Mineralization on the Los Filos Mine property is typical of intrusion-related gold–silver iron-oxide skarn deposits.

Los Filos Deposit Area Mineralization
In the Los Filos area, mineralization is associated with two early Tertiary granodiorite stocks that were emplaced in carbonate rocks and resulted in development of high-temperature calc-silicate and oxide metasomatic alteration (skarn) assemblages that were followed by distinct meso to epithermal alteration. Hematite and magnetite are typical skarn minerals, but diopside, which is usually recognized in skarn assemblages, is not present.

The Nukay and Sur deposits formed along the north and southern margins of the West Stock . The Peninsular and Zona 70 deposits formed on the northern and southwest margins of the East Stock, respectively.

The Los Filos Open Pit mineralization is hosted primarily within or on the lower contact of a diorite sill that dips from 20° to 50° to the east, away from the East Stock. The diorite was emplaced into a large, moderately dipping active structure that parallels bedding in the marble. The sill has a sigmoidal shape that starts out roughly flat at the stock, extends east at a moderate dip for approximately 200 m, turns south, flattens out, and extends to the Bermejal Intrusion, located approximately 2 km to the south.

Mineralization—Eastern Los Filos Open Pit
The diorite sill hosts a significant proportion of the mineralization on the eas ........

The Los Filos Mine Complex encompasses the three main open pit mining areas of Bermejal (BOP), Guadalupe (GOP), and Los Filos (LFOP), as well as three underground mines, Los Filos South, Los Filos North (LFUG) and Bermejal Underground (BUG).

Open pit mining entails conventional drilling and blasting, with loading by excavator and haulage by trucks to a crusher (for Crushed heap leach processing) or directly to a run-of-mine leach pad.

At LFUG, the overhand cut and fill (OHCAF) mining method is used in narrow areas and the overhand drift and fill (OHDAF) method is used in the wider areas. Longhole open stoping (LHOS) mining method is also used in targeted areas of vertical ore-body continuity and good rock conditions. The mining methods planned for BUG are OHDAF and underhand drift-and fill (UHDAF).

Open Pit Mining
The Los Filos Mine Complex comprises three open pit areas: LFOP, GOP, and BOP. Open pit mining is owner-operated, with conventional drilling and blasting. Loading is currently undertaken by shovels and front-end loaders (FEL), and haulage by 136-tonne trucks. A larger mining fleet is proposed to replace the existing equipment at the end of their useful life. Benches are 9 m high with safety berms every second bench (i.e., double-benched to 18 m).

Ore (Crush) is hauled either to the crusher, for crushed heap leach, or directly to an ROM leach pad for processing. A 10,000 t/d CIL processing plant is planned to be constr ........

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