Dave Harris-Jones aims to carry a 20kg sack of flour up 815m – the equivalent of the height of Cheviot – on Monday.
He will take on the challenge by carrying the sack from the mill basement to the upper floor 136 times or 4,352 steps.
He is doing it to raise funds for Northumberland National Park Mountain Rescue Team.
He explained: “I am doing this event climbing the equivalent of the height of Cheviot carrying a 20kg sack of flour whilst also running the mill at Heatherslaw to keep making flour for local shops during the COVID crisis.
“The inspiration for this has come from my good friend Tom Hammill who loves the mountains and the mill at Heatherslaw.
“I also hope to make sure we maintain our awareness of staying off the mountains during the COVID crisis so as to protect our frontline services.”
Dave is currently training to become a full team member of the mountain rescue team which has recently been attending wild fires in the Simonside Hills, near Rothbury.
He said: “Many of my colleagues in mountain rescue are frontline NHS workers, we really need people to stick to the rules and not go on the hills and so reduce the need for our services as a team. The hills will still be there once we have given Covid the boot.”
To donate, visit www.justgiving.com/fundraising/Dave-Harris-Jones