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By D. Preece

The mining and oil industry employs techniques such as geologic mapping, core drilling and electromagnetic and potential field techniques to explore for new deposits. Since new discoveries of major near-surface ore bodies are becoming progressively rare and since traditional exploration methods are unable to resolve ore bodies deeper than about 500m, high-resolution seismic reflection techniques show great potential for exploration to much greater depths down to almost 3km.

Jan 1, 2011

By Charles W. Henderson

THE influence of mineral production on the development of the western United States has been profound. From 1848 to 1860, there was only gold production, the effect of silver began in 1860, and from then on both had a powerful influence. Lead production started in 1863, copper in 1863, and zinc in 1885, but was small until 1898. Gold alone was therefore the stimulus of the early settlement and exploration of the Western States.. But mineral deposits caused neither acquisition of territory nor determination of boundary lines. Arizona, California, Nevada, New Mexico, and parts of Utah, Wyoming, and Colorado were formally acquired from Mexico fourteen days after the actual date of the discovery (January 19, 1848)1.2 of gold at Sutters Mill, near the present town of Coloma, California (a discovery which, with the immediate new discoveries, aroused the world several months later) ; but the acquisition was by treaty (under negotiation for some time but signed February 2, 1848)3 in settlement of a war involving the boundaries of the grassy plains of Texas, an area at that time not known to contain any metals, and to date found to have but few metal deposits.4 The international boundary at 49º latitude for the far northwest states was determined by causes other than mineral deposits.

Jan 1, 1933

By Xiaochun Xiao, Xin Ding, Yishan Pan, DI WU, Xiangfeng Lv

Rockburst is a sudden disastrous instability of coal mass that poses a serious threat to underground exploitation of coal resources; therefore, approaches of prediction and control methods are valuable for improving mining environments. The mechanical properties and bursting liability of coal with drying, under-saturated, and saturated moisture content under uniaxial compression are investigated, and the charge induction signal during coal deformation both in the laboratory and on-site is recorded in this study. The presence of water reduces the cohesion and increases the internal stress caused by non-uniform deformation of minerals, resulting in the strength, elastic modulus, and bursting liability being weakened. The charge induction precursor main frequency band is 1–100 Hz and belongs to the very-low-frequency signal regime, and it indeed varies with the loading stage, leading to specimen failure owing to changes in amplitude and continuity of the charge pulse in both the time and frequency domains. Water inhibits the richness of charge induction and reduces the bursting liability, and the earlier the precursor appears, the more total charge emerges. Moreover, measurement results indicate that the amplitude and continuity of the charge pulse decrease over a longer time, as recorded in a coal seam with water injection, further verifying the weakening of the coal dynamic characteristics. Charge induction can be a valuable tool with which to obtain the precursors for rockburst and to aid the evaluation of water injection.

Dec 26, 2022

By William P. Roe, James F. Ellis, W. P. Fishel

This paper reports the distribution of sulphur between iron and titanium in Fe-Ti-S alloys and in Fe-Ti-C-S alloys. The compound TiS was found, which exists as a separate phase at temperatures below 1200°C. Titanium in steels reacts with sulphur in preference to carbon. THE general relationship between sulphides and oxides suggests that titanium should form a sulphide having properties similar to those of titanium oxide. Specifically, titanium should form a sulphide having a high melting point, indicating a stable compound of low solubility in iron. In order for titanium to function as a desulphurizer or sulphur-fixing agent, it must form a stable sulphide. In order for titanium to be useful in steels as a sulphur-fixing agent, it must react with sulphur in preference to carbon; and to prevent red shortness, the sulphide formed must have solubility characteristics such that grain-boundary precipitation of a low melting phase be prevented. The terms desulphurizer and sulphur-fixing agent when used in this paper mean that titanium effectively ties up the sulphur as a stable sulphide of titanium and prevents the formation of FeS. The partition of sulphur between iron and titanium was studied first in a series of Fe-Ti-S alloys with carbon absent, and then in similar alloys with carbon present. It has been established1 a that titanium forms in Fe-Ti-S alloys a sulphide of undetermined composition which can be identified microscopically, and that the titanium-sulphur compound does not respond to sulphur printing. It has been suggested" that titanium acts as a sulphur-fixing agent, although little proof has been given. A report% f The Advisory Committee on Metals and Minerals summarizes the existing knowledge concerning substitutes for manganese in steels. Distribution of Sulphur Between lron and Titanium with Carbon Absent The alloys for this investigation were made by -melting Armco iron, metallic titanium, and iron sulphide in alundum crucibles in an induction furnace. The titanium was added after the other ingredients had melted. In these alloys it is recognized that some TiO, is present, since the melts were made in the air and since no other deoxidizing agent was used; therefore, some of the titanium was not available for union with sulphur. Thirteen ingots were made. Ingots 2 to 8 were cast in baked-sand molds; ingots 12 and 13 were cast in metal molds; and ingot 9 was allowed to cool in the crucible in which it was melted. All ingots were annealed at 900°C for 3 hr and were cooled slowly in the furnace. Subsequent information indicates that this anneal had no effect upon the titanium sulphide particle size, since the sulphide does not go into solution at this temperature. The ingots as-cast were approximately 8 in. long and % in. diam. The compositions of the eight ingots and the results of the partition of sulphur are recorded in Table I. Total titanium and total sulphur were determined by standard gravimetric methods. Sulphur, as iron sulphide, was determined by the evolution method. Boiling HC1 (1:4) liberates the sulphur from iron sulphide, but leaves the titanium sulphide practically undecomposed. A complete separation of titanium sulphide and iron sulphide cannot be made by digesting these compounds in dilute HC1 since titanium sulphide was found to dissolve slowly. The amount of titanium sulphide decomposed will depend upon the time in contact with the acid and upon the particle size of the sulphide. The point

