David Sables wonders "if anyone had any information on shot blasting using lime ..".
I don't, but I may be able to point to some possible sources, because this method of ground
breaking was used by Sergeant-Major Ince and men from the Company of Soldier Articifers
(a forerunner of the Royal Engineers) to drive tunnels in Gibraltar during the Great Siege
of 1779-1783. Ince's idea was to drive a tunnel several hundred feet up within the North Face
of the rock and establish gun positions which overlooked the Spanish Lines, being able to
shoot along the lines of their trenches on the Isthmus below. His plan was approved but,
because of the siege, gunpowder was strictly rationed and not to be used in tunnelling,
so they used quick-lime "blasting". This caused little disturbance to the surrounding rock,
and in consequence the tunnels he made, including the gun positions St George's Hall and
Cornwallis Hall, are said by Rosenbaum (Ref 1) to be "amongst the most stable" of the 30
miles of tunnel on the Rock.
Rosenbaum also says "the early tunnelling period is well documented in detailed accounts"
and I list these below.
References
1. "The Tunnels of Gibraltar", M S Rosebaum & E P F Rose, published 1991 by the
Gibraltar Museum, 18-20 Bomb House Lane, Gibraltar. 32pp, A5 size (no information on
quicklime "blasting" other than the remarks quoted above)
2. "The Galleries, Gibraltar" by E G M Goodwin, Beauland,Matis & Co, Gibraltar 17pp
3. The Gibraltar Tunnels, in "Proceedings of the Archaeological Society of Gibraltar",
1956-57, pp 37-44.
4. "Gibraltar, Our Heritage", G. Palao, Ferma, P.O. Box331, Gibraltar. 121pp
(I have to confess I have not read Refs 2, 3 & 4, so only have Rosenbaum's word for their
usefulness in this context).
Likewise, I do not know if the Royal Engineers Museum in Chatham has any information
on Ince's tunnelling activities, but they may have. www.remuseum.org.uk
Tony Brewis
(Tunnelling Troop, Fortress Engineer Regiment, Royal Engineers, Gibraltar, 1953-54)
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