MANDALAY, Myanmar — At least 54 jade miners in northern Myanmar were believed to be dead on Tuesday after a huge mound of tailings collapsed into an open-pit mine, burying workers and heavy equipment, officials said.

The disaster occurred late Monday night in the remote Hpakant area of Kachin State, where miners produce billions of dollars’ worth of jade each year under harsh working conditions.

Rescuers began searching for survivors after dawn on Tuesday, but officials said there was little chance that anyone would be found alive at the mine, which is about 100 feet deep and covers about five acres.

Three bodies were recovered by late afternoon, said Tin Soe, a member of Parliament who represents the area.