Table 1. Drilling summary to 2022 Year end

Figure 2. Copper soil geochemistry and drill hole location

Figure 2 above shows the soil copper geochemistry and the position of the three drill holes. It demonstrates the extent of the copper anomaly and the limited sub surface testing accomplished to date.

CDH001 intersected 82m at 0.90% Cu and 199ppm Mo within a broader interval of 808m of 0.42% Cu and 79ppm Mo. The Figure below is a cross section of the drill hole with bundled assays included.

Figure 3. Schematic cross section for CDH001 with assay intervals  tabulated.

CDH002 was collared 400m south of CDH001. It intersected 172m of 0.74% Cu and 78ppm Mo within a broader interval of 754m of 0.46% Cu and 76ppm Mo from a down-hole depth of 152m. A near surface mineralized zone of 70m of 0.29% Cu and 50ppm Mo was intersected from 18m.

Figure 4. Schematic cross section of CDH002 with assay intervals tabulated.

CDH003 was paused at 300.6m in December in strong porphyry mineralisation. As stated above it was planned to extend to 1300m. CDH003 intersected 144.6m of 0.69% Cu and 155 ppm Mo from 156m to 300.6m. It also intersected a near surface mineralized zone of 148m of 0.20% Cu and 65 ppm Mo from 8m, which included 60m of 0.27% Cu and 57 ppm Mo. This shallow intercept is interpreted as the continuation of the same shallow mineralization intersected in CDH002 (70m of 0.29% Cu and 50 ppm Mo).

Figure 5. Last drill core tray CDH003 before drilling suspension. Shows dominant bornite (dark colour) in classic porphyry veining with lesser chalcopyrite in diorite porphyry. The interval 298.0m to 300.6m assays 2.69% Cu, 151 ppm Mo, 7.3 ppm Ag

Cobrasco mineralization is bornite dominant with lesser chalcopyrite and molybdenite. Penalty elements (particularly arsenic) are low. Such mineralization would be expected to be amenable to the production of a high-grade copper concentrate using traditional mineral processing. Preliminary metallurgical testing will be conducted on the completion of the current drilling program.

Drilling results and mapping/sampling support our interpretation that Rugby has discovered a major copper-molybdenum porphyry system.  The system includes a cluster of porphyry centres within a north westerly trending structural corridor, a feature observed in other western Andean porphyry systems.

The area located one kilometer north of the porphyry mineralization drilled to date with elevated molybdenum geochemistry was geologically evaluated. Molybdenum often denotes the locus of a porphyry copper-molybdenum system. Prospective bornite-molybdenite veining in porphyritic rocks were mapped and sampled.

Figure 7 (a) Quartz-pyrite-chalcopyrite stockwork from recent landslide, and 7(b) rhyolite with molybdenite-malachite veinlets

A large magnetic low is centred some two kilometers east of the drilled porphyry (Cobrasco East). Copper- gold rich breccia boulders from the streams draining this magnetic low target suggest possible evidence of another sizeable porphyry body awaiting discovery. As previously noted, the magnetic low may be due to magnetite destruction of associated with a mineralizing event.

Figure 8(a) Location of samples from eastern copper gold porphyry system

Figure 8(b) Location of magnetic low with superimposed anomalous copper gold porphyry rock/float samples.  

Proposed Drill Program

Drilling is expected to resume H2 2024 and will continue CDH003 to its planned depth of 1300m. The results from that hole will establish drill priorities going forward.

A Strategic Opportunity

The Cobrasco discovery comes at a time when economies are starting to recognise a dire shortage of copper is inevitable when moving into a more electrified world based on renewable energy sources. Only in recent weeks are copper prices advancing as predicted. For the most part junior explorers like Rugby are yet to see the capital appreciation necessary to finance large programs such as is justified by the Cobrasco discovery. That being the case, Rugby as with other juniors has had to accept a stalled program and/or unacceptably high capital dilution.

Rugby has demonstrated that Cobrasco is an exceptional exploration opportunity by industry standards. That is based on the potential size and grade of the porphyry system.  Such a system requires some 50,000 to 100,000 meters of drilling to evaluate the deposit(s). The drilling costs are made more onerous due to the use of helicopters for access. Fortunately Rugby is well positioned to secure a financing relationship with a major company/institution to take the project forward. That initiative is in progress.

Drill Permitting in Western Colombia

As with other projects in the region, Rugby’s two Cobrasco concessions fall within a very large Forestry Reserve that encompasses the western side of Colombia.  Prior to 2022 mineral exploration in the region required a Forest Reserve Extraction for those sites where drilling was to be undertaken. In January 2022, a Resolution was passed allowing for drilling where specific environmental requirements are met. Rugby is meeting those requirements and expects to be able to meet those requirements going forward with drilling.