Mandalong Southern Extension Project Blasting Vibration

Mandalong Southern Extension Project

Blasting

Vibration and Airblast Assessment

Report Number 630.10123.00820%R2

10 March 2014

Centennial Mandalong Pty Ltd

PO BOX 1000

Toronto NSW 2283

Version: Revision 0

Centennial Mandalong Pty Ltd Mandalong Southern Extension Project Blasting Vibration and Airblast Assessment

Report Number 630.10123.00820%R2 10 March 2014

Revision 0 Page 2

SLR Consulting Australia Pty Ltd

Mandalong Southern Extension Project

Blasting

PREPARED BY:

SLR Consulting Australia Pty Ltd ABN 29 001 584 612

10 Kings Road New Lambton NSW 2305 Australia

(PO Box 447 New Lambton NSW 2305 Australia)

T: 61 2 4037 3200 F: 61 2 4037 3201

E: [email protected] www.slrconsulting.com

This report has been prepared by SLR Consulting Australia Pty Ltd

with all reasonable skill, care and diligence, and taking account of the

manpower and resources devoted to it by agreement with the Client.

Information reported herein is based on the interpretation of data collected,

which has been accepted in good faith as being accurate and valid.

This report is for the exclusive use of Centennial Mandalong Pty Ltd.

No warranties or guarantees are expressed or should be inferred by any third parties.

This report may not be relied upon by other parties without written consent from SLR Consulting.

SLR Consulting disclaims any responsibility to the Client and others in respect of any matters outside the agreed scope of the work.

DOCUMENT CONTROL

Reference Status Date Prepared Checked Authorised

630.10123.000820%R2 Revision 0 10 March 2014 John Cotterill Katie Teyhan John Cotterill



Revision 0 Page 3

Executive Summary


SLR Consulting Australia Pty Ltd (SLR) has been commissioned by Centennial Mandalong Pty Ltd to undertake an assessment of potential blasting during construction of surface infrastructure for the Mandalong Southern Extension Project (the Project).

The Project involves the extension of Mandalong Mine’s existing underground mining operations toward the south into the area covered by Exploration Licence 6317 (EL6317), along with the utilisation of existing and proposed infrastructure integral to the mining operation in terms of coal delivery, handling and transport.

There may be a requirement for construction blasting to occur where rock is encountered along some sections of the access road to, and at the site of, the proposed Mandalong South Surface Site (MSSS). The aim of this Blasting Assessment was to assess the potential ground vibration and airblast impacts associated with the Project on surrounding sensitive receptors ie private residences, electricity transmission lines and Aboriginal heritage sites. The scope for this Blasting Assessment has been designed to address the Director General’s Requirements (DGR’s) and Government agency and Council comments with regard to the assessment of blasting emissions.

The Australian and New Zealand Environmental and Conservation Council (ANZECC) guidelines have been used as the basis of this assessment. Site laws for vibration and airblast were developed from widely accepted generic formulas. The site laws were then utilised to determine blast design parameters which are predicted to not unduly impact sensitive receptors.

The approach of this assessment was to determine the limiting factors to the blast design for the Project with the aim of achieving the relevant criteria outlined in Section 5.1.

Table 4 contains the results of the allowable maximum instantaneous charge (MIC) calculations based on the site laws developed for ground vibration and airblast predictions (presented in Section 5.2). The distances presented in the tables are the closest distance that blasting could occur to the identified receptors.

In relation to potential impact at residences, the most restrictive situation, in terms of allowable MIC, is at Location R16 where an MIC of 144 kg would apply due to airblast limitations.

If blasting is required in close proximity to the transmission line towers each blast will need to be designed on a case by case basis. Calculations show that an MIC of 329 kg will be required if blasting occurs at the nearest point of the MSSS to the transmission lines.

In relation to Aboriginal heritage sites if blasting is required in close proximity to the stone arrangement of the western side of the access road each blast will need to be designed on a case by case basis. Calculations show that a maximum MIC of 50 kg will be required if blasting occurs at the nearest point of the MSSS to the stone arrangement.

The opportunity exists to monitor initial blasting activities in order to progressively update the blast emissions site laws to optimise future blast designs based on actual site conditions and blast parameters.

