Current Projects    - projects completed less than 5 years ago

Geotech Ltd were engaged by a private landowner to provide rock bolting services for a retaining wall. Design was provided by Andrei Cotiga (Eliot Sinclair). A full grout testing panel was undertaken to ensure the design standard was met.

Following curing time, pull testing was undertaken by Andrei and the Geotech team. Bolts were tested to 80% of the Design Test Load (70kN), which was easily achieved.

The Eliot Sinclair team were clear in both design and quality assurance plans, meaning the project ran smoothly and on time.

Queenstown Trails Trust (QTT) engaged Geotech Ltd to refurbish the existing 108 metre long Shotover Tunnel, part of an 18-kilometre cycle trail. This tunnel was originally constructed in 1962, using drill and blast methods and with future opening to public usage there was a need to ensure no fretting or rockfall exposing the public to risk.

Geotech were tasked with removal of some 45m3 of fretted and fallen material from the tunnel and removal of some 45m3 of rock to ensure the 2x2 metre tunnel was fully maintained. This volume removed included localized protruding rocks from both of tunnel rib and roof using a combination of localized smoothwall type blasting and mechanical rock breaking. The tunnel also had two areas with localized geologically structural defects requiring rock bolting and meshing.

Manawa Energy engaged Geotech Ltd to refurbish the existing 440 metre McKay’s Tunnel, part of the Kaneire Forks Hydroelectric System. This tunnel was originally driven in the 1880’s, through fluvioglacial gravels for the purpose of powering nearby gold dredges. A 2021 inspection revealed a 12-metre fall of ground (FOG) within the tunnel, as well as other areas of failing tunnel lining.

Geotech were tasked with removal of FOG material, and stabilsation of tunnel lining. Stabilisation works included installation of new timber lining and props, using a steel “ranter” set for overhead protection allowing further progress through areas of instability. Along with the ranter sets, spiling was also employed as a temporary means of overhead protection during advance and installation of timber lining. Similarly, a cellular concrete crash deck was used in roof voids to further safety during works.

Geotech Ltd were engaged by Geostabilization International (GSI) to remediate a failed shotcrete stabilisation job on the Karamea Highway. Works involved hand- spraying shotcrete over the highway bluff from a hiab-mounted mancage, as well as clean up from previous failed shotcrete.

Due to previous failures on the same works area, there was the need for a high-end quality assurance spread. This included supply of aggregate certificates for all elements of the shotcrete mix, crush tests for cored and cast shotcrete samples, and detail on accelerant dosages and shotcrete thickness. Specifications for the work required the shotcrete crush tests to be above 30 MPa at 28 days, which our mix design accomplished with ease.

As a component of Meridian Energy’s ongoing asset management programme, consultant engineers WSP were engaged to evaluated the Manapouri access tunnel well being. Some sixty years has elapsed since construction, although some upgrading of ground support has been done over the intervening years, using shotcrete and rock bolting.

WSP designed an evaluation programme based on pull testing, over coring and localized bolt replacement.

Geotech Ltd, were awarded a physical works package and duly mobilized to Manapouri. Although very remote, Meridian Energy staff were extremely helpful and that significantly remediated the isolation difficulties.

Industry standard testing was conducted, all from an elevated mancage. Natural tunnel ventilation was sufficient ,but took some management as airflow and direction varies with climatic conditions and station power production. Shotcreting and drilling using diesel compressors and gensets was conducted when ventilation conditions were favorable.

In early 2023 Geotech Limited were awarded a contract to rebuild a failed portion of the Donkey Winch Wall situated high on the Denniston Plateau at the start/loading area of the famous Denniston coal transporting Incline. This site is extremely popular, often cold and bleak, difficult to work on and always rewarding.

The Department of Conservation manage the site under authority from Heritage New Zealand, who administer Class One historic sites such as this. Dominant legislation is the Heritage New Zealand Pouhere Taonga Act (2014). To operate and construct under this regime Geotech had to be cognizant of the following documentation required for the site:-
* Heritage NZ archaeological authority 2019
* Denniston Stonewalls Archaeological Management Plan 05062019 version 3
* Denniston Stonewalls Archaeological Assessment

In addition to the above, reconstruction was to comply with McManus Geotech “Denniston Design Report 2023”
Project Manager: Mark Nelson Senior Works Officer, DOC Hokitika cell: 027 304 3520
Project Engineer: Kevin McManus McManus Geotech Ltd cell: 0272017793
Project Archaeologist : Nick Cable WSP Christchurch cell: 027 705 8330
Stone Mason : GT Stone Gary Swanson cell: 021 024 13052

Geotech were engaged by the North Canterbury Transport Infrastructure Recovery(NCTIR)to assist with restoring road access to Kaikoura after the 7.8 magnitude earthquake in November 2016. Geotech staff have been working on sections of the narrow coastal corridor of SH1 south of Kaikoura, with additional crews working north of Kaikoura. Works have predominantly been made up of clearing landslides. Work is not straightforward due to the fractured cliff faces being unstable. Damaged slopes continue to release rock and material, and weather events and continuing seismic activity have presented ongoing challenges throughout the contract, including additional land and mud slides during bad weather events.