In the past 50 years, the US copper mining industry has experienced remarkable changes. During the 1970s and early 1980s, the US copper mining industry suffered a major recession. However, a few companies survived by implementing severe cost-cutting measures through innovation and technological changes. These efforts, in turn, helped quintuple labor productivity in the three decades following. Then from 2003 to 2012, labor productivity declined sharply to the levels equal to those of the early 1980s. This decline, following years of rising productivity, has led to questioning the effects of innovation and technological change on mining labor productivity. It has been argued that new technology will no longer be able to offset the adverse effects of depletion thus resulting in higher prices in the future. This study investigates the determinants of copper mining labor productivity empirically, and the extent to which they may vary cyclically for longer time spans (1965 to 2015) from the US perspective. The statistical model examines the level of labor productivity as a function of copper price, recoverable copper content of ore (percentage yield), production share of leaching, mine production index, and time trend. Overall, the results support the conclusion that falling productivity is mostly cyclical.