The firm mined 93,624 ounces of the yellow metal in the three months to end September and it also maintained its full-year production forecast of 420,000 ounces of gold.
Figure is based on preliminary assessments of the damage caused to water, flora, fauna, and wildlife, as well as official information on water quality.
A proposal that the Swiss National Bank should hold a fifth of its assets in gold and be prohibited from selling the precious metal in the future would severely restrict its ability to conduct monetary policy, the WSJ reports.