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"One of the corporate values mentioned by many companies deals with respect for people. This paper discusses one aspect of this value, namely, the need for clarity of accountabilities and authorities. The job of the manager in achieving this goal is analyzed and the benefits of enhancing the manager-employee conversation outlined. IntroductionCorporate values usually refer to the standards of behaviour that the leaders of the organization expect of all employees, including themselves, in carrying out their duties. Terms such as integrity, respect for the individual, continuous improvement, continuous learning, teamwork, speed, and innovation are quite common. The company-specific values are typically developed by the top executives of the company, and then tested with a broader group of employees. Where the process works, employees have a good understanding of what behaviour is expected of them in doing their work, in making difficult decisions, and in interacting with others.Having spent considerable time in his career investigating and studying the management systems at over 50 of the most successful companies in Canada, the United States, Europe and Japan, the author has had the opportunity to visit organizations such as Hewlett-Packard, 3M, Xerox, Intel, Toyota, NEC, Komatsu, British Airways, and Eastman Chemical. These experiences, together with the work of many other researchers, including the work of Dr. Elliott Jacques, have helped significantly to form the thoughts expressed below.Rather than reviewing the creation of corporate values and their deployment through the organization, these remarks focus on issues over which managers and employees have some control. The value in which managers can have significant impact deals with people and the respect shown them in the workplace. The component of respect to be emphasized is to be clear about expectations or accountabilities for oneself and the people who report to you, and to ensure that personal authority matches those expectations."

Jan 1, 1999

By M. Dworzanowski

The difference in the magnetic properties of minerals is the basis for magnetic separation. All minerals can be generally classified as ferromagnetic (strongly magnetic), paramagnetic (weakly magnetic) or diamagnetic (non-magnetic). Magnetic separation can be conducted dry or wet. The majority of the applications of wet magnetic separation in the mining industry are based on the wet drum magnetic separator. The wet drum magnetic separator has been in use for over 50 years and its design is based on a rotating drum installed inside a tank. Inside the drum are stationary, permanent magnets arranged in an arc to provide the magnetic field. These magnets can be of the ceramic ferrite type providing a low intensity magnetic field or of the rare earth type providing a high intensity magnetic field.

Jan 1, 2010

By D Hunter, N Cusworth, J Miller

"Recent project failures have called into question the use and relevance of benchmarking and independent reviews, forcing a rethink of traditional processes and procedures.With cost estimates and schedules dramatically varying from lows seen around the global financial crisis to peaks experienced in the recent mining boom, benchmarking has ranged between essential and misleading.Profound shifts are now underway in future project delivery strategies as the market moves away from cost-plus engineering, procurement and construction management. The current trends in project implementation are to utilise more lump-sum design and construct or fixed-price supply and construct contracts. This trend will remove transparency in detailed cost information by reducing the sources and clarity of cost data.Independent peer reviews (IPRs) of studies and investment recommendations performed over the last decade have both failed to prevent flawed or deficient projects from proceeding to approval and funding, and been successful in ensuring that owners did not proceed with doomed investments.In recent times, it has been recognised by some owners, contractors and engineers that traditional benchmarking checks or IPRs, or a combination of both, will not necessarily produce reliable assessments of study conclusions and of the forecasts of project outcomes. To be of value, the benchmarking process now also needs to recognise the highly volatile responses from the engineering and construction industry to the current and future markets for their services.Similarly, reviewers who draw upon benchmarks of past project experiences on an understanding of the things that shaped and influenced their outcomes need to be more aware of how a future dynamic market may impact the outcome of the projects and raise warning flags accordingly.With the commodity cycle currently approaching what is hoped is its bottom, ensuring that benchmarking and independent reviews evolve into reliable, transparent and worthwhile processes becomes even more important. This can only be achieved with more transparent and analytical benchmarking and business-orientated reviews that both recognise and calculate the impacts of dynamic markets on project implementation.CITATION:Cusworth, N, Hunter, D and Miller, J, 2016. The role of benchmarking and independent reviews, in Proceedings Project Evaluation 2016, pp 249–259 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016

By Shawn McWilliams, Aini Sun, Mike Lichte, Greg Colzani

The Allegheny County Sanitary Authority (ALCOSAN) adopted its Clean Water Plan (CWP) in May 2020, as part of a federal consent decree to comply with the USEPA’s Combined Sewer Overflow (CSO) Control Policy. Planned improvements include constructing a new regional storage/conveyance tunnel system, promoting green infrastructure/ source control, and expanding the treatment plant. Preliminary planning for the tunnel system was completed in October 2020. The Ohio River Tunnel (ORT) project is the first of three tunnel projects that make up the regional tunnel system. The ORT project began final design in 2021. This paper discusses the advancements made to the ORT preliminary planning concepts considering property availability, alignment optimization, tunnel boring machine evaluation, contract packaging and delivery schedules.

