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By H. E. Urtubia

"BHP-Billiton’s Minera Escondida Limitada, in Chile, is one of the world’s largest copper producers. It treats a combined 10,500 tph of copper ore through its two concentrators: Los Colorados and Laguna Seca. The performance of the rougher circuit at each concentrator was measured and analysed using the JKTech flotation optimisation methodology. This involved developing a flotation model for each concentrator based on cell operating parameters (for example bubble surface area flux and froth recovery) and feed ore floatability characteristics. The rougher circuit performance was evaluated in terms of traditional measures, such as grade and recovery. The operation was also analysed using the measured cell operating parameters and ore floatability and the effect of these with regard to performance (grade / recovery) was assessed.This paper presents a comparison of the rougher circuit at each concentrator in terms of these parameters. The main differences in rougher circuit performance between the two plants were attributed to differences in feed ore floatability characteristics and froth recovery. The comparison highlighted opportunities where performance improvements could be made. The study also showed the usefulness of separating the flotation process into easily measurable subprocesses to further identify the different mechanisms occurring in each rougher circuit. Traditional measures like grade and recovery are useful for monitoring flotation operation but this data lacks the depth to determine the root cause behind operational issues. Determining the operating parameters and ore floatability provides the operating plant metallurgist better tools to assess and manage these issues."

Jan 1, 2006

By Glenn K. Nolan

"Today, more than any other time in recent history, aboriginal communities are looking for ways to be understood as more resource development companies continue to explore and develop Canada's vast resource potential.Recent Supreme Court rulings have affirmed the need to engage aboriginal communities early on in resource development projects. There are many conflicting ideas on how, who, and when to engage. Given the large number of communities and varied cultures, each resource development company must equip itself with a better understanding of the people they are planning to work with.The lecture will begin with a basic historical perspective on treaties and the various societies across Canada. We will also explore the current situation many communities find themselves in today. Building a meaningful relationship with a community is the foundation for a lasting partnership. Every community is unique and every approach to engage communities must be just as unique. The lecture will outline some basic steps that can lead to a better relationship building process between the communities and companies."

Jan 1, 2008

By C. S. Maggs, L. Shwydiuk, H. W. Newcomen

The southwest wall of the Lornex Pit at the Highland Valley Copper mine has been experiencing slope displacements since 1978. Measures to manage the displacements on previous pushbacks have included stepping out, scheduling pushbacks to unload the crest of unstable areas, slope dewatering and mining with intensive slope monitoring. The final pushback on this wall is currently being mined and substantial modifications to the slope geometry could prove to be uneconomical. As a result, a campaign of surface water collection and diversion, horizontal drainhole drilling and deep well drilling is currently underway to maintain an acceptable degree of stability to the end of mine life. The various factors contributing to instability, including engineering geologic controls, rock mass strength, and surface and groundwater hydrology are presented. Movement trends, displacement magnitudes and stability analyses results are also discussed.

Jan 1, 2003

By I. Thobadi, C. Pawlik, K. Bisaka, S. Mokoena, M. Erwee

The PyEarth™ process developed at Mintek has been demonstrated successfully at pilot scale. Nine tons of ore containing 2.3 mass % of total rare earth oxides (TREO) from a dormant mineralogically complex iron-rich ore deposit, was subjected to a concentrating smelting step in a 200 kW DC open-arc pilot furnace and the rare earths from the resulting slag were extracted via a hydrometallurgical route. This ore deposit is practically not amenable to extraction by conventional methods. The testwork results proved that the PyEarth™ process was able to optimize the extraction of rare earths while minimizing waste through the removal of iron as a saleable iron alloy. Reduction of iron to the alloy in the smelting step was found flexible, efficient, and controllable, while rare earths were left virtually unreduced in the slag phase. The slag chemistry is selected to optimize both the smelting and leaching performances as well as the alloy composition. Leaching of the resulting slag was found possible and most efficient in hydrochloric acid amongst other lixiviants tested.

