MINE SHAFTS

Abandoned mine shafts pose a significant risk to both people and property.

Treatment of Mine Shafts

It is current practice to pressure grout the contents of abandoned mine shafts.

With a drilling rig erected on a suitable safety platform, the shaft is drilled to its full depth or to any desired intermediate depth. Then a PFA and cement grout is injected; when a suitable pressure is achieved the rods are withdrawn in stages and further quantities of grout injected until the shaft contents are grouted to the surface. Usually several treatment boreholes are required.

Occasionally an empty shaft requires treatment. In this case Groundshire will carefully fill it with
granular material, which may be grouted simultaneously.

Once treated Groundshire will, if required, form a suitable reinforced concrete cap at or near rock
head.

What are mine entries?

All mines needed a means of access, these were normally walk in ‘audits’ from the surface or vertical
shafts.

Mine audits are treated in much the same way as shallow mine workings and please see Mine
Workings Remediation PAGE for details.

Abandoned mine shafts pose a significant risk to both people and property.

Mine Shafts

Historically most old mine shafts were loosely filled with colliery debris or other loose material which
when wet can flow out of the shaft into associated workings at the base of the shaft.

This outflow may cause a collapse of the shaft walls and allow a crater to develop at the surface, the area of which depends upon the thickness of superficial deposits.

What is the outcome?

The outcome is that the ground we have worked on is safe and stable and is suitable to build on.
Although it is best practice to avoid building over treated mine shafts where possible. We future
proof your land.