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By Mingchun Lu, Yunjin Yan

"This paper describes a new type of bell-less top installed on two relined blast furnaces at Tianjin Iron Works and another new-built at Echeng Steel Works in China. A compact installation was presented for existing furnace top innovation with the least reformation of existing top structure. A water cooling and sealing gearbox used for driving the chute discards completely the traditional idea about necessity of continuous supply of cooling gas for the gearbox. A multiring spreader and its dozens of selectable charging patterns enables an operator to achieve optimal burden distribution easily under the condition of a minimum investment of control equipment. Some useful conclusions have been made through a small-size model and a full-scale model tests. The excellent characteristics and the superiority of the new top have been fully proved at both works.IntroductionIt is known that there are some advantages with the bell-less top of a blast furnace: suitable for furnace to operate at high top pressure, capable of realizing optimal burden distribution, less investment and maintenance costs, etc. But why do most of blast furnaces in the world still remain using conventional bell top. One of the concerns is that current bell-less tops still have some shortcomings:1) The height of a current bell-less top might be lower than three or four-bell top or two-bell plus valve seal top, but still much higher than an ordinary two-bell top.2) The gearbox for driving the rotating chute is positioned onto the lip of the furnace. It is subject to attack by crude hot bf gas. Continuously pumping cooling gas (pressurized nitrogen or clean bf gas) into the gearbox is indispensable to withstand such a harsh working environment. Therefore, a plant furnished with blower8 and its ancillaries has to be built, It involves a large sum of investment and much expense in its annual running costs.3) Although the current bell-less charging device as a means of controlling burden distribution possesses a wide range of freedom, it is difficult to realize optimal burden distribution. There are some large blast furnaces realized better burden distribution, but sophisticated control means is indispensable so that the investment of control means is much higher."

Jan 1, 2000

By W. J. Li, L. Kong, G. L. Li, X. M. Xi, J. Qiu

"A novel hydrothermal method was applied to prepare the precursor of LiMn2O4 using pre-treated electrolytic manganese dioxide (EMD) and lithium hydroxide as the main raw materials. The precursor was subjected to heat treatment between 400 and 900ºC to obtain spinel Li1.05Mn1.95O4 and Li1.035Co0.035Mn1.930O4 positive materials for lithium ion batteries. The structure and morphology of the obtained powder materials were studied in detail by means of X-ray diffraction (XRD) and scanning electron microscope (SEM). It is found that the precursor has an amorphous structure and a high reactivity, which is easily transferred to spinel structure during heat treatment, obtaining a positive material with an uniform structure and good performances. The XRD patterns reveal that single phase spinel Li1.05Mn1.95O4 can be obtained from the precursor after heat treatment at 600°C in air. The final Li-rich Li1.05Mn1.95O4 product obtained showed a well-defined stable spinel structure and distinctive crystal faces with particle size between 200 and 300 nm. The as-prepared Co-doped spinel sample exhibited a excellent electrochemical performance with an initial discharge capacity of 113.0 mAh/g and 93.8% of its original value was retained after 100 charge-discharge cycling at 0.5 C.INTRODUCTIONThe increasing demand for portable electronic devices and hybrid or full electric vehicles is driving the development of cheap, efficient, compact lightweight and environmental friendly rechargeable batteries systems (Chung et al., 2002; Scrosati, 1995). Lithium ion secondary batteries have satisfied this demand to a greater degree than other battery systems. The cathode material plays a critical role in the performance of Li-ion batteries. The high cost and toxicity of cobalt compounds for the cathode material of LiCoO2 has prompted a search for alternative materials. LiMn2O4-based spinels offer a potentially attractive alternative to LiCoO2, due to its abundance, low price, ease of preparation, environmentally friendly characteristics, better thermal stability, and its effortless recycling (Tarascon et al., 1991; Yabuuchi and Ohzuku, 2003; Amatucci et al., 1999; Tsai et al., 2003). Some achievements have been created to meet the requirements (Guo et al., 2010; Kang et al., 2005; Park et al., 2008; Takahashi et al., 2006; Lee et al., 2001; Yoshio et al., 2001; Arumugam et al., 2008). However, the largest obstacle encountered in the practical applications of LiMn2O4 is its fast capacity fading during long term cycling, which is due to Jahn-Teller distortion of the [MnO6] framework, the electrolyte decomposition at high potentials and manganese dissolution into the electrolyte (Fey et al., 2003). The electrochemical performance of LiMn2O4 is also strongly dependent on its morphological properties, such as crystallinity, phase purity, surface area, grain shape and particle size distribution, etc. All these morphological properties are closely related to the material synthetic routines and heat treatment processes (Huang et al., 2000; Myung et al., 2000; Takada et al., 1998)."

