Draft General Guidelines and Criteria for mining operations in Papua New Guinea (PNG) involving Deep Sea Tailings Placement (DSTP)

Transcription

1 Append x10 Dr af tgu del nesf ordeepseat a l ngspl ac ement Pr oj ec tnumber :8. ACP. PNG. 18B/15

2 Draft General Gudelnes and Crtera for mnng operatons n Papua New Gunea (PNG) nvolvng Deep Sea Talngs Placement (DSTP) 1. Preamble Best Practce Regulatory framework Envronmental Consderatons Draft Gudelnes Feasblty Studes and Intal Mne Development Prelmnary ste evaluaton Envronmental Baselne Mnng Operatons Future Mne Closure Plans Post Mnng Montorng

3 Draft General Gudelnes and Crtera for mnng operatons n Papua New Gunea (PNG) nvolvng Deep Sea Talngs Placement (DSTP) 1. Preamble There s a contnung global need for mneral resources but envronmental ssues assocated wth ther extracton are recevng greater attenton throughout the world. Mnng s an mportant economc sector n PNG and t s essental for human communtes, the envronment and the mnng sector that the best mnng practces and technologes are developed and adopted. Mnng produces large volumes of waste, whch ncludes overburden, waste rock and talngs. There are a number of dfferent methods n whch talngs have been managed throughout the world. These nclude backfllng of mne pts, use of talngs ponds, dry storage of talngs paste, rver dscharge (whch ultmately deposts wastes n the coastal sea), placement of talngs n shallow marne envronments and fnally the placement of talngs n the deep sea (DSTP). The followng draft gudelnes pertan to the practce of placng mne talngs n the deep sea. If mplemented they wll reduce envronmental rsk. The decson as to whether the use of DSTP s deemed acceptable should be based on a good understandng of the relevant envronmental and socal systems affected, but ths s ultmately a poltcal decson made by the government. These gudelnes provde detal for ssues specfcally related to the DSTP process but all other aspects of a proposed development must also be addressed ncludng processes that affect the shallow water envronment such as surface water treatment and dsposal, dsposal of waste rock and mpacts on the ntertdal and shallow sub-tdal envronment from constructon, operaton and decommssonng. These gudelnes are general gudelnes and a set of specfc gudelnes are requred for each ste beng consdered for DSTP takng nto account local socal and envronmental condtons. These ste-specfc gudelnes should be consstent wth exstng PNG legslaton and regulatons. 2. Best Practce 2.1. Regulatory framework Fundamental requrements to ensure DSTP s mplemented to nternatonal best practce are; State of the Art legslaton Competent regulatory authortes wth approprate fundng mechansms to ensure regulatory complance montorng both n terms of the dscharge qualty and ts envronmental effects. Specfc operatonal regulatons for the operaton and mantenance of the talngs placement system 2

4 Standardsed methods for assessment of rsk assocated wth the talngs placement system Establshment of a transparent EIA process where the envronmental protecton outcomes and the most hazardous aspects of the talngs placement actvty are dentfed and approprate mtgaton measures are dentfed; and where the nterests of all stakeholders are dentfed and consdered. A permttng/lcensng process that detals the ste specfc requrements that are needed to protect the marne envronment and acheve the dentfed envronmental protecton outcomes n terms of the dscharge system specfcaton and operaton, and whch ncludes approprate envronmental montorng nformed by the dentfed protecton outcomes and the rsk analyss. Scentfcally robust and transparent methodology for settng sedment and water column Envronmental Qualty Standards (EQS) for potentally ecotoxc dscharge components. A clear process for revewng all the nformaton gathered through the EIA process, showng how ths has been assessed n comng to a decson, and confrmng that all requred procedures have been followed must be mplemented Envronmental Consderatons for DSTP A permttng process s necessary, wth permts detalng ste-specfc requrements ncludng mtgaton measures dentfed by the EIA. The target area for ultmate storage of the talngs should not be of hgh conservaton and/or soco-poltcal value and the envronmental condtons of the area should be such that maxmum deposton of talngs occurs, the physcal envronment ensures adequate flushng to dsperse contamnants n the upper water column, does not experence upwellng of talngs and there s a low probablty of post-depostonal redstrbuton of talngs where t could negatvely mpact areas dentfed for envronmental protecton. The gradent of the path to the target area must be such that a coherent densty current s formed to mnmse dsperson to surroundng areas and any accumulaton near the dscharge. The delvery of talngs to the target area must be suffcently deep to ensure no entranment or advecton of talngs nto the euphotc zone, mnmal producton of plumes due to densty dfferences n the water column, there s suffcently small dffuson of dssolved toxc materal nto the euphotc zone The EIA and ts resultant Envronmental statement should nclude the ssues that are normally requred for marne developments ncludng approprate envronmental baselne, socal, economc and human health ssues. An assessment of the bomagnfcaton of contamnants wthn the food chan should be made. Mtgaton optons for all potental mpacts should be fully evaluated. 3

