The environmental impact assessment matrix is a simple way of summarizing which impacts are considered of greatest significance. It is a checklist or reminder of the full range of actions and impacts and is aimed at separating, as far as possible, factual information on magnitude of each type impact from the more subjective evaluation of the importance of the impact. The methodology of environmental impact analyses incorporates the principle of subjective assessment of the impacts of the separate actions which comprise the project upon various factors of the environment. The significant factors relating to effects on the physical and chemical characteristics of the northern Alberta environment as a result of potential oil sands development in the Athabasca tar sands were documented according to the \"Procedure for Evaluating Environmental Impact\" - Geological Survey Circular 645. The text of this impact report was based on the sum of magnitude and importance vectors being equal to or greater than 5 for any specific sector of the physical and chemical environment. This report and possible computer data adaptation may provide for additional summation and recommendation of specific actions incurred by oil sands development as these proposals further relate to biological and cultural aspects of the environment.