Guidance for reporting tailings and waste rock: chapter 4

Criteria for reporting of substances

It is important to note that the NPRI substances listed in the 2009 Canada Gazette (CG) notice have not changed as a result of the addition of tailings and waste rock reporting.

A facility subject to an NPRI CG notice must consider whether the criterion for each NPRI substance is met for the year in question, to determine whether they are required to report for that substance.

1. Concentration threshold

The following concentration thresholds apply for Schedule 1, Part 1 substances: 

• Tailings: For substances contained in tailings, there is no minimum concentration threshold when determining whether the manufactured, processed, or otherwise used (MPO) threshold is met. 
• Waste Rock: For substances from Schedule 1, Part 1, Group 1, the normal 1% by wt concentration threshold applies. For substances from Schedule 1, Part 1, Groups 2, 3 and 4, there is no minimum concentration threshold.

For 2006-2008, the threshold calculation is not limited to the quantity of an NPRI substance found in tailings and waste rock. When determining whether the reporting threshold is met for a substance, the facility is required to include all of its operations/ processes in the calculation. This approach will provide greater consistency between 2006-2008 requirements and those for 2009 and onwards, where the thresholds will also be based on total quantities and is not specific to mine waste.

For 2006-2008, facilities that are subject to the CG notice would need to report on all previously reported substances from Parts 1 and 2 of Schedule 1, since they were already above the threshold before the inclusion of tailings and waste rock. As such, there may be cases where mines would need to report a “zero” quantity for disposals to tailings or waste rock management areas - if they exceeded the threshold for a substance due to non-mine-waste-related activities and therefore are required to report for that substance, but did not dispose of that substance to tailings or waste rock management areas. For substances that were not previously required to be reported, the facility would need to determine if thresholds were met for a particular year with the inclusion of tailings and waste rock, and report if needed.

Previously, for Part 2 substances, reporting was only required for quantities of Polycyclic Aromatic Hydrocarbons (PAHs) that were incidentally manufactured. As such, the criteria for reporting of Part 2 substances was expanded to cover the mining industry, specifically oil sands, which do not “incidentally manufacture” PAHs if they are already present in the bitumen, by adding “as a result of the generation of tailings” to the requirements.

Table 1 below lists NPRI substances commonly associated with the chemical composition of mine tailings and waste rock. The following list is provided for your reference only - you must consider all substances in the NPRI notices.