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"Option pricing is used in finance for valuing options to buy (or sell) shares at some future date because it provides a convenient framework for quantifying values subject to uncertainty. As one of the main sources of uncertainty in mining is the price (sales) of the metal, this approach can also be used for valuing mining projects.The first part of this paper reviews options and option pricing; the second part presents the approach developed by Brennan and Schwartz (1985) for using option pricing to value natural resources. Several applications of this methodology have been published; these are described. From a mining point of view, the assumptions made by Brennan and Schwartz are too simplistic. The weaknesses are discussed with a view to improving an apparently promising new way of assessing the value of projects. IntroductionThe collapse of the British merchant banking group, Barings, has highlighted the risks that can be incurred by speculators and arbitragers in the futures and options markets. But this negative attention on futures and options should not make us forget their positive aspects. They can provide producers and consumers of metals with more predictable sales prices. The introduction of the new traded average price options, TAPOS, by the London Metal Exchange in January 1997 is a response to this need. Equally important, the theory that the finance industry has developed for valuing options provides an interesting framework for valuing mineral projects as well. While this paper was being revised, the South African gold mining house, JCI, announced that it was using a methodology based on option pricing for valuing the mineral rights to deeplevel gold resources (see Box 1)."

Jan 1, 1997

By X. Cao, H. Huang, Z. Dai

"Crystal phase of copper-containing slag regulation by the slag viscosity, cooling speed and cooling method, where the slag viscosity is related to the temperature and alkalinity. According to the mineralogy properties of a copper-containing slag, experiments of crystal phase regulation and flotation were conducted. When the copper-containing slag that adding a small amount of calcium oxide was cooled slowly at a rate of 3°C/min and about 1050°C n a cinder inclusion system, the viscosity of slag can be remained under 0.25 Pa·S and more than ??% of copper particles that the grain size is larger than 20 ?m in slag. The whole flow of flotation experiment was carried out to recover copper from the copper-containing slag with crystal phase regulating and the copper concentrate grade was ?????%, the recovery efficiency of copper was 94.18%.INTRODUCTIONChina's annual output of copper slag is more than 6 million tons, the current total has reached 80 million tons. It is equivalent to 640 thousand tons of copper metal with the copper grade of 0.82%. Most of the smelting slag were storage. It is not only occupy the land and pollute the environment, but also make a huge waste of resource (Alp, Deveci, & Süngün, 2008; Carranza, Iglesias, Mazuelos, Romero, & Forcat, 2009; Gorai, & Jana, 2003), therefore, it is good way to achieve copper slag resources by the effective recovery of valuable component from copper smelting slag, which is an important measure of the current process of copper smelting slag and implement the central authorities to vigorously develop the circular economy, improve the recycling of resources, increase copper production of intensive development (Zhou, et al., 1994; Zhang, Zhang, & Wang, 2005). Currently, researches on comprehensive utilization of the coppercontaining slag made a much progress (Wei, 2004; Liu, Gai, Yang, Sui, Li, & Fu, 2008; Liu & Zhu, 2008; Zhang, 2010; Sun, Chen, & Tang, 2012; Qin, Wang, Ren, Wei, Peng, & Gu, 2012). Flotation is one of the most effective method to recover the copper from smelting slag, which has the features of low cost and high efficiency (Song & Liu, 2001; Zhang, Wang, & Li, 2012). But the copper particles in the copper smelting slag distribution is very uneven, and the thickness of the material is very serious. The copper content in the micro level is higher, the size of copper sulfide ore is less than 0.043 mm, which leads to the difficulty of the monomer dissociation (Tossavainen, Engstrom, Yang, Menad, Lidstrom, Larsson, & Bjorkman, 2007; Moustakas, Mavropoulos, Katsou, Haralambous, & Loizidou, 2012). In this study, according the process mineralogy of a smelting copper slag, the crystal of smelting copper slag was optimized by controlling the temperature, alkalinity, cooling rate and cooling method, which makes the fine copper mineral particles in the copper slag crystal further, and can be used to meet the particle size requirements of flotation, thereby enhancing the flotation of copper."

Jan 1, 2016

By Xiaolong Bi, Shaohua Luo, Longjiao Chang, Shiyuan Cao, Jianan Liu

The abstract discusses the extraction of silica from nickel laterite ore using a hydrothermal process with sodium hydroxide. The effects of reaction temperature, time, and NaOH-to-ore ratio on silica extraction were investigated. The optimal conditions were determined, achieving over 98% silica extraction. The mechanism involves the reaction of Si in lizardite and quartz with sodium hydroxide, forming sodium silicate solution. Other metals like Mg, Fe, and Ni are enriched in the residue.

