Are used :  to replace possessive adjectives + nouns.

A)     In place of nouns functioning as subjects or objects.

Ex:  Since your video isn’t working, let’s take mine.

B)      After “of’ when it means “one of my”.

Ex:  A script of mine was chosen for the movie.

C)     After the verb “BE” to indicate possession.

Ex:  This ticket is yours, and that one is hers.