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By Jurgen H. Kleinau

This paper details Keeler/ Dorr-Oliver's experience with the application of fluid bed combustion technology to the burning of coal-mining waste. The designs of two stage fluid bed combustors/dryers are demonstrated as useful in the drying of coal, slag and coke, using coal and coal refuse (gob) as fuel. Anthracite mining refuse (culm) is more than abundant in Northeastern Pennsylvania. After demonstration at Shamokin, Pennsylvania, a full commercial-sized fluid bed boiler using culm is used for district heating in Wilkes-Barre, Pennsylvania. Limited research work has shown the utility of using fine coal as filter aid in sludge in¬cineration. With the rising avenues of the suitability of coal as auxiliary fuel in fluid bed sludge incineration, an expansion of these concepts combines the use of coal or coal refuse as filter aid and auxiliary fuel. Lime¬stone addition controls SO2 emission.

Jan 1, 1985

By P A. Lang, J G. Ayotte, R W. Humphries

Atomic Energy of Canada Limited (AECL) has the responsibility for research, and development of technologies, for the safe and permanent disposal of Canada's nuclear fuel wastes. As part of this comprehensive program, AECL is constructing an Underground Research Laboratory (URL) near Lac du Bonnet, Manitoba, to evaluate aspects of the concept of waste disposal deep in stable geological formations. No nuclear wastes will be used in the URL program.

Jan 1, 1986

By Margaret E. Egan

Reliable fire detection is essential for both safe evacuation and containment or extinguishment. In order to increase reliability by reducing the number of nuisance fire alarms in underground mines that use diesel-powered equipment, the U.S. Bureau of Mines has developed a diesel-discriminating fire detector (DDD). It was designed to discriminate between smoke produced by a fire and the smoke-laden exhaust of a diesel engine. Experiments were conducted by the Bureau to compare the smoke detection capabilities of the DDD with those of conventional fire detectors in response to smoldering coal and conveyor belting. A comparison was made among the alarm times of a carbon monoxide (CO) detector with an alarm threshold of 5 ppm, a smoke detector with an optical density alarm threshold of 0.044 of', and the DDD with an alarm threshold of 0.025 V. The results show that the DDD will reliably detect developing coal and conveyor belt fires. The average time delay separating the DDD alarm from the first detector to alarm was 76 s for smoldering conveyor belt and 65 s for smoldering coal. The longest time delay between the response of the DDD and the first detector to alarm was approximately 120 s.

Jan 1, 1993

By Robert J. Hundhausen

This paper describes the methods and costs of sinking a 2-compartment shaft at the Hope mine, Clark Fork, Idaho. The Hope mine is owned by the Hope Silver-Lead Mines, Inc. Albert E. Nash, of Clark Fork, is president and manager.

Jan 1, 1948

By B. Zane Egan

The Calsinter process for recovery from fly ash involves sintering the fly ash with calcium sulfate and calcium carbonate at 1200°C, followed by a dilute sulfuric acid leach step. Flue gas desulfurization sludge containing calcium sulfite, calcium sulfate, and unreacted calcium carbonate may be substituted for the calcium sulfate and calcium carbonate. Conversion of aluminum in fly ash by the sintering process to an acid-leachable species was measured as a function of sintering time and temperature in the range of 800°-1200°C The sinter-leach steps were investigated using thermogravimetric analysis, x-ray diffraction, scanning electron microscopy, and elemental analysis. SEM photographs indicated that the glassy spheroids in the original fly ash were converted to a crystalline structure by the sintering reaction.

