Eight miners were conducting a safety check of the mine in Xiahoe Township when the blast occurred at 11 a.m., the state-run Xinhua News Agency reported.
Five of the miners were rescued and one died on the way to the hospital.
The four injured miners were in stable condition at the hospital, the county's information office said.
The other three remained trapped, the news agency said.
Authorities were investigating the cause of the explosion.