Apr 21, 2022

By Oliver Bowles

Cementing materials of mineral origin were well known to the ancients. Ordinary lime and gypsum plasters were the first to be recorded by historians. The next development was the discovery that certain limes would set under water, but the hydraulic property was not definitely attributed to the presence of clay in the limestone until many centuries later. The Romans advanced a step nearer to modern cement in the development of 'pozzuolana', a mixture of volcanic ash or trass with hydrated lime. The silicate of aluminium in the volcanic rock combined readily with the lime, forming a hydraulic mortar or cement which was widely used. Natural Cement In Europe (1) No further progress was made in the art of manufacturing cement for several centuries, during which the Roman Empire declined and passed away, and the Anglo-Saxon race slowly and painfully evolved through the Middle Ages an ever-increasing prestige. An Englishman, John Smeaton, is credited with the honour of the next important development, for he employed a little-known cementing material-natural cement-in constructing the Eddystone lighthouse in 1756. It was called 'natural' cement because it was made from a natural rock with no additions of other materials. The process consisted of calcining an argillaceous limestone at a comparatively low temperature and grinding the product to a fine powder. Care was exercised to keep the temperature low, and any material burned to the clinkering point was thrown away, although such material was, as learned at a later time, Portland cement.

Jan 1, 1933

By C. Samson, R. S. Smith, S. W. Hefford

"Abstract - Time-domain electromagnetic systems are most sensitive to highly conductive targets during the transmitter on-time. Data collected during the on-time is highly influenced by the geometric relationship between the transmitter and the receiver. Unless corrections can be applied for these geometric variations, the ability to correctly detect and identify highly conductive targets can not be fully realized. Variables affecting the relative position between the transmitter and receiver include changes in the position of the receiver with respect to the transmitter, variations in transmitter attitude, and transmitter loop deformation. The level of accuracy in the determination of the relative geometry required to permit complete removal of the effects due to geometric variations is different for each of the variables and is dependent on the depth of the target. The most influential geometric variation involves changes in the relative position of the receiver with respect to the transmitter along the direction of flight; this variable, therefore, requires the highest degree of accuracy. The accuracy required for receiver motions along the vertical direction is roughly one order of magnitude less, and in the lateral direction, several orders of magnitude less. The objective of this paper is to relate the sensitivity of the response to transmitter-receiver geometry to the ability of an airborne, time-domain electromagnetic system to resolve a highly conductive vertical target. This is achieved by a detailed analysis of the effect of the individual x, y, and z distances between the transmitter and the receiver, the transmitter attitude (roll, pitch, and yaw), and transmitter deformation.Sommaire - Les systèmes électromagnétiques en domaine temporel sont particulièrement sensibles aux cibles à forte conductivité durant le temps d’excitation. Les données collectées durant l’émission du transmetteur sont fortement affectées par les relations géométriques entre le transmetteur et le récepteur. Si un facteur de correction n’est pas introduit pour tenir compte de ces variations géométriques, la capacité de ces systèmes à détecter et identifier correctement les cibles fortement conductrices ne peut pas être pleinement réalisée. Les facteurs affectant les positions relatives du transmetteur et du récepteur comprennent les changements de position du récepteur relativement au transmetteur, les changements d’altitude du transmetteur et la déformation de la boucle du transmetteur. Le degré de précision requis pour déterminer la configuration nécesaire pour compenser complètement l‘effet des changements géométriques est différent pour chacune des variables et dépend de la profondeur de la cible. Les changements géométriques qui ont le plus d’influence sont ceux qui font varier la position du récepteur relativement au transmetteur dans l’axe de la ligne de vol; c’est donc cette variable qu’il faut contrôler avec le plus de précision. La précision requise pour le suivi des mouvements du récepteur le long de l’axe vertical est moindre d’environ un ordre de grandeur, tandis que selon l’axe latéral elle est diminuée de plusieurs ordres de grandeur. Le but du présent article est d’établir comment la susceptibilité de la réponse à la géométrie transmetteur-récepteur affecte la capacité d’un système électromagnétique en domaine temporel aéroporté à reconnaître une cible verticale fortement conductrice. Cet objectif est atteint par l’analyse détaillée de l’effet individuel des distances x, y, et z entre le transmetteur et le récepteur, l’attitude du transmetteur (lacet, roulis, tangage) et la déformation du transmetteur."

