The geological history of the southern part of Mongolia is characterized by the continental accretion and Basin-and-Range style crustal extension, followed by regional-scale compressional folding and faulting. Elongated, east-west trending mountain ranges and intervening basins are therefore widely present in the region. Those structures are dominatly composed of Late Cretaceous to Permian-aged sedimentary sequences, overlain by Quaternary unconsolidated sediments. Mountain ranges between the basins comprise crystalline basement rocks dominated by intermediate to high angle faults that show evidence for both compressional and extensional movement. The most prominent structure in relation to the Ovoot Tolgoi Deposit is the arcuate, east-west-trending, moderately-dipping Nariin Sukhait fault where the Late Permian coal-bearing sequences are exposed.

The Ovoot Tolgoi Coal Mine, which comprises of the Sunset Coalfield in the west and the Sunrise Coalfield in the east, is one of the three operating coal mines in the region of Nariin Sukhait.

The current geological understanding of the deposit has organized the coal seams into a number of Seam Groups including the Seam Nos. 4, 5L, 5U, 6, 7, 8, 9, 10 and 11. Each of the Seam Groups are further divided into a number of sub-layers or known as plies based on parting material within the Seam Groups.

The overall estimated thickness of the coal-bearing sedimentary sequence is 1,370 m with a cumulative th ........

The mining method employed at the Ovoot Tolgoi deposit could be described as open pit terrace mining utilising large scale hydraulic excavators and shovels and trucks. Terrace mining is utilised where coal seams dip steeply and operating machinery on the coal seam roof and floor is not possible, due to the steep seam dips. Terraces, or benches, are excavated along fixed horizontal horizons and these benches intersect both coal and waste. Coal and waste are mined separately on each bench with dozers being used, as needed, to push coal or waste down to the excavator for loading onto trucks. This mining method allows large scale open pit mining to occur productively in steeply dipping coal seam environments. All waste is dumped ex-pit, as the steep dips preclude in-pit dumping.

The Ovoot Tolgoi Coal Mine started production in 2008 in the Sunset Pit and then in 2011 in the Sunrise Pit. Subsequently, SGS commissioned an updated PFS in 2012 to address an increased production target. In general, the current operation is engaging the mining method of an open pit terrace truck-and-shovel mining, where coal seams dip steeply and operating machinery on the coal seam roof and floor is not possible, due to the steep seam dips. Terraces, or benches, are excavated along fixed horizontal horizons and these benches intersect both coal and waste. Coal and waste are mined separately on each bench with dozers, as needed, to push coal or waste down to the excavator for loading onto hau ........

- subscription is required.

- subscription is required.

- subscription is required.