Last weekend another shipment of the giant steel pipe components for the penstock arrived in Eskifjörður fjord. The pipes measure 3 metres in diameter, are 9 metres long and weigh 45 tonnes.

Delegates from the 10th annual aluminium conference held on the 12th – 14th of June in Reykjavík travelled east for a visit to the Kárahnjúkar construction site as well as the construction site of the aluminium smelter in Reyðarfjörður.

Workers from Icelandic contractor Suðurverk have returned to Kárahnjúkar and are getting ready to start off where they had to stop last fall when winter arrived, but the contractor is in charge of building the Desjarár dam, and Sauðárdals dam.

Italian contractor Impregilo has fitted the eating facilities of the TBMs to be used as rescue pods in case of an emergency. If need arises, for instance if a fire would erupt in the tunnel behind the TBM and exit from the tunnel would be impossible, the TBM operators will be able to stay put and use oxygen masks to guard themselves from smoke or perilous gasses.

A certain milestone was reached last week when the first spiral case was installed inside Valþjófsstaðarfjall mountain.

Icelandic contractor Arnarfell has finished blasting and digging a quarter of the Ufsarlón headrace tunnel or some 900 metres of the total 3500 metres.

The spiral case which surrounds the turbine runner for the first machine unit of six in the powerhouse was moved into the cavern inside Valþjófsstaðarfjall in week 21.

The TBMs are still struggling in difficult conditions as is evident in the progress figures fir week 20.

Last Thursday saw the completion of the toe wall of the Kárahnjúkar main dam.

The main dam at Kárahnjúkar is taking shape and some 115.000 cubic metres were added last week, so all in all some 40 percent of the filling material is in place.

The three TBMs are still showing unequal progress as TBM 1 is moving at a good pace, but the others are progressing slower.

Two Impregilo employees were taken to hospital in Reykjavík after suffering injuries at the toe wall at Káranjúkar dam last Monday.

Tunnelling and Trenchless Construction, the world´s leading underground construction publication has named Italian firm Impregilo “Contractor of the year 2005” for its role in the Kárahnjúkar Hydroelectric Project.

Pipe components for the penstock at the Kárahnjúkar hydroelectric plant are being transported from shipside in Reyðarfjörður fjord, to Fljótsdalur valley, where workers from Slippstöðin, a contractor from Akureyri will start installing them in June.

TBM 1 made good progress in week 17 but the other two made little headway due to unfavourable conditions and necessary maintenance.

Experts from many diverse fields serve as consultants on all matters regarding the Kárahnjúkar hydroelectric project. They have, among other things made recommendations concerning the design of the various structures on site.

Representatives from Landsvirkjun and Icelandic contractor Fosskraft have signed a contract regarding the construction of the entrance building in Fljótsdalur valley. Fosskraft´s bid was the lowest for the project.

Work goes on at both ends of the headrace tunnel from Ufsarlón pond and the tunnel now measures some 600 metres and most of the work has benn done at one end. Blasting at the other end started this week.

The design process regarding the spillway of the Kárahnjúkar dam is well underway with final tests using a model of the Hálslón reservoir and the Hafrahvammaglúfur canyon being conducted by professors and doctoral students at the Swiss Federal Institute of Technology Zurich, who built the model in cooperation with Icelandic engineering firm VST and Swiss company Electrowatt-Ekono.

There are 1300 employees working at the Kárahnjúkar site at this time, 270 of those coming from China. The employment figure is expected to rise to 1600 during the Summer, according to Friðrik Sophusson, managing director of Landsvirkjun at the company’s annual consultation meeting last week.

Landsvirkjun advisors say that the original design criteria for the dams at Kárahnjúkar are still valid in all major aspects despite the recent re-evaluation in view of further geological data.

Impregilo workers have begun cement work on the part of the headrace tunnel that connects to the Hálslón reservoir and also in the bypass tunnel underneath the Kárahnjúkar dam.

Tunnel boring machine number 2 shifted into high gear after having made little progress in the past weeks. The machine drilled over 220 metres which can be considered quite an achievement.

Things moved at a slow pace in the 12th week as the figures below show. The three TBMs drilled only 70 metres between them, mainly due to delays caused by reinforcement operations.

Landsvirkjun has awarded the contract of constructing the entrance building in Fljótsdalur valley to Icelandic contractor Fosskraft JV. With a bid of 349 million Icelandic kronur(appr. 4,5 million euros), a figure amounting to about 70% of the cost estimate, Fosskraft was the lowest of all contractors bidding for the project.

Two draft tubes of the total six intended are now in place in the powerhouse cavern in Fljótsdalur valley as can be seen in the accompanying picture.

Instabilities in the excavation face and water inflow delayed the two TBMs in operation last week.

The Ufsarlón pond headrace tunnel has reached 410 metres in lenght. Workers from Icelandic contractor Arnarfell added around 40 metres to the tunnel last week and the operation is progressing at a good rate.

The first draft tube of six has been put in place inside the powerhouse cavern as can be seen in the picture on the right. The piece, weighing just over 9 tonnes has been set in its right place where it will be cemented down.

Progress for TBMs 1 and 3 was slow last week mainly due to unfavorable rock conditions and the amount of time spent reinforcing the tunnels.

The headrace tunnel from the forthcoming Ufsarlón pond has reached 350 metres in length. The contractor is making good progress and the rock conditions have been favorable for digging.

An Icelandic contractor, Keflavíkurverktakar, has started working on the foundation for the switchgear house in Fljótsdalur valley at the entrance to the cable tunnel that leads to the transformer hall inside the mountain.

The main project this week in the powerhouse cavern was the preparation for the installation of the first draft tube of the six intended.

On Tuesday, two draft tubes were transported into the powerhouse cavern arriving right on schedule making this turning point even more pleasing. The draft tubes will be placed in a pitfall where they will be cemented in and then the turbines will be placed on top.

The three tunnel boring machines (TBM) have at this point in time drilled a total of 13.1 kilometres, a length measuring 27% of the total length of the headrace tunnel.

A sudden change in weather conditions made it possible to resume transport of filling material to the main dam site after a delay lasting for a few weeks. While adding only 3000 square metres to the fill, people are optimistic for progress being made in February although it does depend on the weather.

The three TBMs have now completed just over a quarter of the total length of drilled tunnels at the project site. 12,3 kilometres of the 48, 3 kilometres, or 26 percent have been completed.

Progress in the first week of the year was, on the whole good, with some machines doing well and others not so.

TBM 2 has been making great strides, so to speak and is one upping itself week after week. In the first week of the year it travelled 250 metres and last week it made a progress of over 270 metres which has to be considered as quite a good an achievement.