Oxygen influx and geochemistry of percolate water from reactive mine waste rock underlying a sloping channelled soil cover

► A channelled cover with preferential flow can still mitigate ARD to some extent. ► Oxygen ingress was more sensitive to the location of the channel than to Ks. ► The channel in the barrier layer was a major passage for O2 ingress. ► Actual flushing was an important factor when estimating O2 decay coefficient.