Rain City Resources Inc. (CSE: RAIN) announced on September 15, 2026 that its Chilean subsidiary, Rain City Resources LATAM SpA, has signed a Scientific and Technological Evaluation Agreement with Quiborax S.A., a major Chilean mining and chemical company recognised as the world's third-largest boric acid producer. The agreement establishes a framework to evaluate Rain's AC²ME extraction and processing platform using Quiborax materials, including opportunities linked to lithium and other critical minerals. The collaboration centres on Quiborax's El Águila project, which holds regulatory approval to recover up to 20,000 tonnes of lithium carbonate equivalent (LCE) from historic processing residues by December 31, 2046.

Key Points

  • Rain City Resources Inc. (CSE: RAIN) is a Calgary-based critical minerals technology company
  • Rain City Resources LATAM SpA has signed a Scientific and Technological Evaluation Agreement with Quiborax S.A. to test Rain's AC²ME lithium recovery technology
  • El Águila studies referenced in the CEOL process identify approximately 19,775 tonnes LCE in historical processing residues; the CEOL authorises up to 20,000 tonnes LCE or operations through December 31, 2046
  • Investors may be watching whether AC²ME demonstrates the technical and economic performance required to progress toward a commercial arrangement

El Águila's Landmark CEOL Approval Creates Rare Private Lithium Opportunity in Chile

The El Águila project holds particular regulatory significance because it is the first CEOL process involving a wholly private company under Chile's current lithium policy expansion to receive Contraloría approval of its governing decree. Lithium was declared a strategic, non-concessionable mineral in Chile in 1979, meaning private operators must obtain a Special Lithium Operation Contract from the Chilean Ministry of Mining before any commercial activity. Quiborax's successful navigation of this framework positions El Águila as one of the most advanced privately led lithium initiatives in the country, the release states.

AC²ME Technology to Be Evaluated Against Real Industrial Materials at El Águila

Unlike conventional greenfield salar developments, El Águila targets lithium already contained within decades of accumulated industrial processing residues — an approach the company describes as circular mining. The CEOL framework expressly requires selective lithium extraction technologies, including Direct Lithium Extraction and innovative technological combinations. Rain's evaluation agreement provides a structured framework to test whether its AC²ME platform can deliver the recovery rates, selectivity, and economics the project requires. The current agreement is explicitly described as a scientific and technological evaluation only and does not constitute a commercial production agreement or joint venture.

Agreement Includes Pathway for Further Commercial Arrangements if Testing Succeeds

The release states that if technical results justify further development, the parties may subsequently negotiate separate agreements covering additional testing, pilot or commercial facilities, technology licensing, joint ventures, offtake, and other commercial arrangements. Rain's CEO Benjamin Hill noted in the announcement that El Águila offers a combination of an experienced operator, existing infrastructure, an identified lithium opportunity, and substantial regulatory progress. The company cautions that any commercial deployment remains subject to successful technical evaluation, applicable regulatory approvals, and separate definitive agreements.