates areas with significantly lower permeability because fines plug the channels between coarse particles. Consequently, the leach solutions are subject to channeling, following the path of least resistance. They percolate downward through the coarse ore areas and bypass or barely wet areas that contain large amounts of fines. This results in lower extraction, longer leach time, and higher reagent consumption. Permeability problems in heap leaching are compounded because of the vertical migration of fine particles after the heap has been built. These fines eventually accumulate in pockets or layers and impede uniform solution flow. The fines move because they are not attached to a coarser particle. Moreover, the sluicing action of leach solution flowing over the surface of particles may break the bond between fine and coarse particles. Some fines are also created by the decomposition of ores after being wetted. Percolation problems are minimized if the fines can be attached to the coarser particles. Fines are thus uniformly distributed and rendered immobile within the heap. Heinen (1979) conducted comparative tests of nonagglomerated and agglomerated gold and silver ores. He showed that percolation rates through agglomerated material usually are improved by 10 to 100 times. This reduces leach time for economic recovery to less than one-third of that for nonagglomerated material, and total recovery may be increased. Cyanide consumption is also reduced in most cases because of the shortened leach time. Even run of mine (ROM) ore should be agglomerated. This can be achieved with moderate success by passing each truckload of ore under a water spray to bring total moisture of the ore up to about 8% to 10%. The ROM ore will mix when the ore is dumped, when it cascades down the slope of a heap, or when it is pushed up with a dozer. Overall, agglomeration allows low-cost heap leaching technology be applied to gold and silver ores and tailings that could not be economically processed by conventional methods, according to Phariss (1982). How agglomeration works Agglomeration means that the clays and fine particles contained in the ore adhere to the coarser particles. This creates a coating of fines around the coarse particles. When the ore has few fines and the percolation problems are not severe, the addition of a liquid may be all that is necessary to make the few fines adhere to coarser particles. However, when the quantity of fines is substantial, e.g., +10% -75 µm (-200 mesh), a binding agent may be needed. Use of solution only for agglomeration There are many forces that cause agglomeration and one of them is the surface tension of water. Water-saturated particles collide with each other or with

Jan 12, 1986

By Song Xiaotian

Studies have been carried out to optimize the VCR's mining sys- tem on the basis of synthetic analysis at Fankou Pb-Zn mine in Southern China. The synthetic e- valuation method is proposed for selection of mining alternatives and stope dimension optimization techniques. Theoretic calculation and computer optimization of the fragmentation of rock blasted by multispherical explosive charges are discussed. The mathematical and optimal fragmentation models are built. The optimum model is built for the main mining operations such as drilling, blasting and haulage. Lt can be used to evaluate VCR?s mining projects, select mining parameters and provide design fundations. From the point of view of system research on the geomechanical process, stoping technological process and benefit, the complex method of optimization is proposed for VCR's mining. Using computer simulation, based on this model, the optimal parameters are established and analysed. An effective approach is provided for research on the mining method optimization and getting better economical benefits from the application and improvement of VCR's method.

Jan 1, 1986

By H. Schultheis

The European Commission has launched in April 2002 the Thematic Network NESMI with-in the FP5 under Growth. NESMI stands for ?Network on European Sustainable Mining and Processing Industries? and will run until 2005. Within NESMI there are different ways to set up indicators and evaluate them throughout the NESMI Members. First analyses concerning the Demand and Competence within NESMI are developed. New focus points for analyses can be implemented into NESMI.

Jan 1, 2003

By Stephen H. Stow

Economically important heavy minerals have been studied in the sediments of offshore Alabama and Mississippi. Sandy samples have been collected from a 200 square mile area from Dauphin to Horn Islands. The minerals concentrate in sediments under 10-35 feet of water and may reach 2.4% by weight. The distribution of total heavies is related to the hydrodynamics of offshore Alabama-Mississippi; the greatest concentrations are in the Gulf where the longshore current is diverted from its westerly flow. Preliminary observations indicate that the distribution of individual minerals can be correlated with wave energy, particle size, specific gravity, and morphology of the mineral grains. The coarser, lighter minerals--kyanite, sillimanite and staurolite--are concentrated in relatively low energy areas in the Mississippi Sound and at the end of Dauphin Island in the Gulf; maximum concentration for each is 34.5%, 6.0% and 43.2%, respectively, of the heavy minerals. The smaller, more denseminerals--ilmenite, rutile, leucoxene, zircon and monazite--are concentrated in high energy areas in the Gulf; maximum concentration for each, respectively, is 42.0%, 5.9%, 9.652, 10.7% and 1.3% of the heavy minerals. On the basis of a minimum concentration of 1% heavy minerals, two areas have been identified and the total amounts of different minerals have been calculated to a depth of 25 feet of sediment. The data are preliminary and in no way indicate recoverable reserves, but they do show that on the order of 20 million tons of heavies exist. These deposits should be termed "indicated resources".

