Corrtech International Ltd and Bluegrass Technologies used the H-512 (HK500M) to lay the 660mm diameter pipeline 3.5km across the Subansiri River in Assam.

The HDD rig has a pulling force of 500 tons and a pushing force of 100 tons.

“Due to the enormous length of the 26in (660mm) pipeline section there is a huge friction force acting while pulling in the pipeline. That’s why the customer decided to buy the strongest HDD that we have in our portfolio,” said Herrenknecht.

The HDD rig was the first to be built at Herrenknecht Asia Thailand (HAT). A second rig is now in production at the facility.

“The expansion of our premises in the country gives us other opportunities on the market thanks to this new production site,” said Herrenknecht.

Numaligarh Refinery Ltd’s (NRL) refinery expansion project involves laying of a pipeline 1,635km from Paradip Port in Odisha to Numaligarh. The refinery is also trebling its annual output. The project, which is the single largest investment in north-east India, is part of the government’s Hydrocarbon Vision 2030 for North East India.

The pipeline passes through five states and crosses all the major rivers of east India – the Ganga, Jia Bharali, Subansiri and Brahmaputra – for which HDD will be used. 

NRL said the Subansiri River, which connects Lakhimpur in the north and Majuli in the south, is one of the of the most challenging HDD sites because of the 3.5km length for a 660m diameter pipe.

“The remote site made it more challenging due to non-accessibility of the area which remains flooded most of the year, leaving a working window of four to five months during November to March,” NRL said.

In two to three months’ time the pipeline will be laid across the Ganga and Brahmaputra rivers, completing all major HDD crossings for the project.

NRL plans to commission the line by mid-2025.