Canadian Experience in Tailings Management

Presented by Leon C. Botham, MSCE, P.Eng.

Golder Associates Ltd. Saskatoon, Outline

¾ History of Development for Uranium Tailings Management in Saskatchewan ¾ Saskatchewan Experience ¾ Beaverlodge, Gunnar, Lorado ¾ Key Lake AGTMF, Rabbit Lake AGTMF, Cluff Lake ¾ Rabbit Lake In-Pit TMF ¾ Key Lake Deilmann TMF ¾ McClean Lake JEB TMF ¾ Ontario Uranium Develoments ¾ Conclusions Introduction

¾ Northern Saskatchewan was primary development area for Uranium mill tailings management technology ¾ No control on mill or mine discharges until 1977 ¾ 4 major phases in development of control of releases from Uranium mines and mills Introduction (cont’d)

¾ Phases of development ¾ Free discharge of tails until 1977: (1st generation) ¾ Engineered surface structures above water table 1979-82: (2nd generation) ¾ Pit disposal with pervious surround, 1982-97: (3rd generation) ¾ Pit disposal with natural surround and engineered tailings: (4th generation) ¾ Progressively higher levels of environmental protection achieved Saskatchewan Sites

110° 60° N.W.T. 105° 60°

Gunnar Lorado Beaverlodge Athabasca a Basin ACTIVE MINE Athabasc ke McClean La Lake INACTIVE TAILINGS AREA Midwest Rabbit Cluff Lake Lake Cigar Lake

McArthur River

Key Lake Precambrian Shield

. hill R Churc LaRonge 55° 55° History

¾ Early focus on radium; ¾ Uranium had no commercial value until after 1940 ¾ Uranium was waste product ¾ 1933 - Radium mine opened at Port Radium, NWT; Refinery opened at Port Hope, Ontario ¾ 1934 - Uranium discovered at Goldfields Mine on , Saskatchewan ¾ 1946 - AECB established to administer Atomic Energy Control Act History (cont’d)

¾ 1949 - Eldorado started mining at Beaverlodge on Lake Athabasca ¾ 1952 - established ¾ 1953 - Beaverlodge Mine commenced production ¾ 1955 - Gunnar Mine commenced production; closed in 1964 ¾ 1957 - Lorado Mine commenced production: closed in 1960 ¾ IAEA established to administer international safeguards History (cont’d)

¾ 1968 - Rabbit Lake deposit discovered ¾ 1969 - Cluff Lake deposit discovered ¾ 1975 - Key Lake deposit discovered ¾ Rabbit Lake began production ¾ First 2nd generation facility History (cont’d)

¾ 1977 - Cluff Lake Board of Inquiry established ¾ 1979 - Mines Pollution Control Branch set up by Saskatchewan Environment ¾ Comprehensive environmental regulations established for uranium mines in Saskatchewan ¾ All mines thereafter subjected to comprehensive joint Federal- Provincial regulation History (cont’d)

¾ 1980 - Cluff Lake begins production ¾ 1982 - Beaverlodge production ceases ¾ Key Lake production begins ¾ Rabbit Lake pit commissioned ¾ First of 3rd generation facilities ¾ 1983 - Cigar Lake deposit discovered ¾ 1985 - Beaverlodge decommissioning completed ¾ Last of 1st generation facilities History (cont’d)

¾ 1987 - McArthur River discovered ¾ 1989 - Joint federal/provincial panel established to review 5 projects ¾ Full review of tailings management practices ¾ 1997 - Deilmann Pit disposal approved at Key Lake ¾ 1999 - McClean Lake production begins ¾ First of 4th generation facilities Uranium City Area Mine Sites

N

URANIUM CITY ELDORADO

E ELDORADO MINE K A AND MILL SITE L E G D O L LORADO R E V A E B

Lake Athabasca

Lake GUNNAR Athabasca Beaverlodge Area

¾ North shore of Lake Athabasca ¾ First production in 1953 ¾ 10 mines in total ¾ Three mills with capacities of, 2000, 2000, 750 tpd ¾ Only Beaverlodge produced after 1964 ¾ Shutdown in 1982 Beaverlodge

