The Don David Gold Mine (DDGM) area is predominantly volcanic rocks of presumed Miocene age, which overlay and intrude into basement rocks consisting of marine sediments. This district's gold and silver mineralization is related to the volcanogenic system and is considered epithermal in character.

The DDGM mineralization occurs as structurally controlled epithermal deposits in veins and stockwork zones. The mineralization is associated with gangue minerals such as quartz, calcite, and other minor elements. Primary sulfide mineralization consists of pyrite galena, sphalerite, chalcopyrite, and different minor amounts of argentite and silver sulfosalts. It consists of concentrations of sulfides containing gold, silver, lead, copper, and zinc.

DDGM exploration efforts have been mainly focused on the Arista Project, which contains the Manto Vein, Arista, and Switchback vein deposits, and includes the significant Arista, Baja, and Soledad veins as well as multiple ancillary structures. The principal hosts of mineralization are the Arista and Switchback vein systems, known from drilling and underground workings in the Arista underground mine. The Switchback deposit is approximately 500 m northeast of the Arista deposit. Both vein systems are andesitic host rocks, rhyolite dikes, and structural contacts with the basement sedimentary rocks. The mineralization in these systems is intermediate sulfidation with precious and base metals at economic grades. Both vein ........

Historically, companies have produced ore from two locations on the Arista mine, the open pit mine and the underground mine. The open pit mineralization is considered low sulfidation, epithermal mineralization primarily of gold with some silver and no base metals. In 2021, mining activities were completed in the open pit, and it will now become the site for filtered dry stack tailings deposition. The Arista underground mine is considered intermediate epithermal mineralization of gold, silver, copper, lead, and zinc. The host rock in the Arista vein system is primarily andesite.

Conventional drill and blast methods are used to extract the Mineral Resources from the Arista mine at the Aguila project.

There are two main mining methods used in the Arista mine: 1) overhand mechanized cut and fill (CAF) and 2) long-hole open stoping (LHOS) with delayed fill. Paste fill, cemented rock fill and uncemented rock fill are applied to long-hole stoping areas in order to increase extraction levels (removal of rib pillars), CAF uses uncemented rock fill as a backfill method.

For the stoping methods, a crosscut from the main ramp intersects the vein, from which an initial drift is excavated perpendicular in both directions along the strike length of the vein. Once the economic limits of the vein have been reached the production cycle starts.

Overhand Mechanized Cut and Fill (CAF)
A CAF stope is started by means of a short (40 to 60 meter) nega ........

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The processing plant has a differential flotation circuit capable of processing polymetallic ores and producing up to three separate concentrate products for sale and an agitated leach circuit capable of producing gold and silver doré for purchase. The DDGM mill flotation circuit and agitated leach processing capacities are a nominal 2,000 tpd.

DDGM currently mills and processes the Arista and Switchback underground mines ore through the flotation circuit at the DDGM Processing Facility. The Don David Gold Mine processing plant was built near the mine site and consists of both a sequential flotation (sulfide) circuit and an agitated cyanide leach (oxide) circuit. The flotation circuit produces three separate concentrate products (gold-copper, silver-lead and zinc) from polymetallic ore extracted from the Arista/Switchback underground deposits. The agitated cyanide leach circuit processes ore mainly from the Manto Vein open-pit. The Manto Vein open pit was depleted in May 202 ........