Tunnels and bridges, improving Argentina's major road link
First publishedin World Highways
A road improvement plus tunnel and bridge building contract in an area once inhabited by dinosaurs in northern Argentina, is a small but key part of an ambitious project to complete a road that will eventually link the Atlantic and Pacific coasts of Latin America - Adriana Potts reports
Remote, rough and spectacular are words that come to mind when describing the mountains of Ischigualasto in Argentina's northern province of San Juan This is the only place in the world where an undisturbed sequence of rock deposits representing all of the Triassic period (the age of the dinosaurs) can be found. This unique place is so precious that it has been declared a World Heritage site by UNESCO
Here, Argentine mining and construction company Jose Cartellone
Construcciones Civile (JCCC) is currently working on a turnkey contract to deliver a new 24km stretch of road complete with six tunnels and ve bridges as part of Ruta 150 near the Chilean border. This project is part of wider government plans to open a corridor connecting the Atlantic Ocean with the Paci c Ocean, in Chile (See map on p23).
During the last decade, the Argentine Government has been pouring huge resources into developing the country's road network in order to connect Argentina internally and with other South American countries. This strategic plan has boosted the national construction industry and hundreds of infrastructure projects are changing the face and transport ef ciency of Argentina.
Amongst these projects, a special place is occupied by the inter-oceanic corridor that will link the ports of São Paulo and Porto Alegre on the Atlantic coast of Brazil with the port of Coquimbo on the Paci c coast of Chile. This link crosses six provinces in northern Argentina, including San Juan, where it takes the name of Ruta 150.
This corridor will also eventually connect Argentina with Chile through an international tunnel below the Paso de Agua Negra border crossing. This project, which is scheduled to begin this year, will become the Mercosur route to the Paci c Ocean, reducing export costs for products from Brazil, Paraguay and Argentina to the countries of East and Southeast Asia.
JCCC is building a short but complicated sector of Ruta 150 at the Ischigualasto Park region, an old geological formation, older even than the high Andean mountain range, which rises between Argentina and Chile 100km to the west.
Once a fertile paradise for the dinosaurs that roamed the land, this area is now a hostile desert with temperatures ranging from -10°C to +45°C, just a few days of rain per year (which can turn into electrical storms), and winds that blow every afternoon at 20-40km/hour. The area is subjected to the occasional 'Zonda' from the west, a powerful wind which blows in spring and can reach 100km/hour and increases the heat to an unbearable level.
Training has been provided by the manufacturer to ensure the machine operators can utilise the equipment with optimum performance.
"The Ischigualasto Mountains present both topographic and geological dif culties, but they are not very high. At 1,800-1,900m above sea level, we are lucky not to be at very high altitude. In other projects we work at over 3,000- 4,000m above sea level and we know how complicated that is," said Daniel Castro, manager road construction and mining, JCCC. "This area is quite remote so we're isolated from important urban centres.
The nearest place where we can nd resources is San Juan city, about 300km from here. For instance, we have to get water, for both human consumption and for construction, from a place over 150km from here. We have trucks that bring water all that way, travelling during the day and night. That's the biggest challenge of this project; the long distance to reach necessary resources, including personnel, equipment and all they need to survive and work in the desert." Environmental demands are even harder on this site because of its location in a preservation area created to protect the fossils. This dictates not only the direction that the roads and tunnels are permitted to take but also their characteristics. It also affects other areas of the project.
"The same happens with our two camps," said Mario Frate, project manager.
"Nearly a year ago, when simultaneous excavation of the tunnels was in full process, we had over 600 workers living on the site. Now we have 480 but it still is like a small town in the desert," he said, explaining that drilling crews work at the site for 14 consecutive days followed by seven days off while ground engineering and civil construction teams work 11-days on and three days off.
Sophisticated tunnelling equipment from Atlas Copco has helped maximise efficiency of the drill and blast operations for the new highway tunnel.
