Any right of underground storage obtained hereunder, except in an underground storage reservoir which is a mined cavern constructed by mining operations, shall be without prejudice to the rights of any condemnee to explore for, drill for, produce, process, treat, or market any oil, gas, or other minerals which might be contained in such lands above or below the underground reservoir. Any additional cost and expense required to be incurred in order to protect the underground reservoir against pollution or escape of gas or liquefied petroleum gas therefrom by reason of boring or drilling above, into, or through such underground reservoir as provided for herein shall be paid by the public utility then owning the right to underground storage therein; Provided, no condemnee shall have the right to bore or drill into or through, or otherwise interfere with, an underground storage reservoir which is a mined cavern constructed by mining operations.