Bitcoin (BTC-USD) miner Riot Platforms (NASDAQ:RIOT) is continuing its effort against rival Bitfarms (NASDAQ:BITF), buying more stock and seeking a shareholder meeting to nominate its own directors.Bitfarms, based in Toronto, has rejected Riot’s $950 million takeover bid and is expanding its U.S. operations into Pennsylvania.Meanwhile, speculators pushed BITF stock price to $3.03 per share overnight, the market capitalization rising to $1.25 billion. RIOT stock was due to open at $11.05, a market cap of $3. ...