Northeast China's Heilongjiang Province will close down 200 small-sized coal mines with serious hidden dangers against production safety, said Vice Governor Liu Haisheng Saturday.

The official said the government's decision was made after a production safety overhaul toward all the coal mines in Heilongjiang.

The overhaul was performed after a disastrous blast took place on Nov. 27 in the Dongfeng Coal Mine run by the Longmei Group, which killed 169 miners, with two others still missing.

Liu said the overhaul targeted at such problems as the overtime running of mines, poor ventilation systems, bad coal-dust-proof equipment and over gas density underground.

The official said many small coal mines in Heilongjiang, including some run by the state, have more than one above-mentioned problems and are forced to stop production to remove the hidden dangers.

By the end of this year, 200 mines that still don't meet the national standards of production safety will be shut down and all their power, water and explosive supplies will be cut off, Liu said.