Clarks Have modified several excavators from diesel to air powered. The first machine modified was for an underground bin excavation. The excavator modified was a Case 3T machine which included fitting an air safety circuit as all electrics and diesel supply was removed. The pneumatic change made it possible for the machine to operate in an underground coal mine without the issues of toxic fumes and explosive risks. Clarks have also modified a 1.3T JCB excavator and a Kubota U17-3.