Charcoal Kilns

Photo of kilns at Gilmore by Larry Prescott

Twelve charcoal kilns were built on the west side of the valley to serve the mines across the valley at Nicholia. Most of the kilns were dismantled when mining ceased, but four remain. They are now owned by the U.S. Forest Service, which has stabilized them and installed interpretive displays.

The kilns are located off Highway 28 in Lemhi County, 10 miles south of Gilmore Summit.

The kilns were built in 1883 by Warren King of Butte, Montana, and the materials were made on-site. These kilns fueled the Viola smelter which produced high grade ore between 1882 and 1885. It was the largest lead producer in Idaho, outside the Coeur d'Alene valley. The smelter could process 100 tons of ore a day, but required vast amounts of charcoal. Charcoal was produced here from 1883 to 1889. At that time about 300 immigrants lived on the flat and cut Douglas fir in the nearby canyons. The logs were hauled to the kilns and bucked into four-foot lengths. The kilns were loaded through the lower door; when the lower course was completed, an opening was made in the dome and the loading proceeded. Once the kiln was full, tinder in the base was ignited, the doors were sealed, and the draft vents in the base were carefully regulated. The slow burning reduced the wood to charcoal.

The kilnmaster watched the color of the smoke to tell when the wood had been reduced to charcoal. Volatile gasses sometimes blew the top off the kiln. There were sixteen kilns here at one time, but the bricks were salvaged by settlers. It is estimated the ovens burned 150,000 cords of wood in seven years. When the Viola closed, forty acres of cordwood were stacked on the bench behind the kilns, and the owner could not even give it away. Lead poisoning was a serious problem at the smelter. It killed men who worked in the plant as well as the area's pets and livestock.

The kilns are twenty feet high and twenty feet in diameter; their capacity was approximately thirty-five cords. As the moisture, noncombustible gases and tars were distilled, the wood was reduced to carbon with one-half its former volume and one-quarter of its weight. A cord of wood yielded about 500 pounds of charcoal. It took a week to load, fire, and unload a kiln. Wagons then carried the "coal" to the smelter across the valley.