The 12th International Conference on Environmental ... - Events

Abstracts Session 43
radioactivity was generally less than 0.5 Bq L -1 as recommended for drinking water. Only one water supply from a local spring to
a village exceeded the recommended limit for alpha radioactivity in drinking water with 1.12 Bq L -1 . <strong>The</strong> overall assessment of
water radioactivity in this uranium mining region indicated that water resources were not significantly contaminated by the historic
radium and uranium mining. Nevertheless, acid mine waters from Urgeiriça and Bica mines still require treatment to prevent dispersal
of the acid and radionuclides into the aquifer.
SESSION 43 - URANIUM MINING AND MILLING SITES ER
1) DESIGN IMPROVEMENTS AND ALARA AT U.S. URANIUM IN SITU RECOVERY FACILITIES - 16415
Steven Brown, SENES (USA)
In the last few years, there has been a significant increase in the demand for Uranium as historical inventories have been consumed
and new reactor orders are being placed. Numerous mineralized properties around the world are being evaluated for Uranium
recovery and new mining / milling projects are being evaluated and developed . Ore bodies which are considered uneconomical
to mine by conventional methods such as tunneling or open pits, can be candidates for non-conventional recovery techniques,
involving considerably less capital expenditure. Technologies such as Uranium In Situ Leaching / In Situ Recovery (ISL / ISR -
also referred to as solution mining), have enabled commercial scale mining and milling of relatively small ore pockets of lower
grade, and are expected to make a significant contribution to overall world wide uranium supplies over the next ten years. Commercial
size solution mining production facilities have operated in the US since the mid 1970s.
However, current designs are expected to result in less radiological wastes and emissions relative to these first generation plants
(which were designed, constructed and operated through the 1980s). <strong>The</strong>se early designs typically used alkaline leach chemistries
in situ including use of ammonium carbonate which resulted in groundwater restoration challenges, open to air recovery vessels
and high temperature calcining systems for final product drying vs the zero emmisionsvaccum dryers as typically used today.
Improved containment, automation and instrumentation control and use of vacuum dryers in the design of current generation plants
are expected to reduce production of secondary waste byproduct material, reduce Radon emisions and reduce potential for employee
exposure to uranium concentrate aerosols at the back end of the milling process.
2) RADIONUCLIDE TRANSFER FROM URANIUM MINE WATER TREATMENT PONDS TO VEGETATION - 16260
Fernando P. Carvalho, Instituto Tecnológico e Nuclear (Portugal);
João M. Oliveira, Magarida Malta, Nuclear and Technological Institute (Portugal)
Sulphuric acid was used in large amounts for in situ leaching and static leaching of uranium ore in uranium mines at Portugal.
<strong>The</strong> production of uranium ceased years ago and at several mines water treatment plants still are in operation to neutralize pH of
acid mine waters and to remove radioactivity before releasing treated water into surface water streams. Sludge from water treatment
is decanted and deposited in ponds which, as wet areas, develop spontaneous vegetation and attract biota such as insects and
birds. Distribution of uranium series radionuclides in these ponds was investigated in the mud, overlaying water, and spontaneous
vegetation. Radionuclide concentrations in the sludge reach about 41 000 Bq kg-1 for 238U, 1 700 Bq kg-1 for 226Ra, and 1 200 Bq
kg-1 for 210 Bq. This paper reports on the bioavailability of radionuclides from the sludge to spontaneous vegetation growing in the
ponds area, such as grass, rush and reeds, and discusses potential transfer of these radionuclides into the food chain.
3) COMPLETION OF THE SOUTH ALLIGATOR VALLEY REMEDIATION, NORTHERN TERRITORY,
AUSTRALIA - 16198
Peter Waggitt, IAEA (Austria); Mike Fawcett, Fawcett Minesite Rehabilitation Services (Australia)
13 uranium mines operated in the South Alligator Valley of Australias Northern Territory between 1953 and 1963. At the end
of operations the mines, and associated infrastructure, were simply abandoned. As this activity preceded environmental legislation
by about 15 years there was no remediation.
In the 1980s it was decided that the whole area should become an extension of the adjacent World Heritage, Kakadu National
Park. As a result the Commonwealth Government made an inventory of the abandoned mines and associated facilities in 1986. This
established the size and scope of the liability and formed the framework for a possible future remediation project. <strong>The</strong> initial program
for the reduction of physical and radiological hazards at each of the identified sites was formulated in 1989 and the works
took place from 1990 to 1992. But even at this time, as throughout much of the valleys history, little attention was being paid to
the long term hopes and plans of the traditional land owners.
<strong>The</strong> Aboriginal Traditional Owners, the Gunlom Land Trust, were granted freehold Native Title to the area in 1996. <strong>The</strong>y
immediately leased the land back to the Commonwealth Government so it would remain a part of Kakadu National Park, but under
joint management. One condition of the lease required that all evidence of former mining activity be remediated by 2015.
<strong>The</strong> consultation, and subsequent planning processes, for a final remediation program began in 1997. A plan was agreed in
2004 and, after funding was granted in 2005, works implementation commenced in 2007. An earlier paper described the planning
and consultation stages, experience involving the cleaning up of remnant uranium mill tailings and other mining residues; and the
successful implementation of the initial remediation works. This paper deals with the final planning and design processes to complete
the remediation works, which is due in 2009. <strong>The</strong> issues of final containment design and long term stewardship are addressed
in the paper as well as some comments on lessons learned through the life of the project.
4) GUNNAR URANIUM MINE ENVIRONMENTAL REMEDIATION - NORTHERN SASKATCHEWAN - 16102
Joseph Muldoon, Laurier Schramm, Saskatchewan Research Council (Canada)
Thirty-six now-abandoned uranium mine and mill sites were developed and operated in Northern Saskatchewan, Canada, from
approximately 1957 through 1964. During their operating lifetimes these mines produced large quantities of ore and tailings. <strong>The</strong>
Gunnar Mine is located on the shores of Lake Athabasca, the 22nd largest lake in the world. <strong>The</strong> Gunnar mine (open pit and underground)
produced over 5 million tonnes of uranium ore and nearly 4.4 million tonnes of mine tailings. <strong>The</strong>re is an estimated
2,710,700 m3 of waste rock that abuts the shores of Lake Athabasca. After closure in the 1960‘s, the Gunnar site along with all of
the other uranium mine and mill sites were abandoned with little remediation and no reclamation being done. <strong>The</strong> governments of
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