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By Misra M., P. Grimes, Chen. S.

The combustion of petroleum products produces emissions which contain oxides of nitrogen (NOx), hydrocarbons (HC), and particulate matter (PM) which have adverse health and environmental effects. In recent years there has been increasing interest in the use of water-fie1 emulsions as a substitute for conventional fuels. Emulsified fuels are emulsions of water in fuel, which are typically made of 10 to 20 percent of water mired with certain additives and fuel. Studies have shown that the emulsified diesel can significantly reduce the emissions of NO, PM and car- bon monoxide and increase the fuel efficiency. In order to produce a stable diesel emulsion, the development of an effective surfactant additive is critical. The stability of diesel emulsions is influenced by many factors, including size distribution of the droplets, the viscosity of the continuous phase, the physical properties of the interfacial film, and temperature. This paper describes a method to produce emulsified diesel and combustion results obtained from various tests. It has been found that the diesel emulsion made with this additive package was stable during the test, and the emissions were lower in NO, CO, and PM compared to the baseline diesel.

Jan 1, 2005

By John E. Urbanic, William D. Faulkner, Robert W. Ruckel

Guidelines are presented for the selection, handling and regeneration of activated carbon used in gold recovery operations. The guidelines are based on Calgon Carbon Corporation's own investigations and experience gained in working with gold mine operators all over the world. Gold adsorption rate and adsorption capacity are shown to be independent variables thereby requiring testing of both properties when selecting activated carbon. Means of measuring these properties are provided. Historical activity tests on activated carbon are shown to be minimally useful in selecting carbon for gold recovery. Proper thermal regeneration techniques to maximize recovery of adsorption rate without weakening the carbon structure are suggested. Simple positive means of measuring efficiency of regeneration are presented. The subject of hardness measurement as a predictor of "in process" abrasion is discussed. The cost/benefit issue of carbon activity level is addressed.

Jan 1, 1986

By P. Tsang, S. S. Peng

Mine floor failures, such as floor heave and floor buckling, occur frequently in underground coal mines where soft mine floor exists. The types of failure can usually be classified into two categories; shear punching failure and tensile failure. A model based on the Winkler's elastic foundation is proposed in this paper for floor stability analysis. The model considers material properties of floor strata, in-situ horizontal stress, pillar size, entry width, and configuration of multiple-entry system and predicts stress conditions in the mine floor based on given in-situ mining and geological conditions, as well as deformation of the mine floor. This information is used to predict possible failures of mine floor by comparing the strength of mine floor with its stress condition. The validity of the model is verified by in-situ data described in this paper.

Jan 1, 1992

By David J. Starbuck

For small precious metals mining to show a comeback a different perspective must be taken than that of larger mining companies. This perspective must be much the same as that of past successful smaller mining enterprises such as when the US had a need for Uranium. Abandoned mines and environmental concerns in older mining districts have discouraged many from entering with the attitudes of why try there if so many unsuccessful mines exist. A small mining venture can be successful there but must have a "think smart'' attitude. There must be a thorough understanding of deposits, utilization of advanced technology and a properly managed mining operation. "THINK SMART" MINING The small mine operator is usually looking for small high grade deposits, consequently, long term success depends on a series of small successful mining operations. The small miner must succeed right-off or credibility and future project funding will suffer. No veteran of even a few years in the mining industry needs to be told that a dollar spent on production today fails to yield as much as it once did. More efficient equipment and techniques have helped soften the problem, but there is little likelihood that a mining company can do much to control inflation, wages, regulations, or grade. That leaves the small miner to "think smart" as one area where operating dollars can still be stretched to produce more than they presently do (Gardner. 1981). In the planning stage of a mining venture, when most options are still open, the main controllable elements are market timing, deposit selection, cutoff grade, mining method, mine design, mining sequence, rate of production build up, process design, project financing structure, project management, and project ownership structure. During planning, optimum criteria can be established for each of these. Once a mine is in production, these options are foreclosed or at least severely constrained. The more thought given to a mining program using all information available the less the risk of encountering disabling surprises. Thus the intent of this paper is to suggest the "think smart" attitude most small mine operations use for long term success. If one looks at a number of successful mining ventures, whether large or small, there is a general logic most have followed to be successful. They have used proven exploration, mining and processing techniques along with economic evaluation and experienced personnel to improve their odds. LOGIC IN DEVELOPING A FEASIBLE VENTURE Most successful small mine ventures achieve positive cash flow as quickly as possible by seeking out those deposits which require the least time and expense on activities leading up to production. To do this they look for deposits that are the most accessible, easily investigated, mined and processed with the cheapest fundamental methods. The general sequence of events starting with district selection are deposit selection, preliminary feasibility, exploration, detailed economic feasibility, mine planning, development and production. Each successive step becomes more costly requiring intermediate decisions along the way. District Selection Small operations should look for known deposits which favor the occurrence of the type deposit sought rather than efforts in unproductive areas. Known deposits in developed areas have some advantages over remote areas: 1. More alternative methods of transportation are available. 2. A larger stable work force is available. 3. The area is usually more pro-mining. 4. Power, water, housing, technical services, skilled services, schools, recreation and shopping are available.

