The Kidd Creek massive sulfide deposit is one of the world’s largest and highest grade Cu-Zn deposits, with total past production, reserves, and resources to the 9,800-ft level (2,990 m) of 170.9 million tonnes (Mt). The discovery hole, K55-1, was drilled in 1963 and encountered ore at a depth of only 7 m. It intersected 190 m grading 1.21% Cu, 8.5% Zn, 0.8% Pb, and 138 g/t Ag. The deepest ore intersection at 10,200 ft (more than 3,100 m) cut 442 m of mineralization with an average grade of 1.16% Cu, 7.8% Zn, 0.73% Pb, and 84 g/t Ag, remarkably similar to the very first ore intersected 44 years earlier and nearly 3 km above the bottom of the mine. After 50 years of continuous mining (1966–2016), the deposit has produced a total of 140.4 Mt of ore at grades of 2.29% Cu, 6.15% Zn, 0.22% Pb, and 86.2 g/t Ag, worth an estimated US$50 billion. The contained metal (3.8 Mt of Cu, 10.5 Mt of Zn, 0.38 Mt of Pb, and 12.7 million kg of Ag) accounts for nearly one-third of all metal in Archean Cu-Zn massive sulfide deposits worldwide. At the time of writing, production had reached a depth of 9,500 ft (2,896 m), and because of the remarkable continuity of both the tonnage and grade, mining below 9,800 ft (2,990 m) is now being planned to increase the mine life to 2021. It is currently the deepest base metal mine in the world, and after more than 1.8 million meters of drilling (1,800 km), the deposit remains open at depth.