RE:Quick ? for RetiredGeo There a regulations re abandoning drill holes. The older holes might not be used whereas the more recent ones might have been capped and could be used. Abandoned drill hole have to be restored so as not to contaminate the ground water.
True story, I was there, when blasting underground in a gold mine in Chibougamau Quebec, they occasionally ran into a water problem. Some of the assay holes had been drilled in winter and when completed they were not properly plugged. Thus when encountered this was a column of water with a 700 foot of head. Serious pressure and not easy to access and stop the flooding. As they say, shot happens.