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By D. R. Spink

An historical background is presented to provide a basis for the lack of normally expected developmental effort over the first 20-25 years of viable zirconium production operations. This is followed by a description of developing technology, which is the result of years of research and piloting effort directed to the development of a more economical method to produce high-grade metallic zirconium. It is predicted that many of the process improvements described will have a significant impact on future zirconium production methods and consequently on future prices and markets.

Jan 1, 1977

By Dwayne D. Tannant

The Adra tunnel near Naramata BC experienced a fire in 2010 that burned timber sets within the tunnel and caused severe spalling of rock from the roof and tunnel walls. The nature of the damage is documented and efforts completed to rehabilitate and open a portion of this tunnel to the public are described. The use of shortcrete and rock bolts is a technically and economically superior support system to timber sets as well as being far more fire resistant.

Jun 1, 2012

By K. C. Sole, G. Robinson, M. S. Moats, W. G. Davenport, S. Sandoval

Global practice in hydrometallurgical production of copper cathode by electrowinning is reviewed, based on individual plant operating data for 2018. Data from 29 plants were collected, representing 38% of world cathode copper production. Similar surveys were carried out in 1997, 1999, 2003, 2007, and 2013. This survey includes analysis of historical and current data. Evolving trends in operating conditions and performance, as well as equipment design and process technology choices, are analysed and differences in operating practices with location are assessed. Examples of recent technology and operational choices to increase productivity, improve copper quality, and decrease electrical energy consumption are discussed. Significant project expansions, particularly in Africa, and the consolidation of numerous small Chinese operations are also presented. INTRODUCTION Global trends and operating practices in copper electrowinning (EW) in 2018 are reviewed and evaluated. Similar world and African surveys were carried out in 1997, 1999, 2001, 2002, 2003, 2007, and 2013 (Robinson, Davenport, & Jenkins, 1997; Jenkins, Davenport, Kennedy, & Robinson, 1999; Davenport, Jenkins, Robinson, & Karcas, 2001; Robinson, Garbutt, & Davenport, 2002; Robinson, Davenport, Jenkins, King, & Rasmussen, 2003; Robinson, Davenport, Moats, Karcas, & Demetrio, 2007; Robinson, Sole, Sandoval, Moats, Siegmund, & Davenport, 2013). Contributing operations included sites from the USA and Mexico (9), Chile and Peru (6), Laos (1), Kazakhstan (1), and Africa (9). Despite fewer contributions compared with past experience, this survey nevertheless represents 2018 copper EW cathode production of 1.76 Mt, or about 38% of world production of 4.64 Mt (International Copper Study Group, 2017). This drop in permission to contribute is attributed to the more competitive nature of the industry and unprecedented production pressures; furthermore, several operations in Australia have shut down, while large operations that are currently commissioning or ramping up to full production in Africa and Asia declined to participate. Of the Chinese operations, which represent an increasingly important proportion of global electrowon cathode copper, particularly in Africa, only Tenke Fungurume (Democratic Republic of Congo; DRC) participated in this survey.

Jan 1, 2019

By F. C. Lendrum

Introduction The property of Normetal Mining Corporation is in Desmeloizes township, Quebec, twelve miles north of Dupuy on the main line of the Canadian National railway from Quebec city co Cochrane, Ontario. The ore bodies occur within a band of highly sheared and sericitized agglomerate which strikes N.60°W. and clips 82° north. Along a zone 1,000 feet or more in length and of variable width, the agglomerate has been replaced by copper, zinc, and iron sulphides, with copper usually predominant on the hanging-wall side and pyrite replaced in part by sphalerite on the footwall. A northsouth diabase dyke cuts through the ore zone near its east end. The Normetal mill produces a copper concentrate and a zinc concentrate which are shipped, respectively, to Noranda, Que., and Newcastle, Penn., U.S.A., for further treatment. The present paper deals with the milling of ore from what is known as No. 3 orebody. This is a lenticular body of high-zinc ore lying co the east of the diabase dyke, along the line of strike of the main ore zone, which extends westward from the dyke. On its northern side, No. 3 orebody is in contact along most of its length with a narrow band of copper ore which is highly oxidized.

