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By Lawson F

Synthetic calaverite (Au Tez) has been prepared and its physical properties checked.Simple flotation tests indicate that the recovery of calaverite should be possible using n-butyl or sec-butyl xanthate collectors under approximately pi I neutral conditions with a copper sulphate activator.Roasting calaverite in air at moderate temperatures resulted in its decomposition with the formation of elemental gold and tellurium dioxide.In alkaline oxygenated cyanide solutions, both gold and tellurium tend to dissolve. At pHs less than 14, about 50 per cent of the tellurium remains as elemental tellurium; however in very strongly alkaline solutions, essentially all of the tellurium is converted to the soluble tellurite ion (TeOl-).However, even at high pHs, the solubility of gold in the cyanide solution is still low due almost certainly to passivation effects.

Jan 1, 1991

The Junction Reefs gold bearing deposit is situated on the Lyndhurst Mining Field in mid-west New South Wales. It is located within a triangle of three country towns namely, Blayney, Cowra and Canowindra, all three townships are approximately 25 km from the current operational mining leases. The district is well developed, having been settled for more than a cen- tury. However, being close to the Cities of Orange and Bathurst it is real- lised, instantly, that mining leases have been pegged, in this area, almost boundary to boundary. The lease patterns are, with few exceptions, those which had been estab- lished more than seventy-five years ago. These types of lease patterns may not assist the proper exploitation of a large district where there have been many discoveries of gold, copper and other metals.

Jan 1, 1988

The 114th Annual General Meeting of The Southern African Institute of Mining and Metallurgy was held at The Country Club, Johannesburg, Napier Road, Auckland Park on Thursday, 11 August 2011. Welcome The President extended a special welcome to the guests and representatives of our sister institutes and other associations, and also to recipients of awards, senior members of industry, Honorary Life Fellows, past-presidents, our members and other guests, among them the following: F. Cawood, President, Institute of Mine Surveyors of South Africa C. Roode, President, Mine Metallurgical Managers' Association of South Africa M. Cresswell, Chairman, South African Coal Processing Society A. Hay, Immediate Past President, South African Institute of Electrical Engineers L. Gardner, President, South African National Institute of Rock Engineers J. Krynauw, President, The Geological Society of South Africa (GSSA)

Jan 1, 2011

By Kristie Tarr

Portland cement is primarily used to solidify backfill in underground mine workings and it represents a major cost in mining operations. CANMET-MMSL has invented an alternative binder technology that does not contain any amount of Portland cement and is made using waste materials, such as development rock and smelter slag. The technology has been successfully tested with many types of base metal and ferrous slag. Research conducted in collaboration with several mining operations in Canada has shown that the CANMET-MMSL binder has considerable potential as a replacement for Portland cement in mine backfill. An integral part of the overall mining operation, backfill is used for two main purposes: safety and environmental remediation. Depending on the mining method used, backfill provides a working surface, stabilizes stope and pillar walls, as well as the surrounding rock mass, and controls caving of stope backs. There are several benefits associated with the replacement of Portland cement in backfill, including reductions in (i) the footprint by placement of slag waste underground, (ii) the environmental effects and long term liability resulting from disposal and containment of slag waste on surface such as acid rock drainage, (iii) GHG as a result of reduced Portland cement usage (the production of 1 ton of Portland cement produces 1 ton of GHG), and (iv) the significant costs associated with reduced Portland cement usage.

Oct 1, 2010

By Hoffmann CF

Thermal conditions at depths of several k.i'-.r.,etres in hydrothermal systems are a major (actor controlling gold transport into the epithermal environment. Understanding of the coupling of thermal, metal and ligand (HZZ S) sources in the root zones of hydrothermal systems therefore becomes important for the application of tectonic and igneous petrochem- ical studies to regional scale precious metal exploration. The evaluation of favourable conditions in this source zone and application to explor- ation rests on a detailed knowledge of the gases, H2S, CO2 hydrocarbons and other trace components preserved in fluid inclusions. Recent developments in analytical techniques now permit examination of these components and the recognition of complex hydrocarbons in rluid inclusions from epithermal and other lydrothermal systems appears promising for ieoosit-source correlation.

Jan 1, 1987

Nickel WestÆs Kalgoorlie Nickel Smelter operates three Peirce-Smith converters, each processing 110 tonnes of matte per charge. The vessels are lined with chrome-magnesia refractory with a mouth traditionally constructed from steel liner plates, protected with cast refractory. Mouth refractory is damaged by molten material and the action of cleaning solid buildup off the mouth. Once damage has accumulated, the mouth must be frequently maintained with hot refractory gunning or a mouth leak may occur. Such a leak requires a 32 hour repair period. A converter mouth redesign program was undertaken with the aim of reducing the rate of mouth damage during operation, eliminating mouth leaks and shortening mouth replacement times during vessel rebuild periods. An overview of the redesign process and operational performance is contained herein.

