Tunnel Guard, a Thin Sprayed Liner (Super Skin), was developed by South African Mining & Engineering Supplies in 1994. It is used as a support element to seal and consolidate various problematic rock types and prevent oxidation of the rock in standard and high-risk areas. Primary benefits of the product are its durability, ease and speed of application.
Thin Sprayed Liners (Super Skins) are widely used because they work often when no other means of support is available. In large part this is because they can be applied rapidly and safely, reinforcing the rock mass in the early stages before it moves too far down the ground reaction curve.
This mechanism is considered to be particularly relevant in very high stress situations in which some loosening will have taken place and in which on-going stress-induced fracturing does occur. Tunnel Guard penetrates into the rock mass along open fractures and joints and acts as a hard, rough gouge filling, increasing the cohesion across the fracture and the strength of the rock mass and limiting the ability of the rock fabric to move. (Key block-interlocking). Due to the good adhesion capability of Tunnel Guard it is an excellent sealant and support mechanism. This capability prevents weathering and deterioration of fractures and preserves your excavations for long term mining.
Tunnel Guard Sprayed on Savuka Gold Mine
The preparation of the rock substrate is very important, it is imperative to wash down the rock surface of all dust and it is also necessary to bar down any larger loose rocks to improve application safety. When the surface cannot be washed down the dust needs to be blown off using compressed air to ensure maximum bonding. Through the correct preparation of the host rock, up to 200m² can be applied in one shift, which makes Tunnel Guard the ideal support solution for high speed development ends. Because the application of Tunnel Guard is between 3mm and 5mm, smaller material quantities are required for the application thickness. Due to the thinner application requirement, Tunnel Guard is a more cost effective alternative to Shotcrete or Wetcrete and can be transported and applied considerably faster. Tunnel Guard should always be stored in a cool and dry environment.