The regional geology of the Monte do Carmo area is characterized by a volcano-sedimentary sequence of Upper Proterozoic age, intruded by a large granite body of Lower Proterozoic age. The gold mineralization at Serra Alta is associated with a granite cupola. It is interpreted to fit into the Intrusion Related Gold System style of mineralization, very similar to the Fort Knox Deposit, Alaska, USA.

Serra Alta gold mineralization is associated with hydrothermally altered and sheared granitic rocks with quartz vein and veinlet swarms, moderately rich in sulphides (pyrite, galena, sphalerite and chalcopyrite). Other gold mineralization in the region is often hosted in single large quartz veins within fractures (the Giant Quartz Veins target).

The mineralized granite is overlain by a quartzite which caps the cupola. A much younger sequence of flat lying red bed sediments overlies the quartzite. The quartzite and red beds form cuestas (mesa-like features) several hundred metres high and will likely limit any push back of a pit wall to the east.

The Giant Quartz Veins are located about 5 km to the south of Serra Alta in the same granite body. Their width varies from just under a metre to several metres.

Serra Alta Mineralization
The Serra Alta Deposit is a wide mineralized zone about 300 m wide with approximately 1,500 m of exposed strike length. The zone is a corridor which contains veined, mineralized shoots generally striking N10°, dipping 60° to 80° W.

At the time of the QP’s site visit, MSM and Cerrado geologists were discussing the possible interpretation of three distinct sub-corridors or trends of mineralization within this wider corridor. It is possible that the far western trend is composed largely of colluvium shed from the slope and the artisanal workings there may have no immediate bedrock source. There are exposed bedrock sources of veining on the eastern side up against the cuesta wall. Extensions of the sheared granite cupola mineralization on the eastern side, under the quartzites, have been confirmed by drilling.

The field information obtained in the Serra Alta Deposit small pits mined by MSM caused it to classify the gold mineralization hosted in the cupola portion of the granite under the Reduced Intrusion Model. The mineralization occurs within a system of veins and veinlets commonly associated with zones of hydrothermal alteration. This system of veins and veinlets is characterized by quartz associated with gold and sulphides (pyrite, arsenopyrite galena, sphalerite and chalcopyrite), whereas the hydrothermal alteration is characterized by phyllic and propylitic alteration zones, as well as sulphidation and silicification.

The granite hosts a system of intersecting northeast-southwest- and northwest-southeasttrending veinlets, which occur in most areas of the deposit.

The northeast-southwest-oriented vein system is millimetre- to centimetre-scale, but tends to be thicker and truncates the veins and veinlets of the older system. These veins are predominantly composed of milky quartz crystals, moderately fractured and medium to coarse grained. However, they exhibit borders and internal zones of expansion, often filled by sulphide minerals and gold, as well as rare aggregates of white mica + chlorite + carbonate. In this system, free gold can also occur, filling cracks in the quartz veins.

Occasionally a re-opening and filling phase of the northwest-southeast system is identified, passing through the northeast-southwest milky quartz vein system. This represents the last stage of dilation recorded in the granite dome. It is filled with aggregates of chlorite + white mica + carbonate ± pyrite as veinlets.

Three types of hydrothermal alteration, propylitic alteration, sulphidization and silicification, occur at Serra Alta. However, these hydrothermal zones usually appear overlapping each other, making it difficult to determine a better temporal analysis of the events.

The mine design is based on using standard open pit mining techniques of drill, blast and haul using contract mining to reduce upfront capital needs. GE21 has developed a mine plan which processes 13.23 million tonnes of the current resource base over a 7-year mine life at an average strip ratio of 7.79 to 1. Mining will reach a peak of material movement of approximately 1.89 million tonnes per annum.

As outlined in the PEA technical report, the initial metallurgical test work supports the gold recovery by gravity concentration followed by tailing flotation. Both concentrate coming from gravity and flotation are leached in an Intense Leaching Reactor (ILR). The results of the test work confirmed the recoveries of 97%. The processing plant designed for Monte do Carmo is a simple gravity circuit with a small flotation and leach plant to recover the gold using standard equipment and technologies.