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By James A. Madonna

Several universities and colleges in Australia, Canada and the United States, recognized the need to establish or reorganize geoscience programs at the vocational and two-year technical levels. To accomplish this, a cooperative study with industry in one state or province from each country was initiated. These include Tasmania in Australia, British Columbia in Canada and Alaska in the United States. The objective of this work was to develop a diversified geoscience educational model at the two-year technical, vocational and continuing education level that provides the source from which any nation can draw the proper educational tools to create a new geoscience program, modernize an existing program or strengthen a weak program. More than 100 mineral industry organizations provided information regarding their specific training needs for support personnel. The data gathered have been used to identify training areas for semi-skilled, skilled and technical personnel in geochemical mineral exploration. These included geological, geochemical, environmental and computer skills. With the areas of major educational need defined for geochemical exploration, an educational field skills model was developed for the three levels of training. The international need for a study of this type was recognized as early as 1980, following numerous contacts from domestic and foreign geoscience educators regarding the structure and success of training within the University of Alaska Fairbanks Mining Extension program, located in Fairbanks. Contacts, correspondence and visits included educators from Australia, Brazil, Canada, Mozambique and the conterminous United States. The need was magnified between 1985 and 1989 at the University of Alaska Fairbanks, when an attempt failed at initiating and developing a two-year geoscience vocational-technology program leading to an Associate of Science degree.

Jan 1, 1994

By George Wilson

When pumping abrasive slurry mixtures, special attention must be given to pump design and construction. The second article in this two-part series describes some design features to consider when selecting centrifugal slurry pumps. Hydraulic Design Most centrifugal pumps are conventionally designed to achieve the desired hydraulic performance at the highest efficiency and lowest cost when handling clear fluids in reasonably clean environments. Manufacturing limitations are not imposed on the configuration of the pump, since conventional materials such as cast iron, bronze, and stainless steel are used. Manufacturers and buyers usually select the highest specific speed commensurate with the lowest cost attainable. Part life is almost infinite. When a centrifugal pump is designed for slurry service, the important factors in pump design are wear and materials of construction; size and efficiency assume lesser importance. The pump must operate at low rotational speed and the impeller has to be a truly radial flow design. These factors immediately determine that the pump must be of a low specific speed design in the range of 600 to 1800. The specific speed is a type number that is constant for all geometrically similar pumps; it designates the geometry of the impeller and casing. [ ] where n = rpm, Q = flow (US gpm), H = total head (ft), and Ns = specific speed. Since wear is a function of velocity it can be shown that for a given head and capacity, wear will increase with increased Ns. Centrifugal Pump Casing The casing has a profound effect on performance. If designed incorrectly it can destroy a large part of the energy given to the flow by the impeller, resulting in low efficiency, high hydraulic forces, and excessive wear on both the casing and impeller. In a conventional spiral volute, the static pressure around the impeller is uniform only when there is a free vortex velocity distribution in the volute, i.e., when the spiral flow from the impeller coincides with that of the volute spiral. This occurs only at the best efficiency point (BEP), between the pump's best operating zone and over capacity zone. Departure from the free vortex velocity distribution in the volute at partial or over capacities produces circumferential pressure gradients at the impeller periphery, which is directly proportional to the specific gravity of the mixture being pumped. At partial or over capacities, the flow will not tolerate the abrupt deflection at the tongue and severe energy losses and wear are created near the casing throat and on the impeller. Concentric and semi-concentric volute designs produce uniform static pressures at the impeller periphery and make the pump, much less sensitive to "off"' BEP operation. Hydraulic forces and wear are considerably reduced-eliminating the tongue prevents abrupt deflection of the flow, turbulence is minimized, and the velocity in the casing volute and throat is reduced. Good efficiency is sustained over a wider operating hand. Casings of this design are easy to cast. • Spiral volute (conventional)-Radius to the outer periphery of the casing and the volute area constantly increases. • Semi-concentric casing-Radius to the outer periphery of the casing and volute area remain constant within a certain angle. • Concentric casing-Radius to the outer periphery of the casing and volute area remain constant through 360°. The degree of concentricity must be reconciled with efficiency, hydraulic radial load, and wear for each specific speed chosen. Up to 1200 Ns the casings can be fully concentric without sacrificing too much efficiency. Above 1200 Ns, the casings can be semi-concentric. The angle of concentricity

