Taking Hazel's comment regarding the information given at last week's lecture by Professor Paul Younger, on Christmas Eve 2003 I received an email from Environment Agency containing the following information about the minewater levels at Horden shaft:
"The water level in Horden shaft was -21.39 m AOD on 5 June 2003. The level on 5 June 2002 was -35.69 m AOD, a rise of 14.3 metres in one year. The base of the Permian aquifer at Horden is -96.93 m AOD."
This was a great shock to me and I therefore asked EA for confirmation of the figures. I received this confirmation on 8th January 2004.
To complete the picture the top of the magnesian limestone is at a depth of about 34.13 metres above Ordnance Datum (AOD), the bottom of the limestone is at a depth of -80.16 metres AOD and the bottom of the Yellow sands, i.e. the base of the aquifer, is at -96.93 metres AOD.
From the above information it can be clearly seen that the minewater has been polluting the aquifer for some time.
Alan.
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