Complex sentence: A design flaw was being rectified at the time of the flooding, which newspapers reported as being the result the recent closure of two nearby collieries that had shut down due to flooding and the absence of their pumping mechanisms had increased the volume of water present.
Split into simpler sentences: A design flaw was being rectified at the time of the flooding, which newspapers reported as being the result the recent closure of two nearby collieries. Those collieries had themselves shut down due to flooding and the absence of their pumping mechanisms had increased the volume of water present.