Jan 1, 2006

By Rose Vera, Alejandro Luna

El programa “Fortaleciendo capacidades para la empleabilidad local” es una iniciativa que busca incrementar las oportunidades de empleo formal y digno para los moqueguanos. Con un enfoque innovador e integral, y siguiendo los principios del Plan de Minería Sostenible, permite gestionar la oferta de trabajo de Moquegua para conectarla con la demanda laboral de la región y del país, mejorando previamente sus capacidades y competencias. A través de capacitaciones en los sectores y ocupaciones con mayor demanda en el mercado, se incrementan las oportunidades de trabajo para la población local, más allá de la minería.

Sep 29, 2023

I am honoured and very pleased to have been given the opportunity this evening to say a few words of thanks not only on behalf of all the guests but especially for the delegates and accompanying persons attending the 13th Congress of the Council of Mining and Metallurgical Institutions. Firstly, I would like to congratulate Sir Hamilton Whyte,KCMG for his most interesting address. In his far ranging talk, when he showed knowledge of widely diverse subjects, I had a brief fear that he was going to be talking about the details of support methods in deep level mines, or how to avoid flotation problems in multi-metal mines. Although he did not go that far, he touched on subjects which have arisen this week - long term planning and secure supply of minerals at acceptable prices. The dire predictions of the Club of Rome have been debunked with a far more elastic supply of minerals having been proved. Combined with the importance of a falling birthrate in some parts of the world, this will lead to many changes in the future, when hopefully governments will take the long term view rather than look at the next budget or the next election. Maybe some of them are not too lazy to do this for all of us. However as a fellow Ukranian, I feel that he might have been called something different if he had been in Australia. Sir Hamilton, thank you for your talk. Once upon a time - and this is not a fairy story - there was a cobbler who had two sons; one very bright who became a professor of mathematics; the other, dim, who became a millionaire shoemaker. Asked for the secret of his success, the millionaire attributed it to a vital piece of economics which his father had imparted, "Be content with small margins on a large turnover." "So", said the millionaire, "I make my shoes for $2 a pair and sell them for $5. I am very happy with the three per cent profit."

Jan 1, 1986

By J. E. Danoczi

ABSTRACT A diamond processing plant is being designed for the Star–Orion South diamond project in central Saskatchewan. Key to the plant is diamond liberation, which occurs in the comminution section and is the process of breaking up kimberlite rock as gently as possible to minimize diamond damage, particularly in larger, high-value diamonds. Kimberlite from the crater area of a volcanic pipe is generally softer than kimberlite from the diatreme zone. Softer kimberlite, comprising the majority of Star– Orion South deposits, can be readily broken up using abrasion and attrition by autogenous grinding mills, the preferred comminution method for minimizing diamond damage.

Jan 1, 2013

By D. R. Tesarik

The factor of safety, the traditional measure of stability for earth embankments, is graphically presented in factor of safety charts in this Bureau of Mines report. Factor of safety contours are drawn for homogeneous earth embankments for two contrasting situations: (1) no phreatic surface and (2) a phreatic surface that assumes 10-pct freeboard. The factor of safety can be read directly from the charts if the physical properties of the soil and the geometry of the embankment are known. The curves provide a quick first approximation of the "most stable" and "least stable" condition of the embankment. The Simplified Bishop Method was used for the safety factor calculations, and a sequence of least squares curve fitting steps was used to present the factor of safety in final chart form.

