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Desperately seeking HELLLLLLLLPPPPPP!

03/14/2008 4:43 PM

Do you ever wonder what it's like to be in a position where you are being asked to come up with solutions to questions way above your technical expertise. Of course you do and some of you come here for those answers, so here I am.

I'm a "Metallurgical Technician" at a copper mine (Technician in title only, not background). The problem laid at my feet was to come up with a method to test the SG of our copper concentrate as our physical reconciliations are constantly out to lunch. Our reconciliations also depend on the physical measurement of our product as it sits in a shed awaiting shipping. It gets to this shed by conveyor system and is dropped about 30-35' (in a perfect world the pile would always be a nice cone). It has a varying moisture content as well (7-10% H2O). So being as more is constantly dropping on the pile, the bottom of the pile would be more compact and therefore more would be in less space (volume wise) at the bottom of the pile. So I am asking for your help on two main things:

1. What is a good method to use to determine the SG of the copper concentrate?

2. How can I apply it to helping fine tune our measurements to get a more accurate reconciliation?

If anyone has any ASTM method concerning this, I would love to have a peak at it . I have looked high and low on google for any comparable help to my situation and I struck out , so any and all help will be greatly appreciated. Thank you for your time and efforts.

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#1

Re: Desperately seeking HELLLLLLLLPPPPPP!

03/14/2008 5:18 PM

I guess a couple of questions come to mind. I'm not too familiar with the detailed workings of a copper mine, so please excuse any dumb questions.

1) What are you reconciling against? How and at what point in the process is this data gathered?

2) Where do you want to measure the SG of your product? As it lies in the pile waiting for transport or prior to being dumped on the pile?

The only way to determine SG is to measure the weight of a known volume of material - it is inherently a "batch" process. I am not aware of any method to measure SG "on the fly". You need to settle on a few factors that will drive your procedure.

a) What is your desired accuracy? 10%? 1%? 0.01%?

b) At what standard compaction and water content will measurements be performed? A calculated correction for each of these should be possible, but it is necessary to have a common point of reference to compare all measurements to.

c) How often are measurements required?

This is your first step: defining what form the information need to be in so it is useful information. I suspect that a large part of your reconciliation problems have to do with the quality of the data you're reconciling against.

Does that help get you started at all?

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#2
In reply to #1

Re: Desperately seeking HELLLLLLLLPPPPPP!

03/14/2008 11:33 PM

Hey CSM Engineer, thank you for your quick response. I would have replied sooner, but the work week was over and I was getting ready to wind up my day. I am at home now and hopefully I can clarify some of the questions (none of which are dumb).

1. There are a number of things to reconcile against. Cu grade of the ore going in (heads), grade of the waste ore going to tailings (Tails) and grade of the concentrate itself (conc). All of these grades when matched against the tonnage milled (feed or head material) will produce a "recovery" percentage which can then be used to determine how much Cu conc should have been produced. The Cu conc is also measured by a weightometer on the conveyor to the shed, the scale weights from the transport trucks and the scale weights of the rail cars used to transport it to the dock from where it is shipped to a smelter. A reconciliation would be used to "prove" or ferret out the best number and find deficiencies in others (I am GUESSING now).

2. As it lies in the pile, to give us a more accurate idea of the amount present

a) Our desired accuracy...well compared to what we have in place now I don't think it would be hard to improve, so to answer, anything within 10% would be a godsend.

b) I'm not sure I understand your point, but I'll add that our moisture content is variable, and compaction (some test ideas have been discussed) will depend on the depth the concentrate is located in the pile.

c) Measurements of the shed are being asked for on a weekly basis, with a final month end done regularly.

If you have any ideas how to achieve what we are looking for, it would be greatly appreciated.

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#4
In reply to #2

Re: Desperately seeking HELLLLLLLLPPPPPP!

03/15/2008 2:32 AM

b) I'm not sure I understand your point, but I'll add that our moisture content is variable, and compaction (some test ideas have been discussed) will depend on the depth the concentrate is located in the pile.

Therein lies your challenge. I think you intuitively grasp that these factors will impact your SG results. You need to determine what moisture content and compaction will make your results meaningful when reconciled against the data you listed behind 1). I expect you will have to take some known grade of ore and follow it through the milling process to determine exactly what moisture content and compaction of concentrate will yield a SG that reconciles properly. From there you should be able to chart SG's at various moistures and compactions to derive correction factors to use on other samples to give the results meaningful relation to the data you need to reconcile against.

In other words if you start with a known 'x' and expect a result 'y', you need to define through experiment what analytical methods will consistently yield 'y'. Once you have proven your analysis method and determined your correction factors to use at non-ideal moistures and compactions, you should have the tools to take random samples and produce results that will reconcile meaningfully.

Does that make sense, or am I off on a tangent somewhere?

BTW - I don't expect a response from you before Monday. Enjoy your weekend!

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#8
In reply to #4

Re: Desperately seeking HELLLLLLLLPPPPPP!

03/17/2008 1:34 PM

Thank you! It makes sense (or at least it seems to me, with what little grasp I do have on some of the ideas discussed). It's just so overwhelming due to the fact that I don't think I have ever worked at a mine where the reconciliations were "accurate" (being relative to what the mine manager figures is a good error).

There are so many factors: moisture, Cu grade, Fe grade, if the pile was "organized" in the shed by the truck loader, whether the filter operator was cross-eyed (sorry sarcasm has developed to a peak today), etc... I will be compiling the ideas that I have "gratefully!!!!!!!" (not sarcasm, thank you and everyone very very very much for the help) recieved here and throwing them up line from me to see if there are any that I can get some guidance on. Thank you all again for your time. I may need to ask for "HELP" again soon though .

