There's something happening here, what it is ain't exactly clear, I say hey now, what's that sound, everbody look what's going down.
Of respirators, H2S and respiratory protection;
Typical HPAL process flowsheet, page 8 ozemail.com.au
Stage 5, flash tanks
Stage 6, precipitation
Murrin Murrin process flow sheet
anaconda.com.au
Mixed sulphide neutralization, hydrogen sulphide (H2S) precipitation.
news.com.au
Five workers injured in gas leak.
A major gas leak knocked 5 workers unconscious at Anaconda's MM mine. 2 workers were flown from Leonora to Perth and were in stable condition, 3 others are under observation.
Union officials said today they were trying to travel to the mine, to talk to the workers.
"The gas leak was caused by a temporary power failure venting H2S into the area where the men were working."
"Anaconda and the Dept. of Minerals and Energy will be conductiong an investigation to prevent a repeat of today's incident."
According to Twiggy Forrest, that will only take a couple of days.
[If I were a worker, this part would really piss me off]
"Mr. Forrest said it appeared that the actions of the workers themselves may have resulted in their being affected by the gas. 'In such a situation, an alarm sounds, and each person is issued with a gas mask who may be in any possible affected area'.
'Those masks were not applied-the personnel chose to vacate the area immediately, but unfortunately some did suffer some temporary gas toxicity in the process.'
And then:
theage.com.au
Anaconda douses gas leak concern:
Production at MM would be unaffected by a major gas leak, the mining company said. Twiggy Forrest said his company's plant was still operating ant lony the area of the gas leak was under investigation. "It has not affected the performance of the plant."
Mr. Forrest said the first autoclave with the new top-entry flash system had been started. "I would like to see how that settles down before I can you any production forecasts we can rely on."
"You can't view it as a production program. The plant's in start up mode, it's not a bottleneck halfway through the plant or in the middle of the plant, it's a bottleneck at the start of the plant. And until that flash vessel is resolved with the proven technology, which has been implemented on one and in now being implemented on the remaining vessels, I can't say whether it's working at 10% or 20% or whatever.
Ok, now for the serious questions:
1) Anaconda replaces bottom entry flash vessel which doesn't work with flash vessel top entry which may work. Anaconda makes Fluor eat the cost. (step 5). Step 6, H2S precipitation leads to near fatal accident. Is the new flash vessel design causative of the gas leak? Or is the temporal relationship coincidence.
2) H2S is a known asphyxiant gas. Most poisonings are seen in natural gas wells, (drill hits pocket of methane and H2S), sewers, and manure pits. Due to its high toxicity most industrial users are extremely careful. How many of you believe that a ventilation system failed allowing gas to build up in a work area. From 5 ppm to 150 ppm it smells like rotten eggs and at 50 ppm it is a eye irritant. Above 150 ppm your olfactory nerve is paralyzed (no odor). So there was no slow build up of the gas, allowing egress from the building but rather a catastrophic failure leading to loss of consciousness, eg 700 ppm. To work safely (e.g. perform extraction) in this area you would need a tank or air hose supplied full face positive pressure respirator, not a 1/2 face dual cartridge negative pressure respirator.
So the workers now know that there lives are in danger, and they know that Twiggy is blaming them and not taking the problem seriously. The union is feeling the heat. Aurum will have to fill us in as to whether the Dept. of Minerals and Energy is a lap dog of Anaconda, or whether they are interested in worker production.
I'll agree that production is not affected as there was no significant production before the accident and there will be none after.
This my, friends, is not a mild problem in one part of a plant, but, in all likelihood, a serious design flaw involving a gas which is lethal in relatively low concentrations. |
