A new screen and cone crusher help a Georgia quarry achieve flexibility to meet high customer demand.

Although it may seem a little ironic, the biggest challenge faced by the Lafarge Friendship Quarry in recent months has been keeping stone on the ground.

Between the quarry’s ability to produce various sizes of crushed stone and the needs of a burgeoning Atlanta market, stone is moving out of the quarry so quickly Plant Manager Don Richards hasn’t had a chance to build up any inventory — producing just enough rock to meet the needs of a wide range of customers.

The Friendship Quarry, located in Buford, Ga., consists of more than 450 permitted acres, which yields more than 2 million tons of crushed granite each year. From rip rap to sand, the aggregates operation provides crushed rock to a number of industries, residential, and commercial builders and the Georgia Department of Transportation.

“I’d like to have about twice as much stone on the ground as I do right now, but our operation runs year round,” Richards says. “Our plan is to slowly build inventory during the winter months, but for right now, we are basically running an on-demand operation.” He credits a new plant built in March 2007 and outfitted with a Metso Minerals Model IS453 (8- by 24-foot triple-deck screen) inclined vibrating screen and HP400 cone crusher for adding the flexibility and production capability to make it possible.

Leave no stone uncrushed

With the demand for stone escalating, Richards says the operation reached a point where it was running its secondary line longer hours just to meet the demands of customers.

The operation consists of two, 12-hour shifts operated by an eight-person crew. Generally, the first shift is considered the production shift when most of the crushing occurs. Although production can continue into the second shift, the main purpose of the “off shift” is to perform scheduled maintenance.

“What it came down to is that we needed to manage our inventory better,” Richards says. “We had excess amounts of larger stone that we couldn’t reduce to the smaller sizes such as clear stone or sand. We did not have the ability to re-crush stone without running our primary or secondary plant overtime and cutting into the time we have set aside for maintenance.”

Don Richards, plant manager of Lafarge’s Buford, Ga.-based Friendship Quarry, says the new Metso HP400 at his operation is able to handle increased throughput and to quickly generate the wide range of product gradation needed at the plant.

The challenge of the project was to increase production to meet demand, while at the same time, to ease the burden on the existing operation by reducing the overtime on re-crush circuits. Richards knew the equipment used in the new plant needed to be highly flexible as well. That’s when he looked to his long-time distributor, Nor-X, and Metso Minerals to provide the necessary equipment to make it happen.

Conventional yet versatile

For this particular application, Richards specified Metso’s Model IS453 (8- by 24-foot triple-deck screen) inclined vibrating screen with MV vibrator and an HP 400 cone crusher.

Richards was already familiar with the capabilities of Metso’s IS screens. The aggregates operation has used two of them on its production lines since 2003. After consulting with other Lafarge quarries, and even some local competitors about cone crushers, Richards was confident IS screens combined with the HP 400 was the way to go for its new line.

“There isn’t a better screen for the price, and with two IS screens already in place, it made perfect sense to install another one just like it,” Richards says. “Metso has been known for rock crushing for many, many years. Again, it came down to flexibility, the HP400 is a quality product that can handle increased throughput and generate the wide range of product gradation we were looking for — quickly.”