Up from the ashes
By Andrew Macklin
Rebuilding the Lakeland Mills sawmill following the tragedy of April 2012 was clearly not an easy decision for Sinclar Forest Products Ltd. president Greg Stewart.
The explosion at the mill left two workers dead and several others seriously injured. The explosion leveled the sawmill, leaving nothing but a piece of charred land where the mill once stood.
It took nearly a year of consideration before the formal decision was made in March of 2013 that the mill would be rebuilt. The Stewart and Andersen families had a long history in the sawmill industry in Prince George, and there was a strong business case for constructing a new mill.
But it clearly wasn’t as simple as just building a new mill. Stewart and his team realized they would have to take a new approach to the design, engineering and construction of the mill.
Stewart put together a team of mill staff, industry stakeholders and regulatory authorities to design a mill that would set a new standard for safety in the Canadian sawmill industry. The team then met several times to brainstorm ideas for how to create the safest possible work environment, without compromising mill efficiency.
“The design was the result of a collaborative effort by a team of Sinclar and Lakeland staff with the help of experienced sawmill vendors and engineers,” operations manager Bruce McLean said. “The safety standard was to meet new expected standards in sawmill safety, including dust management and guarding.”
To meet heightened safety standards with the new design, Sinclar consulted with WorkSafeBC, the B.C. Safety Authority, City of Prince George and the Prince George Fire Department, both during the design process, and prior to opening the mill. They were able to help contribute ideas on what features and equipment to implement to improve the safety of the mill as well.
Before the mill itself could be built, there was one additional safety measure that needed to be addressed. Shortly after the fire in 2012, mill officials became aware of a potential methane buildup in the ground beneath the mill.
“Methane mitigation is a big part of the project,” McLean said. “The site is an old fluvial area where the Nechako River meets the Fraser River with some old landfill areas, old petroleum from adjacent industrial areas, and organic layers buried. When we became aware of the possibility of methane shortly after the tragedy in 2012, we set up test wells throughout the site that confirmed its presence.”
Sinclar recruited HDR Engineering, which designed an extraction system for the sawmill and all other buildings on-site. System monitors can be found throughout the new mill, and are tied in to the emergency alarm system.
The most glaring difference between the former Lakeland Mills sawmill and the current mill is the switch from a pair of sawlines to a single USNR line. Previous production capacity for the mill was 225 million board feet on three shifts, while the new mill will reach a capacity of 200 million board feet on two shifts with the single line.
The entire system is currently built for cut-to-length eight-foot logs fed to the line by a Cat material handler. The Linden Fabricating two-stem step feeder feeds the logs, which are then fed to a pair of 22” A8 tandem air seal debarkers.
“The debarkers were identified as Class II, Div II under the NFPA 499 standard and they were certified in the Nicholson shop by Intertek,” McLean said. “The upgrades were with the electrical components. In addition, a dust collection system designed to minimize dust in and adjacent to the machine.”
Officials from Lakeland Mills approached Nicholson to discuss the need for the heightened safety standard, recognizing the debarkers would be operating in a potentially dusty environment. Nicholson obliged, bringing in a third-party contractor to perform the certification work for the electrical components.
The installation of the A8 debarkers was the first in Canada for Nicholson, which had previously only sold them to customers in the U.S. It also marked the first time in Canada that Nicholson was installing a system with hydraulic roll control for the feed roll system rather than the pneumatic roll system. The option has been available from Nicholson for approximately five years, but was typically sold to European customers looking for ways to save on power costs.
Sinclar has purchased a Log Pro log merchandizer that will be added to the line at a later time, allowing the mill to accept nine and 10 feet log lengths in the future.
Before reaching the main sawline, the logs are scanned by a Metal Detectors Inc. (MDI) system. The logs then enter the main building through the conveyor to the USNR primary breakdown line.
The new sawline is a USNR straight four-sided canting system, featuring two Quad Arbor Saw Boxes and a vertical double-arbor gang with profiling. The line is built to provide the operator with a high-speed, high production stud mill.
The mill required a line that would have three points of contact with the wood at all points throughout the sawmill to provide better control, reducing the risk of the saws losing control of the logs or the cant. So USNR modified the cutting tools section of the sawline, making the line shorter to accommodate more press rolls and feed rolls.
There were a series of other modifications necessary to meet the demands of the new Lakeland Mills, according to Petri Saastamo, mechanical engineering group lead at USNR: “USNR modified the QASB machines to address the needs of the mill, creating a simpler design with a lot less moving mass than standard,” he said. “The saws now move on the arbors like an edger so instead of moving whole side carriages, we just move the saws and guides. And there is no top motor, which reduces the amount of moving mass and makes it faster.
“The sideboard separators are semi-enclosed to contain sawdust. Boards drop to a belt, then fall to a slat bed chain that provides a soft landing. There is a gap in the conveyors that allows sawdust to fall through while the boards pass over it. This design is contained and prevents sawdust accumulation in this area from spreading out onto the floor and into the air.
“We did a lot of work on sawdust and chip containment at the canters and quad arbor sawbox outfeed. We made better hoods over parts of it that were connected with a dust collection system. We also extended the outfeed of the sawboxes, where sideboards fall off. We put belts on it, and shrouded in an area that the sawdust could be contained and removed.”
