Search Documents

By H. Utsunomiya, Mehdi Sanjari, Abu Kabir, Steve Yue, Jing Su, L. Kestens, In-ho Jung

The microstructure and texture evolution of low temperature rolled AZ31 magnesium alloy during annealing were investigated. The specimens were rolled at the temperature of 100? at a high rolling speed of 1000m/min with a reduction of 30% in one pass. Annealing was conducted at various temperatures ranging from 200? to 500? for different time. To study the effect of fast speed rolling, the same annealing procedures have been applied for the specimens rolled at a significantly lower speed of 15m/min. The microstructure was characterized by optical microscopy and scanning electron microscopy, while the texture was analyzed by X-ray diffraction analysis and electron backscattered diffraction analysis. Texture weakening occurred during annealing at both fast and slow rolling speeds. However, at the same annealing condition, fast rolled specimens always had weaker intensity of basal texture than slow rolled ones.

Jan 1, 2014

By G. Bridgstock, S. S. Forbes, E. M. Elkin

"OPERATIONS at Canadian Cop-per Refiners Limited, since the refinery was established in 1931, have been described in previous papers ( 1,2). Since then the refinery has treated the entire copper output of Noranda Mines Limited and Hudson Bay Mining & Smelting Company Limited. With the commencement of production in 1956 at Gaspe Copper Mines Limited, this copper has also been refined. From the start of operations to the end of 1958, the following had been refined: copper, silver, gold, selenium and tellurium.Construction of new buildings and additions to other buildings have been needed to handle increased receipts. The refining capacity has been increased from 112,000 tons of copper per year to a total of 236,000 tons per year.The refinery is located at Mont-real East, Quebec, close to railway and highway facilities. Incoming materials and shipments, with some small exceptions, are handled by rail. Some finished products are sl1ipped by industrial flatcar to the adjoining plants of Canada Wire & Cable Company Limited and Noranda Copper & Brass Limited."

Jan 1, 1960

By L. E. Puddington, A. L. Mular

"Since the inception of spherical agglomeration, few investigations to exploit commercially the technique in the metallurgical field have been conducted. Of these, none appear to have been carried sufficiently far to demonstrate commercial feasibility.This paper describes a continuous agglomeration-separation process that can rapidly handle large tonnages of ore material. A small pilot plant de-signed from information obtained with the semi-batch unit described herein is currently in operation.In the absence of a reagent recovery system or cheap reagents, the process is probably not economically attractive for many common ores. However, for iron ores, the fuel content of the agglomerates can be used in a subsequent step such as direct reduction."

Jan 1, 1968

By Arnold Blaisonneau, Théophile Guillon, Xavier Rachez, Sylvie Gentier

"L’étude présentée ici vise à étudier l’influence, lors de stimulation hydraulique de puits dans les réservoirs géothermiques de type Enhanced Geothermal System (EGS), du comportement mécanique des zones de failles recoupant le puits sur la réponse hydraulique du réseau de fractures 3D. Dans ce but, un modèle 3D, basé sur la méthode des éléments distincts et dans lequel les zones de failles recoupant le puits sont modélisées par des fractures numériques 2D, est mis en oeuvre. Les modélisations présentées ici visent à caractériser l’influence du comportement mécanique (type de comportement, hétérogénéité) sur la cinétique de la stimulation hydraulique, ainsi que sur son effet spatial autour du puits. INTRODUCTIONPour le développement de l’exploitation géothermique de type Enhanced Geothermal System (EGS), la phase de stimulation conditionne grandement le succés du projet ; en effet, elle a pour objectif d’augmenter l’injectivité et la productivité des puits et doit permettre d’assurer la connexion entre les puits d’injection et de production garantissant ainsi la viabilité technique et économique de l’échangeur. Pour le site EGS de Soultz-sous-Forêts (France), parmi différentes techniques de stimulation, la stimulation hydraulique a été utilisée à cette fin en provoquant une augmentation irréversible de la perméabilité autour des puits. Dans ce type de réservoirs fracturés, le but des stimulations hydrauliques est de réactiver, plus spécifiquement en cisaillement, des structures hydrauliques pré-existantes (fractures, zones de failles etc.) dans le socle cristallin. La compréhension des phénomènes physiques durant la stimulation hydraulique est cruciale pour optimiser cette technologie et pour contrôler/limiter les risques associés (viabilité technique et économique des puits, sismicité induite etc.). C’est notamment le cas pour la relation entre le comportement mécanique des structures stimulées et les conséquences sur le comportement hydraulique dans un contexte tectonique spécifique."