Jan 1, 1980

By G. Richards Gwinn

Vermiculites are secondary minerals formed by the: alteration of biotite and philogopite mica and are associated with basic rocks such as dunites, serpentines, and pyroxenites. Vermiculite was first described by T. H. Webb in 1824. It remained a mineralogical curiosity until 1913, when the first commercial deposit was discovered in the Turrett mining district of Colorado. Expanded or exfoliated vermiculite was first marketed in 1915 from a deposit in this district 5 miles southeast of Hecla, Colo. This activity was brief, but successful and continuous commercial development began in 1921 in Montana. 'Deposits in other States have been found and developed, but Montana is by far the largest producer. Vermiculite has also been found in South Africa, Western

Jan 1, 1944

By C. D. Litton, I. E. Perera

This report presents the results of experiments to evaluate different types of mine fire sensors in an underground mine environment using a commercially available atmospheric monitoring system. To determine how well carbon monoxide (CO) and smoke sensors respond for purposes of fire detection, experiments were conducted using test fires of different mine combustibles and for both flaming and nonflaming combustion. The experiments were designed to assess the response of fire sensors to different contaminants and different contaminant levels produced from the test fires. The experiments were performed in the Safety Research Coal Mine at the U.S. National Institute for Occupational Safety and Health’s Bruceton Research Facility in the presence of an average ventilating air velocity of 1.6 m/s (315 fpm). Five fire sensor stations were located downstream of the test fire at fixed locations, with each sensor station consisting of four sensors: a CO fire sensor and three different smoke sensors, of which two were evaluated by the Mine Safety and Health Administration (MSHA) for intrinsic safety and the third was used extensively in underground mines overseas but not evaluated by MSHA for intrinsic safety. All four sensors were mounted near the center of the entry and in the upper onethird of the entry height. A UL-listed combination ionization and photoelectric smoke sensor was mounted near the roof at the first sensor station and its responses were compared against the responses of the four CO and smoke fire sensors. Sensor response data, contaminant travel times, and the impact of fire on the existing ventilation flow are discussed as they apply to earlywarning fire detection. Of significance in the analysis is the need for performance standards for mine fire sensors in order to provide for consistent and timely early warning of developing fires.

Jan 1, 2014

By W. H. S. McFarland

THE Yukon Consolidated Gold Corporation, Limited, a Canadian company, operates alluvial gold dredges in the Klondike goldfields of Yukon Territory. Its operations are of unique interest to Canadian mining as it is the only large-scale placer mining operation of this type in Canada. Its properties lie in the valley of the Klondike river and its tributaries, Bonanza, Hunker, Bear, Last Chance, and All Gold creeks, and in the valley of Indian river and its tributaries, Dominion, Gold Run, Sulphur, Eureka, Montana, and Quartz creeks. At the end of 1938, they consisted of 1,650 placer mining claims and 9 leases or concessions. They cover a belt with an area of approximately 1,000 square miles. This vast area covers in part claims which have been previously worked by other methods such as 'drift' and 'open-cut' mining, and areas which were too low grade for such methods. The ground held by the Company is not held in freehold but in the form of mining claims and mining leases granted by the Dominion Government under the provisions of the Yukon Placer Mining Act. Full-size creek claims are 500 feet in length by 1,000 feet on either side of the base-line. Hill and bench claims are 500 feet up and clown the valley and 1,000 feet at right angles to the valley. All claims are held on the basis of an annual renewal fee of $10 for each claim plus 'representation work' of an assessed value of $200 per claim per annum. For the purpose of such representation work, claims may be 'grouped'. This means that work done by one dredge is sufficient to 'represent' a comparatively large block of claims. It is only in this way that it becomes possible to consider operations on a large scale over a term of years, for such operations would obviously be impossible on law-grade ground if representation work had to be done separately on each individual claim in each year.

