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Goldmine! Dr Arthur White, explains his work for an Australian mining company that had to deal with a threatened species, the pink-tailed worm lizard. The pink-tailed worm lizard is a small, skinny burrowing lizard that has no legs. It’s about 10-15cm and looks like an animated shoelace when you see it. It is a highly specialised carnivore, only eating the pupae and eggs of a couple of species of ants. The lizards crawl down the ant tunnels and enters the brood chamber inside the ant nest where the eggs and pupae are held. They have to get their meal the soldier ants realise that a predator is in the brood chamber and descend on the worm-lizard and drive it out. The lizard is listed as a threatened species with a very small population located on the Murrumbidgee River close to the ACT border.
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| Aprasia
As the years went by odd individuals were found further south and west. In 2001 one of the lizards was found on a site being pegged out for a rare earth mine at Toongi about 30km south of Dubbo. The mining company, Alkane Resources and its Dubbo Zirconia Project, was after the rare earth metals niobium, erbium, yttrium and zirconium.
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The mining company, Alkane Resources and its Dubbo Zirconia Project, was after the rare earth metals niobium, erbium, yttrium and zirconium. These are formed when deep earth lavas come to the surface. The ones at Toongi formed during the Jurassic period and, trapped by a harder layer near the surface, the lavas spread sideways making laccoliths. When the hardened layer eroded away trachytes were formed. Six trachytes were drilled, one showed economic amounts of the rare earth metals. Niobium, for instance, fetches $180 thousand per gram! Alkane Resources took 10 years to formulate a development plan and get financing, even knocking back Chinese offers (the Chinese like to control world prices).
In 2012 the company engaged Dr White to find out exactly what was going on with the pink-tailed worm lizards so that planners could work out how to develop the site while avoiding critical habitat areas. For three years Dr White flipped over rocks to find the lizards and gathered data on the vegetation, soil type and rock types found.
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| This created a series of habitat descriptors across a large region. The variables of vegetation, soil and rock types were looked at independently and in conjunction with each other. There was very weak associations with vegetation and presence of worm-lizards and with soil type.
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It seems that as trachytes erode they mix with the local Permian sandstone making a soil critical to both the ants and the lizards. The best overlay, however, was the geological one. When the trachytes weathered they did so by onion peeling, the layers ending up as shards on the soil. It was these shards that the lizards used in spring and autumn as shelter when they came close to the surface. Since one of the trachytes was going to be mined Dr White then looked at ways to offset that habitat loss.
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Several truckloads of old roof tiles were set up in ten clusters. They were either laid out in single file or in blocks of four and were then monitored. The tiles influenced the soil temperature and soil humidity, particularly under the blocks of four tiles.
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| Shed skin
A lot of animals used the tiles (geckos, centipedes, millipedes, grasshoppers) and within six months the pink-tailed worm lizards were also living there. This had the potential to create even more habitat than was going to be lost.
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The company has worked hard to avoid the other worm-lizard habitat areas and is currently doing large-scale habitat recreation. It is a great example of what can be done when a mining company works with scientists.
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| array with ten tiles
For the company and the lizard the project has turned out to be a goldmine!
Did You Know? Mining 20 ton of rock each year creates 200gms of niobium, 180gms of erbium, 60gms yttrium and 700gms of zirconium.
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Dr Arthur White was interviewed for A Question of Balance by Ruby Vincent. Images supplied by Dr White. Summary text by Victor Barry June 2018.
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