"Mine waste from Newcrest’ Lihir mine in Papua New Guinea is reducing ocean ecological diversity."
The Impaakt Team
7 min Read Time | April 7th 2021
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"A very informative piece giving the reader a better understanding of one of the many environmental impacts that mining has. Revealing the consequences of mining by-products is essential and regrettably in this case we can see more clearly the impact this has on ocean ecological diversity."
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“Mine waste from Newcrest’ Lihir mine in Papua New Guinea is reducing ocean ecological diversity.”
Deep-Sea Tailings Placement (DSTP) involves discharging of rock particles, residual solution, cyanide and dissolved metals1;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 20206;p4.
In 2019, a local association accused Lihir of causing damage to the marine environment7. The mine has been operating DSTP since 19968;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 depth8;p2. The DSTP is responsible for reduced abundances and changes in the higher-taxon composition of the sediment fauna8;p7. Substantial loss of benthic fauna is significant down to 1,700 m, while macrofauna is severely impacted to at least 2000 m8;p7. Also, the physical stability of the seabed can be compromised for many years after DSTP has ceased, preventing ecological succession8;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