5 5 4 Work Schedule for Coal Mine?

Question

Has anyone ever heard of the 5 5 4 work schedule at the coal mines? Please help!

Answer 1

Educated guess,

As a mining operation is likely a 24 hour a day 365 day a year operation the schedule would be:
5 day shifts followed by 5 afternoon shifts followed by 4 midnight shifts with 1-3 days off between shift changes

For many years in the iron mining industry I worked 7 afternoons with 2 days off 7 day shifts with 1 day off and 7 midnight shifts with 4 days off.