I do not think comparing peasants with coal mine workers is a fair comparison.
However!
After a bit of googling, I found out that the average life span of coal mine workers in the 18:th century was between 30-40 years, and the average life span of peasants around the year 1100 was 30-35,
Despite comparing people working outside all their lives, with the worst possible jobs in the 19:th century, the coal mine