Groove Making in a Tubing Lining Elements

Tubing lining is used as the final lining of shafts sunk in extreme hydrogeological conditions, and it is composed of a cylinder made of separate rings. Individual rings are composed of separate, equal segments called tubings. Tubings can be made of reinforced concrete, cast iron and steel. Steel tubings, having dimensions depending on the shaft diameter, have the form of a metal pipe [1-4]. Despite of high durability of the tubing lining, damages of the lining in form of leakages, scratches and fractures can occur. The most common causes of these damages are material faults and hydro-geological conditions [4-9]. The damages of the tubing lining are direct danger for the shaft operation because they are usually a cause for a water inflow to the shaft. The safety of mining excavations is considered dangerous, because the devastation of the lining usually comprises a bigger zone, and the possibility of more intensive water leakage related with rock mass movements is quite realistic [5,7,10]. Different methods of tubing lining repair and protection were invented and used over the years. All of them comprise of some kind of the reinforcement of the damage to seal the tubing lining. For the purpose of efficient and safe sealing of the tubing lining, PBSz S.A. uses a sealing method by making a closed circumference groove around the sealed area in the internal shaft wall, whereas the groove depth must be smaller than the tubing depth. Then the sealing element is placed in the groove and pressed with spatial insert closed in the top side and having a hole for the injection of the sealing medium. In the next stage, the insert is mounted to the lining and then the sealing medium is injected in. When the process is finished, the insert hole is closed. A specially designed milling machine is used for making grooves in shaft tubing lining. The milling machine is composed of the power transmission system and a construction for tubing and advance mechanism mounting. A battery drill-driver is used as the milling machine driving system, and the whole device is mounted to the tubing with the use of specially designed guides with handles. A model and a photograph of the tubing milling machine is shown in Figure 1.

Figure 1: A model and a view of the tubing milling machine.

Figure 2: Milling machine construction; 1-main plate with mandrel and threaded sleeve; 2-milling head; 3-worm gear, 4-hub with guides and mounting device, 5-mounting to main plate device, 6-guides with mounting-depending on the chosen option: •round for mounting milling machine with handles, •rectangular for mounting the milling machine with handles; 7-planetary gear with driving system housing.

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