Jan 1, 2015

By L. Rahnenfuhrer

"Hoisting equipment is a vital part of the operation of most producing mines. Safety and continuation of operation necessitates ultrasonic preventive maintenance inspection on a regular basis.Ultrasonic inspection of hoist shafting, brake linkage and draw bars will contribute to a safe operation and can prevent costly unscheduled shut-down time. With little dismantling, ultrasonic testing techniques can be applied to. determine the conditions of shafting and linkage in hoisting equipment, mining equipment and other miscellaneous mining equipment."

Jan 1, 1969

By T. Moyo

Ammoniacal solutions are attractive and effective lixiviants for the dissolution of chalcopyrite, allowing for the formation of stable ammine complexes with copper while rejecting iron. Chalcopyrite dissolution in ammoniacal solutions is reviewed from literature, and results from a recently completed study evaluating it through electrochemical and controlled leach studies are discussed. Ammoniacal leaching of copper ores dates back to 1916 in the leaching of low grade copper ores in the Kennecott leaching plant and in the Calumet and Hecla mines, followed by the commercialisation of the Sherrit Gordon process for the ammoniacal leaching of sulphide copper ores in 1948. Since then ammoniacal leaching has received intermittent focus from researchers with the development of the Anaconda’s Arbiter process and the unsuccessful Escondida process. In these leaching processes, the formation of surface deposits has historically been reported to result in the passivation of the chalcopyrite surfaces, whereas oxygen mass transfer in solutions has been the focus of process design improvements. Results of studies on high grade chalcopyrite material is presented in this paper which show that although a surface deposit was formed, it did not result in the passivation of chalcopyrite in ammoniacal solutions, and that while oxygen transfer is critical, it is not the direct oxidant in the reaction. INTRODUCTION Ammonia and its salts have been used in the hydrometallurgical treatment of non-ferrous metals such as copper, cobalt and nickel from oxide ores. Its chemistry allows for the selective dissolution of desired metals, leaving behind gangue including iron. Chalcopyrite is a copper sulphide ore known to be very stable and hence recalcitrant to many hydrometallurgical processing methods. Thus, the dissolution of chalcopyrite continues to be an attractive area of research. The dissolution of chalcopyrite in ammoniacal solutions is possible due to the stabilisation of copper(I) and copper (II) ions by ammonia in alkaline media. Ammonia has become more attractive as a lixiviant during the present socio-economic climate due to its low toxicity, relatively low cost and ease of regeneration by evaporation (Meng & Han, 1996). Ammonia processes are ideal when the gangue minerals are acid consuming e.g. with calcareous or dolomitic gangue (Paynter, 1973).

