Ero Copper announces major new discovery – West Limb of the Pilar Mine

Ero Copper announces major new discovery – West Limb of the Pilar Mine

Ero Copper Corp. (the “Company”) (TSX: ERO) is pleased to announce a major discovery of a new parallel zone of copper mineralization within the Pilar underground mine, on its 99.6% owned Vale de Curaçá Property located in Bahia State, Brazil.

The new discovery, the “West Limb”, is a mineralized intrusive body of mafic-ultramafic rocks that extends parallel to the existing underground workings of the Pilar Mine, which over the past 37+ years, has predominately mined a structure now referred to as the “East Limb”. The discovery of the West Limb is based on the culmination of more than a year of historic geological and drill hole data compilation, structural modelling of known mineral resources as well as new confirmatory drill testing undertaken by the Company to verify continuity. The combination of historic drill results and new drilling above the P1P2W planned mining area within the West Limb have delineated a mineralized zone that stretches over a north-south strike length of approximately 1,300 meters and to a depth of approximately 500 meters. The zone remains open to depth. Additional infill drilling is currently being planned to verify historic drill results and to drill untested areas within its strike-length.

The potential significance of the new West Limb discovery includes the following:

Copper mineralization is delineated in a series of mineralized lenses that form a parallel structure on average approximately 200 meters to the west of existing Pilar underground mine infrastructure;
Includes the current P1P2W mineral reserve and resource, scheduled for first production during the second half of 2018 – previously thought to be an isolated zone west of the main Pilar Mine; and,
Mineralization is adjacent and parallel to the mine’s existing infrastructure, including ramp, horizontal development, power, water, ore passes and underground crushing facilities.
The historic drill database is comprised of 61 drill holes, of which 32 drill holes totaling 9,050 meters of drilling, have been verified under the Company’s quality assurance and quality control (“QA/QC”) programs and are expected to be incorporated into the Company’s mid-year National Instrument 43-101 (“NI 43-101”) mineral resource and reserve update, expected to be released during the third quarter of 2018. The balance of the historic drill data is currently being reviewed for inclusion in subsequent updates through a certification program which will include re-sampling and twin-hole drilling as required.

Figures 1 and 2 provide north-south long section and plan views, respectively, of the West Limb including both historic and recent drilling as well as the P1P2W mining area. These parameters currently serve to outline the known extent of mineralization of the West Limb.

The Company currently has 3 exploration drill rigs operating in the P1P2W mining block and is developing a program to move these rigs, and other rigs currently operating in Pilar, from definition drilling to delineating the extent of the new discovery with a focus on developing the first NI 43-101 compliant mineral resource and reserve estimate of the West Limb. Additionally, exploration drilling will be conducted down-dip of the identified mineralization to evaluate whether the West Limb continues to parallel the East Limb at depth. The primary ramp of the Pilar underground mine has been completed to level -843, approximately 1,300 meters below surface, following the mineralization of the East Limb.

The various sets of data that have been evaluated to form the basis of the West Limb discovery are as follows:

HISTORICAL DRILL DATABASE

The Company’s geological team, over the past 14 months, has been compiling all historical drilling completed at the Pilar Mine. Initially this process focused on identifying, compiling and verifying priority data that was used, in part, to form the basis of the Pilar Mine’s current NI 43-101 mineral resource and reserve estimate as outlined in the 2017 Technical Report (as defined below). Following the completion of the 2017 Technical Report, the team began to analyze the remaining drill results, previously not included in the 2017 Technical Report, in order to model structural controls on copper distribution in the mine. During this process, it was observed that a significant concentration of copper mineralization was prevalent west of the existing mine infrastructure. In total, 61 drill holes within the drill database were identified as having intersected the West Limb and to date 32 of the holes have been verified under the Company’s QA/QC program and are shown in the table below:

Hole ID From (m) To (m) Interval (m) Cu (%)
FC3769 46.0 69.0 23.0 1.33
FC3870 18.1 26.1 7.9 0.95
FC3876 7.0 17.1 10.1 2.47
and 27.1 30.0 2.9 2.39
FC3881 14.0 26.1 12.0 1.48
FC3893 31.1 44.0 13.0 1.19
FC39111 3.1 15.1 12.0 2.36
and 24.1 35.1 11.0 2.64
and 48.0 66.1 18.1 1.07
FC4097 4.1 26.1 22.0 0.84
FC40122 48.3 54.1 5.8 2.59
and 62.3 70.7 8.4 1.48
FC41148 491.0 497.6 6.6 1.16
and 504.9 525.0 20.1 2.12
FC42118 36.1 41.2 5.0 3.08
and 62.0 71.0 9.0 1.79
and 81.1 91.1 10.1 1.40
FC42121 – 23.0 23.0 2.77
including 6.1 12.0 5.9 3.75
and 52.1 56.1 4.0 2.41
FC42144 334.1 342.1 8.1 1.51
FC4349 40.1 49.1 9.0 1.96
and 57.2 60.2 3.1 5.88
and 66.1 75.1 9.0 1.93
including 68.1 70.1 2.0 5.63
FC4350 51.1 62.0 11.0 3.40
and 80.0 88.1 8.1 0.93
and 96.0 104.1 8.1 1.14