Asbestos is a nasty old mineral. It’s known for releasing fine, microscopic fibers that can lodge in the body’s tissues and cause deadly disease over a period of decades. Originally prized for its fire resistance and insulating properties, it was widely used in all sorts of building materials. Years after the dangers became clear, many countries eventually banned its use, with strict rules around disposal to protect the public from the risk it poses to health.

Australia is one of the stricter countries when it comes to asbestos, taking great pains to limit its use and its entry into the country. This made it all the more surprising when it became apparent that schools across the nation had been contaminated with loose asbestos material. The culprit was something altogether unexpected, too—in the form of tiny little tubes of colored sand. Authorities have rushed to shut down schools as the media asked the obvious question—how could this be allowed to happen?

Hiding In Plain Sight

Australia takes asbestos very seriously. Typically, asbestos disposal is supposed to occur according to very specific rules. Most state laws generally require that the material must be collected by qualified individuals except in minor cases, and that it must be bagged in multiple layers of plastic prior to disposal to avoid release of dangerous fibers into the environment. The use, sale, and import of asbestos has been outright banned since 2003, and border officials enforce strict checks on any imports deemed a high risk to potentially contain the material.

Thus, by and large, you would expect that any item you bought in an Australian retailer would be free of asbestos. That seemed to be true, until a recent chance discovery. A laboratory running tests on some new equipment happened to accidentally find asbestos contamination in a sample of colored sand—a product typically marketed for artistic use by children. The manager of the lab happened to mention the finding in a podcast, with the matter eventually reaching New Zealand authorities who then raised the alarm with their Australian counterparts. This led to a investigation by the Australian Competition and Consumer Commission (ACCC), which instituted a national safety recall in short order.

The response from there was swift. At least 450 schools instituted temporary shutdowns due to the presence or suspected presence of the offending material. Some began cleanup efforts in earnest, hiring professional asbestos removalists to deal with the colored sand. In many cases, the sand wasn’t just in sealed packaging—it had been used in countless student artworks or spilled in carpeted classrooms. Meanwhile, parents feared the worst after finding the offending products in their own homes. Cleanup efforts in many schools are ongoing, due in part to the massive spike in demand for the limited asbestos removal services available across the country. Authorities in various states have issued guidelines on how to handle cleanup and proper disposal of any such material found in the workplace.

At this stage, it’s unclear how asbestos came to contaminate colored sand products sold across the country, though links have been found to a quarry in China. It’s believed that the products in question have been imported into Australia since 2020, but have never faced any testing regarding asbestos content. Different batches have tested positive for both tremolite and chrysotile asbestos, both of which present health risks to the public. However, authorities have thus far stated the health risks of the colored sand are low. “The danger from asbestos comes when there are very, very fine fibres that are released and inhaled by humans,” stated ACCC deputy chair, Catriona Lowe. “We understand from expert advice that the risk of that in relation to these products is low because the asbestos is in effect naturally occurring and hasn’t been ground down as such to release those fibres.”

Investigations are ongoing as to how asbestos-containing material was distributed across the country for years, and often used by children who might inhale or ingest the material during use. The health concerns are obvious, even if the stated risks are low. The obvious reaction is to state that the material should have been tested when first imported, but such a policy would have a lot of caveats. It’s simply not possible to test every item that enters the country for every possible contaminant. At the same time, one could argue that a mined sand product is more likely to contain asbestos than a box of Hot Wheels cars or a crate of Belgian chocolates. A measured guess would say this event will be ruled out as a freak occurrence, with authorities perhaps stepping up random spot checks on these products to try and limit the damage if similar contamination occurs again in future.

Featured image and other sand product images from the Australian government’s recall page.

In Dune, the Fremen people of Arrakis practice an odd future hybrid religion called “zensunni.” This adds an extra layer of meaning to the title of [Mark Rehorst]’s Arrakis 3.0 sand table, given that the inspiration for the robotic sand table seems to be Zen gardens from Japan.

The dunes on the tabletop version of Arrakis owe nothing to sand worms, but are instead created a rolling metal ball. With all workings happening below, it looks quite magical to the uninitiated, but of course it’s not magic: it’s magnets. Just beneath the tabletop and its sands, the steel ball is being dragged along by the magnetic field of a powerful neodynium magnet.

That magnet is mounted in a CoreXY motion system that owes more than a little bit to modern 3D printers. Aside from the geometry, it’s using the standard G6 belt we see so often, along with a Duet3D mainboard, NEMA 17 steppers, and many 3D printed parts to hold its aluminum extrusions together. Thanks to that printer-inspired motion system, the ball can whirl around at 2000 mm/s, though [Mark] prefers to run slower: the demo video below shows operation at 1000 mm/s before the sand has been added.

This build was designed for ease of construction and movement: sized at 2’x4′ (about 61 cm x 122 cm), it fits through doors and fits an off-the-shelf slab of coffee table glass, something that [Mark] wishes he’d considered when building version two. That’s the nice thing about jumping in on a project someone’s been iterating for a while: you’ve got the benefit of learning from their mistakes. You can see the roots of this design, and what has changed, from the one he showed us in 2020. 

Naturally you’re not limited to CoreXY for a sand table, though it is increasingly popular — we’ve seen examples with polar mechanisms and even a SCARA arm.