AFP Zaw Moe Htet, AFP AFP Handout, Myanmar Fire Services Department, AFP AFP Zaw Moe Htet, AFP
Rescuers worked all morning to retrieve the bodies from a mud lake, pulling them to the surface and using tyres as makeshift rafts.
Police told AFP that 99 bodies were found by 12:00, with another 20 injured.
They said search and rescue efforts had been suspended because of more heavy rains.
The workers were scavenging for the gemstones on the sharp mountainous terrain in Hpakant township, where furrows from earlier digs had already loosened the earth.
Photos posted on the fire service Facebook page showed a search and rescue team wading through a valley flooded by the mudslide.
Rescuers carried bodies wrapped in tarpaulins out of the mud lake as a deluge poured down from above.
Unverified footage of the scene showed a torrent of sludge crashing through the terrain as workers scrambled up the sharp escarpments.
Police said the death toll could have been even higher if authorities had not warned people to stay away from the mining pits the day before.
"It could have been hundreds of people dead - more than this, but the notice might have saved some," said superintendent Than Win Aung.
Open jade mines have pockmarked Hpakant's remote terrain and given it the appearance of a vast moonscape.
Demand from China
Landslides in the area are common, especially when rainfall hammers the muddy terrain during Myanmar's notoriously severe monsoon season.
The workers combing through the earth are often from impoverished ethnic communities who are looking for scraps left behind by big firms.
A major collapse in November 2015 left more than 100 dead.
A mudslide buried more than 50 workers last year, when a long recovery effort saw police digging through a "mud lake" to retrieve bodies from the sludge.
Myanmar is one of the world's main sources of jadeite and the industry is largely driven by insatiable demand for the green gem from neighbouring China.
The mines are mired in secrecy, though Global Witness claims their operators are linked to former junta figures, the military elite and their cronies.
The watchdog estimated that the industry was worth some $31 billion in 2014, although very little reaches state coffers.
Northern Myanmar's abundant natural resources - including jade, timber, gold and amber - help finance both sides of a decades-long civil war between ethnic Kachin insurgents and the military.
The fight to control the mines and the revenues they bring frequently traps local civilians in the middle.