By adopting this approach it is anticipated that the blast emissions criteria can be met without imposing any significant constraints on blast designs throughout the life of the Project.

Blast emission monitoring and management recommendations are provided in Section 6.


Report Number 630.10123.00820%R2 Revision 0

10 March 2014 Page 4


1 INTRODUCTION 6

1.1 Director General’s Requirements 6

2 PROJECT OVERVIEW 7

2.1 Project Location 7

2.2 Project Description 10

2.3 Construction Hours of Operation 13

3 SENSITIVE RECEPTORS 14

4 BLAST EMISSIONS CRITERIA 16

4.1 ANZECC Guidelines 16

4.2 Criteria relevant to Transmission Lines 16

5 CONCEPTUAL BLAST DESIGN 17

5.1 Assessment Criteria Summary 17

5.2 Blast Emissions Predictions 17

5.3 Construction Blast Designs 18

5.4 Blast Design Best Practices 20

5.4.1 Control Measures for Vibration 20

5.4.2 Control Measures for Airblast 20

6 BLAST EMISSION MONITORING AND MANAGEMENT 21

6.1 Blast Emission Monitoring 21

6.2 Blast Management 22

7 CONCLUSION 23

TABLES

Table 1 Nearest Sensitive Receptors to MSSS 14

Table 2 Blast Emissions Criteria 17

Table 3 Allowable MIC Calculations 19

Table 4 Blast Monitor Specifications 21

Table 5 Meteorological Measurement Parameters 21





FIGURES

Figure 1 Regional Location of Project Application Area 8

Figure 2 Local Setting of Proposed Project 9

Figure 3 Conceptual Layout of Mandalong South Surface Site 12

Figure 4 Nearest Sensitive Private Residential Receptors 15

APPENDICES

Appendix A Predicted Ground Vibration vs Distance Appendix B Predicted Airblast vs Distance





1 INTRODUCTION

SLR Consulting Australia Pty Ltd (SLR) has been commissioned by Centennial Mandalong Pty Ltd (Centennial) to undertake an assessment of potential blasting during the construction of surface infrastructure for the Mandalong Southern Extension Project (the Project).

The Project involves the extension of Mandalong Mine’s existing underground mining operations toward the south into the area covered by Exploration Licence 6317 (EL6317), along with the utilisation of existing and proposed infrastructure integral to the mining operation in terms of coal delivery, handling and transport.

The aim of this assessment was to assess the potential ground vibration and airblast impacts from blasting associated with Project%related construction activities on surrounding sensitive receptors.

The Australian and New Zealand Environmental and Conservation Council (ANZECC) guidelines have been used as the basis of this assessment.

The scope for this Blasting Assessment has been designed to address the Director General’s Requirements (DGR’s) with regard to the assessment of construction impacts. A summary of the DGR’s is provided in Section 1.1.

1.1 Director General’s Requirements

The Director%General of the NSW Department of Planning and Infrastructure (DP&I) issued Environmental Assessment Requirements for the Project on 20 March 2012. These DGRs do not specifically refer to requirements for an assessment of blasting. However, the list of technical guidelines and policies included in Attachment 1 of the DGRs includes the ANZECC guideline Technical basis for guidelines to minimise annoyance due to blasting overpressure and ground vibration (1990).

This assessment has been undertaken in accordance with the relevant policies and guidelines.





2 PROJECT OVERVIEW

2.1 Project Location

Mandalong Mine is an existing underground coal mine operation located in the Lake Macquarie Local Government Area (LGA) approximately 130 kilometres (km) north of Sydney near Morisset within the Newcastle Coalfield of NSW. It is part of the northern operations of Centennial Coal, which consists of Newstan, Awaba, Myuna and Mannering Collieries.

The existing Mandalong Mine Access Site (MMAS), which encompasses underground workings and associated surface infrastructure, is located near Morisset approximately 35 km south%west of Newcastle. The proposed Mandalong South Surface Site (MSSS) is a proposed new surface facilities site to be located within the Southern Extension Area of the Project approximately 6.5 km south%west of the existing MMAS.

The regional location of the Project Application Area is shown on Figure 1, while the local setting of the existing MMAS and the proposed MSSS is shown in Figure 2.





