A Water Accounting Framework for the Minerals Industry

Transcription

1 A Water Accunting Framewrk fr the Minerals Industry Minerals Cuncil f Australia April 2010 Cntact & Further Infrmatin: inf@wateraccunting.net.au Minerals Cuncil f Australia

2 Overview The minerals industry water accunting framewrk is funded in a cncept mdel that relates an peratinal facility s water interactins with the surrunding envirnment and cmmunity (Figure 1). The cncept mdel at this level is cmprised f fur functinal elements: (1) (2) (3) (4) Input, representing the receipt f water t the peratinal facility; Divert, mving water arund r thrugh the peratinal facility; Task-treat-stre cycle, representing the peratinal tasks assciated with minimising lsses, managing climate variability and implementing efficient technlgies and prcesses; and Output, representing the remval f water frm the peratinal facility. Figure 1. Water system cncept mdel fr accunting purpses (DRET 2008) Fr water accunting purpses, there are three key areas requiring attentin: The intersectin f the facility with the surrunding envirnment, cmmunity and ther stakehlders; this addresses cmmn questins such as where des the water cme frm, hw much water cmes frm where, and where des the water g?. This area has been labelled the Input-Output Mdel and it cnstitutes the fundamental cmpnent f the water accunting framewrk. Activities and uses f water internal t the peratin, which describe the typical actins that water is subjected t whilst in cntrl f the minerals peratin. This includes activities such as peratinal tasks (e.g. dewatering re bdies, prcessing re), water quality treatment (e.g. cyanide destructin, physical settling), and string f water. It addresses cmmn questins such as hw much water d yu recycle, hw much water d yu reuse, hw efficiently d yu use water and d yu use water as efficiently as ther nearby users? This area has been labelled the Operatinal Mdel. The quality f the inputs and utputs; this addresses cmmn questins such as what quality f water enters r leaves the site and hw did an peratin transfrm water quality? This area has been labelled Water Quality Descriptin. 2

3 The cmbinatin f these three areas is the Minerals Industry Water Accunting Framewrk 1. The areas have been separated t prvide guidance fr cmpanies at several levels; the Input-Output Mdel prvides the basis fr a water accunting framewrk, and the Operatinal Mdel and the Water Quality Reprting prvide guidance fr cmpanies that see greater value in applying these tw appraches. The standard accunting perid is ne year but the framewrk can be applied at shrter r lnger intervals if required. Each area is discussed in detail with examples fr each cmpnent in Appendix 1. The framewrk has been designed t be as flexible as pssible, enabling individual cmpanies r peratins t determine their accunting needs based n their requirements. The Input-Output Mdel is a fundamental cmpnent f the Minerals Industry Water Accunting Framewrk, with ther elements being incrprated based n specific risks and drivers. Cnsider Materiality, Cntext and Accuracy Acrss all Accunting Effrts Regardless f the level f detail t be included in specific water accunts, and the nature f thse accunts (e.g. including water quality r the Operatinal Mdel), the cncepts f materiality and cntext shuld apply t all accunting effrts. When deriving the quantitative values f any water flws, the cncept f materiality is applied. Infrmatin is material if its missin frm the mdel can influence decisins related t the interpretatin f the water accunt. Fr example, envirnmental water flws may be relatively small in vlume, but may be critical fr maintaining ecsystem health, and therefre infrmatin abut such water flws is relevant t decisin makers and shuld be included in the input-utput mdel. A cntextual statement is an essential part f the water accunting framewrk as it ensures accunts are nt divrced frm the cntext in which a facility is perating. A cntextual statement prvides backgrund infrmatin abut the water resurces f the peratinal facility as well as any cnditins that have an impact n the management f thse water resurces. As a guide they shuld cntain a descriptin f the gegraphical lcatin f the peratinal facility, details f the catchment, climatic cnditins during the reprting perid, infrmatin n water plicy and rules applicable t the peratinal facility, and any administrative change such as changes t a water-sharing plan. The accuracy f accunts is cmmunicated thrugh an accuracy statement, which shws the prprtins f flws (by vlume and / r number), which are measured, estimated r simulated. The level f cnfidence assciated with each flw (lw, medium r high) shuld be prvided in the accuracy statement. Finally, ntes prvide infrmatin abut majr assumptins, hw each element in the accunt was calculated and abut which accunt elements are affected by infrmatin gaps. Issues dealing with cntractual and legal arrangements (e.g. discharge license), third-party arrangements shuld als be listed in the ntes. Remember, the creatin f perfect accunts is nt the verarching gal. The key gals relate t transparency, cntinuus imprvement in water resurce management, cmmunicatin and stakehlder engagement. 1 The framewrk is simply an apprach fr cnsistent cmmunicatin, it des nt prvide tls t generate accunts. Such tls are external t the framewrk, and many peratins have existing tls that can be used t ppulate an accunt. 3

