Published On: August 17th, 2023


Metallurgical studies were conducted for both Ranch and Lawyers to characterize the processing potential separately from each project. Composite samples were selected to best represent the geological and geochemical conditions of the resource material at Lawyers and the anticipated resource material at Ranch. The following provides an overview of metallurgical results from each testing program. Further details of the Lawyers metallurgical study are provided in the Preliminary Economic Assessment (PEA).

Metallurgical studies for the Lawyers Project were advanced and coordinated by F. Wright Consulting Inc., under the direction of Frank Wright, P. Eng., an independent metallurgical consultant with extensive experience in precious and base metal process development. He is a qualified person as defined by National Instrument 43-101. The supporting studies were conducted by globally recognized laboratories, including ALS Laboratory, BV Mineral Process Laboratories, FLSmidth Inc., and SGS Mineral Services.

A more extensive metallurgical testing program is scheduled to begin in October 2023 to support an updated PEA encompassing the advancement of a processing flowsheet that considers material from both the Ranch and Lawyers projects.

Metallurgical Overview – Lawyers Gold-Silver Project

This overview is a summary derived from the Preliminary Economic Assessment (PEA) of September 2022.

Preliminary Testing

The preliminary metallurgical testing for the Lawyers Project, focused on a bulk tonnage open pit mining scenario, commenced in Spring 2020 and concluded in mid-2021. Prior to 2020, there is limited historical information relevant to this type of operating scenario. The testing during 2020/2021 encompassed both flotation and cyanide leaching; The Lawyers material responded well to both processes. Based on the results and economic considerations, the PEA flowsheet design was directed towards whole rock cyanide leaching.


Leaching would be facilitated in aerated tanks after a gravity pre-treatment to remove coarser precious metal particles. The mined rock is categorized as moderately hard to hard. Optimization laboratory testing suggests a feed particle size to the leach at a modest grind, with 80% passing particle size (P80) of 106 µm. The laboratory data indicates a tank leach retention time of 32 hours or less. The pregnant leachate solution (PLS) would undergo washing by counter current decantation (CCD) and then proceed to zinc precipitation to produce Doré on site.

Recovery Rates

The PEA level testing was conducted on composite samples from Cliff Creek (including Dukes Ridge) and AGB zones. Gold leach dissolution recoveries consistently ranged from 91% to 97% on head grades of 0.46 g/t to 3.04 g/t. Silver recovery, influenced by changes in mineralogy related to electrum particle size and composition, varied more, showing a 50% to 92% leach dissolution recovery on composite samples with a head grade range of 3.8 g/t to 165 g/t. The average precious metal design recovery for the AGB Zone is 92.1% for gold and 60.6% for silver. For the Cliff Creek Zone, the average gold recovery is 92.5%, and for silver, it’s 83.0%.

For a more detailed understanding and additional information, please refer to the Preliminary Economic Assessment – September 2022.

Metallurgical Overview – Ranch Project

The studies focused on samples from the Bonanza, Ridge, Thesis II, and Thesis III zones, chosen based on geological, core logging, and geochemical criteria to best represent a potential resource. The majority of testing was conducted at Bureau Veritas Minerals in Richmond, BC. Tests have shown all samples responded well, achieving between 90% to 98% gold recovery.


Flotation testing has shown a positive response, especially for samples with elevated copper and silver content. The primary float product produced a cleaned concentrate grade exceeding 22% Cu, with additional gold and silver credits. Gold recovery from flotation for the tested composites ranged between 90% to 98.9%. The work to date indicates a moderate grind with a particle size of approximately 80% passing (P80) of 74 microns or coarser is sufficient for the float feed.


Leaching tests have shown varying results based on the sulphide content and other mineralogical factors. Notably, samples with less than 1% sulfur (S) demonstrated gold leach dissolution recovery exceeding 90%. This recovery rate decreased as the sulfur content increased. The findings suggest that while the Ranch mineralized zones with lower sulfur content is highly amenable to leaching, ores with elevated sulfur content might benefit from flotation.

For more detailed information, please refer to the News Release from October 12, 2022.

Exploration in the Toodoggone Mining District began in the 1960s by prospectors drawn to the area by prominent rusty colored ridges and waterways. By the 1980s, numerous precious metal occurrences, prospects, and deposits were defined and discovered including porphyry gold-copper mineralization at Kemess, and epithermal style mineralization at Ranch and Lawyers.