Figure 1 Regional Location of Project Application Area





Figure 2 Local Setting of Proposed Project





2.2 Project Description

Mandalong Mine is an underground coal mine currently operating under the provisions of Development Consent DA 97/800.

The Project proposes to extend Mandalong Mine’s existing underground mining operations into the area covered by EL 6317 in order to access, develop and extract the additional coal reserves identified within the West Wallarah Seam and Wallarah%Great Northern Seam at a rate of up to 6 million tonnes per annum (Mtpa) of run%of%mine (ROM) coal. Among other things, the Project will utilise existing and proposed new surface infrastructure integral to the mining operation in terms of coal delivery, handling and transport.

The primary components of the Mandalong Southern Extension Project include:

• Continue the Mandalong Mine underground mining operations into the area covered by EL 6317 using a combination of continuous miner and longwall mining methods.

• Extract up to 6 Mtpa of ROM coal from the West Wallarah and Wallarah%Great Northern Seams within the current mining lease areas and the area covered by EL 6317.

• Deliver ROM coal from the underground workings to the Cooranbong Entry Site at a rate of up to 6 Mtpa and to the Delta Entry Site at a rate of up to 6 Mtpa.

• Continue to utilise the existing surface infrastructure of the Mandalong Mine Access Site and Delta Entry Site.

• Install and operate additional surface infrastructure for mine ventilation, storage and underground delivery of stone dust, concrete and ballast, hydrocarbon storage, electrical reticulation, water reticulation, water management, floxal unit, communications and other ancillary services and activities.

• Increase manning to 420 full%time employees and up to 50 contractors during longwall relocations.

• Undertake on%going exploration drilling activities within the bounds of Centennial Mandalong’s mining leases and exploration licences.

• Increase the life of mine to 25 years from the granting of a mining lease(s) over EL 6317.

• Continue to operate 24 hours per day, seven days per week.

The Mandalong Southern Extension Project will utilise the entire existing surface infrastructure and facilities at the MMAS, along with the coal delivery system at the Delta Entry Site and the coal delivery system and mine ventilation shaft at Cooranbong Entry Site.

As currently approved for the Mandalong Mine, coal extracted from the Southern Extension Area will be transported from the underground workings via drift conveyors to either the Delta Entry Site or the Cooranbong Entry Site. Once the coal reaches the surface at the Delta Entry Site it is handled by surface infrastructure owned and operated by Delta Electricity. On this basis, the coal delivered to the Delta Entry Site will be handled in accordance with the operations managed by Delta Electricity, which do not form part of the Mandalong Southern Extension Project. Similarly, once the coal reaches the surface at the Cooranbong Entry Site it will become part of Centennial’s Northern Coal Logistics Project, which is the subject of a separate development application. On this basis, the coal delivered to the Cooranbong Entry Site will be handled in accordance with the operations managed by the Northern Coal Logistics business unit, which do not form part of the Mandalong Southern Extension Project.





In addition, the Project proposes to install and operate the MSSS as a new surface facilities site within the Southern Extension Area. The new surface facilities will include infrastructure for mine ventilation, storage and underground delivery of stone dust, concrete and ballast, hydrocarbon storage, floxal unit, electrical reticulation, water reticulation, water management, communications and other ancillary services and activities. The conceptual layout of the proposed new MSSS is shown in Figure 3.

It is noted that construction of the proposed MSSS is considered to be a major component of the potential noise impacts.

There may be a requirement for construction blasting to occur where rock is encountered along some sections of the access road to, and at the site of, the proposed MSSS.





Figure 3 Conceptual Layout of Mandalong South Surface Site





2.3 Construction Hours of Operation

The proposed hours during the construction phase of the Project are typically 7.00 am to 6.00 pm Monday to Friday and 8.00 am to 1.00 pm Saturdays with no work on Sundays or public holidays. The exception to this will be sinking of the new mine ventilation shaft at the MSSS which will be required to occur 24 hours per day, seven days a week.

It is anticipated that construction of the proposed new MSSS will take approximately 2.5 years in total to complete. This includes construction of the Mandalong Road intersection and site access road, ventilation shafts and additional site infrastructure and servicing, along with allowance for wet weather and public holidays.

The construction activities will also involve the erection of temporary buildings and facilities, including light and heavy vehicle access roads and parking areas, equipment storage compounds, diesel generators, diesel compressors, security facilities and services.

