Three underground mining methods were selected for Buriticá; longhole open stoping (LHOS), cut & fill (C&F), and shrinkage stoping. Mining method selection was driven primarily by geomechanical rock quality, vein geometry, depth, proximity to old workings, stope margin and vein continuity. Unless geomechanical and geometry characteristics required either C&F or shrinkage, longhole mining was the preferred mining method due to higher productivities and lower mining costs compared to either C&F or shrinkage.
There are two vein systems that will be exploited in the Buriticá mine: Yaraguá and the Veta Sur.
The Yaraguá system generally strikes to the east, and has been drill intersected over 1,125 m along strike and 1,540 m vertically. There are several veins within the system that strike to the northwest, intersecting the east-striking veins. Vein strike lengths vary from 50 to 1,100 m and vein dip distances vary from 50 to 1,300 m. The Veta Sur system strikes to the Northeast, and has been drill intersected over 1,140 m along strike and 1,600 m vertically. Vein strike lengths vary from 70 to 1,000 m, and vein dip distances vary from 150 to 1,350 m.
Cemented backfill will be used to fill stope voids to provide confinement on the waste rock pillars in the hanging wall and footwall between parallel stopes spaced close together, and as the fill develops strength, to reduce lateral loads on these pillars. This is an important aspect when mining close ........
