ANGAS PROCESSING FACILITY MISCELLANEOUS PURPOSES LICENSE APPLICATION - PDF document

APPENDIX S16 LANDFILL TRIAL CAP PRESENTATION ANGAS PROCESSING FACILITY MISCELLANEOUS PURPOSES LICENSE APPLICATION 2019/0826 ABN | 67 062 576 238 Unit 7 / 202-208 Glen Osmond Road | Fullarton SA 5063

Angas Zinc Mine Terramin Australia • Southern Waste Phytocap • Soil Moisture Deficit Modelling • Soil Moisture Probes in trial Cap … A Comparison 201 6 TERRAMIN AUSTRALIA LIMITED SLIDE No. 1

Southern Waste Phytocap v AZM proposed ET cover system for the AZM TSF  Southern Waste Depot (SWD) Phytocap part of AACAP Trials  Located at McLaren Vale, South Australia  Angas Zinc Mine Conceptual Phytocap Design  Located at Strathalbyn, South Australia  AZM is 38km west of SWD Conceptual image from Southern Waste AACAP trial paper – Waste Management Association of Australia http://www.wmaa.asn.au/lib/pdf/01_about/121120_WMAA_AACAP_final2.pdf TERRAMIN AUSTRALIA LIMITED SLIDE No. 2

McLaren Vale and Strathalbyn A Climatic Comparison  Average monthly maximum temperature for Noarlunga and Strathalbyn mirror each other  Strathalbyn has a slightly lower average minimum temperature compared to Noarlunga  McLaren Vale has a higher average monthly rainfall between April and August  Average monthly rainfall over the Summer months (September – March) is largely the same for both sites (McLaren Vale and Strathalbyn)  Overall, McLaren Vale has a higher average annual rainfall than Strathalbyn  Potential Evapotranspiration (PET) at AZM remains higher on average than McLaren Vale year round, especially between November and March. Potential Max Temp (mean) Min Temp (mean) Rainfall (mean) Evapotranspiration (mean) McLaren McLaren McLaren McLaren Strathalbyn Strathalbyn Strathalbyn Strathalbyn Vale Vale Vale Vale 21.7 21.3 12.7 9.5 517.8 490.7 1163.2 1497 TERRAMIN AUSTRALIA LIMITED SLIDE No. 3

Temp, Rainfall and ET Comparison TERRAMIN AUSTRALIA LIMITED SLIDE No. 4

Phytocap Design: A Comparison  AZM includes a capilliary AZM SWD break layer made of crushed cement (or similar) to reduce the potential for rising salts Landfill and through the profile (from Foundation Compacted tailings compacted clay tailings) Capillary break  AZM moisture storage layer layer 300mm - is 700mm deeper than SWD  AZM total depth is an Moisture Storage additional 1000mm Layer 1500mm 800mm compared to SWD Topsoil 100mm 100mm Total depth of layer 1900mm 900mm TERRAMIN AUSTRALIA LIMITED SLIDE No. 5

Landfill Phytocap Trial  Landfill cap constructed in November 2013  1600mm moisture storage layer with similar characteristics to proposed Phytocap materials  No capillary break layer  No topsoil  Soil Capitance (moisture) and EC probes installed at 10cm, 40cm, 70cm, 90cm, 110cm, 130cm, 160cm and 180cm  Direct seeded with native grass – 10% cover  No maintenance (watering, weeding, hare control TERRAMIN AUSTRALIA LIMITED SLIDE No. 6

Results to date Moisture and Rainfall  After rainfall, moisture levels increase in the shallowest sections where the probes are located  Moisture remains steady in the deeper sections year around  In periods of low to no rainfall, EC remains stable, as EC will only mobilise with water, as can be seen in the “waves” TERRAMIN AUSTRALIA LIMITED SLIDE No. 7

Moisture and Rainfall 200 40 180 35 160 30 140 25 Soil Moisture (%) 120 Rainfall (mm) 100 20 80 15 60 10 40 5 20 0 0 10 40 70 110 130 160 180 Rainfall (mm) TERRAMIN AUSTRALIA LIMITED SLIDE No. 8

Results to date EC and Rainfall  EC increases directly after a large rainfall event in the first year  As moisture/rainfall permeates deeper into the soil, EC increases at the next deeper probe (forming waves in the graph).  See specifically May/June 1013 rainfall event  EC increases (caused by an increase in rainfall/moisture) is identifiable by the waves down to approximately the 130cm level, but doesn’t permeate the 160-180cm probes  After the probes have been installed for approximately 12 months, the EC and moisture in the lower levels (40cm and deeper) are stabilising (November 2014 onwards) TERRAMIN AUSTRALIA LIMITED SLIDE No. 9

