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Tender Value: £0.5M
Client: Aone+ Integrated Services


Rotary Drillholes

Advanced at various locations along the alignment of the carriageway section to provide information on geo-hazard issues such as mine workings.


Observation Trial Pits

Mainly to determine the position of off-carriageway utility services.


Cable Boreholes

To establish the soft ground conditions, in places to depths in excess of 50m, comprising thick strata of laminated clay and glacial till.


Difficulties (to Overcome)

Difficulties such as night-works, old mineworkings, road carriageway operations, slope slip investigation and deep drilling (50m+).

The scheme involves the investigation of c. 6.2 kilometres of the A1(T) south of Gateshead between the Metro Centre Junction (in the west) and Coal House Junction (in the south-east); comprising both northbound and southbound carriageways. The scope of works included a range of intrusive techniques, with a large proportion of the exploratory hole work carried out during night-shift with associated enabling lane closures along the A1(T) mainline section (either side of the highway). At its peak there were seven drilling crews involved undertaking the scheduled work, which towards the latter stages, was evenly split between night shift and daylight hours.

Good working relationships were maintained with the Client and an appreciable local knowledge of the ground conditions (as well as the local environment) assisted in delivering the project effectively. Due to the company's operational flexibility, in-house crews were tasked where necessary to undertaken the soft-ground and coring operations in the same exploratory holes. This reduced the amount of plant transactions, egress and access to exploratory positions. Geo-hazards had a bearing on the works, specifically the potential for encountering actively gassing (venting) abandoned coal workings. During drilling risk levels were checked using GA2000+ monitoring instruments to ensure that the welfare of operatives was not being compromised. All works were carried out in accordance with a Coal Authority permit and followed the agree methods of working.

The main challenges connected with this contract was putting together a site team (engineers and drilling operatives) that could cope with the long duration of night-shift work needed to complete and supervise the drilling programme. Availability of in-house site operatives and our own drilling capacity assisted the contract process significantly, particularly the organisational logistics to maintain efficiency and in the process deliver on programme expectations.