“The issue of waterproofing cast iron tubing is one of the most important in mine construction. It is interesting to note that the German engineer Rimmer proposed the method of minting a lead gasket, which is still widely used today, in 1883. This technology is rather laborious and has disadvantages: low mechanical strength of lead with its high creep. Numerous studies have established that the lead gasket prevents water seepage only in the embossing zone, it is only 25-30 mm from the inner edge of the tubing, while the rest of the gasket width does not perform a waterproofing function, ” - Anatoly Mishedchenko, leading engineer of the mining department at MCC Shaftproject company, explains.
The specialists of MCC Shaftproject LLC, based on the world experience of using waterproofing profiles made of ethylene-propylene rubber (EPDM) in the construction of transport tunnels and subways, suggested using this material for waterproofing mine-tubing lining. EPDM profiles have high ozone, oxygen, heat resistance, resistance to aggressive environments. Rubbers based on them can be used at temperatures below -50 С. This is extremely important when sinking shafts in low-temperature freezing, as well as when working in permafrost conditions.
“To use the EPDM profile for waterproofing the tubing lining, it is necessary to make a groove in each tubing along the contour of the backrest for the seat to fit the tightness of the waterproofing profile.
For additional safety and "maintainability" a groove is provided for the internal night work with a wire ", - the first deputy General Director of MCC “Shaftproject" Evgeniy Kolontaevskiy specifies.
The proposed construction of waterproofing of tubing lining is technologically more applicable in the mechanized method of sinking mineshafts. It allows reducing the time of installation and waterproofing of tubing lining. And this, in turn, contributes to an increase in the rate of penetration.
We conducted bench tests of the waterproofing profile for a water pressure of up to 6 MPa (corresponds to a depth of 600 m) in December 2019. The profile's performance has been confirmed at a hydrostatic pressure of 6.5 MPa,” - Evgeniy Kosenko, deputy head of the mining department says.
According to the authors' calculations, for a mine shaft with a depth of 740 m and a diameter of 8 m, only by replacing lead gaskets with EPDM profiles, material savings of 19.3 million rubles will occur; reduction of the time required for the erection of the support - by 34%; reduction in the operation of machines and mechanisms (costs of pneumatic tools) - by 11%.