The process of extracting and indexing the words in an audio file and then using that index to search the file for specific words or phrases.
"Come to think of it, the experience of reading Ambrose's book itself points to a needed technology. I listened to it on my MP3 player and have no printed copy. Suppose I wanted to double-check the kind of wood the railroad men replaced those cottonwood ties with. How can I search an audio stream to find the exact word I need?
The technology to do that it's called audio mining is going to make recorded speech as index-able as printed text."
Paul Gilster, "Tech money is drying up, but not ideas," The News and Observer, January 1, 2001
It's easy to think of other business applications in which audio indexing (Dragon calls it audio mining) could be useful, as in reviewing call center tapes for insurance companies, stock brokerages, banks, order desks and other places where verifying financial transactions is important and access is otherwise difficult.
Bill Machrone, "Audio mining: New way to dig for data," PC Week, March 1, 1999
This term it's also called audio indexing appears to have been coined by Dragon Systems, one of the companies involved in creating audio mining technology (see the earliest citation).