For the purposes of this Part, a "mine" is—
(a) a workplace at which work is being done under a mining licence within the meaning of the Mineral Resources (Sustainable Development) Act 1990 ; or
(b) a workplace at which exploration, within the meaning of the Mineral Resources (Sustainable Development) Act 1990 , in the form of —
(i) underground work of any kind; or
(ii) drilling from the surface for coal-bed methane—
is being done under an exploration licence within the meaning of the Mineral Resources (Sustainable Development) Act 1990 ; or
(c) in relation to a tourist mine within the meaning of the Mineral Resources (Sustainable Development) Act 1990 , those parts of the mine that are underground and all infrastructure and plant associated with the underground workings; or
(d) the leased area within the meaning of the Mines (Aluminium Agreement) Act 1961 .