Jan 1, 2005

Comparatively recent Tasmanian legisla tion established a series of rigid control standards for environmental protection just as ma spectacular expansion of the mining industry was nearing completion. Upgrading existing protection to obtain the necessary licence to operate under these new regulations required further major works and involved a considerable outlay of non- productive capital at a time when escalating costs and falling metal prices were straining economic efficiencies to the limit. Late in 1974 a major environmental protection scheme was commissioned by the Electrolytic Zinc Company of Australasia Limited at Rosebery on the West Coast of Tasmania. This 4 million dollar project was specifically developed by the Company ahead of and to meet the new standards for control of total effluents discharged from its zinc-lead -copper-pyrites mine and concentrator.

Jan 1, 1977

By C. Stephan, E. Weiss, J. Trackemas, M. Sapko

The National Institute for Occupational Safety and Health (NIOSH), Pittsburgh Research Laboratory (PRL), in collaboration with the Mine Safety and Health Administration (MSHA), the mining industry, and seal manufacturers recently conducted a series of full-scale experiments within the underground experimental mine at PRL’s Lake Lynn Laboratory. The purpose of the experiments was toe valuate the explosion-resistant characteristics of several new seal designs for rapid deployment during mine emergencies. These seals can be deployed in 6 to 10 hr and are capable of with standing explosion overpressures in excess of 140 kPa (20 psi). These novel seal designs use available mine materials, do not require conventional rib hitching, and, most importantly, can substantially reduce exposure time for coal miners during sealing and mine recovery operations.

By Thirumalai K, Peluso R. G

The United States has more than 45 billion tons of economic coal reserves in seams above 10 feet thick and current underground production from thick seams represent less than three per cent of the total production. A tripling of underground production from thick seams is necessary within the next 10 years to meet U.S. coal production demands. An analysis of underground accident and production data is presented in the paper. A study of accident and injury distribution in different coal seam heights in the eastern and western part of the United States in seams ranging in thicknesses from 5 to 15 feet indicates that the seam thicknesses do not produce adverse impact on underground injury incidence. Accidents associated with roof falls and haulage account for about 70 per cent of underground mining injuries.

Jan 1, 1976

The large, low grade, Kidston Gold Mine in North Queensland has achieved outstanding economies of scale and profitability. The total mineable ore reserve including mined to-date (as at December 1993) was 70.75 million tonnes at 1.54 grams gold per tonne. After nine years of mining, grade control mine production routinely reconciles against mill production and ore reserves to within five per cent of contained gold. The grade control system developed at Kidston is examined in detail, with emphasis on the geological thinking behind the strategies, as well as the development and application of a computerised, graphical production control and reporting system. Reconciliation procedures and results are explained, illustrating the success of geostatistical methods, as a risk management tool, in both ore reserves and production grade control.

Jan 1, 1994

By J. P. Conway

The yielding-rock-bolt concept, as developed in South Africa, consists of a smooth-bore die or collar fitted to a standard rock bolt. Laboratory testing at the Bureau of Mines Spokane Mining Research Center under slow and fast strain rates showed that extrusion loads can be controlled by varying the configuration of the die bore and that theoretical analysis (using basically Sachs' theory of wire drawing) predicts extrusion loads of the different die-bore configurations. A derived equation, based on this research, can be used for designed die-thread combinations for any desired extrusion load. Dynamic loading resulted in slightly higher loads (15 percent) than static loading. The strain hardening effect, which increases yield and ultimate strength, was partly offset by adiabatic heating of the threads, which decreases strength.

Jan 1, 1975

By Royal Jackman

Two comprehensive papers have appeared regarding the forms of copper that occur in smelter slags, one by Frank E. Lathe1 and the other by C. G. Maier and G. D. Van Arsdale.2 These authors comment on other published results and draw conclusions from their own investiga-tions. The development of X-ray examination of minerals and improve-ment in high-power microscopic methods make it possible today to get additional evidence by means that were not available to earlier investi-gators. The present work was confined to reverberatory slags obtained from five different plants. Some definite conclusions were reached regarding the forms of copper present in these slags. In most cases these agree with some of the findings of Maier and Van Arsdale but new methods of attack were used in the investigation.

Jan 1, 1933

By L. von Ketelhodt

Dual energy X-ray transmission (DE-XRT) sorting is a recent development in the range of sensor-based sorting technologies available today. DE-XRT is particularly suitable for dry coarse coal beneficiation in the size range -120 mm +12 mm. In this paper, we describe the technology and show the results of a number of test runs conducted on different types of coal from the USA and South Africa. The results have shown that DE-XRT is an effective technology not only for deshaling of coal and removing pyritic sulphur but also for separating coal and torbanite. The use of dry deshaling methods will be more important as water availability becomes a greater concern. DE-XRT is one such technology which will be incorporated in future dry coal processing plants.