Jan 1, 1981

By Mohamed Mekkawy, William W. Wheaton, Ira Brotman

"The Virginia Port Authority and the U.S. Army Corps of Engineers are partnering to construct the Craney Island Eastward Expansion (CIEE) to meet the dual purpose of extending the life of Craney Island as a dredged material management area and providing land for a state-of-the-art marine terminal. The over 500-acre (200-hectare) expansion provides additional upland dredged material capacity for the Hampton Roads Harbor by constructing perimeter dikes, that once filled, will provide land for the development of a container terminal. In the winter of 2010/2011 the first stage of sand fill was placed, followed by the installation of approximately 12 million linear feet (MLF) (3.6 million linear meters, MLM) of marine PVDs. With over 36 MLF (10.9 MLM) of PVD required to complete dike construction the project will be one of the largest PVD installation project in the U.S.This paper details the challenges associated with the construction of the cross dikes, in particular the design, testing, installation and monitoring of prefabricated vertical drains (PVDs) installed overwater to depths of over 130 feet (40 meters) for foundation improvement in the insitu very soft Norfolk Clay. With expected settlements of 20–30 ft (7-10 m) and 30 percent average strains, the discharge capacity of the PVDs was of particular concern. Laboratory data is presented showing the magnitudes and variability of discharge capacity under different confining pressures in both a straight and buckled condition.The method of installation and monitoring of the marine PVDs in open water included developing a specialized barge and sophisticated positioning and data collection system to verify installation location, depth of penetration and track quantities. An observational method, including material testing, detailed surveys, periodic in-situ testing, and instrumentation, was utilized by the project team to assess the project’s progress and allow for validation of consolidation and strength gain rates and magnitudes."

Jan 1, 2017

By L. S. Montagna, R. M. C. Santana

"Since the industrial revolution, plastic products sector has growing bigly, however this fact presents as consequence the increase of municipal plastic waste (MPW).The aim of this work is to developmet polymer mixture from MPW with the adittion of rubber tire (TR) post use and to study the mechanical and morphologycal properties. The polymer mixtures Polypropylene/High impact polystyrene/TR (PP/HIPS/TR), where rate weight TR used was 10, 20 and 30 % and with three size particles (500, 710 e 1000 µm). The specimen tests were obtained by injection molding. Preliminary results of mechanical properties showed that the increase of TR influence in a reduction of the flexural and tensile resistance. Results by scanning electronic microscopy on the fracture surface of mixtures PP/HIPS/TR showed a better interaction of TR particle with HIPS than with PP. Also, the presence of microcavoids was observed, characteristic in PP/HIPS blends, favouring in the increase of its opacity.IntroductionOne great part of the municipal solid waste (MSW) is composed of polymer mixed since commodity plastics, blend to polymer composite. The processing of plastics mixtures for recycling has been attempted with some success, but poor mechanical properties and uncertain economic value limit their more versatile reuse. Polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), poly(vinyl chloride) (PVC) and polystyrene (PS) are among the most common plastic waste, predominantly used in packaging food industry [1].One other problem that preoccupy to the society is the increase of rubber tire waste in the proportion of MSW. In Brazil, from 1999 to 2004, 39 % from 386 mil ton of tire post-use were destined to ciment Industry as source of energy [2]. However this destiny produces one other problem, environment pollution, due to gas mixture emitted.Recycling represents a valid alternative to the disposal of post-consumer plastics in common landfills if it is possible to obtain new materials with good final properties compatible with practical and, above all, by cheap methods [3]The reutilization of group tire rubber (TR) powder as a dispersed elastomeric phase in a thermoplastic matrix offers an opportunity to design second generation materials which would be recyclable due to the thermoplastic matrix and which potentially could present thermoplastic elastomer (TPE)-like mechanical behavior. [4]."

Jan 1, 2008

By C. Dupuis

Thiourea is a promising reagent for gold extraction especially from refractory ores that cannot be treated by traditional cyanidation route. In this study recovery of gold from thiourea leaching solutions was investigated by direct electrowinning. The electrolysis cell consisted of a carbon flow-through cathode and a lead anode. The anodic and cathodic compartments were separated by a membrane. Galvanostatic mode was chosen for operation of the cell. Factors affecting recovery efficiency such as cathode thickness, linear flowrate, current intensity, thiourea and gold concentrations were investigated. The influence of some species in solution on efficiency and selectivity of recovery was investigated. Gold recovery reached 99% but current efficiency was lower than 10%. The complex formed with ferric ion and formamidine disulfide are reduced before gold-thiourea complex. Thiourea consumption occurred during leaching mainly by oxidation and reaction with dissolved copper.

