Lundin Mining announces new copper-gold Saúva Discovery at Chapada

As part of Lundin Mining’s ongoing exploration programme aimed at increasing the mineral resource estimation at Chapada, diamond drilling was initiated at Saúva in 3Q21 within a recently acquired exploration concession. Initial drilling was designed to test for the source of a strong soil copper anomaly (>1000 ppm copper [Cu]) that was located along strike from the previously identified Formiga prospect. The first two drill holes at Saúva confirmed the presence of shallow high-grade copper-gold mineralisation. Further drilling was undertaken to evaluate the potential and to date a total of 47 holes have been completed defining a mineralised area measuring approximately 750 m x 650 m, with assay results available for 29 holes. The mineralisation currently remains open in all directions.

Highlights from initial drilling include:

• Hole FOR-113: 55.48 m at 0.88% Cu and 1.15 g/t gold (Au) or 1.72% copper equivalent (CuEq), from 6.52 m, including:
  • 27.26 m at 1.3% Cu and 1.89 g/t Au or 2.68% CuEq, from 33.74 m.
• Hole FOR-115: 65.45 m at 0.61% Cu and 0.7 g/t Au or 1.12% CuEq, from 23.55 m, including:
  • 18.41 m at 1.26% Cu and 1.92 g/t Au or 2.66% CuEq, from 50.43 m.
• Hole FOR-123: 64.25 m at 0.72% Cu and 1.1 g/t Au or 1.51% CuEq, from 158.45 m, including:
  • 43.25 m at 0.9% Cu and 1.52 g/t Au or 2.01% CuEq, from 158.45 m.
  • 70.4 m at 0.42% Cu and 0.11 g/t Au or 0.50% CuEq, from 248.70 m, including:
    • 8.56 m at 1.04% Cu and 0.16 g/t Au or 1.16% CuEq, from 248.7 m.
• Hole FOR-135: 57.31 m at 0.79% Cu and 1.06 g/t Au or 1.56% CuEq, from 8.29 m, including:
  • 17.95 m at 1.27% Cu and 1.98 g/t Au or 2.71% CuEq, from 32.05 m.
  • 12.8 m at 0.44% Cu and 0.11 g/t Au or 0.52% CuEq, from 189.20 m.
• Hole FOR-148: 74.06 m at 0.81% Cu and 1.27 g/t Au or 1.74% CuEq, from 116 m, including:
  • 19.39 m at 1.8% Cu and 3.61 g/t Au or 4.43% CuEq, from 149.61 m.

Lundin Mining President and CEO, Peter Rockandel, commented: “The shallow and high-grade copper-gold mineralisation discovered at Saúva is a clear example of the growth optionality that stems from Lundin Mining’s successful track record of aggressive near-mine and brownfields exploration at all of our operations. Implications that this new high-grade mineralised system may have for our on-going expansion studies of Chapada will be evaluated as this discovery evolves during the year.”

Ciara Talbot, Vice President, Exploration, added: “We are very pleased with this early-stage discovery within the exploration concessions identified and acquired as part of last year’s federal auction process. This discovery supports our view that numerous opportunities exist to increase the size and quality of our mineral resource base at Chapada.”

Saúva Discovery

In 2015, the Chapada exploration team identified the Formiga exploration target, approximately 15 km north of the mine, based on positive chip sampling and regional mapping. The first drill holes at Formiga intercepted skarn style alteration comprising hydrothermal assemblage of garnet-epidote-amphibole-diopside in metasedimentary rocks. Then, during soil sampling in the region in 2016, additional disseminated copper-gold targets in the Formiga sector were identified along strike in metadiorite with hydrothermal alteration similar to what is being mined at Chapada. This trend of mineralised occurrences appeared to extend off the exploration concession to the west.

Following the acquisition of Chapada by Lundin Mining in 2019, a mineral inventory range analysis study was undertaken to refine the exploration strategy, including the prioritisation of potential mineral concession acquisitions ahead of the anticipated federal auction. In 1H21, Lundin Mining acquired 37 new exploration concessions through the auction process, covering 58 048 ha. and increasing the total land position around the Chapada mine by over 120%. This included the concession immediately west of Formiga. Two initial drill holes, FOR-112 and FOR-113, were designed to test for the source of a strong soil copper anomaly (>1000 ppm Cu) on this newly acquired concession along strike from Formiga. Both drill holes confirmed the presence of shallow high-grade copper-gold mineralisation, which has become the Saúva prospect discovery.

Saúva exploration results

Following the initial discovery of the Saúva in September 2021, an aggressive exploration drilling campaign was commenced with five drill rigs to better define the potential size of the discovery. 43 drill holes, totalling 12 850 m, had been completed at Saúva as of December 2021. Almost all drill holes intercepted the mineralised layer containing high chalcopyrite with (±) bornite content and with the majority returning intersections with grades above 1% CuEq, confirming the potential for significant, shallow and high-grade copper-gold mineralisation. The mineralisation continues to remain open in all directions.

Mineralisation at Saúva is comprised of disseminated and vein-hosted bornite and chalcopyrite hosted by biotitic and quartz-feldspar altered rocks. The high-grade mineralisation (> 1% CuEq) is associated with bornite greater than chalcopyrite, or chalcopyrite greater than bornite sulfide zones. Lower grade mineralisation (> 0.3% CuEq) is associated with chalcopyrite and pyrite and chalcopyrite sulfide zonesThe hydrothermal alteration zone is currently interpreted to generally follow a northeast trend, but individual high-grade orientations vary and detailed modelling remains in progress.

2022 exploration programme

Lundin Mining is evaluating and interpreting the results and continues to explore for extensions to the mineralisation. There are presently three rigs drilling in the Saúva sector testing areas to the northeast and west of the discovery area. Aggressive and methodical exploration of the sector is planned for 2022 as part of the US$10 million exploration programme at Chapada. Additional drill rigs and approximately 50 holes are planned to test northeast along strike to towards the Formiga sector, as well as step out in other directions.

Read the article online at: https://www.globalminingreview.com/exploration-development/14022022/lundin-mining-announces-new-copper-gold-sava-discovery-at-chapada/