The Kvemo Bolnisi (“KB”) area includes a number of discrete mineralised targets, including the most advanced project Kvemo Bolnisi East (“KBE”). Other targets include the GZ3 polymetallic-gold discovery immediately west of the Gold Zone 2 area; Kvemo Bolnisi West, a polymetallic-gold-silver target with historical drilling and adits; and Kvemo Bolnisi South, an area of historical workings and soil anomalies south of Copper Zone 1. The potential exists for a local mineralised field in the KB area centred on a series of breccia pipes and other controlling structures, as is the case at Madneuli, a 30-year old mining operation only a few kilometres away.
Location and Infrastructure
The KBE Copper Gold Project sits less than 7 km to the north-east of the producing Madneuli mine and processing plant operated by the Rich Metals Group (“RMG”), the production company operated by Empire Metals’ local partner. This mine has produced approximately 85 Mt of copper and gold bearing ores, at a reported grade of 1.0g/t Au and 1.0% Cu, over a period of 30 years.
Empire Metals has signed a Memorandum of Understanding (“MoU”) with RMG to reduce the capital investments required for production and offers the Company an alternative to a standalone operation. Furthermore, the MoU outlines mining and processing arrangements for the future production of precious and base metal ores mined from the KBE Project.
There is a good pool of local mining experience, including technical staff thanks to the Madneuli operating in the region for the past 30 years. Furthermore, regional infrastructure is in good order and services a network of population centres and villages, including the regional centre at Bolnisi. As a result, infrastructure requirements at the advanced KBE project are very straightforward, requiring only site access roads, a small number of dumps and stockpiles, some water management facilities, and a road to connect with the Madneuli operations.
Gold-copper mineralization at KBE’s Copper Zone and Gold Zone 2 is intimately linked to the emplacement of polymict breccia pipes and envisaged to be syngenetic or closely post-emplacement. This has resulted in the formation of a silica-sulphide (pyrite-rich with common chalcopyrite) and gold matrix within the central facies of the breccia pipes and steep angle silica – sulphide veining within the ignimbrite host.
The subsequent weathering of the sulphides has produced silica-iron oxide veining within the ignimbrite body, substantially elevating gold grades to a peak sample of 82.1 g/t Au. Hypogene veins are also observed typically bearing quartz-pyrite +/- chalcopyrite.
During weathering the copper in chalcopyrite was remobilized downwards to form a high-grade chalcocite enrichment zone.
The recent GZ3 mineralized zone immediately to the west of Gold Zone 2 has demonstrated further evidence for the larger system at KBE and consists of deeper, polymetallic gold mineralisation associated with breccia bodies.
Copper-Gold Sulphide Ore – Flotation Testing
- Scoping level metallurgical testing was successfully completed on four composite samples made up of 18 core samples totalling 85.7kg derived from 18 separate diamond drill holes representing a cross section of the ore types found at KBE and across Gold Zones 1 and 2 and the Copper Zone.
- Preliminary results indicate copper and gold found in the primary KBE mineralisation is recoverable using standard froth flotation processing. Peak recoveries of >90% for copper and 82% for gold were achieved, but the variety of copper species present requires a more comprehensive testwork programme which will commence in the next phase of study.
Gold Oxide Ores
- Results of bottle roll and column leach testwork, which was carried out on 68 half-core samples with a combined weight of 207.3kg, indicate gold oxide resources at KBE are amenable to heap leach gold extraction.
- Bottle roll tests included eight composites crushed to -20mm and -12.5mm. The average gold recovery for the -20mm crush size composites was 74% and the average for the -12.5mm composites was 79%.
All bottle roll testwork indicates that the gold oxide Resource defined at KB is suitable for heap leach gold extraction.
As part of column leach testwork, 60kg of the original test composite was subject to agglomeration and percolation testing, along with column leaching at two crush sizes. The column leach gold recoveries using the leach liquor and residues assays were 87.5% and 88.4% for the -20mm crush size and the -12.5mm crush size respectively.
Development and Optimisation
A detailed project development plan has been prepared for the KBE project, passing from infill drilling and further testwork through to Feasibility Study and construction.
The KBE mineralized system has been reviewed in detail and work is now extending to introduce geo-metallurgical factors into resource models.
Using in-house engineering expertise, the Company has accelerated production planning and scheduling scenarios designed to:
- Increase understanding of the anticipated project footprint as a base for mineral inventories used for initial pit optimizations, including production scheduling and sensitivity studies.
- Develop concepts for the future operation in terms of on- and off-site infrastructure required, most notably the haul road from KBE to the Madneuli plant. This improves estimations of costs and ensures the ESIA covers all aspects of the operation in line with international best practice.
- Understand the potential scale of the project as a combined gold oxide/copper sulphide open pit, including future-proofing for potential upside from resource expansions following the planned infill and KB exploration drilling.
- Optimize the design of infill and infrastructure sterilization drilling for a range of possible open pit scenarios based on input sensitivities.
Developing concepts for pit designs and surface infrastructure in parallel with infill drilling programmes and in advance of the Feasibility Study will ensure the latter is well designed and future-proofed for the expected size of operation. It also allows other investigatory work to be carried out early in the project development schedule.