The mining industry has been just as active this week as it was the last with companies big and small investing in opportunities around the world.

Rio Tinto concluded its second tranche of investment in Ivanhoe Mines, raising its shareholding by 9.8% to 19.7%.

The second tranche comprises 46,304,473 common shares at an $8.38 per share subscription price for $388,031, 483.74 total consideration.

Mining and exploration company Elkhorn Goldfields signed a letter of intent with gold miner Apollo Gold to acquire all outstanding capital stock in Montana Tunnels Mining, Apollo’s indirect wholly owned subsidiary for $9m.

The agreement also covers Montana Tunnels‘ 50% stake in the joint venture pact with Elkhorn’s affiliate Elkhorn Tunnels, the Diamond Hill mine and mill and all ancillary assets.

Both companies agreed to proceed with the drafting of definitive transaction documents to complete the transaction.

At the smaller end of the scale, junior miner Jiminex says it will buy a 100% stake in the Misehkow gold property located in north-western Ontario, Canada, for $54,000 and 100,000 common shares.

The property contains 21 contiguous non-patented mining claims amounting to 299 claim units with a 48km2 area.

LS-Nikko Copper also signed an option agreement with Inmet Mining to purchase a 20% option interest in the Cobre Panama copper project in Panama.

In the east, China’s state-owned sovereign wealth fund China Investment Corporation (CIC) will invest $15m in Ivanhoe Mines subsidiary Canadian coal company SouthGobi Energy Resources for a 15% share in the latter’s Mongolian coal projects.

CIC’s investment will help SouthGobi expand production at the Mongolia-based Ovoot Tolgoi open-pit mine to eight million tonnes of high-quality coal per annum from the present sales target of 1.5 million tonnes for 2009.

Britain’s Barclays Bank increased its stake in Chinese gold producer Zijin Mining from 8.84% to 9.19%. The bank purchased 14.22 million shares of Zijin Mining at a HK$8.12 average share price.

And Australian miner BHP Billiton started accepting bids for its $500m Maruwai coal project in Indonesia, which is expected to yield one million tonnes of metallurgical coal per annum.

BHP is receiving bids for 100% of the project and also for 25% minority shares. Indonesia’s PT Bumi Resources is one of the bidders for the project. The miner has not revealed how much of the project it proposes to sell.

Australian gold explorer Perseus Mining has decided to raise $58.5m in capital to help develop its Ghana-based Ayanfuri Gold Project.

Perseus is currently pursuing an exploration programme to expand its seven million ounce gold resource base, with seven drill rigs in operation at Ayanfuri and Tengrela in the Ivory Coast.