Waterbodies Significantly Affected by Discharges
The Red Lake mine discharges a quantity larger than 5% of the receiving waterbody, Balmer Lake. Balmer Lake is a small headwater lake which drains south into the Chukuni River and eventually into Keg Lake. There are no known negative impacts related to effluent quality from the current mine discharges. Environmental monitoring in Balmer Lake has indicated significant improvements in its water quality and overall biological health in recent years.
At Cerro Blanco, treated and discharged mine water is in compliance with the appropriate regulatory conditions. Water is discharged into a waterbody that is a tributary to the Ostua River and eventually to the Laguna de Guija, which is a lake shared by both Guatemala and El Salvador. In Guatemala the lake is not identified as a Ramsar site (of "international importance" under the Ramsar Convention). In El Salvador, however, the Guija general area, more than 10,000 hectares which includes the lake and surrounding wetlands, was declared a Ramsar site in 2010.
Consistent with our best practices for environmental management, we pay careful attention to the discharge water quality to ensure there are no negative impacts to the Laguna de Guija. Cerro Blanco’s water treatment facility ensures that any water taken from the underground exploration workings is treated properly prior to discharge. In addition, the water quality monitoring program at the site includes regular monitoring of water quality for surface and underground water as well as monitoring of other important parameters such as aquatic fauna (including fish, macro and micro invertebrate surveys). The monitoring data is submitted regularly to the authorities, and periodic site inspections are conducted.