The Swedish Boliden group, the largest Scandinavian industrial group in the fields of sulphide ore mining, non-ferrous metal smelting and the production of inorganic chemicals is faced with the same difficulties as in other industrial countries - dwindling deposits of high-grade ore, growing requirements of environmental protection, rising energy costs and a high cost situation. The pressure of having to continuously adapt processing technique to the poorer and more strongly growing deposits determines the current activities in the area of preparation technique. The programs of development have recently been focused on the particularly pressing problem areas of autogenous grinding, recovery of precious metals, dewatering and process control. The work carried out to this time is reported on and an outlook is given on future developments.