Submarine tailings disposal (STD) for mines: an introduction

The basic submarine tailings disposal (STD) design consists of a tailings line to a deaeration / mixing chamber, with a seawater intake line, and discharge to location and depth allowing gravity flow of a coherent density current to final sedimentation area. Such STD systems can place mine tailings at locations and depths constraining environmental impact to (1) restricted areas of seabed, and (2) deep water turbidity. At some coastal and island locations, STD provides a tailings disposal option that can haue less cumulative environmental impact than the alternatives of disposal to pit, surface (dam impoundment), or river or lake. There needs to be minimal risk of tailing suspension, or resuspension, and upwelling to surface waters. The potential for these risks can now be calculated by modeling procedures. An STD system has been operating at Island Copper Mine, Canada, since 1971, with only minor environmental and technical problems involving irregular resuspension events, maintenance of the system, and ...