Materials characterisation information is required for the preparation of Mining Proposals and Mine Closure Plans. But why is materials characterisation so important?
Acidic and/or Metalliferous Drainage (AMD) is commonly cited as one of the biggest risks to the mining industry. Similarly use of inappropriate materials for landform construction commonly results in excessive erosion, which can lead to poor rehabilitation performance and large remediation costs. The importance of materials characterisation* to minimise these risks has been highlighted recently with a number of presentations at the Mine Closure 2016 conference and the release by the Department of Mines and Petroleum (DMP) of Draft Guidance Materials Characterisation Baseline Requirements for Mining Proposals.
At the Mine Closure 2016 conference, two sessions were dedicated to the topics of:
- soils for mine closure
- geochemistry and mine waste.
In addition, materials characterisation also formed the basis for many of the presentations in the sessions on landform design and rehabilitation, and ecosystem reconstruction and revegetation. Some of the areas covered by the presentations at the conference included:
- the complexities of assessing the physical characteristics of waste rock and how to undertake this on already dumped material
- use of process flow diagrams to classify waste rock and avoid classifying lots of samples as uncertain with respect to AMD potential
- availability and properties of overburden and interburden materials that may be used as total or partial soil substitutes in rehabilitation and classification based on pH, salinity and sodicity.
More detail on each of the presentations at the Mine Closure 2016 conference is included in the proceedings which will available for purchase from the Australian Centre for Geomechanics.
The DMP Draft Guidance Materials Characterisation Baseline Data Requirements for Mining Proposals identifies that materials characterisation is a critical component of mine planning that helps to ensure that risk assessment is appropriately informed and aids in the responsible mine closure planning. The guidance provides detailed information on the sampling requirements and recommended analyses for a range of factors including:
- AMD (encompassing all metals/metalloids regardless of ether the conditions are acidic)
- saline materials and/or drainage
- sodic and/or dispersive material
- erosive material
- material with other chemical/physical properties that will affect stability of rehabilitation (such as low pH, low fertility, poor structural integrity)
- fibrous materials
- naturally occurring radioactive material.
The DMP Draft Guidance Materials Characterisation Baseline Data Requirements for Mining Proposals is available on the DMP website and is open for public comment until Friday 29 April 2016.
* Materials characterisation is defined by the DMP as the identification of the physical and geochemical properties of materials and classification of them as to whether they have the potential to cause environmental harm, or contribute to, or detract from, success of rehabilitation and closure.
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