Drilling Down: Case Study – London

In this edition of ‘Drilling Down’ , we take a look at how Minnovare added significant value to Europe’s largest railway and underground infrastructure project at the time.

Location: London, United Kingdom
Industry: Civil Construction – Tunneling
Specialisation: Compensation Grouting, Foundation Works
Year: 2013

Minnovare’s The London Crossrail is Europe’s largest railway and underground infrastructure construction project, with works currently under way in central London.

As part of the tunnelling program, prime contractor BBMV were engaged to conduct an extensive compensation grouting program to support the structural integrity of London city structures above the underground works.

Issues on Site:

The compensation grouting program required thousands of holes to be drilled to a precision of 0.1 degrees. The drilling was being conducted amongst underground workings, sewer lines and directly under major London city structures.

Drill hole accuracy was of paramount importance to ensure unplanned and potentially catastrophic intersections did not occur. Land surveying methods used to set the drill rigs up to the required accuracy were time consuming and expensive. The process required the surveyor to take laser readings at the front and back of the underground drill rig and calculate the adjustment angle required.

Using this information the driller then manoeuvred the drill rig to the approximate adjustment angle. The surveyor would conduct another laser reading to confirm alignment. This process would involve multiple check surveys, recalculation and drill adjustments until finally aligned to the design azimuth and dip. The surveyed alignment was also used as a starting reference for a nonmagnetic (MEMS) survey instrument used to measure the drill hole trajectory after drilling.

The Solution:

Minnovare’s Azimuth Aligner (AA) is the most accurate drill alignment technology in the world (+/-0.2°).

In every situation the AA performed better than expected – providing highly accurate down-hole alignments, despite the highly challenging conditions. Initial drill rig setups were completed in just five minutes, with no assistance required from surveyors – all thanks to the Azimuth Aligner.

The Result:

The results achieved through the implementation of the AA reduced downtime hours associated with setup by 160 hours per rig per year, resulting in improved underground drilling productivity for their client. As a result of the increased time available for drilling, the contractor was able drill an additional 790 meters per rig per year. The client experienced further direct savings through the reduction in labour and associated costs.

For more information on this case study and/or the Azimuth Aligner, contact Minnovare on +61 8 6381 0076 or info@minnovare.com