18.4. For the purposes of paragraph c of section 18.3, the following mean:(a) “carrying on timber business” : the whole cutting works, transformation and handling of the timber in a forest, except transportation of timber sold for delivery to a purchaser and operations of a saw mill or pulp and paper mill;
(b) “carrying on mine business” : the whole extraction-works and processing deriving from a mineral resource until the first stage of concentration or the equivalent, and includes exploitation of quarries, sand-pits and gravel-pits but not peat-bogs.