1. Landfills – the next mining boom? David Gamble GHD National Service Line Leader, Waste Management

2. Waste 2012 – Landfills - the next mining boom? Overview of Presentation Reasons for mining waste Issues to be considered Logistics and other challenges Overseas examples Future overseas projects Landfill mining possibilities in Australia Opportunities to address existing environmental issues Outlook for landfill mining in Australia? Conclusions

3. Waste 2012 – Landfills - the next mining boom? Reasons for mining waste 1. Recovery and re-use of landfill cover materials. 2. Upgrade landfill design – lining of previous unlined landfills. 3. Better utilization of landfill airspace through greater compaction. 4. Redevelopment of valuable land. 5. Resource recovery from previous landfilled waste.

4. Waste 2012 – Landfills - the next mining boom? Issues to be considered 1.The composition of waste landfilled and the market value of material being sought. 2.The likely efficiency of the proposed resource recovery process when applied to the content of the materials being sought. 3.The quality requirements of the products (ie acceptable level of contamination). 4.The likely environmental and health impacts of the process (asbestos? hazardous materials)? 5.Logistics – where to do the processing, stormwater and leachate management during mining and refilling, landfill gas management 6.Ways of managing the amenity issues – noise, dust, odour, traffic, gas 7.Community expectations about long term operation of site – mining, processing and refilling over long period of time (instead of site closure)

5. Waste 2012 – Landfills - the next mining boom? Logistics and other challenges Logistics – is the site sufficiently large for processing plant, stockpiles of waste to be processed, stockpiles of processed recovered materials awaiting export, stockpiles of waste to be re- landfilled, stormwater and leachate management ponds etc? Extent of processing needed to minimise contamination of the end product – e.g. to ensure that “clean fill” does not have asbestos and foreign objects in it Contamination of products (plastics, metals) rendering them useless – need for washing plants may add significant costs and complexity to site operations

6. Waste 2012 – Landfills - the next mining boom? Overseas examples of landfill mining Barrie, Canada long-term waste excavation, screening and re- compaction 0.5 million m3 of material mined mining of unlined cells and placement into new lined cells Reuse of fines for daily cover and engineering purposes Perdido MSW landfill in Escambia Country, Florida Upgrade landfill to meet environmental regulations Re-use of landfill airspace. Removing sources of landfill gas and leachate Reclaiming soils for on-site reuse Waste - to – Energy

7. Waste 2012 – Landfills - the next mining boom? Planned overseas projects Taiwan landfills – The largest planned landfill mining program in the world. EPA Taiwan plans to excavate all of the country’s 404 landfills and use the material for energy production (26 large scale incinerators). Other materials such as glass, metal and flammables will be recovered and rocks and pebbles will be reused for road paving. Remo Milieubeheer landfill, Belgium – expect to use 45% of the landfill’s contents for recovery of materials, electricity generation and carbon dioxide reduction. George Town landfill, Grand Cayman – convert excavated materials to electricity and address long standing environmental issues (visual, odour, air and noise etc).

8. Waste 2012 – Landfills - the next mining boom? Landfill mining possibilities in Australia Rural site in NSW – The site is short of landfill cover material, and the main aim of mining is to recover soil for future use. The age of the waste and the shallow nature of the landfilling operations suggests that the putrescible component has already stabilised. Metropolitan site – The aim of this project is to recover known materials for reprocessing (old cars and scrap metal and green wastes), and to extend the landfill life. After mining, the areas would likely be lined (they are currently unlined), and the cells refilled to final levels with residual wastes (wastes remaining after processing of non putrescible wastes). Rural site in NSW – The site will be landfilled with baled and wrapped waste, which will have most of it’s putrescible component removed by separate organics collection. Metals will have been removed prior to baling. One day, the landfilled bales of plastics and paper may be worth recovering for energy production.

9. Waste 2012 – Landfills - the next mining boom? Case Study 1 Mining can be used on remote sites to recover airspace and provide future daily cover (if needed) – metal recovery may be viable

10. Waste 2012 – Landfills - the next mining boom? Case Study 2 Need to consider the overall staging of the landfilling operations when planning mining activities Have to “finish off’ areas of the landfill to minimise stormwater management issues - mining is difficult in such areas Mining is an integral part of the landfilling and rehabilitation sequence Possibility of mono-filling resources for future recovery

11. Waste 2012 – Landfills - the next mining boom? Opportunities to address existing environmental issues Existing situation: Informal recycling and resource recovery – scavenging occurs on the landfill sites. Unsuitability of existing landfill locations in some countries – relocation of waste or stabilisation of landform is needed Landfill mining can: Recover valuable materials from these landfills. Address landfill safety environmental issues. e.g. landslips are common after heavy rains in landfill in Philippines and many other countries. Make sites suitable for other uses, or rehabilitation/reforestation (if too steep etc)

12. Waste 2012 – Landfills - the next mining boom? Outlook for landfill mining in Australia? 1.Major landfills Landfill gas production and extraction will still be occurring in 30-50 years time at some sites Some sites are relatively close to residential areas Significant odour problems if waste disturbed (high putrescible waste content) Site profiles (heights/slopes) make mining of waste challenging and dangerous at some sites May become attractive if future technology enables recovered plastics to be used for future energy production

13. Waste 2012 – Landfills - the next mining boom? Outlook for landfill mining in Australia? 2. Landfills in rural areas Areas of shallow and unlined landfill cells with poor capping well suited to mining Less landfill gas issues due to lower putrescible waste content Generally isolated from residential properties Gentle slopes and low heights of landfill mass in “old” areas makes logistics easier May be high concentrations of metals and other materials worth recovering in old rural landfills

14. Waste 2012 – Landfills - the next mining boom? Conclusions Landfill mining can be used to re-create landfill airspace, address existing environmental issues, obtain scarce cover materials and provide suitable areas for future land development Rural landfills may be more suitable for landfill mining than major landfills A rigorous Cost-benefit Analysis may need to be undertaken before proceeding on a major landfill mining program On-site trials may be needed to “prove” that the landfill mining process will be economically viable Logistics and environmental management issues need to be carefully considered and managed during the process There is huge potential for landfill mining to be undertaken in developing countries to address legacy issues from past practices Future energy demands combined with innovative extraction and processing technologies might make mining of landfills containing plastics more attractive in the future.

15. Waste 2012 – Landfills - the next mining boom? www.ghd.com