The Honister Slate Mine donated £12,000 towards the Forestry Commission's Wild Ennerdale project, it has been revealed.
Money donated by the mine company helped fund the building of a bridge over the River Liza that will enable rare fish to spawn, while also improving access in the valley for those who like to go walking
The cash was raised by setting aside part of the proceeds from entrance fees paid by visitors to the mine, which produces the green slate seen in many Lake District buildings.
Honister's donation had been agreed by Mark Weir, the late owner of the slate mine, before he died in a helicopter crash earlier this year.
Mr Weir's plans to install a zipwire nearby sparked a fierce debate among the outdoor community, with strong views for and against, but the news of the donation may shed light on some of the other local activities and causes he had been involved with.
The River Liza runs into Ennerdale Water from the top of the valley and down through the Ennerdale Forest.
Visitors may include those attempting Alfred Wainwright's Coast-to-Coast route, which passes up its length.