Initial Environmental Evaluation Geotechnical Investigations Davis Aerodrome Project (Project 5097) and Davis Station Infrastructure Project ...
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3.0
Initial Environmental Evaluation
Geotechnical Investigations Davis Aerodrome
Project (Project 5097) and Davis Station
Infrastructure Project (Project 5135)
2021-2022 Field Activities
V3.0 – 30 March 2021
INITIAL ENVIRONMENTAL EVAULATION 2021-2022 FIELD SEASONS
Contents
1 Non-Technical Summary ..................................................................................................................... 5
1.1 Introduction................................................................................................................................ 5
1.2 Description of the Proposed Activity .......................................................................................... 5
1.3 Alternatives to the Proposed Activities ....................................................................................... 5
1.4 Impact Assessment ..................................................................................................................... 5
1.5 Mitigation Measures................................................................................................................... 6
1.6 Environmental Monitoring and Management ............................................................................ 7
1.7 Conclusion .................................................................................................................................. 7
2 Introduction and Scope ...................................................................................................................... 8
2.1 Introduction................................................................................................................................ 8
2.2 Davis Aerodrome Project Background ........................................................................................ 8
2.3 Davis Station Infrastructure Project Background ...................................................................... 10
2.4 Statutory Requirements ........................................................................................................... 10
2.5 Purpose and Scope of the Document ....................................................................................... 10
2.6 Previous Assessments and Obligations ..................................................................................... 11
3 Description of the Proposed Activity................................................................................................ 12
3.1 Aims and Objectives ................................................................................................................. 12
3.2 Overview of Proposed Activities .............................................................................................. 12
3.2.1 2020-21 Summer Program ............................................................................................... 12
3.2.2 2021 Winter Program ....................................................................................................... 12
3.2.3 2021-22 Summer Program ............................................................................................... 12
3.3 Location of the Proposed Activity ............................................................................................. 13
3.4 Nominal Sequence of Season Activities .................................................................................... 15
3.5 Site Access and Preparation...................................................................................................... 15
3.6 Geotechnical Investigations ...................................................................................................... 16
3.6.1 Borehole Drilling ............................................................................................................... 16
3.6.2 Borehole Instrumentation Installation and Monitoring ................................................... 23
3.6.3 Downhole Instrumentation Quantum .............................................................................. 25
3.6.4 Test Pit Excavation............................................................................................................ 26
3.6.5 Dynamic Cone Penetrometer testing ................................................................................ 31
3.6.6 Geological Mapping and Geotechnical Visual Observations ............................................. 31
3.6.7 Geophysical Survey........................................................................................................... 32
3.6.8 Near-surface Water Flow Investigations .......................................................................... 33
3.6.9 Lake and Waterbody Depth Monitoring ........................................................................... 33
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3.7 Surveys ..................................................................................................................................... 34
3.7.1 Terrestrial Survey ............................................................................................................. 34
3.7.2 Hydrographic Survey ........................................................................................................ 34
3.8 Equipment, Logistics and Methods of Proposed Activities....................................................... 34
3.8.1 Site Access and Preparation ............................................................................................. 34
3.8.2 Geotechnical Borehole Drilling ......................................................................................... 35
3.8.3 Supply of Drilling Fluid ...................................................................................................... 36
3.8.4 Downhole Instrumentation Monitoring ........................................................................... 36
3.8.5 Temporary Mobile Weather Shelter Provisions ............................................................... 37
3.8.6 Hand-Augered Boreholes. ................................................................................................ 37
3.8.7 Test Pit Excavation............................................................................................................ 38
3.8.8 Dynamic Cone Penetrometer Testing............................................................................... 41
3.8.9 Geological Mapping. ......................................................................................................... 41
3.8.10 Geophysical Survey........................................................................................................... 42
3.8.11 Re-establishment of Existing and/or New Temporary Access Tracks. .............................. 43
3.8.12 Near-surface Water Flow Monitoring............................................................................... 43
3.8.13 Lake and Waterbody Level Monitoring. ........................................................................... 44
3.8.14 Survey ............................................................................................................................... 45
3.8.15 Samples Collection ............................................................................................................ 46
4 Alternatives to the Proposed Activity ............................................................................................... 47
4.1 Do Nothing................................................................................................................................ 47
4.2 Alternate Locations and Timing................................................................................................ 47
4.3 Alternate Methods and Technologies ...................................................................................... 47
5 Description of the Environment........................................................................................................ 48
5.1 Physical Characteristics of the Vestfold Hills ............................................................................. 48
5.1.1 Biota ................................................................................................................................. 50
5.1.2 Birds.................................................................................................................................. 50
5.1.3 Seals ................................................................................................................................. 51
