Shafts' Sinking Complex for Potassium Chloride Mining and Processing Plant
Shafts' Sinking Complex for Potassium Chloride Mining and Processing Plant Koca Group was awarded with construction contract for 2 complexes of shafts' sinking with 6.5 m inner diameters reaching to 364 m and 332 m depths for the large deep potassium mining project in Turkmenistan with capacity 1.4 million tons, managed by the state owned company of Belarus JSC “Belgorkhimprom”.
The scope shall cover the design and construction on turnkey basis. The design of the structure shall be simulated to see the earthquake behavior. Concrete mix design shall be made for extreme environmental conditions to provide sulfate resistance and high performance for a service life over 100 years as per European Norms using special mineral addition in concrete.
The depth of water bearing zone where the Shafts shall be constructed changes from 75.0 m to 95.0 meters and deep jet grouted collar method for the purpose creating a circular water barrier around the shaft is used which is the patented technology of the company. The Proposed Method was accepted by the Client as an alternative to Freezing Method.
Due to very different ground conditions, shotcreeting with and without reinforcement, face stabilization with rock anchorage, excavation in soft ground, in clay drilling and blasting, cement slurry injection, application of liquid membrane on shotcreeted excavation face, dewatering and contact injection behind the reinforced concrete shaft wall will be used during shaft construction.
Permeability coefficient of concrete was very important considering the very aggressive environment to have impermeable concrete; micro silica is used in concrete mix design. Test for water penetration depths done according to DIN1048-2 with 700 Kpa pressure at the laboratory of one of the leading technical university showed that concrete could be assumed as totally impermeable.
- 1.4 mln tones of standard 95% potassium chloride per annum, including:
- 0.6 mln tones per annum – granular KCl;
- 0.8 mln tones – fine-grained KCl .
Ore – the qualitative composition of ore reserves not less than 45 years.
On the working platform, a system of working outputs of pit bottom that is necessary for the compliance with the input of design capacity and further mine operation is constructed. The structure has central underground substation; garage; electric shop; fuel and lubricant, explosive materials and equipment warehouses; medical center and etc.