5 Constructon, operatonal, decommssonng and post-decommssonng aspects should be comprehensvely addressed. 3. Draft Gudelnes In the context of nternatonal best practce, the general gudelnes for the use of DSTP n PNG should consder an examnaton of; 1. Feasblty studes/ ntal mne plannng and development, 2. Mnng operatons, ncludng montorng, 3. Future mne closure plans and 4. Post mnng montorng. The man am of the gudelnes should be to mnmse the mpact on the marne envronment ncludng bodversty, socal, economc, cultural and human health ssues. The potental envronmental rsks to be consdered should nclude; Assessment of the potental toxcty of the talngs,.e. they should be stable and where ecotoxc components are present they should be reduced to concentratons below envronmental qualty standards (EQS), Assessment of the dffuson and dsperson of any dssolved potentally toxc materals n the water column Assessment of mpact on seabed e.g. ncreased sedment accumulaton, change n gran sze, Assessment of mpact on the pelagc zone durng the producton perod e.g. ncreased turbdty and transfer of toxc components to the pelagc food web Assessment of mpact on bodversty durng producton perod e.g. bural, dluton of natural organc carbon nput, boavalablty of toxns, bomagnfcaton, and boaccumulaton, Influence on marne resources e.g. fsheres, Influence on vulnerable ecosystems ncludng culturally mportant habtats, Impact of techncal falure e.g. ppelne fractures, Potental redstrbuton of talngs e.g. producton of under water sldes of deposted talngs, formaton of plumes wthn the water column. All analytcal data collected from envronmental baselne studes, operatonal montorng and post closure montorng must be qualty assured to audtable standards and deposted n a database managed by the competent government authorty. A competent government authorty or a desgnated thrd-party expert revewer must revew the data to ensure that the performance s consstent wth the EIA protecton outcomes and that no sgnfcant envronmental mpacts are emergng. The database wll need to be managed n such away that confdental market nformaton s restrcted and remans confdental. Typcally ths s done by usng an agreed set length of tme after whch data can be made publcly avalable. 4

6 3.1. Feasblty Studes and Intal Mne Development Each development should be assessed wth regards to; Pror experence ganed from all prevous talngs placement systems, both currently operatng and closed systems. Latest scentfc and engneerng knowledge, Apprasal of socetal benefts, mpacts of human communtes, rsks to human health and envronmental mpact of all practcal waste management optons, o DSTP o On land storage, talngs ponds o No talngs e.g. no mne Crtcal factors regardng dsposal of talngs utlsng DSTP, Properly desgned outfall system e.g. durablty and length/depth of ppe Locaton of the outfall to utlse natural topography to mnmse the talngs dsperson and deposton footprnt. A duplcate ppelne should be consdered to allow mne operatons to contnue durng tmes of ppe nspecton or techncal falure, where ths s not mplemented then an entre ppe replacement unt must be kept on ste for mmedate use n case of falure of the ppelne. The safety of the ppelne must be assessed, e.g. to determne the physcal rsks to the offshore ppelne from wave acton, sesmc actvty, or other stresses. Ensurng the correct densty range of the dscharge to mnmse suspended partculate plumes and maxmse placement on the deep sea bed, consderng the followng, Understandng of partcle sze and settlng behavour - n some cases the use of flocculants may be consdered The temperature of the talngs slurry Rato between solds, freshwater and seawater n the ppelne, De-aeraton of the system Prelmnary ste evaluaton 1) Each ste should be consdered on a case by case approach,.e. the evaluaton must be ste specfc. 2) A full evaluaton of all waste management optons must be carred out to ascertan whether DSTP s the BEST opton for dealng wth talngs waste. The envronmental mpact statement (EIS) and supportng studes should compare DSTP wth other land based optons to ascertan the relatve envronmental and socal mpacts/rsks from DSTP and other talngs dsposal optons. 3) Ths process should nvolve all avalable data on every one of the optons beng consdered. If suffcent data are not avalable then further research (scentfc and engneerng) should be carred out before a decson on the 5

