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By D N. B Skinner, R L. Brathwaite, M S. Rattenbury

The Institute of Geological and Nuclear Sciences Ltd has carried out a mineral resource assessment of the Coromandel region, one of the most mineral-rich regions of New Zealand. The assessment focussed on metallic minerals and clays, because these are the main commodities that have potential for increased production and export from the region (and from New Zealand).   Three steps were used in the assessment: 1) development of mineral deposit models, 2) comparison of the models with regional geology, structure, geochemistry and past mineral production to estimate the number of undiscovered mineral deposits, and 3) application of grade-tonnage models to determine the quantity and value of the known and undiscovered resources. In step 1, descriptive and grade-tonnage mineral deposit models were developed for 11 different types of mineral deposits: ò     Low-sulphidation andesite-hosted epithermal Au-Ag ò     Low-sulphidation rhyolite-hosted epithermal Au-Ag ò     High-sulphidation quartz-alunite epithermal Au ò     Porphyry Cu-Au-Mo ò     Andesite-hosted polymetallic veins adjacent to mineralised porphyry stocks ò     Zn-Pb-Ag skarn ò     Cu-Ag skarn ò     Hot spring Hg ò     Shoreline placer Ti ò     Rhyolite-hosted halloysite clay ò     Volcanic-related kaolinite clay   Step 2 was aided by a geographic information system (GIS) assembled from a number of digital spatial data sets including: a digital elevation model, an aeromagnetic map (from open file mining company data), a geological map (from the GNS QMAP project), location of areas of hydrothermal alteration, locations of mineral deposits (from the GERM database), stream sediment geochemical analyses (from the REGCHEM database), and a lineament map derived from satellite remote sensing data and the digital elevation model.   Based on May 2001 commodity prices, potential resources estimated for the 11 mineral deposit and grade-tonnage models total NZ$22 806 million for the metallic minerals, NZ$1000 million for halloysite clay deposits and NZ$57 million for kaolinite clay deposits.

Jan 1, 2001

By Steve Meador

West Virginia's basic coal mining regulatory programs are not unique when compared to Federally approved programs implemented by other coal producing states. In fact, the language in The West Virginia Energy Act governing subsidence mirrors that written in the Federal Surface Mining Control and Reclamation Act as well as other states' statutes. Certain legal and administrative issues, how¬ever, combine to make West Virginia's regulation of surface subsidence a singular approach.

Jan 1, 1986

By N. A. Hasenack

A full description of tests and test results of potgrate--as well as industrial tests is given. It is concluded that the favorable effects of magnetite ores on the pelletizing-plant results can almost be obtained by replacing the magnetites by hematites with coke breeze. The amount of coke breeze to be added should be about 30% above the theoretical value which is derived from the transition heat of the magnetite. The total amount of coke breeze should be limited to 1.5%.

Jan 1, 1977

By Wantae Kim

Ultrasonic stimulation of constituent suspension (metakaolinite/NaOH) can improve the rate of synthesizing reaction for zeolite Na-A. Zeolite Na-A can be synthesized from the suspension by sonicating treatment at comparatively shorter exposing time than conventional heating treatment. The main effect of ultrasound for the production of zeolite Na-A in the present heterogeneous solid/liquid reaction is intense stirring the solid and liquid substances to produce relatively narrow-sized zeolite Na-A particles with higher CEC value.

Jan 1, 2006

By Robert E. Haun

Retech's Plasma Arc Centrifugal Treatment (PACT) system is a thermal technology that uses heat generated by a plasma torch to treat hazardous waste containing metals and/or organics. Metal bearing solids and soil are melted by the process, and organic contaminants are thermally destroyed. The molten material forms a hard, glass-like leach resistant mass after cooling in a mold. This paper discusses plasma processing in general and presents some results of treating mineral processing wastes using the plasma arc centrifugal treatment process.

Jan 1, 1995

By H. H. Murray

New and improved beneficiation techniques are available to allow the production of clay minerals of exceptionally high purity. This is particularly true for kaolins and smectites. Wet processing techniques include particle size separation, high intensity magnetic separation, chemical leaching ,flotation, and selective flocculation. The blending of clay minerals with other minerals provides opportunities to make special ceramic materials such as cordierite and other minerals that have very special ceramic properties including low heat expansion, high fired strength, low absorption, and other desired qualities.

Jan 1, 1990

By Shonhardt JA, Bagster DF

This paper firstly examines the pollu- tion potential of burning colliery wastes. A comparison of two means of estimating the pro- pensity for coal to combust spontaneously is next presented. The use of microwaves, as a new procedure, is discussed in detail, while a comparison of the results is made with a modi- fied adiabatic technique. A number of coals that are known to combust spontaneously was tested, as were some coals that are not consi- dered to have self heating potential.

Jan 1, 1987

By Hayba DO

Metal-rich slurries discharged from excess-enthalpy geothermal wells at Kawerau (NZ) indicate that an efficient ore precipitation mechanism operates in some feedzones. In our conceptual model, which takes into account the relative permeabilities of liquid and gas phases in boiling fluids, a metal-precipitating liquid phase is effectively immobilised along boiling fronts, leading to the formation of highly concentrated ore. Chemical equilibrium and heat/mass transport modeling demonstrate the general applicability of this conceptual model to hydrothermal eruption environments.

