Oxygen is very useful in mining like in gold mine, manganese mine. Generally oxygen is as oxidizing agent or fuel to enhance the chemical reaction efficiency and speed.
Take gold mining for instance, Oxygen is used for improving leaching efficiency and leaching rate. Gold mine exploited crude gold with slurry, and puts the mixture in big tanks with water. The mixture is stirred to increase the separation rate. In this process oxygen is required to put in to increase the separation efficiency and separation rate.
Generally the separation with O2 is 2-5 times of that without O2.