Mine Waste Management

Presented by Cam Scott, SRK Consulting

Content of Mine Waste Management Presentation

• Overview of mine waste materials

• Waste dumps and stockpiles Layout adjustments Foundation conditions Design section Construction methodology

• PKCA Layout & storage capacity Foundation conditions Design section Construction methodology

• Hazardous Materials

• Highlights

Material Life of Mine Tonnage

Overburden Soils 1.6 million

Waste Rock 12.8 million

Low Grade Ore 1.6 million

Recovery Rejects 0.1 million

Processed Coarse Kimberlite (Coarse PK)

2.1 million

Processed Fine Kimberlite

(Fine PK)0.4 million

Mine Waste Materials

Material Life of Mine Tonnage Tonnage in 1 Year (2002)

Overburden Soils 1.6 million 5.5 million

Waste Rock 12.8 million 41.2 million

Low Grade Ore 1.6 million -

Recovery Rejects 0.1 million -

Coarse PK 2.1 million 1.3 million

Fine PK 0.4 million 2.6 million

Mine Waste Materials

JERICHO EKATI

Production Rates for Waste Materials

Fine PK

Coarse PK

Recovery Rejects

Low Grade Ore

Waste Rock

Overburden Soils

1 2 3 4 5 6 7 8 9 10

Years

Layout of Waste Dumps and Stockpiles

Foundation Conditions at Waste Dump/ Stockpile Sites

• Consist of either: Bedrock, or Bedrock with isolated soil deposits

• All sites underlain by permafrost

Typical Section through Waste Dumps and Stockpiles

Dump/Stockpile Construction(except Recovery Rejects Dump)

• To enhance physical stability: Organic soils in toe area to be stripped Material to be end-dumped in layers Overall slopes to be about 21 degrees

• To enhance geochemical stability A frozen layer to be maintained in the base of the

dumps/stockpiles For the low grade and coarse tailings stockpiles, a

layer of coarse, granitic waste rock will provide separation with any organic soils

Recovery Rejects Dump Design and Construction

• Organic soils to be stripped

• Compacted granitic waste rock to be used to develop a uniform base

• Stockpile to overlie an HDPE (plastic) liner bedded on either side with esker sand

• Overall slopes of about 21 degrees

Layout of PKCA

PKCA Storage Capacity

El. 527: Top of Dams

El. 525: Top of Core

El. 523: Spillway

El. 517

Freeboard

Water

1,410,000 m3

Fine PK

≈ 380,000 m3

No Ice Entrainment

PKCA Storage Capacity

El. 527: Top of Dams

El. 525: Top of Core

El. 523: Spillway

El. 517

Freeboard

Water

1,410,000 m3

Fine PK

≈ 380,000 m3

Extensive Ice Entrainment

El. 527: Top of Dams

El. 525: Top of Core

El. 523: Spillway

El. 519

Freeboard

Water

1,013,000 m3

Fine PK

≈ 760,000 m3

No Ice Entrainment

Foundation Conditions at PKCA

Consist of:

• Bedrock, or soil overlying bedrock, on the abutments

• Glacially deposited boulders/cobbles in a till matrix of silt, sand and gravel in the valley floor

• Underlain by a fault

• All dam sites are underlain by permafrost that extends well into bedrock

PK Containment (Dam Design)

• Facility classification: low consequence category

• Containment provided by ice core dams

• Dams at PKCA are 9 to 12 m high and the settling pond dam is 6 m high

• Allows for significant ice entrainment

• Allows for water management and flood storage

• Design based on 2,475-year earthquake

Dam Design – Typical Section

Frozen core

PKCA Construction

• Conventional ice core dam construction procedures using an experienced contractor

• Mainly waste rock and esker sand

• Winter construction

Hazardous Materials

• Petroleum• Hazardous Materials• Hazardous Wastes• Ammonium Nitrate Storage

Mine Waste Management Highlights

• Waste dumps and stockpiles Location of 3 dumps/stockpiles adjusted to

stay in one catchment Dump/stockpiles designed and constructed

to enhance physical and geochemical stability

• PKCA

Low consequence classification Adequate storage capacity Containment provided by the integration of

ice core dams with permafrost foundation Conventional construction methodology

• Hazardous Materials Handled using appropriate methods