My neighbor is digging a bore well. The bore well contractor went for fast rigging by a lorry. But it was not successful after few hours, he advised to go for “Slow Rig” and the slow rig is digging right now and it went down upto 120 feet and the Bore well contractor says that it should hit hard rock. Thereafter the fast rig would dig the rock. My question was to him was simple - what if there was no rock? He said he was getting rock at the various levels in the ground and at a maximum of 120 feet deep.
Please clarify the following:-

1)Is there bed rock at various levels of the underground?
2)What if there is no rock at all?
3)When the digging of a bore well considered to be a failure?
4)Under what circumstances the digging of bore well should be stopped or considered to be failure?

B.Chidanand

bestchida@rediffmail.com