Erlang mountain tunnel application - CREG just signed a contract to supply one set of jumbo drill for Erlang mountain tunnel. This tunnel is the key section of Yakang expressway project.
This tunnel is 13.5 km long and located in western part of Sichuan Provence where the earthquake intensity is 8 degree. It crosses 13 large tectonic faults with a complex geology. The encountered rock is very variable, from extreme hard granite to weak mudstone. They said, each round before blasting they will make a site investigation drill about 40 meters long by using CREG jumbo drill to anticipate the geology, the parameter will be recorded for a prompt site analysis.
In general, the full face (83 m²) 150 holes drilling process will take 3 to 3.5 hours. It reduced the time about 25% comparing to traditional manual positioning/drilling system. The drilling speed is ranging from 1,7 to 2,5 m/min according to the hardness of rock. Overbreak is well controlled and less than 10cm as they said.
CHARACTERISTICS CREG three arms hydraulic jumbo drill is mainly dedicated to drill-and-blast mining, it can be also applied to geological investigation, fore-poling, fore-injection drilling, bolt drilling etc. This machine is equipped with advanced automation system, which can help operator to realize efficient and accurate drilling operation. The feedback from jobsite has proven a high reliability and adaptability. Especially the advanced computerized systems was very ‘’ergonomic’’, operator can easily understand this system through a short briefing (or a demonstration) about 15min. This system also has the following advantages:
- Reducing over break, case study shows reduction from 60 cm to 30 cm, or typical from 25% to 11% at 35 m² and 3 m each round;
- Reduced number of holes by 10-15 % due to accurate drilling and accurate distance in bottom of holes;
- Longer rounds possible due to more accurate drilling, increase from 3 to 4 meters is possible.
- Automatic drilling report as management of tool to optimize the drilling steel and drifter maintenance, parameter report can be used as an indication for anticipating the geology;
- Project integrated design and reporting system;
- Planning system.
- More navigation methods available (laser, profiler, total station);
- Could have more function according to custom’s need.