Dear ...

Dear  ThanikachalamurthiAruchamy , Good thinking

Very risky to digging old well dumped waste the huse mass of gases like CO & CH4 will be released when digging in old well because anaerobic reaction inside and deep material. The Oxygen percentage also low. There is very difficult to survival at 60 feet depth. However, many automatic machine are available in market e.g. Vacuum excavators for digging.Vacuum excavation, or suction excavation, is the process of removing soil/debris/plastic waste etc. from the ground or removing debris from various ground locations via a vacuum hose which varies between six and 8 inches in diameter. The vacuum air inlet has a speed of up to 220 mph.The vacuum boom is guided by an operator that raises and lowers the vacuum hose to reach and suction material into the vacuum tank. Simultaneously a high pressure air or water jetter loosens the soil so that the vacuum nozzle can pick up the debris. If a rock is too large for the vacuum hose, there is enough vacuum pressure to lift the waste and place it aside.Vacuum excavation operations may either be via compressed air or high-reassure water. Either excavation method is considered best practice in locating underground utilities and reducing downtime from striking nderground utilities. Vacuum excavators will pick up virtually any kind of material such as mud, stones and pebbles, plastic waste ,railway ballast, sand, and water.

  My suggestion is you can install tube well with submergible pump this is always cheap & best. No risk at all. You can make tube well inside the old well with machine. For water charging you can dig another tube well nearby with guarded /barricaded so that any child cannot fall in tube well.

Regards,

Prem Baboo