- Created: Tuesday, 01 September 2009 08:00
- Published: Tuesday, 01 September 2009 08:00
Keeping the world economy in perspective, Winnipeg, Manitoba, is surprisingly OK. There are several projects set to consume large amounts of concrete in the area including a human rights museum, which is being funded by more than $98 million generated by a private-sector campaign. About $193 million has been committed to build an inland port around Winnipeg's James Armstrong Richardson International Airport. There also are multimillion-dollar initiatives to rebuild local highways. Even the housing market isn't in a total slump, reports James Kaskiw, operations manager for Inland Aggregates.
ìHousing is still strong,î Kaskiw says. ìWe have some major infrastructure work on some highways that is going to keep us rocking and rolling.î He further describes the current season as abnormally busy for the Pine Ridge Aggregate operation.
This operation marks a $25 million investment for its parent company Lehigh Heidelberg Cement, which launched the greenfield operation to replace another that will soon be fully depleted. Pine Ridge has been permitted for 40 million tonnes of granular concrete aggregates. This new site is fully automated and incorporates a brand-new crushing and wash plant that's fed by a 16-cubic-yard Rohr GT-1000 clamshell dredge. Raw material is carried directly from the pond and through the processing plant without a single wheel loader, Kaskiw says.
Inland first broke ground in May 2007 and spent all of last summer commissioning the site. Kaskiw says permitting was not a difficult process. The area has a rich history dealing with aggregates and is just outside of city limits. However, it's highly competitive, Kaskiw says. There is Lafarge, which rivals Inland in size, but there also are several family owned operations in the vicinity to help keep the market honest.
This new site should keep Inland in the game for the next 30 years, having just cracked the surface. The overburden consisted mostly of small poplar trees. There's no market for these for either timber or burning, but they will provide a nice mulch for reclamation.
Once enough overburden was stripped off, Inland began preparation for the installation of the $4 million dredge. This was about two years ago, Kaskiw says. Using an excavator with a long extension, the company was able to dig out a 250- by 250-foot pond to a depth of 30-feet. This provided just enough space to float the pontoons and begin construction of the massive clamshell. It was built over the winter. Kaskiw says the ice offered additional stability for installation.
The Rohr gantry-style dredge is fixed to a four-point guy-wire system for navigation, using old buckets buried with material to serve as anchor points. However, it rarely moves, as it continuously scoops from the center of the lake bottom. Its 16-cubic-yard bucket can dig up 900 tonnes per hour at a depth of 60 feet, but it is capable of reaching 110 feet.
It's a mucky material with excessive clay, so material is washed thoroughly at the plant. A two-way rake grizzly also helps remove the larger chunks of clay. All oversize is crushed onboard by a jaw crusher. The vessel also includes an onboard fines-recovery system, 6- x 20-foot double-deck high-frequency dewatering screens to minimize the handling of washout fines, a vertical pump and cyclones. This equipment is kept under the scope of Rohr's bucket-monitoring and diagnostics system.
That material is delivered to shore by a 42-inch-wide floating conveyor. In the unfortunate event of a dredge breakdown, an auxiliary feeder is available to maintain a flow of incoming material to a prescreening plant that separates the sand from the gravel, which is stacked into separate stockpiles above a concrete surge tunnel. Several overhead gates feed the conveyor line to provide the plant with the perfect blend.
Perfection is a 50-50 ratio of sand to gravel, but unfortunately the deposit is about 85% sand. To bring balance to the material feed, Inland must pick up rock from other areas. The first source is the bank of the pond where they dig and screen rock. Another source is about a mile down the road, where a subcontractor maintains a separate dredging operation.
ìIt's the nature of the beast,î Kaskiw says. ìWe have to do it.î
The blended material goes straight to the top of the KPI-JCI processing plant via a conveyor line with an 18-degree incline. In hindsight, Kaskiw says a 12- to 15-degree incline would have been ideal because material is on the verge of rolling back. Also, the abrasive material is coming off at a high rate, 85 feet in the air. This creates a major wear point at the top feed chute. Since its installation, Inland has lined the chute with 2Ω-inch sheets of hard rubber, which should last one season, Kaskiw says.
This $20.8 million plant is fully automated and rated for 1,100 tonnes per hour, which will allow room for growth. It includes twin processing lines including 8- ◊ 20-foot primary screens, 4- ◊ 30-foot log washers, 8- ◊ 20-foot finish screens, 12- ◊ 48-foot classifying tanks and fines-recovery cyclones.
All material larger than 1 inch is scalped by the primary screen and is cycled back to the cone crusher, which has a 100-ton surge bin. The second screen has a º-inch mesh and diverts material to two sand classifying tanks. Everything else goes into the log washers to knock off excess organics. Material receives an additional rinsing at the finish screen. Sand is dried by two dewatering screens. One is for concrete sand and the other is for pool sand. A small amount of golf course sand is screened by a third.
With the exception of the golf-course sand, wheel loaders only come into play when the trucks are waiting to be loaded. There are seven loaders, all Caterpillar and mostly 980s. A few are equipped with bucket scales. But Kaskiw says most operators rely on experience, and there still are occasional overloads.
All incoming trucks are tagged with radio-frequency identification. The dispatchers read the trucks at the weigh-in scale, and notify the loaders to be ready. Once filled, drivers go straight to the loudout scale where they directly receive their ticket from an on-scale printer. Kaskiw says the scales all are unmanned.
If that's not impressive enough, two centralized dispatchers at Pine Ridge also are managing loadouts at two other operations. This is made possible through an impressive series of video cameras blanketing the operations that are monitored on screens the size of an average living-room television. These cameras help dispatchers guide drivers through loading and ticketing.
It's a busy job, Kaskiw says. ìNormally you wouldn't be able to get five minutes of their time. And there are only two of them, and they run it quite efficiently.î
This technology was inspired by Heidelberg's European standards. It is new to North America. Unfortunately, the equipment suppliers are overseas and working with a nine-hour time difference. Kaskiw says he might reconsider if he could do it all over again.
The Pine Ridge aggregate operation is most impressive for its energy savings, Kaskiw says. Everything is electric and powered by Manitoba's hydroelectric dams. Its proximity to Winnipeg also minimizes transportation's impact on the environment and the local community. Diesel consumption on site also is at a minimum, as conveyors are heavily relied upon.
From an economic standing, good location and energy efficiency keeps the costs competitive. So the end user, which is largely Winnipeg, will be getting the most out of its dollars. Hopefully, it will be enough to keep the recession at bay.