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By C. Orf. Chukabarah

Erratic behavior in convergency during iterative numerical-method evaluation of mine ventilation fan characteristic curves is one of the common problems encountered in mine ventilation network analysis. Five different sets of mine fan data points, that had resulted in unsatisfactory fan characteristic curves, were re-analyzed in the present study, using an embedded mine network optimization computer program. Current results revealed that all five fan data sets not only can be satisfactorily fitted as Yang (1992) did with MFIRE subprogram, but can further be optimized with unique solutions as implemented in the present study. It was concluded, inter alia, that the improved MFIRE-based mine fan curve-fitting computer subprogram (SPLINE) produces satisfactorily similar fan curves as SPSS-based curve-fitting algorithms, including when the latter method uses either standardized or unstandardized fan curve data sets.

Jan 1, 1993

By Jim Peregoy

INTRODUCTION Frontier-Kemper Constructors, Inc. is an Evansville, Indiana based heavy construction contractor engaged in projects for both the public and private sectors of the underground construction industry. Construction activities range from conventional shaft, slope, tunnel and chamber excavation through state-of-the-art mechanical excavation, ground freezing, standard support and structural concrete operations. Conventional excavation and concreting equipment, as well as raise boring machines, road headers, tunnel boring machines, and freeze plants are owned, operated, maintained and modified "in-house" to suit the needs of individual projects. The balance of this paper wilt present a general overview of the Frontier-Kemper planning and construction operations on the recently completed Phase II of the U.S. Army Corps of Engineers, John Day Dam, Juvenile Fish Bypass Project. General Project History The U.S. Army Corps of Engineers is responsible for designing, constructing and maintaining various navigation and impoundment structures on the nation's inland waterways. Maintenance involves both the work required to maintain the structure in fully-operable condition and the ongoing work required to maintain a positive impact on the environment. John Day Dam is located on the Columbia River approximately 95 km (60 miles) upstream of The Dalles, Oregon. It was constructed to: provide electric power to the Pacific Northwest; provide Locking for up-and-downstream bound commercial and private watercraft; act as a water impoundment structure to control flooding conditions; and to provide a source of irrigation water

Jan 1, 1987

By E. J. Karges

[For reasons well known to Mining Engineers, fine grinding in the wet form is quite universal inn plants engaged in the traction of metallic values from crude ore In the processing, of non-metallic and industrial minerals, however, fine grinding in dry form is the more common method. The crude materials generally contain less moisture than required for wet grinding, and the products are usually marketed or used in the dry form, most of them as powders. To grind wet would therefore entail the addition of water and the expense for drying the product, which is not justified. This paper will concentrate on the particle size reduction or fine grinding of materials to produce a dry powder]

Jan 1, 1963

By V. B. Achanti, A. W. Khair

Laboratory studies were carried out at West Virginia University to investigate the rock fragmentation mechanism by continuous miners using an automated rotary cutting simulator. The primary factors influencing the fragmentation process were found to be: bit spacing, bit geometry, depth of cut and cutting drum rotational speed. This paper presents the influence of these parameters in achieving optimum energy consumption and minimizing dust generation during rock fragmentation process. Tree bits were used simultaneously on Indiana limestone while the bit tip angle was varied from 60° to 900. Bit spacing was varied from 2.54 cm (1 in.) to 5.08 cm (2 in.) while the cutting process was assessed for varying cutting depths. Restorable dust generated during the course of the experiments was analyzed utilizing cascade impactors. Assessment of these parameters has led to a better understanding of the cutting mechanism by continuous miners in terms of energy consumption and dust generation.

Feb 24, 1997

By R. J. Pruett

The Georgia kaolin district is the world’s largest producer of kaolin. Georgia production tripled from 2.87 Mt (3.17 million st) in 1968 to8.35 Mt (9.2 million st) in 1998. Development of the Georgia kaolin industry can be traced to the identification of the mineral resource, the adoption of innovative process technologies and the creation of markets for kaolin. Georgia kaolin is an abundant and high-quality resource that shows a range of advantageous properties. Technical developments in wet processing, delamination and calcination allowed production of high-value products. The use of kaolin pigments in the paper industry provided a market that absorbed the rapid growth in kaolin production.

Jan 1, 2000

By K. L. Kasperski, M. T. Ityokumbul

The effect of reaction conditions on the desulfurization of oil-sand coke residues was studied. The variables investigated were temperature, reaction time, heat transfer resistance and mode of caustic soda addition. The results show that oil-sand coke desulfurization increases with temperature, reaction time and heat-transfer rate. In an oxidative environment, coke combustion during molten-caustic leaching (MCL) commences at temperatures above 500 °C. The mode of caustic addition has no effect on coke desulfurization.

Jan 1, 1996

By W. J. Schlitt, J. H. Templeton

The chemical reactions that occur within a copper-leach recovery system are discussed, and the impact on the overall acid balance is evaluated. Both oxide and sulfide mineralogy are addressed, and their effects on acid consumption, generation and solution buffering are presented. Two case studies that apply the discussed chemistry show the practicality of using a computer spreadsheet acid-balance model for the early planning and design of copper-leach systems.

