PJSC North Ore Mining and Processing Plant (SEVGOK)

SVITEKS is constructing an underground part of cyclic-and-соntinuous technology in Pervomaisk open pit of North Ore Mining and Processing Plant. Totally, the company will mine out more than 43 thousand cu m, the biggest part of with is inclined shafts for LК-1, LК-2, LК-3 and LК-4 conveyers with cross - section of 21,6 sq.m. The works are carried out by drill and blasting method using self-propelled machines.

Face drilling of inclined shaft is provided by Boomer-282 drilling rig with 2 perforators. The diameter of blast holes is 45 mm, the length is 2, 5 m, a number of blast holes for the face is 92 units. The cleaning of mined rock is carried out by ST-1030 loading machines with 10 ton- loading capacity. To prevent wheels slipping of drilling rig by reason of large angles of shaft inclination (15-16), the wheels are fitted with chains. Installation of the roadway is performed using steel arch support SVP-27, the width of which is 0,5-1 m, followed by grouting, the width of the grout is 250 mm. Grouting is carried out using BN-1 grouting pumps. For the purpose of damp – proofing of the roadway, filling of cavities by grout mixture between support and mined rock is carried out.

The following Atlas Copco facilities are used while performing mining roadway:

-                        Boomer – 282 self-propelled drill rig – 2 units;

-                        ST – 1030 loading machine – 2 units;

-                        BN- 1 pump concrete machine – 2 units;

-                        Unigrout Miniflex grouting pump – 1 unit;

-                        Dalgakiran compressors – 75 – 5 units.

A unique mining of 2 inclined shaft sections, each of which for 100 m is being carried out by special method on fills under working railway lines. “Spanish umbrella” was taken as a special method when protective pipe shields 89 mm in diametr and 15 m in length are drilled followed by grouting.

Concrete lining in the face of tunnel is carried out before drilling a pipe shield. After that, wells marking and wells drilling are made by reequipped drill rig Boomer – 282, Symetrix system, produced by Atlas Copco. The key point of drilling is that an advance bore bit on rock bolts pickups starting pipe 89 mm in diameter and 3 m in length with its own drilling bit and holes for grouting. After drilling the first 3 m, rock bolts with bore bit are pulled, the second core-shell, rock bolt are screwed on and drilling process goes on with 6-meter standing pi

An advance of next pipes and rock bolts up to 15 m is carried out in a similar way. A drilling standing pipe is pulled after drilling process but a core-shell with holing remains 15 m in length in the solid mass. Thereby, 48 core-shells 89 mm in diameter and 15 m in length are bored and set up at the contour of the face in the direction of the future roadway. Thereafter, a gradual grouting of bulk rock solid mass is made pumping a grout into core-shell holes by grouting pump Unigrout Mininflex -11. Grouting is to be made as long as holes continue receive a grout.

When the grout absorption by all wells ends up, the grouting stops. As a consequence, we have got a steady protective shield, which has a sufficient rigidity owing to steel core-shells and concrete that was produced after grout absorption by rocks. After installation of the shield, a working of rocks in the face of inclined shaft is carried out under the protective shield. Roadway lining is performed by steel support and concrete using hydraulic breaker, rock-drills and sometimes performing blasting operations.

 
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