April 2006 - The Logging and Sawmilling Journal
Keeping things Running
A recent $15 million upgrade at Tembec’s Elko sawmill in British Columbia will
deliver recovery gains, but the project was a challenge in that the mill was kept
running, with most of the upgrade work done on the weekends.
The recently completed $15 million upgrade at Tembec’s Elko sawmill in southeastern British Columbia is all about—no real surprise—producing more lumber from an existing timber supply. Just how they are achieving more yield from the upgrade and associated equipment, and how the upgrade was executed, are among the more interesting parts of the project.
It had been a while since the last major equipment upgrade at the Elko operation. In 1990, the mill was a bit of pioneer: It was one of the first sawmills in the province to install the Optimil double-length infeed system and a Sharp chain system. “We did very well with that set-up,” notes Gordon Dunwell, technical manager of lumber for Tembec. “Our Canal Flats sawmill still has those technologies and it is very competitive. It’s doing a good job for us.” The system at Canal Flats has been tweaked over the years, however. While the canter lines were originally spec’ed to do 360 feet per minute, they are now doing an impressive 600 feet per minute.
A central part of the upgrade project, the new Optimil double-
length infeed (DLI) on the small log line at the sister operation
in Elko really marks a progression from the existing DLI system.“It has quite a few more bells and whistles, such as skewing
It features an optimum rotation infeed which scans the logs and rotates them to the optimum rotation for maximum recovery. The infeed section also has log gap control, providing a consistent minimum gap between logs. The Slew/Skew/Tilt (SST) feature is designed to straighten and rescan the optimally oriented logs.
The infeed uses powerful overhead press rolls to straighten and hold the log through the scanner. It also pre-positions the log in four axes, to present the logs in the best position for chipping the four opening faces on the log. The existing two-axis optimization system has been replaced with a true shape scanning and optimizing system that is capable of handling optimum rotation, SST, sideboards and log straightening.
The four-sided canter is arranged so that smaller curved logs are “pressed” straight with pressrolls so that logs are straight sawn, but are really curved sawn. The top feedspeed is targeted at 700 feet per minute.
Completely new to the Elko operation is a twin bandmill section. These six-foot bandmills allow sideboards to be taken from either side of the cant, as dictated by an optimized solution formula. Also new are a sideboard separator section, which allows any sideboards to be taken from either side of the cant, again as dictated by the optimized solution, and a vertical gang edger infeed section that re-presses the cant straight before presenting it to the mill’s existing Ukiah vertical double arbor gang edger.
The process optimization scanning and computing system for the new set-up is from Porter Engineering.
As part of the ramping up process for the new equipment, the mill wants to work its way through to an optimum speed and recovery solution for the DLI and the bandmills. “The top speed on the DLI is 700 feet per minute, and the top speed on the bandmills is 500 feet per minute,” says Pritchard. “We want to track the recovery versus speed and determine where the sweet spot is in terms of production.”
Also new was an edger optimizer system from Coe-Newnes/McGeehee. The mill had an older CAE edger optimizer and a manual chipping edger, but they wanted to consolidate equipment, and run a single lineal edger. They installed the new 1,200-feet-a-minute edger optimizer right beside the existing equipment, having to add two building extensions to do this.
“We kept the existing edger system running right up until the last minute,” notes Dunwell.
The new edger system offers more than just speed. “The existing system had chipping edgers and we really wanted to get away from that,” says Dunwell. “We wanted to get more control over the pieces, and have them moving around less. We also wanted to get away from the positioning tables, which are high maintenance.”
The big challenge was in taking a new small log line and essentially grafting it gradually on to an existing mill operation.
The various improvements, and equipment additions, were made over a period of a year, with all the work done on weekends. Lumber prices were doing quite well at the start of the project, and the company, naturally, was interested in keeping production going at the mill, if at all possible.
That was possible, but it wasn’t easy. In hindsight, mill manager Ian Lind and his employees would have rather done a shutdown for several weeks to get the upgrade done in one go. Instead, the work was done mostly on weekends. So at the beginning of each work week—on the Sunday night—sawmill crews would be contending with various new pieces of equipment and changes in the sawmill set-up. “At times, it was like having a mini mill start-up every weekend,” says Pritchard. “The mill people are coming in and there is always something new.”
