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By Q. Xu, P. Somasundaran

Adsorption of nonionic/anionic surfactant mixtures on kaolinite has been studied, with •Sodium dodecylsulfate as the anionic surfactant, and •Octaethyleneglycol mono-n-dodecylether as the nonionic surfactant. Synergistic interaction between these surfactants was found to cause adsorption of the nonionic surfactant with its hydrophilic chains protruding into the bulk, leading to substantial changes in wettability and dispersion characteristics of kaolinite. Similarly, hydrophobicity changes are observed also for silica particles upon adsorption of nonionic ethoxylated alcohols owing to possible changes in the orientation of the adsorbed surfactant molecules at the interface.

Jan 1, 1993

By S. J. Jung, F. Lock

This research came about because of the recognized need for a safe, easy way to line small-diameter bored raises (less than 150 cm). Currently, an operator must go down the raise and apply the concrete lining manually, using the shotcrete method of application. With an automated system, there would be no man positioned in the bore itself. All control functions could be commanded from a central location. Shotcreting in the confined space of a small-diameter bored raise presents problems that can be overcome by the application of shotcrete using a remote system.

Jan 1, 1995

By Qiang Ji, Richard L. Sanford

A laboratory-scale microcomputer-based autonomous excavation system has been developed that moves a pile of fragmented rock to a designated location using a shovel attachment on a robot arm. Navigation and excavation sub- systems interactively direct a robot excavator to move the shovel to the rock pile, intelligently load its bucket using a video camera, and dump the rocks to a designated area. Although research was conducted on a laboratory scale model, the system can serve as the basis for further work on a full-scale, robust excavation system.

Jan 1, 1993

By Anthony Busigin, Charlett Busigin, Colin R. Phillips

For the purposes of measurement and dosimetry of airborne radon daughters in uranium mines and elsewhere, it is important to understand their physicochemical state. This work deals with the chemical fate of 218Po in air. Extensive experiments were performed to determine the rate of neutralization, diffusion coefficient and fraction born charged of 218Po in air. The experiments were performed in a specially constructed apparatus of well-defined geometry. Careful control of experimental conditions made it possible to obtain more precise and detailed quantitative data than previously possible.

Jan 1, 1981

By David G. Chedgy, Edward A. Zawadzki, Robert D. Stoessner

Extensive research and testing in commercial facilities has clearly demonstrated that heavy medium cyclones are the most effective process for cleaning a 0.6 x 0.15mm (28 x 100 Mesh) coal at low separating gravities, less than 1.35. This paper describes testing performed to deter- mine system characteristics at these lower gravities and the type of circuitry required to maximize performance. The results of these studies include both pilot and commercial scale tests of cleaning 0.6 x 015mm (28 x100M) coal.

Jan 1, 1988

By Grazyna Dziurdzak, Robert C. Dunne, James H. Kyle

The pressure pre-oxidation of refractory gold concentrate from the Golden Mile has been investigated and the conditions of temperature, oxygen pressure and percent sulphide breakdown for maximum gold extraction optimised. Both tellurides and sulphides were oxidised under optimal conditions and deposited in the residue as oxides along with haematite. Under non- optimal conditions, a reactive basic ferric sulphate was formed instead on the unreactive haematite. Maximum gold recovery after cyanidation (tail < 1 ppm) is well in excess of that produced by the present roasting process (tail 3-4 ppm).

Jan 1, 1989

By P. W. Hunter

The construction of a major sewerage scheme requiring 15.3 km of 5.5m excavated diameter tunnel in basalt, mixed and soft ground has been undertaken by the Melbourne and Metropolitan Board of Works. A double shielded Tunnel Boring Machine was selected to excavate 13.7 km of basalt and mixed ground. Advanced methods for recording operational data on the TBM were introduced. Progress to date has shown that the TBM can excavate rock very effectively with a best weekly production of 178.8m; soft ground has been encountered and successfully handled.

Jan 1, 1987

By C. W. Benjamin

The paper covers the development of an efficient, "state-of-the-art" design approach encapsulating extensive research and development by Gulf on soft loading, low impact, zero spillage transfer chutes. The development, which interacts and interfaces the comprehensive methodologies for transfer chute design, allows Gulf to deliver detailed designs within 8-24 hours rather than the norm which is weeks or months. Outputs include 3D models of completed transfers and support structures along with rendered 3D representations of the design which can be fully manipulated around all axis in 3D.

Jan 1, 2000

By Carolyn S. Watkins, Thomas E. Ward, Debby F. Bruhn, Vern Winston, Mary Lou Rowland, Deborah K. Bulmer

The genetic characteristics of members of the genus Acidiphilium are poorly understood. As part of our study of the genetics of these bacteria, a search was made for an endogenous bacteriophage. Such a bacteriophage has been discovered. Several properties of the phage have been investigated. The phage has a lambdoid morphology and is somewhat larger than lambda. A variety of factors which affect phage stability have been investigated. The bacteriophage infects several of the strains that have been tested. Study of this bacteriophage should greatly increase our understanding of genetic mechanisms in Acidiphilium.

Jan 1, 1989

By H. Sevim

This paper summarizes the research effort in simulating the operation of "Underground Coarse-Coal Hydrotransport Systems" (UCCHS). The equipment of the system to be simulated is already optimally selected by using an analytical optimization model. The purpose of the simulation model is to test the performance of the system and to obtain the distributions of operating parameters such as water and power consumption and amount of slurry delivered to the preparation plant. Knowledge of the distributions of these parameters is essential for the efficient operation of the system.

