EIS information guideline  Regulated structures
Regulated Structures are those dams, levees, or voids, located on a site which is conditioned under an
Environmental Authority, and which if improperly constructed, could have a serious or damaging impact on the
environment. Guidance on this is available at: http://www.ehp.qld.gov.au/land/mining/pdf/guide-structures-damslevees-mining-em634.pdf
Dams
The EIS should:
 list and describe all dams proposed to be constructed as part of the project. Relevant dams could be
Wastewater Dams, Tailings Dams, Water Supply Dams, Environmental Dams, Decant Dams, Process Water
Ponds, Treatment Ponds, Sediment Dams, Holding Dams, Release Dams, or Diversion Dams.
 use appropriately scaled maps and plans to show the locations of all dams
 provide details of the purpose and proposed contents of each dam
 provide details about the total area of land covered by the dam at full supply level, the maximum height of the
dam to the outside toe, the storage capacity at full supply level, and the total catchment area of the dam
 provide details about the location of the spillway, and the spillway discharge capacity
 use plans and maps to show the layout of the site, the locations of any infrastructure, buildings, or residences,
and features of environmental significance which could be affected by the construction, operation, or failure of
the dams.
To support the EIS, the planning for the project must be sufficiently advanced for a Consequence Category
Assessment to be undertaken for all proposed dams. The assessments must be undertaken for the three different
failure event scenarios described in EHP’s Manual for Assessing Consequence Categories and Hydraulic
Performance of Structures (EM635) https://www.ehp.qld.gov.au/land/mining/pdf/mn-mi-assess-haz-cat-hyd-perfdams-em635.pdf, i.e. for seepage, overtopping and dam break.
Consequence Category Assessment Reports, certified in accordance with Appendix C of the Manual, must be
included for all structures and the reports must state whether the structures are assessed as Low Consequence,
Significant Consequence, or High Consequence constructions.
The EIS should incorporate an assessment of the likely quality of water or wastewater in each dam, including an
assessment of the potential quality and quantity of contaminants in uncontrolled discharges or other controlled
releases which may occur. In particular:
 water quality estimates should be sufficiently accurate to be used as input into the Consequence Category
Assessment investigations
 where surface or groundwater environmental values may be significantly affected by seepage, “failure to contain
- seepage” assessments must include calculations of seepage rates with and without liners, volumes of
seepage, and of the total contaminant load potentially released in each case.
Dams which have been assessed to be in the Significant or High Consequence Category will be Regulated
Structures that are required to be designed by a Registered Professional Engineer in Queensland. The design,
construction, and operation of Regulated Structures in Queensland must conform to the requirements in the
Manual for Assessing Consequence Categories and Hydraulic Performance of Structures (EM635). Tailings Dams
must be constructed and operated in a manner consistent with the principles as set out in the ANCOLD Guidelines
http://www.ancold.org.au/?page_id=334 “Guidelines on Tailings Dams – Planning, Design, Construction, Operation
and Closure (May 2012)”, and “Guidelines on Dam Safety Management (August 2003)”.
EIS information guideline  Regulated structures
Levees
The EIS should:
 list and describe all levees (including bunds or banks) proposed to be constructed for flood control as part of
the project
 provide details about the location and length of the levees, including appropriately scaled maps and plans
 provide details about the height and cross-section of the levees at significant points, including the maximum
height
 provide details about the purpose of the levees, and about the mine infrastructure or the mining voids, or other
infrastructure the levee is designed to protect, and include maps and plans showing the ground level contours
across the site, and the flooded areas across the site for a range of Annual Exceedance Probabilities (AEPs) up
to the Probable Maximum Flood (PMF) Level. Plans showing inundated and flooded areas for the full range of
AEPs should be presented for the site layout and conditions before and after construction of the levees.
 provide details in maps and plans about the catchment areas and the runoff in the rivers, creeks, and drainage
paths, whose flood events are retained or excluded from the site by construction of the levees
 describe and illustrate where levees and final voids would lie at the end of mine operations in relation to flood
levels in adjacent streams, up to and including the PMF Level
 incorporate an assessment of the Consequence Category for levees in accordance with the manual EM635.
Using the principles outlined in EHP’s Manual for Assessing Consequence Categories and Hydraulic Performance
of Structures (EM635) determine and list in the EIS the Consequence Categories, whether Low, Significant, or
High, for all levees, bunds or banks proposed to be constructed. Consequence Category Assessment Reports,
certified in accordance with Appendix C of the Manual, should be included for all levees.
Final voids
Where voids are to be left on the mine site after closure and the completion of mining operations, the mine
development plan and the final closure plan must be formulated so as to protect final voids from inundation after
closure of the mine. This could be achieved by location of final voids in natural ground which is above the PMF
Level.
Where final voids are located below PMF Level, effective protection of the final void to a PMF level must be
provided and described in the EIS.
Final voids will accumulate water from groundwater ingress, local rainfall occurring on the void itself, and on any
contributing catchment surrounding the void. Final voids, which in the long term will generally contain very poor
quality water, should be formed and positioned to prevent overfilling from local rainfall and eventual overflow of
these voids.
The EIS should incorporate a water balance for proposed voids. It should also include a water quality model for the
water retained in the final void in respect of surface and groundwater inflows and evaporative loss and outflows.
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