It's an interesting topic and lot's of companies in the game have differing views, mainly to suit their needs in terms of feel good reports to potential investors...bit like lipstick on a pig, to make it look better.
As Fangulator points out,the porphry copper deposits are the most common and widespread globally.
Main copper ore minerals are:
Chalcopyrite : CuFeS2 ..note the Iron atom, makes it harder to separate the Cu from the molecule.
Chalcocite: Cu2S ... note the lack of iron..this makes the copper separation a lot easier.
Then we also have Malachite,apart from many other mineral permutions containing Cu.
Malachite: Cu(CO3)3 (OH)2 .. this lacks iron and Suplhur and is an "oxide"style mineral ,Hydroxide in this case.
So what constitutes a world class deposit in relation to the above? Well I have pasted a part of an analysts' viewpoint below and the rest of it you can read in the link below that.
Then have a look at the BHP Billiton link for the Olympic Dam expansion. and also a link giving a bit of history on Copper mining in South Australia..it may interest you to find that SA had the richest copper mine in the world at one stage. SA has a lot of copper,mainly sulphide mineral. It all about the size of the resource not so much the grade.
Happy reading, you still have the rest of the weekend to read up so here's a few leads.It may help answer a few queries.
World Class Deposits
Copper occurs in many forms, and in a variety of geological settings. There are various factors to consider in determining the value of a copper deposit. "
Historically, the most profitable mines have been large scale porphyry deposits, with chalcopyrite mineralization extracted via open-pit mining.
When assessing the potential of a copper deposit, exploration companies consider the estimated copper resource, the grade of the copper, the ease at which the copper can be mined and the cost of refining the copper. However, the most profitable mines with their porphyry deposits and chalcopyrite mineralization defy this logic because the grade of the ore is not the highest, and the refining costs are more expensive. However, due to the fact that chalcopyrite is formed in a variety of geological settings, within various mineral assemblages, chalcopyrite deposits have the largest overall resource.
The total size of the reserve often trumps grade and refining costs.
One of the largest copper mines in the world is the Escondida mine in Chile.
Escondida means “hidden” in Spanish, and the deposit was given the name because there are no outcrops; in fact the main orebody is hidden below hundreds of meters of overburden.
Copper production figures change rapidly, but in 2007 Escondida was the highest producing copper mine in the world. In 2007, the mine produced 1.483 million tonnes of copper worth US$10.12 billion.
Escondida produces mainly copper concentrates, and SULPHIDE ore, which contributes to 77 percent of the recoverable copper reserve."
You should all have a read of the BHP report on the Olympic Dam mine/resource...just to give you an idea of scale and low grades being very profitable....however,you need to apply lots of money to make it work..this is not micro speccie territory!
Back to my wine and a bit of homework.
Cheers
HR
No advice given or intended .. best to know a bit on the Resource your putting your hard earnt money into. Hope that helps without getting very technical.
