Updated NI 43-101 for Marimaca Copper Project

The Preliminary Economic Assessment ("PEA") was prepared in accordance with the requirements of the National Instrument 43-101,Standards of Disclosure for Mineral Projects ("NI43-101") (refer release on 4 August 2020) and is based on a Mineral Resource Estimate ("MRE") completed by NCL, which comprised 70 million tonnes, with an average grade of 0.60% total copper within the Measured & Indicated Categories of mineral resources (approximately 420Kt of contained copper),and 40 million tonnes with an average grade of 0.52% total copper within the Inferred Category of mineral resources(approximately 224kt of contained copper) (refer release on 2 December 2019). The PEA is considered preliminary in nature and includes Inferred Mineral Resources that are considered too speculative, geologically, to have the economic considerations applied that would enable classification as Mineral Reserves. There is no certainty that the conclusions within the PEA will be realized. The PEA is based on the material assumptions outlined in the PEA and summarized in the press release on 4 August 2020. These include assumptions about the availability of funding. While the Company considers all of the material assumptions to be based on reasonable grounds, there is no certainty that they will prove to be correct or that the range of outcomes indicated by the PEA can be achieved.

VANCOUVER, British Columbia, Sept. 21, 2020 (GLOBE NEWSWIRE) -- Marimaca Copper Corp. ("Marimaca Copper" or the "Company") (TSX: MARI) is pleased to announce the filing, on SEDAR, of an updated National Instrument 43-101 ? Standards of Disclosure for Mineral Projects ("NI 43-101") Technical Report dated September 18, 2020, for the Company's flagship Marimaca Copper Project ("Marimaca" or "the Project"), located in northern Chile.

Exceptional PEA Results for the Marimaca Project including US$524 million post-tax real NPV8 and 33.5% IRR

Highlights from the PEA Results

• US$524 million post-tax NPV₈ (real) assuming a US$3.15/lb flat long-term copper price
  • Payback of 2.6 years
  • Post-tax IRR of 33.5%
• US$640 million post-tax NPV₈ (real) assuming a US$3.45/lb flat long-term copper price
  • Payback of 2.4 years
  • Post-tax IRR of 38.0%
• Average annual steady state EBITDA of US$169 million
• Pre-production capital cost of US$285 million
  • Capital intensity of US$7,125/tonne of copper production capacity
  • Assumes mining fleet is purchased via lease to own to minimize upfront capital costs
• Profitability Index (NPV/Capex) of 1.8x
• Life of mine average all-in-sustaining cash costs of US$1.29/lb of copper¹
  • Life of mine average C1 Cash Costs of US$1.22/lb of copper²
• Conventional open pit mining focused exclusively on oxide mineralization
  • Life of mine stripping ratio of 0.84:1
  • Highest grade feed materials available in first five years of production resulting in improved payback and overall economics
• Conventional heap leach, SX-EW, processing circuit
  • Projected average life of mine metallurgical recoveries in heap leach of approximately 76% of total copper supported by data from several metallurgical testing programs
  • Process makes use of readily available sea water
• Average annual steady state copper production over first 6 yrs of close to 40,000 tonnes of cathode
  • Total mine life of 12 years
  • Total recovered copper of approximately 430,000 tonnes over the life of mine
• Significant ongoing exploration potential for both oxide and sulphide mineralization which could substantially extend the mine life of the Project

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¹ All in sustaining costs is defined as cash cost (C1) plus general and administrative expenses, sustaining capital expenditure, deferred stripping, royalties and lease payments and is used by management to evaluate performance inclusive of sustaining expenditure required to maintain current production levels.
² C1 cash cost includes all mining and processing costs less any profits from by-products and is used by management to arrive at an approximated cost of finished metal.

For further details, and to read the full PEA results for the Marimaca Copper Project, please refer to the announcement released August 4, 2020, which can be accessed via Marimaca's website.

Contact Information
For further information please visit www.marimaca.com or contact:

Tavistock
+44 (0) 207 920 3150
Jos Simson/Emily Moss
[email protected]

Notes to Editors
Marimaca is fast becoming recognised as one of the most significant copper discoveries in Chile in recent years as it represents a new type of deposit which challenges accepted exploration wisdom and promises to open up new frontiers for discoveries elsewhere in the country. Marimaca is hosted by intrusive rocks while the numerous manto deposits in the same region are hosted by volcanics. With a lack of new copper exploration discoveries in Chile, the growing Marimaca resource is a high-profile development project as it is situated in the coastal belt at low elevation close to Antofagasta and Mejillones. This prime location could enable its future development at a relatively modest capital investment. Marimaca will benefit from nearby existing infrastructure including roads, powerlines, ports, a sulphuric acid plant, a skilled workforce and seawater.