Jan 1, 1998

By None None

Use this month wisely — go online and take advantage of your new member benefit. As an SME member, you can read and download for free all of the full-text papers of the Mining, Metallurgy & Exploration (MME) journal, including the 22 papers in the launch Special Issue on Mineral and Metallurgical Processing in Honor of Professor Emeritus Douglas W. Fuerstenau as well as the archived articles of Minerals & Metallurgical Processing (MMP), all the way back to Vol. 1, No. 1. Just follow the instructions on this page.

By Lynn Salvati, Colin LaVassar, Loic Galisson, Joel Theodore, Lynette Sla

"Sound Transit’s University Link and Northgate Link projects will add 6.75 miles (10.9 km) of twin-bored tunnel to Seattle’s light rail system, extending the route north from downtown Seattle. The tunnels are being constructed primarily in glacial soils using pressurized-face tunnel boring machines. Cover over the tunnel alignment varied from 13 feet to over 300 feet (4–91 m). Since the tunnels are located in densely populated urban areas, controlling ground movements and monitoring settlement were essential to success of these projects. Hundreds of geotechnical instruments, including extensometers, surface settlement points, and near-surface settlement points, were used in both projects to monitor settlement. The observed data were compared to settlement predictions made prior to tunneling, and analyses performed to update empirical factors to better estimate settlements. Recommendations for designing efficient and cost-effective settlement monitoring programs are provided based on the review of the monitoring data and analyses.INTRODUCTIONThe paper includes data from Sound Transit’s University Link and Northgate Link projects. These projects will add 6.75 miles of twin-bored tunnel to Seattle’s light rail system. The tunneling for University Link will extend the light rail system from downtown Seattle to the University of Washington. Tunneling from downtown Seattle to the Capitol Hill Station was completed under the U230 contract, and tunneling from the Capitol Hill Station to the University of Washington Station was completed under the U220 contract. The Northgate Link extension will extend the light rail line north of the University of Washington, including approximately 3.5 miles (5.6 km) of twin tunnels between the University of Washington Station and the Maple Leaf Portal and two stations, U District Station and Roosevelt Station. Tunneling for the Northgate Link project is still underway as part of the N125 project. At the time of writing, tunneling from the Maple Leaf Portal to Roosevelt Station has been completed. Therefore data labeled as N125 in this paper only include the portion of the alignment from the Maple Leaf Portal to Roosevelt Station."

Jan 1, 2016

By Mark E. Gershon

Extensive efforts are under way to- ward applying computer techniques to mine production scheduling problems. These efforts are concentrated in four areas: optimization, computerization of traditional methods, heuristics and simulations. These areas complement each other rather than compete. Characteristics of each are discussed toward enabling the engineer to evaluate specific systems that may be encountered. Alternative approaches within each classification are described as well as the motivation for each.

Jan 1, 1985

By Jon Y. Kaneshiro, John S. Griffith, Anthony F. Stirbys, Mauricio Andrade

This paper presents an overview of the New Mississippi Tunnel Outfall for the Transportation Expansion Project (T-REX). The Outfall conveys highway and other urban drainage to the South Platte River as well as provides long needed relief from flooding problems in the southeastern portion of the Interstate 25 highway corridor. The Outfall tunnel incorporates a one-pass precast concrete segmented liner to convey storm water under I-25 then under Mississippi Avenue to the river. The Outfall crosses both the existing I-25 as well as the future improvements including under the Light Rail Transit, a new bridge abutment, widened lanes, and new retaining walls. The Outfall also crosses adjacent to several buildings and five bridges, under major traffic and utility intersections, and through difficult geology.

Jan 1, 2003

By P. Sotiropoulos

In the framework of the Specific Programme: ?Promoting Competitive and Sustainable Growth? a detection system was designed and developed in order to provide an added value service beyond standard instrumentation. In the hydrocarbon industry it will be possible for the first time to detect in a pulse regime, two types of radiation emissions using a single device. This means that any saturation of hydrocarbons can be detected, irrespective of the degree of formation water mineralization, which is a major limitation on currently available neutron-gamma tools, where the formation water has a low mineralization.

Jan 1, 2006

By J. W. Oberholzer

This paper describes research being undertaken by the Chamber of Mines Research Organization (COMRO) which is designed to assist the continuous miner operator and section foreman in the performance of their jobs. The project will initially provide visual assistance to the miner operator, and later will semi-automate the mining (cutting) process. Using a technique known as "RF tagging," the project will also provide real-time or near-real-time information about the performance of the loading and hauling units to the section foreman, allowing him to quickly detect problems and take action where appropriate. The project is based upon the application of currently available technology, and the first phase is scheduled for in-mine testing within the next year.

