Pennant / Penrhyn Estate
Richard Pennant inherited the Penrhyn Estate in 1781 and consolidated its scattered workings into the vast Penrhyn Quarry, investing in roads, a railway and Port Penrhyn to build it into the world's largest slate quarry; the Pennant family's ownership, and its harsh labour relations, culminated in the three-year Penrhyn Lockout of 1900-1903, Britain's longest labour dispute.
Mines operated
| Mine | Region | Years |
|---|---|---|
| Penrhyn Quarry | Gwynedd | 1765–1965 |
Record created: 20 August 2026