Rockhaven Resources has announced the results of an updated preliminary economic assessment (PEA) of its 100% owned, road-accessible Klaza deposit in the Dawson Range gold belt of southern Yukon, Canada. Highlights of the PEA include a 12-year mine life producing total payable metals of approximately 750,000 ounces (oz) of gold and 13.8 million oz of silver. Annual payable metal production exceeds 100,000 gold equivalent oz in years three through seven.
Initial capital costs to develop the Klaza deposit are estimated at C$244 million, including C$32 million in contingency costs. Life-of-mine sustaining capital costs total C$114 million.
Average life-of-mine operating cash costs are estimated at $613/gold equivalent oz, and total all-in sustaining costs are estimated at 875/gold equivalent oz.
The Klaza project is envisioned as a combined open-pit and underground mining operation. Open-pit mining is anticipated to be completed by a contract mining company, while the underground operation would be owner-operated. Grid electrical power will provide the majority of the electrical power to the project over the life of the mine. An on-site camp is envisioned to house mine and mill personnel.
Rockhaven President and CEO Matt Turner said, “This study demonstrates that Rockhaven’s Klaza deposit could support a mine with a long life and robust economics. Since the last economic study was completed in 2016, closer-spaced drilling has better defined the upper portions of the deposit, resulting in higher average grades in a superior resource category. We are very pleased with the results of this PEA and look forward to continuing to add value through additional discoveries while advancing the deposit through prefeasibility.”
The proposed Klaza plant flowsheet includes comminution by crushing followed by semiautogenous grinding and ball milling, with the ground product feeding a conventional sequential flotation circuit producing lead, zinc, and arsenopyrite concentrates. The arsenopyrite concentrate is treated by pressure oxidation (POX), followed by cyanide leaching of the POX residue to recover the gold.
Precious metals are also leached from the lead concentrate to increase the overall gold recovery to doré and enhance saleability of the concentrate. Final products from this process are precious-metal-rich lead and zinc concentrates and gold and silver as doré.
The processing plant would operate year-round at a rate of approximately 1,900 metric tons per day (mt/d) and achieve full throughput by year two.
The average life-of-mine feed grade is projected to be 3.4 grams/mt gold, 79 g/mt silver, 0.6% lead, and 0.7% zinc.
