Tesla supplier Piedmont Lithium has officially obtained a North Carolina state mining permit after posting a $1-million reclamation bond to develop an open-pit mine that would become one of the largest US sources of the key battery metal.

The North Carolina Department of Environmental Quality on Tuesday mailed the 16-page permit to Piedmont after a nearly three-year review process for the controversial mine, according to regulatory filings. The permit was provisionally awarded last month, pending the bond payment.

"We're pleased to have the final permit," Piedmont spokesperson Erin Sander told Reuters.

The permit, which includes detailed instructions for blasting, waste rock storage and multiple other areas, is transferable to a third party should Piedmont be sold, according to the regulatory filings.

The years-long opposition to Piedmont's project, which would become one of the few lithium-producing sites in the United States, illustrates broadening tensions as resistance to living near a mine clashes with the potential of electric vehicles (EVs) to mitigate climate change.

Piedmont must still obtain a zoning variance from officials in Gaston county, just outside Charlotte, for the more than $1-billion project. State regulators stressed that their permit "does not supersede or otherwise affect or prevent the enforcement of any zoning regulation duly adopted by any incorporated city or county."

Piedmont has not yet filed for a zoning variance, and Gaston county officials told Reuters last month they would not begin to consider one until at least July.

The company, which is also working on three other lithium projects, must still obtain financing for the North Carolina mine and processing facilities, as well as state air quality and wastewater permits. Piedmont is expected to provide a financing update when it releases quarterly results on Thursday.