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Zs. Berta-M. Csıvári
Technical Meeting on Uranium Exploration and Mining Methods
MECSEK-ÖKO Zrt., Pécs, Hungary
Amman, 17-20 November 2008
HISTORY OF THE URANIUM PRODUCTION IN MECSEK
Mecsek Mountain, Village:Kıvágószılıs
LOCATION OF THE SITELOCATION OF THE SITE
One district inshouthern
part of Hungary
Site is situated next tothe drinking waterchatchment area
Pécs
Tailing Pond
#1. Shaft
#2. Shaft
#3. Shaft
#4. Shaft#5. Shaft
0 1000 2000 3000 4000 5000( m )
TPP
T
Miningarea
Main task is: protectionof the drinking water basin
PRODUCTION SUMMARY (1958PRODUCTION SUMMARY (1958--97)97)
Type of ore Mass of ore Grade U Quantity of U Recovered and sold U
U in tailings (wastes)
million t g/t tonne tonne tonneOre exported 1.4 1 524 2 195
Waste rock* 19.3 53 1 029 1 029 Ore processed inthe mill 18.8 1 002 18 916 17 534 1 382
Heap leached ore 7.2 130 942 545 397
Total 46.8 23 082 18 103** 2 808
* including rejects from radiometric sorting** including 22 tonne uranium from water treatment Exploration1953-56
Opening of the mines1955-58
Mining 1958-97 Remedi1997-0883 M EUR
Processing, 1962-97Long-term mon. ~2.5 M EUR
EXPLORATION WORKEXPLORATION WORK
1952. Agreement was signed between the Hungarian and Soviet Governments on starting the geological survey on uranium deposits
1953. Soviet geologist equipped with appropriate instruments arrived in Hungary one of that teams (geophysics T. Csuprova and L. Puharszkij) detected unusual high anomaly at MECSEK (Kövágoszılıs). This event is considered as the discovery the uranium deposit in Hungary
Geiger-Müller counterMeasuring the emanation activityDetermination of U.
Geiger-Müller counter
Foot-gamma and car-borne prospecting,
Digging trenches, shallow exploration shafts, hand-drillingAirborne gamma- prospecting
Emanation measurements on the sitesWater analysis for UComplex geological mineralogical and geochemical evaluation of the data
Deep drillingsGeophysical measurements using (electrical conductivity survey) for detecting e.g. the foults
METHODS OF PROSPECTINGMETHODS OF PROSPECTING
Lenght of the drillings
Quantity of the drillings
LENGHT AND NUMBER OF THE DRILLINGSLENGHT AND NUMBER OF THE DRILLINGS
m N
GEOLOGICAL GEOLOGICAL MAP and MAP and CROSSCROSS--SECTION SECTION OF THE OF THE
WW--MECSEKMECSEK
S
N
S N
Uranium was found in the upperPermian geological set in grayish/greensandstone
The ore is situated in the upper Permian sandstonein greyish-green layers (productive zone)Total estimated solid ore reserves (U~0.12%):
39 Mt (up to –1300 m depth)Mined out solid ore :
20 Mt (28 Mt in form of run-off-mine ore )Reserves left behind: 19Mt
12 Mt (1200-1300 m) 7 Mt (1000-1200 m)
GEOLOGICAL RESERVESGEOLOGICAL RESERVES
URANIUM MINERALISATION IN THE OREURANIUM MINERALISATION IN THE ORE
Uranium oxides in clayey-kvarc
cementing phase BranneriteSecondary minerals (in
ultraviolet light)Main uranium minerals:•Uranium oxides•Coffinite•Brannerite•Secondary minerals
Uranium oxide (1) and coffinite (2) in
carbonateous cementing phase
572000 573000 574000 575000 576000 577000 578000 579000 580000 581000 582000 58300079000
80000
81000
82000
83000
84000
85000
86000
87000
88000
89000
90000
II.
V.
I.
III.
IV.
KÕVÁGÓSZÕLÕS
CSERKÚT
KÕVÁGÓTÖTTÖS
BAKONYA
PÉCSRoad #6
0m 2000m 4000m 6000m 8000m 10000m
MINING PLOT AREAMINING PLOT AREA
UNDERGROUND MINES UNDERGROUND MINES MINE HEADFRAMESMINE HEADFRAMES
7.3 Mt
Only underground mining ( 5 mines, 119-1118 m); Two shallow (119-149m) and two deep shafts(700-1118 m), one with adits;
46.4 m gallery /1000t ore; The ore was found in form of lenses, therefore the run-off-mine ore was diluted with waste rocks; There was no backfilling of workings.
