The assessment of base metal and gold supply are based on the years 1946-85, subdivided into decades to examine time trends. Money values are expressed in constant 1987 Canadian dollars. Appraisals are made on a potential value, before-tax basis, including all direct costs and revenues associated with exploration and development, then on an after-tax basis considering the application of federal and Newfoundland income and mining taxation systems to the overall potential values. The level and components of mining taxation are compared to other provinces and territories and base metal and gold activities are compared to those in Canada and in the Appalachian Region. The capability developed to assess the economic potential in Newfoundland is applied to evaluate and compare the impact of regional development policy options, including geologic data base development, direct assistance for mineral exploration, support for new mine development, production stage incentives, and assistance for mines faced with temporary or permanent closure.