Hi, Rusty!
Never-the -less, I did just have quick look for "word- mining".......
But no, you are quite right, you may lay claim to the word........it does not appear to be in the dictionary!
You have coined a new word!
I like it!
Chambers gives a "rattle", used as a noun, as a vivacious prattler.......
But stick "brain", "head", or "pate " on to "rattle", and one becomes a "shallow, voluble, volatile person"!
I rather think Jane Austen may have meant her heroines to be regarded in a kinder sense?
I have yet to watch tonight's "Eggheads"......