Jun 13, 2023

By James J. Dowd

The investigation to evaluate the reserves of coking coal in the United States suitable for the manufacture of metallurgical coke is being made by the Bureau of Mines in three parts: (1) To estimate known (measured plus indicated) recoverable reserves of all coking coal; (2) to upgrade marginal coals through effective preparation; and (3) to study the carbonizing properties of coals and coal blends not now widely used for metallurgical coke making. This is the fifth of a series of reports giving the results of studies by countless under part (1) of the investigation. (See appendix.) This report covers Westmoreland County, Pa., which comprises parts of New Kensington, Freeport, Elders Ridge, Pittsburgh, Greensburg, Latrobe, New Florence, Johnstown, Brownsville, Connellsville, Donegal, and Somerset quadrangles. (See fig. 1.) A short resume" of the chemical and carbonizing properties of the coals are included. Data on the coal beds in this county were obtained from mining companies, land companies, individual landowners, and other sources of authentic information. A base map for each bed in each quadrangle was made to the scale 1 inch equals 1,200 feet. Maps of mines, locations of drill holes, bed and total coal thicknesses, and the outcrop of the bed were plotted on the maps. With all available data plotted, isopach lines were drawn to limit areas of known unmined reserves in beds up to 14 inches thick, 14 to 28 inches thick, 28 to 42 inches thick, and over 42 inches thick. These areas of coal reserves also were divided into "measured" and "indicated" categories. All areas in each thickness range and in each category, mined-out areas, areas excluded from the estimate, and areas outside of the outcrop were measured by planimeter on the base maps. Estimates of total reserves 14 inches and more thick and maps for individual beds were prepared from these data.

Jan 1, 1951

By Peter Johnson, David Barber, Lachlan Henderson

"The traditional approach to rail tunnel fire safety design is to follow NFPA 130, which assumes a major tunnel fire could occur and requires bi-directional emergency ventilation. There is no regard to the impact of ventilation on fire growth and smoke production. In Europe and other parts of the world, the need for tunnel ventilation systems to provide smoke management in the event of fire is being questioned. The European Commission’s Safety in Railway Tunnels TSI is based on a philosophy that improved running capability (preventing fires and other events stopping the train in the tunnel) and elevated fire performance of materials means the chances of a major fire in a tunnel is highly unlikely, with only small fires expected, and no tunnel ventilation required. This approach is reinforced by the International Tunneling Association which has recently published an Engineering Methodology for Performance Based Fire Safety Design on Underground Rail Systems, which includes a methodology that does not require assessment of tenability in tunnels, but requires a scenario based risk assessment to be undertaken to determine overall fire safety measures. Recent research by the University of Edinburgh has shown that forced airflow from a mechanical ventilation system may promote fire growth and increase smoke volumes much more than with natural ventilation. Whilst the concept of no mechanical ventilation (i.e. natural ventilation) is a new concept for some, for many rail tunnels it is worthy of serious further consideration. RAIL TUNNEL SMOKE MANAGEMENT AND STANDARDS Smoke management using mechanical bi-directional ventilation systems has been a central part of the fire safety design solution under NFPA 130 for rail tunnels since 1982. The current version of the standard, NFPA 130: 2014, states that mechanical ventilation should be fitted to rail tunnels of length greater than 305 meters and an engineering analysis should be undertaken for tunnels of length 61 to 305 meters to determine whether mechanical ventilation should be fitted. However, this approach is not necessarily reflected elsewhere in the world. In Europe in particular, mechanical ventilation systems for smoke control within rail tunnels have taken a much less central role within the standards framework."