It is envisaged that blasting (if required) will only take place during hours of 9.00 am to 5.00 pm Monday to Friday. Blasting is not proposed to take place on weekends or public holidays.





3 SENSITIVE RECEPTORS

A number of residences are located in the area surrounding the MSSS. A list of the nearest sensitive receptors potentially affected by construction blasting, in the vicinity of the MSSS, is presented in Table 1 and shown in Figure 4.

Table 1 Nearest Sensitive Receptors to MSSS

Receptor ID

UTM Zone 56 Elevation (m, AHD) Easting (mE) Northing (mN)

R11 353,449 6,331,020 52

R12 353,006 6,331,635 40

R13 352,732 6,331,781 33

R14 352,513 6,331,701 29

R15 352,327 6,331,484 30

R16 351,703 6,330,361 39

R17 351,461 6,330,079 59

R18 351,554 6,329,722 51

R19 352,086 6,328,535 73

R20 352,607 6,328,751 138

R21 353,870 6,328,675 118

R22 355,151 6,328,201 43

R23 351,274 6,328,436 172

R24 351,825 6,331,330 57

R25 351,710 6,331,225 74

R26 351,570 6,331,105 72

R27 351,395 6,330,720 72

R28 351,190 6,329,000 84

R29 350,750 6,329,085 118

Electricity Transmission Lines

There is also a series of transmission lines in the vicinity of the MSSS; some traverse the access road to the MSSS and another series are located to the south of the MSSS. These are also shown on Figure 4.

Aboriginal Heritage Sites

There are a number of Aboriginal heritage sites in the area surrounding the MSSS. Aboriginal sites potentially sensitive to vibration are rock shelters, grinding grooves and stone arrangements. The locations of the Aboriginal heritage sites are shown in Figure 4.





Figure 4 Nearest Sensitive Private Residential Receptors





4 BLAST EMISSIONS CRITERIA

4.1 ANZECC Guidelines

The NSW EPA advocates the use of the ANZECC guidelines for assessing the potential blast emissions impacts at residential and other vibration and/or airblast sensitive receivers. The ANZECC guidelines are based on human comfort levels and are significantly more stringent than those based on the potential for damage to structures. The ANZECC guidelines are summarised as follows:

• The recommended general criterion for ground vibration is 5 mm/s, Peak Vector Sum (PVS) vibration velocity.

• The PVS level of 5 mm/s may be exceeded on up to 5% of the total number of blasts over a period of 12 months. The level should not exceed 10 mm/s at any time.

• The recommended general criterion for airblast is 115 dB Linear.

• The level of 115 dB Linear may be exceeded on up to 5% of the total number of blasts over a period of 12 months. The level should not exceed 120 dB Linear at any time.

• Blasting should generally only be permitted during the hours of 0900 hrs to 1700 hrs Monday to Saturday. Blasting should not take place on Sundays and public holidays.

• Blasting should generally take place no more than once per day.

These criteria have been applied to the nearest sensitive receptors listed in Table 1.

4.2 Criteria relevant to Transmission Lines

The criterion adopted for the purpose of assessing vibration impacts at electricity transmission lines (100 mm/s) has been based on the findings presented in Effect of Blasting on Infrastructure ACARP Project No C14057 prepared by Terrock Consulting Engineers, dated 20 October 2008.

It is noted that specific criteria applied for any wooden power poles will depend on the condition of the potentially affected power poles and will be determined through consultation with the relevant service provider.

4.3 Aboriginal Heritage Sites

Aboriginal heritage sites in the vicinity of the Project include stones arrangement, grinding grooves and rock shelters. Criteria adopted for these sites are contained in Table 2.

Table 2 Criteria Aboriginal Heritage Sites

Type Vibration Criteria Airblast Criteria

Stone arrangement 3 mm/s 1 N/A

Grinding groove 80 mm/s 2 N/A

Rock shelter 40 mm/s 1 N/A

1 Sourced from Hunter Expressway Alliance – Stage 2 Construction Noise Sub Plan – Seahampton to Kurri Kurri Section dated 2011

2 Moolarben Coal Mines Pty Ltd – Project Approval 05_0117 dated 2007





5 CONCEPTUAL BLAST DESIGN

5.1 Assessment Criteria Summary

The criteria presented in Table 3 have been utilised for the purpose of determining the limiting factors to proposed blasting activities.

