overtime

What are an employees rights where mandatory overtime is issued? The main question is:Can an employer notify you 15 minutes before end of shift that you have to work mandatory ot? Is there unfair labor laws to help in this matter?

If you are a union member, this would be spelled out in your contract. If not, the employer can request you work overtime at any time. A considerate employer would give you a couple of hours, perhaps a day's, advance notice -- but there is no law against an employer being inconsiderate.