That is mistaken.
If validly ordained priests and bishops splinter off into a new church (or an "old" church in this example), their orders don't dissipate. They are still priests and bishops. As such they can validly perform sacraments, including ordination.
Validly, not licitly, which is a different question.
So when the Old Catholic Church was formed, it consisted of validly ordained men. Inasmuch as they intend to do what the Church does, they can perform valid ordinations.
On men.
SD
Fine, I will ask you too to provide proof from the Vatican that they have valid orders.Inasmuch as they intend to do what the Church does, they can perform valid ordinations.
Since when did the Old Catholic church intend to do what the Church does? They ordain people who are in opposition to the Pope and Catholic teaching for goodness sakes.