The Delaware County Board of Supervisors has given initial approval to rezoning land just west of Hopkinton for a bitcoin mining company, but will require a new type of cooling system.
County Supervisor Shirley Helmrichs said the land which is currently in an agricultural zone would be reclassified for light industrial use by Compass Mining. “They’re like storage trainers with fans in them and my brain really doesn’t comprehend bitcoin mining,” Helmrichs said, “but it’s to grab a series of numbers and there’s only about 20% of them left in the world and that’s what bitcoin mining is.”
Compass Mining acquired five acres near Hopkinton about two years ago and began operating at the site in January of 2025. Helmrichs said the company has agreed to address noise concerns, but the county will hire an independent consultant to conduct a noise study to confirm that improvements have been made. “On different days when the wind was out of the south, it was louder…and that would go up to Lime Creek Feeders (near Coggon) and would affect his cattle kind like stray voltage did back in the day,” Helmrichs said. “If it’s covered with this building over it — it’s called the ‘miner building,’ then that would control that noise because you wouldn’t hear the fans.”
About dozen Delaware County residents attended a public hearing earlier this week and expressed concern about the loss of farmland. They also raised questions about the bitcoin operation’s use of electricity. Helmrichs says there’s been no rate increase due to the bitcoin mine’s power demands. “The CEO has said there will never be a power surge from it,” Helmrichs said. “…They have a separate REC account.” The company has an Electric Service Agreement with Eastern Iowa Rural Electric Cooperative in Wilton.
Helmrichs said the county will require Compass Mining to switch to a system that uses a combination of water and glycol, an anti-freeze, that will circulate to cool the facility. The Delaware County Board of Supervisors must vote at a future meeting on the rezoning proposal, along the other stipulations. There’s no state database showing where or how many bitcoin mines are operating in Iowa.
(By Janelle Tucker, KMCH, Manchester)
