Geology & GeoMetallurgy

Geology & GeoMetallurgy2017-04-04T06:58:01-04:00
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Started by Hauptsturm
Busy reading an interesting report for a Narrow Vein Greenstone belt mine which uses 'sludge holes' for grade control and sampling purposes. To be honest, I have never encountered sludge holes before. I gather these are pneumatically drilled holes a...
Last commented on by PJ
Did you successfully figure out a way to catch jumbo cuttings prior to them landing on the sill?
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Started by Obersturmbann
What are the positives vs. negatives for BlastHole vs. Reverse circulation during G.C in relation to sampling errors?
Last commented on by Gravydave
Hi Dizzy, the file is no longer there. Is it still available somewhere? Cheers.
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Started by
Today I update the site's Hero image with two scatter plots of replicate samples from two drill rigs testing the same deposit. Rig A used a dump box and riffle splitter. Rig B used a static cone splitter. I have my interpretation of what is happening...
Last replied to by
It’s difficult to make a final judgement without more information. Could do with seeing Q-Q Plots to establish systemic bias and photos to establish set up - photos will probably explain most things...
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Started by
When including CRMs to monitor accuracy in a drill sampling programme the recommendation is to use more than one CRM - but what about when there are multiple variables to monitor (like sulphur and carbon). What's the best cost-effective strategy here...
Last replied to by Standartenfurer
Just coming back to this, you may have seen the paper by Nigel Brand on gold homogeneity in CRMs. Interesting data and not what I thought in terms of individual performance.
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Started by
As part of QC it is frequently recommended to use quarter core to establish that the original half core submitted is Representative. Is this achieved as there is a volume variance issue comparing half core with quarter core?Submission of quarter core...
Last replied to by Sudhirkumar
I have come late into this discussion but I wish to share the following. The 1/4 Core duplicate submission is good practice and does not need to be submitted into the lab at the same time with the hal...
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Started by OberstGruppen
I'm working on Exploration of Copper Strata bound Deposits "Manto Type Cu-Ag", and well I want to know about the Geo-chemical signature of this type of deposits?
Last replied to by Jean Rasczak
I have an old paper on meta-advanced argillic minerals, if you like.
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Started by Helena Russell
In stratified samples if we lost one strata how to deal with this situation
Last replied to by Obergruppenfuhrer
Following from earlier remarks, I would suggest that if you wish to find an optimal estimate of the missing sample assay, you should Krieg the value using the surrounding values. The process of krigin...
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Started by Oberfuhrer
Recently I did the heterogeneity test, following Pitard´s procedure, and the results showed a need to sample big masses in order to lower my FSE. I have not identified nor remove any outliers, because the grades retrieved from the test were lower th...
Last replied to by Maya Rothman
Time involved in explaining an outlier often pays greater dividends than iterative complex statistics. In the context of sub-sampling, if an outlier cannot be explained, a duplicate of that specific t...
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Started by Sturmbann
I'm looking for some suggestions on how to normalize soil assay data; it comes from a similar environment but from different labs with different LDL any suggestions?
Last replied to by
Subset the samples from the overlapping area and create a QQ plot, if all the quintiles plot on the first bisector (45degreees) then the different lab data is sufficiently similar to treat as the same...
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Started by
Twinning Drill holes - often suggested to verify existing mineralisation, for example for resource due diligence.Since mineralization is often heterogeneous, it seems to me that we are testing short range variability and not "twinning" the existing d...
Last replied to by
Tele-viewers can be inserted into RC holes and measures structural information. Diamond drill core is best if you can afford it.
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Started by Paul Morrow
I would like to understand the differences between delimitation and extraction errors because many times i think the sample suffered from both. What circumstances do you have both or either error?
Last replied to by
It is always nice if/when a procedure is available, which results in a valid estimate of the Total Sampling Error. Such a procedure is actually easy to set up, but one would likely have to know enough...
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Started by Rahil Khan
Does anyone have a free accuracy and precision checking software that allows one to easily plot Thompson Howarth, HARD, ARD, QQ Plots, Scaterplots. Even if it’s an excel based programme?
Last replied to by
Use Snowden's Supervisor. But half a day setting up in excel would do the trick just fine.
