The company will buy ICG by acquiring all of the outstanding shares of ICG common stock for $14.60 per share in cash without interest.
Earlier this month, the companies signed a definitive merger agreement pursuant to which Arch agreed to commence the tender offer.
Arch Coal is a US-based coal producer, with more than 160 million tons of coal sold in 2010.
The company’s national network of mines supplies cleaner-burning, low-sulfur coal to customers, including international power producers and steel manufacturers.