Every time the pipe hits the bottom, some soil material is loosened and suspended into the drilling mud, which is continuously pumped out of the borehole by a valve, taking advantage of the same reciprocating movement.
On downstroke, new mud enters the pipe from beneath and the upper portion is expulsed.
For wells deeper than about 10 metres, and especially when heavier metal drill pipe is used, a lifting device is installed.
The basic method will work only in loose (clay, silt, sand and light gravel) soils, but adaptations of the principle are applied in a number of modern hand drilling methods, with valves either at the top or at the bottom of the pipe and with various models of drill bits for different soil conditions.
Well documented examples are the Rota-sludge, Baptist and some variants of the EMAS drilling methods.