EC and Rainfall 1000 40.0 900 35.0 800 30.0 700 25.0 600 500 20.0 400 15.0 300 10.0 200 5.0 100 0 10 40 70 110 130 160 180 Rainfall (mm) TERRAMIN AUSTRALIA LIMITED SLIDE No. 10

EC and Rainfall – “Waves” TERRAMIN AUSTRALIA LIMITED SLIDE No. 11

Soil Moisture Deficit Modelling  Utilising Penman-Monteith methodology, Soil Moisture Deficits modelled using water balances and then modified by van den Akker (2011) using capitance probes  Models likely recharge through soil profiles Penman-Monteith Equation TERRAMIN AUSTRALIA LIMITED SLIDE No. 12

SMD modelling developed by -  characteristics of soil, including particle size distribution to determine the field capacity of the soil type  crop coefficient of the vegetation which is present in the trial Obtaining site specific meteorological data including rainfall and evaporation  Potential Evaporation from the Pan Evaporation  root depth of the established vegetation (“root zone”)  Averaging the root zone moisture probe data (10cm, 40cm and 70cm probes) TERRAMIN AUSTRALIA LIMITED SLIDE No. 13

Equation Parameters  Crop Coefficient for evapotranspiration - Crop Coef 0.85 Guidelines for computing crop water requirements - FAO Irrigation and drainage paper 56, UN, 1998 Pan Coef 1  The soil moisture deficit was determined Root zone 0.7 to be 84 (root zone * field capacity)  Recharge/drainage cannot occur unless the SMD is below 0. Field Capacity 120 SMD (mm) 84 TERRAMIN AUSTRALIA LIMITED SLIDE No. 14

SMD model v Real Root Zone data 100 -5% 0% 80 5% 60 10% Moisture Content % 15% mm/m 40 20% 20 25% 30% Soil is in deficit 0 Soil is draining 35% SMD Average_root zone -20 40% Nov 2013 Jan 2014 Mar 2014 May 2014 Jul 2014 Sep 2014 Nov 2014 Jan 2015 Mar 2015 May 2015 Jul 2015 Sep 2015 Nov 2015 Jan 2016 Mar 2016 May 2016 TERRAMIN AUSTRALIA LIMITED SLIDE No. 15

Real data supports Modelling  Graph demonstrates that  recharge/drainage did not occur from November 2013 to June 2016, as the real data has matched the predicted modelling.  Gives Terramin confidence that the Phytocap (designed by AECOM), will be successful in limiting net percolation into the tailings, as the ET cap is designed to be a minimum of 1.5m deep.  The modelling and real data supports AECOM’s hypothesis that <1mm recharge/year is likely to occur through the TSF ET cap, once constructed. TERRAMIN AUSTRALIA LIMITED SLIDE No. 16

Sensitivity Analysis  What happens when we only look at 10cm root depth?  What about 130cm root depth? 20.0 18% Soil Moisture Deficit (mm/m) 15.0 16% 10.0 Moisture content % 14% 5.0 Soil is in deficit 12% Soil is draining 10% -5.0 -10.0 8% -15.0 6% -20.0 4% -25.0 2% -30.0 -35.0 0% Nov-2013 Nov-2014 Nov-2015 Jan-2014 Mar-2014 May-2014 Jul-2014 Sep-2014 Jan-2015 Mar-2015 May-2015 Jul-2015 Sep-2015 Jan-2016 Mar-2016 May-2016 SMD Moisture Content - 10cm Graph shows sensitivity analysis results of 10cm root depth probe data and SMD modelling for 10cm root depth. SMD of 15 TERRAMIN AUSTRALIA LIMITED SLIDE No. 17

AECOM - Conclusions  “Given the successful implementation of phytocap water balance modelling and soil characteristic moisture assessment undertaken for AZM TSF and the successful development and trial of the Southern Waste Depot landfill phytocap at McLaren Vale (35km west of AZM) for climatic conditions (higher average rainfall and lower evapotranspiration) slightly less favourable than AZM (Strathalbyn), URS and Terramin are confident that the Proposed Phytocap Conceptual Design for AZM will perform as modelled in the Angas Zinc Mine TSF Proposed Phytocap Conceptual Design ” (URS, 2014). TERRAMIN AUSTRALIA LIMITED SLIDE No. 18

SMD Next Steps  Analyse the impact of large scale rain events on infiltration  Include an impact event water runoff coefficient and slope component to the equation – Q = CiA  Determine the possibility of further moisture probe calibration by aligning laboratory moisture content results (analysed by a NATA accredited laboratory when installed)  Develop construction plan for 30 x 30m life size model replicating proposed phytocap TERRAMIN AUSTRALIA LIMITED SLIDE No. 19