Pan mixer operation: which mixing mechanism best describes the action in a pan (muller) mixer used for foundry sand and similar materials?

Introduction / Context:
Pan (muller) mixers are used to prepare cohesive mixes like foundry molding sand by combining sand, clay binders, and water to achieve uniform plasticity.

Concept / Approach:
Mulling involves rolling, smearing, and compressive shearing under heavy wheels and scrapers, thoroughly coating particles with binder. This differs from simple kneading (typical of dough mixers) and from high-shear dispersion used for liquids or slurries.

Final Answer:
Mulling