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By Alfredo Romero Quispe, Carlos Hoffman Sampaio

This work presents a study of characterization of activated carbons for the adsorption of Au(CN)2- complex. A comparative study of six samples of activated carbons, three Brazilian and three produced out of Brazil was made in order to determine their qualification for a performance in adsorption circuits in the extractive metallurgy of gold. The adsorptive capacity and the kinetics of adsorption were compared to the physical and chemical properties of each one. The influence of poluant ions on the kinetics and loading capacity of aurocianyde anion was also determined.

Jan 1, 1995

By H. L. Ehrlich

Processes involving biological solubilization of metal values from ores, or removal of mineral constituents that interfere with metal value recovery from ores by abiological means, published mostly in the last 10 years, are reviewed. Many of them, though promising, have yet to be tested on a pilot scale or applied industrially.

Jan 1, 1987

By H. V. Scotland

Lafarge Corporation's Texas Quarry, in Baltimore MD, achieved a substantial expansion of pit reserves by removing an inactive underground mine. The daylighting program, designed, and completed in 1997, open pit mined more than400 meters of room and pillar workings which were originally developed to recover high brightness Calcium Carbonate. The project proved to be a challenge throughout its course as the pit plan was modified and successful daylighting techniques were developed to remove the mine without adversely affecting the safety of the operation, quality of the stone recovered, or negatively impacting the surrounding community. The design parameters and techniques developed and implemented at Texas may prove of interest to other operators as they are faced with daylighting opportunities. This article will detail the challenges we faced and the solutions which made the project a success.

Jan 1, 1999

By Lynn B. Hales, Randy A. Ynchausti

Expert supervisory control strategies have been used for many years to improve operating revenues in comminution circuits. Typical improvements in capacity range from four to eight percent. Several case studies of results will be presented as well as a general discussion of the technologies used to achieve the improvements. Crushing. SAG milling and ball milling circuits will be discussed.

Jan 1, 1997

By Q. X. Yun, S. H. Liu

This paper provides a new approach to determine the opening layout in underground mining methods by means of genetic programming. Based on a set of random combination of openings, the layout of openings will gradually improve with the help of genetic operations, including reproduction, crossover, mutation and fitness calculation. The optimal solution will finally emerge according to Darwinian principle: "the survival of the fittest ".

Jan 1, 2002

By Dale J. Sadowski, Richard J. Switalski, Kyle R. Ott

This paper discusses design and construction aspects of shaft construction through rock saturated with petroleum hydrocarbons (crude oil). During the subsurface exploration phase for design of the Hilltop Interceptor project in Cleveland, Ohio natural crude oil was encountered at depths between 6.1 and 61 m below ground surface. The oil-saturated Euclid sandstone contained up to 12,000 mg/kg total petroleum hydrocarbons (TPH), various volatile organics, and had flash points as low as 18.9°C. Interceptor hydraulic design required that construction of access and/or drop shafts penetrate the layer of petroleum hydrocarbon saturated rock. This led to the design of a special lining and some special handling procedures for the excavated material.

Jan 1, 1995

By Gerald L. Tiley

When payloads and hoisting distances are beyond the capacity of a single headrope, a multi-rope hoist will cost less than, and require less maintenance than, several hoists with one headrope per conveyance. This paper describes the basic type of multi-rope drum and friction hoists in use today, the types of ropes available, and the essentials of a satisfactory installation.

Jan 1, 1981

By M. S. Vernon, J. J. Kellar, W. M. Cross, R. M. Winter, F. J. Johnson, A. G. Pommer

Three substrates (MgO crystal, CaF2 crystal and Mg plate) were used to construct thin layers of Mg(OH)2. Various routes were used to modify these substrates, including surface hydration and sol-gel coating. In each case, it was found (by using Fourier transform infrared spectroscopy) that thin layers of Mg(OH)2 could be produced. In the case of hydrated layers, the surface morphology of the Mg(OH)2 resembles the bulk platelet shape of precipitated Mg(OH)2.

Jan 1, 2000

By Donald P. Richards, Patrick Ramond, Martin Herrenknecht

Phase 1 of the second line of the Cairo Metro includes approximately 5.83km, of double track tunnels excavated in water bearing sand of the Nile flood plain. Closed face bentonite slurry shield tunnel boring machines 9.43m in diameter were used. State-of-the-art technology was used in TBM operations and guidance, with surface settlements averaging less than 14mm, and alignment deviations averaging less than 25mm. Production rates up to 580m/month were achieved, with average production of 4.8m/shift, 13.4m/day and78m/week. The completed tunnels, lined with precast concrete segments, are completely watertight under 20m of water pressure.

Jan 1, 1997

By Jacques L. Mauboussin

The EUROPEAN ORGANIZATION for NUCLEAR RESEARCH (CERN) has undertaken the construction of a LARGE ELECTRON POSITRON COLLIDER (LEP), near GENEVA (Switzerland). The facility includes the main 27 km long tunnelled ring, 18 shafts, 20 experimental caverns and many auxiliary galleries. Roughly 800 000 cu.m were excavated in the molasse at 50-140 m depths, using roadheaders for caverns and auxiliary tunnels and 3 WIRTH, 4.5 m diameter, fullface TBMs for the main circular tunnel. Each TBM performs 25-30 m/day. Provisory lining behind them uses either precast concrete elements or shotcrete. Works a e being carried out by a joint-venture of European contractors led by FOUGEROLLE (France).

