The announcement by the company comes amid a phalanx of opposition by some First Nations and environmental groups during public hearings.
But the agreements prove there is greater support for the almost 1,200-kilometre pipeline, said Enbridge spokesman Paul Stanway.
"It's a good place for us to start in demonstrating that there is aboriginal support for Northern Gateway," Stanway said. "It's not 100 per cent, but neither is it the wall of opposition that our opponents sometimes claim."
The 10 per cent equity ownership for the First Nations who signed the deal will give them about $280 million over 30 years. They would see cash flow starting in the first year of the pipeline's operation.
The names of the aboriginal partners won't be released because of contractual agreements, but Stanway said the support is split about evenly between Alberta and B.C. First Nations.
There are 45 First Nations along the pipeline, but Stanway wouldn't give a final figure on how many signed on.
He said the pipeline discussion may appear polarized from the outside, but the majority of people are in the middle on the issue.
"Some of those are willing to partner with us. That's not to say they still don't have some concerns. They want to make sure that we build and operate the pipeline as safety as possible."
Stanway said one of the advantages for First Nations who have signed the equity-sharing agreement is that they'll have more clout when it comes to decisions that are made in operating Northern Gateway.
Wilf Adam of the Lake Babine First Nation in Burns Lake, B.C., said he refused to sign the equity agreement because Enbridge was unwilling to release more details in the contract.
"I'd been asking for the financial figures and I'd been asking about the employment. They said there would be a lot of employment."
Adam said it appeared to him that there would be few jobs available for his people.
"You're not going to get a lot of jobs out of one pump house, which they said they were willing to put on our land. It would probably create fewer than five jobs."
Adam said there was a flurry of emails and phone calls from Enbridge officials after the company moved the deadline for signing the equity agreement up to May 31.
"They tried their best to sign us up, but I will not sign that agreement."
Adam said he couldn't see how it was going to be good for his people, but he figured that possibly four out of the six bands in his areas signed the equity-sharing agreement.
The proposed $5.5-billion pipeline would run from Bruderheim, Alta. to Kitimat B.C., moving about 525,000 barrels of oil per day to Kitimat for export.
The public hearings have been marred by protests by First Nations and others groups. In April, hearings in Bella Bella, B.C., were put on hold amid safety concerns raised by the panel members from the federally-appointed review board.
The public hearing process is nearly at the midway point, and in September formal hearings will begin where expert witnesses will testify under oath to the review panel.
Stanway said the public hearing process has been frustrating for the company because Enbridge has only been an observer.
He said they often have the answers to many questions people are asking, but have been unable to answer them in the public process.
"But we do get to present our case in detail in the fall."
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