Contact Energy (ASX:CEN, NZE:CEN) received notice that Blackrock Advisors and its affiliated entities became substantial holders of the mining firm as of Feb. 28, according to a Tuesday filing with the Australian and New Zealand bourses.

The capital management firm and its affiliates acquired 51.1 million shares in the company, representing 6.4% total voting power, the filing said.

Shares of the company fell nearly 1% in Australia and New Zealand in recent Tuesday trade.