Jan 1, 2016

By J. T. Stanley

The identification of crystal phases and crystal chemistry can be critical to understanding the mechanisms of waste material interaction with native soils. Understanding these mechanisms can suggest correct methods for remediation and treatment. A program is outlined and examples are given of the development of effective techniques for rapid phase identification of environmental samples using electron microscopy. The program concentrates on the development of integrated object oriented software to aid rapid searching of online databases and rapid simulation of potential crystal diffraction patterns. Examples come from dried sludge taken from a former hard-chrome plating facility.

Jan 1, 1993

The relationships between Aboriginal Traditional Owners and mining companies have often been mired in dispute, particularly since the High Court Mabo decision and the Native Title Act of 1993. In the Pilbara region, Rio Tinto Iron Ore (RTIO) impacts the traditional country of 12 Aboriginal Traditional Owner/language groups. Over the past 12 years the company and the Traditional Owners have negotiated and settled several significant land use agreements including the Yandi Land Use Agreement over the Yandicoogina mine in 1997, between Hamersley Iron (now Rio Tinto Iron Ore) and three language groups û the Bunjima, Nyapaili and Innawonga people and the Eastern Guruma Indigenous Land Use Agreement (ILUA) of 2006. These substantive agreements are now being followed by a new generation of region wide ILUAs which are close to conclusion. Arising from these regional agreements is a new framework for engagement which has been informed by the implementation of the previous agreements in the Pilbara and across the Rio Tinto group of companies. They are driven by both a company desire to have a consistent approach to engaging with Traditional Owners and the Traditional Owners wanting to have a similarly transparent and consistent standard of performance by the company in implementing the agreements which can deliver improved employment, cultural heritage engagement and direct and indirect benefits for the life of mining by the company. During the past three years the growth in the Pilbara, Western Australia brought new opportunities with people flocking to the region for employment flowing from the mining boom. Housing was at a premium and FIFO (fly-in, fly-out employment arrangements) was developed as a method to manage the general growth and demand for skills. Despite the recent down turn in the world economy since September 2008, which has reduced demand for minerals, the Pilbara continues to enjoy high levels of employment and as a result there is still significant pressure on housing and services provision. Although there has been vast economic growth in the Pilbara not only by mining companies but also oil and gas companies, the 2006 census data indicated that the direct benefits of improved employment, business development and engagement in the mainstream economy continued to exclude Aboriginal people. Indigenous people constitute a significant proportion of the population in the Pilbara region, some 6000 people û currently 14 per cent of the population rising to 18 per cent by 2015 û yet they remain at the bottom of the socioeconomic scale. More than 40 years of mining has returned relatively little to this group of people who are the permanent residents of the region and are connected through their traditional culture to this country (Taylor and Scambary, 2005). Ensuring local Aboriginal participation in the mainstream economy has been a challenge for resource companies, Traditional Owners and local residents in the Pilbara. The case study explores the relationship between a mining company û Rio Tinto Iron Ore and the Traditional Owners of the Pilbara. It examines two projects that have been developed to engage Indigenous people in the development of their region and through regional representation and business development to build a sustainable future for themselves and their future generations and at the same time ensure social cohesion to support social licence to operate. The case study also examines the process that was followed by Rio Tinto Iron Ore and its operations in undertaking a regional agreement for land access, participation and the integration of local Indigenous people into their business and the local economy.

Jan 1, 2009

By Achilles Dutra, Everton Santos, José Oliveira

The beneficiation of phosphate ores by froth flotation is the most efficient process used to separate apatite from gangue minerals like calcite, dolomite and quartz. However, the similarity of surface properties between apatite and calcite generally lead to non-selective adsorption of reagents, rendering the selective separation of these minerals a worldwide problem. The phosphate deposit of Itataia, State of Ceará, Brazil, studied in the present work, presents a complex mineralogical composition having uranium associated with the apatite mineral. The main gangue minerals are calcite and quartz. The bulk flotation of apatite and calcite with anionic collectors in an alkaline medium followed by the selective flotation of calcite at pH 5.5 using phosphoric acid as well as citric acid as depressant have been suggested for this ore. This paper presents the results of contact angle measurements obtained using jojoba oil, a natural reagent composed mainly of gadoleic acid (C20:1) and long-chain fatty alcohols (eicosenol and docosenol), as an alternative collector for the selective separation of apatite and calcite minerals. The hydrophobicity studies were carried out using a computer controlled contact angle goniometer. Additionally, the collector adsorption was evaluated via electrophoretic mobility and FTIR measurements. The results indicated that a high selectivity can be obtained by using jojoba oil as collector in a slightly acid pH range, without the use of depressant. The best results were achieved with a jojoba oil concentration of 200 mg.L-1 at pH 6.5, where the apatite was fully hydrophilic and calcite showed a high hydrophobicity (? > 60 º).

