The crater that keeps swallowing up houses

A huge abyss is gradually widening, and sucking in more holiday homes as the earth collapses. It looks as if a meteorite has struck from outer space, but in fact the crater lies above a collapsing potash mine.

In the Perm region of the Urals, the crater started caving in at the end of 2014 and when it was first reported its dimensions on the surface were a modest 20 x 30 metres.

By April this year, the Solikamsk hole's surface measurements were 58 by 87 metres. Now - five months later - it measures 122 by 125 metres and is still enlarging, as it threatens new dachas - holiday homes - and forest. The crater, visible from space,  is believed to be more than 75 metres deep. 

In April, an expert examining the hole said it was 'more or less stable', predicting it would 'remain so'. Yet it has still grown, with latest images taken from a helicopter over the hole show it far closer to the forest on both sides. 

The crater is close to the Solikamsk-2 mine owned by the world's number one potash producer, Uralkali. In November last year, there was underground flooding at the mine and the 1,300 employees were successfully evacuated. The sinkhole appeared around the same time.

The company, listed on the London and Moscow stock exchanges, linked the problems to an earlier mine flooding in 1995, which has been blamed on an earthquake. Uralkali is taking extensive action to limit the damage.

'Uralkali continues to eliminate the accident consequences and to minimize potential adverse effects,' said a company publication. 'The company continues pumping brines, working to strengthen the bridges between the mining fields Solikamsk-1 and Solikamsk-2, as well as plugging water carrying channels. 

'As of August 24, 2015 the dimensions of the of the hole at the level of the earth's surface is 122 to 125 metres. 

Uralkali also conducts hydraulic filling of old mines in order to reduce deformation of the rock mass. Mid inflow [of the brine] during the last ten days was 310 cubic meters per hour.' Owners of houses that disappeared into the hole have been told they will be compensated. 

The cause of the sinkhole is seen as different to the appearance of craters in northern regions of Siberia recently.

The Siberian craters - in permafrost regions - were the result of the melting of soil containing gas hydrates, leading to dramatic blowouts, say scientists.