The Hugo North, Hugo South, and Heruga orebodies are planned to be mined by underground panel caving methods. The first underground orebody to be mined is Hugo North, where two mining lifts are planned.

The Hugo North Lift #1 lateral development advance recommenced in July 2016. The first drawbell milestone is currently scheduled in May 2022, and sustainable production in January 2023.

Ore will be extracted by load-haul-dump (LHD) machines from drawpoints and trammed to centrally located orepasses, which will transfer the material down to the truck haulage level below. Trucks will haul the ore to one of two off-footprint gyratory crushers. During the ramp up to 30,000 t/d production, between 2022 and 2024, crushed ore will be conveyed to storage bins at Shaft #2, where the rock will be loaded into skips and hoisted to the surface. Post 2024, following commissioning of the conveyor to surface, crushed material will be transferred by incline conveyors from crushers to the surface run-of-mine (ROM) stockpile; the Shaft #2 ore hoist will provide backup capacity during maintenance of the conveyor-to-surface system.

Underground primary crusher and Conveyer system from Primary crusher to Shaft#2 are successfully installed. In addition, the conveyer to surface development is 79% complete. Shaft #3 and Shaft #4 sinking is ongoing.

The impact of the Covid-19 pandemic on the Oyu Tolgoi underground mining operation and the geotechnical conditions of Hugo North Lift #1 are adversely affecting the project schedule and capital costs. In this regard, Erdenes Oyu Tolgoi LLC and the Government of Mongolia are working to improve mine operations, financing and contracting.