Jan 1, 1948

By Descarreaux. Jean

"The Abitibi volcanic belt was sampled along a cross section extending from Matagami to a point east of Rouyn. A few samples were also collected in Louvicourt township, Quebec. The major elements were determined for 344 samples, and rock names were defined using normative minerals. The analytical data were studied by means of variation diagrams. The Abitibi volcanic belt is characterized by rocks belonging to both the tholeiitic and calc-alkaline magmatic series, but they show some differences as compared to some typical reference series, particularly those from Japan. Basalt is the predominant rock type and accounts for 44 per cent of the sampled outcrops. The volcanic rocks are relatively poor in K2O and TiO2. Regionally, the volcanogenic copper-zinc mineralization is associated with the calc-alkaline volcanic sequences. Locally, within such sequences, some types of abnormal deviations from the averages are recognized only in association with the copper-zinc mineralization. The anomalies are ascribed to hydrothermal alteration consisting of the introduction of MgO and removal of N a20; enrichment in K20 is also observed where zinc mineralization predominates. Examples of such anomalous zones show that, in places, this alteration phenomenon can be quite extensive. Petrochemical characteristics can be used as geochemical ore guides in exploration programs."

Jan 1, 1973

By E. Ghali

"Corrosion of support system components (e.g., bolts, mesh, plates) is a safety and economic concern in underground mines. This paper reports the results of a five-year study wherein corrosion coupons were installed at select locations in participating mines, recovered at regular intervals, analyzed for signs of corrosion, and tested to quantify loss in capacity. Complementary tests were conducted on recovered mesh and friction bolt specimens. The data provide insights into contributing factors for support systems corrosion, which aid in the selection of appropriate support strategies and reliable assessment of the useful life and need for rehabilitation of a support system.RÉSUMÉ La corrosion des composantes des systèmes de soutien (p. ex. boulons, grillages et plaques) est une préoccupation économique et de sécurité dans les mines souterraines. Cet article présente les résultats d’une étude de cinq ans pendant laquelle des coupons de corrosion ont été installés à des endroits spécifiques dans les mines participantes; ces coupons ont été retirés à des intervalles réguliers, analysés pour des signes de corrosion et mis à l’épreuve pour quantifier la perte de capacité. Des essais complémentaires ont été effectués sur les grillages récupérés et sur les échantillons de boulons d’ancrage. Les données aident à comprendre les facteurs qui contribuent à la corrosion des systèmes de soutien, ce qui est utile dans le choix de stratégies appropriées de soutien et pour une évaluation fiable de la durée de vie utile et du besoin de remise en état d’un système de soutien."

Jan 1, 2015

By D. Yuan, M. Sitter, S. St. Jean, M. Collins

The Ambatovy Joint Venture comprises an operating lateritic nickel mine, ore slurry pipeline, pressure acid leach plant and nickel refinery in Madagascar. The hydrometallurgical process selected by Sherritt for treatment of the Ambatovy ore is a long-term, sustainable approach to producing nickel. Sulphur, used to prepare hydrogen sulphide, which is used to produce mixed sulphide intermediate, is recovered in the refinery as ammonium sulphate fertilizer. Additional sulphur is used to generate sulphuric acid for treatment of the ore in the high pressure acid leach (HPAL) step; fossil fuel consumption is minimized by using the heat generated from the exothermic reaction between sulphur and oxygen in the acid plant to produce power and steam. Steam consumption is minimized by design of efficient flashing and preheat systems for HPAL, while the high temperature of the HPAL step serves to minimize acid consumption. Fossil fuel consumption by the operation as a whole is further minimized by locating the leach plant and refinery near the port of Toamasina and utilizing a 220 km slurry pipeline to transport ore from the mine to the leach plant. In addition, Ambatovy has demonstrated a strong commitment to sustainability programs such as the biodiversity management program at the mine and local procurement in Madagascar. In this paper, the hydrometallurgical process for nickel and cobalt recovery from Ambatovy ore is described, along with highlights of Ambatovy’s approach to sustainability in Madagascar.

