July 2003
Taming the Haul Road Dust Demon
Sister company provides Martin Marietta’s Chico Quarry with an innovative dust control solution.
One truck (left) generates enough dust to hide it from view on a dirt road without dust control.
Nothing in Texas is ever done pint-sized. So when Martin Marietta Materials’ Chico Quarry wanted to grow operations and expand services for its customers, it needed to build a Texas-sized road to accommodate them.
Issues regarding dust abatement and the proposed new 1.5-mile road loomed large, and quarry management had to consider all their options and think seriously about the costs to meet environmental standards.
However, customer service and community relations were also powerful motivators driving the Martin Marietta team, so they put together a program that not only had their customers very pleased, but the local townspeople of Chico as well.
Rich limestone deposit generates volumes
Martin Marietta Materials’ Chico Quarry, located outside Chico, Texas, 60 miles northwest of Dallas-Fort Worth, sits on one of the richest limestone deposits in North America known as the Bridgeport Quarries Area. The Bridgeport area ships 67 percent of its annual 28 million tons of limestone into the Dallas-Fort Worth Metroplex for construction and building projects and consumption by local residents. Developed in the early 1980’s, Chico Quarry produces enough material annually to build the equivalent of more than nine Empire State Buildings.
Its primary crushing operation includes a Nordberg C160 jaw crusher and a 7-ft. standard Symons cone crusher that produces 6-in. rock. The secondary crushing operation has one 4-ft. standard and one 4-ft. shorthead Symons cone crusher with two 8- x 20-ft. Deister and Hewitt-Robins screens that produce 1-1/2-in. rock and manufactured sand products. Add to this the Terex and Caterpillar fleet of 13 trucks ranging from Model 980’s to Model 990’s, the on-site asphalt plant and ready-mix operations that are contracted out, and you have a Texas-size operation. Recent expansions — including a new load-out house, maintenance shop, office building and quality control lab for product specification and quality review — have also added to the scale of operations.
Chico Quarry customers’ large trucks travel through the town of Chico, traversing turns, stoplights, and pedestrian traffic. Since Chico Quarry is the only quarry in the area with a 24/7 shipping operation, the traffic was a constant beehive of activity. Chico Quarry Plant Manager Richard Perkins knew there had to be a better way to move his customers in and out of the quarry while easing congestion, frustration, and travel distance for them. At the same time, he also wanted to appease the Chico community, so Perkins and his management team set about reviewing their options and discovered they could re-route the customers through the back door of their quarry by constructing a 40-ft. wide, 1.5-mile long road right on the existing property. It seemed an easy enough solution with no permit restrictions or property right-of-ways to worry about. However, it was the cost of a successful haul road dust control program that ended up being the real demon they had to conquer.
Not all dust control methods are equal
After discussions with Martin Marietta’s Area Production Manager Ron Douglas, Perkins formed a core team of internal personnel to review and analyze all their options. That team included Supervisors Ed Lawrence and Marty Casillas as well as Robert Taeger, who is in charge of environmental issues for Martin Marietta. Taeger has a very good relationship with the Texas Natural Resources & Conservationist Department and is very familiar with the guidelines and restrictions established for controlling dust emissions, especially the EPA’s PM10 standards regarding fugitive dust.
Martin Marietta has always been a strong advocate of dust control, and it wanted to maintain its environmental record when building the new road. Knowing that it wanted a long-term fix to the problem rather than a quick solution, the management team took an extensive look at the issue of dust control versus dust prevention. Its review included an analysis of initial costs, application requirements, product effectiveness and durability, maintenance factors, and long-term costs.
Traditional haul road dust control methods center on the application of water, more water and then again, more water. Some other products typically used include salt, calcium chloride, magnesium chloride, petroleum products and even soybean oil, but the team felt that each of these options had limitations and problems with absorption, evaporation, and run-off.
Chico Quarry owns a water truck and has practiced the water method of dust control on its existing quarry roads. However, water in the Metroplex area is quickly becoming a highly valued commodity and is being designated for the more primary purpose of supporting a growing population, so spraying water on roads is less attractive to many of the local quarry operations. In addition, if Chico Quarry was going to be able to effectively control the fugitive dust on the new road, then it would have to purchase or lease another larger water truck for the job. This was not an expense the team wanted to incur, but important to factor in, unless it could discover a more cost-effective option to control the dust.
Deciding that the quarry needed new and innovative ways to suppress dust, Perkins and his team entertained several manufacturers’ and vendors’ suggestions and alternative products. However, it was sister division Martin Marietta Magnesia Specialties that actually had the answer they were looking for in its HR-51 product, an acrylic co-polymer that is specifically formulated to act as a sealant and suppress dust on haul roads and is environmentally safe and requires no hazardous warning labels.
It wasn’t a cakewalk for David VanOverschelde, regional sales manager for Martin Marietta Magnesia Specialties, to convince the Chico Quarry team that it needed to purchase HR-51. VanOverschelde says, “Even though we belong to the same corporate organization, Martin Marietta Materials, each group is a separate unit responsible for its individual businesses, and neither of us are required to buy from the other division.” VanOverschelde had to work hard to sell the benefits of HR-51 against lower-priced alternatives such as calcium chloride. VanOverschelde had to show that HR-51 would provide the long-term, cost–effective solution Perkins was demanding.
Savings comparison
A typical quarry or haul road operation consists of approximately one mile of 30-ft. wide roadways with several additional acres of areas requiring dust control. The total area of coverage of this size is approximately 32,000 sq. yds. To effectively control dust for 32,000 sq. yds. in a single day would require at least two or more passes per square yard by a water truck. Two water trucks in continuous operation can cover the entire 32,000 sq. yds. with a single pass in an eight-hour day. Martin Marietta Magnesia Specialties’ experience with many operations and quarries shows that the average daily cost to control dust from haul roads with water is estimated at $400.
