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By M. D. Dennis

Precious metal mineralization at Mt. Hamilton" Nevada is associated with a poly-metallic, garnet-pyroxene skarn system developed in middle to upper Cambrian calcareous shales, limestones and dolomites. The skarn is developed around the Cretaceous Seligman and Monte cristo calc-alkaline stocks. Gold is associated with intense retrograde alteration. Later epithermal quartz veins containing gold, silver, base-metal sulfides, and sulfosalts cross-cut skarn alteration. Westmont Mining Inc. is currently developing two mineralized zones containing a geologic resource of approximately 7.7 M.T., which averages 0.05 OPT gold and 0.5 OPT silver. The project will have an estimated mine life of seven years, with a planned annual production rate of 35,000 ounces of gold and 300,000 ounces of silver.

Jan 1, 1989

By J. M. Barker, V. T. McLemore

Most discussions of sustainable development (SD) in mining relate to metal mines in rural areas. Industrial minerals (IM) are closer to urban areas primarily owing to a high transport-cost component of delivered cost. This visibility to large populations overshadows IMs relatively small operation size and generally lower waste volume and toxicity. The IM industry needs to rethink its way of doing business to fit into the SD paradigm. Society and business in general will also undergo significant change to enable industrial SD along the lines of triple-bottom-line accounting with government pushing everyone. The benefit to IM mining from embracing SD is a renewal in their social license to operate and a rebirth of mining as a positively-viewed force in society. This positive view would lead to lower acquisition costs because society would not fight so hard to eliminate nearby mining. This would ease the current exploration woes of the IM industry by opening up new deposits for exploration and more readily allowing placement of mines nearer to markets. The earlier in the exploration process SD is initiated, the better.

Jan 1, 2004

By R. Corriveaau

This paper is about a horizontally curved conveyor, which carries 6,050 stph of limestone over land from a new quarry to the owner's plant. The conveyor is 5,012 ft long with a horizontal curve radius of5,OOOft Site conditions made a curved conveyor design the most optimal and economic solution. Using our unique custom conveyor calculation program, TKRI was able to accurately model and design the conveyor to properly track the belt and prevent any spillage through the horizontal curve radius. A data monitoring system was installed that allows monitoring of the conveyor both locally and remotely. The remote monitoring allows TKRI to contact the owner for preventive maintenance. Preventive maintenance can reduce the conveyor downtime during normal operating hours.

Jan 1, 2004

By J. Dubbert, T. H. Jones

"This paper describes a rib-control methodology that uses standing support to provide most of the lateral resistance to the rib. The method is analyzed, and its boundary conditions for rib control are described. In this method, an animal-fencing mesh product covers 80 percent of the rib surface and is sparsely bolted to the rib. Can supports or other similar stiff supports are installed primarily as roof support for the entry. As the rib spalls and dilates, the mesh catches the material and expands, pressing against the standing support. Mining proceeds, and vertical roof loads increase the normal force on the Can supports, causing friction at the top and bottom of the support to go up, thereby improving lateral resistance to rib swelling.At one mine in the western United States, this method has proved excellent at preventing the buildup of rib spall. It substantially reduces the number of bolts used for screen installation, improves installation efficiency, reduces manual labor and provides more rib coverage than many screening methods. Because standing support is typically part of the roof-control plan in longwall tailgates, no additional standing-support costs are incurred. IntroductionRib safety in underground coal mines is an oft-studied topic because ribs are high-hazard areas. An overview of early rib safety research can be found in Jones and Mohammed (2014). There is a significant difference between rib support and rib control. Support improves safety through the installation of strengthening elements, such as bolts and dowels, designed to reduce rib spalling. Although spall reduction is preferred, controlling how the rib fails is enough to ensure safety in some situations. Rib control uses external elements to provide confinement, thereby holding sloughed material in place, or to prevent falling rib material from striking mine personnel. This paper presents a study of a control method used on the pillar side of a longwall coal mine tailgate in the western United States."

