5. Management procedures

A range of routine measures will be used to manage and mitigate the effects of discharges of dust, odour or construction vehicle exhaust emissions during the Project. An adaptive approach to management of dust, including additional mitigation may be required in the event that:

• Monitoring indicates that abnormal discharges of dust are occurring; • Weather conditions are changing such that dust or odour discharges are more likely as determined using the Dust Risk Assessment; and / or • Complaints are received regarding discharges of dust, odour or construction vehicle exhaust emissions. If the available mitigation methods are unsuccessful in controlling discharges (i.e. dust and odour) that cause significant adverse effects on receptors beyond the Site boundary, the activities causing the discharge shall be suspended until adequate mitigation can be put in place.

5.1 Dust Risk Assessment

To provide guidance to the Environmental and Sustainability Manager and area supervisors (refer Section 9 of this AQ DWP) on implementing dust mitigation, this Project will use a Dust Risk Assessment (DRA) approach.

The DRA is described in Appendix C, and assigns a risk classification to each proposed activity with the potential to generate dust based on the scale of potential dust emissions and local environmental conditions (including sensitivity of adjacent activities and weather conditions).

As the dust risk is dependent on local environmental conditions, the dust risk associated with activities should be re-calculated as conditions change.

A “traffic light” indication of dust risk will be posted in each work area so that Project staff are aware of the dusk risk. The dust risk will be indicated as:

Low risk (green). Moderate risk (orange). High or extreme risk (red).

5.2 Dust mitigation measures

Dust management measures are specified for proposed enabling works activities in Table 5-1. Dust management measures may differ based on the dust risk of the activity calculated in accordance with the DRA in Appendix C.

The control measures specified for the calculated dust risk level should be employed in addition to the measures for all preceding levels–e.g. a medium risk activity requires application of measures applicable to the corresponding low risk activity as well as measures specified for medium risk.

Alternate methods may be employed after the effectiveness of those methods is demonstrated and this AQ DWP updated accordingly. The list of control methods is not exhaustive and additional methods may be found to be effective.

Table 5-1: Dust management procedures.

Dust source Dust risk level 1

Stockpiles Low

Vehicle movements (over sealed and unsealed surfaces) Medium

Low Control measure(s) Personal responsible

Store stockpiled material containing a high content of fine material indoors or undercover where practicable.

Outdoor uncovered stockpiling of spoil is to be limited to a volume of no more than 24 m 3

at any one time in an active construction zone (ACZ). This restriction does not apply outside ACZs, such as in construction support areas (CSAs).

Limit the height of any outdoor stockpiles to reduce wind entrainment (generally no greater than 3 m).

Orientate outdoor stockpiles to maximise wind sheltering as much as practicable. Keep active stockpiles damp at all times or bunker or cover stockpiles of fine materials. Dampen, cover or stabilise inactive stockpiles if they are producing visible dust emissions. Stabilise stockpiles using various means depending on the length of inactivity (e.g. soil binders if inactive for 28 days). Minimise drop heights and handling of stockpiled material to decrease potential for dust generation.

Bunker or cover stockpiles of fine, dry materials if stockpile is existing for prolonged periods (greater than 1 month). Maintain active stockpiles in damp condition with regular watering Dampen inactive stockpiles if they are producing visible dust emissions Utilise windbreak fences or temporary bunkers if they are producing visible dust.

Limit vehicle speeds to 20 km/h. Limit load sizes to avoid spillages. Cover loads of fine materials leaving or entering the site.

Minimise on-site travel distances through appropriate site layout and design. Minimise mud and dust track out from unsealed areas to sealed areas by using wheel cleaning facilities at site exits to sealed roads. Environmental Sustainability Manager or delegated person

Environmental Sustainability Manager or delegated person

Page 20 | Mt Eden Enabling Works 1 Dust risk levels for each activity will be dependent on environmental conditions and are to be calculated in accordance with the procedure described in Appendix C.

