Inside a Knife River crushing operation

By |  March 16, 2018

The Angell Quarry, an aggregate supplier in Portland, Oregon, should be positioned for additional growth as soon as the local economy shakes off its post-recession malaise.

The quarry, which belongs to Knife River Corp., invested in an Elrus portable crushing plant to take advantage of an expected surge in aggregate business. The plant consists of a Sandvik CJ412 jaw crusher and a Sandvik CH550 high-speed cone crusher.

The company selected this plant in part because of its portability. When set up, the compact, portable units are a good fit for the quarry’s relatively limited space to process and stockpile aggregate. Also, if winter rains influence the quarry like what the site experienced two Decembers ago, the compact crushing plant can be relocated to produce aggregate at different sites.

The plant at Knife River’s Angell Quarry includes a CJ412 jaw crusher and a CH550 high-speed cone crusher – both from Sandvik. Photos courtesy of Sandvik Mining & Rock Technology

The Angell Quarry is particularly vulnerable to seasonal storms because the site has high clay content and is situated just south of a major waterway – the Multnomah Channel, a distributary of the Willamette River. Last winter, Knife River had to move its plant to the company’s Coffee Lake Quarry south of Portland.

“Angell is a very challenging quarry,” says Lynn Gullickson, aggregate operations manager of the metro division at Knife River. “Winter is especially challenging, with flooding all around. Sometimes we need to move units quickly.”

The company and market

Angell Quarry is just one slice of Knife River Corp., which controls an estimated 1.1 billion tons of aggregate reserves. In the Northwest, its customer base includes contractors working on highway construction, housing developments and government projects.

Its customer mix varies as the economy moves through different stages. Several years ago, it was focused on government contracts. However, this is not the case today.

“With the drop of state and federal funding, our customers became mainly privately owned projects,” Gullickson says. “Portland is one of the last areas to be rebounding from the recession, mainly seen right now in housing startups, so these are interesting times. But there is predicted growth in the next four to five years. We want to be known as providers of choice to all customers in the metro area.”

During summer months, Knife River quarries can overproduce their basalt cubical product and stockpile the processed material against the winter slowdown. Throughout the busy season, the portable crushing plant can add production to the company’s existing crushing plant.

“We don’t have much production area at this location,” Gullickson says. “The crusher’s small footprint gives us more stockpile room so we can reach our goal of stockpiling for winter.”

The company also seeks to have four or five years of good production before making an investment, according to Gullickson. The portable units allow the quarry to accommodate expected market growth without the company prematurely making a larger capital investment in a large stationary plant.

Environmental perks

Photo courtesy of Sandvik Mining & Rock Technology

According to Elrus’ Mark Tormey, the system takes up a smaller footprint yet offers more efficient screening with two crushers.

Knife River views managing the environmental impact of its mining operations as a way to give back to communities. In this case, purchasing equipment that minimizes the environmental disruption was paramount.

The new cone crusher helps to achieve one of Knife River’s core values, which is to minimize the environmental impact of aggregate production.

“The Sandvik CH550 high-speed cone has no plastic backing to hold the liners in place,” says Stephen Dobler, sales manager at Sandvik Mining & Rock Technology. “Furthermore, the crusher has the highest energy efficiency classification, which minimizes carbon dioxide emissions from the diesel generator per ton of aggregate produced. Also, the cone crusher produces less dust compared to the site’s existing crushers.”

The reduction in dust and noise in the crushing operation was improved, as well. With the Elrus platform, Angell Quarry produced more product than the existing spread with less equipment, a smaller footprint and a smaller, but more efficient, screening area with two crushers.

“Now with just two crushers, Angell Quarry is meeting higher production numbers and producing the same high-quality [cubical] aggregate,” says Mark Tormey, Oregon-Washington-area sales representative for Elrus Aggregate Systems. “It is doing more with less. This is a huge cost-per-ton advantage.”

Tormey put together Angell Quarry’s portable crushing plant. Elrus has been a Sandvik equipment distributor for about 25 years, and it incorporates Sandvik units into its portable common-level plant designs.

Angell Quarry received some help in its crusher operation upgrade from Tormey and Barry Proctor, senior Elrus sales representative in the United States, Gullickson adds. The quarry experienced a recent transport incident in which the feed conveyor on the cone crusher was accidentally damaged.

“Within a couple of hours all the parts were ordered and they were shipped to us ahead of schedule,” Gullickson says. “That could have been a long, dry process if we hadn’t had good support. They were there to help us. Elrus was a co-partner in the process.”

Safety minded

Knife River, a top aggregate producer in the U.S., stresses safety for its 5,000 employees across 15 states.

By investing in a portable crushing plant, Knife River believes it has created a safer working environment. Gullickson notes there are fewer people on the ground now during operation. Also, the CH550 high-speed cone crusher is sealed and features few moving parts. Fewer moving parts translates to less maintenance, making it a safer piece of equipment, he adds.

The Elrus portable plant also incorporates guardrails and catwalks that make it safety compliant for Mine Safety & Health Administration regulators. Furthermore, the common-level design and fully integrated conveyors of the portable units allow for quicker setup and teardown.

Elrus’ portable plant design for Angell Quarry includes a centralized power van and tower where an operator can oversee and control the entire crushing operation from the safety of an elevated, climate-controlled room. The central tower is a key part of the Elrus plant’s design.

Photo courtesy of Sandvik Mining & Rock Technology

From left: Mark Tormey, territory sales manager at Elrus Aggregate Systems; Barry Proctor, senior sales representative at Elrus; and Stephen Dobler, sales manager at Sandvik Mining & Rock Technology.

The control tower experience is enhanced by Sandvik’s ASRi control system. The system automatically adjusts the CH550 high-speed cone crusher to variations in material feed conditions in order to maximize production and protection of the crusher.

According to Kirk Myers, Angell Quarry site supervisor, plant operators quickly comprehend the ASRi system.

“The simplicity of the Sandvik CH550 means there is less to watch and that makes it easier on the operator,” he says. “With the ASRi system, you are able to react quickly if you need to. “Once you get used to the ASRi system, you know where to set your cone to meet specs.”

The CJ412 and CH550 connect to the rest of the Elrus platform via hydraulic onboard conveyors for ease of setup. The jaw employs electro-hydraulic wedges to change settings so an operator can respond swiftly to different feeds or production needs.

“The common-level design pioneered by Elrus eliminates the need for excess conveyors to connect each piece of equipment, reducing your footprint and allowing for significantly faster setup times, also having the option to make adjustments with both crushers via the push of a button,” Tormey says. “It requires only a few minutes. And it’s safer.”

According to Gullickson, the quarry’s transition to the CJ412 and CH550 crushers on the Elrus platform occurred without compromising quality.

“There were no gradation issues with these plants at all,” he says. “The equipment produced on-spec aggregate from the very first day. Customers are very happy and that’s the ultimate test.”

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

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