Search Documents

By G. Azimi

Calcium sulphate precipitation, mainly as gypsum, during neutralization of acidic hydrometallurgical process solutions can lead to excessive scaling problems. In this work, a self-consistent fundamental chemical model is presented based on the OLI software platform. The model employs the new Mixed Solvent Electrolyte (MSE) activity coefficient model of OLI. A thermodynamic database has been developed and calibrated on experimental data from metal sulphate solutions. The model predicts very well the solubility of calcium sulphate within a wide temperature range and can be used to assess the scaling potential of a particular process stream composition. The effect of temperature, acidity, and divalent metal concentration on the solubility of calcium sulphate in multi-component process streams is also simulated and discussed.

Jan 1, 2006

In-seam drilling is conducted mainly to drain coal of gas and/or water prior to development or extraction. The requirements of inseam drilling for gas drainage have mainly surpassed the technical limits of rotary drilling and are mainly being addressed by guided down hole motor drilling, albeit at a higher cost. There is an increasing application of in-seam drilling to detect geological structures or other hazards or their absence in advance of mining to reduce the risks of underground mining. Close collaboration between miners, drillers, geologists, researchers and suppliers over the last four years has seen many advances made to improve the accuracy and reliability of inseam drilling. With such developments will come closer control over the ventilation and safety of future mining under deep gassy conditions, but not without costs. The paper summarises the current applications of inseam drilling, recent technological advances and the next generation survey and geophysical sensing tools which are currently being developed

Jan 1, 1998

By Wayne D. Gould, Terry O. Arney

The Pinto Valley digital control system is a supervisory system interfaced with a conventional analog control system. The design criteria, the hardware selection, and the startup of the system in the Pinto Valley concentrator are reported in depth. Examples of data collection application, as well as the present and immediate future implementation of control strategies, are discussed. This paper is a description of the digital data acquisition and control system that is installed at Cities Service's Pinto Valley concentrator.

Jan 1, 1978

By Sinha NH

ICI Australia and CSIRO have developed a novel process for extraction of zirconia from zircon sands. The two stage process involves a high temperature step and a wet chemical processing step. A pilot plant has been operating since November 1985 at CSIRO Division of Mineral Chemistry, Port Melbourne and construction of a full scale plant isplanned at Kwinana, WA.The plant has a high degree of flexibility and is capable of producing high purity zirconia up to about 99.99% and withinspecific particle size ranges. The products are being marketed by the joint company, 2-TECH Pty Ltd.

Jan 1, 1986

By J. R. Palmes

Flocculation of coal fines with varying degrees of wettability was studied under well defined hydrodynamic conditions. In this study, three coal samples were tested with three different flocculant types. The results revealed that flocculation depends strongly on both the coal surface properties and the type of flocculant used. A hydrophobic flocculant was found to be effective for hydrophobic and slightly oxidized coal, a semihydrophobic flocculant was found to flocculate, to different extents, all of the samples except the oxidized cool, and polyacrylimide flocculated all of the coals, which is a clear indication of its insensitivity towards coal wettability.

Jan 1, 1994

By W. T. Ruhmer

Slimes-dam construction in the gold mines of the Anglo American Group by w. T. RUHMER. Pr.Eng.. B.Sc. Eng. (Met.) (Fellow) Current practices generally in accordance with the principles of design and operation of slimes dams within the Gold Mining Division of the Anglo American Corporation are described. Although many of the details given are either obvious or have been amply dealt with elsewhere, these have been included for the sake of completeness. The selection of suitable ground for the deposition of slimes, the initial design and construction of a slimes dam, and its consequent operation are presented in logical sequence. Emphasis is placed on the code of practice for the construction of slimes dams issued by the Chamber of Mines of South Africa, and draft regulations (Water Act of 1956) dealing with pollution. Operating costs are included, and possible future trends are discussed.

