Changes

A drift mine is a type of coal mine that is driven horizontally into [[coal]] that is exposed or accessible in a hillside.  

A '''drift mine''' is a type of coal mine that is driven horizontally into [[coal]] that is exposed or accessible in a hillside.  

In a [[hydraulic mine]], high-pressure water jets break the [[coal]] from a steeply inclined, thick coal bed that would be difficult to mine with the usual underground methods. The [[coal]] is then transported to the surface by a system of flumes or by pipeline.  

In a [[hydraulic mine]], high-pressure water jets break the [[coal]] from a steeply inclined, thick coal bed that would be difficult to mine with the usual underground methods. The [[coal]] is then transported to the surface by a system of flumes or by pipeline.