Apollo Silver Corp. reported results for barite flotation test work and quality analysis, completed as part of its 2022 Metallurgical Test Program (the “2022 Test Program”) for the Waterloo silver-barite deposit. The 2022 Test Program is an initial investigation in the metallurgical process response of silver-barite mineralized rock at the Calico Silver Project (“Calico” or the “Project”), located in San Bernardino County, California.

In the 2022 Final List of Critical Minerals, published by the U.S. Geological Survey (“USGS”), barite was identified as one of many minerals which “…play a significant role in its national security, economy, renewable energy development and infrastructure.” The list was produced as the result of a mandate of the Energy Act of 2020, which was to identify minerals deemed essential to the economic or national security of the U.S. and which is vulnerable to supply chain disruption. Barite is critical for domestic metallurgical applications in the energy industry, with 90% of the barite sold in the U.S. used as a weighting agent in petroleum drilling. According to the USGS 2022 Mineral Commodity Report, the U.S. has an estimated net import reliance of more than 75% as a percentage of consumption and over half of that total is imported from China.

Barite quality analysis was completed at SPL Inc., (formerly Ana-Lab Corp.) in Kilgore, Texas, to determine if the concentrate produced met the API chemical and physical specifications for use as drilling fluids for the petroleum industry. The API is responsible for setting the quality requirements for all barite sold into the U.S. market. Results of this analysis are shown in Table 1 and demonstrate that the concentrate meets the API 13A (Barite 4.1) specification as defined in 2020.

As part of the 2022 Test Program several bulk flotation tests were completed on Waterloo silver-barite mineralized material to determine if a barite concentrate could be produced. Historical work by American Smelting and Refining Company (“ASARCO”) identified the potential to produce a salable barite concentrate, so the 2022 Test Program aimed to reproduce and improve upon these results. All barite related processing was performed at McClelland Laboratories Inc. (“McClelland”) of Sparks, Nevada.

Using 12 kg of composite 005, which had a calculated initial barite content of 18% (based on X-ray diffraction results) five tests were conducted to produce barite concentrates via flotation using Aero 845 promoter and sodium silicate as reagents. For the first four tests, flotation conditions and reagent additions were based on historical metallurgical testing reports of work done by ASARCO at Waterloo and Superior at Langtry. Material was initially stage-ground to 80% passing 212 microns, using a laboratory ball mill.

These four tests were conducted on 1 kg charges with a laboratory scale flotation unit at 1,200 rpm at 33% solids by mass. Following these, a fifth test using 8 kg of material was conducted using the indicated optimum reagent additions. Rougher flotation was conducted in five stages, with equally divided incremental additions of Aero 845 at each stage.

Rougher concentrate from the first three stages was subjected to two stages of cleaner flotation to produce the final concentrate. AEROFROTH 65 (polygycol) frother was used as needed throughout each test. Flotation products were all dried and analyzed for barium (by fused-disc X-ray fluorescence) and silver (by four acid digestion/ICP), with barite content calculated by McClelland based on reported barium content.

Further test work has been recommended to optimize the barite circuit and to determine the best method for integrating with cyanidation for silver extraction. This work would involve further flotation testing to better optimize procedures and include evaluation of barite flotation from cyanide tails and/or evaluation of concentrate cyanidation for silver recovery. Additionally, testing of other technologies is warranted (gravity concentration, attrition scrubbing) for separation of barite.

A review of the results by Apollo's Qualified Person for the 2022 Test Program, Eric Hill P.E., PMP, recommended that a preliminary case study be completed for the salability of a barite concentrate. Whole-core PQ-diameter diamond drill core used in the 2022 Test Program was collected by Pan American in 2012 and was drilled by Diversified Drilling, of Anaheim, CA. Core was logged (lithology, alteration, mineralization and geotechnical), and photographed in detail by Pan American.

The drill core was separated into 2 m intervals and crushed to -1.5 inch by McClelland. The material has been securely stored by McClelland in Sparks, Nevada, since that time. In 2022, each interval was thoroughly blended and split in half.

One half split of each interval was crushed to -1.7 mm and a 250 g split was taken using a rotary-type splitter. The 250 g splits were pulverized to better than 90% passing 106 microns. Major elements, including BaO, were analyzed using fused-disc X-ray fluorescence (“XRF”) (method ME-XRF26) with analyses completed at ALS-Reno.

Barite content of composite samples prior to flotation test work was calculated by McClelland based on XRF reported BaO content. Barite content of the composites was confirmed by X-ray diffraction analysis conducted by The Mineral Lab. Silver content in the barite concentrates was determined by McClelland using a four-acid digestion procedure with ICP-OES finish.

McClelland maintains its own comprehensive guidelines to ensure best practices in sample preparation and is an ISO 17025 certified facility. API testing of barite concentrate was completed by SPL Inc. (“SPL”), of Kilgore Texas, an analytical testing laboratory providing testing for petroleum and related products analysis, among other services, since 1944. Results of testing by SPL meet the requirements of the Environmental Protection Agency's National Environmental Laboratory Accreditation Conference.

All sample shipments were under strict chain of custody documentation. The 2022 Metallurgical Test Program was overseen and reviewed by Jared Olsen, P.E., a professional metallurgist at McClelland, and Eric Hill, P.E., PMP, whom was a professional metallurgist at Samuel Engineering Inc., and was Apollo's Independent Qualified Person for metallurgy, in cooperation with Derek Loveday, of Stantec Consulting Ltd., Apollo's Independent Qualified Person for mineral resources.