The site navigation utilizes arrow, enter, escape, and space bar key commands. Left and right arrows move across top level links and expand / close menus in sub levels. Up and Down arrows will open main level menus and toggle through sub tier links. Enter and space open menus and escape closes them as well. Tab will move on to the next part of the site rather than go through menu items.
Surface mining involves removing soil and bedrock to reach resource deposits. The most common types of surface mining are strip mining and open-pit mining. Strip mining is used to extract shallow deposits. Usually, the deposits are just below the surface, under a layer of topsoil. This method does not require deep digging. Open-pit mining involves digging into the surface in a step-like pattern. Open-pits can also be referred to as quarries when they are also producing building materials.