Jan 1, 1987

By M. K. Gangal, E. D. Dainty

CANMET/MRL has been contributing to an industry/government program to assess the quality of air in mines, and improve the working environment for Canadian miners. The ultimate aim of this program is to recommend a sampling methodology and appropriate concentration limits for both the soot (diesel particulate matter - DPM) generated by diesel equipment, and respirable combustible dust (RCD) as measured underground. The program was conceived by the Canadian Adhoc Diesel Committee, which consists of representatives from seven major Canadian mining companies, three provincial inspectorates, one union representative, two manufacturers of diesel equipment, and CANMET, a Federal Canadian research agency. This paper describes the modification and laboratory confirmation of an existing methodology for the sampling and analysis of DPM/RCD, including: sampling problems, filter selection, filter efficiency, DPM size distribution, the approximate performance of fractionating devices, and it reports the results of current ambient measurements of exposure levels in Canadian underground mines. Because of the concern about the health impact of DPM/RCD on mine workers, North American agencies are in the process of establishing limits for these aerosols. So far, the Province of British Columbia is the only jurisdiction in North America to legislate the maximum exposure level of RCD in its underground mines, i.e. 1.5 mg/m3 interim level recommended by the Adhoc Diesel Committee. It has also recommended the use of the CANMET/ADHOC RCD sampling protocol.

Jan 1, 1993

By D. S. Cavers

INTRODUCTION This paper discusses aspects of rock engineering applicable to surface gold mines. Discussion particularly centers on areas in which rock mechanics can enhance the mine productivity or profit- ability. Methods of analysis are discussed briefly but for more detai1s the reader is referred to the appropriate references. A team approach to the overall design of the pit generally pro- duces a better result at an overall lower cost. In particular, money is wasted by asking for a "report on slopes" and then input- ting this slope angle into a pit design and economic analysis study without further reference to the geotechnical engineer. Pit slope angle depends on slope orientation, location, pit shape, pre-existing discontinuities and mining methods. Preliminary slope angles can be produced but optimization depends on ongoing inter- action between the mining engineers, geologists and geotechnical engineers. This interaction can a1 so substantially reduce overall design time which may be critical in bringing remote plays into production. Most surface gold mines in North America are in igneous or metamorphic environments. Rock mechanics aspects discussed in this paper will be discussed with reference to these environments al- though most of the principles and comments are applicable to sedimentary environments as we1 1.