Jan 1, 2014

Sishen uses a state-of-the-art tracking system to track material from its position in blast blocks through various stockpiles and crushers. Qualities are blended directly to the crusher as opposed to blending from stockpiles. This poses an interesting challenge to the planning department to simulate these conditions. The software used in these simulations are Whittle 4X and Maximiser for long-term planning, Xpac for medium-term planning and Mine Works Planner for short-term planning. Geological models and mine design layouts utilise Surpac. Sishen introduced Xpac a number of years ago; the system has developed and changed over the years. With the Sishen Expansion Project (SEP), which aims to utilise low-grade material, major changes to the planning process have to occur. SEP requires that the mine have two different plants, which utilise two different ROM feeds and have different beneficiation curves. Xpac is used to produce a rolling 18-month plan, which is as close to actual operations as possible. In order to do this, the simulations have to take into account the plants beneficiation curves, stockpile movements, hauling distance and equipment needs. On top of this, the schedule has to continually consider specifications for Fe and the contaminants. Plant yields also have to be kept within a certain bandwidth. Xpac is used to simulate the above parameters, as well as generate the raw data required to produce a mine budget. The paper will also show how the 18-month planning process and subsequent planning processes are measured and aligned. Xpac has proved to be an excellent tool to achieve these goals.

Jan 1, 2005

By Tsembel Darjaa, Toru H. Okabe, Yoshiaki Umetsu

"With the purpose of extracting molybdenum and rhenium from molybdenum sulfide concentrate; .electrolysis of slurry, solvent extraction and ·precipitation operations were carried out. The slurry of the concentrate in 10 mass% NaCl aqueous solution was continuously circulated into a vertical type 10 stack bipolar electrolytic cell consisted of carbon electrode disks, and, the concentrate was dissolved by electrochemically generated oxidizers at 313 K. The current efficiency for molybdenum dissolution was 73 % after 10 hours electrolysis, and the leach solution was found to contain 0.2 mol/l of molybdenum and 4x10-5 mol/l rhenium. This result shows the dissolution is more than 8 times faster than that obtained using a single cell. The leach solution from electro-oxidation was then subjected to a solvent extraction for rhenium which is then recovered as sulfides. After rhenium separation, molybdenum was precipitated by pH adjustment, and solid MoO3 (H2O)x crystals, free of sulfate, were obtained from the leach solution containing large amount of so42-.IntroductionIn the past, electro-oxidation using a bipolar cell was applied for leaching molybdenite concentrate and ores at U. S. Bureau of Mines [1-3] and also at Bhabha Atomic Research Center [4]. In· these previous studies, Moebious type bipolar cells, in which electrode plates were vertically inserted into the free surface of the electrolyte, were employed and its effectiveness was demonstrated.Recently, the present authors studied on leaching of Mongolian molybdenite concentrate, and the effectiveness of leaching of the concentrate by electro-oxidation in alkaline and acidic NaCl solutions was demonstrated [5]. The leaching reaction during the process can be explained by the 18 electron transfer reaction of molybdenite (MoS2) with the oxidizers produced in-situ by electrolysis of NaCl aqueous solution. Further investigation was made with respect to various process parameters for electrooxidation such as pH, pulp density and temperature of the slurry, and the dissolution behavior of minor elements such as iron, copper, and rhenium [6]. Solubilities of molybdenum in the leach solution at, various temperatures and pH .was · studied, and feasibility of molybdenum recovery by hydrolysis of molybdenum species was demonstrated. By adjusting the pH of the leach solution, molybdenum oxides or hydroxides free from sulfate were successfully obtained from the solution containing large amount of sulfate ion. Rhenium present in the concentrate at a level of several tens of mass ppm was found to dissolve into the leach solution, and co-precipitate with the molybdenum compounds. Rhenium in the leach solutions, therefore, has to be recovered before precipitation of molybdenum, otherwise it is lost in the precipitate."

