Woodlawn Regional Exploration
Updated February 2017
Heron continues to maintain and explore a strategic, 620 km² tenement package over the prospective Silurian volcanic rocks around the Woodlawn Mine. The exploration strategy is to focus on known mineralisation with comparable metallurgy to Woodlawn and within proximal trucking distance of the proposed Woodlawn concentrator. Targeted satellite production feed grades and other economic parameters will look to displace tailings reprocessing as the plant feed. A number of excellent targets exist.
The Currawang Prospect, wholly owned by Heron, is located 10 km northwest of the Woodlawn mine and produced approximately 0.5Mt of high-grade polymetallic ore from an underground operation in the early 1990s that was processed at Woodlawn. The attraction of the Currawang mine is it has the potential to open up a second, nearby production centre at Woodlawn which could provide an additional high grade production source and displace the lower grade tailings re-processing.
The Company is undertaking a comprehensive review of the project covering:
- Data validation
- Geophysical analysis (magnetics and down-hole electromagnetics (DHEM))
- Digitising and wireframing of the 1990s underground geology plans to generate a 3D geology and fault model
- Review of mineralised intercepts outside the mined stopes
A number of significant historical intercepts that occur outside the mining stopes have been identified, including:
- 10.1m @ 17% ZnEq (9.0% Zn, 0.89% Cu, 4.3% Pb, 54g/t Ag), CU054:
- 8.6m @ 16% ZnEq (8.8% Zn, 0.76% Cu, 5.2% Pb, 34g/t Ag), CU056:
These drill holes are in the northern part of the old mined areas and at the time of their drilling did not warrant following up. Further assessment is on-going and a follow-up drill hole program has been designed to test the down plunge extension of these intercepts. Combined with high-powered DHEM survey, this program has the potential to identify new extensions to the Currawang mineralisation. An initial program of 3 diamond drill holes for 2,120m has received a NSW New Frontiers Cooperative Drilling grant which provides for reimbursement of 50% of the drilling costs, drilling is expected to commence later in 2017.
6 km WNW of Woodlawn, where broad zones of intense pyrite-sericite alteration in Woodlawn Volcanics are present. Limited drilling in the 1980s and 1990s intercepted zones of modest-grade mineralisation which received little follow-up work. Remodelling of the numerous historic fixed- and moving-loop EM geophysical anomalies has provided clear targets for follow-up testing.
Other Woodlawn Prospects
The Allianoyonyiga and Kalua Prospects are both grassroots prospects defined by pre-Heron moving loop EM surveys, situated along strike, west and east respectively from the Cowley Hills deposit. Moderate silica/pyrite alteration in rhyolitic volcanic rocks has been mapped at Kalua along strike from the EM anomalies, whereas the Allianoyonyiga Prospect is wholly covered by alluvium of the Allianoyonyiga Creek and will require drilling to test further. At Hickory’s Paddock a recent soil program has defined a 300m long Zn/Cu/Pb anomaly associated with a gossanous black shale horizon.
East Lachlan Regional Projects
The Company retains a significant portfolio of tenements in the East Lachlan area of New South Wales within hauling distance of Woodlawn, the key project areas being Cullarin and Kangiara.
Cullarin Project (EL7954, EL7468, 100% Heron)
The Cullarin Project is located 20 km NW of Woodlawn and 30 km west of Goulburn and covers the prospective Silurian-aged Wet Lagoon Volcanics – a sequence of rhyolite and dacitic volcanic and volcaniclastic rocks with potential for VMS, skarn and shear-related gold and base-metal deposits.
The project had been a joint venture with Golden Cross Resources Ltd (ASX: GCR), however Heron recently bought GCR’s interest thereby terminating the agreement between the parties and Heron now owns the project 100% with no further encumbrances.
Previously reported exploration in the south of the area has highlighted the prospectivity of the Wet Lagoon Prospect where several encouraging gold intercepts were drilled by North Ltd and others in the1980s (nominal 0.5g/t cut-off grade applied):
- 32.0m @ 1.5g/t Au from 83.0m, WL017
- 24.4m @ 3.3g/t Au from 16.2m, WL031
- 20.0m @ 2.3g/t Au from 70.5m, WL024
- 65.0m @ 1.6g/t Au from 31.0m, WL028
- 18.9m @ 0.64g/t Au from 64m, WL029
These results have been sourced from historical open-file reports and have not been verified by the Company, except where original drill logs and assay sheets have been used to validate within a dedicated database. Many of these better drill results occur close to the carriageway of the major Hume Highway and future work will need to be directed away from infrastructure areas.
The Wet Lagoon Prospect will be re-evaluated for its potential to host a major gold deposit as it is clear a very significant mineralising event has taken place over a broad, 5 km long area.
Kangiara Project (EL8400, 100% Heron)
The Kangiara Project is located 90 km NW of Woodlawn and 26 km NNW of the town of Yass. It covers felsic volcanic and related sedimentary rocks of the Silurian Douro Group. Kangiara itself is a historical copper mine and previous explorers (to 2014) have delineated a small, low-grade gold, silver, copper, lead zinc deposit, which is not JORC 2012 compliant. Potential exists to build on this position.
At the Crosby Prospect (named after the nearby trig station) 5 km to the NE of Kangiara, previous explorers (in particular Oakland Resources Ltd around 2011) outlined a strong gold anomaly (2.3g/t Au in rock chips and 0.17g/t Au in soils) within a 2.5 km NW-trending zone of anomalous geochemistry (Au, As, Zn, Pb, Cu). These results are from public open-file sources and the Company has not been able to verify these results, however earlier (1970s) soils results showed Pb and Cu anomalism in the same area (not assayed for Au at the time) providing some confirmation for the more recent results.
The anomaly has reported zones of pyrite at surface and lies within rhyolitic to dacitic volcanics and volcanoclastic units of the Hawkins Volcanics. The setting is similar to the McPhillamys gold deposit (approximately 2.2Moz Au as reported by Regis Resources Ltd) located 130 km to the NNE.
The Crosby Prospect provides the opportunity for a greenfields gold/base-metals discovery. Oakland Resources Ltd were proposing to drill the prospect before their very limited funding was redirected. Access is relatively straightforward being on privately owned sheep grazing paddocks approximately 2 km from the nearest homestead. The Company is planning to conduct a program of verification sampling and mapping prior to designing a drill program to test for mineralisation at depth.