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Pergamon Minerals Engineering, Vol. 9, NO. 9, pp. 907-921, 1996Copyright 1996 Elsevier Science LtdPrinted in Great Britain. All rights re,servedPl h S08 92- 687 5(9 6)0 008 3-- 0 0892-6875/96 $15.00+0.00

I M P R O V I N G E N V I R O N M E N T A L P E R F O R M A N C E T H R O U G HI N N O V A T I O N : R E C E N T T R E N D S I N T H E M I N I N G I N D U S T R Y

A . W A R H U R S T a n d G . B R I D G EUnive rsity of Bath, International Centre fo r the Environm ent,School of Management, Bath BA2 7AY, UK

(Received 24 Apr i l 1996; accepted 1 June 1996)

A B S T R A C TI nnov a t i on i n m i ne r a l p r oc e s s i ng t e c hno l ogy c an e na b l e m i n i ng c om pan i e s t o c om b i nega i n s i n p r oduc t i v i t y w i t h i m pr ov e m e n t s i n e nv ir onm e n t a l m anage m e n t . A l t houg h t hem i n i ng i ndus t ry has a r e pu t a ti on f o r t e c hno l og ic a l c ons er va ti sm , t h i s pa pe r a r gue s t ha tt he de v e l opm e n t , ac qu i s i ti on and a s s i m i la t i on o f ne w t e c hno l og i e s m ay b e an i nc r e as ing l yi m por t an t de t e r m i nan t o f a c om p any ' s c om pe t it iv e pos i t i on i n t he c on t e x t o f g r ow i ngm ar k e t and r e gu l a to r y p r es s ur e s. Spe ci fi c e x am p l e s o f i nnov a t iv e p r oc e s s and r e m e d i a t iontechnolo gies are rev iewed, an d the i r abi l i t y to improve compet it iveness an d sus ta in bes t-p r ac t i c e e nv i r onm e n t a l m anage m e n t i s l i nk ed t o the c apac i t y o f t he c om pany t o m ana get e c hno l og i c a l and o r gan i s a t i ona l change. C opy r i gh t 1996 E l s e v i e r Sc ie nc e L t d

K e y w o r d sEnvironm ental; mineral economics; mining; hydrom etallurgy; pyrom etallurgy

I N T R O D U C T I O NTh e international lnining indus try has a reputation for technological conservatism. Th e U.S . O ffice ofTec hnolog y Assessment, for example, describes this as a " tendenc y to repair , rebuild, and retrofit, ratherthan repla ce.. .equip me nt" [1] . This reputation, how ever, is only partly justified. To the e xtent that i t isbased on the radk',al (and therefore most visible) technological breakthroughs, the reputation is valid.Radical technical change involving a signif icant departure from past practice is relatively rare in theindustry, ref lecting high capital costs, long lead t imes of project developmen t, and the highrisks invo lved in comm itting capital and expertise to unprov en technology. Technolog y developm ent isinherently r isky and corporate aversion to r isk in the mining sector is particular ly acute due to the alreadyconsiderable polit ical r isks associated with the developme nt and operation of m ines in overseas locationsand the commerci;d uncertainties stemming from the vagaries of market demand. The reputation forconservatism is unjustif ied, however, if one considers the role of incremental technological andorganisational improvem ents in the development of the industry during the twentieth century. Improvem entsin process co ntrol and optimisation, or the application of existing technologies at increasing scales ofoperation to ca pture greater eff iciences, have been fundamental to the competit iveness of m ajor m ineralproducers. By reducing costs per unit of output, such improvements have enabled companies to circumv entthe dim inishing economic returns associated with developing an ore bo dy of f ixed geological properties andspatial exten t under conditions of a static techn ology.

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908 A. Warhurst and G. BridgeT H E I M P E R A T I V E T O I N N O V A T E IN M I N I N G

Innovation is central to sustaining th e competitiveness of mining oper ations since by reducing pro duc tioncosts , new proc ess techniques enable the profitable extraction and processing of lower grade and m orecom plex ores. It is argu ably the incremental innovations associated with the increase in capacity and scaleof mineral pro cessing techniques, such as grinding, column flotat ion, and earth moving equipm ent ( i tselfdepende nt on advances in rubb er technolog y for tyres and conve yor bel ts) that have ena bled the cont inuedcom peti t iveness of mining regions which have only relatively low-grade deposi ts remaining (e.g. co pperin the U.S .) . T he incremental nature of many o f these innovations can be i llustrated by reference to theincreasing scale of long-wall m ining techniques [2]. The ability of long-wall m iners to wo rk a face300-1000 metres long is dependent , in part , on small yet s ignificant improvements to the s t rength ofcarbide s teels which hav e increased the durabi l i ty of bucke t whee l excavators and the ab i l i ty of the long-wall machine to penetrate harder rock.

R E N E W E D I N C E N T I V E S T O I N N O V A T E

The com peti t ive imperat ive for mining companies to develop , acquire, and assimilate new techno logy hasbeen re-invigo rated by mark et and regulatory pressures over the las t decade. Intensif ied com peti t ion inminerals markets and the "environmental imperat ive" have increased the incentive fo r mining comp aniesto invest in the innovat ion and assimilat ion of new technologies in order to remain co mp eti t ive. Innovat ionis increasingly a key determinant of competi t iveness for mining companies . The CE O o f Kalgo ol ieCon sol idated Gold Mines, Austral ia recent ly described the s i tuation as one of " innovate or perish". W ithoutinnovat ion and techn ology developm ent , A ustral ia w ould not recover i ts posi t ion as a low- cost producerin an increasingly com petitive market [3].Compet i t ive Market PressuresM ost minerals are t raded as hom ogene ous, fungible comm odit ies . M ineral com mod it ies provid e l i tt le scopefor produ ct different iat ion be tween individual producers and, assuming a s tandardised produ ct qual i ty ,competi t ion is based predominant ly on cost . The commodity market therefore provides a considerableincent ive to produce at the lowest cost , part icularly s ince marginal high-cost producers w il l be pushe d outduring cycl ical downturn s in demand. Ov er the las t two decades, com peti t ion in man y minerals marketshas increased, rendering cost-re duc tion throug h technological and organisational chan ge increasinglyimportant to corporate s t rategy. In the 1950s and 1960s s t rong growth in many regional markets and anol igopol is t ic industry s t ructure for key minerals provide d relat ively buoyant market condi t ions with l imitedpressure on price. In the U.S . coppe r industry, for example, ol igopol is t ic control over market supply anda relat ively s t rong dem and in the domest ic market reduced com peti t ive pressures in the industry, postponingthe need to cut produ ction costs and diminishing the incentive for technological change. Since the late1970s, how eve r, many m ineral markets have und ergone a transi tion towards increased com peti t ion due toa num ber o f factors . These include: an increase in new market entrants as a consequence of national isationand expropriat ion in the early 1970s and economic growth outs ide core economies during the 1980s; awo rld-w ide recession leading to a protracted period of exce ~ supply for many metals and industrialminerals; the decline of self-contained regional m arkets and the em ergen ce o f globa l ma rket for mineralsassociated with industrial grow th outs ide of t radi tional market areas o f OE CD ; and comp eti t ion in end-usemarkets fol lowing the developm ent of al ternat ive materials able to perfo rm similar funct ions, for exam plethe increasing importance of plastic rather than copper in the domest ic piping market [4].A 'm easure ' of the increased comp eti t ion in many mineral markets is the shift from regional marketsdominated by p roducer p r i c ing to a g lobal market based on LME/COMEX exchange p r ices . Producerpricing in copp er in the U.S , for example, col lapsed after Kennecott and Anacond a mov ed to exchangeprices after 1978, and nickel , aluminium, and other base metal t rading w ere introduced to the LM E duringthe late 1980s. In the U. S. cop per market, for example, com petition increased w hen the nationalisation ofmining assets in Lat in Am erica in the early 1970s eroded the U.S . copp er ol igopoly by underm ining theabi l i ty of U.S . prod ucers to control the f low of coppe r onto U.S. m arkets . The loss of control ove r the