5.1.4 Terrestrial Microbiota ....................................................................................................... 51
5.1.5 Flora ................................................................................................................................. 51
5.1.6 Marine Benthic (Seabed) Biota ......................................................................................... 51
5.1.7 Meteorology and Climate ................................................................................................. 52
5.1.8 Human Presence ............................................................................................................... 52
5.1.9 Scientific Values ................................................................................................................ 53
5.1.10 Wilderness and Aesthetic Values ...................................................................................... 54
5.1.11 Cultural Heritage Values and Historic Importance ............................................................ 54
5.1.12 Location of Main Wildlife Concentrations ......................................................................... 55
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6 Impact Assessment and Mitigation Measures ................................................................................. 56
6.1 Methods and Data Used in Impact Assessment ........................................................................ 56
6.2 Potential Impacts and Mitigation Measures ............................................................................. 56
6.2.1 Impacts on Ice and/or Ice-free Areas ................................................................................ 56
6.2.2 Introduced Materials Associated with Field Activities ...................................................... 59
6.2.3 Works in Proximity to Lakes and Waterbodies ................................................................. 61
6.2.4 Fuel Spills, Waste Disposal and Loss of Equipment........................................................... 62
6.2.5 Vehicle and Equipment Emissions .................................................................................... 63
6.2.6 Native Flora, Fauna and Habitat ........................................................................................ 64
6.2.7 Cultural Heritage Values and Historic Importance ............................................................ 65
6.2.8 Interface with Other Programs or Projects in the Local Area............................................ 65
6.2.9 Cumulative Impacts .......................................................................................................... 66
6.3 Environmental Monitoring and Management .......................................................................... 66
7 Conclusion ........................................................................................................................................ 67
8 Contact details.................................................................................................................................. 67
9 References ........................................................................................................................................ 68
APPENDIX 1 .......................................................................................................................................... 70
APPENDIX 2 .......................................................................................................................................... 76
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1 Non-Technical Summary
1.1 Introduction
The Australian Antarctic Division (AAD) has undertaken this Initial Environmental Evaluation (IEE) of
its proposed 2021-2022 field activities in support of the Davis Aerodrome Project (DAP) (Project
5097) and the Davis Station Infrastructure Project (SIP) (Project 5135), collectively referred to as
“the Project” herein. This IEE covers proposed activities to be undertaken throughout the 2020-21
summer, 2021 winter, and 2021-22 summer seasons.
This IEE has been prepared in accordance with the Antarctic Treaty (Environment Protection) Act
1980 (ATEP Act) and the Antarctic Treaty (Environment Protection) (Environment Impact Assessment)
Regulations 1993 (EIA Regulations).
1.2 Description of the Proposed Activity
The main objectives of the proposed field work associated with the Project, are to continue the
collection of critical geotechnical and environmental data to inform ongoing Project design,
construction, and delivery efforts, essential for the planning phase for the Project, which includes:
· the engineering design of the proposed Aerodrome at the Ridge Site, located approximately 4km
north of Davis Station
· the engineering design of the proposed access track, from Davis Station to the Aerodrome
· the engineering design and logistical planning of assets to facilitate Project construction
· the engineering design of enabling and stabilisation works for the existing Davis Station
infrastructure
· provide supplementary baseline data, to support future infrastructure planning and the
preparation of environmental impact assessments for these activities.
The field program proposed over the 2021-2022 seasons is to nominally comprise a number of
components including.
· fieldwork preparation activities
· geotechnical borehole drilling and test pit excavation investigations,
· the sampling of representative soil, rock, and groundwater
· installation of in-situ monitoring instrumentation, to assess temporal variations in ground
conditions (temperature, movement, and groundwater levels)
· undertake visual geological and geotechnical observations and assessments
· terrestrial and hydrographic surveys; and
· geophysical surveys.
1.3 Alternatives to the Proposed Activities
Investigation of the following alternatives to the proposed activities have been undertaken, and
discussed further in Section 4.0
1. Do nothing.
2. Conduct activities at alternate locations or at different times during the season.
3. Use of alternate methods and technologies.
1.4 Impact Assessment
Key potential environmental impacts associated with the proposed field works, if unmitigated over the
2021-2022 seasons include:
· Emissions from transportation and motorised equipment will have an impact on air quality.
· The potential for minor, localised fuel spills from vehicles and equipment used in the field.
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· The proposed fieldworks will result in short term, visible ground disturbance until the sites are
remediated upon completion of works. Impacts on microbiota and soil processes cannot be
avoided, however these are anticipated to be of a localised scale and deemed short-term.
· The proposed borehole drilling process requires lubrication, with seawater nominated and the
potential requirement for the use of drilling additives where deemed required. Noting the use
of drilling additives, such as calcium chloride and viscosifiers, they are only to be used where
necessary, in minimal volumes required to meet project objectives, aligning with the approach
of the successfully delivered historical geotechnical drilling programmes from previous field
seasons and their use in broader polar environments. The anticipated environmental impacts of
the proposed additives are proposed to be localised in scale and deemed short-term.
o Calcium chloride is to be used to increase the salinity of the drilling fluid which in
turn will reduce the freezing point of the liquid during drilling. This increase in
salinity will prevent the drilling equipment from being frozen within the borehole,
leading to potentially adverse operational impacts. Calcium chloride is nominated as
opposed to sodium or potassium chlorides due to similar performance effects being
realised with a reduced volume of additives applied. The reduced volume of
additives proposed, is suggested to minimise potential environmental impacts.
o Viscosifiers, are proposed to provide a manageable drilling fluid to reduce the
potential for borehole instability and collapse during operations, reducing the
potential for water loss to ground formations during drilling, improve the quality of
sample recovery. Products proposed for use are highly dispersive, versatile blend
of cellulosic and organic polymers which form a high viscosity fluid that exhibits
good hole stabilising characteristics in all types of drilling applications. Where
possible non-toxic and biodegradable options were selected to further reduce the
potential for environmental impacts.