Jan 1, 1952

By W. E. Roscoe

"Mineral exploration properties are those on which an economically viable mineral deposit has not yet been discovered. Such properties are bought, sold, optioned and joint ventured on the basis of their perceived potential for the existence and discovery of a viable mineral deposit. The intrinsic value of an exploration property is therefore based on the exploration potential. One measure of the exploration potential is the amount that can be justified to spend on exploration for a viable deposit.The appraised value method uses a cost approach to value exploration properties. It is based on the premise that an exploration property is worth the meaningful past exploration expenditures plus warranted future costs to test remaining exploration potential. Results of past exploration work are analyzed in order to retain only those past expenditures that are productive in terms of identifying remaining potential. Warranted future costs comprise a reasonable exploration budget to test that potential."

Jan 1, 2002

By Gregory J. Chekan

The U.S. Bureau of Mines is investigating longwall panel and gate road layouts to increase coal recovery and reduce multiple-seam interactive problems. This report presents design practices for longwall mining multiple seams to provide mine planners and operators with practical guidelines for designing productive longwall mines. Key aspects of mine design that control longwall interactions are examined, including sequencing of seams, design of gate road pillars, and orientation of gate roads and longwall panels. Theories that describe stress transfer between multiple scams and the mechanics of interaction are addressed in relation to geology. Common longwall designs were further investigated using a boundary element model, MULSIM/NL. The model provided insight into relative stress transfer and distribution that occurs between longwall operations in multiple seams. Findings from the model show that (1) a longwall panel should be mined from the gob to the solid coal of an overlying mine, because the stress concentrations are lower; the approach angle should be kept under 30°; and (2) when mining in descending order, superpositioning gate roads usually produces the worst stress condition. To prevent this, the overlying isolated gate roads should be positioned from the centerline toward the headgate side of the underlying panel.

Jan 1, 1993

By Fathi Habashi, Michel Pagé, Farouk T. Awadalla

"Chrysotile asbestos can be dyed with certain dyestuffs to form stable coloured products whose hemolytic and cytotoxicity are greatly reduced. Examples of these dyes are Thiazol Yellow G (a monazo dye) and Trypan Blue (a diazo dye). Other dye stuffs, for example, basic dyes with triphenyl methane structure, Brilliant Yellow (a diazo dye), and Methylene Blue (a thiazine dye) colour asbestos but do not reduce its toxicity. Similarly alizarin, 8-hydroxyquinoline, and representative members of the phthalein group Bromocresol Purple and Phenolphthalein.IntroductionThere is, at present, a controversy regarding the dangers of asbestos fibres, and attempts are being made to render it less toxic. One of these attempts consisted of treating chrysotile asbestos with gaseous phosphorus oxychloride, POCI], at ambient temperature and in absence of moisture. The product had to be heated at 300°C to 500°C to expel exess entrained reagent to get a material containing 0.5070 to 5% phosphate groups and known as Chrysophosphate (Lalancette and Dunnigan, 1982). This product showed decreased toxicity as measured by its hemolytic effect on red blood cells (fable 1). In another approach, Flowers (1983) showed that when chrysotile asbestos was thoroughly mixed with a solution of ferric ammonium sulphate and the slurry was then filtered and dried, the product showed a marked decrease in cytotoxicity.In the present investigation the problem of toxicity was considered from a different point-of-view. Chrysotile asbestos is a hydrated magnesium silicate that can be represented by the structural model shown in Figure 1 from which it can be seen that magnesium hydroxide groups, Mg(OH)2, form a part of the silicate structure. Certain organic reagents that are known to react with magnesium ion in solution to form chelates were reacted with asbestos to find out whether a chelate was also formed on the fibres, and if so , what will be the hemolytic action and cytotoxicity of the product."

