* Company developing new process to extract titanium dioxide * Plant feasibility study due in the next few months * Aiming to commission first plant in mid to late 2014 By Allison Martell TORONTO, March 3 (Reuters) - The TSX Venture Exchange recently hailed Argex Titanium Inc as one of its top-performing mining issuers, but the Canadian company is in no rush to actually build a mine. Instead, Argex is preparing to construct a plant where it can produce titanium dioxide - use