Southwestern Energy is involved with natural gas drilling throughout the country, including a substantial portion of the state of Arkansas, within the Fayetteville Shale.

“We cover well over a million acres here,” says Kevin Cotton, structural superintendent for Southwestern Energy. That also involves a great many roads leading to and from the drilling sites, many of which require dust suppression from the effects of heavy drilling equipment moving along these roads. Not surprisingly, few of the involved roads, covering nearly a quarter of the state, are paved.

“Up here in rural Arkansas, 98% of the county roads are gravel,” he says.

Although he applies dust control perhaps two or three times a week near the various drilling sites, Cotton singles out one recently treated stretch of road just north of Cleveland, AR, in the central part of the state.

“We had an extremely steep hill, with a large amount of traffic that we run up and down. We were able to utilize the PennzSuppress product with the right amount of SB2 rocks and fines, and blend everything together in layers and nearly pack it down as asphalt, as opposed to asphalt proper. We saved probably 80% doing it this way, rather than laying asphalt.

“We would put SB2 down, blade it and roll it back, apply a layer of PennzSuppress, than blade it and roll it back again, going back and forth with it. Basically, we’re working it into all the rock, and rolling it in between passes, for a smooth finish.”

Ramco Environmental is the local distributor and applicator of PennzSuppress in the region, and company vice president Jason Ramsey explains that the application for this particular road near the town of Cleveland stretched for about 2,000 feet.

“We do a lot of the private lease roads in the area,” he says, “in addition to coordinating a lot of dust control with county roads. Southwestern oversees a lot of the maintenance of the county roads going to and from these drilling sites.”

Not all of the roads being treated are county roads. As Ramsey notes, there are also private lease roads that are used for the drilling sites. Some roads are in use only for the life of the well, and this can vary greatly from site to site.

“Sometimes a job has phases,” Ramsey adds. “There’s the construction of the pad, then it goes into the drilling phase, maybe with two different sets of rigs. Then it goes into the completion phase, when they’re fracking. So the life of the well comes in different phases. The time periods can vary. Then it goes into the production phase.”

All these phases may require dust control, depending on conditions.

“Typically, when we have activity in a specific area, we will go in and apply the dust control to a county road, to help keep the community happy,” Cotton says. “Just being a good neighbor.”

Southwestern Energy has relied on PennzSuppress for several years for reliable dust control. Cotton appreciates the speed of application. “We can do a good stretch of road in a day’s time,” he says. “These applications will typically last us a month or better, and that will usually get us through a drilling cycle or a completion cycle. It may need to be touched up after heavy traffic has been on it for a month.”

Ramsey adds, “Depending on the specific application, sometimes it can last for months, with some touch-up maintenance to take care of some fugitive dust that may have been tracked on to the actual surface itself.”

Dust control is very weather dependent, according to Cotton. “We’ve got a lot of inspectors in the fields. On county roads, we’ll get phone calls from landowners letting us know that the dust control has worn out. We can then go back and put in another application or whatever we need to do. But we will not apply 24 hours prior to a forecasted rain event.”

Application following a rain, however, is no problem. “A little bit of moisture on the road actually helps it,” says Cotton.

PennzSuppress is applied using vacuum trucks with pressurized spray application equipment.

“We try to get the most consistent, even application that we can,” Ramsey explains. “We want to get the most material on the surface that we are treating. We can raise or lower our bars up to 18 feet wide, and go all the way down to 4-foot narrow stretches if we have to. So we can customize our spray patterns based on the road configuration.

“PennzSuppress is a paraffin resin-based material that we blend with water. This allows us to custom blend application rates based on the purpose. It’s easily handled; it doesn’t have to be heated at all.

“We usually use a 4:1 application rate, 4 gallons of water to every gallon of PennzSuppress. This is a pretty good standard that we’ve had a lot of success with in the field.”

He notes, however, that in arid environments, this application ratio may need to be altered. A greater proportion of water may be necessary to lower the viscosity of the product and improve penetration into the road surface.

Regardless of the dilution proportion, as the product penetrates the ground, the water evaporates, allowing the active ingredients in PennzSuppress

to bind the dust-producing aggregate, building a cohesive surface. A non-water-soluble petroleum resin is the active ingredient in the product, and this remains in the road surface, continuing to provide dust control through both dry and wet conditions, and minimizing the ill effects of freeze/thaw cycles.

“A good thing about it is that it is water resistant,” says Ramsey. “It doesn’t migrate off with a rain event, like a lot of other materials do. Also, it doesn’t break or crumble under heavy stress or shearing, such as the heavy equipment that runs the roads. Those 80,000 to 90,000 pound loads coming in with drilling equipment don’t compromise the integrity of the PennzSuppress application.”

While there is no revegetation work on the Cleveland road, Ramsey notes that PennzSuppress can also be used as a seed tackifier.

Cotton says that he has received little feedback concerning his dust control work, but for that, he’s happy. “Our best feedback comes from not having a complaint call,” he says.

