Scores die each year working in the country's lucrative but poorly regulated jade trade, which uses low-paid migrant workers to scrape out a gem highly coveted in neighbouring China.
The disaster struck at a mine in Hpakant township close to the Chinese border in Kachin state, where billions of dollars of the precious mineral is believed to be scoured from bare hillsides each year.
“About 70-100 people are missing” following the landslide that struck around 4:00am, said rescue team member Ko Nyi.
“We've sent 25 injured people to hospital while we've found one dead.”
Hundreds of diggers had returned to Hpakant during the rainy season to prospect in the treacherous open-cast mines, according to a local activist, despite a junta ban on digging until March 2022.
“They mine at night and in the morning they tip out the earth and rock,” said the activist, adding the added weight had caused the land to slip down into the lake.
Ko Nyi of the rescue team also said increased pressure from the weight of dumped soil and rock had pushed the ground downhill into the lake.
Around 200 rescuers were working to recover bodies, with some using boats to search for the dead in a nearby lake, he added.
Access to the mines in the remote north of the country is heavily restricted by the military and internet access is patchy.
Local outlet Kachin News Group said 20 miners had been killed in the landslide.
Myanmar's fire services said personnel from Hpakant and the nearby town of Lone Khin were involved in the rescue effort but gave no figures of dead or missing.
Jade and other abundant natural resources in northern Myanmar, including timber, gold and amber, have helped to finance both sides of a decades-long civil war between ethnic Kachin insurgents and the military.
Civilians are frequently trapped in the middle of the fight for control of the mines and their lucrative revenues, with a rampant drug and arms trade adding to the conflict.
Last year heavy rainfall triggered a huge landslide in Hpakant that entombed nearly 300 miners.
Watchdog Global Witness estimated that the industry was worth some $31 billion in 2014.
But corruption means very little reaches state coffers.
A military coup in February also effectively extinguished any chance of reforms to the dangerous and unregulated industry initiated by ousted leader Aung San Suu Kyi's government, watchdog Global Witness said in a report this year.
The coup has also sparked fighting in Kachin state between local insurgents and the Myanmar military, Global Witness added.
In May, the military launched air strikes against the insurgents, who later told AFP they had shot down a helicopter gunship during fierce clashes in the country's far north.