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Unexpected Non-acid Drainage from Sulfidic Rock Waste
Andrea R Gerson1, Peter J Rolley2, Catherine Davis2
1Blue Minerals Consultancy, Wattle Grove, Tasmania, Australia. Andrea@bluemineralsconsultancy.com.au.
Scientific Reports
|March 15, 2019
Summary
Standard acid-base accounting tests may misclassify waste rock potential for acid mine drainage (AMD). New methods analyzing mineralogy accurately redefine waste rock, improving environmental planning for mining and construction sites.
Area of Science:
- Environmental Science
- Geochemistry
- Mineralogy
Background:
- Acid mine drainage (AMD) poses significant environmental risks at rock extraction sites.
- AMD prediction and management rely on acid-base accounting (ABA) tests for sulfide-bearing materials.
- Standard ABA tests may misclassify waste rocks with low sulfide and carbonate content.
Purpose of the Study:
- To evaluate the accuracy of standardized ABA tests for AMD classification.
- To investigate the influence of mineralogy on AMD potential in waste rocks.
- To develop improved methods for AMD risk assessment in mining operations.
Main Methods:
- Application of standard ABA tests to waste rock samples from a South Australian copper mine.
- Detailed mineralogical analysis of sulfide and silicate minerals.
- Re-evaluation of weathering reactions based on comprehensive mineralogical data.
Main Results:
- Standard ABA tests incorrectly classified some waste rock as potentially acid forming.
- Mineralogical analysis revealed that silicate dissolution neutralizes acid generation.
- Field observations were consistent with silicate dissolution exceeding acid generation rates.
Conclusions:
- Standard ABA tests have limitations for waste rocks with specific mineralogies.
- A comprehensive mineralogical approach provides more accurate AMD classification.
- Developed methods enhance environmental planning and cost-effectiveness for mine waste management.
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