Tailings Characterization

Jerónimo CovacevichPractice Lead Tailings

Tailings Characteristics

• Production parameters:• Average production: 50 Mton/year

• Solids content: 40% w/w

• Approximate Particle size distribution (PSD):– D90 à 160 µm– D80 à 110 µm– D60 à 75 µm– D50 à 40 µm– D20 à 10 µm

• Clay content:– 0-25% (Kaolinite and montmorillonite)

• Geochemical parameters:• pH: 7 (neutral)

• Potential acid generator

• Tailings Mineralogy:– Silicate à 29-92%– Carbonate à 2-83%– Sulphide à <1-40%– Sulfate à <1-10%– FeOxide à 0-8%– Others à ~2%

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• The concentrator processes different Ore types and produces different products out of them.

• The process runs in batches of one Ore type ranging from 3 to 20 days. Only permitted reagents are used.

• Tailings characteristics differ from one Ore type to the other.

• Tailings are taken from rougher flotation and then flow by gravity to the Tailings Dam at an average of 45% solids w/w. No dewatering process is applied.

• The Concentrator processes 140.000 tpd of ore in average producing equivalent amount of solid tailings in the form of slurry mixed with around 170.000 m3 of water every day.

Characteristics of the process

4th August 2020Tailings Characterization

• Solids SG is in average 3.2, although depends on the Ore type.

• Slurry density is in average 1.44 tons/m3.In situ tailings is in average 1.76 tons/m3

• Typical tailings discharge to Tailing Dam is around 9,000 m3/h

1 2 3 4 5 dimensions

SG 3,17 3,1 3,25 3,29 3,21

<74 um 44,4 - 46 52,7 - 53,1 51 - 52 51 48,1 - 49,3 %

<20 um 16,7 - 18,3 20,5 - 21,7 21,5 - 22,3 19,4 - 20,4 18,7 - 18,9 %

D50 89 - 93 68 - 69 70 72 76 - 79 um

D80 276 - 288 192 - 195 210 - 213 188 - 190 199 um

D85 349 - 363 228 - 230 248 223 232 um

Residual metals by Ore Type (year 2019)

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Chemical composition

4th August 2020Tailings Characterization

%Cu %Zn ppm Ag ppm Bi %Mo %Fe %Pb ppm As

Average(2001 - 2020) 0,113 0,172 3,1 17,7 0,010 9,626 0,009 36,0

Range(Last 5Y) 0,071 - 0,1 0,08 - 0,162 1,7 - 2,7 4,7 - 26,6 0,006 - 0,01 3,621 - 12,162 0,003 - 0,01 9,7 - 38,4

Range(Historical) 0,071 - 0,231 0,08 - 0,313 1,7 - 5,6 4,7 - 39 0,006 - 0,016 3,621 - 13,513 0,003 - 0,023 9,7 - 48,9

Ore type %Cu %Zn ppm Ag ppm Bi %Mo %Fe %Pb ppm As

1 0,104 0,082 1,3 2,4 0,005 4,378 0,002 6,8

2 0,092 0,265 2,3 40,3 0,007 8,371 0,010 36,2

3 0,095 0,152 2,9 29,7 0,003 4,354 0,004 13,6

4 0,212 0,363 7,0 28,2 0,014 5,971 0,010 75,8

Residual metals (2001 - 2020)

Tailings Mineralogy

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Tailings Rheology

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Weight of the Ore type in tailings stream

28%

36%

30%

2% 4%

Ore Type

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Ore type• Average next 17 years

• 1 247 [Mton] 28,3%

• 2 312 [Mton] 35,6%

• 3 266 [Mton] 30,4%

• 4 17 [Mton] 1,9%

• 5 33 [Mton] 3,8%

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0,0%

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100,0%

2.021 2.022 2.023 2.024 2.025 2.026 2.027 2.028 2.029 2.030 2.031 2.032 2.033 2.034 2.035 2.036 2.037

Ore Type

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