Canadian Mining Journal


GOLD-SILVER: Iberian to patent new eco-friendly alternative to cyanide

EDMONTON, AB – Iberian Minerals has filed a US patent application for its HM x-leach, an environmentally friendly, non-cyanide leach formula for the extraction of precious metals from ore, concentrate, tailings and electronic waste.

The Iberian team developed the unique HM x-leach formula over the past 12 months and tested it successfully on samples of ores, concentrates and tailings. The final work was overseen by Met-Solve Laboratories of Langley, BC. The formula is a non-toxic, economical and effective alternative to cyanide leaching, and the HM x-leach typically had recoveries comparable to or better than cyanide.

The primary challenge in devising a suitable substitute for cyanide in gold processing, lies in developing an equally effective and degradable leach reagent, which is not a persistent environmental toxin. As gold cyanidation rates are relatively slow, the industry has been searching for faster gold leaching reactions capable of facilitating high metal recovery rates. Alternative lixiviants or leaching agents should also be inexpensive and recyclable, selective, non-toxic and compatible with downstream recovery processes, said the company in a news release.

Gold, silver and other precious metals are easily recovered from the HM x-leach solution using a number of proven methods including electrowinning, carbon adsorption and precipitation.

Iberian has create a new subsidiary, HMX Solutions, to pursue commercial opportunities for the non-cyanide method.

Visit the Iberian website at, and read the news release of July 26, 2016, for more information.