I am brand new to the idea of choosing my own investment portfolio, but I have been invested in bullion for the last five years. I am now starting to look into the junior mining companies, but I am not sure how to visualise drill result data. For instance:

Hole number: SZR006
From (meters): 48
Width (meters): 3
Grade (g/t Au): 1.6
Intersection: 3m @ 1.64g/t Au from 48m

My understanding is:

Hole number: This is simply a reference to a given drill hole;

Grade: This is the amount of the mineral (gold) that can be derived from 1 tonne of mined ore, assuming a 100% extraction rate.

I am having difficulty visualising how from, width and intersection map into three dimensional space:

If the drill hole is vertical, then is from the depth of the mineralisation from the start of the drill hole? So, the drill hole starts at the surface which is 0m, and extends down to 48 meters before it finds any mineralisation?

Imagining a cross-section through a geological formation, and a drill hole going down vertically, is the width the distance between the left most and right most extent of the deposit? So the deposit would be 3 meters wide?

What is the intersection?

So, in the above example, we would have a drill hole that starts at 0m and goes to a depth of 48 meters without finding any mineralisation. After 48 meters, it find mineralisation that has a width of 3 meters? They do not know how deep the mineralisation goes down, and hence they don't give a number for the end of the mineralised deposit?

Thanks for any help in getting me to understand this type of data!

Hello doahh.
If you posted a link to the news release, I could be sure of my assumption. Barring that, I would assume that they mean from the 48 to 51 meter interval, they encountered 3 meters grading at 1.6g/t Au.

Thanks for the reply.

The data was taken from Helio Resource Corp drill results.

So, it would mean that from a depth of 0m to 48m, there was no mineralisation. Then from 48m to 51m, there was mineralisation. They would then drill more holes in order to find out how far that vein extended to in various directions until they had mapped out the full dimensions of the vein. The vein may of course slant up/down etc.

The intersection is therefore a quick way to write that which I have put above. In fact, the intercept data is enough on its own to understand what the extracted core is showing.

That seems to make sense, but please correct me if I am wrong.

These were posted as significant drill hole samples. These were core samples that were processed, and these were the results. I find these tables confusing by themselves. I will usually take the time to look over the map, plot out the drill holes, then look over the intecepts. For the SMP project in Tanzania, there are several zones they are investigating. Some is infill drilling on an existing resource, some is diamond drilling at newer zones.
Plotting the holes on the drill map will give you a 3D idea of an ore body(s) developing. Looking at intercepts without the drill map won't show you much. Usually there is a description of the kind of drilling, and the intention of that drilling relative to what they wish to prove/disprove. Is this diamond drilling, or infill drilling. Do you recall what zone, and what they were trying to accomplish? It all needs to be in context.

doahh wrote:
I am brand new to the idea of choosing my own investment portfolio, but I have been invested in bullion for the last five years. I am now starting to look into the junior mining companies, but I am not sure how to visualise drill result data. For instance:

Hole number: SZR006
From (meters): 48
Width (meters): 3
Grade (g/t Au): 1.6
Intersection: 3m @ 1.64g/t Au from 48m

My understanding is:

Hole number: This is simply a reference to a given drill hole;

Grade: This is the amount of the mineral (gold) that can be derived from 1 tonne of mined ore, assuming a 100% extraction rate.

I am having difficulty visualising how from, width and intersection map into three dimensional space:

If the drill hole is vertical, then is from the depth of the mineralisation from the start of the drill hole? So, the drill hole starts at the surface which is 0m, and extends down to 48 meters before it finds any mineralisation?

Imagining a cross-section through a geological formation, and a drill hole going down vertically, is the width the distance between the left most and right most extent of the deposit? So the deposit would be 3 meters wide?

What is the intersection?

So, in the above example, we would have a drill hole that starts at 0m and goes to a depth of 48 meters without finding any mineralisation. After 48 meters, it find mineralisation that has a width of 3 meters? They do not know how deep the mineralisation goes down, and hence they don't give a number for the end of the mineralised deposit?

Thanks for any help in getting me to understand this type of data!


These are great questions as they are ones which all "newbies" need to have clarified at some point.

If I'm reading your remarks right, what you have surmised is largely correct:

The "depth" numbers NO measure the distance from surface to mineralization.
The "width" numbers ARE the VERTICAL length of the mineralization (in the core sample).
The "intersection" is the VERTICAL cross-section which the drill extracts from the Earth.

Where things get tricky is that quite often the mineralization does NOT run "laterally" through the "strike length" of the deposit. Instead, it's not uncommon to see ore deposits which slope at considerable angles.

So in those instances, to get what they call a "true width" the angle of drilling must be adjusted so that the core sample reflects the most ACCURATE "width" of the the deposit.

And naturally any time we're dealing with three dimensional representations, what is "width" and what is "length" and what is "thickness" all depend on your orientation. So (arbitrarily) it was decided that they would refer to the VERTICAL dimension of an ore deposit as "width" and the LATERAL dimension of the deposit as "length".

When it comes to showing the "thickness" of a deposit (the last of the three dimensions), look for phrases like "step-out drilling".

Stuff like this does NOT always sink in immediately, so if you (or anyone else) want any part of this clarified, just ask more questions.

When I was younger, I tortured COUNTLESS teachers/professors with endless questions. Now this is MY "karma"...

Brian Boutilier wrote:
Do you recall what zone, and what they were trying to accomplish? It all needs to be in context.

No, my question was a very high level (newbie) question, without any specific purpose behind it. I just used the data from the Helio Resource Corp as I happened to have it to hand. I was trying to understand how the data given would translate into 3D space. I have been looking at drill data over the last few days and was just trying to get a better feel for it. I think I understand how to read it now, and I understand that the next stage in actually using the data for something constructive would be to plot it on a map.

Jeff Nielson wrote:

The "depth" numbers NO measure the distance from surface to mineralization.
The "width" numbers ARE the VERTICAL length of the mineralization (in the core sample).
The "intersection" is the VERTICAL cross-section which the drill extracts from the Earth.

...

And naturally any time we're dealing with three dimensional representations, what is "width" and what is "length" and what is "thickness" all depend on your orientation. So (arbitrarily) it was decided that they would refer to the VERTICAL dimension of an ore deposit as "width" and the LATERAL dimension of the deposit as "length".


That makes sense, thanks to both of you for taking the time to help me understand this.

School is always "in session" around here.



P.S. If you haven't noticed this yet, check out our "Education Vault" (the flashing box in the center of the page right below our "Videos" section).

Half is devoted to "bullion information" and half is devoted to the "ABC's" of the miners.

Yes, it is a great resource. I read all of the articles before starting to read up on specific companies. I have to say thanks for putting it together. It is difficult to get a feel for this sort of thing if you are not a trained in a relevant area such as economics or finance.

I also got the idea of looking into Helio from this site, it does look interesting. I am just starting to look into Gold Bullion Development Corp (GBB.V). I think I should learn quite a bit by making a comparison of the two.

I found this handy little tool from a link at GEI's mining and precious metals section:

www.corebox.net/properties/smp-gold/porcupine-quill

there are quite a few companies there, it certainly makes visualisation of drill data easier.