Remediation on the former uranium mining and milling site...
Transcript of Remediation on the former uranium mining and milling site...
RemedRemediationiation onon the formerthe formeruranium mininguranium mining andand millingmilling sitesite
(Hungary)(Hungary): Case Study: Case Study
M. CsővariThe presented work is a common
work of the experts fromMECSEK-ÖKO Rt, Pécs, Hungary
andMECSEKÉRC Rt, Pécs, Hungaryand other companies, institutions
„DIFPOLMINE” CONFERENCE Budapest4-8 July 2005
Location of the site
The site has a close connection withdrinking water catchement areas
(T and P).
T P
Water treatment is neccessary for:Mine water
Contaminated groundwater
Geological crossGeological cross--section of thesection of theformer mining siteformer mining site(Western(Western MecsekMecsek))
±0
-700
SandstoneClaystone
P-T Sandstone
Tectonic zoneUranium ore
Legend
Anhydirte Siltstoneaquitard
Limestone M Sand and clay
Pl Loose sand (aquifer)2
Northern shaftsSouthern shaft
Adit
D
D- drinking water aquifer
Anticline
Water treatment processesWater treatment processes
1) Mine water treatmentAnion-exchange process is used for U(TDS~1.6 g/l; U~5 mg/l; As<12 mg/l, Ra~0.3 Bq/l)
2) Groundwater treatmentPump and treat process
(TDS~3-15 g/l; U<0.1 mg/l; Ra~0.08 Bq/l)Heavy metals:As<12 mg/l;
Pilot-scale PRB (ZVI + sand mixture)(in situ groundwater treatment, experiment)
I Mine water treatment stationI Mine water treatment station
Station is situated on the area of former Shaft NI
Mine water
As
Yellow cake productionYellow cake production
B
Packing unit
U-concentrate accretion onthe mixer in dryer causes
some problemsPrecipitation of
uranium peroxide
Mine water treatmentMine water treatmentSorption efficiency for uraniumSorption efficiency for uranium
0
2
4
6
8
10
12
1995 1996 1997 1998 1999 2000 2001 2002 2003 2004Ye ar
U, m
g/l U in mine water.
U effl.
Ueff l.~0.2 mg/l
U~2 t/aExtra water fromremediation activityof HL
U~7 t/a
V~0.44 Mm3/aV~1.2 Mm3/a
The change of uraniumThe change of uraniumconcentration in mine waterconcentration in mine waterover long period (1968over long period (1968--2005)2005)
0
2
4
6
8
10
12
1968
1970
1972
1974
1976
1978
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
2002
2004
Year
U, m
g/l
Volume and concentration were affectedby heap leaching
6-7 mg/l 4.5-5 mg/l35 years
Mill
TP
Pipeline TPI
TPII
II Groundwater treatmentII Groundwater treatmentTailings PondsTailings Ponds
Total volume of the tailings:20.4 kt solid + 32 Mm3 of liquid
Groundwater restorationGroundwater restoration
577000 577500 578000 578500 579000 579500 580000 58050075000
75500
76000
76500
77000
77500
78000
78500
79000
A-01
B-01
C-01
H/1
U-09/1
U-10/1
U-11/1U-13/1
U-14/1
U-16/1
U-17/1
U-18/1
U-19/1
U-20/1
U-21/1
V-01/1
V-02/1
V-03/1
V-05/1
V-07/1
V-08/1
V-10/1
V-11/1
V-13/1
V-14/1
V-15/1
V-16/1
V-17/1
V-18/1
V-19/1
V-20/1
V-21/1
V-22/1V-23/1
V-24/1
V-25/1
V-26/1
V-27/1
V-28/1
V-29/1
V-30/1
V-32/1
V-33/1
V-35/1
V-36/1
V-37/1
V-38/1
V-39/1
V-41/1
VIII/1
X/1
XIII/1
XVIII/1
XXVII/1
Bicsérd-2/F-5
Pellérd-1/F-5
ZA-1
ZB-1
ZC-1
ZE-1
ZG-1 ZH-1
ZI-1
ZB
ZC
ZD
ZF
ZIZJ
R-11
R-12
R-15
R-16
TDS (mg/l) in the shallow groundwateraround the tailing ponds in 2003
1000 4000 8000 12000 16000 20000
0 500 1000 1500 2000
577000 577500 578000 578500 579000 579500 580000 58050075000
75500
76000
76500
77000
77500
78000
78500
79000
A-02
B-02
C-02
G
H
U-09
U-10
U-11 U-12 U-13
U-15
U-16
U-17
U-18
U-21
U-22
U-23
V-01
V-03
V-05
V-07
V-09
V-12
V-13
V-14
V-15
V-17
V-21
V-22V-23
V-24
V-25
V-26
V-27V-29
V-34
V-36
V-37
V-38
V-40
VII
XIIIBicsérd-2/F-3
Pellérd-1/F-3
ZA-2
ZB-2
ZC-2
ZD-2
ZE-2
ZF-2
ZG-2
TDS (mg/l) in the deeper groundwateraround the tailing ponds in 2003
1000 4000 8000 12000 16000 20000
0 500 1000 1500 2000
5-20 m25-40 m
TPI
TPII
18 g/l 4 g/l
S hallow GW5-20 m