· The combined effect from the noise, vibration and dust from the works will be confined to the
immediate vicinity of the work site and associated service vehicles and therefore are
anticipated to have minor, short-term impacts on wildlife.
1.5 Mitigation Measures
A suite of measures based on past experience and expert advice has been developed to minimise the
environmental impacts associated with this field program. All project personnel deployed to deliver
the proposed fieldwork program will be required to have undertaken an environmental briefing,
based upon this IEE and its related mitigation measures, Environmental Authorisations, Permits,
operational conditions and relevant AAD Standard Operating Procedures (SOP’s)1, notably
Environmental Management and Protection (Volume 1, Chapter 2). All personnel are to be made
aware of their responsibilities as an individual, and collectively and to adhere to the terms of the
governing Environment Authorisations and Permits.
The implementation of the following measures by the Project are proposed to mitigate adverse
impacts on the environment by:
· Consideration as to logistic requirements and the sequencing of location and type of
activities prior to departure, to maximise project efficiency and reduce environmental
impacts by performing the minimum required activities to achieve project goals.
1
https://www.antarctica.gov.au/antarctic-operations/field-operations/field-travel-and-fuel-management/
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· Prior to commencement, worksites are to be reviewed, assessed, and selected to avoid
environmentally sensitive areas, with preference given to using existing disturbed areas and
tracks, where present.
· Upon completion of works, where ground has been disturbed, it is proposed to be reinstated
to visually resemble pre-works conditions, with photographic records of all pre- and post-
works documented.
· All equipment and project materials are to be processed and handled by AAD’s Supply
Services Group who are to be responsible for ensuring compliance with the Australian
Government’s regulations on the export and import of cargo, including scientific samples, to
and from the Antarctic and sub-Antarctic, to prevent the introduction of non-native species
to the Antarctic environment.
· Drilling induced waste is to be managed in accordance with AAD’s Station and Field Waste
Management Guide.
o Solid human waste bagged and kept frozen and liquid waste stored on site in grey
water drums for disposal on station
o All non-human solid waste must be returned from the field to station for sorting and
eventual recycling or disposal to landfill. The drill cuttings collected as part of the
works, where not returned to the borehole upon completion of drilling, are to be
disposed of in the form of Landfill waste, with import permits to be obtained from
DAWE for materials to be treated as landfill material for disposal in Tasmania.
· Waste materials are to be assessed for reuse potential prior to disposal.
· Only appropriately qualified, trained and site inducted personnel are to prepare, inspect,
maintain, and operate fieldwork equipment and machinery.
· The works will be undertaken in accordance with AAD procedures and policies, including
“Work Health and Safety”, “Environmental Protection and Management”, “Station
Operations” (Volume 1, Chapters 1, 2 and 4), “Aviation Standard Operating Procedures”
(Volume 5). Where required, and any supplementary project specific procedure and
requirements will be applied.
· All works are to be undertaken in accordance with Environmental Authorisations, Permits
and Conditions, with an environmental audit framework developed to assist on-site station
leadership undertake inspections as required.
1.6 Environmental Monitoring and Management
Compliance with the AAD’s Environmental Policy and the mitigation measures detailed in this IEE are
the responsibility of all personnel undertaking the proposed activity. The Project’s Field Team Leader
and the Proponent of the activity will actively manage and monitor to ensure adherence to the
relevant policies, procedure, permits and authorisations, including environmental permits and
authorisations.
1.7 Conclusion
This IEE concludes that, provided the recommended mitigations are implemented, the proposed
2021-2022 field activities are likely to have no more than a minor or transitory impact on the
Antarctic environment.
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2 Introduction and Scope
2.1 Introduction
The Australian Antarctic Division (AAD) has undertaken this Initial Environmental Evaluation (IEE) of
its proposed field activities in support of the Davis Aerodrome Project (DAP) and the Davis Station
Infrastructure Project (SIP), collectively referred to as “the Project” herein. This IEE covers
activities being undertaken throughout the 2020-21 summer, 2021 winter, and 2021-22 summer
seasons.
This IEE has been prepared in accordance with the Antarctic Treaty (Environment Protection) Act
1980 (ATEP Act) and the Antarctic Treaty (Environment Protection) (Environment Impact Assessment)
Regulations 1993 (EIA Regulations).
2.2 Davis Aerodrome Project Background
Investigation of year-round aviation access to Antarctica is a key initiative under the Australian
Government Australian Antarctic Strategy and 20 Year Action Plan (2016) to support Australia’s
ongoing Antarctic leadership.
The Strategy and Action Plan 2commits to scoping options for expanded aviation capabilities to
establish a year-round aviation capability between Hobart and Antarctica in accordance with
domestic and Antarctic Treaty system environmental approval requirements. The AAD has
established the Davis Aerodrome Project to undertake this work.