Jan 1, 2017

By Mike Dry, Rod Dry

If humanity is truly serious about reducing emissions of carbon dioxide into the atmosphere, today’s power plants burning fossil fuels will have to be replaced by power plants that do not emit CO₂. Unless carbon capture/sequestration becomes practical, the new power plants will be hydroelectric, wind, solar or nuclear installations. Hydroelectricity requires the appropriate geography. Solar installations can only deliver power as and when sunshine is available, and wind installations when the wind blows. Therefore, power from these sources will be intermittent, but the demand for electricity does not follow the patterns of sun and wind. That will require large-scale electricity storage and/or load following by the remaining power suppliers, increasingly so as the use of fossil fuelled power generation declines. Modern nuclear power plants are designed for demand following. However, operating at lower than design output has a negative impact on the economics of nuclear power plants because the overall cost of the electricity they generate is dominated by capital cost. Primary (blast furnace) iron smelting is responsible for a significant part of global CO₂ emissions because the reagent used is carbon. Were it available in sufficient quantity (and at a low enough cost), hydrogen could replace carbon in the manufacture of raw direct reduced iron (DRI), using technology such as modified HYL (Tenova Hyl, 2018) or Midrex (Ravenscroft, 2017). This paper examines a scenario in which, instead of demand following, nuclear power stations are operated at their design capacities and surplus power is used to generate hydrogen in off-peak periods. This hydrogen is then used to replace carbon in the manufacture of raw steel.

Jan 1, 2020

"An innovative concept is proposed whereby the operating power for haul trucks in certain areas of an underground mine are reduced in order to lower ventilation costs. Airflow that must be provided for diesel-powered equipment in most jurisdictions are regulated based on engine peak power capability and engine emissions, both of which can be lowered by artificially reducing the capacity of the engine through the engine control unit. Advances in asset tracking and ventilation on demand enable this methodology and this study demonstrates that it could represent significant value for mine operators. An examination of haul truck duty cycle indicates that de-rating of engine operating power based on the truck’s location in the mine can enable a step change in ventilation rates, often with no material impact on working conditions. Methods for implementation and estimate of cost savings will be defined.INTRODUCTION Ventilation of underground workings remains a significant operating cost burden for modern mine operators. In particular, ventilation rates for underground diesel mining equipment are often defined by local regulatory bodies and are assumed to present minimal opportunity for optimization or savings, at least until battery propulsion systems can be adopted. Commonly, the quantity of air flow required is defined by the peak rated engine output power of diesel equipment. For example, Ontario Regulation 854 SS 183.1 (3) states that “The flow of air must be at least 0.06 cubic metres per second for each kilowatt of power of the diesel-powered equipment operating in the workplace”. Jurisdictions that define air flow using the prescribed CANMET or MSHA ratings use peak engine emissions to calculate air flow required for dilution ventilation. These approaches are similar in that the maximum power capability of a vehicle’s engine is used to define the ventilation rate in all areas where it travels, regardless of what power output is actually used in any of those areas. Examination of the duty cycle of a typical underground haul truck identifies a large variance in the power output of the vehicle depending on its location in the mine and the activities undertaken at these locations. For example, travel on a mining sub-level requires a fraction of the truck’s peak power due to the minimal grade and significantly reduced travel speed. So if we can reliably reduce the peak engine power capacity and engine emissions in areas where peak power is not required, we can logically cut the ventilation rates for those areas."

Jan 1, 2017

By C. M. Bartley

Fluorspar, in addition to its familiar uses as a metallurgical flux and as a source of the electrolyte for aluminum production, has become important as an essential raw material in the rapidly growing fluorine chemical industry. The unique ability of fluorine to react and form compounds with al-most all other chemicals has made it one of the important elements in modern chemistry. Research and development over the past thirty years have resulted in a current annual production of fluorine chemicals that is both technically and economically important to industry. Because many of these chemicals and products are relatively new, and most have properties that are not duplicated by other materials, the present uses are expanding rapidly and new applications are being reported continually. Fluorspar, the only immediate and practical source of fluorine, is therefore an important mineral. This fact has been recognized in major industrial areas such as the United States and Western Europe, but has received little attention in Canada.

