Some Unique Approaches to Tailings Management and Heap Leaching - - PowerPoint PPT Presentation

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Some Unique Approaches to Tailings Management and Heap Leaching - - PowerPoint PPT Presentation

Oct 11, 2023 130 likes •632 views

Some Unique Approaches to Tailings Management and Heap Leaching Adding Value. Delivering Results . GOLD TAILING STORAGE FACILITY DESIGN AND CONSTRUCTION Project Spotlight: Fort Knox Mine, Alaska GOLD TAILING STORAGE FACILITY DESIGN AND

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Adding Value. Delivering Results.

Some Unique Approaches to Tailings Management and Heap Leaching

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TAILING STORAGE FACILITY DESIGN AND CONSTRUCTION

Project Spotlight: Fort Knox Mine, Alaska GOLD

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TAILING STORAGE FACILITY DESIGN AND CONSTRUCTION

Project Spotlight: Fort Knox Mine, Alaska GOLD

  • Large Embankment Dam converted

to centerline raises

  • Construction of first platform in

deep water

  • Rock fill separator dyke constructed

also in deep water

  • Excavated first into dam to re‐orientate

the “engineered” zones and then re‐ used Seal Zone material

  • High seismic and cold climate area
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TAILING STORAGE FACILITY DESIGN AND CONSTRUCTION

Project Spotlight: Fort Knox Mine, Alaska GOLD Recent second platform and step out on tailings beach

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TAILING STORAGE FACILITY DESIGN AND CONSTRUCTION

Project Spotlight: Fort Knox Mine, Alaska GOLD

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TAILING STORAGE FACILITY DESIGN AND CONSTRUCTION

Project Spotlight: Fort Knox Mine, Alaska GOLD

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TAILING STORAGE FACILITY DESIGN AND CONSTRUCTION

Project Spotlight: Fort Knox Mine, Alaska GOLD

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TAILING STORAGE FACILITY DESIGN AND CONSTRUCTION

Project Spotlight: Fort Knox Mine, Alaska GOLD

1st construction to

  • el. 1488’ over 1st

BWP 2nd construction to

  • el. 1515’ over 1st

BWP Construction of 2nd BWP 1st construction to el. 1515’ over 2nd BWP Spigot discharge Spigot discharge

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Tailings Storage Facility Within a Heap Leach Pad

Project Spotlight: La Quinua Mine, Peru Gold

  • Wrap around leach ore

embankments provide tailings containment

  • Design for high seismic loading
  • Rotational deposition of thickened

tailings to produce drained beaches

  • Separate fluids removal systems
  • 2011/2012 extensive geotechnical

investigation to prove up earlier adopted design parameters

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Tailings Storage Facility Within a Heap Leach Pad

Project Spotlight: La Quinua Mine, Peru Gold

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Tailings Storage Facility Within a Heap Leach Pad

Project Spotlight: La Quinua Mine, Peru Gold Key Issues Leach ore embankments needed to provide the high level of security required of other major tailings dams However, the leach ore is placed in thick 16 m uncompacted lifts to maintain adequate permeability for leaching and is irrigated with a high solution rate (10 L/hr/m2) Loose structure made static and dynamic liquefaction a key issue

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Tailings Storage Facility Within a Heap Leach Pad

Project Spotlight: La Quinua Mine, Peru Gold Design Solution Provide the embankments with wide cross sections to support loading and leaching and thus wide shells Keep side slope leaching rates low (max. 3 L/hr/m2) Thicken the tailings to reduce the amount of water entering the combined facility Use a rotational tailings deposition method from the inside crests of the embankments to build drained and stable beaches against the embankments

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Tailings Storage Facility Within a Heap Leach Pad

Project Spotlight: La Quinua Mine, Peru Gold Design Approach Keep the ore that becomes saturated or near saturated when under leach well‐removed from the outer faces of the embankments and contained behind large unsaturated structural shells

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Tailings Storage Facility Within a Heap Leach Pad

Project Spotlight: La Quinua Mine, Peru Gold

2011/2012 Geotechnical investigation consisted of: Sonic drilling to obtain leach ore samples SCPT testing to evaluate liquefaction potential, residual (post‐liquefaction) undrained shear strengths, and peak undrained shear strengths of the mill sands and leach ore SCPT testing and piezometers installations to fill in gaps from previous installations to evaluate pore pressure profiles within the mill sands and the leach ore embankments Assess potential borrow material for suitability for use in raise berm construction associated with expanding mill sands storage capacity

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Tailings Storage Facility Within a Heap Leach Pad

Project Spotlight: La Quinua Mine, Peru Gold Some dilatant ore Some contractant ore

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Tailings Storage Facility Within a Heap Leach Pad

Project Spotlight: La Quinua Mine, Peru Gold Post Liq Su/p’ = 0.1 Liquefaction of saturated ore is predicted Both findings consistent with previous information Leach Ore

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Tailings Storage Facility Within a Heap Leach Pad

Project Spotlight: La Quinua Mine, Peru Gold

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Tailings Storage Facility Within a Heap Leach Pad

Project Spotlight: La Quinua Mine, Peru Gold Maximum predicted MCE earthquake induced deformation = 0.3 m at toe

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Tailings Storage Facility Within a Heap Leach Pad

Project Spotlight: La Quinua Mine, Peru Gold North Expansion Design Underway Consists of two new storage impoundments:

  • Stage 1 with a capacity of 18 Mt, and
  • Stage 2 with a capacity of 11 Mt.
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Tailings Storage Facility Within a Heap Leach Pad

Project Spotlight: La Quinua Mine, Peru Gold

Leaching

  • perations

will end prior to the construction

  • f the North

Expansion.

