Deep Hole Construction Technology for Polymetallic Mine in Complex Formation of Changbai Mine Area
Because of the complex formations, deep hole drilling is very difficult in Changbai polymetallic mine area. The advanced borehole structure and wire-line coring drilling were adopted; with wire-line coring pipe of the same diameter as the intermediate casing; high performance PAB solid-free flushing fluid and the drilling technology with high-level broad spectrum bit were selected. A borehole of