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By F. Stober, D. Wanblad, J. Ndlovu, L. R. Nelson, L. P. S. de Villiers

The single six-in-line furnace of the Polokwane Smelter is the largest installed high-intensity furnace for platinum group metals (PGM) base metals sulphide smelting in the world. The furnace employs state-of-the art technology to deliver a planned throughput of 650 000 t/a dry concentrate at a design 68 MW power input. This furnace, at double the capacity of previously existing PGM furnaces, offers low unit operating and capital cost through the resulting economies of scale. Key features of the design include:

Jan 1, 2005

By Claude Deveau

"Studies on the performance of Falcon batch type concentrators treating ultrafine tantalum at Tanco have revealed that very fine heavy minerals are concentrated within certain areas of the concentrate bed. This information led to the design of a bowl which would allow entrapped lighter low grade particles to escape while providing more space for heavier particles to be recovered in the bed.Numerous tests were then completed with a modified batch-type and non-fluidized Falcon bowl in which the diameter of the discharge lip was adjusted downward manually in steps. This allowed for the gradual building of a higher grade concentrate bed.This work ultimately led to the design of a new Falcon with an automated continuously variable lip. In April 2005, Tanco commissioned the first Falcon UF600.This paper will discuss laboratory scale results and also plant performance of the Falcon’s UF technology.INTRODUCTIONTantalum Mining Corporation of Canada, also known as Tanco, is a wholly owned subsidiary of Cabot Corporation based in Boston, Mass. Operating since 1969, the underground highly mechanized room and pillar operation produces tantalum, lithium and cesium minerals and is located a 2 hour drive east-northeast of Winnipeg Manitoba, Canada.At Tanco, tantalum is recovered using conventional gravity concentration, enhanced gravity concentration and flotation. This paper will discuss how the need for improved equipment to treat very fine tantalum particles was filled by a machine which was modified to the point of creating a completely new technology.In November 2003, Tanco began the investigation for the potential use of a high g-force smooth walled concentrator for treating ultra fine tantalum produced by its flotation circuit. Until then, the tantalum flotation concentrate had been treated by a circuit which consisted of a Mozley Multi-Gravity Separator 902 (MGS), a Mozley MGS 900 and a Bartles cross belt concentrator. Through QemScan analysis, it was found that the majority of the losses from this circuit were of an extremely fine nature which exceeded the recovery limits of equipment on hand. Mean particle size of the tantalum losses was less than 10 µm."

Jan 1, 2006

By George M. Douglas

The southeastern shores of Great Slave lake present a curious anomaly in geographical and geological exploration, in that an area so large and important, and withal so comparatively accessible, should nevertheless have remained unexplored, unmapped, and indeed almost unknown, until quite recent" times On their return from the famous journey to the mouth of the Coppermine, the band of Indians with whom he travelled led Samuel Hearne across Slave lake. He was the first white man to see that great body of water and it is rather curious that it should have been seen first from the north rather than from the south. Hearne's account of the lake is vague, and he made no attempt ?to map the part through which he travelled. About 30 years later John Franklin, on his first journey to the Arctic, crossed the lake from the mouth of the Slave river to the Yellow Knife river. Franklin's maps show all of his route in accurate detail, except that part of it which lay through Slave lake. In 1833-34, Captain, afterwards Sir George, Back made the first exploration of the eastern end of the lake. Captain Back was then on his way to the Arctic coast by way of the Great Fish river, and his Indian guides led him through Great Slave lake by the route they had followed from time immemorial. This route, partly because of its directness, and partly because of its sheltered character, lay through the great mass of islands in the middle of the lake to the Talthei narrows, and thence along the sheltered north shore with its many coves and harbours. Pere Petitot made extensive journeys in Slave lake as well as other parts of the far north.

