MineralThe formula
Estimated true width = downhole interval × sin(angle to the body plane). Use degrees.
How to use the result
Use a straight interval crossing two parallel, planar contacts. Enter the acute angle between the hole and the body plane: 90° is perpendicular to the body; an angle close to 0° runs almost along it. This is not the collar dip or the angle to the body’s normal. Both the hole orientation at the intersection and the body orientation must be known. Curved holes, folds, irregular contacts and uncertain geometry invalidate this simple estimate. If geometry is unknown, true width remains unknown.
One interval, different geometry
For the same illustrative 20 m downhole interval, the estimated thickness increases with the angle to the body plane. These are geometric examples, not assay results.
| Angle to body plane | Estimated thickness | Share of interval |
|---|---|---|
| 30° | 10 m | 50% |
| 45° | 14.1421 m | 70.7107% |
| 90° | 20 m | 100% |
A 0° crossing is excluded: a straight hole parallel to the contacts cannot cross the full thickness of this idealised body. Near-parallel estimates are especially sensitive to small angle errors.
Why orientation must be disclosed
JORC Code 2012, Table 1, Section 2 calls for disclosure of the relationship between drill orientation and mineralisation width when known, and a clear statement when only downhole lengths are available. The calculator applies elementary trigonometry; it does not determine a project’s geometry or establish a mineral resource.
Method reviewed Sep 5, 2026. Examples are illustrative, not company data.