Tests by Township of Langley staff have found a Walnut Grove mineral processing plant was over the maximum allowed noise levels.
The tests were carried out in response to complaints by several residents living in the area of the Lhoist plant near 203 Street and 102B Avenue, who filed a petition with the Township.
The residents told the Township the noise from the plant was a nuisance.
“The noise emanating from the kiln fan and other equipment can be heard day and night,” the petition stated.
An unsigned memo to Township council by the community development division said noise measurements were carried out at eight locations near the plant on the evening of Aug. 24.
The tests showed levels were roughly double the maximum allowed limit of 60 decibels (between 10 p.m. and 7 a.m.) at four sites, which measured between 67 and 70 decibels.
According to an online comparison chart posted by Purdue university, 70 decibels is twice as loud as 60 decibels.
At 60 decibels, the chart rates noise as “fairly quiet.”
That is defined as the level of a conversation in a restaurant, background music or an air conditioning unit at a distance of 100 feet.
At 70 decibels, noise is considered equal to radio and television audio or a vacuum cleaner.
Two sites about a block away from the Lhoist plant measured less than 40 decibels.
The Purdue chart calls that level the “lowest limit of urban ambient sound,” describing it as the equivalent of a library or bird call.
The Aug. 27 memo to council suggested it was the type of noise, not the volume that is the problem, pointing to the “harmonic sound” produced by the kiln.
Staff “suspect any works done to bring the noise levels to 60 DB after 10 p.m. will not change the sound being complained about …” the memo said.
More tests may be needed and the company may have to hire a sound consultant to get the noise levels below the nighttime limit, the memo added.
The website for the Lhoist Group, describes the owner of the Walnut Grove plant as a “global leader in lime, dolime and minerals” headquartered in Belgium, with 6,000 employees in 25 countries with more than 90 facilities.
A query to Lhoist headquarters from The Times had not produced a response by press time.
A statement on the company website says the Lhoist Group “attaches great importance to respecting both the people and the environment surrounding the sites where we mine and process minerals. Our objective is to always behave like good citizens.
“We understand that we must embrace our responsibility to respect the environment and the communities in the vicinities of our operations.”