Production at La Colorada has been ongoing since 2012 with the majority of ore being sourced from the Gran Central open pit. Mining ceased in Gran Central in 2018 and production is sourced from the El Creston and Veta Madre open pits.
Pit Design
The open pit designs were created by Argonaut regional staff in Hermosillo and transferred to La Colorada for implementation by both operations and mine contractors. Mine design is comprised of four mine phases. The first was mined and finished in 2019 and Phase 2 was finished in 2020. Phase 3 is actively being mined and Phase 4 is the final layback. Veta Madre consists of four phases for eventual extraction and Phase 1 is actively being mined. Phases 2 and 3 will extend the open pit to the west and Phase 4 will be the final layback.
For the El Crestón and Veta Madre pits, the ramp width was sized at 25 m (truck factor of 3.5) which can safely support Cat 777 (or equivalent) sized mining trucks. One-way access of 15 m was applied at the pit bottom after stripping requirements were met.
El Crestón Pit Parameters:
Inter-ramp Slope: 51°, 41°, 49°, 46º;
Bench Face Slope: 67°, 65°, 70°;
Berm Width: min.5 m max.7 m;
Bench Mining Height: 5 m;
Bench Height: 15 m;
Ramp Width: 2 Ways 25 m;
Ramp Width: 1 Way 15 m;
Ramp Gradient: 10%.
Veta Madre Pit Parameters:
Inter-ramp Slope: 46º, 48°, 51º, 53º;
Bench Face Slope: 67°;
Berm Width: 7 m;
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