Leachate from a well-instrumented experimental-scale waste-rock pile (test pile) at the Diavik Diamond mine, Northwest Territories, was monitored. The well-characterized waste rock consists of granite, pegmatitic granite and biotite schist with an average total sulfur and carbonate carbon concentration of 0.053 and 0.027 wt.%, respectively. The leachate emerging from the southern basal drain of the waste rock pile has been monitored since 2007. The zinc stable isotope footprint was characterized alongside standard monitoring parameters during two field seasons, May to November 2011 and 2012. The pH ranged between 4.3 and 6.8 and carbonate alkalinity was low or undetectable (