Dust source Dust risk level 1

Medium

Any outstanding demolition

Earth moving, mining and construction High

Low

Medium

High

Low

Page 21 | Mt Eden Enabling Works

Control measure(s) Personal responsible

Installation of wheel wash equipment (likely to be a hose). Sealed access routes are to be cleaned with a vacuum sweeper truck on a weekly basis (at a minimum). Any material identified to be tracked onto public roadways during regular inspections (or via notification from the public) is to cleaned with a vacuum sweeper truck.

If 1-hour average wind speeds are predicted in excess of 5 m/s, maintain unsealed surfaces in regular use in damp condition through surface watering (e.g. with water carts or fixed irrigation). Where a suitable water supply is not available for surface watering, synthetic dust suppressants may be used as an alternative. The use of recycled oil-based suppressants is expressly prohibited.

Maintain regularly used unsealed road surfaces in damp condition through surface watering in all wind conditions.

As required water sprays or fogging systems are used to dampen material to avoid dust generation.

Only wet cutting of concrete should be undertaken. Any breaking of concrete should be done under wet conditions (such as a water spray or fog directed at where the breaking is occurring).

Dust from the removal of plaster board is controlled by wetting the plaster board as it is broken up. Dust from knocking down and breaking up of blockwork or concrete, and from the removal of rubble will be controlled using water sprays or fogging systems directed onto the activity during dry and windy weather.

Limit the extent of excavation, mining and material handling activities in exposed areas carried out during dry and/or windy conditions as far as practicable. Limit drop heights of material during handling, including from any conveyor transfer points. Stabilise exposed areas not required for construction, access or parking, along with completed fill and spoil areas as soon as practicable.

Environmental Sustainability Manager or delegated person

Environmental Sustainability Manager or delegated person

Dust source

Loading and unloading of dry material

Blasting

Crushing (concrete and basalt)

Unpaved surfaces (including roads and yard areas)

Piling Dust risk level 1

Control measure(s)

Medium and High

Medium

Medium

High

Medium and High

Low

Low and Medium

Maintain dry surfaces of active earthworks and mining areas in damp condition. This should include pre-watering of active surfaces, prior to excavation and mining allowing enough time for moisture to penetrate the soil. Remove excavated spoil from site on a regular basis.

Maintain surfaces of active earthworks areas in damp condition during dry weather. This should include pre-watering of earthworks surfaces, prior to excavation allowing enough time for moisture to penetrate the soil.

Limit loading or unloading during windy conditions that cause dust to be emitted beyond the site boundary. Cover loads of fine materials.

Blasting is to be carried out in accordance with dust management measures Blasting Management Plan Topsoil and loose material overlying the rock shall be removed prior to blasting. If the rock and adjacent material is dry, dampen with water where practicable.

Use a fog canon on the area that is being blasted during the blast

Only crushers fitted with water sprays or fogging systems are be used and those systems are to be operated at all times when crushing occurs. Where practicable, the crusher plant is to be located to minimise the potential for wind to transport dust off-site (towards downwind off-site sensitive activities in particular).

Limit the amount of exposed surfaces as much as possible. Use water sprays or watering trucks to dampen dry exposed surfaces. Stabilise cleared areas not required for construction, access or for parking if liable to cause excessive dust during windy conditions. Methods may include placing metal or other coarse material on surfaces.

All spoil to be placed in a pre-identified stockpile location and removed from site as soon as possible. Any spilt material to be cleaned up immediately.

Page 22 | Mt Eden Enabling Works

Personal responsible

Environmental Sustainability Manager or delegated person

Environmental Sustainability Manager or delegated person

Environmental Sustainability Manager or delegated person

Environmental Sustainability Manager or delegated person

Environmental Sustainability Manager or delegated person

Dust source

Cement silo

Rock drilling

Miscellaneous Dust risk level 1

All dust risk levels

Medium and High Control measure(s)

Cement silos should be fitted and operated with a level alarm and pressure relief valves to ensure it is not over filled. Cement silos should be fitted and operated with a filtration system as a dust management mechanism.

Drills used on rock or concrete in exposed areas should be fitted with dust suppression mechanisms where practicable.