The AAD has previously undertaken a range of geotechnical and environmental investigations
to assist feasibility, site assessment and preferred location of year-round aviation infrastructure
development. The key activities undertaken in previous field seasons, are summarised as
follows:
· Field Season 2012-13; During the 2012-13 field season long term ground condition
monitoring instruments were installed within boreholes at Adams Flat (approximately 4 km
northeast of Davis Station) under the Davis Aerodrome Project. Site investigations were
undertaken including surface geology mapping; shallow test pit excavation and soil
sampling; shallow seismic survey; ecological soil survey and GIS survey. Soil samples for
terrestrial ecology studies were collected from four sites in this field season – Adams Flat,
Heidemann Valley, Old Wallow and Rookery Lake.
· Field Season 2016-17; The fieldwork undertaken in the 2016-17 season focussed on
providing geotechnical and environmental data to assist in site selection decisions for
potential year-round aviation access infrastructure near Davis Station under AAD Year-Round
Aviation Project 5097. The data acquired provided essential for engineering design,
development of project delivery cost estimates, and core inputs to environmental impact
assessments, developed to inform decisions on the feasibility of developing a year-round
aviation access capability between Hobart and Antarctica.
This field season focussed on Heidemann Valley near Davis Station, with a geotechnical and
hydrogeological drilling, sampling, mapping, geophysics, and surveying program. It also
investigated an alternative potential site through surface sampling and mapping at the hard
2
Further details on the Australian Antarctic Strategy and 20 Year Action Plan, including commitments to a number of other
projects that will enhance Australia’s support for scientific research, are available at: http://www.antarctica.gov.au/about-
us/antarctic-strategy-and-action-plan
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rock Ridge Area north of the valley sites. Baseline environmental data was also collected
from numerous lakes and Heidemann Bay Beach.
· Field Season 2017-18; The fieldwork undertaken in the 2017-18 season continued the
collection of geotechnical and environmental data to assist in decisions on site selection for
potential year-round aviation access infrastructure near Davis Station, and to inform
potential future environmental impact assessments.
Given the information obtained from the 2016-17 Field Season, the main focus area for
geotechnical testing was relocated from Heidemann Valley to the Ridge Area. Geotechnical
testing was undertaken with person-portable borehole drilling equipment, involving
excavation of test pits dug on the Ridge Area in areas where sediment covers bedrock,
aerial surveys were undertaken via helicopter, native wildlife observations were undertaken
with additional soil samples were collected for terrestrial and marine ecology studies.
· Field Season 2018-19; Work undertaken over the 2018-19 field season under the year-round
aviation access project focussed on further refinement of the understanding of the geology
and topography of the Ridge Area; a rocky topographically undulating landscape located
about 5 km northeast of Davis Station. Geological, geomorphological, and geotechnical
mapping, borehole drilling and excavation within sediments, and ground stability
assessments further characterised key areas of the Ridge Site to assist informing engineering
design and project delivery cost estimates. Environmental surveys at the Ridge Area, and
wider Vestfold Hills, were also conducted and successful in surveying seabirds and seals and
collecting samples to inform on terrestrial and benthic conditions in the context of potential
environmental impact assessments.
Two field huts were constructed over the 2018-2019 season at the Ridge Site, adjacent to
Camp Lake and still remain, to provide emergency shelter and refuge for expeditioners.
These huts have proven a successful refuge for teams working on the Ridge, however these
are not proposed for use as core project assets for the 2021-2022 field seasons. Further, the
proposed runway centreline was surveyed and marked, with remote piloted aircraft (RPA)
drone imagery capturing the alignment, wider Ridge Site & Adams Flat areas.
· Field Season 2019-20; The fieldwork undertaken in the 2019-20 season continued the
collection of geotechnical and environmental data from the 2018-2019 season, to further
assist in decisions on site selection and inform engineering design considerations for the
Davis Aerodrome Project, and supplement inputs to environmental impact assessments
associated with government approvals.
Noting the information obtained from previous phases of investigative works, the primary
scope included visual assessment and mechanical excavation of test pits in Davis Link,
Adams Flat and the Ridge Site to collect representative soil and rock samples further
informing the understanding of the site conditions. Excavations of test pits were focussed to
understand the sediment thickness and composition where it overlies the bedrock or
permafrost.
In preparation for future site investigations and geotechnical drilling in 2021-2022,
temporary access tracks to approximately 5.5m width have been formed, by clearance of
material causing obstructions to vehicles, .
Based on the previous field assessments, a suitable site for a runway and associated
infrastructure at the Ridge Site in the Vestfold Hills region of East Antarctica was nominated.
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With the Project in the process of developing delivery and procurement options, subject to
government environmental approvals.
2.3 Davis Station Infrastructure Project Background
Geotechnical and environmental investigations are required to inform and support the work of the
Australian Antarctic Division’s (AAD) Antarctic Assets & Infrastructure Branch (AIB). This work is to
support a comprehensive assessment of the current Davis Station Infrastructure and surrounding
station operations area (part of Strategic Infrastructure Project [SIP]) in support of the 20 Year
Action Plan, to inform the future state of Davis Station.
In addition to the above, a suite of stabilisation and enabling works is to be considered at Davis
Station to maintain capability and address existing and planned operations over the coming 2-5
years. The proposed activities presented within this IEE, will assist the planning and development of
stabilisations works only, with a separate environmental application submitted prior to the
commencement of any construction activities.
