"We are very pleased with the decision regarding the rehabilitation and restoration plan for the Rose lithium-tantalum project, which is a necessary step toward securing the mining lease," Critical's CEO Jean-Sebastien Lavallee said.

The final remaining step in the Quebec-based project's approval is the completion of the provincial permitting process, which runs parallel to the federal process, the company noted.

Meanwhile, in regard to Critical's pilot testing, the company said two critical steps from the process were the conversion from alpha spodumene to beta spodumene where the work achieved a 98% conversion rate and the separation of the lithium hydroxide from the calcined spodumene by soda-leaching that saw a 98% efficiency as well as a conversion to lithium hydroxide of 96% efficiency.

"Following this successful lithium hydroxide process optimization campaign, Critical Elements will finalize its feasibility study for a lithium hydroxide conversion facility," the company said.

Critical noted that as the study is still underway, it cannot confirm whether the hydroxide chemical plant will ever be implemented or that it will form part of the Rose project.

A 2017 feasibility study on Rose projected an IRR for the project of 34.9% after tax, with a NPV of C$726 million (US$566.32 million) at an 8% discount rate.

The company's share price recovered 11% in value on May 17, climbing to C$1.43. It has seen a 52-week high/low of C$1.98/C$1.13.

Critical has a market capitalization of C$294.85 million.