Jan 1, 1929

By Wei Yingchun

Based on the deep burial depth of coal deposits in Huainan-Huaibei coalfields, Anhui Province, China, this paper puts forward the concept of partitioning of coal deposits according to occurrence conditions. This process is controlled by tectonic forces. The classification scheme of coal deposits exploration types is presented according to occurrence and mining conditions of coal deposits as viewed from the perspective of deep coal exploration properties. The principles underlying geological exploration services for the resources development are incorporated. There are six exploration types of coal deposits in the Huainan and Huaibei coalfields. Exploration models tailored to different types of exploration have been established and exploration strategies corresponding to different exploration models have been proposed. Steady-state temperature must be measured for the deep heat-harm type of coal deposit. The sealing coring of mine gas samples should be performed for the high mine gas type of coal deposit. For coal deposits with complex structures, such as those located beneath nappes, coal-controlling structural styles must be performed. Existing data on shallow districts are very important to the research of folds and fault-block types of coal deposits beneath and peripheral to old and existing coal mine areas. For the types of fault-block coal deposits hidden by thick Cenozoic cover, particular attention must be paid to comprehensive use of research on regional coal occurrence law and geophysical methods. The present work promotes the exploration level of coal deposits in Huainan-Huaibei coalfields to best meet the need for sustainable development of the coal industry.

Aug 1, 2013

By M. Matthias

A study, part of a doctoral dissertation (Matthias, 1991), was conducted during 1987 and 1988 to establish the means by which professionals assess and maintain their competence during the various stages of their careers. The study elicited responses from fifty-nine subjects representing engineering, pharmacy and medicine (twenty subjects from engineering, nineteen from pharmacy and twenty from medicine) on their perception and assessment of continuing competence. The findings revealed a wide variation of how professionals perceived their continuing competence and the means they adopted to keep current. The implications of the study are significant for adult education practice and theory building. The author strongly believes that now, more than ever, engineers must take ownership of their careers and professional development activities. While management and supervision have a key role to play, it is the engineer, who is ultimately responsible for the scope, planning and implementation of her/ his professional development needs. An example from one high technology company will illustrate these points.

Jan 1, 1999

By Sophia Wong

Nickel is used in a wide variety of applications from consumer goods to industrial uses. In many of these uses, nickel contributes to the environmental attributes of the product. The challenge, however, is measuring that contribution, comparing it to the environmental cost of production, and communicating the role of nickel to the customer in a way that is easy to understand. This paper presents the Nickel Institute?s approach to climate change as a global commodity industry association, and discusses where we stand with regard to some of these key questions. It also identifies issues for the nickel industry moving forward ? challenges that are likely to be common to other commodities.

May 1, 2009

By M. A. Creaney

"The Construction Group is responsible for the construction of all of Placer Dome’s major projects and contributes to the development of most major feasibility studies. This group includes an international collection of Placer Dome people who have built mines in Papua New Guinea, Australia, Chile, the United States and Canada. This paper outlines the changing role of the Construction Group from the early days of single projects to today, when several projects are in various phases from feasibility to construction. The projects’ total annual budgets have from time to time exceeded one billion dollars. IntroductionAs the competition increases globally between the major gold mining companies, the impetus continues to build mines at the lowest cost with the shortest construction schedule. Placer Dome has more than met that challenge by building mines around the world at a pace that was not contemplated 15 or 20 years ago. Since 1960, Placer Dome has built 30 mines and expansions at a cost of nearly 4.5 billion dollars.In the last six years alone, Placer Dome has built 14 mines and expansions, worth 2.6 billion dollars. The company’s success is due primarily to Experience, Innovation, People and Standards.The diversity between projects, let alone the pace, has been a challenge. Placer Dome has built mines around the world in a variety of extreme climates and distinctive cultures. The construction experience gained from these projects has allowed Placer Dome to develop an extensive knowledge and data base making it easier to “fast track” projects.Through the years Placer Dome has developed a human resource base. It now has an experienced and adaptable core team of people able to set up construction projects and build mines anywhere in the world. By developing standards and systems to support the projects they can act as soon as a new project is approved, and complete the projects quickly and effectively. The result is that Placer Dome now has the construction expertise to build its own mines, giving them the competitive advantage that allows them to design and construct a mine in the least time at the lowest capital cost. This was demonstrated in March 1997 with the completion of the construction of two new mines in 12 months."

Jan 1, 1998

By Michael Cullen

The Quinsam Coal Mine is in the process of extracting a panel beneath the mine access road. To prevent damage to the road, and adjacent powerline, it was necessary to establish a ?protection zone? within which the extent of mining would be limited. The protection zone is analogous to the setback limit. For economic reasons it was desirable to make the protective zone as small as possible, and with the greatest extraction ratio possible. The size of the protective zone was established by determining the angle of critical deformation using the numerical model FLAC, coupled with field data on subsidence from the Mine. The angle of critical deformation (defined as the angle, measured from the vertical, at which intolerable damage is sustained by a structure) was determined to be between 0 and 5 degrees. The allowable extraction ratio in the protection zone was established using the ARMPS method of pillar design coupled with field data on pillar stability from the Mine. Excavations spans to prevent caving were determined by historical experience and field data on span stability from the Mine, coupled with numerical modeling. The minimum pillar size was determined to be 7.5m. The maximum pillar height was established at 2.5m. The maximum allowable excavation span was determined to be 8.5m. With these criteria, extraction ratios between 54 and 73% (measured in plan view) were determined to be appropriate for the protection zone.

