Boliden Odda AS was established in 1924 and quickly became one of the world’s leading producers of zinc. Prior to

Peter Richardson, Plant Metallurgist at Renstrцm Mill and Doug Corsan, VP Sales at Knelson stand beside KC-XD30 Concentrator which has contributed to 4% increase in plant recovery

the start of World War II, Boliden was producing 46,000 tonnes of zinc annually. The disruption caused by the war  dropped production dramatically, however, over the decades following the war the company experienced dramatic growth and by the mid-1980’s annual zinc production hit 140,000 tonnes.  

In January 2004, the “New” Boliden AB of Sweden was formed through an asset swap with Outokumpu of Finland. The deal left New Boliden with three core operating divisions – mining, zinc smelting and copper smelting.

Shortly after this reorganization, the mining division undertook an initiative to evaluate opportunities for process improvements including the evaluation of modern gravity concentration technology at several of their plants.

Gravity recoverable gold (GRG) tests were conducted at the Knel son Research and Technology Centre on the various ores treated at the Renstrцm mill. The tests yielded positive results, which gave New Boliden the confidence to pilot test a production-scale fully automated KC-XD30. New Boliden acquired the pilot unit on a rental with option to purchase basis and within 3 months a purchase decision was made.

This technical paper discusses the specifics of the GRG tests and the subsequent verification of scale-up predictions made by KRTC through circuit modelling with KC*MODPro. The successful implementation of the Knelson Concentrator at Renstrцm has lead to the purchase of a second unit to complete the gravity circuit upgrade.

An excerpt from the paper:

“After installation of the Knelson Concentrator, the gold grade in the tailings have decreased at the same time as the calculated head grades have increased. The Au grade in the concentrate has increased more than 2.5 times, and the total Au-recovery to gravity and flotation has increased by more than 4%-units.” Read complete paper…

 Knelson Concentrator – New Gravity Equipment at the Boliden Concentrator
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