Robert,
The balance bob would have had a box attached at the inward end of the beam
loaded with scrap iron, rocks, etc., which gave the balancing weight. A beam
on its own, being probably symmetrical, would not have contributed anything.
A 6ft by 6ft box on plan would be quite normal.
Iain Wright
-----Original Message-----
From: mining-history [mailto:[log in to unmask]] On Behalf Of
Robert Waterhouse
Sent: 19 August 2008 14:16
To: [log in to unmask]
Subject: Balance bob pits at shaft throats
Dear List,
I've recently seen two mid-C19 mortared stone angle/balance bob chambers in
East Cornwall and West Devon, which are immediately alongside shafts, whose
sides curve inwards immediately adjoining the shaft. This narrows the
chamber considerably to a width of about 2-3ft, from a total chamber width
of about 8ft.
Does anyone know why this was done? Someone suggested that it might make
such a pit more stable where it adjoins the shaft, but as I haven't seen
these anywhere else, I'm not sure.
Robert Waterhouse
Morwellham Quay Archaeologist
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