Under 30 CFR Part 48 subpart A, an individual who receives 40 hours of training and works for 12 months as an underground miner is considered an "experienced miner."
Under 30 CFR Part 48 subpart B, an individual who received 25 hours of training and works for 12 months as a surface miner is considered an “experienced miner.”
Mine Safety and Health Administration (MSHA) rules require that any experienced miner who has been away from mining for more than five years receive 8 hours of "experienced miner" training before returning to the mine.
If you do not have the 12 months of mining experience, you will need to receive 40 hours of "new miner" training. Some states have additional training requirements for miners. You may want to contact the appropriate agency in your state regarding specific requirements.
The MSHA web site has a listing of state agency contacts.