Shaft N4 1971 (-700 m) Shaft N5 1978 (-1118 m)
1.35Mt3.1 Mt
Shaft N1 1957 (-119 m)
SOME PHOTOS ON THE UNEDERGROUND MINING WORKSSOME PHOTOS ON THE UNEDERGROUND MINING WORKS
EXPLORATIOM IN MINE EXPLORATIOM IN MINE (DRILLINGS FROM GELLERIES)(DRILLINGS FROM GELLERIES)
242 m mine exploration drilling /1000t ore;
GEOPHYSICAL EXPLORATIONS GEOPHYSICAL EXPLORATIONS IN THE MINEIN THE MINE
Logging
Documentatioon of the gallery walls
IMPROVEMENT OF THE WORK CONDITIONS IMPROVEMENT OF THE WORK CONDITIONS FOR MINERS OVER 1956FOR MINERS OVER 1956--97 PERIOD97 PERIOD
1 WLM=5 mSv
WLM/a
Radiometric sorting station (with crushing
and sizing)Capacity: ~1.2 Mt/a
Capacity of the mill(for ore): 600 kt/a
35 ha
PROCESSING PLANTPROCESSING PLANT
Run-off-mine ore
Waste rockU<100 g/t
Low-grade ore U=100-230 g/t
Industrial-grade oreU>230 g/t
Radiometric up-grading
Mill-grade oreU~1000g/tγ=67%
RejectU<170 g/tγ=33%
Heap LeachingU~140 g/t (CO2~3% S~0.1%)
U=100-170g/tU<100 g/t
For HL alkaline leaching was selected because of high CO2 and low S content
RCS
To the mill
GGENERALENERAL FLOWFLOW SHEETSHEET OF THEOF THEOREORE PROCESSINGPROCESSING. R. RADIOMETRICADIOMETRIC SORTINGSORTING
OPERATION OF THE RADIOMETRIC SORTING STATION OPERATION OF THE RADIOMETRIC SORTING STATION AND THE EFFICIENCY OF THE R&D WORKSAND THE EFFICIENCY OF THE R&D WORKS
ND 424L 76X50
Detectionefficiency: 5600 cps/gU
Decreasing thebackground and installation more sensitivedetectors
The U in rejectsdecreased, the% of itsincreased
Closingperiod
1958
Performance of the sorting
Leaching (in four stages)
U rec.~95%200 g/l 15 g/l
Recovery of U from pulp
Product:Ca-diuranate
Neutralization of the barren pulp
(pH~7-7.5)
Disposal in tailings ponds(TDS~22 g/l, MgSO4 + NaCl)
CaO~25 kg/t; CaCO3~11.6 kg/t
Mineralization: brannerite;
H2SO4~100 kg/t
Ion exch.: 0.1 l/tHCl~5.3 kg/tNaCl~4.4 kg/t
Mill-grade ore (18.9Mt)(U~0.1%) CO2~ 4-2.6%
Crushing and Milling
CaO
Pyrolusite
Refractory oreCo-current syst.
GGENERALENERAL FLOW SHEETFLOW SHEET OF THE MILLOF THE MILL PROCESSPROCESSAcid leaching
QUANTITY AND THE GRADE QUANTITY AND THE GRADE OF THE ORE PROCESSED (1962OF THE ORE PROCESSED (1962--97)97)
DIRECT COST DISTRIBUTION DIRECT COST DISTRIBUTION BETWEEN THE MAIN MATERIALSBETWEEN THE MAIN MATERIALS
Material Spec. cons.kg/tSulphuric acid 102.5Lime 21.6Hydrochloric acid 1.8Pyroluzite 22Salt (NaCl) 4.2Anion exchanger 0.04Ball 0.99Limestone 18.6Electric energy 31.75 kWh/t
Cost distribution. %
Pad construction for heaps
The pad was sealed with plasticfoil strips(and sticked with bitumen)
At the very beginning 1.2 m wide foil strips later on wider ones were used
Drain from WRWood chips
PAD PREPARATION FOR HEAPS PAD PREPARATION FOR HEAPS (1965)(1965)
View on the heaps
33 ha
~5 Mt
Site N2
ColumnsPad readyfor lining
HEAP HEAP LLECHING SITEECHING SITESS
Recovery :55-70%5 kgNa2CO3/t
Employees And Uranium Output Between 1956-1997.
010002000300040005000600070008000900019
56.
1958
.19
60.
1962
.19
64.
1966
.19
68.
1970
.19
72.
1974
.19
76.
1978
.19
80.
1982
.19
84.
1986
.19
88.
1990
.19
92.
1994
.19
97.
