Glencore Plc said on Monday it had proposed to buy the remaining stake in copper miner PolyMet Mining it does not already own for about $71 million.
The Swiss commodity trader already owns 82.26% of PolyMet.
Glencore is in the midst of a bigger acquisition bid for Canada's Teck Resources as the miner looks to increase exposure to energy transition metals such as copper and nickel.
Glencore's non-binding cash offer of $2.11 per share values PolyMet at about $410 million, according to Reuters calculation.
Shares of PolyMet more than doubled in premarket trading to $1.87.
(Reporting by Tanay Dhumal in Bengaluru; Editing by Shilpi Majumdar)
