The owner of land through which a public road has been opened usually retains the ownership of any minerals which belonged to the owner at the time of the road opening. This applies whether the road was opened by common law, dedication, statute or reservation in a Crown grant.
A public road created by resumption does not affect the minerals under the road except where the land resumed is described to a depth. Where the land resumed is not limited in depth but the dedication is limited to a depth below the surface, the registered proprietor is entitled to all the minerals under the land resumed.
Where a road is reserved in a Crown Grant, the grantee acquires no interest by reason of such ownership either in the soil of the road or the minerals under it.
The dedication of land as a public road does not affect any rights of any person with respect to minerals below the surface of the road - see s.146 Roads Act 1993 and Minerals page.
For further information - see Baalmann & Wells [para. 318].