I can add some details, namely that the USofA began development on the SR-71 in 1957 | 1958 at which time the only ilmenite mine in Australia was a relatively low volume affair in Bunbury, Western Australia.

Ilmenite is named after the Ilmenski mountains in Russia where the mineral was first discovered in relatively free abundance, the other principle source for titanium is rutile sands .. typically volume access to rich old sand layers requires strip logging of large areas of old growth forest to then remove acres of overburden to then hoover up a band of sands.

Circa late 1950s if you wanted large volumes of high grade ore your choices were pretty much Russia and ..., err, Russia.

( That or subsidising mineral exploration at scale and developing other sources .. which did happen but over a longer timescale .. meanwhile the first flight of the SR-71 was in 1964 )

There's more on the mining apects at the Geoscience Australia page:

https://www.ga.gov.au/education/classroom-resources/minerals...