U.S. National Archives (Record Group 104 [Denver], Sequence 42, Letters Received 1897-1903)
National Archives series description:
This series consists of miscellaneous letters received by officials pertaining to the construction of the U.S. Mint, Denver. This correspondence was addressed primarily to the Superintendent of Construction at the Mint. The letters were sent primarily by the Supervisory Architect of the Treasury Department, although there are also letters from the Secretary of the Treasury, congressmen, engineers, inspectors, individual companies, contractors, and builders. A large portion of the individual correspondence is from the general contractor responsible for the project.
The letters relate to the construction of the new Mint building that was authorized by Congress in 1895. The letters contain information on personnel, labor, equipment, supplies, proposals, contracts, building specifications, inspections, and the testing of various systems, such as plumbing and electrical. Also included are progress reports, final examination reports, and final construction reports. Several letters discuss delays and problems that apparently plagued the early construction.
National Archives catalog record is at: https://catalog.archives.gov/id/2618735. See also the National Archives & Records Administration numismatic finding aids at https://nnp.wustl.edu/library/archivedetail/538870.