Pioneer-Burdekin geotechnical investigation works – Where are we up to?

In July 2023, we started important technical investigation works around the proposed Pioneer- Burdekin Pumped Hydro Project (the proposed Project) site. The purpose of these investigations is to help us better understand what lies beneath and on top of the ground of the proposed Project site so that the Queensland Government can make a final decision.

As of September 2023, we are in the technical investigation phase gathering critical information about the proposed project site. If the project is given the go ahead, the findings from these investigations will help us to avoid, minimise, and offset potential adverse impacts to local ecosystems and the environment. 

There are a number of phases that a project this large must go through before it can be given the go ahead. 

To date, more than 500 metres of core samples have been collected and logged from 10 sites across the proposed upper and lower reservoirs. These and future samples will be sent to a team of geologists for analysis.

We have also commenced drilling the first deep geotechnical hole. Deep drilling investigations are focused on understanding the condition of the ground at greater depths, especially in areas where proposed underground caverns and tunnels may be built. Based on conceptual designs, these underground structures are proposed to be situated approximately 700 to 750 metres below the surface. 

To better understand what animal and plant species may be present across the proposed project site, we have ecologists, including an aquatic and terrestrial ecologist, conducting a number of investigations across the different landscapes and bodies of water that make up the proposed project site. 

These technical investigations are expected to continue into early 2024. 

Why are we undertaking technical investigations?

Geological, hydrological and ecological investigations are crucial prior to building a pumped hydro dam for several important reasons: 

Site selection:  

Geological surveys help identify suitable locations for the dam. Certain geological features such as stable rock formations, low permeability, and appropriate topography are essential for the construction and long-term stability of a pumped hydro dam.

Foundation assessment:  

The geological investigations assess the suitability of the dam's foundation materials. Engineers need to ensure that the foundation can support the weight of the dam and resist deformation or settlement over time. Detailed geological studies help determine the type and quality of rock or soil beneath the dam site. 

Seismic risk assessment:  

Pumped hydro dams must be designed to withstand seismic events. Geological investigations help in evaluating the seismic risk in the area and designing the dam accordingly to mitigate potential earthquake-induced damage. 

Water source assessment:  

Geological surveys can also help identify potential water sources that can be used for the proposed Project. Understanding the hydrogeology of the area is important for sustainable water management. 

Tunnel and underground cavern suitability:  

If given the go ahead, the Project will involve the construction of tunnels or underground caverns to store water. Geological investigations are essential to assess the stability and suitability of these underground structures, as well as the surrounding rock conditions. 

Environmental impact assessment:  

Ecological studies can help evaluate the potential environmental impacts of the dam construction on local ecosystems and groundwater resources. This information is crucial for obtaining the necessary environmental approvals. 

Water seepage and leakage assessment:  

The geological characteristics of the subsurface can affect water seepage and leakage from the dam reservoir. Detailed investigations can help design effective liners and measures to prevent water loss. 

Risk mitigation:  

By understanding the geological conditions, engineers can design the dam and associated infrastructure with appropriate safety measures to mitigate geological risks, such as landslides, erosion, and subsidence. 

Cost estimation:  

Accurate geological data is essential for cost estimation. Unexpected geological challenges can significantly impact the Project's budget, so a thorough understanding of the geological conditions is vital for financial planning. 

What happens next?

The findings from these technical investigations findings will then feed into a detailed analytical report (DAR) which will then be presented to the Queensland Government for consideration. If the proposed Project proceeds to an environmental impact statement, we will prepare more detailed studies which will include extensive additional field surveys. As is the norm for substantial projects in Australia, progress on the project can only occur once the environmental approvals have been secured. 

Given that we are in the initial investigative phase of this proposed Project, we are committed to methodically working through each project phase to ensure that we understand the potential geological, hydrological, environmental and community impacts and opportunities. 

As we progress through each phase of the project, and more answers come to light, we are committed to communicating these with our Pioneer and Burdekin communities via our regular Community Information Sessions, quarterly newsletter and social media accounts. 

If you have questions about these technical investigations, please contact our team via [email protected] 

Published 27 September 2023.