Area: 24.21 hectares.
Description and Reasons for Notification:
This site comprises the large active quarry at Hingston Down and the adjacent disused mines and spoil tips immediately south and southwest of the working quarry faces. The quarry exposes a deep section through the south western corner of the Gunnislake Granite and associated mineralised zones. Mineral veins previously worked in the Coxpark section of Hingston Down Consols are exposed in the western faces of the quarry.
Hingston Down is the world type locality for the copper iron aresenate mineral arthurite. Native bismuth, molybdenite, scheelite, wolframite, arsenopyrite and fine specimens of opal and the beryllium silicate bertrandite have also been recorded from the quarry in addition to pegmatite minerals within the granite wallrock.
The mines at Hingston Down Consols worked several lodes which are mainly in killas at the surface but cross into granite at relatively shallow depth passing downwards from copper into tin mineralised zones. The mine’s spoil tip material is therefore highly variable and represents both tin and copper zones mineralisation with later-stage lead mineralisation filling open fractures in the tin-copper lodes. Good specimens of arthurite are obtained from the mine dumps along with many other interesting minerals including scorodite, carpholite, mimetite, pharmacosiderite, beudantite and the very rare lead minerals hidalgoite and carminite.
Mineralisation in both the quarry and the mine dumps is of Hercynian age and is associated with emanative centres in the Gunnislake Granite. Deepening of the quarry would expose more minerals of the tin zone and more pegmatite bodies within the granite.