A method of controlling a continuous multi-component slurrying process at an oil or gas well comprises continuously flowing substances for creating a slurry in response to a slurry flow rate factor and continuously flowing another substance for the slurry in response to a flow rate of at least a predetermined one of the other substances or the slurry itself. The method can include density control, slurry (tub) level control, and a combination of such controls. The method can operate in either closed loop or open loop manner, and control can be effected with either of two types of control signals depending on whether the controlled device is an integrating or non-integrating type. The method can also provide for bumpless transition between manual and automatic control.