The camp has to guarantee food and water supply, medical care, transport from San Juan city to the camp and inside the site itself for all the workers. Furthermore, sewage has to be treated and oil, fuel and worn tyres have to be disposed of. "All of this requires a huge technical and logistic effort, including from the environmental point of view," Frate said.
"There are speci c environmental procedures for the control of all of these issues. They are supervised by local and national authorities and also by JCCC's environmental manager, who works independently from the site management." The project includes 24km across the mountains, with tunnels, bridges and new roads and 15km of an existing road that has to be rebuilt.
"Our contract is "key in hand," the complete section, from the construction of auxiliary roads for access into a virgin area, excavation and construction of six tunnels and ve bridges, all the necessary earth movement work, ground levelling, drainage systems, asphalting, guardrails, traf c signs and other safety work," explained Castro.
The rock in this area is not ideal for tunnel excavation - it is mostly consolidated sandstone formations and heavily fractured shale - so due to the dif cult geology some of the original plans had to be changed and eventually a six tunnels/ ve bridges solution was chosen.
Fausto Cervini, tunnel production manager, who has extensive international tunnelling experience, explained, "In 20-30% of the excavations we found rock of medium dif culty which we call Type 3, and diffcult to very diffcult rock, Type 4 and 5, in the rest.
In tunnel six we even found pure sand that demanded a lot of support work in the initial stage." Given the geotechnical dif culty presented by the rock and ground to be excavated, JCCC had to use a combination of methods, mechanical and more traditional drill and blast.
Seen above, it is clear why the tunnel section provides the best way to cross this difficult landscape.
"The tunnelling work was very difficult, but we rose to the challenge," said Castro, explaining that the tunnels are located 1,600-1,700m above sea level and have a total length of 2,400m; the longest being 500m. They are 9.5m high and 12m wide with 95m² cross-section.
"We have taken the usual safety measures for the construction works of an underground project of this nature. Because of their short length, the tunnels don't have special re routes but they are illuminated and have side windows or exits for ventilation," explained Castro.
"All six planned tunnels are already excavated - in fact, they were all excavated by the end of 2011. They're open in all their sections but they're not ready for traf c to go through them yet," said Castro, adding that excavation is only about 60% of the work.
"After excavation comes shotcrete, rock support, bolting, road construction, in this case 7.75m wide, with concrete pavement inside the tunnels, and asphalting outside, drainage and shoulders." JCCC has excavated approximately 1,350,000m³ to open the nal section of the new road and has built three of the ve planned bridges so far. Castro said, "We have already completed about 70% of the work and the plan is to hand over the nished project in July 2013." For both surface and underground excavations, JCC is employing a number of equipment of different brands, including Caterpillar and Komatsu trucks and loaders and CIFA shotcrete equipment.
Underground, some of the key equipment that JCCC is employing in this project are two of the latest generation Atlas Copco drill rigs - a Boomer E2 C and a Boomer XE3 C, the latter being the rst of its kind in South America.
"The rigs arrived here at the end of 2010 and the beginning of 2011. We are very proud to be the rst ones to be using the threeboomed E3 C, in Argentina and in South America," said Castro. The E3 C rig features Rig Control System (RCS), which includes a laser guided drill function that allows the driller to choose the coordinates x, y and z and a PLC programme that de nes the exact place for each hole. The machine also features heavy-duty hydraulic booms BUT 45 and COP 1838 rock drills. "It is an excellent rig with a very high performance, even for Cartellone's demanding safety and quality standards. The cost of it is substantial, but in my opinion it is worth the price," said Castro, adding that the same is valid for the Boomer E2 C, which features the same technology but only two booms and therefore it is used in smaller tunnels.
Access to the construction site of the tunnel section section has been difficult, increasing the number of challenges for the team
With the new rigs we've been able to double the advance when compared with the older rigs, which were of a different brand," said Castro, explaining that tests were made in similar conditions and they gave a clear picture of the bene ts of these state of the art drill rigs, which work around the clock. "The best thing about these machines is that they are not complicated. Technicians from Sweden trained our personnel for 45 days and after that our drillers were able to operate the machines. Our personnel then trained other drillers, as the Boomers need to work continually.
