Colo. Rev. Stat. § 34-44-104
In said accounting, the working tenant shall be permitted to set off against the proceeds of such mining operation all expenditures and expenses of said work, including: The building and repairing of such roads, whether public or private, as are necessary or expedient to furnish economical transportation to mill or reduction works or railroad; prospecting, development work, and mining, including openings and appliances for ventilation and drainage, and dead work generally; the purchase, installation, maintenance, and operation of tools, machinery, equipment, and appliances for prospecting, developing, and working the mine, and of transporting ore and products, and all other expenses reasonably incident to or arising out of such mining operation. In said accounting, the working tenant shall be allowed setoff for the reasonable value of his service actually rendered in or upon the operation, but the amount of compensation shall not exceed the current rate of wages or compensation for work of like character in the community in which said mine is situate, and shall also be allowed setoff for his expenditures and expenses in prospecting unless it clearly and convincingly appears that said prospecting was done in bad faith with willful intent to injure or defraud the nonworking tenant.
C.R.S. § 34-44-104