Table 3 Blast Emissions Criteria

Location Vibration Criteria Airblast Criteria

Residential receptors 5 mm/s 115 dBL

Transmission Lines 100 mm/s N/A

Stone gatherings 3 mm/s N/A

Grinding grooves 80 mm/s N/A

Rock shelters 40 mm/s N/A

5.2 Blast Emissions Predictions

Site law formulas provide specific relationships between the level of blast emissions and scaled distance. The scaled distance is a fundamental relationship between distance and the maximum instantaneous explosive charge mass (MIC). Assessment of blast emissions often involves the statistical analysis of large amounts of recorded blast events in order to develop a site%specific relationship between scaled distance, MIC and blast emissions.

In the absence of either long term monitoring data, or the opportunity to conduct blasting trials, it is possible to estimate likely ground vibration and airblast levels using charge weight scaling laws. Such site laws incorporate the charge weight per delay and the distance from the blast to the monitoring location. Two site parameters are assumed and influence the peak level and the rate of decay for the levels. The site law formulas have been derived with reference to Orica Mining Services Blasting Guide and Australian Standard AS 2187.2 Explosives—Storage and use Part 2 Use of expolsives % 2006.

Ground Vibration

The charge weight scaling law commonly used for ground vibration is:

�� = K� D√m

Where:

PPV = Peak Particle Velocity (mm/s) m = Maximum Instantaneous Charge mass (kilogram [kg] MIC) D = Distance (m) K = Site constant e = Site exponent

The K value is dependent on the blast interface and the type of rock the blast is being transferred to. For free face blasting of hard or highly structured rock a K value of 500 is typical, for a free face of average rock approximately 1,140 and for near%field heavily confined blasting values of up to 5,000 are not uncommon.

A K value of 1140 for average rock is considered to be appropriate for the assessment of surface vibration levels from blasting for the Project.





A site exponent value of 1.6 is commonly used. For coal mine overburden this ranges from 1.5 – 1.8. The significance of a higher site exponent is that the ground vibration drops off more rapidly and lower vibration results at a greater distance. The use of 1.6 is considered appropriate and conservative.

Airblast

The charge weight scaling law for airblast is:

� = Ka � D∛m

Where:

P = pressure in kilopascals m = Maximum Instantaneous Charge mass (MIC) (kilogram [kg]) D = Distance (m) Ka = site constant a = site exponent

For unconfined blast holes a site constant of 185 and a site exponent of %1.2 are commonly used. For fully confined blast holes a site constant of 3.3 and a site exponent of %1.2 are commonly used. Assuming a fully confined blast hole and converting to decibels the airblast site law is given by:

�� = −24Log � D∛m + 164.2

Where:

dBL = Linear decibels

5.3 Construction Blast Designs

The approach of this assessment was to determine the limiting factors to the blast design for the Project with the aim of achieving the relevant criteria outlined in Section 5.1. Calculations were conducted using the respective blast emissions site law equations (provided in Section 5.2) in order to determine the allowable blast MIC’s that would result in predicted blast emissions at the nearest sensitive receptors of no greater than the relevant criteria.

It should be noted that both the preceding site laws will be subject to review during operations. It is envisaged that there will be modifications to the site laws due to such variables as face orientation, initiation sequencing, stemming depth and location of nearest receptors. Such modifications will be for the purpose of ensuring blast operations do not exceed the required threshold limits. Table 4 contains the results of the allowable MIC calculations. The distances presented in the tables are the closest distance that construction blasting could occur to the identified receptors. The actual vibration/airblast levels for any given blast will depend upon the blast location within the construction area in relation to the nearest sensitive receivers.

A series of graphs showing predicted levels of vibration and airblast verses distance, to aid in blast design, are contained in Appendix A and Appendix B.





