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By Jovanir Francisqueto

O objetivo deste projeto foi elevar a produtividade do pátio de placas do Laminador de Tiras a Quente da ArcelorMittal Tubarão através da alteração do processo de sequenciamento do Laminador de Tiras a Quente com a criação do processo de realocação de placas após a formação da chance de laminação. O trabalho iniciouse com a definição de regras metalúrgicas de realocação de materiais e definição dos critérios operacionais e de atendimento a pedidos para posteriormente ser desenvolvido o software de otimização para a execução da realocação automática de placas na chance de laminação com foco na redução de movimentações no pátio do Laminador de Tiras a Quente. Com a implantação do processo/sistema espera-se conseguir uma redução de aproximadamente 60% nas movimentações de placas para formação da chance de laminação, conforme demonstrado nas simulações com dados reais e consequentemente reduzindo número de paradas de forno em função de problemas de produtividade do pátio de placas visando o aumento da produção do Laminador de Tiras a Quente em torno de 15 Kt/ano.

Aug 16, 2017

By D. S. Yantek, R. J. Matetic, A. K. Smith, E. D. Thimons, J. Srednicki

In a 2007 report to the U.S. Congress, the Office of Mine Safety and Health Research of the U.S. National Institute for Occupational Safety and Health (NIOSH OMSHR) stated that built-in-place refuge alternatives (BIP RAs) provide significant advantages over mobile refuge alternatives. At present, the requirement to locate refuge alternatives within 305 m (1,000 ft) of working faces makes BIP RAs impractical in most coal mines. BIP RAs would be practical if three issues are addressed: (1) allowing BIP RAs to be located at greater distances from the working face, (2) developing a reliable process for the design and approval of BIP RA stoppings that meet the 0.1-MPa (15-psi) design criteria, and (3) developing systems that reliably deliver breathable air to the refuge alternative. In 2015, NIOSH OMSHR conducted a study of these three issues and issued a report. In the report, justification was provided for allowing the placement of BIP RAs at greater distances from the working face than the currently mandated 305 m (1,000 ft), guidelines were developed that could be used by industry when submitting BIP RA stopping design applications for approval which are patterned after the Mine Safety and Health Administration guidelines for coal mine seal design applications, and insights were provided into options for providing a reliable supply of clean, breathable air to BIP RAs. This paper presents a summary of the study’s findings and also addresses issues discovered during the building and designing of a BIP RA that OMSHR researchers constructed in NIOSH’s Experimental Coal Mine in Pittsburgh to research the testing and improving of BIP RAs. These issues include several issues related to the delivery, distribution and exhaust of ventilation air to the BIP RA and some general construction issues that require further investigation.

Jan 1, 2016

By W N. Qin, B Zhang, W Z. Huang, X S Mo

Mengzi Mining and Metallurgy Co, Ltd (MMMC) polymetallic ore contains recoverable amounts of tin, lead, zinc, pyrite and other valuable minerals. With the change in orebody, the run-of-mine (ROM) ore changed from lead zinc rich ore to tin rich ore, where the current ROM ore contains 0.45–1.25 per cent tin, 20–25 per cent sulfur, and 0.20–0.35 per cent copper. The previous processing flow sheet was designed to recover lead zinc rich ore and it is clearly not suitable for recovery of the current tin rich ore, where the tin was already overground and tin recovery was only 50.19 per cent. The Mengzi Mining Company has recently modified the concentrator circuit by incorporating rod mill and high efficient Derrick fine screen. As a result of the improved classification efficiency, the overgrinding of the tin ore was minimised and the recovery of tin was improved by 20.71 per cent, ie from 50.19–70.90 per cent. An additional $10 M revenue per annum can be achieved as a result of the modification.CITATION:Qin, W N, Huang, W Z, Mo, X S, Zhang, B and Wheeler, J, 2014. Application of high efficient fine screen to improve the recovery of tin concentrate, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 487–492 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

