Directional boring

Next, the bore created during pilot hole drilling is enlarged to a diameter that will facilitate installation of the desired pipeline.

Lastly, the pipeline is pulled into the enlarged hole, thus creating a continuous segment of pipe underground exposed only at the two initial endpoints.

Directional boring can be utilized to cross any number of surface obstacles including roadways, railroads, wetlands, and water bodies of varying sizes/depths.

Problematic soil conditions include large grain content in the form of coarse gravel, cobbles, and boulders.

[4] The equipment used in directional boring depends on the length of the (proposed) crossing, the pipe properties (of the to-be-installed pipeline), and the (anticipated) subsurface conditions.

[5] Tooling, as in the mechanical apparatus that are installed to the drill string to conduct operations, are available in a wide number of different shapes and sizes.

Tooling intended to navigate rock, or tougher formations, may use tungsten carbide alloys or polycrystalline diamond (PCD).

In contrast, tooling intended to navigate soft soils may be limited to high carbon steel (milled to a desired shape and size).

Within rock formations, hydraulic excavation is still taking place to some degree (evacuating spoil) but the lion's share of cutting and breaking up material is due to mechanical work being done by the tool itself.

It is used instead of other techniques to provide less traffic disruption, lower cost, deeper and/or longer installation, no access pit, shorter completion times, directional capabilities, and environmental safety.

Since uncontrolled drilling can lead to damage, different agencies/government authorities owning the urban right-of-way or the utilities have rules for safe work execution.