ORKNEY COMMUNITY WIND FARM - FARAY

The only access onto the island comprised a concrete ramp on the southern tip of the island. During the planning period, both the drilling supervisor (DS) and project manager (PM) from CA attended a site visit with Leask Marine to check access for the proposed vessels. During the visit, it was noted that despite a high tide, the use of the concrete ramp would not be suitable due to the limited water depth and risk of damage to the underside of a landing craft. With the support from CA, Leask Marine fabricated an additional steel ramp to provide greater flexibility and permit mobilisation/demobilisation over a larger tidal window. Leask also utilised tide tables and experience of delivering similar work to determine the optimum tidal windows to deliver the GI.

During the site visit, the PM and DS met with the tenant farmer to discuss optimum access routes around the island, along with agreeing on a rental agreement for the use of the ‘schoolhouse,’ which was used for rudimentary storage/welfare and provision of core logging facilities.

All of the drilling plant and consumables were mobilised to Orkney Mainland before being craned onto a multicat vessel at Kirkwall Harbour. The multicat sailed to deeper offshore water south of Faray and craned the plant off onto the landing craft, which made multiple trips to Faray during an optimum spring tidal window, as agreed during the planning. The full mobilisation and demobilisation were undertaken during one visit each, which is testament to the planning between CA and Leask Marine.

Two Fraste PLG drilling rigs, two tracked dumpers, one electric-powered utility terrain vehicle (UTV), and a 13-tonne tracked excavator were mobilised, along with drilling, sampling, and backfill consumables. The boreholes were constructed with a PWF coring system, with water as the flushing medium.

Due to the lack of fresh water on site, the boreholes were drilled with seawater as the flushing medium, with fresh water mobilised from the project outset in 1000-litre IBCs to permit flushing of the plant on a daily basis. The trial pits were excavated using the 13-tonne tracked excavator, which also supported daily plant movements, along with undertaking small-scale reinstatement works as the GI progressed. All of the trial pits were supervised by an archaeologist as provided by the Orkney Research Centre for Archaeology.

Seven boreholes were installed with a 50 mm standpipe, complete with both remote and manual access groundwater level monitoring instrumentation. Prior to demobilising the island, the functionality of each monitoring instrument was checked to ensure the data was feeding into a CA-produced bespoke database that can be accessed by MM for up to 12 months.

The CA site supervisor maintained constant communication with the project team and respective designers to confirm progress and inform on any changes to the proposed programme. Exploratory hole logs were issued on a daily basis, with typed draft logs and an associated blank test schedule issued within 48 hours of exploratory hole completion. Environmental samples were dispatched from the site three times a week. All the laboratory testing was undertaken within the agreed programme, with the draft report and AGS data issued two weeks after the completion of lab testing as per the agreed contract.

The GI was delivered at Faray through June 2024 by a dedicated delivery team, who stayed on Orkney Mainland until the fieldwork was completed. Despite the challenges, namely remote access and the choppy boat trips, we delivered the GI in a compressed 11-day period to meet the client’s needs. Support from Leask Marine was fundamental to the successful delivery of the GI and demonstrates the importance of collaborative working.