Every mine drainage district has a right to collect tolls for the use of the right-of-way, upon terms fixed by the board, which shall be the same to all parties for like services; to accept compensation for service to adjoining mines outside the district and accept revenue from all parties benefited by any use of the property, assets, or easements of the district. All funds accruing under this section shall be used to diminish the tax rate and any excess of revenue over expenses not held as a sinking fund shall be repaid pro rata to the payers of previous taxes.