July 6
Two strikers and a bystander are killed, 30 seriously wounded by police in Duluth, Minn. The workers, mostly immigrants building the city’s streets and sewers, struck after contractors reneged on a promise to pay $1.75 a day - 1889
And this:

July 6, 1889 - Striking Duluth laborers were shot down by the police. In the summer of 1889, construction crews - many of them immigrants - building Duluth's streets and sewers went on strike when contractors reneged on an agreement reached the year before to pay $1.75 a day. When Mayor John Sutphin ordered police to keep strikers away from working men, fighting broke out between strikers and police, resulting in an hour-long gun fight on the corner of 20th Avenue West and Michigan Street that left two strikers and one bystander dead and an estimated 30 strikers seriously wounded. The police eventually suppressed the strike through violence, but the immigrant laborers continued to organize politically and went on to win the 1890 mayoral election.
Two barges, loaded with Pinkerton thugs hired by the Carnegie Steel Co., landed on the south bank of the Monongahela River in Homestead, Penn. seeking to occupy Carnegie Steel Works and put down a strike by members of the Amalgamated Association of Iron & Steel Workers - 1892
And this: July 6, 1892 - Striking workers battled Pinkertons -- hired detectives who were the predecessors to today's unionbusters -- at the Carnegie Steel Works in Homestead, Pennsylvania. The struggle at Homestead helped give rise to industrial unionism in the United States.

Rail union leader Eugene V. Debs is arrested during the Pullman strike, described by the New York Times as "a struggle between the greatest and most important labor organization and the entire railroad capital" that involved some 250,000 workers in 27 states at its peak - 1894
Transit workers in New York begin what is to be an unsuccessful 3-week strike against the then-privately owned IRT subway. Most transit workers labored seven days a week, up to 11.5 hours a day - 1926
Labor history found here:
http://www.unionist.com/today-in-labor-history & here:
http://www.workdayminnesota.org/index.php?history_9_07_06_2011