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Improving environmental performance hrough innovation 909supply of copper to the m arket produce d a st ructural, rather than pu rely cycl ical surplus, driving dow n andmaintaining prices at low levels for much o f the 1980s, and exposing the posi t ion of the U .S. as a high costp roducer . High cos t s and cons i s ten tly low pr ices fo rced U.S. p roducers to f ind ways to reduce p roduc t ioncosts. Significantly th ese included innov ation and acquisition of new prod uctio n tech nolog ies, includinginvestment in econom ies of scale, micro-electronics and process control technology, and proce ssimprovements enabl ing the effect ive coupl ing of solvent extract ion and electrowinning to produce copperfrom low grade oxide and sulphide ores .New Market Opportunit iesAlthough the "e nvironm ental imperat ive" is most often regarded as an external pressure to whichcompanies must re,act, there is em erging e viden ce (particularly in the manufacturing sector) that som ecom panies regard l~e environmen t as a new strategic arena and are taking a proact ive s tance tow ards theenvironm ent to capture a comp eti t ive advantage. There is l it t le evidence as yet (with the possible except ionof aluminium) that non-ferrous metal produce rs are seeking com peti t ive advantage through the market ingof "green" metal products , but some mineral markets are nonetheless very sensi t ive to the qual i ty andrel iable del iver y o f products . To the extent that at t ributes of qual i ty , rel iabi l i ty , and env ironmentalmanagem ent are all depe nden t on the technological, organisational and managerial capa city of com pan ies,there is a correlat ion betw een compe ti t iveness in the marke t and environmental perform ance [5]. Th ere is ,in add ition, a gro win g ma rket for environmental technologies,i services and expertise. The develo pm ent oftechnolog ies and managerial capaci ty in the area of environmental performa nce ca n represent a potent ialnew profi t centre f i~r som e com panies . Mt. Isa Mines, for example, has develope d a successful technologymarket ing g roup which has l i censed a number o f p roduct s inc lud ing ISASM ELT, the Jam eson Cel l and theISA PR OC ES S, a coppe r refining techn ology. Since i ts introduct ion to commerical operat ions in 1990 ove r120 Jam eson C el ls have been dep loyed in a variety of appl ications (see below ), and by 1994 the ISAPR OC ESS had been l icensed to 34 operators representing 20 % of global product ion [38]. T he developm entof f lash convert ing b y Kennec ot t and Outokum pu (see below) has sparked interest in possib le licensingarrangements . Tech nology market ing provides an opportuni ty to recoup R & D costs , al though i t is unl ikelythat technolog y l icensing wil l beco m e a new profi t centre for Kennecott . Alcan has seized on theenvironm ent as a ,~ource of comp eti t ive advantage and is involved in developing innov at ive techno logiesfor industry which wo uld improve the market for recycl ing aiuminium. These include proprietary s t ructuresfor car bodies and an innova t ive bonding system for their at tachment, contribut ing to the environmen talefficiency o f the m otor car through being both l ightweight : ( thus reducing fuel consump tion) and fu l lyrecyclable [6].Techn ological de velopm ent and managerial capaci ty in the areas of qual i ty and environmental perform anceadd value to the compa ny ei ther direct ly ( through patent ing and t rade) or indirectly as part of a com pan y'sresear ch reputatioi~ and international profile. Althou gh intangible, this reputa tion can be a significant fa ctorin determining a company's s tock market value and in obtaining access and credi t in emerging markets .Prov iders o f credi t and insurance arc increasingly aware that poo r environmental perform ance can delaya pro ject significantly and increase exp osure to liabilities. Insurance com panies offe ring political riskinsurance to Austral ian m ining companies , for examp le, hav e s tarted to insis t on annual re view s ofenvironm ental s tandards in the compa nies ' international operat ions [39]. A recent i l lustration of theheightened sensi t ivi ty among financial inst i tut iom wa s provided by the decis ion of the Ove rseas PrivateInvestmen t Corpo:rat ion to withdraw $100 mil l ion worth o f r isk insurance from the Grasberg m ine in Ir ianJaya, ostensibly on the ground s of ecological dam age to forests and river systems [7]. No t only is a goodenviro nm ental re~ord increasingly important in securing financial backing, it m ay also be a facto r in gainingaccess to newly-l iberal ised investment regimes. Increased scrut iny of mining projects from investm ent ,cred it, and insurance co mp anies, the trend tow ards harmonisation of national environmental standards, andthe emergen ce of voluntary s tandards and codes of condu ct at the global level (e.g . ISO 14000, Berl inGuidel ines) are com bining to mak e clean process and best-pract ice s tandards the s ine qua non of marketaccess and project approval . Dem onstrat ion of technological and managerial s t rategies for environm entalbest-pract ice is inrreasingly required b y banks and financial insti tut ions which finance investment pro jectsin the develop ing world, such as the International Finance C orporat ion o f the Wo rld Bank and the JapaneseOverseas E conomic Co-opera t ion fund . W hi le these agencies may pro v ide on ly a small p ropor t ion o f to ta l

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910 A. Warhurst and G. Bridgeproject funding, their approval can be key to leveraging further funds.R e g u l a t o r y P r e s s u re s a n d t h e ' V o i c e o f S o c i e t y 'The rapid increase in environmental legislation over the last 25 years has provided an additional incentiveto innovate in order to stay in business. In response to a raft of regulatory initiatives and elevated levelsof public and commercial concern about the impacts and risk associated with poor environmentalperformance in both industrialised and developing countries, dynamic companies have sought ways toreduce pollution while at the same time remaining competitive. Unlike manufacturing or the electricitygenerating industries, the option of changing raw material feed stocks as a means of reducing pollution isnot so readily available to mining companies (although planning mine development to avoid high sulphideor other problematic ores has been suggested as a way of reducing the potential for pollution duringprocessing: for example, the sourcing of "clean" low-iron zinc sulphide deposits from the Century Minein northern Queensland as feed for Pasminco's Budel zinc smelter in the Netherlands will enable it to meetfuture Dutch regulations on jarosite disposal). The limited scope for changing feed stocks, however meansthat innovation in beneficiation and processing is the primary means by which the environmental impactsof production can be reduced [8].For some companies, regulation has provided the incentive to invest in new processes which are able tolower production costs overall. Faced with increasing controls and penalties on account of the toxic dustcontent of its processing plants, a Brazilian gold company designed and introduced specialised dustprecipitators. As a consequence, not only were dust levels reduced but the extra gold values collected inthe dust more than paid for the cost of buying and installing the new equipment. The rising costs of landdisposal (as a result of increasingly stringent land use controls) for moulding sand at a foundry inPennsylvania, U.S. led the company to invest in a sand reclamation programme as part of a comprehensivewaste minimisation scheme which netted the company $2.4 million per year in savings [9]. In response toa condition of permitting, the Coeur d'Alene mining company developed a cyanide recovery technology(Cyanisorb) to recover cyanide from the tailings stream of its gold operations rather than from decant waterin the tailings pond. As a proprietary technique, Cyanisorb has become a marketable product for thecompany. The threat o f a substantial fine in anticipation of acid mine drainage from low-grade waste-dumpsat Exxon's Los Bronces mine in Chile, led the company to seek alternative solutions. The fine providedan economic justification for the development of a bioleaching project which was able to extract copperprofitably from the waste dumps while preventing water quality degradation. A further example is providedby INCO which developed its smelting technologies in response to new legislation from the OntarioEnvironment Ministry. The company has embarked on an aggressive technology licensing initiative tocommercialise its new technologies in other copper and nickel-producing countries, with six agreementssigned by 1994.

THE LIMITATIONS OF CURRENT REGULATORY APPROACHES

Although successful in focusing attention on environmental performance, regulatory approaches have tendedto discourage innovative responses to the environmental imperative. Rather than seeking innovative waysto reduce environmental damage costs, regulations instead have assumed the technology and organisationof production (and therefore the environmental damage costs) to be static, and have focused on thedistribution of these fixed environmental damage costs among stakeholders. Hence the concept of theenvironmental trade-off: either society suffers from pollution or industry internalises the environmentaldamage costs associated with pollution. Approaches to regulation which promote pollution control throughBest Available Technology (BAT), for example, are based on the assumption that emissions and wastematerials are an inevitable part of production and that the environmental impacts of these emissions canbe most effectively controlled through pricing to internalise environmental damage costs and make thepolluter pay. BAT controls have proved very effective at reducing pollution after their initial application,but they create a situation of technology lock-in where a company has litt le incentive to find alternative,innovat ive ways to comply with environmental performance standards. There is also no guanmtee that onceitems of BAT are in place environmental performance will be sustained and improved over time. Although

