Come join us in Acapulco, Guerrero at the 2021 Mineria International Convention and learn more about Robbins latest innovation, the MDM5000. The machine is currently boring a mine access tunnel in andesite and shale with quartz intrusions. It has successfully bored 1,700 m of tunnel. We will have materials at our booth 706-706A showing the astonishing work that has been made at Fresnillo mine in Mexico. Visit Robbins international experts who are ready to discuss a solution for your next project with our revolutionary machines.
Find out more about Robbins’ innovative solution for underground mining, the MDM5000 (standing for Mine Development Machine with dimensions of 4.5 m x 5.0 m). The MDM5000 is the world’s first successful rectangular boring machine for hard rock, and creates a flat invert as it bores for road access.
A rectangular tunnel boring machine, known as the MDM5000, has successfully bored a hard rock tunnel with flat invert in Fresnillo, Mexico. Watch the video to find out more from Robbins personnel, mine officials, and those operating the new machine on a daily basis.
Robbins’ latest innovation is making good headway on a non-circular tunnel excavation in hard rock. The rectangular TBM, known as the MDM5000 (standing for Mine Development Machine with dimensions of 5.0 m x 4.5 m) is capable of excavating a flat tunnel invert for immediate use by rubber-tired vehicles. Employed by Mexico’s oldest silver mine, Fresnillo Plc, the MDM5000 is boring a mine access tunnel in andesite and shale with quartz intrusions that has defied earlier attempts using roadheaders. The successful operation is the result of extensive discussions between Robbins, who designed and supplied the machine, with TOPO machinery and Fresnillo Plc. View the video of the machine in action here.
“We decided to work with Robbins for their experience. A lot of people have tried to provide these kinds of machines but nobody has done it. Robbins used their experience and their skills to provide us with a rectangular profile machine,” said Fidel Morin, Projects Superintendent for Fresnillo Mine.
The technology is not only useful for the mining industry, but also for many applications in civil tunneling. While other machines have been developed for soft ground, the MDM5000 represents the first successful foray into rectangular hard rock tunneling. “We’re very pleased to add non-circular tunneling to our wheelhouse of solutions that continues to include TBMs, conveyors, cutters, and more. We see applications for the MDM wherever a rectangular profile is needed, such as train tunnels requiring a flat invert. In a traditional circular tunnel, the invert is filled or an invert segment is needed, but with the MDM 30% less rock is required to be removed from the profile,” said Robbins President Lok Home.
With more than 1,700 m of advance thus far at rates up to 52 m in one week and 191 m in one month, the MDM is significantly faster than drill & blast excavation. “We’re making history. Fresnillo is always looking for new technology, and we believe that the usage of the MDM5000 is going to be something extremely successful, not only for our company but also for the industry,” said Morin.
The MDM5000 has undergone major component enhancements during the course of its successful bore at Fresnillo mine. It was first transported to the -695 m level of the mine and underwent final assembly and launch in a cavern, where sections of the MDM were moved by crawlers and pieces were lifted by hoist. The machine is now boring a 270-degree spiral to end above the original tunnel. It will then be backed up to the original tunnel and continue driving straight ahead.
Developed for use in rock up to 200 MPa UCS, the MDM5000 utilizes disc cutter technology proven on traditional, circular TBMs. During excavation a reciprocating cutterhead and swinging cutterhead motion create a rectangular cross section tunnel.
The MDM offers a number of advantages over drill and blast. MDM tunneling has advance rates roughly twice those of a drill and blast heading, and results in smooth tunnel walls, less overbreak, and minimized ground support. The increased advance rates are partly due to the machine’s continuous progress, unlike drill and blast operations where crews must exit the tunnel during blasting for safety. In addition, simultaneous ground support installation further increases overall advance rates compared with drill and blast operations that must install ground support sequentially.
View the machine boring at Fresnillo mine: https://youtu.be/mgFopWaf220
Much like the face of a TBM, tunneling’s wheels of progress are always turning. Join us as we check in on projects across the globe—including a breakthrough in Japan, record setting progress in Canada, and a new project ramping up in Nepal.
Setting Citywide Records in Toronto
Exciting progress is being made deep below Lake Ontario. The 7.95 m (26.1 ft) Single Shield Robbins TBM boring the 3.5 km (2.2 mi) long Ashbridges Bay Outfall tunnel is seeing record setting progress for the City of Toronto, ON, Canada. The machine, operated by contractor Southland Holdings, has recently completed 30 rings in a single day, at 1.5 m (5 ft) per ring, equating to 45 m (148 ft). With this accomplishment, the machine and crew surpassed a previous best day of 21 rings at a project with similar specifications. The Ashbridges Bay Outfall is anticipated to be the largest wastewater outfall in Canada and will improve the city’s shoreline, beaches, and Lake Ontario’s water quality.
