OPM Ingredient costs required?

When using Oracle Process Manufacturing. Is it required as part of the setup, to define a cost for the ingredient items in a formula? The company I work for has quarries and mines and their raw material is derived from the land they own/lease. As such the raw material for all intents and purposes is free. The only cost that occurs is incurred during the manufacturing process of this raw material.

In addition, operating costs (such as electricity, depreciation) is only calculated at the end of a month. Which means that the cost is no realised until then. At this time, the cost is entered as a fixed single-level cost. Costs are not broken down into the different resource and overhead costs. So essentially all operating costs are added together and divided by the tonnage of product produced.