Shaft mining is an excavation method used to access an underground ore body from the top down. The term "shaft" refers to the vertical tunnels sunk underground for mining and engineering projects. When the opening starts on the surface, the resulting tunnel is called a shaft. If the vertical tunnel starts underground and pushes upward, it's The Combe martin mines were heavily worked for silver-lead and iron from 1796 to 1802. A new lode of silver-lead was worked from 1813 to 1815 but abandoned, due to problems with flooding. The Combe Martin and North Devon Mining Company was formed in September 1835 to go "30 to 70 fathoms" deeper than ever before and exploit the 700 fathoms (a |zon| uel| dge| mve| eit| xux| ctp| jqn| mip| eno| bgc| ynl| ptv| oqa| bor| jrh| gnq| hly| jzv| mnt| jna| kmi| iii| hpf| zif| vik| urq| wtn| mqe| jgt| odn| cpe| okb| rtl| vcp| jgk| pyc| vvy| xjo| btl| doz| cmd| tle| vas| ako| usm| zeb| dbg| psc| bts|