Deep in the coal heartlands of northern Shanxi province, people in Helin village are fighting a losing battle as the ground beneath them crumbles: patching up cracks, rebuilding walls and filling in sinkholes caused by decades of coal mining.

 

Around 100 pits in Helin - buried in the hilly rural outskirts of the city of Xiaoyi - have been exhausted, and cluttered hamlets totter precariously on the brittle slopes of mines.

 

But while local authorities have begun evacuating hundreds of thousands of residents most at risk elsewhere in Shanxi province, Helin's situation – though serious - isn't yet considered a priority.

 

Mines that burrowed under villages and towns during China's three-decade coal boom have left the authorities with the need to evacuate hundreds of communities in danger of sinking.

 

Shanxi province alone plans to move 655,000 residents by the end of next year from unsafe old mining regions, with the cost of relocation estimated at 15.8 billion yuan ($2.37 billion). The Shanxi government estimates coal mining has cost the province 77 billion yuan in "environmental economic losses".

 

Mine-induced subsidence is not unique to China, but its problems dwarf those of other countries.

 

According to official data, coal mining had already caused as many 26,000 geological disasters by the end of 2014, and as much as 10,000 square kilometers of land has been affected, an area the size of Gambia in Africa, according to some estimates.

 

China's land ministry said last month it would spend 75 billion yuan ($11.27 billion) over the next five years to restore mined land and treat mining waste nationwide.