Rockfall Assessment

March 31, 2015

In 2015 we were asked to have a look at a problem area in the highwall of Oceana Gold's Globe Prospect mine near Reefton.


To assess this we first undertook a detailed 3D survey of the mine with UAV techology generating an accurate model of the slope in question. Using OGL's rockfall register we were able to establish the frequency and mass of the rockfall occurences.


Using specialist software developed by Frans Basson to generate a modelled dataset we were able to establish the fallpaths of rocks of varying sizes. The dataset then provided us with the ability to alter the design width of a proposed lower bench to significantly reduce the number of fallpaths reaching the pit floor and haul road.


On a later visit to the site we were able to view a 2t boulder which had recently been arrested by this widened bench.


Jennian's Westport Show Home

January 31, 2015

In February 2015 we undertook a site investigation for Jennian Homes new franchise in Westport.


The sitework comprised some Dynamic Cone Penetrometer Tests and a couple of excavated trial pits.


It has been great to watch the show home develop over the past months and we are looking forward to attending the opening in the coming weeks!

Sealing a Tunnel

September 30, 2015

As part of the long term closure plan for Oceana Gold's Reefton mine we were tasked with a review of strategy for sealing a historical underground tunnel which forms a conduit for mine water to get into a nearby watercourse.


Using data provided by the client we were anle to generate a model and examine it using finite element methods to predict the groundwater flows through the rockmass. When the mine is rehabilitated it is planned to form a lake and therefore the mouth of the existing tunnel requires some sealing. We examined a sheeting solution and options for grouting.

Geotechnical Assessment of Agricultural Site Suitability

February 28, 2014

In early 2014 we were engaged to undertake geotechnical site investigations on proposed tank sites for Tasman Tanks across the West Coast, Canterbury, Tasman and Marlborough Regions.


There have been a number of sites which required some geotechnical design and ground improvement prior to the construction of these dairy effluent tanks.


Usually a site visit with Dynamic Cone Penetrometer testing provides sufficient information for construction recommendations where the ground conditions do not comply with NZS3604 definition of "Good Ground". The follow up normally has required the production of a PS4 (Producer Statement) to confirm that the proposed site preparation work has been undertaken to the specified standard.


We have developed a set of fixed rates for these tasks which allows clear budgeting for the client and cost effective solutions.


Additionally we have acted as Agent for some clients, assisting in production of Consent Documentation.


Drone/UAV 3D Model

June 01, 2015

In the winter of 2015 Oceana Gold's Reefton mine was surveyed using UAV technology. This survey was an update to the previous day's flying in March 2015. We were fortunate with clear and still weather and thus able to get some really good controlled flight lines.


The resulting data was run in Pix4D software to generate a 3d model and ortho photos of the mine. The accuracy of the model was impressive with 3D resolution to 50mm and a pixel resolution of 30mm on the orthos.

Highwall Mapping

September 30, 2014

In the spring of 2015 we were asked to spend a week on the highwall of Cascade mine owned by Buller Coal. The fieldwork comprised a series of mapped traverses along 3 benches of the highwall. Recording lithology and structural changes into a database and formatted for use with analytical software.

Tricky Nelson Sites

August 05, 2014

Since mid 2014 we have undertaken a number of small projects for Stonewood Homes' Nelson franchise. Often its a quick appraisal of existing data or in some cases more involved fieldwork and reporting.


It was gratifying to see a really well constructed retaining wall on a site in Hira which presented a number of technical issues.

Final Landform At Westport Quarry

May 31, 2015

Mid way through 2015 saw Black Lion Limited submit a final landform assessment of Holcim New Zealand's Westport Quarry.


Initially using historical data from exploration drillholes and reports it was found that an update of the geotechnical database was required. In August 2015 along with Alton Drilling and Opus Laboratories we drilled a number of holes in the eastern part of the quarry. For additional structural information Weatherfords Geophysics undertook some drillhole scans with their Acoustic Scanner to give us detailed in-situ structural information.


In October 2015 we were able to submit a far more detailed assessment along with wall stability, kinematic analysis and rock mass model.


The final landform and rehabilitation of the quarry into a landscaped lake and park will be a really good addition to the recreational assets of the Buller District and we are looking forward to seeing its development.

Geotechnical Assessment and Development of PHMP

February 09, 2014

In 2014 we were engaged by New Talisman Gold Mine in the Coromandel to undertake a geotechnical assessment and join the consulting team in development of the hazard management system.


The project involved a few days on site and underground assessing the existing support system and geotechnical features. From this we were able to undertake a preliminary Geotechnical Assessment, generate a geotechnical hazard map and take this forward into the risk assessment phase.


The outcome from this was the generation of a Strata Control Principal Hazard Management Plan to accompany the suite of documentation required by WorksafeNZ High Hazard Unit.

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Recent Projects


Here are some of the projects we have been involved in over the past 2 years, they range from foundation investigation to geotechnical mapping of extractive sites. Some of the work has involved the development of bespoke methods of analysis customised to the client's requirements.


Please check back here every now and then to see what we might be able to do for you! If there's something we may be able to help you with please feel free to contact us.