Jan 1, 1939

By B Smith, R Gelson

Springvale Colliery is an underground longwall mine situated approximately 10 km north-west of Lithgow in the western coalfields of New South Wales. Following a full-scale review of the mineÆs ventilation system in mid-2010, it was clear that the mine by early 2013 would become ventilation constrained as a result of the increasing size of the mine workings, the predicted worsening tailgate conditions and plans to introduce a fourth continuous miner unit. This realisation led Springvale to embark on a major upgrade of the mine ventilation system that would meet short-term and life-of-mine (LOM) requirements.Included in the upgrade project was the installation of a new high pressure centrifugal main exhaust fan that is capable of overcoming the high resistances imposed frequently on the circuit by restrictions in the tailgate airway. The new fan featuring a 2.5 MW motor is designed to be capable of operating at a quantity of 250 m3/s at a pressure of 7.9 kPa, a substantial improvement over the previous system, which had an operating duty of approximately 145 m3/s at 1.9 kPa. The new fan is of a centre hung design and features a backup diesel motor to maintain ventilation in the event of a power outage.Structural engineering analysis determined that under the operation of the new main fan the existing standard of ventilation control devices (VCDs) at Springvale would not be adequate to withstand the increase in differential pressures. As such, an upgrade of critical VCDs was undertaken utilising a novel high flexural strength (9 MPa) shotcrete and thin spray-on liner, which help serve to safeguard the structural integrity of the appliances and prevent increased leakage as roadway conditions at VCD sites deteriorate over time (a serious problem in many areas of the workings at Springvale).In addition to the main ventilation system upgrade, a separate upgrade focusing on improving development face ventilation was also undertaken. This upgrade included the purchase of two high capacity (22 m3/s) variable inlet vane (VIV) auxiliary fans to facilitate comfortable development face ventilation.The upgrade of the mine ventilation system at Springvale has been three years in the making, but has removed a major business risk in that it has afforded mine planning and operational flexibility (a fourth unit can now be introduced) for the LOM, and importantly provided unprecedented levels of comfort to operators at the working faces where previously ventilation and heat issues were frequently reported. The impact of this on the morale of the workforce, and hence their output, should not be underestimated.CITATION:Gelson, R and Smith, B, 2013. Life-of-mine ventilation system upgrade at Springvale Colliery - A case study, in Proceedings The Australian Mine Ventilation Conference , pp 79-86 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By Kwangmin Kim, Junnhyeok Park

In the hard-rock mining industry, the generation of fines during blasting is an important issue because it has a significant effect on production processes. Although various approaches have been used to estimate fines generation in recent decades, as a practical matter, measuring the amount of fines is nearly impossible given the technical limitations and the scale of mine blasts. In this study, a dynamic PPV damagemodel was developed and applied to predict fines generation as a result of blasting. This modified version of the crushed zone model (CZM) considers dynamic rock properties and peak particle velocity (PPV), which represents the induced stress in blasting. Dynamic rock-fracturing tests were conducted using a split Hopkinson pressure bar (SHPB) to determine the parameters that represent the relationships between rock strength and strain rate as well as the relationships between fines amount and strain rate in the model. A case study was conducted that entailed determining the radius of the crushed zone for given blast designs and rock properties and then measuring the fines amount within this crushed zone. This case study indicated that the dynamic PPV model can provide a rough estimate of fines generation for given dynamic rock properties and blast design parameters and that this method has the potential to be a useful indicator, or index, of fines generation.

May 16, 2020

By R. A. L. Drew, G. Mendoza-Suarez, J. Filipi, R. Vintila, J. A. Kozinski

Economics and environmental considerations along with the increasing demand of hydrogen encourage development of novel technologies such as plasma processing of hydrocarbons and thermal cracking of natural gas. Plasma discharges, either in thermal or non-thermal regimes are expected to allow low temperature and fuel flexible on-site hydrogen generation. The main drawback of thermal plasma reformers is the high-energy consumption resulting from high-temperature operation. On the other hand, non-thermal plasma, generated by dielectric barrier discharge (DBD), is able to simulate the chemical reactions employing much lower energies than those required by thermal treatment processes. The non-thermal plasma process allows for instance, a direct conversion of methane into hydrogen and carbon black with no CO2 release. The focus of this research was on the GHG-free method of H2 generation in compact non-thermal plasma reactors using low, medium and high permittivity dielectric ceramics. A stable, non-thermal plasma was generated by placing a dielectric ceramic between two electrodes with a 25 thou gap and applying an alternating current of 1-5kHz and voltages of 4-8kV. In order to ensure energetic efficient plasmas, experiments were conducted to analyze the behaviour of different permittivity ceramics. It was found that the dielectric properties of a ceramic, when used in a DBD reactor, have a strong influence on the discharge characteristics, which in turn influence the power consumption. Higher dielectric constant resulted in higher conversion rates of methane (higher yield of hydrogen and carbon). At the same time, the mechanical properties of the dielectric material, which are closely associated with its processability, influenced its resistance to electron bombardment, as well as thermal and mechanical damage. Therefore a reliable ceramic should have good dielectric properties, in addition to good thermo-mechanical stability.

