Mineral Deposit Types
The San Jose de Gracia and Alta Gracia gold-silver sub-districts of the Don David Mine are characterized by classic, high grade silver-gold, epithermal vein deposits with low to intermediate-sulfidation mineralization quartz-adularia-sericite alteration. The veins are typical of most epithermal silver-gold vein deposits in Mexico with respect to the volcanic or sedimentary host rocks and the paragenesis and tenor of mineralization. The Alta Gracia mineralization is typical of a low sulfidation deposit. The Arista mine vein systems are intermediate-sulfidation in nature and standard of many Mexican deposits, characterized by Camprubí & Albinson, 2007, and described as Polymetallic Ag-Au by Corbett.

Description of Mineralized Zones
The Don David Mine mineralization occurs as structurally controlled epithermal deposits in veins and stockwork zones consisting of concentrations of sulfides containing gold, silver, lead, copper, and zinc, associated with gangue minerals such as quartz calcite and other minor minerals. The economic mineralization at the Arista Mine is gold, silver, copper, lead, and zinc. Structurally controlled epithermal veins and stockwork zones at Alta Gracia Project (Mirador Mine) contain mainly silver-gold bearing sulfides. The economic mineralization currently exploited at the Alta Gracia Project is only gold and silver.

Primary sulfide mineralization within the mineralized structures contains pyrite, gale ........

In 2021, mining activities were completed in the open pit, and it will now become the site for filtered dry stack tailings deposition.

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) negative 15 percent access ramp usually in the footwall of the vein to provide access to the bottom of the mining block. The ore is then mined in 3-meter horizontal slices using a Jumbo drill (Figure 13.3). The jumbo will drill 4-meter long essentially parallel and horizontal 1-3/4-inch holes that will later be charged with explosives to “breast down” and break the ore.

The length of these mining blocks can vary from 50 to 250 meters in strike length. After the first slice or cut is complete, the void will be filled with loose waste rock to form the floor of the next cu ........

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