Ore grade decrease as life cycle impact indicator for metal scarcity: the case of copper
Marisa D M Vieira1, Mark J Goedkoop, Per Storm
1PRé Consultants bv, Printerweg 18, NL-3821 AD Amersfoort, The Netherlands. vieira@pre-sustainability.com
Environmental Science & Technology
|November 1, 2012
Summary
This study introduces a novel method using global ore grade data to better assess metal resource extraction impacts in life cycle assessments (LCA). The new characterization factors (CFs) improve the evaluation of metal scarcity in product life cycles.
Area of Science:
- Environmental Science
- Resource Management
- Industrial Ecology
Background:
- Current life cycle assessment (LCA) methods inadequately address metal resource scarcity.
- A robust approach is needed to quantify the environmental importance of metal extraction.
Purpose of the Study:
- To develop and validate a new method for assessing metal resource extraction impacts in LCA.
- To derive characterization factors (CFs) based on global ore grade information and cumulative grade-tonnage relationships.
Main Methods:
- Utilized global ore grade data to establish cumulative grade-tonnage relationships.
- Derived characterization factors (CFs) for copper extraction from different deposit types.
- Investigated the influence of CF models (marginal vs. average), mathematical distributions (loglogistic vs. loglinear), and reserve estimates (ultimate reserve vs. reserve base).
Main Results:
- Characterization factors were derived for porphyry, sediment-hosted, and volcanogenic massive sulfide copper deposits.
- Sensitivity analyses showed that model choice and reserve estimates significantly influence CF values, particularly for average CFs.
- Marginal CFs showed smaller variations compared to average CFs across different parameters.
Conclusions:
- Cumulative grade-tonnage relationships provide a valuable tool for assessing the relative importance of metal extraction in LCA.
- The proposed method offers a more nuanced understanding of metal resource depletion impacts compared to preliminary approaches.
- Further research can refine these factors for broader application in environmental impact assessments.
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