Abstract
Slope stability evaluations whether sourced from the works of Hoek & Brown, Janbu, Morgenstern & Price or in the use of canned software applications; not only require specific and often advanced geotechnical training, but in many cases are ‘black box’ approaches to many users, who accept the reported evaluations as ‘tried and true’. Few if any of these approaches consider the additional and compounding cyclic loading of mining equipment, operating close to the edge of such broken rock and soil structures as dumps, fill ramps and blasted rock elevated positions for backhoe ‘honeypot’ configuration mining operations loading trucks. The driver behind contemplating the impact of cyclic loading operations is the simple fact that we still encounter catastrophic incidents such as hauler and excavator roll-overs, as the bearing capability of the underfoot and adjacent broken/blasted rock slope, to this incremental operational cyclic loading activity, is exceeded.
This presentation will outline an approach (developed from Hoek-Brown stability charts) by which both engineers and operational field leaders can quickly and simply evaluate an operational safety factor for safe mining fleet operation, and make appropriate decisions on maximum dump and ramp fill heights, relative to the (seasonal/blast quality/rock) dumped slope angle and broken rock frictional dominated strength; and most importantly the additional cyclic loading imparted from the operating assets on such adjacent surfaces. A simplified ‘laminated glove-box card’ is introduced to allow field supervisors to identify when a change in operating conditions have the potential to both reduce the safety factor and as such should require a review of the dump/ramp/operating surface design before operations can safely resume.