Not minutes from 1/1/1970 as that puts you in the 4000's. Could be seconds though.
Overall this is a mystery and you need to find someone involved in creating the application so you can get a definition. Or you need to dig around the Oracle DB to find any conversion that might be done there or in the application.
Can you use the application that connects to the database to create a row with a known date and use that to decipher the format?