cf Cripple Creek strike of 1894, Colorado Labor Wars of 1903-1904
Colorado Coal Field War Project (University of Denver)
Colorado coal miners went on a massive, 14-month strike starting in September 1913 and eventually failing in December 1914. Many of the miners and their family members were killed by soldiers and mine guards.
In the 30 years leading up to the strike, at least 1700 workers died in Colorado coal mines. In 1913, when operators refused to meet demands of the United Mine Workers of America, 10,000 miners representing about 90% of the workforce went on strike. The workers mostly lived in company housing, from which they were promptly evicted, and they moved to UMWA-funded tent cities. Ludlow was the largest tent city, containing about 200 tents and 1200 people.
Mine operators brought in strikebreakers and the Baldwin-Felts Detective Agency and began harrassing and attacking the strikers. By October, operators had pressured Colorado Governor Ammons to call in the National Guard, which quickly abandoned the pretense of neutrality and operated as a brutal strikebreaking force. However, by April, the state could no longer afford to sustain the deployment, and withdrew all but two of the National Guard companies.
The two remaining militia companies were composed mostly of mine guards. On 20 April 1914, the militia fired machine guns indiscriminately into Ludlow and burned the tents, killing people trapped inside. At least 25 people died, including four women and ten children trapped in a pit dug under a burning tent. This event is now known as the Ludlow Massacre.
After the Ludlow Massacre, the strike escalated into all-out war. The so-called “10-Day War” was ended so early by reinforcements from the federal government, but the strike continued until December 1914, when the strikers were finally defeated.
Around 400 strikers were arrested en masse and most were charged with murder. None of the strikers were found guilty, but the trials lasted until 1920. 10 officers and 12 enlisted men of the Colorado National Guard were court-martialled for reasons related to the Ludlow Massacre, but all were exonerated.
The strike was a failure for the UMWA in an immediate sense, but it is seen today as a turning point in American labour history, turning American public opinion in favour of workers and motivating later reforms.