Equipment or method for borehole

Question

I am working at a construction site and came accross this issue. a borehole needs to be expanded in length inside a container-office. Working space is as little as 6m x 3m (19ft by 9.5ft). Height of the container is about 2m (6'6"). Heigt can somehow be altered up to 5 meters (16'5"). Borehole diameter is 150mm (6"). Current depth of the borehole is 30 m (98 ft). The depth should be increased to 42m (138 ft). See the attached sketch for details.

The borehole was bored before the containers were placed. It is used to measure water levels with piezometric sensors inside them. Water levels have dropped lower than expected and the borehole needs to be expanded in depth to reach lower groundwater deposits. Containers cannot be moved, and the location cannot be changed since this specific borehole is in a sensitive location, so please do not offer boring a new borehole outside the container.

What method or which equipment can be used to work in a small container space and can reach such depth.

Answer 1

I would recommend you consider a low profile diamond drill rig; something similar to the Sandvik DE140 (I'm not advertising).

Such rigs would definitely be able to drill the length of hole you require. Your space restrictions are the complicating factor.

Given you space restrictions, I also recommend you consider the underground drill rig version, as opposed to the surface drill rig version, as equipment designed to operate underground tends to be smaller than equipment designed to operate on the surface.

You will most likely have to raise the ceiling of the container where the hole is to be extended.

The diagram of the rig on page 7 shows it be 4250 mm tall when drilling vertical holes. It is advisable you have about 1 metre clearance above the rig, when it is operating; the more clearance, the better. For such a rig you will need to raise the ceiling of the container to the 5 metres mentioned in your question.

Depending on the type of access and the dimensions of the access available into the container, where the hole is located, it may be possible to used a vehicle mounted rig similar to the one in the first picture on this site. However, re-positioning the drill directly over the hole every time the rig has to be moved to add more drill steels, as the hole gets longer, will be a problem.

For more expert advice, contact an underground mining drilling contractor who has low profile drilling rigs.