Andorra Completes Service Tunnel at Dos ValiresThe 2,870 m-long Dos Valires service tunnel broke through in the Principality of Andorra. The first blast took place on 19th October, 2005 and the last blast on 20th April, 2007. The tunnel has been drilled and blasted, while initially it was envisaged to bore it by means of a TBM. A Tamrock Axera D6 jumbo equipped with 4.3 m feeds, one of which is extensible, has been used to drill the blast holes and for bolting. At the beginning, Nagolita explosives were used but subsequently, when the excavated length began to be substantial, Goma-2 ECO explosives supplied by Maxam was preferred to avoid ventilation problems. Visit www.miningandconstruction.sandvik.com and www.maxam-corp.comMuckers included an Atlas Copco Scooptram ST1030 front end loader and a ST6 for ancillary tasks. Click here. Mucking-out was performed from the face of the service tunnel to the cross-passages connecting with the main tunnels each 240 metres. From the main tunnels to outside, the fleet of muckers employed in the main tunnels took over, i.e. a CAT 962 and Volvos A25. Visit www.atlascopcowagner.com, www.cat.com and www.volvo.comBASF Construction Chemicals has collaborated from the start in the design and implementation of shotcreting to support the tunnels and supplied the following admixtures: super plasticizer Rheobuild 1000 EPS, liquid precipitated silica Meyco MS 685 and alkali-free accelerator Meyco LTD 172. A Putzmeister WKM 102 shotcreting robot sprayed the concrete, backed by a Variomec concrete mixer of Normet. Visit www.basf.com, www.putzmeister.es and www.normet.fi Cifa formwork systems at the Dos Valires tunnel The Dos Valires tunnel, a twin-tube link with a service tunnel between the two bores, could only be driven from the east portal since there was no access at all from the west. On 20th April when the service tunnel broke through, crews still had 195 metres to bore in the south tunnel and 260 metres in the north tunnel.The machinery used in the main, south tunnel is an Atlas Copco Boomer 353, equipped with 4.9 m feeds, a Putzmeister WKM 102 shotcreting robot then replaced by a Meyco Potenza and a Normet Himec 9910 platform for the loading of explosives and placement of bolts while in the north tunnel, the machines are a Tamrock Axera T11 jumbo with 4.9 m feeds, a Putzmeister WKM 102 then replaced by a Meyco Potenza and another platform Normet Himec 9910. The explosives are Nagolita and Goma-2 ECO, Primadet detonators, with mechanised loads. Visit www.atlascopco.com or www.boomer-rig.com and www.meyco.basf.com/Meyco/ENMucking-out in both tubes is performed by a CAT 962 loader and 4x4 and 6x6 articulated Volvos A25. For cleaning the faces, a Case CX210 excavator is used. Visit www.casece.comFor ancillary tasks (ventilation, cables, etc.), a Normet Himec 9810 manlift and a Manitou MRT 1650 platform are used. Cifa carriages are under assembly for formwork concrete. Concreting of the invert has already began. Visit www.cifa.com. Click here and ad/13.