We dug a borewell in Mayuri Nagar, Hyderabad. We got water at a depth of ~750ft, and we went upto 1000 ft. The borewell person advised us to go for casing pipe and he said there was some loose soil ~650. With his advise, we went for casing pipe for 1000 ft. But, while inserting the casing pipe, it did not go beyond 800ft. He said, the bottom (200 ft) got closed by itself (collapsed).
The next day morning, we did some testing. We dropped a stone which is attached with a thread. After dropping it until 685 ft, it did not go any further. He said, the bore now got collapsed upto 685ft from bottom. Now, I'm confused about what I need to do. Do I need to go for an additional borewell? Or the existing borewell will still work in the rainy season? Please advise.