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L’UQAT, l’université au cœur des mines
DÉVELOPPEMENT DES CONNAISSANCES
Evaluation of Solutions to Limit Wind Erosion on Tailings Impoundments
Performance of Dust-Control Products Using Index Tests in Laboratory: Dust-Control Product Pre-Selection
By
A Sylvette, PH.D.
I Hane, Msc.
M. Mbonimpa, ing., PH.D.
Juillet 2016
Plan
1. OBJECTIVE
2. TAILINGS AND DUST-CONTROL PRODUCT CHARACTERIZATION
3. DUST-CONTROL PRODUCT PRE-SELECTION TESTS
4. CONCLUSION AND FUTURE WORK
1. Objective
2. Tailings and Dust-Control Product Characterization
Receipt of 5 mine tailings
– 8 dust-control products were received from 4 dust-control product suppliers
– Dust-control products were numbered from 1 to 8
Table. Product (Supplier) | Type
Tailings homogenization
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Physical and chemical properties of tailings
Table. Grain size distribution
Table. Specific Gravity (Gs)
FH and Matagami tailings are denser than other tailings
Table. Specific area
Dumont tailings specific area is higher than those of the other tailings studied
Table. Sulfur/carbon (S/C) content
According to Québec régulation on mine tailings (Directive 019), all tailings except Dumont tailings can be considered as acid generating tailings, since their S/C contents exceed 0.3% and the ratio NP/AP is less than 3.
Mineralogical properties of tailings
Table. Mineralogical properties of tailings
5 types of tailings dominated by:
– Silicates (97% for Éléonore tailings, 85%for Dumont tailings, 82% for Doyon tailings, 56% for Matagami tailings and 53% for FH tailings)
– Oxide (3% for Éléonore tailings, 15% for Dumont tailings, 4% for Doyon tailings, 11%for Matagami tailings and 33% for FH tailings).
– Secondary minerals (gypsum in the tailings of FH (13%), of Doyon (13%) and of Matagami (8%)).
5 types of tailings contain very few sulfide except Matagami tailings that contain 25% of pyrite.
Rheological properties of dust-control product
The dust-control product rheological properties influence the ease of application and penetration of products in the pores of tailings
Table. Dynamic Viscosity (Pa.S)
Tailings preparation
Table. Testing water content:15% ± 2%
3. The protocol used
Tailings without dust-control product
Plate 1
Sun light exposure with UV lamps 1 Cycle (24h UV)
Compressed air jet test
Plate 2
Freeze/Thaw 10 Cycles (2h for freeze and 3-6h for thaw)
Compressed air jet test
Plate 3
Wet/dry under ambient air 5 Cycles (Wet/dry with deionized water)
Compressed air jet test
Tailings with dust-control product
Plate 1
Sun light exposure with UV lamps 1 Cycle (24h UV)
Compressed air jet test
Plate 2
Freeze/Thaw 10 Cycles (2h for freeze and 3-6h for thaw)
Compressed air jet test
Plate 3
Wet/dry under ambient air 5 Cycles (Wet/dry with deionized water)
Compressed air jet test
Tests in triplicate!
(Fan test replaced by compressed air jet test)
Tailings preparation
– Tests were performed in a plate of 19.5 cm diameter
– Fine fraction of tailings (sieving through 200 mesh to remove the aggregates from the tailings) were placed in the plate in a loose state
– Tailings layer with a thickness of 2 cm was placed in the plate at a water content of 15% ± 2%
– The tailings surface was leveled to ensure better application and penetration of the product
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Table. Rate application of dust-control product
Tested samples nomenclature
– Tailings were named A, B, C, D and E
– Plate + tailings without dust-control product were named A0, B0, C0 and E0.
– Plate + tailings with dust-control product were named A6, B6, C6 and E6 etc…
– 405 tests were performed (for all tailings and products)
Table. Product|Tailings
Conditioning: wetting/drying cycles
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Conditioning: freeze/thaw cycles
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Conditioning: Sun light exposure with UV lamp
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Appearance of Eleonore tailings surface untreated (A0) and treated with dust-control products (A6, A7 and A8) after 5 wet/dry cycles
Image. A0
Image. A6
Image. A7
Image. A8
Appearance of Eleonore tailings surface untreated (A0) and treated with dust-control products (A6, A7 and A8) after 10 freeze/thaw cycles
Image. A0
Image. A6
Image. A7
Image. A8
Appearance of Eleonore tailings surface untreated (A0) and treated with dust-control products (A6, A7 and A8) after 1 sun light exposure cycle
Image. A0
Image. A6
Image. A7
Image. A8
Comparison of the appearance of 5 tailings surface untreated after wet/dry cycles
Image. Éléonore (A0)
Image. F.H (B0)
Image. Doyon (C0)
Image. Matagami (D0)
Image. Dumont (E0)
– Presence of cracks on the surface of 4/5 tailings without dust-control product
Comparison of the appearance of the 5 tailings surfaces treated with product #6 (Soiltac) after wet/dry cycles
Image. Éléonore (A6)
Image. F.H (B6)
Image. Doyon (C6)
Image. Matagami (D6)
Image. Dumont (E6)
– Formation of a highly resistant crust on the tailings surface
Comparison of the appearance of the 5 tailings surfaces treated with product #7 (Durasoil) after wet/dry cycles
Image. Éléonore (A7)
Image. F.H (B7)
Image. Doyon (C7)
Image. Matagami (D7)
Image. Dumont (E7)
– Product promote water retention in the tailings
– However, the tailings break up and disperse easily under the air jet test when dry
Comparison of the appearance of the 5 tailings surfaces treated with product #8 (Gorilla-Snot) after wet/dry cycles
Image. Éléonore (A8)
Image. F.H (B8)
Image. Doyon (C8)
Image. Matagami (D8)
Image. Dumont (E8)
– Formation of a highly resistant crust on the tailings surface
Compressed air jet test
– Compressed air jet device was placed at 20 cm from the surface of the plate+ untreated and treated tailings with dust-control product
– Compressed air jet was applied with a pressure of 3 bar for 2 min
– The mass of the plate was determined before and after the test for determining the weight loss
– The surface of the plate+ untreated and treated tailings with dust-control product and its surroundings were observed carefully
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Compressed air jet test results
The following observation were made after the compressed air jet test:
– Detachments of particles;
– Possible detachment of layer when the product formed a thin layer on the tailings surface;
– Mass loss due to evaporation and particle detachment;
– The hardness of the tailings surface untreated and treated with dust-control product was tested by measuring the strength with a hand penetrometer.
The following weightings were used to describe the detachement:
0- Nil
1- Unimportant
2- Important
3- Very important
Table. Compressed air jet test results | Wet/dry cycle
Table. Compressed air jet test results | Freeze/thaw cycle
Table. Compressed air jet test results | UV exposure cycle
Preliminary classification of the 8 dust-control products for the tested conditions
Table. Classification in order of effectiveness|Dust-control product ID
Thanks!
Copyright Soilworks, LLC 2003-. All Rights Reserved. Soilworks®, Soiltac®, Gorilla-Snot®, and Durasoil®are registered trademarks of Soilworks, LCC.
Copyright Soilworks, LLC 2003-. All Rights Reserved. Soilworks®, Soiltac®, Gorilla-Snot®, and Durasoil® are registered trademarks of Soilworks, LCC.