Por: Charlie Denn (Seen in Construction, 06/1995)


It all started when changes in Federal requirement concerning the composition of concrete used on many jobs reduced the need for gravel in the mix.


Any business can prosper when times are good. But a big key to survival when the economy is a little slow is the ability to be innovative. That’s exactly what officials at Seven Star Aggregate, a LaPlata, MD-based sand and gravel manufacturer did recently. The chance they took has been paying off in a big way.


It all started when changes in federal requirements concerning the composition of concrete used on many jobs reduced the need for gravel in the mix. The federal mandates stressed the use of bluestone instead of regular gravel, leaving suppliers like Seven Star in something on a lurch. Rather than sit on his gravel stockpile, Seven Star vice-president Tom Miller looked for a way to make the gravel useful again.


He eventually bought a REMco SandMax 800 VSI crusher from Kemper Equipment. The SandMax fine crushes the gravel and produces a spec C-33 sand. The sand, which a high strength material, can then be sold as a raw product to concrete and asphalt manufacturers and is used in the production of new mixes.


“Our major commodity was sand,” said Miller. “Yet we had about 200,000 tons of gravel on the ground which had been used in the production of concrete. ”Then when the specs where changed, we had to find something else to do with our gravel,” Miller added. “We bought the crusher because we decided we’d rather have some money in our pocket instead of on the ground.”


The REMco crusher is fed by a loader which scoops up the gravel from a nearby stockpile. The gravel is crushed into minute particles and produces pea stone No. 67 gravel and sand.


The machine is an autogenous vertical shaft crusher designed to operate as a third or fourth stage crusher in processing rocks, ores, and minerals. It is designed especially for sand products.


The RockMax 8000 has a maximum horsepower rating of 250. It utilizes a V-belt drive system and the maximum feed size of material is tow and a half inches. Miller estimated the crusher is producing about 100 tons of sand an hour.


“Sand is selling,” he said. “This way we can turn our gravel into a product which is profitable for us. Concrete and asphalt producers are able to put this right in their mix.” When Miller was searching for a crusher to fit his needs, he looked at several models, settling on the SandMax because he believed it was the right machine for the job.


“I liked the machine right away,” said Miller. “And the Kemper people were great to work with. They told me to try the machine for a while and if it didn’t do what they said it would do, they’d take it back and I’d own nothing but the cost of freight. “It worked well from the start,” Miller added. “We’ve liked it from day one and it’s added an important aspect to our business.”


Greg Donagher, who sold the machine to Seven Star, stressed the economy of the crusher. “We wear-cost guaranteed they could produce sand at 11.4 cents per ton,” said Donagher. “They’ve found now that they can produce sand at about six cents per ton.”

The REMco crusher, which manufactured in Livermore, CA is 100 percent U.S made. It features an automatic lubricating system, a crusher drive adjustment and is clean and dust-free during operation. Other features include a side inspection door and a worker-friendly drive guard system.


An important benefit of using the REMco machine is that it produces cubical shaped particle aggregates. In mixing concrete, test have shown that cubical aggregates give greater workability in placing the mix, easier and faster finishing and less cement required per yard for a given strength.


Higher strength aggregates also yield higher strength for a given content and result in less water required to achieve a given slump. Better mixing of ingredients also result.
Miller estimated his company sold roughly half a million tons of sand last year alone. The new crusher has helped Seven Star meet its increasing demand for this important product.


“We’ve been very happy with the crusher,” he said. “It works constantly because we always have the need for more sand. “Even when the job specs change and gravel can again be used extensively in concrete and asphalt, we feel this machine will remain an important part of our operation,” Miller Added.


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