KETCHIKAN (AP) -- After taking a big bite out of a mound of sand, the construction crane's bucket slowly swings into place.
Behind the controls, Jerry Heisler of South Coast Inc. lowers the bucket directly above the desired drop spot and releases the sand where it is needed.
The bucket moves back near the sand pile, opens its jaws and the whole event is repeated over and over again, just as it has for the past few weeks.
A typical Ketchikan construction project involving heavy equipment? No.
This operation takes place on water, and doesn't involve adding to Ketchikan's infrastructure.
For the past few months, the ocean floor of Ward Cove has been getting a face-lift. As part of the environmental clean up of the former Ketchikan Pulp Mill site, workers have been pulling up sunken logs, dredging the cove's seabed and covering some areas with imported sand.
In the mid-1990s, the Environmental Protection Agency determined that about 80 acres of the almost 275-acre cove contained contaminants from the former mill, said John Lally, project manager for the operation's main contractor, Foster Wheeler Environmental Corp.
''The primary form of contamination is just the biodegradation of the organic components from the logging operations,'' Lally said. ''You bring in all those logs and the fallout from those is what affects the chemical makeup of the bottom and can impact the organisms. However, there is no sediment that is affected that is toxic to humans.''
Ward Cove was the home of Louisiana Pacific's Ketchikan pulp mill for almost 50 years before it closed in 1997. In that time, log rafts moved in and out of the cove, leaving behind debris that eventually sunk.
''So that is why the cleanup is happening,'' Lally said. ''It's basically to remediate those bottom sediments that have been identified as being a little out of whack.''
Of the 80 acres possibly affected at the cove, about 30 are being altered, said Lally. About 12,000 cubic yards of material was dredged. More than 700 tons of logs were pulled from the cove's sea floor. Those logs were placed in a stockpiling area and chipped.
''From there we moved into the bulk of the project, which is capping the bottom sediment,'' he said. ''Instead of removing material from the bottom, we are actually placing clean, imported sand onto the native sediments. By doing that we are just kind of amending it, in order to reduce the potential toxicity of the sediments, and that's really the goal.''
As for 50 other affected acres that are not part of the project, they will be left to natural recovery because the toxicity is not that great.
''We really are just addressing the areas where we can get in there and remediate by placement of sand or dredging,'' Lally said.
About 41,000 tons of medium-density sand has been barged up to the cove from Victoria, British Columbia, Lally said. About 26 acres are to be covered with the sand.
''We didn't want to use a real heavy sand that would penetrate the soft organic bottom, and do us no good, because it would sink,'' he said.
The capping is being done by J.E. McAmis Inc. of Chico, Calif., along with South Coast workers, using two barges side by side. One barge holds the sand and the other the crane. The crane's bucket, configured to hold 5.5 cubic yards, drops sand into the cove while swinging just above the waterline.
A differential global positioning system coupled with the bucket configuration allows the crane's operator to know where the bucket is at all times and how much sand has been dropped in each area.
''What that does is provide uniform coverage, so we don't have mounds out there,'' Lally said. ''Instead we have as uniform a bottom as possible.''
Is it working? Lally says it is. Foster Wheeler is using the Ketchikan-based Invader 1 vessel of Alaska Commercial Divers Inc., along with divers, to sample the cove's seabed. A 10-inch sample of the cove's floor is brought to the surface and studied to see if the sand is remaining atop bottom sediments.
''So far it's been going great,'' Lally said. ''It's exceeded everybody's expectations. So right now we are able to stick to our plan of providing a 6-inch cap of this clean, imported material.''
The project, which will cost $3 million to $4 million, is scheduled to end in early March when salmon begin migrating through the cove and into Ward Creek, Lally said. Louisiana Pacific is picking up the bill.
(Distributed by The Associated Press)
© 2018. All Rights Reserved. | Contact Us