Jan 1, 1987

By J. J. Kollé

A compressed-water hydraulic pulse generator (HPG) for nonexplosive blasting of rock and concrete is described. Energy is stored in the HPG by compressing water to ultrahigh pressure. A large, fast-opening valve discharges the compressed water, resulting in a high-energy impulse. The HPG can be used for small-scale bench blasting by discharging the water through a nozzle that is closely fitted into a borehole. A bench blasting system requires an HPG, a drill and an indexing mechanism to allow insertion of the HPG nozzle into a drilled borehole. Systems with discharge energies ranging from 40 to 250 kJ have been used to excavate hard rock, including andesite, granite and quartzite. The largest system can excavate 15 t/h (16.5 stph) of massive quartzite based on a 2-min cycle time for hole drilling. Blasting with an ultrahigh -pressure hydraulic pulse generator was demonstrated as an effective means of excavating hard, massive rock under the confined conditions of a tunnel opening or underground sloping panel. Hydraulic blasting provides a continuous mechanized mining capability that is well suited for deep-level mining and urban excavation sites where explosives are prohibited.

Jan 1, 1998

By J. J. Wallaert

The decreasing supplies of natural gas and low-sulfur crude oil available for electric power generation in the United States will unquestionably shift the emphasis to nuclear and coal fired steam power plants in the immediate future. Failure to do so will ensure our dependence on mid-east low sulfur crude oil comprising some 70% of the known world reserves, and imported liquid natural gas. By contrast, the United States has 43% of the known world reserves of anthracite, bituminous and semi-bituminous coal and 48% of all known coal reserves of the world including lignite. It is evident, therefore, that coal is alive and well and will continue to be a significant energy source for the production of electricity for many years. Of course, concern for our environment and the development of new technologies will ultimately curtail the utilization of coal for the generation of bulk power, but information released by the National Electric Reliability Council and the Federal Power Commission is worth repeating. In the year 1972 the total capacity of generating units in the United States was 379,552 Mw of which 149,974 Mw, or 39.5% of the total, was produced by coal fired steam turbines which consumed 344,700,000 tons of coal. New capacity additions planned or in construction show that in the year 1981 our total generating capacity will be 843,503 Mw, of which 257,995 Mw, or 30.6% of the total, if from coal only. Translating this increase into terms meaningful to the bulk material handling industry suggests that ten years from now the utility industry will require 590,000,000 tons of coal per year - a monumental task - if we are to sustain our current demand rate for power.

Jan 1, 1973

By Peter J. Suardini

Over the last few years, researcher have been working on improving procedures for fine-coal (minus 150 microns) washability analyses. The effort was stimulated by past difficulties in obtaining accurate and reproducible results from the various commercial laboratories providing fined washability services. This paper contains the results from fine-coal washability testing, performed by Process Technology, Inc. (PTI), as part of a U.S. Department of Energy (DOE)-sponsored project. The testing focused on comparing the performance of a number of media options (i.e., aqueous solutions and organic solvents), as well as evaluating the impact of a number of procedural steps on separation performance. The paper summarizes PTI's recommended washability procedures for various size fractions and ranks of coal, and makes recommendations for future studies of certain phenomenon, such as void penetration and particle density changes, which are not well understood.

Jan 1, 1995

By C. E. Jordan

The Bureau of Mines has investigated the fundamentals of fatty acid/fuel oil conditioning for improved flotation selectivity. Both conditioning time and intensity can provide optimum flotation selectivity as well as good recovery. Traditional conditioning seeks to optimize conditioning parameters with subsequent recovery of the hydrophobic mineral. In the fatty acid/fuel oil system many silica gangue particles are also rendered hydrophobic by the flotation collector. Fundamental studies have shown that particle-particle collisions transfer the collector reagents selectively to the mineral surfaces with the highest affinity for the reagent. This mechanism deactivates the gangue particles while increasing the collector reagent loading on the selected mineral. The degree of this transformation is directly related to the number of particle-particle collisions which can be controlled through conditioning time or conditioning mixing intensity.

Jan 1, 1995

By S. G. Axen

Design of wells for in-situ leaching is based on individual mining operation and ore deposit requirements. Major design considerations are well flowrate, depth, fluid composition, expected well life, mine operating plan and cost. A large variety of downhole equipment, materials of construction, contract services and methods of well completion and stimulation are available. A generalized design procedure which allows the engineer to optimize well design for a particular ISL application is described.

