What height is needed for sieves when washing aggregates?

The correct answer is extra tall (6-8 inches) because when washing aggregates, the height of the sieves plays a crucial role in preventing overflow and ensuring effective separation of materials. Taller sieves provide sufficient capacity to accommodate the water and aggregates being processed. This additional height helps to control the flow of water and sediment, allowing for a more thorough washing process and reducing the possibility of losing fines or important materials through spills.

Standard height may not provide enough capacity for effective washing, while shorter heights could lead to issues with overflow and insufficient separation efficiency. Medium-height sieves might offer some benefits, but they still wouldn't provide the optimal conditions necessary for the washing process as effectively as the extra tall options do.