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By Taylor R. N

Flow simulations have been performed on the flash-smelting burners currently used at KNS. This paper presents studies of the heat transfer between gas and particles at the burner exit. Gas and particle temperatures, velocity and concentration profiles of the two-phase flow are calculated by the mathematical model. The predicted gas temperatures have been favourably compared against values measured by thermocouples placed near the burners in the flash furnace. The predicted particle temperatures are also reasonable when compared with the measured temperatures.

Jan 1, 1992

By J. Richard Maier

Short-range mine planning (less than five years) previously was accomplished using contour and isopac maps, pencil and paper, an abacus, and our lucky quarter. Through the use of both micros and mainframe time sharing, Glenrock Coal Company (GCC) has been able to virtually put the old equipment away (except the problem solving quarter). In the process, GCC has saved many man-days and eliminated the more tedious parts of mine planning, such as picking elevations off a map with an engineer's scale and repetitive calculations. These savings have allowed GCC to do a more extensive job of mine planning as well as offer more alternatives, making GCC better prepared for possible economic changes. Mine planning, simply, involves looking at what has been done and deciding what needs to be done using various constraints. The application of this concept is not as easy as it sounds. The need for experience and insight cannot be replaced by a machine, but machines can supplement a person's ability by doing the bookkeeping and the repetitive work. Through the application of computers and their accessories, GCC has brought mine planning to a more modernized state. The following paper will detail the development and use of one system as used at GCC. Please note: In the figures and tables following, some of the data has been altered to protect confidential information used in mine planning.

Jan 1, 1983

By J. B. Zachwieja, P. E. Richardson, G. W. Walker

The electrochemical nature of mineral-collector interactions and their relationship to flotation have been investigated to develop a better understanding of the factors controlling sulfide mineral beneficiation. Spectrophotometric and electrochemical techniques have been used to examine the reactions occurring on electrodes composed of a bed of bornite particles in the presence and absence of potassium ethylxanthate (KEtX) at a pH of 9.2. The combined techniques showed that KEtX sequentially reacts with bornite by (1) a chemisorption reaction forming ca hydrophobic species between --0.4 and -0.2 V (SCE), (2) an electrochemical oxidation reaction forming cuprous xanthate between -- 0.2 V and the xanthate/ dixanthogen redox potential, and (3) oxidation to dixanthogen when the potential exceeds the reversible value for the xanthate/dixanthogen couple. The flotation response of bornite closely parallels spectrophotometric and electrochemical evidence for adsorption of KEtX by the reactions listed above. The degree of surface oxidation resulting from the formation of iron oxides on the surface dictates the flotation response as evidenced by the fact that oxidized bornite floats at more anodic potentials than unoxidized bornite. The strong correlations between the flotation response, degree of oxidation, and potential indicate that chemisorbed xanthate produces a hydrophobic layer sufficient to float unoxidized bornite, but cuprous xanthate and dixanthogen arc required to float oxidized bornite.

Jan 1, 1988

By John E. Sweet

THERE have already been so many subjects of a purely mechanical nature presented to the Institute of Mining Engineers, that it is unnecessary for me to apologize for adding another to the list. When a new invention, or what is supposed to be a new invention, claiming simply an improvement on the well-known devices, is to be described, it is usual to point out the defects of the old and give a history of the object or the art up to date. But, as no doubt a large proportion of the members of this Institute know as much, or more, about the history and use of the steam-engine indicator than I do myself, I will not further preface the subject, than to remind you that what called for the Richards's improvement on the Watt's indicator was high speed ; that the leading improvement was the reduction of momentum in the reciprocating parts; and that this was accomplished by making the parts lighter, and reducing the travel of the heaviest of them, and consequently the speed and momentum. The use of the indicator has been extended, for the speed of steam-engines and other prime movers has been increased, until one engineer at least, John Cooper, of Philadelphia, says, "I want an indicator that will work up to a thousand revolutions." Mr. Thompson, of the Buckeye Steam-Engine Company, of Salem, Ohio, has improved on the Richards's indicator by another reduction in the momentum, which is done by putting the parallel motion nearer the fulcrum of the pencil arm, reducing both weight and travel. The characteristic feature of the indicator I am going to illustrate is a still further reduction in the same direction, which is accomplished by dispensing with the parallel motion altogether. As is often the, case, in putting a simple idea into shape, some difficulties

