HDD operations should only be performed by trained and experienced contractors. Nonetheless, such operations may encounter various difficulties, including:
- Loss of drilling fluid or loss of circulation (flow)
- Obstructions (cobbles, debris, foundations, ...)
- Line and Grade Problems
- Bore hole collapse
- Failure of drill rods or downhole tooling
- Surface collapse or heaving
- Inadvertent drilling fluid returns (surface, waterways, ...)
- Striking or damaging existing utility
- Product pipe failure or damage
- Product pipe stuck in bore hole.
Prevention practices for contingency plans and methods for mitigating such problems are available in industry guidelines; e.g., Horizontal Directional Drilling -- Good Practices Guidelines (3rd Edition, 2008, HDD Consortium) and Guideline - Planning Horizontal Directional Drilling for Pipeline Construction (Canadian Association of Petroleum Producers, CAPP Publication 2004-0022, September 2004).
Following installation of the pipe, it is necessary to confirm the viability of the new facility, as well as to provide a permanent record of the actual placement location. The following steps should be performed:
- Pipe Testing
- Site Cleanup
- Certified Record ("As-Built") Drawings
ASTM International F1962 (Standard Guide for Use of Maxi-Horizontal Directional Drilling for Placement of Polyethylene Pipe or Conduit Under Obstacles, Including River Crossings) and PPI TR-46, (Guidelines for Use of Mini-Horizontal Directional Drilling for Placement of High Density Polyethylene Pipe) provide appropriate practices at the completion of the pipe installation.