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Uranium Mining and Remediation Exchange Group Inc.

Presentation for the UMREG’15 Meeting at the WisSym2015 Symposium, August 31-September

3, 2015 in Bad Schlema, Germany.

Sustainable Remediation of the Mailuu Suu Uranium Legacy Tailings Sites.

Alex Jakubick1, Isakbek Torgoev2, Russel Edge3, Oleg Voitsekhovych4, Hagen Jung5, Peter

Waggitt6,

1) UMREG Inc., EU-Chapter, Volkertshausen, Germany, [email protected]

2) Institute of Geomechanics and Mining of the National Academy Sciences, Bishkek, Kyrgyz Republic

3) Office of Legacy Management, U.S. Department of Energy, Denver, USA

4) IAEA, Vienna, Austria

5) NUKEM Technologies, Germany

6) UMREG Inc., Darwin, NT, Australia

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Qualification of the Legacy Tailings Sites and Remediation Attempts. There were 23 Uranium Legacy Tailing sites left behind without orderly closure in the former Mailuu Suu mining and milling district, which was operational 1946 – 1968

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Qualification of the Legacy Tailings Sites and Previous Remediation Measures. In an analogy to the tailings storage facilities of comparable size in other parts of the world, the failure probability of the Mailuu Suu tailings facilities is in the range ~2 x (10-5 to 10-4) per annum [7]. It is safe to assume that the vulnerability of the Mailuu Suu tailings facilities is higher than suggested by the analogy because of the age of the facilities (pre 1968), poor siting, unsuitable facility designs, deficient closures and inadequate maintenance.

In addition, the area of Mailuu Suu is afflicted by various destructive geo-events that can induce failure

or weaken tailings dams/containments:

(a) The flow rates of the rivers eroding and transporting the tailings vary within a very wide range, e.g.

Aylampasay changes yearly from a harmless creek to a stream with throughput volumes of 500 –

800 m3 per second; while the change happens within hours;

(b) Mudflows and flooding in the valley occur regularly once/twice per year.

(c) Landslides in the valley are likely to occur every decade (or more frequently).

(d) Earthquakes occur within several decades.

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Qualification of the Legacy Tailings Sites and Previous Measures Remediation Measures Example of a Tailings Spill in 1950s. TSF #7, Mailuu Suu, April 1958. Approximately 600 thousands m3 of tailings spilled into the Mailuu Suu River

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Qualification of the Legacy Tailings Sites and Previous Measures Remediation Measures The tailings volumes stored at Mailuu Suu range from 2 000 to 600 000 thousand m3. Run-out distances in the range of approximately 100 to 500 meters (pending, besides volume, on the moisture content). Out of 23 tailings sites, the run out distance at 19 sites is sufficient to reach the MSR or Aylampasay, i.e. the transport agent. At 4 sites the run-out distances is insufficient to deliver the tailings to the transportation agents (river, mudflow). On the availability of a transport agent depends whether a tailings spill would cause an impact or not. Thus, the impact of a tailings spill depends crucially on the availability of a transport agent.

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Qualification of the Legacy Tailings Sites and Previous Measures Remediation Measures

By availability of tailings transportation agents within the run out distance of the legacy tailings storage

sites, the Mailuu Suu Uranium Legacy Tailings sites can be subdivided into three groups:

1. Sites in the domain of the Mailuu Suu River, MSR,

(a) downstream of the Karaagach River confluence (#17, #18, #9, #10, #19, #8, #20, #21 and #22),

and

(b) upstream of the Karaagach River (#5, #7 and #6&3).

2. Sites in the domain of the Aylampasay mudflows (#1, #2, #4, #13, #12 and #23).

3. Sites out of reach of rivers or mudflows (#11, #14, #15 and #16).

According to the present preliminary assessment the following tailings require relocation:

In the MSR domain (a) #18 and #8; (b) #5 and #7;

In the Aylampasay domain #2, #13 and #23.

More detailed remedial investigations and feasibility studies may identify additional Mailuu Suu tailings

as in need of relocation.

To substantiate the tailings relocation from the domain of transportation agents in the following we will analyse the consequences of a tailings spill along the MSR.

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Qualification of the Legacy Tailings Sites and Previous Measures Remediation Measures The Mailuu Suu and Aylampasay river stretches that would receive run-out tailings upon a potential tailings dam failure are marked with yellow colour. The tailings sites outside of reach of the Mailuu Suu River or Aylampasay mudflows are identified individually, #11, #14, #15 and #16. The boundary of the MSC on the MSR and on the Aylampasay River are marked red.

