Part of a hillside at the mine at Pangwa in Kachin state on the border with China slipped away early Tuesday, a source at the mine told AFP, requesting anonymity.
"The whole hill fell down... it wiped out even big trees," the source said, adding that at least seven people were unaccounted for.
Rescuers have found five bodies, including two Chinese citizens, two security guards and one worker, the source said.
AFP has contacted the Chinese embassy in Yangon for comment.
Local media reported that five people had been killed and at least 20 people were still missing from the mine.
Jade and other abundant natural resources in Myanmar's far north -- including timber, gold and amber -- have helped finance both sides of a decades-long civil war between ethnic Kachin insurgents and the Myanmar military.
The region is also home to heavy rare earth elements which are vital for magnets in electronic vehicles.
There are over 300 mining sites around the town of Pangwa, the watchdog Global Witness said last month, citing satellite imagery.
The rare earth industry in Myanmar was worth around $1.4 billion in 2023, according to the watchdog.
During the June to October rainy season, landslides are a regular and deadly hazard for the thousands of migrant workers who travel to Kachin state to scrape precious metals and minerals from its hills.
In 2020, heavy rainfall triggered a massive landslide at a jade mine in Hpakant township that entombed nearly 300 miners.