The Rodeo property hosts gold- and silver-bearing mineralization commonly associated with a low-sulfidation (adularia-sericite) epithermal mineralizing system. Epithermal systems are defined to occur from depths of less than 2 km to superficial hot spring settings. Mineral deposition occurs as hydrothermal fluids undergo cooling and degassing and are commonly zoned vertically over 250 to 350 m from a base metal-poor, gold- and silver-rich top to a relatively silver-rich base metal zone and an underlying base metal-rich zone grading at depth into a sparse base metal, pyritic zone.

The immediate Rodeo deposit area is approximately 300 m along strike and 200 m wide and extends to a depth of 200 m below surface. The deposit strikes at 330° and dips to the ENE with various vein phases dipping from sub-vertical to 30°. The deposit is entirely hosted within Tertiary Rodeo volcanics that are strongly silicified and brecciated. The deposit is bounded to the east by the Rodeo Fault, however drilling to date has not demonstrated that the deposit reaches or is truncated by the fault. Along strike to the north and south, the mineralization is offset slightly by near vertical faulting; mineralization does not terminate at these faults, but the intensity of the trend is either diminished or high-grade mineralization has yet to be located.

Mineralization at the deposit is epithermal low-sulfidation (quartz-adularia) type. Although very little mineralization is hosted in or centered on the Rodeo Fault itself, it is possible that the fault played a role as a pathway at depth for the Rodeo deposit. Quartz veins 15 m or greater in width have been located throughout the property. The high-grade Au mineralization appears limited to a distinctive veining event. Evidence of ancillary veining events pre- and post-dating the high-grade event carry low-grade to anomalous level of Au mineralization.

The gold event is associated with a restricted vein stage characterized by small smoky quartz veinlets cut by banded blue opaline quartz and later brecciated and cemented by glassy smoky quartz hosting very fine disseminated pyrite. In the main zone, the veinlets generally trend NNW and dip steeply to the east or west, but the core angle in some drill holes suggests these veins may also have developed along ENE to EW structures. The envelope of the high-grade event appears to be restricted to a preferential volcanic layer or elevation (or both). Movement on the Rodeo Fault is likely responsible for the current orientation of the envelope.

Due to the near-surface nature and continuity of the orebody, mining at Rodeo is conducted with open pit mining methods. Blasted material is mined with a diesel excavator and loaded into on-highway trucks for haulage to the plant site approximately 115 km away from the mine. Loading and hauling to the plant is typically carried out on the weekdays during the morning, to ensure adequate mineralized material delivery while allowing for mining of waste and low-grade materials to occur later in the day. If needed to supply mill feed, haulage to the plant may continue over the weekend. Separating the mining activities based on haulage destinations allows for more efficient use of resources, while creating a safer working environment.

There are four stockpiles at the mine site for stockpiling mineralized material for potential future processing, and additional stockpiling area exists at the plant to allow for better material management and potential blending. Mine production averages 2,100 tpd of total movement and the pit has an expected mine life of 22 months. Figure 13-1 shows the final pit outline for the Rodeo Project. Mining is conducted in 5 m benches which are double benched to 10 m.

Mining and hauling to the plant are carried out using contractors. Labor requirements are minimal and are provided by the contractor. Golden Minerals personnel are responsible for blasthole sampling, supervisory, administrative, and engineering tasks.

A jaw crusher followed by a cone crusher provide primary and secondary crushing of feed material. Crushed material enters a grinding circuit comprised of a 10.5 x 13 ft ball mill and a recently installed 8 x 22 ft regrind (secondary) mill, both in closed circuit with cyclones.

Mineralized material from the Rodeo mine is hauled approximately 115 km via on-highway trucks and stockpiled for process at the agitated leach plant in Velardeña, Durango (Plant 2). The plant is owned by Minera William S.A. de R.L. de C.V. and operated by Servicios Velardeña S.A. de C.V., both wholly owned subsidiaries of Golden Minerals. The plant has a design maximum throughput of 520 tpd and is currently operating at an average rate of 500 tpd.

The product from the mills at 80% passing 325 mesh is thickened and sent to a series of eight agitated lixiviation tanks where cyanide is added with a planned consumption of 3.0 to 3.1 kg/t, and precious metals are leached from the mineralized material at a design flow rate of 1,700 m3/day and a total leaching time of 84 hours. Rich solution is separated using countercurrent decantation and sent to the Merrill-Crowe circuit for clarification and precipitation of the gold and silver that is then refined into gold and silver doré b ........