Abstract: This invention relates to a mobile apparatus for making aqueous bitumen and tar emulsions at road making and other surfacing sites. By providing a separate mobile storage unit for raw bitumen and mill mixing apparatus on a mobile water reservoir in which emulsifier liquid is to be made, which mill is adapted itself to draw fluid bitumen and emulsifier liquids in a pumping action, a compact and mobile plant is obtained relative to the capacity of the plant. The apparatus of the invention thus offers a feasable alternative to the transportation of ready prepared bitumen emulsions from fixed plants to distant road making sites.