Milling Out Asbestos in Canada

“There are some roads in Quebec, usually those with very heavy truck traffic, where they’ve put asbestos in the roads.” — Denis Lussier

According to the International Agency for Research on Cancer, modern industrial use of asbestos dates back to 1880 when the Quebec chrysotile fields began to be exploited. In the following decades, the use of asbestos grew until new research on the safety of asbestos resulted in its rapid decline between 1970 and 1990. As a result, writes Quebec-based environmental services specialists Lab’eau-air-sol, “Quebec found itself with an abundance of chrysotile residues and no buyers.”

“After years of discussion and laboratory testing, the use of chrysotile in bitumen became common practice [in Quebec] in the ‘90s,” Lab’eau-air-sol continues, adding that chrysotile asbestos is a “highly resistant fibrous material, enabling significant reinforcement of bitumen matrix,” while the mixture’s non-friability makes its use in roads relatively safe for road users. However, Lab’eau-air-sol writes, there remains significant exposure risk when these roads are demolished, resulting in special measures to protect workers and increased removal costs than conventional asphalt.

According to Lussier, ACI has completed 50 asbestos-coated asphalt projects since 2010 and is one of a handful of companies in Quebec equipped to work with asbestos-coated asphalt. However, he added, “Asbestos projects represent a small percentage of annual planning and will continue to decrease because the Ministry of Transport removed asbestos-containing mixes from its standards in 2011.”

As companies like ACI are brought in to mill the remaining pavements containing asbestos–“usually those with very heavy truck traffic,” Lussier said–the company must follow all safety procedures and best practices. Lussier said there are two ways to handle these types of roads: stabilization and dry method. “When choosing the stabilization approach, a bitumen emulsion is introduced into the leveled layers of the surface, allowing asbestos particles to bind together,” Lussier said. “This process helps prevent the release of hazardous dust or fumes.” In the case of the dry method, he added, the pavement material is gathered, enclosed in large stitched bags, and then disposed of at a landfill site authorized by the Ministry of Sustainable Development, Environment, and the Fight Against Climate Change.

“The second method can be very expensive, so we prefer the first method, but ultimately the choice is up to the Transportation Ministry,” Lussier said. ACI has retrofitted one of its milling machines to handle the first method. When the company must utilize the second method, it would prefer to use its BOMAG milling machine in order to benefit from the ION DUST SHIELD, given that the asbestos particles are also quite fine. However, the machine isn’t quite large enough to make sense on the types of roads that contain asbestos. “If we had a larger BOMAG mill, we would definitely be using it on those jobs.”

How to Mill With Less Dust

Canadian companies turn to ion technology to combine fine dust, clear air for milling crews.

Denis Lussier remembers how dusty the work could be when he started as a milling machine operator at ACI, Joliette, Quebec, in 2007. “Sometimes, there would be so much dust it looked as though a cloud of dust was moving forward down the highway,” Lussier said.

Throughout the past two decades, original equipment manufacturers (OEMs) have worked hard to reduce the amount of dust around their milling machines—to much success. “All of the companies that make these machines have innovated to reduce the amount of dust the operators experience when using these machines,” Lussier said, from water systems that suppress the dust to vacuum systems that collect the dust.

Although this has had profound impacts on the amount of visible dust, these innovations have also reduced the amount of fine dust surrounding the milling machine. Fine dust, while invisible to the naked eye, is actually more hazardous to workers’ health than visible dust, according to the Occupational Safety and Health Administration (OSHA).

While larger dust particles often fall to the ground quickly, fine dust particles can remain aloft much longer. Furthermore, our bodies are better-equipped to handle larger dust particles, which are often captured by our nose hairs, for example, whereas our bodies lack defenses against fine particles that can make their way into the lungs and cause health issues.

Bomag’s ION Dust Shield

In an effort to take silica dust suppression to the next level, ACI invested in a BOMAG BM 2200/65 equipped with the company’s innovative ION DUST SHIELD technology in June 2023. “The system makes it so we have almost zero dust on our jobs,” Lussier said. Now, he’s a technical advisor and training manager at ACI, making decisions that impact the company’s current generation of equipment operators—like the company’s new BOMAG milling machine with ION DUST SHIELD.