Jan 1, 2019

By Steven W. Wilson, Brigitte Lacouture, Nichola A. McKay

"The Aqqaluk deposit is a lead-zinc ore body that lies immediately north of the Main Pit at Teck Cominco’s Red Dog Mine in Alaska. It is scheduled to begin production in 2011 or 2012. A project team was formed in late 2004 to plan and implement an ore characterisation and metallurgical evaluation on the Aqqaluk ore. The main objective of this program was to facilitate the transition from Main Pit to Aqqaluk ore in the Red Dog concentrator. The program will develop a detailed, spatially-oriented characterisation of the Aqqaluk deposit attributes including lithology, ore geochemistry, bulk mineralogy, ore texture, as well as evaluating the metallurgical characteristics of ore hardness, process water geochemistry, bench-scale floatability and mineral liberation in ground feed, concentrate and tails. Developing correlations between the metallurgical response and the ore characterisation data is key to the emerging science of geometallurgy. This on-going program is a technical due diligence study that aims to reduce the risk associated with processing a new ore and to provide predictive information for mining and stockpile preparation.The test work to date has focused on characterising the five ore zones currently identified in the Aqqaluk deposit, namely: Siliceous (sub-divided to High Zn:Fe and Low Zn:Fe), Vein, Median Plate and Baritic ores. It identified a number of challenges associated with surface oxidation, or weathering, of the core samples and outlined a program for future sample collection and storage. Metallurgical testing evaluated ore hardness by a variety of methods. Preliminary floatability studies have been completed and some initial links have been established between the ore characteristics and the flotation response. Soluble mineral weathering products, the relative abundance of pyrite and marcasite and the iron content in the sphalerite grains have all shown a correlation to mineral recovery.As new core is received, both the ore characterisation and the metallurgical testing will be continued with a view to strengthen the existing correlations and develop new links."

Jan 1, 2007

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

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

Jan 1, 2016

By Judy K. Todd

Double benching has been utilized as an excavation technique in open pit mines for many years. This process involves drilling, blasting, and excavating the material for the design bench height. A second bench is then excavated without the creation of a catch bench, i.e. only minimal offset from the first bench face is allowed when drilling off the second bench. The result is a double high bench face or double bench. When drilling off the second bench, the offset of the drill from the bench face projects the lower bench face into the pit up to an extra five meters. This reduces the maximum attainable bench angle, enhances the probability of rock escaping the catch bench and increases the overall strip ratio. The generally utilized process of trim blasting also can impact on the final bench profile by contributing to blast damage of the face. BHP Billiton Diamonds Inc., Ekati Mine Diamond MineTM, has pioneered the usage of a technique that eliminates this offset. Double benching is accomplished by drilling a single, 30m pre-shear (two 15m benches) to define and protect the final bench profile. This article provides a comparison of the attained face angles obtained in the field utilizing both of the above methods, as well as a comparison with the analytically predicted angles prior to excavation.

May 1, 2002

By A. McGrath, M. Trovant, M. Haque

Minimizing energy consumption is a priority for many industrial facilities. Metallurgical and gasification processes produce dirty syngas (CO and H2), which offers the potential for energy recovery. However, syngas handling can pose an explosion risk and even minor leaks can result in poor workplace hygiene. Furthermore, many jurisdictions around the world now discourage wet syngas handling due to limited water availability and secondary pollution. Hatch has developed a 100% positive pressure gas handling system that targets these safety hazards without using fresh water. The implementation of a system for calcium carbide smelters at Qinghai Salt Lake Industry Co. (QSLIC) in China is profiled as a case study.

Jan 1, 2015

By R. Brough

"Over 25 years ago, SKEGA pioneered the use of rubber linings in grinding mills and rubber is today widely accepted and almost standard material chosen for Regrind - and Secondary Hills. There are, however, only a few Primary Hills in operation with ""solid"" rubber linings because available materials and designs are often not cost efficient in comparison with steel alloys on a Cost per ton basis and/or downtime for liner replacement would be to a high.In other words, solid rubber has limits as any other material. However, 'SKEGA started to think, why not try to use the best properties of rubber as well as steel and combine the two materials together.Nearly 10 years ago SKECA started to test this concept in Rod Mills. A steel cap was vulcanized on to the leading face of the lifter bars, to be installed close to the feed end head (fig. 1)."

