Sierra Metals Inc. after systematic drilling in 2023, announced additional 15.5 million copper equivalent pounds in measured and indicated mineral resources hosted by the Dulce structure at its Bolivar mine in Mexico. The results reported include 52 drill holes from a total of 91 holes in the 2023 drill program, which increases the mineral resources when compared to those reported in the 2021 preliminary economic assessment ("PEA"). By including these new bore holes in the evaluation, the dimensions of the mineralized ore body are now extended by approximately an additional 400m, along strike by 300m vertically.

The recent results in the enlarged mineralized zone, now has higher copper ("Cu") and gold ("Au") grades in comparison to average grades published in 2022 (833,058 tonnes @ 0.74 % Cu, 0.36 grams per tonne ("g/t") Au, 26.03 g/t silver ("Ag"). Additional drilling is planned for the coming months. The mineralized body or "feeder zone" called Dulce strikes in a northeast - southwest trend with a 60° dip to the northwest.

Its vertical projection extends from surface downwards until connecting with the mantos Bolivar NW and Cieneguita. Spatially, the Dulce zone is located between the mentioned manto bodies Bolivar NW and Cieneguita, cutting carbonate rocks previously affected by calc-silicate metasomatism. The width of mineralization varies between 0.50m and 57.30m, with the best skarn development occurring at the contact with the mantos.

Copper and gold grades are directly correlated to the presence of chalcopyrite, lesser bornite, and pyrite. In addition, significant amounts of sphalerite and minor galena are present.