"It is a mystery," White said. "We don't know these people, where they came from or where they went."

Tanner and White compare old photos with newer ones, looking for damage or changes to the panels. They talk to archaeologists about what the drawings might mean.

Their efforts are all in the name of dust and how it's affecting air quality — and works of art.

Tanner and White consider it their full-time job to look out for the air and art in a canyon that can on some days register hundreds of vehicle trips. Most of it is industrial traffic these days through Nine Mile's side roads in Gate, Dry, Harmon, Cottonwood and Prickly Pear canyons.

The two men contend the industrial traffic is driving away tourists, who Tanner and White say don't want to deal with 80,000-pound trucks on a dirt and gravel road that sometimes barely has room for one vehicle.

Barrett's trucks use the canyon roads to access the Tavaputs Plateau, where workers have already tapped into natural-gas deposits. The company also has its own gas-compression site contained in two large metal buildings located a few hundred feet from the main canyon road. Barrett, which owns land in the canyon, has no plans to expand the compression site.

On Monday, several drivers of water trucks could be seen dipping hoses into the canyon's Minnie Maude Creek. Because Barrett owns land in the canyon, the company has water rights and is allowed to use the creek, as long as it keeps a log of who is filling up, how much and when, for state regulators to review.

Also in the canyon this week were several large trucks with road crews working for the company and Carbon County. A recent flood had washed out several sections of road. It's frustrating for supervisor Ray Hanson, who is forced to devote his crew to the canyon road, which this week took priority over hundreds of miles of other county roads outside the canyon.

Hanson stopped Monday for a few words on how the county has spent about $1 million over the past 15 years on a road that used to belong to the state. The recent flood damage has Hanson shaking his head, frustrated at another "bandage" approach.

"That's all we can do down here," Hanson said. "We just open it up so people can get through."

He'd like to see the road paved — which is estimated to cost more than $100 million — or reclaimed by the state.

Hanson praised Barrett's efforts to control dust. On Monday, a variety of dust-control measures appeared to be working in the company's project area in the canyon.

Even Tanner and White could see that there was minimal dust, although they remained suspicious of the dust suppressants' impacts on the environment — and on the art.