I did something like this, minus with penumbra sounds.
Sometimes when you would be mining, you'd hear a loud yell, followed by a distant cave-in. Played around a lot with making sounds seem distant.
I actually have a sound file you can use, it's using the default stone walk sound,
You hear something walking,
in the distance,
suddenly it stops,
and you hear it's pace getting faster
drawing closer
it's coming from the left,
now the right,
it must be so close it's in front of you--
then a loud sigh, followed by silence.
MINECRAFT - SHIT YOUR PANTS EDITION.