The company said an update on feasibility work would be given shortly.
The latest drilling included an intercept of 658m grading 0.6% copper equivalent from 232m down hole, within which a 130m interval graded 0.9% copper equivalent from 662m.
Cortadera currently has an indicated resource of 471 million tonnes grading 0.46% copper equivalent.
"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," Hot Chili managing director Christian Easterday said in a market statement.
Hot Chili started the current quarter with A$28.3 million of cash.
Shares in Hot Chili were up 2% to $1.21 in morning trade, capitalising the company at $136 million.
