- You may be looking for Captain Hopper.
A hopper was a storage unit on board sandminers.
While inside the storage unit, the door closed behind the Doctor and it began to fill with ore. The Doctor had to use a snorkel to save himself from suffocating. While looking at the readings, SV7 observed that there was a high level of impurity in one of the hoppers, leading it to open the unit and discover the Doctor.
Vocs 35 through to 40, under the command of Capel, searched the hoppers looking for humans. After they had done this, Leela and Lish Toos hid in one while passing through to the control deck. (TV: The Robots of Death)