Past activities in support of infrastructure planning and development include:
· Field Season 2002-2003; The engineering division of the Australian Antarctic Division
undertook a geotechnical investigation of an area at the head of Heidemann Bay, with the
intention to comment on its engineering suitability for a VHF Radar Installation. The site is
located with the flats of the Heidemann Valley, with the surface soils comprising of
fluvioglacial deposits. The surface deposits are generally loose silty sands with surface
boulders. The onsite geotechnical engineer carried out an investigation comprising the
drilling of geotechnical boreholes, dynamic cone penetrometer tests and small-scale test-pit
excavations, reflective of this proposed for the 2021-2022 season. A suite of laboratory
testing was also undertaken on selected samples from the site.
· Field Season 2018-19; Geotechnical site investigations for an engineering improvement to
the existing Davis Station wharf / boat ramp and a new container storage / handling area
was undertaken. The investigation included geotechnical mapping, in situ testing and five
test pit excavations, with representative samples processed and returned to Australia for
testing.
· Field Season 2019-20; Geotechnical site investigations undertaken in 2019-2020 included
manual and mechanical test pit excavations and dynamic cone penetrometer testing to
support the development of engineering concepts for Davis Station stabilisation
requirements. This site investigation focussed on the area to the north of the
Meteorological Building and included investigations into alternative helicopter operation
facilities in Heidemann Valley.
2.4 Statutory Requirements
To ensure the protection of the Antarctic environment, the Antarctic Treaty nations adopted the
Protocol on Environmental Protection to the Antarctic Treaty which came into force in 1998.
Australia enforces the provisions of the Environmental Protocol through the Antarctic Treaty
(Environment Protection) Act 1980 (ATEP Act) and Environmental Impact Assessment Regulations.
The Antarctic Marine Living Resources Conservation Act 1981 (AMLRC Act)implements the
Convention of the Conservation of Antarctic Marine Living Resources.
2.5 Purpose and Scope of the Document
The purpose of this IEE is to provide details of the proposed January 2021 to June 2022 field activities
to support Project engineering design development, present their potential environmental impacts
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and document measures to minimise or avoid such impacts. This document contains the following
sections:
· Section 3 describes the proposed activities
· Section 4 describes the local environment
· Section 5 describes the alternates considered
· Section 6 describes the environmental impacts and the measures proposed to minimise or
avoid them
· Section 7 provides the conclusions of the IEE.
A non-technical summary has been included at the beginning of the document to provide an
overview of the IEE.
2.6 Previous Assessments and Obligations
This IEE builds on Project work completed under previous IEE approvals. A number of sensors,
instruments and equipment has been installed by the Project under previous environmental
approvals. The items which remain insitu are documented in Table 1, with locations to be available
upon request. It is proposed that this IEE reflect these legacy installations and carry these forward
as remediation liabilities with appropriate remediation to be developed as part of ongoing short,
medium- and long-term project remediation strategies, as required.
Quantity Installation Location
Approx. Access tracks to enable vehicle access to drill sites. Ridge Site, Adams Flat,
13km. Davis Link.
12x Lake markers – locations & map available at request. Ridge Site, Adams Flat,
Davis Station
68x 900mm traffic cones. Ridge Site
Placed at 50m intervals along the proposed runway centreline
(double cones placed at 500m intervals). 2x additional cones placed
at relative construction height on Camp Knoll.
148x Stainless steel ‘sediment movement’ rods located across the Ridge Ridge Site
Site with aerial markers and associated ground control points.
2x Melons (huts) fixed close to Camp Lake at WGS84 44S 380765mE Ridge Site
2393678mN
4x 900mm traffic cones. Davis Link
Marking end of access track (to be constructed over 2020 winter).
Offset from high voltage cable.
4x Star pickets with permits attached. Ridge Site, Adams Flat.
4x McLennan Project (P4393 – 2019/19, 2019/20) –Human Impact Adams Flat, Lake Dingle,
monitoring sites Heidemann Valley vicinity.
Table 1: DAP Previously Authorised Activities with Remediation Obligations (as at end 2020 winter)
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3 Description of the Proposed Activity
3.1 Aims and Objectives
The primary Project objective for the 2020-21 summer, 2021 winter, and 2021-22 summer field seasons
are to continue the collection of targeted geotechnical information through the drilling of boreholes,
sampling of representative soil, rock and groundwater samples, excavation of manual and mechanical
test pits, geophysical surveys and topographic / hydrographic surveys to inform the ongoing
engineering design, inform constructability assessments, supplement environmental impact
assessments and assist the procurement of the project delivery partners.
3.2 Overview of Proposed Activities
3.2.1 2020-21 Summer Program
A team of two DAP project personnel have remained at Davis over the 2020 winter and 2020/2021
summer, comprising a plant operator and project scientist, undertaking ongoing maintenance and
operations activities approved under existing permits and approvals.
In preparation for the proposed 2021 winter program, activities will include preparation of access
tracks, clearance of loose surficial material from proposed drill sites, and clearance of materials to
facilitate a temporary plant and materials laydown area on the Ridge site. This will be undertaken by
the same approach as previously, with large rocks relocated to enable access for vehicles and plant,
adequate space for the drilling rig, and a location for the storage and staging of drilling consumables,
plant, and shelters on the Ridge.