Jan 1, 1962

By P. M. Daignault

"Fording Coal Limited is one of Canada's largest producers of metallurgical coal for the export market. Medium- to highvolatile coals are mined at its Fording River operations in southeastern British Columbia. This paper discusses some of the mine design and production related problems encountered, and how they have been resolved. Other aspects of the operation such as geography, geology and standard mining methods employed are also covered.IntroductionFording Coal Limited was formed in 1968 to mine and market metallurgical coal resources held by the company in the East Kootenay region of southeastern British Columbia<1>. The company, at its Fording River operations, holds approximately 19,635 hectares of coal lands, having an estimated resource of 3.5 billion tonnes of metallurgical coal. Total reserves are approximately 520 million tonnes.Fording Coal is owned 600Jo by Canadian Pacific Enterprises Limited and 400Jo by Cominco Limited. Cominco itself is owned approximately 540Jo by Canadian Pacific Enterprises. The company, originally staffed and managed by Cominco, has been independent since January 1978, with its own board of directors, management, staff and employees. The head office is in Calgary, Alberta. The Fording River operations are located in British Columbia, approximately 70 km north of the Crowsnest Pass, near the Alberta/ British Columbia boundary, only 150 km by air and 320 km by road from Calgary.A contract was signed in 1969 with the Japanese steel mills to provide 45. 7 million tonnes of metallurgical coal over fifteen years, commencing in 1972, at an annual rate of 3 .05 million tonnes per year. The mine is presently expanding annual production capacity from the original 3.0 million long tons (3.05 million tonnes) to in excess of 5.0 million tonnes.Concurrent with this production expansion, a vigorous marketing effort has diversified Fording's customers to include additional countries in the Pacific Rim area. Three cleaned coal products are now marketed compared to the single ""standard blend"" product originally shipped to satisfy the Japanese contract. The product specifications are listed in Table I."

Jan 1, 1985

By Edmund C. Bovey

"AS I begin my remarks this morning, please let me say how honoured and gratified I was to receive your invitation to address you here during your deliberations in historic Quebec City. The high esteem in which your Institute is held is reflected in the respect and deference accorded to it by industry across Canada. I feel privileged to be here with you today.I would like to discuss with you some applications of natural gas in the mining industry and suggest to you, in closing, some possible avenues of future development.Natural gas first became avail-able for industrial purposes in Northern Ontario in late 1958. Acceptance of natural gas, as a source of energy by the industry of that area, has been both widespread and gratifying. The mining industry of Northern Ontario has in-creased its annual use of natural gas by approximately 35 per cent each year since 1958. We believe that this trend will continue, al-though we will probably have to accept a more modest 10 per cent annual gain as the market approaches saturation. I would like to explain how we were able to do this and where all this gas is used. Our first sales were largely a matter of price-and the savings we offered were substantial."

Jan 1, 1966

By A. A. Brant

BECAUSE of its simplicity, the dip needle is widely used for locating magnetic rock formations in drift-covered areas. Although it responds only to strong magnetic disturbances, it has the advantage that surveys with it can be carried out rapidly, at relatively low cost, by untrained operators. More accurate surveys can be made with a much more sensitive instrument known as the magnetometer, but this must be operated by a specialist and the resulting survey costs are much higher. Mining men use the dip needle for the location of magnetic ores or mineral deposits associated with magnetic rocks. In certain districts, a survey with the dip needle may aid in solving geological structure. In the Little Long Lac and Crow River gold camps of Ontario, it has recently been used for these purposes. In interpreting the results of a dip needle survey, an understanding of the chief magnetic and mechanical factors determining the dip recorded by the needle is definitely necessary. For example, many observers locate a magnetic body by the highest dip values, apparently unaware that these frequently may not lie directly above the body. It should also be realized that a careful dip needle survey may yield information regarding the dip, breadth, and perhaps depth, of the magnetic body. Moreover, the observer should know when numerous closely-spaced dip readings are necessary, and when the dip may be measured at more widely separated intervals. The purpose of the following article is primarily to describe the factors affecting the registration of the dip needle, with a view to aiding investigators in a more accurate and complete interpretation of their results. To explain the cause of magnetic disturbances (anomalies) and the action of the dip needle, a knowledge of certain fundamental magnetic terms is necessary.

