Ann: Initial pit optimisation delivers A$28m NPV for Big One, page-2

ASX/LSE: CCZ 13 July 2023 Exploration with Purpose Initial pit optimisation delivers A$28m NPV for Big One

Highlights

o The preliminary pit optimisation study – completed by Perth-based Entech
Group1 – for the Big One Deposit, which is part of the NWQ Copper Project,
delivered a $28m Net Present Value (NPV)

o Drilling down, the study focused on the near-surface component of known
mineralisation at the Big One Deposit (Mineral Resource Estimate: 2.1Mt @
1.1% Cu for 21,886t copper metal – inferred)2 and provides significant
confidence a standalone mining operation can potentially be developed

o Key findings indicate an initially optimised pit shell could potentially deliver
up to 6,266t copper (head grade: 1.42% Cu), 4,362oz silver (head grade: 0.31
g/t Ag) and 1,469t cobalt (head grade: 0.33% Co)

o As known mineralisation is open south-west and down dip from the pit shell,
there is significant potential to build on the preliminary findings and progress
a mining license once a strategic development partner is secured

o Further, there are over 20 incremental copper, gold, lead, and zinc prospects
across the NWQ Copper Project that are highly prospective for copper
mineralisation which potentially provide the foundations for developing a
series of satellite deposits Castillo Copper’s Chairman Ged Hall commented:

“The Board is delighted with the findings from Entech’s preliminary pit optimisation study, as it provides significant confidence a standalone mining operation can potentially be developed at Big One Deposit.

More importantly, the Board believes the study’s insights will be key to securing a strategic partner
to progress critical development work moving forward.”

PIT OPTIMISATION: A$28M NPV

Castillo Copper Limited’s (“CCZ” Board has received a preliminary pit optimisation study on Big
One Deposit from Entech Group 1 which produced a A$28m NPV (Figure 1). The focus of the study^
was on the near-surface component of known mineralisation based on the Inferred MRE at 2.1Mt @
1.1% Cu for 21,886t 2 copper metal.