Minister of National Revenue v. Algoma Central Highway, 68 DTC 5096, [1968] CTC 161, [1968] S.C.R. 447 -- summary under Marketing Expenditures

The taxpayer, in order to generate more traffic along a portion of its railway which ran through unpopulated lands owned by it and the Crown, commissioned a general geological survey, over a period of five years, of the mineral possibilities of those lands. In finding that the fees paid were fully deductible, Fauteux J. quoted from the decision of the Privy Council in B.P. Australia that "'it is a common sense appreciation of all the guiding features which must provide the ultimate answer'".