Jan 1, 2004

By David W. Brunton

(San Francisco Meeting, October, 1911.) MINE-DRAINAGE and the ever-increasing demand for water on the plains have within the past few years necessitated the driving of a great number of adits and tunnels, including many of considerable size and great length. In most instances, ex isting conditions have called for extreme rapidity of execution; and this necessity, coupled with the high altitudes at which most of the work has been carried on, excessive freight-rates, and difficulty -of access, has involved many complex and interesting problems. One of the most rapidly executed undertakings of this class is the Laramie tunnel, recently completed for the Laramie-Poudre Reservoirs & Irrigation Co. This tunnel is driven through Green ridge, a spur of the Continental Divide, which separates the Laramie river from the Cache-la-Poudre in Laramie county, Colo. Green ridge is extremely persistent, and further northward in Wyoming is known as Sherman hill, the highest point on the Union Pacific railway. At the point where the tunnel is driven, two opposing bends bring these streams within 2.5 miles of each other, with a difference in elevation of 500 ft. The rock exposed on the banks of the two rivers does not differ materially in hardness; and, without a geological study of the conditions involved, it would appear that the difference in the depth of erosion of the two streams is due principally to the greater volume of water at this point in the Cache-la-Poudre, which has a drainage-area above the tunnel-portal of 110 sq. miles, as against 30 sq. miles of natural drainage for the Laramie. To increase the water-supply at the tunnel, however, this latter amount has been augmented by two side collection-canals, which bring the available drainage-area up to 84 square miles. The nearest railroad shipping-point to the eastern portal is

Apr 1, 1912

By J. Jung, W. Keller, A. Zucht

"The agitator design for nickel high pressure acid leach autoclaves (HPAL) is critical with regard to the process result, i.e., the recovery rate. Further considerations during the design phase are the avoidance of acid hot spots which reduce the lifetime, due to corrosion of the wetted parts, including components manufactured from titanium. Besides the process knowledge to design HPAL autoclaves, tools such as, Computational Fluid Dynamics (CFD) supplemented by lab testing allow the design of optimized agitation systems. This paper describes the effect that different feed point locations have on instantaneous blending of the reactants. Furthermore, experiments and CFD show where abrasion issues might occur and how to obtain information about the static and dynamic forces acting on internals. We show how simulations can be validated by lab testing to ensure that the CFD models are applied in an appropriate way.INTRODUCTIONAgitated systems in hydrometallurgical processes have to comply with multiple process tasks and in many cases have to withstand extreme operation conditions such as pressure up to 50 bar, elevated temperatures of up to 250°C and exposure to very acidic or alkaline environments and abrasive ores. The process tasks range from instantaneous mixing of reactants, homogeneous suspensions of up to 65% wt. solids with coarse and heavy particles, enhancing the solid-liquid mass transfer for leaching, dispersing large volumes of reactants (gas-liquid, liquid-liquid mass transfer) and moreover to transport generated heat e.g., from exothermic reactions through the vessel walls or internal heat exchangers if required. For economies of scale, agitator systems have reached sizes of 5000 m³ for large open leach tanks with impeller diameters of approx. 6 m, while autoclaves nowadays have exceeded 5.5 meters in diameter with a power demand for a single compartment drive between 300 - 400 kW. In parallel all process industries require a more efficient use of resources, to generate less by-products and higher yields, while ore-bodies tend to be less qualitative and new process routes (e.g. direct leach) are developed. Besides all these facts the mixing solution must be robust and economic. In this paper we want to address our approach in the development and designing of HPAL agitation equipment."