Jan 1, 1879

By J. S. Johnson, W. C. McCulloch

All phases of plant operation must be synchronized so that the A number of interruptions in the flow of material may be reduced to a minimum. In the majority of plants operating under a labor agreement, time lost during the operating shift cannot be made up with overtime. With the work week restricted to 35 hr., the ratio of productive time to total time justifies extra effort in keeping the plant operating at capacity during the productive shift. This does not apply when central plants with adequate storage are operated by multiple shifts. In such installations the problems become similar to those of any factory or mill where added units, parallel circuits, or excess capacity serve to maintain the average production during intervals of maintenance shut- down. These plants, by special agreement, may run continuously, barring mechanical interruptions. The control of plant operation is in those procedures that are practiced to obtain from the run-of-mine product a high recovery of clean coal products to meet adopted trade standards and consumer specifications at the lowest possible cost. Correlation of all factors for continuous operation requires more than mechanical perfection in the plant. The run-of-mine coal must be delivered to the preparation plant without delays and the clean coal and refuse products taken away. Power supply and water requirements must be adequate. Signal systems must be established for emergency stops and to facilitate resumption of coal flow.

Jan 1, 1943

By Denholm W. T

The SMELT-2 package is specifically designed to perform on-line simulation of smelting processes. This paper describes its application to the simulation of continuous matte converting followed by reductive slag cleaning in SIROSMELT reactors. The matte, containing 50% Cu is assumed to be produced at the rate of 20 tph in a continuous matte smelting furnace such as an Outokumpu Flash Furnace, Noranda or Sirosmelt reactor. Two alternative fluxing strategies in the converter are examined, namely: ò conventional silicate slags, ò calcium ferrite slags, and the flow sheets associated with each strategy are discussed. A regular solution model is used in the present study to account for the variations in the activity coefficients of components in the slag.

Jan 1, 1989

By E. G. Davis

The flash reduction of fine iron ore in a dilute-phase system was investigated at 500° to 900° C within a heated stainless steel tubular coil. Alabama brown iron ore and Mesabi semitaconite ore were fed into the coil concurrently with reducing gases of hydrogen and reformed natural gas, so that the velocity of the gas at the reaction temperature was sufficient to entrain and pneumatically transport the solids through the coil. Reduction is very rapid with retention time of the ore in the coil varying from 4 to 15 seconds. Variables affecting reduction are temperature, ore feed rate, and gas flow or velocity. Results of the studies show that a partially reduced product (10-to 25-percent reduction) can be made which, on subsequent magnetic concentration, yields a concentrate containing 64 to 70 percent iron with a 90-to 94-percent iron recovery. Maximum reduction of 77 percent was obtained when hydrogen was used in a four-stage reduction test to yield a product containing 61 percent metallic iron.

Jan 1, 1972

By Wilson R. G

Mining conditions imposed by a coal seam roof can be analysed according to natural causes, before consideration of strata control. All types of roof behaviour can be explained by considering only three independent variables. They are roof rock types, rock stresses and discontinuities. Roof rock types encountered in the Sc.ithern Coalfield of New South Wales (NSW) are sandstone, shale, mudstone, laminite and coal. Each rock has its own mode of failure. Lithological stability of the sediments varies from one type to another. Regional stresses upon a coal seam roof will vary in magnitude according to the proportion of gravitational stress, which is related to depth of cover, and residual stress, which is related to the maximum depth of burial and may be gauged by coal rank. Local stresses will vary according to tectonic deformation, related to irregularities in seam structure.

