OPEN-PIT

The extraction of the pegmatitic rocks (LCT) from the "Romano" Mine will be carried out through open pit exploitation and surface cutting. In Open pit, using a precision surface mining process called Strip Mining. Contrary to explosive and underground drilling methods, this process optimizes the separation between the materials of interest and the rest, promoting a more effective initial separation and, thus, increasing its quality for downstream transformation processes. Strip Mining method consists of cutting or ripping material from the top of the deposit following a pattern pre-defined by surface miners (e.g., Vermeer T1255 Terrain Leveler). The cutting drum uses tungsten nozzles to fragment the rocks it crosses, and it will be mounted located at the back of the miner, cutting the material while the tracks advance over the ground yet to be cut. This equipment has a low centre of gravity that guarantees the best traction, keeping it balanced and stable. The surface miner to be used in open pit exploitation, has sophisticated automated systems, and has a suction instrument attached so that the dust emitted during the extraction process is completely reduced.

Top-down cutting system allows the nozzles to penetrate the ground without using the machine's traction effort. This technique gives operators the opportunity to control the size of the product by changing the cutting depth of the drum. The disaggregated material is left on the ground behind the machine, ready to be loaded and transported. Then, it will be stacked / grouped in stockpiles by bulldozers and loaded with wheel loaders to be transported by dumpers. It is also important to note that Vermeer surface miner will also be used in the construction and maintenance of ore transport roads, other access routes to and from the concession.
Part of the material will be taken to the Lusorecursos industrial unit, in order to be processed and chemically transformed. The remaining waste rock will be deposited in temporary landfills, and finally, used to fill the cavities resulting from the underground exploitation method.

UNDERGROUND

The mineral deposit is tabular in an east-west direction with a horizontal extension (strike) of about +830.00 m and an inclination of approximately 55° to 70° (Dip), with a maximum strength of the mineral deposit of 68 m, with respect to the "Romano" orebody. The ore is associated with pegmatitic dykes, in which the main exploration will focus on the main pegmatite called “Romano”. However, there are other dykes in the south of this one that must be exploited. The tabular geometry of the pegmatitic bodies makes their underground exploitation viable, as there is less waste rock extraction. Thus, it is assumed that the mineral dilution will be reduced, since the waste rock will not need to be removed and can be used to support the work being carried out underground, ensuring the necessary safety conditions.

It is necessary to carry out the excavations for its development and layout, at the production fronts (dismantling). The excavation of a Main Access Ramp (MAR - Main Access Ramp) is planned, with a gradient of about 10% to 11%, length of 1 600 m, which will serve for quick access to the other underground works of the mine and it will also provide for the circulation of trucks and other heavy machinery, as well as for the extraction of ore by conveyor belt. The development and layout of the mine will be to the south and the wall of the “Romano” deposit, so the Ramp will provide access and service to that area. The need for a second access to the mine is recognized, the Main Access Shaft (MAS-Main Access Shaft), which will serve as an emergency exit, transport of material for filling (Backfill) and as an alternative for ore extraction. The shaft’s proximity to the Pit minimizes transport as well as horizontal gallery excavation footage, good access to mine infrastructure (crushing plant, secondary ramps, developing and production cuts). Its location in a favourable geological and geotechnical zone implies less difficulties, lower costs, less excavation time, as well as enhancing the stability of the structure affecting the shaft. At this stage, specific equipment will be needed for underground work, as these must have specific characteristics, such as reduced dimensions, greater manoeuvrability and other attributes related to the confined environment.