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Consequence Analysis of a Potential Tailings Spill at Mailuu Suu. Near-Field Consequences of a Potential Tailings Spill above the Community of Karaagach. The contamination sources: TSFs #5, #7 and the combined #6&3 - west-bank of the MSR between Kara Agach River at H: 1008 m and Sary-Bee River at H: 1041 m (Fig. 1). The river stretch within the run out distances of tailings is ~0.9 km. River slope dH: ~ 33m. High bed load fraction within the total sediment load of the river (>10%). Tendency to create sediment bars in the river. Chronic contamination from: Surface water discharges from TSFs #5 and #6&3. Subsurface discharges from #7. . Prime impact target in case of tailings spill: The community of Karaagach. Radiological dose equivalent of the inhabitants estimated by Vandenhove H. at al. [ ]. Use of river water for domestic purposes by the inhabitants of Karaagach. Therefore of particular importance the WHO-limit of 30 µg/L Uranium. Locally, U- concentration in the river after spill may increase above the WHO-limit by1 to 2 orders of magnitude.

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Consequence Analysis of a Potential Tailings Spill at Mailuu Suu. Near-Field Consequences of a Potential Tailings Spill for the Community of Karaagach. Sediment accumulation zone of ~20 ha in the Mailuu Suu River in front of the Karaagach settlement. Accumulation area for spilled tailings. Secondary contamination source seated directly in the river. Pot. U concentrations levels ~ tailings facility discharges. Economic impact: Elimination will require dredging, transportation and disposal of the accumulated tailings and contaminated sediments.

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Consequence Analysis of a Potential Tailings Spill into Mailuu Suu River (MSR). Near-Field Consequences of a Potential Tailings Spill above the Northern Mailuu Suu City (MSC).

The tailings storage sites #17, #18, #9, #10, #19, #8, #20, #21 and #22 north of Mailuu Suu City

(MSC) within the tailings run out distance of the MSR. The relevant river stretch: ~740 m long. The

river sloping dH: 10m, from H: 995 m to H: 985 m. The steady erosion endangers sites #18 and #8.

The first place of impact after tailings spill: The floodplains of northern MSC at the Kulminsay

confluence. After spill, the flood plains become covered by a tailings mud coating. A cleanup action

would be indispensable.

The “city stretch” of river between the N-Bridge (H: 962 m) and confluence of Aylampasay (H: 899 m)

~5.4 km long; river sloping dH: ~33m. In case of tailings spill accumulations in pointbars (and erosion

on the other bank.

MSR receives two tributaries from the W-bank (Ashpaz and Bedire Say) and three large tributaries

(and 9 intermittent tributaries) from the E- bank. Ashpaz contributes chronically small amounts of

tailings from TSF #16. Other tributaries have a diluting effect on the tailings load in the river.

U contamination of the river currently benign, in case of spill increase up to > 1 000 µg/ L. Beyond

environmental impact extensive clean-up of the pointbars will be required.

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Consequence Analysis of a Potential Tailings Spill into Mailuu Suu River (MSR). Near Field Consequences of a Potential Tailings Spill in the Aylampasay Valley.

The Aylampasay valley starts/ends in the southwestern suburbs of MSC at elevation of H: 934 m.

Tailings sites (#1, #2, #4, #13, #14 and #23) located on both sides of the valley.

The river stretch within range of the tailings run out distances ~ 2 km long. River sloping very steep,

dH: 115 m from H: 1050 m to H: 934m. Movement of mudflows very fast.

Unlike in the MSR domain, the prevailing erosion by abrasion.

In case of tailings spill, contamination of riverbed and floodplain but only limited exposure of humans, -

there are no permanent residents or significant agriculture in the valley.

However, the silty mudflow mixes readily with the finely ground tailings because of similar particle size

range. Thus, the volume of contaminated mud ends up larger than the volume of tailings making. The

unit costs of cleanup higher than in the MSR domain.

TSF #14 is located out of reach of the mudflows in a side valley of Aylampasay.

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TSF #23 is covered by two conventional industrial

waste dumps of the former ISOLIT factory.

After closure of U production, the light bulb

factory ISOLIT used the site for dumping their

conventional waste.

The relocation of the tailings #23 is needed to

protect the general public that frequently visits the

dumps to search for valuables, digging

dangerously deep into the dumps. The

radioactive warning sings indicating the buried

tailings are ignored by the public

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At the end of the Aylampasay valley, H: 934m the Aylampasay River runs across southern MSC to

enter, after a stretch of ~ 700 m, MSR at H: 899 m. The river sloping is dH: 35m. Prior to confluence

Aylampasay river passes by the tailings site #12 located on the flood plain. U concentration levels

after a tailings spill in the Aylampasay valley would be > 1 000 µg/ L.

