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By William Stewart, John Tinkler, Gary B. Hemphill

Of the 345 km long Taiwan High Speed Rail Project, connecting the cities of Taipeiand Kaohsiung, the 23 km alignment on Contract C230 required the construction of5755 m of shallow mined tunnels ranging from 137 m to 1285 m in length. All nine of these tunnels were mined using NATM methodology. On September 6, 2002, a collapse occurred in Tunnel T08 that affected approximately 50 m of tunnel. There was little warning. However, the crew was evacuated approximately 45 minutes prior to failure and thus, no injuries or loss of equipment. This paper will discuss the mining methods, jet grouting ground support, and the instrumentation selected for the rehabilitation and monitoring of the tunnel.

Jan 1, 2005

By V. Riihimäki, M. Luotamo

The Unit of Toxicological Risk Assessment of the Finnish Institute of Occupational Health (FIOH) is conducting a 'Health Risk Assessment for Metallic Chromium and Trivalent Chromium' under the sponsorship of the International Chromium Development Association (ICDA) and the International Stainless Steel Forum (ISSF). This risk assessment will be conducted in accordance with the current European Union legislation in force (Council Regulation 793/93/EEC, Commission Regulation 1488/94/EEC, Dir. 67/548/EEC), but also to meet the regulatory obligations as set out in the European Commission REACH legislation proposal (Consultation Document, the Registration, Evaluation, Authorisation and Restrictions of CHemicals). Further aims include outlining the criteria for the setting of occupational exposure limits for metallic chromium and trivalent chromium compounds. Human Health Risk Assessment according to the current legislation shall entail hazard identification of the toxic end points (acute toxicity, irritation/corrosivity, sensitisation, repeated dose toxicity, mutagenicity, carcinogenicity, reproductive toxicity) including, as appropriate, dose (concentration) - response assessment, and derivation of the N(L)OAELs (No (Lowest) Observed Adverse Effect Level) and/or DNELs (Derived No Effect Level). Exposure assessments for workers, consumers and humans exposed via the environment take into account all the known intended uses. Risk characterisation will compare the typical and/or reasonable worst case exposure estimates to the N(L)OAELs or DNELs to determine Margins of Safety (MOS) for all human populations by each exposure scenario and type of effect, followed by conclusions about the presence or absence of risk. Although all of the key elements of existing legislation remain in REACH, the principal change is that, the burden of proof will be transferred from the member state authorities to industry. The new proposed format of Chemical Safety Report (CSR) will include Risk Management Measures (RMM) as an essential part of the report in addition to the risk assessment. The RMM plays a role in the evaluation of further testing needs and advocating reasons for possible waiwer of requirements. The research programme started in March 2002 and will be completed within the time frame of two years.

Jan 1, 2004

By Jean J. Tancous

Chromium recovery from wet-blue offal trimmings and shavings can be done with substantial chemical cost gains by incineration at 600° C for 5 hr. Pretreating the offal with 0.5 M Na2C03 and air-drying prior to incineration produce Cr04 .By simply incinerating the offal, without pretreatment, an ash containing water insoluble Cr203 was produced. The Cr203 in the ash was purified by leaching with water. Chromium and crude protein were efficiently extracted from offal using 5 pct Na103, 5 pct H2S04, and 3 pct NaCl at 40° C. This procedure was effective but expensive. Satisfactory leather as to odor, appearance and shrinkage temperature was made from chromium recovered from wet-blue offal by incineration and by extraction. Chromium conservation is possible by recycling chromium liquors and by precipitating chromium from spent tanning liquors prior to combining these liquors with other tannery wastes. Combining chromium liquors with other wastes introduces contaminants that make chromium recovery and reuse difficult. Leaching sludges with H2SO4 produced marginal chemical cost gains. Leather tanned with these solutions had satisfactory shrinkage temperature but the sludge odors and iron contamination were objectionable.

