PURPOSE:  To reduce the risk of injury from rock falls by removing the barriers that limit the use of surface control technology. The barriers include: a lack of understanding of the geologic conditions that lead to small rock falls, a lack of knowledge about successful surface control techniques, inadequate installation procedures and equipment, lack of engineering design guidelines, and support and production costs.

RESEARCH SUMMARY:  Each year, about 500 reported injuries (and usually 1-2 fatalities) result from relatively minor falls of rock from the roof in coal mines. These injuries occur in areas that have been supported and should be safe. Various surface control techniques are used in mines to control minor rock falls of the roof. However, current technologies are often ineffective, and they can be expensive and time-consuming to install. As a result, mine operators are often reluctant to use these technologies. This project is designed to reduce barriers to the use of surface control and improve the effectiveness of the surface control systems.

Research has identified the use of welded wire screen as the single most effective surface control to prevent rock falls between bolts. Dramatic reductions in injuries have been documented at mines that use screening on cycle. Routine use of screen is not common in coal mines. A number of installation “best practices” have been documented and are now being actively promoted in a series of underground screen installation demonstration sites. Another barrier to the adoption of roof screen is the perception that it is difficult to install and may, in fact, cause injuries. An ergonomics study using a simulated coal mine is being conducted to determine the ideal loads and positions related to transporting and installing screen. A training video that documents the benefits of roof screening has been developed and is currently being distributed.

Another project goal is to help identify rock types that are most prone to rock falls. Rock that is sensitive to moisture can deteriorate, swell, and fracture. Laboratory testing and down hole geophysical methods have shown promise in identifying weak rocks.

Some expected outputs from this work are:

1. Personal Bolter Screen technology for rock fall prevention
2. Training video: “Make It Safe with Roof Screen.”
3. Ergonomic “best practices” for roof screen installation.
4. Suggested procedures for identifying weak, moisture sensitive rock prior to mining.