Jan 1, 1989

W. M. Courtis, Detroit, Mich.: Except for free-gold ores, I have always believed in scorification. I think the crucibleassay gives silver low. We found this out at the Wyandotte works in assaying Silver Islet ore. The mine-managers made us, and also the check-assayera, run one of the duplicates by

Jan 1, 1896

By H. J. R. Way

Dr H. J. R. Way: In his reply to my queries Mr Bath still adheres to his statement that it may be possible to replace the estimated R200 million reduction in gold revenue in 1980 by exports of ferro-chromium, and apparently based his conclusion on a growth rate in demand for corrosion resistant steels of 10 per cent per annum in the next few years. As I pointed out at the previous discussion at Middelburg this would entail a production of about one million tons of ferro-chromium in 1980. Exact statistics of South African ferro-chromium production are not available, a fact which is very much to be regretted. But statistics of exports of ferro-chromium are available from "Foreign Trade Statistics" of the Customs and Excise. These show that South Africa exported 99,580 short tons in 1967. The quantity of ferro-chromium consumed in South Africa in 1967 was fairly small and we can therefore assume that the production was 99,580 tons. For this amount to grow to 1,000,000 tons in 1980 would require a growth rate of 19.4 per cent per annum. At 10 per cent this would grow to 344,000 tons and at 7 per cent 240,000 tons. The following growth rates in the form of average trends are pertinent: STEEL - Per annum World steel ingot production - 1957-67 – 6.8 per cent Free-world ingot production - 1957-67 – 6.0 per cent Consumptions of crude steel by four major Free-world Consumers - 1957-67 - 5.6 per cent CHROMITE World production - 1952-67 - 2.5 per cent South African total sales - 1948-67 – 5.4 per cent South African exports - 1948-67 – 3.9 per cent United States consumption, very irregular, but - 1962-67 – 6.5 per cent FERRO-CHROMIUM - Per annum United States consumption - 1952-67 - 6.5 per cent South African exports - 1957-62 - 25.2 per cent South African exports - 1962-66 - 41.9 per cent South African exports - 1966-68 - 21.2 per cent These figures show that exports of ferro-chromium have been growing at a very high rate varying from 21.2 per cent to 41.9 per cent since 1957, but in view of the market situation it seems somewhat doubtful if that high rate can be maintained up to 1980. Of our 1966 exports U.S.A. took 63 per cent which was 53 per cent of their total imports. Their average consumption is trending at a growth rate of 6.5 per cent per annum from 1952-67, but the growth from 1964-66 was 5- 2 per cent and 1966-67, -12 per cent!

Mar 1, 1968

By Howard N. Eavenson

TWO months ago, just after the coal code hearing in Washington, one of our leading liberal weeklies printed a study of the coal industry made by an economist in the Administration, and on the outside cover bad it featured as "Coal-A Dying Industry." There are, of course, different opinions as to the accuracy of this characterization and I want to present some of the facts about the outlook for the bituminous industry for a short time ahead. In view of what has happened in the industry within the recent past it would be futile to attempt to make any prophecy about what is likely to occur in the future. We all know that a prophet is not without honor save in his own country, but it is likely that anyone undertaking this role about this industry would soon find himself in no man's land. One can, with some slight degree of safety perhaps, outline present conditions and tendencies and draw some inferences as to what the future may hold.

Jan 1, 1933

By J Coombes, R Sterk

The efficiency of the Australian and New Zealand stock exchanges relies on a fully informed market: shareholders and investors are fully and transparently informed of all material information relating to the shares. These principles of transparency and materiality are similarly core to the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves (the JORC Code). The JORC (Joint Ore Reserves Committee) Code also includes a principle of competency to ensure that the person providing the material information for public disclosure is suitably qualified and experienced.Since its inclusion into the ASX (Australian Securities Exchange) Listing rules in 1989, the JORC Code has continually improved and evolved in attempts to meet the market’s need for competent, transparent and informed disclosure. The quality and effectiveness of Public Reporting in accordance with the JORC Code is under constant challenge: some practitioners argue there is insufficient regulation, while others argue the need for greater self-regulation.This paper contributes to that discourse by exploring how well the Reporting expectations are met, and, whether Public Reporting in accordance with the JORC Code has a material impact on share-price movement.CITATION:Sterk, R and Coombes, J, 2017. Public reporting – new standards or no standards?, in Proceedings Tenth International Mining Geology Conference 2017, pp 423–432 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By Jorge Gibson, P. Chris Pistorius, Megha Jampani

Increased utilization of natural gas in blast furnace ironmaking can decrease both the cost and the carbon intensity of ironmaking, given current US natural gas prices. In this paper, three ways to utilize natural gas are compared: tuyère injection, prereduction of iron ore, and shaft injection. The basis for comparison includes coke replacement ratios, carbon intensity and furnace productivity. These were calculated using relevant mass and energy balances, a blast furnace productivity correlation based on the bosh gas flow rate, and measured and modeled prereduction kinetics. Of the natural gas utilization methods, prereduction has the highest effective coke replacement ratio (and hence the largest advantage in raw material cost), but is likely to have the highest capital requirement.