Jan 10, 1981

By William R. Yernberg

The Cripple Creek & Victor Gold Mining Co.(CC&V) celebrated completion of a two-year, $168.5-million expansion and capital improvement program. An open house celebration was held in the historic mining town of Victor, CO on Oct. 4, 2002. Hundreds of townspeople, the press and other invited guests from the mining industry joined the employees of CC&V in the celebration. The event included mine tours, company displays and a barbecue picnic, complete with a country and western band. The Cresson Mine is located about 40 km (25miles) west of Colorado Springs, CO between the towns of Cripple Creek and Victor. The mine is the only large-scale gold mining operation in Colorado and now employs about 300 (ME, October 2001, pp.21-28). The operation is a joint venture between Anglo-Gold (Colorado) (67%), based in Greenwood Village, CO, and Golden Cycle Gold (33%), based in Colorado Springs. CC&V is managed by AngloGold North America. AngloGold North America is the U.S. subsidiary of AngloGold, the world’s second largest gold mining producer. AngloGold is based in Johannesburg, South Africa.

Jan 1, 2002

By P. M. Prasad

Off-grade molybdenite concentrates, mainly derived from secondary sources as by-products of the processing of copper, uranium and tungsten ores, do not satisfy the purity requirements (percent MoS2) for the production of molybdenum bearing products. This investigation is a continuation of a successful effort to refine a low-grade molybdenite concentrate to prepare a high-grade MoS2 using a mixed acid (HF + HCl) leach procedure. Specifically, this investigation is concerned with an understanding of the separation chemistry underlying the removal of the oxide/silicate gangue and the base-metal sulfide associations present in the low-grade molybdenite by their selective dissolution in the two acids. Experiments were conducted on an off-grade concentrate containing 42.6% Mo. Results of the controlled dissolution tests indicate that both HCl and HF are suitable for the removal of the associated alumina and both work well for iron, nickel and copper. However, HF was found to be the most effective for dissolving silica/silicate and magnesia. An attempt was made to rank the leaching efficiencies of the acids used singly, sequentially or in a mixed mode. Scale-up (300 to 2,000 g) experiments were conducted to validate this approach. Excellent purification of the concentrate was possible by processing the off-grade concentrate with 10% HCl plus 15% HF at 363 K for 7.2 ks in open polypropylene reactors with internal stirring. These conditions leached practically all of the oxide and silicate gangue and 96% of the metallic impurities. Starting from the low-grade molybdenite concentrate (42.6% Mo; 71.1% MoS2) it was found feasible to obtain a refined product containing 97.8% MoS2, which is suitable for industrial use.

Jan 1, 2007

By H. C. Liang

Reverse osmosis (RO) and nanofiltration (NF) are widely regarded as being best available technologies (BATs) for removing contaminants of concern from water. In recent years, NF or RO treatment has increasingly gained more acceptance in the mining industry for treating mine water to remove a wide assortment of contaminants, either for meeting discharge standards or for internal re-use in mining processes. Consequently, the number of NF or RO membrane mine water treatment facilities has steadily increased. Although NF or RO membrane filtration can be a powerful tool in mine water treatment, especially when multiple contaminant removal is required, it also has many potential disadvantages. Besides the generally higher capital and operational costs for the high pressure membrane processes, organic constituents in mine water may foul the membranes, while inorganic compounds such as gypsum, calcite, or silica are liable to scale the expensive membranes if proper pre-treatment processes are not implemented. Additionally, because these membrane treatment processes generate a substantial reject or brine waste stream in addition to the clean treated water or permeate stream, brine management also needs to be considered carefully when deciding upon the viability of an NF or RO mine water treatment process. Because of these issues, it is important to conduct detailed analyses of the trade-off between selecting NF or RO vs. using chemical treatment processes when designing a mine water treatment facility.