The larger sawmill residues are conveyed from the line to a Brunette SmartVIBE conveyor, which acts as a central collection point for feeding the disc chipper. That includes all larger residues processed at all saw points on the line, as well as the edging system.
Sinclar then introduced a new transverse edger system to the line. The system was designed by Ron McGehee of WaneShear, who built a system with accurate positioning that saws the wood while it is stabilized, to provide optimum recovery. The system is also built to maximize productivity, with a guaranteed processing rate of 55 bpm, but it expected to be capable of 60 bpm or higher.
Sinclar turned to Springer-Microtec for optimization of the transverse edger. Microtec had provided optimization equipment for the sorter stacker upgrade in the old mill, and the success of that installation resulted in Sinclar turning to the company for optimization equipment for the new mill.
“We installed two transverse scanners, one producing optimized edging solutions for the new transverse edger and the other controlling the green sorting line,” Springer-Microtec Inc. CEO Gero Springer said. “These optimization solutions allow Lakeland to realize the maximum productivity of their new investment.“
According to McLean, Springer’s Goldeneye 902 optimization system has “the unique ability to detect moisture content above fibre saturation point (with low level X-rays) as well as below fibre saturation point with standard capacitance sensors.”
After passing through the edging system, the boards and lumber are sent to the Mill Tech Industries sorter line. Like the previous mill, the new Lakeland Mills sawmill will focus on the production of premium grade 2x4 studs, as well as 2x3 and 2x6 studs, along with 1x3 and 1x4 board stock. The mill will also incorporate some metric sizes in addition to the standard lumber products.
The stacks are dried in three Wellons Canada kilns, which are the kilns from the original mill. One or two of the kilns are set to be replaced as Sinclar transfers equipment from the nearby Winton Global site to other company properties.
In addition to the rebuild of the sawmill, money was spent on upgrading parts of the planer mill. Lighting and electrical wiring and circuitry was updated in parts of the planer mill to improve energy efficiency. Planer meters throughout the planer mill, which were previously open, have all been closed to improve safety. Additional investment to help provide dust mitigation and guarding is forthcoming in the near future. There are also capital expenses planned to improve trimming, stacking and wrapping in the planer mill.
|Allied Blower provided a specially-designed system that both aggressively removes dust, but also provides return air to keep the mill warm, and pressure stabilized.
Additionally, there is room for potential future investment in the sawmill, which has been built with enough room for a second sawline - should market conditions remain strong - and the required fibre is accessible long-term. The sawmill is also built to accommodate a second bin sorter and edger as well.
Start up of the new mill began in December, with the planer mill online in late January. The new mill has 110 staff for two shifts, versus the 160 staff needed for the three shifts run at the old mill.
“We are fortunate to have nearly all employees return and the areas we needed to hire additional staff were for maintenance and production supervisors,” McLean said. “We are fortunate to be located in Prince George, which does make recruiting less challenging compared to more remote smaller communities.”
Now that the mill is operational, mill officials will soon learn if the construction of the new, safer and more efficient Lakeland Mills will allow residents of Prince George to forgive and forget the past, focusing instead on the future of forestry in the region.
Dusting off the past
Dust suppression is at the heart of the rebuild, which is why Sinclar introduced a cutting-edge dust removal system to the mill.
“Allied Blower provided a solution that would aggressively remove much of the wood dust from all the sources; saws, chipping heads, chippers, transfers, hog and barkers,” McLean said. “In addition, three of the six baghouses currently installed, have air returning to the plant to retain heat and keep the buildings from too great a negative pressure. These baghouses have Grecon spark detection and abort gates both before and after the baghouse.” He continued, “make up roof air fans throughout the building provide positive pressure with general airflow from top to bottom. The air permit limits required the use of baghouses as there is seven times the airflow than previously.”
Allied Blower was able to work within NFPA standards, BC Fire Code and Worksafe regulations in order to build a system that would address the demands of dust suppression put forward for the Lakeland Mills. According to Allied Blower, “The Lakeland baghouses are designed to remove 99.998 per cent of captured particulate and will meet WorksafeBC regulations for return air. The intent is to remove as much combustible dust as possible while still allowing large heavy particles to be taken away by the residual conveying system. To achieve this balance we implement industry best practices such as point source collection, push pull air mechanics, optimized hood design and conveying velocities, containment and integrated controls systems.”
Additional measures were implemented throughout the mill to contain, collect and suppress dust. Operator booths in the new mill were built from floor to ceiling, and process centres built with peaked roofs, so dust could not collect on hard-to-reach structures. Horizontal support beams were turned 45 degrees so dust could not accumulate on the flat surface. Flat beams were equipped with fabricated shedder plates. All of the factors combined provide for very few points anywhere in the mill where any significant amount of dust could collect.
Opticom provided a state-of-the-art camera system to track mill operations in the operator booth, and the main floor, including several points with fire extinguishers and additional safety gear. At the height of the mill, Murray Johnson Engineering provided a specially designed sprinkler system complemented by the Siemens Canada fire alarm system. Also, the roof trusses are gluelam; removing opportunities for dust to collect.
While an official number was not provided, it is estimated the dust suppression and safety modifications made throughout the mill added several million dollars to the cost of the rebuild.