Jan 1, 2012

By S Shafiee, N Abbate

The evaluation of mining projects requires a methodology that will give flexibility and manage the existing uncertainty within the projects. The discount cash flow (DCF) and other traditional evaluation approaches, which are widely used in evaluating a significant number of mining projects, have simply assumed that the main variables remain constant in their evaluation; elements such as discounted rate, mine life, operating cost and production rate. The DCF ignores managementÆs flexibility to adapt and reforecast and revise decisions. Real options valuation (ROV) is one of the modern evaluation methodologies that provide a tool to adapt and revise mining projects under uncertainty and future variables movements. ROV brings more variables into the evaluation model compared to DCF and assumes them as uncertain and dependent. Finally, ROV provides a range of solutions that can assist in managing this flexibility.This paper endeavours to compare ROV and DCF for mining projects comprehensively and applies these two techniques in the model. The paper shows that ROV will be inclusive of extra value in mining projects due to variables not allowed for, or even ignored, when the DCF model alone is used. One of the significant advantages of the ROV method is being able to evaluate mining projects under different scenarios from the inception of the projects. Furthermore, ROV gives the ability to evaluate the mining project while allowing for abandonment, temporary suspension, or expanding the mining project. In other words, the ROV evaluation process creates an analytical environment, which allows for optimisation of the mining plan within the mining project, as well as the ability to change the capital structure dependant on existing circumstances over the life of the project. The ROV is a new evaluation method that can add value in mining project analysis and offers opportunities to amplify gains, or to mitigate losses. This paper also discusses some of the reluctance to use ROV instead of DCF in current project evaluation.CITATION:Shafiee, S and Abbate, N, 2012. Now, this is the time for mining companies to choose - Real option valuation or discount cash flow, in Proceedings Project Evaluation 2012 , pp 225-234 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

By I. M. Marshall

A review of technical literature covering Canadian mining emphasizes the advancement and changes that have been made in mining practice. However, current technical publications rarely outline basic principles or state definite rules that govern profitable mine operation. it may be argued that the broad principles of mining have long a go been outlined in various handbooks, text-books, and periodicals, and that these principles never alter. This is in great part true, but modern machinery, improved meta1-lurgical practice, and other advances, have in part modified these principles or changed the manner of their application. Many engineers hesitate to state specific rules, because it is so easy to quote an exception to a rules that any such statement appears to lose weight upon its very utterance. The exception to rules, and the reluctance to formulate rules, has forced such maxims as "the only rule in mining is the point of a pick," and "gold is where you find it". As an illustration of rules and their exceptions, one might quote the time-honoured maxim that a mill should not be built before a shaft has been sunk on a property in point of fact, Canadian mining history is replete with examples of wasted capital where a mill was built before a shaft had been bottomed. Y et this past year has seen a property enter profitable production whereon the building of the mill was started before the shaft was sunk. Instances such as this should not be accepted as evidence that a rule has been overthrown, but rather as an exception to the rule. The case cited pays tribute to the application of the diamond-drill combined with the correlation of sound geology. Incidentally, both these features emphasize a modern trend in the development of Canadian mining properties-a trend that is perhaps worthy of further comment. It is such trends that affect the principles of mining or modify their application. It is with such that this paper deals, at ]east in part. It is hoped that the statement of principles and the opinions herein outlined will be of sufficient interest to arouse discussion.

