The Onca Puma mine is built on lateritic nickel deposits of saprolitic laterite ore.

Lateritic weathering profiles at Onca and Puma can be classified according to protolith mineralogy and the accumulation of quartz. Protolith mineralogy, the presence of significant chlorite and/or vermiculite in the serpentine #3 host at Puma distinguishes that deposit from Onca where the dominant Serpentinite #2 host is largely serpentine and chromite.

Each of the deposits has a saprolitic zone overlaid by a limonitic zone (if it has survived erosion). Nonsiliceous or normal profiles consist of serpentinite saprolite overlain by thin layers of limonite and in rare cases by some form o f ferricrete. Siliceous profiles are defined as having greater than 15% quartz in both siliceous saprolite and siliceous limonite. The limonite zones overlying tire On9a and Puma saprolites are generally thin, discontinuous, and from their chemistry consist of goethite, chromite, several manganese oxide phases, and sporadic amounts of quartz.

The principal minerals in the Onca saprolite in decreasing order of importance are serpentine, limonite, quartz, chromite and vermiculite. Ni occurs in solid solution largely in serpentine with subordinate amounts in goethite (=limonite) and vermiculite. Minor amounts of various green silicates, “gamierites” intergrown with chalcedonic quartz, are seen locally in Onca saprolite; grains of possible nepouite contained 13-19 wt% Ni have also b ........

Onca Puma is an open pit nickel mine which is located at Para in Brazil. Ore is extracted from nickel laterite deposit via conventional truck and sovel method.

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