Demolition crews working to clear the way for construction of the downtown arena have unearthed some costly bits of old junk.

Under a 1950s dock at 310 and 320 S. Commerce, workers found the foundation of a 1920s building. It had been filled with sand and capped with concrete half a century ago, said Assistant County Manager Ron Holt, who is directing the arena project.

Also, a filling station's two storage tanks, not used since the mid-1960s, were under a parking slab at 622 E. Waterman.

Bradburn Wrecking is asking for an additional $32,528 over the original contract with Sedgwick County, KS to cover the cost of removal of sand, old foundations, debris and the underground storage tanks.

The request was approved last week by the county's Board of Bids and Contracts and is expected to be approved by the County Commission at its meeting this morning.

Bradburn bid $46,742.33 to demolish buildings at 310, 320, 326 and 330 S. Commerce and 600 and 622 E. Waterman, according to county purchasing documents.

Nearly $210,000 had been contracted for demolition for a total of 16 vacant buildings as part of the arena project. The requested changes equate to a 15.5 percent increase.

Although officials suspected there could be old tanks at the site of the old filling station, "the hole was a surprise," Holt said.

"I hope it's the one and only," he said.

There are four buildings in the area yet to be demolished.