Geologists discussion thread!

Iv'e got one for a geo. I've been noticing Magnesium Oxide (MgO) referred to often in relation to nickel resources.

Is the MgO troublesome in extracting the nickel and can the magnesium be seperated as a saleable product as well?

derty said:

I cannot see why not lazyfish, the main irritants in the job would be dust or fumes. Due to Occ Health and Safety issues dust is usually suppressed while surface drilling or in open cut mines. In underground mines there may be some dust when bogging out recently fired headings or stopes, though the miners usually try and water down the dirt quite well before hand. While ventilation underground is usually adequate, diesel fumes can become quite noticeable in areas where there is a bit of activity and a geo will use quite a bit of spray paint underground with the airborne atomised paint being very irritating, even for a non-asthmatic.

I'm sure there are many asthmatic geo's about and there are plenty of jobs within geology that would be as hazardous as a standard office job in a city. An exploration geo would have the least exposure to dust other than air based drilling (RC, aircore or RAB). If you are at a rig creating a lot of dust you can move or better still as you are managing the drilling program enforce that they use dust suppression (water based is the best) or improve the dust suppression they have.

At the end of the day it depends on what triggers the asthma.

Click to expand...

Thanks, that's really good to know

Whiskers said:

Iv'e got one for a geo. I've been noticing Magnesium Oxide (MgO) referred to often in relation to nickel resources.

Is the MgO troublesome in extracting the nickel and can the magnesium be seperated as a saleable product as well?

Click to expand...

When MgO values are talked about with respect to nickel sulphides it is usually as smelters require a certain MgO:FeO ratio as high MgO concentrates cause problems within the smelter. The higher the MgO the higher the temperatures required to sufficiently melt the product which increases energy costs and can damage the furnace.

Now a bit of background:
Nickel sulphides occur within komatiite, a very high MgO% ancient volcanic rock that erupted at temperatures in excess of 1600 degrees C. The first minerals to crystallise from the lava are olivine (MgSiO4) at 1600 C, giving you an indication as to what temperatures are needed to remelt the stuff. The original rocks have been altered in all that time and there is no olivine left now, it has been replaced by either serpentine (Mg silcate) or talc (Mg silicate)+magnesite(Mg carbonate). Either way the MgO is still there.

With the nickel sulphide ore types you have two end members. Massive Ni sulphides (eg Kambalda/Black Swan) where you have >80% sulphide and <20% silicate material and disseminated Ni sulphides where the sulphide content is often <5% with the remainder being high MgO silicate material (eg Mt Keith with MgO% often >50%). Typically the concentrates produced from disseminated sulphides will have a high MgO:FeO and those from massive sulphides will have a low MgO:FeO.

The trick then is to blend your high MgO and low MgO concentrates. The low MgO:FeO concentrate from Kambalda is crucial to the BHP Kalgoorlie smelter to offset the Mt Keith and Leinster concentrates. The MgO can also be diluted by addition of silica or other barren sulphides.

As for using the Mg as a by product: The Mg% in analysis is typically quoted as an oxide i.e. MgO, though in actual fact it is present as a complex silicate and would not be economic to extract in comparison to MgCO3 (magnesite) which is the main source of Mg.

Thanks for that derty.

I did find some highly technical stuff on the subject, but the language was way over my head to understand much out of it.

You have explained it well in relatively simple language. Answered my query nicely, thanks again.

derty said:

Now a bit of background:
Nickel sulphides occur within komatiite, a very high MgO% ancient volcanic rock that erupted at temperatures in excess of 1600 degrees C. The first minerals to crystallise from the lava are olivine (MgSiO4) at 1600 C, giving you an indication as to what temperatures are needed to remelt the stuff. The original rocks have been altered in all that time and there is no olivine left now, it has been replaced by either serpentine (Mg silcate) or talc (Mg silicate)+magnesite(Mg carbonate). Either way the MgO is still there.

Click to expand...

Great info here derty,

I am also learning a lot about nickel as well!

jman

Spaghetti said:

Well not sure if my question is geology or chemistry but will give it a try. Trying to sort out real hopefuls from the hype in iron ore sector. Hype just does not pay like it used to!

Was reading an article that said most iron ore in WA will never be mined due to high P% and that it is needed to be significantly less than 1%. Now I could understand "less than" but "significantly" isn't really helpful. Anyone know an actually level that is acceptable. Like .09% or .08%. Same article said same for sulpur yet sulpur levels not included on reserve tables.?

Also was reading a thread here regarding a stock that has high grade ore but was mentioned the high silica level would present problems. Again can anyone assist is acceptable levels of silica.

This article is a great read and leads you in the right direction except not very specific in terms of % for impurities.
http://www.doir.wa.gov.au/documents/GSWA_IronOreInWAPamphlet.pdf

Thanks in advance if anyone can assist.

Click to expand...

Hi Spag,

Anyone here got the lowdown on acceptable levels of impurities for bulk commodities like iron ore, so we answer Spaghetti's question?

The P-issue is an interesting one. I know AXO who are developing the Balla- Balla magnetite project are conducting metallurgical testwork on material in the hanging wall of the deposit for phosphate potential. But this does sound more like an adjacent body of potentially economic mineralisation, rather than an actual "impurity" in the magnetite itself.

