The slash pile fire at the Aspen Wall Wood mill south of Dolores has subsided significantly but continues to smolder nearly three months after it began.
Smoke from the fire is way down, and is barely visible most days, said mill owner David Sitton. Flames are no longer seen.
“It is still smoldering, and thankfully there is much less smoke,” Sitton said Monday. “We continue to monitor it closely.”
The fire erupted in a decades-old slash pile adjacent to the mill in Lost Canyon on Dec. 11. Local fire agencies battled a raging 10-acre blaze in high winds and frigid cold, and contained it by Dec. 13. The suspected cause was spontaneous combustion caused by heat generated deep within the wood waste pile.
On Feb. 11, a thermal imagery flyover of the fire site was conducted by the Colorado Division of Fire Prevention and Control.
The imagery showed that significant hot spots still exist deep within a 1-acre area of the remaining slash pile, said Dolores Fire Department Chief Mike Zion.
He said the fire remains contained, and the current risk of it spreading are low.
There is a concern however of increased risks when spring winds pick up and conditions become drier.
“We are checking on it regularly,” Zion said. “The best approach is to let it burn itself completely out while helping it along by mixing the pile.”
He estimates total burnout could take up to several more months. An additional thermal imagery flyover is expected when the weather dries out to assess the situation, Zion said.
“The thermal imagery showed more heat than we expected, and its coming from the deepest part of the pile,” Sitton said.
Where possible to do so safely, equipment is used to stir up the slash pile and allow oxygen in to speed up the burning.
Putting men and machinery too close the unstable burn area is avoided because of the potential for collapse.
Dousing the pile with water was considered, but fire officials said the water would not penetrate enough to put the deeply buried fire out, and could actually delay it from going out on its own.
The ash pile leftover from the fire is not considered a threat to the environment, Zion said. The burn area is quite a distance to Lost Canyon Creek, and it is not near any side streams. The slash pile was made up of aspen, which when burns does not create a lot of ash, he said.
Sitton said as a precaution, when fencing is repaired on the property line below the burn area, a dozer line or berm may be formed to prevent any potential ash runoff.
When the fire was fought, a massive effort went into protecting the mill, machinery and rows of drying lumber and wallwood paneling product.
The mill was spared any damage, and operations have continued.
“We feel very fortunate we did not suffer any damages. We had rows of drying lumber very close by. It could have been a lot worse,” Sitton said.
Smoke was heavy for weeks after the fire was contained, impacting neighbors and mill workers. Mill work had to be stopped several times because of the thick smoke, Sitton said.
The massive piles of wood that burned were scraps from the milling process. They are sold as firewood to regional residents who come out in droves every summer and fall to stock up for winter.
For decades, the wood scraps and sawdust were pushed over the side of the canyon, but that practice has not been done for many years, Sitton said. The firewood piles are stored in an area for safe public access.
“We work hard to find a market for the waste material to prevent it from building up onsite,” he said. “The firewood pile is growing again.”
In addition to the scraps sold as firewood, the sawdust is sold to horse racing tracks. In the future, the sawdust could be made into pellets for wood stoves.
Because of the pandemic, horse racing tracks closed, and the demand for sawdust went down, which has increased stockpiles at the mill, Sitton said.