The ATO (Altan Tsagaan Ovoo) is an epithermal gold and polymetallic deposit of transitional sulfides in breccia pipes in a Mesozoic continental rift zone.

Three mineralized pipes at ATO (Pipe 1, 2, and 4) have been emplaced into stratified rocks as young as presumably Early to Middle Jurassic. Pipe 4 is mainly concealed. Pipe 3 contains abundant pyrite, but no significant amounts of Au, Ag, Pb, and Zn. There is a strong Au anomaly in soil at TO, as well as other accompanying metals, particularly Pb. In the aeromagnetic field, only post-mineral young dikes have a prominent positive response; much weaker responses outline some ring-shaped features. ATO resides near the center of the latter. Sinter and silicified rocks are reflected as shallow resistivity anomalies, but broad clay and chlorite-altered rocks are characterized by low resistivity. The pipes coincide with chargeability anomalies that overall really are quite weak.

An upper zone of Au-Pb-ZnAg mineralized rock at Pipe 1 is approximately oval in shape and is about 320 m wide. Pipe 2 is elongate to the NE and is approximately 320 m by 160 m in maximum dimension. Pipe 4, which is completely concealed, also is elongate to the NE and is about 400 m by 200 m. The pipes taper slightly with depth and have a carrot-shaped configuration, narrowing gradually to depths of approximately 200 m.

The deepest hole into Pipe 1, inclined 60 degrees, is about 700 m. Silica cap rock has a variable thi ........

The ATO mine is an open-pit truck and shovel operation. The truck and shovel method provides reasonable cost benefits and selectivity for this type of deposit. Only open-pit mining methods are considered for mining at ATO.

Pit designs were created to use 5.0 meters benches for mining. Slope parameters were applied as up to 50-degree inter-ramp slope angles; up to 70 degree bench face angles. Ramps were designed to have a maximum centerline gradient of 10%. Design criteria accounts for 3.5 times the width of the truck for running room in areas using twoway traffic. For roads designed outside of the pit, and additional safety berm is accounted for in the road widths. The ultimate pit is separates 3 small mines. Based on a resource block size of 5 m by 5 m by 2.5 blocks, ore loss and dilution was assumed not more than 3% and 2%.

The waste dump is designed as a flat surface extending through the valley to the north. The dump height is not expected to exceed 10 m between the dumping crest to the underlying topography. Waste material is dumped against a berm on the dump face, and dozers are used to maintain the dumping face.

The waste dump has a total capacity of more than 20 million tons of the required 2,846 thousand tons of waste, though there is suitable space to expand the dump to the north or upward.

The final production schedule uses trucks and shovels as required to produce the ore to be fed into the process plant.

- subscription is required.

- subscription is required.