Jan 1, 1987

By Corale L. Brierley

Bacteria have long been used for the extraction of copper during dump leaching of sulfide minerals and in the recovery of uranium from mined-out areas. However, bacteria can also be used in extraction of trace metals from copper ores and waste materials. Molybdenum, tungsten, nickel, cobalt, gold, silver, and other strategic metals can potentially be released from ores and wastes by biological processes. The chemistry and biology of these reactions, the potential for using the processes, and the state-of-the-art of the technology will be discussed.

Jan 1, 1983

By Robert Moore Lewis

A unit for separating minerals Into two prescribed size fractions, designated as a Lewis Hydrosizer, was developed at the North Carolina State University Minerals Research Laboratory Ore samples with different mineral compositions, including coal, were separated effectively with the laboratory continuous unit Commercial size units are in operation in North Carolina and Mexico, and under construction In Norway Additional units are being built or are in the planning stage at several companies.

Jan 1, 1983

By Curt Morgan

This paper will discuss the value of cream a common information model for the mining industry. Information models are a proven technique for quantifying diverse information in a non-proprietary and easily understood manner. Combining information models with emergent data exchange technologies such as XML and SOAP, the mining industry could substantially reduce the costs of sharing information, reduce dependence on proprietary information systems, leverage inexpensive PC desktop technology, and provide a solid foundation for simplifying mine information systems. The paper will provide an overview of information modeling, discuss practical and proven applications of the modeling technique in the mining industry, propose how such a model could be developed in a collaborative manner and discuss the benefits of such an effort.

Jan 1, 2002

By M. Ghiani, R. Peretti, A. Zucca

The paper deals with the experimental application of a pilot flotation column to baryte and fluorspar ores. The column has been installed in parallel with the cleaning stages of two different industrial flotation plants where the above ores are processed using conventional cells with mechanical impellers. The effect of several parameters, including froth height, wash water additions, pulp feedrate and air supply rate, has been investigated. It has been shown that by finely tuning the above parameters good flotation performances can be achieved. The experimental results demonstrate the greater versatility of the column flotation and its superior separation efficiency, especially for the fine particle size fractions, over conventional cells.

Jan 1, 1995

By Daniel Hodouin, Claude Bazin, Sami Makni

Computer systems, installed in mineral processing, are designed to accumulate massive amounts of real-time data. Frequently these data are only partially processed because of the lack of adequate methods and the limited accuracy of mineral processing sensors. Methods are proposed to estimate missing data and reconciliate sensor data on a real-time basis. They are based on dynamic extension of steady-state techniques such as the node imbalance minimization or the least-squares mass balance adjustment techniques. The methods are illustrated for simulated and actual flotation data. Their data upgrading ability could be used to improve process monitoring, control and optimization.

Jan 1, 1993

By M. H. Weinecke, B. P. Faulkner

This paper discusses the process for making lightweight aggregate, the waste materials that make good lightweight aggregate, the chemistry of making lightweight aggregate and the commercial prospects for making lightweight aggregate from wastes. Svedala Industries has been making lightweight aggregate (LWA) from waste materials for the last 10 years. Many claylike materials, such as coal fired boiler ash and washings from a granite quarry, can be used alone or with additional waste materials to produce commercially salable LWA.

Jan 1, 2003

By Colin M. Kelly

The Loveridge Mine, located near Fairmont, West Virginia, has been mining coal from the Pittsburgh Seam since 1958. As the mine develops its reserves it finds itself with increasingly distant hauls from the operating faces to the preparation plant. Initially, the mine was designed with track haulage. The coal was hauled to an underground rotary dump which fed a slope belt, to the preparation plant. As the haulage distances increased, production delays due to the track system's limitations became severe. To resolve this situation, a complete review of the haulage system was undertaken. Simulations of the present system along with future scenarios were conducted to help management effectively plan the haulage requirements of the mine for the remainder of its life.

Jan 1, 1986

By Levent Ozdemir, Roy H. Spitzer, Don W. Deere, John B. Blyler

This paper documents the construction of the Stanley Canyon Tunnel, the geologic conditions encountered, boreability of the rock, and the impacts of the conditions encountered on the construction. The 5.05 kilometer long (3.1 miles), 3.47 meter (11.4 feet) diameter, tunnel was driven through granites with a refurbished tunnel boring machine (TBM). Difficult ground conditions encountered included shear zones, high groundwater flows, and hard, tough, and strong rock. Detailed geotechnical studies during construction revealed that microscopic changes in the rock grain boundaries due to contact metamorphism, resulted in the hard boreability. Originally scheduled for five months, the tunnel construction required nearly three years, including periods of project shutdown.

Jan 1, 1995

By Frank F. Roxborough

The paper presents a brief account of the principal findings and an assessment of the practical value of a substantial international research effort into the mechanical excavation of rock that has been in progress over the past 30 years. This assessment together with an appreciation of the emerging trends in mechanical excavation suggests what are likely to be profitable lines of future inquiry.

Jan 1, 1985

By James W. Martin, Brad H. Droegmiller

As construction projects continue to get larger, greater demands are placed on systems to provide higher production rates at reasonable costs. This paper shows the application of dozer-trap loading versus other methods of moving bulk materials. Most conventional methods employ multiple types of heavy equipment to accomplish a single task. Trap loaders fed by dozers and discharging onto overland conveyors offer an alternative/economical means of high volume bulk material movement. This paper will discuss the process of trap loading to overland conveyors.

Jan 1, 1998