Table of Contents
Ease of Boomer Operation
About Atlas Copco
This paper discusses a project that is in schedule for the boosting of water supplies for the Malaysian Capital Kuala Lumpur, even though it means complicated tunneling in difficult ground and mountain terrain. The citizens of Kuala Lumpur may probably never realize that there has been an increase in their water supplies. However many of them will never forget the ordeal of bringing raw water from the mountains to the city.
The Ministry of Energy, Green Technology and Water commenced this project known as the Pahang Selangor Raw Water Tunnel in 2008 with the construction of the Kelau Dam on the Semantan River, northeast of the capital. The project includes a 24 km2 reservoir as well as the excavation of a 5.2 m width, 44 km length diversion tunnel which will carry the water to a treatment plant on the outskirts of the city center.
There water treatment will be done for both industrial and domestic purposes. The excavation work is on schedule to meet the 2013 completion date however setbacks and complications have threatened progress.
Location of the Semantan Water Transfer Tunnel which will boost supplies in Kuala Lumpur.
Even though the site is not very far from the city, the mountainous terrain presents key challenges. Three different types of tunneling has been employed here over two years tunnel boring (TBM), underground blast and drill using New Austrian Tunneling Method (NATM) and open cut also using NATM.
NATM, the method of tunneling in soft ground with the emphasis on ground support, is used here for the four adits totaling 8.6 km, as well as for the 4 x 4.7 m cut and cover culverts at each end, totaling 1 km. The remaining 34.4 km of the main tunnel will be driven by a TBM. The adits (named NATM 1, 2, 3 & 4) will enable access for equipment and will be equipped with service facilities for drill rig maintenance, concrete mixing and water purification systems.
Other than water ingress, which in several cases can be as high as 10 000 l/min, other challenges are presented by the inconsistencies in rock formations. For instance, the Lepoh fault that runs through the project center has fractured rock on either side. At a certain point, the tunnel crosses under a river with a fractured formation causing even more water ingress.
In the NATM 3 section of the main tunnel, the Atlas Copco Boomer L2C copes with varied rock conditions and considerable water ingress. Good results have been obtained from the blasting and drilling as well as the need for stabilization. The construction is done by the SNUI Joint Venture comprising four contractors Shimizu and Nishimatsu of Japan and UEMB and IJM of Malaysia. From the start, Atlas Copco has been involved in this project and has four Boomer face drilling rigs on site as well as ground engineering equipment.
Ease of Boomer Operation
Sudhan Bahadur Shreepali, a Nepalese Boomer operator having around 8 years of drilling experience, has used the Boomer rigs but this is the first time he is using the computerized Boomer L2C. He said that the drilling is highly predictable and the east side rock is quite good and the west side is less competent. Drilling under the river was a challenge but this rig made it easy, he added. The drillers work two 12 hour shifts per day and at a specific time, the NATM 3 adit was being advanced at a rate of 8 m per day, taking Shreepali approximately two hours to drill a round.
Most drilling is done by three Boomer L2C rigs. These are equipped with COP 1838 ME rock drills and use Secoroc 105 mm bits for the pilot holes and 45 mm bits for the blast holes. A Boomer 352 is also present on the site.
SNUI Project Manager Takashi Kawata stated that after nearly two years, the NATM segments are either on schedule or as much as three months ahead of schedule. NATM 3 was delayed because of the slow progress under the river, but quickly moved back ahead of schedule once it made it beyond the river. NATM 4 was also delayed because of soft ground conditions, though for the most part, the rock has been consistent granite.
Kawata added that they have been getting excellent results with blasting and drilling and also that the performance of the rig far exceeded expectations. For instance, the NATM 2 adit was 138.3 m per month but actual drilling averaged 149.4 m month. NATM 1 was the only section that had fallen behind schedule due to heavy water ingress. Once the problem area was passed, excavation again outperformed forecasts for two consecutive months. Along with the drill rigs, an Atlas Copco COP 1838 ME rock drill is used for drilling 76 mm probe holes in advance of the TBM while all rock tools used on site are also from Atlas Copco. With high equipment productivity and trained drill crews, citizens of Kuala Lumpur may well be receiving their new water supply sooner than they expected.
Water carrier: The 44 km long tunnel with its cut-and-cover culverts and four adits. The culverts and adits (brown color) are driven by Atlas Copco Boomer L2C rigs while the main tunnel is being driven by a TBM.
About Atlas Copco
In close cooperation with customers and business partners, and with more than 130 years of experience, Atlas Copco innovates for sustainable productivity.
- The products and services include compressors, expanders and air treatment systems, construction and mining equipment, power tools and assembly systems.
- Atlas Copco's customers are located almost everywhere on the globe. To them, Atlas Copco is a local company; at the same time, the Atlas Copco Group is a global enterprise with worldwide resources.
- Headquartered in Stockholm, Sweden, the Group’s global reach spans more than 170 markets, with its own sales operations in more than 80 countries. In the other countries, the products are marketed through distributors and service networks.
- The Group has production facilities in more than 20 countries. Manufacturing is mainly concentrated in Belgium, Sweden, Germany, the United States, India and China.
The objective of Atlas Copco’s corporate responsibility work is to be a good corporate citizen in each market. This is done by making a positive impact in economic, environmental and social aspects, and through employee pride in the Group’s values.
Atlas Copco’s vision is to become and remain First in Mind-First in Choice® for its stakeholders, which is also the driving force of the Group’s corporate responsibility strategy
With a tradition of innovation dating back to the Group’s founding in 1873, the core business remains much the same, with today's equipment delivering an unparalleled level of efficiency.
This information has been sourced, reviewed and adapted from materials provided by Atlas Copco.
For more information on this source, please visit Atlas Copco.