Plutonic Gold Belt: depth extensions at Old Highway and Cinnamon point toward a longer mine life
Catalyst Metals produced 26,127 ounces from the Plutonic Gold Belt in the March quarter, bringing its year-to-date total to 71,875 oz on track for 100,000–110,000 oz guidance. Five mines feed a single 2 Mtpa carbon-in-leach processing plant. The company holds A$277 million in cash and bullion with no debt, A$100 million in undrawn facilities, and a strategic target: double production to 200,000 oz per annum from up to six ore sources over a ten-year mine life.
Two sets of drill results released in the quarterly report show where that growth is being built.
The result at Old Highway: depth extension into Zone 400
Old Highway sits 40 km south of the central Plutonic processing hub. It already underpins a 140,000 oz reserve at 3.2 g/t Au, supporting a planned 35,000 oz per annum open pit and underground operation with a four-year mine life. Development is expected to begin in CY2027.
The new intercepts come from Zone 400, approximately 300m below the existing resource. The standout results include 26m at 5.9 g/t Au, 8m at 10.5 g/t Au, 22m at 3.1 g/t Au, and 21m at 3.2 g/t Au. The widths and grades at this depth are consistent with the upper portions of the deposit, suggesting that the mineralised system continues with coherent geometry well below the current mine plan.
For a deposit already permitted and heading into development, deep extensions at these grades carry a specific commercial implication: the four-year mine life may understate what Old Highway ultimately delivers. Each additional year of underground feed at 35,000 oz pa materially changes the return profile of the development decision.
Cinnamon: a potential sixth ore source
Separately, drilling beneath the Cinnamon open pit resource, located approximately 25 km from the processing plant via haul road, has delineated a new high-grade zone that remains open along strike and at depth.
The results are substantial: 33m at 7.4 g/t Au, 22m at 14.3 g/t Au, 37m at 4.2 g/t Au, and 18m at 9.7 g/t Au. These widths and grades sit well above the existing Cinnamon open pit resource of 3.0 Mt at 1.5 g/t Au for 145,000 oz. The new zone beneath it is a different proposition.
Cinnamon is not yet included in the growth strategy. If the zone proves continuous enough to support an underground operation, it would become the sixth ore source feeding the Plutonic plant, adding mine life without requiring new processing infrastructure.
The Plutonic architecture: why it matters
The Plutonic Gold Belt hosts a 4.2 Moz mineral resource at 3.2 g/t Au across multiple deposits. The operational model is a central processing hub fed by satellite mines at staggered development stages: Plutonic Main underground (85 koz pa), Trident (60 koz pa, transitioning from open pit to underground), K2 (20 koz pa, ramp-up expected June quarter 2026), Old Highway (35 koz pa, development CY2027), and potentially Cinnamon.
This architecture means each discovery extends the mine life without new capital-intensive processing infrastructure. The drill bit adds years; the plant absorbs them. For a company with A$377 million in available liquidity and no debt, the capacity to fund exploration and development simultaneously from operating cash flow gives the growth trajectory a durability that speculative-stage explorers cannot replicate.
What this means for the workforce
A belt operation developing two new underground mines while exploring a sixth ore source requires sustained geological staffing across multiple active sites simultaneously. Core logging, structural interpretation, resource definition drilling and grade control all run in parallel across Plutonic Main, Trident, K2, Old Highway and Cinnamon.
At Norwest Exploration and Mining Services, we specialise in rapid deployment of geologists and field technicians into active programmes across Australia. Operations at this scale need experienced people across every site, not just the flagship. When multiple mines ramp up in the same belt within twelve months of each other, field team capacity is the constraint that determines whether the growth timeline holds.
The processing plant defines the throughput. The drill results beneath it define how long it runs.