Jan 1, 1979

By Brunno Spinelli Pimentel

Ambientes contendo H2S e CO2 impõem condições severas a componentes fabricados em aços, já que estes podem sofrer corrosão com perda de propriedades mecânicas e falha das instalações. Uma preocupação é a quantificação dos fenômenos envolvendo difusão do hidrogênio atômico, o qual (seja pelo gás H2 em interfaces ou pela interação com ligações atômicas ou discordâncias) pode causar redução nas energias superficiais de fraturamento prejudicando ductilidade e tenacidade. Neste cenário, este trabalho investiga a fragilização por hidrogênio em um aço microligado API 5L X65 sour obtido de um tubo de diâmetro externo 32” e espessura de parede 20,6 mm fabricado pelo processo UOE. Amostras longitudinais e transversais de tração (ASTM E8/E8M) foram extraídas e imersas em solução saturada com H2S. O eletrólito empregado foi a solução A (ácido acético contendo cloreto de sódio) da norma NACE TM0284-2011, fazendo-se purga com N2 e injeções de H2S. Os tempos de imersão foram de 0, 96 e 360 horas, sendo os ensaios de tração realizados após doze dias do término da imersão. Os resultados não revelaram efeito estatisticamente relevante na resistência mecânica, na evolução tensão-deformação e tampouco no módulo de tenacidade. Entretanto, foi observado maior espalhamento dos resultados advindos de amostras submetidas a H2S. Esse comportamento sugere que o hidrogênio influenciou no micromecanismo local de fraturamento, mas com inexpressivo comprometimento das propriedades monotônicas macroscópicas. Tal desempenho pode ser fruto da microestrutura com grãos refinados e do baixo nível de inclusões encontrado, indicando poucos e uniformes sítios de ancoramento de hidrogênio irreversível.

Aug 8, 2018

By A. Moss

The Palabora Mining Company has successfully extended the life of its operation by developing a 30 000 tpd block cave underground mine below the now closed open pit. The process of transitioning from surface to underground mining has been technically, operationally and managerially challenging. This has been due to a number of factors, in particular, the development of a block cave in a very competent rock mass. The competence of the rock mass is clearly demonstrated in the open pit that preceded the block cave, one of the steepest deep open pit excavations in the world. With cave breakthrough, however, the pit was ?instantaneously? deepened by 400 m causing a major failure of the north-west wall involving close to 100 Mt of waste material.

Jan 1, 2006

By Maryam Sadeghi, Jonathan Roy, Claude Bazin

"The operation of mineral processing equipments is intimately related to the mineral composition of the ore. However unit performances are usually characterized in terms of metal contents or recoveries as this data is easier to obtain than the mineral contents. This paper describes a method that combines the operations of material balancing and estimation of the mineral contents of the ore. The estimated mineral contents can be used for process analysis and diagnosis of operating problems.IntroductionThe ore that is feeding a concentrator is made of minerals that condition the energy requirements for the ore comminution and the performances of the subsequent separation circuit. Indeed a change in the mineral composition of the ore may lead to lower grinding mill throughput as well as lower recovery or grade of the economical products. Despite this relationship is recognized the mineral composition of the ore is seldom measured or estimated to provide regular information for the diagnosis of operating problems. Some methods such as the QEM-SCAN (Whiten, 2008; Lamberg and Vianna, 2006) are available to measure the concentration of the minerals in ore samples but the method is time demanding and plant operators usually base their evaluation of the plant performances on chemical assays of metals or elements since this data is easier to obtain from ore samples.Usually samples of the streams of mineral processing plants are collected on a daily basis to be assayed for strategic elements. The obtained concentrations are balanced to produce coherent data with the material conservation constraint and then used to characterize the day to day operation of the plant in terms of recovery of valuable metals and grades of the marketable concentrates. The behavior of contaminant elements can also be monitored from this data allowing the operators to explain for instance a lower zinc concentrate grade by a more important contamination of iron. However such diagnosis is only partial as the contaminant element can be transported by different minerals. Indeed the iron contamination of a zinc sulfide concentrate may be caused by an inadequate depression of pyrite or due to another iron carrying mineral. A possible way to answer the question is to determine the concentrations of the various minerals in the ore and produced sealable concentrates. Since measuring the mineral contents of the ore could be a demanding task one should consider to estimate this data from the daily chemical assays of the sample collected on the main streams of the circuit. Some authors have already investigated the problem. Whiten(2008) described a method to estimate the mineral contents of an ore sample. Lamberg and Vianna(2006) proposed a method to do a sequential mineral reconstruction followed by a material balance. Few of these methods account for the mass conservation of the reconstructed mineral contents."

