MineralA drill result describes the material sampled along a hole. Read the reported grade together with its interval length, location and relationship to the mineralised body.
What to check
| Field | Question to ask |
|---|---|
| Grade and units | Is the assay in g/t, percent or ppm, and for which element or compound? |
| From, to and interval | Does the interval equal the difference between the downhole endpoints? |
| True width | Is true width estimated, known or explicitly unknown? |
| Aggregation | Are internal waste, cut-off grades and high-grade subintervals explained? |
| Geometry | Where is the hole on the section and relative to the other drilling? |
JORC’s 2012 reporting checklist explains that geometry, aggregation methods and the relationship between intercept length and mineralisation width should be disclosed. It also calls for the assumptions behind metal-equivalent results. Read Table 1, Section 2 of the JORC Code.
Keep the arithmetic separate from the geology
Multiplying grade by reported interval gives a grade-length product. It does not establish the deposit’s volume, continuity, recovery, cost or economic viability. Do not add an “including” subinterval to its parent interval: that counts the same rock twice.
Use the gram-metre calculator for transparent arithmetic, and return to the original issuer disclosure for context.