How many years are the special jobs of foundry workers?

Engaged in forging, casting and other high-temperature and underground operations, you need to work for 9 years. For this special type of work, foundry workers need to work for 9 years. This is a special type of work with strong working environment and heavy physical load. In order to protect the physical and mental health of workers, relevant laws and regulations have made certain provisions on their working years.