Had trouble locating the mill, since it is called Cwmdawe mill. See the map:
https://historicplacenames.rcahmw.gov.uk/placenames/recordedname/d9b5a407-7743-455f-a5fd-6859a53dc7f4Classed as a corn mill.
On the 1891 census the miller is widowed John Davies aged 63 with his 2 daughters Margaret and Ann. The address is Cwmdawe Mill, Bryndifyr, Pencarreg, Lampeter, Carmarthenshire, Wales
RG12 Piece 4552 F30 p11 sced 39
Margaret is the miller there in 1901 & 1911 (aged 68)
They were at Cwmdawe farm next to the mill in 1881, John widowed with daughters but farming 84 acres, the miller being John Jones aged 31 who also farmed 15 acres with his wife and their 3 little children, first born 1875, so they must have married before moving in to the mill by 1881, since they are not there in 1871.
David Davies and wife and his step daughters are at the mill in 1871, he is 48 and is miller and farmer of 30 acres.
Evan Davies aged 50 with wife Jemima and 3 sons and a farm servant are at the mill but farming (no mention of being a miller)
Haven't yet found the mill on 1851 / 61.