Underground » Ventilation, Gas Drainage and Monitoring
This project is a continuation of ACARP project C17017 "Phase I - Coiled Tube Drilling System Development - Risk Mitigation". The Phase I project developed a concept and performance specification for an underground in-seam coiled tube drilling rig. It also addressed a range of technical risks including a rigorous experimental program to quantify low cycle fatigue limits of the tube, and resolved issues associated with the geometric constraints of an underground coiled tubing rig. Upon review, the technical committee favoured a more conventional approach to rig design, which is only enabled by incorporating steering capability in to the borehole assembly.
The primary objective of this project was to complete a comprehensive industry survey of gas drainage practises in order to develop the functional specifications for an advanced underground in seam gas drainage drilling rig. Additional project objectives focused on investigating down-hole technologies required to support the proposed rig. These include:
· Down-hole steering capability;
· Bi-directional hi-bandwidth wireless communications; and
· Improved borehole survey accuracy.
Seven UG coal mines from Queensland and New South Wales participated in the survey. In addition, several commercially available down-hole indexing/orienter devices have been identified that enable a down hole steerable borehole assembly. Further development work is now underway to fabricate and test a new borehole wireless communications system. The major project recommendation is to undertake further development of the conventional rig concept. Further, an experimental program should be setup to test the BHA orienter sub (using existing UIS drilling systems or compact civil coiled tubing rigs) and confirm predictions of improved low cycle tube fatigue.
Both the Phase I and Phase II reports are provided together.