The training was good; we haven't had any problems at all as a result of bad operation." Castro adds that if tunnelling is to be ef cient, it must operate "like an industry." "I believe that drilling, blasting and mucking is a continuous process. Continuity is The rigs arrived here at the end of 2010 and the beginning of 2011. We are very proud to be the rst ones to be using the threeboomed E3 C, in Argentina and in South America" Daniel Castro Road construction and mining manager a key factor and the service schedule has to be followed very closely. If something stops it, the advance is impossible." Diego Molina and his brother Luís are Ecuadorians and operate the XE3 rig in shifts.
They had already worked with computerised rigs in their country. "I think that made our adaptation a lot easier," said Diego Molina.
From the brothers' point of view, one of the most important features is the machine's comfort and its power when drilling. "The most important feature is, perhaps, the high reach cab, with a complete panoramic vision, 360° around. It give us control over the rig, we can be sure that there are not people close to the rig when operating, that there are no problems with the hoses," said Diego Molina. His brother says: "It is a very modern and advanced machine. We feel really safe with it." Castro added, "The drillers work in a comfortable and protected environment - the way everybody should work in a modern company." Mario Laudani, manager business line underground rock excavation, Atlas Copco Argentina said, "JCCC is a very demanding customer, but it puts equally high demands on itself. Its safety records in mining and civil engineering, its quality and its respect for delivery schedules stands out in the market.
The introduction of the first three-boomed Boomer in Argentina and in South America by Cartellone is not a coincidence." JCCC Founded over 90 years ago in 1918 by José Cartellone, JCCC is a solid family-run company with a prestigious story and whose commitment with quality, safety, and the environment has put it in a privileged position, both in Argentina and elsewhere in South America. JCCC was the first service company in the Argentine mining industry. The mining industry in Argentina is not as developed as that of neighbouring countries Chile or Peru, but today it is enjoying an extraordinary period of growth that began just over eight years ago.
"We were the first company working with Barrick in the Pascua-Lama gold project, in the high Andean mountains, with 2.5 million man-hours without accidents, incidents or lost time," said Castro.
Today, JCCC's range of work covers extensive activities in heavy engineering, underground excavation, hydroelectric plants, transmission lines, aqueducts, road construction, tunnels, bridges, port and architecture both for public and private projects. JCCC has operations in almost all Latin American countries and the Caribbean, as well as in Saudi Arabia.
In Argentina JCCC works in mining and road construction in the long highways, 12 and 14, which connect Buenos Aires with the northeast border of Brazil.
Walking with Dinosaurs
The Ischigualasto Park in the north-western part of Argentina, on the Chilean border, has the world's largest known collection of dinosaur remains from the Triassic Period, the first period of the Mesozoic Era, which ran from 248 million years ago to 65 million years ago.
A lot happened to the Earth and its life-forms during the Triassic Period but the most celebrated event was the evolution of the dinosaurs. These remarkable creatures emerged around 230 million years ago and dominated the planet until the end of the Mesozoic Era.
In Ischigualasto, almost all of the Triassic Period is represented in an undisturbed sequence of rock deposits, allowing researchers to study the transition of dinosaurs to ancient mammals.
Because of this, in 2000, Ischigualasto Park was designated a World Heritage site by UNESCO. Now, scientists from all over the world come to Ischigualasto to study its fossils.
Located 1,300m above sea level, Ischigualasto is an area of 600km2, characterised by typical desert vegetation and fauna - a hot and hostile environment. Average temperatures range from 35°C in summer to +20°C in winter.
Approximately 60 million years ago the rocky masses of the Andes tightened the Ischigualasto zone against the Sierras Pampeanas, exposing them to water and wind erosion. Here, in what is called today 'Valle de la Luna' (Moon Valley), nature itself has carved some amazing sculptures of unique shapes and colours, making this another major tourist attraction, besides the remains of the dinosaurs that once roamed the area.