Environment

In accordance with our Environmental Policy, we ensure an efficient use of natural resources, including water, and we assess the environmental impacts of our activities with the goal of prevention and protection.

At the Windfall Project, we use water for exploration drilling, underground equipment and at the camp.

Underground equipment uses recycled water. Groundwater pumped from the Windfall exploration ramp and runoff water from the lined waste rock stockpile are collected and treated.

Our use of water is subject to a set of environmental regulations including permit conditions and reporting requirements. We closely monitor the quality of water returned to the environment. Compliance with these laws and regulations is our priority.

Water consumption and compliance requirements are shared with the Windfall Environmental Monitoring Committee established with the Cree First Nation of Waswanipi.

Please consult our Sustainable Development Reports and Environmental, Social & Governance (ESG) Tables to learn more about our water management performance.

We avoid operating in protected areas and identified biological refuges. We respect land with special value for First Nations’ people and proceed with land reclamation once we have finished working in particular areas.

We began collecting environmental baseline data on the Windfall Project starting in 2016 with the help of our First Nations’ partners. The data helps us understand the existing ecosystem so that we can consider the affects of a future mine development at the site. By working with stakeholders, we can address concerns during the project design and commit to mitigation measures.

Our site activities consist of exploration drilling and the advancement of an exploration ramp to collect bulk samples. Therefore, the factors influencing air quality mainly relate to the emission of greenhouse gases (GHG) through fuel consumption and dust emissions. We execute our dust management plan to limit dust emitted by vehicle movement on the Windfall Project.

We calculated our GHG emissions for the first time in 2019 to give us a baseline on the Windfall Project. GHG releases from the project are estimated according to the Environment and Climate Change Canada (ECCC) GHG Emission Reporting Program (GHGRP) and the Quebec Regulation respecting mandatory reporting of certain emissions of contaminants into the atmosphere (RMRCECA).

We plan to develop GHG or energy reduction targets and we will consider GHG emissions during the project planning phase of the feasibility study and in the Environmental Assessment. Options that can have a major impact on GHG emissions include the mill location, tailings technologies, transportation routes, truck fleet composition, mining techniques and energy sources.

Please consult our Sustainable Development Reports and Environmental, Social & Governance (ESG) Tables to learn more about our energy and greenhouse gas emission management performance.

DOMESTIC AND HAZARDOUS WASTE

In accordance with our Environmental Policy, we focus on reducing the generation of waste and ensuring an efficient use of consumer goods.

Procedures are in place to store, label, segregate and properly dispose of residual hazardous materials and domestic waste, and our Environmental team regularly inspects the storage sites.

The Windfall site has a domestic waste management facility equipped with a composter and containers to sort residual material such as non-compostable domestic waste, metal and wood. We commissioned a garbage compactor for non- compostable domestic waste to significantly reduce the number of trips to landfill. The hazardous waste is stored and sorted in shipping containers with a mesh floor providing secondary containment. We store contaminated soil from accidental spills in a waterproof container for pickup and disposal by authorized companies.

Authorized companies collect metal for recycling and transport the different waste materials and hazardous wastes to designated locations.

WASTE ROCK MATERIAL

The Windfall site stores waste from the advancement of the underground ramp on a lined stockpile surrounded by ditches that direct water to our water treatment system.

When modifying our waste rock storage facilities, we characterize waste rock material and develop strategies for minimizing acid rock drainage. We design, construct and operate our waste rock storage facilities to minimize risk and impacts.

Please consult our Sustainable Development Reports and Environmental, Social & Governance (ESG) Tables to learn more about our waste management performance.

SPILL MANAGEMENT

Our employees and contractors work to prevent accidental spills and deal with any spills promptly and safely.

Our main tools to reduce impacts from accidental spills include the spill management plan, training new workers, regular inspections and enforcing on-site rules.

All new Osisko Mining or contractor workers must attend a presentation on spill management. Our spill management plan is aimed to:

• Provide readily accessible prevention and management information to workers
• Comply with federal and provincial regulations
• Comply with our Health & Safety and Environmental policies
• Minimize the environmental effects of accidental spills
• Ensure the safe and effective recovery and disposal of spilled materials.

In accordance with our Environmental Policy, we restore sites to ensure physical and chemical stability through progressive rehabilitation measures and regularly updating closure and rehabilitation plans including providing associated financial assurances.

ONGOING DRILLING ACTIVITIES

Osisko Mining follows reclamation guidelines for drilling trails and pads. This means that once we know drill pads won’t be reused for future drilling, we reclaim them in two stages:

1. Remove equipment, garbage and fuel from the drill site. Install flags on drill casings, backfill sumps, level drill pad areas and spread overburden.
2. Assess the condition of vegetation and if necessary, seed to promote regrowth.

CLOSURE PLAN AND FINANCIAL GUARANTEE

Certain exploration activities specified in the Québec Mining Act require the submission of a closure plan and financial guarantee. The closure plan and the financial guarantee must be updated every five years or when there are major changes to the project.

The Windfall closure plan includes a description of the activities and the site; protection, rehabilitation and closure measures; the closure cost estimate; and the financial guarantee. The plan also presents the closure and rehabilitation work schedule, including post-closure monitoring and emergency and temporary suspension measures.

Please consult our Sustainable Development Reports and Environmental, Social & Governance (ESG) Tables to learn more about our closure management performance.

Find out more about our reclamation approach in our Closure Plan.

Osisko Mining has initiated baseline data collection to support an Environmental and Social Impact Assessment for the development of the Windfall Project.

Environmental baseline data collection on the Windfall site began in 2016. Osisko Mining is working with the Cree First Nation of Waswanipi and the Tallymen to include Cree context and Cree traditional knowledge in each sectorial report.

We also collected baseline data on the human environment, holding focus groups with elders, youth and women in the Waswanipi community and the city of Lebel- sur-Quévillon. We organized interviews with land users, community and city representatives and various local organizations. These meetings were an opportunity to explain the project and get valuable input on the project design from stakeholders.

Osisko Mining also organized Open Houses in Waswanipi, Lebel-sur-Quévillon and Windfall to share our Project Description Report, our plans and assessments, to explain regulatory procedures and to invite feedback. A video was produced to explain the Project Description Report and it is available in Cree, French and English.