Jan 1, 2010

By John S. Pack

The last 25 years have seen rapid expansion in the use of helical screw pile foundations and tiebacks for new and retrofit construction of buildings and earth retention structures. An estimated $100 million was spent in 2002 on helical foundations and tiebacks in the United States alone. While design information is available in the literature, information regarding quality control, inspection and performance monitoring is lacking. Recognition of at least one manufacturer's helical foundation material by the Uniform Building Code, Standard Building Code, and BOCA (all three codes now combined into the ICC International Building Code) has given added urgency to the dissemination of reliable and practical quality control, inspection and performance monitoring procedures. This paper describes a set of such procedures that have been followed for 17 years by engineers experienced in the industry who have directly installed or been involved in the installation of over 140,000 helical foundations and tiebacks in divers soil conditions for various types of structures, including earth retention structures. Topics covered include design responsibility, building code listings and requirements, manufacturer ISO certification, manufacturing process, material and installation specifications, installation contractor certification, field placement, installation procedures, field inspection, building code inspection and performance monitoring. The paper concludes with a step by step example of practical quality control, inspection and performance monitoring procedures on a typical helical foundation project.

Jan 1, 2003

By R. K. Rath

Adsorption, electrokinetic and flotation studies were carried out. The maximum density of adsorption of guar gum was obtained at pH 7.5 on sphalerite and at pH 11.5 on galena. Flotation recovery of sphalerite was reduced only marginally by the presence of guar gum in the pH range investigated, whereas recovery of galena was reduced to about 20% at pH 12. Differential flotation tests on binary mixtures indicated that 10 ppm of guar gum can depress galena and separate it from sphalerite at around pH 12.1. Co-precipitation tests confirmed the formation of a metal ion-guar gum complex in the bulk solution, suggesting that this is the precursor to adsorption. The adsorption isotherms for both minerals followed Langmuirian behaviour, but adsorption of guar gum on galena was significantly higher than on sphalerite and dissolution tests indicated that the concentration of Pb ions released from galena was an order of magnitude greater than that of Zn ions dissolved from sphalerite

Jun 21, 1905

By J. J. Wallace

This report describes the initial phase of Bureau of Mines research in the hydraulic mining of bituminous coal. The mining site and equipment are described, and the test procedures and results obtained with a bar-mounted monitor are given. Tests showed that hard Pittsburgh-bed coal can be mined hydraulically from a solid face at water pressures of 4,000 pounds per square inch.4 Coal was penetrated to a depth of 4 feet in 20 seconds with 225 gallons of water per minute coming from a 3/8-inch nozzle at 4,000 pounds per square inch pressure. Some difficulty was encountered in cutting the binders occurring in the coal; it was not possible Lu penetrate directly the overlying draw slate.

Jan 1, 1961

By R. K. Koch

The Bureau of Mines produced several series of titanium castings in order to investigate the feasibility of producing commercial-grade titanium castings in bentonite-bonded olivine or zircon sand molds. The use of these molds for titanium casting was investigated as a possible alternative to the industrially used rammed graphite process. Parameters investigated were mold mixtures, mulling, gating, venting, drying, and mold washing. The investigators found that castings with superior ductility and fatigue life, compared with rammed graphite castings, could be made by fume-free pro-cesses in molds bonded by western bentonite, using either olivine or zircon sand. Zircon molds were satisfactory for both light-and heavy-sectioned castings. However, olivine molds were suitable only for light-sectioned castings because the mold-metal reaction became excessive during the pouring of heavy-sectioned castings.

Jan 1, 1981

By Vernon O. Markworth

This report contains the results of tests performed on three large diesel engines to determine their ability to meet selected criteria of the Mining Enforcement and Safety Administration Regulations for equipment used in gassy, non-coal mines. Study efforts were first directed toward determining the types of equipment expected to be used in underground oil shale mines. Three typical engines in the 800-1200 horsepower range were then selected for testing. Intake flame arresters, exhaust scrubbers, and water jacketed exhaust system were designed and built for each engine. During testing, each engine was evaluated for its gaseous emissions output, adequacy of the exhaust gas cooling system, ability to withstand internal explosions, and adequacy of the flame arresters. Surface temperatures of the engine and exhaust cooling system were determined under full load operation.

Jan 1, 1978

By Descour Jozef, Suguru Shirasagi, Takuji Yamamoto, Koji Murakami

For TBM tunneling no visual inspection of excavated ground is possible. This may hinder the high-speed excavation, particularly in complex ground conditions. The TBM Excavation Control System was developed for better prediction of geological conditions ahead of the tunnel face during excavation. The seismic reflector tracing produces volumetric images of anomalies in the ground in “near-real time.” These images are verified using logging data from pilot boring and TBM driving data, to improve reliability and precision of ground mapping. Also good correlation was obtained between the rock strength index computed from TBM data, and one derived from volumetric seismic images.

Jan 1, 2007

By Scott Chesman

Increased TBM performance is leading the way for resurgence in tunneling activity in NYC. Tunnels will be excavated in the same geologic formations as previously excavated D&B tunnels whose construction records are providing valuable insight into the prediction of rock mass behavior. This report compares an eight mile stretch of NYC Water Tunnel #2 with the recently excavated eleven mile stretch of the TBM driven Water Tunnel #3. Comparisons of the type and amount of rock support installed as well as water inflows and grout quantities are made. Rock mass characteristics specific to TBM performance are also evaluated.

Jan 1, 2005