Deeper GW25-40 m
TDS
GW contamination
GroundwaterGroundwatercontamination undercontamination under thethe TPTP
25 m10 m
TDS in pore water
-40-35-30-25-20-15-10-50
0 5000 10000 15000 20000 25000 30000TDS, mg/l
Dep
th, m
577000 577500 578000 578500 579000 579500 580000 58050075000
75500
76000
76500
77000
77500
78000
78500
79000
A-01
B-01
C-01
H/1
U-09/1
U-10/1
U-11/1U-13/1
U-14/1
U-16/1
U-17/1
U-18/1
U-19/1
U-20/1
U-21/1
V-01/1
V-02/1
V-03/1
V-05/1
V-07/1
V-08/1
V-10/1
V-11/1
V-13/1
V-14/1
V-15/1
V-16/1
V-17/1
V-18/1
V-19/1
V-20/1
V-21/1
V-22/1V-23/1
V-24/1
V-25/1
V-26/1
V-27/1
V-28/1
V-29/1
V-30/1
V-32/1
V-33/1
V-35/1
V-36/1
V-37/1
V-38/1
V-39/1
V-41/1
VII I/1
X/1
XI II /1
XVI II /1
XXVII /1
Bicsérd-2/F-5
Pellérd-1/F-5
ZA-1
ZB-1
ZC-1
ZE-1
ZG-1 ZH-1
ZI-1
ZB
ZC
ZD
ZF
ZIZJ
R-11
R-12
R-15
R-16
1000 4000 8000 12000 16000 20000
0 500 1000 1500 2000
GroundwaterGroundwatertreatment processtreatment process
Treatment process consist of:• Precipitation of magnesium and
gypsum with calcium hydroxide•Sedimentation and thickening•Filtration
Shallow GW: TDS~10-12 g/lFor treatment
Deeper GW : TDS~3-5 g/lDirect discharge
Groundwater extractionGroundwater extractionsystemsystem
WT
Drainage: 2.8 kmWells: 15+12
Q~0.5 Mm3/a0.3 Mm3/a
Sludge from treatmentSludge from treatment
Mg~17%Ca~17%SO4~26%U~60-70 g/tRa~24 Bq/kg
Sludge7kt/a (with 50% water content)
Treated water:~0.36 Mm3/a
TDS~6-7 g/l (retention time!!)(NaCl~3 g/l)
Gypsum accretion onGypsum accretion onthe surfthe surfaacece of technological equipmentof technological equipment
Critical parts and units must bemonthly cleaned from
gypsum accretion
WaterWater discharge summarydischarge summary
Treated groundwater Treated mine water
Mixing basinTDS:3.2 g/lU:0.2 mg/l
Ra:0.18 Bq/l
Receiver
Data for 2004
Non-treatedwater
(e.g.deeper GW)V:1.27 Mm3
V:0.36 Mm3 V:0.44 Mm3
IIIIII PilotPilot--scale PRBscale PRB(for in situ treatment of GW)(for in situ treatment of GW)
Field test aiming at investigating of long-term performanceof PRB (EU project: EVKI-1999-00035) for removing
of U from GW
Practical solutions are known in first of all inUSA ,but the long-term performance is stillunder investigation
For field test ZVI+sand mixture was selected, thoughdifferent reactive materials were tested in laboratory
and in columns on the field
Permeable reactive barriersPermeable reactive barriers
Permeable reactive barriersPermeable reactive barriers
Funel anf gate systemFunel anf gate system
Uranium contaminated groundwaterUranium contaminated groundwaterIn valleyIn valley ZsidZsid
Valley
Valley Zsid
Monitoring well Hb1/1
Slite contamination of GW was detected in GW on the site
Laboratory experiments in columnsLaboratory experiments in columns
Iron, hydroxiapatite,anion exhange resin,
etc. were tested
Removal of uranium fromRemoval of uranium fromcontaminatedcontaminated GWGW
Uranium can be is removed from GW by steel fibres
0
100
200
300
400
500
600
700
800
900
1000
0 64 74 85 96 106
117
127
137
Sample number
U, µµ µµg
/lFeedHb1/1
Effluent
Changing the general chemistry ofChanging the general chemistry ofwaterwater
Bycarbonate calcium etc. Are dropps during treatment
0
100
200
300
400
500
600
700
54 64 91 100 109 118 127 136
Sample number
kcon
cent
ratio
n, m
g/l
Ca
Mg
HCO3
FeedHb1/1
Colomns inColomns in monitoringmonitoring wellswells
2,3m
6,3m
Plasticpipe Ditch
∆∆∆∆H
Colomn F=8-12cm2 , L=1-1,4 m
drain
Field column experimentsField column experiments
Geochemical processes controllingGeochemical processes controllingGWGW chemistrychemistry
[Fe][CO3] = 2,50E-11 200C
[Fe][OH]2 = 1,64E-14 180C
H2CO3 = HCO3- + H+
K=10-6,3
HCO3-=CO32- + H+ K=10-10,25
[Ca2+] [CO32-]=1.20E-08 200C
Geochemical processes inGeochemical processes inGWGW
Iron concentration vs. pH
0
10
20
30
40
50
7 7.5 8 8.5pH
Fe, m
g/l Fe2+ CO3
2-=FeCO3