Jan 1, 2016

By Mike Samuels, John Starkey

"This paper examines test results and grinding mill design for the recent Fortune Minerals’ NICO Project, located in the Northwest Territories. SAG milling and rod milling options are compared. Rod milling is clearly shown to be the best option because of the ore’s extreme resistance to breakage in a SAG mill environment.Surprisingly, the Bond Ball Mill Wi was 13 kWh/t for this ore. The Bond Rod Mill Wi was 20 kWh/t, whereas the SAG pinion energy to grind the ore to T80 1.7 mm was 30 kWh/t. The existence of ore with this ratio of SAG hardness to Bond BM Wi has not been previously observed. If not considered, this critical relationship may adversely impact the accuracy of mill design. This paper substantiates the significance of these findings to achieve successful grinding design on ore that is macro-competent during primary size reduction, but relatively normal during secondary grinding.INTRODUCTIONThe NICO Cobalt-Gold-Bismuth-Copper deposit is located 160 km northwest of the City of Yellowknife, Northwest Territories. It is the largest IOCG-type deposit (aka Olympic Dam-type) currently recognized in Canada with Mineral Reserves of 21.8 million tonnes contained within a larger 57 million tonne, lower-grade Mineral Resource. The project, owned 100% by Fortune Minerals Limited, has been assessed in a positive definitive feasibility study, subject to underground test mining and pilot plant testing, and is now in the permitting stage to develop a combined open pit and underground mine and process plant. An updated process flow sheet incorporates conventional crushing, grinding and bulk flotation, followed by filtration for shipment of a concentrate to a purpose-built refinery proposed to be built near Saskatoon, Saskatchewan. At the refinery, separate bismuth and cobalt concentrates will be produced following regrinding. The hydrometallurgical process methods include: pressure acid leach, precipitation, ion exchange, and electro-winning for recovery of cobalt as 99.8% cathode; solvent extraction and electro-winning of by-product copper cathode; ferric chloride leach and electro-winning for recovery of bismuth as 99.5% cathode; and cyanidation of the leach residues for recovery of gold as doré."

Jan 1, 2010

By M Vendrup, T C. Christensen, C Dube

The adsorptive and granulate forming MetClean™ process has been used at many locations in Northern Sweden, Norway, Denmark, France, Spain, Mongolia, Japan and Australia. It has been pilot tested and used in full scale treatment plants to remove metals from:mine watersleachate from solid waste in incineration flue gasleachate from fly ash damsleachate from landfill and waste ponds.The following paper provides details of pilot and plants tests on the effectiveness of MetClean™ in removing arsenic, antimony, barium, cadmium, copper, molybdenum, nickel, radium, uranium, vanadium and zinc. Results show that MetClean™ may reduce the concentration of these metals in treated effluent water to the one part per billion (ppb) range.The paper also finds that, for specific metals, the optimal adsorption condition depends on the:pH levelmolar relation between the specific targeted metal and the addition of iron (II) or manganese (II)type of oxidation agentssalinity levelpresence of other metals.The most effective pH level varies according to the targeted metal but falls within the pH 5 to pH 11 range. A compromise pH level may be set when more than one metal is targeted for removal at the same time and through only one process step. The removal efficiency of one or both metals may be affected by operating at a compromise rather than optimum pH level.The MetClean process generates non-hazardous solid waste. Waste can then be disposed of more easily than brine or sludge.CITATION:Christensen, T C, Vendrup, M and Dube, C, 2015. Pilot tests for heavy metals removal in mine water, in Proceedings MetPlant 2015, pp 404–415 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By P. Creevy, P. F. Mousset-Jones, G. Danko, A. D. S. Gillies

The surface heat transfer coefficient is measure of the rate of heat transfer from exposed rock surfaces to the ventilating air. Knowledge of its value is of particular importance to accurately simulate the early stages of rock cooling after the opening of an excavation. A number of theoretical formulae for the calculation of the coefficient are available for use in mine climate simulation. However, direct determination by in situ measurement is preferred. Instrumentation, which has been developed for in situ mine measurement, and experimental procedures involving measurement at varying air velocities, are described. In a major study covering four Australian underground mines, the system has been used to determine surface heat transfer coefficients. A direct relationship was clearly established between the measured surface heat transfer coefficient and air velocity. Comparison is made between experimental results and those previously measured or calculated by others. The relationship established can be described by an equation and holds for air velocities above 0.4 mls. The derived relationship was con- firmed at all mines tested and is independent of geology and tunnel dimensions found in modern mines.

