A Trial Pit is a hand dug excavation of up to 2 metres in depth. It is used to assess ground conditions near the surface which in this case gives an indication of whether the area being investigated is above a mined area or is made of back filled quarry material.

A Borehole cuts a “core” of soil and rock below the ground surface. This gives an indication of whether an area is undermined or not. If mined, it gives an indication of the depth and structure of the mine below. The depth of these boreholes will be up to 20 metres, with a diameter in the order of 150mm (6 inches).

The machine used to make boreholes is a Drill Rig, an example of which is shown in the photograph overleaf.

The Trial Pit and Borehole locations will be based on the results of both a geophysical survey and the findings of underground surveys. When borehole locations are finalised property owners will be kept fully informed by the engineer in charge during the works.

Boreholes may also be required to check that the level of materials used to stabilise the mine have reached the required level.

The engineer will arrange to meet with residents at properties where Trial Pits or Boreholes are required to explain the need for the works. The risk analysis undertaken to justify the need for Boreholes will be made available on request.

If a borehole is required in your property a garden survey and photographs will be taken, to help ensure that the garden is restored to its former condition.

Boreholes will be drilled using one rig at a rate of approximately one borehole per day. This work will be followed by infi lling with gravel which will take an additional day.

On satisfactory completion of the investigation works full reinstatement of the garden or highway will take place. The engineer and contractor will endeavour to complete the works as soon as possible.

Working hours will be 08:00 - 17:00 weekdays. It is unlikely that Saturday working will be required but the engineer will keep you informed of progress.

Depending on the location of the trail pits and boreholes, a single lane road closure may be required operated by traffic lights. The traffic light system will be manually operated during peak traffic, and pedestrian access to your property will be maintained.

The contractor will ensure that noise and dust from the operations will be kept to a minimum.