Abstract: Muck and very wet material is removed from the surface of a moving conveyor belt by means of three scraper assemblies adjacent the head pulley of a conveyor belt installation. Each scraper assembly has a resilient, normally flat scraper blade with a tapered side, the opposite side being supported on an angle secured at each end to an operating lever which may be rotated by an air cylinder to engage the tapered side of the scraper blade with, and to flex the scraper blade against, the moving conveyor belt. The pressures in the air cylinders are adjusted so that the first scraper blade receives the greatest flexing force, and the second scraper blade a lesser flexing force, and the third scraper blade the least flexing force. This is done by supplying the air cylinders through progressively differently set pressure reducing valves connected to a common compressed air main.