Having just recorded an underground gin chamber in Arkengarthdale i have
been asking very similar questions. In this case the gin has long gone but
by recording the position of timbers sockets and a pile of "organic matter"
on the floor, (yes 200 year old horse manure), it has been possible to
locate the position of the vertical center post and the horse track around
it.
The horse track at about 6m diameter is almost haf the diameter of surface
sites which are on avarage about 11m dia. The gin was mounted off center
which allows extra space to one side which apears to be where the gin driver
sat on a shale ledge. The gin chamber is linked to the shaft via an eye hole
at roof level which suggest that the drum was probably above the horses
head, which as has already been suggested would create more space to turn
the animal around. It is probably better to think about the horse being a
pony. These can have quite a small turning circle (able to turn around in
the space of a stable) and if a wisbone yoke is used this would be easily
achieved without the need for complicated engineering.
The size of the rope drum is something which could affect the amount of
space below. If the rope is simply winding on and off the drum this would
need to be bigger (deeper) than one where a reciprocating system is used
with one end down the shaft when the other is at the top.
I don't think though that the Cornish can take the credit for designing gins
more likely that they came from Europe (see De Re Mettallica). They were
certainly widespread in coal mining areas, but then most people forget that
there were more "Cornish" engine houses in the coalfields than in Cornwall
and that many technologies applied to metal mining had already been tried
and tested on coal mines.
Martin Roe
Conservation Officer NAMHO
National Association of Mining History Organisations http://www.namho.org
Lead Mining in the Yorkshire Dales
http://www.mroe.freeserve.co.uk
The Industrial Heritage of Calderdale
http://www.halifaxcouriertoday.co.uk/ftpinc/calderheritage
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