b'(X US$ 1,000) Decommissioning productionDecommissioning Decommissioning Environmental Other Totalfield & facilities Refinery Power Plant Risk ProvisionsAt January 1, 2018 79,422 8,884 209 2,781 1,758 93,054Arising during the year7- - -1,126 1,133Write-backofunusedprovisions- - - - - - Discountrateadjustment&imputedinterest (31,251) (2,959) (107) 48-(34,269)Unwindingofdiscount 6,658 744 17 167-7,586Utilisation- - - -(66) (66)At December 31, 201854,836 6,669 119 2,996 2,818 67,438 Arising during the year - - - -80 80Discountrateadjustment&imputedinterest 54,956 3,768141 - -58,865Unwindingofdiscount 5,635 6751268-6,390Translationadjustment- - -(6)-(6)Utilisation- - - -(625) (625)At December 31, 2019115,427 11,112 272 3,058 2,273 132,142 Comprising:CurrentatDecember31,2018- - - - - - Non-currentatDecember31,2018 54,836 6,669 119 2,996 2,818 67,438 54,836 6,669 119 2,996 2,818 67,438 Comprising:CurrentatDecember31,2019- - - - - - Non-currentatDecember31,2019 115,427 11,112 272 3,058 2,273 132,142 115,427 11,112 272 3,058 2,273 132,142 toestimatethefutureliability.Theseestimates stationsand3oilterminals.Thesesiteswillbearereviewedregularlytoconsideranymaterial remediatedinanine-yeartimeframe.Thepresentchangestotheassumptions.However,actual valueoftheestimatedcostsasatDecember31,decommissioningcostswillultimatelydepend 2019isUS$3,058(asatDecember31,2018upon future market prices for the necessaryisUS$2,996).Theamountrecognizedisthedecommissioningworksrequiredthatwill best estimate calculated by management of the reflectmarketconditionsattherelevanttime. expenditurerequired.Furthermore,thetimingofdecommissioningislikelytodependonwhenthefieldsceaseto Other provisionsproduceateconomicallyviablerates.This,inturn, AprovisionatfairvalueofUS$2,273atwilldependuponfutureoilandgasprices,which December31,2019(US$2,818asofDecemberare inherently uncertain. 31,2018)mainlycompriseprovisionsforlitigationThediscountrateusedinthecalculationofthe orcontractualclaims.TheclaimsaresubjecttoprovisionasatDecember31,2019is7.82%(2018: legalarbitrationandarenotexpectedtofinalize10.28%). during 2020. Environmental risk provisionGOw2purchasedChevronin2011whichincludedtheirmarketingactivitiesinSurinameof22petrol91'