Jan 1, 2012

By Paul Sterling

1. INTRODUCTION. THE general impression regarding the preparation of merchantable anthracite is that it is confined to a colossal, grimy structure, called a "coal-breaker." This name is misnomer; for the desired result is not to break the coal, but to prevent its being broken. Preparation may be said to begin at the face of the chamber, with the mining and loading of the coal. Local conditions vary, not only in the same field or basin, but also in the same mine, so that there is no fixed empirical rule governing the method of blasting or cutting coal. Tests should be made, when possible, to determine the explosive, or the mechanical coal-cutter, which will produce the largest percentage of what are locally known as " lump " and " prepared sizes " of anthracite. The prepared sizes are those mostly consumed for domestic purposes. All other sizes might be called by-products of the anthracite industry; for they are not especially desirable, being the degradation resulting from the mining and handling of a brittle or laminated material. Being low in volatile combustible matter, anthracite burns most successfully when nearly of a uniform size, permitting the easy passage of air through the voids. This accounts for the large number of sizes into which the coal is separated. Table I. gives the various sizes, the diameter of ring over and through which each size is made, and the usual purpose for which it is employed.

Oct 1, 1911

As the surrounding environment continues to change and evolve, mine managers face a changing climate of expectations. TodayÆs mine managers must juggle competing pressures to deliver sound social, environmental and economic results. Leadership is a fundamental tool for the effective mine manager. Whilst mine managers require solid technical and operational skills, importantly the manager must be able to engage a workforce, build and retain employees and seize opportunity for growth and development when presented. An important tool for engaging employees in the business at Rio Tinto Aluminium is the business improvement programme. At Rio Tinto AluminiumÆs Weipa mine, the business improvement methodology Six Sigma is used to deliver measurable, sustainable outcomes for the business. The next step in Rio Tinto AluminiumÆs improvement journey is to implement Lean Manufacturing at all managed operations. The operating environment for mine managers continuously evolves and effective mine managers must be flexible and adaptive to meet challenges. Governance and regulation constantly change in an environment of commodity cycles and finite resources. This increases pressure on the economic return achieved by the operation. As such, effective mine managers must be aware of and manage the operating environment û the broader, issues-based environment not just the immediate day-to-day responsibility of mine managing. This includes delivering on safety, community and environmental priorities. At Rio Tinto Aluminium, part of managing the business is via investment in the area of social partnerships to engage employees and the broader community in Rio Tinto AluminiumÆs commitment to sustainability. The Future Reef partnership entered with the Great Barrier Reef Research Foundation in 2005 forms an important part of Rio Tinto AluminiumÆs climate change strategy. This four-year, A$1 million investment funds programmes looking at the effect of ocean acidification on the Great Barrier Reef. The partnership is a unique example of industry and science working together on an area of mutual and national concern. Modern mine managers require a broad set of skills to effectively deliver outcomes. TodayÆs mine managers must make innovative and courageous responses to determine todayÆs strategy for tomorrowÆs future.

Jan 1, 2006

Satisfactory means of managing growth in boom towns is a concern in mineral, energy and other large industrial developments. This session will include examinations of socioeconomic impacts, major issues such as social disruption, case studies, methods of managing growth, and concerns involving Indian lands. Innovative methods will be offered to assist the public, government, and industry in finding solutions to managing growth in rapidly growing communities.

Jan 1, 1979

By R. P. Townsend

It is a widely accepted "fact" that a Koepe friction hoist is generally the best solution for production hoisting when compared to a double drum hoists. This would appear to be true if one looks at the initial capital cost of just the hoist, and also if one compares the size of the motors selected for the duty. But is this the whole story? What are the longer term costs involved in the hoist's operation, and what are the relative efficiency's of the two designs? Perhaps the Koepe hoist design enjoys a better reputation than it deserves.