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Improving environmental perform ance hrough innovation 911add-o n controls car[ have relat ively low capi tal costs , ret rofit ting tends to increase produ ct ion costs byreducing p roces s efficiency and offering li tt le f lexibi li ty for further improvem ent . As regulatory s tandardschange, so new devi ices (and further capi tal costs) are required to achieve the permit ted leve ls of discharge.There is growing recogn i t ion that technological innovat ion can be s timulated by an environmentalregulatory fra me work in whic h compliance co sts are offset by product ivi ty gains [10, 11]. The objec t iveof such regulat ion is not s imply to control pol lut ion and dis t r ibute the costs , but to reduce pol lut ion atsource. T he chemic, ls sector has led this revolut ion in approaches to waste management through sev eralinnovat ive p rogrammes , no tab ly Minneso ta Min ing and Manufac tu ring ' s (3M ) ' "3P" p rog ramm e--Pol lu t ionPreve nt ion Pay s. Re-regulat ion to reduce total environmental damage c osts by encouraging p ol lut ionpreven t ion through investm ent in new product ion technologies and organisational pract ices has em ergedas a po l i cy ob jec t ive in severa l coun t r i es (e .g .U .S . Po l lu t ion Preven tion Act o f 1990 , U .S. B ureau o fM ines Guidel ines f i3r Pol lut ion Prevent ion in Mining and Mineral Processing). Several regulatory reg imeshave b egun to incorporate s trategies for source reduct ion and pol lut ion prevent ion into their environmentals tatutes . Typ ical provis ions include requirements to improve uni t eff icieneies, m odify or el iminateprod uct ion s teps , and change, subst i tute, or modify product ion input materials [9]. Few pol icies , howe ver,have establ ished systematic incentives for industry to innovate and develop new environmental techn ology,and in pract ice pol lut ion prevent ion legis lat ion has cont inued to focus on internal is ing fixed environmentaldamage costs rather than reducing them through innovat ion in the product ion process .Re gulatory po l icy has some w ay to go in furthering the aims of pol lut ion prevent ion, but there is evidenc eto suggest that some of the mo re dynam ic companies in the international mining industry are deve lopingand invest ing in cleaner technologies in a shift away from e nd.of-pipe pol lut ion control techniques such asflue-g as scrubbe rs , dust precipi tators , o r waste water t reatment plants , tow ards a re-engineering of theprodu ct ion process i tself to reduce or even el iminate waste. E fforts to reduce SO 2 emiss ions f rom twodiffe rent F alconbr~idge smelters illustrate the site-specific n ature o f the innovation e ffor ts requ ired torespond to enviromalental regulat ion and are an indication that "Best Pract ice" rather than "B est Avai lableTec hnolo gy" s tandards are more appropriate regulatory instruments . Falconb ridge Ltd has reduced i ts totalSO2 emissions from an est imated 122,000 tones in 1980 to som e 63,500 tons in 1988 through acom binat ion of processes . At the Falconbridge smelter, whe re for technical reasons re cove ry of SO2 ispart icularly diff icul t , the approach has been through incremental improvem ents to exis ting techno logy. Incon t rast , Fa lconbr idge 's new K idd Creek e lec t ro ly t i c z inc p lan t was des igned and opera ted f rom the ou t se tto meet current an6 foreseea ble environmental constraints. The zinc concentrate is "fluid-bed" roasted but ,unl ike the partial roast ing of nicke l-cop per sulphides at Falconbridge, the Kidd Creek co ncentrate is "dead"roasted to oxidise a substant ial proport ion o f the sulphur to SO2 for acid product ion. SO2 emissions to theatmosp here are therefo re nominal. The by-p roduc t acid is used to leach oxide calcine to produc e a neutral,purif ied zinc sulphate solut ion for electrolysis to zinc cathodes [12].The high fron t-end costs and long-term nature of investment in pol lut ion prevent ion is dem onstrated byAlean InternationaL's recent programm e o f pol lut ion abatement and modernisation. Expe cted to cost morethan C$3 bi l l ion by the year 2015, the investment replaces horizontal Stud Sodeberg smelters in Quebe cwith mor e environm ental ly sophis ticated facil it ies , and modernises old pre-bake cel ls at i ts Arv ida Wo rks.One th ird o f the inves tment i s comm i t ted to the cons truc t ion o f a new 200 ,000 t /y Later ri e re smel ter inChicou t imi, which w il l gradual ly com e on s tream as older, m ore pollutant, capaci ty is shut down. This wil lenable the c om pany to el iminate vir tual ly all i ts emissions of toxic aromatic hydroc arbons.

I N N O V A T I O N F O R P O L L U T I O N P R E V E N T I O N I N S M E L T I N GThe non -ferrous raetals industry produces a range o f metals from their sulphide ores , no tably nickel ,copp er, zinc and lead. T he pyrometal lurgical t reatment of sulphide ores involves a control led oxida t ion ofthe sulphides to prod uce sulphur dioxide gas . In the t reatment of chalcopyri te, fo r exam ple, tw o tonnes ofsu lphur d iox ide gas are p roduced fo r every tonne o f copper . S u lphur d iox ide f rom smel ting and o thersources is a contributor to acid precipi tat ion, and has be en implicated in several ecological and heal thprob lems inc lud ing crop damage, fo res t d ie-back , the eros ion o f masonry , and resp i ra to ry com pl ica tions

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912 A. Warhurst and G. Bridgein humans. Toge ther with a s teep rise in energy prices during the 1970s, the demon strat ion of the l inkagebet we en sulphur dioxide emissions and acid precipitation has challenged the smelting indus try to find wa ysof reducing sulphu r dioxide emissions while continuing to be viable in a very com peti t ive world m arket.The dev elopm ent of smelt ing technology exemplif ies the shift away from retrofi tt ing pol lut ion controlstoward s the redes ign o f the p roduct ion p rocess fo r cos t -ef fec t ive po l lu tion p reven t ion . Unable to meetincreasingly stringent air quality standards during the 1970s and 1980s, ope rators of rev erbe rator y furnaceshad the cho ice of closing the operat ion al together, retrofit ting the reverberatory furnace w ith acid plantequipm ent and an oxy -fuel react ion shaft , or investment in oxygen-flash smelting technology . R e-engineering the product ion process through investment in f lash smelt ing has enabled improvements inefficiency and produc t ivi ty to be com bined with a reduction of emissions and environmental comp liancecosts over the long term. The Hlsm elt process for i ron ores 'i llustrates the econom ic efficiencies of investingin pol lut ion prevent ion. Init iated as a research project betwe en CRA and K loeckner Stahlwe rke in 1981,the proce ss is able to smelt i ron ores direct ly in a s ingle s tage and consis ts of closed molten bath reactor,eliminating the nee d for blast furnace, cok e ove ns, and sinter plants. A large scale researc h plant iscurrent ly opera ted by CR A and M idrex Corpo rat ion and has the potent ial to substant ial ly imp rove theeco nom ics of steel making and result in significant environmental imp rove me nts.Considerable progress towards pol lut ion prevent ion in the smelt ing industry has been made over the las tfew yea rs through the redesign o f the product ion process fo r sulphide ores to faci li tate sulphur dioxidecapture and i ts efficient co nversion. In seeking to meet the challenge posed by com peti t ive market pressuresand regulatory and societal demands for bet ter environmental perform ance, new technologies haveimpro ved pro cess efficiency and cut emissions by reducing the numbe r of s tages in the smelt ing process ,increasing the concentrat ion of sulphur in the off-gas , and enclosing the process so as to make the captureof off-gases as efficient as possible. Additional methods fo r reducing the atmospheric impacts of sulphurdioxide include im provem ents in the efficiency of conversion to sulphuric acid ( the m ost popular opt ion,but constrained b y the need for proximate markets) , improving ore feed qual i ty by reject ing i ron sulphidesof low metal value, and the product ion of elemental sulphur ei ther direct ly through the metal extract ionproce ss (e.g . the ferric chloride leach process for the treatment of concentrates from com plexlead-zinc-copper-s i lver sulphide ores) or indirect ly through SO 2 conversion. Noran da Minerals Inc, fo rexample , has reduced SO2 emissions at i ts seven metallurgical facil it ies from 800,00 0 tonnes pe r year in1970 to 270,000 tonnes per yea r in 1990 by adopting smelter technologies that redu ce SO 2 produc t ion, andby increasing the conversion to sulphuric acid which is sold as a by-produ ct [13]. Inco Ltd has also beenwork ing fo r a num ber o f years to reduce SO2 emissions at i ts Sudbury operat ions. P rogress has been m adeby reject ing m ore pyrrh ot i te in the mil ling operat ions and the introduct ion of new flash smelter technolog iesto faci li tate sulphuric acid product ion. The latest phase of their Sulphur Dioxide A batemen t Pro ject isexpected to reduce SO2 emissions further through the commissioning of a f lash converter for high copp ermatte and a modified gas cleaning system [14].INCO Flash Smelt ing TechnologyIN CO 's developm ent of oxyge n flash smelting technology is an example o f radical technical changenecessi tated b y the exhaust ion o f possibi l it ies for further efficiency improvem ents in convent ionaltechnologies . Unti l recent ly one of the wo rld 's highest cost nickel producers , INC O was the greatest s inglesource o f environmental pol lut ion in North A merica as a resul t of an aged and inefficient revcrbe ratoryfurnace sm elter at Sudbury, Ontario which em it ted excessive volum es of SO 2. Having reached the l imitsof efficiency improv eme nts in this obsolete technology, and unab le to meet increasingly s tr ingentregulat ions as part of an intensive acid rain abatement program me by the Ontario Environm ent M inis t ry,INC O inves ted over C$3 ,000 mi l l ion in research and development . The INC O ox ygen f lash smel terp roduces a concen t ra ted SO2 off-gas s t ream which c an be efficient ly captured and fixed as sulphnric acid.In addi t ion the f lash smelting process ut i l ises the exotherm ic propert ies o f sulphide ores and requires v eryl i t tle addit ional fuel . The pro cess efficiencies s temming from the appl icat ion of the technology have noton ly reduced SO 2 emiss ions a t S udbury by over 100 ,000 t /pa , bu t have he lped t rans form the company in toone of the w or ld ' s lowes t cos t p roducers [ lO] .