Jan 1, 1988

By D Reddy Chinnasane

Outline Location of BirchtreeMine and Layout of 124 OB Cut and Fill Mining Background Purpose of the Studies Methodology Results and Analysis Conclusions and Recommendations

Oct 1, 2010

"The Key Lake mill was commissioned in 1983 to process the two Key Lake ore deposits. With the depletion of these ore bodies in 1999, the plant was converted to mill the exceptionally rich McArthur River deposit located seventy eight kilometers northeast of the Key Lake mine site. This paper describes in detail the Key Lake milling process. The mill consists of a grinding circuit, a leachkounter current decantation circuit, a solvent extraction circuit, a yellowcake precipitatiodcalciner circuit, an ammonium sulphate crystallization circuit, and a waste treatment circuit. The paper also describes process changes to handle McArthur River ore, including the ore receiving stationLOCATIONThe Key Lake mill is located 78 kilometres south of the McArthur River mine. It is located at latitude 57' N in northern Saskatchewan, within the southern boundary of the Athabasca formation. The nearest town is Pine House, located 240 kilometres to the south. Access to the mine is by an all weather road and by a private airstrip.HISTORYAND DESCRIPTION OF OPERATIONThe Key Lake mill was commissioned in October 1983 to process ore from the Gaertner and Deilmann ore bodies. The mill was designed to produce twelve million pounds of uranium oxide (U308) a year from a feed grade of 2.4% U3O8.Following grinding, the uranium is leached in a two stage leach circuit using oxygen and sulphuric acid. An eight-thickener counter current decantation (CCD) circuit is used to separate the uranium bearing solution from the solid waste residue. The uranium is further purified in a solvent extraction circuit and then precipitated using ammonia. It is then calcined at 840' Celsius, and packaged into drums for shipping to refineries. There is a crystallization circuit to recover ammonium sulphate produced in the process and a waste treatment circuit."

Jan 1, 2001

By K. K. Feng

"Spontaneous combustion has always been a problem in coal mines and is identified mainly with the mining of low-rank coals. The liability of coals to spontaneous heating is only one of the factors in determining whether spontaneous combustion will occur. However, knowledge of the relative oxidizability of the coal is a useful factor to take into consideration when selecting new coal seams and mining methods for future mine development.Four methods (static isothermal, ignitability, adiabatic and dynamic) have been used to compare the relative liability of Canadian coal to spontaneous combustion and to investigate the mechanism of spontaneous combustion of these coals. Among these f our methods, the static isothermal method is considered to be the best indicator of the susceptibility of various coals to spontaneous combustion. Western mountain coal adsorbs more oxygen and has a higher tendency to undergo spontaneous combustion than the Harbour seam coal of Nova Scotia. It has also been observed that a higher methane content in coal will indicate a lower liability to spontaneous heating."

Jan 1, 1985

By W. J. Weymark

"The Gregg River project is located 40 kilometres southwest of Hinton, Alberta, adjacent to and east of Jasper National Park. This metallurgical coal mine has been developed as a joint venture between Gregg River Coal Ltd. (a subsidiary company of Mana/ta Coal Ltd.) and seven Japanese companies. This 200-million dollar project consists of a conventional truckshovel open-pit operation and a coal preparation plant rated at 2.14 million tonnes of clean coal per year. Mining operations started in October 1982 with plant start-up following in April 1983. Introduction This paper is an overview and update of the Gregg River project, a metallurgical coal mine being developed as a joint venture between Gregg River Coal Ltd. (a subsidiary of Manalta Coal Ltd.) and seven Japanese companies. The Gregg River Coal leases cover 3440 hectares and are located 40 kilometres south of Hinton, Alberta, adjacent to and north of Cardinal River Coal Mine (Fig. 1). This 200-million dollar project consists of a conventional truck-shovel operation and a coal preparation plant rated at 2.14 million tonnes of clean coal per year. A total of 31.5 million tonnes of clean metallurgical coal will be sold to the Japanese over a fifteen-year term. At present, mining operations are ahead of schedule and the plant started up on schedule in April 1983. Access and Climate An all-weather road, Highway 40, connects the minesite with Hinton (the nearest commercial centre) and a Canadian National Railway (C.N.R.) spur line connects the minesite with the C.N.R. main line in Edson. Hinton is accessible by road chartered airline and rail. ' ~h~ rug~ed and varied topography in the area creates large vanations m temperature and precipitation over short distances. The region is characterized by precipitation throughout the year long cold winters and short cool summers. The mean temperatur~ of the area range from a low of -14°C in January, the coldest month, to a high of 12°C in July, the warmest month. Long-term precipitation data indicates a mean yearly precipitation of 870 mm of which 620Jo occurs during the summer months."

