Nifty Sale, page-11

I'm not.

Mineral property feasibility studies- RL Bullock - SME Mining Handbook,, 2011
http://cdn.ceo.ca.s3.amazonaws.com/1b44g08-018.pdf

'Then, using good engineering judgment, experience, and cost on similar projects, the accuracy of the scoping study feasibility may be in the ±45% range. Other authors claim that an accuracy of 30% is achievable for a conceptual/scoping study (White 1997). However, this accuracy will likely not be achieved unless the project is being developed in an old district where a mine or plant has recently been built and the new installation is similar to the existing one. The 30% accuracy will only be attained after 10% to 12% of the engineering has been completed." I think you'd better add the other 20%.