Jan 1, 1976

By Cutmore NG

The moisture content of iron ore is important in handling, stockpiling, transport and further processing operations. Typically these ores contain both `free' and `bound' moisture, the latter being moisture that is not removed in a conventional laboratory determination of moisture by air drying at 105¦C, and it is the free moisture that is important in dust control and ore handling. The CSIRO Division of Mineral and Process Engineering has previously developed and commercialised gauges, based on capacitance and microwave techniques, for the on-belt determination of moisture in coal and minerals. However, these gauges determine total moisture, and have a different sensitivity to free and bound moisture in the material analysed. Consequently, the accuracy of determining total or free moisture alone may be significantly affected by variations in the bound moisture content. An investigation has been carried out on the simultaneous determination of free and bound moisture in iron ore fines (

Jan 1, 1993

By B. M. Larsen

Jan 1, 1965

By V Rajakumar, S Trang

Titanium has the potential to become the third wave of light metals used in high volume applications, following on from aluminium and magnesium. These light metals have functional attributes that can meet many of the goals needed for societyÆs transition to sustainable development. CSIRO has initiated a Light Metals Flagship to focus additional R&D efforts in support of the light metals industry. The vision of the Light Metal Flagship is for Australia to lead the Light Metals Age by reducing the costs and environmental impacts through innovative technologies for these metals. Life cycle principles will be used to identify novel technology pathways for metal production and product manufacture that are more energy efficient, less capital intensive and incorporating eco-efficient material flow chains.Under the auspices of the Light Metal Flagship, a Life Cycle Assessment (LCA) of titanium metal production was carried out with mineral sands mining of ilmenite as the starting point. Upgrading of the ilmenite to synthetic rutile by the Becher process and titanium metal production by the conventional Kroll process were the processing routes considered. Two alternative processes for titanium metal production, the FFC Cambridge process involving direct electrochemical deoxygenation of titanium dioxide, and a plasma process for producing titanium powder from titanium tetrachloride were also examined using LCA methodology and compared to the Kroll process. The environmental impacts included in the LCA were greenhouse gas emissions (Global Warming Potential, GWP) and acid rain gas emissions (Acidification Potential, AP). The Gross Energy Requirement (GER) of each process was also determined.These results for titanium, along with those from previous LCA studies by CSIRO on aluminium, magnesium, steel and stainless steel production, were used to show that despite the relatively large amounts of primary energy required for the production of these light metals, their special properties (eg corrosion resistance, strength and light weight) mean that these metals offer potential GER and GWP reductions compared to other competing materials in a number of applications, when viewed on a life cycle basis. Two applications considered in the paper are the lightweighting of motor vehicles and chemical plant equipment manufacture.

Jan 1, 2004

By J. L. Thompson

Lime made in a coal-fired rotary kiln has two distinct parts: the interior of the pebble which constitutes about 90% to 95% of the mass, and the surface dust layer which is the remaining 5% to 10%. Uncalcined carbonate and impurities in the product may be present and will not contribute to the hydration reaction. Sulfur, in the form of calcium sulfate, inhibits the hydration reaction out of all proportion to its actual weigh- percent concentration (perhaps more than 100 times). If the stone contains dolomite, this will also inhibit the reaction as its rate of hydration may be nearly three orders of magnitude slower than that of calcium oxide. Early in the hydration reaction dolomite appears practically intert, but given sufficient time, it will hydrate. The heat of reaction is nearly the same as for calcium oxide, but the time necessary for complete hydration may be hours; whereas for calcium oxide it is only fractions of a second. The dust layer on the surface also inhibits hydration as it contains a collection of compounds which have low heats of hydration. This layer can tie up additional calcium and delay or prevent its reaction. In addition to these chemical processes, an important physical characteristic of the lime is its specific surface area. This is effected by the thermodynamics of calcination and the original stone grain chemistry. All of these factors are agglomerated in the gross slaking rate of lime.

Jan 1, 1980

Do not write until you have something to say. Think first; then write. In order to be understood, you must know what you wish to say. Clear writing is the consequence of clear thinking. Therefore consider your subject well before you begin to write; ruminate on it; marshal the salient facts in your mind; saturate yourself with the ideas you wish to express and with cognate ideas; then express yourself deliberately. If you are bubbling over with your subject the words will come, but you might as well expect to sail without a breeze as hope to give life to words without the living thought. Here I may advert to the fact that among the uneducated it is a common expectation to acquire the knack of writing without taking the trouble to study the art of literature. I overheard a woman in a suburban train remark to her neighbor: "I'd like to be able to write well without stopping to think about it". She was one of many that would like to do a thing well without the trouble of thinking; but it cannot be done in respect of anything to which thought is essential. The possession of a good voice does not justify a person in expecting to sing successfully to a large audience; before singing in public one has to master the technique of singing; one has to learn first how to breathe properly, how to enunciate, and many other things. The successful singer is an artist, not a megaphone. Most of us would regard a man or a woman without any training in the art of singing as a fool or an impostor if he or she were to give a public concert, yet we do not recognize the equal foolishness and imposture of persons that write books before they have studied the technique of writing. That is why so many books are unreadable, and why many books by clever men are difficult to read. They start to write books before

