Lucky Friday is a polymetallic underground mine located in the Coeur D'Alene region of Idaho that has been in operation since 1941. The #4 shaft is expected to extend mine life to at least 2039. Board approval for the go-ahead of the project was given in 2011. The final capital cost of the project is US$225 million, of which approximately US$205 million was already spent as of December 31, 2015. The shaft reached its final depth in May 2016 and was operational by the end of the year.