This article presents the current status of the H2020-ROBOMINERS project with focus on the prototype to be developed. The aim of this project is the development of a small-scale mining robot, which will be capable of exploring difficult to access deposits with the ability of selective mining underground, under water, and in slurries. Considerably low weight and power are challenges to be overcome. Environment-friendliness is secured by powering the entire robot water-hydraulically. Core element of the robominer is the main module, in which the locomotion and powering system will be implemented. Additional elements in the robot are sensors for navigation and perception and a production tool to excavate small amounts of material. The locomotion system consists of an Archimedes-screw mechanism, which can be extended in radial direction and used as grippers inside a tunnel to increase its traction capacity. Selective perception tools help the mining robot navigate in harsh terrains and find the ore. A small-scale longitudinal part-face cutter head has been selected as an excavation tool. This cutter head has been tested extensively in the laboratory by performing cutting tests with several rock samples. The performance allows a continuous excavation of soft rock material (successful tests with reasonable excavation rate up to a uniaxial compressive strength of 30 MPa). The mined ore is then slurrified and transported to a processing station. On-board analysis equipment using specializsed sensing systems allows the robot to analyse the slurry composition in real-time. The demonstration and final test of the full-scale prototype are planned in an open-pit oilshale mine. Eventually, the project will serve as a guideline for future mining robots including feasibility studies of different robot designs, potential mine layouts and mining scenarios as well as various excavation tools for different rock conditions.