MINERAL RESERVES & RESOURCES | MCSA Mining Complex

Mineral Reserve & Resource Notes:

1. Mineral reserve and mineral resource estimates are effectiveas at September 30, 2021.
2. Presented mineral resources inclusive of mineral reserves. All figures have been rounded to the relative accuracy of the estimates. Summed amounts may not add due to rounding.
3. Mineral reserve estimates were prepared in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum (“CIM”) Definition Standards for Mineral Resources and Mineral Reserves, adopted by the CIM Council on May 10, 2014 (the “CIM Standards”), and the CIM Estimation for Mineral Resources and Mineral Reserves Best Practice Guidelines, adopted by CIM Council on November 23, 2003 (the “CIM Guidelines”), using geostatistical and/or classical methods, plus economic and mining parameters appropriate for the deposit. Mineral reserves are based on a long-term copper price of US$2.75 per pound (“lb”), and a USD:BRL foreign exchange rate of 5.23. Mineral reserves are the economic portion of the Measured and Indicated mineral resources. Mining dilution and recovery factors vary for specific mineral reserve sources and are influenced by factors such as deposit type, deposit shape, stope orientation and selected mining method. In the mine design of the Pilar and Vermelhos underground mines, certain stopes include measured and indicated as well as inferred resource blocks. In these instances, inferred resource blocks within the defined mining shape were assigned zero grade. In 2021, inferred blocks assigned zero grade totaled approximately 159,000 tonnes for the Deepening Extension Zone, 296,500 tonnes for the Pilar Underground Mine and approximately 80,000 tonnes for the Vermelhos Underground Mine. Development occurring within marginal ore, above the operational cut-off grade, has also been included in the mineral reserve estimate. Dilution occurring from measured and indicated resource blocks was assigned grade based upon the mineral resource grade of the blocks included in the dilution envelope.
4. Underground mineral resource estimates have been constrained within newly developed 3D lithology models applying a 0.45% and 0.20% copper grade envelope for high and marginal grade, respectively. Within these envelopes, mineral resources for underground deposits were constrained using varying stope dimensions of up to 20m by 10m by 35m applying a 0.51% copper cut-off grade, as well as a 0.32% copper marginal (or operational) cut-off grade. Mineral resources have been estimated using ordinary kriging inside 5m by 5m by 5m block sizes. The mineral resource estimates were prepared in accordance with the CIM Standards, and the CIM Guidelines, using geostatistical and/or classical methods, plus economic and mining parameters appropriate to the deposit.
5. Open pit mineral resources have been constrained within newly developed 3D lithology models using a 0.21% copper cut-off grade for deposits. Mineral resources have been estimated using ordinary kriging inside 5m by 5m by 5m block sizes. The mineral resource estimates were prepared in accordance with the CIM Standards, and the CIM Guidelines, using geostatistical and/or classical methods, plus economic and mining parameters appropriate to the deposit. 

Mineral resources which are not mineral reserves do not have demonstrated economic viability.