A Third Set of Records in Esme, Turkey
If two sets of records weren’t enough, the 13.77 m (45.18 ft) diameter Robbins Crossover (XRE) TBM boring Turkey’s Esme-Salihli Railway Tunnel has just set another precedent. In July 2021, the speedy machine outdid its previous records in the size class of 13 to 14 m (43 to 46 ft), boring 167.4 m (549.2 ft) in one week and 511.2 m (1,677 ft) in one month. The rates are the fastest ever recorded for any TBM over 13 m (43 ft) in diameter! They even surpass those set over a decade ago at the Niagara Tunnel Project by a Robbins 14.4 m (47.5 ft) diameter Main Beam TBM. Check out the records here.
Breakthrough at Tamagawa
In June, JV contractors Obayashi & Kumagai celebrated their final breakthrough at the Tamagawa HPP #2, Lot 2 project in Yamagata Prefecture, Japan. During the bore, the crew faced unpredictable soft ground conditions and other challenges. To surmount these issues, an airborne electromagnetic survey was conducted for predicting soft ground conditions ahead of the tunnel surface and tunnel face stability was improved by using forepiling. The project, completed with the use of a Robbins 4.5 m (14.7 ft) Main Beam TBM, will supply 14,600 kw of renewable power to the region.
Double Shield to Bore Second Nepalese Tunnel
A record-setting 5.09 m (16.7 ft) Robbins Double Shield TBM is currently being rebuilt to tackle its second project for Nepal. The machine, which set multiple records and finished a year early at the Bheri Babai Diversion Multipurpose Project, has been chosen to bore the 13.3 km (8.2 mi) long Sunkoshi Marin Diversion Tunnel. Upon completion, the structure will divert part of the flow of the Sunkoshi River into the Bagmati river to irrigate farmland in the Tarai district. The project has been awarded to contractor China Overseas Engineering Co (COVEC), who will be bringing their expertise and experience from the Bheri Babai tunnel to this new endeavor.
History has been made twice over at Turkey’s Eşme-Salihli Railway Tunnel where a 13.77 m (45.18 ft) diameter Robbins Crossover XRE TBM has set new world records for best day, week, and month in the 13 to 14 m (42.6 to 46 ft) diameter range. The machine broke all three records first in May with 25.3 m (83 ft) in one day, 117 m (383.8 ft) in one week, and 345.6 m (1,134 ft) in one month, then again in June with 28.5 m (93.5 ft), 133.2 m (437 ft), and 455.4 m (1,494 ft) respectively. The TBM, which sat in storage for seven years before being newly upgraded for this project, proves the robust durability of Robbins machines.
The Crossover TBM surpassed all previous performance rates by a machine in its size range. The closest another 13 to 14 m (42.6 to 46 ft) machine has come to these numbers was a 13.7 m (45 ft) diameter mixed ground TBM that achieved a 7 m (23 ft) average per day and a best day of 12 m (39 ft) at the Eurasia Tunnel project.
Onur Kansu, TBM Manager for project contractor Kolin Construction, attributes the machine’s success to the team operating it: “The most important reason for achieving fast advance rates is that we have an experienced and qualified team. If we open it up even further, such a team allows us to anticipate the malfunctions and to go to the solution in a very short time. In addition, all necessary maintenance is carried out on time, and the appropriate consumables are selected to increase the performance.”
The machine launched on its 3.05 km (1.90 mi) bore at the end of March 2021 as part of the Ankara-İzmir High Speed Railway Project for the Turkish State Railways (TCDD). Thus far the machine has encountered a mix of mainly mudstone with gneiss. “When we look at the overall tunnel geology,’ said Kansu, “we are excavating in complex and weak ground. In this geology, the advantages of the Robbins XRE TBM are highly favorable. The Robbins XRE TBM shows high performance in both complex and weak ground. It should also be noted that the TBM is very strong when looking at parameters such as torque and thrust.” To get through the challenging conditions, the large diameter XRE has a number of unique features. The large diameter design enables both a screw conveyor and belt conveyor to remain in place, enabling swift conversion between modes, and operation in full EPB and hard rock modes.
Regarding the future of the Turkish tunneling industry, Kansu is optimistic about the effects these new records will have: “It has been seen how well the engineers and application teams in Turkey have excelled in complex geologies and the large-scale tunneling industry. At the same time, it has shown to the whole world, especially Turkey, that with the right choices, it is possible to carry out excavations of this scale and complex geology without any problems and quickly. This project will be a pioneer in the Turkish tunneling industry, showing that faster and more economical tunnels can be built.”
In Spring 2021, the second of two 6.65 m (21.8 ft) diameter Robbins Crossover XRE TBMs made its third and final breakthrough for India’s Mumbai Metro Line 3. The first machine made its final breakthrough for the project in late April. The tunnel drives were a triumph for joint venture contractor Larsen & Toubro and the Shanghai Tunnel Engineering Company (L&T – STEC), as the crew and equipment overcame unpredictable terrain, high-pressure water ingress, and government-imposed lockdown orders during the Covid-19 pandemic.