Jan 1, 1991

By Patrick Bermingham

This report presents the results of six STATNAMIC loading tests that were carried out on four different pile types at the CALTRANS 280 Test Site (Bridge No. 34-46) in conjunction with the Tension Pile Test Program. The STATNAMIC testing was performed by Berminghammer Corporation at the request of the California Department of Transportation, Office of Geotechnical Engineering. Others performed the static tension (uplift) and compression loading tests which werecarried out on the piles tested using the STATNAMIC method. A summary of the STATNAMIC test results is presented and discussed, and the appropriate results are compared with the static test results

Jan 1, 1993

By G C. Bolton

Experiments were conducted to access the feasibility of removing zinc from lead slag by sulfation or chlorination or both. Gaseous sulfation with sulfur dioxide and oxygen released only 50 per cent of zinc even under the most severe conditions. Sulfation with concentrated sulfuric acid by a fast-leach process released 95 per cent of zinc while pug-roasting released a maximum of 78 per cent of zinc. Chloridization with NaCl in the presence of sulfating gas released 50 per cent of zinc, while direct chlorination with chlorine gas and oxygen released 85 per cent of zinc and 100 per cent of lead in a chloride condensate containing little impurities.

Jan 1, 1980

By Walter E. Duncan

The ores treated at the concentrating plant of the Mahoning Mining Co. at Rosiclare, III., come largely from the blanket replacement deposits of the northeastern part of Hardin County, Illinois, and consist of complex mixtures of galena, sphalerite and fluorspar in a gangue of quartz, limestone and sandstone. The several minerals are so intimately inter-grown that they are not liberated at the sizes usually treated by gravity concentration in the usual fluorspar plant. For this reason, an all-flotation method of concentration was developed in cooperation with the station of the U. S. Bureau of Mines at Rolla, Mo.1 This flotation separation made possible the commercial production of four concentrates: (I) lead, (2) zinc, (3) acid-grade fluorspar and (4) metallurgical-grade fluorspar.2,3 Although fluorspar had been floated in Canada in 1921 and a plant at Rosiclare had been floating fluorspar since March 1929, fluorspar flotation was given considerable impetus by the Mahoning developments, since some features of the separation were quickly adopted by other fluorspar companies. The Bureau of Mines6 reports that in the 10 years preceding 1938 only 50,552 tons of fluorspar flotation concentrates were produced in the United States. The rise from this almost nominal figure to 153,750 tons (largely acid grade) in one year (1944)6 is indicative of the activity in fluorspar flotation occasioned by the war. The industry thus proved to be in a position to expand and keep up reasonably well with the requirements imposed upon it by such developments as occurred in high octane aviation gasoline alkylation, in the use of Freon as a refrigerant and as carrier in the Aerosol "bug bomb," and in the atomic bomb project as well as in the expansion of other activities requiring hydrofluoric acid; for example, the aluminum industry. Despite the fact that the greater portion of acid-grade fluorspar produced in the last few years went directly into war uses, the future of the acid-grade field still appears bright. As a result of the activity in fluorine chemistry during the war, it seems likely that in the relatively near future almost every phase of human endeavor will find some fluorine compound involved. The other three concentrates produced deserve some attention in these introductory remarks. The lead concentrates first produced contained both zinc and fluorspar but these did not interfere with their marketing. As will be pointed out later, the quality has steadily improved until today it is a relatively high-grade product. Although some zinc smelters accept concentrates containing limited quantities of fluorspar, it is a very objectionable impurity. Since flotation methods fail in the complete removal of the fluorspar, chemical methods were developed for

Jan 1, 1947

By Walter E. Duncan

The ores treated at the concentrating plant of the Mahoning Mining Co. at Rosiclare, III., come largely from the blanket replacement deposits of the northeastern part of Hardin County, Illinois, and consist of complex mixtures of galena, sphalerite and fluorspar in a gangue of quartz, limestone and sandstone. The several minerals are so intimately inter-grown that they are not liberated at the sizes usually treated by gravity concentration in the usual fluorspar plant. For this reason, an all-flotation method of concentration was developed in cooperation with the station of the U. S. Bureau of Mines at Rolla, Mo.1 This flotation separation made possible the commercial production of four concentrates: (I) lead, (2) zinc, (3) acid-grade fluorspar and (4) metallurgical-grade fluorspar.2,3 Although fluorspar had been floated in Canada in 1921 and a plant at Rosiclare had been floating fluorspar since March 1929, fluorspar flotation was given considerable impetus by the Mahoning developments, since some features of the separation were quickly adopted by other fluorspar companies. The Bureau of Mines6 reports that in the 10 years preceding 1938 only 50,552 tons of fluorspar flotation concentrates were produced in the United States. The rise from this almost nominal figure to 153,750 tons (largely acid grade) in one year (1944)6 is indicative of the activity in fluorspar flotation occasioned by the war. The industry thus proved to be in a position to expand and keep up reasonably well with the requirements imposed upon it by such developments as occurred in high octane aviation gasoline alkylation, in the use of Freon as a refrigerant and as carrier in the Aerosol "bug bomb," and in the atomic bomb project as well as in the expansion of other activities requiring hydrofluoric acid; for example, the aluminum industry. Despite the fact that the greater portion of acid-grade fluorspar produced in the last few years went directly into war uses, the future of the acid-grade field still appears bright. As a result of the activity in fluorine chemistry during the war, it seems likely that in the relatively near future almost every phase of human endeavor will find some fluorine compound involved. The other three concentrates produced deserve some attention in these introductory remarks. The lead concentrates first produced contained both zinc and fluorspar but these did not interfere with their marketing. As will be pointed out later, the quality has steadily improved until today it is a relatively high-grade product. Although some zinc smelters accept concentrates containing limited quantities of fluorspar, it is a very objectionable impurity. Since flotation methods fail in the complete removal of the fluorspar, chemical methods were developed for