Year
Emplo
yees
0
100
200
300
400
500
600
700
800
Metal
l in To
nne
EmployeesUranium in tons
130 Employees
Employees of the companyCHANGE THE NUMBER OF EMPLOYEESCHANGE THE NUMBER OF EMPLOYEESAND THE U PRODUCTION BY YEARSAND THE U PRODUCTION BY YEARS
2008
Prod. cost >60 $/kg
REMEDIATION OF THE SITE REMEDIATION OF THE SITE (1998(1998--2008) 2008)
Government Decree 2161/1994. (30. XII.) on the future of the uranium mining, decision on shut down the uraniummining Elaboration of the remediation concept for the site (1996)Environmental Impact Study Report and issuing the Environmental Licence by the authorities the MPL for the critical components (1997)Submission to the Government the Investment Plan which was divided into 10 sub-remediation project (1997)
A Beruházási Program létesítményi sorainak költségeloszlás diagramja 13%
8%
4%
11%
40%
6%
1%
1%
3%9%
5%
Földalatti létesítmények felhagyása Külszíni létesítmények és területek rek.Meddıhányók és környezetük rek. Perkolációs dombok és környezetük rek.Zagytározók és környezetük rek. Bányavíz kezelésVillamos energia hálózat rekonstrukciója Víz- és csatornahálózat rekonstrukciójaEgyéb infrastrukturális szolgáltatás Egyéb tevékenységTartalék az 1998-2003. éves összegre
Planned cost of remediation (1997): 18.5 Billion HUF (~80 million US$)~ 4 US$/kgU; Actual cost (2008)~100 US$/kgU
Closing of underground minesReclamation of waste rock pilesReclamation of tailings pondsReconstruction of the electricnetworkOther infrastructural serviceReserve
Reclam. of surficial facilities and areasReclamation of heap leaching sitesWater treatmentReconstr. of water and sewage systemOther activities (staff etc.)
DIRECT COST DISTRIBUTION DIRECT COST DISTRIBUTION BETWEEN THE MAIN MATERIALSBETWEEN THE MAIN MATERIALS
Requirements Requirements establishedestablished byby thethe authoritiesauthorities. . MPL of MPL of thethe radiologicalradiological contaminantscontaminants
Restoration of waste rock piles and tailings ponds
• 222Rn exhalation rate: 0.74 Bq/(m2s)• 222Rn concentration outdoors: background + 20 Bq/m3• Ambient gamma dose rate: background + 200 nGy/h• 226Ra activity concentration of soil
- in the uppermost 15 cm layer: background + 180 Bq/kg- in the following 15 cm layers: background + 550 Bq/kg
MPL- Maximum permitted level
All fuel-contaminated soil was removed (4347 m3) (3255 m3 rocks, treated microbiologically on surface);
Backfilling of shafts mainly with waste rocks found on the site;Shaft towers have been blasted, together with most facility buildings;
All sites are remediated (most part of the waste rocks was hauled to WPN3);
Total cost of remediation: ~11. 7 million:US $~0.25 US $/t of mined out rocks (46.8 Mt)
RREMEDIATIONEMEDIATION OF THE SHAFTS OF THE SHAFTS AND AND
THEIRTHEIR SURROUNDINGSSURROUNDINGS
Schaft No. IV. and ventillation shaft No. IV. before and after the remediation
→
→
Remediation of the ventilation shaft N4 Remediation of the ventilation shaft N4 and transporting shaft N4and transporting shaft N4
0 4,000,000 8,000,000 12,000,000
1999-08-28
2003-08-27
2007-08-26
2011-08-25
2015-08-24
2019-08-23
2023-08-22
0 200,000 400,000 600,000 800,000 1,000,000 1,200,000volume of cavities [m3]
-800
-600
-400
-200
0
200
400
water
leve
l [mAs
l]
Adit level
Legendwater level (mAsl)volume of cavities (m3)
2016-2018
±0
-700
Sandstone/ClaystoneP-T SandstoneSandstone
Tectonic zoneUranium ore
Legend
Anhydirtemarl/
Siltstoneaquitard
Limestone M Sand and clay
Pl Loose sand (aquifer)2
Northern shaftsSouthern shaftAdit
D
D- drinking water aquifer
ChallangeChallange: : weatherweather mineminewaterwater fromfrom deepdeep minesmineshas has toto be be treatedtreated??
FLOODING OF THE MINESFLOODING OF THE MINES
I II IV VMine water treatment
IIIWaste rockpiles
IIII II
Mines
To dischargebasin
U~0.4 mg/l
U<1 mg/lU~4 mg/l
FA
On sitetreat.
UO4x2H2O
Under flooding
MINE WATER TREATMENTMINE WATER TREATMENT
Total mass of waste rocks (on 10 piles): 19.2 MtU~1055 t
WP N3: 12.2 Mt
For backfilling only 0.1 Mtof waste rocks were used
Measures:Relocation, hauling, reconturingCovering with ~1 m thick soil layer
RevegetationSeepage treatment (U removing)
Total cost of remediation: ~2.39 million US $ (incl. 2 million US $ for HL wastes);
~0.09 US $/t ( waste rocks + HL residues)
RREMEDIATIONEMEDIATION OF THE WASTE ROCK PILESOF THE WASTE ROCK PILES
The most contaminatedsoil was found on the ore and acidstorage areas, as well asunder the yellow cake production facilities.