Jan 2, 1974

By Salah A. Taqieddin

The blast casting technique of removing overburden is an innovative technique which was successfully used in the mining of certain surface coal and quarries. This method was found to be efficient in minimizing the labor and equipment cost while accelerating mining operation with safety. This method was successfully applied to horizontal as well as to dipping coal seams. Also it was practically applied to single as well as to multiple ore bodies

Jan 1, 1992

By R. J. Batterham

This paper sets the scene for the Australian-Asian Pacific Course and Conference on Pyrometallurgy for complex materials and wastes. The relentless presence of competitiveness is rehearsed as the source of the current trends towards continuous improvement and benchmarking. While this might be expected to lead to more spending on pyrometallurgy, the opposite appears to be the case. The paper examines the reasons and suggests that we face an increasing challenge for selective developments that can lead to sustainable competitive advantage - both in mineral and in waste processing.

Jan 1, 1994

By L. M. Bigler, J. L. Dobra

With the passage of Mexico's Mining Law in 1992, the tax treaty with the US in the same year, and the passage of the North American Free Trade Agreement, gold mining for non-Mexican mining companies in Mexico has changed dramatically. The statutory changes have created an opportunity for non-Mexican precious metals' producers to own 100% of a Mexican gold concession. This paper examines the financial feasibility of a hypothetical gold mine and processing plant in Mexico. The analysis includes the operational consequences of the recent weakness of the peso, as well as tax and employment issues.

Jan 1, 1996

By Edmundo Alfaro

The paper describes the thiosulfate process for gold leaching like the best non-polluting alternative to cyanide. Thiosulfate is a non-toxic lixiviant and has the ability to complex gold and silver. Copper bearing ores are not harmful for the process and does not suffer the preg-robbing phenomenon like in the case of cyanide. Nevertheless, the process is not fully developed, basically because of the poor understanding of the solution chemistry. Upon thermodynamic considerations and experimental evaluations it was found that the system is unstable; thiosulfate oxidation is unavoidable and ammonia is lost by evaporation. Measures to reduce thiosulfate oxidation include the adequate balance of ammonia and thiosulfate concentrations, adequate pH, additions of sulfite and additions of complexing agents like glycine.

Sep 12, 2005

By R. W. Reisinger

An historic underground copper mine in Wyoming is discharging neutral but copper-laden water into a pristine creek. The EPA-deferred site qualifies for reclamation by the Wyoming Abandoned Mine Land (AML) program. The cleanup goal is to restore the discharge so that the creek can eventually support a trout fishery. Hydrological and geochemical investigations underground have suggested two sources of mine water: one clean and the other containing copper. Results of bench-and pilot-scale tests support the viability of using low-cost passive treatment techniques to reduce copper concentrations in the near-freezing mine discharge.

Jan 1, 2000

By Timothy P. Smirnoff, Anthony Stirbys, Amanda Elioff

The construction of the continuing expansion of the Los Angeles Metro System has required the construction of eight new station structures. One contractor proposed, as a construction alternative for the support of excavation of the Hollywood/Vine Station, the use of soil-mix walls instead of the conventional soldier piles and wood lagging. Soldier piles and shotcrete or wood lagging support systems had been generally used on the other sub-way station excavations constructed to date throughout the system. Immediately east of that station and in almost exactly the same geology, the Hollywood/Western Station was being excavated at the same time using a conventional support system. This paper com-pares the performance of these two support systems in the alluvial soils of the Los Angeles Basin.

Jan 1, 1997

By Jerry R. McGaha, Joseph A. Dos Santos

The favorable economics of conveyor based haulage, especially in moving large volumes. has long been acknowledged. This has given impetus to significant developments over the last two decades in conveying systems and equipment. Such developments have resulted in improved equipment and system reliability, versatility and mobility. The present writing presents conveyor systems and their variations. Long overland conveyors of various profile and plan layout are considered along with various typical support systems. This includes discussion of horizontally curving, two-way and booster driven conveyors. High Angle Conveyors-[HACs] are reviewed, citing in-pit as well as plant application. Finally, several important advances in idler and in pulley design are presented.

Jan 1, 1989

By S. Inaba, K. Taguchi, T. Uenaka, I. Mizuguchi, K. Umeji, H. Isako

At Kobe Steel Ltd., various improvements in pellet quality have been carried out since beginning lime-fluxed pellet production. Especially, dolomite-fluxed pellets, developed in 1975, have superior high temperature properties. With this improvement, successful BF performance has been achieved. But, in order to achieve more successful BF performance, improvements of physical properties such as the shape factor, reposed angle, and the bulk density are desired. Now, crushed pellets have been developed for the improvement of those characters. The test operation with these new pellets in Kakogawa No. 2 BF was carried out with successful results. This report describes the development of crushed pellets and their use in BF.

