Irtyshsky is an operating underground mine exploiting a polymetallic volcanogenic massive sulphide (VMS) deposit of average size and grade. The mineralisation is of lenses with extensive strike extents but more limited down-dip persistence. There are three principal ore bodies: Main, South East, No 2.

Irtyshsky Principal Orebodies:
Main:
- Orebody Strike length - 2,500 m;
- Down-dip length - 750 m;
- Thickness - 3.5 m.
South East:
- Orebody Strike length - 3,000 m;
- Down-dip length - 400 m;
- Thickness - 2.7 m.
No 2:
- Orebody Strike length - 1,600 m;
- Down-dip length - 300 m;
- Thickness - 1.35 m.

The orebodies pitch slightly to the NW with their long axes roughly parallel. The average strike of the Irtyshsky ore body is NW-SE and the dip of the ore body is steep to sub- vertical (70-80°). The ore body is gently folded with secondary thickening of the ore lenses in the fold axes. The copper and zinc grades increase with increasing depth from surface. Most mining is currently taking place in the lower parts of the Main (12 and 13 levels) and SE (11 level) orebodies. The No 2 Orebody is not being mined at the present time.

Labour intensive shrinkage stoping is used with high ore dilution (32%). Some sublevel caving and room and pillar mining is also conducted. Jackleg drills and slushers are used for mining with rail haulage to the ore pass leading to a jaw crusher. Hoisting in a 650 m deep shaft is conducted with 10 t skips.

Ore is received in the feed storage building and tipped intj the primary crusher and reduced down to less than 300mm. Crushed ore is fed separately to two SAG mill, 7 m by 2.3 m with a design capacity of 95 tph, actual thoughput of 100 tph and the maximum capacity is130 tph. The increase in capacity to the design capacity was achieved by the introduction of rubber liners to the mill and the addition 100 mm steel balls.

Each SAG mill feeds two ball mills (3.6 by 4 m) which are in series with closed circuit classification cyclones. Output from the secondary ball mills is fed to a common tertiary ball mill (4.5 by 5 m) in closed circuit with cyclones. Cyclone overflow is fed to the copper flotation circuit.

Ore from the Irtyshsky mine now processed at the Nikolayevsky concentrator, also improved operational efficiency.

The copper flotation is a four-stage process, involving rougher and three stages of cleaning. There is some regrinding in another ball mill after the first flotation. Various float products of different grades report to the copper concentrate stream while the tailings from the rougher stage report to the zinc circuit. Cell sizes range from 2.5 to 3.2 m3.

The thickened copper concentrate slurry is pumped to a series of vacuum filters and from there dried in a direct heated rotary kiln. The dewatered concentrate is stored in bins for loading into rail wagons to be transported to the Balkhash smelter. The zinc-pyrite concentrate is thickened, filtered and stored for transport to the Kazak Zinc smelter.

The feed is sampled at the overflow of the grinding sections, the tailings at the end of the rougher banks and the final concentrate at the fe ........