Gulf Construction Online - Twin dams work in full swing

Turkey

Sandvik CAPP bits power the Tamrock Ranger drilling rigs at the projects.

Turkey

Twin dams work in full swing

Equipment from Volvo and Sandvik is playing a major role in work on twin dams being built on the Coruh River in Turkey.

01 September 2002

WORK is well under way on a major twin-dam project in northeastern Turkey close to the Georgian border.

The project involves massive earthmoving operations involving 600,000 cu m of rock per month and this is providing a major role for a fleet of Volvo articulated haulers, excavators and wheel loaders; as well as a fleet of Tamrock drilling rigs equipped with Sandvik CAPP bits and drilling rods, which is being used by the joint venture contractor for drilling operations.

The Borcka and Muratli dams are situated on the Coruh River, 30 and 40 km from the city of Artvin respectively. The twin dams form part of an overall project which includes a total of seven hydro-electric dams and power plants on the Coruh river, which will supply power to the northeastern Black Sea region of Turkey.

Both dams are being constructed by a joint venture comprising Yuksel Construction, and Temelsu Construction from Turkey, along with Austria's Strabag.

On both projects, Yuksel Construction is responsible for drilling and blasting as well as earthmoving, and is using a total of eight Tamrock drilling rigs equipped with Sandvik rock drilling tools including CAPP bits. Seven of the rigs are using 76 mm and 89 mm diameter bits in conjunction with Sandvik T45 drilling rods, while an eighth unit is equipped with T51 rods.

Yuksel Construction is also relying on a fleet of Volvo articulated haulers, excavators and wheel loaders for the combined earthmoving operations.

Borcka Dam

The Borcka Dam and hydro-electric power plant is located 30 km from Artvin and construction began in 1999, with completion scheduled for 2005.

The dam's height will be 86 m, with a crest elevation of 189m, crest length of 557m and crest width of 10 m. The dam's construction involves 7.7million cu m of rock fill, as well as 580,000 cu m of concrete.

For the rock, a drilling, blasting and earthmoving operation is taking place. Rock is drilled, blasted and hauled from what will be the dam's 30-km-long reservoir and then deposited at the dam's rock fill face.

Four Tamrock Ranger 600 drilling rigs equipped with Sandvik drilling tools are operating at the Borcka project. Drilling to a depth of 15 m, with approximate 150 cm spacings, the rigs drill 100/150 holes before blasting takes place.

The rock is volcanic and very hard, and consequently Yuksel has been pleased with the performance and longevity of the Sandvik bits. According to a site spokesman, the bits are averaging 4,000 m before they need to be changed, while the Sandvik rods are averaging nearly 3,000 m.

The drill rigs work approximately 10 hours a day, which equates to nearly seven hours drilling time. Blasting at Borcka takes place every day.

Excavators equipped with hydraulic hammers, including two Volvo EC210 units, break up the rock into smaller pieces.

The 21-tonne Volvo EC210 has a 7.16 tonne lifting capacity at 6 m ground level reach, 171.7 kN breakout force and 166.8 kN tearout force.

The rock is loaded onto the site's hauling fleet which transports it 1 km to the dam's rock fill area. At the Borcka site, four Volvo wheel loaders are in operation loading trucks, three L150Cs and one L180C unit.

The Volvo L150C has a bucket capacity of 12 cu m and a breakout force of 192.7 kN, while the larger Volvo L180C wheel loader has a bucket capacity of 14 cu m and a breakout force of 211.5 kN.

Yuksel has 25 trucks working on the project along with a total of 10 Volvo A35C 6x6 articulated haulers.

The Volvo haulers are needed because some of the rock deposits are only accessible on steep and muddy tracks. Working approximately eight hours a day, the Volvo A35C haulers are significantly aiding a 400,000 cu m a month earthmoving operation at the Borcka Dam.

With their 12-litre engines, the Volvo articulated haulers are described a s extremely powerful machines that can handle the toughest conditions. The roads in and around the Borcka Dam demand a hauler that is well suited to steep uphill climbs, as many of the roads are unsuitable for conventional trucks, says a spokesman for the Sweden-based Volvo Construction Equipment (VCE).

The A35C has top speed of 52.3km/hr, a volume of 14.8 cu m struck and 19 cu m heaped, and a payload capacity of 32tonnes.

The dam will be equipped with four radial spillway gates, with a discharge capacity of 10.639 cu m/sec. It will have two diversion tunnels each with a length of 350 m, while the power plant will feature two 150 MW turbines.

Muratli Dam

Located 10 km further upstream, the Muratli Dam and hydroelectric power plant is situated on the Turkish side of the Georgian border, in what was a military zone during the Cold War era.

This project also began in 1999 and is scheduled for completion by 2005.

The dam will have a height of 44 m, a crest elevation of 100 m, a crest length of 438 m and a crest width of 10 m. Here the construction process requires 1.9 million cu m of rock fill and 417,770 cu m of concrete.

Rock is drilled and blasted from what will be the dam's reservoir and hauled the approximate 2 km to the rock fill site.

Because access to and from the drilling rigs is less arduous, the contractor has not needed to use any Volvo haulers on this site, but two Volvo wheel loaders are in operation.

Two Volvo L180C wheel loaders are loading trucks at the rock face at Muratli. Working eight hours a day they are contributing to a 200,000 cu m a month earthmoving operation.

One Tamrock Ranger 600 and a Tamrock 1100 drill rig are currently operating on the Muratli Dam site. Both units are equipped with Sandvik 76 mm and 89 mm CAPP bits; the Ranger 600 using Sandvik T45 rods and the larger Tamrock 1100 being equipped with Sandvik T51 rods.

Drilling to a depth of 15m with 150cm spacings, the rigs work seven hours a day drilling 100/150 holes before blasting takes place.

The Muratli Dam and hydro-electric power plant will have four radial spillway gates with a discharge capacity of 10.961 cu m/sec. Two 350-m-long diversion tunnels are currently under construction, while the power plant will be equipped with two 57.5 MW turbines.

As the Muratli area was a military zone access to the site has had to be improved. Originally only a single track road existed to the site, and this 20-km-long road is currently being widened so as to improve access and allow heavy equipment to be delivered.

Two Tamrock Ranger 600 drilling rigs also running with Sandvik drilling tools are currently operating on the mountainous Muratli road. Blasting occurs along the highway at least twice a day, with the Sandvik-equipped rigs drilling holes vertically and horizontally to a depth of 6 m.