“DRIVE-BY-CRUSHING”

Aug 31, 2006

Mobile crushers add opportunity for drill-and-blast contractors and value for customers

Idaho was the third fastest growing state between 2004 and 2005 according to the United States Census Bureau. The state’s capital, Boise, is growing at an impressive rate despite the fact that the region’s geology is far from ideal for new construction. Boise – and most of the state – sits on massive deposits of vesicular basalt that come to the surface or are covered by a thin layer of topsoil. Almost all new construction in the region involves some method of rock removal.

Jerry Dilley, president, Superior Blasting Inc., and Dan Lafferty, president, Dan Lafferty Construction, Inc. share a common goal: drill and blast rock to make way for new construction. Both men blast on jobs ranging from private subdivisions and public roads to massive agricultural spreads for Idaho’s burgeoning dairy industry. They’ve seen many of their competitors using alternative methods such as sawing and trenching to remove rock from the region. In order to stay competitive and provide a greater “value” of service to their customers, the two men joined together to purchase mobile jaw crushers that have helped add value to their services and stay ahead of the competition.

Crushing Brings Balance to Construction Site, Costs

In the old days, Superior Blasting and Dan Lafferty Construction were simply responsible for drilling and blasting rock for new construction: drill down to the proper depth, install and ignite the explosives and move on to the next job. The general contractor in charge of the site was left with piles of shot rock that had to be disposed of and had to find aggregate to bring back in as fill. Importing and exporting is an expensive business (trucking, material and labor costs) and both men knew they could help their customers save money. To accomplish this they purchased a Komatsu BR350 mobile crusher from Modern Machinery in Boise five years ago. The men added a brand new, 180 HP Komatsu BR380JG-1 to their partnership in 2005.

“It got to the point where people weren’t taking rock anymore or were charging to get rid of it,” says Lafferty. “And getting a hold of aggregate in south central Idaho is tough. The beauty of the crushers is that you can get into mass excavation, knock that stuff down to compactable structural fill and help the site balance and get rid of the import/export issue of trucking. That’s where these crushers really shine is in helping to balance the site. Both of us saw the crushers as a way to make our businesses more competitive by getting rid of the waste issue and by making an unusable product useful.”

Potential uses for the crushed rock include 3-in. minus as sub-base for road construction, 3-in. minus as engineered backfill for new construction, and class 1 rip rap (8-in. minus) for ground cover along highways. Both companies typically crush waste rock down to 2-5-in. material – a practice that has nearly eliminated the problem of waste rock.

“People will come and get it,” says Dilley, “as long as you crush it down to something they can use.”

Furthermore, both crushers have the ability to remove soil from the crushed rock through a self-contained separator and muck conveyor. The self-designed, custom dirt belt on the BR350 and the factory-installed (optional) muck conveyor on the BR380JG-1 have helped provide optimum use of all material blasted by their companies, often leaving nothing behind.

“We need to pull that dirt out of the crushed material to make decent compactable base for any kind of structure-bearing surface,” says Lafferty. “We’re extremely careful about keeping the rock and dirt separated. If the crushers couldn’t do that, we probably wouldn’t be using them.”

“The dirt belt runs about 75 percent of the time that the main discharge belt is running,” adds Dilley. “Topsoil is very precious in our part of the world. When we go in and drill and shoot an area we leave the topsoil on. It helps contain the flyrock, but the contractors would like to get that topsoil back. Normally (without a muck conveyor) it would go to waste. We did one job in Boise where the topsoil coming off the conveyor was worth $11 per yard and the rock was worth about $3 per yard. The landscapers love it because it has already been worked and it has a little bit of granular material in it so it percolates water perfectly.”

Recycling Concrete and Asphalt – and Past Customers

With the explosive growth of the dairy industry in Idaho, Lafferty and Dilley have used the crushers extensively on sites to blast rock to make way for new dairy barns and underground utilities such as manure handling systems and bio-lab chambers. The expansion of the dairy industry has meant changes in the way farmers do business, which has also created a unique opportunity to recycle concrete.

“A lot of these agricultural areas are going to pivot irrigation rather than regular gravity irrigation,” says Dilley. “So there have been thousands of feet of concrete ditch (used in gravity irrigation) that have been ripped out. Both of those crushers eat concrete. It just bores through them.”

Lafferty adds that they typically crush the concrete down to a 2-in. minus material that makes a perfect base for erosion-resistant roads and driveways on farms. A factory-installed magnetic separator ensures that no scrap steel or rebar gets in the mix. In addition to recycling concrete on these new projects, Lafferty reports that he has used the crushers to clean up worksites for former customers.

“We’ve actually gone back and cleaned up shot rock that we blasted 15 years ago,” says Lafferty. “We’ve gone back to several of these sites and crushed 3-in. base for them to do additions or to build roads out to their irrigation projects.”

The crushers have also proved effective for “off-season” projects such as recycling asphalt (ideal in winter due to the oil content in asphalt and the heat generated by crushing) and concrete washout at concrete plants where the need to recycle the aggregate it contains is high.