4 The Input-Output Mdel The Input-Output Mdel enables the cnsistent presentatin f accunts and it includes the fllwing key terms: The Operatinal Facility is defined lcally by the peratin (r reprting / accunting entity) based n cnsultatin with stakehlders, and alignment with ther reprting requirements as necessary. It can include the ttal mining lease, r a smaller defined peratinal area. It must be spatially explicit, readily cmmunicated, and sensible. An Input is a vlume f water, which is received by the peratinal facility, r has becme available frm within the peratinal facility [in the case f grundwater which was present befre peratins began, and has been subsequently accessed]. Inputs can be summarised / aggregated by their surces r reprted as a diversin. Surces are the primary accunting descriptin fr inputs, they are described by the pint f water extractin, and include surface water, grundwater, sea water and third party supply. Surface Water: all water naturally pen t the atmsphere, except fr water frm ceans, seas and estuaries. Examples f surface water include: water extracted frm natural water bdies such as rivers, lakes, reservirs, pnds, streams, which is unregulated and un-supplemented; rainfall and runff cllected frm within the peratinal facility, which is regulated r supplemented; precipitatin which is captured directly by water strage facilities; and runff cllected frm utside the peratinal facility, which is regulated r supplemented. Grundwater: water beneath the earth's surface that fills pres r cracks between prus media such as sil, rck, cal, and sand, ften frming aquifers. Fr accunting purpses, water that is entrained in the re can be cnsidered as grundwater. Sea Water: water frm ceans, seas and estuaries. Third-party Supply: water supplied by an entity external t the peratinal facility, usually thrugh a cmmercial arrangement with specific infrastructure fr water delivery. Third-party water cntains water frm the ther three surces and in sme cases, the distributin f surface water, grundwater and sea water is knwn. Hwever, minerals peratins cannt be accuntable fr reprting the surcing f water by third parties. If an peratin facility has a cmmercial arrangement t receive water frm a third-party entity, this water shuld be reprted as third-party water. If a third-party is acting as a facilitatr t access water (e.g. an peratinal facility is being granted access t a grundwater bre by the gvernment r a neighburing farm), the water shuld be reprted as surface water, grundwater r sea water. When there is dubt, the physical surce (surface water, grundwater, sea water) shuld prevail. Diversins include water that is diverted away frm the peratinal facility, and is nt invlved in any f the tasks within the peratinal facility. It is water which is actively managed by the minerals peratin, but is nt used in a traditinal cnsumptive sense. Sme handling lsses can be incurred befre the water is transferred t areas external t the peratinal facility. Examples f diversins include: creek diversins, runff diversins; and aquifer dewatering with either subsequent grundwater reinjectin r transferral t surface water external t the peratinal facility. An Output is a vlume f water, which is remved frm the peratinal facility. 4

