Seafloor deposits are a very promising source of mineral ore for the near future, discovered over the last 40 years. In particular, Seafloor Massive Sulphides (SMS) are very high grade hydrothermal mineral deposits distributed on the mid ocean ridges, arc and back arc basins in the deep confines of the world oceans. The Technip Subsea Mining R&D program is now entering its 6 th year with a clear goal of developping the necessary technologies to recover these sea deposits in an economical, safe, and environementally friendly way. The current paper describes the current field development that Technip is focussing on. This concept is based on the use of flexible riser anchored to the sea bed and positionned into a wavy shape in order to allow production in rough seas. This concept also focuses on the use of a grabber able to cut and collect the SMS chemineys from top to bottom. The innovative aspect of this concept is to maintain the pumping system on the topside vessel for efficiency and maintenance purposes. One the key unit to be developped is the Subsea Crushing and Feeding Unit (SCFU) that will allow collecting and crushing the material from the grabber content, as well as feeding the crushed material into the high pressure flow circulating inside the riser and jumper network. On this task, Technip has teamed up with ith MMD sizers, a leading crushing equipment supplier for the Mining Industry, to integrate into a subsea structure a sizer and a feeding unit self regulating the transfer of crushed material into the high pressure flow.