Greig Wolfe tells us about some of the initiatives undertaken by Leighton Contractors (India)
Leighton first commenced operations in India over 10 years ago but it has only been in the past six years that it has really made its presence felt. The company has offices in Mumbai, Delhi and Chennai and has delivered projects across India ranging from oil and gas to building and infrastructure. Adhering to high international standards of quality and safety. To date, it has delivered over 20 projects in India. In executing and delivering these projects, it has, wherever possible, successfully applied up-to-date technology where it could positively contribute to the success of the project. Some of Leighton’s successful applications of technology in the local environment are highlighted below.
Offshore oil and gas
Leighton’s offshore oil and gas business has established itself as a leading contractor in the installation of single-point mooring terminals (SPMs) and large diameter subsea pipelines, as well as in smaller diameter rigid and flexible pipelines in the shallower end of the offshore environment. To achieve this, it has developed a fleet of modern, up-to-date pipe lay barges and installation vessels specifically designed to operate in conditions relevant to the designated market.
All Leighton vessels are built to the highest international standards and have the necessary certification and classification to operate internationally as well as satisfying the high standards demanded by the oil and gas industry. These vessels, designed and built under the supervision of Leighton personnel, have been so successful that the Leighton Eclipse has recently established an all-time record of 2,800 m of rigid pipe laid in a 24-hour period, beating all previous records for pipe laid in a single day in ONGC’s Mumbai High field.
To support offshore pipe lay operations, Leighton has on occasion conceived and built specialist plant and equipment where suitable plant has not been readily available. A particular offshore project recently undertaken by the company required that a large amount of cement grout be mixed at a high rate of output to minimise the amount of time required to place it in a subsea operation. The high rate of mixing was specified to reduce the very high cost of offshore subsea operations to a minimum. After investigating the supply of suitable equipment locally, Leighton decided to design and build its own plant to achieve the required output. This plant was specifically built to operate in demanding offshore conditions, and has proved successful in achieving the requirements.
In 2008, Leighton was awarded a contract by Bharat Oman Refineries Ltd for the installation of a SPM terminal and pipeline near Vadinar in the Gulf of Kutch. The total length of the marine pipeline was about 16 km, a portion of which had to be built through environmentally sensitive mangrove and intertidal areas. The extremely shallow areas along with limited access and the alignment of the pipeline made it difficult for normal pipe lay vessels to be used for the installation. Along with some careful pipeline engineering, Leighton was able to develop and build a linear winch capable of installing the 2,700 m of 48” pipeline in extremely shallow water without the necessity for any vessels to enter the area.
Infrastructure projects
Leighton has recently secured the engineering, procurement and construction (EPC) contract for the construction of a two-lane, 9 km tunnel with a parallel escape tunnel on the Chenani to Nashri National Highway. This challenging tunnel project will provide a safe and improved alternative to the present 41 km section of particularly difficult and hazardous road. The main tunnel will have a cross-sectional area of about 175 sq m and the escape tunnel 36 sq m; the rate of advance in the driving of these tunnels will be 2.7 m per day. Leighton will construct these tunnels using the drill and blast method employing NATM with sprayed concrete support. This method of construction, also known as a ‘design as you monitor’ approach enables the rock support and construction method to be varied based on the measurements and observations of rock conditions and convergence and divergence of the linings encountered.
Leighton intends to employ the latest computerised Jumbo for the drilling of blast holes, anchor holes and de-watering holes, while tunnel profile and alignment control will be continuously monitored with computer-aided stations and laser technology. The computerised multi-head jumbo drilling machine will enable all drilling details to be programmed into the machine and automatically accessed as required during the drilling sequence. The type of information programmed into the machine will include drilling pattern, hole diameter and drilling depth of all standard holes. Rock support in the way of rock-bolting will be determined from the support classification, with drilling being carried out by the Jumbo. The secondary support will be with a layer of steel-fibre reinforced shotcrete applied in a fully automated process.
