JOHANNESBURG (miningweekly.com) – Chesapeake Gold plans to use desalinated seawater from the Pacific coast to supply water for its 100%-owned Metates project, in Durango state, Mexico.
“Besides the economic benefits, desalination decouples the water supply and demand for Metates. 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,” Chesapeake president Randy Reifel explained on Friday.
Through an updated prefeasibility study, the gold miner determined that for Metates' 30-year mine life, desalination provided a cost effective, reliable and responsible water supply solution, as opposed to water from the Mexican national water agency Conagua, which had increased the 2015 consumptive water rates by about 100%.
“Sea water reverse osmosis (SWRO) water is projected to have lower overall capital and operating costs compared with conventionally sourced surface water. A reliable and long-term water supply at a manageable cost is critically important to projects such as Metates,” the company said in a statement.
Several large international companies with experience in the construction and operation of SWRO desalination plants had been approached and a tender process was initiated for proposals to supply about 20-million cubic meters of desalinated water a year.
“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.
From a stakeholder and environmental perspective, desalination would not compete or conflict with the expanding demand from surface water users in the region during Metates' mine life.
The proposed SWRO plant would be located within the same hydrologic basin and irrigation district as the existing surface water users, which would simplify stakeholder water transfer and trade agreements.
The primary water-storage reservoirs for the Metates mine site and the off-site processing location could also now be relocated closer to nearby larger drainage basins.
“Water supply from the larger drainage basins system significantly reduces the size of the required storage reservoirs and environmental footprint,” Chesapeake noted.