Rubix Resources Limited announced the results of assays from drilling at its 100% owned Paperbark Project, Queensland. The completion of a six hole (1,470m) blended RC and diamond drilling program was announced on 13 September 2022. Drill chips and core contained visual copper mineralisation, lead and zinc sulphides in five of the six holes drilled across the Paperbark project area.

Two holes were drilled at the JB Zone Prospect for a total of 650m. Drilling was designed to understand the potential to expand the existing Exploration Target1 at the JB Zone and determine the potential size of the mineralising system. Both drillholes were positioned at least 180m from the nearest historic drillhole.

Both holes encountered Pb-Zn mineralisation at the expected target depth (approximately 200m downhole). Overall, the results are consistent with the previously reported visual estimates and historic drilling. Results affirm that the zinc mineralisation at the JB Zone comprises a thick, approximately stratiform zone of diffuse low-grade mineralisation containing several thinner, relatively `high grade' horizons.

The results suggest that mineralisation is predictable along-strike and that further drilling may expand the size of the Exploration Target. Further, the results suggest that the JB and JE Zones may form a predictable, (semi) continuous mineralised `blanket'. The distance of Rubix' new holes from the Bream Fault suggest that the nearby Dhufish Fault, as well as faults further east, may be equally prospective for zinc mineralisation.

Rubix included cadmium (Cd) in its assays to assess other targets in the project area and the nature of mineralisation. Previous work suggested that the JB Zone lacked the Mn-Cd-Tl geochemical association that accompanies mineralisation at nearby high-grade Pb-Zn deposits including Century, Lady Loretta and McArthur River. The results reported show that elevated Cd (>50 ppm) corresponds with zinc grades >1% (downhole) at the JB Zone.

Further, limited testing of a surface geochemical anomaly to the east of the JB Zone - coincides with elevated levels of Cd (up to 53 ppm) and Mn. Given the relationship between elevated Cd with Zn at the JB Zone, this surface anomalism may indicate the presence of Zn mineralisation at Fox > 1% Zn. A lack of Cd-Mn surface expression at the JB Zone may reflect the relatively deep nature of mineralisation at this location.

Away from the JB Zone, the Fox Anomaly has one of the most significant surface zinc expressions in the project area (defined by Zn > 2000 ppm) in historic soil, stream sediment and rock chip samples. The Fox Anomaly covers an area of Zn and Cu anomalism more than 1.5 km in length, and 800m in width, discovered by North Limited in 1995. In addition to Zn, RMG Limited proposed a link between zinc anomalism at Fox (up to 3,990 ppm Zn) and elevated cadmium (Cd), thallium (Tl) and manganese (Mn) in soil and rock chip samples.

This is like geochemical associations described for the Century, Mount Isa, Lady Loretta and McArthur River deposits. The geochemical haloes of Century, Lady Loretta and the McArthur River deposits feature a predictable chemical zonation of carbonate minerals approaching the ore zone. Typically, carbonates increase in Mn content towards the ore zone both along- and across-strike4 in a halo up to 250m from the deposit, with the Mn content of dolomites showing a systematic increase towards the ore lenses5.

Manganese shows the broadest dispersion halo associated with the deposits, making it a suitable regional pathfinder element. While Cd is not routinely assayed, the available data with the most significant Cd anomalism occurs together with elevated Mn at the Fox (and Tasman) Anomaly, correlating with Zn anomalism. Geochemical assays presented here have identified a correlation between cadmium and zinc grades at the JB Zone, where increased zinc is accompanied by increases in cadmium.

Cadmium (Cd) behaves in a geochemically similar way to zinc, so may substitute for Zn in the sphalerite (zinc sulphide) crystal lattice. Using Cd and Mn as pathfinder elements, the company suggest that the Mn anomalism at Fox may represent the expression of a geochemical halo associated with buried Zn mineralisation. Further, the coincidence of elevated Cd and Zn with Mn anomalism at the surface at Fox may indicate that zinc mineralisation may be present at shallower depths than at the JB Zone, where available Cd analyses are at (or below) detection limits.

Six holes drilled by MIM near the Fox Anomaly to a maximum depth of 150m (BB081RC-BB086RC), generally returned Zn > 1000ppm in the top 30-50m of each hole6. However, RMG considered that these holes did not adequately test the anomalism and that MIM did not recognize the possibility of fault-controlled mineralisation or a deeper Gunpowder Creek Formation target. No further work has been done at Fox.

Based on the visual assessment of copper sulphides visible in core, a subset of samples was assayed from holes drilled at the Grunter North Prospect. This selection from the three drillholes (GN22-01 to GN22-03) were submitted together with the JB Zone prospect samples to ALS Laboratories. Assay results were generally consistent with visual estimates, with best results of 1.06% Cu achieved from 78-79m downhole depth in GN22-01.

The results are comparable to the historic data at Grunter North and the source of copper oxide mineralisation at surface remains enigmatic. The Paperbark Project in northwest Queensland comprises EPM 14309, held 100% by Rubix, and is known to contain stratiform, epigenetic-style low to moderate grade lead-zinc (Pb-Zn) mineralisation, and is prospective for copper (Cu) mineralisation. The project is situated in the Lawn Hill Platform of the Western Mount Isa Inlier, a highly prospective base metals region.

The EPM encompasses the same geology which is host to the Century, Mount Isa, George Fisher and MacArthur River giant Pb-Zn deposits. The project is located approx. 25km to the south-east of the Century zinc deposit.