Similar to hundreds of mine sites worldwide, Zinkgruvan is being operated on a non-stop, 24/7 basis, with just a few maintenance breaks during the year. Crusher availability is crucial because 100% of the ore has to pass through the jaws before being hoisted up for further processing.
In addition to the zinc-, lead-, copper and silver-containing ore, the C jaws chop all the host rock extracted along the mining process. With a sturdy design, Metso’s proven C jaws can easily reduce even the hardest type of rock. Every year, more than one million tons are crushed with the jaws.
Minimal service needed
Crushing with the first C160B jaw crusher began at Zinkgruvan’s -800 meter level in 2000 with the primary crushing of zinc-lead ore. The second jaw was installed in 2008 for the new copper process.
Blasted ore is taken from the presently operated, -850 meter level, with normal trucks as an outsourced process. One full truckload is fed to the C160s every 10 minutes.
“We are happy with the high reliability of the C jaws. They only require some minor service, therefore providing us with good uptime and steady, continuous feed to our secondary and tertiary crushing and grinding circuits,” says Mine Manager Jan Kläre.
“Basic crusher service and wear part changes are made by our own staff , using Metso’s parts,” he adds.
Service contract with grinding mills and conveyors
Presently, Zinkgruvan is testing Metso’s new PolyMet mill linings in its big grinding mills. With previously used rubber parts, the linings had to be changed in the shell every 9 to 11 months and in the feed head every 6 months.Zinkgruvan and Metso Sweden have more than 11 years’ experience with a service contract that contains grinding mills and conveyors. At the mine site, two Metso service people and one contractor take care of all the related service jobs. Manpower can also be borrowed from Metso’s Grängesberg mine service team of 20 people.
“We expect a better lifetime with Poly-Met linings. Longer change intervals mean a lot to our productivity, because lining changes takes two full working days,” Mine Manager Jan Kläre says.
New mine goes deeper
With an expected mine life of more than 10 years, Zinkgruvan is actively mapping new ore reserves. Experimental holes are being drilled at the new mine section, at the -1110 meter level.