Fitzroy Minerals Inc. (TSXV: FTZ, OTCQX: FTZFF, FSE: C3Y) has reported results from the initial phase of metallurgical test work at its Buen Retiro Copper Project near Copiapo, Chile, showing copper recoveries of up to 82.6% from mini-column testing, with preliminary larger-scale results trending higher. The announcement, made via NEWMEDIAWIRE, comes as the company advances its planned heap-leach development plan for the project.
The test program, conducted by SGS Laboratories, evaluated the response of three principal geometallurgical units—high-grade oxide, low-grade oxide, and mixed—to heap leaching. Mini-column testing, the first stage of column-based testing, is complete, while larger 1-metre column tests are ongoing and already trending above mini-column results. Total copper recovery after 21 days reached 71.8% for high-grade oxide, 59.9% for low-grade oxide, and 82.6% for mixed material, with low-to-moderate net acid consumption ranging from 3.4 to 11.2 kg/kg.
Preliminary 1-metre column results point to further improvement as leach time and scale increase. Projections indicate recoveries after 70 days of approximately 95% for mixed material, 85% for high-grade oxide, and 74% for low-grade oxide. These figures would typically be multiplied by a scaling factor of 0.8 to 0.9 to estimate industrial copper recovery. The company also noted favourable rock hardness, with Bond Work Indices below 8 kWh/t, indicating soft, easily-crushed material, and medium-to-moderate abrasiveness.
Merlin Marr-Johnson, President and CEO of Fitzroy, commented that the results exceed expectations. “Final copper recoveries of up to 82.6%, achieved with low acid consumption and excellent reproducibility across three separate Units in just 21 days, give us real confidence in the heap-leach case for the Project,” he said. “Even more encouraging is that the more representative, one-metre columns are trending higher, pointing towards a final recovery of 95% after 75 days of leaching, for the Mixed material. Combined with soft, easily-crushed, moderately abrasive rock, this test work materially de-risks our path toward heap-leach production at Buen Retiro.”
The test program is staged, with 208 separate tests planned on 3,341 kg of samples. Ten mini-column tests were completed, along with hardness and abrasivity testing and mineralogical analysis. The mini-column campaign has a closed metallurgical balance, with head grades of 0.95% CuT for high-grade oxide, 0.35% for low-grade oxide, and 1.24% for mixed material. Duplicate tests confirmed good reproducibility, with copper extractions within 1 percentage point of each other, as shown in Table 2: Duplicate results of CuT extraction at 21 days of leaching, mini columns (closed).
Recovery kinetics for all three units show two distinct stages: an initial fast-leaching stage associated with more soluble oxidized copper species, followed by a slower stage attributable to more refractory species. Because recovery curves were still trending upward at 21 days, the company expects further gains from extending leach time, as is already being tested in the 1-metre columns. The addition of chloride during agglomeration and leaching improved copper recoveries by 3 to 5 percentage points in both oxide units, at similar acid consumption, and has been identified as an opportunity to optimize the flowsheet.
For the mixed unit, increasing the agglomeration acid dose raised recovery by 2 to 4.5 percentage points, while raising leach chloride concentration improved extraction by a further 3 percentage points. Preliminary results from the 1-metre columns, after 68 days for oxides and 53 days for mixed material, show copper recoveries trending toward 85% for high-grade oxide, 74% for low-grade oxide, and approximately 95% for mixed material. These preliminary results are shown in Figure 2. Copper recovery of Chloride Leach Samples after 68 and 53 days (trends projected to 75 days), head analysis.
The company expects to finalize the 1-metre column metallurgical balances by the end of September 2026, complete the full 1-metre column campaign by mid-December 2026, and begin 3-metre column testing in November 2026. A final metallurgical report is expected by March 1, 2027, with results to be incorporated into a Pre-Feasibility Study planned for release in Q2 2027. The original release can be viewed at www.newmediawire.com.
