Mined Grade Trends over 2005 - 2022

Data extracted from AME’s global mine database reveals that between 2005 and 2022, the average grade of copper ore mined declined from 0.75% to 0.54%. This represents a 1.6% CAGR decline. Sulphide ore extracted from open-pit mines and processed to concentrate accounts for an estimated 61% of total ore mined in 2022.

The average mined grade of this ore has fallen from 0.78% in 2005 to 0.54% in 2022, a 2.2% CAGR decline. Oxide ore mined from open pits is of lower copper grade overall averaging 0.44% in 2022, a 0.8% CAGR decline. This type of ore accounts for an estimated 27% of total ore mined in 2022.

Grades of sulphide ore mined from underground are substantially higher than open-pit copper ores, but make up a small proportion of total ore mined. Average underground sulphide ore grade declined at a CAGR of 1.7% from 1.39% copper in 2005 to 1.04% in 2022.

In 2022, AME estimates underground sulphide ore made up 12% of the total copper ore mined. The average grade of this ore type increased during 2019 to 2022 as large higher-grade underground mines, including Kamoa-Kakula (with initial copper grades of around 6%) in the DRC, Timok (~6% Cu) in Serbia, Khoemacau (~2% Cu) in Botswana, Carrapateena (~1.4% Cu) in Australia and Carajas (~1.7%) in Brazil, were developed and started operations.

The declining grade trends are due to declining copper grades at some of the world’s largest copper mines and the development in recent years of low-grade deposits.

BHP’s 1.1Mtpa Escondida, Freeport’s 500ktpa Cerro Verde, Codelco’s 450ktpa El Teniente, Antofagasta’s 400ktpa Los Pelambres, and Anglo American’s 300ktpa Los Bronces each display declining copper grade trends in recent years.

Copper mines that started production in recent years and are mining ore with grades less than or equal to 0.56% copper, and therefore contributing to a decline in average grades, include First Quantum’s 400ktpa Cobre Panama and Russian Copper’s 150ktpa Tominsky GOK. These two mines extract ore with only 0.4% copper.

Country Level Mined Grade Trends

AME’s global mine database permits grade trends to be broken down by country.

The top two producing countries are Chile and Peru in South America. Copper grades for both countries are close to the global average but are declining faster than the industry overall. AME estimates average grades of ore mined in 2022 were 0.62% in Chile and 0.47% in Peru, and that the CAGR declines since 2005 are 2.2% and 3.2%, respectively. As mentioned above, the comparative global figures are 0.57% copper and a -1.6% CAGR. 

Mines in the United States, Canada and Mexico extract lower grade ore than the industry average, due to the relatively low copper content of North American porphyry deposits. Estimated 2022 average grades of ore mined are 0.33% for the US, 0.32% for Canada and 0.28% for Mexico.

The mines in the DRC and Zambia exploit African Copperbelt sediment hosted deposits that are characterised by higher grade ores. The DRC’s average copper grade increased in the past five years from 2.53% in 2018 to 3.31% in 2017, largely due to the ramping up of Ivanhoe and Zijin’s large, high-grade Kamoa-Kakula underground mine that after three-phased expansions will produce over 600ktpa of copper in concentrate from 19.2Mtpa of ore grading over 5.0% during its first ten years.

The DRC is not included on the accompanying chart because the grades are so much higher. Average grade in Zambia in 2022 is estimated to be 0.73% copper, down from above 1.0% before 2015. This significant drop is largely due to the start-up of First Quantum’s large, low-grade Sentinel open-pit mine in 2015. The mine extracts around 60Mtpa of ore grading less than 0.5% copper in recent years.

Poland’s mine production of 400ktpa of copper is also high grade. KGHM’s Rudna, Lubin and Polkowice-Sieroszowice underground mines extract ore averaging 1.48% copper from extensive sediment hosted deposits in southwest Poland.

Mined copper grades in Australia are higher than the global average, estimated at 0.64% in 2022. Australian mines exploit a mix of deposit styles including high-grade sediment hosted hydrothermal (e.g. Glencore’s 100ktpa Mount Isa at 2.08% copper and 50ktpa Cobar at 3.95% copper) and volcanic hosted massive sulphide (e.g. Sandfire’s 65ktpa DeGrussa at 4.72% copper) deposits, moderate to high grade iron oxide copper-gold deposits (e.g. BHP’s 180ktpa Olympic Dam at 2.16% copper, OZ Minerals’ 60ktpa Prominent Hill at 1.42% copper and 60ktpa Carrapateena at 1.32% copper, and Evolution’s 65ktpa Ernest Henry at 1.07% copper), and low to moderate grade porphyry deposits (e.g. China Molybdenum’s 50ktpa Northparkes at 0.60% copper).