1. New publications International minerals/metals review - 1982. Washington D.C., McGraw-Hill, 1983.720 pp. U.S.$1l7. Mining subsidence engineering, by Helmut Kratzsch. New York, Springer, 1983.580 pp. U.S. $63,20. Papers presented at the 6th International Symposium on Jet Cutting Technology, Guildford, England: April 6-8, 1982, edited by H. S. Step hens and E. B. Davies. Cranfield (England), BHRA Fluid Engineering, 1982. £40. 2. Mintek reports Report M95 Modern applications of polarography and voltammetry to inorganic analysis. Report M96 The mathematical modelling of the reduction behaviour of chromite from the Upper Chromitite Layer of the Bushveld Complex. Report M113 The selective flotation of South African chromite. Conference on copper The International Conference 'Copper 83', to be held in London on 1st and 2nd November, 1983, will provide a valuable forum for all connected with the manufacture and use of copper. Underwater mining The 14th Underwater Mining Institute will be held in Madison, Wisconsin, on 7th and 8th November, 1983. Asian mining The Institution of Mining and Metallurgy, in conjunction with the Chamber of Mines of the Philippines, will hold an international conference, Asian Mining '84, in Manila, Philippines, from 6th to 8th November, 1984. Apcom '84 The Eighteenth International Symposium on the Application of Computers and Mathematics in the Minerals Industries will be held in London in the week 26th to 30th March, 1984. The Symposium is being Jet cutting Another Symposium on the very successful and popular series of international conferences on Jet Cutting Technology is being arranged by BHRA.

Jan 1, 1983

By E. D. Stephenson

As part of the British Steel Corporation?s development plan during the 1970?s, it was decided to concentrate its bulk steelmaking processes based on the BOS at 4 major Works with access to deepwater ore terminals, for the supply of high-grade imported ores. These 4 sites were at: - 1. Rarenscraig Works in Scotland where the ore terminal would be hilt at Hunterston on the west coast some 50 miles away. Bavenscraig was already an integrated Works but suffered from having to discharge ore 27 Glasgow tenxinus on the River Clyde, which could only accommodate vessels up to 25,000 tonnes. In the future, ore was to be unloaded at Runterston and shipped by a rail-link into Ravenscraig, The new ore terminal would have the potential to unload vessels up to 300,000 tonnes. - 2. Port Talbot Works in south Vales where the existing harbour was developed to discharge large ore carriers. This again was an existing Integrated Works and the benefits of the new harbour also applied to Llanwern Works which was another integrated Works some 50 dies to the east, which would now receive ore from Port Talbot.

Jan 1, 1980

Jan 1, 1886

By P Holtham, K Duffy, W Valery, A Jankovic

In the face of increasing energy costs, limited water resources, more stringent legislation, and lower feed grades, the mining industry is searching for more sustainable technologies and practices. Metso Process Technology and Innovation (PTI) is undertaking a research project, ‘improving the resource and eco-efficiency of mining operations’, to help the industry meet these challenges. The project is investigating alternatives in mining and processing that reduce energy and water consumption, minimise emissions and waste, and maximise the value recovered from the deposit. The targets are to reduce energy usage by more than 30 per cent and greenhouse gas emissions by more than 50 per cent compared to current practice.Key areas of interest were identified across mining and processing operations. These were grouped into the following interrelated work areas for investigation: high intensity selective blasting, in-pit crushing and conveying, preconcentration, energy efficient comminution circuits and technologies, coarse particle flotation, and water recovery optimisation. Investigations have included reviews of industrial data, modelling, simulation, and laboratory and pilot scale trials. In some areas industrial scale trials will commence shortly. This paper discusses the investigations and key findings from the project so far; highlighting the possibilities for reducing energy consumption, water usage and carbon emissions. A particular mining process may incorporate any combination of the alternatives identified and requires tailored solutions based on a detailed understanding of the ore deposit, the process and local conditions. The focus is on improving resource efficiency; creating more value with less impact and consequently a better economic return from the available resource. Technologies exist today that can transform mining into a more efficient industry for tomorrow.CITATION:Duffy, K, Valery, W, Jankovic, A and Holtham, P, 2015. Resource efficient mining processes of tomorrow, in Proceedings Third International Future Mining Conference, pp 227–238 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By C. Hudson, D. Tremblay, A. Frey

