In 2024, new dust control regulations for the mining industry went into effect. These rules aim to provide a safer working environment, protect nearby communities from fugitive dust, and save lives by lowering the risk of respiratory illnesses.
Now, mine operators face a daunting task: reducing fugitive dust levels by more than half. And if dust levels are too high, you could find yourself staring down the barrel of MSHA fines, production shutdowns, and—most importantly—health risks to your employees.
To help you avoid these pitfalls and protect your team, we’re answering common questions about fugitive dust and the new MSHA regulations. Then, we’ll compare four dust suppressants that you can use to treat one of the worst culprits of mining dust: site roads.
Fugitive dust is small, airborne particulate matter. Mining dust control regulations focus on a specific type of dust called respirable crystalline silica—or silica dust for short.
Crystalline silica is a common mineral in rocks, sand, and soil. During normal mining operations, it becomes airborne. Miners then inhale these microscopic particles—hence why we call them respirable. This dust also blows into nearby communities and waterways.
Everyone in the mining industry knows silica dust is dangerous, causing respiratory diseases, cancer, and death. The Mining Safety & Health Administration (MSHA) regulates permissible levels of respirable crystalline silica on mine sites. Like most mine operators, you’ve spent decades following these guidelines to protect your employees.
However, MSHA’s previous standards for mining dust control were based on limits that the American Conference of Governmental Industrial Hygienists (ACGIH) adopted in 1973.1 We've learned a lot about silica dust and its health impacts since then, and that knowledge led MSHA to implement the new, more stringent guidelines.
One of the biggest changes in MSHA’s new regulations is that they create uniformity. All mines now have uniform permissible exposure levels (PEL) and action levels (AL) for all types of crystalline silica dust—quartz, cristobalite, or tridymite varieties.
The new PEL is 50 μg/m3. Let’s explore what that means and how it compares to the old regulations.
The permissible exposure level is the amount of airborne silica dust that experts believe miners can inhale without serious, harmful effects. Sampling devices measure how much dust is in the air using the ratio of micrograms (μg) per cubic meter (m3), or μg/m3.
In the past, metal/nonmetal (MNM) mines had different standards for different types of silica dust—ranging from less than 100 μg/m3 for quartz dust to less than 50 μg/m3 for cristobalite and tridymite dust. For coal mines, the standard was 100 μg/m3 for dust. And in both cases, mine operators had to measure dust levels during a full shift.2
Under MSHA’s new regulation (30 CFR PART 60), the PEL for MNM mines’ quartz dust and coal mines is cut in half. To determine if they meet the new requirements, mine operators must take air-quality samples:
The action level of crystalline silica dust is 25 μg/m3. Once this amount of silica dust is in the air, MSHA requires a mine to reduce it. It’s all in the name: when your dust samples hit the action level, you have to take action to fix them.
Like the new PEL, the new AL is uniform for all mines and types of dust. But, why is the AL set at half the PEL?
The new dust control regulations require mines to take initial samples at least seven days and no more than three months apart. After achieving compliance, they’ll undergo evaluations every six months. These samples and evaluations may get scheduled on a “low-dust” day, when mining operations produce less fugitive dust than usual. So, if the dust measures between 25-50 μg/m3, there’s no guarantee that dust levels stay under the PEL every day.
Thus, MSHA set the AL at 25 μg/m3 because, if the dust measures less than half of the PEL on multiple, random days, then it’s likely the mine is compliant with the regulations most (or all) of the time.
We’ve covered the basic definitions of fugitive dust and respirable crystalline silica, as well as MSHA’s new PEL and AL. For more information—such as how to perform sampling and what to do if your samples exceed the AL—visit MSHA's 30 CFR Part 60 Frequently Asked Questions page.
Every part of a mine where equipment moves produces dust—the mining machine, crusher, conveyor belts, drilling and blasting, roof bolting, tunneling, and so forth. You’ve probably already stepped up your dust control efforts in these areas, with MSHA’s new regulations in mind. That’s great!
Next, it’s time to include site roads in your plans.
While mining roads don’t produce the most dust, they are some of the worst culprits for spreading it. Moving traffic creates airflow that keeps crystalline silica particles aloft, blowing them across the mine site and into the community. Traffic also crushes soil particles on unpaved roads, creating additional dust that hinders your goals of 30 CFR Part 60 compliance.
Fugitive dust from dirt roads also decreases visibility, creating serious safety issues for surface mobile equipment. Visibility is already precarious when massive machinery and ordinary pickup trucks travel the same jobsite. In 2024 alone, nearly 40% of MNM mine fatalities and 50% of coal mine fatalities were due to powered haulage, and many of those involved surface mobile equipment.4
MSHA implemented the Safety Program for Surface Mobile Equipment in 2024 to try to reduce these fatalities. In addition to operator and miner training, it requires mines to:
Fugitive dust from site roads is a significant hazard that increases the odds of fatal collisions. So, by treating your site roads to suppress dust, you create a healthier working environment for your employees and get closer to complying with MSHA’s Safety Program for Surface Mobile Equipment and 30 CFR Part 60 regulations. That’s a win-win-win!
