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By D. Bogh

Wound rotor motors are used in difficult mining applications where there is a need to start high inertia, hard starting loads while limiting inrush current They are recognized as robust and simple to control. This paper will cover the performance, specification, and important issues to be considered when applying medium voltage wound rotor motors in mining applications. Medium voltage grinding, crusher, and conveyor applications will be discussed. Specifically covered are motor efficiency, speed range, and rotor control. Crane motors often have wound rotor construction, but their load cycle and ratings are outside the scope of this paper.

Jan 1, 2011

By Samuel J. Gambino

Preliminary recommendations for the Upper Northwest Interceptor 1&2 specified installation of reinforced concrete pipe using pipe-jacking methods. However, a larger one-pass tunnel constructed using precast segmental lining would provide additional storage volume. The risk of encountering unexpected conditions or events and the resulting cost impacts could differ significantly for these two options. A probabilistic life-cycle cost analysis of these alternatives was performed. This paper discusses the construction alternatives considered, the risk assessment methodology used to evaluate these alternatives, the input parameters and risk factors used in this analysis, and the recommended project which is currently being constructed.

Jan 1, 2008

By E. M. Van Eeckhout

The National Uranium Resource Evaluation Program (NURE) has produced a mass of geochemical data in the form of data files on tapes. This paper presents a methodology for utilizing those tapes in a simple, practical manner. An example is given of an analysis of the Butte quadrangle, Montana, tape obtained from the Los Alamos National Laboratory (LANL). The example details the sequence of splitting the data file, plotting histograms, cumulative frequency curves, concentration plots, and methods for evaluation. All programs are written in FORTRAN. The case study was performed using a mini- computer (DEC PDP 11/70) and standard plotting subroutines.

Jan 1, 1982

By S. G. Haycocks, M. Karmis, C. Haycocks

Risk assessment is a primary factor in the decision to mine some near surface orebodies, such as limestone, by either surface or underground methods. Identification and quantification of risks demonstrate that environmental concerns are greater for surface operations than underground, and may include such factors as runoff, spoil piles, aesthetics, dust, and large site reclamation. Risk assessment also includes local public feeling towards surface and underground operations while considering the balance between environmental impacts and the economic effects of mining on the local community. A complete understanding of the risks involved permits a comprehensive and accurate comparison between the two mining alternatives.

Jan 1, 1992

By D. M. Bodily, R. Jin, W. Hu

Four methods to assess the relative floatability of fine coal have been tested: flotation with frother only, salt flotation, timed-release analysis, and flotation with frother and collector. A practical and simple criterion that combines the separation efficiency (capacity factor) and kinetic rate constant (intensity factor) has been suggested. Five coal Samples from Utah were tested. Based on test results, it was concluded that the floatability test with collector and frother is closer to practice, and according to the suggested floatability criterion, coal fines can be classified into four categories of relative floatability: very easy, easy, moderate, and difficult.

Jan 1, 1988

By Dwayne C. Kicker, Duk-Won Park

As the use of longwall mining increases in the U.S.. there is a need to better understand the stress redistribu- tions indicative of this method. To control high stress concentrations, the yield pillar concept has been developed. A physical longwall mine model has been designed to study the effect of yield pillars in deep mining. The model in- cludes sensitive stress measuring devices, a new excavating technique, and a new model material. This study includes the use of both regular and yield pillar systems and has successfully simulated the mode of stress change in chain pillars.

Jan 1, 1986

By D. W. Hendrickson

Cleveland-Cliffs views the mining process as ex- tending from mine planning to cargo loading including auxiliary systems such as materials handling and plant utilities. Process automation is recognized as an area that can provide significant improvement opportunities with less capital requirement than major flowsheet modifications. This article discusses the development and results of a strategy to allow and promote implementation of process-automation improvements at individual mines based on their economic priorities, taking advantage of common systems and concepts for use at multiple mines where practical. Specific process-control upgrade projects at Hibbing Taconite Co. and the Empire Mine are reviewed.

Jan 1, 1998

By Z. Sartowski, M. J. Pearse

The authors present laboratory and plant results illustrating the benefits to be gained by using chemical additives, namely flocculants and surfactant dewatering aids, in the Bayer process. Advantages of synthetic flocculants over starch are illustrated in terms of more efficient solid/liquid separation in both the initial settling of blow-down slurries and in the CCD wash train. In addition, it is shown that the use of synthetic flocculants considerably reduce the levels of organic contaminants present in the process liquor. Secondly, very significant improvements in moisture removal were obtained by the application of dewatering aids to hydrate filtration/ washing operations.

Jan 1, 1984

By Terry Ritzel

Predictive maintenance technologies include vibration analysis, tribology, infrared thermography, ultrasonic detection and electrical measurements. These technologies have been applied to large electric mining shovels at the Cyprus Sierrita Mine outside of Tucson, AZ. The predictive maintenance program was initiated on the P&H models 2300 and 4100 electric shovels during August 1996. Results of these technologies have shown the potential for improving electric min- ing shovel availability and minimizing maintenance costs. Predictive technologies provide the tools to assess machinery condition. Availability is enhanced by the condition-based planning of component replacement. Maintenance costs are minimized by focusing resources through condition-based prioritization.

Jan 1, 1997

By A. Halim, A. Martikainen, S. GYAMFI

This paper outlines a unique case of the development of strategies to reduce ventilation and heating costs in Konsuln iron ore mine in northern Sweden. The mine, located just south of Luossavaara-Kiirunavaara Aktiebolag’s Kiruna iron ore mine, was developed as a test mine from 2018-2020 for the Sustainable Underground Mining (SUM) project. Besides functioning as a test mine, Konsuln also contributes to ore production. The existing mine ventilation system was designed for the current production rate of 0.8 million tons per annum (Mtpa). There is a plan to increase this rate to between 1.8 and 2.0 Mtpa.

