Groundwater Management Bird in Hand Gold Project TERRAMIN AUSTRALIA - PowerPoint PPT Presentation

Groundwater Management Bird in Hand Gold Project TERRAMIN AUSTRALIA LIMITED SLIDE No. 1

LEGISLATIVE PROCESS ➤ Mine is approved under Mining Act and any other permit it requires (EPA, DEWNR, SafeWork) ➤ Mine is subject to Natural Resources Management Act ➤ Department advised that Project must comply with objectives of Water Allocation Plan ➤ S. 128 - Authorised Use of Water ➤ Used by projects – ag, civil, mining ➤ Terramin proposing to have a neutral groundwater balance ➤ MAR testwork program in 2018 – to be agreed with DPC and DEWNR

HOW IS INFORMATION COLLECTED ➤ Taking water levels and field measurements (pH, TDS, etc) ➤ Sending water samples to the laboratory ➤ Drilling monitoring bores (piezometers) ➤ Equipping bores with pressure transducers, or dipping manually ➤ Live monitoring for quality and level can be set with trigger levels/alarms ➤ Same style system proposed for monitoring construction and operations

GROUNDWATER BASELINE ➤ Groundwater census 2014-2017 ➤ Water levels ➤ Water quality ➤ Springs and groundwater dependent ecosystems ➤ Investigation bores drilled and pump tested in 2014 ➤ Understanding of system on a local and regional scale ➤ Groundwater model constructed based on over 250 assays, thousands of levels, 60 drill holes, and aquifer properties

MODELLING AND CALIBRATIONS Transient Calibration – Seasonal groundwater decline (m) due to irrigation pumping 6628-10199 385 380 RSWL 375 370 365 2/03/14 18/09/14 6/04/15 23/10/15 10/05/16 26/11/16 Woodside 420 6628-8937 415 RSWL 410 405 400 2/03/14 18/09/14 6/04/15 23/10/15 10/05/16 26/11/16 410 6628-8945 405 BIHGP RSWL 400 395 390 380 6628-18637 RSWL 370 360

GEOLOGY - AQUIFERS, FRACTURES AND SALINITY

PROBE DRILLING 4. 4. Water moves around the grouted shell following natural flow paths

MANAGED AQUIFER RECHARGE

INVERBRACKIE CREEK – BASED ON CDM SMITH CONCEPTUAL IMAGE

INVERBRACKIE CREEK – BASED ON CDM SMITH CONCEPTUAL IMAGE Depressurisation bore Reinjection Bores

REINJECTION CONCEPTS Water level Not to scale

REINJECTION CONCEPTS ~10-15 metres < Mine Irrigation bores > Not to scale

GROUNDWATER MONITORING NETWORK CONCEPTUAL ➤ Additional monitoring wells to be placed between receptors and reinjection: ➤ Private wells ➤ Inverbrackie Creek ➤ Dawesley Creek catchment ➤ High frequency monitoring of : ---- Reinjection bore network ➤ Groundwater seepage & quality ---- Monitoring bore network ➤ Groundwater levels & quality

REINJECTION SYSTEM ➤ Dept. Environment Water and Natural Resources Well Drainage Permits ➤ All with license conditions ➤ Cannot impact water quality of existing bores ➤ Cannot take away existing users access to water ➤ Pipelines along existing fence lines and existing cleared land

LIVE MONITORING ➤ Live and public – web hosted ➤ Monitoring bores between reinjection bores and irrigation bores ➤ Monitoring will compare against mine water flows and levels - ➤ Irrigation bores ➤ Native vegetation area ➤ Inverbrackie Creek ➤ Monitoring includes salinity

SIMILAR PROJECTS ➤ Ernest Henry, QLD - Grouting Parameters Ernest Henry Bird in Hand Inflows (l/s) 75-100 1-38L/s Pressure (kPa) 3500 1400 Temperature ( o C) 49 20 ➤ Ophthalmia Dam, WA - MAR To maintain the hydrological regimes of groundwater and surface water so that existing and potential uses, including ecosystem maintenance, are protected. Works within Pilbara Groundwater Allocation Plan ➤ Broken Hill MAR investigation ➤ Used to supplement town’s water supply during drought

Proposed Outcomes and Measurement Criteria No adverse impact to the supply or quality of water by the mining operations to existing users and water dependant ecosystems TERRAMIN AUSTRALIA LIMITED SLIDE No. 19

No adverse impact to the supply or quality of water by the mining operations to existing users and water dependant ecosystems Measurement Criteria – How should we demonstrate this? Suggestions ► Monitor water levels and quality in new monitoring wells (“piezometers”) – live and publically available - Located between reinjection wells and existing users ► Monitor water levels and quality in existing private bores (agreed frequency at PEPR) ► Monitor pressure of injection system at new monitoring wells - Located between reinjection wells and existing users ► Monitor and report water volumes extracted and reinjected - public ► Comply and report against section 128 license conditions - public ► Comply and report against DEWNR drainage permits - public ► Annual audit and report against DEWNR s. 128 and drainage permits - public TERRAMIN AUSTRALIA LIMITED SLIDE No. 20

Discussion -  Comments on Outcome Criteria?  Any questions from the Groundwater Assessment?  Any questions on IGS Peer Review or CDM Smith Peer Review? TERRAMIN AUSTRALIA LIMITED SLIDE No. 21

SURFACE WATER MANAGEMENT Bird in Hand Gold Project

BASELINE ENVIRONMENT ➤ Desktop Study – looked at DEWNR and EPA reports ➤ Samples obtained over 3 years from Inverbrackie Creek, tributaries and dams (>370 samples) ➤ Before-After, Control- Impact (BACI) approach – from ANZECC (Aus/NZ Environment Conservation Council) ➤ Springs identified from water samples – chloride mass balance

Samples taken using the BACI (Before After / Control Impact) method Macroinvertebrate + habitat work – Habitat assessment using AusRivas – Australian River Assessment System

OUTCOME OF BASELINE STUDIES ➤ EPA studies: 2008 – 2016 rated between very poor and poor ➤ ➤ Water turbid, enriched with nutrients. ➤ Weedy shrubs over introduced grasses ➤ AC Environmental Studies ➤ Waterway highly disturbed ➤ Metals: higher than freshwater trigger levels at some sites: Arsenic, cadmium, copper, lead and zinc ➤ High levels of ammonia and nitrates further downstream ➤ Higher salinity after rainfall ➤ Macroinvertebrate: Low diversity ➤ Nutrients are increasing algal growth and biological oxygen demand ➤ OPPORTUNITY: With appropriate mitigation and management practises the health of the stream could be restored and maintained.

SITE CATCHMENT MAP

SURFACE WATER MANAGEMENT STRATEGY Proposed Outcome: No contamination of natural water drainage systems, streams and rivers, groundwater, land and soils occurs either on or off site ➤ Maintain existing flow into creek systems ➤ Measurement Criteria: ➤ Water quality – any water flowing offsite must be better than upstream or EPA Water Quality Guidelines ➤ Apply individual source treatments to manage pollutants – where required ➤ Water Sensitive Urban Design strategies ➤ 30 000 sedges planted this year ➤ System will provide a benefit and require no maintenance post mine closure