Xanadu Mines Ltd (ASX: XAM, TSX: XAM) has announced a highly encouraging update from the new metallurgical test programme at its flagship Kharmagtai project in Mongolia.
The company reported that Metallurgical test work yielded high grade copper and gold concentrate at Kharmagtai, indicating a major value uplift for Kharmagtai.
Xanadu reported an estimated 4.5% increase in copper recovery to achieve an average recovery of 89.5% for the two main metallurgical composites; and an estimated 3% increase in gold recovery to achieve an average recovery of 69.7% for the two main metallurgical composites.
The concentrate grades averaged 25.2% Cu and 25.8g/t Au for the two locked cycle tests.
Xanadu expressed confidence that further optimisation work may lead to further improvements.
The Kharmagtai Project is an advanced copper-gold exploration project located in the Omnogovi Province of southern Mongolia and secured under a mining licence.
The Kharmagtai Project consists of a number of separate sulphide deposits, Stockwork Hill, White Hill, and Copper Hill; and two new deposits, Golden Eagle, and Zaraa.
The company’s 2018 Mineral Resource Estimate and 2019 Scoping Study had achieved high copper and gold recovery and high concentrate copper and gold grades.
New metallurgical test programme
Xanadu reported that it has conducted a new metallurgical test programme on sulphide ore at Kharmagtai project.
The company said that the program was conducted at SGS Canada in Vancouver, BC under the direction of David Middleditch and Andy Holloway of AGP Mining Consultants Inc.
The 2019 metallurgical test program was designed to improve upon metallurgical assumptions in the 2018 Mineral Resource Estimate and 2019 Scoping Study.
XAM reported that new composites, three domain, and nine variability were selected by Xanadu geologists with input from AGP personnel to represent the main geological and alteration domains within the open pit portion of the three existing deposits and to be representative of material in the 2018 Mineral Resource Estimate.
Flotation test work on these composites consisted of a series of batch rougher and cleaner tests with locked cycle tests conducted on the two main Master Composites.
Head grade and sample selection the key differentiators
The company noted that the key differences between the 2008 test work and the 2019 test work relate to head grade and sample selection.
The 2008 tests were conducted on samples with copper and gold grades not representative of the bulk of the open pit mineralisation. Samples selected for the 2008 test work were not selected based on metallurgical or geological domains.
In contrast, samples within the 2019 test program were selected based on a geometallurgical model developed by CSA Global, which represents different rock and alteration types throughout the three deposits.
3% increase in gold, 4.5% increase in copper recoveries
The company announced that Copper and gold recoveries averaged 89.5% and 69.7% respectively for the two main master composites, ranging from 89.3% to 89.7% for copper and 60.8% to 78.7% for gold.
This is an estimated 4.5% increase in copper recovery and 3% increase in gold recovery.
XAM reported that Copper concentrates graded at an average of 25.2% Cu and 26.5g/t Au and ranged from 24.8 to 25.6% Cu and 21.5 to 30.0g/t Au.
Xanadu expressed confidence that further optimisation work in the future may lead to further improvements.
The company reported that the mineralisation is open at depth and along strike.
Xanadu said that the current estimates are restricted to those expected to be reasonable for open pit mining.
XAM noted that the limited drilling below this depth (- 300m rl) shows widths and grades potentially suitable for underground extraction.
Xanadu said that the exploration is on-going.
Xanadu’s Managing Director & Chief Executive Officer, Dr Andrew Stewart, said “We are extremely pleased with these new metallurgical results from Kharmagtai, which are in line with or better than expected at this stage in the projects life and we are comfortable that additional improvements can be made further down the track.
These early stage flotation test results are very encouraging and indicate that a standard crushing, grinding and flotation process will be enough to deliver good extraction of the economic minerals from the deposit.
In combination with the low content of deleterious elements, we foresee no significant hurdles to producing a high-quality concentrate via standard processing pathways that will be in high demand from all the major global copper smelters, at a time the time of production.”