Original EA Amendment

To assess the potential impact of Heritage Minerals Project to groundwater and the operation of the

Upper Mundic Gully TSF, Table 36 provides a summary of expected outcomes for each catchment

associated with groundwater flows. This builds on the post mining conceptual source-pathway-receptor

summary anticipated changes to the hydrogeological system and modelled groundwater inflow changes

developed by GHD (2017) and RGI (2010 and 2011) groundwater catchment mapping and simulated

groundwater flows.

Table 36. Potential Scenarios for Groundwater/ Seepage Flows

Sub catchment Heritage Minerals activities

Potential Scenarios

Arnolds Gully

Reactivation of Horse Paddock

Improved surface water drainage reducing infiltration and

Waste Rock Dump

subsequent poor-quality seepage via careful placement,

compaction, shaping and capping of ARD waste rock by

placement of overlying NAF waste rock.

Potential for seepage water quality to further degrade in

short term (reduced recharge), draining and expressing to

Arnolds Sump.

Likely reduced poor quality seepage to Arnolds sump in

medium to long term (reduced recharge).

Nelsons Gully

Reactivation of Horse Paddock

Improved surface water drainage reducing infiltration and

Waste Rock Dump

subsequent poor-quality seepage via careful placement,

compaction, shaping and capping by placement of

overlying NAF waste rock.

Potential for seepage water quality to further degrade in

short term (reduced recharge), draining and expressing to

Nelsons sump.

Likely reduced poor quality seepage volumes to Nelsons

sump in medium to long term (reduced recharge).

Mining of 2 Mill tailings

Improved surface water drainage reducing infiltration and

subsequent poor-quality seepage via removal of ARD

generating mine waste (tailings).

Potential for seepage water quality to improve in short

term (ARD source removal), draining and expressing to

Nelsons Sump.

Likely reduced poor-quality seepage volumes to Nelsons

sump in medium to long term (reduced recharge).

No. 2 Mill

Reactivation of Horse Paddock

Improved surface water drainage reducing infiltration and

Waste Rock Dump

subsequent poor-quality seepage via careful placement,

compaction, shaping and capping by placement of

overlying NAF waste rock.

Potential for seepage water quality to further degrade in

short term (reduced recharge), draining and expressing to

2 Mill sumps.

122

Wulguru Technical Services Pty Ltd – Supporting Information to Amend an Environmental Authority

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