Two points re leats on open moorland, to openworks and other mine sites:
firstly in many cases it is easy to miss minor leats which have become what
David Bick called "sheeptrack leats". On Bodmin Moor following and mapping what
appears to be just a sheep path (particularly in areas normally covered in
bracken) often reveal that their course suggests they were originally leats.
Secondly, in areas where below-adit working occurred many so-called "leats"
were probably in fact drains to keep surface water away from lode outcrops as
much as possible. Of course the water so collected could have been made use of
for dressing etc. at a lower level. Good examples include Eylesbarrow on
Dartmoor, and Stowes, South Phoenix, West Rosedown and Wheal Jenkin on Bodmin
Moor. Some of the latter are very faint & seem to have been missed from previous
archaeological surveys.
One possibility that struck me some years ago when looking at leats at Bagtor
feeding openworks was that perhaps where normal surface water was in short
supply, the main source of water may have been snow melt. Not sure what climatic
conditions would have been at the time these were worked, but perhaps it might
have been less labour intensive to carry snow into the catchment of a leat than
to attempt to work a lode outcrop without the aid of water. Maybe an over
fanciful idea but who knows?
________________________________
From: Robert Waterhouse <[log in to unmask]>
To: [log in to unmask]
Sent: Thu, 28 April, 2011 11:24:05
Subject: Re: Leats to openworks
Dear Graham,
I'm not sure about chronology - some of our sites have evidence of multiple
workings, as they have different types of extraction pits/trenches, and
several are known to have been worked as early as the mid-C16 (documentary
refs).
I personally suspect they started low down on the steep valley sides where
lodes commonly outcropped at surface, then followed them uphill. The points
the leats arrive at the openworks tend to be relatively high, though that
may have more to do with the most practical points to take the leats from
their source streams.
One of them (the Rubbytown Leat) can be seen in the foreground of the JMW
Turner painting 'Crossing the Brook' in the National Gallery, London.
We have documentary evidence for its existence by the mid-C18 and I suspect
its rather earlier.
Robert
-----Original Message-----
From: mining-history [mailto:[log in to unmask]] On Behalf Of
[log in to unmask]
Sent: 28 April 2011 10:09
To: [log in to unmask]
Subject: Re: Leats to openworks
Looking at alot of open workings on the north Penines especially the
cross fell area there is the classical hushes like Dun Fell but even
the learts leading into these can be very small and also the associated
reservoirs. Other open works do appear to have leats direct from small
streams into them without reservoirs and in other places some of them
do appear to go through small dressing floors before going into the
open work.
The main problem with interpretation is trying to work out a
chronology. did they start working at the bottom upwards top down of
allong the full lenght or in sections?
Graham Brooks
>----Original Message----
>From: [log in to unmask]
>Date: 28/04/2011 9:51
>To: <[log in to unmask]>
>Subj: [mining-history] Leats to openworks
>
>Robert,
>
>Is there any evidence of reservoirs for the water or does it go
directly
>into the openwork? From what you say, there would have been
>insufficient water for significant pumping. While I understand that
>your openworks are not quite the same, our hushes often had lots of
>minor leats running into them.
>
>Regards,
>
>Mike Gill
>
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