Ramsey says that at times, though, the neighbors can be quite enthusiastic. “Some of our operators get stopped on the roadside by some of the residents thanking them for the service. They tell the operators that they appreciate us and Southwestern Energy for doing what they’re doing. Sometimes in the summer they’ll have a barbeque on their deck. We’ll go by and they’ll clap their hands, or give us a thumbs up. We get that a lot. It’s a win-win for everybody. It’s about relationships and operating well within the communities in which we work.

“This work is a great public relations tool, and it helps the counties out. It helps everyone, keeping the dust down.”

Dealing with Desert Dust Storms
The Antelope Valley Solar Ranch (AVSR) is located approximately 80 miles north of Los Angeles. When fully operational, it is expected to generate 230 MW of electricity, enough to power 75,000 homes in northern and central California.

The region is home to a number of solar arrays, and the town of Lancaster, in the vicinity of the AVSR, requires solar power for all new homes within its borders. Located in the desert and not far from existing transmission lines, Antelope Valley seems well suited for collection of solar power.

But it is also an area with frequent high winds. Coupled with construction activities for the solar arrays, a great deal of dust can get moving through the area quickly, putting residents at risk of contracting valley fever, which can occur when fungal spores in the ground become airborne and are breathed in.

In April 2013, a powerful dust storm roared through the area, causing a 20-car pileup on State Route 14. The California Highway Patrol reported a total of 18 dust-related accidents at the time.

Not surprisingly, dust is a prime concern in the region. In fact, construction was temporarily suspended on the AVSR project following the epic April dust storm until improvements in dust control could be implemented.

“There was one major, major issue out there that everyone was concerned with,” says Tyler Palmer of TerraNovo, manufacturer of EarthGuard Fiber Matrix. “There are lots of neighbors surrounding these areas that complained a lot. So dust control was a high priority for this job, from the beginning to the end.”

The portion of the project that Palmer was involved with covered about 1,600 acres. “We treated underneath the arrays and in large graded blocks of land. Each block was 160 acres. They mass-grade those, then they come in and pound their posts and put up the arrays. After they grade, they need dust suppression, so they decided to use EarthGuard Fiber Matrix and were spraying that underneath the arrays. This helped control the dust associated with those areas.”

The product is applied with a hydroseeding machine. The intent is that a single application will provide a year’s worth of dust suppression. “It holds everything down, until you get the seeds to grow through,” Palmer says. “But they haven’t done the seeding part of it yet. Right now we’re just doing it for dust control.

“They’re still waiting to see what the plan is to reseed the area. They are collecting native seeds within a certain radius of the property. That has slowed things down, because of the cost of various aspects of the project. We’re not sure exactly how they want to go about reseeding. They just don’t want to break the bank doing it.”

He notes some of the challenging aspects of the project. “It’s a high-wind area, this Lancaster-Mojave Desert area. There are very high winds, but they also needed something that was going to be able to take some foot traffic as well as deal with the 50 mile-per-hour winds that they receive out there. This also helps from a stormwater perspective. It helps keep the stormwater clean as it leaves the site, as a secondary benefit to doing the dust control.

“I think the most challenging part was the amount of work the applicators had to do to get the product down in between the arrays that were already up. Then they also had to deal with the high winds out there. Spraying these projects with such high winds makes it a real challenge for the applicators, but they did a fantastic job with all they had to deal with.”

Dust suppression under the solar arrays was achieved with TerraNovo’s EarthGuard Fiber Matrix, which is composed of EarthGuard combined with wood mulch. But Palmer adds that there are also haul roads onsite that allow workers to drive around, inspect the work, and do maintenance operations. Around those haul roads, a different product, DustGuard, was used.

“These were highly traveled roads, for the maintenance crews and others,” says Palmer. “So a lot of people used these roads, which are just dirt. With a project this size, having that many cars going over the roads, together with the shortage of water that they have out there-they were looking for a product they could put down. This allowed them to get four months of dust protection on the road without having to water it every single day, all day long.”

He explains that once DustGuard dries, it cures and doesn’t re-emulsify. He says DustGuard was the better choice for heavy traffic flow, while the EarthGuard Fiber Matrix was more suitable for the non-traffic areas around the arrays themselves.

The haul roads helped ease any access problems that might otherwise have occurred. In some instances, crews had to work around solar arrays that had already been connected, spraying underneath them. In other spots on the site, a large area would be graded, followed by the EarthGuard Fiber Matrix application, and afterward the arrays would be set up.

While there is not a great deal of foot and vehicular traffic traveling over the EarthGuard applications, Palmer notes that it has held up well to the post-pounders and light traffic moving over the material. “It doesn’t form a real hard crust when it dries,” he says.

Grounding Airport Dust
“Blowing dust had been a growing problem at the airport in Lima, Peru, and nothing had been done for years,” says Andy Stevens of Enviroseal, based in Florida.

“LAN Airlines, the main airline of South America, had issues with the airborne dust. They had told the airport that they were going to pull out, and they are the largest airline operating at the airport. They were going to pull out and just not fly in and out of there again. And Lima’s is one of the largest, busiest airports in Latin America.

