Professor Sorenson led an eight-man expedition to Zeta Minor in search of alternative power sources as the Morestran sun was dying. The professor believed his discovery of the minerals to be the greatest scientific feat in history.
The presence of the minerals on board the Morestran probe ship prevented it from taking off, with the cyclostimulators failing. The anti-matter creature was the cause of this and staged an attack on the ship.
The Doctor took some minerals with him in a small contained when he went to negotiate with the creature. This allowed him to re-emerge from the anti-matter dimension. He promised the creature that he would return the minerals.
The majority were removed from the probe but Sorenson secreted some. His proximity to them saw him become infected. His brain cells were killed and he reverted to, in the words of the Doctor, "the level of a brute". Using his TARDIS, the Doctor returned the minerals and Sorenson to the anti-matter dimension. The promise fulfilled, Sorenson was released and restored to his former self. (TV: Planet of Evil)