But those cheers were tempered by fears that the incoming Trump administration will support the completion of the 1,172-mile pipeline
Fast forward to this week, and a flurry of new developments have emerged -- including renewed protests that have reportedly turned violent and a judge's ruling that gives another small victory to the protesters.
The latest clashes in North Dakota came as a group of protesters tried to reach a drill pad for the pipeline, the Morton County Sheriff's Department in North Dakota said.
At least 16 people have been arrested since Monday, facing charges such as criminal trespass, engaging in a riot, possession of marijuana, fleeing, assault on a peace officer and preventing arrest, authorities said. That means 603 people have been arrested at protest sites since August 10 last year.
This week, some protesters cut security wire, turned it into a weapon and threw it at law enforcement like a Frisbee, the sheriff's department said.
Protesters have said they believe law enforcement officers were the ones using unnecessary force, but noted that the situation was calming down by late Wednesday -- after a judge made a ruling against the pipeline's developer.
"It's cold. But things are calming down. Rubber bullets, mace, sirens, and razor wire ... typical night," Linda Black Elk
posted on Facebook.
"I think the cops are angry that they lost the appeal. They're being really mean."
Judge: Environmental study can continue
On Wednesday, a federal judge denied an effort by the developer, Dakota Access, LLC, to block the US Army Corps of Engineers from starting an environmental study on the impact if the pipeline's proposed route under Lake Oahe in North Dakota.
Construction of the pipeline, which stretches across four states, is complete except for the part under Lake Oahe, company spokeswoman Vicki Granado said.
Judge James E. Boasberg's decision effectively delays the final portion of the pipeline from being built.
Last month, the Army said it will not let the pipeline cross the federally administered reservoir on the Missouri River because the decision requires more analysis, including a deeper consideration of alternative routes, Assistant Secretary of the Army Jo-Ellen Darcy wrote
In her letter to the commander of the Army Corps of Engineers, she noted that the proposed route under Lake Oahe would be 0.5 miles upstream from the northern border of the Standing Rock Sioux Tribe's reservation.
"The Tribe relies on Lake Oahe for drinking water and irrigation ... and the Tribe retains water, hunting and fishing rights in the lake," Darcy wrote.
The Standing Rock Sioux Tribe applauded the news that the environmental study will proceed.
"We appreciate the time and effort it took to get us to this point; yet another small victory on the path to justice," the tribe said in a statement.
"It is, however, still not over. We still need your support. While the EIS (environmental impact study) is exactly what we called for, the final product must be stronger and more broad in scope."
Protests at confirmation hearing for EPA nominee
While protesters have celebrated a pair of small victories in the past month, there's a lingering concern that the new Trump administration will oppose their efforts.
Protests took place Wednesday outside the Senate confirmation hearing for Scott Pruitt, the President-elect's choice to lead the Environmental Protection Agency.
In an October interview with "Exploring Energy," Pruitt criticized those protesting the Dakota Access Pipeline as "hyper-environmentalists"
who are for "simply stopping all forms of fossil fuel energy."
Jason Miller, spokesman for President-elect Donald Trump's transition team, said last month that the pipeline is generally "something that we support construction of
The Trump administration will review the matter after the inauguration, Miller said.
In the meantime, the Midwest Alliance for Infrastructure Now
-- which supports the pipeline -- said it believes the pipeline will be completed under Trump's watch.
"We remain optimistic that the incoming Trump Administration will soon issue the final easement for the Dakota Access Pipeline and also demonstrate a willingness to support American infrastructure projects and the American jobs that go along with them," the group said.