"A discussion of the design, challenges and successes associated with the commissioning of the gravity recovery circuit at Canada’s newest open pit gold mine - Atlantic Gold’s Moose River Consolidated Project in Nova Scotia, Canada is presented. An overview of the project, its historical significance and overall flowsheet is provided with special focus given to the design and selection of the gravity circuit equipment including the scalping screen, gravity concentrators and the novel intensive leaching technology selected for the project. The performance of the gravity circuit is benchmarked against the feasibility study process design specifications and the outcomes are discussed. Challenges encountered during commissioning are also presented, including the use of third-party automation and the effects of screen sizing on overall gravity circuit performance. Mechanical modifications made to the Sepro Leach Reactor for the Moose River project are also discussed. A detailed technical review of the mechanical and operational aspects of the Sepro Leach Reactor is provided with key operational data on leach times, recoveries, reagent usage, solid-liquid separation, pregnant solution quality and its influence on bullion purity.INTRODUCTION Atlantic Gold Corporation’s Moose River Touquoy Mill in Nova Scotia, Canada was commissioned in the fourth quarter of 2017 with commercial production declared in March of 2018. The 2 Mtpa process plant uses a conventional, gravity-CIL process. This site was previously mined in the 1870s. Interest waned in the early 1900s but resumed in the 1930s and the mine was brought back into production in 1935 until an underground mine collapse in 1936. This mining district became famous after CRBC radio commenced a ground breaking, around the clock, broadcast of the rescue operations. Over 100 million people listened to the broadcast from Canada, the United States and the United Kingdom. These broadcasts changed radio, transforming it from a medium for music to on the spot, breaking news reporting. The mill was constructed by Ausenco on a fixed price EPC contract in the historic Moose River gold mining district, 95 km north-east of Halifax by road. The mill will process ore from the adjacent Touquoy pit for the first 5+ years of operation; after the Touquoy reserves are exhausted, the mill will process ore trucked 37 km from the Beaver Dam deposit for an additional 5 years."

Jan 1, 2019

By K Haroon, J D. Speed, S P. Wood

Online analysis of continuous and batch processes has seen a dramatic increase in recent years, with examples ranging from petrochemicals to pharmaceuticals, to industrial biotechnology and food and drink. The particularly challenging environment of alumina processing has meant that instrumentation needs specific features and characteristics to be truly suitable, features such as: robustness, resistance to caustic conditions both in the analyte and the ambient environment, and reliability for long-term continuous use. Here we present the development of a novel FTIR spectrometer that achieves these requirements through the use of a static optics arrangement of mirrors, and stable diamond-tipped light-pipe probe. Firstly we give a very brief explanation of spectroscopic analysis, and the difference between FTIR and other infrared methodologies. Next we outline the novel arrangement of mirrors required to produce an interferogram without moving mirrors, and compare the benefits and drawbacks of this approach instead of conventional designs. We then share the results of laboratory analysis of synthetic Bayer liquors, with detection limits for aluminium hydroxide, sodium hydroxide, sodium carbonate and various sodium salts of organic acids. We then share the results of analysis on production samples, both in idealised laboratory conditions and then online in the process itself. Lastly we present work on in situ ultrasonic descaling solutions to avoid scale build-up and provide continuous cleaning of the probe – preventing the need for probe removal and manual cleaning.

Aug 24, 2022

By Shibayama A.

In this research, an investigation of a process to selectively remove arsenic (As) and antimony (Sb) contained in enargite (Cu3AsS4) and tennantite/tetrahedrite ((Cu1,Fe)12(As,Sb)4S13) copper resources by leaching and precipitation were performed. First in the leaching process, the target was to selectively leach As/Sb and reduce their contents in the ores to <0.5 wt% followed by a second process to remove As/Sb dissolved in solution for environmental control. Enargite ore contained 3.65 wt% As while tennantite/tetrahedrite ore contained 5.40 wt% As and 4.85 wt% Sb. Alkaline leaching using NaHS?NaOH media at varying experimental conditions (temperature, pulp density, time, reagent concentrations) were performed to investigate the process. As/Sb precipitation studies were also performed to control high As/Sb concentrations in leach solutions by using elemental sulphur (So). Results from leaching studies showed that over 99% of As/Sb in the impure copper ores can be removed and their contents in the final solids reduced to <0.5 wt%. It was also established that such very high leaching could be achieved at 80°C within 1?6 h and pulp densities as high as 1000 g/L. The study also revealed that leach solution containing very high As/Sb concentration ranging from 5 to 20 g/L can be used as fresh solution for leaching of fresh ores until concentrations exceeding 35 g/L when it was sent to precipitation circuit for As/Sb removal. Addition of elemental sulphur at 90°C and fast cooling to 30°C allowed over 60% As/Sb precipitation and removed as Na3AsS4 and solution with reduced As/Sb concentration to leaching circuit for continuous use. Keywords: Enargite; Tennantite/Tetrahedrite; Selective Leaching; Precipitation; Sodium hydrosulfide;

