Police said the landslide in Kachin state was so great it created a "mud lake" that engulfed the workers' living quarters along with some 40 vehicles.
Landslides caused by jade mining, an industry with few regulations, kill dozens in Myanmar every year.
A local official said it was "very difficult to retrieve the bodies" and only three had been recovered.
"They won't survive," Tin Soe, a local lawmaker, said. "It's not possible because they are buried under mud."
The ministry of information identified the companies involved in the accident as Shwe Nagar Koe Kaung and Myanmar Thura Gems.
Neither has yet commented, although the director of Myanmar Thura Gems, Hla Soe Oo, told AFP news agency he was on his way to the site.
The search and rescue efforts are ongoing, officials said.