China's sinking coal-mining towns are largely the result of a failure to implement existing environmental legislation, a top geological expert has told RFA.
A three-decades-long coal-mining boom in the northern province of Shanxi has left hundreds of communities in imminent danger of sinking into the ground.
The Shanxi authorities say they now plan to relocate some 655,000 residents by the end of next year from former mining regions now deemed unsafe.
The industry has cost the government around 77 billion yuan (U.S. $11.6 million) in economic losses, local officials estimate.
Yang Yong, a subsidence expert based in the southwestern city of Chengdu, told RFA that Shanxi had paid a heavy environmental price for its massive contribution to the Chinese economy through coal production.
"There have been laws for quite some time in China saying that remedial operations must be undergone in mining areas, and limiting the amount of exploitation that can happen near river beds, major roads or infrastructure projects," Yang said.
He said the rules also require mining operators to ensure the safety of villages on the surface near the mines.
"Pits that are opened up underground are supposed to be filled in again afterwards," Yang said. "The same goes for open-cast mining."
Yang said local officials are to blame for failing to implement the regulations.
"Why don't they play a supervisory role?" he said. "Why are these rules not worth the paper they are written on?"
Yang said mine operators are charged a fee by local governments to cover the cost of filling in abandoned pits.
"The government should be using that money for that purpose," he said. "A lot of money has gone missing."
Skyrocketing energy demands
Intensive exploitation of coal seams in the past few decades to meet skyrocketing energy demands has undermined the geological structure of the earth in many locations across China, experts say.
On Aug. 15, 2011, the whole of Pangpangta village in northern Shanxi province was swallowed up by subsidence.
Photos of Pangpangta village posted on Chinese news websites and bulletin boards showed 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.
Earlier this month, a report based on satellite imagery showed alarming levels of subsidence in the Chinese capital, which is slowly sinking, with some parts falling by 11 centimeters (4.3 inches) annually owing to excessive pumping of groundwater.
The report in the journal Remote Sensing showed that Beijing has been suffering from land subsidence since 1935.
It linked the worst areas of subsidence with the concentration of aquifers and wells pumping out groundwater.
"It's clear that water extraction is a factor here," Yang told RFA. "There are also mines all around the outskirts of Beijing, for example at Mentougou in the municipal, and at Kailuan just to the north, which have been mined for many years now."
"These operations, and even mining in Hebei and Shandong, have in turn affected the groundwater," he said. "These mines may be some distance away, but they will draw off ground-water in Beijing if they are in the same aquifer."
The issue of subsidence has also sparked social unrest across the country in the worst-hit areas.
In June 2014, more than 3,000 villagers from Henan's Xuchang county faced off with riot police amid protests over local mining operations which they said had devastated the ground near their homes, swallowed up a road, and left cracks in their houses.
Reported by Gao Shan for RFA's Mandarin Service. Translated and written in English by Luisetta Mudie.