Jan 1, 1938

By C. Gosselin, M. Rheault, M. Benoit, Y. Bouroubi, V. Sarago

The last three decades have seen significant mining development in northern regions of Canada, where the freeze and thaw cycle of permafrost and the corresponding surface subsidence and heave represent a significant challenge to the design and maintenance of infrastructures. Identifying areas at risk is of great assistance to reduce the impact of this issue. Over the past ten years, Synthetic Aperture Radar Interferometry (InSAR) has been widely used to monitor ground surface deformation. With this technique, changes in phase between two SAR acquisitions are used to detect centimeter to millimeter surface displacements over a large area and with high spatial resolution. InSAR can be used as a tool to assist the siting and design of new infrastructure as well as highlighting the risk to existing structures in areas of unstable terrain. This paper presents the results of a project carried out by Effigis, which made use of SAR interferometry in the context of monitoring terrain and infrastructure stability in a northern mining environment that is affected by permafrost seasonal and long term changes. TerraSAR-X images acquired during two periods, August to November 2012 and March to October 2013, were used to measure the deformations and/or movement of ground surface, infrastructure and stockpiles caused by seasonal changes in permafrost extent in and around a mining site located in Nunavik, Quebec. The results showed that spatial and temporal distributions of surface displacements are in accordance with scientific and terrain knowledge. Some displacements were observed in loose soil areas while, as expected, none were detected in bedrock and rock outcrop areas. The areas most affected by active layer changes showed surface subsidence in the thaw settlement period. This study confirms that SAR interferometry has a great potential for operational applications related to risks induced by surface deformation in mining environments. It shows that this technique can be used to produce reliable maps of surface movement and monitor the vertical displacement of important infrastructure.

Jan 1, 2015

By Peter M. Power

A microscopic study was made of a series of simultaneous slag and metal samples taken from a low carbon basic open hearth heat. An attempt was made to identify the various micro-constituents found. As the various impurities in the bath are oxidized, the metal structure changes from that of high-phosphorus white cast iron to that of low.-carbon steel. A detailed study of phosphorus distribution is included. The acid run-off slag has an .acicular orthosilicate structure which changes on &apos;shape-up&apos; to a very basic tri-calcium silicate and calciuim ferrite structure. Many unidentified minor constituents are present in the slags. Though metallography will never replace chemic.al analysis of the bath, the microsopic study of polished slags has some promise of being useful in slag control work.

Jan 1, 1956

By S. Ianos, C. Vibert

Type and shape of large dams founded on rock depend upon the expected deformation of their foundation. Their design consequently requires the assessment of the deformability of the rock mass at large scale. Seismic refraction, laboratory tests on rock samples and empirical formulas can provide an order of magnitude of the deformation modulus, with a limited degree of reliability. Direct in-situ measurement of the deformability of a volume of rock is therefore preferred, which integrate the effect of discontinuities, such as plate loading tests, dilatometric tests, etc. The authors have been compiling results obtained by in-situ deformability tests on a number of dam sites, including the Scarabée (“Petite Sismique”) method. This last method consists in thoroughly analysing the shape of seismic wave forms transmitted through the rock mass. It has been used since now more than 40 years over a large number of dam foundations, and has proved to provide a satisfactory assessment of the static deformation modulus. After comparing the results obtained from different methods on six dam sites, the Authors conclude that their reliability closely depends upon the size of the loading device in relation to the spacing of the discontinuities. Attempts to correlate results from different types of in-situ loading tests reveal difficult, because closely depending upon local geotechnical conditions at test location. Plate jacking tests appear to be the most reliable, because involving a relatively large volume of rock. On the other hand, the Scarabée method (“Petite Sismique”) allows a rapid assessment of the deformation characteristics of the rock mass at large scale, and has been found to provide values generally in agreement with those from plate loading tests, while dilatometric or flat-jack tests were found too dependent upon local conditions. The Authors conclude that preference should be given first to the Scarabée method, which uses light equipment and is quickly performed, together with an accurate geological and geotechnical assessment for interpretation. In a second stage, Scarabée shall be complemented by adequately performed plate jacking tests in selected locations, in order to cross-check results and refine the assessment. The general accordance between the results of the two methods, which both can integrate anisotropy of rock masses, justifies this statement.