Jan 1, 1975

By M. A. Trevits, G. L. Finfinger

Various methods have been developed through US Bureau of Mines research to remove gas in advance of, during, and subsequent to mining. These include drilling horizontal or cross-measure boreholes from a mine opening, and vertical boreholes stimulated for drainage in advance of mining or for gob gas drainage. Techniques and equipment now exist that allow drilling a borehole at any angle to the vertical, and even along an arc. Stimulation treatments have also been developed that provide for increased gas production capability. This paper describes the long-term production history of five select gas drainage installations. The Bureau of Mines conducted or participated in four studies. The remaining study was conducted by the Equitable Gas Co. Principles of storage, release, and migration of coal bed gases The amount of gas contained within any given area of a coalbed depends on the coal's inherent storage capacity and the physical conditions of the coalbed. The gas storage capacity of coal is primarily a function of rank. As such, it cannot be affected by the presence of drainage holes (Kim, 1977). Certain physical conditions of the coalbed can, however, be changed that will affect the release and migration of gas. By pumping water out of the coalbed through the vertical boreholes, two important changes occur - pressure is reduced and water saturation is lowered. Reducing reservoir pressure releases gas as the coalbed adjusts and equilibrates gas to the change. Increasingly large amounts of gas are released for each incremental decrease in pressure. Lowering the water saturation level raises the permeability of the coalbed to gas and allows the gas to more readily migrate to the wellbore (Kisse and Edwards, 1975). For horizontal boreholes completed near mine openings, the coalbed has already undergone a pressure or water saturation reduction phase. This condition thus allows such boreholes to be highly productive with minimal water production. Case studies of coalbed gas production Pittsburgh Coalbed - Marianna mine 58 A methane drainage study was begun in July 1978 at Bethlehem Mines Corp.'s Marianna mine 58, Marianna, PA (Fig. 1). The work was conducted in a section of the mine that was advanced 1.5 km

Jan 8, 1986

By J. M. Barker

New Mexico is the leading domestic producer of perlite, a hydrated volcanic glass that can be expanded thermally to form a white, very porous, lightweight material. The United States is the leading consumer and producer of perlite in the world (Pettifer 1981). New Mexico produced, at five mines (Fig. 1), about 86% of all domestic crude ore mined in 1984 (Meisinger, 1985). Perlite is mined in 6 other western states, ore is expanded in 33 states, and the expanded ore is consumed in all states (Meisinger, 1985). Gross value of domestic ore mined in 1984 was about $16,500,000 (FOB mine; Meisinger, 1985) with much value added by expansion and processing prior to sale to end users. In contrast to the ubiquitous nature of perlite products in the U.S. economy, facilities for testing perlite ore, expanded perlite, and perlite products are notably lacking on a commercial, cost-effective, or readily accessible basis. The New Mexico Bureau of Mines and Min¬eral Resources (NMBM&MR) established a perlite¬testing facility in 1984 to mitigate this lack and to further the mining of perlite in the state.

Jan 1, 1985

By W. Dan Hausel

Archean supracrustal rocks of the South Pass greenstone belt of western Wyoming have been an important source of gold and iron ore. Actual gold production statistics are incom- plete although gold production estimates for the South Pass- Atlantic City district range from a low of 2.0 Mg (70,000 oz) (Koschmann and Bergendal, 1968) to a high of 9.8 Mg (327,000 oz) (Hausel, 1980). From 1962 to 1983 iron ore was also mined from the greenstone belt and production totaled more than 91 Mt (90 million It). The supracrustal rocks of the South Pass greenstone belt occur in a tightly folded synform bounded by Late Archean granite and granodiorite. The youngest of the Archean successions has a reported Rb-Sr isochron age of 2.8 b.y. (Stuckess, et al., 1985). Metamorphism of the supracrustals increases towards the flanks of the belt and is amphibolite-grade enclosing a small island of greenschist facies rocks. The supracrustal sequence consists of metasedimentary and metaigneous rocks that are divisible into four mappable units. The metasediments include metagraywacke, quartzite, pelitic schist, banded iron formation, metaconglomerate, and graphitic schist. Metavolcanics include metabasalt, meta-andesite, and ultramafic schist. These supracrustals have been intruded by mafic sills and dikes and tonalitic stocks and dikes. Two granite plutons and associated pegmatites intrude the supracrustals in the western portion of the belt, and the supracrustals exhibit both fault and intrusive contacts with granitic batholiths along the western and eastern margins. The northeastern flank of the Archean belt is unconformably over- lain by Paleozoic sediments, and the southern portion of the belt is onlaped by Tertiary sediments.

