Put elements that can improve production at the finger tips of a trained operator and productivity is sure to go up.

by Scott Ellenbecker

Conco Quarries Inc., a high calcium limestone quarry in Springfield, Mo., recently became the first U.S. operation to use a ROC F9C SmartRig. It put the drill into production to better manage its explosive scheduling and costs, but found additional benefits along the way.

A SmartRig is a rock drill with automation features, including a global positioning satellite (GPS) system used to direct hole placement. Other automation features include operator screens that indicate drilling functions and auto drilling that does everything from add steel to a pre-programmed depth to manage drilling speed so the bit doesn’t get stuck.

In Scandinavian countries, especially, the SmartRig concept has been working for years. In Norway, for example, all construction shots are laid out on computer and published on the Internet prior to doing a project. This is meant to elevate the level of safety because all blast material placements are planned in advance. In the United States, construction projects don’t currently require this level of design. Here, the advantage is saving costs and time associated with drilling, crushing, and moving rock.

When planning production schedules, Conco knows how much rock it needs and of what chemical composition. To lay out a shot well in advance gives management the time to plan ahead because the pattern isn’t painted on the ground, but rather electronically taken from a computer. That data is transferred to the computer in the drill. The rig can work with a foot of snow on the ground; it doesn’t matter to the computer.

“The goal is to lower our drilling costs and give us flexibility when laying out a pattern,” says Chris Upp, Conco’s director of quarry operations. In the months since introducing the rig, Upp says, “We have reduced drilling costs 10 to 12 percent, and we are continuing to see drilling and blasting costs go down.” He says he expects it will take six months to get a picture of the long-term savings associated with the rig.

When looking at costs, Upp looks for the optimum breakage on every shot. “If it isn’t perfect, you pay for it later,” he notes. He points out that Conco’s crusher can take a 60-inch cube, but that is not efficient. “You walk a fine line with your costs: oversized rock is bad for equipment and too much fines means you’re wasting money on explosives. With the GPS, you’re right on the money and you don’t miss,” he says.

In the next few months, Conco will continue to test burden and spacing to optimize its shot pattern. Currently, it drill 4-inch holes with T51 steel in a 9-foot by 13-foot by 27-foot pattern. Upp says the rig currently drills 2,200 to 2,800 feet per day, and the site blasts twice a week. Upp’s goal is to have 100,000 tons drilled and 80,000 tons on the ground all the time.