Mobile Crushers Offer Versatility Not Possible with Stationary Counterparts

The easy mobility of the BR350 and the BR380JG-1 has been an important advantage for Lafferty and Dilley. As Dilley explains, “Most of our stuff is hit-and-run – drive-by-crushing.”

Lafferty adds, “You can literally move the excavator, unload that crusher, pull a couple of pins and be crushing in 5 minutes. There is no set up time. Talking to our competitors around here – it takes them a week to set up their stationary jaw, get their gen-set out there and get all set up. And yes, their production is going to be higher, but in a week’s timeframe, we’re on the third job already. Mobility of the crusher is where it really shines.”

The “mobility” of each crusher extends beyond the ability to move from site to site. Featuring the undercarriage of a Komatsu hydraulic excavator, each crusher can easily tram from pile-to-pile, which eliminates costly “second handling” of material.

“It will tram along the side of a trench while an excavator excavates the rock and throws it right into the crusher,” says Dilley. “People would worry about having to pile rock up because it costs money to second-handle that rock. We’ve been able to say ‘leave that rock where it is and we’ll get to it.’ The fact that the tram-ability of the crusher is almost as good as the excavator means that we rarely have to have a dozer out there building a path. These things will climb a mountain.”

“The center of gravity for both machines is good,” adds Lafferty. “They’re not tippy at all.”

Lafferty also points out that the radio remote control – a new feature on the BR380JG-1 not available on the older BR350 – has been a major boost to mobility and operator awareness because the operator does not have to be on the crusher constantly.

“Instead of being on top of the crusher and not being able to see the ground,” says Lafferty, “the guy on the BR380JG-1 with the remote control can walk around it and look under it as they move it into position without causing any damage. Otherwise it would take a spotter on the opposite side of the machine on the BR350 to make sure no rocks or hazards cause damage to the machine.”

Crusher Technology Advances Boost Productivity, Simplify Service

Lafferty and Dilley have put more than 7,400 hours on the BR350 since they bought it five years ago. The machine still has its original hydraulic pumps and undercarriage, and features all the same basic controls and functions as the day they purchased it – only high wear items such as the jaw linings have been replaced and/or rebuilt.

“The reason we looked so hard at (purchasing) the BR380JG-1 was the durability of the BR350,” says Lafferty.

“And since we bought that BR380JG-1 in July,” adds Dilley, “we’ve got over 800 hours on it. It’s very popular.”

According to Dilley and Lafferty, the BR380JG-1 will crush almost twice as much 2-3-in. rock as the older BR350 thanks to a larger jaw. The BR380JG-1 features the largest jaw in its class, a load-presetting semiautomatic feeder system and an increased crusher rotation speed – all factors that enhance crusher efficiency. Lafferty estimates that the BR380JG-1 will crush anywhere from 100-125 tons of 2-3-in. rock per hour and that the BR380JG-1 and BR350 feature similar outputs with larger stone over 6 in.

“The larger jaw is nice,” says Lafferty, “because we can throw a larger rock in the hopper and clean up the site a bit better. If we can’t get a rock in the crusher then we have rock hammers that will break the larger boulders down. But even on a drill-and-shoot job it will get 90-95 percent of the rock.”

The jaw systems also have advanced to make the removal of clogged material easier and the recalibration of the jaws as simple as the touch of a button. While most jaw crushers (including the older BR350) protect themselves by bending toggle plates when jammed, the BR380JG-1 protects itself by allowing the locking cylinders to fully open the discharge port.

“The fact that you can open the jaw with just the push of a button has saved us a lot of time,” claims Dilley. “If you get a big rock turned the right way (in the BR350) the jaw simply won’t take it – the rock will just sit there and ride the plates. With the BR380JG-1 you just walk up to it, push a button and the jaw opens and the rock falls out. You push it again and it comes back to where you want it to be. That process is a 30-minute ordeal with the BR350.”

“Being able to recalibrate the jaws is excellent, too, as far as jaw wear goes,” adds Lafferty. “It readjusts itself to a preset setting. We are adding shims manually with the older BR350 to get the size we are looking for. On the BR380JG-1 the jaw actually comes down and touches at the bottom, sets at zero and recalibrates from there.”

In terms of general maintenance and greasing, Lafferty and Dilley service both machines in the field and appreciate the added accessibility to major service points on the BR380JG-1. And while they haven’t had to use it, both Dilley and Lafferty appreciate the fact that many key components (filters, etc.) of the crushers are interchangeable with their PC200 excavator.

“The BR380JG-1 is a lot easier,” says Dilley. “It’s light years ahead – you can actually get to the bottom of the jaw in the BR380JG-1 just by crawling through one of the inspection holes. There’s much more room underneath the BR380JG-1 (for access) than there is (underneath) the BR350.”

Conclusion

Dilley and Lafferty have done something most competitors wouldn’t do: team up to provide their end-users a service that offers them the optimal use of the natural resources on their sites. By commissioning mobile crushers like the BR350 and the BR380JG-1, both of their companies have reached new heights in customer service and productivity. And in a region surrounded by nothing but rock, neither man will see the workload of his crushers decrease.