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Improving environmentalperformance hrou gh innovation 913

K e n n e c o t t / O u t o k m n p u O y F l a s h S m e l t e r , G a r f i e l d , U t a h

T h e d ev e l o p m en t o f a n ew g en e r a t io n o f f l as h s m e l t in g / f la s h co n v e rt i n g b y K en n eco t t an d O u t o k u m p u O yat Gar f ie ld , U tah h ,Ls been he ra lded as the "c leanes t smel ter in the wor ld " an d as such , one o f the mos ts ign i f ican t innovat ions in minera l p rocess ing in r ecen t t imes . The new smel ter and conver ter complexrep laces an ex is t ing f ac i l i ty whic h was ab le to hand le o n ly 60% of the concen t r a tes p rodu ced a t theB i n g h am C an y o n m i n e . T o m ee t i n c r ea s i n g ly t o u g h a i r q u al it y, reg u l a t io n s , t h e co m p an y w as f aced w i t ha cho ice o f inves t ing $150 mi l l ion in po l lu t ion con t ro l t echno logy and being cons t r a ined by the ex is t ingsmel ter capaci ty , o r inves t ing $880 mi l l ion on a new process . The new process increased the capaci ty o fthe sm el ter to hand i [e 100% of the concen t r a tes , the reby e l iminat ing t r anspor ta t ion and p roc ess ing cos tsassocia ted wi th the sh ipm ent o f concen t r a tes to Paci f ic Rim smel ter s , and enab l ing the p lan t to meet o rexceed a l l ex is t ing and an t ic ipa ted a i r qual i ty r egu la t ions . I t i s an t ic ipa ted tha t the new p lan t w i l l r educeopera t ing cos ts by 53% [15]. T he p r inc ipa l f ea tu res o f the new complex are the r ep lacement o f t r ad i t ionalPierc e-Sm i th co nver ter s w i th a pa ten ted f lash conver ter , th e to ta l enclosure o f the conver ter , and therep lacem ent o f open-a i r l ad le t r ans fer o f mol ten m at te w i th a so l id - s ta te t r ans fer . M ol ten m at te i s coo ledwi th w ater in to a g ranu la ted fo rm pr io r to t rans fer to the conver ter s , s ign i f ican t ly r educing the r e lease o fsu lphu r d iox ide and o ther gases in the t r ans fer p rocess. A l tho ugh the coo l ing o f the mat te invo lves a losso f h ea t en e r g y , " w as t e " h ea t i s c ap tu r ed a s s t eam an d f ed to a co - g en e r a t io n u n i t . T h e s e l ec ti o n o f f l as hco n v e r t i n g en ab l e s a co n t i n u o u s h i g h t h r o u g h p u t o f m a te r ia l an d a m u ch i n c r ea s ed co n cen t r a t i o n o f s u l p h u ri n t h e o f f - g a s , g r ea t l y i m p r o v i n g t h e e f f i c ien cy o f s u l p h u r cap t u re . I n co m b i n a t i o n w i t h t h e w o r l d ' s l a rg es td o u b l e co n t ac t a c i d p l an t , an n u a l av e r ag e em i s s i o n s o f s u lp h u r d i o x i d e w i l l b e r ed u ced f r o m 3 ,6 0 0 p o u n d sper h our to 200 per h our [ 16 , 17].A t the t ime tha t Keu neco t t was ev aluat ing op t ions to increase sm el t ing capaci ty , the Sta te o f U tah adop teds ign i f ican t ly more : r es t r ic t ive r egu la t ions fo r the con t ro l o f SO 2 and P M lo par t icu la tes I as par t o f theE n v i r o n m e n t a l P r o t ec t i o n A g en cy ' s m an d a t ed S t a te I m p l em en t a t i o n P l an ( S IP ) f o r co m p l i an ce w i t h t h eFed e r a l C l ean A i r A c t . T h e n ew r eg u l at i o n s req u i r ed th a t SO2 b e l i m i t ed t o 1 6 ,85 0 t / y an d P M I o t o 1 ,2 1 6t / y . T h e s m e l t e r ' s ex i s t i n g SO2 em i ss i o n s h ad av e r ag ed 2 0 ,0 5 0 t / y , w i t h PM t o em i s s i o n s o f ab o u t 8 0 0 t / y .C o m p l i an ce w i t h t h e n ew r eg u l a ti o n s w o u l d h av e r eq u i r ed a d ec r eas e i n th e o l d s m e l t e r 's o p e r a t i n g cap ac i tyand r ep lacem ent o f the s ing le-con tac t ac id p lan ts . Fur therm ore , modi f ica t ions to tha t smel ter were l ike lyto be inadequate to me et more r es t r ic t ive r egu la t ions expected af ter the mid-1990s . The s t r a tegy develope dfor the new sme l ter was to ins ta l l the bes t avai lab le emiss ion con t ro l equ ipm ent an d min im ise the need fo rp rogress ive mod i f ica t ions to the f ac i l ity in the fu tu re . W i th the new sm el ter ab le to cap tu re 9 9 .9% of inpu ts u l p h u r , K en n e co t t w as ab l e t o p r o p o s e t o t h e U t ah D ep a r t m en t o f A i r Q u a l i ty an em i s s io n l i m i t o f 9 8 2t / y ( 1 1 2 k g / h ) f o r SO 2, a 50% reduct ion in PM10 l imi t s , and ac id mis t emiss ions r educed by approx imate lyone- th i rd . Em iss ions o f n i t rogen ox ides (NOx) were a l so r educed s ign i f ican t ly by us ing u l t r a- low NO xburner s in a l l app l ica t ions . Ex ceed ing com pl iance r equ i r emen ts and es tab l i sh ing emiss ions s tandards be lowt h o s e o f t h e D ep a r t m en t o f A i r Q u a l i t y f aci l it a t ed th e p e r m i t ap p r o v a l p r o ces s w h i ch w as ex p ed i t ed t o o n l yf ive mo nths [ 18].

" L E A N A N D C L E A N " P R O D U C T I O N T H R O U G HI N N O V A TI O N IN P R O C E S S C O N T R O LT h e p o l i cy o f Po l l u t i o n P r ev en t i o n Pay s r eco g n i se s t h a t s u cces sf u l p o l lu t i o n p rev en t i o n can i m p r o v e aco m pan y ' s competiL tive pos i t ion as wel l as i ts env i ronm enta l per fo rma nce . The p r inc ipa l m echa n ism byw h i ch p r ev en t i n g p o l l u t i o n is j u d g ed t o i m p r o v e co m p e t it i v en es s i s t h r o u g h i m p r o v em en t s t o r e s o u r ceprodu ct iv i ty ( a l though o ther , l ess tang ib le benef i t s such as improved access to cr ed i t and exped i tedp e r m i t t i n g m ay a l s o b e i m p o r t an t - - s ee ab o v e ) . T h e r e s o u r ce p r o d u c t iv i t y a rg u m en t h o l d s t h a t em i s s i o n sand wa s te mater ia l s a r e , in essence , was ted r esources and as such po l lu t ion i s an ind ica to r o f inef f ic iency

'PMIO refers to part ic les o f less than 10 microns in size which are judged to be a more serious health r isk than larger panicles .

