How to properly seal a well

I have a well of 20 m. I want to seal it, fill the upper 10 m with concrete, and pour the lower 10 m with ASG. Do you think this method reliably isolates all kinds of sewage from entering the well?
Dean

Expert Answer

Yes, the measures described by you will be quite enough to provide the well with protection against groundwater. The only thing I would like to recommend is to use a thick clay solution instead of a sandy clay composition. This will significantly increase the waterproofing properties of the protective layer. Concrete pouring can be slightly simplified and cheapened if part of it is replaced by a sand-cement mixture consisting of 1 part cement and 5 parts sand. A carefully packed dump will petrify over time and provide perfect sealing of your well.