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#3

Re: Desperately seeking HELLLLLLLLPPPPPP!

03/15/2008 12:26 AM

Well why overcomplicate ore redesign the wheel. Your ore is a soil, and location in the pile is a false variable, affecting only your test, not the actual properties of the material stream, just material at a particular locus in the pile.

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#9
In reply to #3

Re: Desperately seeking HELLLLLLLLPPPPPP!

03/17/2008 1:46 PM

Thanks for the link. I've added it to the list of tools to take into consideration for refining (no pun intended) our process of reconciliations.

Believe me I do not want to over complicate things anymore than they already are (too many things on the go that are all "priority one" if you catch my drift. As mentioned in a previous response, there are a lot of variables that are causing us headaches (not to mention a pile in the shed that needs a mountain goat to scale to take a good look at for measurements).

Once again, thank you very much for the input. I'll let you all know what comes of it.

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#5

Re: Desperately seeking HELLLLLLLLPPPPPP!

03/15/2008 5:54 AM

By all means try and do it, and treat it as an oportunity, but be sure to keep charge of any new found expertise, and press for a payrise or promotion.
Be aware that management will happilly take any kudos (and bonus) if you succeed, and blame you if there is no improvement.

It strikes me that the management at the mine are a bunch of cheapskates who are pressing you to do this work on the cheap instead of employing someone qualified.

This may sound like a jaded view of the workplace, what I'm really trying to say is ...
Good luck, but be sure to 'blow your own trumpet' , as you can be sure no-one else will.

Del

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#10
In reply to #5

Re: Desperately seeking HELLLLLLLLPPPPPP!

03/17/2008 1:55 PM

The famous Del!

I am honoured to receive a reply (how does it feel to have yet another fan?) and encouragement from you!

Thank you for the pointers, believe me if I come up with something people around here are interested in promoting (and by "I" I mean with all the great help here), I will be asking for some $$$$.

I'm not sure if you are familiar with the boom in mining lately, but there has been such an influx of operating mines that the people needed to run them from labourers to engineers are hard to come by. This is why I think more and more is being asked of workers like myself. I do not know about "cheap" (yeah I'd like to be paid more, but who wouldn't), but our size might limit what we are able to offer new prospective "qualified" employees, so they end up going elsewhere.

Thanks again for the encouragement and advice!!!

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#11
In reply to #10

Re: Desperately seeking HELLLLLLLLPPPPPP!

03/17/2008 1:59 PM
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#14
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Re: Desperately seeking HELLLLLLLLPPPPPP!

03/17/2008 4:45 PM

"(how does it feel to have yet another fan?)"

Now stop that, you'll swell his head right up, and he'll choke from his flea collar!

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#6

Re: Desperately seeking HELLLLLLLLPPPPPP!

03/15/2008 10:59 AM

efuddster-- you say you are not a"Technical Expert".

Not to worry-- you have company here.

But you did a good job oF stating the problem. They say --'If you can state the problem-you have half solved it'.

Let us revisit your stated problems:

1. SG of anything-- heard of Archimedes' -- "Eureka"-- nobody bettered it YET.

Automatically Grab samples off the belt every 5/10/30/60 MINUTES(as our friend already quoted Peoples' Republic of California orders to)-- and Auto Analyze.Keep a computerized databank. At a MouseClick at any (say a year later)you can see "Average" SG on Hourly/Daily/weekly/Monthly basis.

Move with times . Do not just stop at SG. Go a step further- have Cu content --mass%-- analyzed spectroscopically at the same sampling and store readout in the databank together{ Cu%,SG}. So then -- the answer to 1 is "Create DATABANK". With Cu prices skyhigh your Company can afford anything--NOW!

As DELd'CAT rightly hinted-"Get youself promoted to"Tech. Director" at this chance.

2 All that is there in above solution .

Your Q3 will be "How to go about doing all the above"

A3 Float a reworded "HELP!!!" Thread in Good Old CR4. You will be flooded.

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#12
In reply to #6

Re: Desperately seeking HELLLLLLLLPPPPPP!

03/17/2008 2:02 PM

Mukulmahant, thank you for the insight! The steps you provided along with all that has been posted here will hopefully get me going in the right direction (provided I can get some support here on my end of things). I like the idea of logging everything, but I can just hear the groans of protest over the man power and logistics that they envision it will take to complete. I know there is a way to do this, and if they want it done, they're going to have to commit some man hours to this project (I can guess my man hours ). I just hope this is something I can see through to the finish (focus tends to change fast around here somedays) or else I'd just as soon not start it.

Thanks again for the help!!! (I will see what comes of what I have gratefully recieved here before I repost, very good tip)

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#15
In reply to #12

Re: Desperately seeking HELLLLLLLLPPPPPP!

03/17/2008 4:50 PM

Sounds like you'll first off have to remind the great faceless voice of authority that not everything can BE first. Gotta prioritize, and this sounds like it maybe DOES belong near the top of the pile (so to speak...). I think you can make a case for a composite grab sample from several locations/depths being a representative sample, but in future, you should start earlier into the pliing process...

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#7

Re: Desperately seeking HELLLLLLLLPPPPPP!

03/15/2008 8:26 PM

I agree with the other posters, but would add that it would likely be to your benefit to run a Wikipedia search or Google search on various measures of SG and look at the definitions of bulk density, true density and apparent density.

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#13
In reply to #7

Re: Desperately seeking HELLLLLLLLPPPPPP!

03/17/2008 2:18 PM

Thanks for the advice agua doc! I'll attempt just that (I just hope they can dumb it down a bit so I understand the principles of what they are explaining).

Thank you all for your help to date!!!!!!!!!!!!!!!!!

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