Jan 1, 1939

By H. H. Yancey

In this information circular is presented a summary of the more important articles that nave appeared in the literature pertaining to the experimental work and to the commercial operation of the froth-flotation and Trent processes as applied to the cleaning of fine coal.

Jan 1, 1933

By AIME AIME

R. A. Hadfield, W. H. Bleckly, The Rt. Hon. Sir James Kitson, Bart., M. P.', E. Windsor Richards, E. P. Martin, Andrew Carnegie, Sir Hugh Bell, Bart., Bennett H. Brough. Patrons. Adamson, Joseph, & Co., Hyde; Aird, John, & Co., London ; .Akrill, C., & Co., Ltd., West Bromwich ; Anderson Foundry Co., Ltd.,. Port Clarence, Middlesbrough ;. Armstrong, Sir W. G., Whitworth & Co., Ltd., Newcastle-on Tyne ; As¬sociated Portland Cement Manufacturers (1900), Ltd., London; Babcock & Wilcox, Ltd., London; Baird, William, & Co., Ltd., Glasgow ; Baldwin's, Ltd., Stourport; Barclay, Andrew, Sons & Co., Ltd., Kilmarnock; Barrow Hematite Steel Co., Ltd., Barrow-in-Furness; Bayliss, Jones & Bayliss, Ltd., Wolverhampton ; Beardshaw, J., & Son, Ltd., Sheffield ; Bell Brothers, Ltd., Middlesbrough ; Bolckow, Vaughan & Co., Ltd., Middlesbrough ; Booth, Joseph, & Bros., Ltd., Leeds ; Briton Ferry Works, Ltd., Briton Ferry; Butlin, Thomas, & Co., Ltd., Wellingborough ; Butterley Co., Ltd., Alfreton ; Byrne, James, & Co., Middlesbrough; Cargo Fleet Iron Co., Ltd., Middlesbrough.;. Carnforth Hematite Iron Co., Ltd., Carnforth ; Cochrane & Co., Ltd., Middlesbrough ; Coltness Iron Co., Ltd., Glasgow ; Colville, David, & Sons, Ltd., Motherwell ; Consett Iron Co., Ltd., Consett ; Cooke, William, & Co., Ltd., Tinsley ; Craggs, R., & Sons, Ltd., Middlesbrough ; Darwen & Mostyn Iron Co., Ltd., Mostyn ; Dorman, Long & Co., Middlesbrough ; Dunlop, J., & Co., Ltd., Glasgow ; Ebbw Vale Steel, Iron & Coal Co., Ltd., Ebbw Vale ; Engineer, The, The Proprietors. of, Lon¬don ; Engineering, The Proprietors of, London ; Etna Iron & Steel Co., Mother¬well ; Farnley Iron Co., Ltd., Leeds ; Firth, Thomas, & Sons, Ltd., Sheffield ; Rather, W. T., Ltd., Sheffield ; Fraser & Chalmers, Ltd., Erith ; Frodingham Iron & Steel Co., Ltd., Doncaster; Gjers, Mills & Co., Ltd., Middlesbrough ; Glenboig Union Fire-Clay Co., Ltd., Glasgow ; Glengarnock Iron & Steel Co.; Ltd., Glengarnock ; Guest, Keen & Nettlefolds, Ltd., Birmingham ; Hadfield's Steel Foundry Co., Ltd., Sheffield ; Hall, J. & E., Ltd., Dartford ; Harkness, W.; & Sons; Ltd., Middlesbrough ; Harrison & Co., Ltd., Lincoln ; Head, Wrightson & Co., Ltd., Stockton-on-Tees ; Hill, John, & Co., Middlesbrough ; Hingley, N., & Sons, Ltd., Dudley ; Hopper, John I., Ltd., Thornaby-on-Tees; Hull Forge Iron &-Steel Co., Ltd., Hull; Iron and Coal Trades Review, The Proprietors of, London ; Ironmonger, The, The Proprietors of, London ; Jackman, Joseph, & Co., Ltd., Sheffield ; Jessop & Appleby Bros., Ltd., Leicester and London ; Jes-