The two custom-built machines were selected to bore parallel 2.9 km (1.8 mi) tunnels between the Cuffe Parade station and CST stations, breaking through into several station sites along the way. “It is the first time in India that Dual Mode, Crossover type TBMs equipped with a horizontal screw conveyor and high torque / high speed (two-speed) cutterhead drives were used. Overall, the performance of the Crossover TBMs was found satisfactory and we are in the process of shifting these TBMs for the L&T Chennai Metro project,” said Mr. Palwinder Singh, Head – Tunnel Construction for the L&T – STEC JV.
In another first for India, the Crossover TBMs employed a unique technique in a 554 m (1,820 ft) long section from Hutatma Chowk to CST stations. They were used in the benching of the NATM Platform tunnel through basalt rock (removal of the bottom section of rock remaining in the station after conventionally removing the top section). “This requires fine control on the operational parameters of the TBM because only 25% of the cutterhead is excavating the rock mass, while the remaining 75% of the cutterhead has no contact with rock or soil. In addition, the TBM was relaunched without using a reaction frame, instead taking reaction from half segments erected during the benching of the NATM Platform Tunnel. These innovative concepts were accomplished for the first time in India at Mumbai Metro Line-3, Package 1, and I therefore have many reasons to feel proud on the completion of tunneling,” said Singh.
L&T – STEC made impressive progress throughout tunneling despite the many exacting circumstances surrounding the scope of work. Above ground, the joint venture not only had to navigate the restrictions of working within an urban environment, such as limited work hours and the slow removal of muck due to minimal space and traffic, but also faced concern for major structures such as the Mittal Towers and the historic Bhikha Behram Well located along the tunneling route. The Crossover TBMs excavated with only 15 to 20 m (49 to 65 ft) of cover separating them from these important structures, which had to be instrumented to monitor vibrations, movements, and potential settlement.
Underground, L&T – STEC faced a complex geological mix of fresh greyish basalt, soft volcanic tuffs, shale, and breccias—consolidated rocks of angular fragments of disintegrated volcanic rock. One of the biggest concerns, however, came from the tunnels’ proximity to the coastline of the Arabian Sea. During one point, TBM 1 was only 25 m (82 ft) from the coastline, with the invert level of the tunnel running approximately 22 m (72 ft) below mean sea level. As anticipated with circumstances such as these, the Crossovers faced a significant amount of groundwater with up to 300 liters/min during their excavation.
Despite these obstacles, the TBMs were still able to maintain impressive rates. TBM 2 even completed one push in a swift 14 minutes. “In fact, the boring rate of the Crossover TBMs was never an issue for us. It was only limited by the rate of muck removal and we could have finished the tunnels much faster,” said Singh.
L&T engineers were highly involved in the specifications and designs of the machines and worked closely with Robbins to prepare for the challenges the project presented. While L&T had extensive tunneling experience, tunneling with a Crossover machine was entirely new to them. To remedy this, Robbins provided a team of key personnel to train L&T in all aspects of the machines’ design and operation. “Working with Robbins field service was more than satisfactory. Even during the Covid-19 pandemic times, Robbins field service was available 24 hours a day, 7 days a week. What else can one expect?” said Singh.
Each milestone reached on this project is another step closer toward significantly improving the lives of Mumbai residents. As the financial capital of India and one of the most populated cities in the world, Mumbai is faced with an excessive amount of road traffic. It currently takes up to two hours to drive the 25 km (15 mi) distance from Cuffe Parade to the airport—the same trip on the finished metro will take a mere 50 minutes. The completion of Mumbai Metro Line 3, which is expected in 2025, will not only save residents transit time, but is expected to initially decrease road traffic in the area by 35%, reducing daily fuel consumption by 460,000 liters.
The choice of TBM type is never easy, but it becomes especially challenging when faced with a hard rock tunnel with expected high water flows and pressure. Slurry Shield tunneling has a long history of being used in these conditions to minimize the risk, though this method has brought with it other risks along with cost considerations. At recent projects around the world, another method has been proven to effectively manage these project risks without utilizing Slurry Shield tunneling: Shielded, Non-Continuous Pressurized (NCP)-TBM tunneling in rock with a comprehensive grouting program. In this paper, the authors will analyze the use of Shielded NCP TBMs at projects around the world as compared with slurry shield tunneling in rock under water pressure. Recommendations will be given in order to establish a clear picture of the optimal tunneling method.
Event Name: Cutting Edge Conference
Dates: November 15-17, 2021
Location: Dallas, Texas, USA
Come visit Robbins at the Cutting Edge Conference, and learn more about the largest hard rock TBM ever to operate in the USA at the Mill Creek Project. The 11.6 m (38.1 ft) diameter Robbins Main Beam TBM is excavating an 8 km (5 mi) long tunnel in Dallas, and is the conference’s main field trip. The annual Cutting Edge Conference examines the latest advances in tunneling technology, its methodology and how they can be harnessed to assist the nation’s major upcoming underground projects. Visit Robbins at our booth and talk to our experts with decades of experience on our latest projects and products.
Covering more than 30 acres, The Utility Expo is the largest event for utility professionals and construction contractors seeking the latest industry technologies, innovations, and trends. Visit Robbins at our indoor booth N1961 and talk with our expert staff on our latest products and projects. We look forward to seeing you there!