Mines rely on several common dust suppressants. The question is, how will those products hold up under the new regulations? We’ll compare four dust suppressants—water, mag chloride, lignosulfonates, and Perma-Zyme—and rank them on a five-star scale in terms of:
Lifespan: ⭐
Cost-effectiveness: ⭐
Eco-friendliness: ⭐⭐⭐
Water may last one or two days under the right conditions. But in arid regions under heavy traffic, it may only last a few hours. Some mines constantly run more than a dozen water trucks towing pup trailers to deliver extra water, and the roads are still dusty.
Water itself can be fairly cheap, but operating the trucks is costly. (If your mine has a water shortage, then you’re looking at the added expense of importing water.) As the new PEL takes effect, mines will see their water costs spike. And while water is eco-friendly, the trucks’ CO2 emissions aren’t. The sheer volume of water mines will need could also become unsustainable in areas with a limited supply.
Lifespan: ⭐⭐
Cost-effectiveness: ⭐⭐⭐
Eco-friendliness: ⭐
Magnesium chloride reduces dust and encrusts soil’s surface for stability. It works best in humid environments because it pulls moisture from the air around it to weigh soil down, preventing dust. However, it wears off with rain and traffic, lasting as little as three months. That’s a longer lifespan than water, so it is more cost-effective than running an army of water trucks. That said, the long-term costs of repeat reapplications add up.
Finally, mag chloride is falling out of favor with the public and mines alike for its harmful environmental effects. It contaminates water and soil, making revegetation difficult or impossible.
Lifespan: ⭐⭐
Cost-effectiveness: ⭐
Eco-friendliness: ⭐⭐⭐⭐
Lignosulfonates, also called lignin sulfonates, are an eco-friendly, plant-based dust suppressant. Lignin is a brown, cementitious substance that fills gaps between plants’ cell walls. This polymeric tissue provides structure to help plants grow tall despite weather and other stressors; it’s similar to the polyester resin that holds fiberglass car bodies together.6
Lignosulfonates can last longer than mag chloride—around three to six months in dry regions. Although they have water-repellant properties within plants, rain can quickly wash them off road surfaces. That's a big problem since one application can cost over $100,000 per mile, an astounding sum for a product that won’t survive the season. Lignosulfonates can also rack up equipment and labor costs. They’re made of tree sap, so you’re basically pouring molasses into your water trucks. That will take serious elbow grease to clean, and your crews could better spend that time on other projects.
Lignosulfonates’ best feature is that they’re non-toxic and eco-friendly. They come from a renewable resource, and they’re safe for the environment around your mine.
Fun fact: Although lignin consists mostly of sugar, livestock can’t digest it because of how its molecules bond together.7
Lifespan: ⭐⭐⭐⭐
Cost-effectiveness: ⭐⭐⭐⭐⭐
Eco-friendliness: ⭐⭐⭐⭐⭐
Perma-Zyme is a powerful, enzyme solution that works as both a soil stabilizer and a dust suppressant. It has more than 50 years on the market and satisfied users in over 25 countries.
Since its main purpose is to harden soil, Perma-Zyme’s soil stabilization lasts longer than its dust suppression. The good news is that both capabilities last longer than any other dust suppressants we’ve evaluated. The table below shows how long one application of Perma-Zyme lasts in different environments on the mine site:
Treating one mile of road with Perma-Zyme costs less than 10% of a lignosulfonate application. And while it costs more upfront than mag chloride, you’ll save on maintenance because you won’t have to reapply it multiple times per year. Long-term, mines can save tens of thousands of dollars with Perma-Zyme.
Finally, Perma-Zyme is sustainable. Its active ingredients are enzymes—natural proteins that living organisms like yeast and bacteria produce. Perma-Zyme is 100% natural, eco-friendly, and organic; in fact, 70% of ingredients are food-grade materials. It’s also non-toxic, non-hazardous, and non-corrosive. To reclaim treated soil, simply rip it up and let the enzyme formula biodegrade.
When applying Perma-Zyme, we recommend mixing it into the soil to maximize both its dust suppression and soil stabilization capabilities. Here’s how this application works:
In mining, there’s no way around dust. You have to move soil and break up rock to do your job and provide the materials our society needs to thrive. But with MSHA cutting the PEL down to 50 μg/m3 and setting the AL at 25 μg/m3, just suppressing dust in the most obvious places isn’t enough. Your best strategy includes suppressing fugitive dust on your site roads, too.
When choosing a dust suppressant, traditional options often fall short. No amount of water trucks can keep up with the new dust control regulations, mag chloride is environmentally harmful, lignosulfonates are expensive, and none of them last more than a few months.
You need a product that’s long-lasting, cost-effective, and sustainable. That’s why we recommend Perma-Zyme, the all-natural enzyme soil stabilizer that lasts for years at a fraction of the cost.
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