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914 A. W arhurstand G. Bridge[10 , 11 , 19] . Improv ing ef f ic iency r educes cos ts and was te per un i t o f ou tpu t and improves env i ronm enta lp e r f o r m an ce s o t h a t an e ff i ci en t " l ean " co m p an y i s n o t o n l y co m p e t i ti v e b u t a l s o " c l ean " .A prerequ is i te to impro v ing ef f ic iency and env i ronm enta l per fo rma nce i s a h igh level o f p rocess co n t ro l .Process con t ro l i s the techno log ica l and manager ia l capaci ty to con t inuous ly ad jus ted p rocess cond i t ionsso as to op t imise overa l l per fo rman ce . Ach iev ing p rocess con t ro l re l ies on the mo ni to r ing and p rocess ingof r e l iab le , r ea l - t ime in fo rmat ion on opera t ions and the capaci ty to ad jus t and main ta in des i r ed levels o fper fo rma nce . The microelec t ron ics r evo lu t ion has enab led g rea ter degrees o f p rocess con t ro l than wereformer ly poss ib le th rough an increased capaci ty fo r moni to r ing ( e .g . the development o f ins t r eam sensor sand par t ic le s ize moni to r s ) , r ap id da ta analys i s , model l ing , and computer au tomat ion [20] . F lo ta t iontechno log ies , fo r example , have been used s ince the 1920s , bu t i t was no t un t i l the ear ly 1980s tha tau tom ated co n t ro l sys tem s became avai lab le which enab led a f ine- tun ing o f the f lo ta t ion p rocess to op t im isei t s per fo rmance . The in t roduct ion o f an exper t sys tem to con t ro l r eagen t use in f lo ta t ion a t ASARCOSw ee t w a t e r an d D o e R u n i n M i s s o u r i h a s en ab led a r ed u c t i o n o f reag en t u s e an d , a s a r e s u l t o f i m p r o v i n gthe qual i ty o f concen t r a te p ass ing to the sme l ter , decreased smel ter emiss ions per un i t o f ou tpu t [21]. Asp a r t o f a p r o g r am m e f o r ev a lu a t i n g th e o p t io n s f o r s m e l t e r m o d e r n is a t io n , C A N M E T h as b een w o r k i n gw i t h t h e n o n - f e rr o u s s m e l t in g i n d u s t r y , E n v i r o n m en t C an ad a , an d I n d u s t r y , Sc ien ce an d T ech n o l o g yCan ada to develop a ceramic-based sensor fo r concen t r a t ions o f SO2 and SO 3 gases in a n ef fo r t to op t imisep r o cess co n t r o l . Sen s o r s h av e a l r ead y b een d ev e l o p ed f o r t h e co n t i n u o u s m eas u r em en t o f o x y g en i n co p p e rcas ter s and lead b las t fu rnaces wi th the a im o f mod ern is ing smel ter s and op t imis ing the i r opera t ion toreduce subs tan t ia l ly SO 2 emissions and metal losses [14] .J a m e so n Cd l T e c h n o l o g y - -M t . I sa M i n es ( M IM )T h e J am es o n C e l l ex em p l i f ie s h o w i n n o v a t i o n t o i m p r o v e r e s o u r ce p r o d u c t i v i t y an d ach i ev e g r ea t e r l ev e l so f p r o cess co n t r o l c an a l s o i m p r o v e t h e en v i r o n m en t a l p e r f o r m an ce o f a m i n e r a l p r o ces s in g p l an t . T h eJ am es o n ce l l ( ex c lu s i v e m ar k e t i n g r i g h t s to w h i ch a r e h e l d b y M I M h o l d i n g s ) h a s a w i d e r an g e o f m i n e r a lp rocess ing a pp l ica t ions . A s an a l te rna t ive sepa ra t ion p rocess to co lum n f lo ta tion , the ce l l ach ieves a h ighe rco n cen t r a t i o n o f f ro t h v i a a s i m p l e " d o w n co m er " d ev i ce i n w h i ch a i r an d l i q u i d m i n e r a l f eed a r e i n t r o d u cedtogethe r a t the top o f the f lo ta t ion ce l l r a ther than a i r a t the bo t to m as in conven t ional f lo ta t ion . Th e ef f ec ti s to increase f ro th genera t ion and , as a consequence , to improve the r a te o f meta l r ecovery . T hetechn o logy has been wide ly used in Aus t r a l ia fo r such d iver se app l ica t ions as improv ing r ecover ies in thelead /z inc concen t r a to r a t Mt . I sa Mines , fo r the r ecovery o f coal f ines which p rev ious ly had been sen t aswas te to ta i l ings a t Newlands coal mine , and fo r concen t r a te c lean ing a t the Peko Mines copperconcen t r a to r . T he techno lo gy a l so has been f avourab ly app l ied a t copper p rocess ing f ac i l i t ies in the U .S . ,Canada , and I ta ly where i t i s ab le to improve hydrocarbon and r eagen t r ecovery a t so lven tex t r ac t ion-e lec t rowinn ing (SX-EW) p lan ts . Reagen t non- recovery can r epresen t a subs tan t ia l componen tof opera t ing cos ts a t SX-EW p lan ts , and the p lacement o f the ce l l be tween the SX and E W s tages enab lesthe r ecovery o f r eagen ts f rom the aqueo us r af f ina te . In add i t ion to improv ing the econom ics o f r eagen t use ,t h e J am es o n ce l l r em o v es r eag en ts w h i ch w o u l d o t h e r w i se b e ca r ri ed f o r w ar d i n t o t h e e l ec t ro w i n p l an t ,thereby f ac i l i t a t ing the imp rovem ent o f fina l p roduct qu al i ty . O ther p romis ing a pp l ica t ions o f the Jameso nCel l inc lude an t imony c lean ing , copper ox ide and go ld f lo ta t ion , and the r ecovery o f z inc f rom ta i l ings[38].N e w C o n t r o l T e c h n o lo g i es f o r R e f r a c t o r y G o l d P r e - T r e a t m e n tR e f r ac t o r y g o l d o r e s - - t h o s e t h a t d o n o t r e sp o n d w e l l to s i m p l e cy an i d a t i o n w i t h o u t p r e t r ea tm en t an d a r etyp ica l ly pyr i t ic , a r senopyr i t ic o r carbon aceou s- -have r ece ived increas ing a t ten t ion in the Uni ted Sta tes w i ththe d iscovery tha t many near - su r f ace ox id ised depos i t s a r e under la in by la rge go ld -bear ing su lph ide( r e fr ac t o ry ) d ep o s i t s. C o m m o n p r e t rea t m en t m e t h o d s f o r r e f rac t o r y o r e s a r e m as t i n g , p r e s s u r e o x i d a t i o n ,and b ioox idat 'on . Ch lor ina t ion p re t r ea tment i s a l so u t i l i sed to t r ea t r e f r ac to ry go ld o res con ta in ingcarbonaceou s m ater ia l s a t some m ines , a l thoug h it s app l icab i l i ty i s limi ted due to the requ i r em ent for lowsu lphur in the o re in o rder to min imise ch lo r ine consum pt ion . Th e p r inc ipa l env i ronmenta l i s sues associa tedwi th p re t r ea tment ar e the cap tu re o f su lphur , a r sen ic , mercury and par t icu la tes , w i th o ther po ten t ia lpo l lu tan ts ( such as an t imony) o f poss ib le impor tance depend ing on the speci f ic o re minera logy . The

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Improving environmental performance hrough innovation 915s e l e c t i o n o f a p r e t r e a t m e n t t e c h n i q u e d e p e n d s u p o n m i n e r a l o g y , t h e e c o n o m i c s o f m i n e r a l r e c o v e r y ,p o s s i b l e e n v i r o n m e n ' ta l i m p a c t s , a n d t h e i n d u s t r y ' s a c c e p t a n c e o f t h e t e c h n o l o g y a s p r o v e n . I n r e c e n t y e a r st h e e n v i r o n m e n t a l a s p e c t o f m i n e r a l p r o c e s s i n g h a s b e c o m e o f in c r e a s i ng i m p o r t a n c e i n t h e s e l e c t i o n o ft r e a t m e n t r o u t e s .

A r e c e n t s t u d y b y th e U . S . B u r e a u o f M i n e s c o m p a r e d t h e e n v i r o n m e n t a l c o n t r o l t e c h n o l o g y r e q u i r e m e n t sa s s o c i a t e d w i t h r o a s t i n g , p r e s s u r e o x i d a t i o n , a n d b i o o x i d a t i o n [ 2 2 ] . W i t h t h e e x c e p t i o n o f b i o o x i d a t i o n ,a t m o s p h e r i c e m i s s i o n s w e r e f o u n d t o b e t h e m o s t s i g n i f i c a n t a r e a i n w h i c h e n v i r o n m e n t a l c o n t r o lt e c h n o l o g y w a s r e q u i r e d . A l l t h r e e p r e t r e a t m e n t p r o c e s s e s r e q u i r e a d e g r e e o f li q u i d e ff l u e n t c o n t r o l , w h i l er o a s t i n g c a n r e q u i r e t h e g r e a t e s t o v e r a l l p o l l u t i o n c o n t r o l e f f o r t . R o a s t i n g c a n b e e s p e c i a l l y p r o b l e m a t i cb e c a u s e p a r t i c u l a t e s , S O 2 , H g , a n d A S 2 0 3 i n fl u e g a s r e q u i re a c o m p l e x a n d e x p e n s i v e g a s t r e a t m e n ts y s t e m . I n a d d i ti o n t h e e c o n o m i c s o f ro a s t i n g n e c e s si t a t e p r e p a r a t o r y d r y g r i n d i n g o f t h e o r e w h i c h c a n b ea n a d d i t i o n a l s o u r c e o f p o te n t i a l p o l l u t a n ts . B y c o m p a r i s o n p r e s s u r e o x i d a t i o n i s a r e la t i v e l y c l e a n p r o c e s sw i t h p o t e n t i a l e m i s s i o n s l i m i t e d t o p a r ti c u l a t e s a n d S O 2 . E n v i r o n m e n t a l c o n s i d e r a t i o n s w e r e a m a j o r d r i v i n gf o r c e b e h i n d t h e d e v , e l op m e n t o f b i o o x i d a t i o n p ro c e s s e s f o r t r e a t m e n t o f re f r a c t o r y g o l d o r e s . B i o o x i d a t i o ni s t h e c l e a n e s t o f t h e t h r e e p r o c e s s e s , r e q u i r e s t h e l e a s t e n v i r o n m e n t a l c o n t r o l t e c h n o l o g y , a n d h a s t h el o w e s t e n v i r o n m e n t ~ d c o n t r o l c o s t s .A s o x i d e g o l d o r e d e p o s i t s a r e d e p le t e d r e f r a c t o r y g o l d o r e s w i ll b e c o m e i n c r e a s i n gl y i m p o r t a n t , a n d t h i si s a l r e a d y r e f l e c t e d : in t h e n u m b e r o f r e f ra c t o r y g o l d p r e t r e a t m e n t p l a n t s b e i n g c o n s t r u c t e d i n t h e U n i t e dS t a te s : f i v e g o l d p r e s s u r e o x i d a t i o n p l a n t s w e r e c o n s t r u c t e d s i n c e th e m i d - 1 9 8 0 s , a n d f o u r n e w r o a s t i n gp l a n t s h a v e b e e n c o n s t r u c t e d o v e r t h e l a s t f i v e y e a r s w i t h t w o m o r e u n d e r c o n s t r u c t i o n . L a r g e - s c a l ea p p l i c a t i o n s o f b i o - h e a p l e a c h i n g a r e s t i l l i n th e d e v e l o p m e n t a l s t a g e i n t h e U n i t e d S t a te s , w i t h o n g o i n gr e s e a r c h i n t o t h e d e v e l o p m e n t o f n e w s t r a in s o f b a c t e r ia . O n e m a j o r U . S . g o l d p r o d u c e r h a s a n n o u n c e dp l a n s t o c o n s t r u c t a w h o l e o r e , h e a p l e a c h b i o o x i d a t i o n p l a n t a t i t s C a r l i n , N e v a d a , o p e r a t i o n s a n d s e v e r a lo t h e r U . S . g o l d o p e r a t o r s a r e a t t e m p t i n g s m a l l - s c a l e b i o o x i d a t i o n o f re f r a c t o r y g o l d o r e s [ 2 3 ] .T h e S ~ o B e n t o M i n e r a c ~ o c o m p a n y s e l e c te d p r e s s u r e o x i d a t i o n t e c h n o l o g y f o r t h e r e c o v e r y o f g o l d f r o ma r e f r a c t o r y o r e b o d y p r i m a r i l y o n t h e g r o u n d s o f i ts s u p e r io r e n v i r o n m e n t a l c h a r a c t e r i s ti c s . T h e o r e f e e dc o n t a i n s 2 0 p e r c e n t s u l p h u r a n d 1 5 - 1 8 p e r c e n t a r s e n i c a n d w e r e t h e h i g h e s t l e v e l s e v e r t o b e t r e a t e d i nB r a z i l . S i n c e B r a z i l i a n l e g i s l a t io n d o e s n o t a l l o w f o r th e a t m o s p h e r i c d i s c h a r g e o f s u l p h u r a b o v e8 0 m g / N M 3 o r t h e r e le a s e o f a r s e n i c i n t o d r a i n a g e i n c o n c e n t ra t i o n s a b o v e 0 . 2 m g / l i t r e , t h e i r r e c o v e r y a n dt r e a t m e n t w a s a n e s s e n ti a l p a r t o f t h e p r o c e ss . T h e c a p i t a l c o s t s o f p r e s s u re o x i d a t i o n w e r e a b o u t 2 5 p e rc e n t h i g h e r t h a n t h e a l t e r n a t iv e f l u o s ol i d ro a s t i n g p r o c e s s b u t a c h i e v i n g e f f e c t i v e p o l l u t i o n c o n t r o l w o u l db e su b s tan t ia l ly le s s ; d i f f icu l t. T h e p r es su re o x id a t io n p ro cess p ro d u c es a l iq u id e f f lu en t o n ly , a d i s t in c ta d v a n t a g e o v e r th e r o a s t i n g a l t e r n a t iv e w h i c h p r o d u c e s g a s e o u s a n d l i q u i d e f fl u e n ts . T h u s , t a k i n g i n t oa c c o u n t t h e s e r i o u s e n v i r o n m e n t a l a n d p l a n t h y g i e n e p r o b l e m s a s s o c i a t e d w i t h t h e r o a s t i n g o f c o n c e n t r a t e sa t t h o s e v e r y h i g h l e v e l s o f a r s e ni c , t h e p r e s s u r e o x i d a t i o n r o u t e w i t h i t s in h e r e n t c l e a n l i n e s s w a sp r e f e r r e d 2 . I n t h e o 3 n t e xt o f a n e v o l v i n g e n v ir o n m e n t a l r e g u l a t o r y f r a m e w o r k t h is c h o i c e w a s a l s o s e e na s a m e a n s t o a v o i d f u t u r e f i n a nc i a l p e n a l t ie s 3 . S ~ o B e n to M i n e r a c ~ o o f f e r s o n e o f t h e f e w e x a m p l e s o f ad e v e l o p i n g - c o u n t r y c o m p a n y w h i c h h a s in c o r p o r a t e d i m p r o v e d e c o n o m i c a n d e n v i r o n m e n t a l e f f i c ie n c y i n t oa n e w l e a c h i n g o p e r a t i o n , a n d t h e c o m p a n y i s c u rr e n t l y p l a n n i n g t o d o u b l e i t s p r o d u c t i o n a n d a t t h e s a m et i m e i n t r o d u c e b a c t e r i a l o x i d a t i o n t o a u g m e n t t h e p r e s s u r e o x i d a t i o n p r o c e s s [ 1 0 , 2 4 ] .

