Nodding donkey
A nodding donkey is the overground drive for a submersible pump in a borehole. A nodding donkey or horsehead pump is usually driven by an electric motor and 'nods' at a regular rhythm. Depending on the size of the submersible pump, it produces between 5-40 litres of oil-water mixture at each stroke. There is a 2-inch wide metal rod that disappears into the ground, hundreds of metres or thousands of feet down into the oil reservoir. This system is also commonly referred to as a 'beam pump' or 'rod pump'.
