FUNDAMENTALS

access to seam from surface

 

seam access types

   

Adits
 

Adits

Where there is a suitable, accessible outcrop available adit entries would almost always be preferred. Minimal work is required to gain access, usually only some minor excavation and stabilizing of the surface around the openings. Further, there is minimal sterilization of reserves and there is usually a very low gradient involved making the access suitable for rubber tyred vehicles or rail if desired.

If an adit can be created on the down-dip side of a potentially wet lease this could be a major benefit in handling waste water. This is a rare option, typically only being available where a coal seam runs through mountainous country and outcrops at several locations.

Adits driven off open cut highwalls are becoming increasingly common, artificial outcrops having been created by the open cuts. These are used to provide access to underground mines extracting the same seam as the open cut or additional deeper seams once the cost of overburden removal has become uneconomic.