Jan 1, 2015

By R. W. Macqueen

Organic matter commonly associated with Mississippi Valley-type (MVT) lead-zinc deposits may be used to assess the burial/thermal history of host rocks and sulfides. Organic matter may also have been involved in the genesis of H2S required to precipitate sulfide ores. Pine Point, Northwest Territories, Canada, provides an example. Located on the south shore of Great Slave Lake, Pine Point is an operating world class deposit which has produced 58 million tons of ore containing 3.0 percent Pb and 6.1 percent Zn from more than 40 Individual orebodies. Well-documented paleokarst features in a Middle Devonian carbonate complex are the main ore hosts. Sphalerite and galena ores are mainly open space fillings, and, from fluid inclusion studies, were deposited from saline fluids at temperatures of up to at least 100°C. Forms of organic matter occurring in the Pine Point barrier-reef complex Include indigenous organic matter, heavy oil and bitumen. Based on numerous geochemical criteria, it is clear that heavy oils and bitumens were derived locally from indigenous organic matter. The geochemical character of the Indigenous organic matter demonstrates that the barrier-reef complex is immature to marginally mature with respect to petroleum generation, and has not been heated above about 60°C maximum. Thus sphalerite with fluid inclusions that yield temperatures up to about 100°C represents former thermal anomalies. Bitumen is of two main forms at Pine Point: widespread soft, tarry material soluble in organic solvents (unaltered bitumen); and hard, brittle, glassy material that is mostly solvent-insoluble, and associated with white sparry dolomite and lead-zinc ores (altered bitumen). There are also partly altered bitumens. Unaltered bitumens have atomic H/C ratios of about 1.4, sulfur contents averaging 7.8 percent, and sulfur isotope ratios 634S) of approximately +4.6 per mil. Altered bitumens have atomic H/C ratios averaging 1.02, sulfur contents averaging 22 percent, and 634S values of about +12.9 per mil. These data and the organic geochemical character of a large suite of bitumen samples analyzed, strongly support the concept that some bitumen has been involved in the thermochemical reduction of sulfate to produce the H2S required to precipitate the ores. Mass-balance calculations indicate that the amount and degree of alteration of bitumen is more than enough to account for the reduced sulfur species deposited as metallic sulfides at Pine Point. MVT deposits, including Pine Point, seem to require the coincidence of available metallic Ions, pre-existing pore space, and a precipitating agent. A close look at organic matter in more MVT settings may outline trends in distribution or alteration which can be used as indicators of past thermal environments and processes of ore deposition.

Jan 1, 2013

Little faith can be placed in a coal resource estimate without a clear understanding of the estimate's accuracy. Different types of coal resource estimates require different levels of accuracy. Prospecting surveys typically are done with widely spaced boreholes, while a much higher level of accuracy is required for mine design. Either way, a measure of the accuracy clearly indicates the level of confidence that can be placed in the results of the estimate. Geographic information systems (GIs) are becoming a commonly used tool for resource estimation because they not only provide a database management platform but also the graphical capabilities to visualize resource characteristics. interpolation methods used commonly in these resource studies do not typically provide a quantitative answer to the question: "How accurate is the estimate?" By comparing localized measurements at multiple locations to the interpolated thickness distribution used in a resource estimate, a quantitative analysis of accuracy can be obtained. The technique is demonstrated with a case study from Central Appalachia.

Jan 1, 2000

By J. M. Hird

By blending phosphogypsum with thickened mill clays, Texasgulf has successfully resolved the problems of gypsum disposal and reclamation of mined-over areas. In the process, clays are thickened to 10% solids through high rate thickeners, mixed with gypsum from a drained gypsum pile (75%) and a direct discharge from belt filters (25%), then pumped to mined-over areas. The blending of clays and the low pH gypsum yield a mixture with a pH of about 7. Dewatering is rapid to 40-45% solids within 3 months. The material spreads with very shallow slopes and within a year desiccation by high flotation ditching equipment is possible. The artificial soil is classified as a silty loam in texture, lacking only in nitrogenous nutrients. The soil material has proven to support many field crops including small grain, corn, alfalfa, and grasses. Sycamore, green ash, sweetgum and bald cypress have done well in 3 years of growth. The nitrogen source for tree growth will be made up through an alfalfa cover.

Jan 1, 1993

By Gregory Yates

INTRODUCTION Project Description The Silver Line is a Bus Rapid Transit (BRT) Line and is Boston?s newest transit service. Silver Line Phase I extends along Washington Street entirely on the surface in priority bus lanes from Dudley Station in Roxbury through the South End and Chinatown neighborhoods to downtown Boston. The Phase I opened in July 2002. Silver Line Phase II consists of an underground transit tunnel from South Station to the South Boston Waterfront with underground stations at Courthouse and World Trade Center to Silver Line Way east of D Street. Phase II continues through the Ted Williams Tunnel to all the terminals at Logan Airport, and on the surface to the Boston Marine Industrial Park and City Point. Phase II opened in December 2004. Silver Line Phase III is a one mile tunnel connection to the existing Phase II tunnel in the vicinity of South Station and will eventually portal on Tremont Street just north of Marginal Road. After leaving the portal, the buses will use dedicated bus only lanes on the surface roadway network to connect to the Phase I service. Figure 1 shows the alignment of the Silver Line upon completion of the Phase III project.

