Interior of Marston Salt Mine, Northwich, Cheshire, England, c1880. This shows how pillars of rock have been left to support the roof. At this date (1880) the mine had been excavated to a height of 16 ft (5m) over approximately 40 acres (more than 16 hectares). From Science for All by Robert Brown. (London, c1880). | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Heritage Images / Ann Ronan Picture Library |
Bildgröße: | 3820 px × 2751 px |
Modell-Rechte: | nicht erforderlich |
Eigentums-Rechte: | nicht erforderlich |
Restrictions: | - |