Nov 1, 1906

By D. A. Paice

A power supply to operate fluorescent or mercury vapor lamps from 300 volt dc coal mine trolley wires has been developed for the Bureau of Mines. A high frequency regulated inverter unit incorporates ballasts for a mix of lamp loads up to 650 watts. For 600 volt trolley systems an additional power converter unit was developed to step down the dc voltage to 300 volts for the inverter unit. Both units have operated in a working coal mine for over 12 months without need for servicing. The lamp load in these tests included two 100 watt mercury vapor head lamps and six 75 watt fluorescent lamps.

Jan 1, 1979

By Orlando Martino

This regional report covers the mineral industries of Canada and 40 countries and areas in Latin America and the Caribbean Basin. Also included is a brief description of the mineral potential of Antarctica. The Latin American region encompasses an area twice that of the United States. Latin America and Canada have a rich and diversified endowment of mineral fuels, metals, and industrial minerals. Tables 1 and 2 provide a summary view of Latin America and Canada's output of its major mineral commodities in world mineral supply in 1990 and 1991. Table 3 shows the relative importance of a selected group of minerals produced in Latin America in the world mineral economy.

Jan 1, 1993

By Liu Liu

In the recent 10 years the rapid development of Chinese steel industry has attracted the attention of the world. The technological progress of converter steelmaking has played an important role in this process. First of all, slag splashing has been extensively adopted by Chinese steel companies in various sizes of converters from largest to smallest ones, and even including those using special hot metal containing V and Ti. Remarkable metallurgical results have been achieved. Up to now the average converter campaign life has reached nearly 10,000 heats, and the longest exceeds 30,000 heats in three melt shops. Based on this process, the long-life combined-blowing converter steelmaking technology has been developed. Slag splashing has been used to form a gas permeable "slag mushroom" on the top of bottom nozzles to protect the nozzles. In order to keep the effective bottom blowing, furnace bottom thickness control technique has been developed to prevent the furnace bottom growth. It makes the service life of bottom nozzle the same as the converter campaign life (average 10,000 heats and longest > 30,000 heats). The complete combined blowing was ensured through out the furnace campaign. Concentration product [C][0] is in the range of 0.0023 ~ 0.0030%, the T.Fe in the slag is lowered by 4 ~ 6%, and the [0] in steel is decreased by 100 ~ 250 ppm.

Jan 1, 2004

By V. F. Parry

This report is the first substantial description of the carbonizing process and the details of experimental work conducted at the Denver laboratories under a coopeative agreement between the Bureau of Mines and the Texas Power & Light Co. It presents the results of tests on several Texas lignites and other typical western coals that have been processed in the first pilot plant operated at Denver. Investigations on drying fine coal in the entrained and fluidized state have been under way at Bureau of Mines Denver laboratories for several years. Reports on this work were published in 1949 and 19505/ describing the theory and practice of re-moving inherent moisture from the lower -rank coals. The investigation did not include a study of the removal of surface moisture from fine fuel. Private industry in Canada became interested in the possibilities of drying fine coal, employing the closed-circuit system and techniques recommended by the Bureau. Large, commercial-scale drying units were built by a Canadian company, which successfully demonstrated that surface moisture could be removed from fine coal at high efficiency and capacity ill drying units similar in design to those developed by the Bureau.

