- The mine opened in 1877 and closed in 1975, when Phelps Dodge stopped mining operations in Bisbee
- It reopened in 1976 as a tour for visitors
- The mine has seven levels with 143 miles of passageways
- The mine's ore-body is 23% copper, which is a very high grade
- The mineralization is high-grade copper carbonates with minor lead zinc and carbonates