Solving the Mystery of Improving Maintenance Maintenance often represents over 35% of total mine operating costs. Yet, little is known by the general mining population of the details of what maintenance does, how they do it and the help, support and cooperation they require. Many see maintenance as a ‘closed book.’ Herein are both the problem and the solution. Maintenance has done little to explain what they do, how they do it and specify the help that they need.