What the Bedrock Samples Tell Us About Safety
If you have spent any time in the bush around Northwestern Ontario, you know that the rock beneath our feet is the foundation of our landscape. For residents in Melgund Township, Borups Corners, and Dyment, understanding that rock is about to become much more important. The Nuclear Waste Management Organization (NWMO) has released technical data regarding the geochemistry of the rock at the proposed Revell Site. This is a critical part of the Impact Assessment for the Deep Geological Repository, as it determines whether the millions of tonnes of rock they plan to dig out and store on the surface will be safe, or if it poses a risk to our local water systems.
What We Are Learning
The NWMO has been drilling boreholes to pull up cylinders of rock, known as core samples, to see what the geology looks like deep underground. Their initial report suggests that the rock is 95% "granodiorite-tonalite." In plain English, this is a very hard, granite-like rock that doesn't soak up much water (low porosity). Crucially, the report claims this rock does not contain significant amounts of sulphur. This is good news on paper because sulphur in waste rock is what causes "acid rock drainage"—a chemical reaction that turns rainwater acidic and can leach heavy metals into nearby creeks and lakes.
The Reality Check
While the initial description sounds promising, we need to look closer at the difference between what is being promised and what has actually been proven.
- What is being promised: The proponent claims the rock is "non-acid generating" and won't harm the environment once it is dug up and piled on the surface.
- What we need to verify: These confident claims are based on only six boreholes and about 100 samples. For a project of this massive scale, that is a very small snapshot. Furthermore, the report admits that the long-term "kinetic testing"—the tests that actually simulate how the rock behaves over years of exposure to rain and air—is still "underway." They are anticipating good results, but the data isn't fully there yet.
The Path Forward
To ensure the safety of our watershed, we need to close the gaps between assumptions and hard data.
The report noted that the assessment relies heavily on the density of the solid rock (matrix porosity) to claim safety; therefore, we are calling for a much deeper analysis of the fracture networks. Water doesn't usually flow through solid granite; it flows through the cracks. If the safety case ignores these fractures, we aren't getting the full picture.
Additionally, the report noted that definitive conclusions about acid runoff were drawn before testing was finished; therefore, we are calling for the Impact Assessment to be paused until the kinetic testing is 100% complete and peer-reviewed. We cannot accept "anticipated" results when the health of our local environment is at stake. We also need to see a sensitivity analysis on that 5% of "other" rock types found in the samples to ensure no hidden pockets of bad minerals exist.
Why It Matters Here
For those of us in Melgund Township and surrounding areas, this isn't just about geology; it's about lifestyle. If the waste rock pile at the Revell Site generates acid runoff, it flows downstream. This impacts the fish we catch and the water quality that supports our hunting grounds. Furthermore, if the rock underground has more fractures than the core samples suggest, it changes the safety calculations for how well the repository can contain nuclear waste over thousands of years.
Have Your Say
This affects our future. Submit your feedback on this specific issue via our Engage page to ensure the Impact Assessment Agency hears from our community.
The Melgund Integrated Nuclear Impact Assessment Project
The Impact Assessment Agency of Canada (IAAC) is reviewing the Nuclear Waste Management Organization’s (NWMO) proposed Deep Geological Repository (DGR) at the Revell Site, located near Ignace and Wabigoon Lake Ojibway Nation in Northwestern Ontario.
This major nuclear infrastructure project is undergoing a joint federal review by the IAAC and the Canadian Nuclear Safety Commission (CNSC) to evaluate environmental, health, social, and Indigenous rights impacts over its projected 160-year lifecycle.
Public Feedback Open: Comments on the Initial Project Description are accepted until February 4, 2026. Submissions help shape the formal impact assessment guidelines.
This short article and summary is based on an initial analysis of a proponent’s initial project description. It does not represent, any community the NWMO or the Government of Canada. Learn more at the Melgund Integrated Nuclear Impact Assessment Project project page.
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