Medallion Metals Ltd (ASX:MM8) has taken another key step in moving the flagship Ravensthorpe Gold Project (RGP) towards production with a metallurgical review underway to confirm historical high recoveries of gold and copper.
GR Engineering Services Limited (GRES) has been engaged to undertake a comprehensive review of all historical metallurgical test-work undertaken on RGP ores.
This work is expected to confirm a conventional process route for Ravensthorpe ore and to advise on further work required to support a future definitive feasibility study
“An important step”
Managing director Paul Bennett said: “The metallurgy review is an important step for Medallion to both consolidate the significant amount of historical work done and plan for the future.
"Our intention is that the next round of metallurgical test-work is definitive and final such that it supports a definitive level of assessment of RGP.”
The cumulative results of all historical test-work conducted provides a large database upon which to conduct the GRES metallurgical review.
Previous test-work
Three substantial phases of metallurgical test-work have been undertaken on RGP ores, the first in 2005, followed by more recent programs in 2018 & 2019.
The 2005 and 2018 programs comprised analyses of sample mineralogy, comminution, gravity separation, whole ore cyanidation, flotation testing, cyanidation of flotation tails in addition to investigations into the properties of concentrates and tailings produced through the test-work.
The 2019 program was limited to whole ore cyanidation and tailings detoxification tests.
High recoveries
Test-work to date has confirmed high recoveries of gold and copper from conventional process routes.
Gold recovery averages 95.9% and 92.5% for all historical gravity-flotation-leach and gravity-leach tests respectively while copper recovery averages 73.0% for all historical flotation tests.
"The historical results suggest high gold and copper recoveries can be consistently achieved using industry-standard processes,” Bennett said.
Review by GRES
GRES’ review will be tasked to confirm that an industry-standard gravity/flotation/leaching process route is the preferred option to maximise gold and copper recovery from RGP high copper ores, with estimates of reagent consumptions, recoveries and concentrate grades expected under normal operating conditions.
It will also investigate the ability to bypass the flotation step for low copper ore.
Additionally, a gap analysis will be undertaken to establish what additional metallurgical test-work is required to support a definitive feasibility study (DFS) level of assessment of the technical and commercial viability of RGP in the future.
To confirm viability
Consolidating the large amount of historical test-work forms a key milestone for confirming the technical and commercial viability of RGP.
"This work will increase certainty that those results are repeatable across the lithologies and deposits and can be scaled up to commercial rates,” Bennett said.
"We’re pleased to have an industry leader in GR Engineering assist us in this regard.”
GRES’ long involvement with the design, construction and recent enhancement of the Deflector gold-copper process plant ensures it is well placed to advise Medallion on process design and engineering given RGP is expected to share many of the same aspects of Deflector in terms of scale and configuration given the mineralogical similarities.
The company expects to report the findings of the GRES metallurgical review in December 2021.