Four 60,000 t bunkers 75 m-deep and 40 m-diameter designed by Kalliosuunnielu for Helsingin Energia under construction by jv of Lemminkainen and YIT for completion 2003, value $45 million. Visit www.yit.fi 21/01. Under the Salmisaari power plant, four underground coal silos, of about 400,000 cu m, an underground refrigeration plant, 3 km of tunnel and shafts will be excavated. The coal will be moved from the surface to underground, and office buildings will replace the coal store above ground. Excavation and ventilation of the four silos will be a challenge, each having a diameter of 40 m and a height of 70 m. Drill/blast method. The new Sandvik Extra drifter-tool system will be used with a T35 thread on the shank adapter and R35 thread on the bit. The effective feed length of the rods is 6.1 metres. As the T35 thread allows the use of Sandvik Extra T35 MF extension rods in injection drilling, there is no need for conversion couplings. The hole diameter in tunnelling is 51 mm, and 54 mm in injection drilling with Retrac drill bits. The silos will be excavated with a Tamrock crawler drillrig in either 64 mm or 76 mm hole diameter, with extension rods and guide tubes as well as drill bits from Sandvik. The contractors are Lemminkäinen and YIT Construction. Design by Helsinki Energy and Rockplan. Budget of €50.4 million. Excavation to be completed in March, 2003. Visit www.sandvik.com, www.lemminkainen.fi and www.yit.fi 12/02.Excavation of four silos nearly complete in granite/gneiss, installing 6 m-long x 25 mm-diameter grouted rebar rockbolts in roofs on 1.8 m grid with 100 mm steel fibre reinforced shotcrete covered with 20 mm unreinforced layer, and 5 m-long rebar in sides on 2.5 m grid with 50 mm reinforced shotcrete covered with 50 mm unreinforced layer. Roofs formed using Atlas Copco Rocket Boomer profiling rigs, and bulk excavation using trackdrills. 2,500 cu m/day excavation. 3.5 km of tunnels complete. High pressure grouting using microcement with plasticizer and grout aid carried out by Craelius Unigrout truck. More from janne.lehto@yit.fi 47/02.