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 delivered by truck 70 km to the Berezovsky Concentrator and the concentrates are railed to Balkhash Smelter.

There are two crushing sections which are each fed at 40 to 42 tph. Ft the time of visit one section operational. Primary crushing is undertaken underground with two stages of crushing on the surface. The primary mill size is 2.7 m by 3.6 m whilst the secondary, tertiary and regrind mills are each 2.1 m by 3.0 m.

Following crushing, the ore is fed to three stages of ball milling. The first stage is in close circuit with a spiral classifier, the second and third stages are in closed circuit with hydrocyclones. Overflow from the tertiary ball mill cyclones is fed to the flotation circuit. The regrind mill in the flotation circuit is currently not in use as the nature of the ore has changed and there are fewer impurities than previously.

Flotation of copper consists of rougher stage followed by three cleaner stages. Zinc flotation follows a s ........