Leigh Creek Energy constructed and operated an UCG demonstration plant at Leigh Creek, within the old mine site. This demonstration plant involved the establishment of a single gasifier chamber and associated above-ground infrastructure to produce synthesis gas (commonly referred to as syngas) for a short period of time, to test the syngas composition and process performance to enable consideration of potential commerciality.

Gasifier initiation was reported on 10 October 2018. On the 11th April 2019 Leigh Creek Energy commenced decommissioning of the gasifier following the completion of the demonstration period. Ongoing monitoring of pressure, temperature, ground water quality and soil vapour will continue in line with the groundwater and soil vapour monitoring plan.

Assessment and approval of the pre-commercial demonstration plant

The Minister for Energy and Mining on 19 April 2018 approved the Leigh Creek Energy Statement of Environmental Objectives (SEO) in accordance with Part 12 of the Petroleum and Geothermal Energy Act 2000 (PGE Act). The Department for Energy and Mining has developed an assessment summary report to summarise the main findings in relation to the potential issues and environmental risks associated with the Leigh Creek Energy Underground Coal Gasification (UCG) trial proposal and how they will be managed. The source of this information is from that detailed in the submitted Environmental Impact Report (EIR) and from additional information acquired by the Department as the lead regulator of this project. All this information along with public submissions and advice from other co-regulatory agencies and independent geo-mechanics and UCG experts was utilised to inform the approval process for the SEO under the PGE Act.

For a copy of the assessment summary report please see below:

The Department engaged Dr Gary Love to review the physical aspects of the subsurface at the Leigh Creek Energy site that are primary factors in containment of the UCG process, and to provide an expert statement on the suitability of this site for the purpose of UCG. Dr Love is a recognised Australian expert in the field of UCG who amongst other credentials detailed in his expert statement report he has appraised numerous potential sites for UCG both in Australia and internationally. Since 2014, he has acted as a fact witness and subject matter expert to the Queensland Department of Environment and Science (formerly Department of Environment and Heritage Protection) in the investigation and prosecution of Linc Energy, and has given evidence in the committal and trial.

The review also considered relevant operational risk factors described in the EIR, specifically the approach to well design and the definition of the safe operating pressure envelope, and the Linc Energy Limited UCG program in Queensland and the relevance of that experience to the proposed Leigh Creek Energy operation.

In summary, his findings detailed in his expert statement can be found in the report below:

Whilst approval of the SEO was a significant step within the approvals process, this still did not provide rights to Leigh Creek Energy to begin on-ground works. To do this, Leigh Creek Energy were required to proceed to the third and final approval stage to obtain approval to commence on ground activities. This entailed submission to the Department for evaluation and approval of all technical and engineering designs relating to this activity to ensure the design and intended construction and monitoring of all surface facilities, pipelines, underground gasification chamber and wells are in accordance with recognised industry standards and fit for the purpose for achieving the requirements of the final approved SEO and conditions. Further information on Stage 3 approvals are provided within the assessment summary report.

The stage 3 activity notification and approval process was undertaken in 3 phases. Each phase for approval, along with a respective decision or indicative assessment progress and date, are provided in the table below.

It is important to note that, where relevant, subsequent phases of approval were subject to the successful execution of the preceding phase of approved activities.

PCD production suspension and extension

On 5 November 2018, Leigh Creek Energy requested a temporary suspension for up to 4 weeks for its 90 day UCG trial for the purpose of re-igniting the gasifier. In response, on 7 November 2018 the Department for Energy and Mining – Energy Resource Division (DEM-ERD) approved the suspension of the trial conditional to at the expiration of the suspension (a maximum of up to 4 weeks to 5 December 2018), the 3-month UCG trial period will recommence.

Date Posted - Wednesday, 7th November 2018

DEM-ERD’s decision to grant Leigh Creek Energy a temporary suspension for up to 4 weeks for its 90 day UCG trial was informed and supported by independent expert, Dr Clifford Mallet, as outlined in Part 3 of his review of the Leigh Creek ISG pre-commercial demonstration facility.

On 1 February 2019, Leigh Creek Energy requested a 3-month extension of the production period as approved under Section 27(3) of the Petroleum and Geothermal Energy Act 2000. Leigh Creek Energy outlined within the request that the Pre-Commercial Demonstration (PCD) is still in its commissioning (or “ramp up”) stage and has yet to sustain full flow rate gasification and production of syngas as defined in the relevant Environmental Impact Report (EIR).

In response, on 6 February 2019 the Department approved an extension to the original 3-month production period for three months until 7 May 2019.

Date Posted - Thursday, 7th February 2019

PCD decommissioning

On Thursday the 11th April 2019, Leigh Creek Energy commenced the decommissioning process of its gasifier in accord with its approved PCD decommissioning plan.

The ongoing monitoring of pressure, temperature, ground water quality and soil vapour will continue for 3 years post operation as part of the evaluation process to ensure successful decommissioning and containment of chemicals of potential concern within the gasifier has been demonstrated.

The Department will continue publishing the pressure monitoring data to demonstrate containment as it has during the gasification process.

Demonstration plant gasification process monitoring

Leigh Creek Energy was required to undertake considerable monitoring both on-site and in surrounding areas to ensure the underground coal gasification demonstration plant was compliant with approvals and operating safely in relation to people and the environment.

