Business expenses are the costs of carrying on a trade or business, and they are usually deductible if the business is operated to make a profit.
While TaxAct® does not support the calculation for depletion, such as for Line 12 of Schedule C, you are able to calculate the amount and enter it in that field on your return.
Per IRS Publication 535 Business Expenses, page 35:
Depletion is the using up of natural resources by mining, drilling, quarrying stone, or cutting timber. The depletion deduction allows an owner or operator to account for the reduction of a product's reserves.
There are two ways of figuring depletion: cost depletion and percentage depletion. For mineral property, you generally must use the method that gives you the larger deduction. For standing timber, you must use cost depletion.