5 Destinatins are the primary accunting descriptin fr utputs, they are generally described by the pint f water receipt utside the peratinal facility, and include: Surface Water: all water naturally pen t the atmsphere, except fr water frm ceans, sea and estuaries. Examples f utputs t the surface water destinatin include traditinal discharges t surface waters; and envirnmental flws specifically prvided by the peratins. Grundwater: water beneath the earth's surface that fills pres r cracks between prus media such as sil, rck, cal, and sand, ften frming aquifers. It includes seepage frm the water stres and frm the tailings strage facility. Examples f utputs t the grundwater destinatin include: aquifer reinjectin; and filling clsed extractive peratins utside f the peratinal facility Sea Water: water frm ceans, seas and estuaries. Third-party Supply: water supplied t an entity external t the peratinal facility, usually thrugh a cmmercial arrangement. Evapratin: water released t the atmsphere during strage, handling r applicatin. Entrainment: water remved frm the peratinal facility cntained within prduct r waste streams. The water within the tailings that cannt be recvered, is entrained water. Other: represents a cmbinatin f destinatins and is used when we cannt identify a clear destinatin pathway. It als includes lsses that cannt readily be accunted fr r measured (e.g. lsses frm a prcessing plant). The Input Output Mdel is used t derive a statement f inputs and utputs, supprted by infrmatin that adds cntext t the numbers that are presented. That is the end f the descriptin f the framewrk elements f the Input-Output Mdel. Such a mdel will prvide mst stakehlders with all the water infrmatin they require regarding the minerals peratin, and its intersectin with the envirnment and cmmunity. Water Quality Descriptin Under each Surce and Destinatin categry, entries can be reprted as being f a stated water quality based n their biphysical characteristics that determine whether they are fit fr purpse (defined lcally by the peratin based n cnsultatin with stakehlders) fr alternative uses within the catchment. The apprach t water quality reprting is based n three categries f water: Categry 1 is water clse t the standards f drinking water, as it nly requires minimum treatment (disinfectin) t be safe fr human cnsumptin. It can be used fr all purpses. Categry 2 is water that requires treatment t remve ttal disslved slids and t adjust ther parameters t be safe fr human cnsumptin. It can be used fr many agricultural and recreatinal purpses. Categry 3 is hyper saline water that cannt be used fr any agricultural purpses withut remval f ttal disslved slids. With regards t the inputs f sea water, if it is desalinated befre it is supplied t the peratin, it shuld be reprted as Categry 1 r 2, depending n the perfrmance f the desalinatin prcess. If it is supplied withut remval f disslved slids, it shuld be reprted as Categry 3. The decisin tree in Figure 2 can be used t help assign a water quality categry t the inputs and utputs. 5

6 Figure 2. Selecting a Water Categry fr a Water Input r Output The Operatinal Mdel - Optinal The bjective f the Operatinal Mdel is t prvide a cnsistent framewrk fr quantifying and dcumenting water use within an peratin, including its efficiency. It is als designed t prvide a platfrm fr cmpiling and cmparing minerals industry water use with ther sectrs. This may supprt benchmarking activities within regins r cmpanies. Therefre, t develp the Operatinal Mdel, a cnsistent language is required, fr cmmunicating, within peratins, hw water is managed. In light f the bjectives, in sme instances it has been easiest t adpt cmmnly used terms, in ther instances, it has been decided that the easiest ptin is t develp and define a new term. Activities and uses f water within the peratin describe the typical actins that water is subjected t whilst in cntrl f the minerals peratin. This includes activities such as peratinal tasks (e.g. dewatering re bdies, prcessing re), active water quality treatment (e.g. cyanide destructin; see DRET 2008), and string f water (i.e. usually fr peratinal tasks r influencing water quality). The Operatinal Mdel brings tgether three elements: 1. The Inputs and Outputs; 2. The Task-Treat-Stre cycle utlined in the cncept mdel (Figure 1); and 3. The cncepts f Reuse and Recycling. This is nt a simple thing t d, and has required the develpment f several new terms, t cmmunicate the cncepts f reuse and recycling sensibly. The cncept f water status has been develped fr this purpse. The water status is a descriptin f whether r nt water has been tasked and / r treated after it has entered the peratinal facility as an input. We define: Raw water: water that is received as an input and has nt been previusly tasked fr any purpse by the peratinal facility; Stres are the facilities within the peratinal facility which hld and/r capture water. Water must be stred within s that it is available fr anther applicatin at the apprpriate time; Flws are the physical mvements f water between stres and tasks, these are usually represented in engineering descriptins f water management within peratins; 6

