From Outscape Wiki
The Mining Module is a small or medium ship module that allows a ship to extract usable mineral from Asteroid fields.
Depending on Tech level it mines at different speeds, the higher tech versions being faster of course. See this table here. Multiple Modules in a single ship or in a fleet will increase speed still further. It is perfectly possible to keep a Mining specialist ship on site and fleet merge it with Freighters to allow for more efficient transfer of resources.
See also Asteroid Mining