Nova Scotia has approved an application by AltaGas Ltd. to proceed with its Alton natural gas storage project, but some critics — including the nearest Mi'kmaq band — remain unconvinced it is safe for the environment.

"Most likely we are going to be down there protesting. Most likely we are going to fight the fight," Sipekne'katik Chief Rufus Copage tells CBC News.

Nova Scotia's decision to press pause in the fall of 2014 on the project by withholding required permits was designed to avoid that scenario.

AltaGas wants to store natural gas in three underground salt caverns near Stewiacke, N.S. Environmental concerns focused on the release of salty water from drilling the underground caverns into the Shubenacadie River system.

Mi'kmaq chiefs had complained they had not been adequately consulted.

No veto for Mi'kmaq

Nova Scotia's Liberal government said Thursday that after 18 months it has satisfied its obligation to consult with the First Nations and modifications to the project were made.

"The duty to consult does not include a veto option for First Nations," provincial Energy Minister Michel Samson said Thursday in Halifax.

"Government believes the project is safe and does not threaten the environment."

The permits allow the company to operate a brine storage pond and lease Crown lands for the project.

Nova Scotia Energy Minister Michel Samson announced Thursday that the province has approved a permit by AltaGas to operate a natural gas storage facility in Stewiacke, N.S. (CBC)

The company will be required to stop releasing brine for 24 days during peak striped bass spawning periods. That's an increase from the 14 days previously required.

There will also be more detailed and frequent monitoring of the project impacts.

Art Redden, a striped bass angler who lives in the area, does not trust the province.

"I don't want to see the equivalent of 50 tandem truckloads of salt go into that river everyday for the next three years," Redden said Thursday.

Jay Breton from the province's Environment Department downplayed the impact.

"Under the approval, the salinity levels of the river have to meet normal background levels," Breton said.

Mixed signals from Mi'kmaq

The Mi'kmaq community is sending mixed signals on the project.

The Mi'kmaq Rights Initiative, which represents the Assembly of Nova Scotia Mi'kmaq Chiefs in negotiations with the province, has endorsed the outcome.

"We can say that given the project design, the assessment of impacts and the increased monitoring, the project should not have significant impacts to the environment," the assembly said in a January 2016 update on the Alton project.

Speaking on behalf of the Assembly of Chiefs, Paul Prosper said Thursday the review was extensive.

"There have been some accommodations made with respect to project design, monitoring, shutdown duration and things like that," Prosper tells CBC News.

"But that is not to say the consultation process has ended. It continues on the pipeline element of it."

However, the chief of Sipekne'katik said the band does not feel it was fully included in the consultation process. It asked the province to delay approvals while it holds a referendum.

"It's hard for us to say go forward with it if our community members don't know what's going on," Copage said.

"This process expects us to allow proponents to come to our unceeded territory and propose to do what they wish in the interest of economics," he said in a statement. "Our grassroots people have no voice."

The Sipekne'katik band council moved Thursday to formally withdraw from the Assembly of Nova Scotia Mi'kmaq Chiefs.

AltaGas proceeding

AltaGas, headquartered in Calgary, said the project will save natural gas consumers $17 million a year by maintaining a supply during winter months when prices typically spike.

AltaGas spokesperson Jess Nieukerk said the company still hopes to meet an in-service target of 2018, but acknowledged that could be moved to 2019.

"We welcome the issuing of the permits. We will continue to engage with government, residents and the Mi'kmaq of Nova Scotia," Nieukerk said in an interview from Calgary.