Jan 1, 2000

Since the days of Adam Smith and Milton Friedman the discussion of corporate citizenship and sustainability has been flooded with multiple contradictions, with proponents of sustainability saying that it is a crucial cog in the business strategy, while those against, maintain that æthe business of business is businessÆ and therefore sustainability issues are just add-ons. Sustainability arises from a deeply held vision by corporate leaders that businesses can and should play a role beyond just making money. Businesses should embrace the understanding that everything that a company does has an impact both internally and externally (communities, employees and customers), and the natural environment. This paper highlights the approach that led to a view that there is a contradiction between profitability, sustainability and community development, and we provide a further argument to the contrary. This argument is based on a comprehensive literature review of over three decades by various scholars linking corporate social performance and corporate financial performance. Driefontein Gold MineÆs approach is that of linking the community development, natural environmental and employee well-being initiatives and projects to the mineÆs business strategy. The paper further highlights the coordination and implementation mechanism of sustainability at the mine where the accountability lies with the head of the mine operations. A two pronged approach is employed where there is an internal dialogue on sustainability between the various departments coordinated by the sustainable development department and an external tri-sector partnership with local government, interested and affected parties and the mine. These approaches are closely linked to the contributions towards the mineÆs financial bottom line.

Jan 1, 2009

By LeRoy R. Curwick

This Bureau of Mines report presents the results of a study conducted to assess the domestic availability of chromium from superalloy and cast heat- and corrosion-resistant alloy scrap material. Six alloy classes included in this survey were investment cast, hardfacing, and wrought nickel- and cobalt-base alloys, wrought nickel-iron-base alloys, and heat- and corrosion-resistant alloy castings. Data were collected for 1976 on metallic scrap generation, use patterns, and production practices for these alloy producing and using industries. A model was developed that allowed an assessment of the materials flow circuits within the industries that produce these alloys. The types, amounts, sources, secondary products, and ultimate destinations of chromium- containing metallic scrap for the six alloy classes were determined. Regarding the overall recycling efficiency of these alloy producing and using industries, of the 580.9 million pounds of scrap generated from these six alloy classes in 1976, about 72 percent (416.8 million pounds) was remelted by the same alloy-producing industries, about 18 percent (104.9 million pounds) was downgraded into stainless and low-alloy steels, about 3 percent (19.7 million pounds) was exported, and about 7 percent (39.5 million pounds) was lost through landfill or other disposal or service wastage. The lost material is primarily contaminated oxides for which recovery is currently uneconomic. However, the 124.6 million pounds of scrap material downgraded or exported in 197b contained potentially recoverable critical strategic elements. The amount of scrap material lost to the six alloy-producing industries in this manner contained 22.1 million pounds of chromium, 53.4 million pounds of nickel, 5.9 million pounds of cobalt, 35.9 million pounds of iron, and 7.3 million pounds of other alloying elements.

Jan 1, 1980

By K R. Brentley

"Tshepong Mine, Harmony’s largest gold producing mine, is situated in the Free State portion of the Witwatersrand Basin, east of Odendaalsrus and north of Welkom, South Africa. The Basal reef is a narrow tabular conglomerate and is the main gold bearing ore body. The strata strikes mainly in a northsouth direction with an average dip of 22 degrees. Currently mining takes place at depths of between 1 690m and 2 150m below surface. The Basal reef unit consists of a conglomerate ranging between a few and 30cm in thickness. Some 80-90% of the gold occurs in the lower portion of the conglomerate. Directly above the conglomerate is a quartzite placer unit, the Basal quartzite, which is a clean, hard competent rock and varies in thickness between 50cm and 200cm. The Basal unit is overlain by the Khaki shale which can vary between 30cm and 500cm in width. It is weak and incompetent khaki coloured chloritic shale.A method of stoping, termed “undercut”, is practiced in order to remove the lower 15-20cm of the gold rich strata. The method entails removing this portion along with some 70-80cm of footwall host rock which is a strong competent quartzite. The hard competent quartzite overlying the conglomerate is left in-situ to form a competent hangingwall which can stabilize and prevent exposure of the weak Khakishale. This method of extraction was developed through trial and error and has been used reasonably successfully since its inception in the early 1960’s where the method was developed to extract the Basal reef at the Western Holdings Mines. Recently prospect drilling and a number of localised hangingwall failures indicated that the residual quartzite beam could be less than 60cm and in some instances as thin as 30cm in certain areas of the mine. The result of this is a less stable hangingwall which not only poses a safety risk to workers in these areas but also had the potential of locking up some 840 000 Tonnes of gold bearing ore. At the present gold price this amounts to revenue of approximately ZAR1.5 billion (U.S. $143 million).This paper discusses the method of “undercut stoping” and existing practices in place at Tshepong Mine. It also explores new initiatives such as the use of a simple freely-supported elastic beam solution to perform back analysis, on-site data capturing of beam thickness and support geometries in order to develop empirical design charts and numerical modelling to assist in the verification of the empirical design method."

