In this paper we discuss properties of dense granular flows and elaborate on some properties of a model which generalises the classical plastic potential model using elements of the double shearing model. It is shown how the model is embedded into a Cosserat continuum model. The proposed model rectifies the ill-posedness of both the non-associated flow rule and the double shearing model and may be used for both granular materials and also for metals which possess a micro-structure which is capable of rotation.