A long-running legal battle over a mining project near William's Lake in B.C's southern Interior continues in court today.

The Tsilhqot'in Nation is seeking an injunction from the B.C. Court of Appeal against a drilling permit issued to Taseko Mines Ltd.

Taseko's proposed New Prosperity Mine, located 125 kilometres southwest of Williams Lake was approved for development by the provincial government in 2010 and issued a drilling permit in 2017 for the company to collect geotechnical information.

The Tsilhqot'in Nation is trying to protect Fish Lake — called Teztan Biny in Tsilhqot'in — which they say will be harmed by the project.

On March 1, the B.C. Court of Appeal issued a judgment recognizing the Teztan Biny area as an active cultural school for the Tsilhqot'in, a resting place for ancestors, a site for spiritual and ceremonial activities and "a place of unique and special significance for the Tsilhqot'in cultural identity and heritage."

But the court gave permission for the project to move ahead despite that recognition.

Fish Lake in B.C.'s southern Interior is part of a watershed system at the centre of a proposed Taseko Mines' Prosperity Mine project. (CBC)

An injunction could halt the project while the Tsilhqot'in applies to the Supreme Court of Canada for leave to appeal the March 1 judgement.

The Federal Government has already rejected the project proposal twice — in 2010 and 2014. Both times, the mine was rejected, in part, because of its impact on Tsilhqot'in rights and the risk it poses to fish and fish habitats.

According to a statement from the Tsilhqot'in Nation, Teztan Biny is one of the province's most productive wild trout lakes.

Taseko has been trying to build the project for decades. The company began proposing the project to the federal and provincial governments in 1995.

With files from The Canadian Press