Jan 1, 1953

By John R. Goode

"This paper reviews options for the separation of a mixture of rare earth elements (REE) into its component elements. Earlier separations used selective chemistry such as double salt precipitation and reductive/oxidative processes – methods that still have a place in the industry. Fractional crystallization was developed for more complete separations of adjacent REE. The latter method was replaced by ion exchange (IX), which was in turn replaced by solvent extraction (SX). Two main SX chemistries are in use, solvation and cation exchangers, with several variants (mixed solvents, ionic liquids, etc.) now under investigation. SX plant configurations have evolved including advanced techniques like “hyperlinking”, novel saponification methods, and alternative stripping techniques. The classic mixer-settler is the most commonly employed device although centrifugal contactors have been pilot-tested. Non-dispersive SX options including microfluidic devices and membrane-assisted SX techniques are being developed and could revolutionize the SX option. Other REE separation techniques now being studied include Molecular Recognition Technology (MRT), Free Flow Electrophoresis (FFE), newer IX systems, and electrolytic processes. Additionally, the classical crystallization and selective precipitation methods and newer bacteria-mediated processes, chloride volatilization, high performance liquid chromatography, and magnetic separation systems have been studied. This paper reviews the options and concludes that conventional SX is the technology of choice but viable alternatives could be demonstrated and acceptable within a couple of years.INTRODUCTIONThe chemical properties of the individual REE are very similar which is why REE minerals and ore deposits almost invariably contain a mixture of all fifteen REE, i.e., La to Lu plus Y. That said, the distribution of REE in a given deposit is frequently dominated by the light REE (LREE, i.e., La to Nd). Examples include the Bayan Obo, Mianning, Lynas Mt. Weld, and Molycorp Mountain Pass deposits where heavy REE (HREE – Sm to Lu and Y) typically account for well under 5% of the REE content. The LREE operations produce some HREE but the main sources of these important elements are the ionic clay deposits of Southern China. Importantly, all of the REE recovery operations referenced above, except for cerianite-bearing ionic clay deposits, initially produce a mixed REE precipitate or calcine with a REE distribution similar to that in the ore (Goode, 2016). However, the consumers of the REE, the manufacturers of magnets, phosphors, catalysts, optical glass, etc., require separated products with purities generally ranging from 99% to as high as 99.9999% depending on the element in question and the end use. Hence there is a need to separate the individual REE one from the other. This paper is intended to review the options."

Jan 1, 2016

By L. Yuan, A. C. Smith

MFIRE, the mine-fire simulation program of the U.S. National Institute for Occupational Safety and Health (NIOSH), is widely accepted as a standard for assessing and predicting the impact of a fire on the mine ventilation system and the spread of fire contaminants in coal and metal/nonmetal mines. MFIRE has been used by U.S. and international companies to simulate fires for planning and response purposes. It is a dynamic, transient-state, mine ventilation network simulation program that performs normal planning calculations. It can also be used to analyze ventilation networks under thermal and mechanical influence, such as changes in ventilation parameters; external influences, such as changes in temperature; and internal influences, such as a fire. The program output can be used to analyze the effects of these influences on the ventilation system. Since its original development by Michigan Technological University for the former U.S. Bureau of Mines in the 1970s, several updates have been released. In 2012, NIOSH completed a major redesign and restructuring of the program with the release of MFIRE 3.0. MFIRE’s outdated Fortran programming language was replaced with an object-oriented C++ language and packaged into a dynamic-link library. However, the MFIRE 3.0 release included no change or improvement to the fire-modeling algorithms inherited from its previous version, MFIRE 2.20. This paper reports on improvements that have been made to the fire-modeling capabilities of MFIRE 3.0 since its release. These improvements include the addition of the t-squared fire as a new fire-source model and the ability to include available heat-release-rate versus time data, the addition of a moving fire source for conveyor-belt fire simulations, improvement of the fire location algorithm, and the identification and prediction of smoke-rollback phenomena. All of the improvements discussed in this paper will be included in MFIRE 3.1 and released by NIOSH in the near future.

Jun 1, 2016

By A G. L Pratt

Change and its relationship with the introduction of new technology is a constant of human history. The mining industry has many examples of this relationship. This record contrasts with its present day struggles to move beyond a public perception of being just ‘dirty, dumb and dangerous’. The drivers for the introduction of new technology are frequently listed as the occupational health and safety of people working in the mines, reductions in direct operating costs, and increases in productivity.This paper discusses the issues that a mining business needs to deal with to implement new technology with the best possible conditions for success. It comments on how the strategic and tactical components of technology planning relate to and interact with change management. The central discussion is directed at the role that people play in the successful implementation of new technology. The introduction of autonomous underground haulage equipment provides a background for the discussion of this topic.The paper uses case study references, equipment supplier information and research findings. The aim is to offer a high-level view of the issues a mine operator needs to consider when approaching the introduction of new technologies for underground mining.CITATION:Pratt, A G L, 2017. Technology change in underground mining – things to consider, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 103–114 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By Mei Long, Tawum Juvert Mbah, Jianhua Zhang, Haiwang Ye

