I mainly recall seeing them when I was working on a contract doing repairs to a railway viaduct which I believe was called Harpers Brook, round about 1981.
Foraky still had at that time, a sprayed-concrete operation who did work for the railway and occasionally odd jobs would appear from various sources and be done by personnel from the drilling and freezing sides, usually under 'mining' project numbers. The Doe Lea Colliery ventilation shaft was another such job.
the main thing I remember about the site was the 'Fort Apache' atmosphere; a totally uncontrollable level of theft and vandalism due to its proximity to Corby, with its abundance of unemployed steel workers who had come down from the Clyde some years before on the promise of council houses and work, and found themselves unemployed and effectively unable to move even if there WAS any work, which there wasn't; and being 'union' men, for sure they were steelmen and weren't going to do anything ELSE.
we eventually resorted to placing the whole site stores in two roll-along containers which were towed to a nearby farm every evening. You couldn't leave as much as a spanner on the scaffolding overnight, and after the ladders were stolen we changed the scaffolding so you could walk onto it from the railway bank 😢
I wouldn't care to try that today..... the viaduct itself is still there, but whether the line still runs, I have no idea. Its function at the time was to serve the remaining ironstone extraction, and the bridge had to be kept in service, at minimum cost, for a few years to see this out
''the stopes soared beyond the range of our caplamps' - David Bick...... How times change .... oh, I don't know, I've still got a lamp like that.