Implications of Non-Acidic Metal Leaching on Mine Rock Management at a Nickel Mine in Permafrost Terrain: Environmental Baseline Investigation

• Main Authors: R. V. Nicholson, Michael J. Rinker, M. A. Venhuis, G. Williams, B. Swarbrick
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Copper Mine; permafrost
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.588.8973; http://www.techtransfer.osmre.gov/NTTMainSite/Library/proceed/sudbury2003/sudbury03/111.pdf

Raglan is a nickel-copper mine in the continuous permafrost region of Quebec that commenced operations in 1997. The potentially-acid mine rock was being stockpiled for later backfill of open pits to freeze in-place for permanent storage, while non-acid generating mine rock was stored on surface permanently. However, it has recently been recognized through laboratory and field investigations that nickel leaching occurs for certain rock types that were considered to be non-acid generating. The pre-existing screening criteria were reexamined to address the issue of nickel leaching and cut-off criteria for reactive waste. The more conservative criteria resulted in a significant change in mine plans to dramatically reduce the quantity of mine rock for the project. In addition, a baseline assessment of the mine claim areas was initiated to better define conditions in areas of planned open pits. Natural levels of nickel in the region are elevated but actual values are watershed specific. Surface water quality is now routinely monitored and nickel loadings are evaluated by sub-watersheds to identify pre-mine and mining operations effects. The results of three years of monitoring are summarized.