The Imperial Mining Company began life as the A.D. Monroe & Bilberg & Thennis Mining Company, founded in 1904 and named for its directors. The name change came in late 1906, although directorship remained constant. In 1908 Imperial Mining was working on the Tiger-Poorman vein, in its Timber Queen claim, east of Burke, Idaho. Ill-equipped for extensive efforts at the Timber Queen claim, the company contracted another ADM & B & T enterprise, the Imperial Development Syndicate, to develop it. As the work progressed, Imperial Mining bought up the Imperial Development Syndicate. The claim yielded ore that was 43 to 48 percent lead. This rich ore ran out in 1915, but work at the site continued. From 1924 to 1936 the company survived by levying assessments, which led to the eventual takeover of the Imperial Mining Company by directors of the Hercules Mining Company and the Day family conglomerate. Here is a Capital Stock Assessment Journal, opened to 1922.

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MG 254 Oversize 40, image taken by Special Collections staff