The plant at John S. Lane & Son set up and operating.
There are mountains in John S. Lane & Son's Westfield, Mass., quarry. Mountains of waste, dust and sand that cannot be used and for which there is no local market.
Most of the rock in the Westfield quarry is trap rock, a very hard aggregate material that is being produced to supply aggregate for JSL Asphalt Inc., as well as Lane Construction, which also has a major asphalt plant on site.
The Westfield quarry has been active for a very long time and one of the major byproducts of producing 3/8-inch through 1/2-inch aggregate is the waste, dust and sand that are growing into virtual mountains, also known as legacy piles.
These massive piles just continue to grow and in a quarry with a limited footprint, this eventually becomes an issue. According to Plant Engineer Mark Pfaff, there could be up to 2 million tons of legacy material at the Westfield site.
There is a small amount of demand to use some of this fine material for bedding (a product used when paving bricks are being laid), but there is not enough of a call for this product to even put a dent in the legacy piles, according to the company.
When producing asphalt for highway usage, the spec for the aggregate size is very tight. The government requirements for smoothness get more stringent all of the time and the spec for the aggregate in asphalt is just as narrow. In past years, the materials in the legacy piles could be incorporated into the asphalt mix as undersized material to a limited extent. Today's spec allows for a 200 size material to make up 0 to 5 percent of the aggregate.
Within the legacy piles, approximately 14 percent of the content is referred to as moon dust, or product that is so tiny that it cannot be used in aggregate production at all. If that moon dust could be removed from the product in the legacy piles, what is left can be used on a limited basis in asphalt production.
The traditional approach to remove the usable product from the legacy pile would be the creation and installation of a wash plant. Wash plants, however, require the installation of pumps and ponds for the separating out of the fines and periodic cleaning of the ponds, as well as disposal of the dust residue that is separated out by them. John S. Lane & Son and Pfaff were looking for a better solution. They wanted to find a way to stop adding to their legacy piles and, if possible, start reducing the size of them.
Pfaff met with aggregate equipment experts and the solution turned out to be wind, coming in the form of an air separator, manufactured by North Dakota-based Fisher Industries.
The air separator effectively removes unwanted fines of 3/8-inch minus in size from abrasive and non-abrasive aggregate materials using a powerful turbine that allows air and gravity to sort materials by size. It eliminates the need for wash plants and has a proven record of being effective with granite, limestone, trap rock, sand and gravel applications.
The fans within the unit can be adjusted to create different types of separation or to make adjustments as needed, depending on the moisture content of the materials. Moisture content of the material being processed is critical. Wet mixed material cannot easily be separated using air, so in extremely wet conditions this process can have its challenges. The drier the material is, the more efficient the process is.
To assist in this, the conveyors feeding undersized material from Lane's crushers are designed in a way to help the materials dry before entering the separator. Thus far, the results of using the Fisher air separator at John S. Lane & Son have been impressive, according to John S. Lane & Son.
“Up until now, about 15 percent of the product coming out of our crushers was a mixed undersized material that we deemed unusable and it went to the legacy pile,” Pfaff said. “With the addition of the Fisher separator in our spread, 85 percent of that unusable material is now usable, which dramatically decreases what is going to our legacy piles.”
“An additional benefit is that when time, weather and manpower permits, we are able to go back to the older sections of our legacy piles and recover 80 to 85 percent of the product in it as a sellable aggregate for asphalt production,” he added. “2016 was a very dry year in Massachusetts and it was ideal conditions for the use of the Fisher separator. We were able to achieve production levels of up to 120 tons per hour.”
John S. Lane & Son has been renting the unit for the past two years and this year, it will be purchasing it. The return on investment has proven to be substantial and the air separator also has proven to be economical to run, according to the company.
These machines do require some maintenance, however, and from time to time, the fans need to be replaced, depending upon the abrasiveness of the sand that John S. Lane & Son is processing.
“They are very affordable machines to operate,” Pfaff said. “When we do receive heavy rains and wet weather, we simply shut down the processing of the undersized materials and stockpile until the weather clears. We have a very good relationship working with EESSCO on this project. They are good business partners. We had worked with Christopher Salafia and Dick Vining in the past and we came into this project knowing that their support would be reliable.”
Another benefit of the plant is its portability.
“We can easily transport this machine to our other facilities as needed,” Pfaff said. “It's as easy as leveling a piece of ground, blocking and leveling the separator, connecting the conveyors and electrical panel, and turn on the hydraulic system which lifts the separator into position.”
About John S. Lane & Son
John S. Lane & Son is one of the leading aggregate producers in New England and is headquartered in Westfield, Mass. It has five mining operations, including four quarries and one sand and gravel pit. These operations provide crushed stone, sand and gravel to major construction projects in western Connecticut and central and western Massachusetts. The company produces a wide variety of aggregate products, but its primary focus is aggregate for ready mix, concrete and asphalt production.
John S. Lane & Son, along with JSL Asphalt, a significant participant in the supply and installation of bituminous concrete for northern Connecticut who specializes in all aspects of asphalt placement, are both divisions of JSL Material.
JSL Materials Inc. has been in the construction materials industry since 1890. The company was founded through the pioneering efforts of John S. Lane, who was employed by the railway. Lane had the foresight to identify the need for aggregates to support the railroad tracks. From these beginnings, the company has grown to be a significant producer of aggregate and asphalt.
For more information, visit www.jslane.com.
About EESSCO
Formed in 2001 by experts in the aggregate industry, EESSCO provides New England producers with equipment, parts and consulting. EESSCO represents major manufacturers of aggregate equipment and stocks parts in its facility in Hanson, Mass.
For more information, call 781/294-8888 or visit www.eessco.com.
About Fisher Industries
Fisher Industries serves all aspects of the aggregate processing industry — from the design and fabrication of aggregate equipment, to processing and end use of aggregate materials.
For more information, call 800/932-8740 or visit www.fisherind.com. CEG
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