Drilling will be carried out in two steps: first, dig a "navigation roadway" with a diameter of about 10 cm, and then expand it into a life-saving passage with a diameter of 66 cm with a heavy cutting machine. Due to the limited width of the roadway, it can only accommodate people with a waist circumference of about 90 cm at most. The Chilean government requires overweight miners to lose weight underground.
In addition, in the process of widening, the gravel in the roadway will fall into the mining area near the trapped miners. Therefore, trapped miners are needed to help clean up the rubble, which is expected to reach 3,000 to 4,000 tons.
However, experts worry that because the San Jose copper mine has been developed for many years, if it is drilled carelessly, it may lead to a collapse accident. On September 1 day, due to the discovery of geological faults, rescuers had to stop drilling and turn to mine reinforcement. Sugas, the chief engineer in charge of the rescue project, revealed the rescue "Plan B": widening the existing rescue channel. Previously, three rescue channels with a diameter of about 10 cm have been opened for underground ventilation, communication and delivery of materials. If one of the passages can be widened to a diameter of 7 1 cm, rescuers can be sent down.
It has been reported before that if it goes well, Plan B will only take about 2 months. However, Sugath told the media a few days ago that although there are different schemes, the rescue work will take at least 3-4 months.
At present, a drilling machine with faster drilling speed than Strata950 machine has been assembled and will be put into use on September 5. It will widen the rescue passage for transporting materials to 30 cm, so as to transport larger objects underground. Experts are studying whether the widened rescue passage can become the second escape passage. After being isolated from the outside world, it is impossible to obtain timely information such as rescue progress, material distribution and family status, which will aggravate miners' anxiety and insecurity. According to psychologists, it is better to provide true news, even bad news, than to give false good news. For example, there is an argument about whether to tell miners how long it will take to be rescued. Finally, when the rescuers told the truth that it might take a long time, the miners accepted it calmly.
Rescuers have opened three exploration wells for transporting materials, ventilation and communication.
First, dig a "navigation roadway" with a diameter of about 10 cm.
Then it is expanded into a vertical roadway with a diameter of 66 cm and a depth of about 700 meters with a heavy cutting machine.
Then use the elevator to rescue the miners one by one.
Burj Khalifa (828 meters)
700 meters underground, the temporary "home" of 33 trapped miners is small but fully functional.