Australian explorer Impact Minerals (ASX: IPT) is advancing a maiden drilling program at the Apsley target within its wholly-owned Commonwealth project in the Lachlan copper-gold province of New South Wales.
Nine reverse circulation (RC) scout holes for 2,500m have been completed to date to test a number of specific coincident induced polarisation (IP) geophysical and soil geochemistry anomalies first identified in mid-2020 and believed to be prospective for porphyry copper-gold deposits.
The holes have been drilled at widely-spaced reconnaissance intervals on four traverses between 200m and 400m apart, with up to three holes on each traverse.
Apsley’s core is surrounded by a halo of zinc-lead-manganese covering several square kilometres, and previously described as the textbook example of a “zinc doughnut”.
Impact said work so far has identified a wide variety of porphyry, volcanic and variably carbonaceous sedimentary rocks that, for the most part, dip west at shallow to moderate angles.
In some places, the porphyry units have a steeper dip, suggesting they may be later cross-cutting intrusions.
The rocks at Apsley are variably altered to chlorite, epidote, hematite and lesser biotite, containing disseminated pyrite and very fine-grained, weak-to-moderately disseminated copper-bearing minerals in zones up to 60m thick.
Some of the strongest alteration has originated from the centre of the area drilled, and follow-up work has been planned across the area along with drill testing of an additional three targets.
A hand-held x-ray fluorescence (XRF) instrument was used to measure major elements such as potassium, aluminium, iron and calcium, and indicate widespread alteration typical of the outer distal zones of a porphyry copper system together with more localised zones of potassic alteration typical of the inner more proximal zones of such systems.
Impact said measurements of precious metals such as gold and silver were not possible with the hand-held device and base metal readings including copper were taken as a single measurement on a bag of RC drill chips.
Accordingly, they have not been considered as reliable indicators of the true grade.
Impact is now awaiting laboratory assays for the precious and base metals as well as trace elements such as molybdenum, antimony and bismuth, which may help identify vectors to higher grade zones at depth or along trend.
The company has arranged for the samples to be assayed interstate to avoid excessive delays currently incurred by many NSW laboratories.
First assays are expected in early May.