Earth and Environmental Science

30 November 2020

GEOL 5903 Seminar: Peter Opra
Title: Is Marine Tailings Disposal in Fjords an Acceptable Alternative for Base Metal Mining?
Time: 2:30 p.m. - 3:30 p.m.
Presentation via TEAMS.
Abstract:
The process of Marine Tailings Disposal (MTD), that is, discharging tailings directly into the marine environment, is controversial. The knowledge gaps in the research for site-specific applications pose environmental risks such as loss of marine life and permanent alteration of the benthic habitat. The latter two can be attributed to the toxicity resulting from the trace metals accumulating in the environment, as well as the adaptability of opportunistic species. Arguments have been made that MTD is effective at mitigating Acid Rock Drainage (ARD) and mitigating the land suitability complications faced with constructing tailings impoundments, and that it is economically beneficial. In contrast, others emphasize the adverse environmental impacts that MTD may cause. It is known that MTD lowers the risks associated with geohazards and excess precipitation. However, in doing so MTD potentially smothers habitat, decreases biodiversity, and introduces heavy metals and dangerous elements (e.g., Pb, Zn, As, Hg) to aquatic biota. Due to the nature of water stratification possible in fjords presenting sulphide-reducing conditions, MTD in northern Norway for the Nussir copper deposit may be acceptable. With further site-specific studies, the knowledge gaps can be addressed. Therefore, with a better understanding of the effect and resulting impact of MTD, mitigating the severity of the impact becomes more possible.