Location of the PRBLocation of the PRB
The installation is locatedin a narrow valley atthe foot of WPIII, linkingthe mining area withdrinking water aquifer(Zsid-valley)
WP3
GW flowdirection
PRB
Valley
Principal designPrincipal design of theof theexperimentalexperimental PRBPRB
Soil 50 cmUp stream
Down stream
2.5 m6.8 m
3.8 m
Comp. clay30 cm
HDPE
Bedrock
Bentofix
A
B
Cross-section A-B
Legend: Sand
0.39 t/m3 iron (1-3 mm, 5 t) with sand
1.28 t/m3 iron (0.2-2 mm, 33 t) with sand
Mon. wells
Elemental iron mixed with sand
Spec. Surface:0.7 m2/g
0.2-3 mm
Construction of the PRBConstruction of the PRB
Permian sandstone withsediments
Two layers ofFe+sand mixture
Monitoring wells placed inreactive zones
Construction of the PRB
course ZVI + sandZVI + sandsandclay
HDPE
Bentofix
aquiferspiezometric head
Design of experimental Permeable Reactive Barrier
GW flow
Length:6.8 m;Depth:3.9 mWidth: 1.5m;Two zones;G:39 t ZVI (mixedwith sand)
PRB with monitoring wells
28 monitoringwells
Precipitation of uraniumPrecipitation of uraniumand dissolution of ironand dissolution of iron
Uranium concentratio n pro file in the PRB
1
10
100
1000
-50 0 50 100 150 200width, cm
U, µµ µµ
g/l
Iron concentration profile in the PRB
0
5
10
15
20
25
-50 0 50 100 150 200
Uranium conc. drops inthe first zone
Iron first dissolvesin first zone
than precipitatesin the 2nd zone
Concentration profiles in zones of PRB
Concentration profiles in PRB
0
20
40
60
80
100
120
0 0,5 1 1,5 2width of PRB, m
%fr
om in
flow
Ca
Mg
TDS
SO4
HCO3
Spec. cond.
Fe~20 mg/l
TDS
U
PRB performancePRB performance(August 2002(August 2002--April 2005)April 2005)
Uranium is removed with high efficiency but huge volumeof inert compounds (CaCO3, MgCO3 etc.) is precipitated
EC U(VI) TDS Ca SO4 HCO3 FeµS/cm µg/l mg/l
Inflow 6.9 1400 940 1010 150 320525 0.002ZoneI 7.3 1330 37 937 125 300275 5.5
ZoneII 8.7 865 10 550 10 185299 0.03
pHGW flow direction
Isolines of uranium and calciumIsolines of uranium and calciumconcentrations on the test fieldconcentrations on the test field
U Ca
V.7 Development of uraniumV.7 Development of uraniumconcentration in downstreamconcentration in downstream
monitoring wellmonitoring wellUranium concentration in groundwater after
construction of the PRB
0
200
400
600
800
1000
1200
13.03
.9605
.02.97
06.10
.9714
.05.98
26.03
.9920
.06.00
11.01
.0124
.01.02
15.04
.0228
.11.02
22.01
.0304
.06.03
date
U, µµ µµ
g/l
Const.of PRB
monitoring well:Hb1/1
Performance change
Water passed through the PRB: ~700 m3/aFormed precipitate: ~0.5 kg/m3~ 350 kg/aFree porosity in PRB (original) ~11 m3
Annual losses:~ 0.35x2.7~0.094 m3
in persentage:~1-1.5%
Iron dissolution:~20-30 mg/l Fe(II)G=~700x0.03=21 kg/a
Performance monitoring is continued•by regular water sampling•by planned drillings•by hydrogeological evaluation
Acknoledgement
The research works related to the GWtreatment was
suported by the IAEA (Contract: N0 9114).
The research related to the PRB and dispersionof contaminants under TPs was partially suppotred
by EU(Contract: EVIKI-1999-00186 andEVGI-CT-2002-00035)
Precipitation of gypsum andmagnesium
Kinetic curves o f the prec ipitatio n o fmag nes ium hydro xide and gyps um
0
0.5
1
1.5
2
2.5
0 1 2 3 4
time , hours
conc
entr
atio
n, g
/l
Ca
Mg
I.I.33 ProjectProject cost distributioncost distribution
A Beruházási Program létesítményi sorainak költségeloszlásdiagramja
13%
8%
4%
11%
40%
6%
1%
1%
3%9%
5%
Földalatti létesítmények felhagyása Külszíni létesítmények és területek rek.Meddőhányók és környezetük rek. Perkolációs dombok és környezetük rek.Zagytározók és környezetük rek. Bányavíz kezelésVillamos energia hálózat rekonstrukciója Víz- és csatornahálózat rekonstrukciójaEgyéb infrastrukturális szolgáltatás Egyéb tevékenységTartalék az 1998-2003. éves összegre
TPs
Mines
HLMWT
RoadsRes.fund