Jan 1, 1988

By G. E. Burrer, D. Malhotra, T. E. Irwin, S. Johnson

Climax byproduct-plant tailing assayed 0.019% WO3. Pilot-plant and laboratory tests were performed to investigate the possibility of recovering additional tungsten values from the byproduct-plant tailing. The methodology used in the study and the results of this investigation are discussed.

Jan 1, 1987

By Giuseppe Bonifazi

This study examines the problems involved with the control of characteristics of the products resulting from comminution operations. A methodology of investigation based on texture analysis procedures by image processing techniques of the comminution product is proposed. Some examples of applications are considered with particular reference to comminution products of different textural, structural and mechanical characteristics. The advantages and the limites of this method of approach are, indicated, both as regards performance of the investigations and subsequent processing of results.

Jan 1, 1989

By E. J. Donovan, O&apos

The use of Dynamic Analysis techniques in the design of conveyor systems is extremely limited. The most frequent use of the technique is in large and expensive systems where the emphasis is on insurance against failure caused by catastrophic tension waves. This paper sets out to illustrate a much wider range of applications where dynamic analysis has been successfully employed. The examples chosen deal with identification and correction of dynamic low tension problems, the variability in take-up movement as other system parameters change, the requirement for proper tuning of starting controls and finally the absolute necessity for a complete understanding of the entire system when specifying brakes for critical applications. The intent of the paper is to get designers to view a conveyor as a system of interacting flexible components rather than as a single rigid body.

Jan 1, 1993

By Chris Laughton, Bernhard Spoerr

"Tunnel inspections are increasingly needed to ensure that aging infrastructure does not fail in service. To this end the time between inspections is being reduced, the thoroughness of each inspection is being increased to provide for a more detailed assessment of conditions and inventory defects. The conventional Tunnel Report, containing hand-drawn maps and/or photos, and a log describing observed defects and areas of deterioration, is being increasingly replaced by LiDAR generated 3-D surface maps. The data collection process that traditionally supports development of a Tunnel Report is labor-intensive, taking crew-days of engineering effort, and requires partial or full stoppage of tunnel operations. In an urban setting, such multi-day interruptions in service are difficult to countenance for a near-capacity tunnel operation. Under time pressures, the detail and accuracy of the manual inspection process will inevitably be compromised, resulting in a high cost, low quality product. As the tunnel inspection window decreases the argument for incorporating laser scanning in to the inspection process is increased dramatically... The 3D scan technology allows detailed and accurate data to be collected within the tight time frames demanded by the owners and operators of critical infrastructure. Not only does the use of laser scanners improve the 3D accuracy of the data collected, it also, enhances the efficiency and safety of the inspection process, reduces data collection and processing costs and enhances the reliability of results over time. The paper will also demonstrate the value of adding photogrammetric data to the 3D Model to show surface defect discoloration. The accurate and detailed data collected by a combination of LiDAR and photogrammetric techniques provide superior data needed to inform critical asset management decisions related to maintenance, repair and replacement."

Jan 1, 2016

By Andrew Torok

Activated bleaching clays, so called because of their ability to remove color bodies from bleach fats and oils, are produced from clays of bentonitic origin. Activation is achieved by subjecting these clays to physical or chemical alteration to increase selective sorption capacities (1) . The future of activated bleaching clays depends upon the ability of producers to recognize the new areas of applications which are arising, and their skill in developing sophisticated active clays to meet new and stringent requirements. The major portion of activated bentonites are produced for decolorization of oils. New techniques of activation will improve these clays for broader spectrum use. General properties expected to result from present activation methods are: 1. Modification of hydrophobic-hydrophilic properties and increased available surface area in non-aqueous systems, thereby improving sorption capacity and ability to remove color bodies from oils. The following additional properties will be expected from future activated clays: 2. High purity of the active clay with interfering impurities totally removed. 3. Increased selective sorption capacity in aqueous systems. 4. Selective chemical reactivity, such as oxidation or hydrolysis. This property is required for removing