2Another feature of the projectwas an environmentalcondition stipulated by the equipment supplier, which was tha t the arsenic levelin the effluentwould have been required to mee t he level specified n the country of origin of the technology. The refore, the Swedishspecification of 0.05mg/NM3 was applicable. These conditions remain to be met by the plan t, although its discharges fall withinBrazilian lim its, achiev,:l hrough lim e ferric arsena te precipitation.3 Like the H omvstakegold mining operation at McLaughlin mine, a series of environmental controls were built into the Sic Bentomine from the outset. The mining areas have all been terraced. Afa r completion of the cut and fill excavation procedure, terracesare landscaped and spraye dwith a hydroseal mixture of indigenous grass seed, fertilizer and w ater. A secondary growth of trees hasalso started. Abou t 50 per ce nt of barren tailings are placed as back-fill n the stoppe dout areas, the remainderare c ollected in tailingsdam s, and ex cess water itsrecycled o the plant for treatment prior to discharge. Finally, monitoringof water samples from boreholesnear the tailings dam is undertaken fortnightly unde r COPAM (Environmental Policy Council) guidelines.

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916 A. Warhurstand O. Bridge

MANAGING TECHNOLOGICAL CHANGE: BIOLEACHINGThe development of heap, dump, vat and in-situ bioleaching for a range of non-ferrous metals hasrevolutionised metal recovery techniques enabling the processing of low grade and chemically complexores. In addition to having lower capital and operating costs and being flexible in scale, bio-leaching is apotentially cleaner production process for many metals, since it can obviate the need for the energyintensive and traditionally polluting roasting, smelting, and refining stages. Bioleaching utilises a particulargroup of bacteria (the obligate chemolithoautotrophs) which obtain energy through the oxidation ofinsoluble inorganic sulphides or ferric iron [25, 26]. The bacteria occur naturally, and are responsible forthe processes which generate acid mine drainage. Productive use of the bacteria's oxidation of sulphideminerals has been made since Roman times, but it has only been in the last two decades that a series ofincremental improvements have enabled bioleaching to become a large-scale commercial prospect.Important advances include an increase in the capacity of earth moving equipment facilitating dump andheap leaching, developments in ion-exchange technology to improve the concentration ofraff inate solutionsto the point at which they can be efficiently electrolysed, and improvements in procedures for data analysis,modelling, and process control sufficient to produce a consistently high quality product. To date bioleachinghas been applied commercially to the recovery of gold, uranium, copper, and nickel.B I O X a n d B i o N IC

Gencor pioneered the BIOX process for the biological oxidation o f sulphide gold deposits in laboratoryresearch during the late 1970s and by 1986 a full-scale commercial plant was operating at Fairview inSouth Africa, In the BIOX process ore is crushed to liberate sulphide minerals from gangue, then floatedto produce a concentrate. The concentrate is fed to slurry tanks containing bacteria (Th iobaciUusferrooxidans) in which temperature, oxygen and pH conditions are controlled to achieve an optimum rateof reproduction. Average residence time for the slurry is four to five days, after which it is thickened andtreated in a conventional cyanidation plant. Arsenic in the ore is recovered in the solution from thethickeners and precipitated as inert and environmentally stable ferric arsenate suitable for tailings disposal[25]. The advantages of the process over conventional treatments are its reduced capital and operatingcosts, improved recovery rates which are not constrained by grade, very robust bacteria able to withstandconsiderable variations in ambient conditions, and the potential to be a non-polluting process. Gencorreports that the replacement of roasters with the BIOX process at Fairview contributed significantly tosolving the problems o f sulphur dioxide and arsenic trioxide pollution. Gencor 's bioleaching technologyis licensed to other producers, with the first licensed plant commissioned at Ashton's Harbour Lights inWestern Australia in 1991. This was followed by ASARCO's Wiluna plant in 1993, and AshantiGoldfield's Sansu Mine in 1994. At 1 Mt/y, Ashanti is the largest BIOX installation and has been verysuccessful with recovery rates o f over 94 % (direct cyanidation yielded 5-40 %). The success of the processhas led Gencor to a review its policy of technology licensing, and opt for a programme of equityparticipation, such as the planned joint venture between Gencor and Lonrho at Yamantoto in Uzbekistan.In the last five years Gencor has pioneered the bioleaching of nickel sulphides. The BioNIC processprovides a means of treating nickel sulphides where the head grade is too low to allow sufficientconcentration. It avoids the need to roast ores and provides an effective way of dealing with high levelsof impurities such as arsenic which currently prevent the development of many nickel sulphide ores.BioNIC is a three stage process: the bioleaching of concentrates to take metals into solution; ion exchangeand solvent extraction to separate iron and nickel into a pure solution; followed by electrowinning to yielda pure ferronickel product. Arsenic is taken off in solution and precipitated out in the same manner as theBIOX process. In 1994 Gencor entered into a joint venture with an Australian producer, Maggie HaysNickel, in which Gencor will supply BioNIC process technology to the Lake Johnston nickel project inWestern Australia. The venture will significantly reduce processing costs, avoid many of the environmentalproblems of conventional nickel processing technologies, and produce a high-grade ferronickel that can befed directly to stainless steel plants.

