Glossary · Drilling
True width vs apparent width
True width is the perpendicular thickness; apparent width (downhole length) over-states it when the hole intersects mineralization at a shallow angle.
When a drill hole intersects a mineralized vein or layer, the downhole length is always equal to or greater than the true width. True width is the actual perpendicular thickness of the mineralized body. Issuers are required by NI 43-101 to disclose whether reported intercepts are true width or downhole length; when only downhole length is reported, the intercept is flagged as apparent-width-only and investors should discount it accordingly.