Mining Topic: Slope Stability

What is the health and safety problem?

Whether underground or on the surface, unexpected rock movement can cause injuries and can potentially result in a mine catastrophe. Even relatively shallow strip mines and quarries can experience devastating consequences from slope failure. Open-pit mines are deeper than ever before, and because rock mass strength at these large scales is difficult to evaluate, massive slope failure can occur with little warning.

What is the extent of the problem?

The injury and fatality rates from surface mining rock fall accidents are significantly less than from underground rock falls. Over the last 5 years there were 7 fatalities caused by highwall or slope failure. However, these infrequent events have the potential for catastrophic failure that could affect many mine workers.

How is the NIOSH Mining program addressing this problem?

The NIOSH Mining PRogram has examined (1) design of augering patterns for safe mining of coal from highwalls has also been examined through numerical modeling, analytical and empirical techniques; and (2) technologies to identify zones of weakness in a mine slope and determine the likelihood of slope failure.

What are the significant findings?

NIOSH Mining developed and released a software package, called ARMPS-HWM, for design of extraction patterns in highwall mining. A software package for assessing bench stability in highly fractured rock slopes was also developed, examining plane wedge, step path and wedge failure modes (Bplane, Bstepp and Bwedge – respectively). A number of developing technologies with potential for revealing zones of weakness in a mine slopes have also been examined. These experimental methods may one day contribute to remote sensing of potential areas of weakness in mine slopes.

What are the next steps?

NIOSH is monitoring the industry to determine if there is an upswing in associated hazards.