7 Tasks are peratinal activities that utilises water, typically including re extractin, re prcessing, dust suppressin, fire fighting, and amenities uses; Wrked Water: water that has been thrugh a task and is returned t a stre fr the same r anther future task and/r is discharged; and Treated Water: water that has been treated nsite t prvide water f a suitable quality fr a particular purpse. It refers t active treatment f water (see [DRET 2008]) rather than passive treatment. It can include raw water treated nce received n site, r water used in the prcess then treated t allw further use, r even release t an utput destinatin. All water, be it raw, wrked r treated water can be tasked, treated r released as an utput, thus the water status changes as it mves thrugh the Task-Treat-Stre cycle. In the case f raw water which is released as an utput, this is knwn as a diversin. Acceptance f the status definitins enables the cnsistent develpment and applicatin f the cncepts f reuse and recycling. Reused Water is wrked water that is again-tasked withut being treated. Recycled Water is wrked water that has been treated. We can then define the reuse efficiency and recycling efficiency as a prprtin f the ttal water inputs t the tasks: Reuse Efficiency = Sum f Wrked Water Flws t Tasks Sum f All Flws t Tasks Recycling Efficiency = Sum f Treated Wrked Water Flws t Tasks Sum f All Flws t Tasks In mst cases, the sum f inputs (what the peratinal facility is drawing frm the surrunding envirnment) will be much less than the sum f all flws t the tasks. In the example prvided in Appendix 1 the sum f inputs is 9,296 ML and the sum f flws t the tasks is 41,522 ML. The Operatinal Mdel is used t derive a statement f peratinal efficiencies. Example A full example accunt, based n a pilt peratinal facility, is prvided in Appendix 1. It cntains the fundamental cmpnent (Input-Output statement with cntextual infrmatin, statement f peratinal efficiencies, accuracy statement) and the ptinal cmpnents (water quality reprting, statement f peratinal efficiencies). Fictinal names and lcatins have been used in the cntextual infrmatin s that the peratinal facility cannt be identified. References & Further Infrmatin Guidelines fr develping water accunts based n the minerals industry water accunting framewrk: Fr water-related infrmatin in Australia: Bibligraphy 7

8 Cte, C. M. and C. J. Mran (2009). A Water Accunting Framewrk fr the Australian Minerals Industry. 4th Internatinal Cnference n Sustainable Develpment Indicatrs in the Minerals Industry. Gld Cast, Australia. Published by the Australasian Institute f Mining and Metallurgy. Publicatin Series N 5/2009: Cte, C. M., C. J. Mran, Ringwd, K., Cummings, J. (2009). Develping a Water Accunting Framewrk fr the Australian Minerals Industry. Water in Mining Perth, Australia. Published by the Australasian Institute f Mining and Metallurgy. Publicatin Series N 8/2009: Cte, C. M., C. J. Mran, Ringwd, K., Cummings, J. (2009). Develping a Water Accunting Framewrk fr the Australian Minerals Industry. MCA Sustainable Develpment Cnference, Adelaide, Octber Department f Resurces, Energy and Turism (DRET), Water Management Leading Practice Sustainable Develpment Prgram fr the Mining Industry. Published by Cmmnwealth f Australia, Canberra. MCA Sustainable Develpment Cnference, September Industry Wrkshp. 8

9 Appendix One Sample Accunt 9

10 1) Cntextual Infrmatin The peratinal facility is the Mining Cmpany, Henry River site. The water system cmprises f: prcessing and mining facilities, twnship supply netwrk, Bggy Creek, Henry River-regulated, and Bggy Creek Alluvium. Third-party water (twnship supply) accunts fr 43.5% f the ttal water surcing activities nsite in the 2007/08 financial year, which is clsely fllwed by the 40.3% surced frm surface water rivers and creeks. Grundwater surced thrugh interceptin and extractin accunts fr apprximately 9.7% f the peratinal facility s water surcing activities. Further surface water resurces surced thrugh direct precipitatin interceptin and runff harvesting reprted fr apprximately 6.4% f the ttal water inputs t site. The majr utputs frm the site were via evapratin, which accunted fr 4202ML (46.6%), and entrainment (3895ML, 43.2%). The remainder was lst via seepage, miscellaneus task lsses and envirnmental flws. The peratinal facility has tw majr stres with maximum hlding capacities f 4,200ML and 3,700ML respectively. Water surcing activities must fllw the rules as set ut in the water sharing plan fr the regulated Henry River as well as thse in the macr grundwater sharing plan fr the Bggy Creek Alluvium. Mrever, Mining Cmpany Henry River site has its wn peratinal management plicies and regulatins aimed at maintaining water supply and minimising discharge risk. The main bdies, besides the peratinal facility itself, with respnsibility fr the management f the water resurces that cnstitute the Mining Cmpany Henry River site water system are: State Water, Department f Water and Energy (DWE), the lcal regin Catchment Management Authrity, and the lcal cuncil frm which third party water is surced. The ttal rainfall fr the reprting perid was 710mm cmpared t the lng term average f 817mm. The average temperature was 13 C which was the same as the lng term average. (Climate data surced frm BM SILO). Entitlement licences are as fllws: General security 4080ML/yr (~0.7% f the ttal general security access available), High security 3125ML/yr (11.8% f the ttal high security access available), Onsite surface water extractin 4200ML/yr (~0.7% f the ttal general security access available), Explratin interceptin 931ML/yr (14.8% f the ttal entitlement fr the Bggy Creek Alluvium), Bre field extractin 371ML/yr (5.9% f the ttal entitlement fr the Bggy Creek Alluvium). Mnthly allcatins are set by the Water Department and water restrictins are as per the rules set ut in the water sharing plan fr the regulated river systems. The cnditins fr extractin frm nsite creeks are as fllws: water is released frm the dam t maintain a flw f 0.4ML/day at the gauging statin. When inflws are between 0.4 and 3.4 ML/day, water is released frm the dam t achieve a flw rate at the gauging statin equal t the inflw int the dam. When inflws are greater than 3.4ML/day, water is released frm the dam t maintain a flw f 3.4ML/day at the gauging statin. Once per quarter a medium flw event is t be achieved at the gauging statin. A medium flw event invlves a flw f greater than 10ML/day fr at least 3 days. Trading activity fr the 2007/08 perid: entitlements were purchased frm land wners n the Henry River catchment. This transfer accunted fr 4.8% f the verall water surcing activities nsite. 10