Jan 1, 1991

By V. M. Torres

An empirical correlation to detennine laboratory mill grinding time has been developed. Grinding samples to 90 ± 5# below 147 micrometers was required for a flotation testwork at Companhia Vale do Rio Doce (CVRD) Research Center. The initial samples were all below 1 mm in size with different size distributions and work indices (Wi) ranging from 13 to 23 kWh/st. Grinding curves were determined for some initial samples. A correlation was developed between percent retained on 147 micrometers at a standard time and the time required to grind each sample to the required size. This correlation was then used to grind all samples, based on the preliminary grinding model. Finally, a statistical analysis with the size distribution of all samples was performed. The success of using the correlation was confirmed and an equation was determined using the data set.

Jan 1, 1996

By Amanda Elioff

Success of the Gold Line Eastside Ex-tension rail tunnels in Los Angeles, CA has prompted the Los Angeles County Metropolitan Transportation Authority?s (Metro) planning new rail lines to include underground alternatives. The Westside Extension Transit Corridor alternatives include up to 27 km (17 miles) of subway to be constructed in soft ground. The routes will require construction in Los Angeles? ?potential methane zone,? which was not considered for subway construction until recently. Slurry face tunnel boring machines (TBM) will likely be specified.

Jan 1, 2009

By R. E. Chaves

San Martin Mine is an open pit, gold heap leach operation located approximately 70 kilometers from the Honduran capital of Tegucigalpa. Mining operations commenced in 2000 and were completed late in 2007, while heap leaching operations continue. Reclamation was executed concurrently with operations to the extent practical. The area has distinct rainy and dry seasons and closure objectives include: prevention and mitigation of acid rock drainage, sediment and erosion control, and mitigation of visual impacts. Final closure is well underway at San Martin and this paper describes the closure processes conducted to date, problems encountered, and the subsequent lessons learned.

Jan 1, 2009

By B. P. Faulkner, M. Weinecke

Svedala started a development program in 1997 to develop a process to convert waste tires into valuable commodities. A review of numerous approaches revealed short-comings in the various approaches either process, mechanical, combination of factors, or trying to emphasis the production of low value products. A market study revealed that a process that could produce a good grade of carbon black would be economically feasible. This paper discusses the laboratory and pilot plant development and commercial plant design.

Jan 1, 2001

By John Frostiak, Igor Gonzales, Kenneth G. Thomas, Ken Manning

The Pierina deposit was acquired in August 1996 when Barrick Gold Corporation purchased Arequipa Resources, a junior mining company with extensive land positions in Peru. At the time of acquisition, Arequipa ha.d developed two exploration tunnels and drilled 9 exploration holes on the property. Metallurgical tests, conducted on samples taken from the tunnels and the exploration holes indicated that the ore was amenable to heap leaching. Barrick's exploration team recognised from the outset, the potential of the mineralisation and convinced Barrick's senior management that this was indeed a world class deposit that should be pursued. On November 25, 1998, the fi was poured at Pierina, 27 months from the time of acquisition. During that period BmTick completed its exploration programme, prepared a development plan including capital and operating costs, production profiles and cash flow forecasts, and a schedule to develop a mine and construct a leach pad and gold recovery plant, including all supporting infrastructure. All permits and environmental approvals were obtained and all necessary land was acquired. The project was completed on schedule and under budget. This was the first greenfield mine development for Barrick outside of North America. This paper details, mainly, the research and development, engineering, construction and commissioning of the metallurgical process facilities.

Jan 1, 2000

By Susan L. Bednarz

Recent advances in digital cameras and image processing allow photographers to produce excellent high-resolution action shots in low light and high contrast conditions commonly encountered underground. Digital photography is often used for construction and inspection documentation for underground structures. Designers, owners, and contractors benefit from quality photographs that document incremental progress and project milestones. Documentation photos serve as a lasting record of as-built conditions, are an important marketing tool, and help the owner build public support for expensive public works projects. When the project is complete, the only mementos that the participants will hold onto are the photographs.

Jan 1, 2008

By J. Alton Burks, Roy C. Bartholomae

The chain conveyor is utilized extensively in underground mining to convey raw ore, especially coal. It is estimated that several thousand loading and continuous mining machines rely on this type of conveyance. Although the chain conveyor is both efficient and highly reliable, its use is generally associated with the production of noise levels that often exceed 105 dBA at the operator's position. Thus, it is one of the most significant contributors to the occupational noise problem experienced by miners in the underground coal mining environment. Conventional engineering noise controls that result in an average reduction of 4 dBA have been previously designed and implemented. However, a novel solution involving a change in conveyor operation has been proposed that takes advantage of two aspects of conveyor noise: 1) conveyor noise has an approximately cubic dependence on conveyor chain speed and 2) due to the damping provided by coal, a full conveyor is 5 dBA quieter than an empty one. An engineering analysis has shown that a significant reduction in the operating noise level of a typical continuous miner can be achieved through the use of an adjustable speed drive automatically controlled by a coal loading sensor that maintains a full conveyor at all times. The potential reduction depends primarily on the mining conditions (coal seam thickness and the presence of either rock or water) and varies from 7-18 dBA. Other benefits to be derived from the use of a variable speed drive include reductions in power consumption, dust, and maintenance costs.

Jan 1, 1992