UPDATE 3-Kazakh coal mine blast kills at least seven

(Recasts with company statement, details, byline)

By Sergei Tereshchenko

ABAI, Kazakhstan, Jan 11 (Reuters) - An explosion killed at least seven coal miners on Friday and left another 23 missing in a Kazakh mine owned by the world's largest steel maker, Arcelor Mittal (MT.N) (ISPA.AS).

Rescue workers battled an underground fire at the Abaiskaya mine in central Kazakhstan as they searched for the missing miners, government and emergency officials at the site said.

At least 12 other workers were injured in the explosion, which struck at around 9:30 a.m. (0330 GMT) when 190 miners were working below ground.

Lakshmi Mittal, the billionaire founder and chief executive of Arcelor Mittal, said an investigation had been launched.

"We are doing everything we can to locate those still missing and to assist the bereaved," he said in a statement.

An explosion at another mine owned by Arcelor Mittal in the same region, the Lenin mine, killed 43 workers in 2006. Two earlier blasts, in 2002 and 2004, killed more than 30 miners.

Coal mining accidents occur frequently in the former Soviet Union, where safety practices are often less strictly observed than in Western mines. Explosions in coal mines are most often the result of a build-up of methane gas, although emergency officials did not confirm the cause of Friday's blast.