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Tailings Storage Facility Within a Heap Leach Pad

Project Spotlight: La Quinua Mine, Peru Gold

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A Possible New Reclaim Water Barge Access

Project Spotlight: Sierrita Mine, Arizona Copper

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A Proposed New Reclaim Water Barge Access

Project Spotlight: Sierrita Mine, Arizona Copper Using Aqua Barriers Filled with Water or Geotubes Filled with Tailings

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A New Reclaim Water Barge Access

Project Spotlight: Sierrita Mine, Arizona Copper

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A New Reclaim Water Barge Access

Project Spotlight: Sierrita Mine, Arizona Copper

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A New Reclaim Water Barge Access

Project Spotlight: Sierrita Mine, Arizona Copper

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Steep and In Places Unstable Slopes to Line

Project Spotlight: La Granja Mine, Peru Copper

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Steep Slopes to Line

Project Spotlight: La Granja Mine, Peru Copper Side Slope Fills

Also serve to provide access and water diversion platforms

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Steep Slopes to Line

Project Spotlight: La Granja Mine, Peru Copper Step 1 Step 2

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Steep Slopes to Line

Project Spotlight: La Granja Mine, Peru Copper Step 3 Step 4

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Steep Slopes to Line

Project Spotlight: La Granja Mine, Peru Copper Step 5

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Steep Slopes to Line

Project Spotlight: La Granja Mine, Peru Copper

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Steep Slopes to Line

Project Spotlight: La Granja Mine, Peru Copper

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Steep Slopes to Line

Project Spotlight: La Granja Mine, Peru Copper

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Steep Slopes to Line

Project Spotlight: La Granja Mine, Peru Copper

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Large Height and Cold Regions Heap Leach Facility

Project Spotlight: Fort Knox, Alaska Gold

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Large Height and Cold Regions Heap Leach Facility

Project Spotlight: Fort Knox, Alaska Gold Largest height heap from toe to crest ‐ current design 800’ but planned to be expanded to 1100’ Maximum of 500’ above liner at any point In‐heap solution collection pond for winter operations Ore is competent granite ‐ free draining and high strength Leaching occurs all year including through very cold winters

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Large Height and Cold Regions Heap Leach Facility

Project Spotlight: Fort Knox, Alaska Gold

Underdrain System and PCMS Plan

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Large Height and Cold Regions Heap Leach Facility

Project Spotlight: Fort Knox, Alaska Gold

In Heap Pond and Solution Collection Pipework

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Large Height and Cold Regions Heap Leach Facility

Project Spotlight: Fort Knox, Alaska Gold

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Large Height and Cold Regions Heap Leach Facility

Project Spotlight: Fort Knox, Alaska Gold

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Large Height and Cold Regions Heap Leach Facility

Project Spotlight: Fort Knox, Alaska Gold

Performance to Date

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Large Height and Cold Regions Heap Leach Facility

Project Spotlight: Fort Knox, Alaska Gold Liner system consistent with industry standard, and using best practice construction QA/QC Double lined area under In Heap Pond – LCRS flows are 0.01 gpm or 2 orders

  • f magnitude less than permit levels

PCMS system for the detection of leaks “located beneath the portions of the liner which have the greater potential for leakage” – nothing reported Groundwater drain system under the HLF that will intercept any seepage from it – any seepage will report to it – no impacts of CN reported Groundwater regime that is contained in the valley and drains to the TSF – seepage cannot exit anywhere else Extensive flow, head pressure and water quality monitoring give results to date that are equal to or better than design

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Large Height and Cold Regions Heap Leach Facility

Project Spotlight: Fort Knox, Alaska Gold Stage 3

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Large Height and Cold Regions Heap Leach Facility

Project Spotlight: Fort Knox, Alaska Gold Stage 5

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Large Height and Cold Regions Heap Leach Facility

Project Spotlight: Fort Knox, Alaska Gold Stage 7

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Large Height and Cold Regions Heap Leach Facility

Project Spotlight: Fort Knox, Alaska Gold

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Large Height and Cold Regions Heap Leach Facility

Project Spotlight: Fort Knox, Alaska Gold

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Large Height and Cold Regions Heap Leach Facility

Project Spotlight: Fort Knox, Alaska Gold

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Adding Value. Delivering Results.

Thank you