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By G. Henry, S. J. Domvile

Arsenic management practices at the Con Mine in Yellowknife, Northwest Territories have evolved over the last fifty years of operations under changing regulatory, economic and technological conditions and incentives. As a result of a processing upset in the mine' s arsenic trioxide reclamation plant circuit in August 1988, arsenic levels in the mine' s tailings pond rose from 30 to over 100 mg V. At these arsenic levels, water treatment operations were unable to meet water licence discharge criteria and the mine itself was under risk of closure due to limited water storage capacity. Under these internal pressures, the mine initiated its own research initiatives designed to restore water treatment operations. The new process developed from the mine's research, utilized the mine's existing water treatment plant hardware but introduced a pretreatment step involving a discrete sludge recycle and removal system. In February 1989, water treatment operations resumed under the new process.

Jan 1, 1992

By J. Yordan, J. Zinterer

Effective removal of ink particles by froth flotation is of up-most importance in paper recycling. In this study, the potential use of talc particles as carriers of difficult-to-float fine ink particles is investigated. In order to accomplish ink particles removal, the interactions between talc and oily- ink particles in aqueous solutions containing flotation chemicals was studied by zeta potential distribution measurements and with the impinging jet apparatus. The chemical conditions under which talc-ink adhesion occurs are identified and reported.

Jan 1, 2003

By W. A. Hustrulid

Introduction A problem that has faced mining engineers and mining geologists for many years is how to best explore a particular prospect so that the basic decision as to whether the material present is ore or only high-grade rock can be made with some confidence. It is obvious that one could not begin a large scale mining program on the basis of tests made on a few hand samples. On the other hand, one could not be 100 percent certain as to the average grade or tonnage before beginning development, as this would require the orebody to be mined out in the sampling process. The basic objectives of the exploration program can be stated as (1) to reduce mining risk; (2) to lessen the cost of development; and (3) to increase the profits of mining. The exploration program should be terminated when these objectives are no longer being met. The construction of tunnels is a specific mining operation. In the exploration program one should gather the data needed to determine (1) the type of excavation technique(s) to be used; and (2) the rate of advance that might be expected. As in the evaluation of an orebody, with the data collected it should be possible to estimate mining costs and project life. Unfortunately, at the present time, it is not possible to do this at least when dealing with medium to hard rock types. The reason for this, it is felt, is basically the inability to identify what specific rock mass properties are of use in tunnel design and to specify how these may be obtained in an exploration program. In short, the exploration program should be designed to give information regarding both the volume (length) and 'grade' (in

Jan 1, 1997

By Y. C. Lo

Grinding process optimization is an exciting new tool for maximizing the performance of existing mineral processing plants. This paper discusses the methodology of optimization which involves plant sampling, pilot tests, modeling, computer simulation and plant verification. The methodology developed emphasizes the interactions among operating variables and design options. Two example applications demonstrate that AG and SAG optimization provides the basis to increase grinding throughput up to 10 percent. This sys- tem optimization technology has been proven to be very cost effective for grinding plant performance improvement.

Jan 1, 1998

By Jeffery L. Kohler

The characteristics of mine airstreams, such as their magnitude in the time and frequency domain and their spatial distribution, as defined by isovels, must be considered when making a measurement. The possibility for erroneous measurements is greatly increased when fixed- point sensors for mine monitoring systems are used. However, an a priori understanding of the airstream characteristics can be used to reduce the possibility of erroneous readings. This paper describes the problem, presents data to illustrate the nature of the problem, and provides recommendations for alleviating the problem.

Jan 1, 1987

By C. Bazin, D. Hodouin

Dynamic experiments were performed in a continuous open-circuit 40x40-cm ball mill using a pseudo-random binary sequence of the feed rate and measuring the variations of the discharge particle-size distribution. The impulse response is calculated by a cross-correlation technique. Then a model involving a discrete transferfunction and a time-series stochastic equation is calibrated using maximum likelihood methods. Based on this empirical model, a minimum variance controller with constrained input is designed and its performances are compared, by simulation, to the performances of a conventional PID regulator.

