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New screening system enhances efficiency, lowers costs

By |  July 7, 2014

In part one of a two-part feature, a Canadian sand-and-gravel producer tests a new screening system amid intense market pressure.

Downtime is lost opportunity and profit in the fast-moving oil and natural gas fields of the Peace River region, located in northeastern British Columbia. The boom there is pushing companies like sand-and-gravel producer Nels Ostero Ltd. to produce more – and faster. To keep up, Nels Ostero needed to beef up its screening.

“Over the last three years, the demand for aggregates has really taken off,” says Nilson Ostero, the company’s manager. “The area’s infrastructure is rapidly growing, so there’s tremendous pressure to keep up with local aggregate demands.”

Nels Ostero, a third-generation company, has used W.S. Tyler screens since its first years in business. Although Ostero was pleased with the screens’ wear life, the company occasionally experimented with lower-cost screen media. He discovered some significant differences.

According to Ostero, some screens lasted just 30 percent as long as the wire cloth to which he was accustomed. The quick wear forced the company to change screen panels about every three days – much too frequently, Ostero says, adding that the premature failures cost the company downtime, production and thousands of dollars in maintenance and labor fees.

Wire cloth was working well for Nels Ostero and providing longer life, but changeouts were still required too often on the feed end of the washing screens – up to four or five times per year for each screen, according to the company.

Searching for solutions
Washing screen changeouts are time- and labor-intensive tasks. The confined space with spray bars and the amount of rust that forms on the material make a changeout challenging.

Ostero says washing screen changeouts are the least favorite job among his team. While four employees can change the screen media on a typical vibrating screen in just two hours, the feed end of a washing unit can take the same four employees up to two shifts to complete. That’s a $3,000 expense in labor alone, he says.

According to Ostero, the entire plant needs to shut down while installing the new screens, making lost production obvious. Ostero says the drainage gravel and concrete sand the company produces ranges from $17 to $26 per metric ton. With varying output rates, two 10-hour shifts of downtime can be crippling, easily costing the company more than six figures per changeout in production time lost.

Ostero figured he’d have to live with the expenses and the hassle, but he no longer does. W.S. Tyler opened its Haver & Tyler Rocky Mountains facility in Chilliwack, B.C., on the outskirts of Vancouver, B.C. The new location put the company’s technicians and specialists closer to companies like Nels Ostero so they could respond quicker to investigate problems and find solutions.

Markus Kopper, Haver & Tyler’s general manager, contacted Ostero and offered to visit the site to inspect each of the machines at no cost. The visit included a complete vibration analysis, which is a part of W.S. Tyler’s Pro-Deck approach; full inspections of all vibrating machines; recommendations; and a Pro-Deck Efficiency Report.

Ostero couldn’t refuse this offer. Kopper visited the site to perform testing and analysis on each of the machines. According to Ostero, the W.S Tyler crew worked around Nels Ostero’s maintenance schedule, trying to minimize downtime. A vibration analysis of each of the six machines revealed that five of the units were performing within normal parameters and one was in critical need of major adjustments.

W.S. Tyler informed Ostero that the particular machine was showing a high G-Force and twist factor at the center and discharge end. Furthermore, its right side plate had a crack, the lip support beam was cracked and the feed material was impacting on the screen media rather than the feed box. W.S. Tyler also suggested minor adjustments to optimize the performance of machines that were functioning normally.

In addition, Kopper recommended a change in screen media on 22 of the 34 sections of deck in the operation to fix problems with blinding, pegging, open area and excessive wear. Ostero paid special attention to the recommendations for the screen media on the washing screens.

At the time of the analysis, Ostero had Ty-Wire on the first two sections of the top deck on both screens. Ty-Wire, which is a blend of polyurethane and wire cloth, has a greater open area than traditional modular polyurethane, and the material offers four to six times the wear life in comparison to woven wire cloth. The screens at the discharge end were regular square mesh.

“In analyzing the decks of the wash screens, we felt Nels Ostero could benefit from tailoring the first section of the decks to the application and phase of screening,” Kopper says. “They needed more wear resistance and could reduce the open area to get a larger impact surface for the material. This has the potential to significantly reduce the downtime.”

Kopper recommended swapping out the first section of Ty-Wire to Ty-Max with the same size opening. Ty-Max screen media is manufactured with specially formulated polyurethane developed for optimal wear resistance, Kopper says. This media is designed to handle direct feed better than wire cloth, reduce changeouts and maximize productivity – exactly what the operation needed.

Ostero wanted to see the exact impact the new Ty-Max screen would have, so he decided to implement W.S. Tyler’s recommendation on the east screen only. Because the east and west screens are identical, this allowed Ostero to compare the wear on each to see whether the change was worth the investment.

“We already know that where we used to get 50,000 tons of material across a section of wire screens, we can now process somewhere between 100,000 to 150,000 tons after implementing the recommendations from W.S. Tyler’s Pro-Deck approach,” Ostero says.

Kopper is confident Nels Ostero will continue to see the change it needs.

“We’re excited to see the results further into this trial period,” he says. “Changing the screen media at the feed end to the Ty-Max polyurethane will give them at least double the wear life on that section – possibly even more.”

And that’s just one section.

“Based on the results of this test and the enhanced profitability, W.S. Tyler hopes to implement all the Pro-Deck recommendations on Ostero’s wash plants,” Kopper says. “We believe we can save them somewhere between six and eight days of downtime per season. Off the bat, that’s an increase of tens of thousands of dollars. You’ll see it’s going to make a big difference in the company’s bottom line.”

Laura Stoneburner is a writer and public relations specialist at Ironclad Marketing, Fargo, N.D.

Editor’s Note: Ostero incorporated the new media on its east washing screen in September 2013 and has closely monitored the performance and wear of both its washing screens since then. The second installment of this story, including the quantified results, will appear in Pit & Quarry’s August issue.

Allison Kral

About the Author:

Allison Kral is the former senior digital media manager for North Coast Media (NCM). She completed her undergraduate degree at Ohio University where she received a Bachelor of Science in magazine journalism from the E.W. Scripps School of Journalism. She works across a number of digital platforms, which include creating e-newsletters, writing articles and posting across social media sites. She also creates content for NCM's Portable Plants magazine, GPS World magazine and Geospatial Solutions. Her understanding of the ever-changing digital media world allows her to quickly grasp what a target audience desires and create content that is appealing and relevant for any client across any platform.

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