May 1, 2001

By Walter F. Atkins

Fair market value, in the legal sense , is the price which a prudent and knowledgeable buyer and a prudent and knowledgeable seller, acting without constraint or compulsion , will agree upon to exchange an asset. In the ordinary commercial or engineering usage, the term may imply simply the market value or a reasonable and equitable price. The engineer evaluator who is called upon to express an opinion about the fair market value of an asset may be able to base his estimate on the sale price of similar assets or on the market values of stock. Frequently such indicators of value are not available and the evaluator must devise other means of appraisal. Mineral resource properties may be thought of as having value by virtue of the existing or potential ability to produce at a profit. Conventional procedures permit the computation of the present value of future revenues having due regard for the time value of money and the risks attendant upon the realization of the venture. Such computations have gained wide acceptance as a basis for the estimation of fair market value.

Jan 1, 1977

By Jürgen Kretschmann

The Islamic Republic of Iran is a very important producer of raw materials in the world. The country holds 68 types of minerals, including salt, sand and gravel, chrome, lead, zinc, copper, coal, gold, and iron-ore. With more than 37 billion tons of measured and indicated reserves and 55 billion tons of total mineral resources, Iran is ranked among the 15 major mineral-rich countries. Sangan iron-ore mines (SIOM) is one of the biggest iron ore mining complexes in Iran, located in a remote, but strategically important area near the Afghanistan border. The Iranian government has planned several mining projects in this region for a stepwise development over the next 5 years to satisfy the growing demand of the Iranian steel industry. In cooperation with private companies, these projects shall be realized as sustainable as possible. This paper introduces SIOM and describes socially responsible activities undertaken during the initial development of this mining complex. The effects of these activities will be demonstrated. Unique attributes of the Sangan area have a significant impact on the acceptance of SIOM by regional stakeholders. The government has made several social investments that benefit workers´ families and the community. They are attempts to build social capital for the mining operations and demonstrate a commitment for socially responsible mining to the communities and the local population. They aim to create a balance between the local and regional expectations and requirements and the necessity to secure the corporate profitability at a reasonable and sustainable level. Investment in socially responsible activities is not a choice but a necessity to improve the relations between mining companies and stakeholders in the communities. It is recommended that social investments should be carefully planned and implemented from the early stages of mining activities, and should proceed throughout the life cycle of the mines.

Aug 1, 2013

By G. G. Bowser

PERUSAL of a list of present-day commercial explosives perhaps does not convey a full realization that there has been a great deal of improvement since the original dynamite was discovered nor that, in recent years, great developments have taken place in specialized explosives. This is true particularly of high-explosives for use in metalliferous mining or what is more commonly termed 'hard-rock' mining. Not many decades ago, only two or three types of explosive were avail-'able for commercial use. One was black blasting powder. Another was ordinary nitro-glycerin dynamite in various strengths. Black blasting powder remains with but very little change. Despite its ancient lineage, it is still with us as perhaps the sole explosive in use today which is almost identical in appearance, physical properties, and working ability or execution co the original. Which dynamite the story is different. Its evolution may be likened to that of the dog, nitro-glycerin as first discovered being the counterpart of the wild dog and, like it, dangerous and hard to control. The original dynamite as made by Nobel might then be considered as representing the first domesticaced species. This original dynamite, however, has been 'crossed with other bloods' until one sees now many distinct 'breeds' in the list. Present-day explosives still have the 'bark' and the 'bite', but with control and research have come many improvements; and types have been created which are specially adapted for particular kinds of work. We still have the direct descendant of Nobel's dynamite in the form of an improved nitro-glycerin dynamite. This C-I-L explosive, Polar Dynamite, is no longer the best type to use in the hunt for gold, silver, iron, and other metals. There have been developed other explosives more suitable for chat work. In Canada, such explosives are accomplishing this work effectively, not only where climatic conditions are moderate but through the rigours of our northern winters, with their sub-zero temperatures.

