Granite Creek Copper Receives Preliminary Metallurgical Results Demonstrating Potential for Significant Additional Copper Recovery

VANCOUVER, BC / ACCESSWIRE / August 23, 2023 / Granite Creek Copper Ltd. (TSX.V:GCX)(OTCQB:GCXXF) ("Granite Creek" or the "Company") is pleased to announce the preliminary results of a metallurgical study designed to increase recovery of copper from oxide material at its Carmacks Copper-Gold-Silver project ("Carmacks Project" or the "Project")

Kemetco Research Inc. ("Kemetco") has been contracted to carry out an initial series of scoping tests to evaluate the potential for extraction and recovery of copper from unrecovered copper oxide minerals in Carmacks Project flotation tailings as referenced in the Company's 2023 Preliminary Economic Assessment ("2023 PEA") ^*. Testing involves the leaching of tailings from previous flotation testing of oxidised copper material to dissolve copper into solution and subsequently precipitate copper in a form that could be added to a concentrate being produced by sulphide flotation. The leaching portion of the test work has now been completed with up to 81% of the copper present in the test samples going into solution. The remaining project task, currently underway at Kemetco, is to complete a series of bench tests to evaluate methods for selective recovery of the leached copper from solution. The planned tests will focus on copper sulphide precipitation to target generation of a high-grade copper sulphide product that could potentially be combined with a copper flotation concentrate in an overall production flowsheet, resulting in significant potential increases to both overall copper recovery and the copper grade of the final concentrate product.

The 2023 PEA was based on an average recovery of copper, life of mine ("LOM") of 64%, with up to 93.7% recovery of copper when processing sulfide material but only 39.8% when processing oxide material. The current mine plan as outlined in the 2023 PEA contemplates processing material with a high oxide content of up to 80% oxide ore in the first five years of the mine life during which time over 8.4 million tonnes of oxide material would be processed versus 2.88 million tonnes of sulphide material. Sensitivity analysis completed in the 2023 PEA identified over $180M of Net Present Value ("NPV") to be gained from a combined sulphide-oxide recovery system by increasing the LOM recovery of copper by 20% from the current projected 64% to 77% total copper recovery.