Abstract: A high pressure jetting apparatus has an abrasive cutting nozzle, a hopper supplying abrasive material, a container for mixing abrasive and a carrier liquid at a point remote from the nozzle, and a closeable conduit for conducting the mixture at high pressure from the container to the nozzle. When the closeable conduit is closed an endless circulating path is formed between the container and the hopper to charge the container with abrasive from the hopper and carrier mixture. The mixture is conveyed under pressure from the container to the nozzle when the inlet and outlet conduits from the hopper to the container are disconnected and the closeable conduit is open.

Abstract: A system for supplying a slurry includes a hopper having a lower portion tapering to an outlet at its lower end. A liquid is supplied to the hopper interior along a wall of the lower portion in a direction having a horizontal component. Particulate material feeding from a main portion of the hopper into the lower portion becomes entrained in the liquid, thus forming the slurry.