Aggregates Manager Digital Magazine
Issue link: http://read.dmtmag.com/i/732024
AGGREGATES MANAGER / October 2016 13 zation established by trucking leader J.B. Hunt, American Aggregates serves as the U.S. arm of a Honduras-based mining operation. According to George "Chip" Doll, Jr., the company's terminal quality control manager, Hunt's ratio- nale for purchasing a mine in Central America was both sound and prescient. Despite a 2010 ruling reaffi rming mining rights in Florida's productive Lake Belt region, reserves from other parts of the state are being heavily tapped, all at a time when demand for limestone is on a steady rise. In addition, a recent study shows the state's overall demand for aggregate rising from 76 million tons in 2010 to more than 126 million tons in 2030, with better than 95 percent of that material eventually being imported. "Unlike the material generally found in this area, the limestone we bring in from our Honduras mine is extremely hard, which is what our customers need," Doll says. "Florida doesn't have a lot of hard rock left in its reserves, and with development once again on the rise, the demand for such a product is huge. So we, as well as some of our neighboring companies here in the Port, regular- ly bring in rock from Central America, Mexico, Canada, etc., and sell it for use in road-building applications, as well as in the production of asphalt and concrete." Take a load off At the Honduras location, the newly mined limestone is processed and graded to a number of sizes, including screenings/manufactured sand; #89, which is a 3/8-inch rock; and #57 or 1-inch material. It is then loaded into segregated holds of a transport ship for a three-day trip to the Port of Tam- pa. Upon arrival, the self-unloading vessel conveys its cargo to a portside hopper which meters and regulates the volumes of material loaded into a steady stream of dump trucks passing below. Once loaded, each truck heads to a nearby 25-acre stockpile area. Getting the ship unloaded in a timely manner is critical, according to Doll. "There's an issue called 'demur- rage,' which is essentially a penalty for exceeding the time it should take to offl oad the ship," he says. "And the clock starts running as soon as the ship is docked, so if any kind of breakdown occurs and the allotted time is exceed- ed, those costs can add up quickly. I'd say that's as good an incentive as any for a company to have a system in place that they can rely upon." Up until about two years ago, Amer- ican Aggregates contracted with a fi rm to handle the transfer and stockpiling of the limestone cargo. While effective, the process was hardly economical. "Suffi ce it to say that we were paying a lot of money per ton for that service," Doll says. "And considering that the shipments we get in vary from 55,000 to 60,000 tons each, it's easy to see why management start- When ships arrive from Honduras to the Port of Tampa, American Aggregates, LLC, unloads up to 70,000 tons of limestone.