There have been many improvements and advancements in the application of neural networks in the mining industry. In this study, two advanced deep learning neural networks called recurrent neural network (RNN) and autoregressive integrated moving average (ARIMA) were implemented in the simulation and prediction of limestone price variation. The RNN uses long shortterm memory layers (LSTM), dropout regularization, activation functions, mean square error (MSE), and the Adam optimizer to simulate the predictions. The LSTM stores previous data over time and uses it in simulating future prices based on defined parameters and algorithms. The ARIMA model is a statistical method that captures different time series based on the level, trend, and seasonality of the data. The auto ARIMA function searches for the best parameters that fit the model. Different layers and parameters are added to the model to simulate the price prediction. The performance of both network models is remarkable in terms of trend variability and factors affecting limestone price. The ARIMA model has an accuracy of 95.7% while RNN has an accuracy of 91.8%. This shows that the ARIMA model outperforms the RNN model. In addition, the time required to train the ARIMA is than that of the RNN. Predicting limestone prices may help both investors and industries in making economical and technical decisions, for example, when to invest, buy, sell, increase, and decrease production.

Jan 6, 2021

By J A Evans

A well-maintained and low cost mining operation today requires the use of condition monitoring techniques. At ERA - Ranger Mine oil analysis, vibration monitoring, infra-red themtography, and performance analysis have been successfully applied over the last four years to lower operating and maintenance costs. All condition monitoring is scheduled through a comprehensive in-house developed maintenance management system known as the Engineering Information System (EIS). (EIS) is used extensively at Ranger to ensure consistent frequency and recording .of all condition monitoring data. This paper provides an insight into the benefits of condition monitoring and explores the future direction for condition monitoring techniques at Ranger.

Jan 1, 1994

By Fred R. Biggs

This report was prepared by the U.S. Bureau of Mines to present a brief history of the listing of Iron Mountain Mine as a Superfund site on the National Priorities List (NPL) and subsequent remedial actions. The mine area is located on 4,400 acres near Redding, CA, and includes underground workings, an open-pit area, waste rock dumps, and tailings piles. This property involves multiple sources of acid mine drainage (AMD) that are high in copper, zinc, and cadmium. The selected remedial actions, based on the Record of Decision of 1986, would partially cap the Richmond mineralized zone to reduce infiltration of clean water, divert clean surface waters away from contaminated areas, fill surface subsidence areas, and enlarge the Spring Creek debris dam to provide increased surge capacity. Site remediation efforts at Iron Mountain are well into the remedial design-remedial action phase. Costs to date for remedial action are $7.5 million. Details of activities and designs of remedial elements are presented and future activities discussed.

Jan 1, 1991

By Lidong Teng

ArcSaveTM is a new generation of electromagnetic stirrer (EMS) from ABB for electric arc furnace (EAF) operation. Its goal is to improve the safety, increase the productivity and reduce costs. Electromagnetic stirring in the melt bath during arc furnace operation will affect the scrap smelting, bath temperature distribution, refining reactions, and also the tapping practice. This paper has summarized the investigation results obtained from the first ArcSaveTM system installed in a 90 ton EBT arc furnace in USA. The hot test results show that ArcSaveTM has enhanced the heat and mass transfer in the arc furnace process. This results in a faster scrap melting rate, lower slag superheat during arcing, more homogenous melt bath, higher decarburization rate and higher EBT free opening frequency. ArcSaveTM has also reduced the tapping temperature and tapping oxygen in the steel. This brings a higher scrap yield and saves ferroalloy consumption in the downstream ladle furnace operation. The lower energy consumption, short tap-to-tap time, and consistent furnace operation bring increased productivity and safety.

