The Ironstone mines in the 'Heads of the valleys' were generally levels or drift mines, as the ironstone outcropped or was close to the surface. Some seem to have been worked as surface quarries or 'patches'. There are two former Coal and Ironstone pits shown on Old-Maps at 311000 209300 east of Bute Town, at the head of the Rhymney valley, for example, and slightly north of there, 311600 210200 south of Tafarnaubach there is 'Quarry Ironstone and Coal'. http://www.old-maps.co.uk/ The site has changed in recent weeks and takes a bit of getting used to in its new format. Jeff