Rudarski radovi br 4 2011 - Institut za rudarstvo i metalurgiju Bor

For relocation the Krivelj River flow<br />
in the zone of Field 2, construction of a<br />
tunnel, inside diameter D = 3.0 m, length<br />
L = 2 450 m, is anticipated. The tunnel is<br />
built in the hilly mass of right bank, Figure<br />
4. The most difficult section for construction,<br />
about 300 m in length, is on a<br />
tunnel part that has to be performed under<br />
the foundation of Dam 2 to about 10 m<br />
below the rock level in the river bed. This<br />
section will be, if necessary, performed<br />
with the previous consolidation of field in<br />
the zone around planned excavation.<br />
Development of a tunnel in the rock<br />
mass under the valley sides, and at elevations<br />
contained in the level of the Krivelj<br />
River bed (andesites, conglomerates and<br />
sandstones, sandstones and marls) was not<br />
a significant technical problem, and therefore<br />
it should not be expected any special<br />
difficulties in a tunnel construction which<br />
will be made a permanent deviation of the<br />
Krivelj River in the remaining part of this<br />
section. After construction of tunnel on<br />
this section, the collector will be sealed.<br />
For relocation the Krivelj River flow<br />
in the zone of Field 3, construction of a<br />
tunnel, inside diameter D = 3.0 m, length<br />
L = 1 700 m, is anticipated. The tunnel is<br />
built in the hilly mass of left bank, Figure<br />
4. The tunnel lining thickness is d = 25 cm<br />
and made of reinforced concrete MB 20,<br />
two-sides reinforced.<br />
For connection of the existing tunnel,<br />
for the Bor River, that is the introduction<br />
of water from the Bor River basin and<br />
water from drainage adit, the reinforced<br />
concrete is designed collector, internal<br />
diameter D = 1.60 m and length L = 350<br />
m, is anticipated.<br />
The Saraka Stream collector introduces<br />
the water from the catchment area<br />
of the Saraka Stream into the Krivelj<br />
River tunnel. Collector structure is made<br />
of reinforced concrete MB30, two-sided<br />
reinforced. Internal surfaces are protected<br />
with anti-corrosive coatings. Dimensions<br />
of collector are:<br />
- diameter D = 1.8 m<br />
- wall thickness d = 45 cm.<br />
Tunnel construction for deviation the<br />
Krivelj River in the zone of Field 3 will<br />
substantially deteriorate the conditions<br />
from the point of zone size, affected by<br />
flooding with high water of the Krivelj<br />
River. Namely, it can be considered that<br />
upstream of Dam 4 in flooding wave, the<br />
flood wave will slow down, or the accumulation<br />
of about 27 m depth (in a case of<br />
10 000 annual high water), what would<br />
mean the flooding of all areas that are at<br />
elevations below 320 m elevation.<br />
The following existing mining facilities<br />
are situated in a possible flooding zone:<br />
- open pit,<br />
- transport system for waste, and<br />
- water intake with settling pond and<br />
pump station.<br />
To allow the regulated run of the<br />
Krivelj River during floods, it is necessary<br />
to form a large enough storage (retention)<br />
an area of approximately 6 x l0 6 m 3 at a<br />
suitable location in the Krivelj River valley<br />
upstream from Veliki Krivelj. The<br />
accumulation space would be formed with<br />
maximum water elevation of 371.0 m,<br />
what would require the construction of a<br />
dam, height of about 34, with a crown at<br />
elevation of 373.0 m.<br />
No 4, 2011. 62<br />
MINING ENGINEERING