SHIJIAZHUANG, June 2 (Xinhuanet) -- After some 20 hours of emergency rescue efforts, three miners who were buried in a gold mine collapse were rescued Wednesday night in northern China's Hebei Province, local police said.

    Rescuers said all the trapped miners walked out from the collapsed mine in Lingshou County by themselves and were now in good health conditions.

    The accident took place at 6 p.m. Tuesday while the three miners made a clearance and check in a wasted mine, which had been purchased by a Shihu Gold Mine, both located in Lingshou County.

    Preliminary investigation showed the collapse of the wood shelf,which held up the ore in the mine, led to the accident.

    Though previous reports said rescuers encountered difficulty inremoving the collapsed ore, they succeeded in opening the blocked mine shaft Wednesday afternoon and pump oxygen into the mine, according to local police and government sources.