High Grade

(i) In mining, ore which is above the average grade of the mine. ‘High grading’ is used to mean that the miner is taking out too much high grade ore for a normal, balanced, long-life mining operation. Such high grading took place, for example, in Australia prior to the introduction of a tax on gold mine profits, to maximize output and profits before they were liable for tax. High grading can also mean workers in mines with very high grade deposits or nuggets, stealing chunks of rich ore; this has been a particular problem on some mines in Latin America and the Philippines.

(ii) In refining, precious metal over 800 fine, or sweeps over 200 fine.