** Canadian lithium miner's shares jump 14.5 pct in early trading after co said Japan's SoftBank Group Corp will buy up to a 9.9 pct stake

** Shares of the miner up at C$ 1.34 after rising as much as 21 pct

** SoftBank to invest up to C$99.1 million ($77.7 million) through a private placement as part of the agreement, Nemaska said on Thursday

** Investment crucial since lithium batteries increasingly installed in electric cars, including Tesla's Model X

** Trade volumes currently at 2.3x 30-DMA on the Toronto Stock Exchange; stock down 12 pct this year

** Sources say co also in talks with U.S. private equity firm Orion Mine Finance Group on a lithium streaming deal (Reporting by Ahmed Farhatha)