“This is a hard job, but this innovation makes it a bit easier,” Lussier said. “The system is easy to use, easy to clean, and it’s a very good step for our industry to prevent employees from breathing in dangerous silica dust.”

Founded in 1998, ACI specializes in cold asphalt recycling and is the largest milling company in Quebec, operating throughout the entire province. Since ACI’s inception, the company has milled approximately 1.6 billion square feet (150 million square meters) of the Quebec road network.

How the ION DUST SHIELD Works

The ION DUST SHIELD is an addition to BOMAG’s standard dust extraction system. The system, which received the silver medal of the BAUMA Innovation award in 2019, reduces the amount of hazardous fine dust by 88%, according to the manufacturer.

The system works by applying an electrical charge as the fine dust passes through the ION DUST SHIELD. The positively charged fine dust becomes unstable and tries to stabilize by bonding with other fine dust particles. As more fine particles clump together, they form coarse dust that can then be ejected with the milled material via the conveyor belt.

The ION DUST SHIELD does not rely on filters, which reduces the need to clean, service and dispose of these filters as a hazardous material.

“As people have learned about the ION DUST SHIELD, interest in the system is growing,” said BOMAG Product Manager for Cold Milling Dennis Frenzius, adding that the greatest interest so far has been in Europe. “There’s a lot of focus on fine particles in Europe as a result of conversations about reducing fine dust from standard mechanical brakes on cars.”

How to Dispose of Silica Dust

Furthermore, BOMAG has performed tests on the ION DUST SHIELD with health institutes in both Germany and France that have illustrated the system’s capabilities to reduce fine dust by 88% or more. “Now, we’re working on having similar discussions and tests with organizations in North America,” Frenzius said.

Although the North American tests have yet to occur, interest in the ION DUST SHIELD has been growing in these markets, Frenzius said, adding that every BOMAG milling machine with a front loading conveyor sent to Canada this year has been equipped with the ION DUST SHIELD. “Having the ION DUST SHIELD in the market improves visibility for this technology,” he added. “Whenever people become aware that there are new technologies to manage fine dust particles, that drives the discussion forward.” For example, World of Asphalt 2024 in Nashville drove a lot of interest in the system in the U.S. market.

“Our customers are very interested in protecting their operators from silica dust,” Frenzius said, adding that it’s also a matter of employee attraction and retention. “Interest in running a piece of machinery like this will be impacted if the operator’s health is at risk. That makes the ION DUST SHIELD even more important, because it offers the operator the highest level of protection available.”

Prioritizing silica dust suppression is not only important for operator health, but the health of others in the project area, such as the sweeping, paving and road marking crews behind the milling machine and pedestrians.

Frenzius stresses the importance of positive protection from silica dust, such as the ION DUST SHIELD, which is a useful addition to the PPE. Frenzius also recommends not relying exclusively on water systems, as fine dust is often too small to bind with water due to the surface tension of the water droplets.

Frenzius stresses the difference between coarse dust, which is often visible to the human eye, and fine dust (the type of dust targeted by the ION DUST SHIELD). Fine dust, while invisible to the naked eye, is actually more hazardous to workers’ health than visible dust.

Stay Ahead of New Standards

Although masks currently aren’t required on most milling projects in Canada, companies are preparing for a day when the silica dust standards become more strict. “In Europe, there are inspectors who come out to test the dust around these machines,” Lussier said, “and that’s eventually how it will be in Canada.”

On the other side of the country, Command Equipment Ltd., Edmonton, is also getting ahead of anticipated changes. “We don’t have inspectors coming to our jobs or anything, but they are starting to get stricter up here in Canada,” said Doug Booth, superintendent of Command Equipment’s milling division. “We want all our employees to be safe and healthy, and it’s important for us to investigate solutions to the problems they face.”