7 best waste management opton s made. In partcular a ste specfc study should be made of the proposed recevng waters to determne: ) flushng characterstcs (ncludng upwellng), ) sze of any tdally nduced mxng zone; ) vertcal mxng; v) vertcal plankton mgraton zone, v) horzontal dsperson, v) and depth of the euphotc zone. 4) The data, hstorcal and current, should be made avalable from a database managed by the competent government authorty or ther desgnated thrdparty revewer. 5) After careful scrutny of the exstng data f DSTP s the best avalable opton and s deemed acceptable, then a detaled envronmental baselne of the ste should be carred out as part of the talngs management alternatves analyss. 6) The locaton of the ste should be chosen to, a. be close to the coastlne and have safe overland transport b. have suffcent depth of water and gradent to acheve a coherent gravty flow. c. have suffcently hgh flushng characterstcs to ensure no local buld up of conservatve potentally toxc materals and d. avod locatons of envronmental, socal or economc sgnfcance. 7) The constructon of the DSTP ppelne must be robust and the length of the ppe should ensure that the dscharge s a. at a mnmum depth of 120 m where the maxmum depth of the euphotc zone s 80 m or less, b. where the euphotc zone s deeper than 80m the dscharge should be below the maxmum observed depths of the surface mxed layer or the euphotc zone, whchever s deepest, + 50% of that length, c. formaton of plumes of talngs n the water column must be mnmsed. In the event of densty changes n the water column occurrng the length of the ppe should enable the dscharge of talngs to occur below low-densty weakly stratfed surface waters as detaled n the ste specfc hydrographc measurements. 8) There should be no potental to adversely mpact on rare or valuable ecosystems dentfed n the EIA. 9) There should be no potental to adversely affect natural boresources longterm. It s recognsed that there wll be unavodable adverse mpacts to benthos from a DSTP system. However consderaton must be gven to the sgnfcance and reversblty of any potental mpacts. 10) The prospectve area of talngs deposton must have suffcent volumetrc storage capacty to receve the entre volume of talngs over the lfe tme of the mne. 6

8 11) Coastal nstallatons, ppelnes and mxng tanks must be desgned and constructed wth approprate safety factors to wthstand storm damage, nclude the range of El Nño / Southern Oscllaton (ENSO) varablty. For mnes wth a predcted long lfe, forecasts from a reputable clmate model (where avalable) should be used to determne the lkelhood of storm ncrease/decrease due to clmate change Envronmental Baselne Research and montorng objectves need to be defned by the approprate specalsts (scentsts and engneers). 1) Samplng of sedment, water column, suspended partculate materal and benthc and pelagc communtes must be carred out usng nternatonally recognsed and valdated methods and samplng gear and must be statstcally vald. It s recognsed that for some components such as mega benthos and pelagc fsh t may be dffcult to obtan the number of samples requred to be statstcally vald, however every effort should be made to obtan the necessary sample sze. 2) A valdated numercal modellng nvestgaton of talngs flow, dsperson and deposton must be made. 3) An assessment should be made of the stablty of talngs and lkelhood of re-dsperson through slumpng, densty gradents and current flow. It s recognsed that slumpng of sedment on steep slopes s a natural process, however the addton of talngs wll greatly ncrease the natural rate of sedment accumulaton and may lead to slope falures. In these cases t s mportant to understand the mpact of remoblsaton of prevously deposted talngs. 4) Smple box models of the physcal envronment, usng observed or realstc flushng and exchange parameters, should be produced to determne a budget for the long term dstrbuton of fne scale talngs and any assocated dssolved toxc consttuents. 5) The envronmental baselne should nclude the measurement of; a. The physcal oceanographc envronment (hydrography), near and far feld, whch should be measured for the mnmum of 1 year to determne seasonal varatons n mxng and flushng. b. The dstrbuton of the depth of the weakly stratfed surface layer, montored for the mnmum of 1 year to determne seasonal varatons. c. Geochemcal charactersaton of the area, ncludng, mneralogy, partcle sze dstrbuton, total organc carbon, bogeochemcal cyclng 7