Jan 1, 1938

By S. Beitler

The availability of renewable energy does not meet the demands of consumption. Hence, fossil fuels will continue to be an important energy source, and coal promises to cover the requirements for the coming decades. Because of its high energy content, deep lying bituminous coal and anthracite are important for energy generation. One trend in the future of coal mining is thin seam mining, because thick seams more and more have been exploited. A well-known and approved longwall mining method for thin seams is plowing which has big advantages compared to a shearer because of its compact design. The extraction of those thinner coal seams will become more and more important in coal industry and therefore the plow will receive more attention in future. Most approaches in longwall automation are focused on the shearer and need a more or less intelligent exploitation machine. Therefore those approaches cannot be used for the plow technology. The authors introduce a shield-data-based horizon control (SDHC). The developed approach integrates the shield data provided by the roof support and process monitoring into the horizon control process to keep the plow in seam even if the seam trend changes. This control concept can be used for the shearer as well as for the plow. The basic idea of SDHC for plow application will be introduced in this paper and first simulation results will be shown.

Aug 1, 2013

By E. R. Mitchell

When we grow up in an urban environment and choose to become a part of a way of life, it is sometimes difficult to appreciate the cost of this decision in terms of pollution. Explained in this article is our dependence on technology and the amount of pollution that technology produces. Inventories of air pollution on both a personal and a national basis are given so that the reader may judge the magnitude of the problem. In doing so, it is hoped that the reader will understand the need for a responsible attitude toward pollution by everyone and how he can make a personal contribution.

Jan 1, 1971

By Takanori Kokubo, Kenta Suzuki, Tomohiro Sasaki, Toshiya Anami

"Previous work has shown that the strengthening Al-Mn alloys with copper leads to the formation of an undesirable reduction in recrystallized grain size. In this study the mechanisms of strengthening and recrystallization behavior in a continuously cast automotive heat exchanger fin stockof Al-1.1wt%Mn-0.5wt%Fe-0.3wt%Si with a0.3wt%Cu addition were investigated. Metallurgical analysis revealed that the Cu strengthening was dominated by the formation of dispersoid particles, while solid solution strengthening decreased with the Cu additions. This result is attributed to the decrease in the amount of Mn solid solution. The post brazing recrystallized grain size was reduced compared to that not containing Cu. It is postulated that the Cu addition leads to a decrease in the amount of Mn in solid solution which leads to a finer grain size. This effect is attributed to Mn in the aluminum matrix inhibiting boundary migration but allowing other grains to grow during heat treatment. The results are rationalized based on particle stimulated nucleation (PSN), wherein dispersoid particles are more likely to become active recrystallization nuclei during the heat treatment. The increase in the number of active dispersoid particles with Cu addition is correlated to the recrystallized grain structure.INTRODUCTIONImprovements in properties such as strength, braze ability and corrosion resistance in thermal fin stock alloys are all means to gain improved efficiency in heat exchangers particularly in automotive applications. While Al-Mn alloys dominate automotive heat exchanger fin stock alloy, even small chemical compositional changes can profoundly influence these properties (Kawaharaet al., 2004; Yoshino et al., 2009). The microstructure (particularly the grain size and shape) also plays a key role in determining the product performance and hence the thermo-mechanical processing (TMP) must also be considered. The casting method (typically conventional direct chill, DC, or continuous casting) significantly influences the properties in no small part due to the very different TMP routes that are used. Continuous casting is generally favored for fin stock applications as its higher cooling rate (which can be 2 to 3 orders of magnitude higher than DC casting) leads to finer as-solidified intermetallic particles and an increase in super-saturated solid solution elements (such as Mn)that are known to improve fin stock performance such as strength, braze ability(Okiet al., 2008)."

