The Feasibility Study contemplates open pit mining from the Dark Star and Pinion deposits. The mine is designed as a traditional truck and shovel operation with one year of pre-production and eight years of subsequent mining. Ore will be sent run-of-mine (“ROM”) to a leach pad to be processed.
A total of 29.2 million tonnes of ROM ore is scheduled to be mined from the Dark Star pit averaging 0.90 g Au/t, mined at a relatively steady rate over the first six years of operation. Mining from the Pinion pit is projected to produce a total of 36.0 million tonnes of ROM ore at an average grade of 0.66 g/t Au and 5.3 g/t Ag. The ROM ore deliveries from the two pits total 65.2 million tonnes at an average grade of 0.77 g Au/t.
The open pits have been designed and scheduled to maximize project rate of return. Life of mine (“LOM”) strip ratios will be 2.80 at Dark Star and 5.15 at Pinio and mining will be by conventional drill / blast / load / haul methods on 9.1-meter benches.
The process selected for recovery of gold and silver from the Pinion and Dark Star ore is a conventional ROM heap leach. Pinion and Dark Star ore will be truck-stacked on the heap as ROM ore directly, without crushing. ROM ore will be stacked in accordance with the mine plan, which averages 8.0 million tonnes of ore per annum, with a peak of 10.8 million tonnes of ore in Year 5. The ROM ore placement is equivalent to a LOM average of 24,700 tonnes per day. ROM heap leach head grade versus gold recovery models were developed for Dark Star and Pinion and silver recovery models were developed for Pinion. Silver grades for Dark Star were not of economic significance. The overall LOM average gold recovery for the Dark Star deposit is estimated at 72% and the Pinion deposit is estimated at 56%.
The Feasibility Study Technical Report was prepared by M3 Engineering & Technology Corporation (“M3”) with support from other consultants including Fort Lowell Consulting PLLC, MDA (a division of RESPEC), GL Simmons Consulting, LLC, New Fields, and EM Strategies, Inc.
|South Railroad Feasibility Study Highlights||Units||Values|
|Throughput Rate per Day||tonnes||24,700|
|Total Ore to Leach Pad||M tonnes||71.9|
|Gold Grade (Average)||g/t||0.77|
|Silver Grade (Average)||g/t||5.30|
|Average Gold Recovery||%||64.5%|
|Average Silver Recovery||%||10.8%|
|Average Annual Gold Production||ounces||124,000|
|Strip Ratio ||waste : ore||4.1|
|Initial Capex||US$ million||$190|
|Avg. Life of Mine Operating costs||$/t ore processed||$11.23|
|Total Cash Cost (net of by-product credits)1 ||$/oz Au||$792|
|All-In Sustaining Cost (“AISC”)1||$/oz Au||$1,021|
|Pre -Tax - NPV (5% discount rate)||US$ million||$389|
|After-Tax - NPV (5% discount rate)||US$ million||$315|
1. Total cash cost and AISC are non-GAAP measures and are net of silver credits and includes royalties payable. See Notes in Appendices regarding non-GAAP measures.