Jan 1, 1987

By Thomas W. Healy, David V. Boger, Yee-Kwong Leong, Lee R. White, Peter J. Scales

The concentration of mineral slurries by conventional thickening devices is discussed. The role of additives on the compression of mineral slurries is also examined. Results for a range of flocculation conditions are presented. The compression of flocculated mineral slurries is found to be highly dependent on the fundamental particle-particle interaction forces and hence, the rheology of the particulate fluid. It is demonstrated that a detailed knowledge of the properties of both the mode of operation of the thickening device and of the solid/liquid interface is required for improvement in the rate and in particular, the extent of dewatering.

Jan 1, 1995

By Lj. Obradovic

The aim of this paper is to study the feasibility of copper and gold recovery from the old flotation tailing dam at Bor, Serbia. Laboratory leaching experiments were carried out using a composite sample taken by drilling from 16 - 40 m depth. Different oxidation agents as FeCl3, Fe2(SO4)3 and H2O2 were used. An H2SO4 solution with a pH less than 3 was used for leaching. The influence of a number of parameters on the recovery of both elements as temperature, pH, duration of leaching and concentration of oxidation agents was also studied.

Jan 1, 2006

By Robert C. Dunne

Nearly one third of Australia's total gold product is produced in the Kambaloa - Kalgoorlie - Leonora Goldfields. There are presently some 25 gold mines in the area with the possibility of another six plants being constructed in the next year. Details of the gold extraction techniques used on these mines will be discussed and certain innovative technologies and problem areas will be highlighted.

Jan 1, 1998

By Ali Sogue, Steven Schurman, R. Jensen

This paper presents the results of the remediation of the Gregory Gulch #1 Superfund site, an EPA Clear Creek Superfund project located in central Colorado. The Gregory Gulch #1 site was an historic gold mine and mill located within the city limits of Central City, Colorado. Remediation efforts included the use of the Envirobond™ additive to chemically bind the metals in 3,000 tons of acid generating mine waste that contained high levels of arsenic, lead, zinc and mercury. The toxicity of the mine waste amended with Envirobond™ was not only reduced to RCRA TCLP standards but also to the more stringent UTS standards. The final cost of the treatment was much less than standard industry solidification processes and significantly less than offsite disposal options.

Jan 1, 1999

By G. Gaidajis

Sea water samples collected from coastal waters in the vicinity of the Stratoni mining operations, in North-Aegean Sea were analysed for dissolved metals and elements. The maximum concentrations observed were one to three orders of magnitude lower than the environmental limit which coincides with the quality of sea waters suitable for swimming purposes. The quality of the coastal sea waters are affected by the natural mineralization of the area and the urban activities drained through local small rivers, the past mining activities present in the sea bottom sediments in the form of disposed tailings, and finally by the presence of the adjacent Mill-Flotation Plant. The relative importance of the treated final effluents discharged from the mining operations is considered to be insignificant.

Jan 1, 2006

By Paul E. Senseny

Data from triaxial compression tests per- formed at confining pressures between 0 and 100 MPa are used to evaluate parameters in a contitutive model that is based on microcracking. The tensorial formulation is reduced to equations that are specific to the simple Loading imposed in triaxial compression tests. Procedures for evaluating the model parameters are described, dependence of parameter values on confining pressure is discussed, and prediction of failure is assessed.

Jan 1, 1986

By Joseph C. Rota, Charles E. Ekburg

Introduction The Gold Quarry gold deposit is the largest bulk tonnage epithermal gold deposit in northeastern Nevada to be developed by Newmont Gold Co., formerly known as Carlin Gold Mining Co. Exploration and development of the deposit extended over a period of nearly 50 years before bulk tonnage mining became economically feasible. Proven reserves at Gold Quarry are currently estimated at more than 255 t (8.2 million oz.) of gold, accounting for more than 40% of the total Carlin Trend mineable reserves for 1986. Milling began in late 1985; dump leaching of lower grade ores began in May of 1986. The mill has exceeded the initial design throughput rate of 6.3 kt/d (7000 stpd) and is now processing more than 8 kt/d (9000 stpd). The dump leach facility will process more than 7.3 Mt (8.1 million st) of lower grade ores in 1986. The Gold Quarry ore body is to be developed by an open pit that will eventually be 1830 m (6000 ft) long, 1220 m (4000 ft) wide and 300 m (1000 ft) deep. The mine currently produces 77 kt/d (85,000 stpd) on a 24-hour-a-day, seven-day workweek. Planned pit production will increase to nearly 168 kt/d (185,000 stpd) in 1988. Production equipment currently includes one Demag H-/285, three Komatsu PC-1500 hydraulic shovels, two Cat 992C loaders and 21 90 to 135 t (100 to 150 st) haul trucks. Mining is conducted on 8 m (20 ft) benches within the Paleozoic