9 of trace elements, flux of trace elements across the benthc water nterface s requred. Ths must be done usng accepted methods of samplng and analyss and must be to an nternatonally accepted level of qualty assurance. d. Sedment accumulaton and mxng rates of the area of lkely mpact and control stes should be measured. In addton areas of eroson and sedment deposton should be dentfed. e. The benthc communty should be enumerated and charactersed usng samplng technques approprate to the three major organsm body sze classes (meofauna, macrofauna and mega fauna). In the absence of unversally accepted dstncton between meo- and macrofauna, the method used to dstngush them (e.g. seve mesh sze or taxonomc dentty) should be clearly stated and consstently appled. Protocols for sample qualty control, level of replcaton, preservaton and laboratory processng should be rgorous and suffcent to meet standards requred for publcaton n the modern peer-revewed deep-sea lterature. 6) An assessment of the degree of benthc pelagc couplng should be made to allow future modellng of possble boaccumulaton and bomagnfcaton of contamnants. 7) Samples of sedment and benthc bota should be collected, preserved and archved before start-up of the mne to provde a sute of pre mnng reference samples at statons predcted to be mpacted and also at reference statons that wll not be mpacted to control for natural varablty over tme. 8) Leachng experments wth talngs should be conducted to ascertan the level of heavy metals, and other potentally toxc components and exchange between the sedment/water column systems. 9) The results from the envronmental baselne should be used to test and reeducate the box models. There must be a strong feedback between the montorng of mpact and the earler determnaton of mpact both to mprove the models and to modfy the montorng n the lght of real nformaton. 10) All data obtaned from the envronmental baselne, ncludng calbraton data, should be ndependently peer assessed by nternatonally recognsed ndependent scentsts and engneers and then deposted n a central database mantaned by the competent government authorty or ther desgnated thrd party revewers. (Independent beng defned as approprately sklled persons that are not ncluded n the montorng and analyss, desgn and operaton of the talngs placement system). 8

10 The database should be managed n such away that market-senstve nformaton s restrcted and remans confdental. Typcally ths s done by usng an tme-lmted embargo after whch data wll be made publcly avalable. The fnancng of an ndependent revew needs to be consdered but should be fnanced va the relevant department, possbly by a levy obtaned from granted lcences. Ths should be admnstered by an ndependent steerng commttee Mnng Operatons The gudelnes relevant to mnng operatons wll be ste specfc. The degree to whch these gudelnes are appled wll depend on the rsk analyss and the predctons made of potental mpacts durng the early stages of the EIA process. For example, the frequency of montorng, numbers of statons, types and number of samples collected and measurements made wll be nformed by the EIA and rsk analyss. There must be feedback from the montorng that wll nfluence the future montorng desgn and ntensty and should be reflected n subsequent operatng permt renewal requrements. The general gudelnes relevant to mnng operatons should contan the followng, 1) Assessment and valdaton of the outfall performance should be made, e.g. fluoromertrc dye experment to provde nformaton on plume formaton and dluton wthn and at the boundary of the mxng zone. 2) Montorng programmes to assess system performance and mpact on the seabed n terms of geochemcal and benthc change should be carred out. Pelagc measurements of zooplankton and nekton abundance and dversty should be made to ascertan any change over the lfetme of the mne operaton. 3) Montorng of physcal, chemcal and bologcal condtons of marne system (.e. sedment and water column) s requred, to ensure that Envronmental Qualty Standards (EQS) for both water and suspended partculate materal are not exceeded outsde a mxng zone agreed n the dscharge permt. Internatonally accepted samplng and analyss methods must be used. 4) Charactersaton and behavour of talngs to be dsposed, ncludng gran sze dstrbuton, chemcal composton and settlng behavour must be assessed and controlled n real tme to ensure best performance of the talngs gravty flow. 5) An assessment of: a. trace element concentratons wthn the sedment, b. trace element concentratons wthn the water column, c. trace element concentratons wthn suspended partculates, 9