Jan 1, 2015

By I. Tinto

"IntroductionEnvironmental pollution problems, caused by gases or effluents, by high noise levels or from air borne dust, are placing increasing demands of the operators, from statutory authorities, and from the general public, to adopt more stringent dust control measures. This requires that a successful plant dust control program be an integral part of any plant operation. While a successful environmental program is a key factor in maintaining productivity and good labour relations, anticipation of future environmental regulations during the plant design phase can avoid the high cost of plant upgrading, or dealing with pulmonary conditions in the work force in subsequent years.Particulate removal, conventionally called dust collection, involves the removal of coarse- and fine-particulates from the airstream. Although generally limited to that required for contro!Hng plant generated air emissions, particulate control equipment also has a wide application for air cleaning and filtration inside the plant, as well as for recovery of usable products.In the late 1950s and early 1960s the public became more concerned with the problems of air pollution. This increasing concern was stirred by an awareness of the extremes to which water pollution had progressed in many of the rivers and lakes, by increasing perception of air pollution as detected by visible smog and harsh chemical odors, by the alarming rate of increase of smog plagued cities and communities, and by specific incidents where ill health could be traced to specific episodes of air pollution. Particle size is perhaps the most important single factor affecting particulate control. Large particles (over 5 microns) constitute the major mass fraction of most sources of emission and economical control equipment dqes exist for their efficient control. However, while these larger particles frequently represent the source of soiling and unsightly smoke plumes, they are not a major health problem as they tend to settle relatively quickly, are more easily scrubbed from the atmosphere by rain, and are not able to penetrate the respiratory system. By far the most important form of particulate air pollution is the fine particulate, (below 3 microns) which is harmful to the pulmonary system. The adverse effects caused by this particulate matter on human health are for the most part related to injury to the surfaces of the respiratory system. Particulate material in the respiratory tract may produce injury itself, or it may act in conjunction with gases, altering their sites or their modes of action. A combination of particulates and gases may produce an effect that is greater than the sum of the effects caused by either individually (i.e. synergistic effect)."

Jan 1, 1989

By B. Yu, S. Kelebek, C. Gibson, M. Aghamirian

There are a number of high grade niobium deposits worldwide which have been deemed untreatable by flotation due to the very fine grained nature of the in situ pyrochlore, the primary niobium bearing mineral. A known method of recovering extremely fine particles is through the use of chelating reagents such as hydroxamic acids which have a strong affinity for transition metals. However, one of the major issues in the flotation of niobium bearing minerals using hydroxamic acids is the corresponding recovery of other transition metal gangue minerals including magnetite, hematite, and pyrite. In order to better understand the differences in behavior of niobium and iron bearing minerals in flotation with benzohydroxamic acid (BHA) and sodium hexametaphosphate (SHMP) at a range of pulp temperatures, a Box-Behnken experimental design was employed. Regression models for the global recovery of iron indicated that iron mineral recovery was significantly influenced by both BHA and SHMP dosage. Upon examinination of flotation products by semi-quantitative XRD, it was observed that recovery of iron oxide and sulphide minerals (hematite, magnetite, goethite, and pyrite) was problematic at high benzohydroxamic acid dosage, while sodium hexametaphosphate was mainly helpful for carbonate mineral depression. Iron rich carbonates (likely an iron rich dolomite) largely reported to the tails with increased SHMP dosage.

Jan 1, 2015

By A. Lawson

"Continued and expanded use of underground diesel-powered equipment is considered desirable in order to achieve necessary production capability, particularly when coal becomes increasingly in demand as an energy source. Although diesel engines are derated for underground use, concern has been expressed in many quarters regarding the health effects of worker exposure to diesel-generated particulate and NOx emissions. This concern will increase as Canadian diesel fuel quality becomes heavier and with higher sulphur content. This could result in a requirement to increase ventilation rates by 50%.This paper describes the results of studies of various approaches designed to reduce diesel emissions. Two major approaches have been followed: fuel modification, and emission control hardware development. The results of progress in the development of these approaches will be described.Fuel modification includes the application of water/diesel and methanol/diesel fuel emulsions to the engine. Details of the techniques employed in this approach will be described, together with the effects on diesel emissions. (The paper is concerned with the emission aspects only, not the possible major engine modifications and/ or substitute materials of construction for 100070 methanol.) Use of methanol has the added advantage of acting as a diesel fuel substitute and extender, and there are expectations that underground diesel engines could eventually operate on close to 100% methanol fuel, thereby eliminating particulate emissions. The results of emission control hardware development will also be presented and will include the effects of catalysts, water scrubbers, exhaust filters and exhaust gas recirculation techniques on emissions. A combined systems approach employing a number of these components appears to be the most viable method of controlling the complete array of diesel emissions.This work should culminate in a better understanding of the costs involved in employing fuel modification or emission control hardware relative to the costs of increased ventilation which mpy be necessary to maintain a safe working environment for the underground worker."