¾ Started milling in 1953 ¾ Slurried tailings discharged at 21% solids ¾ Sand fraction removed for backfill ¾ Remainder discharged directly to lake Beaverlodge Tailings System

N ¾ 10.1Mt produced ¾ 4.3Mt used as backfill

¾ No effluent ACE LAKE VERNA LAKE control until TAILINGS VERNA 1977 LINE SHAFT

MILL FAY EEK SHAFT CR ACE

TAILINGS BEAVERLODGE BARIUM LINE LAKE CHLORIDE MINEWATER TREATMENT LAKE MARIE LAKE FOOKES LAKE MEADOW LAKE Gunnar

LEGEND: N ¾ Mine opened TAILINGS in 1955 ROAD ¾ First open pit uranium mine in Sask. ¾ Open pit and LANGLEY underground AIRFIELD mine BAY LAKE ATHABASCA ¾ Milled 5.5 Mt (~4.3ha) of ore (~0.7ha) ¾ Ceased production in 1964 (~16ha)

GUNNAR OPEN PIT ST. MARYS CHANNEL SHAFT

0km 3km Gunnar Site Gunnar Pit & Tailings Area Lorado Tailings Area

N ¾ Mine opened in 1954 ¾ Mill opened in

9 8

0 0 5 1957 5 CRACKINGSTONE 0 8 0 RIVER 9 0 5 80 0 ¾ Custom Mill 0 5 850 7 0 ores from 85 50 0 8 several mines 5 7 ¾ Milled 0.5Mt of 800 ore ¾ Ceased EXPOSED TAILINGS E G operations in ID R NERO LAKE B D 1961 N LA MILL 8 SITE 5 0 0 9 0 0 8 BEAVERLODGE LAKE 9

1 1

5 0

0 0

0

5 0 0 0

850 0 200m 500m Lorado Site Rabbit Lake Site Rabbit Lake Tailings - 1975

¾ Conventional valley dam constructed of cycloned EFFLUENT tailings and STREAM till PRECIPITATION POND WEIR EFFLUENT PIPELINE ¾ First fully BUILDING engineered FILTER TAILINGS PIPELINE tailings BUILDING AND ROAD FLOCCULENT BaCl2 BUILDING containment BUILDING BARGE PUMP structure (2nd generation) TAILINGS AREA ¾ Adequate for APPROXIMATE LIMIT OF Rabbit Lake DEPOSITED TAILINGS ore only Rabbit Lake Pit - 1985

¾ First storage of tailings below water table ¾ First of 3rd generation ¾ Incorporated pervious surround ¾ Segregation and freezing detected in hydraulically placed thickened tailings Rabbit Lake Pit Pervious Surround

MAXIMUM TAILINGS SURFACE BEFORE EARTH COVER & FLOODING

DISCHARGE TAILINGS PLACED IN LAYERS

PERVIOUS BLANKET DEWATERING WELL

DRIFT ROCKFILLED SUMP Rabbit Lake Pit Pervious Surround Cluff Lake Waste Mgmt System - 1982

¾ First jointly regulated tailings facility in PUMPHOUSE SADDLE DAM Saskatchewan BYPASS (2nd generation) LINE

D ¾ Some IV E R S segregation, IO N D FILTRATION PLANT IK controlled by E S Y D BARGE PUMPHOUSE R N A O cross dykes and D P ON T C N E E TAILINGS DISCHARGE LINE S TM discharge A E TAILINGS POND TR BaCL D density A TREATMENT M ¾ No evidence of ice build-up SNAKE LAKE FSL ¾ Site closure in progress

H COMPACTED C IT SOIL/BENTONITE D N IO S R E SNAKE LAKE IV TAILINGS POND D TYPICAL TAILINGS DAM SECTION Cluff Lake Wate Mgmt System - 1999

