Gold miner opts for desalination to supply planned Mexican mine

The gold mining arm of energy firm, Chesapeake, has opted to use desalinated seawater to supply water for its proposed Metates gold and silver mining project in Durango state, Mexico. It has tendered for proposals to build and operate a 55Ml/d desalination facility to supply the mine with fresh water.

Chesaspeake Gold concluded that seawater desalination was the best source of water for the 30-year lifespan of the proposed mine. This decision followed its review of a 2013 prefeasibilty study after Mexico’s water agency, Conagua, doubled the price of water this year. “Seawater reverse osmosis (SWRO) water is projected to have lower overall capital and operating costs compared with conventionally sourced surface water.” the company said in a statement.

Chesaspeake Gold found that desalination of water from the Pacific offered a cost effective, reliable and sustainable water supply compared to taking water from Conagua. “Besides the economic benefits, desalination decouples the water supply and demand for Metates,” said Chesapeake president Randy Reifel in a release.

The proposed SWRO plant would be located within the same hydrologic basin and irrigation district as current users of surface water. Chesapeake said this would simplify water transfer and trade. “In the event of a possible drought, desalination can supplement water for mine operations and surface water consumers in the same basin. Desalination will also reduce the project’s environmental impact which benefits eventual mine closure and reclamation,” Reifel said.

Chesapeake said it had approached “Several large international companies with experience in the construction and operation of SWRO desalination plants” and a tender process was initiated for proposals to supply desalinated water at about 20 million m³ a year.

The design, engineering and costing of two proposed storage reservoirs is close to completion. The updated prefeasibility study will be available in the third quarter of 2015.

“The natural gas pipeline under construction down the northwest coast of Mexico and proposed dedicated gas-fired power plant for Metates contributes significantly to the economics of SWRO,” the company added.