The property history of Trementina Base is complex. The Federal Register shows that CST has owned two properties in the same area at different times. The one they originally built the underground vault on, between 1986 to 1992, was traded to the U.S. government on 24 August 1992:

Department of the Interior, Bureau of Land Management Number: G-910-G3-0006-4210-04; NMNM 83264

The United States issued an exchange conveyance document to the Church of Spiritual Technology, a California corporation, on August 24, 1992, for the surface estate in the following described land in San Miguel County, New Mexico, pursuant to section 206 of the Act of October 21, 1976 (43 U.S.C. 1716).

New Mexico Principal Meridian T. 15 N., R. 22 E. ...Containing 400.00 acres (1.6187 km2).

In exchange for the land described above, the Church of Spiritual Technology conveyed to the United States the surface estate in the following described land located in San Miguel County, New Mexico:

New Mexico Principal Meridian T. 17 N., R. 23 E. ...Containing 400.00 acres (1.6187 km2).

The values of the Federal public land and the non-Federal land in the exchange were appraised at $28,000.00. The public interest was served through the completion of this exchange.

This image shows the two parcels of land in New Mexico:
[link to en.wikipedia.org]

According to a June 1992 Claims Court ruling CST had purchased the original site in 1986 for $250,976, then had invested millions in building an underground vault on the property. But the Federal Register record says both properties were valued at only $28,000 at the time of the land swap in August 1992. However footage from KRQE TV shows the presence of a vault built into the mountainside between the runway and the CST logo