Grindex pumps bedrock for more trains
The project Ådalsbanan is currently one of the biggest railway projects in Sweden. The contractor Lemminkäinen Infra is contracted for several of the tunnels that are under construction through bedrock. Grindex pumps are used when drilling holes prior to blasting. That requires extremely durable pumps to handle supply water and large amounts of drill cuttings. A sedimentation system is used to separate the drill cuttings from the water. For the water transport Lemminkäinen uses over 160 Grindex pumps from the sizes of Minor (6 hp) and Maxi (44 hp).
Background
The $945M Ådalsbanan project stretches as far as 81 miles, from the city of Sundsvall to the connection to the Bothnia Line railway. A renovation is necessary to connect the railway traffic between Southern and Northern Sweden, but also to enhance the train capacity from 8-10 trains per day to 50-60 trains per day. The project is scheduled to be completed during 2011.
Ådalsbanan will have eight new tunnels with a total length of 8.7 miles, straight through the Swedish bedrock. One of the contractors is Lemminkäinen Infra; they are one of the contractors for the construction of the 2.24 miles long Bjässholmstunneln, the 2.8 miles Kroksbergstunneln and Utansjötunneln. The length of two first tunnels takes them to the top ten-list of long tunnels in Sweden.
Grindex solution
Before each blast, Lemminkäinen are drilling some 160 holes for the explosives. Each hole is 20 ft deep and holds a diameter of 2.6 inch. The drilling operation requires large amounts of water, up to 15,900 gallons between each blast. By completion of the entire project a total of some 37 million gallons of water has been used. All this water needs to be pumped to the drill rigs and then dewatered, an operation that demands a reliable system with robust pumps. It is estimated that 10% of the suspended drill cuttings will reach the dewatering pumps. This means more than 1,700 lbs of drill cuttings needs to be transported between each blast.
By completion of the project a total of 397,000 pounds of pulverised rock will be handled by the dewatering system. Sedimentation tanks will be used to allow the pumps to handle the separated water. This will minimize the amount of abrasive solids, sedimentation and system cloggings that would lead to a system breakdown. The design of the sedimentation system will be based on calculations of increasing amount of solids. The drill water is collected both from the municipal water line and from a nearby river. Before the water is pumped back to the river, samples are taken on regular basis to ensure that the city regulation of water quality (with regards of chemicals and amount of solids) is not violated.
Lemminkäinen is using between 35 and 45 pumps in each tunnel work, with a total of 160 Grindex pumps being used. With delivery heads of up to 246 feet from the tunnel, it takes both strong and reliable pumps. The high reliability of the Grindex pumps makes them the ideal choice for this pumping project.
This case story can also be downloaded from Grindex Press site together with high resolution images. The address is www.grindex.com/press