A few thoughts...
Legions XIV Gemina, XX Valeria Victrix, IX Hispana/Iberia, II Augusta, took part in the invasion and conquest. XIV was withdrawn to continental Europe and that left XX re-sited from Inchtuthil to Deva (Chester), IX in Eboracum (York) and II at Isca (Caerleon). Interestingly, Deva's huge fortress may have been intended to support a two-legion invasion of the Dublin area of Ireland. My old friend Simon Ward seems to think so.
But...
At the date of Boudicca's revolt, the main Legionary forts were at Gloucester (XIV), Lincoln (IX), Exeter (II Augusta) and Wroxeter (XX Valeria, although with vexillations elsewhere).
British lead and silver certainly were known about before the Roman Invasion, but were only seriously developed much later. Given that the border to Suetonius Paulinus's Roman Britain was northwest of the Fosse Way, you can't claim to be lead-mining anywhere but the Mendips north west of Aquae Sulis (Bath). Mining by Rome in Fflint, Powys, Derbyshire and Cumbria, postdates the Boudiccan Revolt. Britain's main exports were poor-quality slaves (Britunculi), good grain and finer oysters and hunting dogs.