Thanks eastwest101 and precis. Have dug back into old ASX announcements and below shows the path from 2017 to shelving the Nymagee PFS in 2019. The plan back then was to add Nymagee to Hera and extend the mine life about 4 years.
It seems at that time the contaminants (talc, phyrrotite) were too big a hurdle - as well as a less than economic ore to work with.
For me uncertainty exists as to why those problems (insurmountable then) are not more fully addressed in today's Nymagee announcement?
E.g. is it a different mineral interpretation, better technology or simply different/deeper ore bodies we are drilling into compared to back then?
23 February 2017
A Nymagee scoping study was approved by the Board. For a potential underground higher grade copper and lead zinc development opportunity.
2 May 2017
“Aurelia Metals Limited (“AMI” or the “Company”) is pleased to announce the results of the Nymagee Scoping Study (“Study”) were positive and justify the Company committing to the next stage of development being a Pre-Feasibility Study (PFS).
Critical areas for further work include:
·Mine dewatering plan (method, timing and cost)
·Detailed review of geological model and update
·Geotechnical review of underground mining conditions
·Metallurgical, comminution & flotation testwork.
·Processing strategy and configuration based on testwork
·Environmental monitoring plan and approval pathway
·Firm legal understanding on Joint Venture operation
7. PROCESSING
Ore is assumed to be processed through the Hera plant which is assumed to contain a copper flotation circuit and sufficient filtration capacity as part of the Hera plant upgrades. Plant throughput is forecast at 380-400,000 t/y. Ore hardness data suggests the ore is suitable with the Hera comminution circuit. Testwork on Nymagee ore was predominantly conducted by Metcon Laboratories (division of Ammtec) during 2010 to 2012.
The Study assumes a Cu conc grade of 25% with 90% Cu recovery and 80% Ag recovery (as supported by the testwork). The Bulk Pb/Zn grade assumed to be 55% with 90% Pb/Zn recovery, 80% Ag recovery (in line with Hera experience).
Further metallurgical and flotation testwork is required to optimize recovery and rejection of impurity elements (particular arsenic).
Ore grades processed in the early life of the project consist of predominantly high grade Pb+Zn and low Cu, with a transition to High Cu and low Pb+Zn over the life of mine. Payable metal production averages approximately 6,000-8,000 t/y copper, 3,000-5,000 t/y lead, 6,000-8,000 t/y zinc over the commercial phase of the operation.
5 June 2019
NYMAGEE PFS
Pre-Feasibility Study (“PFS”) activities on Nymagee have focused primarily on metallurgical testwork.
Recent testwork results have indicated that as a result of the presence of contaminants in the Nymagee ore, particularly talc and pyrrhotite, the assumed Scoping Study base metal recoveries are unlikely to be achievable.
The extent of these contaminants was not evident in the early metallurgical testwork utilized to support the Scoping Study.
In addition, the work index of ore tested was higher than assumed in the Scoping Study, resulting in higher power consumption and lower throughput rates, which both lead to higher operating and capital cost than were anticipated. The impact of these results on modelled cut-off values on the 2018 block model has resulted in a significant reduction in preliminary estimates of economically recoverable resource tonnes.
Accordingly, AMI has decided to defer further Nymagee PFS work at this stage. It intends to consider possible project rescoping on the basis of the reduction in economically recoverable resource tonnes, and the potential impact of any future exploration success. Should future exploration increase the Nymagee resource base significantly, the decision to defer further PFS work would be revisited.
But yes good news about Federation progress again, post the rainfall event.
(20min delay)