If the IT guy of said library knows his job you won't be able to mine anyways, because he'll have blocked any ports except for HTTP, HTTPS and maybe the most common ports for Mail.

My advise: Just forget mining if you want to do it to "earn" money. Either safe up some Dollars and then just buy Bitcoins directly and do some trading (buy low, sell high) or do stuff that get's paid in Bitcoin, like a Signature Campaign in this forum.