Table 4 Allowable MIC Calculations

Impact Assessment Locations

Vibration Criteria (mm/s)

Airblast Criteria (dBL)

Construction Area

Nearest distance to potential blasting (m)

Limiting MIC (kg) based on

Vibration Airblast

R11 5 115 1222 >1000 >1000

R12 5 115 1138 >1000 >1000

R13 5 115 1106 >1000 959

R14 5 115 953 >1000 613

R15 5 115 703 558 246

R16 5 115 587 390 144

R17 5 115 914 943 541

R18 5 115 861 836 451

R19 5 115 1142 >1000 >1000

R20 5 115 759 651 310

R21 5 115 1445 >1000 >1000

R22 5 115 2787 >1000 >1000

R23 5 115 1724 >1000 >1000

R24 5 115 691 539 234

R25 5 115 697 548 239

R26 5 115 752 637 300

R27 5 115 857 830 446

R28 5 115 1480 >1000 >1000

R29 5 115 1841 >1000 >1000

Transmission towers near access road

100 N/A 83 329 N/A

Transmission towers south of site

100 N/A 630 >1000 N/A

Stone arrangement

3 N/A 290 50 N/A

Grinding groove 80 N/A 219 >1000 N/A

Rock shelter 40 N/A 192 560 N/A



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In relation to potential impact at residences, the most restrictive situation, in terms of allowable MIC, is at Location R16 where an MIC of 144 kg would apply due to airblast limitations.

If blasting is required in close proximity to the transmission line towers each blast will need to be designed on a case by case basis. Calculations show that a maximum MIC of 329 kg will be required if blasting occurs at the nearest point of the MSSS to the transmission lines.

In relation to Aboriginal heritage sites if blasting is required in close proximity to the stone arrangement of the western side of the access road each blast will need to be designed on a case by case basis. Calculations show that a maximum MIC of 50 kg will be required if blasting occurs at the nearest point of the MSSS to the stone arrangement.

The opportunity exists to monitor initial blasting activities in order to progressively update the blast emissions site laws to optimise future blast designs based on actual site conditions and blast parameters.

By adopting this approach, it is anticipated that the blast emissions criteria can be met without imposing any significant constraints on blast designs throughout the construction period.

5.4 Blast Design Best Practices

This section provides general blast design techniques that can be applied to minimise potential for blasting related impacts on nearest receptors. These have been sourced primarily from the Department of the Environment document Noise, Vibration and Airblast Control dated 1998.

5.4.1 Control Measures for Vibration

Blast design can be altered to result in reduced levels of ground vibration by:

• Reducing the MIC by using delays, reduced hole diameter and/or deck loading.

• Changing the burden and spacing by altering the drill pattern and/or delay layout or altering the hole inclination.

• Using the minimum practicable sub%drilling which gives satisfactory toe conditions.

Management measures, such as establishing times of blasting to suit local conditions or investigating alternative rock%breaking techniques, may also be applicable.

5.4.2 Control Measures for Airblast

The following measures can be investigated and incorporated to reduce the level of airblast from blasting:

• Reducing the MIC by using delays, reduced hole diameter and/or deck loading.

• Ensure stemming depth and type is adequate.

• Eliminate exposed detonating cord and secondary blasting.

• Restrict blasting events to favourable weather conditions (eg in the absence of source to receptor winds).

• Orient mine faces away from potentially sensitive receptors.

• Use a hole spacing and burden which will ensure that the explosive force is just sufficient to break the ore to the required size.

• Take particular care where the face is already broken and consider deck loading, where appropriate, to avoid broken ground or cavities in the face.



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In addition to reducing the level of airblast emission, many of these control techniques will maximise rock%breaking efficiency, which in turn results in the use of less explosives and an associated cost%saving. Management measures including blasting at a pre%determined time and/or implementation of a pre%warning signal for nearby receptors will help reduce the potential impacts of airblast.

6 BLAST EMISSION MONITORING AND MANAGEMENT

6.1 Blast Emission Monitoring

All blast events should be monitored at a minimum of two locations; a reference location and another location representative of the nearest sensitive receptor. In addition to these monitoring locations monitoring should occur at the closest Aboriginal heritage site to the blasting activity to identify any impacts at these sites.

Blast monitoring instrumentation should be employed to meet the primary specifications presented in Table 5. The instrumentation should be installed, operated and maintained by suitably qualified or trained personnel. The instruments should be externally calibrated at regular intervals throughout the life of the project.

