Gold cyanidation is a hydrometallurgical technique for extracting gold from low-grade ore by converting the gold to a water-soluble coordination complex. It is the most commonly used leaching process for gold extraction.

Process. Cyanide can be used to extract gold, either in a controlled mill environment, or more crudely on rock piles in the open. Cyanide “vat leaching” mixes finely crushed ore with a cyanide salt in water. The cyanide binds to the gold ions, and makes them soluble in water, thereby allowing separation from the rock.

Precious metals. The crushed ore is irrigated with a dilute alkaline cyanide solution. The solution containing the dissolved precious metals in a pregnant solution continues percolating through the crushed ore until it reaches the liner at the bottom of the heap where it drains into a storage (pregnant solution) pond.


To accurately identify minerals within tailings, geologists turn to analytical technologies including both laboratory and portable X-ray fluorescence (XRF) instruments. Portable XRF analyzers provide fast, accurate analysis of tailings to quickly and easily gauge the efficiency of extraction and enrichment processes. The real-time assay data provided by a portable XRF analyzer allows for timely process adjustments, improving productivity and reducing the need for reprocessing

  • DRD Gold, one of the first South African companies to abandon traditional mining to focus on extracting gold from tailings. New technology allows it to recover up to 40% of the gold left in particle form in tailings. DRD Gold extracted 33,600 ounces of gold, worth nearly US$40 million, in the last quarter of 2013.
  • Mintails, a mine tailings processor, has developed new technology to process 350,000 tons of slimes from its extensive tailings resources. It expects to recover 58 kg of gold per month, and has enough slimes to last until 2025.
  • Goldfields has also developed new technology for a tailings retreatment plant, and processes 12,000 tons of current tailings and 88,000 tons of old tailings a month.