Abstract
Mines in the Western United States have had limited choices for standing support. Wood cribs were often too soft and unstable. The introduction of the Can support in the early 1990s provided an effective alternative, and it remains the dominant form of tailgate support. Water-filled prestressing cells are now used to cap the Can and preload it to provide an active roof load. The Cluster Prop, consisting of three timber wedge props bundled together, provides more capacity than an equivalent-sized Can support and improves transport efficiency. However, the Cluster Prop is less stable and does not maintain a consistent load throughout its loading profile. Pumpable roof supports are another alternative support, but they have not been proven in high-deformation environments. This article compares the performance characteristics of these various support systems.