Change in estimated amount of ore to be mined from year one to year 2. year 1 is 400000 and year 2 is 487500 tons. mined 50000tons in first year and mined 80,000 tons second year of which 60000 tons sold residual or salvage value of the land is $100,000. I am have problems re-figuring the depletion rate for year 2. Can you help me with this?