Frontera Copper Corporation built the Piedras Verdes Mine and started commercial production in 2006.

It was capital constrained, mining was subcontracted at a high cost and leaching was undertaken on a run of mine basis with poor metallurgical recoveries.

In the context of low copper prices prevailing during the financial crisis, it suspended operations in 2008. Invecture Group made a tender offer for all of Frontera’s shares that was successfully concluded in May 2009

Invecture Group invested over $450m to convert the Piedras Verdes Mine from a run of mine heap leach operation to multiple process streams, increasing production and reducing unit costs

Kupari Metals built a floatation plant adjacent to the Piedras Verdes deposit and started operations in 4Q12, this provided Frontera with the ability to monetize certain ore types offering better economics when processed by floatation

From 4Q19 through 2Q21, Piedras Verdes was placed under Care and Maintenance in the context of low copper prices. During this time many operational improvements were identified, analyzed and testwork was undertaken.

As a result, over the past 18 months,
Piedras Verdes has:

We expanded the mineral reserve from 628kt of contained copper to 934 kt with
a combination of exploration drilling and by developing an NSR driven block model at $3.50/lb copper

Grown and optimized operations by

Expanding the capacity...

Expanding the capacity of the leach crushing and screening and conveying system in 1Q22 to operate at 40 ktpd and 45 ktpd by 3Q22 enabling improved recoveries and kinetics, with higher throughput to the agglomerators.

Developing the engineering...

Developing the engineering for agitated tank leaching of 18Mt of tails over 10 years at an average CuSEQ grade of 0.13% that will start construction in late 2Q22 and be commissioned in 4Q22.

Installing two agglomerators...

Installing two agglomerators in 1Q21 with a capacity of 24 ktpd to create robust agglomerate pellets from screened fines with acid and raffinate|water to enhance leach recoveries and kinetics, eliminate the loss of contained copper in slimes confined to tails by the screw slurry classification system it replaced and reduce water consumption.

Optimizing acid consumption...

Optimizing acid consumption with continuous remote monitoring of heap leach solution chemistry and selective acid addition by section of leach pad.

Internally developing a mobile...

Internally developing a mobile fleet dispatch system that optimizes operations, enables real time monitoring of equipment productivity and automates data capture for multiple systems.

Selectively implementing heap...

Selectively implementing heap leach aeration, maximizing copper recovery, kinetics and acid generation.