Integra Resources (ITR.V, ITRG) is keeping up the pace of its stockpile and backfill drill program. The company has already completed almost 4,000 meters in 86 holes (which confirms the very shallow nature of the rock that could potentially be added to the heap leach scenario as the average depth is less than 50 meters).
The grades and widths encountered in the program so far are either meeting or even exceeding the expectations and every hole further validates the potential to actually process these historical stockpiles. The majority of the rock encountered in t he drill program consists of primary oxide with some mixed material as well. Just to be sure the material is amenable to be used in a heap leach process, Integra is conducting additional metallurgical test work. Hot cyanide shakes are being performed and so far, the initial results confirm the bottle roll tests and column test results completed on the oxide mineralization in the planned open pit and the recovery rate for the gold exceeds 70%. This means that even the 0.23 g/t material would have a recoverable value of almost US$10/t using a gold price of $1800/oz and a recovery rate in the lower 70% range.
Due to the success of the initial drill program (hitting gold and silver values exceeding the cutoff grades required for a heap leach operation throughout the drill program) a third rig was added to the drill program. Two sonic drill rigs and one Reverse Circulation rig are now drilling the high priority targets at 60 meter collar spacings with 30 meter infill test holes.
Integra has an exploration target of 60 million tonnes and even if it would only define 40 million tonnes at 0.27 g/t gold (not equivalent, but gold), about 350,000 ounces of gold could be added to the mine plan. And assuming a recovery rate of 72%, about 250,000 additional ounces of gold could be recovered on top of what was included in the pre-feasibility. And although the silver doesn’t leach well, an average recovery rate of 35% applied to 15 g/t material would still generate about US$4/t in by-product revenue which would pretty much cover the entire processing cost (estimated at US$3.80 per tonne in the 2022 pre-feasibility study).
Disclosure: The author has a long position in Integra Resources. Integra is a sponsor of the website. Please read our disclaimer.