All dust risk levels

Ensure sufficient water is available for dust sprays on-site. Taking account of daily of weather forecast wind speed and wind direction, and the condition of any excavated spoil (such as its dampness) before commencing an operation that has a high wind potential. Installing wind fences where practicable and appropriate. Effectiveness is greatest where fencing is perpendicular to the prevailing northeast and southwest winds with porosity of about 50%. Maintenance of surface moisture content: Watering or wet suppression is used to dampen dry or dusty exposed areas. Personal responsible

Environmental Sustainability Manager or delegated person

Environmental Sustainability Manager or delegated person

Environmental Sustainability Manager or delegated person

Page 23 | Mt Eden Enabling Works

5.2.1. Operation of dust control equipment

Information will be sourced from the dust control equipment supplier on the following:

Procedures for equipment inspection (including timeframes for regular inspections), maintenance, monitoring and recording, including baghouses, pressure relief valves, high level alarms and dust suppression mechanisms such as fog canons or sprays.

5.2.2. Equipment malfunction

If construction equipment fails and causes accidental dust discharges, it will be shut-down immediately and the fault repaired and tested prior to being allowed to continue operation.

If equipment associated with dust control fails (such as a baghouse) the activities reliant on the equipment will be suspended until the fault can be repaired.

The location, duration and time of any dust discharge caused by equipment failure will be recorded in the Air Quality Log (log sheet template provided in Appendix E).

5.3 Review of dust mitigation

When site operators are alerted to a potential off-site dust nuisance through any of the monitoring techniques described in Section 6 of this AQ DWP, or as a result of a complaint from a third party, the Site Supervisor will immediately undertake a review of site activities to determine the source of the dust and implement further mitigation measures as required in order to reduce the dust generation to acceptable levels. As appropriate the Site Supervisor will notify the Environmental and Sustainability Manager.

In general, the additional mitigation will be those measures set out in Table 5.1.

Once the additional mitigation has been implemented the Site Supervisor will review the monitoring data to ensure that it has been effective.

5.3.1. Sources of information

The following are locations where information necessary for determining the Dust Risk Level and general dust control can be obtained:

Site Specific monitoring web site where TSP and meteorological data can be accessed (to be established); and Met Service: http://www.metservice.com/towns-cities/auckland/auckland-central MetVUW North Island forecast charts: http://metvuw.co.nz/forecast/.

5.4 Odour control during contaminated material handling

Odour may be emitted if contaminated soil is encountered during the excavation works, depending on the nature of the contamination. This section of the AQ DWP sets out the mitigation required by CRL designation condition 59.3(g) for minimising any potential for odour if contaminated material is encountered.

Odour emissions will be monitored in accordance with Section 6.6 of this AQ DWP during the excavation of contaminated material and the following techniques considered if necessary:

Limiting the time that the odorous material in the excavation is exposed; Removing excavated odorous material from site as quickly as possible in covered trucks; and The use of odour masking agents, chemical counteractants or digestive deodorant sprays.

If significant odour is detected and the odorous material cannot be removed quickly and odour masking agents, chemical counteractants or digestive deodorant sprays are not immediately available, the odorous material shall be covered with uncontaminated soil or other suitable material to suppress odour emissions, and work in that area suspended until suitable mitigation measures can be put in place.

5.5 Control of vehicle exhaust emissions

The following key actions shall be carried out to minimise emissions from vehicle exhausts:

All construction machinery used on the site will be maintained at least in accordance with manufacturers’ requirements; Where excessive exhaust smoke is identified from any construction vehicle that vehicle will be serviced as soon as is practicable and taken out of use until such maintenance has been completed; and Unless warm-up or turbo maintenance procedures require it, construction vehicles will not be left idling while parked or unattended.

5.6 Dust contingency measures

In the event of significant long-term, unavoidable dust emissions, that results in verified complaints of dust inside buildings, the contractor will implement the following contingency measures, dependent on the nature of the complaint:

Link Alliance will arrange for routine commercial cleaning of properties that are affected by adverse effects of dust.