In September of 1913, the United Mine Workers of America (UMWA) went on strike against the John D. Rockefeller, Jr. owned Colorado Fuel and Iron Company (CF&I) and other coal companies. Amongst the striking workers demands was a call for an eight-hour work day, 10% increase in pay, and an abolishment of the use of scrip to pay workers. When the coal companies refused the demands, UMWA members organized a strike. The coal companies replaced the strikers with replacement workers or “scabs” as they were referred to by the strikers. The strikers often harassed the scabs and sometimes the harassment resulted in fights and deaths. This tumultuous situation caused CF&I management to hire “strike breakers” to guard the mines and protect the replacement workers. As fights and skirmishes continued to breakout, tensions between the mining corporations and workers boiled over. And the Colorado National Guard was called in to help break the strikes. On April 20, 1914 in a small tent colony know as Ludlow, twelve miles north of Trinidad, Colo., the striking mine workers and their families were resting after celebrating Easter the previous day. Several Colorado National Guardsmen showed up at the camp and demanded the release of a man they said was being held captive by the strikers. As negotiations began between the two sides, tensions arose and a fire fight soon broke out. The battle raged the entire day. After a fiery blaze engulfed the tent colony many of the strikers fled but four women and eleven children, who were hiding in a pit below a burning tent, were suffocated and burned by the raging fire. All told 19-25 people died; sources vary on the final toll, but the event soon became known as the “Ludlow Massacre.” Because of the National attention and public outcry after the event, the House Committee on Mines and Mining released a report in 1915 that was instrumental in creating child labor laws and the eight-hour work day. The Ludlow Massacre is seen as the culmination of the "deadliest [labor] strike in the history of the United States." to see more photos go here .