STOCKHEAD | Special Report | 20 May 2022
Pic: Frantic00/iStock via Getty Images
The Cortadera porphyry deposit continues to deliver the high-grade goods for copper developer Hot Chili, with the latest drilling program from the development striking a massive hit of 658m at 0.6% copper equivalent.
That’s a good grade over a very wide width for a porphyry, where copper resources far lower in grade can be cash cows thanks to their incredible scale.
Cortadera is part of Hot Chili’s (ASX:HCH) Costa Fuego, one of the only low altitude copper developments globally with a near term development timeline.
The strike of 658m at 0.4% copper, 0.2g/t gold and 122ppm molybdenum came from just 232m downhole, with narrower intersections of 134m at 0.8% CuEq, and 130m at 0.9% CuEq from 470m and 662m depth at the main Cuerpo 3 porphyry.
Those results in hole CORMET005 are the latest example of Cortadera’s capacity to outperform expectations.
“The PFS in-fill drill programme across Cortadera has collected important geotechnical and hydrogeological information and has also continued to define and expand high grade resources,” HCH managing director Christian Easterday said.
“Upgrading our resources with wide drill intersections grading 0.8% to 1.0% copper equivalent is a great outcome, which demonstrates the quality and growth potential of Costa Fuego as one of the only low-altitude, material, copper developments in the world capable of near-term development.”
High grade continues to expand
Hot Chili, which has an offtake partnership with one of the world’s largest metals traders in Glencore to back its plans to enter production at the proposed Chilean mine, has an indicated and inferred resource at Cortadera of 451Mt at 0.46% CuEq including 2.086Mt of copper equivalent metal and 1.663Mt of copper and 1.9Moz gold in the ground.
That’s on top of a 273Mt resource at the nearby Productora at 0.52% CuEq for 1.215Mt Cu and 810,000oz Au.
But development study drilling at Cortadera ahead of a planned PFS continues to highlight opportunities to grow its high grade resource, with multiple wide and high grade strikes outside the existing resource.
That includes 30m at 1.4% CuEq (1.1% copper, 0.5g/t gold and 165ppm molybdenum) from 690m in hole CORMET005, which is outside the current high grade resource (anything above 0.6% CuEq).
It builds on recently reported drill results from Cuerpo 3 including 552m at 0.6% CuEq from 276m deep, including 248m at 0.8% CuEq, and 876m at 0.5% CuEq from 246m, including 206m at 0.9% CuEq.
Diamond drill hole CORMET002 has also returned 370m at 0.4% CuEq (0.3% Cu and 0.1g/t Au) from surface at the Cuerpo 2 porphyry, including 20m at 0.8% CuEq from 24m and 22m at 1% CuEq from 136m depth. The high grade intersections are both outside the current high grade resource at Cuerpo 2.
A final development study drill hole is still being completed at Cortadera, with four metallurgical diamond drill holes completed at the Productora orebody.
Productora also contains a probable ore reserve of 166.9Mt at 0.43% copper, 0.09g/t gold and 138ppm molybdenum for 716,800t of contained copper metal, 470,700oz of contained gold and 23,100t of molybdenum with payable metal of 562,900t Cu, 191,900oz Au and 11,200t Mo.
Satellite drilling under way
The scale of Costa Fuego is such that there are multiple deposits likely to be developed once the mining operation is under way.
Just 5km northeast of Cortadera, Hot Chili boasts the San Antonio and Valentina deposits, two high grade satellite orebodies where HCH plans to grow its resources through drilling.
Ten drill holes are planned at Valentina, where drilling is already under way, with another 13 to be sunk into San Antonio. Both are expected to be part of Costa Fuego’s next resource upgrade and its combined PFS open pit mine schedule this year.
San Antonio already boasts a maiden inferred resource reported in March of 4.2Mt at 1.2% CuEq (1.1% copper and 2.1g/t silver) for 48,000t of copper and 287,000oz of silver.
Meanwhile platform and access clearing is expected to be complete in the coming week at the Santiago Z exploration target, another high quality copper prospect at Costa Fuego.
Drilling will commence at Santiago Z after Hot Chili wraps up at Valentina and San Antonio.
Located immediately south of Cortadera, soil results and mapping have confirmed a large potential copper porphyry footprint at the Santiago Z measuring over 4km in length and 2km in width.