DELTA, Utah - Authorities planned to resume searching the rugged Utah desert today as part of a nearly two-year investigation into a missing mother after three days of digging in what had been described as a shallow grave turned up no remains.

Cadaver dogs led police to the site Wednesday just off a dirt road near the base of Topaz Mountain, a popular rock-hounding spot in remote central Utah. The area is more than 130 miles from the location where Susan Powell was last seen at her West Valley City home on Dec. 7, 2009.

"We hoped we would find the hard evidence that everybody wanted," West Valley City Lt. Bill Merritt said Saturday.

Instead, authorities found small charred chips of wood in the hole.

"They obviously have some type of human decomposition on them because that's what the dogs are hitting on," Merritt said.

The wood chips were being brought back to Salt Lake City for further examination.

Authorities have been searching the area since Monday. On Wednesday, they said they found human remains but later backtracked, clarifying that cadaver dogs had alerted them to the site but no remains had been found.

Police plan to continue with their search for remains in the area today.

The spot is about 30 miles south of where Powell's husband, Josh Powell, told police he took his two young children camping on the night his wife vanished. He told police he and their young sons - then 4 and 2 - left his wife at home about 12:30 a.m. The 4-year-old confirmed the trip to police.

Josh Powell is the only person of interest in the case, although he has never been arrested or charged. He has denied having anything to do with her disappearance and said he believes his wife ran off with another man.

Susan Powell was 28 when she was reported missing after she failed to show up for her stockbroker job.

Susan Powell's father, Chuck Cox, was escorted to the scene Friday for a look at the excavation effort.

He believes the area amid central Utah's sagebrush-dotted high desert and jagged mountains is a logical place to conduct the search because Josh Powell had camped at nearby Simpson Springs.

Cox, a former investigator for the Federal Aviation Administration, said he had long believed the search for his daughter would be a lengthy process.

"There's no real false hope, it's just another step in the investigation," Cox said. "Every day is hard for the family. Life goes on, and so you go on the best you can. It's something you have to live with."