help please

In January, 2020, Sheridan Company purchased a mineral mine for $4800000 with removable ore estimated by geological surveys at 2400000 tons. The property has an estimated value of $320000 after the ore has been extracted. The company incurred $1600000 of development costs preparing the mine for production. During 2020, 600000 tons were removed and 450000 tons were sold. What is the amount of depletion that Sheridan should expense for 2020? $1440000 $840000 O $787500 O $1140000