New order: Renewing a crusher lineup

Replacing a broken crusher made a big difference for the Lafarge Pitt River Quarry. Rethinking the operation’s existing crusher arrangement made an even bigger difference.

Operations at the Lafarge Pitt River granite quarry in British Columbia, Canada, were running smoothly enough in 2013, churning out about 990 tph of high-quality aggregate used in Superpave, asphalt and concrete applications.

When a mainframe cracked on a 54-in. cone crusher, Quarry Manager Robert Brakes sought bids to replace the quaternary unit, which was too old to warrant repair. Brakes ultimately weighed four replacement offers.

Among the finalists was Elrus Aggregate Systems, a Sandvik Construction dealer for western Canada, which supplied the quarry’s secondary crushing unit – a Sandvik S6800. Elrus representative Mike Wikdahl believed a common platform unit to the S6800 – the Sandvik CH660 stationary cone crusher – would be a perfect addition to the crushing system. After he studied the company’s operation, Wikdahl went one step further.

“We initially offered what our customer requested – a straightforward replacement of the quaternary crusher,” Wikdahl says. But after studying several flow sheets, Wikdahl proposed that the quarry rearrange its lineup of machines to take advantage of the CH660’s finer product output. Specifically, he suggested the company’s tertiary crusher be relocated to replace the broken cone crusher and the CH660 replace it in third-stage crushing. He predicted an increase in production of at least 10 to 15 percent from the added capabilities of the CH660 compared to the existing solution.

Brakes pored over the flow sheets, bringing to his analysis the perspective of a third-generation quarry operator with 27 years of experience in the industry. He recognized that Wikdahl had done a lot of research, but, he says, “It still took me a little bit to read between the lines.” In the end, Brakes came to the same conclusion: placing the new crusher in the third position in the crushing sequence would boost output. That has proved to be the case.

“The CH660 produces aggregate of a good size for the next stage of crushing,” Brakes says. “Now the quaternary crusher isn’t dealing with 4- to 4.5-in. rock, but with 2.5-in. rock. The result is no plug-ups and a good flow.”

Production increase

Quarry Assistant Manager Shayne Daum agrees size reduction turned out to be “a bigger thing than we thought.” He says Wikdahl’s analysis showed clearly that the existing tertiary crusher produced an operational bottleneck as 4- to-9 in. crusher feed would overflow and be dumped to the ground, requiring additional handling.

“With the CH660,” he says, “the unwanted byproduct has gone from a thousand tons a day to zero.”

The CH660 went online in January as a tertiary crusher, and the benefits to the Lafarge Pitt River Quarry have been impressive. The most obvious one is the sizeable upturn in total production: The quarry experienced a 30 percent increase in aggregate output, reaching about 1,300 tph. The increase was double that predicted by Wikdahl.

“Before, it was hard to hit [1,100 tons],” Brakes says, adding that “the cost per ton was the deciding factor. We typically were running a shift and a half to get the same tonnage as we now are doing with regular shifts. That’s huge when you add it all up: wear on belts, fuel, manhours and other costs.”

Maintenance scheduling

Another advantage for the Lafarge Pitt River Quarry is better maintenance scheduling. Because of increased production rates, the quarry can afford regular planned maintenance interruptions, which also avoid costlier overtime repair work.

“Before, we had to run around and chase maintenance needs,” Brakes says. “Now we can plan on scheduled maintenance programs.”

Systematically maintaining the machinery has other positive implications for the company. Because the maintenance occurs regularly, budgeting for it is regular, too. The cost is spread throughout the year rather than coming in surges at sometimes inconvenient times.

Also, the CH660’s design adds to the positive maintenance news. According to Pitt River Crusher Operator Nolan Wall, changing out the liners is easier and faster, which is significant because “downtime is a killer.”

The CH660 liners are also more durable than on the crusher the unit replaced. According to Brakes, liners on the previous crusher lasted 650 hours on average.

“Now we are getting a couple hundred more hours on a liner,” he says.

Stephen Dobler, Sandvik Construction’s business line manager for crushing and screening in Canada, says the CH660’s CLP manganese liners perform better overall because they are engineered to maintain intake capability and chamber geometry longer than the previous crushers.

The crusher also benefits from more-efficient power transfer to the crushing chamber, and from Sandvik’s Hydroset technology coupled with the ASRi automation system that maintains optimum reduction despite wear. “These features ensure a customer can maximize reduction and reduce the amount of recirculating material, freeing up space to process more material,” Dobler says. “So the performance of the crusher and the quality of the product are more consistent.”

Parts and service

Breaking rock is a tough job, of course, and components do wear out from the constant grinding and can break down over time. As the Pitt River quarry manager considered the competing solutions and bids, he points out that he did so with an eye on service expectations. “You cannot afford downtime,” says Brakes, who adds, “it can cost $10,000 an hour if you are down, so reliable after-sales service was important in choosing a crusher.”

Elrus Aggregate Systems has an office within a reasonable distance of Pitt Meadows, where Lafarge operates its quarry. That was important to Brakes.

“Elrus is not far from us,” he says. “If they don’t have a part, they typically will have it in Calgary where they are headquartered. That was a key factor in our decision.”

It also helps that the CH660 has some parts in common with the other Sandvik crusher in the quarry, the S6800. That makes it easier for the company’s maintenance department to keep an inventory of machine components on hand. Furthermore, maintenance technicians can fully access the CH660 from above to inspect critical parts, and they can service the machine with the easy access speeding the work.

Pitt River Quarry is part of a Lafarge North America network of about 900 offices and operations. The Pitt Meadows facility is a Lafarge flagship location and is located about 30 miles west of Vancouver. That places it within the Vancouver metro area, which is a big market for the quarry.

Situated near the banks of the Pitt River, it annually ships 1.65 to 2.2 tons of aggregate, loading either river barges or trucks with product. The shipments should continue for a while as the quarry has sufficient reserves to keep crushers busy for the next half century.

Take note

Liners on the new crusher last a couple hundred more hours than liners on the previous unit.

Giles Lambertson is a freelance writer (and former carpenter) who has been writing about the construction industry for nearly two decades.