The Suurikuusiko gold deposit in Finland was discovered in 1986 when workers blasting rock for a road cutting noticed specks of gold. The deposit is located in Kittila, a popular holiday region located north of the Arctic Circle in Lapland.
In 2008 Agnico-Eagle, a Canadian company, started to mine the deposit. The Kittila mine is now the largest gold mine in Europe, processing around 5,000 tons of ore per day. It is estimated there are about 4.4m ounces of gold to be mined, of which almost a third has now been recovered.
The mine has over 60km of tunnels. As with any mining operation, it is vitally important to dewater the mine for both safety and operational reasons. Fusion’s distributor in Finland, Pipelife Finland Oy, won the contract to supply the discharge pipe for the Kittila mine: over 23km of 710mm and 630mm SDR 17 PE100 pipe! The project also included chambers, hydrants, remote monitoring systems and custom fabrications. The final destination for the discharge water is a nearby river.
The most critical element of the discharge system is the diffusor (see image above and to the left). The diffusor sits at the end of the pipeline, buried beneath the river bed with only the ends of the outlet ‘arms’ showing. The role of the diffusor is to release discharge water into the river in a controlled manner, thereby avoiding vortices, scouring of the river bed sedimentation and other potential disturbances to the normal river flow.
The initial design of the diffusor was created by a design engineering consultancy. Pipelife’s engineers, in conversation with Fusion Group’s specialists, proposed some modifications to the design to improve its performance. The diffusor has nine outlet arms, eight of which are attached to the pipe using Fusion’s new 630 x160mm branch saddles with understrap.
Stephen Tann is Fusion Group’s Technical Manager:
‘The Fusion branch saddle design used in this project consists of a single lightweight moulding less than 6kg, held in place during the electrofusion welding process by three understraps. The body of the fitting incorporates guidelines as to the optimal torque settings for the straps.
There has been an enormous amount of testing behind the scenes to perfect the branch saddle’s design to enable it to be welded in temperatures ranging from -10˚ to + 40˚c without the need for any temperature compensation during the welding cycle, but at the same time maintain an efficient heating cycle (460 seconds on our 630 x 160mm saddle).
Fusion’s understrap and underpart family of 90-180mm full bore outlet saddles can be used on pipe mains from 90mm to 630mm, including solutions for pressurised and non-pressurised installations.
Full technical details and dimensions are provided in the Fusion Group Global Offer brochure which can be downloaded from our website.’
Mika Ervasti, Product Manager for Pipelife Finland, was part of the Pipelife team working on Kittila project. Mika, impressed by the design and quality of the new branch saddles, provided a direct quotation:
‘Just wanted let you know that the new big branch saddles surprised us very positively! Great JOB! That those had integrated strips with mention of required torque force is supreme! Very good design = best in market that I’ve seen!’
The final outlet arm is located at the end of the diffusor and is attached to a moulded end cap secured by a Fusion 630mm electrofusion coupler.
The diffusor was due to be installed by the end of August 2020.
Fusion Group and Pipelife International have worked together since 2013. Fusion supplies the electrofusion fittings that complement Pipelife’s extensive polyethylene pipe systems and fabrication offer. Together we are active in markets that stretch from The Netherlands to Croatia, Greece to Sweden, and Estonia to France.
