The site of the massacre was the Domingo Santa María School,[a] where thousands of miners from different nitrate mines in Chile's far north had been camping for a week after converging on Iquique, the regional capital, to appeal for government intervention to improve their living and working conditions.

An initial volley that felled the negotiators was followed by a hail of rifle and machine gun fire aimed at the multitude of strikers and their accompanying wives and children.

[citation needed] The mining of nitrate had become the mainstay of the nation's economy at the end of the 19th century, Chile being the exclusive producer worldwide.

[8] Life in the mining camps—a nitrate works was known locally as an oficina, "office", a term whose use extended to the adjoining settlement—was grueling and physically dangerous.

[6]: 163  The enterprises exercised a severe control over the life and working conditions inside the mines, which rendered the workers extremely vulnerable to arbitrary actions perpetrated by the owners.

They began to mobilize politically, repeatedly petitioning the national government in Santiago to get involved and bring about improvements in their dreadful living and working conditions.

A large contingent of strikers traveled to the provincial capital, the port city of Iquique, carrying the flags of Chile, Peru, Bolivia, and Argentina.

)[citation needed] *Neither the Supervisor nor any works employee shall dismiss workers or their leaders who have taken part in the present movement without advance notice of between two and three months, or alternatively an indemnity between 300 and 500 pesos.

Soon after the journeys to Iquique began, this great conglomeration of workers met in Manuel Montt plaza and at the Santa María School, asking the government to mediate between them and the bosses of the foreign (English) nitrate firms to resolve their demands.

[citation needed] The acting intendant of Tarapacá Province, Julio Guzmán García, mediated negotiations with representatives of the pampinos (plains dwellers) until the arrival at the port December 19 of the titular intendant, Carlos Eastman Quiroga, and General Roberto Silva Renard, chief of the First Military Zone of the Chilean Army, accompanied by Colonel Sinforoso Ledesma.

Their arrival was cheered by the workers because a nitrate miners' petition to the government nearly two years earlier, under the previous president, had received an encouraging response, although the demands had not been satisfied.

The ministry relayed orders to the strikers to leave the plaza and the school and gather at the horse racing track, where they were to board trains and return to work.

While the meeting with Intendant Eastman was taking place in the Buenaventura nitrate works, a group of workers and their families tried to leave the spot, but troops opened fire on them by the railroad tracks and kept shooting.

[citation needed] At 2:30 in the afternoon, Renard told the leaders of the workers' committee that if the strikers did not start heading back to work within one hour, the troops would open fire on them.

[citation needed] At the hour indicated by Renard, he ordered the soldiers to shoot the workers' leaders, who were on the school's roof, and they fell dead with the first volley.

It would not be until 1920 that minimum labor standards started to be enacted, such as mandating payment in legal tender and setting the maximum length of the working day.

Renard was seriously wounded in 1914 in an assassination attempt on the part of a Spanish anarchist, Antonio Ramón, whose brother, Manuel Vaca, had been one of the victims of the massacre.