Numerous lakes of different depths have appeared as a consequence of coal mining in the Šaleška valley. The water level in the Velenje lake is almost eight metres higher than the Šoštanj lake. There are cracks in the dyke built between the lakes. If the dyke was breached, half of Šoštanj would be flooded, warns Peter Radoja, commander of the local civil protection unit. 'The violent wave would certainly pour through the Šoštanj dyke and thus flood a great part of Šoštanj, all the way to the Penk gorge. Water would flood 50-100 houses.'

Not enough material to upgrade the dyke
The dyke is constantly sinking due to coal mining, but it is at the same being raised with a mixture of ash and gypsum form the Šoštanj Thermal Power Plant. The Velenje Coal Mine acknowledges that they currently lack the material for the strengthening of the dyke, but there is no danger. 'There is as much material as there is coal that the thermal plant buys from us. Sinking is currently greater than the quantity of the material which we are getting right now, but everything balances out in the long term."
Could an earthquake destroy the dyke?
The Velenje Coal Mine claims that the dyke would not burst even during an earthquake. Drago Potočnik, head of the technical department, explains that the dyke is more than 400m wide at its narrowest part. According to their statics experts, it would still be safe even if it was only 150m wide. "I think that we have taken good care of safety. Even when coal mining ends, the dyke will still be wider than 150m."
Mateja Kumer, an architect and Šoštanj Municipality councillor, fears that this dyke will not even be able to withstand the pressure of the next minor tremor, because the quality of the material built into has declined. The dyke is cracking and water leaks into it. Small lakes have appeared on it. "The land is constantly shaking due to coal mining. I think that one big tremor would be enough to cause a catastrophe. I live in an area where mining takes place directly underneath the houses and I feel tremors every day" says Kumer.
Cracks in the dyke are the final straw
Šoštanj locals also constantly complain about bad smells. Gases from coal mining are coming to the surface via an air-shaft. ''In 1931, the Slovenec newspaper reported that Šoštanj was a metropolis in this part of Slovenia. We were a socially and culturally developed town, we had thermal baths and we lived in a completely different spirit than today. These industries have exhausted us, many people have moved out, for it is not possible to live creatively here. Šoštanj has become a dormitory town," says Mateja Kumer.
The Velenje Coal Mine understands the problems of the Šoštanj locals, stressing that their fears of the lake flooding are groundless. They promise to close the cracks in the dyke and drain the small lakes on it.