To solve the problem, Minnow partnered with an aquaculture expert to create a custom onsite exposure laboratory. This innovative system allowed Minnow to perform controlled effluent exposure studies using hatchery-raised juvenile salmon transported to the mine site. The system consisted of two 1,000-liter flow-through tanks, where the fish were divided into two groups: one exposed to effluent and one exposed to reference (control) water. The tanks were carefully calibrated to ensure that temperature, flow, and other conditions were identical across both groups, with effluent exposure as the only variable.

This approach allowed Minnow to use a much larger sample size—around 150 fish—than would have been possible in the creek. A larger dataset ensured the statistical power needed to detect meaningful differences between the effluent-exposed and reference groups. The exposure period of one month was based on findings from earlier studies of presence and occupancy, ensuring relevance to natural conditions observed in the creek. Daily monitoring by the mine’s environmental team and weekly oversight by the aquaculture expert ensured the system’s reliability. Parameters such as temperature, flow rates, and fish health were closely controlled to avoid introducing confounding variables, such as temperature imbalances or disease outbreaks. At the end of the exposure period, Minnow assessed the fish for survival and growth, comparing results between the effluent-exposed and reference groups.