Driving underground progress in Georgia 10 May 2016

A fleet of Sandvik tunnelling jumbos is moving AGE Insaat closer to completion of more than 40km of underground excavation on the Shuakhevi Hydro Electric Project in Adjara, Georgia.

Lowering the Commando DC125R for blast hole drilling

The Turkish main contractor has excavated approximately 40km of tunnels and adits since 2014, placing great reliance on its ten Sandvik DD421-60C tunnelling jumbos. In order to boost blast hole drilling and bolting operations AGE Insaat recently acquired a Sandvik Commando DC125R, the first such rig to be used in Georgia. All the equipment has been fully supported by Sandvik Construction throughout the project duration; with the Turkey aftermarket team playing a proactive role in backing-up the client’s tunnelling operations.

Three main tunnels are integral to the project: the 5.8km Chirukhistsqali–Skhalta transfer tunnel, the 9.1km Skhalta–Didachara transfer tunnel, and the 17.8km Shuakhevi headrace and pressure tunnel.

The Sandvik tunnelling jumbos have proved essential on the project, but a new solution was required for shaft sinking and bolting. Following in-depth discussions and site visits to fully understand AGE İnsaat’s real requirements in these areas, the Sandvik Construction Turkey team recommended, and has now supplied, the first Commando DC125R in Georgia. The rig is now being used with Sandvik Alpha 330 rock tools, which have also been used to great effect by the DD421-60C tunnelling jumbos.

The hydraulic Commando DC125R, which is self-propelled on a four-wheel drive carrier, uses the latest in rock drilling technology to provide high rates of penetration. It is part of a range of surface top hammer drill rigs renowned for their exceptional reliability – a vital concern in the remote and harsh conditions experienced in Georgia. With excellent fuel economy and low operating costs, these diesel-powered, self-propelled drill rigs are designed not only to save money with every operation, but are fully equipped to provide operators with the highest levels of comfort and safety.

The Sandvik Commando DC125R

The Sandvik Alpha 330 rock tool system increases operational productivity through use of the stronger and more rigid R33 thread. To further improve rigidity, the Alpha 330 possesses a new guiding function located between the rod and bit-skirt immediately behind the thread. This means that the rod cross-section over the guide is now 36% larger at the rear of the connection, greatly improving the rigidity of the joint. After the bit-skirt, the rod cross-section increases to Hex-35 quickly, and smoothly, ensuring that the sturdy thread is well guided inside the bit-skirt, offering higher precision in collaring – even in the complex rock formations and uneven surfaces found in Georgia.

The US$417 million Shuakhevi HEPP hydropower project is a run-of-river plant, construction of which began in 2013. The completed facility is expected to be delivered on time and on budget later this year. Once completed, it will possess an operational capacity of 185 MW with an expected electricity output of 452 GWh, much of it for export to Turkey.