Spain-incorporated Tecpetrol Investments has revealed it approached Canada’s Alpha Lithium with a C$241 million ($178m) all-cash offer, which the target reportedly “refused to consider.”

Tecpetrol said the bid for Alpha Lithium, which is active in the Tolilar and Hombre Muerto salt flats in Argentina, valued each of the Canadian firm’s shares at C$1.24 — a 13% premium to the closing price on May 12.

The company, part of the Techint Group, said it sent the offer letter to Alpha Lithium’s CEO on May 15. It added that Alpha Lithium refused to consider the proposal and did not engage in discussions between advisors.

The Vancouver-based lithium firm refuted Tecpetrol’s statement by saying it had conducted a review and assessment of the proposal, which it determined it to be “opportunistic” and “not in the best interests” of Alpha or its shareholders.

“The offer, which was non-binding and subject to due diligence, included a request for Alpha to enter into a binding 30 day exclusivity agreement with Tecpetrol, which would preclude Alpha from engaging with interested third parties who appropriately value the company,” it said in the statement.

Tecpetrol said it remains prepared to engage with Alpha “immediately” and improve its offer.

Alpha Lithium said earlier this month that construction of its 120 tonne-per-annum lithium carbonate pilot plant in Argentina was nearing completion, with production to begin this summer.

The objective of the pilot plant is to demonstrate Alpha’s Direct Lithium Extraction (DLE) laboratory results.

The facility has the potential to utilize brine from both the Tolillar Salar and  the Hombre Muerto projects.