Unrolling of a metallic mesh inside small mine tunnels

Prize: 14,000 USD

Status: completed


Ingeniería y Construcciones Mas Errázuriz is a company specialized in the execution of mining, energy, and medium-big size infrastructure works. It delivers a quality service with high safety standards and a strong commitment towards its employees.

It is known for its innovation, safety and sustainability commitment that helped them carry out big projects in Chile, Peru, Argentina, and Ecuador. 

The challenge:

The construction and reinforcement of tunnels in mining is a process with 3 activities:

•          Boring and protecting the tunnel with a layer of shotcrete.

•          Unrolling a metallic mesh and placing it on top of the shotcrete.

•          Securing the metallic mesh with helical steel bolts.

This challenge focuses on the unrolling and pre-installation of the metallic mesh. This activity is currently carried out with big-sized machinery (see  https://www.geobrugg.com/en/MESHA-installation-handler-7976,7859.html for more details)

However, it does not have enough space to work in tunnels smaller than 4m x 4m in mine-preparation projects by “Block or Panel Caving”. The challenge here is how to efficiently unroll and place on the wall the metallic mesh, either by adapting the machinery or using a different method.

The mesh for this challenge has a specific weight of 2.2-5.5 Kg/m2 and it is unrolled gradually sector by sector. Ideally, every sector has a depth of 3.5 to 4.5 m. The current unrolling process has an approximate productivity of 4.5m every 30 minutes and, for safety reasons, every sector overlaps with the previous one by 30 cm. (See  https://www.geobrugg.com/datei.php?src=portal/downloadcenter/dateien/downloadcenter/level1-data-sheets/MINAX/L1_MINAX-80-4mm_TechData_171102_2.5mx15m_e.pdf for more details about the mesh).

See Annex 1 for the pictures of this machinery (Boltec s/m Epiroc and Sandvik ds311), the metallic mesh, and the securing bolts.

Once the mesh is unrolled and placed on the wall of the tunnel, there must still be enough space (at least 3.8m between the mesh and the tunnel floor) so that the machine can install the bolts.

What the client is looking for:

The goal of this challenge is to find solutions to unroll the mesh and place it on the wall in the tunnel, before securing it with helical steel bolts. This activity must be carried out without workers since they cannot leave the area already secured.

The new solution does not have to use the current machinery, which will be used in the next stage.

Evaluation criteria:

1)    The maximum investment cost for every machine must be 20,000 USD.

2)    The maximum productivity is required.

3)    The simpler and more adaptable the new solution, the better. 

This 2-round challenge has the following deliverables:

Round 1:

A PDF document including:

•          Description of the proposed solution.

•          Estimated costs.

•          Graphic documentation: sketches, images…

Round 2:

A PDF document including:

•          Detailed specification of the solutions: plans, materials, etc.

•          Final clarifications.

Timeline: this is a 2-round challenge:

•          Round 1: 6 weeks + 2 weeks for evaluation.

•          Round 2: 4 weeks + 2 weeks for evaluation.

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