Pinnacle Silver and Gold reports strong gold recovery results for El Potrero project
Tue June 02 2026
Pinnacle Silver & Gold Corp has released results from a second phase of scoping metallurgical testing at its El Potrero gold-silver project in Durango, Mexico, highlighting consistently high gold recoveries and improved silver recoveries across multiple vein systems.
The latest testing expanded on an initial program by evaluating seven mineralized samples from the Dos de Mayo, Estrella and Capulin veins, compared with three samples tested previously. The program included material from all three historic mines along the Dos de Mayo vein system. Bottle roll cyanide leach tests returned average gold recoveries of 97.83% for a composite sample from the Dos de Mayo vein. Gold recoveries from the Estrella and Capulin veins were 97.6% and 97.4%, respectively.
Silver recoveries were more variable, reflecting what the company described as more complex silver mineralization. The Dos de Mayo composite achieved a silver recovery of 70.02%, while recoveries from the Estrella and Capulin veins were 64.7% and 80.5%, respectively.
Head assays from the seven samples averaged 7.7 grams per tonne (g/t) gold and 116 g/t silver.
The company also completed TIMA-X mineralogical analyses on sub-samples. The studies identified gold in the form of electrum, a naturally occurring gold-silver alloy, in all seven samples. Silver-bearing minerals, including argentite/acanthite and aguilarite, were also detected.
According to the analyses, gold grains were consistently smaller than 50 microns and silver particles were less than 80 microns in size, providing guidance for processing and grinding requirements. Five samples from the Dos de Mayo vein were combined into a composite and subjected to grinding, gravity concentration and leaching tests. Grinding calibration work achieved a target grind size of 80% passing 270 mesh, with a Bond Work Index of 18.1 kilowatt-hours per tonne, which the company described as average.
Tests showed that direct cyanide leaching produced the strongest overall metallurgical performance. A composite sample ground to 53 microns achieved gold and silver recoveries of 97.83% and 70.02%, respectively. When ground to 75 microns, recoveries were 96.79% for gold and 66.38% for silver. Gravity concentration followed by leaching did not improve recoveries. According to SGS, which conducted the testing, the gravity circuit slightly reduced overall gold recovery and resulted in a more pronounced decrease in silver recovery compared with direct leaching alone.
SGS concluded that the ore demonstrated an "excellent response to cyanidation," particularly for gold extraction, and that direct leaching delivered the best overall metallurgical results.
Average reagent consumption remained within expected ranges for preliminary testing. Sodium cyanide consumption ranged from 0.79 kilograms per tonne to 1.46 kilograms per tonne, while lime consumption ranged from 0.60 kilograms per tonne to 0.70 kilograms per tonne.
Pinnacle CEO Robert Archer wrote that the expanded testing program demonstrated robust grades, improved recoveries and consistently strong gold extraction across the project's three principal veins. He added that the work was conducted using baseline parameters with limited optimization and that further improvements may be possible through additional testing.
“Overall, these results are providing valuable information as we streamline the flow sheet prior to rebuilding the plant,” Archer said. Pinnacle said ongoing metallurgical work is focused on solid-liquid separation studies to support dry-stack tailings storage and water recycling plans for a future processing facility.
Source: https://www.proactiveinvestors.com/