Sep 1, 2012

As 1979 drew to a close, it was obvious that China would have another good year with output of most industrial products at 3-9% above levels attained in 1978. Most increases were registered on the basis of maximum utilization of existing capacities and nationalization of procedures and methods. There were also distinct improvements in the quality and variety of products. Coal output probably surpassed the 650-Mt level in 1979. Steel output was expected to reach the 35-Mt level, an increase of nearly 10% over 1978. Based on the vast amount of housing and road and project construction, cement production more than likely surpassed 70 Mt. The nonferrous base metal industries improved somewhat in 1978, but actual output levels in recent years may have been a little higher than previously estimated by the outside world. Stagnate world demand slowed growth in the "export metals" sector. Minerals like magnesite and talc were produced at tonnages much larger than previously thought, with gold also falling into this category. Sulfur and pyrite production are still short, although a big pyrite mine was being brought into production. Barite out-put was reportedly up and fluorspar output held its own. Westerners generally concede that difficulties in transportation and power supply are holding back mineral production. Throughout 1979, basic construction continued on the majority of projects started by the Chinese and those few foreign projects contracted before the adjustment of industrial priorities. Foreign Ventures Perspective The foreign connection looms large in China&apos;s plan for modernization. In effect, it is an extension of what China wants to do in terms of "walking on two legs"-that is, develop what can be done locally to the fullest extent, then rely on international technology to move into the bigger and more complicated projects. Foreign projects are designed to complement domestic projects rather than replace them. Many foreign projects were started or continued by the Chinese in 1979. Building the necessary infrastructure for the projects is usually a Chinese endeavor and requires Chinese technicians and money. In areas with a strong economic base, this activity proceeds without foreign aid. In other areas, added funds are requested. Foreign funds can come in many forms-equipment technology, low interest loans, equity capital, advance-of-funds on the basis of future delivery in kind, and joint venture money. The Chinese are exploring all these avenues, with the strategy of minimizing foreign exchange needs for individual projects. They feel very uncomfortable with high interest rates, even though interest can be treated as operating ex¬pense rather than capital expense. Then there&apos;s the question of rights. Will Chinese sovereignty be affected? Can foreigners own land, in addition

Jan 3, 1980

By Mark S. Sanders

The purpose of the present study was to develop and test improved Type V workvests for use on dredge operations. The goal was to design workvests that would be more comfortable to wear, would interfere less with task performance, and would better meet the needs of dredge workers. It was hypothesized that by attaining these goals, the resulting vests would be worn more often and would be kept buckled more of the time than traditional vests. The study involved three major phases. In Phase I, visits were made to dredge operations and a definition of the problem was developed. Problems with current vests were identified and working conditions and tasks surveyed In Phase II, prototype vests were developed and laboratory tests were per-formed to assess comfort and interference. In Phase III, the prototypes were modified and field tested with actual dredge operators and workers.

Jan 1, 1985

By J T. Carswell, N A. Schofield

Fluctuations in periodic reconciliations between the mine and the mill are an expected and common experience in mining and processing operations. These fluctuations are caused in part by errors in the estimates of tonnage and grade of the mined material as well as errors in the millÆs assessment of the material processed. Keeping these errors small and unbiased is an important aspect of an efficient operation whose primary goal is to derive maximum benefit from the exploitation of the mineral resource.These fluctuations in periodic reconciliations can also mask subtle but economically important problems which may take years to identify and resolve. Such problems can result from a poorly-conceived model of the mineralisation which affects both the spatial distribution of the ore as well as the tonnage - grade distribution over the range of cut-off grades. Poorly conceived models of the mineral resources and ore distribution can arise as a result of insufficient and inadequate?drilling and sampling of the mineralisation, inappropriate?application of geological?constraints in the estimation process and the use of inappropriate methods to estimate the block grade distribution. This paper presents three case studies from gold and copper mining operations, two of which experienced significant problems with their mine to mill reconciliations over extended periods of time. For the gold mine in case study 1, sampling problems were ultimately considered to be the main cause of the poor reconciliations between grade control predictions and the mill which persisted over a period of 18 months. In addition, incorrect application of resource modelling methods contributed significantly to a mismatching of the mill capacity with the mine at the beginning of operations. For the underground copper mine in case study 2, a change in the approach taken to resource modelling brought marked improvements in ore definition and more accurate predictions of ore grade and better production forecasts.The third case study describes the background to the expansion of production to exploit a large tonnage of lower-grade stockwork mineralisation in an open pit gold mine. Several years of favourable Mine to Mill reconciliation data from the mining and processing of higher grade and lower grade stockwork styles of gold mineralisation provided the confidence in the approach to grade control to support the expansion plans during a period of low gold prices.The paper is intended to complement the discussion of mineral resource estimation methods and risks in Section 6.1.3 of the Mine ManagersÆ Handbook to be published by the Australasian Institute of Mining and Metallurgy (Schofield, 2012).CITATION:Schofield, N A, Moore, J and Carswell, J T, 2012. Mine to mill reconciliation - Three case studies, in Proceedings International Mine Management 2012, pp 161-172 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