Jan 1, 1991

By G. Grassmück

The question of whether the air curtain principle could be used under conditions prevailing in Canadian metal mines was investigated. A vertical, portable BERRY air curtain was tested, at first in a wind tunnel built at Ecole Polytechnique at full scale (8-by 8-ft cross section) to simulate a drift and its lateral connections, and then in the haulage ways of a metal mine under actual conditions. The results permit us to predict under what conditions this type of air curtain is capable of acting as an air stopping or flow regulator and how it could be further developed.

Jan 1, 1969

The Mount Morgan eopper-gold orebody is contained within a series of Mid-Devonian volcanics which occurs as a roof pendant within Permian granite. The ore minerals comprise pyrite, chalcopyrite, and local aggregations of magnetite and pyrrhotite. Silver-rich gold (electrum) is disseminated through the ore usually in ultrafine to sub-microscopic dimensions. Accessory minerals include marcasite, digenite, chalcocite, covellite, sphalerite, bismuthinite, molybdenite, calaverite, petzite, and cassiterite.Very minor accessories include cubanite, tetrahedrite, galena, arsenopyrite, hematiIe, goethite, and rutile. The gangue minerals are quartz, predominantly, with minor amounts of chlorite and sericite.Study of microtextures of a representative suite of specimens from Mount Morgan does not reveal any criteria indicative of metasomatic replacement but does show, in the case of pyrite, evidence strongly suggestive of annealing recrystallization. Other textures in pyrite indicate porphyroblastic growth of the iron sulphide.It is inferred that the Mount Morgan orebody is genetically related to the volcanic rocks and was later contact metamorphosed by the intrusive granite or by the series of intermediate to basic dykes that transect inmine area. On this basis the Mount Morgan orebody would be a contact metamorphosed volcanic hydrothermal deposit emplaced, according to recent studies, along a pipe-like zone of brecciation.

Jan 1, 1967

By Maria Amélia Martins

Os aços inoxidáveis duplex (AID) possuem uma estrutura austeno-ferrítica de aproximadamente 50% de cada fase, tal característica confere aos AID propriedades mecânicas superiores aos aços inoxidáveis ferríticos e austeníticos e elevada resistência à corrosão. Esses aços possuem uma adição significativa de elementos de liga, que são os responsáveis pelo correto balanceamento das fases e asseguram as propriedades desejadas. Outro parâmetro importante para assegurar as propriedades desejadas é o processamento termomecânico. Sendo assim, este trabalho avaliou a influência de diferentes temperaturas de tratamento térmico de recozimento nas frações de fases primárias (ferrita e austenita) e nas propriedades mecânicas de dois AID (UNS S32304 e UNS S31803). Os tratamentos térmicos de recozimento foram realizados em cinco temperaturas diferentes com tempo de encharque fixo seguido de um resfriamento rápido. A quantificação das fases primárias foi realizada através de microscopia óptica (MO) e as propriedades mecânicas avaliadas em um ensaio de tração uniaxial. As frações de fases primárias medidas indicam que com o aumento da temperatura de recozimento há aumento na fração de ferrita e a temperatura onde a microestrutura é mais aproxima de 50% de ferrita e 50% de austenita foi em 1020°C em ambos os AID. Além disso, observou-se que com o aumento da temperatura e, consequentemente da fração de ferrita, houve uma redução no limite de resistência nos dois AID deste estudo.

