Local residents in a mining district of northern China's Hebei province say a huge expansion of coal mining under their homes has made them unsafe.
Fears that those homes could collapse flared into violent clashes last week between hundreds of villagers and police in Hebei's Jianming township, according to residents, who accuse local mining bosses of carrying out breakneck expansion of coal-mines with scant regard for safety.
"This has been going on for four years now," said one Jianming resident surnamed Liu. "I can't get to sleep at night."
Liu said the mining company has strong ties to local government officials, making it hard to complain about its activities, which local people say are illegal.
"They have got good relationships with officials at township, county, and municipal levels," Liu said. "No one has come to investigate the matter of illegal mining."
"The voices of ordinary people are being suppressed, and the government just listens to the mine bosses," he said.
Photos supplied to RFA's Cantonese service by the villagers showed large holes in the earth next to the stone paving of a footpath.
Calls to the cell phone of Cai Hongkui, the mayor of nearby Zunhua city, which administers the area, went unanswered on Wednesday.
An official who answered the phone at the Jianming township government offices declined to comment. "I don't know about this," the official said.
Calls to the Da'anlezhuang village Party committee offices also went unanswered during office hours on Wednesday.
Villagers said the problems with ground subsidence had worsened since the local coal mine changed hands in 2007.
Since then, the mine has continued to expand in all directions, in spite of the fact that police have cordoned off large areas of their village as "subsidence areas," Liu said.
He said police had surrounded dozens of villagers who gathered outside the gates of municipal government offices last week to complain about the subsidence, beating some of them.
"We were outside the municipal government, and then a lot of police and armed police arrived," Liu said. "They surrounded us and some of them beat us up."
"They even beat us with butts of their guns, four people against one," he said. "A lot of us got hurt, although no one's life was in danger."
According to investigative journalist Gao Qinrong, intensive exploitation of coal seams in the past few decades to meet skyrocketing energy demands has undermined the geological structure of the earth itself in many mining counties in northern China.
"Underground, it is hollow," he said in a recent interview.
On Aug. 15, the whole of Pangpangta village was swallowed up by subsidence.
Photos of Pangpangta village posted on Chinese news websites and bulletin boards show houses fallen into chasms in the earth, huge cracks along a village street, and collapsed and damaged buildings similar to a scene after an earthquake.
Rather than focusing on Pangpangta as an isolated incident, however, Gao has investigated the problem of mine collapse and land subsidence across the whole region.
He has recently received anonymous threats warning him to "take care" of his personal safety.
Reported by Fung Yat-yiu for RFA's Cantonese service. Translated and written in English by Luisetta Mudie.