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Started by Oberstorm
I'm looking into track-mounted RC drill rigs that are used for grade control production drilling in open pit mines. Would be interested to hear what rigs (make model) are being used hole diameters and typical depths of drilling.
Last replied to by Zander Barcalow
Generally pretty good! The trick for us was to switch from RC using a hammer (standard system) to air core bit. Then for the rotary cone splitter set the dropbox gates to stay open continuously, so th...
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Started by Oberfuhrer
In exploration the goal is often to deliberately bias the sample to find trace concentration of target minerals. The classic example is panning concentrates in search of diamond indicator minerals. I'm interested in comments from members on the more ...
Last replied to by Unterstarm
Thank you for a very interesting discussion. About diamonds and panning I think, it is matter of a standardization of concentration method. It can be manual panning with people who pan the same, bette...
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Started by
I have been looking at a project where substantial coarse sample masses were generated (>20kg) which were beyond the capacity of the sampling teams to effectively handle. Due to various reasons and decisions, no QAQC samples were inserted into the...
Last replied to by
The current state is that the client has taken the samples in hand. Verified (as much as possible) that they are intact and valid. Then, and this is all hopefully because I have not had site of his ac...
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785
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Started by
Have anyone had any success with getting a reasonable sample from an ore/waste dump (the sample will define which it is)? I am assuming that RC is the way to go but are there any extra precautions (e.g. casing) which will help in getting a sample sui...
Last replied to by OberstGruppen
Perhaps a bit too late but herewith a link to a site showing you pictures of sonic applied for waste dump material sampling. The stock pile is 9 meters high and consists of brick, concrete; prefab rei...
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Started by
Has anyone had experience sampling or drilling sand tails stockpiles and dams? I am currently working on a project which is looking at using a geotech type rig. However I would be interested if anyone has experience with alternate Stockpile sampling...
Last replied to by Marshal Meru
My personal experience is very much in line with some previous comments on gold slimes dams in South Africa, i.e. relatively fine grained tailings and it works very well. I drilled down to 15m in plac...
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506
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Started by
We have used interweave sampling to verify validity of secondary and tertiary cutters with regards to the primary sampler, but still have a consistent bias in assays between mine and mill. This still leaves the possibility of a bias coming from the p...
Last replied to by Zander Barcalow
One clue I have used in the past is to look at the mineralogy/material types of the sample vs. the mine. This can often do a better job of indicating whether the sampling is introducing a bias - e.g. ...
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753
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Started by Gruppen
I need information about criteria for accept or reject a batch. Specifically for: CRMs, sum of oxides (LOI) and field duplicates. I work with nickel laterites, drilling RC-Wet.
Last replied to by Gruppen
Thanks for your comments. Reading found the following: "The errors in assays results are usually normally distributed. This means that the expected standard deviation can be used to predict the probab...
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Started by Rahil Khan
Is it necessary to consider the cut-off grade of your deposit before you can order your standard reference material to use?Again, it is necessary to put blanks within waste interval when sampling? Any advice please!
Last replied to by Rahil Khan
I am so much happy for the responses. This shows that sample is the most important product as far as exploration is concerned; hence its integrity cannot be compliance. I hope the discussion will not ...
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Started by Gruppen
I am in the interesting position of having a change in our drill and blast contractor. Our new contractor is purchasing a new downhole hammer rig that we will be able to convert to RC for shallow (50m) holes for grade control work and shallow resourc...
Last replied to by OberstGruppen
Another thing to keep in mind is the larger diameter holes and wider blasting pattern may have its own problems. It's definitely worth a trial to make sure your achieving adequate breakage. I have gon...
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Started by
Without giving away any confidential information, those of you who can, can you please provide you current best estimates of RC drilling costs per metre, and the cost of a 50 g gold fire assay for Australia - I know prices are more competitive due to...
Last replied to by Marshal Meru
As regards the 50g gold fire assay, I came across the below text in a technical note from ALS, http://is.gd/WAXPlL 'Fire Assay Technical Note 2012'. Has anyone here come across this problem before?"To...
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Started by
Is that correct using two types sampling method in core preparation samples (half core & Coning/quartering)
Last replied to by
The first question I ask myself is what is the purpose for the task you want to undertake and assess the risks of performing the task? Your major constraint will be money and resources available.For r...