Jan 1, 1985

By R. J. Balfour, T. L. Papucciyan

"INTRODUCTIONCapital Cost considerations are basic to feasibility in the achievement of success for Mineral Processing Projects as much as or more than in many other industries. Capital cost is an important factor ae it 1R the unit of measurement for process engineering economic decisions. As a result of ever increasing complexity, alternatives of process and remoteness of site, there is an ever increasing emphasis on accurate estimating and the attendant cost control systems in the international market of today for the Mineral Industry where initial plant costs are becoming a more important factor than operating costs. An undervaluation means trouble ahead. An over-cautious assessment may bring an unnecessary abandonment of a project. Consequently, the ultimate cost must be predicted early and accurately and must be controlled to this parameter during the design and construction phases. Cost Est!~ mating is one of a variety of project management tools used to assist in planning and achieving the optimum balance between Quality, Cost and Time, the eternal triangle of evaluation, namely obtaining a project of acceptable quality at minimum cost and on time. In order to attain these established objectives, proper planning, organizing, coordinating, monitoring, adjusting and controlling the design, procurement and construction elements of the project are essential.This project management approach based upon the principle of a Task Force under single management, comprising a complete service organization, requires a substantial number of qualified individuals specialized in their own field and capable of working together as a team to perform their various functions effectively. The Task Force is supported by their chiefs of discipline and performs in accordance with established procedures and standards under the leadership of a Project Manager.General Engineering Company Limited with the backing of the full resources of Surveyer, Nenniger & Chenevert and its total staff of approximately 1,0009 offers the complete project management service to the Mineral Processing Industry of North America and the rest of the world. As mine sites become more remote and difficult of access, the need for an experienced team of specialists who work under the Task Force principle, with well established standards and procedures becomes even more important. Our long history of successful pro1ecta in this field has been our training ground for the fulfillment of this need."

Jan 1, 1972

By R. A. Rabnett, G. Paget, Patrick Walsh

"Tumbler Ridge, Canada's newest resource community, has been developed differently than have been other resource communities.Since its conceptualization, emphasis has been placed on the establishment of a traditional municipal government at early a stage as possible.Planning f or the community goes back to 1977. By then, extensive study by provincial agencies had shown a new resource town would be required to exploit north east coal. The Ministry of Municipal Affairs, in conjunction with a consultant named R.A. Rabnett began the extensive Tumbler Ridge conceptual plan.The results of the conceptual plan are evident in the organizational and planning goals of Tumbler Ridge. In every aspect from the election of officials to some financial matters, the town functions as a normal municipality. With the resource companies of the North East Coal Development within its municipal boundaries. Tumbler Ridge has been able to debenture its capital projects against its municipal tax base.The town's ability to function as a normal municipality is enhanced by its control over Crown land it has purchased from the province. This gives it further control over the development of the community and helps in establishing agreements with the resource companies and the provincial government to ensure that housing and service needs are met. While resource company representatives sit on certain municipal committees, their roles are advisory in nature.The community continues to move toward full municipal status and will have a fully elected Council by 1986.BackgroundPlanning for the development of northeast British Columbia coal resources began in 1976 under the aegis of the provincial Cabinet Committee on Coal Development. A series of subcommittees were established including a Townsite/Community Development subcommittee. The Ministry of Municipal Affairs chaired this subcommittee and continued as the lead agency for the provincial settlement planning effort over the period 1976 to 1981."

