Some Senate Democrats are planning to block or slow down legislation as Republicans try to whittle down what’s left of their to-do list for the 114th Congress this week.

Majority Leader Mitch McConnell said on the floor Monday that he plans to complete work on a spending measure to keep the government funded and a conference report authorizing defense programs. McConnell added that work continues on water infrastructure legislation and an energy policy bill.

Passing all of that by Friday would require unanimous consent requests to cut through the chamber’s time requirements. But four Democrats served notice Monday that they would block such requests until there is action relating to health care and pensions for coal miners. 

But slowing down the process will likely not affect the outcome of the major bills. It is also possible that senators would only delay action for a few days on those major bills, since there is a maximum of 30 hours of consideration after senators vote to end debate on the legislation. In other words, after cloture is invoked, the senators can run out the 30-hour clock, but will not be able to delay the legislation any longer. However, they could block minor pieces of legislation that are typically passed by unanimous consent. 

Sens. Joe Manchin III of West Virginia, Sherrod Brown of Ohio, Bob Casey of Pennsylvania and Mark Warner of Virginia said they hope to force leadership to address an anticipated shortfall in benefits to retired mine workers. The senators said more than 16,000 retired miners could lose their health care by the end of the year if Congress does not act.

The senators want to transfer money from the Abandoned Mine Lands fund, which is used to clean up and reclaim abandoned open-pit mines, to the United Mine Workers of America 1974 Pension Plan, a public-private retirement fund for miners that is set to become insolvent.

“For several months, we have joined thousands of our states’ retired coal miners and their families to call for a vote on this bipartisan, paid-for bill. And for several months those calls have gone unanswered,” the senators said in a joint statement. “These miners cannot wait another day and it’s up to us to protect what they’ve earned for a lifetime of dangerous, backbreaking work.”

[Coal State Lawmakers Seek to Link Puerto Rico to Miner Pensions]

California Democratic Sen. Barbara Boxer is also threatening to block a water infrastructure bill over a last-minute provision that was added to address the ongoing drought in the Golden State. Boxer argued the provision would compromise the Endangered Species Act, potentially contaminate drinking water in California, and take away Congress’ power to approve dams.

Boxer said she has enough Democrats on her side to slow the bill down. 

“I don’t personally think Sen. McConnell is going to bring this up because he knows it’s going to take days and days and days and days because I have enough people who are going to help me,” Boxer told reporters Monday. “If he does, then we’ll be here through Christmas and New Year’s Eve.”

“I’ll just let the clock run out,” she said. “Now, maybe there’s a way they could shut me down, tie me up in my office. You never know. Stranger things have happened in my life. But given what I know, I think it would be hard.”

Boxer’s fellow California senator, Democrat Dianne Feinstein, supports the provision and said it was “the best we can do.” She said the provision does not negatively affect the environment or wildlife, and authorizes critical projects that would produce water for the state.

“If we don’t move now, we run the real risk of legislation that opens up the Endangered Species Act in the future, when Congress will again be under Republican control, this time backed by a [Donald] Trump administration,” Feinstein said.

[Water Bill a Better Vehicle to Help Flint, Ryan Says]

The infrastructure bill, known as the Water Resources Development Act, also included language that would authorize aid for Flint, Michigan, which has been dealing with a lead contamination crisis. But Boxer said if the WRDA does not pass, aid for Flint would still be attached to the resolution funding the government, which faces a Friday deadline.

Democratic Sen. Gary Peters of Michigan said the developments are “highly concerning” and blamed House Republican for jeopardizing a bipartisan effort.

“I remain focused on holding Republicans to their commitment to complete a Flint aid package before Congress adjourns — even if that means using the end of year spending bill as a vehicle,” Peters said.

Contact Bowman at bridgetbowman@rollcall.com and follow her on Twitter @bridgetbhc.