Environmental Management


8.1. Erosion and Sediment Control



The Hunter River floodplain in the East Maitland/Morpeth area comprises alluvial sediments consisting of deep, fertile soils overlying river sands at depths exceeding 10 to 20 metres. Previous drilling data reveals that the sediments vary from fine sandy and clayey silt to coarser sand with some clay horizons. The top 300mm of soil cover has been extensively cultivated.

The erosion hazard on this site is very minimal due to the low slopes and negligible erosion is visible within the quarry site. Any sediment laden water collected over the site is directed to the pit sump. Clean water will be diverted around the disturbed area where possible and will not contribute to the dirty water system. Progressive rehabilitation will follow behind mining on finished slopes and will assist in the reduction of sediment entrained water.


8.2. Surface Water Management

The soil operation does not impact on the flow of the Hunter River. In the case of ponded rain water within the excavation, this water will be drained to sumps and subsequently pumped onto unworked sections of the site as irrigation. The water, once it has filtered through the sand substrata to the water table is not likely to contaminate the river.

Water collected in the sump of the manure handling area will be used to suppress dust on the manure stockpiles and will not be used outside the area capped by an impervious layer of compacted clay, thereby avoiding infiltration into the groundwater system. Note; no manure has been imported onto the site as yet.


8.3. Groundwater Monitoring

From the limited available data within the vicinity of the site, the water in the Hunter River and neighbouring bores is generally not suitable for drinking but may be used for irrigation and stock watering. Potential sources of contamination from the site are the animal manure and green waste blended on the site, as well as fuel and other hydrocarbons used by quarry equipment.

There are three groundwater boreholes established on the site (as shown in Figure Two) that were monitored during the previous reporting period. Anolytes were chosen based on contaminants that would be most likely be found in this rural setting due to the use of fertilisers, pesticides and petroleum hydrocarbons and also those that might be found in the groundwater due to contamination from site activities. These were then compared with the ANZECC Guidelines (Ref. 3) for a 90% protection trigger values for a moderately disturbed system.

The previous results indicated that both nitrogen and phosphorus was present in levels that could cause stress on the ecosystem. These results are to be expected in such a highly cultivated area. E. Coli was identified in two of the groundwater samples and also the Hunter River.

Groundwater monitoring was undertaken during the reporting period, see Appendix E. These results show that most of the anolytes are below the detection limit or have not changed. Total nitrogen and phosphorus have steadily decreased from the initial pre commencement period March 2008, except for GW 1 which has risen, see attached graphs. Phosphorus will be reviewed during the next period.


8.4. Air Pollution

Dust generation will be minimised by grading, topdressing and watering of internal roads. Truck loads will be covered and a water cart will be used to reduce dust generation in other areas on the site where required. During adverse wind conditions it is anticipated that dust levels will be similar to or less than those generated by ploughing and other agricultural activities in the area. Regular visual inspections will allow operators to identify periods when dust generation is evident and undertake preventative action.

The reporting period was characterised by very low activity and therefore no air quality issues were apparent and no complaints were received.
 
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8.5. Noise

The proposed operation is not expected to have any adverse impacts on the surrounding landowners. Blending and screening is positioned away from nearby residents (see Figure Two). The following noise controls are implemented on the site;

·         Mobile equipment is operated below embankments and within excavations as much as possible.
·         Equipment is maintained in good order and regularly serviced.
·         Equipment will be used only as required.
·         Hours of operation shall be limited to 7am to 6pm Monday to Saturday and 8am to6om on Sundays and Public Holidays.
·         Speed restrictions and adherence to traffic management procedures.

An earth wall was constructed along the south eastern boundary near the gates and adjacent to the main works area and haul road to assist with noise attenuation.

No noise complaints were received during the reporting period.


8.6. Odour

To reduce the odour from manure, the manure stockpiles will be maintained at no more than two truckloads at any one time. Odour will be regularly monitored at the site boundaries, and any complaints recorded along with prevailing weather conditions and the approximate amount of manure on-site at the time of complaint.

As importation of manure has not commenced, the mitigation of odours has not been required.


8.7. Acid Sulphate Soil Management

Analysis undertaken previously indicates the sediments proposed for extraction at Pitnacree are not potential or actual acid sulphate soils. The lack of sulphur availability, free supply of oxygen and the aquatic nature of the environment would largely preclude the sediments from possessing acid sulphate potential.

Regular monitoring of groundwater quality and excavated areas will be undertaken to identify the risk of acid sulphate soil (ASS) exposure. Some factors that may indicate the presence of ASS are:

·         Low pH in the groundwater and groundwater (<4.0 pH units)
·         Presence of sulphurous odour in soil or water.
·         unusually clear or milky green drain water coming from or within the site.
·         extensive iron stains on drain surfaces or stream banks,
·         pale yellow surface encrustations or nodules (jarosite) on soil clods or on spoil heaps left exposed after dredging or excavation.
·         augured soil or excavated pits indicating any pale yellow or orange red iron oxide posits in fissures and old root channels or iron oxide mottling.
·         blue-grey, blue-green or grey waterlogged soils which smell of rotten egg gas;
·         black, organic gels in drains, pH less than 4, with a slightly oily appearance

Soils will be analysed for ASS potential should the above factors indicate a risk of contamination. Appropriate measures for remediation will be undertaken if the soils are found to be ASS.

In the absence of extraction activities, no ASS management was required.


8.8. Rehabilitation and Landscaping

On removal of soil from the freehold site it is intended to rehabilitate the site progressively to a state consistent with its earlier land use. It is evident from exploratory drilling that there is considerable depth of suitable soil remaining after excavation to support cultivation. The final contours will blend into the existing rural landscape and be revegetated with suitable pastoral grass species.

Soils on the alluvial flats are of a class I to II land capability indicating they are suitable for intensive cropping and grazing. Suitable pastures for grazing are ideally a mixture of grasses and legumes. A cover crop of oats, rye grasses or similar species would be sown initially to establish ground cover to prevent erosion of newly rehabilitated are as followed by perennial species. These areas would be fertilised regularly to maintain vigour as soil test results indicate. Newly sown pasture areas would only be lightly grazed in the first season or if dry, spell them to allow perennial species to seed down. Additional sowing of perennial species would be undertaken where groundcover is inadequate.

Some planting of native trees and shrubs may be undertaken to form windbreaks and create a visual buffer around the site (see Table 11 from the EIS for species list).

No rehabilitation of the site was undertaken during the reporting period as no extraction was undertaken.

 
8.9. Weed Control Plan

As is common on riverside lands, some species of noxious weeds were prevalent on the site. The property has now been manually depleted of castor oil plant and Cestrum infestations with spot spraying over the reporting period using Grazon Extra at a rate recommended by the directions of use. All spraying was completed by a neighbouring contractor.

The control of weeds is an ongoing process. Regular ‘spot’ spraying should be adequate to maintain weed numbers.