Jan 1, 1947

ThePike River coal field is located between 700 and 1000 m above sea level on the West Coast of the South Island. The area contains a resource of some 60 million tonnes of coal in a single coal seam and is part of the Paparoa mountain range that receives between 6.0 and 6.5 m of rainfall per annum. The area has been isolated and has received no on the coal plateau but has been extensively logged in the lower 3.5 km of Pike Stream. The PRCC development proposal recognises this and calls for an environmentally benign development that includes underground development of this resource. The coalfield abuts and is partly overlain by the Paparoa National Park. The underground development will enable a number of environmental goals to be readily achieved: it will be out of sight of the public,it will not impact the national park,noise will be mostly absent,there will be absolute minimal disturbance to the land surface,coal will be transported from the mine to a dewatering complex on PRCC land in a slurry pipeline thus obviating the need for trucks and noise in Pike Stream valley,all water draining from the mine will be collected, treated if required to consent standards and discharged from a single point,the road into the area will allow for an effective predator control programme to be undertaken enhancing native bird life,an environment suitable for the reintroduction of Whio (Blue Duck) will be created, andthe net effect of the mine development on the environment will be positive.

Jan 1, 2003

Prof. A. Ledebur, Freiberg, Saxony :* Mr. Sauveur has presented and enriched with original observations a valuable summary of the theories advanced hitherto concerning the hardening of steel; but in one particular, it seems to me, his statements call for correction. He says:

Jan 1, 1898

By F. S. Wartman

The presence of magnetite, either dissolved or suspended as solid crystals, in slags from the copper reverberatory furnace is a frequently mentioned cause of an abnormally high copper content in those slags. The presence of this oxide in the slag is to be expected, since it is present in appreciable amounts in both converter slag and roaster calcine which comprise a considerable proportion of the furnace feed. Magnetite is also a product of some of the furnace reactions. These abnormal losses result in several ways. Magnetite is supposed to favor the formation and retention of copper ferrite, in the slag. Crystals of solid magnetite suspended in the slag are objectionable-because they make the slag less fluid and often entrap globules of matte. Frequently these crystals settle into a layer at the slab-matte interface which may have such mechanical strength as to create a false bottom and interfere with furnace operation by preventing separation of matte from slag. Magnetite may, by crystallizing on the furnace bottom, build the bottom to such a level that the furnace can no longer be operated.

Jan 1, 1928

By P. Burke, V. Vuaroqueaux, A. Doyle, C. Petit, Kipouros. G. J.

Magnesium and its alloys are attractive for use in automotive and aerospace applications because of their low density and good mechanical properties. However, difficulty in forming magnesium and the limited number of available commercial alloys limit their use. The present work reviews the efforts to improve the attractiveness of magnesium through non-traditional processing, and presents results of current work on producing magnesium alloys via powder metallurgy (P/M). P/M can be used to alleviate the formability problem through near-net-shape processing, and also allows unique chemical compositions that can lead to new alloys with novel properties. The surface layer formed on the Mg powders during processing acts as a barrier to diffusion and sintering is problematic. The layer contains oxides, hydroxides and carbonates of magnesium, formed by reactions with the atmosphere. There are several means to possibly overcome this barrier. Alloying additions have been identified that may promote surface layer disruption during sintering. Processing variables such as sintering atmosphere may reduce the layer or allow the formation of less detrimental compounds. Post-sintering processes such as hot working may disrupt the layer and improve density. The experimental effect of all these processing parameters is presented in this paper.

