A full list of hazards has been generated for both coal mines and CSG operations, as described in Section 2.3.5.2.1 and Section 2.3.5.2.2. This section describes the scope of subsequent work, which addresses only a subset of the full list of hazards.
The hazards of primary focus from a BA perspective are those that extend beyond the development site and that may have cumulative impacts, as these are consistent with the regional focus of BA, and are where BA will add value beyond site-specific environmental impact statements (EIS). Ultimately, however, BAs need to be able to address all identified hazards by considering the scope, modelling, other literature or narratives, and specifying where science gaps may exist.
BAs are constrained by considering only impacts that can happen via water, and so hazards such as dust, fire or noise are deemed out of scope and are addressed by site-based risk management unless there is a water-mediated pathway.
In general, leading practice is assumed and accidents are deemed to be covered adequately by site-based risk management procedures and are beyond the scope of BA; for example, the failure of a pipeline is covered by site-based risk management. However, for the Maranoa-Balonne-Condamine subregion, hazards associated with the ‘exploration and appraisal’ and ‘construction’ phases of CSG operations are considered in scope -- even those hazards associated with human error and accidents. These hazards are deemed in scope because activities in this phase (such as hydraulic fracturing and drilling) occur at sufficient scale and frequency to require further consideration in this BA.
Hazards that pertain to the development site and with no off-site impacts are important to acknowledge but will typically be addressed by site-based risk management procedures.
For CSG operations, the following hazards are considered out of scope for further analysis as part of the BA of the Maranoa-Balonne-Condamine subregion because they are deemed to be covered by site-based risk management and regulation:
- abandonment practice
- hazards addressed by site management, no water-mediated pathway (dust, fire or noise)
- containment failure due to construction or design
- disruption of surface drainage network for site-based infrastructure, plant and facilities, roads, creek crossings
- equipment/infrastructure failure (e.g. pipeline failures)
- leaching/leaking from storage ponds and stockpiles
- spillages and disposals (diesel, mud, cuttings, fluid recovery)
- vegetation clearance and subsequent soil erosion following heavy rainfall.
Figure 31 and Table 15 describe all hazards associated with CSG operations that are considered to be in scope in the Maranoa-Balonne-Condamine subregion. The hydrological effect of an activity such as ‘water and gas extraction’ depends on the impact cause and impact mode. For example, ‘depressurisation’ (impact cause) that causes ‘subsidence’ (impact mode) affects ‘surface water direction’ (hydrological effect) and ‘aquitard leaks’ (impact cause) that cause ‘non-target, non-reservoir aquifer depressurisation’ (impact mode) affects ‘groundwater pressure’ (hydrological effect) (Figure 31).
Hydrological effects associated with CSG operations that are considered to be in scope in the Maranoa-Balonne-Condamine subregion are shown in Figure 31 and listed below:
- surface water quality
- surface water direction
- surface water flow
- groundwater quality
- aquifer properties
- groundwater composition
- groundwater flow (reduction)
- groundwater level
- groundwater pressure.
Impact causes are underlined, impact modes are bold and activities are bullet points. Arrows indicate the spatial context for each hazard: aquifers, aquifer outcrop areas, watercourses, catchments.
GDEs = groundwater-dependent ecosystems, groundwater composition = mixing groundwaters of different composition (in terms of natural dissolved solids)
Typology and punctuation are consistent with the hazard analysis dataset (Bioregional Assessment Programme, Dataset 1)
Table 15 Hazards identified for the life-cycle stages of coal seam gas operations that are considered to be in scope in the Maranoa-Balonne-Condamine subregion and their associated hydrological effects, spatial context, temporal context, and potentially impacted assets or ecosystems
This table lists each hazard (with its spatial and temporal context) in a chain of logic from hydrological effects to potentially impacted assets or ecosystems. The spatial context includes target and non-target aquifers, aquifer outcrop areas, coal resource development tenements and watercourses. Within the relevant spatial and temporal context, assets and ecosystems are described using landscape classification rule sets (GAB GDEs, non-GAB GDEs), landscape class group (e.g. ‘Floodplain or lowland riverine (including non-GAB GDEs)’) or asset type (e.g. economic = economic groundwater asset).
