The Hicom 120 mill is a high intensity, compact, grinding mill of novel design. This technology has been under evaluation by the De Beers Group for a number of years. Based on positive results from pilot plans test work, an industrial evaluation programme was embarked upon at Venetia Mine from August 1999 to November 1999. The testwork programme was designed to produce reliable data for the mill's comminution characteristics, particle residence rime distributions, and engineering soundness. The testwork was conducted with -25 +4 mm and -8 +4 mm kimberlitic ores of varying hardness. The Hicom mill's response was sensitive to the ore hardness, with throughputs ranging between 4 t/h - 8 t/h, production of -1 mm ranging between 18%-46%, and specific energy requirements ranging between 17-66 kWh/t of -1 mm material produced, for -25 +4 mm feeds. The particle residence rime distribution tests showed that the load segregates into a particle size order, and the results indicate that the top-size material (25 mm) has a low probability of exiting the mill. The mechanical reliability of the mill was good, and the unit can be considered to be very robust. The liner wear rate was unexpectedly high, with liners lasting approximately 20-80 hours depending on the ore hardness and feed size