Conventional hydraulic mining has shown the ability to mine coal at a rate in excess of 3 000 tons/shift, but is limited in application to seams within favourable geology and, for higher production rates, steeper inclinations. The potential advantages of water jets for mining have led to the design of a Hydrominer for the more standard seam currently mined. In order to accommodate the less favourable conditions, the jet pressures have been increased and the flow rates decreased to minimize the water effects on the surrounding geology. In order to simplify to progress of such a machine from the drawing board through the proof of concept tests to the first trials in an underground face, the design has been built around an adaptation of the BJD Supermatic shearer power pack. This paper describes the development of the machine from the first conceptual design through to a field test of the first cutting head in an opencast test site. Problems associated with the design of the head, identified in this trial, are discussed with the proposed solution. The paper concludes with a brief discussion of the tests carried out using the second generation of the Hydrominer cutting head. These tests were carried out at the US Bureau of Mines test facility at Bruceton, PA, in an artificial coal seam.