Dec 23, 2021

By W. Zitz

Incorporation of heat exchangers into drilled shaft foundations is a novel approach to both improve the energy efficiency of building heat pump systems and provide necessary structural support using the same construction materials. In an effort to quantify the structural and heat exchange performance of deep foundations used as ground-source heat pumps, two instrumented test foundations were constructed as part of a new construction project in Denver, CO. They will be integrated into the conventional ground-source heat pump system for the building. This paper focuses on the lessons learned from the construction process for these energy foundations.

Jan 1, 2011

By P. Otto, G. Borm, Th. Dickmann, F. Amberg, R. Giese

Based on many years experience, the well approved Tunnel Seismic Prediction System (TSP) has been substantially enhanced for online geological prognosis in underground construction. The method provides high resolution seismic images of the rock mass ahead of a tunnel face via an array of standard anchor rods. These contain3D-geophones and can routinely be installed during the excavation process. A further outstanding feature of the system is the newly developed high frequency repetitive seismic source which can easily be fixed at a tunnel boring machine. A user-friendly software package enables online data acquisition, processing, 3D-visualization, and interpretation.

Jan 1, 2001

By M. S. Hunter, Al Bishop

In 1994, Lone Tree Mine invited Hunter Hawk to participate in a problem-solving arena at their mine located in Valmy, Nevada. Lone Tree was experiencing consistency problems with autoclave valve component quality and delivery. Based upon a prior working relationship at Homestake Mining Company's McLauglin Mine, located in Lake County, California, both customer and vendor enjoyed a measure of rap­po1i and trust - the keys to problem solving communication. This paper is an overview of the problem solving process that has contributed to Lone Tree's excellent record of 95 per cent autoclave availability since 1995.

Jan 1, 1998

By Jeffery S. Thompson, Harry Hinds

Recent advances in the development and application of the DuPont Activator Technology are discussed. Activators are catalysts of gold dissolution in cyanide solution. Plant testing of this technology in the vat leach circuit of the Homestake mine in Lead, South Dakota, showed increased gold recoveries ofup to 5%. Homestake has licensed the technology for this application and is in the process of full commercialization. Results from testing additional ores on a laboratory scale are also presented. These results indicate this technology will also increase leaching at much lower cyanide concentrations while achieving the same gold recovery.

Jan 1, 1997

The bromine review did not arrive in time for publication in the June issue. Bromine production in the United States during 1992 amounted to 171 kt (376 million lbs), a 453-t (I-million lb) increase from 1991. Data compiled by the US Bureau of Mines indicates this increase was due mainly to greater exports of elemental bromine and bromine derivatives (flame retardants). Exports increased despite the economic slowdown in Europe and Japan. The United States remains the world's largest bromine producer, with about 42% of the total. Israel is ranked second, followed by the United Kingdom, the former Soviet Union and Japan.

Jan 1, 1993

By H. Nematollahi

Numerous magnesite deposits are found in the south part of Khorasan state, east of Iran. During the past few years, production of high-grade magnesite ore was possible only by using selective mining method. The decreases of high-grade ore imply upgrading of the low-grade ore. To do so, the objective for the first phase is to obtain a material which contains less than 2.5% SiO2. The present study was carried out based on three different samples. The results obtained in laboratory indicate that the direct flotation of magnesite by fatty acids led to acceptable result.

Jan 1, 2003

By R. Hiebert, M. Foote, S. Nordwick, M. Canty

An innovative biological treatment system designed to detoxify cyanide and nitrate and immobilize metals from cyanide leach operations is described. A pilot-plant demonstration was conducted to detoxify cyanide and immobilize several metals from a process stream at the McCoy/Cove Mine. Testing was performed under the EPA’s Mine Waste Technology and Superfund Innovative Technology Evaluation Demonstration Programs. This technology was successful in detoxifying cyanide and effective in removing metals. The pH was consistently neutralized and nitrates were successfully removed. Results show that biological treatment can offer an innovative, cost-effective alternative for the treatment of mining wastewaters.

Jan 1, 1999

By A. D. Davis, D. J. Dixon, J. L. Sorenson, C. J. Webb, S. Dawadi

Limestone-based material appears to be an effective arsenic removal process that has great potential for source reduction in drinking water. Limestone-based material offers several benefits to the drinking water community: 1) reasonable removal efficiency as compared to material cost, 2) broad geographic and water system applicability, 3) compatibility with other water treatment processes, 4) ease of technical use, and 5) low-cost disposal in ordinary landfills. Batch and column experiments have evaluated the removal efficiency of several limestone types. Additives and material alteration have increased the removal efficiency. Granulation of powdered limestone as a filter media currently is being investigated.

Jan 1, 2006

By J. L. Marchese

Belt conveyors face their applications life with a promise of constant abuse: heavy and rough products cascade onto the belting without let-up; caustic and abrasive materials such as salt and ore eat away at the cover; high temperatures, even open flame at times, sear and soften belting materials; and unyielding tension stretches and strains every belting component. The only defense against the applications onslaught is to follow the basic rules of proper handling, installation, and maintenance. Under the direction of qualified personnel (one responsible person, if possible), you can insure that conveyor belting begins operation in top condition.

Jan 6, 1980

By Debbie Nakamura, Daniel Tempelis, John E. Shamma

The Metropolitan Water District of Southern California established a Board of Consultants to assist them in administering the design and construction of the Inland Feeder Program tunnels. The Board acts as an expert review body for the owner, looking at key issues that can potentially impact the success of the program. The use of the Board evolved over the life of the project, and its composition was modified to better address the needs of the owner, and the Program requirements. The experience, function, and value of such a board is analyzed and discussed in this paper.

Jan 1, 2003