Search Documents

By Gordon F. Revey, Dan Harrison

Hanging Lake Joint Venture recently excavated two conventional 12.8 m (42 foot) diameter highway tunnels in the difficult ground conditions of Glenwood Canyon, Colorado. This paper outlines the type and success of the various Controlled Blasting Techniques that were used to minimize overbreak in the portal and tunnel excavations. The different Smoothwall and Cushion Charge loads used in the different ground types are described in detail. Delay Timing and Drilling Pattern variations are also discussed.

Jan 1, 1991

By A. F. Raschenko, V. V. Elschin, Y. E. Golodnov

Kinetics and mechanism of gold and silver sorption from thiocarbamide solutions by activated carbon were studies using tne method of equilibrium-kinetic analysis. The intradiffusonal character of the process was determined and the kinetic and thermodynamic constants were calculated. The electrostatic component of the adsorption interaction was estimated by the electro - chemical investigations. The optimal parameters of the desorption of noble metals thiocarbamide complexes were determined. The intensification of gold and silver desorption process is reached through the use of activating additions to the eluent and electro - chemical polarization of activated carbon. Methods for complex and selective extractions of gold and silver from thiocarbamide solutions and pulps by activated carbons were developed.

Jan 1, 1995

By P. C. O. Chukabarah

Atkinson's resistance square law is the cornerstone equation for traditional expression of energy losses in mine ventilation engineering. But the nomenclature for the various forms of energy losses are often confused for one another, misapplied or misinterpreted. These forms of energy were re-examined from thermodynamic and fluid-dynamic perspectives. Resultant expressions showed that both incompressible and compressible flow regimes in underground mines can easily be accommodated. Given the well-known three major energy forms, which are equivalent to one another but numerically unequal, corresponding equations to Atkinson's (pressure loss) for headloss and workloss were derived. The thermodynamic weight relational resistance ([w] s2/m5) associated with energy per unit weight (headloss) was dimensionalized for the first time. Also, normalized Atkinson-like equations for headlosses and worklosses were derived to ease direct computations in mine ventilation practice.

Jan 1, 1995

By D. L. Schweyer, W. A. Munson, R. H. Hanewald

Discussed is the INMETCO processing of electric arc furnace (EAF) baghouse dusts from the specialty-steel and low-alloy industries. In addition, the INMETCO process has been modified to recover nickel, chromium and iron from many other waste materials including: •pickling solutions or filter cakes, •spent nickel and chromium plating baths, •carbon refractories from pickling tanks, and •superalloy wastes including baghouse bags. INMETCO is the only North American company presently capable of recycling nickel-cadmium batteries by high-temperature metals recovery. This process and the details of INMETCO's best demonstrated available technology (BDAT) test program are discussed.

Jan 1, 1993

By Robert T. Beckman

Education of inspection and operating personnel is essential to protection from radiation hazards in the mining industry. For over 10 years, MSHA has presented the only formal course on radiation measurements and control available to the mining community. Course objectives and content are described in this paper.

Jan 1, 1981

By Georgy Cherkashov

The geological setting, morphology and physical properties of massive sulfide deposits must be taken into account when designing the underwater systems being currently constructed for mining of this type of marine minerals. Based on more than 20 years experience of hydrothermal mineralization studies in the northern equatorial part of the Mid Atlantic Ridge (MAR) we have provided the following conclusions:

Jan 1, 2008

By S. El-Mofty, P. Zhang, N. A. Khalek

This article reviews different technologies used for beneficiation of siliceous and calcareous phosphate ores of different origin. The review sheds light on recent trends suggested for solving problems associated with separation of different impurities from phosphates. Applications of recently modified flowsheets as well as new reagents in the flotation of phosphate ores of sedimentary origin are highlighted.

Jan 1, 2003

By William F. Riggs

In the fresh application of a frother, collector, or the change of any particular reagent, the interaction caused by this change is often overlooked since we attempt to solve a problem or improve a situation with use of a particular reagent without regard for the Interactions or side effects. When a particular reagent is added to a flotation circuit or substituted for another reagent, a series of chemical reactions occurs which. In turn, will create different physical responses. This discussion will provide a series of examples which have actually been experienced by the author.

Jan 1, 1994

By R. L. Grayson

As a followup to a USBM-sponsored research project, the authors utilized the knowledge-base structure and system concepts from a Sun Sparcstation-based worker-scheduling system of the mine-management support system to develop a PC-based application. The new software adopts the nested-window concept to facilitate data collection and modification on personnel, including their availability and work priorities during a shift. The system can optimally allocate manpower on a work shift and can delineate supervisory training responsibilities. The various components of the software, including enhancements made to the original system, are described in detail.

