01-01-2004, 10:15 PM
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Builders' sand for drainage?
The message
from (Nick Maclaren) contains these words:
I don't think sand at that depth would remain in free granular form, but
would be sandstone by now.
Not necessarily. To create sandstone, the pressure and temperature
has to be high enough to liquify something to glue the grains
together.
Pressure maybe, but a lot of sandstone is 'cemented' with precipitated lime.
That salt in Cheshire has been there for a very long time, isn't very
close to the surface, and is, IIRC, sandwiched between two impervious
layers of rock.
Yes.
So much sand lies at the surface that no-one is going to mine the stuff,
anyway.
I was thinking of the (fairly common) circumstance where something
else (like salt) is mined, and the sand is a waste product.
I can't think of anywhere where salt is mined mixed with sand - though
I'm not saying it doesn't happen. The salt in Cheshire is more-or-less
rock, and riddled with tunnels and galleries. I've always meant to visit
the salt museum when I've been in Northwich: I shall one day - my
brother and his family live near there. (And there's lots of surface
sand there too - his village is Sandiway.)
--
Rusty
Open the creaking gate to make a horrid.squeak, then lower the foobar.
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