Molybdenum output for the year was 1.3Mlb

But the tailings, in terms of tonnage and grade, were better news for the red metal, the company said.

The copper cash cost was US$1.75/lb against the annualised average LME copper price for 2021 sitting at US$4.22/lb.

But 2022 guidance from the company anticipated rising costs across Amerigo's operations.

Amerigo has developed a Chilean copper plan that involved tailings treatment rather than mining.

Its 100% owned Minera Valle Central (MVC) operation near Rancagua, Chile, has been producing copper concentrates since 1992 by processing fresh and historical tailings from Codelco's El Teniente mine, the world's largest underground copper mine. 

Amerigo has now completed the development of the historical high-grade Cauquenes tailings deposit, an investment that has enabled MVC to produce substantially more copper at lower cash cost until at least 2037. 

President and chief executive officer Aurora Davidson said the high copper price in 2021 resulted in a "transformational" year for Amerigo, which was consequently able to put in place quarterly dividends and share repurchase initiatives.

Guidance for 2022 was slightly lower than the 2021 results - 61.9Mlb of copper and 1.2Mlb of molybdenum.

The company's cash cost guidance for 2022 was US$1.90/lb due, it said, to higher market-driven treatment and refinery charges.

Amerigo also expected an increase in steel prices, which would affect grinding costs - which, along with lower molybdenum by-product credits and the projected escalation of all other costs, would eat into margins.

The company's expected average copper price for 2022 is US$3.90/lb.

The royalty for Codelco's El Teniente was forecasted to be US$1.09/lb.