I just double checked the statistics extracted from the 1871 census - included in the list of towns in Ireland with population 120 or greater is Cloanmines, Co.Cork, population 882. So a reasonable size...
I think the 'mines' part of the town name may have derived from local resources in the parish - apparently Asbestos, lead and copper ore, and also iron ore.
see the Lewis Entry for the parish :
Kilnamannagh civil parish (Bere/Bear Barony)
see also 1st Ed. OSI Map (c1837) showing mines, foundry, Bearhavan copper mine, engine houses, various works, powder magazine etc :
part of Cloan townlandS.