Vent Walls

Concrete Cloth™ is being used extensively on large-scale mining projects

Concrete Cloth™ (CC) Geosynthetic Composite Cementitious Mat a fast alternative for constructing permanent or temporary blast and vent structures. The product is prefabricated and easily transported and stored underground. It can be fixed to the rock face using standard power tools and comes in a man-portable roll form, alleviating logistical difficulties associated with traditional methods. CC is uniquely suited for installations in remote, difficult to access sites where logistical efficiency is key. CC is well suited to use in extreme environments and has been used installed in environments with sub-zero temperatures such as Northern BC in Canada and at 4000m altitude in the Chilean Andes.

Vent Wall

Below are direct cost comparisons between two popular and widely used vent closure methods in underground mining and Concrete Cloth:

Steel Stoppings
Pre-fabricated, 1’ steel panels that are actually 2 panels telescoping within each other to run from floor to ceiling. Connected with clips and angle iron supports, every 3’. Constructed from the center of the opening to outboard walls, sealed with foam packs.

Panel cost (143.72’ x 15’)    CAN $2155.80
Angle iron supports (6 x 12.06’)    CAN $72.36
Foam pack    CAN $200.00
Labour (2 men, 12 hour shift)    CAN $887.32

Total per vent wall = CAN $3315.48

Sprayed concrete over a lined, 3” meshed panel.

Backer panels    CAN $646.87
Supplies and equipment    CAN $200.00
Shotcrete material    CAN $657.00
Labour (1 skilled, 2 unskilled)    $1364.30

Total per vent wall = CAN $2868.17

Concrete Cloth
Prefabricated, cement-impregnated fabric that becomes a hard, durable, fire-resistant and waterproof layer once hydrated with water.

CC5 (Batched rolls, 21m2)    CAN $1379.07
Framing supplies    CAN $150.00
Foam    CAN $28.21
Labour (2 men, 12 hour shift)    CAN $887.32

Total per vent wall = CAN $2445.00

% saving over Steel Stoppings = up to 25%
% saving over Shotcrete = up to 15%

Vent Wall

Nuna Innovations Inc. were commissioned by mine owners Vale Canada Ltd, to supply Concrete Concrete Cloth™ (CC) GCCM* and relevant installation advice on erecting vent seals at Creighton Mine, an underground nickel mine in Ontario, Canada. The use of CC has changed the way vent walls are now constructed within the mine. Traditionally shotcrete would have been used, which not only requires multiple crews for installation but also planning and considerable expense. The speed of installation on the project reduced planned closure times, which in turn resulted in financial and time savings. The use of CC inremote areas meant that fewer workers were involved in moving equipment, supplies and machinery, allowing savings.

Vent Wall

In May 2014, Concrete Concrete Cloth™ (CC) GCCM* was used to create a vent wall at The Super Pit mine in Kalgoorlie, Goldfields W.A., Australia. The was KCGM (Kalgoorlie Consolidated Gold Mines) and was a joint venture between Barrick and Newmont. It was identified that ventilation needed to be improved in the lower levels of Mt. Charlotte Underground Mine. As the area was difficult to access the use of conventional wall construction methods such as shotcrete were not an option. The vent wall was installed by 3 people in 3 days. The project was deemed a success and it is likely that Concrete Canvas will be used for further vent walls within the mine.

Ditch Lining

Concrete Concrete Cloth™ (CC) GCCM* was specified in the construction of vent walls at Marblaegis Mine, an underground gypsum mine in Loughborough, UK. British Gypsum, was having problems building vent walls. Using concrete blocks was a slow and expensive, requiring specialist labor. Brattice cloth was used as a temporary measure but lacked durability, and their self-produced gypsum boards were prone to rotting. They were looking for a durable, flexible, cost-effective alternative. British Gypsum was very impressed with the result, stating that CC was installed as quickly as gypsum board but without the rotting issues. They also noted that CC is far more durable than brattice cloth and cheaper and easier to move and install than concrete block walls.

For more information on vent wall and other mining applications, view our Mining PDF:

*Geosynthetic Composite Cementitious Mat

Concrete Cloth Characteristics

Concrete Cloth is a flexible cement impregnated fabric that hardens on hydration to form a thin, durable water proof and fire proof concrete layer.

Essentially, it's concrete on a roll Just Add Water.

Easy To Use

Concrete Cloth is available in man portable rolls for applications with limited access or where heavy plant equipment is not available.

There is no need for mixing or measuring, the concrete is premixed and cannot be over hydrated. It will set in fresh and sea water.


Once hydrated, Concrete Cloth remains workable for 2 hours and hardens to 80% strength within 24 hours.

Accelerated or retarded formulations can be produced to meet specific customer requirements.


Concrete Cloth has good drape characteristics, allowing it to take up the shape of complex surfaces including those with a double curvature. Unset Concrete Cloth can be cut or tailored using basic hand tools.

Hydrocarbon Resistance

CC offers hydrocarbon resistance to BS:14414; based on a 56 day immersion test at 50°C


The fibre reinforcement prevents cracking, absorbs energy from impacts and provides a stable failure mode.


Concrete Cloth is chemically resistant, has good weathering performance and will not degrade in UV.

Water Proof

The PVC backing on one surface ensures that the material is completely water proof and chemically resistant.

Fire Proof

Concrete Cloth is a ceramic and will not burn.

CO2 Savings

Concrete Cloth is the only way of laying a thin concrete layer from a prefabricated roll of material.

This enables up to 150 mm of poured concrete to be replaced with just 8 mm for many surfacing applications.

As a result, material savings of 95% can be achieved for a typical construction project.

This directly reduces the CO2 footprint of construction work not only through material savings but also through reduced road transport and time on-site.

Low Wash Out

Concrete Cloth traps dry concrete powder in a 3-dimensional fibre matrix. Testing based on BS8443 to indicate the effect of underwater setting, shows that Concrete Cloth loses only 3% by mass.

By comparison, specialized underwater concretes typically lose between 10-15% while also requiring much larger volumes to be poured.


Concrete Cloth uses a specialized high early strength concrete with a limited alkaline reserve. Unlike most concretes, it is not classified as an irritant and is less damaging to the environment.

Environment Agency Approval (UK)

Concrete Cloth was approved for use by the Environment Agency (EA) Biodiversity team in 2010 for the Church Village Bypass Project.

Benefits cited included ‘surface roughness to provide diversity in the channel's morphology’ and its ability to introduce ‘sinuosity in the channel line’.

Several projects have since been granted approval on a case-by-case basis and the EA recently purchased Concrete Cloth directly for internal use as a weed inhibitor.


Untreated Concrete Cloth will naturally ‘green’ over time as the textured top surface allows moss growth, whilst the fibre-reinforced concrete layer will prevent root-growing vegetation, which would otherwise restrict water flow and increase maintenance costs.

Nuna Innovations Inc.

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