6. Comparison of Performance of Metal Mines in 2012 and 2013
In 2013, 121 mines were subject to the Regulations compared to 117 in 2012. Four new mines became subject to the Regulations (see Appendix A for a list of mines with new regulatory status in 2013).
In 2013, 216 final discharge points were subject to the Regulations, compared with 206 in 2012.
The total number of exceedances for metals, pH and total suspended solids decreased from 74 in 2012 to 57 in 2013.
In 2013 (as in 2012), metal mines achieved a 100% compliance rate for lead. The compliance rate for copper dropped slightly from 99.8% in 2012 to 99.7% in 2013. The compliance rate for cyanide increased from 98.6% in 2012 to 99.3% in 2013. The compliance rate for nickel and zinc both increased slightly to 99.8% from 99.6% and 99.7%, respectively. The compliance rate for arsenic remained unchanged at 99.8%.
The compliance rate for total suspended solids (TSS) increased from 96.3% in 2012 to 97.9% in 2013. Although the majority of TSS exceedances reported were sporadic, five facilities seemed to have chronic TSS exceedances from at least one of their effluents in 2013; these facilities were the Williams Mine in Ontario, the Vezza Mine and the Complexe métallurgique Sorel-Tracy in Quebec, and the Elross Lake Area Iron Ore Mine and the Wabush Mines Joint Venture - Scully Mine in Newfoundland and Labrador.
In 2013, the compliance rate for non-acutely lethal effluents to rainbow trout was 96.8%, compared with 98.8% in 2012. This drop in compliance rate was partly due to an increased number of tests with mortality greater than 50% that were reported by the Vezza Mine facility in Quebec (17 in 2013 compared to 6 in 2012).
Between 2012 and 2013, a slight decrease in the percentage of tests with mortality ≤50% was observed in Daphnia magnamonitoring tests. More specifically, 93.6% of the tests showed the mortality rate was less than 50% in 2013 compared with 95.4% of the tests in 2012. In 2013, the numerous tests conducted by the Bucko Lake Mine, the Vezza Mine, the Éléonore Mine and the Ming Mine, for which the mortality rate was greater than 50%, contributed to decreasing the overall compliance rate of the sector.