By Roney Eduardo Lino, Loyslene Rabelo Fernandes, Gustavo Henrique Sousa, Athos Fernandes Araujo, Wallace Crisólogo Souza Gonçalves

Nos processos de refino dos aços, as ferroligas exercem um papel muito importante. E deve-se conhecer o comportamento do rendimento dessas ligas para que não sejam feitas adições desnecessárias que possam elevar os custos de produção ou até mesmo acarretar em perdas de corridas por composição química fora da faixa de especificação. Nesse trabalho foi utilizado o simulador de refino secundário do Steel University para avaliar o comportamento do rendimento das principais ferroligas em estação de rinsagem com banho metálico desoxidado ao alumínio e em banho não desoxidado. Foi possível avaliar que o comportamento do rendimento das ferroligas tende a ser mais positivo quando se é feita a desoxidação do banho metálico utilizando Alumínio briquetado. Com isso feito um comparativo do custo de produção que mostrou que, quando se conhece o comportamento dos rendimentos, é possível gerar economia para o processo.

Oct 1, 2019

By Victor Costa de Mello Vasconcelos

O objetivo desse projeto é a preparação nanofolhas de óxido de níquel por calcinação e a formação de híbridos com nanopartículas esféricas de ouro e paládio. O trabalho focou na síntese de materiais com forma e tamanho controlados por meio de metodologias simples e ambientalmente amigáveis e na preparação de estruturas híbridas com dispersão uniforme entre componentes. Foram obtidos hidróxidos, óxidos e híbridos, cujos parâmetros de síntese (como temperatura, tempo de reação, entre outros) foram estudados. Uma vez caracterizadas, empregaremos as estruturas do tipo M/NiO (M = Au, Pd) como catalisadores nas reações modelo de oxidação do álcool benzílico e de redução do 4-nitrofenol, com o intento de estudar a natureza da interação metal-suporte.

Oct 30, 2017

By Evandro Tolentino

As fibras vêm sendo empregadas nos materiais de construção civil desde o início da humanidade. No começo da década de 50 houve o início da utilização de fibras de aço no reforço de matrizes de cimento. Com isso foram notadas alterações no comportamento do material, sendo detectado o aumento da tenacidade pós-fissuração. Esta é uma pesquisa experimental que teve como objetivo a definição de parâmetros de ensaios para a produção de argamassas de cimento Portland, que utilizem fibras de sisal nas suas composições, tratadas quimicamente por acetilização com intuito de reduzir a absorção de água. O sisal (Agave Sisalana) apresenta boas propriedades físicas e mecânicas. As fibras foram cortadas manualmente nos comprimentos de 20 mm. As diferentes composições de argamassas foram produzidas com 0,2% e 0,4% de fibra de sisal, em relação ao volume total da argamassa. Estudou-se o comportamento mecânico dos compósitos com ensaios de resistência à tração na flexão. Os resultados mostraram uma melhoria na resistência à tração na flexão para argamassas com fibras tratadas quimicamente por acetilização.

Oct 30, 2017

The capability for on-line measurement of the quality characteristics of conveyed coal now enables mine operators to take advantage of the inherent heterogeneity of those streams and split them into wash and no-wash stocks. Relative to processing the entire stream, this reduces the amount of coal that must be washed at the mine and thereby reduces processing costs, recovery losses, and refuse generation levels. In this paper, new approaches for optimal control of the segregation process, using time series models and empirical distributions, are presented and demonstrated using field data.

