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Operational Sequence

Land clearing, stripping, crushing, railway transport, loading and unloading of ore, washing and tailing handling, laboratory quality control, drying, bauxite storage, and ship loading. This section shows you how each stage in the production of bauxite works.

Bauxite Production

Our operations in Porto Trombetas consist in ore lifting, beneficiation, rail transport, drying and loading on ships.

The initial capacity of the company's bauxite production was 3.35 million tons per year. Throughout the history our operations, this capacity has expanded gradually, mainly due to increasing market demand and the wide acceptance of the bauxite produced by MRN by refineries around the world. Currently, our installed production capacity is 18.1 million tons per year – one of the largest facilities in this business in the world.

Today we operate the mines of Saracá V, Saracá W and Bela Cruz, where the ore lies at an average depth of 8 meters and is covered with dense vegetation and a layer of overburden made up by organic soil, clay, nodular bauxite and ferruginous laterite.

For bauxite to be mined out, first it has to be stripped off. This operation is done in a sequential manner in regular strips, where the overburden is excavated and dumped into the adjacent strip in which the ore was previously mined out.

After being mined out, the ore is loaded on trucks and transported to the crushing plant, where it is reduced to a particle size of up to three inches. From the crushers, the ore is transported on conveyor belts to the washing, cycling and filtering facilities.

As a result from this beneficiation process, approximately 25% of solid mass, known as bauxite tailings, is generated. The tailings are dumped into reservoirs built in mined-out areas on the Saracá plateau.

Once beneficiated, the ore is transported from the mine to the port along a 28-km-long railway. In this operation, trains with 46 rail cars each are used.

Since bauxite can be sold both wet and dry, from the port area the ore may have two destinations before being loaded on the ships: it either feeds the three drying furnaces of the Company or is stored wet in the storage yard.

The port's draft is enough to receive ships with a capacity of approximately 60,000 tons.

Tailing Disposal System

Our system for handling the tailings (clay from the washing of bauxite) consists of ponds constructed in mined-out areas, where the tailing is thickened, with no chemical additives and with an advantage: the water reclaimed from the thickening returns to the beneficiation plant in a closed circuit.

Operation support for tug maneuvers of dredges 
Operation of the pumping system in Lake Urbano 

After settling in the settling tank, after reaching 35% to 40% solids, the tailings are dredged and pumped out to other ponds built in mined-out areas. There, the tailings remain permanently, so that the wastewater is gradually eliminated, until conditions at the site allow for planting native species.

This process has been adopted by the company since the 1980s.When we started this system, the technology was unprecedented in the mining sector.


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