Development of a simple segregation program to manage potentially acid generating waste rock at the Keystone Gold Mine, Manitoba

CIM Bulletin, Vol. 93, No. 1037, 2000

D.H. Flather, Lorax Environmental Services Ltd., Vancouver, B.C. K. Drover, Keystone Gold Mine, Lynn Lake, Manitoba J.W. Hendry, Black Hawk Mining Inc., Toronto, Ontario

Black Hawk Mining Inc. has completed a comprehensive program on the prediction and management of acid rock drainage (ARD) at their Keystone Gold Mine (Keystone) near Lynn Lake, Manitoba. The program, initiated in 1994, followed a phased approach utilizing initial acid-base accounting (ABA) results and subsequent laboratory kinetic testwork to define site-specific sulphide oxidation and neutralization consumption rates in waste rock. Net acid generating waste rock at Keystone was defined through the kinetic testwork as waste rock yielding a net potential ratio (NPR) of less than two. A preliminary waste rock management program based on blending of potentially acid generating and acid neutralizing waste rock was advanced. Subsequent refinement of the management program followed the analysis of over 1580 ABA samples collected from individual blast holes during the initial bench development phase of the Keystone pit. Uncertainties in actually achieving adequate blending within the dumps at a mining-scale resulted in the development of a revised waste rock management program based on segregation. Rec

Keywords: Acid rock drainage, Keystone Gold Mine, Acid-base accounting.