11 (2) INPUT OUTPUT STATEMENT REPORTING PERIOD 1 ST July 2007 t 30 th June 2008 Input surces and utput destinatins are in bld. Inputs ML Quality Ntes Surface Water Precipitatin and runff 2,535 Categry 1 1 Rivers and Creeks 1,132 Categry 1 2 Grundwater Aquifer interceptin 487 Categry 2 2 Bre fields 354 Categry 1 2 Entrainment 570 Categry 2 3 Sea Water 0 Third party water Twn Effluent 3,800 Categry 1 2 Entitlement transfer 418 Categry 1 2 Ttal Inputs 9,296 Outputs ML Quality Ntes Surface Water Envirnmental flws 319 Categry 1 2 Grundwater Seepage 426 Categry 2 4 Sea Water 0 Supply t Third party 0 Evapratin 4,202 Categry 1 2 Entrainment 3,895 Categry 2 2 Other Task lsses 183 Categry 2 5 Ttal Outputs 9,025 Water Balance Inputs Outputs (ML) 271 Strage at Start (ML) 983 Strage at End (ML) 1,254 Change f strage (ML) 271 Ntes 1. This value is frm the Water Management Plan. We have recalculated it and fund that precipitatin interceptin (particularly frm tailings strage facility) is likely t have been mitted frm the reprted value. We did nt have enugh data t cnfidently calculate precipitatin interceptin. 2. Frm Water Management Plan 3. Lw cnfidence estimate based n prcessing rate f re and an entrainment factr f Calculated t clse the water balance. 5. Task lss includes lsses frm ptable water, undergrund mining Fr ease f reprting, the vlumes that make up the fur surces and seven destinatins are summarised: 11

12 INPUT SUMMARY BY SOURCE & QUALITY (ML/YR) Categry 1 Water Categry 2 Water Surface water 3,667 0 Grund water 354 1,057 Sea water 0 0 Third-party water 4,218 0 OUTPUT SUMMARY BY DESTINATION (ML/YR) Surface water Grund water Sea water 0 0 Third-party water 0 0 Evapratin 4,202 0 Entrainment 0 3,895 Other Change f Strage 271 (3) STATEMENT OF OPERATIONAL EFFICIENCIES Operatinal Efficiencies Ttal flws int Tasks (water required t mine; ML) 41,522 Vlume f reused water (ML) 32,520 Vlume f water inputs t the Operatin (ML) 9,296 Reuse efficiency (%) 78% Vlume f recycled water (ML) 24 Recycling efficiency (%) 0.06% 12

13 (4) ACCURACY STATEMENT By Flw Vlume By Number f Flws Flws Types % f all Flws Level f cnfidence % f all Level f cnfidence High Medium Lw Flws High Medium Lw Measured Estimated Simulated Ttal