> perhaps they re-used the hole and just drilled it deeper So many things could be going on underground (types and shapes of materials) that would make your lo

> perhaps they re-used the hole and just drilled it deeper So many things could be going on underground (types and shapes of materials) that would make your location affected (or not) based on how the waves travel from each location. Maybe you were just better situated to dodge the waves of the second drill, or something didn't match the same acoustic resonance to be a problem.