Jan 1, 2012

By M. Perolo, A. Contini, E. Ramelli, G. Borgonovo, L. Locatelli

This paper presents the ground settlement monitoring system used during the construction of two tunnels bored by two EPB TBMs, beneath the existing and active railway embankment in Bologna (Italy). The tunnels run close to large buildings and beneath bridges and other infrastructure. Data are collected from remote total stations and from electro levels installed directly on the railway tracks. The automated monitoring system acquires and analyses data then sounds an alarm in the event that there is a problem. Alarms are sent out in case of excessive tilt or settlement. Data is provided through a dedicated web application for multiple-party access, to gather, manage and store monitoring data.

Jan 1, 2007

By Lane White

Refractory gold ores are those from which a significant percentage of the gold cannot be recovered by conventional cyanidation. Historically, roasting has been the primary method for rendering such ores amenable to gold extraction; however, roasting creates environmental problems that are not acceptable in many locations. During the 1980s, consistently strong gold prices drew increasing attention to refractory gold ores, and new processing schemes were commercialized, most prominently aqueous pressure oxidation and more recently bacterial oxidation. Since 1985, pressure oxidation has been incorporated into four plants processing refractory gold ores. A fifth plant is scheduled for start-up in early 1990, and three additional plants are scheduled for production before late 1992. A technical session on treatment of refractory ores was included in the program of `World Gold '89, a Gold Forum on Technology and Practices' held by SME and the AusIMM in Reno, NV, Nov. 5-8, 1989. This article summarizes material from five of the papers presented during the refractory gold session and published in the proceedings of `World Gold '89,' edited by Roshan Bhappu and Rod Harden. The complete proceedings are available from SME Publications Sales, P.O. Box 625002, Littleton, CO 80162-5002 $53.50 for members, $38.50 for student members, and $73.50 list price.

Jan 1, 1990

By A. Founie

The United States continues to be the world’s leading producer and consumer of diatomite. Production of diatomite in the United States during 2004 was estimated to be 635 kt (700,000 st). This was a 2-percent increase from 2003. The value of processed diatomite in the U.S. was about $164 million in 2004. Production was from six companies with 13 processing facilities in four states. Nevada and California were the principal producing states. They accounted for about78 percent of the U.S. production during 2004. U.S. diatomite exports were about 136 kt (150,000 st). Imports were negligible.

Jan 1, 2005

By B. J. Schat, A. W. O. Bots, O. S. Langhorst

Amsterdam City Council is building a new metro line, the North–South Line. The line passes under Amsterdam Central Station (a listed building) about 18m below street level. The retaining wall that has to be built underneath the existing building is an innovative construction consisting of two rows of steel piles interspersed with a solid mass of overlapping jet grout columns: a composite ‘sandwich’ wall. This paper gives an overview of the approach taken to designing (computational models) and building the retaining wall. Special attention is paid to the observational method used for the construction of the jet grout columns.

