Contamination is defined as: The introduction of extraneous aterial (normally deleterious) into a finished aggregate.
1. Use conveyors so foreign material isn't introduced by other equipment.
2. Minimize inventory buffer time increases chance for foreign material to overtake stockpile.
1. Drive equipment on stockpile.
2. Handle material more than once.
Degradation is defined as "The actual breakdown of individual aggregate particles due to abrasion and attrition during stockpiling and handling".
1. Recognize degradation in ramps or benches.
2. Minimize areas for ramps or driving on piles.
3. When possible blend degraded material with coarser material.
4. If degraded material doesn't look right – too fine, e.g.
The separation of a well graded production aggregate into individual sizes due to gravity.
1. Minimize drop height to limit overrun (variable height conveyors).
2. Use telescoping conveyor and build in windrows.
3. Load from end of pile.
1. Build stockpile with fixed height conveyors.
2. Build stockpiles with trucks, loaders or dozers.
1. Conical, most re-blending.
2. Windrow lifts, Least re-blending.
3. Layered, some re-blending.
1. Cone
2. Trapezoid, Simple layer
3. Windrow layer
1. The piles built as single or multi layer.
2. A layer can be pushed up by loaders.
3. 2nd most common method.
4. Material should not be placed closer than 2'-4' to the layer's edge.
1. Wheel Loader
2. Stacking Conveyor
1. Easy pile to build.
2. Must have axle system to allow movement radially.
3. Feed point is stationary.
4. Simple way of increasing volume with the same feed point.
5. Increases live storage.
6. Most consistent product to load out.