Jan 1, 1981

By M. Tiedtke, T. Crary, P. MacPhail, M. Ounpuu

"The SGS carbon-in-pulp (CIP) / carbon-in-leach (CIL) model was used to evaluate and optimize the carbon circuit at Alamos Gold’s Young-Davidson Mine. Plants samples (pulp and carbon) were tested in a series of small scale batch experiments to determine rates of gold leaching and adsorption on carbon from a combined flotation concentrate/tailing product. The testwork data, along with existing plant data were then used to model the performance of the existing CIL plant and optimize the circuit to improve performance and overall recovery. The primary purpose of the modelling exercise was to determine the most cost effective way to lower solution losses at the plant. The modelling was also used to learn how the various parameters in the CIL circuit affect solution losses and the gold inventory tied up on the carbon. This resulted in recommendations for minor changes in the CIL flowsheet, which were successfully implemented in the plant. The approach, results and plant changes are presented.INTRODUCTION This paper presents the details from testwork conducted on samples from Alamos Gold’s Young- Davidson gold mine which is located near the town of Matachewan, approximately 60 km west of Kirkland Lake in Northern Ontario, within the southwestern part of the Abitibi Greenstone Belt. The objective of the test program (completed by SGS Canada in 2013) was to investigate and model the combined flotation concentrate / tailing carbon-in-leach (CIL) circuit and suggest ways to improve gold recovery. The metallurgical test program included mineralogy, rheology, and carbon modelling testwork. Plant information was provided during the test program and used in the optimization process. Upon completion of the testwork, plant changes were recommended and implemented at site (October 2014). Plant results from 2014 to 2017 confirmed the modelling results."

Jan 1, 2018

By Michelia Alba, Ronaldo S. Sampaio, Davi S. Braga, Mathieu Dubé

Climate change is pressuring industries and governments for decarbonization commitments, research, testing, and use of best practices to achieve the target of global warming below 1.5/2 °C. As it accounts for as much as 7% of all global CO2 emissions and 7% of energy consumption, the steel sector needs to address this issue with extended efforts. This paper provides information on the key potential of renewable biochar as an alternative fuel for pellet production. It also summarizes the successful application of biochar in a pioneering case study as the main fuel for a Grate-kiln pellet plant in Brazil, as well as the study of its use to replace coke and anthracite as an additive for iron ore pellets and other possible applications in the steel industry in COREM's precompetitive research & innovation program. The final discussion reveals the large quantity of biochar required by the Brazilian and Quebec scenarios for reducing CO2 emissions of iron ore pelletizing plants.

Jan 1, 2023

By Chris M. Healey

"Abstract- The Jasper Gold mine in northern Saskatchewan produced a total mill feed of 140 127 tonnes at an average grade of 19.0 g/t Au. Both diamond drilling and chip samples from under­ ground workings returned extremely high values, up to 12 851 g/t (375 oz/I) Au over 0.10 meter from a chip sample. In the presence of such extremely high grades, the accurate estimation of reserves is a major problem.ln the first part of this study, production data from the mine were used to evaluate the results of a variety of reserve estimation techniques in this environment. In two out of three cases studied, indicator kriging with assays cut to 342.9 g/t (10 oz/I) gave extremely good results. In the third case, however , indicator kriging gave unacceptable results. Instead, lognormal kriging of uncut data gave the best results.Secondly, from the same database, a number of drill-hole spacings were simulated, and reserves estimated from the simulations. As may be expected, the results of this analysis show increasingly better results with tighter drill-hole spacing. However, even with a 5 m by 5 m spacing the variation from actual grade was quite large. This is not a systematic under- or over-estimation of grade, rather a random scatter of results .The results of this study show very clearly the problems of deriving good estimates of reserves when extremely high-grade samples are encountered. There is a high degree of randomness to this database, so reserve estimation in this situation will remain a high-risk operation."