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Started by
I'm looking into a particularly muddy drilling challenge and have had the Geobore S recommended. The advantage is that this can be attached to a diamond core rig. What I find on the web is the tool has been used for geotech work - I would be keen to ...
Last replied to by
It seems Geobor S works quite well on the muddy part of the tailings - not so good on the unconsolidated material near surface.
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Started by Bob Mathias
Can anybody offer any solutions to getting a reasonable sample from uphole sludge drilling in an underground mine (with the emphasis on reasonable - not perfect)?
Last replied to by Paul Morrow
There is a system around with a collar that sits around the drill rod with a hose running down to a collection system. I used it at Yilgarn Star in Western Australia many years ago as a junior geologi...
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Started by
What about of taking Reverse Circulation (RC) Drilling underground for Grade Control. What do you see as the benefits and constraints?
Last replied to by Obergruppenfuhrer
In 1999/2000, an UG RC drill programme was carried out with great success at Cullinan Diamond Mine (aka Premier). A small drill built by CUBEX was used initially to drill -12 inch diameter holes, dry....
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Started by Rahil Khan
How much ppb to ppm can be considered as MMI anomaly for gold soil Geochem?
Last replied to by Rahil Khan
Before you do or conduct any exercise in exploration you should really know about it. And specially in MMI or Geochemical samples some time it happen it show anomaly on the ground (top Soil) while you...
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Started by
There are two styles of collecting RC samples, fitted with or without a rig mounted sample splitter.Style 1: at the end of each meter sampled, the penetration of the hammer is halted and the hammer not lifted off from the bottom of the hole until the...
Last replied to by
Both of these suggested configurations are at least 15 years out of date, particularly the first one. You may be interested in the AusIMM's August Conference "Sampling 2012" in Perth. There's no reaso...
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Started by
I am looking for some feedback regarding the importance of analyzing a diamond core sample with visible gold - it is a sample I would like to see preserved as it is not yet a common sight in a deposit. However, I am not sure how to then deal with it ...
Last replied to by Marshal Meru
A target of 98% -150 M appears to significantly reduce the assay variability within the undersize product if coarse gold is present. Blending the pulverized product in disposable sample cups significa...
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Started by Tarun Karakoti
How to sample a small stockpile of coking coal?
Last replied to by Obergruppenfuhrer
The solution we have a client who did cooking coal in Germany with great success. Obviously the handling of sample and barrel is a bit challenging but can be won.
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Started by
Has anybody been convinced of the appropriateness of a continuous wet face-sampling RC program? Assuming the wet sample with copious water will flush the system clean and allow for representative sampling. Particularly in regards to an environment w...
Last replied to by Oberfuhrer
Depending on site conditions and targets, sonic drilling might be the clever answer to RC sampling problems. RC is all about cheap meterage. In some cases this may pay, but usually it is safer to get ...
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Started by Raje Singh
I am working on a Reconciliation uncertainty associated with mine production and I want to know where technical and geological activities come into play.
Last replied to by
The general opinion is that long term reconciliation is more reliable than short term reconciliation, but compensating errors can hide a multitude of sins too. One needs to be careful of reacting to s...
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Started by
When taking a 'A' and 'B' sample from a cone splitter on an RC rig and comparing those weights, what differences in weights between the two samples would you start to think there was a problem. Is this also commodity dependant e.g. gold vs. iron ore.
Last replied to by Jean Rasczak
For one specific programme, we made an RDP plot ranking difference in weights between duplicates and setting them out against variance in gold grade to see if the variance would significantly increase...
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562
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Started by
Problem - Mine grade control is reconciled back to the mill at the end of month with a single factor, effectively on a pro-rata basis. One of the ore sources commonly returns assays up to 1000g/t. Current procedure is to cut these grades to 100g/t ba...
Last replied to by
Cyclone overflows are also notoriously difficult to get a representative sample of. They contain the lowest fraction of solids (often 5-10%), so an enormous sample needs to be taken so that you can be...
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Started by Sudhirkumar
Which type of sampling method should we used in nummulitic limestone deposit
Last replied to by Zander Barcalow
I'm not sure what use you have for the limestone, but I have looked after a drilling program at a cement operation where we were drilling RC. That wasn't a nummalitic limestone and as per what earlier...

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