Safety and teamwork drive OT underground milestone

Commitment to safety and teamwork has helped our Thiess team contribute to a significant milestone at the Oyu Tolgoi (OT) Boxcut and Decline Project in Mongolia.


The team, in joint venture with local contractor Khishig Arvin Industrial, achieved the final breakthrough in the conveyor decline tunnel, connecting the C2S conveyor to surface tunnel to the existing OT underground mine on 16 August.
Watch the celebration video.

It’s an important achievement for team. The C2S system is critical to the OT project, serving as the main access to the OT underground mine and enabling the transportation of ore from underground to the surface. Once complete, it will enable production capacity to increase from 25,000 tons of ore per day (using a hoisting system) to approximately 95,000 tons of ore per day. 
Team effort 

Executive Director Mongolia Leon Coetzer congratulated the Thiess team for their efforts during a challenging year. 

"It has been a hard journey, and it took immense effort from all of you to pull this off. There have been many great moments and achievements along this path, not the least the fact that it was done from start to finish with no LTIs (Lost Time Injuries). Seen in the light of COVID-19, often very poor ground conditions, and the other issues particular to the project, this is a result that will not be easily repeated by others." 

Overcoming challenges 

Underground Superintendent, Batbayar Batsukh, praised the team’s efforts to overcome many of challenges of underground excavation, from rock properties to technological difficulties. 

“We have successfully implemented an initiative to accelerate the speed of the Conveyor decline by about 300m ahead of the service decline and provide additional access faces,” Batbayar said. 

“As a result, the mining rate increased by 23 per cent which was an important aspect to completing the work on time,” he said. 

Everyone safe everyday 

HSET Manager, Tuya Gerel, said the commitment of the project’s 240 employees to safety helped ensure their success.  

"Safety is our utmost priority - we worked for 1829 days or 3-million-man hours LTI free during the project under the motto ONE TEAM, ONE DREAM.” 
 
C2S Call Outs 

The C2S decline is by industry standard a very steep decline. Completing this project safely and efficiently is a remarkable achievement. 

- The average advance per blast of the project is 5.6m
- December 2019 was the best performing month as the team completed 377m. In 2020, a total of 3930m development was completed - the best annual mining rate.
- Since the project began, a total of 3,165 blasts have been safely completed. 

C2S Firsts 

- The first eDev® electronic detonators at Oyu Tolgoi was successfully trialled and implemented into the operation. These enabled the team to control vibrations during blasting, minimise over-break and optimise the blast timing for rock fragmentation and cast distance while blasting large tunnel faces  
- The C2S team are now experienced in long resin encapsulated cable bolting (up to 10m) using an automated resin injection system mounted on a Jumbo Drill rig. The resin cures and sets within seven minutes, significantly decreasing cycle times.