January 7, 2020
When Mining & Construction visits, work is about 70 percent complete on the road that must be wide and smooth enough to carry a flawless mirror seven meters in diameter to the summit of northern Chile’s Chajnantor Mountain, more than 5 600 meters above sea level.
The Tokyo Atacama Observatory, funded by the University of Tokyo, will one day offer unparalleled views of the universe, which could help to determine its age. According to contract manager Claudio Alvarado, the principle challenges for the roadbuilding team are the lack of oxygen and extreme weather conditions encountered at such high altitudes.
Altitude sickness can cause headaches, vomiting and, in extreme cases, potentially fatal pulmonary edemas. But even a brief fainting spell can be fatal on the mountain. Each worker must carry their own oxygen supply and undergo medical checks several times a day from the onsite nurse. The high altitude also brings extreme weather – at night, temperatures are so cold that heaters must be used to stop fluids from freezing while last winter, heavy snowfalls closed the project for six weeks.
In January, Movitec took possession of an Epiroc PowerROC T25 DC to help them deal with the mountain’s difficult geology.
What role does the PowerROC T25 DC play at the project?
“We encounter lots of large rocks that we need to remove. However, we cannot use explosives because we are located within an astronomical area and blasting would affect the operation of the 66 telescopes of the Atacama Large Millimeter Array (ALMA), which are less than ten kilometers away. So, we use plasma blasting technology. The PowerROC drills a 51-millimeter hole up to two meters into the rock and then water is injected into the hole. When a pulsed electric charge is applied, the rock is shattered into tiny pieces.”
What's been your experience with the PowerROC?
“The machine has been operating on the mountain for about two months. It has worked very well, better than we expected, so we are very happy with the functionality that the equipment has displayed in the project. At night, temperatures can fall to fifteen to twenty degrees Celsius below freezing, which can cause the hydraulic fluids and fuels to freeze and make starting the equipment in the morning very difficult. However, with the PowerROC, we have had absolutely no problems with fluids freezing or starting up in the morning. Nor has it lost pressure when working at altitude.”
Is there anything you would like to improve?
“Perhaps the arm could be longer or more flexible, which would help on the complicated terrain found on the mountain.”
[On location: Chile]
The road to the Tokyo Atacama Observatory, to be built at the Chajnantor Mountain in Northern Chile, must be wide and smooth enough to carry a flawless mirror seven meters in diameter.
PowerROC T25 DC
Drilling method: Tophammer
Hole diameter: 51 mm–89 mm
Maximum hole depth: 18.3 meters