Jan 1, 1971

"INTRODUCTION While the United States coal mining uses prescriptive regulation under the Title 30 Code of Federal Regulation enforced by the Mine Safety and Health Administration (MSHA), Australia uses a risk based approach. Australian regulation is individual to each state. In Queensland, Australia this risk based approach to address principal hazards is underwritten by the Queensland Coal Mining Safety and Health Act of 1999 and the Coal Mining Safety and Health Regulation of 2001. Each Queensland Mine is required to have an overarching Health Safety and Environment Management System, of which Safety Management Plans are an element. “Safety Management plans (SMP’s) are intended to formalise the process by which mines address principal hazards and other related matters to ensure the safety of mine personnel.”7 THE QUEENSLAND CONTEXT In Queensland, the basic elements of a coal mine’s safety and health management system must provide for risk identification and assessment, hazard analysis, hazard management and control, and the reporting and recording of relevant safety and health information and data.5 (Part 2 Division 1 Section 6(a-d)) The initial guidance for writing Safety Management Plans comes from the Approved Standard for Mine Safety Management Plans and Guidance Note QGN09- Reviewing the Effectiveness of Safety and Health Management Systems. The Guidance Note and Approved Standard are supplemental to the Act and Regulation, and put in place to provide more clarity around the topic. The definitions in this section come from the Approved Standard and are included to provide context for those who may not be familiar with Australian or Queensland law and regulation. A hazard is defined as a source of potential harm or a situation with a potential to cause loss, while a principal hazard is a hazard with a potential to cause multiple fatalities. A risk is the chance of something happening that will have an impact upon objectives which is measured in terms of consequences and likelihoods. It is important to be able to make the distinction between a hazard and a risk. For instance, a lion is a hazard, while the risk associated with a lion is getting eaten. As defined by the Queensland Approved Standard for Mine Safety Management Plans, a Safety Management Plan (SMP) requires a systematic definition of all the actions necessary to ensure that mining operations are carried out safely. A SMP includes, but is not limited to organisational structures, planning, activities, responsibilities, practices, risk identification, audits and reviews.7 The goal of a SMP management plans is to mitigate the risks to bring them to an As Low As Reasonably Achievable (ALARA) level."

Jan 1, 2016

By T. H. Dubaniewicz, J. E. Chilton

The U. S. Bureau of Mines is investigating the application of fiber optic technology to methane and carbon monoxide monitoring. A methane monitoring system is described that is based on differential absorption of infrared light. It can detect concentrations as low as 0.2% and as far away as 2 km via fiber optic cable. The upper range is 100% methane. The system requires no electrical power within the mine so it should operate safely under mine disaster conditions. A hybrid carbon monoxide monitoring system is described that combines a low-powered electrochemical cell with fiber optic telemetry. Testing has shown the system can operate maintenance- free for several months.

Jan 1, 1992

By B. Denby, R. Hollands, S. Cooper

Augmented Reality (AR) is a technology that can be used to mix computer-generated images of data with views of the real world. The University of Nottingham is developing AR technology in a major research project which can be used to assist mining companies in visualising complex mine data whilst out in the field. The technology comprises of integrated GPS surveying technology and electronic orientation devices to provide location and viewing information, video capture via digital camera and portable computing hardware to overlay 3D models on views of the real world. The paper describes the concepts of the technology in some detail and concentrates on the possible applications of this in the surface mining and exploration industries.

Jan 1, 2002

By A. Geoffrion, L. J. Cousineau

In underground powerhouse excavations, the access to the horizontal sections of the penstocks is most often critical. Other factors which influence the schedule include: the sequences of excavation, the interface dates between contracts, the type of support for the overhead cranes and whether the roof in the powerhouse is a reinforced concrete arch or a suspended prefabricated material. At Outardes 3, Churchill Falls and LG-2, these factors, along with the size of the powerhouse and the local topgraphy and geology were studied to produce the optimum schedule.

Jan 1, 1983