Early in the current year, Tokay Co. purchased the Silverton Mine at a cost of $18,680,000. The mine was estimated to contain 180,000 tons of ore and to have a residual value of $5,000,000 after mining operations are completed. During the year, 165,000 tons of ore were removed from the mine. At year-end, the book value of the mine (cost minus accumulated depletion) is: Multiple Choice $12,540,000 $6,140,000 $8,680,000 $13,680,000