On Monday some family members armed with sticks stormed the offices of the mine owners, smashing windows and accusing managers of not telling them what was happening.
"Why do people across the whole world know about the accident but we are standing out here knowing nothing about it?" asked Zhang Chuen-ling, brother of one of the trapped miners.
Many relatives said they have not even been issued with a list naming the miners thought to be trapped underground.
They have been buoyed by growing criticism in China's state-run media, with several reports accusing authorities of failing to protect workers and silencing reporting of the calamities that often strike mines and worksites.
"This seems to be a natural disaster, but when such natural disasters happen so often they cannot be just blamed on the pitilessness of nature," said the China Youth Daily.
According to a separate report in the China Daily, one man reported seeing mine managers on Friday trying to close the breach in the river rather than warning those underground.
|Tensions have begun to boil over as |
relatives wait for news [Reuters]
In an effort to calm rising tensions, authorities announced they would be offering accommodation to waiting relatives, as well as staff to "greet and console them", a notice on the central government's website said.
While hopes are fading for the trapped men, several miners managed to escape as the waters surged through the breached dyke and flooded into two separate mine shafts.
"When I heard the water it was like a howl," said miner Wang Kuitao. "It brought with it some kind of gas, it was cold air. Then the water started flooding the mine. I was at 700 metres below ground level then."
China's mining industry is the world's deadliest and has already claimed more than 2,000 lives in the first seven months of this year alone.
If, as many now suspect, the 181 men trapped by the floodwaters are confirmed to have died, it will be the worst mining disaster to hit China since 2005.
|Hundreds of rescue workers have been brought in to try to drain the mine shaft [Reuters]|