Thank you for the question.
Without knowing all the facts and subject to a final audit by the Canada Revenue Agency, here is my take on the situation you have just described.
In the case of flights organized by a mining company strictly for revenue generation purposes and for transporting people from one site to another, the clauses were written in such a way so that these flights would be eligible for an exemption. A mining company that buys an aircraft which would normally be taxed would be able to obtain an exemption certificate in order to avoid paying the tax.