It was meant to be a remediation program to repair extensive mine subsidence damage to Sugarloaf State Conservation Area in the Lower Hunter.

Instead it turned one environmental disaster into another.

Contractors working for coal giant Glencore Xstrata pumped more than 180 tonnes of concrete into a tributary of Cockle Creek at Lake Macquarie.

The concrete creek, uncovered as part of Fairfax Media's investigation into mine subsidence at the state conservation area, stretches more than 400 metres down a hillside and dries up less than a kilometre from Cockle Creek that leads to Lake Macquarie.