Hi paul,
The consulting geologist for the later reworking was K C Dunham and there is a folder with alot of his reports in the Durham Record office (Ref No. D/Dun 16/15
Strontian lead - zinc - barytes, Argyll, 1947, 1964, 1985, Laudale, 1980)
I have a copy of a video showing a guy drilling in the opencut and various bits of the plant working, PM me if you are interested in seeing it.
Cheers
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