"Mine waste from Newcrest’ Lihir mine in Papua New Guinea is reducing ocean ecological diversity."

Awarding the great work of our community of writers, the WOW award highlights some the best impact analyses that week as voted for by our reviewing team. It might be particularly well written, focused on important topics or bringing an innovative angle to the subject, read on to find out who the winner is this week.

Deep-Sea Tailings Placement (DSTP) involves discharging of rock particles, residual solution, cyanide and dissolved metals^1;p3used in the mining process, directly into the ocean². Less than 20 of the world’s 2,500 mines use DSTP, impacting ecological diversity in the world’s coral reefs and marine life³as trace metals reduce the richness of marine communities². DSTP also poisons food chains from the accumulation of sediments and toxic metals². Papua New Guinea (PNG) is home to some of the most biodiverse habitats in the world⁴.

In PNG, the Lihir gold mine is 100% owned by Newcrest Mining since 2010⁵. Lihir produced 21,999 Kg of gold in 2020^6;p4.

In 2019, a local association accused Lihir of causing damage to the marine environment⁷. The mine has been operating DSTP since 1996^8;p1, discharging ≈100M tonnes of tailings slurry per year into the Pacific Ocean, which contains 2.5M t of sediment². This means from 1996-2020 (24 years) the mine generated ≈2.4bn t of tailings containing 60M t of sediment. Lihir has a projected life of 35 years⁹.

A 2015 study found the footprint of DSTP from Lihir is detectable up to 20 km east of the discharge and to at least 2,000 m water depth^8;p2. The DSTP is responsible for reduced abundances and changes in the higher-taxon composition of the sediment fauna^8;p7. Substantial loss of benthic fauna is significant down to 1,700 m, while macrofauna is severely impacted to at least 2000 m^8;p7.
Also, the physical stability of the seabed can be compromised for many years after DSTP has ceased, preventing ecological succession^8;p8. Improved tailing management would be possible to reduce impact, but the firm decided to forego these measures because they were not compulsory in PNG⁴.

Newcrest’ Lihir mine discharges 100M tonnes of tailings slurry into the ocean each year, impacting ecological diversity, up to 20 km of the discharge. Newcrest needs to implement alternative waste management methods and contribute to the regular monitoring of the seabed

Sources
1. http://documents1.worldbank.org/curated/pt/338021468284667602/pdf/827570WP0Extra00Guinea0ACS00PUBLIC0.pdf

2. https://www.mpi.org.au/2015/08/out-of-sight-out-of-mind-marine-mine-waste-disposal-in-papua-new-guinea/

3. https://www.reuters.com/article/mining-deep-sea-tailings-idUSL5N26V03S

4. https://ejatlas.org/print/lihir-mine-papua-new-guinea

5. https://www.mining-technology.com/projects/lihir-gold-mine/

6. https://www.newcrest.com/sites/default/files/2020-10/201005_Newcrest%20Annual%20Report.pdf

7. https://www.rnz.co.nz/international/pacific-news/380083/landowners-on-png-s-lihir-seek-compensation-for-water-usage

8. https://www.nature.com/articles/srep09985.pdf

9. https://terralingua.org/2015/07/09/mining-and-cultural-loss-assessing-and-mitigating-impacts-in-papua-new-guinea/

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