Aug 16, 2017

By A. E. Moss

"IntroductionTHE WORLD-WIDE search for iron ore has been vastly accelerated during the past fifteen years .and Canada is playing a most prominent role in this prospecting boom. During this period, the search for .and development of iron ore deposits in Canada bas proven eminently successful and there is every indication that exploration will continue to be active for many years.This paper has been prepared primarily for the information of those who have bad little or no experience in iron ore exploration. For convenience, it is divided into three parts: ( 1) a brief discussion of the marketing of iron ores, with special reference to Canadian production; (2) a summary of the main features to be considered when prospecting for or evaluating a potential iron ore deposit; and (3) an outline of the methods and procedures used in the search for the direct-shipping iron ores in the Quebec•-Labrador iron ore field.The Iron Ore MarketDue to the tremendous tonnages of high-grade direct-shipping iron ore indicated in the iron ore fields of the Quebec-Labrador and Steep •Rock areas, it might be assumed that there would have been a sharp decline in iron ore prospecting in this country. On the contrary, the development of these two major fields, which must be classed among the world's greatest, has been responsible for much of the current activity. The search for high and medium grade magnetite deposits is being• conducted in many parts of the country and a number of these have reached the development stage. Production is being expanded from the known fields, such as Wabana in Newfoundland and Michipicoten in Ontario."

Jan 1, 1955

The Iron and Steel Committee of the American Institute, of mining and Metallurgical Engineers held a joint session with the American Foundrymen's Association during the Annual Meeting of the Institute in February, 1928, for the purpose of discussing blast-furnace operations and the character of pig iron and castings. Dr. Richard Moldenke presided. H.. H. Sweetser, who was named on the program as the presiding officer of the session, was unable to be present, but sent a letter in which he said: " The meeting we had here last year and the meeting held in Chicago last June showed a desire on the part of blast-furnace men and users of pig iron to get the facts regarding the influence on castings made from pig iron produced in blast furnaces under varying conditions of temperature, mixture and local furnace operations. It has been my hope that at this Round Table we might he able to formulate a series of tests that, would give us the desired information. "Several independent blast-furnace investigations have. been, and still are being, carried on in different sections of the country. The furnaces investigated include a southern furnace, a middle-west furnace, a western furnace and a Chicago district furnace. The results so far show distinct characteristics for each of the four furnaces. It is possible that a furnace in the eastern part of the United States would be different from all the others. "It is hoped that a plan of action can be worked out at your meeting today whereby the IT. S. Bureau of Mines will be able, to carry on more extensive work in connection with the research departments of the different iron and steel companies and the big consumers of pig iron. "No one group can get all of the, information but if the different investigations can be coordinated it will he possible for us to (Iran. conclusions regarding the effects of varying conditions in blast-furnace practice on the pig iron produced and the castings made there from." DISCUSSION R. Moldenke, Watehung, N. J.—I was across the -water this summer and saw some of those interested in an investigation of this kind. 'I'hey told me that in Germany, where they had a joint committee of blast-furnace operators and foundry-

By W. A. STERLING

IN the opencut iron mines of the Mesabi Range in Minnesota, the trend in mining is in the development of mining equipment and mining methods which will move surface overburden and ore-bearing materials with less labor and at a cheaper cost. This is a must for most of the independent operators. Their reserves of direct-shipping ore are extremely small and their operations are being conducted in small, or intermediate pits, with a high stripping ratio in the outer fringes, or shore lines of older pits. and in ore bodies passing from direct shipping to the washing and the intermediate, or retreat ore state. The trend is toward deeper stripping, longer and steeper hauls, and the necessity of moving a total of from three to five or six tons of overburden and ore material for each ton of shipping-grade ore produced. This naturally calls for greater production, with larger shovels, or draglines. cheaper drilling and blasting costs through the drilling of larger-diameter blastholes, and cheaper haulage through the use of trucks of larger capacity and more extensive use of belt-conveyor systems. This trend is notable both in stripping and mining.

Jan 1, 1948