A haulage ramp is the main method of open pit mine access and haulage. The haulage ramp allows the haulage trucks and other mine support vehicles to enter and exit the open pit production levels.
Access haulage ramp failure refers to the collapse of a portion of the open pit haulage ramp system. Haulage ramp failure may range from small failures to substantial failures that renders the pit bottom completely inaccessible.
Generally, the open pit mines are designed with two access ramps. However, it is quite common to have only one access haulage ramp into the production levels of the open pit mine. Recently, there has been cases where the sole access haulage access ramp is threatened due to slope instability. The technical details of the access haulage ramp instability is beyond the scope of this article. This article will only focus on the remediation measures after the access haulage ramp has already failed or in the initial stages of instability.
In a large number of cases, major access haulage ramp failures have been attributed to large-scale geological features such as shear zones, major faults and contact zones that are aligned parallel to or in an unfavourable orientation to the excavated slope. In a small number of cases, major access haulage ramp failures occurred due to inadequate mining practices and ineffective mine dewatering.
Access haulage ramp stabilisation refers to the construction and/or installation of structural elements used for shoring and remediation of collapsed access haulage ramp. Hoff Geotechnik offers a few options for access haulage ramp stabilisation systems. These include a combination of the following:
- Deep-grouted cable anchors
- High tensile pinned wire-mesh
- Fibre reinforced shotcrete
- Mechanically stabilised earth walls (MSEW), this is used to rebuild an already collapsed ramp.
The selection of the most efficient access haulage ramp stabilisation system is based on a number of important factors such as the results of the slope stability analyses, the ultimate factor of safety (FoS) as well as access for the drilling and construction equipment.
Get in touch with us to know more about our offers for mine access ramp stabilisation.
Ernest Rankhododo (MSc. Eng.)
