Back before the GFC I was a newly fledged rigger, and perhaps a little naïve to the ways of operational mine sites, let alone what things would be like at Ranger.
But I’d done a few shutdowns before, including the furnace floor rebuild at the smelter in Kambalda, and was very keen to be sent up to see the Northern Territory and get paid at the same time.
Being Adelaidian, my blood is too thick for such heady northern climes, by which I mean the steamy regions beyond the tropic of Capricorn.
Given the choice, I tend to prefer my air desert-dry, so the wall of humidity that met me at the doorway of the Darwin airport was like an atmospheric quagmire; to breathe it seemed much more viscous than clement air of Perth
It was January – Welcome to the tropics, son.
The job was to clean out one of the CCD (Counter-Current Decantation) tanks, ready for inspecting and repairing the rubber lining, and to change pump impellers underneath the tank.
A CCD tank is like an enormous, open-topped butter churn, but rather than mastitus-ridden, bovine squeezings, the tank is filled with a mixture of milled ore, water, some kind of flocculant (guar gum, maybe) and of course, sulphuric acid.
If I remember correctly, the acid comes from the leach tanks where the ore sits for a while so that the uranium can dissolve into solution, then that solution is decanted in the CCD tank where the flocculant is frothed up so that it can bond with the uranium and float to the surface, turning the whole lot into one big, bubbly, radioactive milkshake.
Of all the tanks only one of them was shut down so that we could do maintenance, and judging by the look of them, we were the first guys to take on this job in a very long time.
Once drained, the tank was one or two feet deep in the extremely heavy ore slurry and the arms were piled with sulphur sediment, hard as sandstone.
We needed to disconnect the pumps below and hose all the sludge down the drainhole in the middle, a task that we were instructed to do with process water.
Now, process water… little did I know that’s the water that was used to “process” the ore… duh.
This means the water contained traces of the uranium in solution, fully dissolved and ready to soak into porous, human skin.
Although we wore gumboots, long gloves and faceshields, naturally we wound up completely soaked after a few minutes of waving a two inch fire hose on high pressure, trying in vain to get the dense rock sediment to lift up and go down the drain.
It took four weeks to clean one tank, and that included digging out the gutter around the top of the tank from a scissor lift, as well as smashing all the piled up sulphur residue off the enormous arms of the churn (crawling around the lattice structure with a gympie hammer, bashing our way through and getting covered in the yellow muck).
If this sounds like a horrifying degree of physical contact with some very noxious material, you’d be right.
It was about two weeks into the job that management finally got around to giving us our radiation inductions.
There I learned that the water with which I’d been soaking myself was actually radioactive, and you shouldn’t let it get on your skin!
We couldn’t know the degree of radiation we faced, as we weren’t issued with personal radiation monitors (not necessary for shutdown crews, we were told) but workers would reassure us that it wasn’t much.
The next week I took myself to the radiation lab during lunch, where the radiation officers expressed bemusement, then horror when I told them that the grey material all over my shirt was ore.
A quick sweep with the scintillometer revealed slow ticking over my body, which was reassuring, but my leather boots crackled like static on a black and white TV.
They were, as they say in the uranium game, “hot”, and were promptly discarded and replaced with a fresh pair from the stores, along with a full complement of new socks.
Since then friends have asked me if I gained any super powers in that tank.
Although I was offered another month of work at Ranger to shutdown another CCD tank, I declined the offer, perhaps a little too politely for the response it deserved.
Leaving alone the forgetfulness of management when it came to educating a shutdown crew about the full extent of radioactive hazards, Ranger’s production plant was in pretty bad shape, even to my uneducated eye – It was like the mine that time forgot.
There was gridmesh rusted out, full of holes in some spots, so you really had to watch your step on the stairs and catwalks, not to mention the rotted-out, RSJ beams, steel nearly two inches thick you could push a screwdriver through.
I guess that’s what happens when you have sulphuric acid fumes mixing with the sultry, jungle atmosphere- It rots the steel away from under you.
I don’t know whether the site was under-maintained or not, but the fact that a leach tank actually busted open and spilled a full load of radioactive acid slurry last year is a pretty bad sign.
It’s good that ERA is replacing the baffle supports in all the leach tanks, but that kind of corrosion incident points to the prospect that the Ranger plant will be up for a lot more maintenance than that.
It makes me wonder what could happen if ERA were allowed to start a new mine expansion?
Would they look after it? Or would it simply rot away over the years, mismanaged and scraping by on the barest minimum of maintenance?
What do I know? I’m just a simple rigger.