Within a few meters downstream of the Aylampasay –MSR confluence a sediment accumulation zone

of > 0.93 km length begins in the MSR.

In case of tailings spill the southern Mailuu Suu accumulation zone would develop into a long-term

secondary tailings/contamination source for the population of southern Mailuu Suu city.

Aside from the radiological impact, an economic impact due to the clean up requirement - the tailings

and contaminated river sediments will have to be dredged out of the river, transported and deposited

outside of the MSR domain.

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Consequence Analysis of a Potential Tailings Spill into Mailuu Suu River (MSR). Near Field Consequences of a Potential Tailings Spill in the Aylampasay Valley. Near-field impact target of a pot. tailings spill in the Aylampasay Valley: Southern MSC

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Consequence Analysis of a Potential Tailings Spill into Mailuu Suu River (MSR). Consequences of Potential Contamination of the public water supply. The communal water supply of Mailuu Suu taken from the MSR at an elevation of H: 1135 m, i.e. above the legacy tailings sites that are between H: 1014 m to H: 1030 m, dH: >120 m.

Three, mostly buried, pipelines of 350 mm diameter supply 40 000 to 60 000 m3/day to Mailuu Suu

and northern Kek-Tash.

In case the pipeline and the Mailuu Suu public water supply become damaged and contaminated:

~17’000 inhabitants of MSC and ~2’ 600 inhabitants of Kek-Tash would be impacted.

Emergency water supply would be need .

Regular inspections and maintenance of the water supply pipelines are essential.

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Consequence Analysis of a Potential Tailings Spill into Mailuu Suu River (MSR). Far-Field Consequences of a Potential Tailings Spill downstream of Mailuu Suu City. 16.5 km long river stretch between the Aylampasay confluence (H: 899 m) and the MSR-Dam at Kyzyl-Kyya (H: 722 m). 10 tributaries (permanent and intermittent) in the stretch; dH: ~177 m; 4 major accumulation zones ~1 km, ~4.5 km, ~1.7 km and ~2.6 km long. The MSR dam at Kyzyl Kyya created a 2.6 km long river reservoir extending over >33 ha. In case of spill, the reservoir would function as a tailings trap. Tailings spill impact: Inhabitants of south Kek-Tash using river water for domestic purposes. Impact on agriculture: River water employed for irrigation of the fields (local practise of spreading moist canal mud on the fields). Fraction of the dissolved U and suspended tailings would escape via dam spillway.

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Consequence Analysis of a Potential Tailings Spill into Mailuu Suu River (MSR). Far-Field Consequences of a Potential Tailings Spill downstream of Mailuu Suu City. Regular monitoring, maintenance and inspections of the dam stability and state of the spillway needed. Recommendation: Prepare an Incident Management Program, Carrying out a peer review of the assessment of the present state of the dam and Institute routine Dam Safety and reservoir safety inspections. The MSR-Dam at Kyzyl Kyya, winter 2012:

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Consequence Analysis of a Potential Tailings Spill into Mailuu Suu River (MSR).

Consequences of Tailings Accumulation in the MSR-Dam Reservoir.

Approximately 4’800 inhabitants in the area of Karadzhigach (Kyzyl Kyya & close by settlements) rely

on the reservoir for their domestic water supply.

Additional impacts:

(1) Diversion of reservoir water into the “Left-bank Mailuu Suu Canal” supplying irrigation water to the

fields of Bostan and Kochkor-Ata. (2) Diversion via a pipeline across the MSR into a canal for use at

Kypchak Talaa. (3) Large scale tailings accumulation and contamination of the reservoir will require

special treatment during dredging, transportation and disposal of the silted-up reservoir.

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Consequence Analysis of a Potential Tailings Spill into Mailuu Suu River (MSR).

Potential Tailings Spill Impact Downstream of the MSR-Dam.

MSR-weir at Kypchak

Talaa (H: 674 m), ~8.5 km

downstream of the MSR-

Dam (H: 722m).

Elevation drop dH: 48 m in

the river stretch: 3

accumulation zones, ~370

m, ~320 m and ~270 m

long. River backed up

~160 m behind the weir.

Impact unlikely. Potential

targets are communities of

Kypchak Talaa and

Burgandy (use of river

water for domestic

purposes). Potential far-

field agricultural impact:

Diversion into the eastern

bank canal going to the

communities of Czek and

western bank canal to

Dzany-Aryk and Kichi

Byuogendyu.

