Safe Quarry - Health and Safety Authority

PART 6 EXCAVATIONS INCLUDING (QUARRY FACES), TIPS AND LAGOONS
Figure 41: Significant Hazard – loose blocks above
working area
Figure 42: Significant Hazard – unstable stockpile
recovery face
Such site-specific guidance may be followed for
future appraisals, subject to limitations specified, in
preference to the generic guidance in the Tips and
Excavations Sections. Any such guidance should be
made available to those carrying out appraisals and
needs to be reviewed in the light of changes or new
information.
Properly validated analytical techniques for calculating
the hazard created by excavations, tips and
lagoons may also be used to determine the significance
of the hazard. Such techniques can also be
useful in prioritising work.
Where an appraisal of any excavation, tip or lagoon
identifies a potential significant hazard that can not
be rectified immediately, the operator must engage
a geotechnical specialist to carry out a site investigation
to establish if a full geotechnical assessment
is required.
Even where a significant hazard or potential significant
hazard can be rectified immediately by the
operator, it may still be necessary to have a site
investigation and/or a geotechnical assessment
carried out to identify what caused the development
of the hazardous condition, what if any effects
it had or may have on the overall stability of the
excavation, tip or lagoon and what actions are
needed to prevent reoccurrences.
Excavations
Where the appraisal of the excavation carried out by
a competent person identifies a significant hazard
that can not be rectified immediately a geotechnical
assessment will be required.The following list gives
examples of where this may be necessary:
(a) in the case of moderately weak or stronger rock
which is normally excavated using explosives or
saws -
(i) the vertical height of any individual face is more
than 20 metres, or
(ii) where multiple benches are present and bench
widths or the overall face angle may be
inadequate to ensure quarry stability; or
(b) In the case of weak or very weak rocks and
engineering soils, (for example clay or sand and
gravel deposits), where the vertical height of any
excavation exceeds 7.5 metres and the overall
face angle is steeper than a suitable angle to
ensure safety (see figure 44); or
(c) Irrespective of any excavation face height,
depth or angle, other factors, for example, the
geology, location or proximity of a tip, location
or proximity of infrastructure or private lands
means that there is a significant hazard as
described in that Section of this guidance.
Tips/Lagoons
Where the appraisal of the tip/lagoon carried out by
a competent person identifies a significant hazard
which can not be rectified immediately a geotechnical
assessment will be required. The following list
gives examples of where this may be necessary:
(a) in a wholly, or mainly, solid state and not in
solution or suspension (i.e. not likely to flow if
not contained); and -
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SAFE QUARRY GUIDELINES TO THE SAFETY, HEALTH AND WELFARE AT WORK (QUARRIES) REGULATIONS 2008