Por: Rodney Garrett (Seen in Pit and Quarry Magazine, 01/2006)


Texas Sports Sands relies on VSI crusher technology to turn pea gravel into white sand.


Those fortunate enough to be mining white rock for manufacturing sand know its value in the marketplace. There are others, however,who have access to such rock but do not have the knowledge to process it cost-effectively into sand. Needless to say, there is little
to no incentive to make sand if it is not profitable. So cost-effectiveness is key.


Some sand-production companies have taken a significant step by turning pea gravel that had no resale value into sand products that command a premium price.To illustrate,Texas Sports Sands Inc. of Kosse, Texas, is mining sand in a four-acre pit on a 225-acre mining site. The bottom of the pit is currently 100 ft. below grade. Since the pit is covered with 20 ft.of ground water, a floating dredge is being used for mining and pumping the sand and gravel to grade,where it is screened.


A major change has been made to the sandproducing plant by Texas Sport Sands with the addition of a Rock Engineered Machinery Co. Inc. (REMco) SandMax VSI crusher. Before the VSI crusher addition, salable sand was limited to 75 percent of all the materials mined. The rest of the stone was classified as pea gravel (oversize) so it was stored in great mounds with no marketable use for it.



Meeting the concern

Mining sand annually at a rate of 200,000 tons since 2001, Keith Blair, president of Texas Sport Sands, was becoming concerned about the everincreasing
stockpile of nonsaleable gravel. He says, “I would have gladly given it away if anyone
could have used it, but that never happened. I could not find a market for the pea gravel and I was concerned about the storage area it was taking up at the site. The more I
dredged, the higher the storagepiles were becoming.”


Last year, Blair contacted REMco to find out whether one of the company’s VSI crushers could cost-effectively reduce the pea gravel to saleable sand. He sent a barrel of the gravel (which is 99-percent silica) to REMco so the engineers could test crush it in the laboratory for its feasibility. “We test a client’s rock or gravel through our test plant where we use a full size REMco SandMax unit,” says Damian Rodriguez, general manager of REMco.


“That way we achieve a representative performance that is the basis for our crusher
recommendation.The testing determines how REMco manipulates the crusher design
variables to achieve a custom effect to meet the producer’s needs.” For Texas Sport Sand, the test results were positive. Not only could a REMco VSI crush the gravel, it could do it efficiently and at a low cost. The VSI crusher recommended by REMco was the
Model 200 SandMax VSI crusher powered by a 200-hp electric motor.


Marketable product

With this VSI added to the sand-processing line, 100 percent of the materials mined could be converted into various marketable sand products.All the mined
materials are still run through a wet 6 x 16 double-deck screen for separating the
useable sand from the 25 percent (pea gravel),which had no marketable worth.

The scalped pea gravel is now sent through a 36-in. dewatering screw and
scrubbed to remove the clay balls. From there it goes to a surge bin for supplying
the VSI crusher. Depending on the coarseness of the pea gravel, the crusher’s
throughput ranges from 100 to 150 tph.


The VSI crusher is in a closed circuit for returning the oversize gravel to be recrushed
to wanted size.Blair says 60 percent of the gravel fed through the VSI crusher meets the sand specifications after the first pass. Accordingly, here is the bottom line: Fifty-thousand tons of additional white sand is annually produced by the VSI crusher that previously was being stockpiled as worthless pea gravel. The revenue brought in by Texas Sports Sands on this extra sand is $50 per ton, with most of it being marketed in Texas, Oklahoma and Louisiana. That is a $2.5- million increase in annual sales resulting
from adding the SandMax VSI crusher to the sand production line.


Premium price

The premium price paid for this sand is paid by those using it for golf course bunker sand because of its whiteness and its penetrometer-value rating. The lower the ball-lie rating, the higher the penetrometer value, which is expressed in kg/cm2.Any value greater than 1.8 is considered acceptable by most golf courses so it is easy to understand why Texas Sports Sands crushed-sand penetrometer value of 3.2 is outstanding and sought after.“We sell much of the crushed sand because of its high value for bunker sand. Our
crushed sand is the highest-rated bunker sand in Texas. The mined/screened sand
has a value of only 2.2 and does not bring the same premium price,” says Blair.


The reason the VSI crushed sand has the more desirable low-ball-lie rating is because of its angular shape when compared with the mined/screened sand that is more rounded in shape. Simply, the golf ball sinks deeper into the sand when the sand grain shape is round (as opposed to angular).


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