Jan 1, 1995

By Thomas E. Brown

With the ever increasing public sensitivity to our environment, the blasting industry can no longer be concerned with just drilling and blasting. Government regulations, augmented by public pressure, require that the industry must be more diligent in preventing spills, disposing of distressed products and packaging materials, controlling fumes and dust, preventing product contamination, developing environmental impact studies, and preventing unnecessary regulations. These liabilities in conjunction with those of vibration, air overpressure and flyrock will continue to greatly impact the industry.

Jan 1, 1995

By William F. Riggs

The characteristics of frothers can often be determined by the proper selection of various chemical groups. There are three basic groups utilized in the application of frothers. These are alcohols, polyglycol ethers, and polyglycols. Some of the chemical groups are separated in subgroups. Each chemical group provides particular characteristics which affect load support, bubble diameter, water retention, air dispersion, and kinetics of froth formation. These chemical groups may be preblended in various percentages to optimize frother characteristics for a particular ore deposit.

Jan 1, 1986

By Michael Wieland

Three laboratory tests were developed for rating the wave-impact ruggedness of cap-sensitive explosives that are used for blasting in underground coal mines. Destructible pipe fixtures, called simulators, reproduce the shock wave or rift compression registered during the cross-hole wave interactions. The rift-compression fixture was modified to render quasi-static desensitization, when utilized with a remote air supply. Waves that were recorded near charge explosions show narrow pulses resembling underwater shock waves, followed by wide, weak humps, called rift compressions.

Jan 1, 1996

By M. J. McPherson

The legislation that prohibits the recirculation of air in coal mines was formulated because of the fear that concentrations of airborne pollutants would rise to dangerous levels. This paper undertakes a simple analysis of the effects of a controlled recirculation system on the gas concentrations in headings. It is shown, through an algebraic formulation and a numerical example, that a properly planned system of controlled recirculation leads to a reduction in the maximum general body gas concentration that occurs in a heading.

Jan 1, 1988

By J. M. Silliman

Several years ago, having occasion to determine the amount of some very slight atmospheric depressions, I devised and had constructed by a skilful tinsmith the manometer shown in the accompanying drawing. It consists of a cylindrical vessel of tin, 6.6 inches in diameter, through the sides of which, at a distance of about six inches from the top, passes an air-tube D, its upper extremity terminating 3.5 inches from the top. Within the vessel is a combined cylipdrical

Jan 1, 1889

By J. M. Mutmansky, T. K. Greer

This paper takes a look at the optimal velocity to be used in coal mine entries and determines a statistical relationship for optimal velocity that can be applied under current mining conditions. This relationship provides the optimal velocity for coal mine airways under variations in power cost, mining cost differential, airway friction factor, time value of money, airway lifespan, and quantity of air carried. This enables the ventilation engineer to make an easy, rapid determination of the optimal velocity for planning purposes.

Jan 1, 1985

By J. C. Ashby

Electric utility response to certain amendments of the Clean Air Act has resulted in a production of several types of alkaline coal combustion byproducts (CCB). Alkaline combustion byproducts are gaining increasing usage for acid mine drainage (AMD) mitigation as research leads to a better understanding of their beneficial applications. Since January 1997, Mettiki Coal has been injecting alkaline flue gas desulfurization material from Virginia Power's Mt. Storm Unit No. 3 wet limestone scrubber into abandoned portions of the active Mettiki Mine.

Jan 1, 1998

Progress on this project will be verbally reported and a description given of the main features. A detailed feasibility study was completed in December 1986, and the Joint Venture has issued an Environmental Impact Statement. This was open for public comment until 16 February. Issues presently being considered include economic justification traffic, air quality, noise, marine fauna and flora, visual impact, heritage and construction impact. Detail design and construction is likely to commence in mid 1987, following determination of the above matters.

Jan 1, 1987

By R. W. Van Dolah

The feasibility of formulating cap-sensitive slurry explosives for use in underground mines with potentially flammable gas atmospheres was examined. Formulations containing aluminum metal as sensitizer and sodium chloride to reduce incendivity were prepared; some were cap-sensitive and had adequate air-gap. Flaked aluminum metal rather than the atomized type proved to be the more effective sensitizing agent of the formulations tested for incendivity in the large gallery of the Bureau of Mines, some were found to be suitably nonincendive.

Jan 1, 1968

By Bruce See J

Oxidation of artificial Imperial Smelting Furnace lead bullion was performed during cooling between 1180 and 820°C in order to attempt to produce a tin-rich dross.The addition of sodium carbonate together with stirring increased the tin content of the dross when oxidation was carried out with air or PbO on zinc-free bullion.Zinc in the bullion during oxidation resulted in a decrease in tin concentration of the dross due to zinc oxidation and copper entering the dross.

Jan 1, 1987

By Sir Lowthian Bell

WITH the exception of air and water, it is open to question whether there is any form of matter which the human race could less easily spare than iron. Short of going the length of asserting that, without this metal for an anchor or steel for the compass, the adventurous navigator could never have crossed the wide Atlantic, we may credit the locomotive' and the steamer, and hence iron, for that sequence of events which has peopled North America with the

Jan 1, 1891

By Richard R. Marston, Scott Herr, Steve Pries, Donald L. Jr Ewart

The purpose of this paper is to identify and examine alternative methods (other than shovel/truck stripping) of effecting the pre-stripping of consolidated overburden, in conjunction with dragline stripping operations, at surface coal mines. The analysis will be case study oriented with practical mining considerations and comparative economics being evaluated. Alternatives that will be examined include blast casting, dozer push, and multiple pass dragline sequences.

Jan 1, 1992