Jan 1, 1993

By Wei Sun, Xiangsong Meng, Xiaodong Li, Weisheng Huang, Yuehua Hu, Chonggao Cao, Haisheng Han, Wensheng Chen, Runqing Liu, Central South University

"The similar flotability of scheelite, fluorite, and calcite resulted in the difficult separation by flotation. This work revealed the effect of water glass on the flotation of scheelite by FTIR and the wettability change of the usual cleavage plane, and proved that water glass inevitably influenced the flotation of tungsten minerals to a large extend in traditional fatty acid flotation process. A new collector, benzohydroxamic acid complexes, was found to be selective for the separation of scheelite and calcium minerals with little water glass. Hence a novel flotation process was developed for the recovery of tungsten minerals in shizhuyuan mine in China. Normal temperature flotation of tungsten minerals was developed to instead of the classical “Petrov's process” for scheelite-calcite-fluorite type ores. Compared with the traditional process, the recovery was improved by 10% and the grade of scheelite concentrate was above 55%. The disappearance or decreasing of water glass contributed to improving the recovery of tungsten and fluorite and the circulation of water and reagents.INTRODUCTIONChina is rich in tungsten resources and the proved reserves accounted for 60% of the world's reserves (Cai Gaipin et al., 2009). However the wolframite has been dried up and the scheelite resource has become the main resource of the tungsten metal. Scheelite deposits were classified to scheelite-silicate type and scheelite-calcite-fluorite type based on the associated gangue minerals. Scheelite was easy to separate from the silicate minerals. Flotation separation of scheelite from calcium minerals creates difficulties because of the existence of the same cation in the minerals and similar physicochemical characteristics such as solubility, hardness, specific gravity, PZC (point of zero charge) etc.(Arnold & Warren, 1974; Yongxin & Changgen, 1983; Ozcan & Bulutcu, 1993a; Deng et al., 2015, 2016;). The conventional collectors used in the flotation of scheelite ores are generally fatty acids or fatty acid derivatives ( Yongxin & Changgen, 1983; Oliveira & Sampaio, 1988; Sivamohan, 1988; Shi et al., 2014; Bo et al., 2015). It is difficult to separate scheelite especially from calcite with these reagents because the adsorption mechanism of these collectors occurs through chemisorption of the oleate ion onto the mineral surface (Atademir et al., 1979; Changgen and Yongxin, 1983; Hiçyìlmaz et al., 1993; Hu et al., 2011). Therefore, it is almost impossible to separate them by fatty acid flotation without using any selective depressant. Although oleoyl sarcosine was used as a selective collector in the flotation of fluorite and siliceous scheelite ores (Ozcan & Bulutcu, 1993b; Ozcan et al., 1994), this selectivity is not adequate for a low-grade calcitic scheelite ore. Unfortunately, the reagents such as organic colloids (dextrine, starch), quebracho, sodium phosphates, sodium silicate solutions containing polyvalent cations (hydrosols), etc. (Yongxin and Changgen, 1983; Schubert et al., 1990; Shi et al., 2014; Bo et al., 2015) used for calcite depression also depress scheelite to a large extent."

Jan 1, 2016

By O. A. Carson

"IntroductionTHE ZINC-BASE die casting alloys in common usage contain approximately 4 per cent aluminum as the major alloy element. In addition, they contain about 0.05 per cent Mg .and may• have a small amount .of copper. These are usually the only •elements intentionally present.Small amounts of some impurities have been shown to have a deleterious effect on the properties of these alloys and therefore the impurities are kept low by starting with '99.99%' zinc.The reasons for holding the aluminum content at 4 per cent are not clear. Some statements appear in the literature that higher aluminum increases the brittleness, but probably the chief reason was the relative price of zinc and of aluminum when 4% alloys became firmly established. At that time, aluminum was three to four times the price •of zinc on a weight •basis. Recent prices, roughly equivalent per lb., make aluminum considerably cheaper than zinc on a volume basis and suggest that increased aluminum content would result in a decrease in the cost per piece due to the lower density of the alloy.Little information could be found in the literature and, therefore, it was decided to determine some physical properties of the higher aluminum zinc-base alloys made from high-purity zinc."

Jan 1, 1953

The integration of mining and mineral processing technologies into new advanced mining systems is considered to offer several benefits, including selective mining, reduction in waste, increased productivity, flexibility, and improved resource utilization. This paper focuses on underground hardrock mining and the integration of pre-concentration technologies into future mining systems as representing realistic, shorter-term integration options. Control of fragmentation to optimize grinding, pre-concentration of ores, in situ leaching, and modular mining/mineral processing systems are possible with existing technology. Current research is directed toward development of integrated underground systems that minimize surface activity and minimize or eliminate surface waste disposal. Results from a simulation model of an integrated underground pre-concentration system are presented.

