May 1, 2009
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.
According to Upp, just a few inches make a difference. This is proven in the straightness of each hole as well. The high wall face shows clear evidence of the straight holes. “We don’t have a lot of back break on the high wall, and a smooth clean wall is left behind,” Upp says. This unplanned surprise also has reduced any safety issues and costs associated with removing hanging rock.
A driller’s perspective
Conco’s driller, Matt Cobb, has years of experience on a rock drill and says he was skeptical at first. “I think I’m like most experienced drillers when I say a person can do better than the computer because I can react to what is going on in the ground,” Cobb says. “And, for a time, I can drill as fast as the computer, but for how long is the question.” He said all drillers will drop a steel on occasion, but the computer never drops steel, shift after shift, day after day.
The automation function frees up the mind too. “When you’re drilling, your mind is always working, ready to react to the changing ground,” Cobb explains. “The computer on this rig allows me to think about other things and relax a bit.”
Cobb says the computer also allows him to multi-task while the drill is in operation. Once he starts the drill in auto-drill, he can leave the cab and check holes for blockage and place cones over open holes.
When the rig first arrived, Cobb ran two drills side-by-side to see if he could keep the same pace as the unit. Cobb would set up with the new rig, start auto drilling, and jump in the older Atlas Copco ROC 848 to drill a hole manually. When the new rig was finished, it would sit and wait for him to move it to the next location. He would then do the process again. “It’s not something I’d want to do for a long period of time, but it got me caught up,” Cobb says.
He says he especially likes the GPS system on the new rig. To set up the pattern, the first hole and last hole is set, and a computer extrapolates the rest. A memory stick transfers the information to the rig’s computer, and the operator just follows the screen.
“I match up the bull’s-eye on the screen with the transmitter on top of the feed, the computer tells me it’s straight or if I need to make adjustments,” Cobb says.
There are many subtle benefits as well. Because of elevation changes in the quarry, Upp said the drill has allowed the operation to flatten out benches. And because the hammer adjusts with a split second to the ground conditions, it is more efficient and less stressed. The computer also monitors maintenance schedules to keep the rig running at peak performance.
Conco works with Atlas Copco distributor Victor L. Phillips for service and training. Since startup, Upp says they have had no downtime, but that comes with good training and regular preventive maintenance.
Dave Ferson, corporate sales manager with Victor L. Phillips, said that the drill’s advanced technology caused some apprehension for both the operator and the distributor, but their concerns were overcome by the simplicity of training and the unit’s strong design.
Jeremy Riley, Phillips’ field technician, says the drill is much easier to work on than conventional drill rigs due to its self diagnostics, as well as a 30-percent reduction in the use of hydraulic hoses and electrical wiring.
Because of an onboard GPS system, the manufacturer and distributor support the rig 24/7, monitoring pertinent drill information through data downloads to laptops. “The technology on this rig reduces the workload for the operator when drilling, but also helps everyone work smarter,” Ferson says.
Overall, it will take time to know the total financial benefit of the drill, but Upp says he can already see differences. “I had to sell the owners on this rig because it was more expensive,” he says, “but it’s clear that the savings we have seen in productivity are offsetting that difference.”
Scott Ellenbecker is editor-in-chief of two in-house publications for Atlas Copco: Deep Hole Driller and Mining & Construction USA. He has been involved in marketing construction and mining equipment since 1995.