The existing villages of Pentre Halkyn, Halkyn and Rhosesmor grew rapidly in these times as more miners came to the area. New communities were developed as the villages grew, to house the newcomers. This resulted in the development of the villages and hamlets of Rhes-y-Cae, Moel-y-Crio, Wern-y-Gaer, Berthddu, Pant-y-go and Windmill. By the 19th century the lead mines were well developed and concerns arose necessitating mining techniques. This raised the problem of flooding due to the digging of deep drainage tunnels, with the most important being the Milwr tunnel that leads from Loggerheads to Bagillt.