Gramalote: Grade Engineering Pre-Feasibility Study Review

Anglo Gold Ashanti (AGA) has completed a bulk test work campaign aimed at confirming metal deportment responses observed in variability testing on broken ore at near run-of-mine fragmentation distributions at its Gramalote project.

This article was published in CRC ORE News - June 2017

Gramalote: Grade Engineering Pre-Feasibility Study Review

By Dr Greg Wilkie; CRC ORE Program Coordinator, Program 1: Define

gramalote siteAnglo Gold Ashanti’s Gramalote deposit in Colombia.Blasted samples underwent Grade-by-Size deportment characterisation and progressive crush testing to quantify the metal deportment response relative to changes in particle size distribution.

This work follows on from initial Grade Engineering® studies at the Gramalote deposit which indicated that significant value could be obtained by exploiting natural grade by size deportment. The site’s gold response rankings were consistently amongst the highest seen in CRC ORE testing to date.

In February 2017, AGA engaged CRC ORE to conduct a review of the Grade Engineering® data obtained from this bulk test work program. The primary focus of the project was to review and analyse all bulk testing results, and provide recommendations on the application of Grade Engineering® at Gramalote with a definition of work required as part of a feasibility study.

The key activities conducted in the project were:

  • Review and analyse all Grade Engineering® data collected as part of the Gramalote PFS study.
  • Identify any risks associated with Grade Engineering® application at Gramalote.
  • Investigate the limits of Grade Engineering® for the site.
  • Investigate opportunities for the application of Surge Slave Separator (working title) and conduct a trade-off study between Surge Slave Separator (working title) vs Fixed Plant installation.
  • Identify any additional work required as part of the next stage Feasibility study.

The study was completed in April 2017 and provided AGA with:

  • A comprehensive review of all aspects of Grade Engineering® related to Gramalote.
  • Preliminary assessment of Surge Slave Separator (working title) vs Fixed Grade Engineering® plant trade off study.
  • A forward plan of work required in the feasibility study.



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