That sounds like a potentially toxic gas. Better get it tested first then you can have a way forward.

I will be visiting the place to ascertain what the gas could be ( through face to face interview)*. The boys have dug another 17 ft so we are at 120 ft...Problem partly overcome by leaving the hole uncovered (quiet risky) and partly swirling banana leaves continously as the digging goes. when the fumes are too strong they take a break.
Here is hoping water is struck sooner.

where can i get a small good reliable submersible pump for a well, apart from davis and shirtliff

Some updates. The diggers managed to dig upto 120ft. The 'gas' problem was overcome by leaving the well open overnight and also using banana leaves. The person digging would go carry a banana leaf with him all the way down to supply some oxygen i guess. At 120ft my resources were depleted so the digging stopped sometimes in late October (around when elnino begun). So last week my old man was checking around the well and discovered it has some water which has kept rising. The last measurement revealed 12ft of water! some good news to me.

120 ft wow those guys are not jokers, I live at the coast and I see guys here do cheaper boreholes usually 100k including the pipes the owner buys the pump and an overhead tank, doing cost coparison with how much you have used which one is cost effective, plus I have fears that guys can fall into wells not well covered, or collapsed covers.

@120 feet no water?eish huku ni wapi?

Its not vibration that killed it. The impeller must have been made of brass which is intolerant to silt. Pumps with plastic impellers perform better as they can withstand light silt without seizing. The pump should be suspended, not in contact with your wells base.

Congratulations! I know someone who uses a Pedrollo pump from a 92 foot well up to the house's water tank. Has never used a submersible pump but has had to replace the pedrolo twice in the last 8 years.

Also, I need someone to complete a well for me. The place has a bit of hard rock at some point but wells there are generally not as deep as yours. They generally get to between 60 - 80 ft. Did you encounter that hard rock?