The company unveiled a positive preliminary economic assessment for its Vizcachitas copper-molybdenum project yesterday, which considered an openpit mine and plant and had assessed three mill throughput cases, of 55,000tpd, 110,000tpd and 200,000tpd.

It said the middle option would progress to prefeasibility, with the study expected by the end of 2020, because it delivered the best economic results and optimised the mining and technical aspects of the deposit.

The option was forecast to deliver an after-tax NPV (8% discount) of US$1.8 billion and an IRR of 20.77%, with initial capex of $1.87 billion for a 45-year mine and C1 cash costs of $1.36/lb in the first eight years.

Executive chairman Fernando Porcile, who was appointed last month, said the production plan would see only half of the 1.28 billion tonne resource grading 0.45% copper-equivalent depleted by the end of the mine life. 

"We are delighted with the results of this PEA which highlight the significant opportunity that the Vizchachitas project presents and, we believe, it will be Chile's next major copper mine," he said.

The 2014 study had prompted a reassessment after putting initial capex at $2.9 billion and the pre-tax IRR at 11.4%.

Los Andes said significant changes from the 2014 PEA included increased resources and projected long-term power prices dropping from $120/MWH to $45/MWH.

The company had C$2.7 million (US$2 million) in working capital at the end of March.

It last raised $8.8 million (US$6.8 million) in a placement at 33c per unit to Resource Capital Fund VI 12 months ago.

Its shares are at the upper end of the 52-week range of 15-35c, closing yesterday at 30c to capitalise it at $78 million (US$58 million).