Penco Module (Biolantanidos)

The Penco Module, formerly known as BioLantánidos, is a heavy rare earth project in Chile's Biobío Region, developed by Aclara Resources with Chilean partner CAP S.A. It would mine ionic adsorption clay for dysprosium and terbium, two of the heavy rare earths China placed under export controls in April 2025 (Aclara, October 2026). As of October 2026, the project held a first-stage environmental approval, faced two pending citizen appeals and had not started construction (BioBioChile; Diario Concepción; Aclara).

Where the Penco Module is

The project lies mainly in the municipality of Penco, in the Biobío Region of Chile (Aclara, June 2026). Aclara describes it as a 600-hectare ionic clay project (Aclara Q2 2026 MD&A).

Who owns the Penco Module (as of October 2026)

The project is held by REE Uno SpA, a majority-owned Chilean subsidiary of Aclara (Aclara Q2 2026 MD&A). CAP holds 20% of the project and has an option to raise its stake in REE Uno to 40%, subject to conditions the two companies agreed. Aclara says CAP would exercise it through a US$50 million investment when the project reaches a final investment decision (PEA release).

In 2019 Hochschild Mining bought 93.8% of the deposit, then called BioLantánidos, for US$56.3 million (Minería Chilena). The company developing it later took the name Aclara (BioBioChile).

What kind of deposit Penco is

Penco sits in the Chilean Coastal Range, where weathered granitoid rock has left clay-rich regolith holding exchangeable rare earths. The Penco granitoid complex hosts most of the mineralization. The mine plan covers five extraction zones: Victoria Norte, Victoria Sur, Luna, Maite and Alexandra (PEA release).

Aclara plans shallow open pits dug by excavator, with no blasting, crushing or milling (PEA release). Aclara's patented Circular Mineral Harvesting process is designed to recycle most of its water and its main reagent, a common fertilizer, and to need no tailings dam (PEA release).

Penco Module environmental approval and appeals (as of October 2026)

Aclara submitted the first-stage Environmental Impact Assessment in June 2024 (Aclara, June 2026). The Biobío Regional Environmental Assessment Commission approved it unanimously on June 8, 2026, and Chile's Environmental Assessment Service (SEA) issued the environmental qualification resolution (RCA) on June 22 (SEA project record; Aclara Q2 2026 MD&A).

The approval covers only the first stage: three extraction zones, the Neptuno deposition zone and the processing plant. Aclara says these support roughly the first 5.5 to 6 years of operations under its mine plan, giving both figures in the same release (PEA release). A second-stage assessment covering the remaining zones has not yet been prepared or submitted, and Aclara says second-stage approval cannot be assured (PEA release). Sectoral permits for construction are still needed (Aclara Q2 2026 MD&A).

In September 2026 the SEA admitted two of three appeals against the approval, from Penco social and Indigenous community groups and the Fundación Keule. Both appeals then went to Chile's Committee of Ministers for a decision (BioBioChile). As of October 13, 2026, the committee had not ruled, and Aclara had filed a brief on October 2 asking it to reject one appeal (Diario Concepción).

Timeline, cost and financing (as of October 2026)

Aclara's updated preliminary economic assessment (PEA), released October 19, 2026, models a 17-year mine life averaging 732 metric tons a year of rare earth oxides in a super pure rare earth carbonate, or SPREC (PEA release). It puts construction capital at about US$244 million, including contingency (PEA release). The company cautions that the PEA is preliminary and that there is no certainty it will be realized (PEA release).

Aclara now expects to finish a feasibility study in the first quarter of 2027. Subject to financing, it would start early works that quarter and full construction in the second half of 2027, and it targets completing construction in the second half of 2028 (PEA release). That schedule replaces an August 2026 plan to finish construction in the second quarter of 2028 (Aclara Q2 2026 MD&A). As of August 2026, Aclara was in commercial discussions with potential offtake buyers for Penco and Carina products (Aclara Q2 2026 MD&A).

Where Penco fits in Aclara's plans

Aclara calls its Carina project in Goiás, Brazil, its flagship and says it is also advancing Penco (Aclara Q2 2026 MD&A). In September 2026 it entered into an exploration joint venture agreement with Japan's JOGMEC for ionic clay deposits in Brazil (Aclara, September 2026).

Penco's SPREC would go to Project Dynamo, Aclara's planned separation plant at the Port of Vinton, Louisiana (Aclara, October 2026). Basic engineering finished in October 2026 added about 42% more dysprosium and terbium separation capacity to take Penco feed (Aclara, October 2026). Plant construction is targeted for completion in the second half of 2028, subject to financing and other conditions (Aclara, October 2026).

Why the Penco Module matters for heavy rare earth supply

Argus Media's market study in the PEA says heavy rare earth supply is more problematic than light rare earth supply because far fewer projects target heavy rare earth deposits. The study also says output from southern China's ion-adsorption ores is declining (PEA release). A review covered by REEx found Penco is the only Chilean rare earth deposit at the review's highest evidence tier (REEx news). REEx noted in June 2026 that the approval lowers permitting risk but does not amount to financing, an investment decision or production (REEx analysis).

Penco Module FAQ