Jan 1, 2002

By J. A. Drozdiak

In this paper we examine, through pilot-scale testing, the possibility of operating a circuit comprised of two stages of HPGR comminution, followed by grinding through a horizontal stirred mill. In order to assess whether the novel circuit design could achieve the reduced energy requirements indicated in the literature, two more-established circuits, a cone crusher / ball mill and an HPGR / ball mill, were examined using a combination of testing and flowsheet simulation. The results showed that, based solely on the specific energy requirements for comminution, the HPGR / stirred mill circuit achieved a reduction of 9.2% and 16.7% over the HPGR / ball mill and cone crusher / ball mill circuits, respectively.

Jan 1, 2012

By Y. Lizotte

"This paper examines the application of blasthole sloping to narrow vein mining in Canada, for ore deposits where widths are less than two metres. While the technique has now been utilized for more than ten years, it remains in the experimental stage and on-site testing is necessary for its adoption at new mining operations or in differ¬ent geological settings. It is intrinsically a safer method than other narrow vein methods in current use.The investigation describes the main operating parameters for mines recently surveyed. The criteria for method applicability are defined and the problems encountered are studied. It is concluded that blasthole sloping for narrow vein mining is a viable modern method which promises to gain popularity and that emerging fragmentation technology and blasting research can be used to further increase applicability of the stoping method."

Jan 1, 1991

By T. Adamcewicz

The province's lignite resources lie mainly in the south, extensions of the much larger deposits in Montana and North Dakota. Because of planned additional capacity, conventional steam power generation will probably remain as the dominant resource usage for many decades. Conversion of coal to other energy forms is receiving emphasis and in the future will compete with steam power generation in terms of quantities used.Economic deposits, minable by present-day technology, have been generally defined. Because a large percentage of the total lignite resource is in seams containing multiple partings, future extraction will become much more difficult and capital intensive.Increased public involvement will ensure that the impacts of future coal mining and usage operations are compatible with environmental and social objectives.

Jan 1, 1982

By M. Lindgren

"Hydrometallurgical processing involves process stages, like leaching, that create harsh environment for stainless steels. High acidity, the presence of chlorides and oxidizing ions combined with relatively high temperature create risk for both uniform and localized corrosion. Advanced electrochemical techniques were employed to study uniform and pitting corrosion of two stainless steel grades 316L and 2205. Results obtained with the linear polarization resistance technique combined with the harmonics distortion analysis, electrochemical noise and coupled multielectrode array systems are compared to the results of conventional electrochemical techniques and immersion tests.INTRODUCTIONHydrometallurgical processing has become favoured in metals production in recent years due to energy costs, leaner ore bodies and environmental factors. Because the hydrometallurgical processing route is flexible, various types of secondary raw materials, like flotation tailings, dusts, sludges and slimes can also be treated in addition to conventional mineral concentrates (Sarveswara Rao & Acharya, 2008).Hydrometallurgical processing relies on aqueous chemistry, usually acids, at temperatures around 100°C for the recovery of metals from ores, concentrates, recycled or residual materials. The processing route can typically be divided into three stages: leaching, solution concentration/purification and metal recovery. The processing environment is aggressive, especially in leaching. High acidity, relatively high temperature together with impurities, like chloride ions, place high demands on the corrosion resistance of construction materials. The dominant corrosion mechanism may be uniform corrosion or localized corrosion depending on the process conditions (Ekman & Torsner, 2010). This complicates the prediction of corrosion rates and, consequently, cost effective material selection.Traditional means to evaluate uniform corrosion resistance of stainless steels are immersion tests and the results are published in the form of iso-corrosion diagrams (Outokumpu Stainless, 2010). For the localized corrosion, namely pitting and crevice corrosion, immersion tests can be used but the duration of the test is rather long because an incubation period takes place prior to the occurrence of the actual localized corrosion damage. Electrochemical techniques, traditionally in the form of cyclic polarization scans, have been employed to assess the susceptibility of a material to pitting corrosion (Papavinasam, 2008). They cannot, however, give any indication of the pitting corrosion rate and lack potential for on-line measurements."

Jan 1, 2012