Jan 1, 2015

By R. W. Vander Laan

Conneaut has a long and illustrious history as a major Great Lakes port for coal and iron ore. The first dock was built in 1892 for unloading iron ore from the Mesabi Range for shipment to the Pittsburgh steel mills via the Shenango & Lake Erie Railroad, later to become the Bessemer & Lake Erie Railroad. The Pittsburgh & Conneaut Dock Company was incorporated in 1893. The world's first Hulett automatic ore unloader was constructed at Conneaut in 1899. Steam operated, it was the model for the giant electric Huletts used today, named after its inventor, George Hulett, who was a Conneaut resident.

Jan 3, 1974

By C. F. Ellis

Interest in the composition of automobile exhaust gases has been greatly accelerated by recent studies that have indicated that these gases contribute to smog formation in urban areas. Several analytical methods have been published for the analysis of the hydrocarbons in the exhaust gases, but similar information has not been published on the analysis of the oxygenated compounds. This report presents procedures for chemical analyses of certain oxygenated compounds, procedures for sampling the exhaust gases for these analyses, and the analytical results of some experimental work in which these procedures were used. A stationary 1956 model, 170 horsepower, V-8, dynamometer-mounted engine, operated to simulate vehicular cruise conditions, was used for the study. Exhaust gases produced from a regular-grade Midcontinent gasoline during 15-40- , and 60-mile-per-hour cruise operations were analyzed by chemical methods for formaldehyde, total aldehydes, total carbonyls, total alcohols, carbon associated with the oxygenated compounds, and the oxides of nitrogen. Experimental results indicate: 1. The range of concentrations of the total of the functional groups of oxygenated compounds, expressed as moles per million moles of water-free exhaust gases, is about 90-100; the concentrations increase with engine speed. 2. Aldehydes comprise about 80-90 mole- percent of the total of the oxygenated groups, and formaldehyde accounts for about 50 mole-percent of the total aldehydes. 3. The order of magnitude of the concentration of the carbonyls is the same as that for the aldehydes, indicating that ketones are not a major group. A colorimetric test indicates that methyl ketones Constitute about 2 mole-percent of the oxygenated compounds.

Jan 1, 1961

By LESTER W. STRAUSS

OUR early knowledge of history and geography attracted most of us to the mineral resources of South America. The romantic tales of the Spanish activities, which were curiously alluring, and Prescott's exceptional bi-Conquest histories-Mexico and Peru-no doubt fired our minds with the .then metallic wealth of the Spanish colonies. Later developments, intensified within the past eighty years, have, however, changed its fame which now rests on such metallics as copper and tin, and among the non-metallics on nitrate of soda and petroleum. South America proper, excluding Panama, is made up of thirteen countries, a coincident parity with our original thirteen States. Its area is given as 7,231,300 square miles, or slightly less than North America (8,037,000 square miles), is made up as follows:

Jan 1, 1930

By R. J. Hundhausen

This report describes the exploration and recent utilization studies the Bureau of Mines conducted on the Iron King, Chambers, and Dry Camp chromite deposits in the John Day district, Grant County, Oreg. The field investigations were undertaken during parts of 1939 and 1942 to determine the tonnage and grade of chromite in the district that could be utilized as a war reserve for the steel industry. As a result of the Bureau's field work, which included construction of 9 miles of access road, 6,204 feet of diamond drilling, 195 channel samples, and 1,020 linear feet of trenching, an ore reserve of 208,000 tons of 22-percent chromic oxide was indicated in the 3 deposits. Less than 1,000 tons of this ore has been mined since the field work was completed because the 2 largest deposits are submarginal in grade and there is as yet no incentive to develop and mine the ore. Since the war, however, the Bureau has been seeking means of utilizing the ore. Two methods of utilization that show promise are direct smelting of the ore in an electric furnace and use of the chromite for making refractory brick.