Jan 1, 1997

By E. Varouchakis

Spartan Spatial Random Fields (SSRF?s) provide a new geostatistical framework (Hristopulos, 2003) with applications targeting environmental risk assessment and natural resources estimation. SSRF?s have the ability to incorporate constraints based on physical laws in the statistical description and have proved to be computationally fast in the analysis of synthetic data sets. This paper presents an application of a specific SSRF model and a new local-error spatial estimator (Hristopulos, 2005) in the mapping of environmental pollutants using a real data set. A detailed comparison of the local SSRF estimator with a classical kriging method is presented. It is shown that the SSRF approach provides a competitive alternative for spatial estimation.

Jan 1, 2005

By R. K. Amankwah, E. K. Asiam

Changes in the thermal-oxidation behavior and other properties of gold-bearing waste activated carbon when milled in both a ball mill and a vibratory mill were investigated. It was found that significant changes occurred in the oxidation temperature of the vibration-milled waste carbon as a result of increases in surface area and mechano-chemical activation. The mechano-chemical action brought about modifications in the crystal structure of the waste carbon. As a result, the vibration-milled sample was completely oxidized at a temperature of 450°C. Thus, the study established that vibration milling is a better way of lowering the temperature of oxidation of the waste carbon. Furthermore, the gold was found to be concentrated in the ash and, when leached with cyanide for 20 hrs, the gold recoveries from a sample having a head grade of 2 kg/t was 99.5% for the vibration-milled sample and 82% for the ball-milled sample. The lower gold recovery for the ball-milled sample was attributed to sintering of the ash, which was caused by the higher temperature required for its oxidation.

Jan 1, 1997

By John V. Beall

A completed feasibility study executed by an independent agency can benefit a company in two ways. Inside the organization, it verifies the project staffs ideas and their concept of the facility. Outside the company, it can be utilized to obtain equity partners, debt financing, and other forms of credit. It is advisable to bring in a project execution contractor for the feasibility study. A project execution contractor is able to work with engineers to develop the project concept, process flowsheet, and best utilization of the site. By getting an early start on understanding a company's policies and working methods, a project execution contractor saves the company money since it does not have to go through the educational buildup twice. The contractor is a specialist in putting together a bankable document that can be taken to a financing source. It answers all the agency requirements on the first pass. In addition, the contractor can advise an owner on likely financing sources since he works on the worldwide market every day. A less obvious advantage of including the contractor in the study and predevelopment buildup stages is the importance of coordinating finance and technical input. The financing source influences equipment specifications, procurement, logistics, project schedule, cash flow, and liquidity. There are many surprises in store for any manager of a large international project involving worldwide financing and purchasing. The job does not have to be made more difficult by bringing in a contractor after all predevelopment steps are taken. The contractor can still work if the predevelopment steps have been done, even if he does not agree with them. But early contractor involvement is the preferable solution.

Jan 10, 1980

By Steve Vaughan

Canadian Regulation and Reporting Requirements High reporting standards are essential in developing and sustaining a strong confident capital market. As of February 1, 2001, technical reports on mineral exploration and mining work, must conform to the standards of the Canadian Securities Administrators (CSA) National Instrument 43-101. Only a ‘qualified person’ may supply the technical information on which a news release is based and must verify that the final version of the release is accurate.

Jan 1, 2003

By Simon Wright, Roland Heersink

In the past, the center of most companies' e-initiatives has been on reduction of indirect costs, such as selling and procurement. Recently, e-commerce has moved its attention from back-office functions into manufacturing, in order to significantly reduce direct operating costs. This paper describes many of the Web-Powered Manufacturing initiatives being employed across various industries, and relates them to similar opportunities being started within the mining and mineral-processing sector. The following opportunities are enabled by Web-Powered Manufacturing: • Collaboration with outside experts to extend their pool of resources • Management of remote and distributed operations • Tie-in of small operations to a larger operation • Monitoring a position in a JV operated by a partner • Managing a plant located in someone else's facility • Having a chemical supplier manage his inventory in a customer's tanks • Having an equipment supplier remotely troubleshoot his equipment installed in a customer's site • Having an additive supplier provide remote pro-active. guidance in optimization of a customer's operation • Having software suppliers take responsibility for the results of their applications • Outsourcing software and systems support by providing remote access Details of one of these opportunities are described in this article, and the benefits captured using this approach and the technologies necessary to make them a reality are emphasized.

Jan 1, 2002

By Mark J. Dowiak, Daniel Threlfall

The disposal of hazardous chemical wastes will be one of the major environmental issues of the 1980s. About 45 Mt of hazardous wastes are produced yearly. One major aspect of the problem is the siting, design, and construction of' environmentally acceptable disposal facilities to accommodate this huge volume of material. Surface mines have been considered attractive for development as disposal sites for several reasons. • Surface mines offer an open pit that can conveniently serve as a repository for wastes. This could represent a significant economic, savings when compared with sites on undisturbed lands that might require extensive excavation or embankment construction. • Surface mines often have an abundance of mine spoil available that could potentially serve as construction material. This could result in a significant economic advantage over other sites that might require extensive amounts of construction material to be excavated or hauled in. • Operation of a commercial disposal facility in a surface mine can reduce or totally alleviate reclamation costs. • For an abandoned surface mine, conversion into a disposal facility could represent a positive form of land use and may provide a means for reclaiming lands that would otherwise remain unreclaimed. Despite these positive reasons, there are many technical factors associated with surface raining that can make the prospect of disposal site development an uncertain one. Before discussing factors associated with mining that can present siting, design, or construction problems, some understanding of the basic components of a chemical waste disposal facility is necessary.

