Results from the re-assaying of intercepts delivered from Legacy Minerals’ (ASX: LGM) stage one reverse circulation drilling program at the Harden gold project in New South Wales has identified grades of up to 19.35 grams per tonne.
Drilling initially recorded a range of assays including 2 metres at 19.09g/t gold and 3m at 5.12g/t gold however Legacy decided to re-split and re-assay bulk samples within the mineralised zone due to very high grades, the observation of visible gold in quartz, and field duplicates indicating a potential nugget effect within sampling.
Re-assaying confirmed confidence in the sampling technique and the high-grade results as well as a variability in assays caused by an interpreted coarse gold nugget effect even at lower grades (less than 0.2g/t gold).
Legacy also completed screen fire assaying over intervals which had been observed to contain visible gold and higher gold grades.
The results suggested the presence of a nuggety gold effect in the samples however the company said for the most part, field and laboratory duplicate screen fire assays showed “good repeatability and did not point to a significant sampling issue”.
Legacy has also completed two diamond drill holes for 538.5m at Harden, of a planned five-hole program totalling 1,200m.
The holes are testing along strike and down dip of historic workings which previously produced 55,000oz at 21.5g/t gold.
The first hole was completed to a depth of 286.9m and designed to test down dip of the western end of the workings.
Mud rotary drilling was completed to 159m before diamond drilling through to end-of-hole.
The hole intersected a 22m-wide zone of sheared, moderate-to-strong quartz-sericite-pyrite-altered granodiorite while a significant fault zone resulted in 2m of core loss in the target area.
Coarse arsenopyrite was sporadically distributed within the more intensely sheared zone.
Second diamond hole
Legacy completed the second hole to a depth of 251.6m to test the interpreted down plunge potential of the Harden gold mine.
The hole intersected a weak quartz-sericite altered shear zone and associated quartz veining between 194m to 197m before the main target area was intersected between 212m to 229m.
The area is characterised by a variably sheared and quartz-sericite-pyrite altered granodiorite with associated quartz veining and silicification.
Nature of mineralisation
Legacy managing director Christopher Byrne said the independent re-split and re-assaying process and screen fire analysis were important steps in understanding the nature of Harden’s high-grade gold mineralisation.
“The information confirms our confidence in the high-grade gold results [and] will be used to guide sampling and analysis moving forward,” he said.
“Diamond drilling is also providing valuable structural information which is key to understanding the geometry and controls on mineralisation that will also guide future drill targeting.”
Historic gold mines
The Harden project comprises several historic high-grade gold mines in the Lachlan Fold Belt district which has produced more than 460,000oz gold from alluvial and hard rock mining.
The mines within Legacy’s tenement package were among the largest hard rock operations in the district, producing a combined total of 75,000oz gold at an average grade of 28.6g/t before 1919.