▁Kre ug er ' s ▁business ▁emp ire ▁until ▁ 1 9 3 2 . ▁The ▁R ön n sk är ▁sm elter ▁was ▁built ▁to ▁process ▁the ▁Bol iden ▁ore , ▁and ▁comm enced ▁sm el ting ▁operations ▁in ▁ 1 9 3 0 . ▁The ▁world ' s ▁longest ▁ore ▁tram way , ▁between ▁Bol iden ' s ▁mine ▁in ▁Krist ine berg ▁and ▁Bol iden ▁became ▁oper ational ▁in ▁ 1 9 4 3 . ▁The ▁ore ▁tram way ▁was ▁ 9 6   km ▁long ▁and ▁by ▁the ▁time ▁it ▁was ▁shut ▁down , ▁ 4 4 ▁years ▁later , ▁it ▁had ▁transport ed ▁ 1 2 ▁million ▁t onnes ▁of ▁concent rate . ▁Oper ations ▁started ▁at ▁the ▁A it ik ▁mine , ▁outside ▁G äll iv are , ▁in ▁ 1 9 6 8 . ▁This ▁open ▁pit ▁mine ▁would ▁develop , ▁over ▁the ▁years , ▁into ▁one ▁of ▁Europe ' s ▁biggest ▁co pper ▁mines . ▁During ▁its ▁first ▁year ▁of ▁operations , ▁it ▁produced ▁approximately ▁ 9 , 0 0 0 ▁t onnes ▁of ▁co pper , ▁ 1 6 0   kg ▁of ▁gold ▁and ▁ 7 ▁t onnes ▁of ▁silver . ▁ ▁The ▁company ▁grew ▁during ▁the ▁first ▁few ▁years ▁of ▁the ▁ 1 9 7 0 s ▁thanks ▁to ▁a ▁joint ▁vent ure ▁with ▁the ▁German ▁company , ▁Pre uss ag . ▁This ▁led ▁to ▁the ▁expansion ▁of ▁Bol iden ' s ▁lead ▁sm el ting ▁and ▁ref ining ▁capacity , ▁and