No. It's different than your account un/pw. You should have workers listed somewhere on your account page (I've never used wemineltc.com, however). If there's nothing listed, you may have to create a worker, which should be somewhere on the account page, too.
For wemineltc.com, they use this format:
-u workername.1 -p workerpw
http://eu.wemineltc.com/gettingstartedHope it helps!