Scraps of mill balls
Total cost of remediation of the mill site:~ 5 million US $
Demolition
Clean-up with replacingof the contaminated soil(0.35 Million m3)
RREMEDIATIONEMEDIATION OF THE MILL SITEOF THE MILL SITE
Multi-layer covering cap (1,5-1,6 m)Surface stabilisation by
horizontal and verticaldrain and geogrid (12,6 ha)
Μεντεστ⌡ κυτσ⌠ρ δρνφαλ ρενδσζερ α φελσζν αλαττι ϖζταρτ⌠κβα κιϕυτ⌠ττ σζεννψεζ⌡δσ ελτ⟨ϖολτ⟨σα χλϕ⟨β⌠λContaminated groundwater pumping out by deep and shallow groundwaterwells and continuous draniage trenches
max. 740 mBq/m2s
4000 mBq/m2s
600-800 mm/a
30-60 mm/a
Radon barrier
min. 200 yearsInfiltration barrierTP I.
- 1962-1980,1990-1997
- 100 ha- 15 768 kt tailings- 71,3 g/t U- 1 125 t UTP II.- 1981-1989- 59.3 ha- 4 599 kt tailings- 55.8 g/t U- 257 t U
RREMEDIATIONEMEDIATION OF THE TAILINGS PONDSOF THE TAILINGS PONDS
~20 Mt
After covering tailings pond I., natural background values are accepted
Long Long termterm changechange of of effectiveeffective dosedosecomponentscomponents inin PellPelléérd, 2000 rd, 2000 –– 2008.2008.
0,0
0,5
1,0
1,5
2,0
2,5
3,0
3,5
4,0
4,5
márc.00aug.00
jan.01
jún.01
nov.01
ápr.02
szept.02jan.03
jún.03
nov.03
ápr.04
szept.04febr.05
júl.05
dec.05máj.06
okt.06
márc.07aug.07
jan.08
Idı
Effec
tive d
ose,
mSv/y
Külsı gamma Rn-termék Aeroszol alfa Összes dózis
Terrestiral background Hun. average = 0,8 mSv/y
Population dose limit: nat. background +1 mSv/y
TREND!?Trend?
2000 2008
Ambient gamma Aerosol alpha Summa doseRn progeny
Decreasing of the effective doseduring the covering of the TPs
TTHEHE REMEDIATED TAILINGS PONDREMEDIATED TAILINGS POND
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 groundwater around 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 groundwater around 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
Shallow GW5-20 m
Deeper GW25-40 m
TDS
U~50 µg/l
GGROUNDWATERROUNDWATER CONTAMINATIONCONTAMINATION
Pellérd
Péc s e
r - Ba ch
Wasserbehandlungsbetrieb
I. Schlammteich
II. Schlammteich
SammlerschachtDekontaminierungs BrunneMonitoring BrunneDrainleitungRohrleitungsnetzWasserbehandlungsbetriebTrinkwasser Brunne
GW extraction wells: 15+12 piecesDeep dranage: 2.8 kmVolume of extracted water: ~ 0.43 Mm3+0.3 Mm3
Water treatment: pump and treat with lime milk.Sludge is deposited on WP3 (dry 3-4 kt/y).
Yearly operation cost: 800 000 US $ (~1.9 US $/m3)
TP2
TP1
GGROUNDWATERROUNDWATER RESTORATION SYSTEMRESTORATION SYSTEM
CONTROLLING OF THE COLLECTED DISCHARGECONTROLLING OF THE COLLECTED DISCHARGE
λmax.<2000 µS/cм
Limits: U<2 mg/lTDS<5 g/lRa<1.1 Bq/lV, m3/h ?
Vmax.=f(v, λmax, λ1,λ2)
v, λ1
λ2
Treated mine waterTreated and untreatedgroundwater
Receiverλ~1450 µS/cm
λ~1800 µS/cm
Discharge basin
pH
Volume of the discharged water through the Volume of the discharged water through the integrated system (2007) integrated system (2007)
Non-treated water(e.g. deeper GW,Northern mines)
0.52 Mm3
Treated groundwater0.30 Mm3
Treated mine water0.32 Mm3
Discharge point LimitsTDS: 5 g/lU: 2 mg/l
In the receiver:Sp. el. cond: 2 mS/cm
Ra: 1.1 Bq/l
TDS: 3.44 g/lU: 0.12 mg/lRa: 0.19 Bq/l
Receiver (Pécsi-víz)1.14 Mm3
Thank you for your attention!Thank you for your attention!