Hundreds of people - many gathered on the hills around the plant - turned out for the demolition, part of work to dismantle the site by owners Cemex.
The top half of the chimney crashed down in a haze of dust. The whole of the structure was meant to fall to the ground, but some is still left and will be destroyed manually.
Former Cemex employee Dave Dark pushed the plunger that triggered the explosives after winning a Medway Messenger competition.
