The message
from John Rouse contains these words:
In article , TheScullster
writes

I don't expect that ground water generally will be a problem.
Our house is almost at the top of a hill, so drainage of the garden
generally should be OK.

Oh we're at the top of a hill, its just that the coal seams run at an
angle of about thirty degrees to the horizontal, and as our garden
slopes at about thirty degrees the other way, we have two, if not three,
coal seems bassetting in our plot.

I guess the good news is that we have somewhere for the water to drain
to.

And two, if not three drift mines?

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Rusty Hinge
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