### Calculation of Ore Tonnage & Grade from Drill hole

Jan 21, 2016· MINERAL ORE RESERVE Case 1. When all holes have positive values, let a, b and c, be the depth of ore in the three holes forming the prism; to find the average depth of the ore influenced by any given hole, use the formula d = 4a + b + c/6. Then, as one proceeds from hole to hole, b and c should be substituted, thus 4b + a + c/6 and 4c + a + b/6,