With an E – A person who digs a mine.
With an O – Small in size, significance, etc. A person under the legal age of responsibility. A musical term relating to scales with certain intervals lowered by half steps. Also, a secondary, subordinate educational degree – but that implies the "lesser significance" definition, doesn't it? So I didn't draw anything for that.
(Of course, I suppose the musical "minor" implies that definition as well, with the lowered notes. But I did decide to include that in the picture. Well, what can I say? I'm an illustrator, not a linguist. And definitely not a perfectionist.) :)