Complete the Table below, assuming a profit allowance of $3.00 per tonne. Then, assuming a stripping cost of $2.00 per tonne of waste and a copper price of $3.63 /lb, calculate the economic stripping ratio (SR_e) for each of the copper head grades. Also, calculate the cutoff grade for copper prices of $3.40/ lb and $2.10/ lb. Show your calculations. -- Note: Head grade is a general term referring to the grade of ore delivered to the processing plant. Since the broken ore comes from various sections of a mine, the ore accepted at the Mill/Processing plant consists of a blend of various ore grades. Therefore, the term head grade or simply head is commonly used in the plural form, i.e. head grades or heads. (20 points)

0.92 91 0.87 89 0.75 85_ 0.68 82 0.55 78_ 0.43 66 T T T T T Heads % Cu % Rec'd Rec'd Cu (Kg/tonne) Value of Ore ($/tonne) T Costs ($/tonne) Mining - Milling Others (Depr, etc.) Total Prod. Costs ($/tonne) Profit Allowance ($/tonne) Total Cost ($/tonne) 6.00 6.00 6.50 5.00 6.00 6.50 | 5.00 6.00 6.75 5.00 6.00 6.00 6.75 17.00 5.00 5.00 750 500l 5.00 Net Value ($/tonne) Stripping Costs ($/tonne) Economic Strip ratio 0.92 91 0.87 89 0.75 85_ 0.68 82 0.55 78_ 0.43 66 T T T T T Heads % Cu % Rec'd Rec'd Cu (Kg/tonne) Value of Ore ($/tonne) T Costs ($/tonne) Mining - Milling Others (Depr, etc.) Total Prod. Costs ($/tonne) Profit Allowance ($/tonne) Total Cost ($/tonne) 6.00 6.00 6.50 5.00 6.00 6.50 | 5.00 6.00 6.75 5.00 6.00 6.00 6.75 17.00 5.00 5.00 750 500l 5.00 Net Value ($/tonne) Stripping Costs ($/tonne) Economic Strip ratio