Jan 4, 1988

By S. K. Singh, J. Shepherd

Feather-edging, a major source of injury and fatal accidents in Australia, South Africa and the United States, refers to a phenomenon in which the roof at the goaf edge falls, often suddenly, as a thin wafer of rock that overrides conventional timber breaker lines. The fall may adversely affect a working bord at a distance of 15 m (50ft) or more from the goaf edge. Feather-edging typically occurs in relatively massive, strong roof strata such as sandstone or conglomerate. This paper presents the results of a test in which a concentrated row of fully grouted bolts were used to prevent feather-edging in an Australian pillar- ("total-") extraction coal mine. The test demonstrated that the bolts could resist feather-edging.

Jan 1, 2000

By John Turner, John A. Gibson, David Cass

Contents A. Introduction B. Description of Robbins Company involvement in several of the English Channel Tunnel projects C. Identification of project requirements and comparison of TBM features D. Description of the manufacturers separate roles in the -235 (T-1) TBM E. T-1 performance to January 15, 1989 F. Summary

Jan 1, 1989

By Mark Gershon

This paper describes an application of a new approach to mine planning and production scheduling in a gold mine. The technique, limited to use in open pit mines (but not limited to gold), has been described previously (Gershon, 1987). The-computer program used is the HOPS software, which has been described previously as well (Gershon, 1988). The mine is scheduled for the production of 8,000 blocks out of a mine having 25,000 blocks (50 x 50 x 10). The technique is based on the concept of inverted cones (Gershon, 1987). While it does not provide a true optimization of results, it does approximate the optimal situation. As opposed to most scheduling software that only serves as a computerized notepad for the scheduler, the use of this approach allows for a scheduling intelligence to be built into the software.

Jan 1, 1989

By R. A. Lowe, P. B. Malla

Smectite is a common impurity in the kaolins of Georgia.This impurity is harmful to the low-shear rheology of kaolin slurries in concentrations as low as a few weight percent. The deleterious effect of smectite on the low-shear rheology is due to the swelling of the mineral. Montmorillonite containing clays were treated to precipitate a compact brucite layer {Mg(OH)2} in the interlayer region of the expandable layer silicate mineral. This treatment forms ahydroxy-Mg-montmorillonite with characteristics similar to chlorite. This treatment effectively reduces the swelling capacity of the mineral and improves the rheological properties of kaolin slurries contaminated with smectite impurities.

Jan 1, 1999

By Dewey W. Marino

Conventional remote sensing applications for the exploration of natural resources has largely been the domain of low resolu­tion Earth orbiting systems such as Landsat™ which can sample a broad range of the spectrum. As the classic application of remote sensing, it has proven its worth through the discovery of numerous mineral deposits worldwide. Often this technique relies more on the spectral content of the imagery for narrowing potential sites on the ground, but often cannot reveal the detailed context of the observed response. As the dawn of the new era in remote sensing grows closer, high-resolution imagery is proving its worth for the definition of mineral potential and its cost sav­ing advantages for mine management.

Jan 1, 1998

By Gordon P. Riddler

IMMM Reporting Code 2001 – Some Developments -General definition of a Competent Person -Rules of Conduct with Guidelines -Table of Generic Terms with Guidelines -More specific to non-metallic minerals -Word ‘ore’ is not used for reserve/resource categories -More definitive on Mineral Exploration Results

Jan 1, 2003

By C. H. Bucknam, A. M. Raichur, M. Misra

Simultaneous dissolution of mercury along with gold occurs during cyanidation of gold ores. A method has been found for the efficient removal of mercury from the gold cyanide solution by treating with dithiocarbamates which form stable compounds with mercury. The mercury concentration in the leach solution can be brought down to low levels by adopting this treatment. Furthermore, it is also possible to stabilize the mercury in the ore heap itself by addition of this reagent so that mercury does not dissolve in the cyanide solution during heap leaching. Only trace amounts of mercury were detected in the pregnant solution obtained from a heap treated with dithiocarbamates. In this paper, process parameters are discussed in detail.

Jan 1, 1997