Porto Trombetas (Mineracao Rio do Norte): a bauxite operation in Brazil

Porto Trombetas (Mineracao Rio do Norte) is an open-pit mine producing bauxite in Porto Trombetas, Para, Brazil, operated by MRN. The sources report 11,560 thousand tonnes ('000 tonnes), marketable quantities of ore plus concentrates for CY2025; the basis is 100% of the operation, reported by Rio Tinto as a 22% holder. Measured as bauxite, whole-operation output for CY2025 is 11,560,000 tonnes: about 2.6% of world bauxite output in 2025 and about 35% of Brazil's; it is one of 9 operations on this site whose output can be stated in bauxite.

Who owns and operates it?

Owners of Porto Trombetas (Mineracao Rio do Norte)
Owner	Interest	As of
Rio Tinto Rio Tinto's holding in the MRN joint venture. The annual report prints the shareholders as Rio Tinto 22%, Glencore 45% and South32 33%.	22%	31 December 2025
Glencore As printed in the Rio Tinto annual report.	45%	31 December 2025
South32 South32 prints a 33% interest in the MRN bauxite mine. Its annual report also says Alcoa will acquire South32's MRN interest under a binding conditional agreement announced on 1 July 2026, subject to conditions and to pre-emptive rights held by MRN's partners.	33%	30 June 2026

Interests are as stated in the sources below on the date shown. Ownership changes with deals, so a stake may have changed since the date shown.

How much does it produce?

Reported output of Porto Trombetas (Mineracao Rio do Norte)
Period	Output	Basis	Where in the source
CY2025	11,560 thousand tonnes ('000 tonnes), marketable quantities of ore plus concentrates Rio Tinto's 22% share of the same row is 2,543 thousand tonnes. The table does not say whether tonnes are dry or wet.	100% of the operation, reported by Rio Tinto as a 22% holder	PDF p.278 (printed p.276), section BAUXITE ('000 tonnes), row Porto Trombetas (MRN) (Brazil), 2025 Production 'Total' column; note 4 on PDF p.279 (printed p.277) · Rio Tinto
CY2024	11,523 thousand tonnes ('000 tonnes), marketable quantities of ore plus concentrates	100% of the operation, reported by Rio Tinto as a 22% holder	PDF p.278 (printed p.276), same row, 2024 Production 'Total' column · Rio Tinto

Between CY2024 and CY2025 the reported figure rose by 0.3%, in the same unit and on the same basis.

How the bauxite figure is worked out. The source reports 11,560 thousand tonnes for MRN in 2025 in the Total column of Rio Tinto's production table; the Rio Tinto share column prints 2,543 thousand tonnes at a 22.0% interest. Rio Tinto is a minority holder and does not operate MRN. The table gives marketable quantities of ore plus concentrates and does not say whether the tonnes are dry or wet. Converted from thousand tonnes to tonnes. World bauxite mine production in 2025 was 440,000,000 tonnes (USGS Mineral Commodity Summaries 2026); Brazil produced 33,000,000 tonnes.

Status: operating, as of 31 December 2025.

The figure comes from Rio Tinto, a 22% holder, not from MRN. MRN's own report is not among the sources used. The South32 annual report prints no MRN bauxite tonnage.
MRN output is shared by its owners and is not counted more than once; the Rio Tinto share of 2,543 thousand tonnes is not added to the whole-operation figure.
Alumina refineries and aluminum smelters, including the Alumar refinery, are separate from this bauxite mine entry.

How does it compare?

Other bauxite operations on this site: Weipa (including Amrun), Gove, Sangaredi (Compagnie des Bauxites de Guinee), Societe Miniere de Boke (SMB), Boffa (Chalco Guinea), Pingguo, Shanxi New Materials mines (merged line), Darling Range (Huntly and Willowdale), Juruti, Pocos de Caldas, Paragominas, Panchpatmali bauxite mines. In Brazil: Juruti, Pocos de Caldas, Paragominas. See where bauxite comes from for the country totals, the country page for Brazil, and MRN for its other operations here.

Sources

Rio Tinto: Rio Tinto Annual Report 2025 (annual report (filed with the U.S. SEC as an exhibit to Form 6-K), FY2025 (calendar), with 2024 and 2023 comparatives). Opened 4 November 2026; used: PDF p.29 (printed p.27), PDF p.160, PDF pp.278-279 (printed pp.276-277, Metals and minerals production), PDF pp.306-307 (printed pp.304-305, Group mines).
South32 Limited: Annual Report 2026 (annual report (ASX announcement 2026-08-27), FY2026 (July 2025 to June 2026)). Opened 4 November 2026; used: PDF pp.11, 28 (printed p.27), 35, 46.
U.S. Geological Survey: Mineral Commodity Summaries 2026: Bauxite and Alumina (government statistical summary, 2025 (world and country bauxite mine production)). Opened 3 November 2026; used: world mine production and reserves table.

Method and limits

Reported, not estimated. Output is the figure the operator or owner published, in the unit it used. This site does not estimate output where none is published.
Shares. A share divides output in bauxite by the USGS world or country total for 2025. Where the operator's year is a fiscal year or the unit is a concentrate or a carbonate equivalent, the share is approximate or not given.
What is compared. Operators print tonnes of bauxite on a dry or wet basis, or do not say which. USGS bauxite mine production is in dry tonnes, so where the basis differs or is not stated the share is indicative.
Whole operation or owner's share. The basis column says which. A joint venture's output is never counted twice.
Partial list. Only operations with a published figure are listed, so the rank is among those on this site, not among every bauxite mine. Shares of a country's output mix periods and bases, so treat them as indicative.
Made with AI assistance, checked against sources. The facts were gathered from the documents above by AI-assisted research and re-checked against those documents by a second, independent pass; the page text is generated from the data. No professional review took place. How the site is made. To report an error, contact us; fixes are logged on the corrections page.