Summary of Task Force Meeting of October 26, 2021

This 6^th meeting of the task force was devoted to the topic of vibrations. Two WSP resource people were in attendance for a presentation: Jean-François Poulin, the impact assessment manager, and Pierre Groleau, engineer and blasting expert.

Before that, however, the meeting began with a few words from Marc-André Lavergne, Yamana’s director of Community and External Affairs. He gave the group an update on the opening of the community relations office in Évain and mentioned that a second office would soon open in the city centre to accommodate the environment, engineering and geology project teams. He listed new appointments to the Yamana team and added some detail regarding the recent article in Le Citoyen newspaper on the results of the drilling campaign in the Wildcat zone.

Pierre Groleau's main presentation provided a preliminary overview of blasting operations and the resulting vibrations. Planning such operations in an underground mine must consider the objectives of fragmenting the ore for transport to the crusher and diluting it – that is to say, the ratio of gold recovery to barren ore in the extracted ore – while controlling vibrations. An overview of the mining method planned for the project differentiated upcoming blasting to be done for development purposes (e.g., construction of tunnels) and for production purposes (ore recovery). An explanation of the standards and controls provided for by law (Directive 019 pertaining to the mining industry) and their history showed that while permitted limits were once established to protect human structures from the effects of vibrations, they are now determined with a view to limiting the effects felt in the vicinity; as such, specific standards are in place for an underground mine located less than one kilometre from private homes. Mr. Groleau also explained the leading technologies, explosives and detonators, as well as best practices for blasting, monitoring with vibration measurement equipment, and calibration and continuous improvement of the models used to design that equipment.

Following this presentation, the Yamana team explained the company's blasting tests, which would generate field data to improve the models used to forecast vibrations and impacts. Those models can employ empirical data or be adjusted based on field test results. The blasts are smaller than those done in mining, but the study of their vibration patterns in the ground produces data that allow for more accurate adjustment of the models. A discussion by the task force ensued, reiterating the need for information and advance notice, the desire to first discuss the company's commitments to the community, and the relevance and timeliness of a baseline study of properties in the area. In the end, it was decided that the tests would be postponed in order to continue the preparatory work.

The group also discussed follow-ups on incoming reports from the neighbourhood and previewed upcoming topics for discussion and consultation activities involving both the task force and area residents.

Read the full minutes of the meeting here: https://www.wasamac-consultations.com/20630/widgets/83491/documents/97731