HR-51 is typically diluted at a ratio of 10:1 with water, and during the initial application a primer application is followed by another layer that functions as a sealant. Maintenance and re-application requirements are determined by the volume and frequency of road use. However, the wearing factor for HR-51 is very gradual and re-applications actually bond with previous ones, thereby dramatically reducing the frequency of future treatments. Maintenance applications will continue throughout the second and subsequent years on a less frequent basis and there will be a continuing buildup of HR-51 in the soil as the dust becomes heavier and much less likely to become airborne. While accumulated traditional water application costs increase over time, HR-51 costs decrease over the same time period. Even in the first year, HR-51 will not exceed the estimated cost for water truck operations regardless of the amount of product that might be required to complete the task, according to the manufacturer. It is conservatively estimated that the HR-51 dust control program will save at least 50 percent over a five-year period over traditional water control methods.
Plant Manager Perkins is very satisfied with the team’s decision to go with the HR-51 product. “HR-51 is not a patch. It’s a fix for the longer term.” He adds, “HR-51 has substantially reduced my costs, and I am definitely considering it for other areas of the quarry.”
Simple, fast application and maintenance
The new, 40-ft. wide, 1-1/2-mile long Chico Quarry road was the largest application VanOverschelde and Martin Marietta Specialties had yet faced. The required tools for application of HR-51 consist of a motor grader, pneumatic compactor, and water truck. Scarifying the road surface to a 3-in. depth is highly recommended as it helps the product sink into the ground and creates layers that seal better.
The product is best applied in temperatures above freezing since frost can inhibit the drying process by preventing the evaporation of the water. The first time HR-51 is applied, the product is mixed with water at a ratio of 10:1 per square yard. The lay down procedure starts with applying one-third of the total mix and then compacting the soil. Apply another one-third and compact the soil again. Apply the final one-third of the total mix and compact the road surface using a drum roller. It sounds like a time-consuming process, but the Chico Quarry team completed the process in just 16 hours on the 1.5-mile long road.
HR-51 bonds with the aggregates in the soil and forms a hard, sealed surface with no residue and dramatically increases soil strength and resistance to moisture. The level of activity on a road determines the frequency of maintenance coats. With build-up of the product after each application, subsequent maintenance applications can be mixed at a ratio as high as 15:1. Chico Quarry averages 30 to 45 days between maintenance coatings, taking the crew less than 20 minutes to lay it down on the 1.5-mile road.
All roads will experience wear-and-tear from the abuse of thousands of trucks traveling it. However, the surface of a road treated with HR-51 is actually malleable. To compensate for normal wear-and-tear you can spread a layer of pea gravel on the road, allow the weight of the trucks to compact the gravel into the existing road surface, and then apply a maintenance coat of HR-51 that will bond with the aggregates and seal the road. Chico Quarry’s Supervisor Ed Lawrence has also found other unique applications for HR-51. He and his crew will take loose rock from the shoulders of the road, put it in potholes around the quarry site, add some HR-51 and compact it as a quick and effective repair method. HR-51 also provides an alternative to asphalt emulsion for cold-in-place recycling of old asphalt roads.
Listen to the silence
Probably one of the most satisfying benefits of Martin Marietta Chico Quarry management’s decision to build a road on the quarry site has been the resounding appreciation from the local community residents. While Martin Marietta prides itself on customer satisfaction and community relations, it wasn’t prepared for the positive reaction of the local community. The local newspaper received many unsolicited “Letters To The Editor” stating appreciation and gratitude to Chico Quarry for re-routing the truck traffic away from the center of town and contributing to the peace and safety of the community at large. The town was not used to the sudden silence and actually had to adjust to the reduction in noise levels and constant truck traffic. Perkins credits his team of employees for the success of the quarry operation and the relations they have with their neighbors. “The Martin Marietta operation is a success due to great teamwork. There is no ‘I’ in teamwork,” Perkins proudly states referring to the actions of his employees.
It is this focus on service to its customers and community, strategic planning for the long-term, and the focus on containing costs that makes the Martin Marietta Materials’ Chico Quarry a successful operation in today’s competitive environment. With additional growth plans in mind, Perkins and his group will be approaching other issues associated with expansion with the same care and attention to detail that they have shown in cost-effectively resolving this haul road dust control demon.
Martin Marietta Materials’ Chico Quarry Supervisor Marty Casillas, Plant Manager Richard Perkins, and Supervisor Ed Lawrence (left to right) were part of the team that selected and implemented the operation’s dust control measures.
Plant Manager Richard Perkins has been in the business for over 30 years and came from a major competitor two years ago to join the Martin Marietta Materials’ Chico Quarry organization. Perkins’ team leadership abilities earned him the Martin Marietta Leadership Award his first year with the organization.
Chico Quarry Sets High Safety Standards
He respects his employees, involves them in the decision-making process, and modestly refuses to take all the credit for the success of the quarry. He gives credit where credit is due and knows it is the employees that make things work.
The employees also have a strong sense of safety and were instrumental in establishing the “Guardian Angel Creed.” This is an employee-based safety program that all 60 employees participate in through bi-weekly safety meetings, weekly tailgate meetings, and an annual refresher program.
Also, posted at the entrance to the quarry site are the safety rules and guidelines all visitors, vendors, and customers must observe when conducting business on the Chico Quarry site. Everyone has high regard for Perkins and his team and respect the focus on safety.
Information provided by Martin Marietta Magnesia Specialties.