LAMP RESIDUE MANAGEMENT PLAN AND PERMANENT DISPOSAL FACILITY
All chemical and mineral processing plants produce residues which are either reused or disposed of as wastes. The Lynas Advanced Materials Plant (LAMP) is no exception. Our residues are not wastes - they have tremendous potential as safe commercial products, as described below.
The Lynas residue management plan is clear, focused and in line with internationally accepted principles of residue management. The residue management plan approved by the Malaysian regulatory authorities is being implemented under their guidance with the participation of established national and international research organizations. Lynas is confident that with its clear corporate residue management policy, and systematic engagements with all product stakeholders, the best principles in residue management "from cradle to cradle" are being realized.
Although Lynas is required to plan and site a permanent disposal facility (PDF) as an additional assurance in dealing with Lynas residues, the success of our commercialization program to date has reduced the likelihood that a PDF will be required.
REUSING LAMP'S RESIDUES
The LAMP in Gebeng, Kuantan produces two solid residues, the Neutralization Underflow Residue (NUF) and the Water Leached Purification Residue (WLP). The NUF is a Magnesium Rich Gypsum and has been proven to be non-toxic, non-carcinogenic, non-ecotoxic and non-radioactive. Its magnesium rich properties and other chemical properties can be used to condition poor agricultural soil, and to rejuvenate and rehabilitate unproductive and depleted land.
The WLP residue, although classified as a radioactive material, has the same radioactivity level as the feedstock material used in the LAMP process (about 6 Bq/g of Th). This material is classified as very low level radioactive material. The LAMP operation does not enhance or alter the natural radioactivity. By way of example, material with similar levels of radioactivity can be used in roadbase material in the United Kingdom.
Interestingly, WLP is also an iron phosphogypsum with chemical properties that compliment NUF for the same agricultural purposes. The formulation of soil conditioners using WLP, NUF and inert filler materials has been proven through extensive research to be non-radioactive, non-toxic, and non-carcinogenic. The AELB has acknowledged that the formulated soil conditioner is not a radioactive material. During product development and commercialization, Lynas adhered strictly to all the guidelines provided by the regulatory authorities (including the DOE and the AELB) in ensuring that the products developed are both safe for people and safe for the environment.
The potential use of Lynas residues as safe commercial products is vast and unlimited. Every year, Lynas invests around 0.5% of its gross income on research to look for new and improved options to reduce and reuse the residues on a commercial scale. In addition Lynas has allocated another 0.5% of its income on other supporting research and will continue to invest substantially in the coming years. Commercial reuse is the preferred option. Permanent storage is not the preferred option.
ADDITIONAL ASSURANCE FROM A PERMANENT DISPOSAL FACILITY (PDF)
A PDF will always be the last choice in any residue management strategy because it is an unproductive long term use of the residues and of the land. Lynas subscribes to this strategy but at the same time realizes that an assurance must be given to the public that should the need arise for a PDF, Lynas is prepared for it.
Since the LAMP started its operations under a Temporary Operating License in 2012, Lynas has assured the Malaysian government and the public of the following:
In 2014, the IAEA Report of the International Post-Review Mission on the Radiation Safety Aspects of the Operation of a Rare Earth Processing Facility and Assessment of the Implementation of the 2011 Mission Recommendations on the LAMP concluded that the risk from the LAMP operation is intrinsically low.
All evidence related to the safety, health and environmental status and performance of the LAMP is routinely reported and scrutinized by the relevant authorities. Real-time and online environmental monitoring data are available to the public on the internet and on the Lynas, AELB and DOE websites. All monitoring data has shown that the LAMP operation, including residue management, has had no negative effect on the public and the environment.
The regulator approved Lynas PDF plan can now be substantiated with real information and experiences gathered from the use of the current on-site residue storage facility (RSF) to accurately design and construct a future PDF, if the need arises. However, it is worth restating that the preferred option under the Lynas residue management plan is commercial reuse, and not permanent storage.
Lynas' commitment to safety and the environment includes a security deposit, held by the AELB, as an additional assurance of our commitment to residue management. We have deposited many millions of US dollars with the AELB, in an amount sufficient for a PDF, if the need arises.
The Mt Weld deposit and its overlying sediments have formed at or near the surface in a strongly oxidising, supergene geochemical environment. Both gangue minerals (waste) and ore minerals are chemically stable and do not undergo any appreciable weathering or alteration when exposed to surface conditions. There are no sulphides or other minerals capable of producing acidic run-off water or otherwise harmful products that occur in the deposit or overburden.
The major rare earth minerals are secondary phosphates with variable calcium contents, which have been precipitated directly from groundwater under near-surface temperature and pressure conditions.
The gangue minerals are dominated by hydrated iron oxides, mostly occurring as very soft, fine grained, porous, friable siltstone. Manganese oxides, secondary silica, secondary calcium-aluminium phosphates and residual apatite and ilmenite are minor components of the ore.
The Mt Weld processing plant produces a residue called tailings. The tailings comprise the rare earth minerals that are not recovered into the rare earth concentrate; the gangue minerals and water. There is no chemical change to the minerals as a result of the processing plant. The majority of the water is recovered or evaporated, with some remaining moisture retained with the solids. An extensive development program over the past 5 years has enabled the recovered water to be retreated and re-used.
In accordance with accepted practice, the processing plant tailings are safely stored in tailings storage facilities (TSFs) within the Mt Weld mining leases. Additional TSFs will be constructed over the life of the mine. The TSFs are engineered impoundment structures that are designed for permanent on-site storage, constructed and operated in accordance with approvals from Department of Mines and Petroleum (DMP) and the Department of Environment Regulation (DER).
The rare earth ores at Mt Weld contain low levels of thorium (Th) and uranium (U) and therefore, there are low levels of radiation present in the tailings. The tailings solids contain approximately 500 ppm ThO2 and 30 ppm U3O8, which is equivalent to a radiation specific activity of 2 Bq/g. This is lower than the ore which contains on an average 750 ppm ThO2 and 30 ppm of U3O8 which is equivalent to a radiation specific activity of 3 Bq/g.
The long term plan for the TSFs is documented in Mine Closure Plan which is approved by DMP and updated on a periodic basis. The key steps are:
View from NE corner, solar drying of beached tailings
Water run-off and decant tower in the SW corner