And after the weekly start-up, there was still work to do. If they had to change the speed on a drive, for example, they’d have 20 minutes at lunch time on the Monday to do the work. “It was a challenge,” says Pritchard.
While it produced some frustration, it did keep the mill operating, and mill employees, and mill manager Ian Lind, are happy with the more efficient operation they now have.
Installing a new state-of-the-art DLI system and bandmills, and associated upgrades, would normally require lengthening the line, and sawmill building. But the budget did not include such provisions, so they improvised, doing things such as building a merry-go-round back to a log ladder to provide extra length to the line. “Ideally, we would have picked up the whole log deck and moved it back, but that was outside the scope of the project,” notes Dunwell.
Along with major changes to the front end, came changes to the sort stations, lumber lines, and revisions to the trimmer infeed, with the primary goal of making sure the higher piece count could be accommodated. They went with a Comact lugfeeder system in the trimmer infeed area, being quite impressed with Comact’s style of backlog control. Because they were changing lumber lines as the project proceeded, Comact built them a special lug loader that was essentially ambidextrous. It started with handling lumber on one side and, when the new equipment kicked in, switched to handling it from the other side.
Other new equipment included a hydraulic linear positioner and a new three-stage fence from Mill Tech Industries. Mill Tech also helped them change the lumber line through the multi-saw trimmer, and made a number of other modifications as the project proceeded. Softac changed the handling on the trimmer optimizer scanner.
Three additional decks on variable frequency drives were installed to handle the backlog. Installing the decks meant moving the unscrambler back, which was a big job in itself.
Each deck is controlled separately to close any gaps, explains Dunwell. “The idea is when you get pieces to the lug loader, they are right together, but there is no back pressure pushing on it. So if you get a short and long piece, it does not start turning on you. We’re real happy with how that turned out.”
Rather than having to watch over the piece flow, the equipment operator can now focus on more of the upstream, making sure presentation is correct.
The end goal for the project—and it looks to be headed firmly in that direction— is to increase throughput by an additional three per cent above recovery gains. They are expecting a six to seven per cent increase in recovery, and the mill so far is dead-on in delivering on those forecasts.
“We also expected a little better grade recoveries, as well, and we’re seeing that,” says Dunwell. Synergy is at work regarding that. The planer operation, which is turning in some very impressive production numbers, is also generating some good numbers on grade yield.
Besides the huge team effort required by mill employees and the upgrade project staff, suppliers played an important and often flexible role, as the project proceeded. Tembec was the prime contactor on the project, but Anthony-Seaman Ltd was the prime engineer. Site project coordination was handled by Paradigm Construction of nearby Fernie. Local fabricating shop Fab-Rite Services provided civil, structural, and mechanical installation services. K2 Electric of Prince George, BC, handled the electrical installation and Linden Fabricating provided a log ladder to feed the new canter line. Arrow Speed Controls supplied the variable speed drives and large motor soft starters.
Project delivered some heartburn on the hydraulics
D oing a mill upgrade at Tembec’s Elko sawmill without a shutdown was certainly a challenge. To help keep the project—and the mill—moving smoothly, there were regular meetings between mill staff and the project staff. “The bottom line was communication, communication and more communication,” says Jon Pritchard, manager of wood products engineering for Tembec. “At every meeting, we reviewed what was going to be done, but it was still difficult for the mill people.”
As with any mill upgrade project, there were the inevitable unforeseen problems. “A drawing on a table showing where the equipment is going to be is one thing, and putting in a simple transfer deck can seem very straightforward— until you get down to the mill and see that you are going to pass through some big trays full of heavy cables that weren’t on the drawing.”
Overall, the hydraulics on the canter system caused—as Pritchard puts it— the “most heartburn.” It went from the original proposed 150 horsepower to 300 horsepower and pressure to 2,500 psi from the usual mill standard of 1,800 psi. “There were a lot of hard lessons learned in the heat of battle trying to get the system together. None of the usual SAE or JIC fittings are rated for the pressures when you get into the larger sizes. We were flying special fittings and hose in from all over North America.”
Things such as the hydraulics challenge threatened to become show stoppers in terms of bringing things to a halt. “But they were all resolved. And in the end, all the challenges are worthwhile when you see the equipment working well,” says Pritchard.
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