319 extensive bimodal volcanic sequences interlayered with thin BIF lenses. Its basalts also record intense hydrothermal alteration marked by abundant chlorite, zeolites and clay minerals (Martins et al., 2017). Figure 1 – Geological map of the N4 deposit 3. MATERIALS AND METHODS A literature review of the Carajás Mineral Province, combined with an evaluation of regional geological mapping data, identified the most prospective volcanic units as the Parauapebas and Igarapé Cigarra Formations, as well as associated mafic dikes and sills. Within Vale’s geological modeling framework, metabasalts are classified as waste in iron-ore resource and reserve estimation. However, for dilution calculations, contact intervals between waste and banded iron formation in drill cores are recovered, logged, sampled, and submitted to chemical and/or mineralogical analyses. As a result, the company’s exploration database contains a robust set of analytical information for the targeted stratigraphic units. Based on the distribution of chemical parameters required by Brazilian regulations for registering soil remineralizers, representative areas were selected for sampling and detailed study, considering only lithologies classified in the database as “fresh mafic rock.” A total of 34 samples were collected from 31 diamond drill holes across the Serra Norte mines (N3, N4, and N5), with depths ranging from 35 m to 350 m. In addition, three rock samples were collected directly from active mine benches in the N4E pit, where this lithology is either blasted to access
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