Jan 1, 2007

By L Baumgardner, A. V. Castelli

Barite In 1987, United States mine production of barite increased 15.870, consumption (sold or used by grinding plants) increased by 6.97, and imports are estimated to have fallen by 19.57. World mine production decreased by 137, according to the US Bureau of Mines. The value of US produced barite, fob mine, decreased 1.4%, according to the Bureau. The declared value for cif US port of all imported unground barite during the first 10 months of 1987 decreased from $39.02/t ($35.40 per st) to $37.16/t ($33.71 per st), the Bureau stated. Nevada continued to be the leading US producer of' barite with 637r of the total. It is followed by Georgia, Missouri, California, Tennessee, and Montana. The Bureau of Mines estimates 657 of the US mine production was used as a weighting agent in drilling fluids. The remaining 35°/r was used in barium chemicals, glass or as a filler. Most of the production from Missouri, Georgia, and Tennessee was used in the non-oilfield sector. This sector continued to increase. Of the total consumption (used by grinding plants and chemical manufacturers), it is estimated that 8070 was used in drilling fluids and 2017( in the non-oilfield sector - barium chemicals and fillers in paper, plastics, and glass. The tonnage consumed in the drilling fluids market increased slightly. But the average number of rotary rigs operating decreased from 964 in 1986 to 936 in 1987. This is the lowest number of operating rigs reported since 1949. The increase in consumption in this sector is due to an increase of rigs operating in the US Gulf and other higher consumption areas over 1986. Crude barite imports were estimated to be down by 19.5% in 1987. Still, they accounted for 637 of the barite consumed in the US. During the first 10 months, China continued to be the leading exporter to the US with 86.970, followed by Mexico with 10.997, and Morocco 2.107(. About 5Y of the imported ore was used in the nonoilfield sector. Ground barite imports dropped from 19.8 kt to 8.8 kt (21,800 st to 9800 st) in 1987. Of this amount, 1.4 kt (1598 st) was used in drilling muds and the remainder of the non-oilfield use. During 1987, a few more grinding plants that supplied the drilling fluid market were closed. Along the US Gulf Coast, there are 13 operating plants versus a high of 31 in 1981. Cameron Offshore reopened its grinding plant at Cameron, LA. New Riverside Ochre Co. of Cartersville, GA, purchased a jigging-washing plant in Missouri and plans to place it in operation this year on a new deposit near Cartersville, GA. Milpark purchased Hughes Drilling Fluid in 1987 and operates under Milpark. US mine production will probably stay about the same as 1987. Price increases in the 10 % range for imported ore are expected due to water freight and the weak dollar. Baker Hughes estimates the average number of operating rotary rigs at 1070. A slight increase is expected in the non-drilling fluid market (chemicals, glass, and filler). Bauxite and alumina L. Baumgardner, US Bureau of Mines Domestic bauxite production in 1987, expressed as dried equivalent, was 581 kt (640,400 st), a 14% increase over 1986. US mine production amounted to less than 170 of total world production. Virtually none of the domestic bauxite was consumed in the production of primary alumina metal. About 30% of the bauxite produced by US mines was calcined to produce 117 kt (128,970 st) for use in abrasives, catalysts, chemicals, proppants, and refractories. Most of the uncalcined bauxite was refined to specialty aluminum oxide (alumina) forms. Metallurgical grade bauxite was imported from 10 countries in 1987. Principal suppliers of the 9.8 Mt (10.8 million st) were Guinea (4270), Jamaica (3501,), Australia (127), and Brazil (57). The average value, delivered U.S. ports, cif, as reported to US Customs Service, was $29.50/t ($26.76 per st). Calcined refractory grade baux-

Jan 6, 1988

MINExpo International is billed as the largest exposition for the mining and mineral processing industry. And the 2012 edition, scheduled for Sept. 24-26 in Las Vegas, NV, is no exception. Put on by the National Mining Association (NMA), attendance at this year?s show is expected to be significantly more than the 38,500 who attended the last MINExpo in 2008. The exhibit will also be quite a bit larger in 2012 than it was at the previous MINExpo. More than 1,800 companies, representing more than 30 countries, will fill the Las Vegas Convention Center. The more than 850,000 sq ft of exhibit space will include the North and Central halls as well as South Halls Nos. 3 and 4. And the Silver Lot outside of the front door, under construction in 2008, will be filled with more exhibitors. The 2008 show attracted about 1,220 exhibitors occupying more than 600,000 sq ft of exhibit space.

Jan 1, 2012

By I. Ocak

Initial investment for mechanical boring of tunnels is found to be high in most cases. Conventional drilling and blasting is not the possible especially in urban area. In these conditions impact hammer offers many advantages over conventional drill and blast techniques and boring tunnels. These include improved safety, minimal ground disturbances, elimination of blast vibration, reduced ventilation requirements, reduced cost etc. Therefore, hydraulic impact hammers have been used widely in metro tunnelling projects in Istanbul since 1992. Accumulated and published data from various tunnelling projects serve to improve predicting the machine performance and scheduling of job duration. This paper is prepared under this objective. Machine utilization time of impact hammer was evaluated in this study. The main rock formation named Kartal formation arepaleozoic aged sedimentary rocks, shale, sandstone, siltstone, andesite dykes and sediment fillings. The first stage of the project is commissioned to Yapi Merkezi- Yuksel- Dogus- Yenigun- Belen consortium.

