Please use the glossary below to check the meaning of any of the language or terminology used in your mining report. If your question is not answered here please check our ‘Frequently Asked Questions’ Section.

If you require any further clarification of the meaning of your mining report or the terminology used within it please contact us and CoalSearchPlus+ staff will be pleased to help wherever possible.

What is a shaft ?

A shaft is a vertical or near vertical mine opening used for access, removal of minerals or ventilation of a mine.

What is an adit?

An adit is a passage for access or drainage, driven at a shallow angle (usually below the horizontal), often in a hillside. An adit may also be referred to as a drift.

What is a tip or lagoon?

A tip is an area of surface ground where waste from coal mining activity has been deposited. This is often in the form of a large mound and will consist of coal that has been deemed to be unsaleable and or other materials removed during the course of mining activity. Tips will now often have been landscaped and fully remediated in order to make them stable and aesthetically unobtrusive.

A lagoon is a pool or small lake that was often situated at the top of a tip. Mine water was then pumped into the lagoon and gradually filtered down through the tip deposits emerging from the bottom cleaner and safer.

What does partial extraction mean?

Partial extraction means that even though a seam of coal has been worked not all the coal in that seam has been removed. It is possible that pillars of coal or other rock have been purposely left in position as further mining has progressed in order to support the roof of the tunnel during coal extraction and after mine abandonment.

What does adjacent workings mean?

Adjacent workings are coal workings that are within the zone of influence for a property but not directly underneath the property. These workings are within a distance equal to 70% of the depth of the workings, taking into account the inclination of the seams, from the property or its boundary.

What does subjacent workings mean?

Subjacent workings are those that lie directly below all or part of the property and its associated land.

What is an opencast site?

An opencast site is an area where coal has been removed by first removing the layers of  rock and deposits immediately above it so exposing the coal at the ground surface. The coal is then removed directly without the need for underground workings.  This style of mining is only carried out in the UK where the coal deposits are relatively shallow.

Opencast sites are often associated with large waste tips. Once opencast sites cease to be worked they are often landscaped and fully remediated.

What is subsidence?

1. Subsidence is downward movement of the ground as a result of processes independent of applied the load.
2. Subsidence can be movement of the ground caused by loss of support over mine workings. It is a three-dimensional phenomenon involving rotations and translations within the ground, and often gives rise to differential vertical movement and horizontal strains of the ground surface.

The movement of the ground in either of these circumstances could lead to damage to property or land.

What is a fault?

A fault is a fracture or fracture zone in the rock strata along which there has been displacement of one area of ground in relation to an adjoining area. This is an area where future relative movement of ground may recur and give rise to subsidence or ground instability.