Consolidating one of Australia's great mining jurisdictions
PINNACLES MINE OVERVIEW & HISTORY
The Pinnacles Mine, located 15km south-west of the Broken Hill township, is considered to contain one of the highest grade and shallowest known deposits in Broken Hill. The Pinnacles Deposit remains relatively undeveloped, with only small-scale historical mining targeting the rich Galena (lead ore) lodes occurring since it was originally opened in the 1880s as an underground lead-silver mine.
For over 70 years the Williams family have owned the Pinnacles Mine, following its initial acquisition by Edward Williams in 1952. The Pinnacles Mine has been progressively developed and operated by the Williams family since this time under the leadership of Edward, his son Teddy and eventually his grandson Craig, with the later remaining the current Chairman of Pinnacle Mines Pty Ltd.
Over 55,000m of drilling has been completed at the Pinnacles Mine to date, with approximately 33,000m occurring since 2001. In addition, approximately 22,000m of trenching has been completed at the Mine. Operations from the Edwards Pit at the Pinnacles Mine began in early 2007, producing lead oxide ore which was transported from the Mine’s rail siding to Port Pirie for smelting. The Mine was then progressively expanded to include on site production of zinc and lead concentrate.
Operations were placed on care and maintenance in 2020 due to Covid, however drilling has continued on site, expanding the known resource base. The Edwards Pit borders five other potentially significant deposits which make up the overall Mineral Resource for the Pinnacles Mine, including the most recent discovery of the high-grade Perseverance Deposit.
Pinnacles Exploration Target
An Exploration Target has been estimated for the Pinnacles Mine area of between approximately 6Mt to 15Mt at approximately 2-4% Zn, 3-6% Pb and 40–125ppm Ag. The Exploration Target comprises potential mineralisation below and adjacent to the current Pinnacles MRE.
The potential quantity and grade of the Exploration Target is conceptual in nature and there has been insufficient exploration to estimate a Mineral Resource, and it is uncertain if further exploration will result in the estimation of a Mineral Resource.
The Exploration Target is derived from historical drilling which enabled extrapolation of the mineralised domains (Main Lead Lode and Immediate Footwall Zinc Lode only) beyond the limits of the Inferred Resource. This extrapolation is based on the latest geological modelling with an estimation of a potential grade range sourced from all the drilling data for the lode intersections.
The Exploration Target comprises four distinct mineralised areas, termed Consols Deeps, Consols South, Perseverance Deeps and Perseverance East. The historical drill holes show continuity of the mineralisation at depth and along strike, with similar overall grades to the existing resource.
The Exploration Target is considered to be a medium term target. The intent is to continue exploration drilling along strike, down dip and down plunge from the current Mineral Resource to verify the Exploration Target. The Company intends to commence near mine exploration shortly after Completion, which will focus on extending the down dip and along strike extensions of the known deposit with the view to convert the Exploration Target into a Mineral Resource.
Geological Interpretation
The lode interpretations are based on 15m spaced section lines for Consols, 25m spacing for Fisher and Pinnacles and 50m for Perseverance. Digitising of the shapes involved snapping to drillholes on the assay grade dividers or on logged lithology if no assays were present. A 1% zinc or lead cut-off grade was used in conjunction with logged geology, with an allowance for minor internal dilution (generally <2m) on condition it made geological sense. The excellent underground mapping by Hopwood was also used to guide the design of the mineral lodes. In some minor instances, the gold assays were used to aid the interpretation particularly for the zinc lodes, which tend to be more gold-rich.
The chosen grade threshold was used in an effort to establish geologically sensible domains and take into account the likelihood of either an open pit or underground method of extraction. The mineralisation boundaries were variable in their visual sharpness, with some contacts clear cut and others more diffuse. The wireframes were used as constraints for the composite selection and grade interpolation.
No oxidation surfaces were designed mainly due to a lack of data and a lack of penetrative oxidation impacting the lodes. The recent Consols mining directly shipped any oxidised material to the Port Pirie Smelter to be used as a flux.
The existing interpretation honours all the available data; an alternative interpretation is unlikely to have a significant impact on the resource estimates.