By J. Chae, D. Pecha, R. Andrews

The Henderson/ML King CSO Project is a major combined sewer overflow (CSO)reduction project for the Department of Natural Resources and Parks of King County, Washington. The central element of the project is the 3100 lineal feet long, 14'-8"diameter 42nd Ave S Storage/Treatment Tunnel. During the course of the project, the owner and consultants evaluated numerous elements of the tunnel including the alignment, geotechnical conditions, tunnel liner, and settlement monitoring requirements. The contractor utilized innovative shaft construction methods for the tunnel portals, and adhered to strict contract requirements in successfully constructing the tunnel. This paper provides an overview of the design and construction elements of the 42nd Ave S Storage/Treatment Tunnel that led to the successful completion of the project.

Jan 1, 2005

By J. Stowe

"While there has been continual improvement in the models for predicting deposition velocity and pipeline friction losses, the fundamental design philosophy for tailings pipelines has remained the same over the previous three or four decades: design the tailings pipeline to operate in turbulent flow without a deposit on the pipe invert for all expected process conditions. Recent improvements in the understanding of slurry pipeline flows allows for the design of pipelines operating with a deposit on the pipe invert, allowing the system to operate at moderate velocities for high flow rates, optimizing system energy requirements and maximizing pipeline wear life.Tailings pipelines are increasingly operated at higher solids concentrations when there is a greater likelihood the pipeline will operate in laminar flow due to the higher tailings slurry rheology. Historically, slurry pipelines have been operated in turbulent flow. We now know that laminar-flow pipeline operation is possible as there are several operational laminar-flow tailings pipelines. While our understanding of laminar-flow slurry pipelines is not complete, recent research provides guidance on how to approach the design of these pipelines.New sensor technology has led to the development of an instrument that provides reliable indication of bed-deposit height within a pipeline. This technology is particularly helpful in operating pipelines with a deposit and has application in better understanding the operation of laminar-flow pipelines. Failure of tailings pipelines can result in consequent damage to surrounding structures and unacceptable spillage into the environment. Modern pipeline leak detection technology allows operators to better manage this risk by ensuring safe and reliable operation of tailings pipelines.This article provides an overview of the each of the above advances in the design and operation of tailings pipelines.Operating tailings pipelines with a depositTailings pipelines, and slurry pipelines in general, are typically designed to operate without a deposit on the pipeline invert. Meaning, the minimum operating velocity exceeds the turbulent deposition velocity. This approach has been adopted due to concerns regarding potential blockage of a pipeline operating with a deposit."

Jun 1, 2019

By Steve Skelhorn

Edmonton South LRT is the latest expansion of the Subway system in Edmonton, Alberta, Canada: Consisting of twin 5.8m segmental lined tunnels, 280m long, driven by a Lovat EPB machine. The key challenges were as follows. A 6% downhill grade. Tight radius curves of 250m.Overlying structures within 3m of the tunnel. Strata consisting of sand above the water table, glacial tills and bed rock below the water table. Located within The University of Alberta Campus and adjacent to a hospital. Northern Alberta climate with winter temperatures routinely falling below—minus 30 degrees Celsius. This paper provides a case history and outlines the challenges involved in completing this project.

Jan 1, 2005

By B. K. Blashich

In responding to mine fires and explosions, accurate and timely analysis of the mine atmosphere is critical in making decisions regarding firefighting, mine rescue and mine recovery operations. For many years instantaneous analyses were available to rescue workers using handheld or portable gas detection equipment, including infrared, electrochemical, or catalytic measuring devices for a limited number of specific gases such as oxygen, methane, carbon monoxide and carbon dioxide. Instantaneous sensing technology is not available for all gases, such as nitrogen and hydrocarbons, found in a mine fire atmosphere and cross-sensitivity can be a problem with this technology. For these reasons, air samples are collected for injection into a gas chromatograph for a complete and accurate analysis for all gases including oxygen, nitrogen, methane, carbon monoxide and carbon dioxide, as well as ?fire gases? such as hydrogen, ethylene, ethane, and acetylene. This method requires additional time for transporting the samples to the laboratory near the mine, as well as an instrument operator to inject the samples for analysis. The use of a portable micro gas chromatograph with a continuous and automatic injection system has been implemented by the Mine Safety and Health Administration (MSHA) during mine recovery operations. The device directly samples the mine atmosphere from an underground location every twelve minutes and automatically analyzes the samples for all of the mine fire gases. The portable unit utilizes micro technology and the operating software has been modified to perform the calculation of sample results in and Excel® spreadsheet without user interaction. This paper describes the micro gas chromatograph system and its use at a recent mine recovery operation. The automated remote operation of the micro gas chromatograph has been shown to be a good alternative to infrared and electrochemical sensors used for mine atmosphere analysis.

