John Hays Hammond was hired to manage the mine, and a new concentrator, The Old South Mill, became operational in 1891, capable of 150 tons per day.
Hammond became president on 2 July 1891, followed by Nathaniel H. Harris on 15 June 1893, when company headquarters were located in San Francisco.
In 1900, the company opened a company-built Kellogg school building, contributed to the construction of local churches, and started a loan program so employees could own their homes.
[1]: 13–14, 35 On 11 July 1892, violence erupted during a strike at two nearby mines, the Gem and the Frisco in Burke-Canyon, resulting in the deaths of 3 union members, a Pinkerton detective, and a nonunion worker.
Protesting a 1 April 1892 wage cut, after a 1 Jan. 1892 lockout, the union men forced the closure of the Bunker Hill mine.
Only with the passing of the Idaho State Workman's Compensation law, was indemnity determined for each injury or death, rather than settled by company benevolence.
[8] The Bunker Hill company employed Pinkerton labor spies to identify union members, who were immediately fired.
[8] The Western Federation of Miners launched an organizing drive at the Bunker Hill Mining Company.
[6] On 29 April 1899, union miners hijacked a Northern Pacific train in Burke and drove it to Wardner, the site of a $250,000 mill of the Bunker Hill mine.
[11] In 1900, after the Western Federation of Miners had been crushed in Coeur d'Alene, the Bunker Hill & Sullivan Mine operated with a ten-hour shift, seven days a week.
[12] Years later Harry Orchard, who had assassinated former Idaho Governor Frank Steunenberg, claimed to have helped to light the dynamite charges at the Bunker Hill mill.
[13] However, two Coeur d'Alene residents testified that Orchard was with them in Mullan, Idaho playing poker when the mill was dynamited in Wardner.
In addition to the Star ore, Bunker Hill acquired zinc-lead-silver mines in the Pine Creek District, which they developed from an extension of the Kellogg tunnel.
During the Great Depression, Bunker Hill kept production at pre-depression levels to keep its workers employed at the same wages, even if it meant an operating loss for the company.
[1]: 88, 96–97, 99 During WWII, Bunker Hill added an antimony electrolytic plant, and because of the manpower shortage, employed about 200 women.
In 1942, the miners were finally able to organize, voting to join the International Union of Mine, Mill and Smelter Workers.
That led Gulf Resources & Chemical Corp. to purchase Bunker Hill stock in a hostile takeover bid.