Welcome and agenda Description Time 1 Welcome 7.00 pm 2 - PowerPoint PPT Presentation

TERRAMIN AUSTRALIA LIMITED Bird in Hand Gold Project Woodside Community Consultative Committee Water Technical Reference Group Meeting Wednesday 26 th July 2017 Woodside Bowling Club

Welcome and agenda Description Time 1 Welcome 7.00 pm 2 Orientation: how we came to be here 7. 05 pm • Community engagement opportunities • Progressing the WCCC 3 Review of water studies 7.20 pm 4 Thank you, next meeting and close 9.00pm 2

Community consultation In the past, Terramin has conducted: • public meetings • one on one meetings and small group meetings • drop in session This community input has been used in Terramin’s work to date in putting together its mining proposal 3

Opportunities for the local community to be involved • The WCCC has been established to promote a community based approach to broad community engagement rather than a Terramin led process • special focus groups will be held by Terramin to directly address particular community groups and respect unique circumstances such as ‘some members of the community have more to lose / gain than others and this must be recognised and taken into account’ (comment made at the first WCCC meeting 3 rd July 2017) • drop in sessions may be held that could include presentations from the mining regulator and other stakeholders • community members will always have the right to contact Terramin or the mining regulator directly as well as other stakeholders like their local elected members or relevant Ministers of government. 4

Moving forward Handover • Christine Charles is MD of a company called Design for Growth and is working with Terramin • Christine along with Katy and Matt who you know, will be the ‘go to’ people within Terramin WCCC governance working party • Terms of Reference • Independent Chair and secretariat WCCC meeting • Complete introduction to WCCC core group members • Special item CSIRO survey • Reports from WCCC governance working party • Key issue (s) for consideration 5

WCCC Water Technical Reference Group (TRG) • Learn more about the ground water assessment report for the Bird in Hand Gold Project, and the independent review • Understand the purpose of the report • Ask questions • Provide comments and other input • Identify challenges, concerns and priorities • Identify opportunities 6

Water issues brought forward from last WCCC meeting • A closer look at the data collected • An understanding of the assumptions used in the Assessment Report • An understanding of the modelling with a special focus on its reliability • An understanding of the potential for salinity migration in the catchment • An understanding of the likely volume of any water that may be released into the mine, plans for any reinjection for any of this water and methods of any proposed reinjection • An understanding of water allocation requirements, water planning and / or water purchase that may be required 7

Groundwater Technical Reference Group Tonight’s format  Groundwater  Existing conditions and Modelling – Jason van den Akker Hydrogeologist  Underground water management strategies  Grouting: what and how? – Katy Fechner Terramin  Depressurisation and Reinjection – Matt Daniel Terramin  Groundwater Monitoring Networks – Matt Daniel Terramin  Question and Answer Session TERRAMIN AUSTRALIA LIMITED SLIDE No. 8

Approach Conceptual model  Information gathering (>3 years)  Develop conceptual groundwater model  Build computer model  History matching  Groundwater predictions Computer model  Independent review of conceptual & computer models TERRAMIN AUSTRALIA LIMITED SLIDE No. 9

Information gathering  Anecdotal evidence (1930’s & 50’s)  Groundwater levels (regional flow pattern)  Groundwater pumping  Groundwater recharge (rainfall)  Groundwater & surface water interactions  Drilling & aquifer testing to understand aquifer permeability TERRAMIN AUSTRALIA LIMITED SLIDE No. 10

Conceptual groundwater model – Regional scale Groundwater flow direction Project site TERRAMIN AUSTRALIA LIMITED SLIDE No. 11

Conceptual groundwater model – Local scale NW SE Historic BiH mine Marble Fractures Proposed mine decline  Aquifer characterised based on  >60 exploration holes  5 investigation bores  Several aquifer tests TERRAMIN AUSTRALIA LIMITED SLIDE No. 12

Computer model  Groundwater models are computer models of groundwater flow systems.  The model was developed to:  Represent the current state of groundwater  Predict the rate of groundwater inflows  Assess groundwater impacts Project site  Evaluate water management options TERRAMIN AUSTRALIA LIMITED SLIDE No. 13

