Gold Terra is currently completing a compilation of all available historical drill data from the Con mine and recent Gold Terra surface sampling, airborne geophysics, LiDAR and soil and lake geochemistry to develop specific drill targets along the Campbell Shear zone. In parallel, an ongoing structural analysis is being carried out from the Campbell Shear mine area to better understand the controls on the high-grade gold lodes, which will assist in the Company’s targeting of the Campbell Shear both to the north and south of the Con mine.
The Campbell Shear zone is within secondary and tertiary structures associated with a large district-scale structure, the Yellowknife River Fault Zone (“YRFZ”), that straddles the Company’s property over 67 km of strike length on the southern and northern extensions. The Campbell and Giant Shear zones are prolific regional structures in the Yellowknife mining camp, responsible for the majority of the 14 million ounces of gold mined at the Con and Giant mines up to their closure in the early 2000s. In reference, the YRFZ is equivalent to the better-known prolific gold camps in Abitibi, like the Destor-Porcupine and the Larder Lake-Cadillac Fault zones.
Gold production in Yellowknife over a period of 60 years was along 8 kilometres of the YRFZ trend, or approximately 10% of the known fault structure, which includes the high-grade gold mineralization on the Campbell Shear. The Campbell Shear zone and associated structures such as the Con Shear are exceptional due to the high-grade nature of the lode deposits (approximately 16 g/t Au).
The Campbell Shear remains largely unexplored north and south of the historical mines, on ground now controlled by Gold Terra. Of particular importance, from a series of holes from the 1960s drilled on the Company’s Southbelt property, 2 kilometres south from the southern end of the Con mine workings, one hole (KA-06) intersected mineralization in the Campbell Shear at a shallow depth with 8.23 g/t over 7.8 metres1 (Figure 1).
On the Northbelt, the Company’s first two holes completed this winter successfully intersected the favorable stratigraphic sequence associated with the Campbell Shear zone at the Con mine (Figure 1). Both holes, drilled 1 kilometre apart, intersected multiple shear zones containing quartz veining and sulphides with one of the holes having visible gold(Figure 2). Although gold values were anomalous (<0.22 g/t), the alteration and shearing indicate similarities to the Campbell Shear structure and potential proximity to high-grade gold mineralization.
The Campbell Shear at the Con Mine
At the Con mine, the Con and Campbell Shear zones are separated by approximately 2 kilometres of stratigraphy, with the Campbell Shear crossing different geological units and varying from occurring adjacent to and up to 1 kilometre west of the Jackson Lake Formation (Timiskaming equivalent) and east of a breccia unit called the Bode Debris Flow. Within these bracketing units are extensive areas of deformation up to and including sericite-carbonate shears that were the host to the Campbell Shear ores.
Analysis of the Campbell Shear at the Con mine showed that although the shear has extensive strike (+10 kilometres), width (up to 175 metres) and depth (mine workings to approximately 2,000 metres), only a very small percentage of the shear (approximately 1%) was mined as high-grade lode gold deposits (Figure 3).
Campbell Shear Target on Northbelt
Work to date on the property indicated that the stratigraphy hosting the Campbell Shear of the Con mine (responsible for approximately 5 of the 6 million ounces produced) possibly extends onto the Northbelt ground held by Gold Terra.
During the winter of 2020, the Company drilled two holes at a 1 kilometre spacing for a total of 1,274 metres targeting the Campbell Shear stratigraphy. Both holes successfully intersected the Campbell stratigraphy package including the Jackson Lake Formation in the hanging wall and the Bode Debris Flow in the footwall. The two holes intersected broad zones (up to 200 metres) of Campbell Shear deformation style and shearing, including chlorite-carbonate-sericite alteration in multiple shears that were accompanied by quartz-carbonate veining. Visible gold was noted in one hole (Figure 2) but gold values did not exceed 0.22 g/t. The vein systems also had significant multi-percent sulphide mineralization which included anomalous arsenic and antimony. Haloes around these mineralized zones for up to tens of metres were elevated in potassium and depleted in sodium. All of the features intersected in the two holes are recognizable characteristics from the Con mine with the appearance of the Campbell shear proximal to the historically mined ore zones.
Photos below show that the shearing, alteration and mineralization intersected in Gold Terra’s holes are very similar to the Con mine ore (Figure 4)(Figure 5)(Figure 6).
Campbell Shear Target on Southbelt
On Gold Terra’s Southbelt property, the extension of the Con and Campbell Shears covers approximately 8 kilometres of strike south of the Con mine. The extension of the Campbell Shear has been established by the mapping of the recognizable Campbell Shear stratigraphic package and historical drilling.
Historical exploration programs along the Campbell Shear on Gold Terra’s Southbelt property included a small exploration drilling program of approximately 6 holes (KA series) over a 250-metre strike length. All holes intersected multigram gold values, with the best hole (KA-06) reportedly intersecting 8.23 g/t over 7.8 metres1 at a depth of approximately 110 metres below surface. Additionally, surface sampling by Gold Terra of exposed sheared zones to the west of the Campbell Shear (hanging wall) included quartz veins with up to 94.9 g/t Au (NR September 23, 2015).
Other limited historical drilling carried out on Gold Terra’s Southbelt property did not test the Campbell Shear target. Gold Terra has 8 kilometres of a known high-grade gold bearing structure that is relatively unexplored with high potential to host Campbell shear-style mineralization.
Note: 1 The intersection stated here is historical in nature and has not been verified by Gold Terra. Hole location, downhole survey, assay and lithologic data was obtained from the Con mine databases, and therefore is assumed by Gold Terra to be reasonably valid.
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