PRIMARY TREATMENT

LIQUIDS DISCHARGE POND BERM Y R A D N O R C E E S T D E N I LOWER E V K M I SOLIDS T Y A D POND E D TR

M A IN SNAKE LAKE D A M

UPPER SOLIDS POND Key Lake - 1995 Key Lake - 2008 Key Lake Layered Tailings - 1983

¾ Designed on “subaerial” principal (2nd generation) ¾ Segregation and permanent freezing were issues TAILINGS HEADER PIPE ¾ Cross dykes COMPACTED BEACH & SPRAY BAR COMPACTED FILL installed to FILL control SLOPE SUPERNATANT POND COLLECTOR segregation SUMP and reduce freezing ¾ Mechanical UNDERSEAL thawing SAND FILTER BLANKET SEAL PIPE undertaken FREE DRAINING ZONE Key Lake TMF - 1995 Deilmann Pit - 1995

¾ Outwash, till, sandstone, basement ¾ Dynamic groundwater system ¾ Composite design (3rd generation) ¾ Pervious surround on lower level ¾ Hydraulic placement of thickened tailings Key Lake DTMF - 1996

WELLHOUSE DISCHARGE PUMPED TO TREATMENT PLANT

SLURRY PIPE FROM MILL LARGE DIAMETER WELL OR SHAFT

OVERBURDEN

SANDSTONE

UP TO 30m (APPROXIMATE) DISCHARGE

TAILINGS BASEMENT ROCK

WASTE ROCK FILL SIDE-DRAIN OF SELECTED FILTERSAND SUBMERSIBLE HORIZONTAL DRIFT PUMP BACKFILLED WITH BOTTOM DRAIN: PUMPING CHAMBER SELECTED ROCK 3 LAYERS OF SELECTED BACKFILLED WITH SAND, GRAVEL & ROCK SELECTED ROCK McClean Site - 1995 Jeb Pit Natural Surround - 1999

TAILINGS MASS RECLAIM BARGE RAISE WELLS

WATER TABLE

BASE FILTER DEWATERING WELL DEWATERING WELL Jeb Pit

¾ 4th generation ¾ Hydrological and hydro- geological containment ¾ Engineered tailings ¾ Geo-chemical containment ¾ Passive system upon closure Conclusions

¾ 4 distinct stages of tailings development in Saskatchewan uranium mines ¾ Prior to 1977, disposal was in most convenient fashion ¾ First discharged water treatment undertaken in 1977 ¾ Comprehensive regulations instituted in 1979 ¾ Key Lake, Cluff Lake and Rabbit Lake tails 2nd generation facilities ¾ Engineered structures above water table Conclusions (cont’d)

¾ Rabbit Lake pit, Deilmann pit and JEB pit are 3rd generation facilities ¾ Thickened railings below water table: pit disposal schemes ¾ Migration from sub-aerial to sub-aqueous discharge to overcome climatic issues ¾ McClean Lake (JEB pit) is first of 4th generation facilities incorporating “engineered tailings” to address source term concerns Conclusions (cont’d)

¾ Geotechnical engineering has delivered progressively greater degree of environmental protection even though ore grade and complexity has increased dramatically Ontario Uranium Production

¾ Thirteen (13) Uranium mines with nine (9) associated tailings facilities operated in the Elliot Lake area ¾ Over 160 million tonnes of tailings generated during approximately 40 years of operations ¾ Operations at four mines continued into 1990’s ¾ Quirke (1990) ¾ Panel (1990) ¾ Denison (1992) ¾ Stanleigh (1996) Ontario Uranium Production (cont’d)

¾ The tailings facilities for the four mines of interest contain approx. 145 million tonnes of tailings ¾ Tailings have relatively high pyrite content ¾ Acid generation from oxidation of tailings is most serious problem with the tailings ¾ 85 per cent of the radioactivity from the original ore remains in the tailings Elliot Lake Uranium Mines

N Denison Mine TMA-1 Denison Mine TMA-2 Stanrock TMA Quirke TMA Quirke TMA Panel TMA Spanish American TMA Stanleigh TMA Lacnor TMA Nordic TMA Pronto TMA Thank-you! Questions?