Cassiterite Shaking Table: Gravity Concentration (2D)

This 2D companion replaces the 3D version's decorative process-flow diagram with a real particle-scale model of a shaking (Wilfley) table. Each grain fed onto the deck carries a true mineral density — cassiterite at 6,900 kg/m³, or the quartz/silicate gangue it's mixed with at 2,650 kg/m³ — and Stokes' law gives it its own terminal settling velocity in the water film. That velocity sets a "contact fraction": how much of each shake cycle the grain spends settled into a riffle trough versus suspended in the moving film. The table's asymmetric reciprocating motion only advances settled grains along the riffles toward the concentrate launder, while the cross-flowing wash water and the deck's cross-tilt sweep suspended grains sideways toward tailings — the same differential-transport principle real gravity-concentration tables use, and the reason it works at all is the concentration criterion CC = (SG_heavy − SG_fluid) / (SG_light − SG_fluid), shown live in the readout panel.