Jan 1, 2018

By N. Ginouse, S. Reny

"In the mining industry time is critical as production depends on the speed of the mining cycle. During the mining process, the time required to re-open access for the next phase of an underground heading is a key point that strongly depends on the ability of the selected ground support technique to promptly ensure the safety of workers. Fiber reinforced dry-mix shotcrete has been proven to be an efficient and well adapted technique, able to produce a ground support material with the required energy absorption or flexural toughness in a single application phase. In this context, this paper demonstrates the possibility of significantly speeding up the mining process by using a new fiber reinforced dry-mix shotcrete. The new fiber reinforced dry-mix shotcrete is capable of developing flexural toughness in only 24 hours that is equivalent to what is typically achieved after 28 days using current fiber reinforced drymix shotcrete technology.INTRODUCTIONShotcrete is often used for ground support when using the drill and blast method or other tunnelling methods. But before re-opening access for the next phase of the underground heading, the applied shotcrete is required to reach a minimum compressive strength and in case of fiber reinforced shotcrete, a minimum flexural toughness (energy absorption) in order to ensure the safety of the workers going into the heading. Combined with bolts, the use of conventional fiber reinforced shotcrete becomes an interesting method for ground support as it is applied very soon after excavation and works to stabilize ground movements (Bernard E. S., 2009). In this case, the toughness development of fiber reinforced shotcrete becomes an important feature of the material when looking to speedup the mining cycle. However, early re-entry criteria in underground openings are difficult to ascertain as the load carrying capacity of fiber reinforced shotcrete is usually assessed after 7 or 28 days. For this reason, re-entry criteria varies from one mining area to another and are usually based on compressive strength requirements. For example, in northern Ontario, Canada, one of the current practices in the mining industry consists of allowing safe re-entry once fiber reinforced shotcrete has developed a compressive strength of higher than 4 MPa (Dufour, O’Donnell, & Ballou, 2003). Flexural toughness requirements on fiber reinforced shotcrete are also typically based on evaluation after 28 days."

Jan 1, 2015

By H Zorychta

Based on underground measurements made at the Nova Scotia coal mines of the Dominion Coal Company, Limited, this paper presents a comparison between the physical properties of hardwood packs and steel friction props when used for longwall support. The probable loads sup-ported by steel friction props on a longwall face at both the Dominion No. 20 Colliery and the Princess Colliery are delineated, and the results of the tests are presented in graphical form. It is concluded that the steel friction props are more efficient than the hardwood packs that they replaced as roof supports. Introduction AN evolution in the methods of longwall face support is taking place in the Sydney coalfield. Longwall face support had consisted primarily of timber props and hardwood packs. In 1957, however, at the Princess Colliery, Sydney Mines, Nova Scotia, the first longwall was equipped with steel friction props. At the present time, eleven longwall faces are supported on wood and sixteen faces are carried on steel friction props.

Jan 1, 1965

By E. B. Spice

"IntroductionExperience at Eldorado has been gained with a variety of mill feeds. That is, the actual mode of occurrence of the pitchblende varies to such an extent that gravity concentration has at times been decidedly unattractive and at others highly successful. Because of this, the type of ore necessary for economic recovery of pitchblende have become well known. Also, those types which do not lend themselves to gravity concentration have become familiar. In general, it may be said that when the pitchblende occurs free, to a large extent, from sulphides or arsenides of high specific gravity, and when the bulk of the pitchblende is localized rather than disseminated, excellent recoveries, high ratios of concentration, and good grades of concentrates , will result from proper gravity concentration. On the other hand, if the ore contains pitchblende intimately or otherwise mixed with large quantities of arsenides or sulphides, or if the pitchblende is finely disseminated, gravity concentration alone will yield high recoveries only at the expense of very low-grade concentrates and low ratios of concentration.According to Taggart, the ease with which gravity separation may be effected is determined by the value of the following ratio: []It is stated that when the ratio is above 1.75, gravity separation can be expected to be easy. Thus with pure U308 (S.G. over 9) and gangue consisting chiefly of siliceous material, the process can he expected to be entirely successful even when carried on at very fine sizes. Unfortunately, the term pitchblende covers a great diversity of material. Although some of the mineral occurs pure enough to have a specific gravity of about 7, the average is much lower than this and is probably well under 5. Some of the pitchblende particles have a specific gravity so low that gravity concentration fails completely. It may also be said that no degree of grinding will produce free pitchblende of sufficient density from such particles. This, then, represents the most important limitation to the application of gravity separation to pitchblende ores."