3.2.2 2021 Winter Program
The 2021 wintering project field team will replace the 2020 wintering team and comprise specialist
geotechnical drilling subcontractor (2 persons), geotechnical engineer and plant operator deployed
on Voyage 2, departing Hobart for Davis mid-February, and arriving late-February 2021. Project
personnel requirements for the 2021/22 Summer season are to be determined and will be determined
in collaboration with the project team and interfacing AAD Branches.
Upon arrival, resupply operations, station and project inductions and survival training activities are
proposed to occur over the initial 10-14 days following arrival, with fieldwork commencing upon
completion, pending environmental approval.
Fieldwork will continue until a few weeks prior to departure, estimated November 2021, with return
to Hobart anticipated December 2021.
The 2021 Winter field program is proposed to comprise a number of components subject to
weather and operational constraints, and nominally includes.
· Geotechnical borehole drilling and test pit excavation investigations.
· Installation of in-situ monitoring instrumentation, and
· Visual geological and geotechnical observations
3.2.3 2021-22 Summer Program
Depending on the outcomes and productivity achieved over the 2021 Winter season, the 2021/22
summer scope will be defined by mid-2021. Based on anticipated outcomes, subject to weather and
operational constraints, the following scope is nominally proposed:
· Supplementary geotechnical borehole drilling and test pit excavation investigations.
· Ongoing monitoring of in-situ geotechnical and hydrogeological instrumentation,
· Visual geological and geotechnical observations,
· Terrestrial and hydrographical survey, and
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· Geophysical surveys
3.3 Location of the Proposed Activity
Figure 1 defines the nominal areas of the proposed 2021-2022 Field Season activities, which will be
undertaken within proximity of Marchants Landing, Davis Station Limits, Davis Link, Adams Flat,
Heidemann Valley and the Ridge Site. Proposed geotechnical borehole and excavation locations are
to be determined on site following receipt of environmental permit conditions, site terrain,
weather, and access constraints.
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Figure 1 – Project Location Plan
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3.4 Nominal Sequence of Season Activities
Based on the current communicated AAD Operational Programs and vessel departure dates, the
following sequence of works is proposed in order to meet the project requirements.
Activity* Nominal Duration of Activity
Ongoing site preparation works (under existing environmental January 2021
approvals)
Deployment of plant, equipment, and personnel Mid February 2021
Station resupply activities Late February – Early March
2021
Commissioning and testing of geotechnical drilling equipment March – Early April 2021
Station safety training and site familiarisation Late March 2021
Drilling of select high priority geotechnical boreholes to April– June 2021
facilitate downhole instrumentation installation (Davis Link,
Adams Flat and Ridge Site)
Drilling of medium priority geotechnical boreholes to facilitate June – August 2021
technical site understanding (Ridge Site, Adams Flat)
Drilling of low priority geotechnical boreholes to facilitate September – October 2021
technical site understanding (Davis Link, Davis Station,
Marchants Landing and Heidemann Valley
Excavation of test pits to facilitate understanding of site October 2021
conditions (Davis Station, Davis Link and Heidemann Valley)
Monitoring of borehole instrumentation throughout the Monthly following installation
season
Sample Processing and transport preparation October 2021
Equipment “Break-down” for transport Late October 2021
Return to Australia (RTA) of winter personnel, equipment, and Early November 2021 - TBC
samples
Station resupply activities Early November 2021 - TBC
Delivery of remaining project activities November 2021 – February
2022 - TBC
RTA of summer personnel, equipment, and samples March 2022 - TBC
* Note – priorities of geotechnical drilling locations may change depending on site, engineering, program constraints and or
opportunities.
3.5 Site Access and Preparation
Prior to the proposed Project geotechnical site investigation activities commencing, a number of
preparatory activities are deemed necessary, to facilitate the efficient delivery of the works, and
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proactively manage program and environmental risk in advance of the geotechnical drilling and
excavation program. Site access and preparation tasks may include:
· Formation of temporary vehicle and plant access tracks of nominal 5.5m width, to sites of
geotechnical interest within the project extents, requiring the clearance of surficial sediments and
rocks causing vehicle obstructions to create temporary access tracks for geotechnical drilling
equipment and support vehicles. Extents of additional access track formation are to be
determined, however for the purposes of planning a nominal additional of 7500m is proposed,
noting extents are to be minimised where possible to reduce environmental disturbance and
impact. Visual reinstatement of ground disturbance are proposed to be undertaken upon
completion of the program, in addition to documentation of photographic records of pre- and post-
work conditions.
· Formation of temporary working areas to provide a safe and functional environment for field staff
at each borehole location up to ~150m2 within Marchants Landing, Davis Station limits, Davis Link,
Adams Flat, Ridge Site and Heidemann Valley. To safely undertake the proposed drilling works,
temporary relocation of surficial material within the drilling working platform may be required.
Visual reinstatement of ground disturbance are proposed to be undertaken upon completion of the
program, in addition to documentation of photographic records of pre- and post-work conditions.
· Placement of asset and utility protection culverts to facilitate vehicle and plant access. It is
anticipated 15 asset protection culverts are required to be placed over existing on ground assets to
prevent damage associated with vehicle access within Davis Station limits. Locally sourced crushed
rock, from existing station stockpiles, will be used to backfill and provide support the works. Assets
requiring protection may include power, communications, water, and infrasound cables. Visual
remediation of ground disturbance are proposed to be undertaken upon completion of the
program, in addition to documentation of photographic records of pre- and post-work conditions.