aLife-cycle stage of coal seam gas operations where C = construction, D = decommissioning, E = exploration and appraisal, P = production
bshort term = less than 5 years, medium term = 5 to 10 years, long term = 10 to 100 years
CSG = coal seam gas, GAB = Great Artesian Basin, GDEs = groundwater-dependent ecosystems, GW = groundwater, SW = surface water, GW composition = mixing groundwaters of different composition (in terms of natural dissolved solids)
Typology and punctuation are consistent with the hazard analysis (Bioregional Assessment Programme, Dataset 1)
Data: Bioregional Assessment Programme (Dataset 1)
For open-cut coal mines, the following hazards are considered out of scope in the Maranoa-Balonne-Condamine subregion because they are deemed to be covered by site-based risk management and regulation and do not have cumulative effects on water in the subregion:
- addressed by site management, no water-mediated pathway (dust, fire or noise)
- bore and well construction (integrity, leakage)
- disruption of surface drainage network for site-based infrastructure, plant and facilities, roads, creek crossings
- equipment/infrastructure failure (e.g. pipeline failures, plant failures)
- leaching/leaking from storage ponds and stockpiles
- loss of containment (due to construction or design, slope failure)
- re-contouring, compaction and settlement following backfill
- spillages and disposals (diesel, mud, cuttings, fluid recovery)
- vegetation clearance and subsequent soil erosion following heavy rainfall.
Of those hazards that are in scope, some will be addressed by the BA numerical modelling, while others (e.g. water quality hazards) will be assessed qualitatively, using the logic and rule-sets described in the conceptual model of causal pathways. The hazard priority number or hazard scores indicate the relative importance of the hazard. Hazards with low scores are of lower priority.
Figure 32 and Table 16 describe all hazards associated with coal mining developments that are considered to be in scope in the Maranoa-Balonne-Condamine subregion. The hydrological effect of an activity such as ‘water management structures’ depends on the impact cause and impact mode. For example, the hydrological effect of ‘poor handling / management’ (impact cause) can cause ‘excessive runoff during closure’ (impact mode) that affects ‘surface water quality and groundwater quality’ (hydrological effects) and ‘diverting site drain line’ (impact cause) can cause ‘disruption of natural surface drainage’ (impact mode) that affects ‘surface water volume / quantity, surface water quality and groundwater quantity / volume’ (hydrological effect). Hydrological effects associated with coal mines that are considered to be in scope in the Maranoa-Balonne-Condamine subregion are shown on Figure 32 and listed below:
- surface water quality
- surface water direction
- surface water flow
- surface water volume
- change to zero flow days
- groundwater quality
- groundwater direction
- groundwater flow (reduction)
- groundwater quantity/volume
- groundwater pressure.
Impact causes are underlined, impact modes are bold and activities are bullet points. Arrows indicate the spatial context for each hazard: aquifers, aquifer outcrop areas, watercourses, catchments.
GDEs = groundwater-dependent ecosystems
Typology and punctuation are consistent with the hazard analysis (Bioregional Assessment Programme, Dataset 1).
Table 16 Hazards identified for the life-cycle stages of open-cut coal mines that are considered to be in scope in the Maranoa-Balonne-Condamine subregion and their associated hydrological effects, spatial context, temporal context, and potentially impacted assets or ecosystems
This table lists each hazard (with its spatial and temporal context) in a chain of logic from hydrological effects to potentially impacted assets or ecosystems. The spatial context includes target and non-target aquifers, aquifer outcrop areas, coal resource development tenements and watercourses. Within the relevant spatial and temporal context, assets and ecosystems are described using landscape classification rule sets (GAB GDEs, non-GAB GDEs), landscape class group (e.g. ‘Floodplain or lowland riverine (including non-GAB GDEs)’) or asset type (e.g. economic = economic groundwater asset).
aLife-cycle stage of coal mine where C = mine closure, D = development, E = exploration and appraisal, P = production, R = rehabilitation
bMedium term = 5 to 10 years, long term = 10 to 100 years
GAB = Great Artesian Basin, GDEs = groundwater-dependent ecosystems,GW = groundwater, SW = surface water. Typology and punctuation are consistent with the hazard analysis (Bioregional Assessment Programme, Dataset 1).
Data: Bioregional Assessment Programme (Dataset 1)
