More than 300 rescuers have joined the search for 22 workers who were trapped underground after an explosion ripped through a gold mine under construction in east China's Shandong Province, local authorities said.

The accident took place at 2 p.m. Sunday at the gold mine in Qixia City, said a spokesperson with the government of Yantai City, which administers Qixia. The local government did not receive an accident report from the mining company until Monday evening.

Due to damage the communication system sustained in the blast, rescuers have so far been unable to contact the trapped workers, said the spokesperson.

By 10 a.m. Tuesday, large machinery such as drilling machines has been installed at the site. A drill pipe has reached a depth of more than 360 meters, and rescuers are being lowered to clear obstacles and rescue the trapped miners, said Sun Shufu, an official with the emergency management department in Yantai.

The gold mine is owned by Shandong Wucailong Investment Co. Ltd., a local company in Qixia.