· Clearance of surficial materials and obstructions, to facilitate up to 5 temporary works storage areas
within the project areas, to reduce excessive haulage distances and minimise environmental
impacts. These areas of nominally 100m2 each, are proposed to facilitate project works within
Davis Link, Adams Flat and the Ridge Site. Visual reinstatement of ground disturbance are proposed
to be undertaken upon completion of the program, in addition to documentation of photographic
records of pre- and post-work conditions.
It is proposed these activities will commence during the 2020-21 summer season and continue into the
2021-2022 future field season(s) as required.
3.6 Geotechnical Investigations
3.6.1 Borehole Drilling
3.6.1.1 Overview
To provide the integral geotechnical information to inform the ongoing planning, engineering design
and delivery of the Project, a targeted geotechnical drilling program has been developed based on the
project concepts, anticipated ground conditions and areas of greater geotechnical risk and uncertainty.
The approach to define geotechnical scope has been developed on the principles of maximising the
quality and quantity of geotechnical information to inform stages of the project life cycle, while
minimising potential environmental impacts and disturbance. To deliver the geotechnical drilling
program for the Project, a specialist geotechnical drilling sub-contractor with proven experience in
remote, polar environments has been engaged in accordance with AAD procurement guidelines.
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During the 2017-18 summer season, the Project successfully drilled ten cored geotechnical boreholes
to a depth of approximately 10 m below existing surface, with a core diameter of up to 70 mm. The
intent of this investigation was to determine continuity of the rock to depth and to collect
geotechnical information and samples.
Utilising the information acquired from the 2018/19 season, the project has procured specialist
drilling equipment and personnel with proven experience in similar ground conditions and working
environments. The Project proposes to deliver the scope of work, by utilising a rotary drilling rig,
mounted within a purpose built skid trailer to drill boreholes to ensure the recovery of suitable soil
and rock core samples, up to 100mm diameter to depths up to 60m below existing surface. The
purpose of such investigations are to further develop the project understanding of the site conditions
and assist in the management of technical and construction risk by:
· assessing the depth and composition of the unfrozen soils from ground surface to
permafrost
· assessing the thickness and composition of the soils within permafrost layer(s), if
encountered
· measuring the depth to basement rock
· assessing the lithology, structure, and composition of the existing bedrock.
The co-ordination and sequencing of the geotechnical drilling program has been developed to
prioritise locations of interest, and to utilise the changing weather conditions to the field teams’
advantage to minimise environmental impacts and to acquire the relevant samples and information.
The intention will be to focus the drilling of higher priority locations earlier in the program, notably
in the vicinity of Adams Flat, Camp Lake Valley and East Valley. Focussing efforts on locations
where downhole monitoring instrumentation is proposed, will allow the project team to acquire
seasonal information available to share with the project delivery team as required. In addition,
where there is the potential for activities to induce ground disturbance due to soft and unfrozen
ground conditions in Summer, works are to be sequenced to undertake drilling activities in the
cooler months, where there is greater potential for surfaces to be frozen and less susceptible to
disturbance.
The program is to be delivered by specialist a geotechnical drilling contractor with a proven history
of delivering complex and challenging geotechnical drilling programs in remote, polar conditions.
The skills and knowledge they will bring to the project are anticipated to maximise the quality of the
drilling works, optimise the speed of project delivery, and ensure adverse environmental impacts
are minimised.
The Zinex A5 drilling rig proposed to be mobilised for the program has successfully been deployed
on drilling programs in the northern hemisphere Arctic since 2012 and have proven reliability under
adverse environmental conditions. With the flexibility of the drilling rig to be mounted on a skid or
wheeled trailer, depending on existing surface conditions, the “set-up” and “take-down” time
between drill sites will be reduced minimise environmental disturbance. The drilling unit is
equipped with outriggers to level the drill and have the option for large all terrain wheels to assist
with mobilization in the rockier areas, or ‘broken down’ into modules and transported by
telehandler or helicopter depending on accessibility constraints. Figure 2. Geotechnical drilling is
proposed to be undertaken by a single drilling rig and crew, with operations limited to a single
location at a time, with works aligned to standard Station operating hours. Additional equipment
will be mobilised to accommodate contingency and redundancy requirements.
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The dimension of the skid mounted drilling trailer is approximately 4m in width by 6m in length,
with the supporting equipment and plant module, containing drilling rig power sources
approximately 2.5m in width and 6m in length. The supporting container is capable of being
located at distance from the drilling trailer in the event site conditions require. The arrangement of
drilling equipment on site will be positioned to maximise staff safety considerations, while
minimising environmental impacts. Site arrangements will be assessed on a site-by-site basis
depending on weather and topographical constraints and environmental sensitivities.
Figure 2 – Example of typical Zinex A5 Drilling Rig and Setup
Continuing from the approach adopted from historical geotechnical drilling programs at Davis, to
facilitate the drilling process seawater is proposed to be used as the primary drilling fluid medium to
lubricate the borehole and ensure core recovery. Seawater would be sourced from Prydz Bay in the
vicinity of Davis Station, Heidemann Bay or West Bay, as required. Multiple locations have been
nominated, refer to Section 3.8.3, with the intention to reduce haulage distances and durations and
optimise project efficiencies as these will collectively reduce environmental impacts associated with
vehicle emissions and ground disturbance. Seawater is proposed to be pumped into intermediate
bulk containers (IBC’s) for storage and transportation by vehicle or helicopter to the required drilling
location.
