What is drift mining and how does it work?
Drift mining involves working coal seams accessed by adits driven directly into the surface outcrop. This method follows the bed of ore rather than intersecting it at an angle like shafts or crosscuts do.
Questions about Drift mining
Short answers, pulled from the story.
When did early miners start digging exposed coal in the British Isles?
Records show coal digging occurred in Durham, Northumberland, Nottinghamshire, Derbyshire, Staffordshire, Lancashire, Gloucestershire, Lothian, and Wales during the 13th century. By the 20th century, drift mines still operated in Derbyshire, Yorkshire, Cumbria, and Wales.
Where was the Boulder-Weld Coal Field located and when was it mined?
The Boulder-Weld Coal Field beneath Marshall Mesa in Colorado was drift mined from 1863 until 1939. Measurements taken in 2003, 2005, and 2022 revealed an active coal-seam fire there that was investigated as a possible cause of the 2021 Marshall Fire.
How did drift mining methods help recover gold in the Nome mining district starting in 1899?
Miners tunneled into deep placer deposits bringing out high-grade gravels to be washed at spring thaw because water to wash gold from placers was not available in winter months. Most ground in Nome consists of permafrost so miners recovered much gold buried under the frozen layer by following horizontal tunnels along bedrock surfaces.
Why do drift mines in eastern Kentucky face roof collapse issues?
Drift mines in eastern Kentucky face roof collapse due to hillseams within 100 feet of the portal. Hillseams are weather-enlarged tension joints occurring under 300 feet or less of overburden that form by stress relief and tend to parallel topographic contours and ridges.