RE: How I get 0.02 - TobyMy calculation is:
70.5 grams per 1000 kg of concentrate (tonne)
6000 kg of concentrate contains 70.5 * 6 = 423 grams gold.
The original resource was 19,200 kg or 19.2 tonnes.
423 grams/19.2 tonnes = 22 grams per ton ore resource.