Command Equipment began using the ION DUST SHIELD in summer 2023. The company already had one BOMAG BM 2200/65 and needed another for a mill-and-fill project on Queen Elizabeth II Highway from Lacombe to Red Deer (18.6 miles/30 kilometers) for the Alberta Ministry of Transportation. The second BOMAG was equipped with the ION DUST SHIELD, so Command Equipment decided to put the new technology to the test.

“That’s a heavy commuter route, because it’s the main highway from Edmonton to Calgary,” Booth said, adding that the road had experienced significant surface cracking as a result of age and heavy use. Command Equipment was hired to mill to a depth of 2.4 inches (60 millimeters) and repave overnight to reopen each section of fresh pavement by the following morning.

Broce Manufacturing Leads the Way in Silica Dust Control for Sweepers

They milled one lane (7.2 feet or 2.2 meters) with their BOMAG with ION DUST SHIELD and one lane with another milling machine. “It was really good to perform a side by side comparison,” Booth said. “The guy running the BOMAG said he wasn’t getting as much dust and stuff blowing back at him as on the other machines.”

Command Equipment’s milling division operates four milling machines and performs almost exclusively highway work throughout Alberta and into the Northwest Territories nearly up to Yukon.

Booth has worked at Command Equipment for 15 years and in the company’s milling division for seven before being promoted to superintendent last year. “Whenever a new machine comes in, I like to kick the operator off and try it out, like it’s a new toy,” he said. “I like that the ION DUST SHIELD is easy to use. You don’t have to do anything. It’s just there and it just works.”

“Although the ION DUST SHIELD doesn’t make us run better or faster, it does make the environment healthier for the operator and ground crew,” Booth said. “Our company is all about investing in the safety of its employees, so this was an investment they made to make our lives a little better.”

The ION DUST SHIELD is an addition to BOMAG’s standard dust extraction system. The system works by applying an electrical charge as the fine dust passes through the ION DUST SHIELD, seen here atop the conveyor.

Relationships & Results

ACI first rented the BOMAG BM 2200/75 in 2020. The company has long had a great relationship with SMS Equipment Inc., which became a BOMAG distributor in 2019. “We find we have better service from SMS than from other dealers,” Lussier said. “Milling machines are prone to breaking down given the job they do, so it is very important to have good service.”

After the company had used the machine for a while, BOMAG invited ACI employees to Charlotte to see the new BM 2200/65 model, to discuss their experience with the machine, and to brainstorm the features they’d like to see on the next generation of BOMAG mills. “We’ve learned that BOMAG is a company that really listens to their customers,” Lussier said.

For example, ACI found the earlier version of the BM 2200/75 they rented several years ago was a bit too noisy. On the BOMAG BM 2200/65 ACI purchased in 2023, BOMAG put the fan at a 45-degree angle at the back of the machine for a quieter work environment for the operator. The new machine also came with the ION DUST SHIELD included. “That wasn’t something we had to choose to add on or pay extra for,” Lussier said. “It is a useful feature that comes standard in Canada.”

According to Lussier, the company considers the amount of dust they anticipate on a project when deciding which jobs to send its BOMAG mill out on. For example, if the company is planing concrete or milling in confined areas such as tunnels and under bridges. It’s also great when milling into the wind. “The water and VCS systems work well to suppress dust in most situations, but it’s been great to have the ION DUST SHIELD, too, when we have to mill into the wind,” Lussier said.

Where the BOMAG BM 2200/65 has most excelled for ACI is on projects where the crew must immediately pave after milling—for example, when the company recently milled and repaved highways 40, 35 and 10 overnight and had to reopen them by 5 a.m.

“On these types of jobs, we have to put down less water so the surface is ready for paving shortly behind the milling machine,” Lussier said, estimating that they run the water systems at 20% on these jobs compared to 100% on jobs without this time constraint. “When we must use less water, the ION DUST SHIELD is perfect because it can help capture that extra dust.”

According to Lussier, ACI has 14 employees trained to use the BOMAG mill. “They all like the ION DUST SHIELD very much,” Lussier said. “They say that when they run this machine, they experience no issues with dust.”