Bardoc Gold Project
Following Bardoc Gold’s merger with Excelsior Gold Limited (ASX:EXG), Bardoc acquired the 100%-owned Bardoc Gold Project located 30 to 55km north of Kalgoorlie in Western Australia.
The Project covers 96 square kilometres of granted mining leases and prospecting licences over the intersection of the well mineralised Bardoc Tectonic Zone greenstone sequence with the cross cutting Black Flag Fault system. The convergence of these major gold mineralising structural systems has resulted in widespread gold mineralisation throughout the Project area.
Historic gold production of 56,700 ounces is recorded from the Bardoc Mining Centre located in the central part of the Project. This production occurred largely from the underground Zoroastrian mine in the late 1890s to early 1900s. Recent production from the Zoroastrian and Excelsior open pits by Aberfoyle Gold from 1987 to 1991 totalled 2,220,000 tonnes at 1.6g/t Au for 113,000 ounces of gold.
The Excelsior deposit is hosted within a sequence of tightly folded and sheared ultramafic/sedimentary schists within the Excelsior shear zone. Gold mineralisation occurs in a broad 20 to 50 metres wide zone of altered quartz-sericite-carbonate schists.
The Excelsior shear is a major north-northwest trending structure up to 80 metres wide and extending for over 6 kilometres to the north and potentially 15 kilometres to the south of the Excelsior deposit within the Project tenements. Satellite resources at Lochinvar, Three Star and Ellen Pearce to the north and at Castlereagh, Parkerville and Snibbo to the south demonstrate the potential for additional gold resources along the shear.
The deposit was re-interpreted and re-estimated using the LUC method by EGX during 2018.
Table 3: Excelsior Resource LUC Model >=0.50 g/t Au above 200mbs – OP resource
Isometric view of Excelsior deposit (looking down towards the NE) of wireframe interpretation of main lode systems
During 2016/17 open pit mining by Excelsior Gold concentrated on the Zoroastrian system where gold mineralisation is hosted in quartz veins and stockwork zones within the differentiated Zoroastrian Dolerite. The quartz veining has been defined over a strike length of 1.4 kilometres and remains open below a vertical depth of 380 metres . The high gold grades associated with the stockwork and narrower vein style mineralisation demonstrates excellent potential for the delineation of further open pit and underground resources.
Mining of the Zoroastrian open pit by the Company to a depth of about 110 metres below surface produced approximately 55,000 ounces from 810,000 tonnes of ore grading 2g/t Au treated at the Paddington plant and Golden Mile Milling’s Lakewood plant.
Subsequent to the completion of mining at Zoroastrian (Central Pit) EXG drilled 42 RC and DC holes for 7,760m which have been included in the new consolidated Mineral Resource Estimation.
Table 4: Zoroastrian Resource LUC >=0.50 g/t Au above 200mbs – OP resource
Table 5: Zoroastrian Resource OK Model >=2.50 g/t Au below 200mbs – UG resource
Isometric view of Zoroastrian deposit (looking down towards the NE) of wireframe interpretation of main lode systems
The new interpretation of the distribution of mineralisation within the Zoroastrian Dolerite and the adjacent sediment contact provides a template for the assessment of other prospects along the 13 kilometres of strike of the dolerite unit within the Project tenements to the south of the open pit and in other parallel dolerite horizons.
The Bulletin South area in the southwestern portion of the Project tenements hosts gold mineralisation more closely related to the Black Flag Fault system rather than the Bardoc Tectonic Zone shear structures.
Gold mineralisation at Bulletin South is associated with stockwork zones within a felsic porphyry unit proximal to the regionally significant Black Flag Fault structure, which is interpreted to be close to the southern end of the former open pit. Primary gold mineralisation in the quartz stockwork system within the felsic porphyry may represent mineralisation along splay structures emanating from the Black Flag Fault. The stockwork mineralisation in the porphyry averages 15 metres true width.
The mineral resource estimation for Bulletin South was completed by Cube Consulting PTY LTD using the LUC estimation method.
Table 6: Bulletin South Resource >=0.50 g/t Au above 200mbs – OP resource