The United States Bureau of Mines was established by the Department of the Interior on July 1, 1910.
Notes on verification
Confirmed by multiple government and historical sources (NIOSH/CDC, Wikipedia, mining history archives) distinguishing the May 1910 authorization from the July 1, 1910 operational establishment date.
Sources
- 100 Years of Respiratory Protection History | NPPTL | NIOSH | CDC (archive.cdc.gov)
- https://www.usbr.gov/history/borhist.html (usbr.gov)
- https://www.osmre.gov/about/history (osmre.gov)