Jan 2, 1981

By A. K. Mukhopadhyay

[The mechanical status of a mine ventilation fan can be monitored effectively through vibration analysis. An expert system can be an effective tool in fault diagnosis for a variety of equipment. Computers have made it possible to implement an expert system to analyze the data for correct and appropriate diagnosis. In addition, vibration analysis can provide important information oil the condition of the machine. This paper discusses an approach for an expert system to determine on vibration analysis, practical problems that can occur with a fan. The frequency of the vibration is the only characteristics considered in the analysis, although other variables are discussed in the paper. Finally, a simple computer program, written in Turbo Prolog, is presented. A friendly query system, menu operation and a disk-resident separate knowledge base are a few of the salient features of this system.]

Jan 1, 1997

By V. Carabias-Hütter, A. J. Basu

The paper aims at promoting sustainability assessment and reporting into practice using a globally acceptable set of guidelines and a common framework for internal and external reporting at a project/site level. Indicators are used for measuring performance, and this paper addresses development and implementation of performance indicators for sustainability assessment and reporting at local as well as global levels. The selection of a proper set of indicators is a challenging task. The indicators selected should provide the expected information for making right decisions. Relevant and credible sustainability reporting supported by a consistent performance indicator system can be the starting point for benchmarking environmental and social performance for the natural resources sector.

Jan 1, 2004

By Jack G. Pippenger

The Coteau Properties Co.'s Freedom mine is a surface operation near Beulah, ND that produces more than 13.6 Mt/a (15 million stpy) of lignite. Coteau, a subsidiary of North American Coal Corp., ranks among the largest mines in North America. In 1994, Coteau ranked eighth in annual coal sales, becoming the largest mine outside the Powder River Basin of northeastern Wyoming. However, for the Freedom mine to stand alongside the Powder River Basin heavyweights, Coteau had to overcome several obstacles. These included a coal seam with three-quarters the heating value and overburden-to-coal ratios three times higher than Powder River Basin mines. Coteau's ability to compete has been built around a program of continuous improvements in productivity, cost efficiency and innovation.

Jan 1, 1995

By Jaye Pickarts, Bret Boster, Jack McPartland

Pegasus Minera de Chile, Ltda. is completing three phases of metallurgical evaluation on the Pullalli project to develop a preliminary process flowsheet. A project feasibility study is in progress. The feasibility study includes a proposed process flowsheet designed based on results from the multiple stages of metallurgical evaluation. Phases I and II of metallurgical evaluation included laboratory scale heap leach and milling cyanidation testwork on multiple drill core composites and bulk ore samples from the Pullalli Project. Phase Ill included pilot scale milling/cyanidation testwork on Pullalli drill core composites. The proposed flowsheet includes selective mining and separate processing of low grade and high grade ores. Low grade ore will be crushed and heap leached. High grade ore will be milled leached for 12 hours in an agitated cyanidation circuit. After 12 hours of leaching, sands and slimes will be separated and the sands will be washed using a counter current cyclone (CCC) circuit. Partially leached and washed sands will be added to the crushed low grade ore for heap leaching treatment and permanent placement. Partially leached slimes will be thickened in a high capacity thickener and will be processed in a CIP circuit. Leached slimes will be placed in a tailings impoundment.

Jan 1, 1996

By A. H. Morris, W. Harrison

1. INTRODUCTION Roadheaders have a shadowy origin - probably in Eastern Europe - but were introduced to Europe and the West by the importation of a Russian PK3 machine by the National Coal Board in 1961. A number of features rendered this type of machine an attractive tool for coal mine operators: its flexibility of operation, its combined cutting and loading ability, the opportunity it provided of making any shape of roadway, as well as its ability to cut some rocks. Encouraged and sponsored by the National Coal Board, the development of roadheaders was taken up in Great Britain, notably by Anderson Strathclyde and Dosco; in Europe, predominantly in numerical terms by Voest Alpine and Paurat. Over the 24 years since the importation of the first PK3, evolutionary development has taken place to the extent that machines are now available in many forms up to 120 tons in weight. Machine design has altered, partly as a result of increased power requirements and partly in line with the use of a ripping or a co-axial head. However, the basic concept remains: a boom containing a motor and transmission gear, with a driven cutting head at its extremity and capable of universal movement urged by hydraulic rams mounted on the boom turret and on the machine deck. Generally, the turret, hydraulic powerpack and all other necessary equipment are mounted on a chassis, which contains a discharge conveyor, the whole being carried on caterpillar tracks so that a complete machine entity is provided. Figure 1 shows how the weight, power and - non-proportionally - the cutting ability of machines have increased over the years. From

Jan 1, 1985