A Generic Environmental Risk Assessment Framework for Deep-Sea Tailings Placement

75 Pages Posted: 16 Feb 2022

See all articles by Jennifer Lee Stauber

Jennifer Lee Stauber

affiliation not provided to SSRN

Merrin S. Adams

Government of the Commonwealth of Australia - CSIRO Health & Biosecurity

Graeme E. Batley

CSIRO Land and Water

Lisa A. Golding

Government of the Commonwealth of Australia - CSIRO Health & Biosecurity

Ian Hargreaves

affiliation not provided to SSRN

Luk Peeters

affiliation not provided to SSRN

Amanda Reichelt-Brushett

Southern Cross University

Stuart L. Simpson

CSIRO Land and Water

Abstract

Deep-sea tailings placement (DSTP) involves the oceanic discharge of tailings at depth (usually >100 m), with the intent of ultimate deposition of tailings solids on the deep-sea bed (>1000 m), well below the euphotic zone. DSTP discharges consist of a slurry of mine tailings solids (finely crushed rock) and residual process liquor containing low concentrations of metals, metalloids, flotation agents and flocculants. This slurry can potentially affect both pelagic and benthic biota inhabiting coastal waters, the continental slope and the sea floor. Building on a conceptual model of DSTP exposure pathways and receptors, we developed a stressor-driven environmental risk assessment (ERA) framework using causal pathways/causal networks for each of eight pelagic and benthic impact zones. For the risk characterisation, each link in each causal pathway in each zone was scored using four levels of likelihood (not possible, possible, likely and certain) and two levels of consequence (not material, material) to give final risk rankings of low, potential, high or very high risk. Of the 246 individual causal pathways scored, 11 and 18 pathways were considered to be of very high risk and high risk respectively. These were confined to the benthic zones in the mixing zone (continental slope) and the primary and secondary deposition zones. The new risk framework was then tested using a case study of the Batu Hijau copper mine in Indonesia, the largest DSTP operation globally. The major risk of DSTP is smothering of benthic biota, even outside the predicted deposition zones. Timescales for recovery are slow and may lead to different communities than those that existed prior to tailings deposition. We make several recommendations for monitoring programs for existing, proposed and legacy DSTP operations and illustrate how georeferenced casual networks are valuable tools for ERA in DSTP.

Keywords: causal networks, Metals, smothering, pelagic, benthic, recovery

Suggested Citation

Stauber, Jennifer Lee and Adams, Merrin S. and Batley, Graeme E. and Golding, Lisa A. and Hargreaves, Ian and Peeters, Luk and Reichelt-Brushett, Amanda and Simpson, Stuart L., A Generic Environmental Risk Assessment Framework for Deep-Sea Tailings Placement. Available at SSRN: https://ssrn.com/abstract=4033187 or http://dx.doi.org/10.2139/ssrn.4033187

Jennifer Lee Stauber (Contact Author)

affiliation not provided to SSRN ( email )

No Address Available

Merrin S. Adams

Government of the Commonwealth of Australia - CSIRO Health & Biosecurity ( email )

Graeme E. Batley

CSIRO Land and Water ( email )

Lisa A. Golding

Government of the Commonwealth of Australia - CSIRO Health & Biosecurity ( email )

Ian Hargreaves

affiliation not provided to SSRN ( email )

No Address Available

Luk Peeters

affiliation not provided to SSRN ( email )

No Address Available

Amanda Reichelt-Brushett

Southern Cross University ( email )

Stuart L. Simpson

CSIRO Land and Water ( email )

Brisbane
Australia

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