As utility regulators reconvene Tuesday to determine the fate of Enbridge’s controversial oil-pipeline proposal, the parties are still at work making their cases.

Ads and opinion pieces ran in newspapers, and Enbridge announced more details about its recent deal-sweetening commitments.

Meanwhile, Gov. Mark Dayton has been meeting privately with Minnesota tribal leaders and law enforcement agencies.

The Minnesota Public Utilities Commission (PUC) started its final hearings on a Line 3 replacement last week, and is expected by Friday to decide whether to grant a permit for the $2.6 billion project.

Calgary, Alberta-based Enbridge wants to replace its Line 3, an aging and corroding pipeline that runs across northern Minnesota to the company’s terminal in Superior, Wis. Line 3 is one of six Enbridge pipelines in the same corridor that transport Canadian oil to Midwestern markets, as well as to the Gulf Coast.

The current Line 3 operates at only 51 percent capacity due to safety concerns. Enbridge said a new pipeline, which would restore full oil flow to 760,000 barrels per day, is a necessary safety upgrade.

Environmentalists and several American Indian tribes oppose the new pipeline, saying it will spur climate change and open a new region of lakes, rivers and wild rice waters to degradation from possible oil spills.

Enbridge’s proposed new Line 3 would run along its current route to Clearbrook, Minn., then jog south to Park Rapids before heading east to Superior.

In a regulatory filing late Friday, Enbridge answered several questions raised by PUC members during the hearing last week, including about decommissioning the current pipeline.

The abandonment of old Line 3 — which will occur if the PUC approves a new pipeline — has been a contentious issue, and Enbridge unveiled a new twist.

The company has long said it plans to drain and clean old Line 3, and then seal it off into sections to avoid long-term environmental problems — called “decommissioning-in-place.” Landowners who host old Line 3 — and allow it to be kept in the ground — will be compensated, subject to negotiations with the company, Enbridge said in the filing.

The company said it expects the payments to be “roughly equivalent” to those made to Canadian landowners who opted to keep old pipe in the ground. Enbridge is also building a new Line 3 in Canada. The company declined to be more specific on the payments.

The company earlier this month committed to removing the old pipe for free if that’s what landowners wanted. However, Enbridge wrote in the filing that in some cases, removing the old pipe may not always be technically feasible.

Enbridge also Friday amplified a commitment made earlier this month to allot at least $100 million in work on a new Line 3 to Indian subcontractors or employees. The company said it expects to achieve this target within three years of when the new Line 3 would go into service.

The work would include construction and decommissioning. “While preference will be given to Minnesota-based tribal members and businesses, non-Minnesota-based tribal members and businesses are included in the $100 million target,” Enbridge said in the Friday filing.

Minnesota’s largest Ojibwe tribes have largely opposed any new pipeline. However, at last week’s PUC meetings, it became clear that the Leech Lake Band of Ojibwe would prefer a new Line 3 over continued use of the old pipeline, which runs across its reservation. Tribal representatives said the old pipeline poses a bigger environmental threat to the band than a new pipeline.

The current Line 3 also runs through the reservation of the Fond du Lac Band of Lake Superior Chippewa, which has been opposed to a new pipeline of any kind. Under Enbridge’s proposal, the new Line 3 wouldn’t cross any reservations, though it would traverse land upon which the Ojibwe claim treaty rights to hunt, fish and gather.

On Friday, Dayton met with the chairmen of the Leech Lake and Fond du Lac bands, in Bemidji and Cloquet respectively. Dayton also met at the Minnesota National Guard’s Camp Ripley in Little Falls with a group of sheriffs from counties that could be affected by protests over a new Line 3.

On Thursday, Dayton spoke by phone with the Canadian ambassador to the United States. He also met with Winona LaDuke, head of the indigenous environmental activist group Honor the Earth, which opposes a new pipeline and has called for large protests if new a Line 3 is approved.

“He’s deeply concerned about the proposed pipeline, and he realizes the gravity of this situation for Minnesota, and not just for the environment, but civil society,” LaDuke said.

Dayton’s office said the governor would be meeting with proponents and opponents of Line 3 into this week, declining to comment further.