This is an archived article that was published on sltrib.com in 2017, and information in the article may be outdated. It is provided only for personal research purposes and may not be reprinted.

A 2,100-acre wildfire ignited and continued to burn Tuesday in Box Elder County but was not threatening structures, fire officials said.

A helicopter and 35 firefighters spent the day near Promontory, working to control the Long Ridge Fire, which was 20 percent contained at 7 p.m., according to U.S. Forest Service representatives at Uinta-Wasatch-Cache National Forest. People discovered the fire about 9 a.m. Tuesday, though the cause was unknown and under investigation Tuesday night.

The Highway 6 Fire, reported just before 2:40 p.m., burned 3 miles east of the windmills in Spanish Fork Canyon and consumed at least three acres, the Forest Service said.

Grass, brush and Pinyon pine fueled the fire, while 40 firefighters and a Utah County engine fought to contain it. Officials estimated that the blaze would be contained late Tuesday.

In eastern Utah, near Bonanza, the Mack Shaft Fire continued burning at 2,453 acres in its fifth day. It was 25 percent contained, according to the UtahFireInfo website.

The Choke Cherry and Snowfield fires were contained at 228 and 140 acres, respectively, in southern Utah, and the nearby Brian Head fire was 30 percent contained at 1,200 acres Tuesday night.

A field caught fire in Clinton about 1:15 p.m. Tuesday as someone was mowing it, said Clinton Fire Chief David Olsen. The machine threw sparks into dry grass, leading to a brush fire that enveloped seven acres.

The fire burned within 75 feet of structures, Olsen said, but it was contained within a couple of hours by firefighters from multiple agencies. No one was injured, and no structures were damaged.

Other small fires broke out in Box Elder and Utah counties, but they were contained by local firefighters within a few hours.

Twitter: @mnoblenews