The key differences between a scoping study and a feasibility study have to do with:

•stage of the project -- scoping study is limited to early stage projects

•usage of inferred resources -- a scoping study, with strict disclosure requirements, may use inferred resources. A feasibility study would be restricted to Proven and Probable reserves plus Measured and Indicated resources.

Involving the difference between Proven and Probable Resources and Measured and Indicated Resources, etc... the best article I've read is by a guy named Mickey Fulp. I met him in New York a few years ago. He's an interesting character, and I can't say that everything he has written I always agree with. This piece, however, is easily the best article written by anyone explaining what all this geologist-speak stuff means in plain English.

Here's the link:

http://www.mininggeologist.com/mercenary_musings/musing-080825-Reserves-and-Resources-A-Primer-for-the-Lay-Investor.pdf