Ground Support & Shotcrete Specialists
​civil    residential   tunnelling   mining​

A local Brisbane resident needed to stablise the eroding ground underneath her house.The dirt was taken out and cleared back to competent ground with the second stage adding drainage and mesh.  The sloping area was then shotcreted with a gun shotcrete finish.  The client was very happy with the rectification of this unused space.

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Jemna was engaged to provide a solution for Premium Pools and gardens of Sumner Park  to an undermined pool surround in a back yard in Kenmore. Not only was the pool slab undermined but it was unsightly for the neighbouring yard.

With the use of coloured shotcrete Jemna operators infilled the underside of the pool slab and filled out the wall. The Neighbour was insistent the bougainvillea plant was to remain, so Jemna will be returning to dyna bolt some runners on the wall so they can get the plants to creep over time and cover the wall with greenery, a courtesy that jemna will provide to enhance the job and please the customer and the client “Premium Pools and Gardens”.

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December / Jan 2016 Jemna was contracted to B.M.D Constructions to prepare and shotcrete a preconstruction hit and miss wall on the Bruce Highway Gympie. The project took 3-4 weeks to complete the 350 metre wall. The initial preparation also carried out by Jemna involved the installation of stabilized sand to the 1 in 1.3 batter to the TMR spec. prior to the shotcrete application. To finish the wall Jemna concreted a footpath at the top of the wall at a 20% fall back.This again was a logistic challenge on the batter Height and design coupled with the extreme heat both from the weather and the reflection of the concrete in the corridor that measured at times up to 53 degrees.

Grace Chemicals Australia used Jemna’s shotcreting services to trial their shotcrete admixtures and Hanson mixes at the Wolfdeen Quarry, Beenleigh. The West Connex representative from B1 and B2 in Sydney were present and noted predominantly the reduction in rebound achieved with the finer mix designs.  The Road Runner road registered shotcrete rig was used due to the steep quarry wall that stood approx. 15 metre in height to the highest point. This Shotcrete Rig eleviates height aids, stand-alone compressor and allows the shotcrete to be sprayed using minimal labour.

Hanson Concrete own the Wolfdeen Quarry at Beenleigh, Queensland which is where they pull their blue stone for their concrete mix.  After allowing Grace Australia to use their quarry for a shotcrete trial which was sprayed by Jemna, Jemna Director Ben Ferri was asked to return and manage more shotcrete spraying to complete the quarry wall that will later stand above the new four weigh bridges being installed as part of the quarry expansion that is expected to have a further 200 year mine life.

Australian Tunnelling Society (ATS) asked Jemna to demonstrate the shotcrete component of tunnelling construction at their Tunnelling workshop in October 2015. Jemnas’ Shotcrete Road Registered rig was used to show the ease of use when shotcreting high walls at the Brisbane City Council Toowong Quarry. Other demonstrations included the fire and smoke testing used in the Legacy Way tunnel project, soil anchor installation and Hilti demonstration.ience's attention...

Initially Jemna was called upon to carry out remediation works on the 6 metre excavation that due to ground conditions and excessive rain prior to the piles being installed was rapidly deteriorating posing threat to the properties above.  After carrying out this operation Jemna remained to install steel, shotcrete and drainage for the Pile wall surrounding the basement and to respray over the previous contractors work giving a total flat gun finish wall. These works were carried out successfully and timely and the client was happy with the gun finish product. Access for these works was logistically challenging with the distance and tight street frontage.

Sydney tunnels are on their way.  With numerous tunnels in design and construction under the large and increasingly congested city of Sydney, Jemna were commissioned to carry out the Shotcrete Preconstruction mix design trials for the NorthConnex Tunnel.  The NorthConnex Tunnel will link the M1 Pacific Motorway at Wahroonga to the Hills M2 Motorway at West Pennant Hills, for more inform click on motorway linking the M1 Pacific Motorway at Wahroonga to the Hills M2 Motorway at West Pennant Hills – called NorthConnex.

These product trials double as a trial of the equipment proposed for the tunnel shotcrete provided by Normet shotcrete machine manufacturers. Jemna worked in with K&H Geotechnical services whom tested all the samples. Early strength testing, UCS, Flexural RDP’s and EFNARC beams, this testing was carried out vertical and overhead to simulate a tunnel environment.

A local artist employed Jemna services to provide a solution to vertical batter wall behind her house. The works were carried out under the owner’s direction. Jemna created planter boxes in the wall and the artistic owner of the property followed our crew drawing into the workable state of shotcrete. The owner also requested that the bikes and scooters from her now grown children be sprayed into the wall adding a further unique effect.

The wall was not coloured as the owner has plans to create mould on the wall in the coming month’s boasting a more natural finish. The product applied was using the EPC Barchip poly fibre as reinforcement as opposed to steel mesh a technology commonly used in the construction of tunnels and mines all over the world.

Brookfield State School employed Jemna services to provide a solution to the unsightly and loose nature of ground on a sloped batter between their netball courts and the tennis courts that are used by both the school and the local community members.

Jemna provided and applied a coloured solution gun finish wall that has improved the aesthetics of this area and blends quite well to the landscape and pristine nature of the flora surrounding the area. Jemna also provided concreting services to extend the concrete slab for future expansion of the public viewing area.

What people don't know! The Legacy Way Tunnel transporting commuters from Toowong to Kelvin Grove actually contains numerous tunnels that the public will never see. In between the two road tunnels made by the TBM, there are 25 small cross cut tunnels. Jemna has been involved in each of these small tunnels which are used for service personnel and maintenance.

The Legacy Way Tunnel, Toowong Portal project started in 2011 with the first smaller conveyor  tunnel being made from the Toowong Portal to the quarry past Mount Cootha.  This conveyor  tunnel was built to enable conveyor belts to carry the excavated spoil  from the TBM without  having to use our roads, alleviating the pollution (air and noise) that is usually  from trucks carrying dirt  in surrounding surburs of the Portal while construction is taking place.

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Jemna Pty Ltd has carried out all pre-construction Concrete Mix Trials for the Conveyor  tunnel as well as the Legacy Way Road tunnel to ensure that the right proportion of mix used will guarantee the longevity that these underground tunnels  require.

Jemna was also asked to shotcrete Water Detention tanks on the side of the Centenary Highway via its Road Registered Robotic Shotcrete truck.

The T2E runs for 16.3klm consisting of Highway road and 360 metres of tunnel with the entrance being at Ewingsdale.  The job is moving 3.5million tonnes of dirt and is a highly environmentally sensitive worksite.

Jemna started its involvement with this project carrying out the preconstruction mix trials.  Jemna was then awarded the contract for 40 kilometres of shotcrete handsprayed concrete storm water drain linings.  The speed and success of the project has given Jemna the opportunity to upgrade from their one crew contract to using a three man x three crew.

When the project reached the tunnel stage, the entrance being at the Ewingsdale end , Baulderstone  requested Jemna’s service for their Tunneling needs.  The tunnel project required training and certification (VOC), Vehicle operational Competency for Baulderstones shotcrete operators and underground Robotic Shotcrete equipment.

The Pacific Highway upgrade is coming to a close, it started in 2012 and will finish 2016.  This contract is a special contract for Jemna, being the first major civil job under its belt.