The steel pipes has arrived in Geraldton for APA Group’s Northern Goldfields Interconnect pipeline. (Credit: © APA Group)
Northern Goldfields Interconnect (NGI) will connect the emerging gas fields in the Perth Basin to the Goldfields region of Western Australia. (Credit: PublicDomainPictures from Pixabay)
The pipeline is designed for a minimum operating life of 40 years. (Credit: LoggaWiggler from Pixabay)

Northern Goldfields Interconnect (NGI) is an under construction pipeline that will connect the emerging gas fields in the Perth Basin to the Goldfields region of Western Australia.

The 580km pipeline was proposed and will be owned by APA Northern Goldfields Interconnect (APA), a subsidiary of APA Group. In November 2020, the company announced its plans to invest up to A$460m ($322m) to build the pipeline.

The construction of NGI began in 2022 and is expected to be completed in 2023. The pipeline is designed for a minimum operating life of 40 years.

Once complete, the NGI pipeline will improve natural gas supplies for the mining industry as well as support the region’s processing and power generation growth requirements.

Pipeline Route

The underground NGI pipeline will start from Ambania, around 50km east of Geraldton, and will connect the existing Goldfields Gas Pipeline (GGP) at approximately 40km south of Leinster.

The pipeline will traverse through agricultural land that will include a mix of cropping and pastoral land. It will also utilise existing infrastructure where suitable.

The NGI pipeline alignment was finalised following desktop and field studies.

Design and Specifications

The project involves the construction of a 580km long high pressure pipeline buried at a minimum depth of 0.75m.

The minimum depth of cover may be deeper up to 2m to 5m at specific locations such as third party infrastructure crossing locations, watercourses and to accommodate horizontal directional drilling (HDD) construction methods.

Several temporary work areas and infrastructure such as construction camps, bulk fuel storage, workshops and site offices, will be installed during the construction stage.

The above-ground infrastructure facilities for the NGI include the Rosewick offtake station, Ambania compressor station, Yoweragabbie scraper station, two mainline valve stations at Carlminda and Dandaraga, Wildara delivery station and Weebo inlet station.

The carbon steel pipeline will have an outside diameter of 300mm. Standard wall thickness will be 7.5mm.

NGI will have a maximum design capacity of 4.0 million standard m3/day of gas with design temperature ranging from -10⁰C to 65⁰C.

It will be capable of withstanding maximum design pressure of 15.3 MegaPascals (MPa).

According to APA, the pipeline is being constructed in accordance with the latest version of Australian Standard AS2885 Pipelines Gas and Liquid Petroleum to ensure the incorporation of best-practice standards.

NGI is licenced by a new Pipeline Licence issued under the Petroleum Pipelines Act 1969 (WA).

The NGI pipeline will connect to APA’s Goldfields Gas Pipeline (GGP) which is linked to APA’s Eastern Goldfields network, thus forming a 2,690km interconnected APA gas pipeline system network.

Key infrastructure

Rosewick offtake station

The Rosewick offtake is proposed to be located at KP0, adjacent to the DBNGP and immediately south of the Eradu North Meter Station. It will enable gas flow from the DBNGP to the NGI pipeline.

Ambania compressor station

The compressor station, constructed near the start of the NGI pipeline, will receive gas from the Rosewick offtake through an interconnecting pipeline and then deliver it to the NGI pipeline directed towards the tie-in connection to the GGP (Weebo inlet station).

Yoweragabbie scraper station

The Yoweragabbie scraper station will enable cleaning and inspection of the pipeline and will occupy an area of approximately 1.1ha. It will be located at approximately 13km south of Mount Magnet.

Mainline Valve Stations

The Mainline Valve Stations (MLVs) will enable to control the flow of gas through the pipeline. The infrastructure will include two mainline valve (MLV) stations- Carlminda MLV, and Dandaraga MLV.

Wildara delivery station

The Wildara delivery station located near the end of the NGI pipeline will enable control of the flow of gas from the NGI pipeline to the GGP.

Weebo inlet station

The inlet station will enable connection between the buried NGI pipeline from the Wildara delivery station to the hot tap connection on the GGP.

Contractors Involved

Nacap was awarded the NGI pipeline construction contract by APA following a tender evaluation process. In July 2022, Nacap officially commenced lowering in operations on pipeline project.

In October 2021, APA Group awarded WestStar Industrial’s engineering construction contracting business Alltype Engineering a $25m contract to deliver a new two-unit gas turbine centrifugal gas compressor station. The compressor station is known as Ambania Compressor Station.

In May 2022, Veris was awarded a $2.4m contract to provide surveying services for pipeline infrastructure related to the Northern Goldfields Interconnect (NGI) pipeline project.

In June 2022, Technology Metals Australia signed an early works agreement (EWA) with APA Operations, a wholly owned subsidiary of APA Group for certain early works regarding the proposed development of the Gabanintha Gas Pipeline. This pipeline will be linked to the NGI.