Bardoc Tectonic Zone Gold Project ARL 100%
The Bardoc Tectonic Zone (BTZ) is a major, gold-fertile, crustal-scale structure that transects the Kalgoorlie Terrane of the Eastern Goldfields. The regional shear/fault system strikes from Paddington in the south to northwest of Ghost Rocks in the north and extends over an approximate 125km strike length, of which some 65km occurs within Ardea tenure. Ardea’s GNCP is unique among the world’s lateritic nickel-cobalt deposits in that it has developed on ultramafic rocks that are within and are a part of a major, crustal-scale gold-mineralised structure being the BTZ.
The BTZ typically dips moderately to the west, hosting the Paddington, Goongarrie, Comet Vale, Yunndaga, Menzies, Lady Irene and Lady Isobel historic gold mining centres. To the south, the BTZ is contiguous with the Boulder-Lefroy Fault, the host to the Kalgoorlie Golden Mile, New Celebration and St Ives gold mining centres and is considered to be part of a single gold-fertile crustal structural system stretching from St Ives in the south to Ghost Rocks in the north.
Big Four gold prospect
The Big Four gold prospect is located within the BTZ south of Goongarrie and offers an exceptional gold exploration opportunity for Ardea with high gold grades apparent in shallow geological settings. Limited historic mining around the 1920s to 1930s recovered 571.5t of ore for 10.53kg Au (~339oz Au), at an average grade of 18.4g/t Au. This gold occurrence cropped out at surface so was discovered by prospectors. Most of Ardea’s tenure is covered by shallow alluvial cover and/or the development of a laterite profile which obscures the underlying gold potential.
The most recent Ardea drill results from the Big Four area, as well as reassessed historic data, shows that strong, laterally extensive gold anomalism is present beneath the full 20km strike length of the nickel-cobalt orebodies of the GNCP. The exceptional thickness and grade of the GNCP laterite is interpreted to be directly attributable to deep and intense weathering along BTZ bedrock shear structures, particularly at the eastern contact of the Walter Williams Formation (WWF) laterite host rock with the stratigraphically overlying Siberia Komatiite.
During the December 2019 Quarter, Ardea geologists sourced all available historic drill hole data and compiled it into an electronic drill hole database to allow first-pass models of the controls on gold mineralisation to be defined. This knowledge is being applied to the rest of the BTZ controlled by Ardea to help generate additional targets for drill exploration.
At Big Four, follow up drilling is planned to be completed during Q1, 2020. The initial focus will be infill and confirmatory drilling around the historic mine area targeting the dominant gold host rock, porphyry intrusive and surrounding altered ultramafics.
Ghost Rocks gold prospect
Three main prospect areas have been defined at Ghost Rocks, being the Lady Isobel gold prospect, the Twelve Mile base metal prospect and Ghost Rocks Southeast gold and nickel prospect. Soil auger drilling, rock chip and geological mapping data have been used to generate drill targets around historic gold workings at Lady Isobel. A first phase drilling program targeting quartz veins subject to historic mining is planned to be completed in Q1, 2020.
Windanya gold prospect
Windanya is a historical gold mining centre that was operational in the 1900s. It is hosted within the BTZ, 20km south of the GNCP Scotia Dam nickel-cobalt deposit. Historic gold workings are evident on the tenement and extend as a corridor to other workings to the north and south of the Ardea tenement. The trend of the mineralised zone appears to be approximately 330˚.
Gold mineralisation appears to be focused on a marker unit designated by the Geological Survey of WA as the Big Dick Basalt and the overlying Mt Pleasant Gabbro. The location of the mineralisation, in the hangingwall of the Siberia Komatiite, is analogous to the New Boddington gold mining centre at Goongarrie, and to parts of the Ardea Zeus prospect at Big Four, which both trend around 330˚. Like these prospects, the mineralisation may well be stretched along sheared stratigraphic contacts, but also localised on minor cross-cutting structures.
Compilation and interpretation of historic data continues with records sourced for the Half Mile Reef located near the centre of Ardea’s Windanya tenure, indicating that between 1897 and 1906, 23,480 tonnes of ore were mined from an underground operation, producing 12,993 ounces of gold. This indicates a recovered gold grade of 17.2 g/t.