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Favourable Metallurgical Results from Avino’s Oxide Tailings Project

Press Release

Avino Silver & Gold Mines Ltd. (ASM: TSX/NYSE American; FSE: GV6, “Avino” or “the Company”) a growing silver producer in Mexico, is pleased to announce metallurgical results from the testwork program on its oxide tailings project (“Oxide Tailings” or the “Project”). The Project hosts gold and silver from past producing historic operations in an inactive tailings facility located on the Avino property with a 5.7 million tonnes of measured and indicated resource grading 95 g/t of silver equivalent. Historically, near surface oxidised material was not recovered well by Avino’s conventional flotation mill, which has created this opportunity for re-processing the tailings with a cyanide leaching process.

These results below will form the basis for the metallurgical analysis of a Pre-Feasibility Study (“PFS”) on the Project.

In addition, a table can be viewed at the end of this release showing a comparison between the 2021 and 2023 mineral resource estimate on the Oxide Tailings as contained in the respective technical reports which can also be viewed on Avino’s profile on SEDAR.

“We are very pleased with these metallurgical results, which demonstrate excellent metal recoveries that would be suitable for a precipitating into bullion,” commented CEO David Wolfin. “Metallurgy is an important component in understanding the potential economics of our Oxide Tailings project. This Project has been in our portfolio for many years and factors prominently into our five-year growth plan to become an intermediate silver producer in Mexico. These results also build on the work done in 2017 Preliminary Economic Assessment (“PEA”) and increase the level of confidence in the Project from the extensive testwork completed. When comparing the most recent mineral resource estimate to the one completed in 2021, we see in the measured and indicated category an impressive 408% increase in tonnage, as well as a 287% increase in AgEq ounces. The potential of the Oxide Tailings resource has been known for many years but buried under the active tailings dam. With the new state of the art Dry-Stack Tailings facility now fully operational, we can advance the oxide tailings project to the prefeasibility study level. These results along with the ongoing testwork program will allow us to make sound decisions on the processing route to maximize the project value.”

Highlights of Metallurgical Test Results

The project consists of three types of tailings that are categorized by grade as well as identified in three stratigraphic layers within the deposit based on the time period when they were processed. They are, Ancient Oxides, Recent Oxides and Sulphides, and each type was sampled and tested separately. The average grades are shown below.

Table 1: Average Grade of Each Tailings Type

Sample Description Au g/t Ag g/t
Ancient Oxides Original
Recent Oxides Original
Sulphides Original

The project exhibits an excellent response using conventional metallurgical techniques.

Recovery Highlights include:

Ancient Oxides
Gold Recovery up to 89.5% and silver recovery of up 90.4% in a conventional bottle roll.

Recent Oxides
Gold Recovery up to 85.8% and silver recovery of up 83.4% in a conventional bottle roll.

Gold Recovery up to 82.8% and silver recovery of up 76.1% in a conventional bottle roll.

The conventional bottle roll test parameters for the three samples were achieved at a particle size of eighty percent passing 75 microns using 500 to 1000ppm sodium cyanide and a retention time of 60-72 hours. The metallurgical test program was completed by SGS de Mexico (“SGS”), a leading metallurgical testing and consulting firm based in Durango Mexico. The testwork was completed on a composite sample from approximately 437 kg of HQ core from a sonic drill from 127 drill holes drilled into the oxide tailings resource in 2021 and 2022.  Each type of tailings was identified and separated so that a composite for each style of tailings could be created. Both the deposition style and appearance of the tailings within the drill core allowed for relatively straight forward categorization. The sulphides section used 158.9 kg of sample, the ancient oxides used 135.5 kg and the recent oxides 142.7 kg.

The testwork program included chemical analysis, size fraction analysis, agglomeration, bulk leaching extractable gold test,  bottle roll test to simulate agitated leaching, column leaching tests to simulate heap leaching, flotation, and cyanide detoxification using sodium hypochlorite.

Testwork Program Results

Flotation was investigated at a variety of grind sizes, reagent levels and operating conditions. A Bulk leach extractable gold test was performed to understand the leaching response of each respective size fraction on each sample. While each size fraction of each sample did show a variation in leaching performance it was determined that there were not significant portions of gold locked away rendering any sample unleachable. With that in mind, various leaching conditions and three particle sizes were investigated per sample. Each sample performed best with a 75um (“micron”) grind size, furthermore it did not appear that the addition of lead nitrate or oxygen provided superior leach results. Finally, a column leach test was performed on each sample in order to replicate the performance of a potential heap leach.  The flotation, agitated leach and column leach results are shown per sample are shown below.

Table 2: Summary of Recoveries for the Sulphides Sample

Description Au
Agitation leaching
Heap leaching

Table 3: Summary of Recoveries for the Ancient Oxide Sample

Description Au
Agitation leaching
Heap leaching

Table 4: Summary of Recoveries for the Recent Oxide Sample

Description Au
Agitation leaching
Heap leaching

Ongoing Testwork

In addition to these leaching and flotation results, ongoing testing consists of the thickening, filtering, communition optimization, cyanide detoxification, gravity testwork as well as specific gravity and bulk density testwork that will be fed into the PFS for appropriate flowsheet design, sizing and costing.


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