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Improving environmentalperformance llrough nnovation 917N e w m o n t ' s He a p B i o l e ac hN ew m o n t G o l d ' s i n t t o v a ti v e ap pr o ach t o b io l each i n g co m b i n es b i o o x i d a t i o n w i t h a p a t en ted am m o n i u mth iosu lphate t r ea tment as an a l te rna t ive to cyan idat ion fo r r ef r ac to ry o res . Ores ar e p re- t r ea ted by b io -o x i d a t i o n ( u s i n g a m i x t u r e o f ThiobaciUus errooxidans and Leptospirillum erroo xidans) fo r four to s ixm o n t h s p r i o r t o l e ach i n g w i t h am m o n i u m t h i o s u l p h a te . T h e t ech n o l o g y ex ten d s t h e g r ad e r an g e f o r g o l d ,m ak i n g v i ab l e t h e r e - m i n i n g o f w as te d u m p s . A 5 0 0 ,0 0 0 t / y t w o - s t ag e h eap l each p ro ces s h a s b een u s eda t M t L ey s h o n G o l d M i n e , 2 4 k m s o u t h o f C h a r te r s T o w er s , n o r t h e r n Q u een s lan d , s i n ce A u g u s t 1 99 2 ,t r ea t ing copper /g o ld o re . The p rocess emp loys a f ir s t s tage bacteria l heap leach to r emove the copper p r io rto o re neu t r a l i sa t ion and a second s tage heap leach go ld ex t r ac t ion us ing cyan ide . Cons iderab le ox idat ionhas a l r eady taken p lace in a run-of -mine o re s tockp i le and , once p rocess ing s tar t s , secondary ox idat ionoccur s in a c rushed o re s tockp i le ass i s ted by the in t roduct ion o f bac ter ia , a i r and mois tu re . T he heaps ar es p r ay ed w i t h f r e sh w a t e r a t a r a t e o f 8 m m / h u s i n g a t w e l v e - h o u r - o n / tw e l v e - h o u r - o f f cy c l e . T h i s h a s b eenshown to ass i s t in main ta in ing copper g rades to the copper r ecovery p lan t whi le no t add ing to the overa l lt ime o f the ac id leach cy cle- - c ur r en t ly 45 days . N o su lphur ic ac id is added to the o re as a l l meta l s a r es o l u b i li s ed b y t h e ac i d p r o d u ced f r o m s u l p h i d e m i n e ra l o x i d a t i o n . C o p p e r m e t a l i s r eco v e r ed f r o m t h eacid ic leach so lu t ion by means o f cem enta t ion on to scrap s tee l [25].M I N B A C P ro c es sThe M INB AC bacte~r ia l ox ida t ion p rocess has been developed and p roven ove r the las t t en year s d ur ingw h i ch t i m e p r o ces s f u n d am en t a l s , b en e f it s o f p re - t rea t m en t , an d p r o ced u re s f o r t e st i n g t h e am en a b i l i ty o fo res to bacter ia l o x idat io n have been es tab l i shed . The p rocess i s ac t ive ly p rom oted by th ree in ternat ion alm i n e r a l o r g an i s a t i o n s ( M i n t ek , A n g l o A m er i can C o r p o r a t i o n o f So u t h A f r i ca , an d B a t em an P r o j ec tH o l d i n g s L t d ) w h i ch h av e j o i n ed f o r ce s t o p r o m o t e , d e s i g n , co n s t ru c t an d co m m i s s i o n b ac t e ri a l o x i d a t i o ng o l d p l an t s. M I N B A C p l an ts i n c l u d e a 1 t / d o r e ev a l u a t i o n fac i l it y lo ca t ed o n - s it e a t M i n t ek , an d a 2 0 t / dp l an t a t A n g l o A m er i can ' s V a l R ee f s m i n e . T h e o p e r a t i o n o f th e s e p l an t s , u s i n g a ThiobaciUusferrooxidans/Leptospirillumferrooxidans cu l tu re , has enab led an ex ten s ive da tabase o f p rocess k ine t ics andscale-up r equ i r ements fo r mix ing , aera t ion and coo l ing to be es tab l i shed . To date approx imate ly f i f tyref r ac to ry o res have been evaluated [25] .

I N N O V A T I O N F O R R E - M E D I A T I O N A N D R E -U S EA l t h o u g h m an y co m p an i e s a r e m o v i n g t o w ar d s p o l l u t io n p rev en t i o n t h r o u g h s o u rce r ed u c t i o n , t h e l eg acyof min in g opera t ions ( and o ther indus t r ia l ac t iv i ty ) in man y areas has le f t l and su f f ic ien t ly con tam inatedto fo rec lose p roduct ive r e-use . Regu la to ry p ressure to r ehab i l i ta te lands fo r env i ronm enta l , he a l th , andcom merc ia l r easons has encouraged innovat ion in the f ie ld o f c lean-up techno log ies . S ince any oneco m p an y w i l l h av e ~Lpor t fo l io o f opera t ive and abandoned p roper t ies (o f ten on the same s i te ) , ind iv idua lm i n i n g co m p an i e s m ay u s e a co m b i n a t i o n o f t e ch n o l o g ie s f o r en v i r o n m en t a l m an ag em en t . I n so m eci r cumstance s i t has /p roved poss ib le to combine c lean-up t r ea tme nt opera t ions wi th the recove ry and r e-useof sa leab le meta ls and minera ls . L iab i l i ty p rov is ions in the r egu la to ry f r am ewo rk , how ever , can mi l i ta teagains t th i s by increas ing the r i sk o f r e-min ing o r innovat ive was te u t i l i sa t ion schemes [27] .Innovative Smelter FeedstocksR eg u l a t o r y l i m i t a t i o n s o n w as t e d i s po s a l m e t h o d s i n t h e U .S . h av e g en e r a t ed s o m e i n n o v a t i v e ap p r o ach est o s l u d g e w as t e s. U n d e r t h e R es o u r ce C o n s e r v a t io n an d R eco v e r y A c t a d e f in ed s e t o f h aza r d o u s w as t e scan no t be d isposed o f th rough landf i l l . Dur ing the c lean up o f i t s Super fund s i te a t Cal i fo rn ia Gulch inC o l o r ad o , A SA R C O w as p r ev en t ed f r o m d i s p o s in g m e t a l -r i ch w as t e -w a t e r s l u d g e o n lan d . A s ea r ch f o ra l te rna t ive d isposal :methods led the company to in t roduce a cos t - ef f ec t ive p rocedure fo r u t i l i s ing s ludgeas a smel ter f eed s tock . Not on ly d id th i s innovat ive ap proa ch f ac i l i ta te c lean-up a t the s i te and p rodu cea so l id was te tha t cou ld be used as a l ime f lux r ep lacement a t ASARCO's lead smel t ing opera t ions , bu t i ta l so enab led the r ecovery o f sa leab le me ta ls [28]. T he developm ent o f the ver sa t ile ISA SM EL T processfo r the smel t ing o f copper in the la te 1970s has a l so enab led innovat ive sourc ing o f smel ter f eed . Co ns is t ing

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918 A. W arhurstand G. Bridgeo f a p a t en t ed l an ce d e s i g n w i t h o x y g en en r i ch m en t , t h e p r oces s n o t o n l y r ed u ces co a l an d o i l co n s u m p t i o n ,decreases fume emiss ions , and enab les an increase in ou tpu t , bu t i t can a l so t r ea t s lag concen t r a tes andthereby tu rn an o therw ise cos t ly was te p roduc t in to a r esource [29]. In add i t ion to copper , the p rocess h asbeen a pp l ied to lead and , fo l low ing the l icens ing in 1990 o f the techno logy to AG IP Aus t r a l ia , i t i s a l soapplicable to nickel [30] .T a i l i n g s Re -Us eA number o f r ef r ac to ry go ld opera t ions ar e r e-us ing was te pyr i te ta i l ings as an energy- feed fo r the i rau t o c lav es . H o m es t ak e ' s M cL au g h l i n m i n e o p e r at e s au t o c lav es f o r r e fr ac t o ry o r e s , b u t t h e l o ca l o r eb o d yd o es n o t co n t a i n en o u g h s u l p h i d e f o r th e au t o c l aves t o b e au t o g en eo u s l y h ea ted . H o m es t ak e n eed ed t osource pyr i te and ended up us ing su lph ide ta l l ings f rom an o ld go ld mine . These ta i l ings a l so con ta inedu n r eco v e r ed g o l d f r o m t h e p r ev i o u s o p e r a t io n w h i ch a s s ay ed 0 .2 4 o z / t o n , co n s i d e r ab l y b e t t e r t h an t h em i n e ' s au t o c lav e f eed o f 0 .1 7 o z / t o n . H o m es t ak e w as ab l e t o p u r ch as e t h e t a i li n g s a t $ 5 0 p e r t o n an dr eco v e r g o l d t o t h e v a l u e o f $ 1 0 0 f r o m each t o n o f t a il i n g s, i n ad d i t io n t o av o i d i n g t h e co s t s o f s t eamgenera t ion fo r the au toclave . Bar r ick has s imi lar ly purchased py r i te ta i l ings f rom a carbon- in -pu lp f ac i l i tyopera ted by Sono ra Gold in Nevad a and used i t as f eed fo r i t s au toclave p lan t nor th o f Car l in , Nev ada [31] .

RE F I M E T --Cl ea n i n g o f Ars en i c R i ch Co n cen tra te sT h e C h i l ean co m p an y R E FI M E T , i n co l l ab o ra t i o n w i t h t h e C en t ro d e I n v es t ig ac i o n es M i n e r o M e t a l u r g i co(CIM M ) , has develope d an innovat ive p rocess to c lean ar sen ic- r ich concen t r a tes [32]. The p rocess i s sos u cces s fu l t h a t , i n ad d i t i o n t o p r o cess i n g C h i l ean o r e s , R E FI M E T i m p o r t s co n cen t r a te s f r o m L ep an t o i nthe Ph i l ipp ines and f rom G reece con ta in ing 10 per cen t a r sen ic . A n increas ing p ropor t ion o f the by-prod uct - - a r sen ic t r iox id e- - i s ex por ted a t a p ro f i t to the Uni ted States a t $335 / tonn e . Th is s ti l l l eaves su rp lussupp l ies , how ever , and as ye t no safe so lu t ion to the i r d i sposa l has been found . Th is i s an ar ea o f ongo ingresearch in Chi le [10] .

