WASHINGTON — Democratic lawmakers, seeking to prevent another mine disaster like the April explosion that killed 29 workers in West Virginia, proposed sweeping new legislation Tuesday that would make it easier to shut down mines with poor safety records.

The bill — to be introduced in the House this week — would also boost penalties for serious violations, grant mine regulators the power to subpoena documents and testimony, and offer greater protection to whistleblowers who report safety problems. The Senate is expected to take up a similar measure soon.

Leaders of House and Senate committees that oversee mine safety said the measure is needed to fix a badly flawed system that came to light after the accident at the Upper Big Branch mine in Montcoal — the nation’s worst mining accident in four decades.

“Mine operators who callously and repeatedly put their workers in danger must be held accountable,” said Rep. George Miller, chair of the House Education and Labor Committee.

Democratic leaders have said they want to pass the legislation by year’s end.

Rep. Nick Rahall, D-W.Va., joined House and Senate leaders in unveiling the comprehensive reforms.

“As I stood vigil with the families and friends of the miners who lost their lives at Upper Big Branch, I committed to doing all that I could to help ensure that steps were taken to prevent a recurrence of this type of mine disaster,” Rahall said.

“I am encouraged that there are discussions to name this legislation after Sen. Robert C. Byrd, my mentor and the great champion of miners. Given his lifetime of accomplishments on behalf of miners, it seems an appropriate thing to do,” Rahall added.

The reforms would address many of the issues that have surfaced as a result of the Upper Big Branch explosion, as well as additional serious mine health and safety concerns raised by miners and their families, Rahall’s office said.

“This legislation has been crafted, in large measure, to target and rein in the worst of the mine safety violators, while also providing for independent investigations,” Rahall said. “I fully intend to keep drawing on the experiences of miners, their families and coal industry members to fine tune this bill to ensure that coal miners have safer, healthier workplaces while they continue their vital work providing for America’s energy needs.”

Mine industry officials who were still reviewing the details said they expect some tinkering, but warned lawmakers against going too far.

“While it may be necessary to supplement the tools they have, they have to implement tools they already have,” said Luke Popovich, a spokesman for the National Mining Association.

Some Republicans expressed disappointment that Democrats did not work with them in crafting the plan. Sens. Mike Enzi, R-Wyo., and Johnny Isakson, R-Ga., said they wanted to see the kind of bipartisan approach that happened the last time Congress passed comprehensive changes to mine laws following the 2006 Sago mine disaster in West Virginia.

“Instead of pursuing that productive approach, Democrats have chosen to introduce a sweeping piece of legislation that affects every business in this country and only amplifies the adversarial role of (government regulators) without increasing safety,” the senators said in a statement.

Under the current system, mine companies can file lengthy legal appeals that can last months or years, delaying the finding of a pattern of violation that could lead to stricter oversight. That system — and the massive case backlog it spawned — allowed the Upper Big Branch mine to avoid more scrutiny, despite the fact it was repeatedly cited for ventilation and dust problems in the months leading up to the blast.

The bill would end those delays and develop a better system for the Mine Safety and Health Administration to identify mines with a pattern of serious violations. If a mine meets the new criteria, miners would be withdrawn and the mine reopened for a probationary period with stepped up inspections. The mine would have to meet safety benchmarks for one year.

The agency would offer more guidance to help troubled mines get back on track, such as additional training or creation of special health and safety programs.

MSHA could also seek a court order to close a mine due to continuing health and safety problems and require increased rock dusting to prevent coal dust explosions like the kind investigators believe occurred at Upper Big Branch.

The bill would grant miners the right to refuse to work in unsafe conditions and increase protections for workers who complain about unsafe conditions. Miners would not lose pay if their mine is closed for safety reasons.