Published in the December 2005 American Longwall Magazine

While seal integrity is one issue, management is also faced with the bottom-line pressure associated with the cost of transporting blocks (used in traditional block seals) to remote areas.

With these challenges in mind, underground chemicals specialist Minova has come up with several products to counter issues surrounding seal integrity and transportation and installation costs.

Minova’s answer to traditional block seal limitations is Tekseal – a specially formulated pumpable grout.

Before installing Tekseal, two walls spaced at least 1.2m apart are formed. Each wall consists of 12cm square posts evenly spaced across the opening and two planks nailed across the posts.

Brattice cloth is then nailed to the form work and overlapped at the edges and the Tekseal pumped in via a placer unit.

Minova has also taken it into account that cementitious grouts are not always suitable and offers the Carbofill range for this market. Carbofill comprises a two-component phenolic resin-based foam, which according to Minova has a rapid reaction time, high foaming factor and is non flammable.

The resin foam is generated via a Minova-supplied pump which can be cleaned easily with water.

The company said the advantage of these products was that a minimum amount of material had to be transported to the seal site.

The application of the seal was quick because of the rapid reaction time and high expansion of Carbofill.

Carbofill can also be used for foam support in roof cavities on longwalls or roadways and for sealing roof cavities against methane build up.

Minimal transport means the product can be ideal for situations where a seal or stopping needs to be installed quickly to control ventilation problems such as a heating in the goaf.