Jan 1, 1990

By A. R. Garcia, A. S. Myerson, W. R. Ernst, J. D. Carruthers, M. D. Franke, L. H. Hilzik

A method for removing nickel and vanadium contaminants from spent HDS catalysts involves pretreating the catalyst with H2S followed by extracting the metals with an acidic solution of ferric ion. The ferric ion solution alone removes significant amounts of active ingredients, cobalt and molybdenum; however, by pretreating with H2S, the extraction becomes more selective for removal of Ni and V.

Jan 1, 1988

By R. R. Klimpel

During the period of 1973-79, an extensive period of research and development was undertaken by Klimpel and coworkers (1980, 1981, 1982a, 1982b, 1983. 1984, 1987) on the identification of a commercially viable chemically assisted approach to improving the efficiency of the wet grinding of coals and ores in tumbling media mills. The emphasis of the previous publications just listed was on the engineering use implications of controlling-slurry viscosity (rheology) in laboratory and plant scale grinding devices. In this paper, some discussion and results pertaining to the actual chemical screening phase will be presented.

Jan 1, 1988

By F. G. Miller

To improve coal flotation Bethlehem Steel Corporation's Research Department has been working on a number of related problems based on both physical and chemical factors. The ideal is of course full understanding of the interrelated effects of both sets of factors. However, detailed studies5 of each physical factor have produced immediately usable results in commercial coal flotation and are providing the bas is for our current work on the effect of chemical factors. Since these detailed studies provided the basis for the present investigation of froth sprinkling, their key results are highlighted here. For example, for a highly floatable bituminous coal, particle floatability was shown to be directly related to the percentage of coal surface available for bubble attachment and inversely related to particle mass. The data also underscored that in a given size range the addition of mineral matter to a particle makes flotation more difficult both by adding to the mass of the particle and by decreasing the amount of coal surface available for bubble attachment. Size also affects particle floatability in that as the size of particles of a given specific gravity increases, mass increases and the ratio between coal surface area and mass of the particle decreases. Flotation tests showed that any recovery of the coarsest particles in a coal feed is accompanied by progressively higher recovery of finer and finer particles. Consequently, fine high-specific-gravity particles are recovered with the coarse good coal. As a result, when the entire 14M x 0 size range is processed by froth flotation, the good coarse coal is contaminated with high-specific-gravity fines. It is the small quantities of these fines that must be rejected from the froth product if flotation efficiency is to be increased above its present level.

Jan 1, 1968

By Clyde L. Smith

Since the early 1950's exploration in the Yukon Territory, Canada, has been confined largely to Selwyn basin where at least five large stratiform or massive sulfide Pb-Zn deposits have been discovered. The five ore bodies total nearly 100 million tons of 10-16% combined Pb-Zn with 1-3 oz./ton Ag. The only deposit currently in production is the Anvil Mine operating at 8,000 tons per day. Beginning in 1972, exploration in the Mackenzie Mountains, east of Selwyn basin and west of Mackenzie arch, resulted in finds of Mississippi Valley type Zn-Pb mineralization in a belt of Proterozoic and Lower Paleozoic carbonate rocks (Figure 1). Four districts have been located and intensive exploration by numerous Canadian and Arnerican mining companies is currently in progress over a length of 400 miles in the carbonate belt. The consensus is that a major new Zn-Pb province may be taking shape.

Jan 1, 1974

By H. Murray

Introduction Industrial minerals are key ingredients in a large majority of domestic and industrial products that are used in our daily lives. In the 7th edition of Industrial Minerals and Rocks, fifty three industrial mineral commodities are described. A precise definition of industrial minerals and rocks is difficult. Bates (1975) proposed a definition which is widely used and is as follows: "any rock, mineral, or other naturally occurring substance of economic value, exclusive of metal ores, mineral fuels, and gemstones: one of the non-metallics". They can be igneous, metamorphic, or sedimentary and range in price from a few dollars per ton to a very high price of hundreds of dollars per ton. The growth in their production and use is closely allied with population growth particularly in countries that maintain a high standard of living. The United States just passed 300 million in population and it is predicted that by 2040 the population will be 400 million. This will result in large increases in the need for Industrial minerals. Other factors that relate to increased use of industrial minerals are increased research and development by the producing companies and better quality control. Many industrial minerals such as kaolin, barite, nepheline syenite, fluorspar, lithium carbonate, phosphate rock, potash, talc, and several others are exported from the producing countries to many users around the world which has significantly increased their use. Also, government agencies, State Geological Surveys, and Universities have contributed to their growth by their research and development activities.

Jan 1, 2007

By Stephen P. Mulqueen

Searles Lake is an evaporite basin located near the community of Trona in northwestern San Bernardino County, CA. Searles Valley Minerals Operations Inc. (SVM), a subsidiary of Nirma Limited, currently manufactures more than 1.58 Mt/a (1.75 million stpy) of industrial minerals from natural brines produced from several lakebeds within the basin. The chemical manufacturing facilities in Searles Valley represent extremely complex operations involving solution mining and mineral extraction processes.

Jan 1, 2012