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Borewell Troubleshooting - Failure to Recover Pump: North Karnataka

The borewell is located at Hortatnal Near Koppal.  Tq.Koppal Di.Koppal Between Hospet - Gadag in north Karnataka. The bore is approximately 6.5" in diameter and dug to a depth of 293 ft. PVC casing has been put in till 20ft. Construction was about three months ago. The pump installed has now sunk by about 3 ft along with the borewell casing. Efforts to lift the same using block and tackle is not fruitful. Kindly advice on what further action is possible.

Sanjeev

bks_mms@yahoo.co.in

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Comments

1.

Dear Sanjeev,

From what you have written i imagine that your borewell is located in a terrain that has relatively high degree of jointing. The casing was installed till 20 ft as the rock as such was hard, but it is possible that the portion below was jointed and that has collapsed, probably due to the movement of water or the vibrations when the pump is in operation.

What you could do is to remove the bore cover ( if any ) and try to focus sunlight in to the borewell using a hand held mirror.

This will help you see down till about 40-50 ft. If the area near about the base of casing has collapsed ( as I assume) you will see the blockage immediately).

If this is the case then ideally one should excavate down to that level and then carefully remove the blockage at that point and then try to remove the pump.

If the blockage is not at that point and is further down, then one can pour in a small amount of detergent solution, and if the pump is installed using GI pipes the assembly should be rotated in clock wise direction to dislodge the pump.

If HDPE pipes have been used , and the pump does not have an inbuilt Non return Valve then compressed air can be passed in through the delivery pipe in an attempt to dislodge the pump.

If the pump still does not get dislodged then the whole assembly should be kept under tension over night by locking the chain-pulley block.

The other way this can be done is to use hand pump rods and a expanding tool, the tool attached to the rods could be lowered right until the pump and locked in place by expanding the tool, way a slightly more force can be applied while trying to dislodge the pump.

Best of Luck

Dr. Anil Lalwani
Well & Water Works, Pune
http://www.wellwaterworks.com

2. Pump and moter falldown in Bore

Dear Lalwani Sir

We are facing one problem, that we have a Bore 125 Mtr Deep and 200 mm Dia 30HP pump lowered in to the Bore

with the help of flanged G.I Pipes up to 60 Mtr Deep ,but after some days the one flange welding brokenout and pump fell in to bore.

Please guide properly how can we remove the pumpand motor ?

3.

Dear Sanjeev,

The query needs some more clarification. At What depth the Submersible pump was installed. Was it supplying water till its collapse or were there any intermittent drop in supply, the stop may be of a fraction of a minute to about a couple of minutes.

Further what was the discharge of the pump?

Was the discharge is higher than the capacity of the borewell yield. What is the static water level, the pumping water level and the horse power of the pump? Why only they have provided the casing up to 20 feet. How many inches of supply were reported while completing the bore well? Is there any caving in encircling the bore well?
AT present is water is pumping out from the well. Is the pump operational?

However with lot of guesses and I am analysing the cause and providing some possible remedy.

1. Since the casing has also been dragged inside, It is a total collapse of the shallow over burden. What possibly might have happen would be, at the time of drilling they might have encountered dry hard weathered rock at the top, may be with dark blackish to greenish black colour ships. Thinking that, that was the end of soft zone they might have inserted the casing.

When they started irrigating or utilizing the water in the nearby, may be paddy, or Banana or some other crop are may be storage in a paddy field, or some other activity that enriches and recharges the soil zone due continuous wetness of the soil, the pumped out water might have infiltered and slowly percolated down. Over the past three and odd months, this percolated water, near the vicinity of the bore well location might have fully saturated the weathered and soft zone.

May be because the bore well casing is not protecting the zone immediately below the bottom of the casing, the loose earth, surrounding the bore close to the casing might have caved in. While caving in it had dragged the casing also down to 3 feet level. Possibly below 23 feet, the casing again might have found a hard stratum and seated itself.

There is also possibility that they might have drilled soft zone with 9 or 10 inches hammer, beyond 20 feet and seated the 7 inches PVC pipe at 20 feet. The driller, may be due to cut and join difficulty of 3 feet length of pipe, might have, Leaving the gap of 3 feet automatically to get adjusted with the drilled powder, due to laziness provided the gap with inserting only one length of 20 feet pipe.

In due course of time, might be due to above reason described or slowly oozing of water directly between 2 inches gap of casing pipe and the parent earth, the wet drilled particles, gave way and collapsed, thus dragging the casing pipe to the drilled depth of 23 feet level. The collapsed soil got filled

The remedy may be, again the owner should contact the driller, blow out air
between the gaps of delivery pipe and bore wall. They may insert one inches dia or one and half inches dia GI pipe, instead of drill stem, and flesh out the debris by flushing the bore. Simultaneously they might engage a JCB excavator to pull the pump set. They can tie with cycle tire and pull up.

To my experience if the phenomenon is as I guessed, then the pump set will come out.

2. Secondly if the collapse is too heavy, due to various other factors, may be due to fall of more soft earth encircling the bore well zone, they can try with the flushing, as described above and lifting simultaneously with the heavy duty JCB. However care may have to be exercised not to pull out the pipe without pump set. Slow and steady apply of pressure will help to take out the pump.

With best wishes,

A. Rajamohamed Ambalam
Geophysicist
Coastal Energy Private Limited
Chennai - 600006

4.

Dear Sanjeev,

Normally one has to see the bore logs while drilling and accordingly casing has to be put. In your case no drill log was kept and it looks just 20ft casing has been done with out seeing formation log so the casing started moving downwards. You can ask the pump installer to remove the pump and study the driller's log and provide sufficient casing accordingly and then erect your pump.

With regards,

Dr. M. Thangarajan
Retired Scientist-G
National Geophysical Research Institute (NGRI)
Hyderabad

5. Muddy water in bore well- Problem with pump choice? Please help

Respected Sir,

I am a resident of Jamshedpur, Jharkhand.I have agriculture land and I have planned to build a farm where I am interested in growing vegetables. As initial preparation, I got the land ploughed, added manure to it.

For the last 7 years I have a bore well dug to a depth of 180 feet, casing 6 inches to a depth of 50 feet. While boring I remember initially I got a mixture of sand and water. After 40 to 50 feet solid black rock-like fluid was injected out along with water mixed till a depth of 180 feet. I have a hand pump installed to a depth of 50 feet and is working excellently. The water is very sweet and crystal clear.

About 3 days back I installed a Crompton Greaves make submersible pump of 1 k.w. to a depth of 150 feet. The pump is connected to the overhead tank and after starting the pump, for 1 minute clear water is pumped out. After that the pump starts delivering very dirty and muddy water and tripped in high current. Then we operated the manual hand pump and noticed that the hand pump was also delivering dirty brackish and muddy water.

After 24 hours the water from the hand pump has now cleared to a large extend.The water from the hand pump has no mud but slightly black in colour, the taste is sweet as before. The water from the hand pump can now be collected in a container and the dirt settles and can be used for drinking purpose. Please let me know what went wrong, either my selection of pump was wrong or has the bore well collapsed.

Will the decreasing of submersible pump height from 150 to 120 -100 feet help? Can installation of compressor pump help and if yes what should be the ideal depth of the suction pipe of the pump.

6. How to recover pump from tubewell - depth is 240 feet

Dear Sir,

The depth of the tubewell is 240 ft. The pump in the tube well is a GI pipe at 200 ft. I have had a problem with it from the last 6 years , but not able to recover the pump from tubewell, please suggest a way to do the same.

With regards
Anant Khongal
akhongal@gmail.com

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