The management of the Honister Slate Mine Company have sent an email to supporters urging them to write in to the Lake District National Park Authority Planning Board expressing their backing as soon as they can.
"We have been advised by the Lake District National Park Authority Planning Board that letters or emails in support of our new application should be submitted immediately," the firm said.
The plan is a revised version of the original zipwire proposal that was turned down by national park planners last year.
Many in the outdoor community support the idea, but Friends of the Lake District argued the wire would interfere with those who want to go walking
on a popular path up Fleetwith Pike and onto Haystacks.
Some walkers undoubtedly benefit from the presence of the Honister Slate Mine, which won the Cumbria Tourism Awards best attraction prize in 2011.
Those staying at the adjacent Honister Youth Hostel as a base for exploring the nearby mountains have their electricity supplied by a generator shared with the mine.