QUESTION
Is it possible to salvage a borewell in which the casing pipes started moving down slowly and muddy slush started coming up?

The possible reasons for this could be

  1. Occurrence of a layer of boulders at a depth of around 60 feet damaging the casing during drilling,

  2. Failure to properly cement the casing pipes with one another while inserting into the bore well giving scope for loose material outside the casing pipe to enter into the bore well,

  3. Failure to install the casing pipe to snugly seat into the bottom hard rock leading to its movement during drilling and consequent damaged, and/or

  4. Physical damage to the casing pipe by the drill rod during drilling.

As keeping the defunct bore well intact without sealing can lead to pollution of any new bore wells nearby, it is essential to seal it. It is also not desirable to use the defunct bore well for artificial recharge of groundwater with rooftop rainwater. How such a usage had led to discharge of water with high variation in suspended solids was discussed at https://www.indiawaterportal.org/ask/5296. It desirable to make use of the same flexible rig used earlier to remove the PVC casing pipe installed in the defunct bore well. If that is not possible, drilling at the same site can be taken up to crush the casing pipe into small pieces for removal by compressed air. Mild steel (MS) casing pipe rather than PVC casing pipe may be used for the new bore well. The casing pipe should be driven as deep as possible to a depth of 110 feet or more to snugly seat into the bottom hard rock.

R Jagadiswara Rao (https://www.indiawaterportal.org/users/rjagadiswara)

Source: https://www.indiawaterportal.org/ask/5370

by
20 July 2012