UPDATE 1-Kinross Gold ups stake in Millrock Resources

* Kinross to own about 6.4 percent of Millrock shares

* Kinross invests C$250,000 in Millrock

* Millrock shares touch year-high, pare early gains

April 6 (Reuters) - Millrock Resources Inc (MRO.V) said Kinross Gold Corp (K.TO) raised its stake in the company to 6.4 percent by investing C$250,000 in a private placement, sending Millrock shares up to a new year-high.

Kinross purchased about 0.8 million shares in the small mining and exploration company at 29.725 Canadian cents each, Millrock said in a statement.

The financing is related to a joint venture option agreement concerning the Council gold property in western Alaska, for which Kinross had 60 days to buy the shares but chose to make the share purchase immediately, it said.

From a prior financing arrangement, Kinross also holds about 1.1 million warrants to buy shares at 21 Canadian cents that may be exercised prior to June 4, 2011, Millrock said.

Shares of Vancouver-based Millrock rose 8 percent in morning trade but pared the gains and were flat at 36 Canadian cents in midday trade on the Toronto Venture Exchange. (Reporting by Gowri Jayakumar in Bangalore; Editing by Gopakumar Warrier)