In 1891 it looks as though poor Miriam is no longer with the family and you have to think the unthinkable. She must have been a twin to Moses as on the 1881 census they’re both shown as aged 9 months. It seems here that Moses the father has changed occupation to a coal miner. They are living at 23 Penyard, Penydarren, Merthyr Tydfil.
Moses Head 48 Coal Miner Merthyr Tydfil
Hannah Wife 46 Wife Merthyr Tydfil
William D Son 16 Coal Miner Merthyr Tydfil
John Jones Son 14 Son Bu bu? Merthyr Tydfil
Catherine A. 13 Charing Merthyr Tydfil
Moses Son 10 Scholar Merthyr Tydfil
Lewis Son 3 Scholar Merthyr Tydfil