Atico Updates Mineral Reserves and Resources for the El Roble Mine in Colombia - Seite 3

Resource and Reserve Estimation Methodology

The Mineral Resource estimation considers channel and core samples, in addition to the underground mine mapping for the construction of three-dimensional wireframes of the lithology and mineralized bodies. Estimation of grades in the block models only considers samples located inside the mineralized bodies solid, which are applied to anomalous grade or top cut treatment and a further compositing process. The model was constructed using 2m x 2m x 2m blocks, which represents the selective mining unit (SMU). The orebodies estimation is conducted separately body by body and element by element (Cu and Au). The methods used for grade estimation are cubic inverse distance (Goliat, Maximus and Maximus Sur Orebodies) and Ordinary Kriging (Zeus Orebody).

A density factor specific for each ore-body was assumed for conversion of block volumes to tonnes (Goliat = 3.34t/m3, Maximus = 3.50t/m3, Maximus Sur = 3.26t/m3, Zeus = 3.53t/m3). Mineral Resources are reported to 0.88% CuEq cut-off. For each block, the CuEq value was calculated by multiplying one tonne of mass of each by block grade by its average recovery, metal payable recovery and metal price. Blocks with CuEq grade higher than the CuEq cut-off were included in the resource estimate.

Proven and Probable Mineral Reserves were derived from the Measured and Indicated Resources by applying modifying factors related to mining methods, mining dilution and historical operating costs detailed as follows: mining (US $56.94/t), processing (US $15.95/t), general services (US $7.89/t), on-site administration and indirect (US $14.03/t), selling and concentrate shipping (US $9.63/t). Operating costs total US $104.44/t and comprise the lower NSR value for reserve reporting purposes. Mining dilution was estimated at variable percentages depending on the mining activity and labour, and ranges from 3.5% for breasting within the ore-body to 13.5% for crown pillar recovery.

The resource and reserve models have been validated by reconciliation against actual mined production continuously for several years with reconciliation results being acceptable for all ore bodies that have experienced a significant amount of production.

A full NI43-101 report authored by Mr. Thomas Kelly will be available on www.sedar.com within 45 days of this news release.

El Roble Mine

The El Roble mine is a high grade, underground copper and gold mine with nominal processing plant capacity of 1,000 tonnes per day, located in the Department of Choco in Colombia. Its commercial product is a copper-gold concentrate.