L i q u i d E f f l u en t sL i q u i d e f f lu en t s f ro m m i n i n g o p e r a ti o n s h av e b eco m e a m a j o r co n ce r n o f p u b l ic g r o u p s , an d t h i s co n ce r nhas t r ans la ted in to increased r egu la t ion o f wate r qual i ty impacts . M uch pub l ic a t ten t ion has focused on theposs ib i l i ty o f cyan ide escape f rom go ld cyan idat ion opera t ions , and severa l innovat ive methods fo rd es t r o y i n g o r r ecy c l i n g cy an i d e h av e b een d ev e l o p ed i n r ecen t y ea r s i n r e sp o n s e t o i n c r ea s ed s c r u t i n y o ft h e w a t e r q u a l i t y i m p ac ts o f l e ach i n g o p e r a ti o n s. A n u m b er o f co m m er c i a l t e ch n o l o g i e s h av e b eend ev e l o p ed f o r t h e d e s tr u c t io n o f cy an id e . I N C O , f o r ex am p l e , h a s co m m er c i a li s ed a p r o ces s w h i ch em p l o y ssu lphur d iox ide and a i r which , in the p resence o f a copper ca ta lys t , p roduces ox id is ing cond i t ions su f fic ien tto des t roy cyan ide [33] . T h is techn ique has been app l ied a t a num ber o f opera t ing s i tes across Nor thAmer ica . Noranda Inc . has developed a s imi lar p rocess and th i s approach i s be ing used a t Noranda ' ss u b s i d i a ry , H em l o G o l d M i n es I n c , G o l d en G i an t M i n e [ 34 ]. H o w ev e r , s o m e u n a t t rac t i v e f ea t ur e s r em a i nin a l l chemical des t ruc t ion sys tems . These inc lude the use o f expens ive r eagen ts which may haveenv i ronm enta l impa cts , r es idual p rec ip i ta ted heavy-meta l cyan ide complexes , and the loss o f cyan idereagen t .In assess ing cyan ide t rea tmen t techn iques fo r a new go ld mine near Wai t i i in New Zea land ' s N or th I s land ,t h e U .S . - b as ed C y p r u s C o p p e r C o m p an y t e s t ed s ev e r a l m e t h o d s o f d e s t r o y i n g cy an i d e s o t h a t t h e p r o ces sw a t e r co u l d b e s a f e l y d i s ch a r g ed t o t h e Wa i t ek au r i e R i v e r . C y p r u s , h o w ev e r , ch o s e a n ew t ech n o l o g y :ac id i f ica t ion , vo la t i sa t ion and r eneu t r a l i sa t ion (AVR ) . Th is techno logy a l lows the com pany to r em ove an dr ecy c l e cy an i d e b e f o r e i t g o es t o t h e t a i li n g s p o n d . N o t o n l y d o es A V R h e l p C y p r u s s o l v e i t s en v ir o n m en t a lp r o b l em s an d f ac i l i t a t e f u t u r e p e r m i t t i n g an d m i n e d ev e l o p m en t , b u t i t a l s o eco n o m i s e s o n t h e u s e o fcyan ide ( an expens ive r eagen t ) and im proves the r ecovery levels o f go ld and s i lver . C yprus has spen t $1m i l l i o n i n d ev e l o p in g A V R ; i t h a s p a t en t ap p l ica t io n s p en d i n g an d i s ag g r e s s i v e l y s eek i n g t o co m m er c i a l i s ethe techno logy to he lp r ecoup i t s R&D cos ts [10 , 35] .

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Improving environmental performance hrough innovation 919Hom es take M in ing Com pany has a l so tu rned regu la to ry p ressure to clean up a cyan ide seepage p rob lemto i ts advantage. I ts ow n R& D sta ff develop ed a proprietary b iological technique to treat the effluent w hichled to the fast recovery o f local f isheries and w ater qual ity in the mine 's vicini ty at Lead in South D akota.This process is now l t)eing com mercial ised in other operat ions [10]. CA NM ET has com pleted a mult i -yearprogra m to invest igate the chem istry, generat ion and t reatment of thiosal ts in process effluents . M uch o fthis work was done in col laborat ion with the Noranda Technology Centre and i ts f indings have providedimportant informaticm for the developm ent of possible control methods. Oxidat ion with hydroge n peroxidecatalysed by ferrous i ron appeared to be most acceptable but i t was recognised that a bio-oxidat ion proce ssmight be econom ical ly mo re at tractive, al though no methods w ere found to meet the performance and costl imitations need ed by industry [36, 37]. T he problem o f delayed acid generat ion caused by thiosal ts ineffluents rem ains a concern, and current ly forms a part of CA NM ET 's long term research plans.

C O N C L U S I O N SThe mining industry is not general ly regarded as a high technology sector. Nonetheless , manydevelopm ents in advanced tech nology, such as information systems, data processing, and biotechn ologyare revolut ionis ing ]rdning by improving p rocess efficiency and improving the capaci ty o f com panies toachieve and sustain best-pract ice environmental man agem ent . M arket and environmental pressures arepro vidin g a rene we d incentive f or many companies to innovate and /or acquire and assimilate newtechnologies and raanagement practices as a means of improv ing comp eti t iveness and achievingenvironme ntal best-pract ice. There has been a shift within the mo re dynamic com panies aw ay from short-term inve stment in end-of-pipe control technologies towards pol lut ion prevent ion through sou rce reduct ion.Recent research into implicit and explicit corporate technology strategies towards smelting and leachingprocess es suggest that some companies ma y be assessing the capaci ty of the process to meet current andfuture environmen tal s tandards in their development and acquis it ion of alternat ive processing techniques.The rap id and extensive l iberalisat ion of econom ic act ivi ty in many countries over the las t f ive years hasencouraged an inflow of foreign investment which may provide an effect ive vehicle for the t ransfer ofpol lut ion preven t ion technolog y and best-pract ice management techniques. Since 1989 ove r seventy-fivecountries have l iberal ised their investment regimes for mining. New , clean technological developm ents areespecial ly at tractive to governme nts in developing countries s ince they hold the promise o f reducingenvironm ental dam age costs while at the same t ime maintaining the social and econom ic benefi ts of mining(e.g. jobs, taxes , toreign exchange earnings, skil l and technology transfer, royal ty paym ents) . T heopportun i t ies for technological leapfrogging through the t ransfer of innovative produc t ion techniques arerapidly expanding as many less developed countries encourage large explorat ion programmes and designnew m ining laws while es tabl ishing codes of environmental pract ice. As the mining industry enters a newphas e of globalisatkpn, facilitated by econ om ic deregulation and the privatisation of form erly state-o wn edmining concern s, m ining companies and equipment suppl iers are forming a range of joint-ven tureagreements with remaining state-ow ned and new ly privatised operations. N ew investment and strategicpartnering prov ide an opportun i ty for technology t ie-ins in which recipient companies use external lyacqu ired techn olog y to levera ge technological and organisational innovation for their com petitive advantage.Greenfield investm ent prov ides an opportuni ty to select s tate-of-the-art processing techno logies from theoutse t and integrate', new pr odu ction methods with pollution pre ven tion techniques and environmentalmanagem ent system s to achieve low er cost and environmentally proficient produ ction. S trategic allianceswith an environmenl:ally proficient com pany using state-of-the-art techn olog y could be a route to achievinga sou nd environmental track reco rd to enhance investment opportunities.This paper ha s arg~aed that the abi l ity to improve com peti t iveness and environmental perform ance isstron gly influenced b y the capa city of a com pan y to effe ct and sustain technological and organisationalchan ge in resp onse 1:o changing regu latory and marke t pressu res. Th e importance of managerial cap abilityto the successful diffusion of best pract ice techniques is especial ly relevant in the context o f new m ineraldevelop men ts in new ly l iberalising econom ies. Investment in environmental control technology or cleanerproduction techniq~tes is, by itself, an insufficient condition for achieving and sustaining best practiceenviro nm ental man~Lgement. The acquisition, assimilation, and ope ration of innov ative pro duc tion pro ces ses

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9 2 0 A. W arhurst and G. B ridgein an efficient and clean manner is dependent on the capaci ty of management to understand, adapt , andmaster the process , and not solely on the technical specificat ions of plant and equipment . Innovat ivetechnological hardw are do es not by i tself ensure a high level of environmental perform ance, and effortsto achie ve environmental best-pra ctice nee d to address the buildin g of managerial capa city in environmentalmanagem ent along side the deve lopm ent of innovative technologies. Fu ture busin ess research in this areawill therefo re need to address the role of strategic alliances and techno logy transfer agreem ents in enablingcompanies to assimilate new technology and acquire innovative capacity to achieve both low cost,com peti t ive product ion and best practice environmental management .

A C K N O W L E D G E M E N T SThis paper draws on the reserach activit ies of the M ining and Environmental Research Ne twor k (M ER N),d i rec ted by Professor Alyson Warhurst in the School o f Management , Univers i ty o f Bath . M ER N i s aninternat ional netw ork of centres of excellence in mineral producing co untries throughout the world and wa sestabl ished in 19 91 with the aim o f informing both the s tategy of mining firms and the pol icies ofgovern me nts towards achieving cost-effect ive and rational im provem ents in the environmental managementof mining operat ions. In particular th e paper bui lds on an on-going research project into "Te chno logyTransfer and the Diffusion of Clean Tech nology in the Internat ional M ining Industry" which is supportedby the U.K . Econo mic and Social Research Counci l 's Global Environmental Change P rogram me. GavinBridge is a Research Officer with MERN at the Universi ty of Bath and a post-graduate in Geography atClark Unive rsi ty , Massachuset ts . W e wo uld also l ike to acknow ledge the secretarial assis tance ol D . M il tonand Y. Skjonnemand in the preparat ion of this paper.

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