Jan 1, 1983

By K. Yoo

Chalcopyrite is the most abundant copper sulfide mineral, which is normally processed using pyrometallurgical methods (i.e., smelting) to produce copper metal. Smelting has several major disadvantages, such as high gas-handling costs, high capital costs, saturation of sulfuric acid market, and inability to treat low-grade concentrates and to recover some by-products, such as zinc, nickel and cobalt. The development of hydrometallurgical processes for chalcopyrite is desirable to overcome the problems of smelting. Because chalcopyrite is refractory, the leaching rate for chalcopyrite is very low. Therefore, increasing the leaching rate has been extensively investigated, both in sulfate and chloride media, as well as in the presence of bacteria. Chloride leaching processes have shown relatively high leaching rates. The mechanism of the chloride leaching process has been investigated, but the behavior of chalcopyrite leaching in chloride solution is not clear. Therefore, the effect of the solution redox potential on the leaching rate of chalcopyrite in chloride solution was investigated. In the present study, leaching experiments were carried out using 0.1 M chloride solutions and the results indicate that high leaching rates of chalcopyrite can be achieved at relatively low solution redox potentials.

Jan 1, 2007

By J. E. Gill

"The Wasa Lake property is a block of about 1,640 acres in Beauchastel township, Quebec. Gold was discovered there first in 1936 in what is now known as the 'Southern area ( Fig. 1). Stripping and trenching were followed by 9,218 feet of diamond drilling in twenty holes. A number of good intersections were obtained, but their interpretation in terms of ore was difficult. A shaft was then sunk to 220 feet vertical depth. Thirteen hundred feet of lateral work and 543 feet of diamond drilling were completed at the 200-foot level before work was discontinued in 1938. Results up to this point had been just fair.Early in 1944, surface diamond drilling was resumed. The first hole cut material of ore grade in a strong shear zone 1,000 feet north of the old workings, and holes to the east and west showed this to be an extensive gold-bearing zone.In August 1945, a main working shaft was started. This has been sunk to 550 feet slope depth. A cross-cut at 390 feet vertical depth was driven to the ore zone and, by drifting and drilling at regular intervals, a length of 725 feet had been tested to December 31st, 1946 ( Figs. 1 and 2). The results check those from surface drilling quite closely.In the main zone, scoping widths from 8 to 40 feet and averaging about 25 feet are indicated. The grade after dilution should be about 0.15 oz. gold a ton and operation will probably start at 1,000 tons a day."

Jan 1, 1954

By A. L. Craven, J. P. L. Bacharach, D. B. Stewart

"Inert gas use for underground mine fir e control is a well-established mature technology in some parts of the world. This paper reviews three candidate inert gases and describes three case histories where inert gas fire-fighting technology was used in actual underground fires.IntroductionInerting is the introduction of an inert gas into an atmosphere in contact with a fire to reduce the level of oxygen and hence the intensity of the fire 10 the point of extinction. The benefits of inerting include:a. Reduced Explosion HazardBy displacing oxygen from the atmosphere surrounding the fire the risk of secondary gas explosions is reduced. For example, simple methane-air mixtures at standard temperature and pressure are non-explosive below 12% oxygen. In actual mine fires, combustible gases may include hydrogen and carbon monoxide as well as methane. Such gases are also rendered non-explosive with oxygen removal to below 40/0. Fuel-rich oxygen-deficient mixtures can however be made explosive through dilution with air. Such dilution can occur downwind of the fire. It is also important to remember that the atmosphere in a sealed-off fire zone is rarely homogenous.b. Reduced Fire Intensity and SpreadIn a fire zone the initial combustion may well set alight materials surrounding the fire. Inerting can reduce the intensity and spread of secondary combustion and can cool the area surrounding the fire zone after the fire itself has been extinguished.c. Reduced Air LeakageLeakage of air into sealed areas in excess of the natural leakage may be reduced either by introducing inert gas into the leakage paths to replace air or by pressure balancing seals and providing a chamber of nitrogen on the outbye side of the seals. Both methods assist in the reduction of the intensity of combustion and hasten oxygen starvation."

Jan 1, 1986