fbpx

GEOTECHNICAL ROCKFALL MITIGATION & PROTECTION



SCALING AND BLOCK REMOVAL


Our Drill & Blast Team has 20 years of experience removing, shaping, and re-profiling countless rock faces across the country. As scaling work is an often vital part of most geotechnical projects, our safety systems and risk analysis procedures have been internally perfected over decades to mitigate the risk of hazardous environments. In situations where wildlife may be at risk, we can work with our conservation team to minimise the impact and relocate animals if need be.

We are specialists in micro-blasting and use exact amounts of explosives to produce accurate fragmentation and minimal fly rock. When this needs to occur over a road or access way, we have people and traffic management procedures that can be put in place to mitigate the impact on the public.

Our services include:



  • Hand and Rope Scaling
  • ‘Airbag’ Jacking
  • Expanding Cement Grouts
  • Removal of Unstable Rock Features and Cliffs using High Explosives under EPA Class 1.1 and Nonex (low explosives) under EPA class 1.4.
  • Public Safety Management
  • Environmental Management
  • Clearing and Disposing of the Blast Debris

DEVEGETATION


Root networks of bushes and trees can be a contributing factor to the destabilisation of slopes and cliffs. As the networks grow and expand, they can slowly break a solid formation apart, resulting in an increase of loose rocks and soil.

Abseil Access can provide devegetation services to clear slopes and rock formations in preparation of a broader stabilisation plan. If large tree felling above a carriageway is required, Abseil Access can also assist local government in creating a traffic management plan to minimise the impact on commuters.

Our Slope Stabilisation Team utilises a well-planned combination of rope, specialist, and mechanical access solutions to ensure the safety of both our team and the community.



  • Rope Access Surveying
  • Specialist & Helicopter Access
  • Debris Removal
  • Loose Rock Removal
  • Weed Eradiation
  • Ground Preparation and Devegetation
  • Traffic & Safety Management

DRILL AND BLAST


We have over 20 years of experience in this specialised and demanding field. We are certified for the use of high explosives under EPA Class 1.1 and Nonex (low explosives) under EPA class 1.4. Our shot firers are certified and meet the new Health and Safety at Work (Hazardous Substances) Regulations 2017.

We are specialists in micro-blasting and use precise amounts of explosives to produce accurate fragmentation and minimal fly rock.We use HD video for post-blast and possible misfire analysis on all our blast projects. Our clients include the Department of Conservation, Councils throughout New Zealand, Kiwirail, Radio New Zealand, and NTZA.

Areas of specialist expertise include:



  • Certified for High Explosives Under EPA Class 1.1
  • Micro-Blasting Specialists
  • Rope Access Drill and Blast
  • Benching
  • Boulder Cracking
  • Demolition
  • Safety Management

ROCKFALL BARRIERS AND ATTENUATORS


Abseil Access assesses each project individually, and in certain geological situations, it may not be practical, feasible or cost-effective to implement active rockfall mesh. In these situations, Rockfall barriers and attenuators are excellent alternatives.

Rockfall barrier systems are placed as a braking apparatus for falling rock or debris and can be modified explicitly for various situations such as motorways, industrial infrastructure, and private residents.

Rockfall attenuators are a combination system with the braking properties of a rockfall barrier and the reduced maintenance requirement of active rockfall mesh. Abseil Access commonly implement attenuators systems on large slopes where there is sufficient space.



  • Rope Access Surveying & Planning
  • Ground Based Drill & Anchor
  • Rock Face Drill and Anchor
  • Grouting
  • Micro Piles
  • Attenuator Design & Install
  • Rockfall Barrier Design & Install
  • Traffic & Safety Management

PROJECT EXAMPLES

JOHNSONVILLE LINE ROCKFALL MITIGATION

The Johnsonville line cuts up through the Ngaio gorge through 5 tunnels. Over the past 15 years, Abseil Access has helped Kiwirail reduce rockfall on various sections of the line and over the tunnel portals.

In 2019 AA conducted the 6th such project, installing active mesh and anchors between tunnels 1 & 2. The netting was installed first to reduce the chances of rockfall during the drilling phase. The team then use an A-frame drill rig to drill and install 32mm and 25mm diameter GRP anchors.

NGUARANGA GORGE ROCK FALL MITIGATION

Abseil Access successfully delivered an SH1 Ngauranga Gorge rockfall mitigation project during an extended SH1 lane closure over the New Year holiday period.

This major project required 352m of ground-based, suspended A-frame and excavator mounted drilling, as well as rolling lane closures on the state highway for seven helicopter mesh installation operations. Abseil Access completed this scope within the allocated 2-week switchyard isolation period with no damage to the critical high voltage equipment.

PEACOCKS GALLOP ROCKFALL PROTECTION

The 2011 Christchurch earthquakes caused the cliffs above Peacocks Gallop in Sumner to suffer significant rockfall activity, resulting in the cliff retreat and edge collapse.

In 2016 Protranz began earthworks at the base of the cliffs and engaged Abseil Access to carry out rockfall protection work on the volatile area. Our crews spent six weeks scaling the top 15m of the cliffs to mitigate the imminent risk of rockfall impacting earth-moving works below. Several Hundred tonnes of unstable was remove using airbags and hand tools.

CLIFTON HILL ROCKFALL PROTECTION

Christchurch City Council engaged Abseil Access to stabilise cliffs that had suffered movement and collapse during earthquakes. Working above a live road that accommodated 20,000 vehicles per day, a strict traffic management plan had to be created. The team removed vegetation and smaller rocks, then utilising a helicopter to lift forty-five 170kg rolls of rockfall netting to the top edge of the cliff, allowing the abseilers to position the netting on to the top cable. The mesh was secured with 19mm galvanised wire cable.

WAIMAKARIRI BLUFFS, ARTHURS PASS

Abseil Access was engaged by the New Zealand Transport Authority to carry out rockfall mitigation works on two sections of the Waimakariri Bluffs above SH73 at Arthurs Pass. Abseil Access first performed scaling work and removed features that could hinder future work to make the area safe for the drill team. 6500m­­­2­­ of HR Rockfall Drape Mesh was then installed across the two sites by rope access personnel.

Using a combination of self-drilling and open hole anchors, our 14 person team successfully completed 1290m of Drilling and anchoring.