Complex sentence: Armco and the Armco Employees Independent Federation (AEIF; an employee labor union) had a collective bargaining agreement in place in 2004 that required AK Steel to employ 3,114 workers, a "minimum base force guarantee".
Split into simpler sentences: Armco and the Armco Employees Independent Federation (AEIF; an employee labor union) had a collective bargaining agreement in place in 2004. As part of the agreement there was a stipulation that said AK Steel must employ 3,114 workers, a "minimum base force guarantee".