An understanding of the breakdown of mine costs is an important tool for researchers and developers who seek to place novel cost-reducing unit operations in the wider general cost context. This paper provides a breakdown of operating costs in 63 mines by dividing them into three main categories: mining, milling, and general and administrative (G & A) costs. The study looks at patterns in mining type, mill processing type, mineral type, and the differences between costs expressed in feasibility studies vs. operating mines. The paper explores the reasons for the relationships observed and then presents a total average mine cost breakdown. It was found that the mean relative mining and milling costs did not differ significantly, and that on average they had equal shares of the total enterprise operating costs. Effects of mine and mineral type were observed, with underground milling costs being significantly less than open pit milling costs and gold mines occupying a significantly larger share of mine operating costs than copper-containing mines. The overall relative operating costs were found to be in the ratios between (43:43:14) and (45:45:10) (Mine:Mill:G & A). A treatment of potential unit operations and innovative technologies is provided at the conclusion of the paper, including coarse particle recovery by flotation and novel grinding technologies. (C) 2013 Published by Elsevier Ltd.