Designing a Tunnel: An Earth Science Design Challenge
Rocks are classified into three groups based on how they form: igneous, metamorphic, and sedimentary.
Rocks are classified by their properties: hardness, shape, size, texture, color, streak, mass, etc.
Determining a site to build a tunnel takes into account many factors such as cost, time, structure and landscape of the area where the tunnel is being built, materials available to the area, etc.
There are different methods to drilling through a mountain depending on its properties.