Rio Tinto Mine dewatering and Irrigation Project – Saline Water Managment

NewFields was a consultant for British-based Rio Tinto Mining Company and its subsidiary, Resolution Copper Mining near Phoenix, Arizona. The project focuses on the blending of saline mine water with Central Arizona Project water for irrigation of cotton, alfalfa, sorghum and sod. NewFields is leading an effort to create an acceptable blended water quality for irrigation on approximately 7,000 acres of agricultural land within the New Magma Irrigation and Drainage District. This project involves direct working efforts with the United States Bureau of Reclamation, the state of Arizona Lands Department, New Magma Irrigation and Drainage District, the University of Arizona Soil, Water and Environmental Science Department, Rio Tinto and the Resolution Copper. Many of these multi-stakeholder efforts were for the purpose of obtaining permitting documents and satisfying the discharge requirements. The project involved real-time monitoring of treated mine water, Central Arizona Project water, and the blended water quality and quantity.

The network monitors in-canal Total Dissolved Solids (TDS), temperature, and pH probes. A web-based portal and mapping application was used for instantaneous water quality assessment and tracking. NewFields also manages a comprehensive soil, water, and tissue sampling program that will take place at least quarterly for the expected 3- to 4-year project duration. Crop growth stages and tracking will also be conducted. After it is dewatered, this mine will be the largest copper mine in North America.