Jan 1, 2009

By Daniel H. McClain

A unique partnership between the Colorado Mine Safety and Training Program (CMSTP), the Colorado Rock Products Association (CRPA) and the Higher Education and Advanced Technology (HEAT)Center resulted in a video CD-ROM training program for new miners entering the aggregate industry. Cooperation from everyone involved, including the U.S. Mine Safety and Health Administration (MSHA),made this the product against which other training materials in the mining industry will be measured in the 21stcentury. This product’s versatility and wide application make it a tool that is as critical to a mine’s success as any earthmoving machine. The state and federal grant money involved allows this product to be affordable to small operators and independent contractors. The quality of this two CD-ROM set rivals any commercially made CD-ROM training.

Jan 1, 2003

A knowledge of airway friction factor (K-factor) is necessary to designing mine ventilation systems for least cost and optimum effectiveness. The friction factor used must be accurate and reliable to estimate correctly roadway resistances and pressure sources for required flows. Though the resistance to flow offered by mine airways has been an object of study over the last half century, no accurate relation has yet been established from which the prediction of the resistance of a projected airway can be made. In Kentucky, only limited and incomplete data on local K-factors are available. Therefore, there is a need for field investigations to determine these values in-situ for existing mining conditions. The author describes a study concerning K-factor that was carried out in ten coal mines, located in eastern and western Kentucky. The results of these investigations are presented in both tabular and graphical form.

Jan 1, 1991

By Sunny Schoone, Maximilian Getz, Felix Leaman, ELISABETH CLAUSEN

Hydraulic transport is commonly used in mining for moving particles or ore concentrates in pipes over long distances with a water stream. Control and monitoring of this process require sensor technology that can obtain relevant characteristics of the two-phase flow. This work investigates the acoustic emission (AE) technology for monitoring a hydraulic system with different sand concentrations, showing the strong relationship between friction behavior in the pipe and the measured AE signals.

Apr 1, 2023

By Colin Lawrence, Michael S. Schultz

Due to the planned deepening of the NY Harbor, NYCEDC/NYCDEP is planning to replace two existing water lines between Brooklyn and Staten Island with one deeper water pipe. The crossing, just north of the Verrazanno Bridge is 1.75 miles long. The new pipeline will be tunneled using gasketed concreted segmented liners. Apressurized face machine will be used through the soft ground. This will be the first subaqueous application using this technology in New York City. This paper discusses the planning, design and risk issues associated with the crossing and the challenging soil conditions that resulted in the decision to use a pressurized face machine.