Post operation monitoring of the gasifier pressure, temperature, ground water quality and soil vapour will continue in line with the groundwater and soil vapour monitoring plan for 3 years.

The following facts sheet is intended to provide the public with easily accessible information and highlight key aspects of the monitoring program for the Leigh Creek Energy underground coal gasification process.

Data updated 30 June 2019

The follow monitoring data is presented in accordance with the diagram below, which represents an illustration of the three monitoring zones – green (greater than 100 metre radius), amber (~15-100 metre radius) and red (~0-15 metre radius) around the gasifier – which align with expected monitoring program observations. Further information on the monitoring programs for the Leigh Creek Energy UCG Demonstration Plant Gasification Process is provided in the guide above.

Green zone (area outside of 100 metre buffer zone including the shallow main series overburden):- 
From the date of ignition the sensors in the shallow overburden rock between 96 to 103 metres depth have shown no signifcant change in pressure (blue curve) and temperature (orange curve). No pressure and temperature variance from baseline is expected in this zone.

Amber zone (up to 100 metre buffer zone around the gasifier chamber including the main series overburden):-
From the date of ignition the sensors in the overburden rock between 415 to 493 metres depth have shown a minor decrease in pressure (blue curve) and no change in temperature (orange curve). Some pressure and temperature variance from baseline is expected in this zone given it is within 100 metre from gasifier.

Red zone (area including the gasifier chamber and surrounding main series coal seam):-
From the date of air injection and subsequent ignition, the sensors surrounding the gasifier chamber in the coal seam between 485 to 512 metres depth have shown a decrease in pressure (blue curve) and no change in temperature (orange curve). The decrease in pressure is mainly due to air circulation and depressurising between inlet and outlet wells, creating a pressure sink in the gasifier chamber. No change has been observed in temperature sensors approximately 15 metres from the ignition point in the coal seam. Coal has very low thermal conductivity and it is unlikely that any significant change in temperature will be seen in the sensors in the coal seam.

Furthermore, the gasifier pressure is at approximately 1,600 kPa post-decommissioning, which is below baseline hydrostatic pressure at approximately 5,000 kPa and also below surrounding pressure, indicating there is inward flow towards the gasifier and no loss of containment.

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Air quality monitoring - final summary report

Leigh Creek Energy were required to undertake Air Quality Monitoring prior to, during and post decommissioning of their in-situ gasification (ISG) demonstration plant in line with their approved Air Quality Monitoring Plan (AQMP). The AQMP was developed to demonstrate compliance with the ISG demonstration plant Statement of Environmental Objectives (SEO).

Leigh Creek Energy have developed a summary report of all air quality and odour monitoring undertaken in line with the AQMP. The Department concur with the conclusions of the report, in particular that Leigh Creek Energy have met the requirements of the AQMP and demonstrated compliance with the SEO, in particular the assessment criteria that ‘regular air quality measurements indicate levels are below relevant health-based air quality criteria (as listed in the Environment Protection (Air Quality) Policy) at sensitive receptors (i.e. towns or residences).’ The Department consulted with the Environmental Protection Authority on the content and conclusions of the summary report prior to its acceptance.

The final summary report is provided below.

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Frequently asked questions

The following frequently asked questions aims to provide the public with easily accessible and comprehensive responses to a range of questions asked by the public in relation to underground coal gasification. If you have a relevant questions not answered in the document, please contact us at DEM.Petroleum@sa.gov.au.

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Research projects

As part of informing the regulatory process, the Department for Energy and Mining - Energy Resources Division commissions independent assessments and reviews, and constantly monitors national and international research to ensure decision-making relies on scientific, professional and appropriate assessment of risk.

Links to key research projects and assessments relevant to in-situ gasification (commonly referred to as underground coal gasification) are provided below:

Key Findings of the Geomechanical Assessment of the proposed Leigh Creek UCG demonstration plant (PDF 140KB)	Ikon Science Geomechanical Model, Leigh Creek South Australia  (PDF 4.9MB)

• LLNL Underground Coal Gasification Review (PDF 5.9MB)
• LLNL Prevention of Groundwater Contamination from Underground Coal Gasification (PDF 7MB)
• LLNL Underground Coal Gasification: An Overview of Groundwater Contamination Hazards and Mitigation Strategies (PDF 7.4MB)
• Independent Scientific Panel Report on Underground Coal Gasification Pilot Trials (PDF 359KB)
• CSIRO Underground Coal Gasification: Evaluating Environmental Barriers (PDF 3.6MB)
• Underground coal gasification - Part 1: Field demonstrations and process performance (PDF 8.2MB)
• Field Investigation and Geotechnical Studies for UCG Feasibility Study Leigh Creek (PDF 2.6MB)
• Underground Gasification of Inaccessible Leigh Creek Coal Measures (PDF 4.9MB)
• In-situ Gasification of Coal for Electricity, Syngas and Synfuels (PDF 519KB)

Presentations

Presentations by the Department for Energy and Mining - Energy Resources Division in relation to underground coal gasification and/or the proposed Leigh Creek Energy in-situ gasification project are provided below.

Please note: these presentations are intended to provide general information on the Department for Energy and Mining - Energy Resources Division, its role and regulatory functions, and proposed or current licensee projects under the Petroleum and Geothermal Energy Act 2000 and associated regulations. Presentations should be considered in the context

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