Labor unions grew in response to these working conditions, and strikes were common as miners sought fairer wages and safer workplaces.

In 1890, the United Mine Workers of America (UMWA) submitted demands to the coke operators that included an eight-hour workday, wage increases, restrictions on house rent, and the right to union-only employment.

By early 1891, when production resumed, miners found that they were to be paid based on a sliding wage scale tied to coke prices, a change that many felt was unjust.

Tensions rose as workers and their families were evicted from company-owned housing, and Frick, known for his tough stance against unions, resisted their demands.

[5] In March 1891, violence erupted as striking miners, some facing eviction and economic hardship, began targeting company facilities and replacement workers.