Jan 1, 1987

By S. L. Bolivar

The Prairie Creek intrusion, near Murfreesboro, AR, is the site of the most famous diamond mine in North America. Three major rock types are associated with the intrusion-a hypabyssal peridotite, a volcanic breccia in which the majority of diamonds occur, and tuft. Previous studies, including geological, geophysical, petrological, and whole-rock and mineral chemistry are reviewed. The recent suggestion, by other workers, that this intrusion may be more correctly called a lamproite is examined. This has serious implications for diamond exploration in Arkansas and elsewhere in the US.

Jan 1, 1987

By K. N. Han

The adsorption of gold onto activated carbon in iodide solutions was studied. The adsorption rates were determined as a function of temperature, salt concentration and pH, as well as activated carbon concentration. A kinetic model was developed for the adsorption. The adsorption rate was believed to be controlled by a combined mechanism of film diffusion and pore diffusion with the film diffusion having the most significant effect. Experimental findings were in good agreement with the model developed. The apparent activation energy was found to be 14.9 kJ/mol.

Jan 1, 1995

By Roger Beckie, Leslie Smith, Craig Nichol

To study the hydrogeological processes that control the movement of water through unsaturated waste rock, an intermediate-scale (8m x 8m x 5m) waste rock pile has been constructed and instrumented. The constructed pile is monitored for moisture content, matric suction, temperature, matrix water chemistry, gas chemistry, gas pressure, rainfall, evaporation, discharge volume and discharge chemistry. The pile is built upon a grid of 16 contiguous lysimeters. The experiment is designed to investigate the mechanisms that create rapid water flow through a pile and its exchange with slower-moving matrix water.

Jan 1, 2000

By Cliff G. Paton, Sheldon B. Bland, Roger E. Melley

This paper looks at four critical lubricants used in the conveyor systems of the northern Albertan oil sand facility. The requirements for the lubricants used in the electric motors and gear boxes of the drive systems, the pulley bearing and the idler bearings are discussed in terms of the applications and the environment. A number of developments that have occurred in recent years are presented. Data from the field and from custom designed testing in the laboratory are used to support the role of simulation testing in problem solving in this area of technology.

Jan 1, 1996

By Hugh W. Rimmer

The design of comminution circuits and the evaluation of alternatives should be based on state-of-the-art equipment and appropriate design criteria - considerations that are often neglected by today&apos;s designers. This paper critically reviews common circuit designs, evaluates various alternatives for difficult-to-treat ores, and discusses the factors that should be considered when developing new plant designs or auditing existing plant performance. Data obtained from laboratory, pilot and plant-scale test work on a wide range of ores and circuits are used to justify the author&apos;s conclusions.

Jan 1, 1995

By M. J. Gula, S. S. Xue, E. P. Horwitz, J. T. Harvey

A study was conducted to control iron in copper electrolyte streams using Eichrom Industries&apos; new monophosphonic/sulphonic acid resin. The resin strongly and selectively extracts ferric ion over copper and cobalt from highly acidic copper electrolytes. The resin has a loading capacity of 27-g/L iron and can be readily regenerated. In addition, the new resin can easily be synthesized using commercially available starting materials. This paper presents the experimental results for iron control in copper electrolyte streams using the new resin and discusses its potential applications to other hydrometallurgical streams.

Jan 1, 2002

By J. P. McDonnell, L. A. Beckett, K. Y. Hammy

Dangerously high stress areas can be controlled by proper mine planning and/or destressing. This paper reviews practical methods to detect and destress high-stress zones along coal faces. The US Bureau of Mines investigated stress-related burst problems and destressing efforts at a cooperating mine. Laboratory tests of the drilling yield method for high stress detection were conducted to determine the correlation between the volume of cuttings obtained and the magnitude of the applied stress. A three- dimemiom1 computer modeling program was used to evaluate the effectiveness of stress relief methods.

Jan 1, 1987

By Noel C. Joughin, Orrie Fenn, Brian E. Protheroe

Work has shown that the use of high-pressure water jets enhances the performance of mechanical cutting in very hard rock. To assess the potential of this approach for use in conjunction with free rolling cutters, a series of tests has been conducted using both disc and button type cutters, to determine the relative effects, on cutter performance, of variations in relevant jet and cutting parameters. In these tests it was found that water jet assistance can result in reductions in the forces on a free rolling cutter typically of the order of 40%.

Jan 1, 1985

By Pamela J. Nebgen

Surface mine planning and watershed management requires the manipulation of a massive volume of data. The processes of collecting, examining, selecting, and generalizing information for the production of maps and sediment structure designs are a major part of mine planning and evaluation. Computer aided design graphics systems are becoming increasingly more important to the surface mining industry. This paper illustrates the applications of a digitizer and plotter interfaced to an IBM PC-XT microcomputer, which form the hardware elements in the new University of Kentucky hydrology, sedimentology, and structure design package called SEDCAD.

Jan 1, 1986

By C. D. Elifrits, N. B. Aughenbaugh

Laboratory tests of samples of fine- grained, argellaceous rocks, commonly referred to as shales, have shown that various changes in their moisture content can be correlated with loss of strength. This reaction to a change of in situ conditions at abandoned mine sites when combined with the field relationships at locations where the predominant overburden material is fine-grained, argellaceous, and fractured provides a predictive tool for engineers dealing with subsidence problems. Such a tool should enable engineers to recognize areas that are prone to be affected by surface disturbing subsidence features.

Jan 1, 1987