This paper evaluates the mechanical activation of mine waste (e.g. partially serpentinized olivine) using different milling machines, with a special focus on changes in microstructure and chemical transformation. The mechanical activation experiments were carried out using lab-scale high-energy planetary and vibratory mills, as well as a pilot-scale stirred mill, and laser diffraction, nitrogen adsorption, X-ray diffraction, and infrared spectroscopy were employed to identify mechanically-induced chariges in the mine waste. Direct aqueous carbonation was used to identify the best type of mechanical activation for carbon storage in the mine waste. The experimental results demonstrate that agglomeration of the particles takes place during extended milling in dry conditions, and that there is an effective mechanical activation limit for crystallite size reduction during dry grinding; the higher the milling intensity, the smaller the forsterite's crystallite size will be at the mechanical activation limit. Additionally, stirred milling in wet conditions produces the largest specific surface area, and vibratory milling in dry conditions generates the most disordered materials. The serpentine content was slightly dehydrated during dry milling and was not activated at all during wet milling. The stirred mill proved to be the most efficient form of mechanical activation vis-a-vis the direct aqueous carbonation process, followed by the planetary mill and the vibratory mill, respectively. (C) 2016 Elsevier B.V. All rights reserved.