Somewhat? It is the big issue of course.
These are dangerous, very bad contaminants we are talking about.
And there is no way any 'cooling' effect of a super volcano will ever be significant.
That is the stuff of fairy tales.
Let's suppose that whoever tries is successful at transferring heat from 10km down to the surface.
That heat will end up in the atmosphere.
Already on the hook for the whole AGW scam, and maybe even some sketchy data, this will promote an increase in atmospheric temperatures which would otherwise not occur, except after a long time of that heat being transferred through over 30,000 feet of crust.
(30K ft. is pushing it for depth. I'd love to have a piece of that wellsite work, 'cause that won't go so quickly after the first 15K.)