Los Filos Mine Complex

The Los Filos mine complex began commercial production in 2008 and was acquired by Leagold in 2017. The operation consists of two open pit mines – Los Filos and Bermejal – and an underground mine at Los Filos. Los Filos is located 180 km south of Mexico City in the municipality of Eduardo Neri, Guerrero State, Mexico. The property is accessible by paved road and an on-site airstrip and includes 39 concessions covering 148,908 hectares. 

Production in 2019 totalled 201,000 oz of gold. Gold is recovered from crushed and run-of-mine ore via a conventional, low-cost heap leach and ADR (adsorption-desorption-recovery) process. Infrastructure on site includes primary and secondary crushing plants with 18,000 tpd capacity, an overland conveyor system, an agglomerator, two heap leach pads (one for ROM and one for crushed ore, with associated conveyors and stackers), two pregnant solution collection ponds (one for each heap), one recirculation pond and two contingency water ponds, and an ADR plant and gold refinery. 

An independent feasibility study completed for Leagold in March 2019 outlined the potential to increase gold production at Los Filos to more than 400,000 oz/year. Expansion opportunities include development of the Bermejal underground mine, an enlarged Los Filos open pit mine, the re-phasing of the Bermejal open pit into two distinct sections (Bermejal and Guadalupe) and the construction of a 4,000 t/d carbon-in-leach (CIL) plant.

Geology and Mineralization

Los Filos is located near the center of the Morelos-Guerrero Sedimentary Basin, a thick sequence of Mesozoic platform carbonate rocks. Mineralization is typical of intrusion-related gold-silver skarn deposits and is associated with two early Tertiary granodiorite stocks that were emplaced in carbonate rocks. Mineralization being mined at the Los Filos open pit is associated with a shallowly east-dipping sill and with the upper portion of the east stock. The Los Filos underground is divided into the Los Filos Norte and Sur sectors along the north and south side of the circular west stock. Mineralization in the Bermejal area consists of mineralization along the contact of the Bermejal stock with the carbonate rocks of the Morelos Formation. The Bermejal open pit mineralization is typically at the top or on the flanks of the upper portion of the intrusive. Mineralization extends below the Bermejal open pit and down the steeply dipping to vertical flanks of the intrusive. At the northern end of the intrusive the mineralization is referred to as the Bermejal underground deposit.

Location of the Los Filos Mining Areas and Mineral Deposits