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Questions

What is the commonly used method for drilling borewells in Bangalore?
It is the normal practice to drill 6½-inch bore wells in the hard rock areas of Bangalore with blank casing installed deep into the hard rock and no casing pipe at all beyond that depth so that only clear water free of turbidity enters the well from one or more water-bearing fractures within hard rock.
bala  posted 6 years 11 months ago
Questions

Sand encountered while drilling a borewell in Bangalore. What are the implications to the borewell?
The driller probably reached this sandy layer after pinching out a hard clay layer and sand was coming out below the clay roof. Then its better not to put the strainer and keep it open at the bottom of the well so that it would behave as a Cavity type Well.
bala  posted 6 years 11 months ago
Questions

The only space for drilling a borewell in a house site is the parking area with a 10 ft roof. How to drill a borewell here?
The geology of Bangalore is such that bore wells can be drilled by using Down-The-Hammer (DTH) rigs requiring several tens of feet space for up-and-down vertical movement of the drilling shaft. The space of 10 feet available between the ground level and the roof of the parking area is too small for taking up drilling.
bala  posted 6 years 11 months ago
Questions

An open well close to a building has only 3 ft wide space to access it. Can a bore well be dug inside the open well?
Next to the open well, one can drill a 4” diameter borewell, with compressor fitted stand drilling rig. In that case, it is not necessary to take the rig very close to the point of drilling. But you can drill only upto 250-300 feet using this method. Inside the openwell, drilling is not required as there would be lots of management issues in future.
bala  posted 6 years 11 months ago
Questions

A borewell dug 3 yrs ago to 500 ft with water available at 470 ft. Any options to increase the water source in the borewell?
The best course of action would be to find out a local pump supplier who can test your borewell and install a suitable pumpset that discharges enough water. If enough water does not come out, then you lose only the testing charges. If enough water comes out, then the pump supplier will be able to sell you a pump set besides collecting testing charges.
bala  posted 6 years 11 months ago
Questions

One borewell is connected to another 6 ft away contaminated from sewage lines passing nearby. Any suggestions?
The contamination will move towards the new borewell also as there is a direct linkage which was established while drilling itself. More over 6 ft is not enough distance to ensure clean water.
bala  posted 6 years 11 months ago
Questions

A 20 ft pipe connected to a pump has fallen into the borewell. Is it possible to retrieve the pipe?
Due to wear and tear or corrosion, the falling of pipe and motor is quite common in bore wells. The bore well companies and pump mechanics have special tools to fish out the same. Kindly contact a pump mechanic's shop, pump/motor selling shop or pump distributor. They will have the list of such specialist mechanics who can fish out the pipe and revive the bore.
bala  posted 6 years 11 months ago
Questions

I am having trouble with my borewell. Is there any tool that helps me diagnose what the issue is and what action to take?
Please refer to http://coffee-table.4894995.n2.nabble.com/file/n4942112/Borehole.xls sheet which has a table that facilitates self-diagnosis. It also lists various factors that can affect borewell performance and parameters that can be monitored.
bala  posted 6 years 11 months ago
Questions

Is there any way to remove a small object blocking a borewell just below the casing pipe depth? Will taking video footage help?
Some rock from the uncased portion of the bore must have caused the obstruction.
bala  posted 6 years 11 months ago
Questions

When and to what depth should the inner casing be laid for a bore well?
If there was loose and friable material encountered at the depths mentioned where one struck small quantity of water then one should install the inner casing all the way down to the depth at which water was finally struck. It will prevent the fine sand etc. from entering into the well, filling up the borewell and jamming the pump.
bala  posted 6 years 11 months ago

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