To facilitate coring at the deeper borehole locations, the potential may arise to require the salinity of
the drilling fluids to be increased, to reduce the potential for the drilling fluids to freeze while below
the surface. Reflective of the drilling methodology successfully deployed and approved in 2013 and
2016, it is proposed that calcium chloride is added to the seawater where required, to prevent the
freezing of drilling equipment into the borehole and facilitate sample retrieval, with the solid drill
cuttings (sediment having fallen out of drilling fluid suspension) removed to reduce the potential for
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plant damage during operations. Where downhole instrumentation is not proposed to be installed at
the borehole location, the rock cuttings are proposed to be returned into the borehole, the
environment in which they originated, upon completion of works. Where this approach is not
possible, drill cuttings are to be treated as Landfill waste in accordance with AAD Waste Management
Procedures. Discharge of excess seawater-based drilling fluids, nominally 1200 litres per borehole
location, where unable to be directly removed from the treaty area, is proposed to be directly
discharged to the marine environment in a manner that takes into account the assimilative capacity
of the receiving marine environment. The discharge location is to be nominated in collaboration with
AAD Science Branch and focused to locations where conditions exist to promote dilution and rapid
dispersal, to minimise adverse impacts on local marine ecosystems or species. Where practicable
additional measures will be employed to reduce residual risks of impacts to the marine environment,
including reducing sedimentation and other contaminant material in the fluid.
It is proposed the drilling water remaining within the borehole is allowed to freeze, to form a natural
backfill material, with the upper section capped at surface with local sediment, drill cuttings and
cementiceous grout to negate the potential for native vertebrate entrapment and facilitate visual
remediation of the site.
Figure 3a and Figure 3b summarise the nominal, high priority borehole location plans based on
anticipated conditions. The final locations are to be assessed prior to works, dependent on
environmental and operational factors.
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Figure 3a – Nominal High Priority Borehole Locations (Davis Station, Davis Link and Adams Flat)
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Figure 3b – Nominal High Priority Borehole Locations (Adams Flat and Ridge Site)
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3.6.1.2 Marchants Landing
To assess the ground conditions at locations of interest to support the potential Davis Station
stabilisation works, the drilling of geotechnical boreholes at up to 10 locations is proposed. Locations
are to be prioritised with locations and depths proposed based on engineering design requirements,
reviewed mid-2020. Based on the anticipated form of engineering structures and ground conditions,
the boreholes are proposed to be drilled to maximum depths of 25m below ground level (mbgl) with
Recovered soil and rock samples to be visually described, photographed, and retained for laboratory
testing upon RTA.
3.6.1.3 Davis Station Limits
The targeted site investigation to assess the ground conditions at locations of the proposed Station
wharf, enabling and stabilisation infrastructure, includes the drilling of geotechnical boreholes at up to
15 locations within Davis Station Limits. The boreholes are to be drilled to a maximum depth of 25m
below ground level (mbgl), with recovered soil and rock samples to be visually described,
photographed, and retained for laboratory testing upon RTA. Locations have been prioritised and
proposed based on the engineering concept design and the anticipated ground conditions, with the
view to maximise the geotechnical understanding of the site and minimise environmental impacts and
project delivery risk.
3.6.1.4 Davis Link
The targeted site investigation includes the drilling of geotechnical boreholes at up to 15 locations
within Davis Link to inform the design of the Aerodrome access track. The boreholes are anticipated to
be drilled to a maximum depth of 15m below ground level (mbgl), with recovered soil and rock samples
to be visually described, photographed, and retained for laboratory testing on station or up on RTA.
Locations have been prioritised and proposed based on the engineering concept design and the
anticipated ground conditions, with the view to maximise the geotechnical understanding of the site
and minimise environmental impacts and project delivery risk.
3.6.1.5 Heidemann Valley
The proposed geotechnical program includes the drilling of boreholes at up to 10 locations within
Heidemann Valley and the surrounding hinterland, to inform the design of temporary construction
compounds and temporary access tracks. The boreholes are anticipated to be drilled to a maximum
depth of up to 20m below ground level (mbgl), with recovered soil and rock samples to be visually
described, photographed, and retained for laboratory testing on station or upon RTA. Locations have
been prioritised and proposed based on the engineering concept design and the anticipated ground
conditions with the intention to maximise the geotechnical understanding of the site and minimise
environmental impacts and project delivery risk.
3.6.1.6 Adams Flat
The targeted site investigation includes the drilling of geotechnical boreholes at up to 20 locations
within Adams Flat to inform the design of the Aerodrome access track and High Intensity Aviation
Lighting (HIAL) structures. The boreholes are anticipated to be drilled to a maximum depth of up to
25m below ground level (mbgl), with recovered soil and rock samples to be visually described,
photographed, and retained for laboratory testing on station or upon RTA. Locations have been
prioritised and proposed based on the engineering concept design and the anticipated ground
conditions with the intention to maximise the geotechnical understanding of the site and minimise
environmental impacts and project delivery risk.
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