PNC Bank will substantially cut its financing of coal companies that practice mountaintop-removal mining, according to a new policy included in a bank report released Monday.

The move is seen as a victory by anti-coal activists as PNC joins a growing group of banks that formerly loaned collective billions to coal extraction companies and say they are cutting back on the practice.

The changes are "driven by environmental and health concerns, as well as our risk appetite," PNC said in its 2015 Corporate Responsibility Report.

The bank will not extend credit to coal producers with 25 percent or more of their production from mountaintop-removal mining, the report says. Its previous policy excluded only producers for which mountaintop-removal mining was the majority of production.

PNC also will not finance individual mountaintop-removal mining projects, continuing a policy implemented in 2010.

"This is the victory we were hoping for. We think this change is going to . . . mean a real difference," said Eileen Flanagan, a board member of the Earth Quaker Action Team, a Philadelphia-based group that has lobbied PNC about the issue for the last five years.

Mountaintop-removal coal mining is the practice of blasting off the tops of mountains to expose coal seams that can then be mined. In the process, rubble and waste fills surrounding valleys.

The practice often contaminates streams, hurts wildlife, and likely causes human health problems, scientists say.

The practice has destroyed or damaged more than one million acres of forest and almost 2,000 miles of streams in Appalachia, according to a 2009 Yale University study.

Pennsylvania-based PNC has lent millions of dollars to companies that do mountaintop removal coal mining, an estimated $210.5 million in 2013 and $687.5 million in 2012, according to data from Bloomberg and compiled by the Rainforest Action Network, a nonprofit environmental group.

PNC has funded some of the top coal producers, including Arch Coal and Alpha Natural Resources, according to the data.

PNC is not alone among major banks. In recent years, some, such as JP Morgan Chase and Wells Fargo, have made commitments to reducing their exposure to the companies amid activist pressure.

"A decision by PNC on this issue [is] part of a growing trend of major Wall Street and European banks pulling away from financing mountaintop-removal mining," said Ben Collins, senior research and policy campaigner at Rainforest Action Network.

Flanagan attributed PNC's move largely to the group's pressure.

"We feel that we have bent the will of the seventh-largest bank," she said.

Supporters of Earth Quaker Action Team have removed more than $3.5 million from the bank by closing their accounts in protest, based on figures reported to Earth Quaker Action Team, Flanagan said.

PNC spokesman Fred Solomon would not say whether the activism had any effect. "We wouldn't comment on any third party," he said.