U.S. National Archives (Record Group 104 [Denver], Sequence 51, Mint Additions)
Correspondence related to Mint additions in Denver, 1934-1937, scanned at the National Archives (NARA).
Record group 104 (U.S. Mint), entry 51 [Denver]. Denver NARA series identifier is 8KRA-104-84-051. There appears to be no corresponding entry in the NARA online catalog (https://catalog.archives.gov/advancedsearch) for this series. It is likely a continuation of entry 50, which is described as follows:
This series consists of correspondence of the Superintendent of the Mint relating to a major addition to the U.S. Mint, Denver. The series contains letters sent and received by the Superintendent of the Mint concerning the building addition and remodeling done at the Mint. Included are correspondence and radiograms concerning the acquisition of land adjacent to the Mint, letters of proposal, certificates of real estate appraisals, assessed valuations of the proposed lots, and requests and cost estimates of new coin presses and refinery equipment. National Archives (NARA) catalog record is at https://catalog.archives.gov/id/2630911.
See also the National Archives & Records Administration numismatic finding aids at https://nnp.wustl.edu/library/archivedetail/538870.