Jan 1, 2015

By K. Baris

Methane (CH4) present in coal seams, generally known as Coalbed Methane (CBM), Coal Mine Methane (CMM) or Coal Seam Gas (CSG), is a major energy source, as it is the primary constituent of natural gas. At the same time, released methane is a potent greenhouse gas (GHG) and a major safety hazard in underground mining operations. Therefore, a considerable effort has been undertaken to develop coal bed methane extraction and utilization technologies that can achieve both environmental and safety benefits. Countries with significant coal reserves and gassy seams, i.e., USA, Australia, Canada, China, India, Poland and Germany have developed mature methodologies and practices to extract, before and during mining, and utilize significant amounts of methane from coal seams. Nevertheless, on a global scale, methane recovery remains untested and many technical and economic challenges require urgent attention. The research presented in this paper, sponsored by the United States Environmental Protection Agency (EPA), is focused on the Zonguldak Basin, the only hard coal region in Turkey. The basin is known to contain very gassy coal seams and consists of three major regions: Armutcuk, Zonguldak and Amasra. Among the three, the Amasra coalfield is considered as the most favorable for CBM recovery, as it comprises of deeper coal seams and where a private company, Hema Enerji A.S. (Hema) is already developing coalbed methane production facilities. This study aims at developing a reservoir model to predict the potential CBM recovery from the CBM-2 well, the only producing CBM well drilled by HEMA Enerji A.S in the Amasra coalfield. History matching was utilized to model the 15-day production data and uncertainty analysis was performed to estimate the optimum values for the reservoir parameters. The produced model yielded an average production rate of 143 m3/day for 10 years. The total amount of CH4 to be produced during this period was 0.53 million m3. Furthermore, the total amount of GHG to be avoided was estimated at 6585 tCO2e.

Aug 1, 2013

By T. Lu

Microwaves have considerable potential as an energy source in both mineral processing and metals extraction. In this research, the utilization of microwave radiation for the heating of a gibbsite type bauxite ore was investigated. Firstly, thermogravimetric studies were performed in order to characterize the dewatering processes of the ore. Secondly, both the real and the imaginary permittivities, which are the fundamental properties that determine the interaction of microwaves with any given material, were measured for the bauxite ore as a function of temperature. The changes in the permittivities were shown to be related to the dewatering processes. Subsequently, the effects of operating variables such as processing time, sample mass, particle size, microwave power, sample bulk density and carbon and magnetite additions on the sample temperature in a microwave field were studied. The results showed that under suitable conditions the bauxite ore could be readily heated. Therefore, there is considerable potential for the application of microwaves for the heating of bauxite ores.

Jan 1, 2007

By Matthew Novak, J. Brent Hiskey

It is well known that when chalcopyrite is put in direct contact with copper in an acidic medium a galvanic cell is created. Chalcopyrite is reduced to iron and sulfur deficient defect phases such as bornite, chalcocite, and at very low potentials to elemental copper. Galvanic conversion experiments were performed using three chalcopyrite concentrates. The first chalcopyrite contained less than 10% impurity phases. The second concentrate had a high concentration of pyrite, and the third concentrate had a high concentration of pyrrhotite. The effect of temperature, acid concentration, chalcopyrite grain size, copper grain size, and agitation on the rate of chalcopyrite conversion was studied.

Jan 1, 2014

By J. Y. Murdoch

TAXATION has become a major item in the operation of Canadian mines, and, as such, merits our most serious consideration. I feel it was a splendid idea for the Institute to set aside this time for a frank discussion of this important subject, and believe great benefit will result from a better understanding of the methods and underlying principles involved. Mining, as a great national industry, may quite properly be called upon to pay its fair share of the cost of running the country; and there is no tendency on our part to avoid this responsibility. There is, however, a very definite demand that the proportion be just, and fairly and sensibly applied. I believe that Mr. C. G. Williams, Secretary of the Canadian Metal Mining Association, and others, are giving details of the various Provincial and Dominion regulati6ns, so I shall not touch on that phase of the situation. However, there are some important factors to which I should like very briefly to call your attention. The first is the vital need for stability. As you all know, a considerable period must elapse between the preliminary stages of any mining venture and the time when it comes to production-or is finally abandoned as un-profitable. These early days are fraught with many unavoidable uncertainties. If, to these natural hazards, the apprehension of instability of governmental action be added, the risk becomes so great that capital seeks other and safer fields for investment, and many otherwise promising projects are thus discarded. There probably never has been a time in recent years when so much money was seeking investment as now. Under favourable conditions, the development of our great mineral resources would be a natural and attractive outlet for this money. The amount of taxation which the mining industry can properly absorb is of the utmost importance at this time, and it might be well to consider this question in its relation to the economic stability of our country, for it cannot be too greatly emphasized that direct taxation is only one item in the net return which our governments derive from the mining industry. Indeed, the many indirect benefits are so manifest that it would seem almost unnecessary to enumerate them! We almost invariably think of mine taxation as a direct company tax-overlooking the fact that sales tax, customs duties, acreage tax, income tax on mine dividends, foreign shareholders&apos; dividend tax, and others, must all be taken into consideration. It would seem that the economic value of non-ferrous metal mining in Canada is not sufficiently understood and appreciated.