Jan 1, 2010

By K. Nasrallah

"The Dumont deposit is a large (1,179 Mt proven and probable reserve) low grade (0.27% nickel), nickel sulphide project located in the Abitibi region 25km west of Amos, Quebec. Royal Nickel Corporation acquired the project in 2007 and has since taken the project from a scoping study in 2010 through to completing the feasibility study in July 2013.The Dumont deposit in a nickel deposit with the recoverable nickel contained in three minerals; pentlandite, haezlewoodite and awaruite. The minerals are recovered by a combination of flotation and magnetic separation. Over the course of the studies many flowsheet design decisions and changes were made. This paper outlines an overview of the project, flowsheet design including the comminution circuit, desliming and awaruite recovery. The overall resulting flowsheet that was used for the feasibility study is then presented along with the confirmatory locked cycle testing that showed the feasibility design basis was able to produce the predicted concentrate grade and recovery.IntroductionRoyal Nickel Corporation (RNC) is a mineral resource company headquartered in Toronto, Canada, primarily focused on the exploration, evaluation, development and acquisition of base metal and platinum group metal properties. RNC's principal asset is the Dumont Nickel project (Dumont project) located in the established Abitibi mining camp, 25 km northwest of Amos, Quebec. RNC acquired a 100% interest in the Dumont property in 2007. The mineral claims covering the Dumont deposit are currently held 98% by RNC and 2% by Ressources Québec.The Dumont project is located in the province of Quebec in the municipalities of Launay and Trécesson approximately 25 km by road northwest of the city of Amos, 60 km northeast of the industrial and mining city of Rouyn-Noranda and 70 km northwest of the city of Val d’Or."

Jan 1, 2016

By P M. Ashley, M T. Costelloe

The Mary Kathleen tailings storage facility (TSF) contains 7.1 Mt of uranium mill tailings. This waste repository was rehabilitated in the mid-1980s using a multibarrier dry cover. At the time of mine closure, it was predicted that acid mine drainage (AMD) generation would not eventuate and that uranium, heavy metals and radionuclides would be adsorbed within the tailings and not seep from the TSF into the environment. This study reports on the environmental status of the TSF. Gamma-ray measurements indicate an intact dry cover of the waste repository. However, seepage (~0.5 L s-1) of acid (pH 5.71), saline (0.31 per cent), high conductivity (8.8 mS cm-1), slightly oxygenated (DO 2.6 mg L-1), radioactive waters occurs from the toe of the tailings dam into the former evaporation ponds and local drainage system. Seepage waters are calcium-magnesium-sulfate rich with elevated Fe, Mn, Ni, U and Zn values. Oxygenation of tailings seepages causes the precipitation of Fe and coprecipitation and adsorption of other metals (Pb, U, Y), metalloids (As), rare earth elements (Ce, La) and radionuclides (U-235, U-238, Th-227). In contrast, Ba, Ni, Sr, Mn, P, S, Ca, Mg, Na and K as well as Ra nuclides (Ra-226 and Ra-228) remain in solution until pH neutralisation and evaporation lead to their precipitation in efflorescences and sulfate-rich evaporative sediments further downstream. Dry capping of Mary Kathleen uranium mill tailings has resulted in physical containment of the wastes. The dry cover shows no signs of erosion and radiation levels are within acceptable limits. However, the flow rate of surface seepage from the TSF occurs at a much higher rate than predicted. Also, the neutralising potential and adsorption capacity of the tailings and underlying aquifer were overestimated at the time of mine closure. AMD has developed mobilising metals, metalloids, rare earth elements, alkalis, radionuclides and sulfate from the waste repository into surface water seepages.

Jan 1, 2003

By Swapan Ghosh, Amitava Sengupta, Proloy Das

Ferro-alloys are very important ingredients used for making of quality steel with desired composition. In view of high demand in various types of ferro-alloys, it has become necessary to produce the same efficiently, safely and cost-effectively with consistent quality maintaining the anti-pollution norms. To achieve this goal, it is necessary to adopt latest process/equipment with the state-of-the-art instrumentation and automation system. A Programmable Logic Controller (PLC) based automation system with suitable Human Machine Interface(HMI) terminals along with intelligent field mounted sensing/control devices allows to monitor and control the complete plant effectively with optimum deployment of man-power. In association with this, use of process optimization controllers enables to achieve specialised functionalities of the submerged arc furnaces like material management, lining management, electrode management, power management, overall production management etc.

Jan 1, 2007