Abstract In response to the challenge of recovering particles smaller than -0.45 microns in Mineral Processing, GAUSTEC® has significantly enhanced the Wet High Intensity Magnetic Separation (WHIMS) technology. By Extending the Height of the Magnetic Grooved Plate Matrix, a core component of Jones Magnetic Separator Technology, GAUSTEC® has raised the industry standards. For over fifty years, since the installation of the first Jones separator at VALE Cauê Mine in 1972, the standard matrix height has remained at 220 mm. The worldwide demand to reduce tailings prompted a team of researchers to look for new solutions to improve slimes recovery. After trying traditional methods and process variables it was decided to extend the matrices heights to increase the processing time inside the magnetic field. Evaluating four matrix heights, researchers found that doubling the standard height (2H) provided outstanding results. The 2H matrix recovered 2.5 times more mass from slimes compared to the standard 1H matrix height, in this study. 0.45 045 0 45 -0.4 Processing GAUSTEC WHIMS (WHIMS technology Matrix Technology standards years 1972 22 mm recovery field H (2H results 25 2 5 2. study 0.4 04 4 -0. 197 0. -0 19 - 1

Abstract The Magnetic separation of ultra-fine ore particles has always posed a challenge to the JONES/WHIMS process. Despite many advances in this technology, no effective improvement has been made to its core component: The Magnetic Matrix. The current approach to separate ultra-fine particles teaches that the gap of the matrix and its teeth size must be smaller than usual in order to accommodate the small size of the particles. However, practice proved this approach to be far from ideal. The closing of the gap between grooved plates, whose teeth are smaller, drastically reduces the flow area, reduces the feed capacity, and makes the matrices prone to clogging. In addition, smaller teeth reduce the magnetic field and its gradient, leading to poor results with ultra-fine ore particles. This research proves that bigger teeth are better suited for high intensity magnetic separation of ultra-fines because they avoid matrix clogging thanks to the larger slurry flow area. Additionally, bigger teeth amplify the magnetic field “Bmax” and increases the magnetic gradient “Grad (∆B /∆X)”. The positive results of this new “BigFLUX Matrix” technology, are being displayed in several mining operations worldwide, increasing metallurgical recovery and producing high quality concentrates and low iron content sand from iron ore tailings.

Abstract Tailings recovery has been a constant challenge for most engineers. Along more than five years, GAUSTEC joined major players in the mining Industry to scavenge Iron from tailings produced by flotation making use of WHIMS (Wet High Intensity Magnetic Separation). In the early 1980s, in USA, the US 4,192,738 patent was granted with promising results. Despite this, thirty years have passed with no significant application worldwide. One main reason is reported: the market missed a really high feed capacity WHIMS in order to avoid the huge number of the WHIMS that were available at that time (such projects would typically require more than 20 WHIMS to scavenge iron from tailings produced by flotation plants). Such a huge asset to scavenge low grade iron tailings would not payback. The Mega sized WHIMS launched by GAUSTEC in 2014, the GHX-1400, improved by the Super-WHIMS Technology (18.000 Gauss) and BigFlow Magnetic Matrixes (Gaps smaller than 1.5 mm), faced this challenge. Specially designed ancillary equipment described here also played a decisive role in the scene.

Since its introduction in 1963 by G.H. “Jones”, WHIMS MS has proven to be, worldwide, a major technology for separating several types of ore fines from their contaminants. Unfortunately, despite its superb characteristics, even if the best operational procedures are followed, one main issue lasts. It is the blocking of the matrix gaps by oversized particles. Protection screens have been employed to wipe out this blockage, though only partially effective. Creative methods and tools have been developed to facilitate and speed up the cleaning process. But, in fact, along 50 years, the matrix blockage nightmare lingered defying the minds involved with Whims operation. The recent environment demands and the need to reduce costs by recovering ore ultra-fines currently being disposed in tailing ponds, further posed a new challenge. Reportedly these ore ultra-fines, typically below 75 microns, demand smaller gaps for its recovery than today’s bottom limit 1.5 mm. The blockage issue worsens even more and to solve it, Gaustec Magnetism, after two years of research and test work, finally succeeded in developing The Brand New NoBLOCK® Technology presented here.

Dez anos de pesquisa e estudos levaram a um importante desenvolvimento no campo da separação magnética de alta intensidade - WHIMS. Com essa tecnologia de ponta, a Gaustec estabeleceu um novo recorde mundial nessa classe de separadores magnéticos, alcançando a capacidade de até 1400 tph de alimentaçao de finos de minério de ferro com o novo GHX-1400. Embora minas com baixo teor de ferro sejam beneficiadas com essa tecnologia, o foco aqui é centrado na recuperação de barragens de rejeitos de minério de ferro de baixo teor, considerando o seu impacto positivo no meio ambiente e em função de tal tecnologia permitir a sua viabilização comercial. Com base na nova tecnologia desenvolvida, a construção, na Itaminas Mineração/Brazil, de uma planta de concentração foi iniciada em 2012 para tratar rejeitos com 45% de ferro. Essa planta entrou em operação no corrente ano. Em função dos bons resultados obtidos com essa primeira unidade, foi iniciado o projeto de construção de uma segunda planta do mesmo tipo, com o objetivo de reduzir o rejeito para 18% de ferro, com operação prevista para 2014.

Ten years of continuous research and development have led to a major improvement in the field of iron ore Wet High Intensity Magnetic Separation - WHIMS. With this cutting-edge technology, Gaustec has established a new world record in this class of Magnetic Separators, by providing a sheer feed rate of up to 1400 tph for iron ore fines. Although low-grade iron ore mines will benefit from this new technology, focused on herein is the reclaiming of low-grade iron ore tailing from ponds, having in mind its huge positive environment impact and business opportunity. Based on this newly developed technology, the construction in Brazil of a Concentration Plant started in 2012 for dressing iron ore tailings at 45% Fe grade, at Itaminas Mine. This plant went into operation this year. Based on the good performance of this first unit, the construction of a second Concentration Plant of the same type, to further reduce to 18% Fe in the tailings, is under way, scheduled to be started-up in 2014.