Richard Fielden, Director of the British Drilling Association describes what the Association’s audit entails

All sectors within which the drilling industry works have their own unique requirements, but it is perhaps the rail sector more than any other that presents the most challenges. In fact, railway infrastructure poses a wide variety of unique environments in which to undertake ground investigations, many of which requiring innovative thinking combined with adapted rigs, plant, and equipment. Of course, risk is present on all rail projects, just like any other sector, but with so many other factors present, it is risk, or more specifically its minimisation that has to be engineered and educated out.

Managing risk is a multi-faceted task but having British Drilling Association (BDA) trained and accredited staff on site is ultimately ‘one less thing’ to worry about during the delivery of what are extensively and meticulously planned projects.

The complexity of rail infrastructure projects means what may be considered a minor inconvenience during a standard ground investigation could ultimately mean the shift or in some case the whole project being postponed. It is these pinch-points during rail infrastructure projects that often require unique approaches, developed collaboratively with all parties involved and therefore rail project managers need to be confident that the proposals and solutions offered from the driller’s side are based on a proven knowledge. Such solutions must always fall within often legislated standards and methodologies, and of course, the BDA Audit is proof of such adherence.

In fact, the single most important and effective proof of competence of the drilling team on any rail infrastructure project is the BDA Audit. It is proof the drilling company is not only committed to improving efficiency, health and safety and standards, but will demonstrate these through the work they undertake on site. And the BDA Audit has evolved considerably in recent years and now carries that all-important third-party accreditation through the Minerals Product Qualification Council (MPQC) and brings the BDA Audit fully in line with BS22475-2&3.

The BDA Audit is also in line with Network Rail’s own desire for better quality ground investigation data as well as being echoed in its drive for safe working practices, high standards of workmanship, and compliant and certified equipment. Of course, the BDA Audit fully supports, and quality assures this aspiration and proves compliance with machine safety standards and regulations, recognises the skill and achievement of drilling staff, and allows companies to fully comply with the documented expectations of the recently re-published Thomas Telford, UK Specification for Ground Investigation.

BDA member Geotechnical Engineering is a good example of the benefits of having BDA Audited drillers, having worked with Network Rail over many years. In fact, its slope climbing dynamic sampling and rotary drilling machines were designed and manufactured to enable better quality ground information to be obtained from embankments and cuttings, right across the rail network and to meet the complex demand of typical rail infrastructure environments. Often, investigations were historically frustrated by the excessive costs and complex logistics of working in remote sites and the need and expense of scaff old platforms for conventional plant, crane lifts for access etc., and the alternative lightweight, handheld, or small, tracked equipment, also had significant limitations from borehole depth, access difficulties, and data quality perspectives. Shallow refusals in difficult ground were common, sub-samples were generally of a lower quality standard from a technical (Eurocode) and laboratory testing perspective, and slopes were challenging to climb and work on.

The ability to deploy slope climbing equipment also improved safety standards when operating on cuttings and embankments, as it was no longer necessary to bench out working platforms by hand, the slope climbing chassis was equipped with sufficient space to provide a flat work area. Th e platform hand rails, and toe boards provide protection form the risks of working at height. The addition of temporary stairs further improves the access to and from the machines when positions are on the steepest slopes.

Another good example of BDA innovation was the recent work BDA member company Dunelm undertook on behalf of Network Rail, at Doncaster Railway Station. Specifi cally, Dunelm was requested to undertake a ground investigation for a railway bridge replacement scheme at the station. Th e specification required boreholes to be advanced to rockhead or competent strata with in-situ Standard Penetration Tests (SPT) and Super Heavy Dynamic Probing (SHDP). Recovery of samples for geotechnical laboratory testing was also required.

The investigation was undertaken on Platform 8, which was located at the furthest point from the station access and as such access to the borehole locations was challenging, with the route passing under the station through an underpass and series of narrow doorways and pedestrian lifts.

In addition to the difficult access, the work was required to be undertaken at night to reduce the impact on the busy railway station and given the proximity to Network Rail’s infrastructure, the rig was operated and supervised by Dunelm’s in house PTS certified drilling team.

With the many above ground investigation requirements and access constraints, the obvious choice of rig to undertake this ground investigation was a bespoke modular windowless sampling rig, which once assembled, has the exact capability as a standard tracked windowless sampling rig.

Innovatively, the rig was fully dismantled and mobilised to the borehole locations in sections, using a suitable wheeled trolley and reassembled once at the location of the boreholes on platform 8. The rig could then be quickly moved between each borehole location without being fully dismantled, offering advantages of safety, speed, and efficiency. Being able to get competent staff with appropriately designed and certified equipment onto an awkward position, where working times are hugely restricted, to obtain high quality, reliable data, should never be underestimated. Th e BDA audit scheme is the only independently certified mechanism that can provide this assurance for all Client bodies in the UK currently.

Th e BDA Audit also has several other what may be considered non-tangible benefits too, such as the recognition it offers employees within a business. By endorsing work practices, technical knowhow, quality and compliance standards, as well as record keeping, employees are motivated to perform better, with a sense of pride in doing the job correctly.

Specifying site investigation specialists, or drillers, which adhere to the correct standards and procedures, as defi ned by the BDA Audit, will minimise risk and has also the knock-on eff ect of raising industry standards more widely, which is not only good for the drilling sector, but also for the success of all rail infrastructure projects.

Richard Fielden is Director of the British Drilling Association