The objective of this thesis is the redesign of the existing ContBlast unit to a Lining-While-Charging (LWC) unit. The thesis is integrated in “SLIM”, a H2020 project of the EC, and there the task is specified as followed: “Design of a ContBlast unit for lining while charging (LWC) with considerations for placement of detonator and primer. Manufacture first prototypes of ContBlast unit with 3D printing, up to 40-50 units Drilling of either 40-50, Ø76 or 89 mm, 15-20 m deep blastholes, some if possible in wet ground Charging with ContBlast units and MUL-BBK emulsion pumping unit and explosives from Austin powder. Checking for emulsion leakage through rise of emulsion column during gassing. Blasting of holes while checking for detonation failures. Evaluation of design of ContBlast unit and redesign according to experience” (Executive Agency for Small and Medium-sized Enterprises, p.21) As the ContBlast unit is a “prototype for explosive charges centered in the borehole for the use of cautious blasting in underground applications” (Ivanova R. 2011, p.1), the purpose of this unit is its application for cautious blasts. However, the LWC unit should support production blasts in wet or jointed borehole conditions using emulsion explosives. The redesign of the unit started with the analysis of storage possibilities of a plastic hose inside a protection container and the development of a 3D printed device, which supports the unfolding mechanism of the plastic hose and prevents the advection of emulsion into the plastic hose storage area. Lab tests with water and field tests with emulsion as filling medium were conducted to ensure the LWC unit capabilities. Stress tests were performed with the plastic hose to determine the strain resistance against the static load of the emulsion, the rock load and the load while unfolding. In these test series a lot of emerging problems could be examined and solved. The design of the connection between charging hose and emulsion-pumping unit, which withstands the pressure conditions of the pumping process, completes the development.