The Concepcion Del Oro district represents a porphyry copper deposit that has been eroded down to a relatively deep level, as evidenced by the outcropping skarn alteration. Skarn alteration is barren unless the skarn is overprinted by the later porphyry style alteration marked by propylitic, phyllic and potassic alteration types. Trace metal geochemistry supports the classification of Concepcion del Oro as a porphyry deposit. Strongly anomalous bismuth, tellurium, arsenic and antimony are present and are typical trace metal assemblages associated with porphyry copper deposits. This trace metal assemblage is most anomalous in areas of phyllic and potassic alteration.

The mineralization in Aranzazu has a strike length of 1.5 km, a width of up to 250 m and depth extents up to 600 m. The Aura Minerals’ exploration and definition drilling shows that mineralization is closing off at BW, Mexicana and AA but open at depth in Glory Hole Porfido zone. The deepest drilling conducted to date was carried out by Aura Minerals indicated the presence of strong copper mineralization at an elevation of 1,500 m, or 600 m below surface.

Copper, gold and silver mineralization occurs in a porphyry alteration assemblage related to the intrusion of an igneous rock complex consisting of quartz monzonitic to granodioritic rocks. The igneous rocks have intruded a sequence of Jurassic to Cretaceous limestones and siltstones. The sedimentary rocks have undergone contact metasomatism and skarnification and now represent a group of rocks ranging from endoskarn and exoskarn, proximal to the intrusive, to marble, distal to the intrusive. Hornfels is present and reflects the contact metasomatic alteration of clastic rocks. Porphyry alteration consisting of propylitic, phyllic and potassic alteration overprints the skarn, quartz monzonite and, in some areas, marble and hornfels. The porphyry alteration is the mineralizing event that deposited the suite of metals that comprise the mineral deposits of interest.

The copper mineral species present in the different zones vary depending on the alteration style that is prevalent. In the BW zone, host to propylitic alteration, the copper mineralization is mostly chalcopyrite. Copper mineralization present in phyllic and potassic alteration styles is chalcocite, copper sulphosalts, chalcopyrite and bornite. The trace metal assemblages also vary depending on the copper minerals present. The BW zone contains moderate amounts of arsenic, but is relatively low in antimony, bismuth and tellurium. In areas of phyllic and potassic alteration where multiple copper mineral species are present, the amounts of arsenic, antimony, bismuth and tellurium increase.

Other phases of mineralization are evident in the Concepcion Del Oro area. Zinc-lead-silver deposits are noted as discrete, relatively small chimney and manto deposits. The zinc-lead-silver mineralization phase is present as both distal deposits relative to the Arroyos Azules copper mineralization and as late stage mineralization that postdates and cross cuts the Arroyos Azules copper mineralization.

Some skarn and intrusive zones contain high concentrations of molybdenum. Often garnet skarn contains several percent of coarse grained molybdenum and it is also common in veins which cut skarn and intrusive. Molybdenum occurs within weakly propylitized endoskarn and exoskarn, though it is not clear from geological relationships where the molybdenum mineralization occurs paragenetically relative to the copper and zinc- lead-silver pulses of mineralization. Molybdenum grades do not return assays that would be considered economic.

Gold mineralization occurs throughout all of the alteration phases previously mentioned with the exception of skarn alteration. Gold grades are generally higher in the phyllic and potassic alteration assemblages compared to propylitic altered rocks.

The Aranzazu underground mine is accessed by two portals which are near the processing plant. Main ramps, driven at 5m high by 5m wide are used to access the underground workings. For the re-start plan, two (2) new ramps are designed to access the GHFW and GHHW zones. Ramps are designed at the same dimensions, with an average gradient of approximately 14.2%.

Mining will be carried out using the Sub-Level Open Stope (SLOS) mining method to extract the ore. Stopes will be extracted in a transverse method (perpendicular to the strike of the orebody) using a primary/secondary stope configuration. In this mining method, haulage galleries are developed parallel to the ore zones on each production level as defined by the sub- level interval. Sub-level intervals are designed between 25 to 30 meters to minimize the amount of waste development on the sublevels. While the majority of the stopes will be mined transverse, there are some areas that will allow the ore to be extracted in a longitudinal approach. Stopes are to be filled with cemented rockfill for primary and uncemented waste material for secondary stopes.

The mine development and production schedule were developed using the Deswik® software package. The sequence for both development and production activities was developed and the appropriate rates and production targets were applied to achieve the required schedule of activities. During the first year, development will focus on the GHFW ramp and level development, as well as establishing access to the existing mining zone. Ore production will begin within the first 3 months from easily accessible areas; however, it will require a ramp up period of approximately 14 to15 months to reach full production of 2,600 tpd.

It is intended to use a mining contractor to do all the development and stoping, haulage of ore to the mill and placement of backfill. Aranzazu will provide the main services, such as ventilation, de-watering (pumping), compressed air and electrical reticulation along with technical services.

Ventilation will be provided by two 2.35m diameter Axial Mine Fans. Fresh air will intake through the main portals and exhaust through ventilation raises. The pumping system is designed to handle 40 to 45 l/s of water. Water will be pumped in multiple stages from the bottom of the mine to a central clarifier sump. Clean water will be pumped to the surface storage ponds.

For the existing areas of the mine, electrical power will be provided from the existing sub- stations on surface feeding at 4.16 kV. A new sub- station will be installed to supply power to the new sections of the mine (GHFW and GHHW zones) at 13.6 kV. Compressed air and water will be supplied using the existing systems.

The existing concentrator facility was first commissioned under Aura in 2011. The existing flowsheet is conventional and comprises crushing, grinding, flotation and dewatering systems. Ore is concentrated to a final concentrate grade of 23% Cu in rougher flotation with a scavenger flotation stage the concentrate from which is recycled back to rougher feed.

The major improvements that are expected to be made in recovery of both copper and gold, compared to the previous operating period from 2011 to 2014, will be due to a finer grind from a coarser p80 of 207 microns to 135 microns and the effect of receiving much higher ore grades. The finer grind will be achieved by using the regrind mill as a primary mill and by improved control of the grinding circuit with automatic control of water addition and a much improved system for ball addition which will ensure that the mills are drawing full power.

The revised operational setup includes an on- stream analyser that will provide copper and arsenic analysis of the ore feed, concentrate, scavenger concentrate and tailings every 10 minutes and will assist the operators to provide much better control of the circuit both in maintaining concentrate grade and metal recovery.

The metallurgical recoveries based on recent testwork resulted in 88% copper, 69.9% gold, 70% silver and 83% arsenic. Throughout the metallurgical testwork, the copper to arsenic ratio (Cu/As) was deemed to be a reliable indicator for final arsenic grade in final concentrate. If low Cu/As ratio (less than 7.7) ore were to be received in the concentrator this could result in the production of out-of- specification final concentrate; under this scenario, the concentrate will be stockpiled and blended with that produced during the times when the ore has a copper to arsenic ratio above 7.7.

The concentrator has been evaluated for structural, electrical and mechanical flaws and is being brought up to a more modern standard in terms of process control and instrumentation. Concentrate dewatering will be improved with automatic control of the pulp density in the concentrate thickener underflow and with the addition of more plates on the concentrate filter.

The process water supply is being improved with larger pumps and some pipeline replacement in the existing supply system and a supply from a disused refurbished well close to the concentrator.