Barrier put in mine that sent toxic water into 3 states – by Dan Elliott (Montreal Gazette – September 20, 2017)

THE ASSOCIATED PRESS – DENVER — The U.S. Environmental Protection Agency is installing a barrier and valve inside an inactive Colorado mine to prevent another surge of wastewater like a 2015 blowout that contaminated rivers in three states.

The 12-inch (30-centimetre) valve will regulate wastewater pouring from the Gold King Mine in the San Juan Mountains of southwestern Colorado, where the EPA inadvertently triggered a wastewater spill while excavating at the mine entrance in August 2015.

That spill released 3 million gallons (11 million litres) of wastewater containing aluminum, iron and other heavy metals and instantly became a major embarrassment for the EPA.

Rivers in Colorado, New Mexico and Utah were tainted. Irrigators, water utilities and rafting companies temporarily stopped using the Animas and San Juan rivers. The EPA says water quality quickly returned to pre-spill levels.

The valve will be mounted in a steel-and concrete barrier about 70 feet (20 metres) inside the mine. The barrier will have water-tight access doors so workers and equipment can get deeper into the mine for cleanup and investigation.

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