Minewater first appeared in Saltburn Gill on 18 May 1999, since then the beck has been stained with ochre, this occured 35 years after Longacres mine actually closed so many think its probably due to the construction of the Skelton – Brotton bypass between Longacres and this location causing some movement underground.
This problem also exposed a legal loophole whereby neither the current landowners nor former operators can be held responsible. The coal authority is also not currently responsible for old metal mines.
An extrememly informative article on the subject can be found in a recent issue of Geoscientist.
The interesting overlay of the workings is to be found on the informations boards by the beach.
This is an interesting phenomena. I have seen other such cases where mine water starts to appear many years after closure. I don’t know really what the solution would be, other than to attempt to re-enter the mine in question and try to close off the source of the pollution.
PS just read the article. Very interesting – thanks Chris for adding the link!
Original research on the cause of the problem did not attribute it to the By-Pass construction. There was no evidence that that was the cause. I can assure readers that no mine workings or subsidence was encountered during construction.
The most probable cause of the pollution is the failure of the plug in the mine drainage adit. The worked seam(s) in the Cleveland Ironstone are quite close together and would have been drained via the lowest point in the mine to the lowest point in the local topography; an outfall by the beck where the contaminated water now emerges. If this was above the worked seams it would have been pumped prior to closure; if below, then it would simply have been a small tunnel working on gravity.
The failure of the plug could be to a number of causes, not least the fact that the plug might not have been designed to stop water emerging, but merely loose backfill to the hole to prevent entry. A rise in the water level in the abandoned workings of only a few feet – a leak through either of the shaft linings at Long Acres would do the trick, for example – would be enough to start the polluted water flow.
Stabilisation by grouting – the Scots are spending/have spent a mint on this after the debacle of the railway in East Lothian, which collapsed into old workings a few years ago – is one way of dealing with old room and pillar mines at shallow depth to protect new infrastructure at ground level. Any works to ancient structures, such as old mines, implies risk of pollution; quantification of that risk is significant business these days.
Something to look forward to in the hydraulicly fracked future……