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Tuesday, November 1, 2016

Nevada Zinc - not all Zinc deposits are equal

My chum down south has been beating the drum recently about Tinka and their base metal project in Peru and showing us lots of lovely charts about how zinc prices have been shooting up. So, I took his advice and bought shares in Teck....

I can't see a difference.....
So I thought I would try and be clever and went looking for companies with zinc projects, and I stumbled on Nevada Zinc (link), they have been hitting some great zinc intercepts from their Lone Mountain project in Nevada.

I thought, at last I've found a decent project that no-one knows about, but a crap load of shares and wait for the retail investors to pile in and make me rich (ok, being realistic - slightly less poor).

I brought the drill-data into 3D (you can get the model from here).

look at those grades....

magnificent, thick, juicy zinc intercepts
Everything was looking good until I saw this in their presentation (slide 16) where it states: "Potential for sulfide mineralization at depth"

Crap, we have a zinc carbonate deposit. How many of those are operating around the world? I only know of one - the Skorpion Mine Namibia (link), that produces around 125Kt of zinc metal a year from a alluvial zinc deposit.

All other carbonate zinc deposits I know are hosted in limestone:
  • Accha and Yanque in Peru (Zincore Metals Inc (link))
  • Sierra Mojada in Mexico (Silver Bull Resources (link))
  • The tops of zinc deposits (e.g. Tsumeb, Broken Hill and the MVT deposits in the USA, UK and Ireland that were mined in the 18th century,
So they aren't common, but Skorpion is/was the 8th largest zinc mine in the world, that is good, no?

Skorpion is a bit different, most non-sulfide zinc mines are generally found in limestones, and you know what happens when you tip a load on acid on them, they fizz. Hypothetically you can leach the zinc minerals, but will have massive acid consumption.
Don't worry, Nevada zinc state that they can use dense media separation (DMS) to remove a lot of the waste and they they can leach the zinc, but that is the big issue, the real elephant in the room is the lead.

There is a bit of lead...
There isn't much, but lead carbonate, so what's the problem? Well lead carbonate is romantically called "white lead" and for the older readers it was used as a pigment in paint. Those of you who are or have renovated an old house, you know what a hemorrhoid it is to remove and dispose of the old paint.

This is what Wikipedia tells us:

It tended to cause lead poisoning, and its use has been banned in most countries...

So why is mining lead carbonate bad? Why don't we ask Magellen Metals what they think (link)?

Magellen (now called Rosslyn Hill Mining) operated the Wiluna Mine in Western Australia (link). A oxide lead-zinc deposit. Back in 2006 it was noticed that ~9000 birds died in the town of Esperance, that was discovered to be caused by lead poisoning. The source of the lead was the concentrate from the Wiluna mine that was using the port at Esperance to ship the concentrate overseas.

They also found that 10% (about 1400 people) have blood Pb levels above WHO levels. The concentrate contained lead carbonate which is absorbed much more easily that lead sulfide. The end result was that they had to pay AU$30M to clean up Esperance, and were very much under the microscope from the state government. the mine is currently closed.

So, Nevada Zinc have a carbonate zinc deposit in the USA, a country well know for being incredibly environmentally friendly. Imagine the fun you'll have with the EPA over:
  • Mining ore with lead carbonate - you gonna need good dust control
  • Transporting concentrate with lead carbonate in it
  • Having waste dumps on surface that may contain lead carbonate
    • they don't have any wind in Nevada?
I'm surprised they haven;t had a slap on the wrist for doing RC drilling, which looks like this...


Bit like a steam train, puffing all that dust over the desert. Imagine that dust contained something nasty.....

So in essence, not all zinc deposits are created equally, and if you see a company talking about their great oxide zinc depoist (e.g. Zincore, Silver Bull, Nevada Zinc), just ignore them and move on.