Jan 1, 2011

By B. C. Vargas

The Toulon tunnel project is a key component of the Highway corridor on the French Riviera between Marseille and Nice and is a fundamental transportation infrastructure for the region. The first design studies started in the 1960?s. The tunnel project is made of 2 separate tunnels: South and North tunnel. The North tunnel was built between 1992 and 2002 after 10 years of difficult construction (for example, on March 15th, 1996, a collapse of the tunnel in the ?Marchand Area? generated a sink hole in the city Center, causing 20 months delay). The South tunnel alignment runs parallel to the North tunnel at the same depth below Toulon historical downtown (20 to 40m depth with some areas with less than 10m of cover). The Risk management program was studied to be a State of the Art program in urban tunneling construction. The Hydro Geological Context The whole project area is covered with backfills and colluviums of 1 to 4m thick. The Schist, marls and sandstones, randomly distributed along the alignment below the first layer have different characteristics. While the Schist are pretty compact, the marls are fractured. The other layers have very different characteristics, and many faults are located along the alignment, especially in the limestones. The Breccia are heavily decompressed and deformable, as well as the other soils located in the Marchand Area. This 80m long area is where the settlements need to be controlled with an extensive monitoring program. The complete Geological profile is presented in Figure 1. [ ]

Jan 1, 2012

By T. Weatherwax

As part of a strategic research initiative at UBC to design and evaluate integrated underground mining and mineral processing systems, work has been done to determine how to utilize the coarse rejects of pre-concentration in the underground environment. An amenability study for nine orebodies from four of Xstrata Nickel?s Ontario operations evaluated both processing and waste disposal methods. The utilization of the rejects as a high quality backfill with minimal binder requirements has been identified as the preferred disposal method. Fill mixes utilizing the rejects in combination with classified tailings, full tailings, and cement were developed based on the geotechnical properties of the rejects. The mix designs were examined for both strength and rheological properties. The paper will present the results of the pre-concentration testwork, the design and strength testing of various mix designs for rejects from the nine ores and presents a conceptual design for an underground pre-concentration system based on this test work.

Jan 1, 2008

By Chester M. F. Peters

INTRODUCTION There has been considerable discussion in recent years of the strained relations between owners, engineers and contractors caused by the rapid increase in costly litigation in underground excavation due to construction claims. These time consuming claims are not to the best interests of the industry. It has been a conclusion of some of the concerned parties that there could be a substantial reduction in these claims if a mutual respect for each other's roles could be maintained along with a practical contractual arrangement for sharing the risks of the unforeseen costs inherent in the business. This paper will touch on the overall problem of these relationships, but confine the major discussion to the role of geology in claims and, in particular, changed conditions claims, since they form the base for the bulk of those involving geology. Geologists can make a major contribution to the reduction of these claims if their particular abilities are recognized and used properly. CLAIMS AND GEOLOGICAL RISKS The tunnel contractor is strictly bound by the contract he signs, and the risks he assumes thereby must be priced. The most important variable factor on which he must base his price is the geologic data provided and his interpretation of it. If this data does not give a clear picture of the conditions, making it impossible to price

Jan 1, 1974

By Jafar Khademi Hamidi

The Zagros long tunnel is one of the main components of Sirvan water transfer project in western Iran. It is approximately 48 km in length and consisted of two lots. The second 26 km lot of this tunnel is under construction by a 6.73 m diameter double shield (DS) TBM. The tunnel passes through several formations with wide range rock mass qualities. During the tunnel alignment, changes in rock quality were highly frequent from poor to very good. The encountered geological conditions required TBM operation to change frequently from hard rock to soft, dry to flowing, sticky to nonsticky ground (and vice versa), more often than expected. In the course of tunneling, the machine has encountered nearly many adverse geologic conditions. The most important problems have been sudden high volume water inflow into the tunnel, sticky ground, and gas seepage, all of which resulted in reduced TBM advance rates. This study will high-light two difficult ground conditions including large water ingress and sticky ground and also the related problems encountered by the TBM along 8 km of excavated tunnel. In sticky grounds, cleaning of the clogged cutter head caused many delays and contributed to additional downtime. Application of some operational modifications, including decreased TBM thrust showed satisfactory results in such cases. While reduced thrust resulted in reduced penetration rate, but the overall TBM advance was greatly improved by the increase utilization rate and elimination of down time related to cleaning of the head. To cope with high water inflow, application of preventive measures such as pre-grouting has proved to be a more efficientsolution. The sealing of ground water inflow also decreased seepage of dangerous H2S gas and other chemicals such as hydrocarbons accompanying the groundwater.

