Drill results at Camino Rojo Sulphides continue to support potential for underground development
Drilling continues to intercept wide zones of higher-grade gold mineralization, and in conjunction with metallurgical results from the 2021 drilling (see news release dated May 9, 2022), supports the potential for underground development and a standalone processing option for the Camino Rojo Sulphides. A large part of the 2022 program included infilling the sulphide deposit and improving the geological model to support potential underground mine development scenario. A total of 9,174 metres was completed in 15 holes, with 5 holes previously reported (see news release dated September 12, 2022 - Orla Mining Advances Exploration & Growth Pipeline). The 15 holes completed in 2022 returned 32 significant mineralized drill intercepts with grade-by-thickness factor greater than 50 g/t by metre Au (g/t * m), including 16 intercepts with grade-by-thickness factor greater than 100 g/t by metre Au. Full drill results are available in Appendix news release date January 31, 2023, and at www.orlamining.com.
The current mineral resource estimate for the Sulphide Project at Camino Rojo consists of 74 koz of measured resource (3.358 million tonnes at 0.69 g/t gold) and 7,221 koz of indicated resources (255.4 million tonnes at 0.88 g/t gold) and has an effective date of June 7, 2019.
- Hole CRSX22-09B: 4.66 g/t Au over 64.0 m
- Hole CRSX22-09A: 2.76 g/t Au over 79.0 m, incl. 3.22 g/t Au over 55.0 m
- Hole CRSX22-08C: 2.81 g/t Au over 70.0 m
- Hole CRSX22-10A: 1.92 g/t Au over 87.0 m, incl. 3.14 g/t Au over 25.5 m and 1.74 g/t Au over 73.5 m, incl. 2.61 g/t Au over 24.0 m
- Hole CRSX22-09: 3.83 g/t Au over 40.5 m, incl. 9.28 g/t Au over 9.0 m and 6.94 g/t Au over 16.0 m
- Hole CRSX22-08B: 3.78 g/t Au over 37.0 m
- Hole CRSX22-10: 2.71 g/t Au over 49.5 m, incl. 6.80 g/t Au over 8.0 m
Vein domains constraining higher grade gold in sulphide deposit
The 2022 sulphide drill program has helped define areas of high vein concentrations (“vein domains”) which coincide with higher grade (>2 g/t) gold mineralization. The vein domains are important geological controls on gold mineralization, constraining the distribution and continuity of higher-grade gold mineralization within the sulphide deposit. Improved confidence in geological controls will strengthen future mineral resource estimations.
Vein domains have been defined by combining recent oriented diamond drill core data and approximately 70,000 m of historical vein density and orientation data within the main zone of potassic alteration (Kp). This work has resulted in the definition of three steep northwest and five shallow south-southwest dipping vein domains. High grade gold (>10 g/t Au) appears to be concentrated at the intersection of these steep and shallow dipping domains.
Deeper intersections suggest deep potential for extension of Camino Rojo Sulphides
Select holes from the recently completed 2022 sulphide drill program were extended to test the down plunge continuity of gold mineralization along the Dike Zone. These drill holes have returned encouraging and highly significant results, such as 4.02 g/t Au over 22.9 m. Compilation of historical drill data has also confirmed high-grade gold intercepts over significant widths with a similar style of mineralization elsewhere below the current extents of the Camino Rojo resource estimation model.
Most of the gold mineralization at Camino Rojo has been defined in the Caracol Formation where auriferous veins are mostly constrained to a broad envelope of potassic alteration (Kp). Recent and compiled historical drilling indicates gold mineralization extends deeper into the underlying Indidura and Cuesta del Cura formations (and potentially deeper into other underlying units) along the Dike Zone and Breccia Fault Zone, suggesting these faults may be feeder-like structures for the Camino Rojo deposit. This deeper gold mineralization is hosted by skarn and calc-silicate alteration associated with manto-type mineralization with semi-massive to massive sulphides replacing bedding.
2022 notable results hosted in Indidura or Cuesta del Cura formations:
- Hole CRSX22-07: 4.02 g/t Au over 22.9 m, incl. 9.30 g/t Au over 6.1 m
- Hole CRSX22-08B: 1.28 g/t Au over 24.6 m
- Hole CRSX22-08B: 1.33 g/t Au over 17.2 m
- Hole CRSX22-08C: 2.50 g/t Au over 9.1 m
- Hole CRSX22-08C: 1.81 g/t Au over 19.4 m, incl. 2.51 g/t Au over 9.0 m
Selected historical results below Caracol Formation in Indidura or Cuesta del Cura Formations:
- Hole CR12-366D: 4.04 g/t Au over 46.5 m, incl. 6.26 g/t Au over 27.0 m
- Hole CR13-507DB: 3.08 g/t Au over 55.5 m, incl 5.67 g/t Au over 22.5 m
- Hole CR13-455D: 6.12 g/t Au over 21.0 m, incl 18.75 g/t Au over 6.0 m
- Hole CR13-454D: 2.11 g/t Au over 51.0 m, incl 6.72 g/t Au over 4.5 m
- Hole CR13-453D: 3.62 g/t Au over 27.0 m
- Hole CR14-597DG: 3.68 g/t Au over 25.5 m incl 11.49 g/t Au over 6.0 m
Camino Rojo Sulphides drilling continuation
A 34,000-metre, 57 hole follow-up drill program will continue to infill the Camino Rojo Sulphides in 2023. 20% of the holes will extend to test the deep potential of the deposit. In addition, 6,500m will be drilled on the extensions of the Camino Rojo oxide deposit to update and expand resources and reserves.
Based on the positive results encountered in the 2021 and 2022 programs, more closely spaced, south-oriented drilling will be required to fully capture the extent of a potential underground resource. To date, 15,253 metres of directional drilling has been completed. This drilling has continued to inform Orla’s perspective on the development approach to the deposit. The 2023 drilling is expected to strengthen the confidence for the development of a Preliminary Economic Assessment (“PEA”) that contemplates underground mining by infilling the higher-grade (>2 g/t) portions of the deposit with 50 metre spacing of South-oriented drill holes. Overall drill spacing at the end of this next phase, including historical north-oriented drill holes, will be 25-30 metres. Upon the completion of the 2023 additional south oriented directional drilling and test work programs, a PEA is expected to be completed based on the optimal development scenario for Orla.