Employer: Ellatzite-Med AD

Designer and contractor: Geotechmin OOD

Project execution period: 2007 ~ 2009

Main data: Length – 880 m; cross section – 7 sq.m.

Description of the project:

The driving of the tunnel is performed by the classical drill-and-blast method. The drilling of the blast holes is done by a jack hammer type ПР-27Б. The loading of the broken rock mass is done by a bucket loader type ППН-1С and dump-cars type ВРО-1.7 cub.m. The material is transported by electric trucks type 4.5АРП and 8АМ. The ventilation is realized in a combined approach by fans type СВМ-6М and СВМ-5М. The temporary strengthening is done by BSP (bell-shaped profile) metal frames (21.5 kg/m) on hard tie and wooden headboards.

A hundred meters of preliminary injection-strengthening works are performed in the area under an old basin for rich solutions. 25-cm thick monolith concrete is used for the permanent lining. For certain sections injection-filling and splashed concrete works might be performed using anchors type ТФА (4 or 5 pieces in a row) and 10x10 metal mesh with diameter 5 mm.

In addition to the gallery, the following hydrotechnical facilities have been constructed:

• Drainage concrete ditch – 33 m
• Culvert with diameter 1,000 mm, with wing walls – 7 m
• Settling tank at the tunnel exit – 45 cub.m.
• Water pipe for the transportation of polluted waters to the drainage gallery (diameter 250 mm) – 190 m
• Concrete deviation facility
• Water pipe to the settling tank (diameter 250 mm) – 42 m