Coal mining is all about location. The size of a mine and the area of its seams will determine how much a miner yields, and how exhausted he will be by day’s end, and this means everything when he is paid by the ton. This, more or less, was the grievance of a band of Wyoming miners in September 1885, as they brutalized three Chinese laborers working in a favored pit, killing one of them. Over the following several hours, 79 houses were destroyed and 28 people were killed.

Resentment went far deeper, and had simmered for far longer, in the years leading up to the Rock Springs massacre. Through the late 19th century, Chinese immigrants had gained increasing employment in the manual industries of the American West. They became especially valuable to companies during labor shortages, which grew in frequency as white workers became more confident striking and organizing against extra work. Crucially, Chinese workers could be paid less. When working side by side, white workers would fume with the suspicion that the unassimilated foreigners around them were depressing their wages. This was the case in Rock Springs, Wyoming.

The nation’s growing anti-Chinese sentiment officially showed its hand by way of the Chinese Exclusion Act in 1882. Prohibiting the further entry of Chinese laborers, it became the first law in the nation’s history to target immigrants by race. In Rock Springs, an organization called the Knights of Labor formed a chapter where Union Pacific’s white miners, now one-third of their site’s workforce, could assemble and pronounce their complaints. Many white miners were in favor of expelling the Chinese.

The fight in the mines broke out around 7 a.m. on September 2, 1885, when about ten white miners approached the Chinese workers in coal pit № 6, claiming they had no right to work in the high-yield mine. A brawl erupted between the men and three Chinese miners. One Chinese worker took the fatal blow of a pickaxe to the skull. The site’s foreman broke up the fight, and the white men took off, setting in motion a conflagration that would last into that night.

The gang of men did not retire after the fight; instead they armed themselves with guns, knives, clubs, and hatchets. At 10 o’clock, miners gathered in the Knights of Labor hall, where anger echoed and reverberated. After the meeting they filed into shops and saloons, where barmen soon began to sense the growing hostility and aggression, and at the urging of a Union Pacific official, closed their establishments around 2 p.m. On the move, the mob swelled to some 100 to 150 miners and townspeople, some of them women, armed and looking for what they considered retaliation.

Rock Springs was divided by race, and laborers dwelled in their separate quarters, in this case “Whitemen’s Town” and “Chinatown.” The mob split up into groups, some marching toward Chinatown, others blocking railroad bridges or moving toward the mines. A small group reached Chinatown first, and informed the inhabitants they had an hour to pack up and leave. After less than half that time, the mob fired its first shots, and in the pump station a worker named Lor Sun Kit was the second person in Rock Springs that day to die.

At coal pit № 3, a splinter of the mob began firing on and killing Chinese workers. In Chinatown, they continued the violence, and looted and set fire to buildings, destroying some 79 shacks and homes. Some were too ill to move, or took refuge in their cellars, only to be burned alive. As the 350 Chinese people in Rock Springs began to scatter for safety, mobs harassed them, demanding their jewelry and valuables, sometimes pummeling victims with the butts of their rifles, even when they complied.

In all, 28 people were killed, some of whom were decapitated, scalped, and castrated. Corpses were taken and hoisted into the flames of burning buildings. Owing to the destruction of evidence and the scale of the flight, some estimate the death toll to be closer to 40 or 50.

The mob told the Union Pacific managers responsible for hiring the Chinese laborers to take a train and leave. The fleeing Chinese made their way across the hills to safety, and many went toward the nearby town of Green River, following the railroad tracks as a guide. The next day, Territorial Governor Francis E. Warren came from Cheyenne and ran a slow train along the landscape, providing food and blankets to the fleeing townspeople.

They were taken to Evanston, a town 100 miles away, which was also a mining hub where anti-Chinese sentiment simmered, and could erupt in violence if its white miners were to be emboldened by the slaughter in Rock Springs. In a wise strategic move, Warren sent telegrams to the president requesting federal protection for the hundreds of new refugees. They also brought in a Gatling gun from a nearby town.

In the aftermath, authorities arrested 22 people and charged them with robbery, rioting, arson, and murder. But no witness could be brought forth to attest to the crimes of another member of the mob, and all were acquitted a month later. After no one was convicted, they were greeted by an ovation after release from the threat of law. President Grover Cleveland compensated the Chinese government for $147,748 worth of damages, what they determined was the cost of the looted and burned property. The order came on the heels of a wary diplomatic exchange, which included the secretary of state’s censure to Chinese immigrants for being particularly disinclined to assimilate.

On the PR front, western newspapers were often sympathetic to the white miners, sometimes revising history to make their allegiance more sound. An editor of an Oregon paper claimed it was really the Chinese, who, after a scuffle in the mines, came armed with rifles and knives. In his version, they died not from any violence but from panic at the sight of the miners’ mob which formed in response, leading the Chinese to run themselves into the creek where they drowned or were fatally trapped in the mud. Another paper, this time from Kansas, insisted that it was actually the Chinese “who set fire to their own houses to prevent the white men from robbing them.”

For its part, though, The New York Times ran editorials denouncing the law’s failure, declaring “If there are ten righteous men in Rock Springs they have given no evidence of their existence.”

As for the Chinese immigrants: after the dust somewhat settled in the following weeks, officials put them on a train bound for the more tolerant airs of San Francisco. But when the train stopped, they saw that they had been fooled. They had been shipped right back to Rock Springs, against their will. It took a few days, but Union Pacific got their restored labor force to cooperate. Coal still needed mining.