Jan 1, 1950

By K Byrne, W. Hawker

The average grade of copper concentrate is steadily declining, forcing the industry to turn to lower grade and metallurgically challenging orebodies. When faced with a low grade, challenging ore, mining companies are often forced to choose between high recovery at low grade or low recovery at high grade. Hydrometallurgical processing of copper concentrates using metathesis reactions, which replace iron with copper in copper-iron sulphide minerals and increase the copper to sulphur ratio in copper sulphide minerals, provide an opportunity to upgrade copper concentrates and potentially allow high copper recovery for a high grade concentrate. Factors such as concentrate mineralogy, reaction time and temperature, and the concentrations of copper, chloride and acid in solution are reported to affect the reaction extent and mineral phases formed by metathesis. In this paper, a copper concentrate has been studied over a wide range of conditions to investigate the influence of these key parameters on the extent of copper metathesis reactions and product phases formed. Solution and solid phases are assayed with the main mineral phases identified by Quantitative X-Ray Diffraction. INTRODUCTION The minerals present in copper deposits determine the prospective processing options either: pyrometallurgical or hydrometallurgical. For copper oxide ores, copper is typically present as oxides, carbonate, chlorides, silicates and sulphates. These minerals are readily solubilised in acid and are usually treated through hydrometallurgical processes. The typical process route for copper oxides is to leach copper into aqueous solution, purify and upgrade the solution phase through solvent extraction and then recover copper as metal by electrowinning (Davenport, King, Schlesinger, & Biswas, 2002). Copper sulphide deposits may contain a multitude of copper bearing minerals, including chalcopyrite, bornite, enargite, covellite, digenite and chalcocite. The copper ore grade and treatment options are affected by the mineral type and distribution. Sulphide ores are typically treated through comminution and mineral flotation to form concentrates, followed by pyrometallurgical smelting. Hydrometallurgy can also be used to process sulphides depending on the mineralogy and impurity levels (Davenport et al., 2002). The trend of decreasing copper grade with increasing impurity levels are common across the mining industry and pose future challenges to copper processing. This trend has prompted research into hydrometallurgical options for upgrading copper concentrates. One promising hydrometallurgical option is using metathesis reactions. Metathesis reactions, sometimes also called double replacement or displacement reactions, are chemical processes involving the exchange of bonds between two chemical compounds or species. In this case, the metathesis reactions involve copper in solution exchanging with cations in the solid sulphide concentrate. The driving force for copper sulphide metathesis is the relative affinity of the exchanging cation elements for sulphide. Based on sulphide precipitation diagrams, the expected order of affinity for sulphide should be Hg2+ > Ag+ > Cu+ > Cu2+ > Bi3+ > Cd2+ > Pb2+ > Sn2+ > Zn2+ > Co2+ > Ni2+ > Fe2+ > Mn2+ (Monhemius, 1977). Hence, copper metathesis reactions are capable of increasing copper content and removing impurities such as iron, nickel, zinc and lead from copper concentrates.

Jan 1, 2019

By G. P. Kundargi

India is one of the fastest growing economies in the world. The role of the Iron & Steel industry is very important for the development of the country. Iron and steel are among the most important components required for the infrastructure development of the country. This is one of the fastest growing sectors. The demand drivers for the Indian Iron & Steel industry are increase in the activities of the manufacturing industry and infrastructure development. Indian Iron & Steel industry with its strong forward and backward linkages contributes significantly to overall growth and development of the economy. The industry today directly contributes 2% of India?s Gross Domestic Product and its weightage in the official Index of Industrial Production (IIP) is 6.2%. Manganese is a main ingredient for production of steel. Almost 90% manganese is being utilized by the steel industry worldwide. Globally, there is no substitute for manganese as on date. There is huge gap between demand and production of manganese ore in the country. To meet this demand gap and to support for growth of national economy, MOIL Limited (formerly Manganese Ore India Limited), a Government Enterprises, producing annually around 1.1 million tonnes (mt) of manganese ore and value added products, has geared up with various infrastructural activities to increase the present production capacity of 1.1?1.5 mt in 2016?2017 and 2.2 mt in 2020?2021. The paper deals with the technological improvements and infrastructural development activities of MOIL; this will help MOIL to become the market leader in manganese ore production globally in the coming years.

Aug 1, 2013

By J. R. Gordon

I-Introduction The possibility of adapting low-temperature reduction methods to the treatment of iron ores has been suggested on numerous occasions. Papers published on the subject include, notably, Bulletin 270 of the United States Bureau of Mines on The Production of Sponge Iron, the Symposium of the American Electrochemical Society (1927) on The Gaseous Reduction of Ores and Other Metallic Compounds, and Les Procédés Actuels de Traitement Direct du Minerai de Fer, by A. Mayer (Revue de l'Industrie Minerale, Nov. 15th, 1932) (1). The present paper contains the results of an investigation of the reducibility of some Ontario ores. The concentration of these ores and of the products of reduction has also been investigated.

Jan 1, 1933