Certain interests in land present particular problems for which there are special compensation procedures. The rules of compensation dealt with so far in this part of the book must therefore be considered subject to these procedures, where applicable. When land is compulsorily acquired, any minerals it contains will pass to the authority. Compensation for the land should reflect the value of those minerals, although their full value will depend upon the availability of planning permission to extract. Statutory undertakers include the bodies running railways, road transport and water transport; or responsible for canals, docks, harbours, piers or lighthouses; or supplying electricity, gas or water. The normal rules of compensation apply: if necessary, the statutory undertaker can claim compensation for the cost of reinstatement, at the Lands Tribunal’s discretion. A mortgagee has an interest in land and is entitled to a notice to treat.