Jan 1, 1935

By Chris Dougherty

"This presentation will provide a demonstration of the methodology used in designing a modern shaft and hoisting plant utilizing a review of the challenges faced and solutions delivered for the Elk Creek Superalloy Materials Project (Niobium/Scandium). The development of the design required the review of complex hydrogeological conditions, mine production requirements, demanding capital expenditure (CAPEX) limitations and tight schedules. Through an extensive review of various alternatives to satisfy these constraints, the Nordmin Group (including Nordmin Engineering Ltd.) (Nordmin) was able to define a concept and design that addressed risks to the project, met production requirements, cost and schedule constraints and improved constructability. INTRODUCTION The Elk Creek Project, owned by NioCorp Developments Ltd. (NioCorp) presently, will become Nebraska’s first underground metals mine, built to access the Elk Creek Niobium/Scandium deposit. The development of the design for this facility required the review of challenging hydrogeological conditions, mine production requirements, demanding CAPEX limitations and tight schedules. Through an extensive review of various alternatives to satisfy these constraints, the Nordmin Group was able to define a concept and design that addressed risks to the project, met production requirements, cost and schedule constraints and improved constructability. This paper will review the challenges faced, and solutions arrived at in a demonstration of a methodology used in designing a modern shaft and hoisting plant. THE CHALLENGES Nordmin became involved in the project in 2015, invited by the Feasibility Study Consultant to provide input on estimating and layouts for the new operation. Many of the fundamental decisions regarding mining methodology, water handling and production strategy had been made, and the scope of Nordmin’s involvement was very limited in this first engagement. Following submission of that study in late 2017/early 2018, Nordmin had opportunity to discuss the overall effort, and its many assumptions and challenges, with NioCorp’s project team. The dialogue quickly identified several significant opportunities to improve the project construction schedule and costs along with the mine production profile and operational approach while reducing project risk."

Jan 1, 2019

By David D. Davidson

Commodities remain hot for the time being, but for how much longer? The bulls point to global economic growth lead by China?s insatiable demand for raw materials. To further emphasis the bullish view they point to the emergence of India for follow through demand. The bears remain convinced China?s growth is unsustainable and with higher interest rates and high oil prices, the United States economy is poised to slow. Both groups can make a convincing argument and both will be proven right in the fullness of time. Profitability and balance sheet strength for the mining industry has rarely been better. Is this a time to be bold or cautious? In this paper, the author will address the dilemma facing today?s management as they pursue growth and try to minimize risk.

Apr 1, 2005

By Bruno Bussière

Le drainage minier acide (DMA) provenant de la circulation des eaux à travers les rejets miniers sulfureux est sans doute le principal problème environnemental auquel est confrontée l?industrie minière. Afin de prévenir les problèmes environnementaux reliés au DMA, on doit restreindre la présence de l?une et/ou de l?autre des principales composantes menant à la production d?acide, soit l?eau, l?air et les sulfures. Pour ce faire, différentes techniques ont été proposées au cours des dernières années, dont la désulfuration environnementale et les couvertures avec effets de barrière capillaire (CEBC). Dans ce papier, on propose d?utiliser ces deux techniques en combinaison. Ainsi, on produirait un rejet désulfuré à l?usine de traitement qui pourrait, par la suite, être utilisé comme matériau pour la couche de rétention d?eau de la CEBC. Dans un premier temps, on présente les résultats d?une étude de laboratoire qui montre qu?il est possible de désulfurer les rejets de concentrateur à l?aide de la flottation non sélective jusqu?à l?obtention d?un résidu non générateur d?acide. Par la suite, des essais en colonne ont permis de démontrer qu?il est possible de limiter la production de DMA d?un résidu sulfureux à l?aide d?une CEBC dont la couche fine est constituée de résidus désulfurés. Des prédictions théoriques estiment même que la présence de sulfures résiduels dans la fraction désulfurée utilisée comme matériau pour la rétention d?eau peut avoir un effet bénéfique en réduisant la migration d?oxygène. En effet, les sulfures contenus dans la couche de rétention d?eau peuvent consommer l?oxygène qui tente de migrer vers le bas et, ainsi, réduire les flux d?oxygène qui atteignent les rejets réactifs.

Nov 1, 2002