The mining industry is showing increasing interest in using renewable energy (RE) technologies as one of the principles of sustainable mining. This is witnessed in several pilot projects in major mining countries around the world. Positive factors which favor this interest are gaining importance and negative barrier factors seem to be less relevant. For a mine operator, the switch from fossil fuel to RE technologies is the outcome of decision making processes. So far, research about such decision making on the use of RE in mining is underdeveloped. The purpose of this paper to present a practical decision rule based on a principle of indifference between RE and fossil fuel technologies and on appropriate time management. To achieve this objective, three investigations are made: (i) a case studies analysis, (ii) a comparative cost analysis, and (iii) a SWOT analysis.