Aug 17, 2017

By A. Warczok, C. M. Diaz, A. Bergman, T. Utigard, M. Barati

The world wide consumption of energy is steadily increasing and by 2030 it is forecasted to grow by another 50%, leading to mounting political and economic pressures. For any pyrometallurgical operation, it is therefore paramount to investigate and implement methods to decrease the use of energy. In the pyrometallurgical processing of steel, copper, nickel and other high temperature metals, a large amount of energy is lost in hot off-gases, molten slags, mattes and molten metals. Most of this energy is generally lost during the cooling and solidification steps with very little focus on energy recovery or reuse. In this paper we will quantify how much energy is contained in the various slag streams, then review previous attempts and methods employed to recover some of this energy, and finally evaluate some novel technologies that could potentially be employed.

Jan 1, 2011

By Cleiton Rodrigues de Vasconcelos, Elizeth Oliveira Alves, Kleber Gonçalves Bezerra Alves

Em virtude da periculosidade do Pó de aciaria (PAE), práticas alternativas, como a reinserção do resíduo no processo produtivo, ou sua incorporação em outros materiais fizeram com que a reciclagem tenha se tornado uma via para este subproduto. O presente trabalho tem como objetivo identificar as áreas de desenvolvimento tecnológico de utilização do PAE, avaliar a potencialidade de reaproveitamento e reciclagem do resíduo oriundo do processo de produção do aço carbono, comparando as características obtidas do PAE analisado com os requisitos indicados através da análise de patentes. O PAE produzido no estado de Pernambuco foi caracterizado pelas técnicas de Fluorescência de raios X (FRX), separação granulométrica via peneiramento, distribuição do tamanho de partículas, Difração de raios X (DRX), Microscopia eletrônica de varredura (MEV) e Espectroscopia por energia dispersiva (EDS). A prospecção tecnológica foi realizada nas bases de patentes europeia EPO e na base nacional de patentes nacional do INPI. As análises realizadas mostraram que o material apresentou aproximadamente 28,5% de suas partículas com granulometria inferior a 53μm, composto em sua maioria por ferro e zinco presentes na forma de óxidos, organizados nas fases franklinita, zincita e magnetita. A baixa granulometria e composição química possibilitam a sua aplicação no campo dos materiais cerâmicos, bem como sua reinserção no processo de fabricação. O resíduo estudado apresentou características similares com os demais resíduos observados nas patentes.

Mar 1, 2019

By G. Lodewijks

This paper explores the savings that can be achieved in the energy consumption of belt conveyors used in mines by changing the conveyor components, the operational parameters of the system or the belt properties. First the concept of energy savings is introduced by looking at the energy consumption of belt conveyors from a theoretical point of view. Also methods for the calculation of the power consumption of a belt conveyor and the associated emissions are presented. Two case studies are presented in which the effects of the change of the operational parameters of the system, in this case the belt speed, and the belt properties, in this case the application of aramid products in the belt, are presented.

Aug 1, 2013

By W Patton, I Minniakhmetov, H Talebi, U Mueller

The sustainability of mining projects is linked to informed investment decisions based on public reporting of exploration and mineral resource estimation results. In Australia, public reporting guidelines are established by the Joint Ore Reserves Committee reporting code through the JORC Code (2012). Although the assessment of uncertainty in the results reported is a requirement, this is often communicated qualitatively and evaluated subjectively. This can become a liability particularly in the early stages of mining projects when spatial domains of geological interpretation and mineralisation envelopes inform resource estimations’ reliability. A recent review of JORC reports found no reports used quantitative assessments of the geological interpretation or mineral resource estimation envelopes, and 27 per cent of reports did not address the question of quality of geological interpretation. Reports that did address the quality used 19 different terms to communicate quality. This work presents methodologies for quantitative uncertainty assessment and communication and explores how they could be applied in public reporting practice. Quantitative uncertainty reporting would benefit mine planning and financial modelling as they normally assume the geology is 100 per cent right (since no error is reported or only a single deterministic model is provided). The complexity, cost, and additional work of doing a quantitative assessment could hinder a straightforward implementation. This could be overcome if mining companies budget for quantitative uncertainty assessment and associated professional development. A compulsory requirement for the inclusion of uncertainty assessments in public reporting or adopting standardised subjective language would improve industry practice.

Mar 22, 2022

The major factors limiting the establishing of vegetation on the shale and sandstone wastes at Minto are high exchange acidity and low pH (shale pH 4-5, sandstone pH < 4). In the first revegetation program (1967-74), 3.8 million trees were planted without grading on 4,000 acres (red, jack and scots pine and black locust). White dutch and sweet clover, birds-foot trefoil and red top were established in selected areas, and ponds were stocked with brook trout. In the second phase of reclamation, beginning in 1979, a comprehensive plan will be initiated which will allow for forest production, wildlife development and recreational activities.

