High Grade / Grading / Grader

High grade refers to a higher than average grade of ore.

High grading occurs when a mining company extracts only best quality ore.  The problem
with this type of extraction is that once the quality ore is removed, all that remains
is a lower grade.  This could reduce the life of the mine if the lower grade ore becomes
uneconomical to extract.

With respect to refining, the term 'high grade' generally refers to grades over 80% or 800 fine
and sweeps greater than 20% or 200 fine.

High grader is a term used to describe a person who steels rich ore from a gold mine.