Given the cost and the expected harvest, therefore the depletion cost per ton of ore is:
Depletion cost per ton = $500,000 / 1,000,000 tons
Depletion cost per ton = $0.5 / ton
Since during that year, harvest is 350,000 tons of ore, therefore:
Depletion cost that year = ($0.5 / ton) (350,000 tons)
Depletion cost that year = $175,000
Therefore, the entry should be:
A debit to Depletion Expense for $175,000