Mine Closure Risk Assessment A living process during the operation

Transcription

1 Tailigs ad Mie Waste 2017 Baff, Alberta, Caada Mie Closure Risk Assessmet A livig process durig the operatio Cristiá Marambio Golder Associates

2 Closure chroology Chilea reality Gov Evirometal basis law Health & Safety Closure law starts to operate 2014 "Trasitio closure pla 2015 to date Geeral applicatio of the law (Risk Aalysis) Coceptual closure Closure measures put ito a documet Let put all closure measures committed to differet authorities ito a sigle documet Closure measures had to be costed. Based o those costs, put a warraty Opportuities to review ad comprehesively defied closure measures Miig Compay Cost Closure is costless Closure measures had to be quatified ad costed. 1st Surprise: there are commitmets that are impracticable or extremely expesive 2d Surprise: I have to cost them ad put a warraty for them. Now the closure measures had to be techically approved by the authorities. Closure measures defiitio is part of a risk aalysis. Costs are related to the amout of risk that the compaies are willig to have.

3 Presetatio outlie Itroductio Closure risk assessmet Operatioal data related to closure Ucertaity at closure Coclusios Jauary 31,

4 Itroductio Do we really uderstad how facilities will behave after closure? Do we completely kow what are the risks associated to closure ad their cosequeces? Have we cosidered closure aspects/coditios durig desig phases of our projects? Jauary 31,

5 Closure risk assessmet The process where potetial failure modes ad their sigificaces are idetified, based o the combiatio of their probability of occurrece ad their cosequeces. Risks are the geerally formed by three mai compoets: a triggerig evet (i.e. heavy raifall, earthquake, flood), its probability of occurrece (which is related to its magitude), ad its cosequece. Ope pit failure? Tailigs dam failure!!! Jauary 31,

6 Closure risk assessmet But these three compoets are ot idepedet Facility desig criteria Triggerig evet Cosequece Probability of occurrece Jauary 31,

7 Mie operatio ad risk assessmet The idetificatio of the triggerig evets, their quatificatio ad how facilities should respose to those evets, is geerally kow. But, is the uderstadig of how they were costructed ad operated, what really idicates their real state ad ca help i predictig their behavior after extreme evets. If desig criteria were ot met durig costructio or operatio, they may sigificatly uderestimate closure risks ad, therefore uderestimate the eeds for closure measures ad their costs. Part of uderstadig closure behavior ad the real sigificace of closure risks is to have the iformatio ad the date required to project differet evets to a post closure sceario. Jauary 31,

8 Operatioal data related to closure A great deal of iformatio measured ad stored durig the operatio of mies ca be useful for closure risk assessmet, providig the evaluatio team with solid data to support projectios over the log term. But data maagemet is a key challege. Operatioal iformatio may exist i servers, but distributed over may folders ad years of operatios, ad operators may chage or leave mies (especially as it approaches closure), resultig i a loss of cotiuity ad access to the iformatio. Or it may simply have bee ever collected or properly stored i the first place Jauary 31,

9 Ucertaity at closure Misuderstadig of the potetial risks ca lead to makig wrog decisios based o over or uder-valuig the cosequeces ad probabilities. Misuderstadig variables ivolved i closure could lead to ot idetifyig ad evaluatig relevat risks scearios, with potetial serious cosequeces. Miimizig ucertaity to the degree possible is closure goal for proper data collectio ad maagemet durig operatio. Jauary 31,

10 Ucertaity at closure Miimizig ucertaities ot oly helps cotrollig risks, but it also helps cotrollig costs as closure provisios ca be better dimesioed. Ucertaity ca produce sigificat costs overrus durig closure, as ew closure measures eed to be desig ad implemeted or the cosequeces of uwated evets rehabilitated. I some jurisdictios, sites are ot trasferred to the regulatory authority util a complete rehabilitatio is achieved. Adequate dimesioig of the post closure period is eeded to develop a accurate estimate of costs for post closure. Jauary 31,

11 Good quality operatioal iformatio ca provide the eeded data for better estimates of post closure requiremets. Jauary 31,

12 Ucertaity at closure Reduced closure ucertaity also provides beefits for the relatioship with commuities ad stakeholders. Reducig closure ucertaity ad demostratig that the risks iheret to mie closure are cotrolled, well dimesioed ad well maaged, is very importat for gaiig commuity support ad acceptace of both miig projects ad their evetual closure. Maagig closure as a livig process durig the operatio provides beefits for reduced ucertaity i closure ad log term plaig, as well as for the relatioship betwee miig compaies ad stakeholders. Jauary 31,

13 Coclusios Uderstadig mie behavior after closure is a key factor i determiig the actios ad closure measures required to achieve effective closure solutios. Desig criteria are ofte available, but they oly represet how facilities where plaed. Their costructio ad operatio is what really cotrols their behavior i the log term. As costructio ad operatio of mie facilities typically bridges may years, a disaggregated source of relevat data if ofte geerated. Kowig which types of iformatio are relevat for closure eeds, ad keepig orgaized records ca be critical for the closure risk evaluatio. Jauary 31,

14 Coclusios Closure plaig ad evaluatio has to be uderstood as a activity that has to be developed i close aligmet with how facilities were plaed, costructed ad operated with relatively few surprises (if possible). The, it ca be uderstood as: A process that starts with the facilities desig ad cotiues through its costructio ad operatio; A process that is plaed ad uderstood as a cotiuatio of the operatioal life; A process that is typically goig to be defied ad carried out by professioals who were ot ivolved i its desig, costructio ad operatio; A process that eeds to achieve a certai level of accuracy, as it is ivolved i the compay s fiaces (closure provisios) ad legacy (stakeholder s opiio), as well as cotiued social licese for operatio. Jauary 31,

15 Thak you. Jauary 31,