Jan 1, 1977

By George Weaton

Two years ago the general features of the St. Joseph Lead Company&apos;s zinc-smelting process were described.1 At that time the discussion was limited to a description of the production of high-purity electrothermic zinc oxide. The present paper will describe the commercial production of electrothermic zinc metal. Since a fairly complete description of the plant of the Josephtown smelter was given in the earlier paper, the brief recapitulation given here will be limited to mention of additional equip-ment recently installed and a bare outline of the preparatory process. The raw material is zinc sulphide concentrate received from the com-pany&apos;s mines in St. Lawrence County, New York. An average dry-weight analysis of this material is: Zn, 58.28 per cent; Pb, 0.56; insoluble, 1.6; Si02, 1.12; Fe, 6.4; CaO, 0.47; MgO, 0.27; S, 31.9; Cd, 0.1; Cu, 0.06; Mn, 0.24. Moisture content is usually about 3 per cent. Three 21-ft. 6-in. diameter, 12-hearth Nichols-Herreshoff furnaces roast the concen-trate to a calcine of average composition (first 10 months of 1938) : Zn, 67.69 per cent; Pb, 0.06; insoluble, 1.75; Si02, 1.26; Fe, 7.24; CaO, 0.47; MgO, 0.36; S, 1.88; Cd, 0.1; Cu, 0.07; Mn, 0.27. The sulphur dioxide gas, after passing through a waste-heat boiler, proceeds through a recently redesigned low-resistance gas-purification assembly to the contact sul-phuric acid plant, of which the capacity is 200 tons of concentrates per day. The calcine is mixed with a portion of returned furnace residues and sintered on 42-in. by 44-ft. Dwight-Lloyd sintering machines, gas-fired. Wind-box gases pass through air coolers before filtering in a 1440-bag Dracco unit, and thence to stack. The Dracco fume is mixed with Cottrell dust, from roaster gas cleaning, and sent to the leach plant, where it is roasted (SO2 to acid plant) and leached with sulphuric acid to recover, as end products, lead sulphate, zinc sulphate and cadmium.

Jan 1, 1939

By K. C. Dean

During the investigation of the occurrence of manganese deposits in western United States, the Bureau of Mines collected 2-ton samples from three oxide manganese ores in the Columbia and Elberta Mining Districts, Tooelo and Juab Counties, Utah. To determine the amenability of these ores to standard ore-dressing methods: of concentration, extensive laboratory tests were made. The Wildcat property, one of those sampled, is 7 miles east of Fairfield, Tooele County, Utah. The ore is described as a replacement deposit and occurs along fracture and bedding planes of shale and limestone. Experimental work was done on a sample taken from a stockpile at the mouth of the shaft. The Wildcat manganese ore is intermediate in grade (25.7 percent manganese) and contains clay as the principal gangue constituent. A high-grade product was obtained with high recovery of Manganese by simple washing.

Jan 1, 1949

By M. W. Bartley, Hugh M. Roberts

Substantial deposits of Bessemer hematite have been found recently by drilling beneath Steep Rock Lake, Ontario, which is situated in the northern part of the Lake Superior Region. It will be practicable to divert the waters flowing into this lake and develop open pits on the upper pert of two large ore bodies by damming off and pumping out the water in the part of the lake in which they occur. Ultimately, the bulk of the ore will be mined by underground methods. Owing to the generally massive nature of the rocks in the area, no underground flows of major consequence are anticipated after diversion of the lake. The Steep Rock deposits are attributed in origin to hydrothermal replacement. They were formed, for the most part, along an unconform-able, brecciated contact between the Steep Rock limestone and an overlying younger volcanic series, The replacing solutions came in as igneous after-effects, following upon the intrusion of basic igneous rocks that invaded the hanging-wall volcanics. It is believed that this took place in a geological period roughly equivalent to late Middle Huronian, which was the period when the most extensive iron-bearing rocks of the Lake Superior Region were formed. Comparison is made with other deep-seated iron-ore bodies in the Lake Superior Region, the origins of which are ascribed in the discussion to hydrothermal replacement. Introduction Under the waters of Steep Rock Lake, Ontario, situated on the Canadian National Railway, 142 miles west of Port Arthur, the presence of three ore zones containing red and brown Bessemer hematite has been established. These were discovered and have been partly explored by means of diamond and churn drilling, The positions of the ore zones, designated as A, B and C, are shown on the accompanying maps and cross sections. This exploratory work, begun in 1938 by Joseph Errington* and Julian G. Cross, has been carried on by Steep Rock Iron Mines Ltd., and was continued during the winter of 1941-1942. For more than 60 years explorers have known that large quantities of hard hema. tite float of good grade existed along the south shore of Steep Rock Lake, and the presence of ore beneath the lake was inferred by many early geologists and explorers. Despite numerous previous attempts to find ore in place, actual discovery awaited the recent period of intensive exploratory effort in Canada. The results obtained in the drill holes put down since 1938 by steep Rock Iron Mines Ltd. are not only of interest, in themselves, to those concerned with the development of ore deposits, but, taken in connection with the surface exposures of adjoining formations, they form the assemblage of facts from which the geological reasoning in this paper proceeds; accordingly, they are set out here as briefly and exactly as may be.

