23 AUGUST 2017 DUST IN AGRICULTURE AIR QUALITY AND DUST 2 DUST IN - - PowerPoint PPT Presentation

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FARMERS MEETING - PETERSVILLE AGRICULTURE WORKING GROUP MEETING AIR QUALITY / DUST, GROUNDWATER, SURFACE WATER AGRICULTURE AND SURROUNDING LANDOWNERS 23 AUGUST 2017 DUST IN AGRICULTURE AIR QUALITY AND DUST 2 DUST IN AGRICULTURE RISK

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FARMERS MEETING - PETERSVILLE

AGRICULTURE WORKING GROUP MEETING AIR QUALITY / DUST, GROUNDWATER, SURFACE WATER AGRICULTURE AND SURROUNDING LANDOWNERS

23 AUGUST 2017

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2

AIR QUALITY AND DUST

DUST IN AGRICULTURE

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3 RISK ASSESSMENT

Dust Sources
Haul Roads
In pit activities
TSF Construction
Dust Modelling
Well below license conditions
DPC and EPA reviewed

previous modelling & set licence conditions

Maximum level at a receptor
ccurs when tailings dam

height increase construction

DUST IN AGRICULTURE

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4 LICENCE CONDITIONS

Summary of air quality compliance criteria

Substance Criteria Units Averaging Period Reference PM10 50 µg/m3 24 hoursa Hillside Mine ML Air NEPM PM2.5 25 µg/m3 24 hours Hillside Mine ML NEPM advisory reporting standard PM2.5 8c µg/m3 24 hours NEPM advisory reporting standard TSP 120 µg/m3 24 hours Hillside Mine ML TSP 90 µg/m3 12 months Hillside Mine ML TDDd 2 g/(m2 month) 30 days (for annual average) Hillside Mine ML TDD 4 g/(m2 month) 12 months Hillside Mine ML

DUST IN AGRICULTURE

TDD – Total Dust Deposited is most relevant to agriculture

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5 CONTROL MEASURES

Haul road material and

construction.

Minimise disturbed areas.
Progressively rehabilitate land.
Water trucks and sprays.
Modify operations – change mining
r dumping locations.
Risk management – predict high

risk conditions and plan operations accordingly.

Early warning monitoring and
perational adjustment.

DUST IN AGRICULTURE

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6 MONITORING

Compliance Monitoring:

Dust onto & off the site.
PM10 and TSP.
PM2.5 for one year to evaluate levels.
Dust deposition monitoring.

Early Warning Monitoring:

Additional operational monitoring

within the site close to sources for

perational management.
Informs operations of dust trends.
Alerts triggered.
Additional controls or changes to
peration.

DUST IN AGRICULTURE

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7 MONITORING PLAN

Monitoring network:

Focus on monitoring near

receptors (residences).

Measure concentrations of PM10,

TSP & PM2.5 and dust deposition.

Locations - considering prevailing

wind directions (including seasonal).

DUST IN AGRICULTURE

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8 DUST DEPOSITION GAUGES DUST IN AGRICULTURE

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9

GROUND WATER

GROUND WATER AND ADJACENT AGRICULTURE

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10

GROUNDWATER MANAGEMENT AND MONITORING PLAN

HYDROGEOLOGY

Groundwater occurs in fractured basement rocks - basement rock aquifer.
Basement rock aquifer fresh to partially weathered.
Overlain by saprolitic (weathered) zone clays – confining layer.
Overlain by Tertiary age sediments – unsaturated (no aquifer).
Covered by topsoil.
Rain falling on YP infiltrates through the soil.
Water that has moved past the root zone then sits on top of the saprolite

zone.

Then may infiltrate down into the formations over a long period of time,

eventually reaching the basement aquifer.

Basement groundwater is saline to hypersaline – not used by agriculture
Moves very slowly from west to east.

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11

GROUNDWATER MANAGEMENT AND MONITORING PLAN

GEOLOGICAL CROSS SECTION

Farmers get “first use” of rainfall

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12

GROUNDWATER MANAGEMENT AND MONITORING PLAN

HYDROGEOLOGY – BASEMENT AQUIFER WATER ELEVATIONS PRE-MINING

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13

GROUNDWATER MANAGEMENT AND MONTORING PLAN

OUTCOMES

Strategies:

calibrated basement ground water model;
ngoing calibration of the transient ground water model using data obtained

from groundwater monitoring;

ngoing calibration of the pit lake geochemistry and hydrogeological

models using data obtained from operational monitoring;

monitoring of process plant functions, including tank levels, flow rates,

pressures and fluid quantities;

groundwater monitoring – depth and quality

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14 HYDROGEOLOGY – MODELLED BASEMENT AQUIFER WATER ELEVATIONS AFTER 5 YEARS OF OPERATION

GROUNDWATER MANAGEMENT AND MONTORING PLAN

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15

GROUNDWATER MANAGEMENT AND MONITORING PLAN

DEFINITIONS

Parameters to be monitored:

Depth to water or standing water level (SWL) – in metres below

ground or a reference point.

SWL converted to water elevations AHD (approximate sea level).
Water quality – Salinity, pH, Calcium, Magnesium, Potassium,

Sodium, Sulphate, Chloride, Nitrate, Arsenic, Boron, Chromium, Cobalt, Copper, Iron, Manganese, Zinc, Antimony, Uranium, Total recoverable hydrocarbons (TRH) – 1 site only.

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16

GROUNDWATER MANAGEMENT AND MONITORING PLAN

LEADING GROUNDWATER CRITERIA

Baseline monitoring data – groundwater (to be updated prior to mining operations)

STATISTIC Chloride (mg/L) EC (µS/cm) pH

Diss. Arsenic
Diss. Boron

Diss. Cadmium

Diss. Copper
Diss. Zinc

Min 9200 30000 6.2 0.001 1.7 0.0002 0.001 0.002 Max 58000 150000 7.8 0.05 5.5 0.0045 2.8 0.44 Average 21500 63000 7.11 0.01 3.82 0.001 0.244 0.24 AV+ 2SD 47469 127589 5.43* 0.034 6.05 0.002 1.453 0.182

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17 PROPOSED MONITORING LOCATIONS

GROUNDWATER MANAGEMENT AND MONITORING PLAN Summary

No water table or unconfined aquifer
Basement aquifer confined by

saprolite – low permeability

Cone of depression of basement

aquifer only

Basement aquifer saline to

hypersaline – no agricultural use

Farmers get first use of rainfall
Dewatering of basement aquifer does

not impact available soil water

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18

SURFACE WATER

SUFACE WATER AND ADJACENT AGRICULTURE

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19

SURFACE WATER MANAGEMENT AND MONTORING PLAN

CURRENT LAND SURFACE - BASELINE CATCHMENT MODEL (1 IN A 100 YEAR FLOOD IN 6 HOURS)

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20

SURFACE WATER MANAGEMENT AND MONTORING PLAN

END OF MINE MODEL (1 IN A 100 YEAR FLOOD IN 6 HOURS)

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21

SURFACE WATER MANAGEMENT AND MONTORING PLAN

MANAGEMENT OF SURFACE WATER DURING OPERATIONS

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22 REPORTING

SURFACE WATER MANAGEMENT AND MONITORING PLAN

Key stakeholders will have access to relevant groundwater monitoring

data.

These include Rex Minerals, State and Local government agencies,

and the local community.

The Hillside Mine will report on the performance of the Surface Water

Management Plan in the Annual Compliance Report (ACR), provide regular updates to members of the HMCV consultation group, and made available for public information on the Rex Minerals website.

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