Here’s the website the lumberyard has set up for sharing information about the hum.
via press release (bolding below is mine)
R.A. YANCEY LUMBER COMPANY RESPONDS TO NOISE DISTURBANCES IN CROZET
CROZET, VA (Oct. 23, 2018) – R.A. Yancey Lumber Company (Yancey Lumber) announced today that lumber production will scale back significantly beginning this evening in response to the noise disturbances reported by neighborhoods surrounding the mill. The noise is stemming from the exhaust stack of the boiler for the company’s kilns. The company has ordered a custom-made sound muffler for the stack as a solution; however, it is estimated it will take two weeks to manufacture and ship. Until the muffler is installed, the kiln will run in “pilot light mode,” allowing the boiler to maintain enough heat at night to power up and treat lumber during the day, but halting all lumber curing operations at night.
Local citizens began reporting noise disturbances in neighboring communities last month. Several companies – Yancey and Dominion, among others – were approached about the source of the noise. At that time, Yancey Lumber did not believe the mill was the source, as no new equipment had been installed. A kiln was refurbished in August, but that kiln had been used since 1992 with no prior complaints. Given the community’s concerns, Yancey Lumber hired Acentech, an acoustical consulting firm, to investigate and measure sound levels at the mill and properties of several neighbors who had reported disturbances.
On Wednesday, Oct. 17, Acentech determined that the noise’s origin was the Yancey boiler’s exhaust stack. The company immediately began attempting to source the right equipment to muffle or cancel the noise. It has ordered a “silencer” insert that will be custom built on an expedited basis. In the meantime, the company has been making adjustments to the drive frequency of the boiler fan to reduce its speed; however, based on the reports, the reduction did not have the intended effect.
The Yancey family has owned and operated the mill in Crozet since 1949. “We are committed to being a good neighbor and community member,” said President Donnie Rose. “We are extremely sorry for the disturbances and sleepless nights the kiln has caused. We want the community to know that we’re doing everything we can to keep that from happening again.”