Jan 1, 2011

By C R. Fountain, W R. Cannings

The zinc-lead-silver mineral resource at Lady Loretta ranks amongst the worldÆs richest when measured in terms of in situ metal grades. However, the project remains undeveloped 28 years after its discovery in 1969. The primary obstacle to development has been the fine and complex grain structure of its ores, which make flotation concentration inefficient even with fine grinding. The size and remote location of the deposit have also hindered exploitation. BUKA planned to directly fume the volatile target metals from the ore when it acquired the project. Intensive, post-acquisition modeling showed the innovative processing route to be uneconomic, notwithstanding high metals recovery and low waste content in fume product. Progressive modifications and supplements to the underlying fuming process enhanced economics and resulted in a new mine-to-metal processing route for zinc-lead-silver ores. The proprietary, three-stage BUKA Zinc Process offers technical, economic and environmental advantages. It is expected to find widespread application in the treatment of ores and residues. However, neither continued R&D nor application to Lady LorettaÆs currently delineated resource can be justified under prevailing market conditions. The objectives and results of each step in the process development sequence are outlined with reference to their impact on the commercial viability of the Lady Loretta project.

Jan 1, 1998

By J. F. Harkom

Introduction The importance of the preservative treatment of mine timbers need scarcely be stressed here. Increasing the life of mine timbers will reduce one of the major costs of mining and also conserve the available timber supply which lies within easy access of the mines. When treated, several species of timber may be used which otherwise could not be considered, owing to their short life. Another feature which should appeal to the mining industry is that wood preservatives are a mine product, and the benefit to be derived from the increased consumption of wood preservatives due to the example set by mine owners is not inconsiderable. Mine timbers may be divided into three classes when considering preservative treatments. (1) Timber obviously not profitable to treat owing to long natural life or short period of time in service. (2) Timber that obviously should receive protection from decay. (3) Timber installed in locations where the length of service required will depend on future developments, so that preservative treatments might or might not prove to be a profitable investment.

Jan 1, 1930

By M. Hermanus, N. Coulson, N. Pillay

"SynopsisThis paper assesses the effectiveness of the Mine Occupational Health and Safety Leading Practice Adoption System (MOSH) and its potential to improve mine health and safety in South African mines. Developed by the Chamber of Mines, which represents the majority of the country's large scale mining employers, MOSH was devised to accelerate progress towards achieving health and safety milestones, which were set by tripartite agreement in 2003. The paper documents and builds on the findings of a study conducted by the Centre for Sustainability in Mining and Industry (CSMI) in 2011 that evaluated MOSH strategy, structures, and process of implementation.The study found that MOSH operated across the mining sector, was directed and dominated by experts and, despite best efforts to include other stakeholders, was led by employers. Statutory worker health and safety representatives and structures were not integrated into the complex change process developed by MOSH. The Mine Health and Safety Inspectorate (MHSI) and organized labour were ambivalent about direct involvement in MOSH and preferred regulatory measures to enforce the participation of mines. MOSH interventions were not targeted at mines with a poor health and safety record, and MOSH lacked a baseline from which to track impacts on sector-wide health and safety performance. The leading practices most widely adopted by mines were designed to improve, rather than fundamentally alter, existing practice. Although the depth of engagement with MOSH among stakeholders and on mine sites varied, mining companies, labour representatives, and the Mine Health and Safety Inspectorate (MHSI) saw the programme as significant.IntroductionIn 2011, the Chamber of Mines commissioned the Centre for Sustainability in Mining and Industry (CSMI) to evaluate the progress and effectiveness of the rollout of the Mine Occupational Health and Safety Leading Practice Adoption System (MOSH). CSMI, based in the School of Mining Engineering at the University of the Witwatersrand, is an independent research centre conducting health and safety research relevant to all major stakeholders in the mining sector. The purpose of the evaluation was to identify the factors that enabled or hampered the adoption of new technologies or practices. The timing of the evaluation, two years before the deadline for the 2013 safety and health milestones, allowed time for adjustments to be made. This paper summarizes the results of the evaluation and includes further analysis and discussion of the nature of the programme and the conditions that act to advance it or it hold back."

Jan 1, 2015