Jan 1, 2007

By N. J. Themelis, W. H. Dresher

Research is probably the least understood and the most underrated or overrated, depending on the circumstances, function of the corporate enterprise. Some companies become engaged in research because they consider it to be vital to their very existence, others in order to develop new business, and some with no clearer objective than to keep up with the competition. Whole new industries have resulted from research activities, such as the Xerox copier, the transistor, the computer, and have affected considerably our way of life. Companies have prospered or perished by pursuing the successes or failures of their research organizations. However. despite the tremendous effect that research has had on our modern civilization and the billions which are spent on it annually, we have not as yet been able to develop many hard and fast rules as to how to conduct it effectively and to a successful end.1 This section discusses the role of research in the United States and in the mineral industry and describes a few of the criteria and guidelines which have been developed to assist in increasing the probability for success in industrial research. Broadly speaking, the purpose of industrial research is to make a significant contribution to the long-term viability and the profitability of the sponsoring company. The sum total of technological developments has been a principal factor in establishing the United States as a world leader and the controlling element in the nation's balance of trade with foreign powers. The international aspect of most mineral commodities is a significant factor in the business decision-making of most domestic mining companies and should be an important factor in the operation of research and development (R & D) programs in these companies. The National Science Board has reported that in recent yean other nations have been gaining on the United States over practically the entire range of science. 2,3 On the positive side, the NSB reported a strong position for the US in the results derived from its investment in R & D. If the United States is to maintain a favorable trade balance, it must create new know-how through technological innovation in order to create new industrial products, processes, and services for which there is a global demand. As expressed by Chauncey Starr, president of the Electric Power Research Institute, "Unlike resources found in nature, technology is a man-made resource whose abundance can be continuously increased, and whose importance in determining the world's future is also increasing."' In recent years, the greatly in- creased pressures for environmental quality and energy conservation have enhanced further the role of technical innovation in insuring the future survival of the domestic industry. Technology is the challenge of American industry, and it is a challenge which the mineral industry must also accept, for processed minerals are the very raw materials and energy on which all of industry is based, it is technology which makes a mineral deposit into an ore reserve. The Natural of Industrial R D Research is usually thought of as being either basic or applied. Basic or fundamental research is the quest for knowledge and need not have any practical objective. Applied research is the search for a solution to a particular problem and therefore has a specific objective beyond the acquisition of new knowledge. Development is the next stage to the applied research experimentation and it generally consists of larger-scale tests to establish the technical and economic feasibility of the new process or product and to provide design information for its industrial implementation. The terms research and development are usually interconnected for the good reason that in many cases it is difficult to define where one ends and the other begins. For instance, in many cases, thermodynamic, kinetic, corrosion, and other research studies, which are needed to provide design data for an industrial plant, may prod in parallel with the pilot plant activities preparatory for this plant in order to conserve time. Often the final stages of a development project may involve the trial production of a new product for markeing tests or the trial operation of a new process on a "semi-industrial" scale pilot plant. Such operations may be termed "demonstrations"; hence, more

Jan 1, 1985

By H. Michael Breza

Texasgulf Inc. installed bucketwheel excavators and overland conveyor sysems at its Aurora, NC phosphate mine o increase the productivity and flexibilty of the surface mining operation. This ;ystem has significantly improved overrall. Its flexibility is evidenced by adapation to operation requirements, such is mining area moves, movement of xcavated overburden to designated ites, selective handling of overburden, poll placement contouring, and proiding an environmentally sound and afe operation. The system's productiv:y is evidenced by case studies relating. overall production, excavation rates nd cost-effectiveness. There are many competing alternaves available for excavating uncon)lidated overburden: truck-shovel, raglines, dredges and bucket wheel ticavators. These alternatives also may used in tandem to recover reserves icated at greater depths.

Jan 1, 1993

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 S. D. Thompson

An AIME transaction by P.L. Allsman (1960), "Analysis of Explosive Action in Breaking Rock," contains many useful concepts applicable to blast design. Of special interest was the derivation of a heave blasting burden formula, which is important in establishing the maximum burden. Unfortunately, its derivation contains a fundamental error and then a compensating one. This formula was: [ ] The derivation used the impulse-momentum principle, with a 0.3 m thick (1 ft thick) radius of rock mass being acted on by an explosive impulse. However, the rock weight was not converted to mass by dividing by the gravitational constant. This mistake can be verified by checking the units in the formula, which resolve into m%-sec instead of meters. Adding the gravitational constant corrects this: [ ] If the minimum velocity is now taken as 0.3 m/sec (1 ft per sec), as was recommended, excessively large burdens result. Any appropriate rock velocity should be capable of throwing the rock mass a minimum distance so that the swell needed for breakage can occur. Unless the burden is extremely small and the bench height is very high, it is unlikely that a velocity of only 0.3 m/sec (1 ft per sec) will be sufficient. A review of the literature indicates that average rock velocities observed by camera studies typically range from 15 to 30 m/sec (50 to 100 ft per sec) (duPont deNemours and Co., 1977; Tansey, 1979). On this basis, a minimum rock velocity of about 15 m/sec (49 ft per sec) would be expected and not 0.3 m/sec (1 ft per sec). When a velocity of 15 m/sec (49 ft per sec) is inserted into the corrected formula, the results approximate those of the original formula with a velocity of 0.3 m/sec (1 ft per sec). The errors were approximately self-compensating [ ] References Allsman, P.L., 1960, "Analysis of Explosive Action in Breaking Rock," Transactions, AIME, Vol. 217, pp. 475-476. E. I. duPont deNemours and Co., 1977, Blasters' Handbook, 175th Anniversary Edition, Dupont, Wilmington, DE, pp. 233. Tansey, D.O., 1979, "The DuPont Sequential Blasting System," CIM Bulletin, Vol. 72, July, p. 80. Thompson, S.D., 1981, "Critical Review and Revision of Surface Blasting Practice," MS thesis, West Virginia University, pp. 308-316.

Jan 3, 1985