Jan 1, 1956

By M. F. Almeida

"Due to the randomness of all factors influencing the sintering operation, a two-stepped procedure is proposed to find the best way of using stocked fines at a plant producing Fe-Mn alloys for the steelmaking industry. The approach is based on the following: (1) predict the result of the sintering operation by establishing the best multilinear regression model using some of the characteristics of the loaded material; and (2) find the best solution under a minimizing cost criteria by solving a linear optimization problem using the regression equation plus constraints on the feed and product. IntroductionSome tests carried out using 20% to 30% of sinter in the material loaded into a 60 000 KVA Tysland-Hole electric furnace producing Fe-Mn alloys for the steelmaking industry indicated: (1) a meaningful decrease in the off-gas temperature and, consequently, a better energy use due to the material higher porosity; (2) more uniform heat distribution as a consequence of the electrode reaction zone enlargement; (3) an improved furnace control resulting in a smoother operation; and (4) a decrease in gas production facilitating the off-gas treatment. For some years, this plant used only the coarse fraction of the Mn ores, thus stocking all the received and own-generated fine particles. In view of the mentioned results, a strategy for increasing the use of stocked fines was formulated, including a step where it was necessary to decide which components and respective quantities should be used in the blends to be sintered (Almeida, 1984).It is well known that several factors affect productivity and energy consumption in sinter production, also influencing the product quality. Raw materials characteristics, namely chemical and size composition, affect permeability to gases and may or may not allow a deeper bed. In general, finer ores decrease permeability, increasing electricity consumption by fans, but due to their higher specific surface area, react more completely with other components in the mixture. For coke granulometry, a compromise must be obtained in order not to burn it too quickly nor to widen the flame front, therefore decreasing productivity. Decreasing coke in the blend also acts in sinter bonding, decreasing its consistency and increasing crushing and return fines. Moisture addition also influences components mixing, pre-agglomeration, bed permeability and, consequently, sintering productivity. Therefore, optimum conditions must be established for both a given sintering plant and the components in the feed (Dawson, 1993)."

Jan 1, 1998

By L. D. Schmidt, W. C. Schroeder, A. C. Fieldner

"INTRODUCTION The highly mechanized character of modern warfare makes steel the most vital raw material. The shortage of steel scrap in the United States is forcing the use of increased quantities of pig iron in steel manufacture, so that the rate of pig-iron output will continue to be the controlling factor in steel production. 5/ At the same time, the construction of new blast furnaces is limited both by time and the amount of strategic material available. Under such circumstances, every effort must be made to attain and then maintain maximum pig-iron output from the equipment now in use.When forcing a blast furnace to the ultimate in production the highest standards for quality and uniformity of the coke must be maintained. In view of these facts, the Bureau of Mines, in cooperation with the Office of the Solid Fuels Coordinator for War, is surveying the coke industry to study the various steps in producing coke of higher quality and greater uniformity. 6/ The engineers conducting the survey are visiting key men in coke-oven and blast-furnace organizations to determine, first, the major and most common problems in coke production and use; and, second, the best and quickest method for solving them. Various operators have made good progress in solving individual problems, and a Nation-wide exchange of information among them will make possible widespread adoption of the best practices. It is the purpose, of the survey and reports such as this preliminary one to facilitate such exchange of information. As an outgrowth of the survey, it was soon revealed that many operators could be helped by cooperation with various Government agencies, particularly to procure suitable coals, minor additions to equipment facilities, and tests on certain properties of coal or coke, or specific advice concerning the operation of various types of equipment. The machinery and organization necessary for securing this cooperation have been set up as a part of this work."

May 1, 1943