Jan 1, 1931

Jan 1, 1923

By Szymanski J

Although efforts towards producing a `total quality rockfill product' have allowed cemented rockfill costs to be reduced considerably, there is still tremendous potential for further cost reductions. Cemented rockfill costs range from approximately $7 to $12 (US) per tonne of fill placed. Approximately 50 per cent of the rockfill costs are associated with cement costs. A large portion of the remaining 50 per cent is associated with labour and materials handling costs. Several Canadian underground mines utilise haulage trucks and/or conventional belt conveyors to distribute the rockfill. However, due to the restrictive nature of the underground environment, these current materials handling systems have limitations (ie spillage from trucks, dust from conveyors). The Sicon conveyor system (developed in Sweden) has considerable potential for replacing these current methods. The Sicon conveyor utilises a revolutionary approach - the conveyor belt is folded over upon itself (forming a tear drop shape) so that the transported material is completely encased within the belt. The Sicon conveyor's ability to negotiate very tight comers (without transfer points) makes the conveyor very appealing for underground mining applications. An analysis comparing the pros and cons associated with the Sicon conveyor system versus conventional materials handling systems will be presented in this paper.

Jan 1, 1995

By Campbell R

The use of a 35mm non-metric SLR camera and an analytical plotter to prepare close range photogrammetric (CRP) plans of a quarry and open pit mine face is described. The plans, at scales ranging from 1:5 -1:1 000, were used to measure the orientation of geological structures and failure surfaces in the exposed faces.Details are provided on the equipment used and the field techniques. The method:ò is quick and relatively cheap to perform,ò allows the accurate orientation of specific geological features to be determined,ò provides survey results of suitable accuracy that may be used for detailed geotechnical analyses of pit wall failures,ò shows great potential as a rapid and accurate technique for monitoring changes in pit wall profiles with time.

Jan 1, 1990

Problems associated with gas management become more significant as exploitation of coal reserves in the Bowen Basin in Australia becomes deeper. At Oaky North mine, relocation of production from one area of the mine to another with a higher gas content required the use of pre-drainage, post drainage and inertisation techniques to enable production activities to continue largely uninterrupted. Innovative surface to inseam drilling techniques were developed for pre-drainage of reserves close to mine workings and have proven to be largely successful. The gas management techniques adopted and specific experience gained are discussed in this paper.

Jan 1, 2005

By Eyers G. C

Long Shaft was initially developed using a rail haulage system on every working level comprising battery electric locomotives and granby trucks loaded by rail mounted rocker shovels. Production was commenced using conventional hand held cut and fill mining methods. In an effort to improve productivity and reduce operating costs a mechanised cut and fill stoping method evolved to suit the wider sections of the orebody. To further improve productivity and reduce costs the mechanised levels of the mine are progressively being redeveloped to enable the use of trackless diesel haulage equipment. An added benefit of trackless haulage equipment will be the ability to place development mullock into stopes as Fill.

Jan 1, 1988

By Chenggang W, Junhua D

Fragmentation variation laws in loading and non-loading areas are obtained by cement block model blasting experiments under various stemming lengths. A reasonable ratio between loading length and stemming length is worked out according to minimum average fragment size. The present continuous loading structure, for its very long length to be stemmed, leads to insufficient fragmentation in the upper part of bench. So a new loading structure with bottom air cushion is put forward. The author analyzes blasting effects and processes of two loading structures' and proves that there exists a optimal length of air cushion.\

Jan 1, 1990

Deposits of chromite are in associated with ophiolite complexes in Papua New Guinea. No deposits which are currently exploitable have been recognised, but large resources that may be economic in the future are present at Ramu area and on the Morobe coast. These are contained either in laterites or in sediments derived from ultramafic members of the ophiolites. There are possibilities of establishing further resources either in similar settings or associated with ultramafic members of alkali intrusive Complexes.

Jan 1, 1987