Jan 1, 1986

PERSONAL (Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who registered at Institute headquarters during. the period May 10 to June 10, 1915: Robert M. Keeney, Somersville, Conn. C. A. Moffett, Birmingham, Ala. Emilio Mosonyi, San Salvador, C. A: A. W. G. Wilson, Ottawa, Canada. Junjiro Nagazumi, Fukuoka, Japan. G. H. Glover, Jr., Short Hills, N. J. Francis R. Pyne, Elizabeth, N. J. R. W. Brock, Vancouver, B. C. F. C. Alsdorf, Los Angeles, Cal. J. L. W. Birkinbine, Philadelphia, Pa. W. J. Loring, London, England. Roy H. Allen, Jamesburg, N. J. R. A. Bull, Granite City; 111. Francis Andrew Thomson received the degree of Master of Science from the Colorado School of Mines at the recent commencement exercises. The subject of his thesis was Stamp Milling and Cyaniding.

Jan 7, 1915

By L. T. Larson, P. M. Basinski

In the northern Reese River Valley uranium is corroded with Middle Pliocene zeolites. These zeolites were diagenetically derived from rhyolitic volcanic glass deposited in a saline- alkaline lake. X-ray diffraction, scanning electron microscopy, and chemical studies reveal clinoptilolite, analcime, and enonite to be pesent and that these minerals can concentrate at least 0.7% uranium from solution. Most anomalous drill cuttings contain zeolite and zeolites are believed to host the uranium. Research suggests the uranium mineralization is conceptually analogous to the Tono mine, Japan.

Jan 1, 1981

By J. C. Stankus, S. S. Peng

Many coal seams are associated with soft floor strata. During mine development, if coal pillars are not properly designed, floor heave occurs and causes interruption of coal production. In the severe cases, the section or mine is abandoned. One method for controlling floor heave is floor bolting. This paper describes the demonstration of flour bolting methods in a West Virginia, info coal mine. Three methods were used: vertical full resin bolting, floor truss bolting and floor truss bolting pins a floor slot at the center of the entry. The design of each method and the experimental results are discussed.

Jan 1, 1995

An extensive study was carried out to evaluate the performance of Outokumpu OK50, OK38 and Maxwell MX14 cells at ComincoÆs Red Dog flotation concentrator in Alaska. Tests were conducted by varying operating conditions of the cells installed in different circuits in the plant. The hydrodynamic and gas dispersion properties were measured and the metallurgical performance of the cells was evaluated for each condition used in the tests. This paper highlights the importance of superficial gas velocity, bubble surface area flux, gas hold-up, power consumption, residence time distribution and froth flow behaviour in optimising cell performance. The findings of these tests provide valuable insights into selection of the best cell operating conditions to optimise circuit performance.

Jan 1, 2000

By Koehler S. Stout

At today's mineral prices, unproductive or low productive work in any underground mine must be kept at a minimum to insure a profit. Improper level and raise spacing can be one of the contributing factors to high production costs, and little can be done to reduce these costs after the spacing interval has been chosen. The objective in selecting level spacing is to find the most desirable interval which produces ore at the least cost per ton while still operating within the highest margins of safety and efficiency to the workmen. In addition, maximum possible recovery of ore under the conditions must be attained.

Jan 11, 1962

By Francis O. Otuonye

A time series and system analysis modeling technique was applied to signals from strain egages mounted on a fully grouted resin roof bolt and signals from accelerometers mounted on the bolt head and roof rock to determine the roof bolt's response to repeated blast loading. The derived model gives a comprehensive quantitative description of the modes of vibration of the roof bolt response to each blast loading. The damping ratios and natural frequencies of the modes of vibration can reveal the alteration of the process dynamics due to the deterioration of the roof rock and can be used to identify the incipience of instability in the roof bolt system.

Jan 1, 1987