Table 5 Blast Monitor Specifications

Specification Vibration (Seismic) Airblast

Sample rate Minimum 1024 samples per second per channel

Frequency response 2 Hz to 250 Hz (3 dB points)

Resolution 0.016 mm/s 0.1 dB

Range 0.1 mm/s to 254 mm/s 88 dB to 148 dB

Accuracy 3% at 15 Hz 0.2 dB at 30 Hz

Recording mode Full waveform recording and archiving

Vibration velocity geophones should be coupled to the ground via a “star stake” embedded in the consolidated surface approximately 25 m from the sensitive receptor, with the microphone positioned in the free%field.

All blast monitoring should be accompanied by both qualitative description (including cloud cover) and quantitative measurements of prevailing local weather conditions at the time of each blast.

An automatic weather station located in the vicinity of the Project should be used to continuously record the meteorological parameters as shown in Table 6.

Table 6 Meteorological Measurement Parameters

Measured Parameter Unit Sample Interval

Mean wind speed m/s

30 minute Mean wind direction Degrees from North

Aggregate rainfall mm

Mean air temperature oC

Blast design records will be maintained for all blast events. The purpose of the record is to assist in the design and optimisation of future blast events, planning and control of blast emissions and to provide a traceable system of documentation in case of an exceedance or a complaint.

As a minimum, the following blast parameters should be recorded for each blast event:

� Blast identification number



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� Date and time of blast initiation

� Location of blast (East, North, RL)

� Maximum Instantaneous Charge (MIC). [maximum explosive mass to be detonated in any 8ms interval]

� Plan distance from blast location to monitoring station

� Peak Vector Sum(PVS) resultant ground vibration level (mm/s)

� Peak Linear airblast level (dB Linear)

� Burden, spacing and powder factor

� Meteorological conditions (eg wind speed, direction, cloud cover, rainfall)

6.2 Blast Management

Centennial will implement the following blast management measures for all blasts associated with the project:

• Blasting will only occur between 9.00 am to 5.00 pm Monday to Friday. Blasting will not be undertaken on weekends or public holidays

• Blast emissions monitoring (vibration and airblast).

• Appropriate record keeping for all blasts.

Centennial will develop and implement a Construction Management Plan for the Project, which will document the recommendations of this report and the blast management and monitoring practices to be implemented over the construction period. The Plan will include, but may not be limited to, the following:

• Blast emission control measures.

• Blast emission monitoring methodology.

• Process for consultation with neighbouring mines, residents, community, utility providers and Government agencies.

• Response procedures in case of exceedance or complaint.



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7 CONCLUSION

SLR has conducted an assessment of blasting associated with the Project. As no historical blasting data is available for the site, site laws for vibration and airblast were developed from widely accepted generic formulas.

Calculations were conducted in order to estimate the allowable MIC’s for compliance with the respective vibration and airblast criteria at the nearest potentially affected privately owned residential receptors, relevant infrastructure and Aboriginal heritage sites. The results of these calculations are provided in Table 4.

The approach taken for this assessment was to determine the limiting factors to the Project blast design with the aim of achieving the relevant criteria outlined in Section 4 and to provide guidance for future blast designs. Where potential impacts on surrounding sensitive receptors limit the proposed standard blast design Centennial will undertake detailed design of blasts in order to continue to meet the relevant blast emissions criteria.

Blast emission monitoring and management recommendations are provided in Section 6.

Appendix AReport 630.10123

Predicted Ground Vibration vs Distance

0

5

10

15

20

1 250 500 750 1000 1250 1500 1750 2000 2250 2500 2750 3000

Pre

dic

ted

PV

S (

mm

/s)

Distance from Blast (m)

Predicted Vibration vs Distance

MIC=25kg MIC=50kg MIC=100kg MIC=200kg MIC=500kg Criteria (Residential)

Appendix BProject 630.10123

Predicted Airblast Vs Distance

90

115

140

165

190

1 250 500 750 1000 1250 1500 1750 2000 2250 2500 2750 3000

Pre

dic

ted

Air

bla

st

Le

ve

l (d

BL

)

Distance from blast (m)

Predicted Airblast vs Distance

MIC=25kg MIC=50kg MIC=100kg MIC=200kg MIC=500kg Criteria (Residential)

Documents

Mandalong Southern Extension Project Blasting Vibration