“The airport, of course, didn’t want to lose its biggest airline. It would be like Delta telling Atlanta Hartsfield that they were going to pull out. So the airport decided they needed to do something about the dust. It’s a major safety issue. The planes couldn’t see the tower, and the tower couldn’t see the planes at times. The problem wasn’t only from windblown dust, it was also from the jet blasts from the shoulders of the runway.

“In 2008, Lima Airport Partners, which is the consortium that operates the airport, had investigated about 20 different products from around the world. After evaluating all these products, they selected our M10 product, based on how well it came through the tests, providing a good covering,” says Stevens.

Enviroseal provided a topical application that was applied at 500 milliliters per square meter. “I had pigmented the product green, so it would look like grass, and also to reduce the ultraviolet degradation of the material. All polymers will degrade in ultraviolet light,” he notes.

“It had about a four-and-a-half to five-year life span. Then in 2012, they requested another application. But they hired a contractor from Spain who shopped around for the cheapest product he could find. They went around us and bought a much cheaper product. They did their stabilization, with full-depth stabilization at 15 centimeters, and then they did a topical application. That application only lasted four weeks. It just dissipated. It was basically colored water. They shipped a very low-quality product. It was a vinyl acetate, and the vinyl just couldn’t stand the UV, and it degraded rather quickly.

“So at that point, there was no dust control. Absolutely none. They were out of the budget, and I believe the contractor got in a lot of trouble for not doing due diligence.

“They needed an emergency application, and bought a few containers of my product for the emergency application in 2012. In 2013, they moved forward with a much larger order, and that was the last application we’ve done there, in May 2013,” he says. “The last time I was down there, the director of maintenance for the airport told me that they will never make that mistake again.”

For dust suppression, the Enviroseal team initially stabilized the shoulders, 30 meters on each side of the 3-kilometer-long runway. Stevens notes that this application had a dual purpose. The first is dust suppression. The runway was built about 20 years ago, when planes were smaller. As airplanes get bigger, their wingspans grow larger. The result is that the jet blast encompasses a wider area than the runway was originally designed for, so the runway shoulders needed a wide area of dust suppression.

The second purpose is safety. When a plane goes off the runway, the wheels won’t sink in if the ground is properly stabilized. Oddly enough, this appears to be a common enough problem to warrant treatment.

The Enviroseal M10 product used is a blended liquid acrylic copolymer suspended in water by surfactants. On the job site, water is added to the mixture. As the water evaporates, the polymer particles begin to coalesce, forming a durable type of plastic.

For dust control, the mixture is topically applied, either from a hydroseeding machine or from another type of spray apparatus.

“The curing period depends on ambient conditions,” Stevens says. “Because it is water based, we rely on the water to evaporate, which leaves a polymer behind. So the lower the humidity and the higher the temperatures, the faster the curing.

“The application rate really depends on the soil type itself. If you have, for instance, a sandy soil, when you spray a liquid on it, it will permeate in through the soil, like water going through a coffee filter. On the other hand, if you have more of a clay soil that does not allow the liquid to permeate, it will pretty much just sit on top.

“We have the ability to custom formulate, depending on the soil conditions. If we know we’re dealing with a heavy clay soil, we’ll add surfactants or wetting agents into the material, which helps to get absorbed much faster, and with a deeper penetration.

“We always recommend soil testing. If my product is not right for the application, I do not want the customer to buy it. Let’s face it, a lot of people in this dust control industry have given it a bad name over the years. That contractor from Spain is a typical example. Even here in the US, there are a lot of companies that enter the market and then they try to sell a cheap, inferior product. They tout it as being the best thing since sliced bread, and it doesn’t perform. A lot of people then get jaded over it, and understandably so. If you’re going to spend quite a bit of money, you expect performance.

“That’s why I always insist that our customers do their testing. I encourage them to evaluate our product against the competition, because they may find that another product may work better for their application. If there is something out there that is going to work better, I suggest they use it.

“Ideal conditions generally are in warmer, arid climates, historically, for polymer-based products. Of course, being water-based, you want it to cure faster. If it’s raining, it’s hard to apply water-based product and have it cure-the same if it’s very cloudy or overcast.”

Nevertheless, Stevens adds that he does not do a great deal of work in the arid American Southwest.

“The reason is transportation costs,” he says. “I’m here in Florida, and for me to transport a full load of materials to California or Arizona would cost me more than it would to send it to just about any port in the world out of Miami. I can ship a 20-foot container to China for under $1,000, whereas the same amount of material would cost me $5,000 to $6,000 to truck it to California.

“In fact, most of our business is international,” he says. “With our office being located in south Florida, we’re the gateway for South America. A lot of our business goes down south. We’ve been doing projects in just about every Latin American country. We’re looking at projects now in Ecuador, Colombia, Venezuela, and Chile.

About the Author

Steve Goldberg

Steve Goldberg writes on issues related to erosion control and the environment.