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 extracted from a mineral property by mining, drilling, quarrying stone, or cutting timber. The depletion deduction allows an owner or operator to account for the reduction of the mineral property’s value or basis as a result of the extraction of the natural resource.
There are two ways of figuring depletion: cost depletion and percentage depletion. For oil and gas wells, mines, other natural deposits (including geothermal deposits), and mineral property, you must generally use the method that gives you the larger deduction. For standing timber, you must use cost depletion.