201218 esparon, andrew development of a novel method for continuous monitoring of vegetation...

8/2/2019 201218 Esparon, Andrew Development of a Novel Method for Continuous Monitoring of Vegetation Regrowth on a Rehabilitated Minesite Using a Simple LED Spectroradiometer

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Supervising Scientist - working to protect the environment from the impacts of uranium mining

www.environment.gov.au/ssd

Development of a novel method for continuous monitoring of vegetation

regrowth on a rehabilitated minesite using a simple LED spectroradiometer.

Andrew Esparon

Environmental Research Institute of the Supervising Scientist

Spatial Sciences and Data Integration


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2Supervising Scientist Division

Overview

Background of the issues to be addressed.

Description of the importance of these issues

Research activities Laboratory testing to assess spectral characteristics of plants and soils

Development and testing of the LED continuous monitoring device

Deployment devices in the field (On the Trial Landform and on ananalogue site).

Outline of the timing for various stages of research


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Overview of the issues to be addressed.

Approximately 60 countries have embarked on the road to nuclearpower (2010).

These nuclear power reactors consume about 68,000 tonnes ofuranium per year


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The mining methods used in Australia to extracturanium are

Open cut

Underground

In-situ leach

Open cut mining method is the mostenvironmentally visible


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Four active mineral leases within the AlligatorRivers Region (ARR)

Ranger

Jabiluka

Koongarra Nabarlek


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Jabiluka: care &

maintenance


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Jabiluka: care &

maintenance

Nabarlek:

Operational 1979-1989

Decommissioned 1995




Jabiluka: care &

maintenance

Ranger mine:

Discovered 1969,

Operation 1981,

Prod. ~ 5000 t/a,

mining ceases

~2014

Nabarlek:


Decommissioned 1995




Jabiluka: care &

maintenance

Ranger mine:

Discovered 1969,

Operation 1981,

Prod. ~ 5000 t/a,

mining ceases

~2014

Koongarra:

undeveloped

mineral lease

Nabarlek:


Decommissioned 1995




Ranger Uranium Mine is currently the onlyoperational mine.

10.3 km2 cleared of vegetation (Oct 2011)

265 meters maximum pit depth




Currently there are no good examples in thewet-dry tropics of successful reclamation of hardrock mines.

Development of the Trial Landform at Ranger in

2008/2009 covering approximately 200 m x400 m (8 ha).

Waste rock and a waste rock mixed with finermaterial called laterite were used to constructthe Landform.




The re-vegetation process is an importantaspect in the development of the finalrehabilitated landform

Different planting methods of various species of

plants and the implementation of differentplanting methods is being explored

It is important to continuously monitor plantgrowth to determine the vegetation response tochanging environmental conditions throughoutthe year




A traditional method of remote monitoring ofplant status is monitoring of plant indicators suchas the commonly used Normalized DifferenceVegetation index (NDVI)

where NIR and Red are reflectance in nearinfrared and red bands respectively.




It is well known that photodiodes coupled withoptical band-pass filters can be used to measurethe intensity of radiation in the wavelength bandof the band-pass filter

A LED can be used as a spectrally selective filterthat replaces both the photodiode and the filter.




Advantages of a simple LED spectroradiometer Low cost

High stability

Power efficient

Small/light

Allows continuous monitoring of NDVI and othervegetation indices for a variety of plant speciesin the field.

These measurements will allow investigation ofdiurnal and annual variations in vegetationstructure and metabolism variables.




The general public is wary of Uranium miningbecause of the impact on the environment andthe associated radioactivity

In Australia, the experience of rehabilitating

uranium mines is questionable Rum Jungle

Radium Hill

Mary Kathleen

South Alligator group of mines

All still present environmental and radiologicalmanagement problems




Public concern increases when such a facility isto be decommissioned

Clear rehabilitation strategies need to be inplace for public reassurance and legislative

obligations.




The method of re-vegetation of the TLF will formthe model for the rehabilitation of the entireRanger mining area.

The success of this model will also assist in final

closure criteria of legacy first generation uraniummines.



Research activities

The work program of this research proposal willinclude the following activities:

Laboratory testing to assess spectral characteristicsof plants and soils

Development and testing of the LED continuousmonitoring device

Deployment of a number devices in the field. On theTrial Landform and on an analogue site.



Laboratory testing

Laboratory testing to assess spectral characteristics ofplants and soils

Use ASD spectrometer to measure spectra of variousplant species and waste rock material from the TLF todefine the spectral bands of interests that will require

monitoring

Quantify the spectral response measured as afunction of

Moisture content response due to changes in relative

humidity Viewing geometry (distance between the spectrometer and

the sample, field of view, lighting and viewing angle).


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Laboratory testing to assess spectral characteristics ofplants and soils

Laboratory testing


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Development of the LED device

Spectrally characterise LEDs using a tuneablelight source and a picoammeter to measurecurrent

LEDs will be selected with peak emissionwavelengths near the centre of the spectralbands of interest (Red(675nm) and NIR (800nm)for NDVI)


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The next step is to interface the LEDs to a

microcontroller (Texas instruments MSP430series)

Records the signal from the LED when it is exposed light

Performs both analogue and digital operations on a single

chip with minimal peripheral circuitry Three operational amplifiers can be linked together

programmatically on the chip to form a trans-impedancecircuit to amplify the small current generated by the LED

The amplified signal is then converted to a number using the

ADC. The digital architecture performs the task of data logging the

recorded measurements including date and time (SDcard/GPRS modem).

Ultra-low powered (Active Mode: 300 A at 1 MHz, 2.2 V)


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Microcontroller programmed in C/C++



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One of the main parameters being measured isNDVI and this can be measured by selecting twoLEDs that are sensitive to the near infrared andred bands.

Put simply the reflectance is calculated as:


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Initial testing of the performance of the LEDspectroradiometer will be conducted at SSD prior todeploying in the field.

A weatherproof camera will be deployed that willtake a photo every time a reading is taken by theLED monitoring device.

A weather station will also be set up to assist in theassessment of measurements by providing valuableinformation about environmental conditions whenthe measurements are taken


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Deployment in the field

Deployment of a number devices in the field. Trial Landform

Georgetown analogue site

Need to address following issues

Mounting and setup of the devices

Maintenance and repair

Access to analogue site


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Work Plan

Milestone Start Expected completion

Quantify the spectral response of the target measurement as a function ofmoisture content and viewing geometry.

Develop method to calculate the fraction of vegetation green cover and

NDVI using LEDs as sensors.

6th Feb 2012 31st Apr 2012

Spectrally characterise LEDs and construct eight MCU/LED devices. This

includes the construction of the housing, fabrication of all electronic

components, and programming of the MCU.

7th May 2012 31st Aug 2012

Deploy eight monitoring devices outside the SSD office.

Download data from the LED devices outside the SSD office and make an

assessment of data collected and device performance.

19th Sep 2012 30th Nov 2012

Submit journal article detailing the construction of the LED device and

methods of measurement.16th Dec 2012

Deploy monitoring devices on the TLF (regular field trips will be conducted

to download data and check the setup).

1st Feb 2013 31st Aug 2013

Compile and analyze data collected from the LED devices in the field. 16th Feb 2013 14th Sep 2013

Submit project thesis 31st Oct 2013

Submit second journal article describing the results measured in the field. 16th Dec 2013


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Acknowledgements

Project Supervisor

Stefan Maier (Charles Darwin University)

Associate Supervisors

Ping Lu (Energy Resources of Australia Ltd)

Lindsay Hutley (Charles Darwin University)


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Questions?

201218 esparon, andrew development of a novel method for continuous monitoring of vegetation...

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