The borough will cover more than $85,000 in unexpected costs after construction was stopped at the Alder Top Village (Keishangita.’aan) subdivision when a shell midden was found on the site in August.

The delay and added costs have not changed the scheduled Dec. 1 closing date for bids on the 20 residential lots or plans for winning bidders to take ownership of the lots.

The borough assembly on Nov. 12 approved a payment of $85,783 to Rock N Road Construction of Petersburg to cover the contractor’s expenses during the three-week shutdown. Several pieces of heavy equipment stayed on the site and carried daily rental fees of $500 to $1,250, which continued to add up while work was on hold.

An archaeologist was also kept on standby during the shutdown, with that expense, additional permitting, pulling together a plan to protect the artifacts and lodging added up to $30,783, separate from the equipment rentals.

Borough Manager Vason Villarma said the borough will absorb the costs and can do so without harming its finances because money was available in the project budget.

The borough expects the total bill for developing the residential subdivision to come in at more than $4.1 million, of which it will recover a portion from sale of the lots.

The online auction closes Dec. 1. As of Nov. 14, bids had been submitted for three-quarters of the parcels, with several receiving multiple bids. The starting prices range from $49,800 to $75,400.

Villarma said the discovery of a shell midden at Alder Top has pushed the borough to look at how it should respond if similar discoveries happen on future construction projects.

A midden is a buried mound of discarded shells, likely from past users of the property.

A study found that the midden is historically significant but not culturally significant, so the subdivision work was allowed to continue.

Villarma said the borough is currently waiting for a mitigation plan from True North Excavation. The plan will give clear directions on how to protect and work around the shell midden without permanently removing or destroying it.

Construction stopped in August after workers uncovered what was initially described as “inadvertent cultural discoveries.” The borough consulted with state and federal agencies and the Wrangell Cooperative Association. The shutdown lasted from Aug. 19 through Sept. 4.

During that time, the U.S. Army Corps of Engineers and the State Historical Preservation Office agreed that a foot bridge, concrete foundation and piping found at the work site were not historically significant. They also agreed that the shell midden needed more review and either had to be avoided or handled through mitigation.

The contractor restarted work on Sept. 8.

The contract with Rock N Road Construction includes leveling the land, putting in streets and buried utilities to prepare the lots for winning bidders to construct homes.

“It is expected that the contractor … will have to return to complete the sewer line installation in the shell midden area once the work identified through development and consultation of the treatment plan is complete,” according to the staff report to the assembly. “There will be additional costs associated with the remobilization of the contractor to complete the sewer line work.”