La Colorada is a typical epithermal silver-gold deposit, with a transition in the lower reaches of the deposit to a more base metal predominant system.

There are three separate active mining areas on the property, including the Candelaria, Estrella, and Recompensa areas. The main structure at Candelaria strikes generally east west. The west part of the vein is referred to as HW and the east part is referred to as NC2, and there are a number of off-splits from these veins. The Estrella area includes the Amolillo vein, which is a split from the HW vein, and the Palomas vein, which is a split from Amolillo. The Recompensa zone produces or has produced from three areas: the Recompensa vein; Erika, which is a split from the Recompensa vein; and the Yuri replacement body, which lies between Erika and Recompensa.

Four dominant styles of mineralization are present at La Colorada, including breccia pipes, vein-hosted mineralization, replacement mantos within limestone, and deeper seated transitional mineralization.

Mineralization in the breccia pipes generally has lower silver values and elevated base metal values. Mineralization is associated with intense silicification and occurs as disseminated galena and sphalerite with minor chalcopyrite and bornite. Sulphides are found in the clasts and the matrix.

Most mineralized veins on the property strike east to northeast and dip moderately to steeply to the south. Veins occur in the dacite and limestone units and cut across the bedding and contacts with little change in the width or grades of the vein. Mineralized widths in the veins are generally less than two metres, but may be wider in the presence of a surrounding halo of replacement or brecciated material. The HW Corridor at the Candelaria mine strikes east-west and dips moderately to the south, with true widths of approximately up to 15 metres, but most of the economic mineralization is located in quartz veins, which are on average one to two metres wide. In some cases vein fillings consist of quartz, calcite, and locally barite and rhodochrosite. Where the veins are unoxidised, galena, sphalerite, pyrite, native silver, and silver sulphosalts are present. The major mineralized veins are strongly brecciated and locally oxidised.

Manto style mineralization is found near vein contacts where the primary host rock is limestone. This style of mineralization was previously mined at Recompensa and is also present in areas of the Candelaria zone. The mantos appear to be controlled by thrust faulting adjacent to the veins, and can form bodies up to six metres wide. Most commonly, they occur in the footwall north of the steeply dipping vein, but depending on the orientation of the fault they can occur in the footwall, the hanging wall, or both. The mineralogy of the mantos is characterized by galena and sphalerite with minor pyrite and chalcopyrite. Gangue minerals include quartz, rhodochrosite, pyrolusite, and other manganese oxides.

The deep seated transition mineralization, also known as NC2 Deep at the Candelaria mine, consists of both vein type mineralization and more diffuse stockwork and breccia zones. There appear to be seven distinct zones within the transitional zone, and these can be subgrouped into three main categories: vein mineralization, including the down dip extension of the HW and NC2 and veins in the hangingwall and footwall of both; a peripheral stockwork vein zone that envelopes the NC2 structure; and sub-horizontal manto-like stockwork zones in the NC2 hangingwall.

The NC2 and HW Corridor veins at the Candelaria mine are economically the most important and contain over 40% of the mineral reserve and resource ounces of silver. These zones are characterized by a broad mineralized shear within limestone containing one or more quartz veins parallel to the orientation of the shear. The majority of the silver mineralization is found in the quartz veins which range from 2.0 to 2.9 metres wide. The HW and NC2 structures provide nearly 90% of the mine’s current production. The two veins have a combined strike length of over 1,500 metres.

The NC2 vein is the most important source of sulphide silver mineralization and contains approximately 30% of the mineral resource and reserve ounces of silver. It is a narrow, one to seven metre wide mainly sulphide and partly oxide vein with a strike length of over 900 metres. It is open to the east where it is cut by a trachyte dyke, and has been confirmed by drilling and drifting to continue in both width and grade on the other side of the dike.

The HW vein, also at the Candelaria mine, is a one to two metre thick vein with a strike length of over 1.1 kilometres. The HW Corridor consists of four structures. Two structures are brecciated-altered zones in the hangingwall of the HW vein, and the other two structures of the footwall are controlled by a broad mineralized shear in limestone containing one or more quartz veins parallel to the orientation of the shear. The majority of the silver mineralization is found in the quartz veins which average two metres wide but can widen up to six to seven metres at the intersections with the HW vein.

At the Estrella mine, the Amolillo oxide/sulphide vein is located 500 metres north of the NC2 and HW vein complex and approximately along strike to the east of the Recompensa vein. The vein lies mostly within dacite host rock and limestone at depth, and has an average width of 1.9 metres and a strike length of approximately 1,300 metres. Our drilling results indicate that the Amolillo vein could be key to a possible mine expansion, as indicated in the La Colorada Report. Diamond drilling has intersected the vein 480 metres below the deepest mining level, and expanded the lateral extension to the east and west by 900 metres for a total of 1,300 metres of current strike length.

The Recompensa mine contributes the fewest silver ounces to the mineral resources and reserves. The main zones being exploited are the Recompensa and Erika veins and the Yuri manto replacement body located between the two veins. The Recompensa and Yuri are located more than a kilometre northwest of the NC2 and HW vein complex. The vein mineralization averages about 1.8 metres wide in the economically mineable zones, and contains a minor amount of oxide but mostly sulphide material. Erika is a hangingwall split from the Recompensa vein and is relatively narrow at an average width of 1.0 metres in the economically mined zone. It contains only sulphide material.

La Colorada produces oxide and sulphide ores from the Candelaria, Estrella and Recompensa underground mines. The amount of oxide material mined each year has decreased as the mine progresses deeper in the system. The La Colorada Report projects that approximately a quarter of the material mined during the remainder of the currently planned mine life will be oxide and sent to the oxide process plant while the remaining three-quarters will be sulphide and processed in the sulphide plant.

The mining method used at all three mines is cut and fill stoping. This method allows for improved ore recovery and selectivity from irregular, steeply dipping veins. Ground support is provided by rock bolts, with screen and shotcrete as required, as well as by backfilling the voids created by mining with development rock or mill tailings as the ore extraction advances.

Oxide and sulphide ore is treated in separate oxide and sulphide plants. The oxide plant comprises a conventional cyanide leach plant consisting of crushing, ball mill grinding, leaching, Merrill-Crowe zinc precipitation, and on-site refining to produce silver and gold doré. The sulphide plant is a conventional flotation plant comprised of crushing, ball mill grinding, and selective lead and zinc froth flotation circuits to recover silver, gold, zinc, and lead into separate lead and zinc concentrates.