So I wonder where the cutoff is between an "impurity" and an economically extractable by-product?

Will have a read of the link and get back to you.

jman

Hi Jman

Though still confused have learned a little more. Have read sulphur is easily removed via benefication so would only be an issue for DSO, but then it would not be called DSO ! So I have no concern on sulphur based on the little I know.

Phosphorus as I understand, is difficult to separate so low content preferable to begin with. I did read a thesis type of report after google, on separation of phosphorus using flotation tank (sounding like base metals here) on low fe content magnetite ore but was in science speak and obviously research level, so like a few kilometres over my head. Would be good is they developed a way and we knew which deposits would then be a goer. Always handy to know these things Seems any effective removal of phosphorus leads to high rate of fe loss as well.

You would never believe but after 5,000 google searches the only acceptable level of phosphorus impurity even mentioned came by way of a aussie stock forum post dating back to way back on YML thread, comment from Kauri who suggested .08%. Why google when the answers are here all along

Silica levels still stump me, seem to depend on whether ore is destined to be iron or steel end product. Also sintering may remove silica from fines or perhaps I have no idea what I am talking about. More than likely, all very interesting and complex though.

Hi guys,

Back for more questions. I have applied for a summer job with a mining company as a mining geologist (student). They operate open pit mines. They are sending me for a medical exam. Could anyone please tell me what this exam is all about?

Thanks in advance!

Just an update of phosphorus levels of iron ore from Ferraus report 2007, nt sure if demand has changed acceptable levels or not over time or of processing techniques have improved.

http://www.abnnewswire.net/press/en/35200/FERRAUS-LIMITED.html

Phosphorus content of the iron mineralisation is generally low-moderate (0.06-0.11%P), while limited areas with high phosphorus contents (>0.12%P) are seen associated with increased hydration and manganese. Penfold Limited, a marketing company and major FerrAus shareholder, has confirmed with Asian steel mills that iron ore products containing 0.08- 0.12%P are acceptable and remain in demand as blending feedstocks. The level of other contaminant elements (Al2O3, SiO2, Mn, S) were also confirmed as acceptable

Click to expand...

So less than .08 for stand alone saleable product (dependant of course on other factors) and upto .12 for blending feedstock which I gather would attract a price penalty.

lazyfish said:

Hi guys,

Back for more questions. I have applied for a summer job with a mining company as a mining geologist (student). They operate open pit mines. They are sending me for a medical exam. Could anyone please tell me what this exam is all about?

Thanks in advance!

Click to expand...

same as any medical... a company doesnt want to invest significant amounts of money in your development if you have any sort of health issues preventing them from reaping returns on their investment...

the mining companies seem to be pretty hot on the drug screening as well... they dont want any cowboys out on the mine sites... hope youve been staying off the googs during your uni days

Hey geologists - can anyone give me an explanation of what a 'strip ratio' is i.e. what is a high strip ratio and what is a low strip ratio?

From my basic understanding of the term, there is a correlation between the strip ratio and the mining cost?

Bushman said:

Hey geologists - can anyone give me an explanation of what a 'strip ratio' is i.e. what is a high strip ratio and what is a low strip ratio?

From my basic understanding of the term, there is a correlation between the strip ratio and the mining cost?

Click to expand...

Strip ratio is the number of tonnes of waste that needs to be removed in order to extra one tonne of ore. For example superpit has a strip ratio somewhere between 6 and 7 meaning that every truckload of ore comes with 6-7 truckload of waste. I don't know what is a low strip ratio, it depends on the commodity and grade as well I guess.

Therefore there is a direct relationship between strip ratio and mining cost.

G'day All

I have been following an Iron Ore company, and I am just wanting to learn a bit more about the drilling process and then defining the resource and converting into JORC.

I am particular interested to learn more about the different stages in the process, from drilling it out, to testing the drill samples, to converting it to JORC. I am also having trouble trying to understand where all the following terms come into it "Indicated", "Inferred" "Converting Resources to Reserves" etc.

Any basic information on the process for a simpleton like me, would be much appreciated.

Pythagerous, if you check post #3 in this thread by jman it is a good introduction into JORC and the different resource and reserve classifications.

Also have a look here for detailed JORC info: http://www.jorc.org/

This link gives a good run-through of generic exploration processes: http://en.wikipedia.org/wiki/Mineral_exploration

Also if you have a read of this thread from go-to-whoa you will answer quite a few of your questions and probably quite few unasked ones too

Good description of the potential of VMS districts i.e. VMS deposits within the Bryah Basin (hosts SFR's DeGrussa).

'D. F. Sangster from the Geological Survey of Canada conducted a study on eight precedent VMS districts in Canada and Japan. His findings include ¹:The VMS districts studied contain between 4 and 20 deposits, with an average of 12 deposits. The average total base metal content per district is 5.4 million tonnes. In order of size, the largest deposit in each district contains, on average, 65% of the total metal and the second largest about 13%.'

Bump ... as per my earlier post. Some good stuff on here. chrs