Abstract

    For the last several decades, shaft sinking has not seen significant levels of innovation with respect to methodologies and technologies. Conventional drill and blast for blind shaft sinking has been the standard, with only minor adaptations to the equipment in efforts to increase both productivity and safety.

Several examples of mechanized shaft sinking systems, such as roadheader-type machines have been seen in Europe and Russia in the 1980s. These, however, were successful only in specific soft rock ground conditions such as rock salt, with the major challenge being the mucking of the excavated rock from the face to the bucket. The V-mole technology, developed by Wirth, Germany, was used successfully both in hard and soft rock in Germany and Southern Africa. Nevertheless, it could be deployed only for mine extensions as the shaft had to be undercut to drill the pilot hole, and the muck had to be hoisted through the existing mine infrastructure.

The Tunnel Boring Machine (TBM) manufacturer Herrenknecht AG developed in the first decade of this century, the Shaft Boring Roadheader (SBR), which was first used to sink the two shafts of the BHP Jansen project in Saskatchewan, Canada. The second generation machine, developed together with Redpath Deilmann for the Slavkaliy Neshinsky project in Belarus, achieved a sinking rate 3 of m/day on average, with peak performances over 7 m/day in medium to soft rock. The key to achieving these performances was, amongst other aspects that the liner installation occurred concurrently with the excavation. The high performance Pneumatic Mucking System to hoist the rock from the bench into the buckets was also instrumental to the successful achievements.

The SBR system does not work in all ground conditions, specifically ground above 100 MPA or in severely varying rock conditions. What this says is, that even if the mechanized shaft sinking systems can be further developed, the demand for drill and blast shaft sinking will remain, until a solution for hard rock mechanized sinking is developed. Even when such innovation is market ready, each shaft sinking approach must be evaluated for safety, productivity and cost. Efforts are afoot to develop hard rock machines, with testing in progress, but these come with their prototype risk of performance, complexity and cost.

On a number of recent shaft projects, Redpath has deployed an innovative approach to sinking, with the core element being a hydraulic shaft mucker, connected below the bottom galloway deck.

With a continued focus to optimize drill and blast approaches, Redpath Deilmann developed a new generation hydraulic shaft mucker, capable of remote drilling and mucking, and thus allowing concurrent liner installation during these critical path cycle tasks. The new mucking system, the RD SE100, is semi-automated and equipped with cameras and designed to be operated by remote control from the galloway  from surface or even from a distant location.