11 d. trace element concentratons wthn benthc bota, e. trace element concentratons wthn zooplankton and nekton should be made. 6) Data need to be of a hgh standard and full QA system should be n place. 7) Results requre to be documented and kept n a central database by the competent government authorty or desgnated thrd party expert revewer. The database should be accessble to all those wth a genune need to access and use the data. The database wll need to be managed n such away that confdental market nformaton s restrcted and remans confdental. Typcally ths s done by usng a set length of tme after whch data can be made publcly avalable. 8) Use of automated systems for detectng falures n ppelne,.e. remote sensors. Such devces should be part of an approved Emergency Response Plan. 9) Automated system for montorng of the marne envronment surroundng the DSTP dscharge ste: ntellgent moorngs delverng real tme data where applcable. 10) Requre ndependent marne scentst to advse on montorng regmes and plans and revew montorng data and reports produced by consultants. The fnancng of ndependent advce needs to be consdered but should be fnanced va the relevant department, possbly by a levy obtaned from granted lcences. Ths should be admnstered by an ndependent steerng commttee. 11) Agreed nternatonally accepted samplng methods, analyss methods, calbraton methods and methods of data nterpretaton should be adopted and mantaned. 12) Rsk assessment and montorng regmes should be lnked. 13) Perodc ground truthng of models and re-calbraton as approprate 14) Preparaton of an Emergency Response Plan 3.3. Future Mne Closure Plans Future mne closure plans are not consdered n the techncal gudelnes for the use of DSTP. 10

12 3.4. Post Mnng Montorng Montorng of the physcal and chemcal characterstcs of the talng sedment deposts and overlyng water column and of the benthc communty should be contnued after mne closure. The gudelnes relevant to post-mnng montorng wll be ste specfc and should contan the followng, 1) The post-mne-closure plan should nclude a plan detalng the envronmental montorng plan whch should be carred out after the closure of the mne. Ths plan should be nformed by the ntal envronmental baselne study and the envronmental montorng undertaken throughout the lfetme of the mne and be updated as necessary. 2) The post-closure envronmental montorng plan should be approved by the competent government authorty wth nput from the apponted ndependent expert revewer. 3) A comprehensve post-closure envronmental study should be carred out to ascertan the envronmental condtons that preval at the tme of mne closure whch should nclude, a. A detaled bathymetrc and sesmc survey of the area potentally mpacted by talngs. b. Geochemcal charactersaton of the area, ncludng, mneralogy, partcle sze dstrbuton, bogeochemcal cyclng of trace elements and the flux of trace elements across the benthc water nterface s requred. Ths must be done usng nternatonally recognsed and accepted methods of samplng and analyss and must be to an nternatonally accepted level of qualty assurance. c. Charactersaton of the benthc communty ncludng, mega, macro and meo fauna and ther recovery dynamcs usng nternatonally recognsed and accepted methods of samplng and analyss and must be to an nternatonally accepted level of qualty assurance. 4) The results from the post closure envronmental study should be used along wth those from regular montorng to assess the rate of recovery of the area mpacted by talngs deposton and to nform any further montorng that may be requred. 5) The frequency and extent of montorng should be nformed by past mnng operatons and envronmental montorng results. 6) All data from the post closure envronmental study and regular envronmental montorng must be qualty assured and deposted n a database that s managed by a competent government authorty or ther desgnated thrd party expert. 11

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