Waters + extractive residues
Acid mine drainage, metal-laden water, tailings seepage and processing residues.
Water moving through a mine picks up what the rock holds. Acid mine drainage carries iron, aluminium, zinc, copper and arsenic out of the workings. Tailings seep. Processing plants produce residues with the same metals in them. Closed and legacy mines keep producing water long after the last tonne of ore, and discharges are controlled under the Resource Management Act with limits set against water quality guidelines.
Operating and closed mines
Quarries and aggregate processing
Crown and council owned legacy mine sites
Tailings facilities and processing plants
Lime dosing and long-term treatment plants. The water is dosed to raise pH and drop the metals out as sludge, which then needs its own pathway, usually a Class 1 landfill under the waste disposal levy. The plant runs for as long as the water does. For a closed mine that can be decades of operating cost against no revenue.
Metals are separated and concentrated. Water is verified. Regen deploys to the site and treats the water where it is produced, so the metals leave as a small, defined concentrate instead of a growing sludge pond. The water is tested against the discharge limits by an independent laboratory, and the report is written for the consent file.