Mar 1, 2017

By Christiana Mystrioti

Greece is the only EU country with extensive nickel laterite deposits. Since the 1960s, the Greek laterites are treated for ferronickel production via a pyrometallurgical route, which involves pre-reduction of the ore in rotary kilns and reduction smelting in electric arc furnaces. Due to the rising cost of energy and the decreasing grade of mined laterites, the pyrometallurgical treatment is economically marginal. For this reason, alternative treatment processes are currently under investigation. Potential applicability of hydrometallurgical treatment, using either H2SO4 or HCl, under atmospheric pressure conditions, for Ni and Co extraction from two low grade laterite ores, was examined in the present work. The two samples were selected to represent the different mineralogical composition of the saprolitic and limonitic ore deposits of the Greek laterites. The investigated parameters were temperature (65–90 °C), acid concentration (1–4 N) and solid to liquid ratio (10–30% w/v). The results indicated that HCl was more efficient than H2SO4 for the treatment of the saprolitic ore; Ni and Co extractions were very high for both elements, up to 98% and 96% respectively, while H2SO4 could leach efficiently Ni, up to 100%, but extracted only 34% of Co. Hydrochloric acid was also more efficient for the treatment of the limonitic ore, with Ni and Co extractions up to 98.3% and 87.6% respectively. With H2SO4 the maximum extractions were 71.3% for Ni and 52.1% for Co.

By Ira Brotman

The Virginia Port Authority and the U.S. Army Corps of Engineers are partnering to construct the Craney Island Eastward Expansion (CIEE) to meet the dual purpose of extending the life of Craney Island as a dredged material management area and providing land for a state-of-the-art marine terminal. The over 500-acre (200-hectare) expansion provides additional upland dredged material capacity for the Hampton Roads Harbor by constructing perimeter dikes, that once filled, will provide land for the development of a container terminal. In the winter of 2010/2011 the first stage of sand fill was placed, followed by the installation of approximately 12 million linear feet (MLF) (3.6 million linear meters, MLM) of marine PVDs. With over 36 MLF (10.9 MLM) of PVD required to complete dike construction the project will be one of the largest PVD installation project in the U.S. his paper details the challenges associated with the construction of the cross dikes, in particular the design, testing, installation and monitoring of prefabricated vertical drains (PVDs) installed overwater to depths of over 130 feet (40 meters) for foundation improvement in the insitu very soft Norfolk Clay. With expected settlements of 20?30 ft (7-10 m) and 30 percent average strains, the discharge capacity of the PVDs was of particular concern. Laboratory data is presented showing the magnitudes and variability of discharge capacity under different confining pressures in both a straight and buckled condition. The method of installation and monitoring of the marine PVDs in open water included developing a specialized barge and sophisticated positioning and data collection system to verify installation location, depth of penetration and track quantities. An observational method, including material testing, detailed surveys, periodic in-situ testing, and instrumentation, was utilized by the project team to assess the project?s progress and allow for validation of consolidation and strength gain rates and magnitudes.

By Richard E. Hucko

The Coal Preparation Division of the Pittsburgh Mining Technology Center conducted an investigation to assess and compare the pyritic sulfur reduction potential of coal-pyrite flotation and high-gradient magnetic separation (HGMS). Tests were run on three coals--an Upper Freeport bed coal, a Lower Kittanning bed coal, and a Pittsburgh bed coal--to establish grade- recovery relationships characteristic of both processes. Representative portions of each coal sample were crushed to two top sizes--nominal minus 35 mesh (0.5 mm) and nominal minus 100 mesh (0.149 mm)--and subjected to conventional froth flotation. The froth product was then beneficiated by coal-pyrite flotation or HCMS to provide a direct technical comparison of the two processes. At minus 35 mesh (0.5 mm), the size normally employed for coal flotation, both coal-pyrite flotation and HGMS effectively separated pyrite from coal, and the performance of the two processes was essentially the same. At a size of minus 100 mesh (0.149 mm) , however, the performance of HGMS exceeded that of coal- pyrite flotation. The separations effected by HGMS were more efficient at minus 100 mesh (0.149 mm) than at minus 35 mesh (0.5 mm). On the other hand, it was concluded that either the effectiveness of coal-pyrite flotation decreases with diminishing top size, or the process has not been optimized to treat material finer than 35 mesh (0.5 mm).

Jan 1, 1981