Rio Tinto has increased its cash offer for Riversdale Mining, valuing the coal miner and its African operations at $4bn.

Rio Tinto has increased the offer price from $16.00 to $16.50 a share, if it obtains an interest in over 50% of Riversdale shares by 23 March 2011.

India’s Aditya Birla was shortlisted among the bidders for Australian miner Whitehaven Coal, which has been valued at $3.5bn, and is planning to launch a binding offer soon.

Inner Mongolia Baotou Steel Union is planning to purchase a 100% stake in Baotou Iron and Steel group Barun Mining and the exploration rights to an iron ore mine in Bayan Obo, Inner Mongolia, from its parent Baotou Iron and Steel group.

Baotou Steel will raise up to CYN6bn ($911m) through private placement to pay for the acquisition.

Tata Power is looking to acquire a 30% stake in a coal unit owned by Indonesian conglomerate Sinar Mas and has emerged as one of the shortlisted bidders.

Sinar Mas is seeking at least $300m for a 30% stake.

Forge Resources has made a deal with rare-earths miner Lynas to purchase and develop the Crown polymetallic deposit at the Mount Weld project in Western Australia.

Forge will pay Lynas A$20.7m (US$20.3m) in cash, and a further A$7m (US$6.8m) options to acquire Forge shares over five years.

Goldgroup Mining has acquired DynaResource de Mexico for $18m, and, as per the transaction, Goldgroup will own 50% of the San José de Gracia gold project in Sinaloa, Mexico.

Eldore Mining Corporation has acquired a 100% interest in the Baita Copper mine in West Romania, for €15m ($20m) and reimbursement of €0.2m ($0.27m).

Korea Resources (Kores) has signed a deal with Peru’s Ferrobamba to develop mines with iron ore reserves of 400 million tons in Peru.

KORES and Ferrobamba will invest $5m to explore 13 mines for the next two years and KORES will secure a 40% stake in the mines.