Computer model construction  900,000 model cells (5 to 50 m 3 in size)  Assign aquifer (rock thickness, dip, faults)  Assign aquifer properties such as permeability  Regional groundwater flow into & out of model (catchments)  Add private bores (pumping)  Add rainfall recharge  Add Inverbrackie Creek TERRAMIN AUSTRALIA LIMITED SLIDE No. 14

History matching  Model Calibration – matching historic observations to model predictions  The model needs to replicate:  Current groundwater flow pattern – 35 observation bores  Seasonal groundwater level change due to pumping – 28 observation bores  The results of the 6 day pumping test – 20 observation bores  Historic mine dewatering – Mine managers records & Government reports used to validate model TERRAMIN AUSTRALIA LIMITED SLIDE No. 15

History matching to observations at 28 bores Project site TERRAMIN AUSTRALIA LIMITED SLIDE No. 16

History Match – Simulation of regional groundwater flow pattern Project site TERRAMIN AUSTRALIA LIMITED SLIDE No. 17

Model review process  Groundwater modelling guidelines  120 compliance criteria  Iterative process looking at  Planning  Conceptual model  Design and construction  Calibration & sensitivity analysis  Predictions of impacts  Model is fit for purpose  Government will conduct its own review TERRAMIN AUSTRALIA LIMITED SLIDE No. 18

Model uncertainty  Robustness of the model is based on the amount of information available to inform construction  Limited info = low confidence (need to make assumptions)  More info = higher confidence (less assumptions)  This model has evolved over 3 years  Sensitivity analysis:  What parameters is the model sensitive to?  How does altering these parameters influence the model predictions of impacts? TERRAMIN AUSTRALIA LIMITED SLIDE No. 19

Uncertainty  Worst case  Interception of water bearing fault (beyond 60 L/s)  Different grouting effectiveness (reduce inflows to 4 to 12 L/s)  Increase aquifer permeability (+7 L/s)  Reduce rainfall recharge TERRAMIN AUSTRALIA LIMITED SLIDE No. 20

Water Water Allocation Plan Allocation • Located in Western Mt Lofty Ranges Prescribed Water Resource Area - September 2013. Unlimited GW use prior to then. Now 940ML/year. • The rules of the WAP are designed to protect the groundwater system and the rights of existing users to a sustainable groundwater supply. • Terramin will protect the groundwater and existing users through the same rules. • Terramin have not started exploring options with the department to clarify water licensing on inflows and reinjection • WAP binds Terramin to same “no impact” rules TERRAMIN AUSTRALIA LIMITED SLIDE No. 21

Water Allocation Plan Principles TERRAMIN AUSTRALIA LIMITED SLIDE No. 22

Law - Proposed Outcome Criteria What we are proposing to be monitored against  All aspects of the project have outcome statements like these  Provide the basis for all design and monitoring  WATER “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. 23

Groundwater Management Strategy How can we manage groundwater impacts? 1. UNDERSTAND – existing geology and hydrogeology 2. DESIGN – mine plan to avoid water bearing zones 3. PROBE – ground conditions ahead of mining to know what’s ahead 4. GROUT – Grouting for groundwater control 5. REPLACE – reinject groundwater back into the aquifer around the mine TERRAMIN AUSTRALIA LIMITED SLIDE No. 24

1. UNDERSTAND and 2. DESIGN to avoid fracture zones NW SW Historic BiH mine  >60 drillholes  Fracture mapping  Targeted Marble investigation Fractures in the Proposed mine decline bores “Hanging wall”  Several aquifer tests  Creates a 3D model of geology TERRAMIN AUSTRALIA LIMITED SLIDE No. 25

3. PROBE and 4. GROUT process  Pre-excavation grouting is used to stop or reduce groundwater inflow into the mine  Cement is pumped into the fractures approximately 2-5m around the mine void prior to progressing the tunnel  The need to grout is determined by the results of the probe drilling and conditions encountered during mining process  Constantly builds on info from steps 1 and 2 TERRAMIN AUSTRALIA LIMITED SLIDE No. 26

3. PROBE drilling and 4. GROUT process  Why?  Identify old mine shafts, geology check, rock strength for tunnel, water bearing fractures ahead of tunneling TERRAMIN AUSTRALIA LIMITED SLIDE No. 27