Jan 1, 1998

By Bráulio Campagnaro Santana

Na indústria da mineração, a liga Fe-Cr-C destaca-se como um revestimento duro em chapas de desgaste objetivando aumentar a vida útil do ativo. Três ligas, duas delas contendo Fe-Cr-C, sendo uma com aproximadamente 28% (p) de Cr e outra com 38% (p) de Cr e uma terceira liga com 24% (p) de Cr e 7,0% (p) de Nb foram levadas a ensaios de desgaste abrasivo roda de borracha conforme norma ASTM G65-04, além de medições de dureza, microdureza e caracterizações microestruturais. Constatou-se que os revestimentos contendo Nb, depositados com uma ou duas camadas de solda, possuem maior resistência ao desgaste abrasivo, seguidos pelos com maior teor de Cr. Os revestimentos que possuem maior fração volumétrica de carbonetos, finamente distribuídos na matriz, apresentaram os melhores resultados na resistência ao desgaste. Analisando no microscópio confocal 3D os revestimentos contendo Cr, notou-se que os mecanismos de desgaste são do tipo microcorte e microssulcamento, enquanto naqueles contendo nióbio prevalece o desgaste por rolamento em boa parte da superfície. A liga contendo Nb apresenta o melhor desempenho na resistência ao desgaste abrasivo em relação às demais, e se torna viável economicamente sua aplicação na indústria.

Oct 30, 2017

By Graham Davey

"Ultrafine grinding of minerals has been in wide spread use in the industrial mineral field for over 30 years. Within the last 10 years the metalliferous industry has shown interest in the ability to produce ultrafine particles, as chemical, physio-chemical and physical separation processes have advanced to be able to treat ultrafine metalliferous particles. Also as the primary mineral deposits are depleted, new more difficult deposits must be mined. Existing operations are also looking to maximize economic return from existing deposits, requiring new thinking and technologies.The recent development of industrially proven and cost efficient technologies for ultrafine grinding has opened up another processing option for the treatment of finegrained metalliferous and refractory gold ores. The current commercial designs are variations of stirred mills used in the industrial minerals sector for the past 30 years. For the purposes of this paper ultrafine grinding is considered to be P80 of less than 15 microns.Attrition milling to fine grind sizes presents some challenging issues relating to scale-up including the dearth of information on the quantitative impact of feed and operating conditions, as well as the precise and accurate measurement of particle size distributions. Two examples from recent installations will be analyzed including Thalanga Copper and Century Zinc Mines. Both have diverse grind size targets for the SMD, yet both have realized significant metallurgical gains."

Jan 1, 2002

By William W. Odell

Certain gas-making processes are in use in Europe, particularly in Germany, which differ radically from those in common use in America. A number of them are of particular interest because they are different. The questions naturally arise: Are any of them applicable to the making of gas in this country and, if so, with what particular type of solid fuel? It is a fact that some of them were developed with consideration of a particular set of conditions and for the utilization of solid fuels available in Germany. The latter fuels, in certain characteristics, are unlike the high-rank fuels commonly used for making gas in the United States; therefore, in attempting to evaluate the various foreign- developed processes with regard to usefulness here, one must give attention to the particular conditions that will prevail in any specified case and also the characteristics and requirements of the process and generator under considera- tion. Three of the processes that were developed and put into commercial operation in Germany, and which have some characteristics in common, are con- sidered in particular in this publication; they are: 1. Lurgi pressure gasification process. 2. Winkler process. 3. The Leuna slagging-type producer-gas process. Each of these processes requires steam and oxygen as gas-maiding fluids. For a number of years, oxygen, has been used in a relatively pure state,. along with steam, in making gas in Germany, and many of the difficulties initi-. ally encountered have been overcome. Although it appears that oxygen recovered from air was first used in this manner as a method of utilizing a byproduct in a plant that used the nitrogen complement in the manufacture of ammonia; more recently, the oxygen was made particularly for the purpose. The fuels - brown coal or lignite used in processes 1 and 2 were not suitable for use in the older and commonly used intermittent-type water-gas generators, and it was necessary, therefore, to devise a different process for gasifying them. A gas of higher heating value than producer gas, was desired, and the use of oxygen (not air) along with steam made possible the production of the desired gas without nitrogen dilution, which characterizes producer gas. Operating data presented herein are based upon observations by, members of the Technical Oil Mission at plants in Germany, on records, and on information vocally given to members of the lässion, including the author, while visiting those plants, and they are believed to be reasonably correct; however, certain hasic observations, comparisons, and conclusions are. made by the author.

Nov 1, 1947