By 1910, Tercio, Colorado's coal mines employed around 1,000 men and supported 300 families; the mine closed in 1915, and its coke works followed in 1918

When one company is the employer, the landlord, the grocery store, and the reason a town exists at all, what happens once it decides to leave? That’s the question Tercio, a small coal camp in Las Animas County, leaves behind. The mine sat 32 miles west of Trinidad and, by 1910, it employed roughly 1,000 men, with about 300 families living in the company town, according to Colorado Fuel and Iron: Company Mines at USC Scalar. But the mine closed in 1915, and the coke works it fed shut down in 1918.

Built fast, built for one purpose

Development at Tercio began in November 1901. The Colorado Supply Company store opened the following month, in December 1901, and the mine produced its first coal in April 1902. By August 1902, the company had built 100 houses, with plans for 400 more, and that same year it put up 600 beehive coke ovens, per the Colorado Fuel and Iron: Company Mines overview. The record doesn’t say how many of those extra houses were actually finished, only that by 1910 the camp held around 300 families. Either way, this was a town assembled almost overnight for a single job.

The Colorado Fuel and Iron Company, or CF&I, built entire towns for its workers to live, and pay rent in, according to the Colorado Encyclopedia. Many of the camps sat in remote locations, so the company store was often the only place to buy food and supplies, which meant most of what miners earned flowed straight back to the company. Tercio did have a school, a YMCA clubhouse with a library, a barber shop and a doctor, but these ran through the same company system as the rent and the groceries, keeping schooling, recreation and healthcare inside CF&I’s reach rather than offering workers any real independence.

The price of the paycheck

CF&I was a massive company. The Denver Public Library notes that CF&I once produced 75% of the coal in Colorado and employed up to 10% of the workforce. This industry was mostly run by immigrant miners living in isolated company towns. There was a lot of risk involved in the work. In Tercio, 19 miners were killed in an explosion in 1904.

Colorado miners died at roughly double the national rate between 1884 and 1912. Against that backdrop, tensions in the southern coalfields finally boiled over: a 1913 strike drew in close to 90% of the state’s coal workers and led to the Ludlow Massacre, the deadliest labor dispute in Colorado’s history.

The decline of Tercio

By 1913, the coke ovens were already running at reduced capacity, and the mine itself closed in 1915. Coking at Tercio, however, continued for three more years: USC Scalar’s records indicate the ovens kept running on coal hauled in from the nearby Primero mine after Tercio’s own seam was exhausted, finally shutting down in 1918. The company store outlasted both, staying open until 1949. The broader industry followed a similar, slower arc, by the 1960s, Colorado’s statewide coal production (not Tercio’s specifically) had fallen to a fraction of its earlier scale, per the Colorado Encyclopedia. This isn’t a story of heroes and villains. It’s a record of how completely a community’s fate can be tied to a single employer, and how quickly that can come apart once the employer moves on.