The President has said both actions were taken to harness American energy and create jobs. Native communities fear the changes will come at their expense.
"The Nation is concerned that coal mining near the Northern Cheyenne Indian Reservation will impact our pristine air and water quality, will adversely affect our sacred cultural properties and traditional spiritual practices and ultimately destroy the traditional way of life that the Nation has fought to preserve for centuries," said Jace Killsback, president of the Northern Cheyenne.
Environmental groups have been raising money and preparing to battle Trump since his election, and the fight over coal is expected to be the first of many.
The President already has moved on a campaign promise to dismantle parts of the federal Government, with recent proposals to dramatically cut funding for the Environmental Protection Agency and the Department of Interior, the nation's steward for public lands.
"No one voted to pollute our public lands, air or drinking water in the last election, yet the Trump Administration is doing the bidding of powerful polluters as nearly its first order of business," Jenny Harbine, a lead attorney for the activist group Earthjustice, said on Thursday. "Our legal system remains an important backstop against the abuses of power we've witnessed over the course of the past two months."
The coalition may have company in its legal challenge.
Several governors and attorneys general have indicated a willingness to take the Trump Administration to court over the new Executive Order and other environmental policies. California's Democratic Governor Jerry Brown said in an interview that he was prepared to sue if the EPA revokes the waiver it granted his state in 2012 to set more stringent fuel-efficiency standards for cars and light trucks built for model years 2022 to 2025.
Trump recently announced that the agency would revisit the federal carbon standards for that fleet, prompting California to announce it would press ahead with its own rule.
"I fought the Bush Administration as California's attorney general and will continue defending the California law," Brown said, adding that climate change ranks as "an existential threat" that must be addressed. "Not out of any political position, but in recognition that the world is at risk and that the lives of real people are endangered."
Washington Governor Jay Inslee, also a Democrat,, who successfully challenged the Administration's first immigration Executive Order, said he and his state's attorney general are assessing whether to return to court in light of the new Executive Order on climate. "We're looking at some litigation options," he said.
At a recent conference, Montana Governor Steve Bullock, a Democrat, emphasised the importance of preserving public lands. "As Governor of a state with millions of acres of public land," he said, "I will not stand idly by if Congress or other outside special interests try to erode the birthright of all Americans."
But Trump and Interior Secretary Ryan Zinke have powerful allies, including Utah's Republican Governor Gary Herbert, whose office sued over the Obama Administration's Clean Power Plan to regulate greenhouse gases and ripped the rule that led to a moratorium on coal leases.
"Utah and many public-land and energy-producing states think that the Clean Power Plan was a significant overreach. It was really designed to kill off carbon-based fuels and particularly coal," he said recently. "The standards that they were trying to put in place, there is not even technology that allows you to meet those standards."
Under the National Environmental Policy Act, or NEPA, established in 1970, conservationists and other organisations can fight any government attempt to take administrative action without following proper administrative procedures. "These regulations are binding on all federal agencies," according to a NEPA fact sheet on the EPA's website.
Following Trump's action, Zinke announced on Thursday that he signed two "secretarial orders to advance American energy independence". One was to "foster responsible development of coal, oil, gas and renewable energy on federal and tribal lands".
The lengthy statement did not mention NEPA or the environmental study it requires.
In Montana, that's where the coalition lawsuit filed in US District Court in Great Falls took aim. "In repealing the moratorium ... the Secretary of the Interior, Department of Interior and Bureau of Land Management opened the door to new coal leasing and its attendant consequences without first performing an environmental review."
Under the Obama Administration, Interior worked for more than a year to evaluate the impact of coal mining and to determine if the benefit was worth the environmental harm. With US power plants using less coal, companies have laid off workers and entered into bankruptcy proceedings. And with abundant coal reserves expected to last two decades even without new mining, the department decided on a moratorium.
"The moratorium was a common-sense policy move to fix our federal coal programme, and Trump's actions likely mean that programme will stay broken," Shannon Hughes, who works in the climate and energy programme at WildEarth Guardians, said in a statement.
