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 Hazardous Materials Highlights

Mine Waste Materials Overburden Soils 1.6 million Waste Rock Life of Mine Tonnage Overburden Soils 1.6 million Waste Rock 12.8 million Low Grade Ore Recovery Rejects 0.1 million Processed Coarse Kimberlite (Coarse PK) 2.1 million Processed Fine Kimberlite (Fine PK) 0.4 million

Mine Waste Materials JERICHO EKATI Overburden Soils 1.6 million 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 - Recovery Rejects 0.1 million Coarse PK 2.1 million 1.3 million Fine PK 0.4 million 2.6 million

Production Rates for Waste Materials 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 No Ice Entrainment El. 527: Top of Dams Freeboard El. 525: Top of Core El. 523: Spillway Water 1,410,000 m3 El. 517 Fine PK ≈ 380,000 m3

PKCA Storage Capacity No Ice Entrainment Extensive Ice Entrainment 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 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

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