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Consequence Analysis of a Potential Tailings Spill into Mailuu Suu River (MSR). The analysis shows: A tailings spill in the Mailuu Suu area would have far reaching consequences downstream MSR. Pending on the volume of the tailings spilled and attenuation capacity of the river, the MSR could carry the tailings as far as the MSR-Dam at Kyzyl Kyya, approximately 16.5 km downstream of the Aylampasay confluence. In such case, up to 20 - 24 thousand people who depend on the MSR water will require emergency water supply. Indirectly affected would be the communities using diverted MSR water for irrigation of their fields. (The impact of a spill may be discernable even at the MSR-weir of Kypchak Talaa, ~25 km downstream of the Aylampasay confluence). Recommendations: Monitoring the suspended tailings load and the places of sediment/tailings accumulation in the relevant parts of the Mailuu Suu River. The measurements are also needed to define the contamination baseline in the river. In case of tailings spill, data needed to serve as a reference level. Adopt a sustainable remediation for the hazardous legacy tailings storage sites of Mailuu Suu.

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Outline of a Sustainable Remedial Design and Preliminary Cost Estimate.

Destructive geo-events in the area of Mailuu Suu cannot be prevented and tailings failures on a time

scale of 200-1000 years will certainly occure.

The most pragmatic way of avoiding severe health and economic impacts due to potential tailings

spills is to relocate the hazardous tailings from the domains of the MSR and Aylampasay mudflows

into a final Tailings Disposal Facility (TDF) at a remote site without tailings transportation agents.

The TDF sould be designed to withstand the site-specific geo-hazards and follow the international

recommendations concerning the facility lifetime of 200 to 1000 years.

From the 23 Mailuu Suu legacy tailings sites only sites #11, #14, #15 and #16 are outside of reach of

transport agents.

Among these, the most suitable site for a final TDF is site #15. Geo-morphologically, the site is located

in a shallow dry valley above the level of landslides, approximately 10 km E of Mailuu Suu City. A

small volume of legacy tailings (47’000 m3) is stored at the lower end of the valley behind a ~4 m high

starter (pioneer) dam. Toward the upper end, the valley offers sufficient space for expansion.

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Outline of a Sustainable Remedial Design and Preliminary Cost Estimate. View of the legacy tailings storage site #15 and the potential expansion into a final Tailings Disposal

Site (TDS).

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Site #15 may be disturbed by an earthquake (just like any site in the area) but there are no

transportation agents to carry the tailings off the site.

The TDF can be and should be designed to resistant the earthquake magnitudes occurring in the area

(M=~5).

The volume of endangered tailings is ~ 500 000 to 800 000 m3. The capacity of #15 can be extended

to ~ 800 000 m3 (possibly up to 1 million m3).

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The sustainable Mailuu Suu Uranium legacy tailings remediation project would consist of :

(1) building of a construction road, approximately 10 km from Mailuu Suu City to site #15,

(2) design and construction of a TDF,

(3) relocation of the endangered tailings (nominally ~650 thousand m3).

A graded approach is recommended for implementation.

After construction of the road and TDF, the individual relocation projects, their prioritization, scheduling

and implementation, should follow the rules of diminishing environmental returns, i.e. the relocation of

tailings from an additional site should depend on the decrease of the improvement of the overall risk

achieved by the previous project.

Thus, the final volume of tailings relocated will directly depend on the improvement of the overall risk

in the domain.

Thus, the risk level to be aimed for would have to be specified prior to the individual projects.

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In a first approximation, we set the project costs, including 15% contingency, at~ 50 M Euro.

In case of this cost estimate, the submitted bids are likely to average ~45 M Euro.

Assume the possibility of 5% cost savings, the minimum costs of the project would be ~42.75 M Euro.

Counting with 15% cost increase, the maximum costs would be ~51.75 M Euro.

Thus, the required budget could be assumed as ~55 M Euro.

Based on previous experience with similar pprojects (EC Phare and DHMP) the range of the Mailuu

Suu project costs could be expected between 45 - 60 million Euros.

In spite of the high initial costs, the National Government and Donors would be well advised to opt for

a sustainable and fast remediation because:

(a) International experience shows that the direct costs of mitigation after tailings spills commonly

exceeds the cost estimates by 150 -300 % and,

(b) the indirect social and political costs of a tailings spill are usually approximately 10 x higher than

the costs of sustainable remediation [ ].

A sustainable remediation of the Mailuu Suu legacies tailings and prevention of the Mailuu Suu

River contamination is not only a prudent policy but also a cost-efficient solution to the legacy

tailings problem because a sustainable remediation is clearly more cost efficient than repeated

cheep remedial measures.

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Keep Tien Shan this way.

Thank you for your attention.

Any Questions ?

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Mailuu Suu #3

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