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Uncovering Value in Tailings
Aaron Szumilak
November 2013
Study Overview
FMG Desand process Initial WHIMS tests performed – CYC O/F, UFC O/F, SPT, THK U/F
High level financials and project benefits
Live onsite 2tph pilot program findings
WHIMS vendor comparison
Global Iron grades – Comparison between continents
How Wet High Intensity Magnetic Separation works & Identifying the best value for your investment
Global Iron Grades - Hematite
Brazilian Itabirite
Australian Hematite
Indian Fines Hematite
Head
• 42-46% Fe
• 16-20% SiO2 / 0.2-0.8% Al203
Product
• 62-68% Fe
• 1-5% SiO2 / 0.1-0.2% Al203
Tails
• 8-16% Fe
• 34-42% SiO2 / 0.5-1% Al203
Head
• 55-63% Fe
• 4-9% SiO2 / 1.5-5% Al203
Product
• 57-63% Fe
• 2-5% SiO2 / 1-3.5% Al203
Tails
• 42-55% Fe
• 8-16% SiO2 / 5-10% Al203
Head
• 47-56% Fe
• 4-10% SiO2 / 2-5% Al203
Product
• 56-62% Fe
• 1-5% SiO2 / 0.5-2.0% Al203
Tails
• 26-45% Fe
• 22-36% SiO2 / 4-15% Al203
General FMG Process Flowsheet
Flowsheet by J. Clout, Iron Ore 2013
WHIMS Scoping Study
• Tailings from each unit process
were evaluated
• WHIMS concentrate yields from
6%- 30%
• Increased overall desand
upgrades by treating tails with
WHIMS
• Up to a 9% absolute increase in
Fe
• Up to a 7% absolute decrease in
SiO2
• Up to a 3% absolute decrease in
Al2O3
Flowsheet by J. Clout, Iron Ore 2013
Where’s the best value – Processing Options
1) Thickener U/F
• ~1000 tph, ~50% solids, ~1250 m3/hr
• Contains high amounts of slimes from CYC O/F
• ~16% mass recovery via WHIMS
• Final grades and concentrate quality possibly a concern
1) Upflow Classifier U/F
• ~525 tph, ~9% solids, ~5,000 m3/hr
• Low slime content
• ~30% mass recovery via WHIMS
• Final grades and concentrate quality acceptable
Both options scavenge ~ 160tph of concentrate and contribute an
additional 10% yield to the desand process
How a WHIMS Works
WHIMS Key Operating Parameters
• Gauss = Magnetic Field Intensity • ~900G – Magnetite
• ~6000G – Hematite
• >10,000G – Goethite
• >12,000G – Iron Carbonates
• Rotor RPM = Resonance Time in the Matrix • Increasing RPM = Higher Throughput, lower recovery
• Decreasing RPM = Lower Throughput, higher recovery
• % Solids (w/w) in the feed • > % Solids = greater available mass to recover
• Balance between magnetic yield and entrainment of gangue
• Matrix Gap • Dependant on top size of the feed – typically 3X larger than feed top
size. Will affect field intensity at a given amperage
• Wash Water • Product removal & aids the removal of entrained gangue
2 tph Readings WHIMS Pilot Plant
Only treating UFC O/F
• 10,000G
• 1,200 l/min of non-mag wash water
• 1,800 l/min of mag wash water
• ~40% solids
2 tph Results
Pilot Plant Summary
• Average Yield of 50%
• Average Concentrate Grade
• 59% Fe
• 4.5% SiO2
• 2.2% Al2O3
• Increased overall circuit upgrades by treating
tails via WHIMS
• Up to a 8% absolute increase in Fe
• Up to a 6% absolute decrease in SiO2
• Up to a 3% absolute decrease in Al2O3
Vendor Comparison
20 identical samples in triplicate tested with three vendors Jones – Mbe (ex KHD Humboldt Wedag)
Gaustec – Allmineral
Readings – Mineral Technologies
Vendor Comparison Study Summary
Yield % Fe % SiO2 % Al2O3 %
Gaustec 73.55 58.78 5.12 2.49
Readings 36.59 61.40 3.80 1.90
Jones 62.58 59.10 4.54 2.42
Test Operating Conditions
• 10,000G
• Mids & Mags combined
• ~1200 l/min of wash water
• 40% Feed Solids
• 1.5mm Matrix
Actual Plant – Process Considerations
Key Process Considerations
• % Solids of WHIMS Feed
• % of ferromagnetic material –
LIMS protection
• Oversize in WHIMS Feed – Trash
Screens
• Clean wash water
• Aim to minimize slimes in the
feed
• Area over WHIMS is clear
• Falling Debris
• Maintenance Access
Financial Considerations
• Treating volumes = $$$
• Long equipment lead times
• Brownfields tie in can be costly
• Product recovery & grades are mineralogy dependant
Financials - 50% Engineering Accuracy
Treating 525tph at 9% solids (-150µm)
• CAPEX • ~$30M AUD installed
• OPEX • Plant: ~$8/t
• NPV & IRR • ~$250M & ~170%
• Based on a 10 yr project & $100US/t
• Payback • ~1.5 years based on zero production in the first year
• Margin • ~$70/t
Project Benefits
• Improve upgrades and help lower strip ratios
• Increased revenue
• Improving both production tonnes and final grades
• WHIMS add on improves desand circuit yield from 42% to
56%
• Improves overall desand circuit upgrades producing a higher
quality final product
• Lower C1 cost by ~$0.35/t
• Potential for a new product stream • Potential to produce pellet feed product
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