I find it difficult to understand that at the beginning of the 19th century miners children went to school but not many of them learned to read with an X. Unlesss my ancestors were a bit slower than most.
They may have attended for a short time for a basic education. Depending on the type of school, amount of fees and funds available, and number of pupils, writing with pen and ink may not have been included in the basic education offered. It might have been an extra for pupils who had learned to read and to write on slates and do arithmetic, and whose parents could afford to keep them at school longer and pay an increased weekly fee to cover cost of paper and ink. Pupils would receive an education appropriate to their "station in life".
Boys at an elementary church school in Preston, Lancs., 1823 were described as competent in writing on slates but very messy when trying to write on paper.
A report in 1840s into employment of children in mines includes evidence on education. Men in one Scottish mine made a compulsory weekly payment into a school fund. Conditions and educational standards in some of the schools for miners' children were found to be poor in the report. One schoolroom was so overcrowded pupils were unable to sit down. No chance of them learning to write.
I'd been at school for 2 years before I was taught handwriting with pen and ink. School attendance of some children in 19th century didn't last as long as 2 years.