No guesses at the location of the quarry so here's a few clues:-
1) The English translation of the nearby area has a bleak-sounding ring to it, as does the sound you can regularly hear from an essential building half a mile away.
2) It is a few hundred metres from a park where some expensive-sounding animals were kept in days gone by.
3) It is within 10 miles of the three towns area.
4) Hugo, Jack, Dave.R. and maybe Mr.& Mrs Hollins must have walked past it, but maybe didn't see it.
5) The business in the buildings has changed hands recently and is doing very well now with new contracts to provide locally sourced produce.