We have drilled borewell upto 575 ft through sensor vehicle and used filter pipe and yet at 300ft it has been collapsed when checked through camera testing. However, at the same site we drilled  upto 73ft and installed 10" pvc pipe and drilled upto 155ft through inwell bed setting and found 3 layers of loose soil and kept covering the borewell.So what should we do now for a successful drilling?