Converting from 3/4" video to digital.
Assuming DVD quality would be enough, you may consider archiving 720p mpeg-4 files with a bitrate of 2 Mbits, which would equate roughly to 1 hour = 1 GB data.

That would mean 27,000 hours = 27,000 GB = 27 Terabytes.
So you need to consider a 50 TB storage system (including redundancy and overhead) and a tape backup system as well (LTO-6 has an uncompressed capacity of 2.4 TB per tape, so that would be relatively easy and cheap, the entire archive would fit into 13-14 tapes).

Higher quality requirements would increase the bitrate, hence the GB/hour ratio, and all values should be adjusted accordingly.

The tough part is the actual acquisition... analog video tapes have to be read at normal speed so 27,000 tapes, assuming 1 hour each, means 27,000 hours = 675 weeks = almost 10 YEARS... !!! To hope finishing this in a reasonable time (say 2 years), your company would need to set up at least 5 acquisition stations each with its own tape unit and computer (and operator). The operators, while saving, should monitor that there are not problems with the cassette and fill the metadata into the DAM system.

DAM systems, there are many, also open source, the choice depends on the use that will be made of the resulting digital video archive.