By A. Ramage

Since late 2010, CH2M HILL has been working with a confidential client who holds a long-term commitment to sustainable development (SD). The commitment is aligned with all three elements of the triple bottom line: people and society, ecosystems and environment, and financial and economic systems. These commitments are carried forward by the firm?s executives, managers, and operational sites, and are evident in materials posted on the company?s public website. These materials include a formal sustainability report prepared in accordance with the Global Reporting Initiative (GRI) guidelines (GRI, 2006), a report that outlines key SD challenges and progress toward the GRI targets, and a delineation of risks and opportunities outlined in the firm?s Form 10-K and Annual Report. In keeping with its commitments to SD targets, our client wished to consider SD issues in its decision processes for facility expansion or new projects. The company engaged CH2M HILL to meet this goal, based on working relationships established through existing contracts and CH2M HILL?s leading capabilities in sustainable solutions.

Jan 1, 2012

By B. Anameric, S. Kawatra

Pig iron nuggets, which have similar chemical and physical properties with blast furnace pig iron, were produced by a single step heat treatment of self reducing – fluxing dried greenballs. During this single step heat treatment the transformation of self reducing fluxing dried greenballs into pig iron nuggets did not take place instantaneously. Rather, it was composed of three transformation stages, (1) transformation of self reducing – fluxing dried greenballs into direct reduced iron (DRI), (2) transformation of DRI into transition direct reduced iron (TDRI), and (3) transformation of TDRI into pig iron nuggets. Thus, the objective of this research was to investigate these transformation mechanisms by analyzing the transformation stage products. The transformation stage products were produced at a constant furnace temperature of 1425°C and various furnace residence times. They were characterized according to their microstructure, microhardness and apparent density. The changes in the product’s physical and chemical properties with furnace residence time were utilized in understanding the transformation behavior, the chemical events that took place and the controlling mechanisms. It was determined that the transformations were dictated by the changes in the slag viscosity and wetting properties, and by carbon diffusion into metallized areas.

Jan 1, 2007

By J. O. Marsden

Parts I and II in this series of papers presented the chemistry of medium-temperature pressure leaching of copper sulfide concentrates and reviewed the metallurgical development of a process to effectively recover copper using medium-temperature pressure leaching and direct electrowinning (DEW). Part III reviewed the large-scale demonstration of the MT-DEW-SX process at Bagdad, Arizona. Key features of the process were the use of superfine grinding of the concentrate (to a P98 of 12 to 15 µm and a P80 of 6 to 7 µm), pressure leaching at 160ºC with 1,380 kPa (200 psig) oxygen overpressure, DEW to produce LME Grade A cathode, recycling some of the lean electrolyte to the pressure leaching step, and treatment of a lean electrolyte bleed by solution extraction (SX). Recycling of lean electrolyte provided all of the acid required to effectively dissolve copper and convert approximately 65% to 70% of the sulfide sulfur to elemental sulfur, resulting in an acid-autogenous process for pressure leaching. This paper (Part IV) discusses the development and design of a full-scale commercial application for the Morenci operation in Arizona.

Jan 1, 2007

By Glen Church, Don W. Deere, Christoph M. Goss

The Standley Lake Dam Rehabilitation Project in Colorado included the complete replacement of the outlet works. This required two 1.8m (6 ft) diameter microtunneled wet lake taps, 380m and 186m (1246 ft and 636 ft) long, a permanent valve shaft 12.2m(40 ft) wide and 32m (105 ft) deep, and a 3.5m (11.5 ft) diameter (962 foot long) outlet tunnel driven with a roadheader. The tunnels were driven in low-strength, expansive, and slickensided claystone. The paper addresses the site investigation, shaft construction, roadheader performance, shotcrete placement, tunnel convergence, long distance microtunneling, and wet lake taps.

Jan 1, 2005