Overview

Barrick Cortez Inc. (Cortez) has retained Linkan Engineering to develop and evaluate treatment alternatives for designing a water treatment plant to treat Cortez Hills Underground (CHUG) dewatered water at the Cortez Hills Mine. Currently, permitted mining of the Cortez Hills deposit is expected to require dewatering at annualized-average rates up to approximately 8,500 gpm. Dewatering is currently accomplished using a combination of surface dewatering wells and underground drainage galleries. Recent changes to permit requirements, along with investigations of groundwater quality in 2011 and 2012, have indicated elevated arsenic concentrations that are anticipated to require water treatment in order to meet the stipulated water-quality guidelines for infiltration and irrigation. During feasibility-level studies associated with future mining activities, Cortez identified water treatment using ferric addition and precipitation as the proposed method to address the water-quality concerns.

Linkan staff conducted bench and pilot testing and concluded that the best arsenic and antimony removal technique appeared to be a combination of chemical pretreatment using ferric adsorption followed by MF membrane filtration. A key design success was the determination of the “sweet spot” whereby arsenic adsorption and removal was maintained while lowering the feed pH to adsorb the antimony. Executing this two-contaminant removal in a single step cut capital costs in half.

Project Highlights
  • 2,500 gpm
  • Removal of As, Sb, Fe, and Mn
  • 7,500 foot pipeline
Project Duration

2013

Linkan’s Role
  • Process Development
  • Bench Testing
  • Pilot Testing
  • Detailed Design
Reference

Mr. Casey Lee
Project Manager
Barrick Cortez Mines
775.468.4863

Project Features

  • Feed flow rate of 2,500 gpm
  • Ferric chloride addition for Arsenic adsorption
  • Simultaneous Arsenic and Antimony removal by pH adjustment
  • Microfiltration to 0.1 micron particle size
  • pH/ORP adjustment using Hydrochloric Acid and Sodium Hydroxide
  • Solids thickening with plate and frame press (2,500 dry lbs per day)