SCM Franke is located in the Atacama Desert, in the south of the Antofagasta province, Taltal region of Chile, 75 km north of Diego de Almagro town.
The claim areas belonging to Franke, include San Guillermo, Franke and Pelusa, and are located at an altitude of approximately 1,730 meters above sea level, within a radius of approx. 5 km from the SX/EW plant infrastructure.
Copper ore extraction from the Franke deposit has an almost 100-year history. Initially, the ore was extracted by independent miners called “pirquineros”, carrying out artisanal ore extraction from deposits at surface. In the second half of the previous century, the deposit was explored by many companies, but mining did not commence until 2009 when a new SX-EW plant was built.
KGHM Polska Miedź SA acquired the entire Franke mine as a part of the Quadra FNX acquisition in 2012.
Extraction of copper ore from the Franke pits is carried out using conventional methods typical for open pit mines, i.e. blasting and transporting the ore with haul trucks.
The ore is transported to crushing and agglomeration processes, and then deposited on heaps for leaching with a sulfuric acid solution. The copper-enriched solution obtained after leaching is directed to the extraction (SX) and electrowinning (EW) for production of high-quality copper cathodes - the final product of the process.
Geological units in the area correspond to the volcanic-sedimentary sequence deposited in tectonic basins. Lavas of andesite and basaltic composition, as well as marine and continental sequences of sedimentary rocks are dominant. Among the local igneous intrusions; diorites, monzonites and granodiorites can be distinguished, as well as numerous andesite dykes.
Rock alterations are heavily variable and do not cover large areas. Locally, it is a combination of enrichment with silica, carbonate and sodium, with varying proportions and intensity. Chloritization is common, as well as deeper parts epidotization of rocks.
Sometimes the rocks are influenced by regional metamorphism and hydrothermal changes.
In the Franke and San Guillermo areas, the copper mineralization is of the manto type, where lithology is the main factor controlling the spatial distribution of minerals. For the southern areas of the Pelusa concession, including the China Sur deposit launched in 2020, primary sulfide mineralization is associated with structurally controlled veins, stockwork, and the hydrothermal breccia of iron and copper oxides. The main tectonic structure responsible for mineralization was identified over a length of 750 m with an azimuth of 340°.
The main oxide minerals in the deposits are atacamite and chrysocolla. Among the sulfide minerals, in the eastern portion of the claim area, chalcocite with silver is dominant, while primary copper sulfides (mainly chalcopyrite, with minor bornite and locally coexisting covellite and chalcocite) dominate in the Pelusa area.
Exploration campaigns have been conducted continuously since 2010 and targeted both the increase of the quality of the identified ore bodies as well as the exploration of new areas of copper oxide mineralization in order to extend the supply of ore to the processing plant.
The identified resources of copper sulfide ore have attracted attention in recent years, due to a significant silver grade in the Franke and San Guillermo areas directly bordering the adjacent underground mine. Sulfide ore with a predominant occurrence of primary copper sulfides was also identified in the eastern areas at the Pelusa concession area.
Franke still holds areas prolific for further exploration campaigns targeted to explore new and expand already identified oxide and sulfide ore deposits.
A preliminary economic assessment is being conducted to evaluate the processing of sulfide ore both using the existing SX-EW infrastructure and financing the construction of a new flotation plant.