Intercept Charts
The Corebox Intercept Chart plots grade versus intercept length and is used to compare drill intercepts.
The chart is particularly useful for:
- Evaluating early stage exploration projects
- Comparing recent results with previously announced intercepts.
- Determining the significance of a particular intercept.
Key features:
FAQs
How are the comparables (grey dots) chosen?
The comparable data points come from companies that display drill data on Corebox. To make the comparable intercepts as meaningful as possible, we include only those intercepts that contain the same primary commodities. For example, properties reporting gold and silver intercepts are compared with other properties reporting gold and silver.
Why doesn't Corebox take into account metal recoveries?
Not all companies have completed metallurgical studies that provide estimates of metal recoveries. To compare all intercepts on an equal basis, we ignore recoveries when calculating metal equivalents.
Do you have results for XYZ company?
If you're looking for a particular company or property, either phone the company and ask for a link to their Corebox display, or check our list of publicly available properties.
What do the diagonal lines indicate?
All intercepts plotted along the diagonal line have the same grade-width. Grade-width is a rough measure of intercept significance. The greater the grade-width the more important the intercept.
Grade-width is calculated by multiplying the grade of the intercept by its length. For example, an intercept that contains 10 grams gold per tonne over 2 metre has a grade-width of 20.
Are subintervals plotted?
Yes, all intercepts that a company provides to Corebox are plotted. For example, if a company provides a low grade interval along with a highgrade subinterval, the scatter plot will plot two dots -- one for the highgrade interval and another for the low grade interval.
Why do some company's intercepts plot in vertical columns?
This is normal and occurs when a company assays its drill core or cuttings at predetermined intervals. In such cases, the composite intercept length will always be a multiple of the assay interval ie: 2m, 4m, 6m etc.
In cases where assayed length varies, the published composite intercept lengths don't have uniform lengths and so don't plot in vertical columns.
How is the grade equivalent calculated?
Corebox converts poly-metallic intercepts results into a grade equivalent using current prices. For example, if an intercept contains both gold and silver and gold is worth 60 times more than silver, we would calculate a gold-equivalent by multiplying silver times 60 and then adding that number to the gold value.
Below is a table of commodity prices that we've used to calculate these equivalents. We will update these prices on an as-needed basis. Please contact us if our commodity price table needs updating.
| Commodity | Spot price($USD) | Source / Note |
|---|---|---|
| Gold | 1330 /oz | Kitco - October 2010 |
| Silver | 23 /oz | Kitco - October 2010 |
| Copper | 3.8 /lb | Kitco - October 2010 |
| Nickel | 10.5 /lb | Kitco - October 2010 |
| U3O8 | 52 /lb | UXC - October 2010 |
| Zinc | 1.17 /lb | Kitco - October 2010 |
| Lead | 1.17 /lb | Kitco - October 2010 |
| Mo | 14.8 /lb | LME - October 2010 |
| MoS2 | 8.88 /lb | Mo $/lb divided by 1.6681 |
If a commodity is not listed in the above table, the commodity's value is not used in the grade-equivalent calculation. An asterisk beside the commodity name is used to identify such commodities.
How can I see the mineral or metal grades used to calculate the equivalent grade?
Corebox makes available the mineral or metal grades used to make up each plot point. Point your mouse at any orange or blue diamond to see the details of the intercept. To see the details of any comparable intercept, visit the property's Corebox profile by clicking on the comparable dot and then viewing that property's intercept chart.