Jan 1, 1949

By M. W. Bartley, Hugh M. Roberts

Substantial deposits of Bessemer hematite have been found recently by drilling beneath Steep Rock Lake, Ontario, which is situated in the northern part of the Lake Superior Region. It will be practicable to divert the waters flowing into this lake and develop open pits on the upper pert of two large ore bodies by damming off and pumping out the water in the part of the lake in which they occur. Ultimately, the bulk of the ore will be mined by underground methods. Owing to the generally massive nature of the rocks in the area, no underground flows of major consequence are anticipated after diversion of the lake. The Steep Rock deposits are attributed in origin to hydrothermal replacement. They were formed, for the most part, along an unconform-able, brecciated contact between the Steep Rock limestone and an overlying younger volcanic series, The replacing solutions came in as igneous after-effects, following upon the intrusion of basic igneous rocks that invaded the hanging-wall volcanics. It is believed that this took place in a geological period roughly equivalent to late Middle Huronian, which was the period when the most extensive iron-bearing rocks of the Lake Superior Region were formed. Comparison is made with other deep-seated iron-ore bodies in the Lake Superior Region, the origins of which are ascribed in the discussion to hydrothermal replacement. Introduction Under the waters of Steep Rock Lake, Ontario, situated on the Canadian National Railway, 142 miles west of Port Arthur, the presence of three ore zones containing red and brown Bessemer hematite has been established. These were discovered and have been partly explored by means of diamond and churn drilling, The positions of the ore zones, designated as A, B and C, are shown on the accompanying maps and cross sections. This exploratory work, begun in 1938 by Joseph Errington* and Julian G. Cross, has been carried on by Steep Rock Iron Mines Ltd., and was continued during the winter of 1941-1942. For more than 60 years explorers have known that large quantities of hard hema. tite float of good grade existed along the south shore of Steep Rock Lake, and the presence of ore beneath the lake was inferred by many early geologists and explorers. Despite numerous previous attempts to find ore in place, actual discovery awaited the recent period of intensive exploratory effort in Canada. The results obtained in the drill holes put down since 1938 by steep Rock Iron Mines Ltd. are not only of interest, in themselves, to those concerned with the development of ore deposits, but, taken in connection with the surface exposures of adjoining formations, they form the assemblage of facts from which the geological reasoning in this paper proceeds; accordingly, they are set out here as briefly and exactly as may be.

Jan 1, 1949

In the screening process, used to prepare particles for many applications, shape is known to have a significant effect. The degree of flakiness of construction aggregates has been considered particularly important. The objective of this research was to find values of operating parameters that optimize the separation of flaky from non-flaky particles by slotted screens. Thus an investigation was conducted to experimentally determine the influence of the particle size and thickness on the screening process. The Response surface method was employed for modelling and analysis of the data. Experiments employing a central composite design were performed on a pilot-scale, rectangular-aperture, vibrating screen to examine the effects of the screening variables the mass recovery of flaky and non-flaky particles to the oversize product. The SAS statistics package was used to fit a second-order model to each response and to analyze the fitted surface to determine the optimum levels. The optimization associated with a dual response system was then considered. The results of this study should provide a basis for optimizing screening conditions to obtain maximum recovery of non-flaky particles to the screen oversize while minimizing the recovery of flaky particles, which should be of interest to the aggregate industries.

Jan 1, 1999