- gather regolith as raw material for a variety of substances
- fetch water ice from deeper layers
- shape caves for further usage
Mechanical shovels, or the smaller backhoes, are used for general digging work in surface operations. These can be used on Mars with modifications to take the extreme cold into consideration.
Tunnel boring machines
Tunnel boring machines are used to dig circular tunnels in rock of various quality. Their size varies from 1m in diameter to about 17m. Tunnel boring machines could be used to build entire habitats in a single pass, providing radiation protection through underground construction and, if the rock is of good enough quality, structure for the habitat. Many tunnels require lining, which increases the cost significantly. Tunnel boring machines use less energy than drill and blast techniques, that would require a continuous supply of explosives.
Most tunnel boring machines include a liner installation system, as well as rock bolt installations and grouting for gaps between the liners and the excavated tunnels.
Road-headers have rotary heads on the end of booms. They are used in mining and for non circular tunnels and underground stations.