Making mining equipment has been a horrible business over the last few years. The industry has been hard-hit by the spending cutbacks at mine sites around the world. For example, BHP Billiton Limited trimmed its capital exploration expenditures by roughly 70% between fiscal 2013 and 2016. No wonder Caterpillar Inc. (NYSE: CAT), Komatsu Ltd. (NASDAQOTH: KMTUY), and Cummins Inc. (NYSE: CMI) have been hurting.